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Principles of Arc Extinction in Circuit Breaker Before discussing the methods of arc extinction, it is necessary to examine the factors responsible for the maintenance of arc between the contacts. These are : - potential difference between the contacts. - ionised particles between contacts Taking these in turn, Methods of Arc Extinction in Circuit Breaker - High resistance method - Low resistance or current zero method. 1. High Resistance Method - Lengthening the arc – The resistance of the arc is directly proportional to its length. The length of the arc can be increased by increasing the gap between contacts. - Cooling the arc – Cooling helps in medium between the contacts. This increases the arc may be obtained by a gas resistance. Efficient cooling blast directed along the arc. - Reducing X-section of the arc – If the area of X-section of the arc is reduced, the voltage necessary to maintain the arc is increased. In other words, the resistance of the arc path is increased. The cross-section of the arc can be reduced by letting the arc pass through a narrow opening or by having smaller area of contacts. - Splitting the arc – The resistance of the arc can be increased by splitting the arc into a number of smaller arcs in series. Each one of these arcs experiences the effect of lengthening and cooling. The arc may be split by introducing some conducting plates between the contacts. 2. Low Resistance or Current zero Method - (a) causing the ionised particles in the space between contacts to recombine into neutral molecules. - (b) sweeping the ionised particles away and replacing them by unionised particles. Therefore, the real problem in AC arc interruption is to rapidly deionise the medium between contacts as soon as the current becomes zero so that the rising contact voltage or restriking voltage cannot breakdown the space between contacts. The de-ionisation of the medium can be achieved by : - (i) lengthening of the gap : The dielectric strength of the medium is proportional to the length of the gap between contacts. Therefore, by opening the contacts rapidly, higher dielectric strength of the medium can be achieved. - (ii) high pressure. If the pressure in the vicinity of the arc, is increased, the density of the particles constituting the’ discharge also increases. The increased density of particles causes higher rate of de-ionisation and consequently the dielectric strength of the medium between contacts is increased. - (iii) cooling : Natural combination of ionised particles takes place more rapidly if they are allowed to cool. Therefore, dielectric strength of the medium between the contacts can be increased by cooling the arc - (iv) blast effect : If the ionised particles between the contacts are swept away and replaced by un-ionised particles, the dielectric strength of the medium can be increased consider-ably. This may be achieved by a gas blast directed along the discharge or by forcing oil into the contact space.
Directions: Examine the nutrition label of the food you have chosen. Based on the information on the label, your book, and your knowledge of biology, answer the following questions. - What is your food? Honey Nut Cheerios. - What are the nutrients your body needs in the greatest amounts? Macronutrients, such as fat, water, carbs, protein. - What nutrients are essential but required in small amounts? Micronutrients, such as nitrogen and potassium. - What nutrients are intended to be consumed at a lower level than the daily allowance? Certain vitamins, cholesterol, fats - Why are they required in lower amounts? Are they required at all? And if so for what? Because our bodies already make a sufficient amount of these things. We do need vitamins, but most of them our bodies will already produce, like vitamin D. - Which organic compounds in your food item provide you with energy? Carbohydrates, sodium, and some protein. - Below is a table showing the amount of calories burned per hour playing competitive soccer by people who weigh 130, 155 and 190 pounds. \|Activity\|\|130 lbs\|\|155 lbs\|\|190 lbs\| \|Competitive Soccer\|\|295 Calories per Hour\|\|352 Calories per Hour\|\|431 Calories per Hour\| Based on the information above, how long (what percent of an hour) could two servings of your food power you to play competitive soccer? To do this, divide the number of calories in 2 servings of your food by the number of calories burned per hour for someone with your weight. Use the information that is closest to your weight. Show your work. - Is your food good for your heart? In your explanation, consider if your food is high in saturated fats and cholesterol. In general, less than 5% of your daily value is low and more than 20% is high. See if you can determine other factors in this food that make it heart healthy or not. My food is good for you. Cheerios have no cholesterol - Name three roles that lipids, such as fats and cholesterol, play in our bodies. (lipids are fats, oils, waxes, and cholesterol) does your food provide lipids? Three roles lipids play are chemical messengers, they store energy and they help maintain our body temperature. - There are different categories of fats: saturated, unsaturated, and Trans. Differentiate between these types of fats. Explain how the body uses them and which are the most healthful and why. - Should fats be limited? Why or why not? - Although sugar is a good source of energy for your body, the excess sugar in our bodies can cause weight gain. When we have high amounts of sugar in our blood, our bodies have a ready source of energy and don’t need to burn fat for energy. The fat in our food is then stored in our bodies. Doctors recommend that we intake no more than 40 grams of sugar a day to maintain healthy blood sugar levels. The WHO recommends 20g. Based on this, do you believe your food item is high in sugar? Explain your reasoning. - What is the main role that carbohydrates serve in our bodies? What happens when we over consume carbohydrates? Explain why. - Fiber, the indigestible cell walls of plant materials, helps your food move more easily through your digestive tract. You need about 25 g of fiber daily. If you ate two servings of your food item, what percent of your daily fiber intake did you receive? Explain your reasoning. - Many people do not get enough fiber in their diet. What types of foods could you eat to increase your fiber intake? - Determine how much protein you need in a day. To do this, you multiply 0.36 times your bodyweight in pounds. Based on this, is your food a good source of protein for you? Explain your reasoning. In general remember, less than 5% of your daily value is low and more than 20% is high. - Name three roles that proteins play in our bodies. - What are the building blocks of proteins? Where do we get these building blocks? - Explain how a turkey protein can become a human muscle protein. - What do you think is the best advice for someone looking to lose weight? What kind of diet plan would be the most useful? (Chapter 15a) - Is your food a good source of the 4 vitamins listed above? Explain your reasoning. The body needs a small amount of sodium to help maintain normal blood pressure and normal function of muscles and nerves. Sodium intake is recommended to be less than 3,000 milligrams daily. Too much sodium in your diet can result in water retention and bloating and increased blood pressure. - Is your food high in sodium? Explain your reasoning. In general remember, less than 5% of your daily value is low and more than 20% is high. - What nutrient in important in your body, but has not been discussed as part of this activity? Why is this nutrient so important? - What is your evaluation of your food? Is it healthy? Unhealthy? Marginal? Neutral? Be specific in your analysis. Would you recommend that other people consume it? Would you feed it to a child? Explain all your reasoning.
Thermal conductivity measurement Thermal conductivity is a material property. It expresses how well a material conducts heat under steady state conditions. In dynamic situations also the heat capacity enters the equations. In case of a finite object, for example an insulation panel, we may also consider the total thermal resistance of the object. In many cases we may assume that materials are isotropic, so that the thermal conductivity of a material can be expressed as a single number. However, some materials are non-isotropic, so that thermal conductivity is a 3-dimensional property. Thermal conductivity measurements are used for many proposes. The main ones are: - establishing material properties - quality assurance of insulation materials What is measured The measured quantity is thermal conductivity in W/(m·K). Most systems actually measure a thermal resistance and in some cases, when studying a non-homogeneous insulation panel, it is actually the average thermal conductivity over thickness that is determined. In some cases you may also wish to know the thermal conductivity as a function of temperature or pressure. The general principle of a thermal conductivity measurement is that you must: - inject a known amount of heat - measure a temperature difference in time or over a known distance - while making sure that you take into account phase transitions, non-isotropy, pressure, absolute temperature, expansion, etc. For thermal conductivity measurement there is no single measurement solution. The main issues are: - different materials have very different thermal conductivities, from air to aluminium the difference is a factor 10 000 - specimen size is often non-ideal - fluids and gasses may start flowing by thermal convection - moist materials may locally dry out ad be no longer representative - compressible materials may have properties depending on the pressure they experience - the nature of the material may pose a problem; common issues are non-isotropy, thermally induced flow (for fluids and gas), evaporation of moisture - contact resistance between specimen and temperature sensors may be a major source of error There are several main technologies used: - steady state techniques, typically relying on a constant heat flux and measuring a temperature difference after a transient interval. - transient techniques, typically relying on a constant power and analysing the temperature difference between the start of heating and the temperature at later moments Examples of Steady state techniques are guarded hot plates, heat flux meter apparatus, thin heater apparatus. Examples of transient techniques are thermal needles and hot disks. Selecting a sensor or measuring system a typical checklist is: - what is the material type, (metal, fluid, insulation material) and expected thermal conductivity range - what are the available specimen dimensions - what is the temperature range over which a measurement must be made - what are the accuracy requirements - what other things must be measured, such as density, heat capacity - is any compliance to standards required What we contribute Hukseflux has been designing thermal conductivity measurement sensors and systems for over 20 years. In the course of the years, we have added many sensors to our product range. We also offer measuring services. - sell our “standard” product range of sensors and systems for material characterisation, mainly aimed at plastics, composites and soils. See the thermal conductivity measurement selection guide - perform “standard” measurements in our material characterisation laboratory on specimens supplied by customers. Common materials are plastics, paints, composites, pastes, powders, fluids, foodstuff and insulation materials. Please ask for our specimen requirements and fill in our request form - design customer-specific experiments together with our customers to analyse material- or equipment properties and thermal contact resistances, as part of our engineering and consultancy services - provide expert training in system use, in particular for thermal analyses of soils, thermal route surveys and for measurements of building envelope thermal resistance - rent out systems, including support for analysing data. The materials we most often analyse are: - soils, sediments, concretes, cements - measured with thermal needles and systems of the TP series - pastes, sludge’s, fluids - measured with needles and systems of the TP series - plastics and composites - measured with THASYS and THISYS measuring systems, often in multiple directions - thin foil materials, plastic foils, paints - measured with THASYS - thin metal graphite, graphene foils - measured with THISYS - fluids - measured with our thermal needles and special hot wires - walls – measured with HFP01 and TRSYS Our systems are optimised for the demands of different applications. We distinguish: - specimen material type and specimen dimensions - temperature range - direction of measurement - in case of non-isotropic materials you may measure in 2 directions - heating power - in case of use in soils and fluids The measurement uncertainty of thermal conductivity measurements depends on many factors. For example the nature of the material, the specimen dimensions, the thermal resistance of contact between temperature sensors and specimen. We can assist you making a through uncertainty evaluation. How to request a thermal conductivity measurement service - look at our selection guide - read our specimen requirements document - fill in our request form How to rent a thermal conductivity measuring system - ask for our rental conditions Hukseflux is a leader in thermal conductivity measurement. We offer: - assistance: help you select the best sensor or system for your application - proven performance: in most applications we have experience - worldwide support – specialists available in the major economies - compliance with standards: IEEE, ASTM, ... - good price versus performance; also rental systems - traceability: formal metrological traceability to international standards Take a look at our selection of suitable sensors:
Nitrogen is the most abundant gas-of-life in the atmosphere (78%). It is an essential building block of amino acids present in all proteins. It is a very stable, unreactive gas, but micro-organisms in the soil and some plants are able to extract nitrogen from the atmosphere, making it available to growing plants. Lightning also manages to oxidize some atmospheric nitrogen. Oxygen is the second most abundant gas-of-life in the atmosphere (21%). Every animal absorbs oxygen with every breath, using it to fuel bodily digestion of the foods animals eat. This process builds bodies and provides the energy of muscles. In the great oxygen cycle, plants extract oxygen from carbon dioxide and exhale it to the atmosphere for animals to breathe. Water vapor is the third most abundant gas-of-life in the atmosphere (varies up to 5%). Water vapor is part of the great water cycle, where water is evaporated into the atmosphere from salty seas, surface water, and plants. Rain and snow return it to the surface supply of fresh water. No animals, plants, or sea creatures could exist without water. Water vapor is the most effective “greenhouse gas” in the atmosphere, with far more effect than carbon dioxide. It reduces incoming solar radiation by day and reduces surface cooling at night. Water is also a global temperature stabilizer – heat is transferred from oceans and land as latent heat by evaporation, forming clouds that often cool the surface. Finally, carbon dioxide is the least abundant gas-of-life in the atmosphere (0.04%) – just a trace, but a vitally important trace. No plants could exist on Earth without carbon dioxide, and no animals could exist without plants. Plants extract carbon dioxide from the atmosphere to form proteins, sugars, and carbohydrates, and animals add essential minerals to turn these into protein, fat, sinews, and bones. The carbon from carbon dioxide is the building block for all life on Earth, for every bit of organic material, and for every carbon fuel – oil, gas, and coal. Carbon dioxide is a “greenhouse gas” that tends to retain some surface warmth, but there is no evidence in ancient or modern temperature records to suggest that carbon dioxide is a dominant factor controlling global temperature. None of these natural gases is toxic to life under any feasible atmospheric conditions, but all can be toxic above certain levels. For carbon dioxide, toxic effects on humans don’t even begin until it is fifty times the present atmospheric level – our exhaled breath is 100 times current levels in the atmosphere. No thinking person could class any of these gases as an atmospheric pollutant – they are all naturally occurring, non-toxic, essential gases of life. Together they make up 95% of the human body, which is effectively 68% carbon dioxide. So if carbon dioxide is a pollutant, the human body is badly polluted. Page Printed from: http://www.americanthinker.com/blog/2014/08/the_gases_of_life_are_not_pollutants.html at August 12, 2014 - 06:51:24 AM CDT
Table of Contents : Top Suggestions Worksheet On Articles For Grade 2 : Worksheet On Articles For Grade 2 Fill in the blanks with the correct consonant blend in this spelling worksheet created for first grade students and other young learners this activity highlights beginning blends in words like Can your child use his fifth grade math skills to calculate commission sure to spruce up his multiplication ability and familiarity with decimals this worksheet gives him a page full of word Remote learning started in earnest on april 6th for shemar that meant just four hours per week of live online. 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Mountain gorillas, which are listed as endangered by the International Union for Conservation of Nature, are seeing their population numbers rise. Uncontrolled hunting, disease, conflicts, and habitat loss put the species in danger, but there are encouraging signs that mountain gorillas are thriving. According to a new survey conducted by the Protected Area Authorities in Uganda and the Democratic Republic of the Congo, the mountain gorilla population has now risen to a total of 1,063. It’s not exactly cause for too much celebration, however, as that number is still relatively low, but it’s an improvement on a previous survey from 2008 that had the number at just 680. In 1978 the total population of mountain gorillas in Virunga Massif was at an all-time low of about 240 individuals. A subspecies of the eastern gorilla, the mountain gorillas survive in two distinct populations. One is confined to Uganda’s Bwindi Impenetrable National Park, and the other is found in the Virunga Massif that stretches across the borders of Rwanda, Uganda, and the Democratic Republic of the Congo. It was in Virunga Massif that Dian Fossey established the now-famous Karisoke Research Center in the 1960s. At the time, mountain gorillas were already heading toward extinction. Matt Walpole, senior director of conservation programs at Fauna & Flora International, said, “These survey results are undoubtedly good news, yet mountain gorillas remain threatened with extinction […] We have to remain vigilant against threats and build on the success achieved to date by ensuring resources — including from tourism — are properly directed to mountain gorillas and local communities.” The rebounding population is largely thanks to the extreme efforts of conservationists, some of whom lost their lives to protect the gorillas and local communities in the Virunga Massif. An increasing number of veterinarians are caring for the animals in the wild, park rangers are working hard to deter poachers, and eco-tourism has benefited local economies and given communities an incentive to keep their gorillas safe.
The Tunguska event was a large explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908 (NS). The explosion over the sparsely populated Eastern Siberian Taiga flattened an estimated 80 million trees over an area of 2,150 km2 (830 sq mi) of forest, and eyewitness reports suggest that at least three people may have died in the event. The explosion is generally attributed to the air burst of a meteoroid. It is classified as an impact event, even though no impact crater has been found; the object is thought to have disintegrated at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than to have hit the surface of the Earth. Due to the remoteness of the site and the limited instrumentation available at the time of the event, modern scientific interpretations of its cause and magnitude have relied chiefly on damage assessments and geological studies conducted many years after the fact. Studies have yielded different estimates of the meteoroid’s size, on the order of 50 to 190 metres (160 to 620 feet), depending on whether the body entered with a low or high speed. It is estimated that the shock wave from the air burst would have measured 5.0 on the Richter magnitude scale, and estimates of its energy have ranged from 3–30 megatons of TNT (13–126 petajoules). An explosion of this magnitude would be capable of destroying a large metropolitan area. Since the 1908 event, there have been an estimated 1,000 scholarly papers (most in Russian) published about the Tunguska explosion. In 2013, a team of researchers published the results of an analysis of micro-samples from a peat bog near the center of the affected area which show fragments that may be of meteoritic origin. The Tunguska event is the largest impact event on Earth in recorded history, though much larger impacts have occurred in prehistoric times. It has been mentioned numerous times in popular culture, and has also inspired real-world discussion of asteroid impact avoidance. On 30 June 1908 (cited in Russia as 17 Jun 1908, Julian Calendar, prior to implementation of the Soviet calendar in 1918), at around 07:17 local time, Evenki natives and Russian settlers in the hills northwest of Lake Baikal observed a column of bluish light, nearly as bright as the Sun, moving across the sky. About ten minutes later, there was a flash and a sound similar to artillery fire. Eyewitnesses closer to the explosion reported that the source of the sound moved from the east to the north of them. The sounds were accompanied by a shock wave that knocked people off their feet and broke windows hundreds of kilometres away. The explosion registered at seismic stations across Eurasia, and air waves from the blast were detected in Germany, Denmark, Croatia, the United Kingdom, and as far away as Batavia and Washington, D.C. It is estimated that, in some places, the resulting shock wave was equivalent to an earthquake measuring 5.0 on the Richter magnitude scale. Over the next few days, night skies in Asia and Europe were aglow, with contemporaneous reports of photographs being successfully taken at midnight in Sweden and Scotland. It has been theorized that this effect was due to light passing through high-altitude ice particles that had formed at extremely low temperatures—a phenomenon that many years later was reproduced by space shuttles. In the United States, a Smithsonian Astrophysical Observatory program at the Mount Wilson Observatory in California observed a months-long decrease in atmospheric transparency consistent with an increase in suspended dust particles. Selected eyewitness reports Though the region of Siberia in which the explosion occurred was extremely sparsely populated in 1908, accounts of the event from eyewitnesses who were in the surrounding area at the time do exist. Regional newspapers also reported the event shortly after it occurred. According to the testimony of S. Semenov, as recorded by Russian mineralogist Leonid Kulik’s expedition in 1930: At breakfast time I was sitting by the house at Vanavara Trading Post [approximately 65 kilometres (40 mi) south of the explosion], facing north. […] I suddenly saw that directly to the north, over Onkoul’s Tunguska Road, the sky split in two and fire appeared high and wide over the forest [as Semenov showed, about 50 degrees up—expedition note]. The split in the sky grew larger, and the entire northern side was covered with fire. At that moment I became so hot that I couldn’t bear it as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few metres. I lost my senses for a moment, but then my wife ran out and led me to the house. After that such noise came, as if rocks were falling or cannons were firing, the Earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it. When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn, a part of the iron lock snapped. Testimony of Chuchan of Shanyagir tribe, as recorded by I. M. Suslov in 1926: We had a hut by the river with my brother Chekaren. We were sleeping. Suddenly we both woke up at the same time. Somebody shoved us. We heard whistling and felt strong wind. Chekaren said, ‘Can you hear all those birds flying overhead?’ We were both in the hut, couldn’t see what was going on outside. Suddenly, I got shoved again, this time so hard I fell into the fire. I got scared. Chekaren got scared too. We started crying out for father, mother, brother, but no one answered. There was noise beyond the hut, we could hear trees falling down. Chekaren and I got out of our sleeping bags and wanted to run out, but then the thunder struck. This was the first thunder. The Earth began to move and rock, the wind hit our hut and knocked it over. My body was pushed down by sticks, but my head was in the clear. Then I saw a wonder: trees were falling, the branches were on fire, it became mighty bright, how can I say this, as if there was a second sun, my eyes were hurting, I even closed them. It was like what the Russians call lightning. And immediately there was a loud thunderclap. This was the second thunder. The morning was sunny, there were no clouds, our Sun was shining brightly as usual, and suddenly there came a second one! Chekaren and I had some difficulty getting out from under the remains of our hut. Then we saw that above, but in a different place, there was another flash, and loud thunder came. This was the third thunder strike. Wind came again, knocked us off our feet, struck the fallen trees. We looked at the fallen trees, watched the tree tops get snapped off, watched the fires. Suddenly Chekaren yelled “Look up” and pointed with his hand. I looked there and saw another flash, and it made another thunder. But the noise was less than before. This was the fourth strike, like normal thunder. Now I remember well there was also one more thunder strike, but it was small, and somewhere far away, where the Sun goes to sleep. Sibir newspaper, 2 July 1908: On the morning of 17th of June, around 9:00, we observed an unusual natural occurrence. In the north Karelinski village [200 verst (213 km (132 mi)) north of Kirensk] the peasants saw to the northwest, rather high above the horizon, some strangely bright (impossible to look at) bluish-white heavenly body, which for 10 minutes moved downwards. The body appeared as a “pipe”, i.e., a cylinder. The sky was cloudless, only a small dark cloud was observed in the general direction of the bright body. It was hot and dry. As the body neared the ground (forest), the bright body seemed to smudge, and then turned into a giant billow of black smoke, and a loud knocking (not thunder) was heard as if large stones were falling, or artillery was fired. All buildings shook. At the same time the cloud began emitting flames of uncertain shapes. All villagers were stricken with panic and took to the streets, women cried, thinking it was the end of the world. The author of these lines was meantime in the forest about 6 versts [6.4 km] north of Kirensk and heard to the north east some kind of artillery barrage, that repeated in intervals of 15 minutes at least 10 times. In Kirensk in a few buildings in the walls facing north-east window glass shook. Siberian Life newspaper, 27 July 1908: When the meteorite fell, strong tremors in the ground were observed, and near the Lovat village of the Kansk uezd two strong explosions were heard, as if from large-calibre artillery. Krasnoyaretz newspaper, 13 July 1908: Kezhemskoe village. On the 17th an unusual atmospheric event was observed. At 7:43 the noise akin to a strong wind was heard. Immediately afterward a horrific thump sounded, followed by an earthquake that literally shook the buildings as if they were hit by a large log or a heavy rock. The first thump was followed by a second, and then a third. Then the interval between the first and the third thumps was accompanied by an unusual underground rattle, similar to a railway upon which dozens of trains are travelling at the same time. Afterward, for 5 to 6 minutes an exact likeness of artillery fire was heard: 50 to 60 salvoes in short, equal intervals, which got progressively weaker. After 1.5–2 minutes after one of the “barrages” six more thumps were heard, like cannon firing, but individual, loud and accompanied by tremors. The sky, at the first sight, appeared to be clear. There was no wind and no clouds. Upon closer inspection to the north, i.e. where most of the thumps were heard, a kind of an ashen cloud was seen near the horizon, which kept getting smaller and more transparent and possibly by around 2–3 p.m. completely disappeared. In January 2020, new information regarding eyewitness accounts has been published. It was not until more than a decade after the event that any scientific analysis of the region took place, in part due to the isolation of the area. In 1921, the Russian mineralogist Leonid Kulik led a team to the Podkamennaya Tunguska River basin to conduct a survey for the Soviet Academy of Sciences. Although they never visited the central blast area, the many local accounts of the event led Kulik to believe that the explosion had been caused by a giant meteorite impact. Upon returning, he persuaded the Soviet government to fund an expedition to the suspected impact zone, based on the prospect of salvaging meteoric iron. Kulik led a scientific expedition to the Tunguska blast site in 1927. He hired local Evenki hunters to guide his team to the centre of the blast area, where they expected to find an impact crater. To their surprise, there was no crater to be found at ground zero. Instead they found a zone, roughly 8 kilometres (5.0 mi) across, where the trees were scorched and devoid of branches, but still standing upright. Trees more distant from the center had been partly scorched and knocked down in a direction away from the center, creating a large radial pattern of downed trees. In the 1960s, it was established that the zone of leveled forest occupied an area of 2,150 km2 (830 sq mi), its shape resembling a gigantic spread-eagled butterfly with a “wingspan” of 70 km (43 mi) and a “body length” of 55 km (34 mi). Upon closer examination, Kulik located holes that he erroneously concluded were meteorite holes; he did not have the means at that time to excavate the holes. During the following 10 years, there were three more expeditions to the area. Kulik found several dozens of little “pothole” bogs, each 10 to 50 metres (33 to 164 feet) in diameter, that he thought might be meteoric craters. After a laborious exercise in draining one of these bogs (the so-called “Suslov’s crater”, 32 m (105 ft) in diameter), he found an old tree stump on the bottom, ruling out the possibility that it was a meteoric crater. In 1938, Kulik arranged for an aerial photographic survey of the area covering the central part of the leveled forest (250 square kilometres (97 sq mi)). The original negatives of these aerial photographs (1,500 negatives, each 18 by 18 centimetres (7.1 by 7.1 inches)) were burned in 1975 by order of Yevgeny Krinov, then Chairman of the Committee on Meteorites of the USSR Academy of Sciences, as part of an initiative to dispose of hazardous nitrate film. Positive prints were preserved for further study in the Russian city of Tomsk. Expeditions sent to the area in the 1950s and 1960s found microscopic silicate and magnetite spheres in siftings of the soil. Similar spheres were predicted to exist in the felled trees, although they could not be detected by contemporary means. Later expeditions did identify such spheres in the resin of the trees. Chemical analysis showed that the spheres contained high proportions of nickel relative to iron, which is also found in meteorites, leading to the conclusion they were of extraterrestrial origin. The concentration of the spheres in different regions of the soil was also found to be consistent with the expected distribution of debris from a meteoroid air burst. Later studies of the spheres found unusual ratios of numerous other metals relative to the surrounding environment, which was taken as further evidence of their extraterrestrial origin. Chemical analysis of peat bogs from the area also revealed numerous anomalies considered consistent with an impact event. The isotopic signatures of carbon, hydrogen, and nitrogen at the layer of the bogs corresponding to 1908 were found to be inconsistent with the isotopic ratios measured in the adjacent layers, and this abnormality was not found in bogs located outside the area. The region of the bogs showing these anomalous signatures also contains an unusually high proportion of iridium, similar to the iridium layer found in the Cretaceous–Paleogene boundary. These unusual proportions are believed to result from debris from the falling body that deposited in the bogs. The nitrogen is believed to have been deposited as acid rain, a suspected fallout from the explosion. Researcher John Anfinogenov has suggested that a boulder found at the event site, known as John’s stone, is a remnant of the meteorite, but oxygen isotope analysis of the quartzite suggests that it is of hydrothermal origin, and probably related to Permian-Triassic Siberian Traps magmatism. Earth impactor model The leading scientific explanation for the explosion is the air burst of an asteroid 6–10 km (4–6 mi) above the Earth’s surface. Meteoroids enter Earth’s atmosphere from outer space every day, travelling at a speed of at least 11 km/s (7 mi/s). The heat generated by compression of air in front of the body (ram pressure) as it travels through the atmosphere is immense and most meteoroids burn up or explode before they reach the ground. Early estimates of the energy of the Tunguska air burst ranged from 10–15 megatons of TNT (42–63 petajoules) to 30 megatons of TNT (130 PJ), depending on the exact height of the burst as estimated when the scaling laws from the effects of nuclear weapons are employed. More recent calculations that include the effect of the object’s momentum find that more of the energy was focused downward than would be the case from a nuclear explosion and estimate that the air burst had an energy range from 3 to 5 megatons of TNT (13 to 21 PJ). The 15-megaton (Mt) estimate represents an energy about 1,000 times greater than that of the atomic bomb dropped on Hiroshima, Japan, in 1945, and roughly equal to that of the United States’ Castle Bravo nuclear test in 1954 (which measured 15.2 Mt) and one-third that of the Soviet Union’s Tsar Bomba test in 1961. A 2019 paper suggests the explosive power of the Tunguska event may have been around 20–30 megatons. Since the second half of the 20th century, close monitoring of Earth’s atmosphere through infrasound and satellite observation has shown that asteroid air bursts with energies comparable to those of nuclear weapons routinely occur, although Tunguska-sized events, on the order of 5–15 megatons, are much rarer. Eugene Shoemaker estimated that 20-kiloton events occur annually and that Tunguska-sized events occur about once every 300 years. More recent estimates place Tunguska-sized events at about once every thousand years, with 5-kiloton air bursts averaging about once per year. Most of these air bursts are thought to be caused by asteroid impactors, as opposed to mechanically weaker cometary materials, based on their typical penetration depths into the Earth’s atmosphere. The largest asteroid air burst to be observed with modern instrumentation was the 500-kiloton Chelyabinsk meteor in 2013, which shattered windows and produced meteorites. The explosion’s effect on the trees near the hypocentre of the explosion was similar to the effects of the conventional Operation Blowdown. These effects are caused by the blast wave produced by large air burst explosions. The trees directly below the explosion are stripped as the blast wave moves vertically downward, but remain standing upright, while trees farther away are knocked over because the blast wave is travelling closer to horizontal when it reaches them. Soviet experiments performed in the mid-1960s, with model forests (made of matches on wire stakes) and small explosive charges slid downward on wires, produced butterfly-shaped blast patterns similar to the pattern found at the Tunguska site. The experiments suggested that the object had approached at an angle of roughly 30 degrees from the ground and 115 degrees from north and had exploded in mid-air. Asteroid or comet? In 1930, the British astronomer F. J. W. Whipple suggested that the Tunguska body was a small comet. A comet is composed of dust and volatiles, such as water ice and frozen gases, and could have been completely vaporised by the impact with Earth’s atmosphere, leaving no obvious traces. The comet hypothesis was further supported by the glowing skies (or “skyglows” or “bright nights”) observed across Eurasia for several evenings after the impact, which are possibly explained by dust and ice that had been dispersed from the comet’s tail across the upper atmosphere. The cometary hypothesis gained a general acceptance among Soviet Tunguska investigators by the 1960s. In 1978, Slovak astronomer Ľubor Kresák suggested that the body was a fragment of Comet Encke. This is a periodic comet with an extremely short period of three years that stays entirely within the orbit of Jupiter. It is also responsible for the Beta Taurids, an annual meteor shower with a maximum activity around 28–29 June. The Tunguska event coincided with the peak activity of that shower, and the approximate trajectory of the Tunguska object is consistent with what would be expected from a fragment of Comet Encke. It is now known that bodies of this kind explode at frequent intervals tens to hundreds of kilometres above the ground. Military satellites have been observing these explosions for decades. During 2019 astronomers searched for hypothesized asteroids ~100 metres in diameter from the Taurid swarm between 5–11 July, and 21 July – 10 August. However, as of December 2019, there have been no reports of discoveries of any such objects. In 1983, astronomer Zdeněk Sekanina published a paper criticising the comet hypothesis. He pointed out that a body composed of cometary material, travelling through the atmosphere along such a shallow trajectory, ought to have disintegrated, whereas the Tunguska body apparently remained intact into the lower atmosphere. Sekanina argued that the evidence pointed to a dense, rocky object, probably of asteroidal origin. This hypothesis was further boosted in 2001, when Farinella, Foschini, et al. released a study calculating the probabilities based on orbital modelling extracted from the atmospheric trajectories of the Tunguska object. They concluded with a probability of 83% that the object moved on an asteroidal path originating from the asteroid belt, rather than on a cometary one (probability of 17%). Proponents of the comet hypothesis have suggested that the object was an extinct comet with a stony mantle that allowed it to penetrate the atmosphere. The chief difficulty in the asteroid hypothesis is that a stony object should have produced a large crater where it struck the ground, but no such crater has been found. It has been hypothesised that the passage of the asteroid through the atmosphere caused pressures and temperatures to build up to a point where the asteroid abruptly disintegrated in a huge explosion. The destruction would have to have been so complete that no remnants of substantial size survived, and the material scattered into the upper atmosphere during the explosion would have caused the skyglows. Models published in 1993 suggested that the stony body would have been about 60 metres (200 ft) across, with physical properties somewhere between an ordinary chondrite and a carbonaceous chondrite. Typical carbonaceous chondrite substance tends to be dissolved with water rather quickly unless it is frozen. Christopher Chyba and others have proposed a process whereby a stony meteorite could have exhibited the behaviour of the Tunguska impactor. Their models show that when the forces opposing a body’s descent become greater than the cohesive force holding it together, it blows apart, releasing nearly all of its energy at once. The result is no crater, with damage distributed over a fairly wide radius, and all of the damage resulting from the thermal energy released in the blast. Three-dimensional numerical modelling of the Tunguska impact done by Utyuzhnikov and Rudenko in 2008 supports the comet hypothesis. According to their results, the comet matter dispersed in the atmosphere, while the destruction of the forest was caused by the shock wave. During the 1990s, Italian researchers, coordinated by the physicist Giuseppe Longo from the University of Bologna, extracted resin from the core of the trees in the area of impact to examine trapped particles that were present during the 1908 event. They found high levels of material commonly found in rocky asteroids and rarely found in comets. Kelly et al. (2009) contend that the impact was caused by a comet because of the sightings of noctilucent clouds following the impact, a phenomenon caused by massive amounts of water vapor in the upper atmosphere. They compared the noctilucent cloud phenomenon to the exhaust plume from NASA’s Endeavour space shuttle. In 2013, analysis of fragments from the Tunguska site by a joint US-European team was consistent with an iron meteorite. The February 2013 Chelyabinsk bolide event provided ample data for scientists to create new models for the Tunguska event. Researchers used data from both Tunguska and Chelyabinsk to perform a statistical study of over 50 million combinations of bolide and entry properties that could produce Tunguska-scale damage when breaking apart or exploding at similar altitudes. Some models focused on combinations of properties which created scenarios with similar effects to the tree fall pattern as well as the atmospheric and seismic pressure waves of Tunguska. Four different computer models produced similar results; they concluded that the likeliest candidate for the Tunguska impactor was a stony body between 50 and 80 m (164 and 262 ft) in diameter, entering the atmosphere at roughly 55,000 km/h (34,000 mph), exploding at 10 to 14 km (6 to 9 mi) altitude, and releasing explosive energy equivalent to between 10 and 30 megatons. This is similar to the blast energy equivalent of the 1980 volcanic eruption of Mount St. Helens. The researchers also concluded impactors of this size only hit the Earth at an average interval scale of millennia. In June 2007, scientists from the University of Bologna identified a lake in the Tunguska region as a possible impact crater from the event. They do not dispute that the Tunguska body exploded in mid-air but believe that a 10-metre (33 ft) fragment survived the explosion and struck the ground. Lake Cheko is a small, bowl-shaped lake approximately 8 km (5.0 mi) north-northwest of the hypocentre. The hypothesis has been disputed by other impact crater specialists. A 1961 investigation had dismissed a modern origin of Lake Cheko, saying that the presence of metres-thick silt deposits at the lake’s bed suggests an age of at least 5,000 years, but more recent research suggests that only a metre or so of the sediment layer on the lake bed is “normal lacustrine sedimentation”, a depth consistent with an age of about 100 years. Acoustic-echo soundings of the lake floor provide support for the hypothesis that the lake was formed by the Tunguska event. The soundings revealed a conical shape for the lake bed, which is consistent with an impact crater. Magnetic readings indicate a possible metre-sized chunk of rock below the lake’s deepest point that may be a fragment of the colliding body. Finally, the lake’s long axis points to the hypocentre of the Tunguska explosion, about 7.0 km (4.3 mi) away. Work is still being done at Lake Cheko to determine its origins. The main points of the study are that: Cheko, a small lake located in Siberia close to the epicentre of the 1908 Tunguska explosion, might fill a crater left by the impact of a fragment of a cosmic body. Sediment cores from the lake’s bottom were studied to support or reject this hypothesis. A 175-centimetre-long (69 in) core, collected near the center of the lake, consists of an upper c. 1-metre-thick (39 in) sequence of lacustrine deposits overlaying coarser chaotic material. 210Pb and 137Cs indicate that the transition from lower to upper sequence occurred close to the time of the Tunguska event. Pollen analysis reveals that remains of aquatic plants are abundant in the top post-1908 sequence but are absent in the lower pre-1908 portion of the core. These results, including organic C, N and δ13C data, suggest that Lake Cheko formed at the time of the Tunguska event. In 2017, new research by Russian scientists pointed to a rejection of the theory that Lake Cheko was created by the Tunguska event. They used soil research to prove that the lake is 280 years old or even much older; in any case clearly older than the Tunguska event. Though scientific consensus is that the Tunguska explosion was caused by the impact of a small asteroid, there are some dissenters. Astrophysicist Wolfgang Kundt has proposed that the Tunguska event was caused by the release and subsequent explosion of 10 million tons of natural gas from within the Earth’s crust. The basic idea is that natural gas leaked out of the crust and then rose to its equal-density height in the atmosphere; from there, it drifted downwind, in a sort of wick, which eventually found an ignition source such as lightning. Once the gas was ignited, the fire streaked along the wick, and then down to the source of the leak in the ground, whereupon there was an explosion. The similar verneshot hypothesis has also been proposed as a possible cause of the Tunguska event. Other research has supported a geophysical mechanism for the event. The Tunguska event is not the only example of an enormous unobserved explosion event. For example, the 1930 Curuçá River event in Brazil may have been an explosion of a superbolide that left no clear evidence of an impact crater. Modern developments in infrasound detection by the Comprehensive Nuclear-Test-Ban Treaty Organization and infrared DSP satellite technology have reduced the likelihood of undetected air bursts. A smaller air burst occurred over a populated area on 15 February 2013, at Chelyabinsk in the Ural district of Russia. The exploding meteoroid was determined to have been an asteroid that measured about 17–20 metres (56–66 ft) across, with an estimated initial mass of 11,000 tonnes and which exploded with an energy release of approximately 500 kilotons. The air burst inflicted over 1,200 injuries, mainly from broken glass falling from windows shattered by its shock wave.
What is Artificial Intelligence? Artificial Intelligence (AI) is a technology for creating smart programs and machines that can solve creative problems and generate new information based on existing knowledge. In fact, artificial intelligence is intended to model human activity, which is considered intellectual. A robot that simply and mechanically chops wood is not endowed with AI. The robot, which has learned to chop firewood by itself, following the example of a person and is getting better at it with every attempt, is powered by AI. If the program simply retrieves values from the database according to certain rules, it is not endowed with AI. If the system after training creates programs, methods and documents, solving certain tasks, it possesses AI. How to create an artificial intelligence system The task of AI powered system involves imitating human thinking patterns.To achieve that objective, it is necessary to create a black box – a program that, in response to a set of input values, produces output values similar to the ones of a real person. And to us, it doesn’t matter what happens in “in its head” (between entry and exit). Artificial intelligence systems are created to solve a specific class of problems.The basis of artificial intelligence – learning, imagination, perception and memory. The first component needed to create artificial intelligence powered system is to develop functions that process information in the cognitive way so that one can “feed” the data to the system. Then we need to add mechanisms that implement the ability to learn. Finally, we require a data warehouse to store the information received in the process of learning. Next, we need to recreate functions responsible for imagination. They will simulate new scenarios and situations using existing data and thus generate new information. The learning process can be both inductive and deductive. In an inductive version of the system, pairs of inputs and outputs, questions and answers, are provided. The system must find the relationship between the data and using these patterns, identify the output data using input knowledge. The deductive approach uses the experience of experts as the basis. It is transferred to the system as a knowledge base. In this case the platform utilizes ready-made rules to assist with finding a solution to the condition aside from data sets. AI applications presently employ both approaches. Systems are usually already trained, but they continue to learn in the process. This continuity is done in order for the application to improve by taking to account special conditions like one’s wishes and preferences, changes in the situation, etc. One can even set the probability of unpredictability to make it more human-like. Why artificial intelligence can perform better than a live person? First of all, AI excels because it has a lower probability of error. Artificial intelligence cannot forget or lose information – it has an absolute memory. t cannot inadvertently ignore factors and dependencies – every AI action has a clear rationale. AI does not fluctuate; conversely, it evaluates probabilities and is inclined in favor of a greater one. Therefore, it can justify every step. Besides, AI has no emotions, so its decision-making is not affected. Artificial intelligence programs “think” a few steps forward and embody enough resources to consider all possible scenarios.Potential options for using artificial intelligence Generally speaking, artificial intelligence can do anything. The main aspect is to form the task correctly and populate it with data. In addition, AI can make unexpected conclusions and discern patterns where, it would seem, there are none. Victoria Liset is strategic business & technology consultant to SMEs. She helps businesses improve their performance by using data more efficiently, and helping them to understand the implications of new technologies such as AI, Machine Learning, Big data, blockchain and IoT.
Children and young people spend a lot of time online, which is completely normal and mostly harmless. But children do also face risks such as cyberbullying or seeing content that's inappropriate. That's why it's important for children and young people to know how to stay safe online. Whether you're unsure about what happens online or are up to speed with new technology, it's important that you talk to your child about staying safe. It may feel daunting, but you don't need to be an expert on the internet. Understanding what children do online and the risks they face will help you keep your child safe online. If you think your child is a victim of cyber-bullying or online harassment, please ask them to tell a teacher. What children do online Young people go online to connect with friends, and make new ones, to browse the internet for information, chat with others and play games. They may: - search for information or content on search engines like Google - share images and watch videos through websites or mobile apps like Instagram, Pinterest, Vine and YouTube - use social networking websites like Facebook and Twitter - write or reply to messages on forums and message boards - play games alone or with others through websites, apps or game consoles - chat with other people through online games, games consoles, webcams, social networks and tools like Whatsapp When online, children and young people can learn new things, get help with homework, express themselves creatively and connect with friends and family. There are also risks, but by understanding and talking about the dangers you can help keep your child safe online. The risks and dangers online - Accessing inappropriate content, including pornography - Ignoring age restrictions - Friending or communicating with people they don't know - Grooming and sexual abuse - Sharing personal information - Gambling or running up debts Tips to keep children safe The internet does pose certain risks and dangers to children, but it offers lots of opportunities too. There are things you can do to keep your child safe. Talking to your child is one of the best ways to keep them safe. You can also use parental controls on social networks, online games and browsers or software that can filter or monitor what your child can see. Preventing your children from using the internet or mobile phones won't keep them safe online, so it's important to have conversations that help your child understand how to stay safe and what to do if they ever feel scared or uncomfortable. Inform them that they should never share personal information on social networking profile or 'About me' settings. A telephone number or address innocently entered can easily get into the wrong hands. If they are using video, be sure that you know who they are talking to, and that they are not being asked to undress. If computers and devices are in bedrooms, keep the doors open. What we do in school Whilst regulation and technical solutions are very important, this must be balanced by educating students to take a responsible approach as recommended by Ofsted. The education of students in e-safety is therefore an essential part of the curriculum. We recognise that children and young people need the help and support of the school to recognise and avoid e-safety risks and build their resilience. We use Smoothwall web filtering. The school has a planned e-safety curriculum including: - A 8 week project in Year 7 focussed on cyber-bullying. - A talk on E-Safety is delivered to all new parents as part of a year 7 focus evening. - Year 8 revist e-safety in the context of another project. - Key e-safety messages are reinforced in assemblies to all year groups. - Students are taught in all relevant lessons to be critically aware of the materials/content they access on-line and be guided to validate the accuracy of information as appropriate. - Where students are allowed to freely search the internet, teachers are vigilant in monitoring the content of the websites the students visit; reporting any inappropriate sites found to IT Support. - All students and parents are asked to positively sign an acceptable usage policy prior to using our IT systems. It is accepted that from time to time, for good educational reasons, students may need to research topics (eg racism, drugs, discrimination) that would normally result in internet searches being blocked. In such a situation, staff can request that IT Support can temporarily remove those sites from the filtered list for the period of study.
Hemp production was vital to the health of early America. Village women and children combing crushed hemp fibers prior to weaving into yarn. (Photo by George Silk/The LIFE Picture Collection/Getty Images) Hemp’s roots run deep throughout American history, but that history is often overlooked. Not only was hemp production allowed during our country’s foundational years, but the first American settlers were legally required to grow it. There was even a four-year shortage in the newly-formed state of Virginia where citizens could earn a prison sentence for failure to meet hemp production quotas. Though hemp was (and still is) considered a cash crop, it was also literally used as legal tender. For 200 years, citizens in newly-formed colonies or states could pay their taxes or settle debts with hemp they grew. There was even an image of a farmer harvesting hemp on the old $10 bill. However, that edition was phased out in 1914. All of this begs the question: how did an incredibly valuable resource that served as the backbone of the British Navy and helped America during World War II become stigmatized? With the first significant effort to legalize hemp making its way through Congress now, there’s never been a better time to ask. In 1607, England established its first permanent colony in North America. The settlement was called Jamestown and now exists in what is known as the present-day state of Virginia. The expedition garnered funding from a British joint-stock corporation called “The London Company,” which aimed to recover gold and silver from the Americas after witnessing Spain’s successful ventures in the New World. The expedition went poorly, and their efforts were initially unsuccessful, resulting in famine, death, and even cannibalism. However, settlers discovered plants in that area. Among those plants was a sweeter strain of tobacco, which gave the settlers incentive to continue their efforts in the Americas. They also discovered “Indian hemp,” which was deemed far superior in quality and durability to that of Britain’s. As the demands of the settlement grew, so did its legislation and in 1619, the Americas saw its first hemp production law. The First General Assembly of Virginia, which was the first committee to create legislation, implemented agricultural duties among its citizens. Though the law primarily concerned sowing silk flax seeds, it stated that citizens were required to “plant and dress 100 plants which being found a commodity,” and that “whosoever do fail in the performance of this shall be subject to the punishment of the Governor and Council of Estate.” The law continued, stating that “hemp also, both English and Indian” was to be sown and that “all householders of this colony, that have any of those seeds, to make trial thereof the next season.” The Puritans, who would arrive shortly after in 1620 sowed hemp seeds in New England. It was said that the Mayflower, the ship that brought them over, used British hemp as well. Slaves eventually took over the grueling and laborious efforts of hemp production, among other forms of forced servitude. Since Great Britain is an island, it depended heavily on its naval forces for importation, exportation, and colonization efforts. Its naval forces relied heavily on hemp for sails, cordage, and caulking. The American colonies initially provided large quantities of hemp to Britain until the American Revolution. Hemp production then played a crucial role in American liberation from Great Britain as it helped the nation flourish economically. Washington, Adams, Jefferson, and Franklin, among other founding fathers, were all noted for overseeing hemp production on their plantations as well. Once the colonies united and gained independence from Britain, hemp production grew as quickly as the new nation did. Hemp became increasingly valuable as it gained more uses in medicine, animal feed, paper, and clothing. American hemp production would eventually halt under the Marihuana Tax Act of 1937, but the ban was lifted momentarily due to America’s involvement in World War II, which saw a rise in the demand for hemp. Hemp was necessary for the creation of ropes for porting, thread for the shoes for soldiers, webbing for parachutes, among many other uses, as explained in a film created by the United States Government titled Hemp for Victory. Since hemp and marijuana are both subspecies of the cannabis plant, hemp is often considered to be the same as marijuana, even though it’s nearly impossible to obtain a psychoactive high from hemp ingestion. The Marihuana Tax Act of 1937 lumped hemp in with marijuana. The bill did not explicitly ban hemp production but it implemented an extremely high tax on it and jailed anyone incapable of paying it. The taxation made it impossible for people to continue producing the crop, leading to its decline before and after World War II. Other factors contributed to the end of American hemp production. William Randolph Hearst, a newspaper tycoon, believed hemp production served as a threat to his empire, the foundation of which was built on investments in the lumber industry. He thought this would affect his printing business and was noted for encouraging the spread of yellow journalism about hemp production. Another reason for the hemp production ban was Harry J. Anslinger. Anslinger was the head of the newly-formed Federal Bureau of Narcotics, which backed the Marihuana Tax Act of 1937. Propaganda films like Reefer Madness didn’t help either. The most notable reason for the hemp production ban lies was the prohibition of cannabis, which was used as a tool to enforce racial discrimination, making it easy to prosecute persons of color or persons deemed lower class. This problematic history was even recounted earlier this year during a lawsuit against the federal government to end cannabis prohibition. It seems unlikely that the federal government will legalize cannabis under the current administration, but there are a number of bills moving through Congress now which slowly chip away at it. Hemp production, in particular, is seen as one of the most promising efforts as it’s backed by Senate Majority Leader Mitch McConnell, who is educating fellow lawmakers on the difference between hemp and cannabis. Hemp continues to have endless potential as a commodity for everything from skincare products to sustainable building materials. A recent analysis by the U.S. Senate projected that if hemp is legalized it could bring in $570 million dollars per year. The Senate and House now have to reconcile different versions of the bill for hemp legalization before it can be sent to the president’s desk.
The Physical World The Personalized Nutrition Project Weizmann Scientists Can Use Data about How the Body Responds to Specific Foods to Create a Diet Tailored to You The food we eat affects our health and well-being – but how? One of the key ways is by changing our glucose levels. Glucose, commonly known as blood sugar, is the primary source of energy for the cells that make up our muscles and other tissues. In people who are overweight or obese, high blood sugar levels can cause a rise in insulin levels, leading to fat storage. High blood sugar levels are also associated with a number of serious health problems, such as diabetes, heart disease, stroke, and cancer. However, people have different metabolic responses to the same or similar foods. For example, two teaspoons of sugar in your morning coffee could mean the same thing in metabolic terms – fat storage – as one teaspoon of sugar for your officemate. That's why a diet won't necessarily provide the same results for everyone who tries it, even if they are eating the same foods and exercising the same amount. Recent theories suggest that this variability across individuals may be explained, in part, by differences in their absorption and processing of different types of simple sugars. This absorption takes place mostly in the small intestine, thanks to the hard work of a vast array of microbes – a group collectively referred to as microbiota. At the Weizmann Institute of Science, Prof. Eran Segal of the Department of Computer Science and Applied Mathematics and the Department of Molecular Cell Biology and Dr. Eran Elinav of the Department of Immunology are launching a project that is expected to provide many insights about the function of the microbiota and their role in glucose absorption on a personal level. In the experiment, over the course of ten days, the scientists are monitoring the glucose intake and absorption of hundreds of subjects and the activity of their microbiota. They are collecting data using several methods, including a glucometer that is attached to the subjects' bodies. Subjects can see their own blood sugar levels rise and fall throughout the day in reaction to the foods they eat. Using that data, the scientists will develop algorithms to predict individuals' personal response to a wide variety of foods. Subjects will receive access to a web site with these predictions, a profile of their own gut microbes, an analysis of how the microbes affect blood sugar, and a nutritionally balanced diet tailored just for them. Prof. Segal and Dr. Elinav each bring unique expertise to the study, known as the Personalized Nutrition Project. Prof. Segal, a mathematician and cell biologist, develops computational models aimed at understanding how molecular components interact to carry out complex biological functions. An immunologist and an MD, Dr. Elinav is focused on understanding inflammatory bowel disease and investigates the microbes of the gut. They hope the Personalized Nutrition Project will provide the first-ever comprehensive profile of the small intestine's microbiota, as well as the first tool for predicting individualized glucose response to complex meals. It could pave the way for designing customized, balanced diets based on scientific data about each person's microbial makeup. "If successful, our study may allow us to move from empirically based to personally based nutrition, and thus to personally tailored medicine," says Prof. Segal. For more information about the Personalized Nutrition Project at the Weizmann Institute of Science, go to personalnutrition.org/Home. However, while the site permits users to register, please note that the project is only accepting people who live near the Rehovot, Israel campus, as participants must be physically present. SUPPORT INNOVATIVE SCIENCE Weizmann scientists are finding new ways to fight disease, develop better treatments, and improve quality of life for everyone, everywhere. Your gift will benefit all of humanity.
While more than 90% of elementary schools participate in regularly scheduled recess during the school day, since the mid-2000s, up to 40% of school districts nationwide have reduced or cut recess. As the nation moves to put more emphasis on the importance of standardized test scores and insisting that students need more time during the school day to focus on academics, one critical part of a child’s day is left out: recess. Why is Recess so Critical? Recess is an essential part of a child’s development. The American Academy of Pediatrics says, “Recess serves as a necessary break from the rigors of concentrated, academic challenges in the classroom. But equally important is the fact that safe and well-supervised recess offers cognitive, social, emotional, and physical benefits that may not be fully appreciated when a decision is made to diminish it.” Not only do children need a break during the day from academic work, but physical activity has been shown to improve academic performance. In one study, after 20 minutes of physical activity, students tested better in reading, spelling, and math, were more likely to read above their grade level. They were also less likely to misbehave during class. Students develop social skills on the playground, such as communication skills, including negotiation, cooperation, sharing, and problem solving. They also develop coping skills, such as perseverance and self-control. Physical activity can help to alleviate stress and anxiety and enhance self-esteem of students. Recess Should Not Be withheld as a Form of Punishment Recess is a necessary part of a child’s development and learning. It helps students succeed academically and get their wiggles out during the day, so they can focus better during class time. Therefore, it should follow that withholding recess as a form of punishment is counterproductive to students’ success in school. Yet, a recent Utah Action for Healthy Kids survey found that 43% of all elementary schools in Utah and 52% of Title 1 schools withhold recess as a form of punishment. Recess is the break children need to allow them to be more attentive and more productive in the classroom. When recess is withheld, it does not make them more focused or better behaved, but rather takes away a much-needed break. Get Healthy Utah believes that Utah kids need recess to help them reach the recommended amount of physical activity each day, to improve academic performance, and to help kids to be focused and successful learners.
This computer animation, created using new software called Arepo, simulates 9 billion years of cosmic history. Arepo can accurately follow the birth and evolution of thousands of galaxies over billions of years. Arepo generates the full variety of galaxies seen locally, including majestic spirals like the Milky Way and Andromeda. Credit: CfA/UCSD/HITS/M. Vogelsberger (CfA) & V. Springel (HITS) Astrophysicists have created the most realistic computer simulation of the universe’s evolution to date, tracking activity from the Big Bang to now — a time span of around 14 billion years — in high resolution. Created by a team at the Harvard-Smithsonian Centre for Astrophysics (CfA) in collaboration with researchers at the Heidelberg Institute for Theoretical Studies (HITS), the Arepo software provides detailed imagery of different galaxies in the local universe using a technique known as “moving mesh”. Unlike previous model simulators, such as the Gadget code, Arepo’s hydrodynamic model replicates the gaseous formations following the Big Bang by using a virtual, flexible grid that has the capacity to move to match the motions of the gas, stars, dark matter and dark energy that make up space — it’s like a virtual model of the cosmic web, able to bend and flex to support the matter and celestial bodies that make up the universe. Old simulators instead used a more regimented, fixed, cubic grid. Written By: Liat Clarkcontinue to source article at wired.co.uk
Designed for students in grades K-3, this program contains a teacher's guide with two lesson plans, a video focusing on water conservation and the history of water in Arizona and a student activity book. - Lesson Plan 1 - Kids Can Save Water - Lesson Plan 2 - History of Arizona Water - Download the teacher's guide This short video supports the lessons to reinforce where Arizona's water comes from and how kids can conserve water. Student Activity Book The activity book provides kids with coloring pages, fill in the blank and basic water math activities to complete in class or at home. This program is correlated to Arizona’s College and Career Ready Standards (Common Core) for reading, writing, math, science and social studies.
The peregrine falcon (Falco peregrinus) is a crow-sized, long-winged bird of prey, generally acknowledged to be the swiftest bird (attaining speeds of over 320 km/h). The peregrine falcon (Falco peregrinus) is a crow-sized, long-winged bird of prey, generally acknowledged to be the swiftest bird (attaining speeds of over 320 km/h). The name, which means "wandering", is well suited to this species, represented by 18 races and found breeding on every continent (except Antarctica). Adults are dark blue-grey to blue-black above with dark bars on a salmon to white breast and belly. They have either very dark cheeks or moustachelike markings on the side of the head. Immature birds have brownish plumage with darker, longitudinal stripes on the breast. Both sexes have similar plumages, although males frequently have much paler breasts. Males (tiercels) are about one-third smaller than females (falcons). Normally, 3-5 eggs are laid on a cliff ledge in a slight depression scraped out of earth or gravel by the female. There is little or no nest. Eggs are incubated, mainly by the female, for about 33 days. The male's role is primarily to protect the territory and provide food for the female and young. When young are half grown, the female may help provide food. Young leave the nest at about 5 weeks but remain nearby and depend on parents for food until they can hunt for themselves. Shortly thereafter, the birds leave the nesting area and begin migration. The first year is very difficult for young. Band-recovery information indicates that only about 1 in 4 lives to return to the breeding grounds. Whether peregrines migrate depends on food supply and climatic conditions. The Canadian tundra peregrine (F. peregrinus tundrius) winters as far south as southern South America, whereas the west coast peregrine (F. p. pealei) is essentially nonmigratory. The third race breeding in Canada is the endangered anatum peregrine (F. p. anatum), which bred across Canada wherever adequate food and nesting habitat were available. These birds wintered from the southern US through Central America into northern South America. The peregrine preys almost exclusively on bird species in most parts of its range (coastal and inland cliffs). The anatum peregrine has declined to near extinction in most of its breeding range. The decline is well documented, and studies indicate that the principal cause was reproductive failure resulting from contamination by pesticides (especially DDT), which cause eggshell thinning. The bird has become a symbol of the problems resulting from misuse of the environment. In Canada and the US, specific conservation programs have been very successful, and many young anatum peregrines, bred in captivity, have been successfully released in the wild.
- Took place in 1899-1902. - Many signed up. - 25% of people that signed up were unfit to fight in any war. - Britain struggling to beat unorganised farmers. - With Britain losing to small countries, how did the future of them keeping the Empire look? - The German Army were on the rise. - Britain had to keep up or risk losing colonies. - The British population were in no state to fight a war. - They had fears that they could not defend their colonies against Germany. "The Boer War left many in Britain with doubts about the quality of the working class male" - Potter. America and Germany - By 1908, both America and Germany had overtaken Britain in terms of industrial production. - Germany now had the industry needed to back a full-scale war. - Britain now knew they could not defend themselves against Germany. - Changes had to be made to defend the national security of the nation. - If Britain wanted to support its empire, it needed the industry to back it. - Changes had to made to create an industry large enough to back the empire. "If Britain was to compete and maintain its position as a world power, then it had to be run efficiently" - Murphy The New Liberals - From 1908, the Liberals underwent changes in personnel. - Herbert Asquith - PM. - David Lloyd George - Chancellor. - Winston Churchill - President of the Board of Trade. - They believed they should take more interest in other people's lives. - No laissez-faire. - Without new Liberals and new ideas, there would not have been a push for change. "Liberals underwent a change of emphasis rather than aims" Rowntree and Booth - From 1889-1903. - Seebohm Rowntree investigated poverty in London. - Charles Booth investigated poverty in York. - They both aimed to see how many people were impoverished in their respective cities. - 30% of the population lived below the poverty line. - It was not the people's fault that they were in poverty. The causes were preventable. - This showed that with correct help, many people could be lifted above poverty. "Seebohm Rowntree highlighted unprecedented levels of poverty in different parts of England" - Textbook. - Around 1900, Kier Hardy created the Labour Party. - He was a normal working person who wanted a voice for the working class. - The Liberals would now lose votes if they didn't begin to change thir policies towards the poor. - The liberals raised local taxes in order to build great things. - For example, they used Loch Katrine as a reservoir to provide fresh water for Glasgow. - If these changes benefitted those in a local community and raised living standards, there could have been even greater benefits for the nation as a whole.
Each of NEES's 14 shared laboratory facilities enables researchers to explore a different aspect of the complex way that soils and structures behave as a result of earthquakes and tsunamis. Explore the NEES Laboratories by clicking on the links below. The laboratories fall into five general categories: - Shake Table Labs - Tsunami Wave Basin Labs - Geotechnical Centrifuges Labs - Field Experimentation and Monitoring Labs - Large-scale Laboratory Experimentation Labs Three of the NEES laboratories provide large platforms that can be shaken dynamically by computer-controlled actuators. Test structures, such as scale models of building or bridge components, are built on the table and outfitted with sensors to measure movement and strain. When the table is shaken, it reproduces realistic earthquake ground motions that create strong forces on the test structures. There are three facilities of this type, located at University of Nevada, Reno, University of California, San Diego and University of Buffalo. Oregon State University is home to the NEES Tsunami Wave Basin. This consists of a large, precisely constructed water basin where scale models of shorelines and coastal structures can be positioned. A powerful wave generator can create single waves or varying patterns of repeating waves, allowing investigators to explore the complex effects of tsunamis and storm surge waves on coastlines. Researchers can also use the basin without the wave generator to study how tsunamis are created by underwater landslides or volcanic eruptions. Researchers use a geotechnical centrifuge to study soil-related issues associated with bridge and building foundations, embankments, slopes, shorelines, retaining walls, and tunnels. A small-scale model of a specific site is constructed in a container. For example, this could be a bridge on a hillside next to a river. The container with the model is attached to a large arm that rotates the container at high speeds. As the container is spun around, an increased "gravitational" acceleration is applied (this increase in "gravity" is needed in order to compensate for the reduced scale of the model). Two centrifuge facilities have been developed, one at the University of California, Davis and the other at Rensselaer Polytechnic Institute. Three sites provide mobile or field-installed test equipment so researchers can study the behavior of building structures and soils during actual or simulated earthquakes. Mobile field equipment at University of Texas, Austin generates earthquake-like vibrations by shaking the ground with powerful mechanical devices mounted to heavy trucks. The facility at University of California, Los Angeles has mobile shakers that apply vibrations directly to buildings, bridges, and other structures. The University of California, Santa Barbara maintains two permanent field laboratories, each consisting of a concrete test structure (building model), small shakers mounted on the structure, and sensors installed on the ground throughout the site. Large indoor testing facilities allow researchers to apply dynamic earthquake forces on large models of building structures, bridges, and other infrastructure. Steel test frames or rigid concrete walls and floors with computer-controlled actuators are used to apply large forces, similar to those exerted during earthquakes. Four such facilities are located at University of Minnesota, University of Illinois, Urbana-Champaign, Lehigh University, and University of California, Berkeley . The fifth, at Cornell University, also includes a large split-box container that can be used to test the impact of large ground movements on buried pipelines.
Astronomers may have found a way to detect alien worlds embedded in rings of dust around distant stars. Newborn stars often have clouds of leftover gas and dust around them that condense into rings called protoplanetary disks. Eventually, under the pull of gravity, the material in these disks may clump together to form orbiting planets. A team of astronomers captured detailed images of the disk around young star SAO 206462, about 460 light-years away in the constellation Lupus. For their observations, they used the HiCIAO camera on Japan‘s Subaru Telescope in Hawaii, which is designed to block out harsh central starlight that would normally make it difficult to detect fainter nearby objects, such as a disk around a star. The disk around SAO 206462 is an impressive 12.4 billion miles (20 billion kilometers) in radius, a distance aboutfivetimeslarger
Hi, my name is Lyn Neale, and I’ve always wondered if the Big Bang theory is correct, how can there be collisions of galaxies in space? Lyn, the Big Bang theory proposes that billions of years ago, the universe exploded from a tiny point. The first rapid expansion, which scientists call inflation, occurred in a fraction of a second. After inflation, the universe expanded more slowly. At this point there were no stars and no galaxies. But when the galaxies did form, they formed in clumps — or clusters — whole neighborhoods of galaxies. These galaxy clusters are still racing away from each other. But inside each cluster, the gravity of each galaxy tugs and attracts other nearby galaxies. Imagine a schoolbus full of kids. If you look at the big picture, the bus is driving away from the city center. But inside the bus, the bully in the back has no problem pushing his seatmates to the floor or grabbing someone’s ponytail. Likewise, galaxy clusters can speed away from each other while individual galaxies still collide and merge.
The Civil War Jefferson Davis in The Civil War Jefferson Davis (1808-1889) was the first and only president of the Confederate States of America. After a distinguished career in national politics as Secretary of War under Franklin Pierce, Davis served as a congressman and then as a Mississippi senator. After the South's defeat in the Civil War, he was stripped of his citizenship and took refuge in Europe, returning to the United States after a treason case against him was dropped. He died in New Orleans in 1889, and Congress posthumously reinstated his American citizenship in 1978. Davis was a moderate political leader who was never able to figure out how to defeat the better-equipped North. As president, he acted as his own Secretary of War and meddled constantly in southern military strategy. He held less power in the South than Lincoln did in the North, and the power he did have rapidly decreased as the Union Army captured large parts of the Confederacy. Davis's economic policies failed to provide the South with a stable currency or enough industrial capacity to prevail in the war. Towards the end of the war, Davis insisted on holding out until the bitter end, even when it was clear that the Confederacy had lost. In recent years, his legacy has suffered in comparison to that of Robert E. Lee, the general he appointed to replace Joe Johnston in 1862. Davis is buried in Richmond, Virginia, once the capital of the Confederacy.
The neutrino, child of desperate remedies Physicists might be tempted, at this point, to assume that placeholders are limited to the realm of a softer science like biology. The history of the neutrino, however, shows otherwise. Like genes, the neutrino was proposed decades before it was first detected. And, unlike genes, it was proposed simply to make the numbers add up. In the early studies of nuclear decay, it was possible to track all the energy and matter—a photon, an electron, and the remaining nucleus, as well as the momentum of the matter—with decent precision. Unfortunately, all that energy didn't add up. This may sound trivial now, but the discrepancy was large enough that Nils Bohr seriously considered giving up on the whole idea of the conservation of energy. A placeholder saved the day: the neutrino, a hypothetical particle that we couldn't detect but which carried away the missing energy during nuclear decays. It was nothing more than a hack to balance the books on things, and even Pauli, the man who proposed it, called it a "desperate remedy." But the physics community was apparently relieved, and a number of years later, Fermi's description of the weak force that tears atoms apart included a neutrino, largely settling matters. But the neutrino remained a placeholder, in the sense that, even though all the equations called for it, it had never been detected. It took until the 1950s for physicists to pick up hints of its existence by blocking all the radiation coming from a nuclear reactor and seeing what still hit the detector. From there on out, physicists were assured that the massless neutrinos that were slotted into the Standard Model were a physical reality. But that wasn't the last time that neutrinos and physical equations had an uneasy relationship. The physicists who modeled the Sun could, based on their understanding of fusion and the amount of energy coming from the Sun, estimate the number of neutrinos that would find their way to Earth. But, as we began to build more sophisticated detectors, we simply couldn't spot anywhere near that number. Physics was faced with a serious neutrino deficit. The folks who worked on the Sun were pretty sure they had their numbers right, which meant that, once again, there was something about the neutrino that we didn't know about, but was essential to balancing the books. An alternate possibility existed: neutrinos underwent what are called flavor oscillations, so that an electron neutrino would, with some probability, oscillate into a different type, such as a muon neutrino, and thereby escape detection. But most people considered this ludicrous because of its implications. For oscillation to occur, neutrinos must actually have mass. For all but a few specialists, this remained ludicrous right up until the day that Japan's Super Kamiokande detector confirmed that neutrinos did, in fact, undergo flavor oscillations. (It did this by comparing cosmic ray events that occurred directly over the detector to those that occurred on the opposite side of the planet, and sent neutrinos through the entire diameter of the Earth.) The role of placeholders Despite the radically different fields in which placeholders have been used, they share some basic similarities. In each case, we had a theory or principle that seemed to hold in lots of familiar cases. Traits are inherited; they show independent assortment; energy is conserved; fusion occurs the way we think it does. Putting a placeholder for something we didn't understand allowed scientists to work with very powerful theories, like evolution, genetics, and the weak force. Placeholders either enabled or preserved some very scientifically useful theories. And that's precisely what we've seen with dark matter. Relativity, which we've measured to very high precisions, appears to apply throughout the Universe. But, on scales from galaxies through to the structure of the Universe itself, everything acts like there's more mass there than we can see. So, it's not especially outrageous or unprecedented to suggest that there's mass we can't see, and slot dark matter in as a placeholder in order to retain relativity. All that's left is to actually find the particle, something we seem to be getting closer to. As we've studied more instances where dark matter shows its influence, we've actually eliminated a number of candidates, leaving us with a WIMP, a weakly interacting massive particle. Many people are expecting one of these to pop out of the LHC before too long, just as the neutrino finally was nailed down decades after we found the need for it. So far, dark matter looks like a pretty good placeholder. Right now, however, nobody even has any idea what dark energy might represent, so there's not much of a place to hold, as it were. That's likely to change as more attention is given to this mystery, though. When placeholders go bad (and why it's not so bad) Those offended by placeholders will often reference some of the more famous ones that turned out to be dead ends, like phlogiston, luminous aether, and the epicycles used to maintain circular orbits long past their sell-by dates. These were also used in place of a natural phenomenon we didn't understand well, but ended up being thrown out and replaced. Maybe a placeholder like dark matter is a big mistake, and we'll be laughing at the gullibility of today's scientists in the not-too-distant future. I'd argue that it really doesn't matter. Even when a scientific idea is wrong, as Kuhn suggested, it can still be useful if it helps organize a program of research. Epicycles were discarded not because they didn't exist, but because a different model made better predictions about the orbits of the planets. Arguments over the existence of phlogiston helped spawn the birth of analytical chemistry. The concept of luminiferous aether made enough predictions that it was possible to demonstrate that it almost certainly didn't exist well before Einstein came along. Based on the evidence and the confidence of cosmologists, I expect that we'll eventually discover the particles that produce the effects we call dark matter. But, even if we don't, I also expect that the search for these particles will have led us to some very interesting physics, and whatever replaces dark matter will be more interesting still.
the spore-producing individual or phase in the life cycle of a plant having alternation of generations Flagellated sperm; frond-like leaves; dioecious (separate sexes); evergreen are all characteristics of _______ . ______ is not needed for reproduction in seed producing vascular plants even though 2 phyla contain sperm which are flagellated; sperm will travel by eggs by pollination contained in pollen In seed producing vascular plants, _____ is packaged in seed used for dispersal of the species Referring to a plant species that has staminate and carpellate flowers on separate plants. most are evergreen with needle-like leaves; do not need water for reproduction; wind carried pollen; pollination vs. fertilization; are all characteristics of _______ . "enclosed seed" (have flowers; flowering plants produce seeds at the base of a flower resulting in a fruit; only one division) comprising seed plants that produce an embryo with a single cotyledon and parallel-veined leaves: includes grasses and lilies and palms and orchids "the eudicots" 170,000 species (oaks, hickories, violet, holly, dogwood, birches, poplars, elms, poinsettias, coleus, begonia, roses, geraniums, etc.) a seed that has one seed leaf and stored food outside the seed leaf; one cotyledon in seed A "seed leaf" which develops as a part of the seed. It provides nutrients to the developing seedling and eventually becomes the first leaf of the plant. Seed producing vascular plants have ________, therefore have xylem and phloem and roots, stems, and leaves pollen lands on stigma. pollen grain releases tube cell. tube cell divides, formiing a pollen tube all the way to the ovary. generative cell releases two sperm. sperm travel down pollen tube for fertilization. tube enters microphyle.
\|MadSci Network: Anatomy\| Alex, The walls of the air sacs (alveoli) and the pulmonary capillaries are collectively referred to as the respiratory membrane. The walls of the alveoli and capillaries (pulmonary and systemic) in the body are made of simple squamous epithelium, which is a very thin tissue. For instance, the thickness of the respiratory membrane averages only ½ of a micron (one micron is 1/1000 the thickness of a dime). The alveoli and capillary walls are the points of exchange of gasses. Most cells use oxygen to produce enough energy to carry on the basic functions of life. As cells are using oxygen to produce energy they also produce carbon dioxide. Carbon dioxide is harmful and must be eliminated from cells. Oxygen enters the blood through the respiratory membrane. Blood transports the oxygen to the systemic capillaries. There, the oxygen moves through the thin capillary walls into the cells. Carbon dioxide passes through the capillary walls from the cells. Blood transports the carbon dioxide to the lungs where it crosses the respiratory membrane and enters the alveoli. This exchange of gasses must be rapid enough so that trillions of cells can acquire the energy they need for survival. The pulmonary and systemic capillary walls and the alveoli are very thin to allow for the rapid exchange of gasses. Robert Houska Mad Scientist Try the links in the MadSci Library for more information on Anatomy.
The Drake Equation "What do we need to know about to discover life in space?" How can we estimate the number of technological civilizations that might exist among the stars? While working as a radio astronomer at the National Radio Astronomy Observatory in Green Bank, West Virginia, Dr. Frank Drake conceived an approach to bound the terms involved in estimating the number of technological civilizations that may exist in our galaxy. The Drake Equation, as it has become known, was first presented by Drake in 1961 and identifies specific factors thought to play a role in the development of such civilizations. Although there is no unique solution to this equation, it is a generally accepted tool used by the scientific community to examine these factors. -- Frank Drake, 1961 N = The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable. R* = The rate of formation of stars suitable for the development of intelligent life. fp = The fraction of those stars with planetary systems. ne = The number of planets, per solar system, with an environment suitable for life. fl = The fraction of suitable planets on which life actually appears. fi = The fraction of life bearing planets on which intelligent life emerges. fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space. L = The length of time such civilizations release detectable signals into space. Within the limits of our existing technology, any practical search for distant intelligent life must necessarily be a search for some manifestation of a distant technology. In each of its last four decadal reviews, the National Research Council has emphasized the relevance and importance of searching for evidence of the electromagnetic signature of distant civilizations. Besides illuminating the factors involved in such a search, the Drake Equation is a simple, effective tool for stimulating intellectual curiosity about the universe around us, for helping us to understand that life as we know it is the end product of a natural, cosmic evolution, and for making us realize how much we are a part of that universe. A key goal of the SETI Institute is to further high quality research that will yield additional information related to any of the factors of this fascinating equation.
Definition of of 1 —used as a function word to indicate a point of reckoning north of the lake 2a —used as a function word to indicate origin or derivation a man of noble birthb —used as a function word to indicate the cause, motive, or reason died of fluc : by plays of Shakespeared : on the part of very kind of youe : occurring in a fish of the western Atlantic 3 —used as a function word to indicate the component material, parts, or elements or the contents throne of gold cup of water 4a —used as a function word to indicate the whole that includes the part denoted by the preceding word most of the armyb —used as a function word to indicate a whole or quantity from which a part is removed or expended gave of his time 5a : relating to : about stories of her travelsb : in respect to slow of speech 6a —used as a function word to indicate belonging or a possessive relationship king of Englandb —used as a function word to indicate relationship between a result determined by a function or operation and a basic entity (such as an independent variable) a function of x the product of two numbers 7 —used as a function word to indicate something from which a person or thing is delivered eased of her pain or with respect to which someone or something is made destitute robbed of all their belongings 8a —used as a function word to indicate a particular example belonging to the class denoted by the preceding noun the city of Romeb —used as a function word to indicate apposition that fool of a husband Examples of of in a Sentence He is a coworker of mine. I threw out that old shirt of yours. She's a friend of my mother's. He had the support of his family to help him. the plays of William Shakespeare What is the name of the band? We admired the courage of the young woman. the President of the United States What is the total cost of the repairs? The value of the antique is high. Origin and Etymology of of Middle English, off, of, from Old English, adverb & preposition; akin to Old High German aba off, away, Latin ab from, away, Greek apo First Known Use: before 12th century Origin and Etymology of of First Known Use: circa 1800 Definition of OF OF Defined for English Language Learners Definition of of for English Language Learners : belonging to, relating to, or connected with (someone or something) —used to indicate that someone or something belongs to a group of people or things : living or occurring in (a specified country, city, town, etc.) OF Defined for Kids Definition of of for Students 1 —used to join an amount or a part with the whole which includes it most of the children the back of the closet 2 : belonging to, relating to, or connected with a shirt of his the top of the hill 3 : concerning I heard the news of your success. 4 : that is the city of Rome 5 : made from a house of bricks 6 : that has : with a man of courage a thing of no importance 7 —used to show what has been taken away a tree bare of leaves cured of disease 8 —used to indicate the reason for a fear of spiders Seen and Heard What made you want to look up of? Please tell us where you read or heard it (including the quote, if possible).
Individual deciduous trees mark the turning of the seasons with pale buds in the spring, densely packed green leaves in summer, vibrant red, orange, or yellow tones in fall, and bare branches in the cold of winter. Forests also mark the changes, but on a grander scale. In this series of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, forests mark the time along the southern ridges of the Appalachian Mountains, where the states of North Carolina, Tennessee, Georgia, and South Carolina all come together. The area shown in the images include different types of land cover, such as hardwood forests, pine and oak forests, and farm or grassland. Each reacts in its own way to the advancing seasons. The most striking change occurs in the hardwood forest that covers the ridges. The forest in this region is widely intact, preserved as part of Great Smoky Mountains National Park and a series of state and national forests. The forest stands out most clearly in the fall, when the maple and birch trees take on tones of orange. The loss of leaves in the winter makes it possible to see the underlying ridgelines and valleys with greater clarity. The pine and oak forests that grow in drier areas, particularly on the west side of the mountains, remain green throughout the year. They are easiest to identify in the fall and winter, when everything else is brown, yellow, or orange. The non-forested area beyond the mountains varies greatly in color. White and gray areas are cities; Dalton, Georgia, and Cleveland, Tennessee (on the left side of the image) are the most obvious. Farmland shifts from pale green in the spring, to a brighter shade of green or gold during the summer and fall, and to brown in the winter. The four images illustrate why it is critical to pay attention to the date and season of a satellite image when you try to interpret what you see. Seasons can completely alter the appearance of a landscape. Read more at How to Interpret a Satellite Image. NASA images courtesy LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek. - Terra - MODIS
Anti-Bullying and Safe Schools Resources Center for Social and Emotional Education BullyBust is an awareness campaign designed to reduce bullying in schools by teaching students and adults how to stand up to bullying and promote upstander behavior. An upstander is someone who witnesses bully behavior and does something about it Bully Police USA This watchdog organization advocates for bullied children and provides links to state anti-bullying laws, along with a rating of each law’s effectiveness. Committee for Children The Committee for Children develops evidence-based bullying, child abuse and violence prevention education curricula that teach social-emotional skills to children, families and educators. Find Youth Info A clearinghouse site for information prepared by the federal government to help prevent and address bullying in communities. Gay Straight Alliance (GSA) for Safe Schools This Wisconsin-based organization offers programs, trainings, and resources to make middle schools and high schools safe for all students, including LGBT youths. GLSEN: Gay, Lesbian and Straight Education Network Through national programs including the Day of Silence and No Name-Calling Week, GLSEN strives to assure that each member of every school community is respected regardless of sexual orientation or gender identity/expression. Center for Bullying Prevention Programs and resources for teens, parents and schools, including information on National Bullying Prevention Month (October), online surveys and a digital petition. Teens Against Bullying offers engaging activities and strategies for teens to combat bullying. National Education Association (NEA) This site provides a Diversity Tool Kit, links to anti-bullying resources (including a downloadable Safe Zone poster), and a school employee’s guide to LGBT issues. Parents and Friends of Lesbians and Gays Tools to create safe schools, a training program, updates on safe-schools legislation pending in Congress and advice for supporting LGBT parents of school-aged children. Safe Schools Coalition This public-private partnership aims to reduce bias-based bullying and violence in schools across the nation by raising awareness among students, educators and parents. Also includes content on law and public policy; Spanish-language resources; and classroom materials. “The Secret to Stopping a Bully?” This Boston Globe Sunday Magazine article examines anti-bullying programs, with a focus on bystander training. Stop Bullying Now This interactive Web site offers resources for children (including cartoons and Webisodes) and adults (including strategies for bullying awareness, prevention and intervention). Classroom activities, professional-development resources and free teaching kits to fight bias, reduce prejudice and promote tolerance and understanding of differences. Below are a few activities to reduce bullying: Bullying: Guidelines for Teachers 5 Steps To Safer Schools “THIS is Why We Need a GSA” A Bullying Quiz A Bullying Survey Early Grades Allies: A Discussion Activity Bullies Act Out Playing the Bully Card Bullying: Tips for Students A Contract on Bullying The Jamie Nabozny Case Full text of the decision from the U.S. Court of Appeals for the Seventh Circuit. Click here for the PDF version of this page.
Each student chooses an organ from either the circulatory, respiratory, digestive or excretory system. They write a web page on a wiki, describing the structure and function of that organ, including labelled diagrams. They write five “I am” statements about the organ and then find out two other organs attached to their organ and link their page to those two pages. They then create a QR code for the answer (heart, arteries, lungs etc) at either of these two sites: QR code or kaywa qr codes with the URL link that directs the reader to their wiki page. The QR code is then attached to the appropriate organ in the human torso model. For example: “I am an organ in the circulatory system that carries oxygenated blood from the heart. I have thick, muscular walls, no valves and lead to the capillaries.” The QR code scans to produce the link to the wiki page with the answer, “Arteries”, and all the information about that organ. This page would be linked to the heart and capillaries pages.
1. Choral Reading 2. Paired Reading 3. Echo Reading Today we will discuss choral reading... stay tuned for paired reading and echo reading later this week. The following quote comes from ReadWriteThink and describes the research that is found behind choral reading. "Support for choral reading is found in several reading theories and educational paradigms, including Dowhower (1987), Rosenblatt (1978), Samuels (1979), and Schreiber (1980). Through repeated readings of the text, the reader increases sight word vocabulary and ability to decode words quickly and accurately. This fluent reading enables the reader to spend less time on decoding and have greater comprehension of the text (Pikulski & Chard, 2005)." Choral reading is designed to help a child become more fluent with his/her reading. You will want to begin with a easier text selection in the beginning. This way your child will get comfortable with the process of choral reading. However, begin to select texts that are harder and harder. This will allow your child to have access to texts that he/she would not ordinarily be able to read on his/her own. He/she will then have success with a harder text. As he/she practices reading at this harder level, your child is encountering more difficult vocabulary. This gives you the opportunity to explain the meaning of the words so your child is learning the words and learning how to read the words. This builds his/her confidence, sight word knowledge, and vocabulary. When choosing material to read for this activity, consider things other than stories. You could choose poems, song lyrics, a letter, etc. Of course, books will work as well. Remember, the more interesting the material (whether it's interesting, "colorful"/descriptive, funny, or rhymes), the more fun this activity will be. How do you do choral reading? - The adult reads the selection first while the child follows along silently - The adult and the child reads through the selection together (yup... at the same time... like a CHORUS... get it? CHORAL reading) - Read through it in unison until the child feels very comfortable with that piece and his/her reading is fluent! - Select a new piece For more information, you can check out readingrockets.org
Tularemia is a disease occurring towards the end of the summer Infects people as well as animals Tularemia is a zoonosis, i.e., a disease spreading between people and animals. Several different animal species can get the infection, but its seriousness varies with the species. In people, high fever and swollen lymph nodes can be symptoms of tularemia . Among animals, mountain hares and brown hares easily catch tularemia and often die soon after having been infected. Rodents (voles, mice, lemmings, muskrats, beavers) are major hosts of tularemia bacteria. Many birds also can catch tularemia. Among pets, dogs most often do not get the disease and, surprisingly, rabbits are much more resistant than hares to the bacterium. Cats have been reported to catch the infection, which may be due to their habit of catching small rodents. Many ways to catch the disease Only a few tularemia bacteria suffice to generate the disease in people. It is spread by bloodsucking insects and infections among Finnish people most often have been transmitted by insects. Normal contacts between people directly do not transmit the disease between persons. One can get infected through wounds on hands or mucous membranes when handling animals that have died of tularemia. If the bacteria reach the eyes, they will cause conjunctivitis. Other routes of infection are through inhaled air, and intake of water or food contaminated by the bacteria. Tularemia occurs in various places in Finland. In material at Evira, an average of 8 % of hares investigated have died from tularemia. Annual variations can be significant: in 2007 nearly every fourth hare had tularemia, while in 2001 the proportion was less than 1 %. Apparently, 2009 will turn an average year as of tularemia among wild animals. This year, hares having died from tularemia have been sent to Evira from Northern Savonia, the western parts of the province of Oulu, Ostrobotnia and Kymenlaakso. Evira analyzes animal samples Evira’s Fish and Wildlife Health Research Unit in Oulu does research on diseases among wild animals. Whole carcases of animals having recently died can be sent to be analyzed for tularemia or other diseases. Avoid touching dead animals with bare hands; wash your hands immediately after handling. Instructions on the packaging and sending of animals to investigation for animal diseases, and addresses A covering letter shall always follow animals dispatched to Evira (in Finnish) Read more on tularemia on Evira’s web pages (in Finnish) and the web pages of The National Institute for Health and Welfare (THL) (in Finnish). Researcher Marja Isomursu, Fish and Wildlife Health Research Unit, marja.isomursu evira.fi, tel. 020 77 24910 or 020 77 24924
What is peripheral arterial disease? Peripheral arterial disease (PAD) is a condition where the the blood flow to the limbs, arm or leg, is impaired due to a narrowing of the arteries supplying these areas. It is more likely to affect the leg than the arm and has become a global problem due to the rise in atherosclerosis. Acute limb ischemia is the sudden occlusion of the artery as a result of clot. It needs immediate medical attention as it can lead to severe ischemia (tissue injury due to poor oxygen supply) and lead to necrosis and gangrene. This may ultimately result in a loss of the limb. Acute limb ischemia is discussed in detail under Blood Clot in the Leg. Causes of Peripheral Arterial Disease Atherosclerosis in Leg Atherosclerosis is the most common cause of peripheral arterial disease. Here the development of atheromatous plaques in the artery wall gradually narrow the lumen of the vessel and restricts the blood flow in the leg. This if often associated with hypercholesterolemia (high cholesterol levels in the blood), cigarette smoking, hypertension (high blood pressure) and diabetes mellitus (sugar diabetes). Atherosclerosis will lead to a gradual occlusion of the artery which means that the symptoms will develop slowly. Blood Clots in Leg Another common causes of an arterial blokage is a blood clot. This is a blood clot that develops at the site (thrombus) or a clot that originates elsewhere in the vascular system and lodges in a leg artery (embolus). Thrombosis in the Leg Thrombosis formation at the site is a result of turbulent blood flow and irregularities of the vessel wall thereby causing blood cells and platelets to stick to it. This forms a clot (thrombus) and can grow fairly rapidly compared to the growth of an atheroma. While the symptoms will develop more quickly than in atherosclerosis, it is still not as rapid as with an embolus. Embolism in the Leg The fastest cause of an almost complete occlusion is an embolus. This is usually a blood clot that forms elsewhere in the vascular system, dislodges from the original site and travels through the bloodstream until it occludes a leg artery which is too narrow for it to pass through. This narrowing may be as a result of an atheromatous plaque or just an anatomical difference in vessel size (luminal diameter). Emboli tend to lodge at the bifurcation of vessels and in the leg, the femoral artery is one of the common sites. Emboli may not always cause a total occlusion but with time platelet and blood cells will aggregate around the embolus and completely block off the artery (refer to the diagram above). The symptoms come on very suddenly and the consequences are serious and severe if a large or medium artery is occluded. Alternate Blood Flow As outlined in leg arteries, the blood supply to the leg is not isolated to the blood carried by the large and medium-sized arteries. Many small arteries, collateral and perforating channels ensure multiple routes for the flow of blood. This helps to limit the extent of tissue damage if the occlusion occurs in a smaller vessel. However, occlusion within a large artery or one of its medium-sized branches may result in severe ischemia (tissue injury) or even necrosis (tissue death) Symptoms of Peripheral Arterial Disease In the early stages of atherosclerotic narrowing of the artery, there may be little or no symptoms for months. One of the first and most definitive symptoms that may indicate an arterial occlusion is intermittent claudication. This is muscle pain that occurs a shortly after activity like walking and eases a few minute after rest. In most cases this is unilateral meaning that it occurs on one side unless the occlusion lies in the terminal part of the abdominal aorta. Refer to Leg Pain While Walking to differentiate between other types of claudication. As the condition progresses, leg pain may be present or even start at rest (ischemic rest pain). This will be more noticeable when lying flat because blood flow through the occlusion is aided by gravity when standing. Other symptoms include : - Pale color of leg (skin) - Shiny skin - Dryness of the skin - Hair loss on the affected leg - Unexplained itching which progresses to tingling or numbness of the leg - Muscle weakness - Leg is cool to touch - Leg pulses are diminished or absent - Arterial leg ulcer(s) as described under Ulcer on Leg Diagnosis of Peripheral Arterial Disease A differential diagnosis of peripheral arterial disease is made based on your symptoms and a physical examination where the clinical features above may be evident to your doctor. This may prompt further tests and investigations like : - Ultrasound imaging of the legs which may include a Doppler study as well to evaluate the flow of blood through the area. This is a non-invasive test and therefore the preferred investigation until P.A.D can be conclusively diagnosed. - Angiography and CTA (computerized tomographic angiography) or MRA (magentic resonance angiography) may be considered if the facilities are available. This will provide greater clarity on the location of the occlusion and degree of blood flow restriction. It may also identify other occlusions and map the overall circulation of the leg. Treatment & Prevention of P.A.D. of the Legs Conservative management is a crucial part of the treatment and management of peripheral arterial disease. Dietary changes should be targeted at a low sodium diet for hypertensive, low GI (glycemic index diet) for diabetics and low saturated and trans fat intake in hypercholesterolemia. Cessation of smoking is essential. Regular exercise involving at least 30 minutes of walking or running will assist with improving blood flow to the legs. Exercise plays a major role in symptomatic relief of intermittent claudication. The measures above are also useful for the prevention of peripheral arterial disease of the legs in high risk patients. Medication for the treatment and management of hypercholesterolemia, diabetes mellitus and hypertension is important. In addition, anticoagulants may also be necessary like aspirin and clopidrogel. This may also offer symptomatic relief for intermittent claudication. Cilostazol helps with arterial dilatation and preventing blood clots. - Balloon angioplasty may help to widen the occluded artery and compress the atheromatous plaque thereby restoring blood flow to the limb. - Bypass surgery is not regularly conducted on the leg unless the occlusion is severe and the patient is not responding to medication and cnservative management or if an angioplasty is of limited benefit Article reviewed by Dr. Greg. Last updated on November 22, 2010
In a new report, the U.S. Geological Survey (USGS) assessed the ecological risks that nine giant non-native snake species would bring if they were ever established in the United States. The result: Five of them pose a high risk and four pose a medium risk. The nine species, including non-native boa, anaconda and python species, are invasive or potentially invasive in the United States. However, the authors write in their report that "at present, the only probable pathway by which these species would become established in the United States is the pet trade." Among the high risk species are Burmese pythons, northern and southern African pythons, boa constrictors and yellow anacondas. These species put larger portions of the U.S. mainland at risk, constitute a greater ecological threat, or are more common in trade and commerce. Medium-risk species, including the reticulated python, Deschauensee’s anaconda, green anaconda and Beni anaconda, constitute lesser threats in these areas, but still are potentially serious threats. Both Burmese pythons and boa constrictors have been documented as reproducing in the wild in South Florida, with population estimates for Burmese pythons in the tens of thousands, although there has been some debate about whether or not the pythons will migrate out of this habitat. The high risk snakes "mature early, produce large numbers of offspring, travel long distances, and have broad diets that allow them to eat most native birds and mammals,” which increases their risk to ecosystems, the authors wrote. In addition most of these snakes can inhabit a variety of habitats and are quite tolerant of urban or suburban areas, they said. Boa constrictors and northern African pythons, for example, already live wild in the Miami metropolitan area. The authors also note that native U.S. birds, mammals, and reptiles in areas of potential invasion have never had to deal with huge predatory snakes before — individuals of the largest three species reach lengths of more than 20 feet and upwards of 200 pounds. USGS researchers used available science data to forecast areas of the country most at risk of invasion by these giant snakes. Based on climate alone, many of the species would be limited to the warmest areas of the United States, including parts of Florida, extreme south Texas, Hawaii, and America’s tropical islands, such as Puerto Rico, Guam, and other Pacific islands. For a few species, however, larger areas of the continental United States appear to exhibit suitable climatic conditions. For example, much of the southern U.S. climatic conditions are similar to those experienced by the Burmese python in its native range. However, many factors other than climate alone can influence whether a species can establish a population in a particular location, the report says. Individuals of some species may also pose a small risk to people, although most snakes would not be large enough to consider a person as suitable prey. Mature individuals of the largest species — Burmese, reticulated, and northern and southern African pythons —have been documented as attacking and killing people in the wild in their native range, though such unprovoked attacks appear to be quite rare. The snake most associated with unprovoked human fatalities in the wild is the reticulated python. The situation with human risk is similar to that experienced with alligators: attacks in the wild are improbable but possible. The report also notes that there are no control tools yet that seem adequate for eradicating an established population of giant snakes once they have spread over a large area. Making the task of eradication more difficult is that in the wild these snakes are extremely hard to find since their camouflaged coloration enables them to blend in well with their surroundings. “This report clearly reveals that these giant snakes threaten to destabilize some of our most precious ecosystems and parks, primarily through predation on vulnerable native species,” Dr. Robert Reed, a coauthor of the report and a USGS invasive species scientist, said in a statement. The Fish and Wildlife Service and the National Park Service will use the 300-page report to assist in further development of management actions concerning the snakes when and where these species appear in the wild. In addition, the risk assessment will provide current, science-based information for management authorities to evaluate prospective regulations that might prevent further colonization of the U.S. by these snakes. - Image Gallery: Snakes of the World - Will Deadly Pythons Spread Beyond Florida? - All About Snakes
Table of Contents What is generalized anxiety disorder (GAD)? Anxiety is a word that describes feelings of apprehension, concern, fear, nervousness, restlessness, or worry. Normal feelings of anxiety often serve as an “alarm system” that alerts you to danger. Your heart may beat fast. Your palms may get sweaty. Anxiety can provide an extra spark to help you get out of danger. It can also give you the energy to get things done in more normal but busy situations. Anxiety can be a general feeling of worry, a sudden attack of panicky feelings, or a fear of a certain situation or object. Sometimes, anxiety can be out of control. You may feel a sense of dread and fear for no apparent reason. This kind of anxiety can disrupt your life. Generalized anxiety disorder is ongoing anxiety that isn’t related to a particular event or situation. It can also be anxiety that is not “normal” about a situation. For instance, a person who has GAD may constantly worry about something that is unlikely to happen. They let these worries interfere with ability to function. Women are more likely to have GAD than men. It usually begins to affect people when they are in their teens and early 20s. Symptoms of generalized anxiety disorder Most people worry from time to time. These occasional worries are normal. They don’t mean that you have GAD. If you have GAD, you worry so much that it interferes with your day-to-day life. You feel tense and worried more days than not. Other signs of GAD include: - trouble falling or staying asleep - muscle tension - trouble concentrating - getting tired easily - restlessness, or feeling “keyed up” or on edge - shortness of breath - fast heartbeat - dry mouth If you feel tense most of the time and have some or all of these symptoms, talk to your doctor. They will ask questions to make sure that something else isn’t causing your symptoms. He or she will also perform a physical exam. What causes generalized anxiety disorder? Suppose the fire alarm goes off in your home. You race around frantically to find the fire. Instead, you find that there is no fire. The alarm just isn’t working properly. It’s the same with anxiety disorders. Your body mistakenly triggers your alarm system when there is no danger. This may be due to a chemical imbalance in your body. It may also be related to: - An unconscious memory. - A side effect of a medicine. - An illness. Sometimes, certain kinds of medicine may cause GAD. You could also have symptoms if your thyroid gland is too active. Depression can also cause them. GAD sometimes runs in families. How is generalized anxiety disorder diagnosed? Your doctor will ask you about your symptoms and health history. He or she will perform a physical exam to make sure a physical or medical condition is not causing your symptoms. If your doctor doesn’t find any other reason for your symptoms, you may need to be treated for GAD. Can generalized anxiety disorder be prevented or avoided? There is not a specific cause for GAD. This means it can’t be prevented or avoided. The best thing to do is to address the symptoms as soon as possible. Then you can get started on a treatment plan and live a normal day-to-day life. Generalized anxiety disorder treatment People who have GAD must learn ways to cope with anxiety and worry. Your doctor can help you form a plan to develop skills to cope with your anxiety. The plan may include counseling, medicine, or both. Counseling can help you figure out what’s making you so tense. Your doctor may prescribe medicine to help you feel less anxious. They can recommend the treatment that is right for you. Living with generalized anxiety disorder People who have GAD can get better. If you take medicine for it, you may be able to stop taking it at some point in the future. Your doctor will tell you if it’s OK to stop taking your medicine. The most important things are to talk about it, seek help, and take action. Action can help you gain a sense of control. The following are some tips on coping with anxiety: - Control your worry. Choose a place and time to do your worrying. Make it the same place and time every day. Spend 30 minutes thinking about your concerns and what you can do about them. Don’t dwell on what “might” happen. Focus more on what’s really happening. Then let go of the worry and go on with your day. - Learn ways to relax. These may include activities such as yoga or a walk around the block. - Breathe deeply. Follow these steps to take a break during your day to just breathe: Lie down on a flat surface. Place one hand on your stomach, just above your navel. Place the other hand on your chest. Breathe in slowly and try to make your stomach rise a little. Hold your breath for a second. Breathe out slowly and let your stomach go back down. - Relax your muscles. Start by choosing a muscle and holding it tight for a few seconds. Then relax the muscle. Do this with all of your muscles, one part of your body at a time. Try starting with your feet muscles and working your way up your body. - Exercise regularly. People who have anxiety often quit exercising. But exercise can give you a sense of well being and help decrease feelings of anxiety. - Get plenty of sleep. Sleep rests your brain as well as your body. It can improve your general sense of well being and your mood. - Avoid alcohol abuse and drug abuse. It may seem that alcohol or drugs relax you. But in the long run, they make anxiety worse and cause more problems. - Cut down on caffeine. Caffeine is found in chocolate, coffee, soft drinks, and tea. Caffeine may increase your sense of anxiety because it stimulates your nervous system. Also avoid over-the-counter diet pills and cough and cold medicines that contain a decongestant. - Confront the things that have made you anxious in the past. Begin by just picturing yourself confronting these things. Then you can get used to the idea of confronting the things that make you anxious before you actually do it. - Use medicine, if it helps. Your doctor may give you medicine to help reduce your anxiety while you learn new ways to respond to the things that make you anxious. Many types of medicine are available. Your doctor will decide which medicine is right for you. Questions to ask your doctor - What treatment is best for me? - How do I know what is causing my anxiety? - Are there any lifestyle changes I should make? - Should I change anything in my diet? - What kind of exercise will help me? - How can I stop worrying about everything? - Do I also have depression? - Will I have to take this medicine for the rest of my life? Copyright © American Academy of Family Physicians This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.
Muscular dystrophy is a group of genetic diseases where the skeletal muscles weaken and break down over time. These muscles are important for movement, so this is often impaired in patients. It also has a direct correlation to a disease of the heart known as cardiomypathy. The most common forms of the disorder are Duchenne muscular dystrophy and Becker muscular dystrophy. The mutation which causes this disease occurs on the gene DMD, which codes for the protein dystrophin. The disease was discovered when a neurologist from France named Guilaumme Duchenne (likely where the name of the disease came from) wrote about the disease in the 1860’s. The incidence rate of the disease in the United States is about 1 in every 6,667 boys and men between the ages of 5 and 24. Worldwide, 1 in between 3,500 and 5,000 newborn male babies have muscular dystrophy. Out of these people, those of Hispanic or white race were generally more affected, while those of African American lineage weren't as affected by the disease. Symptoms include: Skills such as walking or standing do not come easily, wheelchair-bound by teenage years, heart muscle grows and irregular heartbeat, immense fatigue, legs/feet swell, often short of breath, endocrine system might function improperly, causes learning disabilities and brain function Muscular dystrophy is treated through a variety of methods, such as physical and occupational therapies, splints and braces, aids to make movement and walking possible, corticosteroid medications, and antispasmodic treatments to help muscle spasms. Muscular dystrophy is far more likely to occur in males then females, because the mutation occurs on the sex chromosome X. Since men only have one of the chromosome, the gene only needs to mutate on one chromosome. But in females, the mutation needs to occur on both X chromosomes. This disease is inherited and is a recessive trait, making it quite rare. The prognosis for someone with muscular dystrophy is anywhere between 20-40 years. With treatment, however, a patient's life expectancy could move into later adulthood. Diagnosing a patient with muscular dystrophy is a multi-step process, where many forms of testing have to be done. Some of these tests are muscle biopsies and genetic testing for the mutation of the gene. Blood tests are done for an enzyme called serum creatine kinase, which is release when muscles break down. Imaging with MRIs and ultrasounds to look at the quality of the muscle is also done. Recently, the National Human Genome Research Institute founded the Center for Mendelian Genomics, which includes muscular dystrophy (a Mendelian disease). Their job is to investigate the genes that codes for particular proteins as a cause of disease. As of 2016, they are planning on providing $40 million in funding for the center. Other up and coming research includes work done by the Muscular Dystrophy Association. Current trials are being undergone for different forms of cures, including exon skipping and gene therapy. As of Sept. 2016, eteplirsen became the first drug approved by the FDA to help muscular dystrophy (disease-modifying drug).
\|University of Kentucky Department of Entomology\| Mystery Bug Answers Mystery Picture #13 Scorpions pack a punch in their tails. The front pinchers are used to grab and hold their prey- usually small insects. While we typically think of them in hot deserts or tropical jungles, there is a species that occurs in much of Kentucky and over the southeast. To read more about our Kentucky scorpion, Centruroides vittatus,jump to Scorpions in Kentucky. The Wheelbug is a beneficial insect with piercing sucking mouthparts. Its sharp beak, extending from the front of its head, is usually carried in a groove along its body between the legs, so it does not show up well in this picture. The front legs are fitted for grabbing prey (usually caterpillars)- much like a praying mantis does. The common name of this insect comes from the back hump which resembles half of a gear wheel. This page is maintained by Pat Dillon, Department of Entomology, University of Kentucky. Please send questions or suggestions to: [email protected]
Content Analysis Process I sought an easy way for students to conduct rudimentary content analysis using Microsoft Word and Excel. - Open Microsoft Word and a web browser. - Identify primary documents you wish to analyze. Find the online text using a search engine (I like Google), or the links below. - Use your mouse to highlight the text portion of your document. (Note: documents in .pdf must be saved as text.) - Copy the selection. - Paste the selection into Microsoft Word. From now one you will work with Word. - Go to the Word Toolbar, select "Tools," then Word Count. - Copy the data. You may want to enter the data into a spreadsheet like Microsoft Excel. - Now begin to query the data by looking for words or phrases. On the Toolbar, go to "Edit" and then "Find." A box entitled "Find and Replace" will appear. Click on the "Replace" tab. Select the "More" option on the left side of the bottom row. Make sure that you have selected Search "All." Type the word you have chosen into the line labeled "Find what." [Note: Under the default option, Word will replace any string of characters even if it appears within a word. For example "government" would replace "government," "Government," "governments," and "Governments" or any other extension of the word unless you choose "options" and select "match case" and/or "find whole words only." You may want to use the default option if you are looking for themes such as "free" instead of just "freedom."] - Click on the "Replace all" button and make sure that you have searched the entire document (not just to the end of the document). - Word will tell you how many replacements have been made. - Record the word you have "replaced" and the number of replacements. After collecting your data, you will probably want to chart the information. See examples of student-generated charts using the assignment below: Students were asked to identify three "policy" speeches to get a better sense of U.S. government concerns over time. They chose George Washington's Farewell Address, the Monroe Doctrine, and Dwight Eisenhower's speech on the military-industrial complex. They applied the content analysis methods outlined above. After analyzing these data, the students chose to add Nikita Khrushchev's Secret Speech as a different, comparative dimension. Students then charted the frequency of the selected words both as a word count and as a percentage of the speech.
It's important to remember that kids can't read until they understand the fundamentals of how we read. This includes understanding what a cover is, the author and illustrator roles, reading from left to right, and top to bottom. Once these skills are mastered, they'll be able to read words in the correct order to form sentences, sentences to form paragraphs, and so forth. This fun series of worksheets guides your little one through concepts like how to turn a page, which direction to read, and the difference between letters and words. And the best part? You can print out these worksheets and make them into your own personalized book!
Listen as glass artist William Gudenrath describes the technique of making a core-formed vessel. The technique of core forming, which was introduced around the middle of the 16th century BC, was used to fashion some of the first glass vessels. Core forming involves the application of glass to a removable core supported by a rod. There is no consensus about how this was accomplished. Some scholars believe the glassmaker wound trails (strands) of molten glass around the core, or dipped the core into molten glass. Others suggest that a paste of powdered glass was applied to the core and fused with heat. After forming, the object was removed from the rod and annealed (slowly cooled to room temperature). Once the object had been annealed, the core was removed by scraping.
Mamberamo River, also called Tarikaikea, river in northwestern New Guinea, in the Indonesian province of Papua. Formed by the confluence of the Taritatu (Idenburg) and Tariku (Rouffaer) rivers, which converge in a large wild sago swamp, it flows generally northwest and empties into the Pacific Ocean near Cape Narwaku (D’Urville). After flowing placidly for the first 20 miles (32 km), the river cuts through the Van Rees Mountains in a series of rapids and gorges. Including its headstream, the Taritatu, the Mamberamo is about 500 miles (800 km) long and forms the largest drainage system of Indonesian New Guinea. It is navigable for 100 miles (160 km) from its mouth, but the only settlements consist of small villages. Click anywhere inside the article to add text or insert superscripts, subscripts, and special characters. You can also highlight a section and use the tools in this bar to modify existing content: Add links to related Britannica articles! You can double-click any word or highlight a word or phrase in the text below and then select an article from the search box. Or, simply highlight a word or phrase in the article, then enter the article name or term you'd like to link to in the search box below, and select from the list of results. Note: we do not allow links to external resources in editor. Please click the Websites link for this article to add citations for
Daily VideoJune 16, 2017 At the 50th anniversary of Loving v. Virginia, an author looks back on race in America - In 1967, the Supreme Court struck down laws banning interracial marriage. The case was Loving v. Virginia. Richard and Mildred Loving were briefly thrown in jail for marrying each other in Virginia in the 1950s. - Laws banning interracial marriages in Virginia date back to colonial chattel slavery, when the capitalist class wrote into the slave codes laws against interracial sex and marriage. - Georgetown University law Professor Sheryll Cashin wrote a book called “Loving: Interracial Intimacy in America and the Threat to White Supremacy,” discussing the history of how relationships between people of different races have challenged racist ideology. - Cashin said that since the founding of America, two opposing ideas have been at play: Jeffersonian ideologies of egalitarianism and universal human dignity, and a regime of white supremacy. Despite his professed egalitarian ideas, Jefferson himself was a slave owner. - Cashin believes that cultural dexterity in the United States is growing. Cultural dexterity is the ability to understand and appreciate differences rather than expecting others to assimilate to your culture. - Essential question: How much progress has the United States made in race relations? - What other court cases, besides Loving v. Virginia, were instrumental in the civil rights movement? What did they do? - What actions can you take to be more culturally dexterous? Tooltip of related stories Tooltip of more video block Submit Your Student Voice Use this PBS NewsHour video and discussion questions to teach your students about the events in Charlottesville. Extension activities include the history of Confederate monuments and the debate as to whether or not the statues should remain standing. Continue readingArts & CultureEconomicsHealthScienceSocial StudiesU.S.UncategorizedWorld Today’s Daily News Story provides video, key terms and discussion questions to help teachers talk with their students about the events in Charlottesville, Virginia. Continue readingArts & CultureEconomicsHealthScienceSocial StudiesU.S.UncategorizedWorld Montpelier, the home of James Madison, the fourth president of the United States, recently opened a new permanent exhibit at the Virginia estate to inform visitors about Madison’s slaves and the lives they led. Continue readingArts & CultureEconomicsHealthScienceSocial StudiesU.S.UncategorizedWorld As high-density, industrial-scale livestock feeding operations become the norm, farmers have had to take extra steps to keep animals healthy. Illnesses and diseases grow and spread quickly when large numbers of similar animals are kept in close proximity. Continue readingArts & CultureEconomicsHealthScienceSocial StudiesU.S.UncategorizedWorld Rose-ringed parakeets have multiplied by the thousands on the Hawaiian island of Kauai since the 1960s, when a few parakeets kept as pets escaped. The birds have since caused problems by damaging native plants and farm crops. Continue readingArts & CultureEconomicsHealthScienceSocial StudiesU.S.UncategorizedWorld
Speech and Language Problems in ASD A Neurologist's Persective/A Parent's Perspective Problems with speech and language are one of the defining characteristics of the Autism Spectrum Disorders. However, the difficulties that individuals with autism have with speech and language are very heterogenous and probably have a number of different causes or contributing factors, even in the same individual. My colleagues and I have been trying for some time both to investigate the speech and language problems that can occur in autism and to develop possible treatments for them. In addition, I am the father of a nonverbal 14 year old with autism. What follows is a general overview of my perspective on these problems and how they can be assessed and approached for what treatment is possible. Any actual assessment and treatment plan of any particular individual needs to be far more detailed and follow much more detailed logic than this overview allows. However, I am hopeful that it will still be useful for helping parents and teachers interpret what is wrong, what is right, and what can be done to possibly make things better for such individuals. Normal Speech and Language The fullest expression of normal human speech and language requires the desire or intent to communicate something. Also, in its fullest form, it also requires an appreciation of what the other individual understands about a situation and how they are supposed to react to what is being communicated. As the next stage beyond the formulation of an intent or goal in communication, speech and language normally require a mental representation of the message (semantics), next, a representation of the message in terms of words (mentally), and, finally, an articulation of the mental words as physical sounds (articulation of speech). Other ways of expressing mental words are possible, such as gesture (including sign language) or typing. Messages may also have an emotional component that, in English, is signalled by changes in the volume or pitch. Comprehension of speech and language is normally done through sound. This requires paying attention to the sounds, then being able to decipher the sounds in terms of words, then being able to understand the words in terms of intended meanings, and, finally, appreciating the meanings in terms of intentions, actions, or what have you. Vision (perception of gestures and signs or of printed words) and touch (Braille) can also be used as alternative or additional routes into the perception of letters and words. Impairments in Individuals with Autism Individuals with autism can have problems with any or all of these aspects involved in producing or understanding speech and language. In particular, for example, because of their deficits in appreciating social situations, they may not feel any need to communicate and may very well not have any understanding of how other people might respond to a communicated message. Individuals with autism frequently appear to have deficits in paying attention to auditory information. They frequently have to be trained to pay attention to sounds. Even when they are paying attention, many individuals with autism seem to have difficulty in decoding what sounds mean and in matching them to words or thoughts. In some individuals with autism, this may be because they actually have difficulties with words and thoughts themselves. In others, it may be more because of a mapping problem. Individuals with autism frequently have difficulties with articulation, often as part of a broader problem of difficulty with oral-motor functions (movements of the lips and tongue and associated breath control). On the plus side, however, individuals with autism are frequently very good with paying attention and appreciating visual materials. Therefore, the visual route is often one way of getting access to their minds and giving them a way of expressing themselves, in turn. In any given individual, which particular problems they have and which problems are hampering them most in any particular stage of development can only be determined by a careful assessment. Standardized testing can help to some extent, but it requires careful administration and interpretation, in part, because many standardized tests were not developed with a consideration of the kinds of deficits that individuals with autism may have. Therefore, both the administration and the interpretation of such tests may be problematic because of the unusual pattern of performance. To give just one example, because of their markedly restricted interests, individuals with autism may only rarely show any particular verbal ability and may never show the ability when placed in an unusual testing situation with an unfamiliar examiner. In such a case, the reports of parents and teachers who are more familiar with the child’s capabilities can provide an important clue to what is possible for them and what is not. In our research and educational program, we try to construct for each child an individualized map of their abilities and disabilities. Is the child aware that he or she is being spoken to? Do they ever try to communicate by any means? Are they echolalic (that is, do they repeat sounds or words spoken to them)? Echolalia, for example, is a clue that the child can perceive speech and articulate speech, so any problems that they may be having with speech and language must be beyond those levels. Individuals with autism may have problems impeding their development of speech and language that are well outside the scope of traditional speech and language therapy (such as social deficits) or, at the very least, in the very frontiers of clinical knowledge as to appropriate treatment (developmental articulation disorders). Parents and teachers are confronted by a bewildering range of options and apparent philosophies of treatment of these individuals. However, what really matters most is the empathy, energy, and flexibility of the particular therapist or therapists. In many cases, for example, therapists with seemingly very different philosophies will have surprisingly similar treatment plans because of the realities of the particular individual they deal with.
Listening and Hearing, though synonyms, are completely different. Hearing is a step-by-step process. Hearing is simply the act of perceiving sound by the ear. Even if youare not hearing, still it happens. Listening is something that one consciously chooses to do. It requires concentration, so that one is able to process meanings from words and sentences. Listening leads to learning. You can listen to someone without actually hearing them. Hearing occurs even in sleep, where the ear processes the sounds and passes them to the brain. Listening is also known as ‘ Active Listening’. It is a technique that is used in commuication, which requires a person to pay attention to the speaker and provides feedback. Listening is a step ahead of Hearing. Listening requires one to derieve meaning from the sound that is heard and then react to it. Listening is the process of communication, where if the person is not listening, it can cause a break in communication. There are 4 types of communicators: 1. Passive Listeners: Passive Listeners are those who hear the words but refrain to absorb the meaning and provide vague answers at the end of the communication. 2. Non- listeners: Non-listeners are those who are pre-occupied in their own thoughts and ideas, though they are listening, they may not give attention. 3. Listeners- Listeners are those who hear and listen but grasp only things that are of their interest. This is common for those who only listen and cease feeding anything in the conversation, as they are aware that their views are different. 4. Active Listeners- Active listeners are the best in the category. They not only listen and hear, but also listen with an open mind and have patience. They are completely focused on the speaker. Thus, the major difference between hearing and listening is, while hearing one just refers to the ears picking up sounds but listening means to interpret those sounds, understand them and provide an adequate response.
Learn something new every day More Info... by email Computational neuroscience is a diverse and interdisciplinary science. It combines many fields, such as cognitive science, electrical engineering, physics, and computer science into one cohesive field. Its aim is to explain a range of biological, brain, and neural system-related phenomena from a multidisciplinary standpoint. The information gained from such studies could be useful in the future of various medical fields. The overall, supreme goal of computational neuroscience is to explain the phenomenon of consciousness. The field has several main areas of focus. One focus is the ability of the human brain to discriminate and to learn. Humans and animals have the ability not only to distinguish between various things, such as walls and trees, but also to tell the difference between very similar things, such as faces. People will still recognize the face of an old friend in a crowd, even after several years of separation. Normal as this may sound, it is an astounding feat that neuroscientists are still struggling to understand. The behavior of neural networks is another important focus of computational neuroscience. This focus primarily utilizes the field of computer science. Scientists are seeking to understand the methods and patterns of signal transfer throughout the brain. This is essential to neural modeling, making precise models of neural interactions in the brain. Memory, a topic that has bewildered psychologists for decades, is integral to computational neuroscience. Neuroscientists are working to explain the changes that memories experience over time. Essentially, they want to fully explain short-term, medium-term, and long-term memory. The current study of memory largely focuses on synapses, how they change over time, and how they respond to external stimuli. Individual neurons are a major subject of interest in computational neuroscience. Networks of neurons send signals throughout the body. Motor neurons tell parts of the body to act, while sensory neurons report to the brain about external stimuli, such as temperature. While neurons are only single cells, they are extraordinarily complex. Scientists are beginning to see that they respond differently to different stimuli and can, indeed, adapt over time if necessary. Computational neuroscientists hope to explain these phenomena in one cohesive neural model. The nervous system, from the brain to the tips of the toes, has escaped full explanation for ages. Consciousness, the thing that truly sets humans apart from the other organisms, is still beyond the scope of biology or psychology. Computational neuroscience combines several fields to explain these human mysteries. Eventually, the field may reach a conclusion about consciousness itself. One of our editors will review your suggestion and make changes if warranted. Note that depending on the number of suggestions we receive, this can take anywhere from a few hours to a few days. Thank you for helping to improve wiseGEEK!
Energy Harvesting Systems Power the Powerless Abstract: Energy harvesting (also known as power harvesting or energy scavenging) allows electronics to operate where there is no conventional power source, thus eliminating the need for wires or replacement batteries. This article describes several unconventional energy sources that can be used to power circuitry, and outlines applications for the process. It also explains design challenges that must be addressed to implement a fully functional energy harvesting solution. A similar version of this article appeared in the January 2012 issue of Bodo's Power Systems. Modern electronic systems solve so many difficult problems that they often seem like magic. Nonetheless, these systems all have the same basic limitation: they need a source of electrical power! Most of the time this is a straightforward challenge for the electronic designer, because there are many power-delivery solutions. Yet sometimes a device has no direct power source, and running wires or replacing batteries is impractical. Even when long-life batteries are usable, they eventually need to be replaced, which requires a service call. Enter energy harvesting. Energy harvesting (also known as power harvesting or energy scavenging) allows electronics to operate where there is no conventional power source. It eliminates the need for wires or replacement batteries. This article discusses energy harvesting and its applications. It explains how the process works and the challenges that designers must address to implement a fully functional solution. What Is Energy Harvesting? Energy harvesting uses unconventional energy sources to power circuitry. Typically, a tiny energy source is converted to electricity and stored in a durable storage cell such as a capacitor, super capacitor, or microenergy cell (MEC), which is a form of lithium solid-state battery. The system generally includes circuitry to manage the power and protect the storage device and other circuitry. Sources of energy (Figure 1) include light, captured by photovoltaic cells; vibration or pressure, captured by a piezoelectric element; temperature differentials, captured by a thermoelectric generator; radio energy (RF); and even biochemically produced energy, such as cells that extract energy from blood sugar. Figure 1. Energy harvesting uses unconventional sources to power circuitry. Energy Harvesting for Remote and Portable Applications While energy harvesting can be considered "free energy," energy cost is not what motivates most solutions. Modern energy harvesting is used because it eliminates the need to run expensive power cables to remote locations or the need to replace expensive primary batteries frequently. In simple terms, energy harvesting systems are more convenient and reduce costs for many applications. There is, however, more to their appeal. Energy harvesting systems are also ResourceSmart® designs. They eliminate wasteful batteries and long powerline runs. They keep systems running without inconvenient, disruptive service calls. They enable monitoring and control at remote locations and especially in sensitive ecological settings. Applications for energy harvesting focus on management of remote sites, systems, and mobile devices. Typical uses are control of remote sensors, remote wireless sensing devices, asset tracking and personnel identification systems for building access, and enhanced security at remote locations. Specific examples include energy supplied for remote valves for pipelines, irrigation, and other systems that include plumbing but no power; safety and control equipment that monitors oil and gas pipelines; electrically operated automatic flush toilets; wearable electronics attached to clothing or protective gear; surgically implanted electronics such as drug-delivery, monitors, and pacemakers; and smart cards, which contain circuitry but no power source. Energy harvesting is also proving useful with a variety of real-time clock (RTC)/memory backup applications and asset tracking or identification. The Technical Challenges of Energy Harvesting Energy harvesting solutions demand much from the electronics that support them. Consider some of these design challenges. If the energy resource is not always present, then the system needs to store energy in a battery, super capacitor, or microenergy cell. Moreover, since energy sources vary, the system must convert, regulate, and control that energy. The circuitry and the energy storage cell must all be protected from excess voltage or power spikes. The supporting electronics must be highly power efficient since the energy source is generally small. Remote systems powered by energy harvesting must be very reliable. A service call negates any advantage of the remote control. Finally, remote systems often lack climate control or are subject to fluctuating environmental/temperature conditions. Any energy harvesting system must accommodate and operate flawlessly under those conditions. Energy Harvesting for the Future The Maxim MAX17710 energy-harvesting charger and protector is a new-generation power-management IC that "harvests" the energy generated from a variety of poorly regulated energy-harvesting sources (Figure 1). The MAX17710 provides the energy harvesting and power management to maximize, protect, and control the energy stored in microenergy cells such as Infinite Power Solutions THINERGY® microenergy cells (MECs) (Figure 2 ). The ultra-thin, postage-stamp-sized MECs are flexible and provide unmatched rechargeability, cycle life, and power performance. They have extremely low self-discharge rates and enable decades of shelf life. In fact, these two devices make energy harvesting practical. Figure 2. The MAX17710 shown in a typical application circuit harvesting from high-voltage charge sources. The MAX17710 integrates an input boost regulator so it can boost charges from as low as 800mV. It needs no expensive external components to charge an MEC and harvests energy from 1µW to 100mW. To protect the MEC, the MAX17710 handles input source voltages higher than the MEC and regulates or shunts excess power. An ultra-low-quiescent-current, low-dropout linear regulator (LDO) with selectable voltages of 3.3V, 2.3V, or 1.8V prevents potentially damaging overdischarge of the MEC. This also allows the MAX17710 to adapt to a variety of loads, because undervoltage protection recovers only when an external energy source raises the voltage of the MEC back into a safe zone. Temperature extremes are another concern. At very low temperatures, all batteries exhibit increased characteristic impedance which limits high pulse currents to the application loads. The MAX17710 integrates a unique feature that manages an external storage capacitor in order to provide high pulse currents. Energy harvesting solutions allow electronics to operate where there is no conventional power source and without the need to run wires or make frequent visits to replace batteries. Using unconventional power sources, the energy-harvesting circuit manages the power generated and protects the energy storage device. Since the energy source is not always present, the energy harvesting system also needs to store the energy. Energy-harvesting applications are poised to expand rapidly. Some applications are in development that will demonstrate how practical, efficient, cost-efficient, and "clean" energy harvesting is. It is clear that each new implementation with a microenergy cell is going to need some energy-harvesting charger and protection circuit like the MAX17710. ResourceSmart is a trademark and registered service mark of Maxim Integrated Products, Inc. THINERGY is a registered trademark of Infinite Power Solutions, Inc. The content on this webpage is protected by copyright laws of the United States and of foreign countries. For requests to copy this content, contact us. \|© Mar 29, 2012, Maxim Integrated Products, Inc. APP 5259: Mar 29, 2012 APPLICATION NOTE 5259,
Unpredictable glow of galactic dust could undermine biggest cosmological discovery in years J.-P. Bernard/Planck Collaboration; R. Flauger On March 17, Lloyd Knox, a cosmologist at the University of California, Davis, joined scientists around the world in celebrating a Nobel Prize–worthy discovery. That day researchers from the Background Imaging of Cosmic Extragalactic Polarization project announced that their telescope at the South Pole, BICEP2, had detected a subtle twirling pattern imprinted on light that had traveled across the universe for 13.8 billion years. The measurement was impeccable, the implications profound. The imprint, the BICEP researchers said, could be made only by gravitational waves, ripples in space triggered when the universe explosively kick-started its expansion a split second after the Big Bang. If the results held up, they would serve as the first direct evidence of that rapid expansion, known as inflation, which was predicted in 1981 to explain the uniform structure of the cosmos (
What Are Biomes? By: Jacky Gabriel A biome is a community that is characterized with different plants and species of animals. It is maintained under the conditions of that region. There are so many different types of biomes I will name some that I know of and give you some information on them. - A desert biome is a dry area of land that contains no vegetation and is water less. - There are four types of deserts,they are: Hot and Dry deserts, Semi Arid deserts, Coastal deserts, and Cold deserts. - There is at least one desert in every continent except for Europe. - There is a very low population of living things. - The only plants that are capable of living in the desert are yuccas, sotol, and cacti. - These plants are able to survive because they are able to conserve water. - A grassland is an open area that is full of grass and used for grazing. - There are two types of grassland biomes: Savanna and Temperate grasslands. - The Savanna grassland is different from the Temperate grassland because the soil in the Savanna is layered and aren't capable of holding water. - Animals that you might see in a Savanna grassland are: lions, hyenas, snakes, giraffes, buffalos, and lots of insects - The Temperate grassland contain extreme weather conditions with very hot summers and very cold winters. - Animals you might find in the Temperate grassland are: owls, hawks, deer, mice, rabbits, spiders, and foxes. - Temperate grasslands with short grasses are called "steppes" and Temperate grasslands with tall grasses are called "prairies". - In both types of grasslands there is moderate rainfall, not too little to cause a drought or too much to cause a flood. - A tundra is a flat, treeless Arctic region where the subsoil is permanently frozen - There is the Arctic Tundra and the Alpine Tundra - The word Tundra comes from the word Tunturi which by definition tells us that its a treeless plain or a barren land. - A tundra is a fragile, soft, biome that shrinks as the permafrost melts. - Polar bears come out in the summer where they have they're babies. - Animals living in the tundra have short ears and tails so they won't lose heat. - Plants that grow in the tundra grow in groups, they are sometimes known as cushion plants Forest Biomes: Tropical Rainforests, Temperate Forest, and Taiga Forest - A tropical rain forest is an area with tall evergreen-leaved trees with a high annual rainfall - The soil has little nutrients inside of it - Animals like squirrels,frogs, and snakes can be seen roaming around this type of forest - Rainforest affect that weather of the world - For every second, a size of a football field of trees is cut down from the rainforest - About 2% of the sun's sunlight hits the forest floor, meaning most o fit just hits the tree tops - Temperate forests are formed in the northern and southern hemispheres. - Animals that live in these forests have claws to climb the trees - Temperate forests in Eastern Europe are dying because of acid rain - The taiga forests are characterized with coniferous trees and run across North America and Eurasia. - In the past the taiga had been covered with glaciers - Wild fires help the taiga because it burns a new area where new plants can grow - Taigas' are endangered forests due to logging Tropical Rainforest Biome A tropical rainforest picture Temperate Forest Biome A description of a Temperate forest Taiga Forest Biome Taiga Forest idea Aquatic Biomes: Marine, Freshwater - Examples of marine biomes are oceans and coral reefs. Animals found in this biome could be star fish, sharks, and tuna. The Great Barrier reef is a marine biome. - Examples of freshwater biomes are lakes,ponds,rivers, and streams. Animals found in this biome are crabs, salmon, and tilapia worms. An example of a freshwater biome is the Amazon River.
Homo floresiensis essay Homo floresiensis is a small-bodied hominin species that is dated to between 95,000 and 17,000 years ago. Known from a single cave on the island of Flores in eastern Indonesia, H. floresiensis displays a surprising combination of cranial features that resemble those of Homo erectus and Homo sapiens, postcranial features (features of the limb and trunk) that most closely resemble those of species in the genus Australopithecus, and a stone tool technology linked to those often associated with H. sapiens. If the fossils assigned this species do not represent a population of pathological H. sapiens, as some researchers have argued, they represent a new hominin species and suggest H. sapiens shared the planet with another species much more recently than previously believed. The cranial material of H. floresiensis comprise teeth and mandibles (lower jaws) from multiple individuals and a single, nearly complete skull. The skull and teeth share some derived features (features not found in the common ancestor) shared with H. erectus and H. sapiens. The face is small, specifically in facial height (a measurement between the brow and the upper teeth) and exhibits reduced prognathism (how far the upper and lower jaws project out from the face) compared to australopith species. The H. floresiensis molars (the teeth at the back of the jaw) and canines are also relatively small, similar to the condition found in H. erectus and H. sapiens.. These Indonesian fossils also possesses many primitive features similar to earlier hominins. For example, the brain is very small (380 to 420 cubic centimeters) and is more similar to apes and species in the genus Australopithecus. The mandibles and premolars (bicuspid teeth), which represent at least 8 partial individuals, share distinctive primitive traits with both Australopithecus and Homo habilis. The premolars are asymmetrical and elongated with complex tooth roots. The mandibles are relatively robust and large in size; yet lack a chin (central part of the lower jaw that protrudes out from the face, found only in H. sapiens mandibles). In contrast to the cranium, where only one complete skull was found, postcranial remains from multiple individuals have been recovered. The shoulder joint is cranially oriented (toward the skull) and the clavicle (collar bone) is short and very curved, suggesting the shoulder was high on the torso, as seen in apes and species in the genus Australopithecus. Other aspects of the postcranial skeleton of these Flores finds that are shared with Australopiths include relatively long arms, flared pelves (plural of “pelvis”; pelvic blades that extend beyond the hip joint) and relatively short legs. Moreover, the hand and wrist of H. floresiensis seem to be more primitive than even the earliest representatives of the genus Homo (H. habilis) and closely resemble the shape found in Australopiths. The primitive morphology (size and shape) of the H. floresiensis hand and wrist suggests this species lacked the ability to precisely manipulate items with their hands. Interestingly, the foot of this species is similar to H. sapiens in some respects: the big toe is aligned with the other toes and the bones are thick and robust. Nevertheless, the overall foot morphology exhibits a generally primitive pattern. For instance, the foot is approximately 20 centimeters in length, much longer than any H. sapiens foot from an individual of comparable height to the short statured Homo floresiensis individuals, resembling more closely the length of chimpanzee and australopith foot. The toes exhibit primitive features such as long and curved lateral toes (the four toes to the outside of the feet; all but the hallux or big toe) and the hallux is quite short in comparison to that possessed by H. sapiens . The H. floresiemsis foot also seems to lack the longitudinal arch that is characteristic of H. erectus and H. sapiens. Some researchers argue the Flores remains are those of a diseased individual of our own species and have suggested a number of pathologies that could explain the mosaic of features exhibited by these remains. Pathologies that have been suggested include various forms of microcephaly (a class of genetic disorders in which the head and brain are abnormally small) and growth disorders, such as hypothyroidism (a condition in which the thyroid gland does not produce enough hormones that regulate the body’s metabolism) and Laron’s Syndrome (a genetic disorder in which the body does not process growth hormones normally). Detailed comparisons of the H. floresiensis material, however, seem to provide little support for these hypotheses because measurements of the remains fall outside of modern H. sapiens ranges of variation, even when compared to those with the aforementioned pathological conditions. Moreover, no pathological syndrome seems to adequately explain the suite of features exhibited by H. floresiensis. The fact that all of the individuals found at the cave site exhibit similar cranial and postcranial morphology casts further doubt on the hypothesis that the H. floresiensis remains are those of pathological H. sapiens, as it is unlikely multiple individuals would show signs of relatively rare diseases. Considerable attention has also been paid to the evolutionary history of Homo floresiensis—e.g., how did it get to Indonesia and of which previously known hominin species is it a descendant? Some researchers have suggested H. floresiensis represents a dwarfed descendent of Asian H. erectus populations. However, there is no evidence for larger-bodied (non-dwarfed) ancestors of H. floresiensis on the island, making this hypothesis difficult to test. This fact and H. floresiensis’ primitive anatomy (brain size, limbs, pelvis, hands and wrist) has led some anthropologists to postulate the remains are evidence of a pre-Homo erectus migration of an earlier species in the genus Homo or a species in the genus Australopithecis. Another hypothesis is that H. floresiensis descended from an earlier, more primitive type of H. erectus (such as that represented by H. erectus remains from the site of Dmanisi in the Republic of Georgia; see essay on H. erectus). Most researchers agree the current anatomical evidence shows that H. floresiensis is in many ways more similar to early Homo species (e.g., Homo habilis) than to later Homo species. This observation supports the idea that the ancestors of H. floresiensis left the African continent before the evolution of H. erectus, but the precise origins of this species remain unknown. The stone artifact assemblages found in association with the skeletal remains of H. floresiensis are dense and demonstrate continuity in production method and tool type throughout the cave deposits. There are a large number of bifacial (struck on both sides) and radial (struck from the outer edge towards the center) cores (rocks from which pieces [flakes] are chipped to produce tools), similar to the Oldowan stone artifact assemblages in East Africa. More complex tools—e.g., points (sharpened, pointed tools), perforators (tools designed to make holes or incisions), blades (flake that is at least twice as long as it is wide) and microblades (blades less than 10 mm, often components of composite tool technology)— have also been recovered. The combination of primitive, Oldowan-like core technology with more advanced tool assemblages is quite uncommon in the archaeological record and make interpretations of the stone tool assemblages found in association with H. floresiensis difficult. Some researchers have questioned whether H. floresiensis had the cognitive capacity to make the more complex tools, citing its small brain size. However, no skeletal remains of H. sapiens have been found at sites bearing Homo floresiensis skeletal material and artifacts commonly associated with the symbolic behaviors of Homo sapiens (e.g., personal ornaments, pigments, and formal disposal of the dead) are also absent, suggesting that H. floresiensis was the manufacturer of all of the tools found at this site. Researchers have recently recovered stone tools from a site close to the cave on Flores Island. This site dates to roughly 1.02 million years ago and therefore provides a new minimum age for hominin inhabitation of the island. The artifacts found at this site are similar to those found at the original site; they are small flakes and both bifacially and radially struck cores. However, the absence of skeletal remains at this second site disallows the establishment of a direct link between H. floresiensis (or any other hominin species) and this stone tool assemblage. The reconstructed paleoenvironment for H. floresiensis spans three cycles of glacial (cold, dry periods) to interglacial (warm episodes between glacial intervals) changeovers. The earlier cave sediments suggest a wet, rich surrounding environment with dense forests. However, a shift is indicated after 39,000 years ago and Flores begins a transition to more arid conditions. There is a reduction in rainfall and forest cover, as well as the development of widespread grasslands. The environment changed yet again 17,000 years ago and became gradually more wet. The appearance of parrots in the assemblage suggests that the local flora was changing into a more closed canopy forest, similar to present day environments.
Probability Lesson Plan Probability Lesson Plan Students learn what probability is by predicting the outcome of planned experiments, and playing racing games. Standards (NCTM 3-5) Data Analysis and Probability Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them. Understand and apply basic concepts of probability. - collect data using observations, surveys, and experiments. - Describe events as likely or unlikely and discuss the degree of likelihood using such words as certain, equally likely, and impossible. - Predict the probability of outcomes of simple experiments and test the - Understand that the measure of the likelihood of an event can be represented by a number from 0 to 1. Students must be able to: - perform basic mouse manipulations such as point, click and drag - use a browser such as Netscape for experimenting with Teacher will need an opaque bag containing marbles of two different colors. Students will need: - access to a browser - pencil and paper - miniature car - race game board - Focus and Review - Chose a student to come to the front of the class. - Ask the class who they think will win if you and the student race across the classroom. - Let the student have a 1/2 of the room head start. Now ask the class who they think will win. - Prompt the students to use terms like: likely, unlikely, and impossible. - Inform the students that what they are discussing has to do with the mathematical term "probability" - Students will understand mathematical terms such as more likely and less likely and apply those terms to real life situations. - Perform simple experiments to collect data. - Determine the probability of different experimental - Understand computers can be used to help make time consuming calculations much less cumbersome. - Teacher Input - Hold up your opaque bag and allow your students to see that there is nothing inside the bag. - Place 4 white marbles in the bag. Allow the students to watch you place the marbles in the bag. - Hold up the bag and ask the students what color marble you will pull out of the bag if you were to reach in and grab a marble. - Prompt the students to make the connection that you will definitely pull out a white marble, because they are the only marbles in - Place the marble back in the bag and add 4 marbles of a different color. - Ask the students which color marble is most likely to be pulled out of the bag and why. - If the students don't realize right away that the chances of pulling out either color marble is equally likely begin pulling out one marble at time, recording what color it is, and replacing it back in the bag. You may want to allow the students to pull the marbles out of the bag to help involve them and keep their attention. - Empty the bag. Place 3 white marbles and 1 marble of a different color in the bag. - Begin with this set of questions: - Which color marble am I more likely to pull out of the bag? Why? - Will I always pull out a white marble? - How much of a chance do I have of pulling out the other color - Explain that you have a 1 in 4 chance of pulling out a non-white marble. - Do the experiment manually to show the students the results. The more you repeat the experiment the closer your results will be to the - Explain that 1 out of 4 chances can be represented as a fraction or a percent and show them how this is done. - Guided Practice - Allow the students to partner up. - Explain to the students that they are going to perform a probability experiment. using miniature cars, a race board, and die. - Tell them the rules you wish them to follow. - Have the students calculate the theoretical probability of each car winning on a one step board if: - Player A moves when he/she rolls a 1, 2, or 3 and player B moves when he/she rolls a 4, 5, or 6. - Player A moves when he/she rolls a 1 or 2 and player B moves when he/she rolls a 3, 4, 5, or 6. - Pass out the game boards and cars. - Have the students run the races manually a few times. - Compile the class' results and compare them to the results that the - Ask the class what they think caused the discrepancies in the their experimental results and their theoretical results. - Ask the class if they believe performing the experiment more times would make their experimental results closer to the theoretical - Ask them how long they think it would take them to perform that experiment 10,000 times. - Explain that this type of experiment is one of this things that computers are really helpful for, because they can perform them extremely rapidly. - Have the students open the Racing Game with One Die applet and show them how to operate it. - Instruct the students to turn off their monitors. - Have the students predict the probability of a car A winning a two step race if car A moves on rolls of 1, 2, 3, and 4 and car B moves on rolls of 5 and 6. - Instruct the students to turn their monitors back on and run the race 10,000 times. - Ask the students if the answers they came up differed from the computer generated - Ask the students if they have any theories as to why their answers differed from the computer generated answers. - Show them the math behind the correct answer and point out how much quicker it was to use the computer to check their math rather than having to manually run the races using the cars and dice. - Independent Practice - Have the students calculate the theoretical probabilities for each of the questions. - Have the students use the computer to help them complete the Modifications and Extensions - Review new terms: probability, theoretical probability, experimental probability, likely, unlikely, impossible, and definitely. - Connect the vocabulary with the experiment. - Talk about how computer applications can be useful when working with This lesson can easily be modified to help meet the needs of more advanced - Having them calculate the probabilities for games with more steps. - Having them do the calculations for 2 dice and using the Racing game with Two Dice.
In this era of technological advancements, possessing digital skills has become a necessity for individuals across all walks of life. Digital skills encompass a range of abilities that enable people to navigate, comprehend, and utilize digital technologies effectively. From basic computer literacy to advanced programming and data analysis, these skills play a pivotal role in enhancing personal and professional growth in the 21st century. This article delves into the concept of digital skills, and their various facets, and highlights their significance in shaping the modern world. Table of Content Digital skills refer to a broad set of competencies required to operate, understand, and leverage digital technologies and tools. These skills encompass both technical and cognitive abilities that empower individuals to thrive in the digital age. Source: SafaltaFrom using smartphones and social media to performing complex data analyses or programming tasks, digital skills cover a wide spectrum of proficiencies. - Basic Digital Skills: Basic digital skills encompass fundamental abilities such as operating a computer, using word processing software, sending emails, and browsing the internet. These skills are the foundation for digital literacy and are essential for individuals to function in today's society. - Communication Skills: Digital communication skills involve using various online platforms and tools to connect and collaborate with others. Proficiency in email etiquette, social media usage, video conferencing, and instant messaging are all vital aspects of effective digital communication. - Information Literacy: Information literacy pertains to the ability to evaluate, access, and utilize information found online critically. With the vast amount of data available on the internet, possessing the skills to distinguish credible sources from unreliable ones is crucial for making informed decisions. - Digital Security and Privacy: Understanding digital security measures and safeguarding personal information online is a significant component of digital skills. Individuals must be aware of potential cyber threats and be equipped to protect their data and digital identity. - Digital Content Creation: Creating digital content involves the ability to produce and share media, such as videos, images, and written content. This skill is valuable for personal expression, branding, and marketing purposes. - Data Analysis and Interpretation: With the proliferation of data in the digital world, the ability to analyze and draw insights from data sets has become increasingly important. Skills in data analysis and interpretation empower individuals to make data-driven decisions and solve complex problems. - Programming and Coding: Coding skills have emerged as a valuable asset in the digital landscape. The ability to write and understand code enables individuals to develop websites, mobile applications, software, and automated solutions. In an era where technology plays a central role in nearly every aspect of life, digital skills have become a prerequisite for success and meaningful participation in society. The following are some of the key reasons why digital skills hold immense importance: - Employability and Career Advancement: In the modern job market, employers seek individuals with a diverse skill sets, including digital competencies. From administrative roles that require basic computer literacy to highly specialized positions in software development or data science, digital skills are in high demand. - Digital Citizenship: As the world becomes increasingly interconnected through the internet and social media, digital citizenship becomes crucial. Understanding the responsible use of digital technologies, adhering to online etiquette, and being aware of cyberbullying and digital safety issues are all aspects of being a responsible digital citizen. - Lifelong Learning: The digital landscape is constantly evolving, with new technologies and tools emerging regularly. Individuals with strong digital skills are better equipped to adapt to these changes and engage in continuous learning throughout their lives. - Access to Information and Opportunities: The internet provides a vast repository of information and opportunities. With digital skills, individuals can access educational resources, job opportunities, and online services, even from remote locations, thus bridging the digital divide. - Innovation and Entrepreneurship: Digital skills are the driving force behind innovation and entrepreneurship. In today's digital economy, startups and businesses rely heavily on technology and digital platforms. Possessing digital skills enables individuals to turn innovative ideas into tangible products or services. - E-Government and Digital Services: Governments worldwide are increasingly adopting digital platforms to deliver services and engage with citizens. Digital skills empower individuals to access government services, participate in e-democracy, and make informed decisions as responsible citizens. - Enhancing Personal Productivity: Digital tools and applications have streamlined various aspects of life, from managing schedules and finances to organizing tasks and communication. Digital skills help individuals leverage these tools to enhance personal productivity and efficiency. In conclusion, digital skills have become indispensable in today's fast-paced, technology-driven world. From basic digital literacy to advanced programming and data analysis, these skills empower individuals to thrive personally and professionally. The ability to communicate, create, and interpret information in the digital realm opens up a world of opportunities and ensures a competitive edge in the job market. Moreover, digital skills foster responsible digital citizenship and promote lifelong learning in a constantly evolving digital landscape. Embracing and enhancing digital skills is not only beneficial for individuals but also contributes to the progress and development of society as a whole. As we continue to navigate the digital era, fostering digital literacy and equipping individuals with the necessary digital competencies remains imperative for building a brighter, more inclusive future. Related article: Top 10 Ways to Achieve Search Engine Optimization (SEO) Strategies
Mark the integers on the number line. Locate real numbers on a number line. The real numbers between 2 and 6 18. 7th grade the real number system worksheet answer key. Comparing and ordering real numbers answer key displaying top 8 worksheets found for this concept. In seventh grade students will study pre algebra topics such as integer arithmetic simplifying expressions the distributive property and solving equations inequalities. Real number 8th grade displaying top 8 worksheets found for this concept. The real numbers greater than 4 10. This worksheet is a supplementary seventh grade resource to help teachers parents and children at home and in school. Whole numbers w integers z rational numbers q real numbers r. The real numbers less than 5 15. The real numbers less than 0 12. The real numbers less than 2 17. The real numbers less than 3 14. The real numbers greater than 2 13. 7th grade math worksheets to engage children on different topics like algebra pre algebra quadratic equations simultaneous equations exponents consumer math logs order of operations factorization coordinate graphs and more. Each worksheet is in pdf and hence can printed out for use in school or at home. The real numbers less than 4 16. It has an answer key attached on the second page. Some of the worksheets displayed are sets of numbers in the real number system algebra 1 name homework 8 the real number system date unit 1 real number system homework real numbers and number operations science 7th grade number system crossword 2 name teksstaar based lessons the real. Number system worksheet for 7th grade children. Covers the following skills. Some of the worksheets displayed are elementary math work grade 8 mathematics practice test elementary math work eighth grade answer key 8th grade math common core warm up program preview science 8th grade number system crossword name functions 1 mathematics florida standards mafs grade 8. The real numbers greater than 1 11. B answer the questions using the number line below. Showing top 8 worksheets in the category eighth grade math with answer key. Some of the worksheets for this concept are sets of numbers in the real number system sets of real numbers date period grade 8 mathematics practice test organizing numbers mathematics 8th grade math standard 1 8th to 9th grade summer math packet operations with grade level 8th compare and order rational numbers. 7th grade math worksheets pdf printable math activities for seventh grade children. Or if there were i would use it to take pictures. Some of the worksheets for this concept are comparing and ordering rational numbers name comparing and ordering real numbers work write comparing and ordering numbers ccomparing and ordering real numbersomparing and ordering work compare and order rational numbers hands on compare and. All worksheets come with an answer key placed on the 2nd page of the file. 8th grade math worksheets and answer key study guides. Identify the square root of a perfect square to 400 or if it is not a perfect square root locate it as an irrational number between two consecutive positive integers. They continue studying ratio and percent and learn about proportions. This is a math pdf printable activity sheet with several exercises.
In the ever-evolving landscape of education, the focus on holistic development has gained significant traction. Recognizing that a child's growth encompasses more than just academic prowess, educators and researchers are placing a greater emphasis on Social and Emotional Learning (SEL) within the framework of the "Whole Child Approach." This approach addresses the multifaceted nature of a child's development, promoting skills that extend beyond traditional academics and fostering well-rounded individuals equipped to navigate the challenges of an interconnected world. Understanding Social and Emotional Learning Social and Emotional Learning (SEL) refers to the process through which individuals acquire and apply skills necessary for understanding and managing emotions, developing empathy, establishing and maintaining positive relationships, and making responsible decisions. SEL is not just about improving interpersonal skills; it's about cultivating emotional intelligence, self-awareness, and resilience. These skills are invaluable assets in personal, academic, and professional spheres. The Whole Child Approach: Beyond Academics The Whole Child Approach acknowledges that children are more than just students; they are complex individuals with social, emotional, physical, and cognitive dimensions. While academic achievement remains crucial, the approach recognizes that focusing solely on grades and standardized test scores neglects other vital aspects of a child's development. By integrating SEL into the curriculum, schools can address the diverse needs of students and provide a comprehensive education that prepares them for a balanced and fulfilling life. Key Components of the Whole Child Approach Cognitive Development: Academic excellence remains integral, but the Whole Child Approach underscores the importance of tailored learning experiences that cater to diverse learning styles. When combined with SEL, cognitive development becomes more effective, as emotional regulation and interpersonal skills enhance a student's capacity to grasp complex concepts. Social Development: Healthy relationships are the cornerstone of a fulfilling life. SEL equips students with the skills to communicate effectively, resolve conflicts, and collaborate. These skills not only foster positive interactions within school but also prepare students for the intricacies of social dynamics beyond the classroom. Emotional Development: Understanding and managing emotions are crucial life skills. SEL cultivates emotional intelligence, enabling students to navigate stress, anxiety, and other challenges. Emotionally intelligent individuals are better equipped to cope with setbacks and adapt to changing circumstances. Ethical Development: The ability to make responsible and ethical decisions is paramount in today's complex world. SEL encourages students to develop a strong moral compass, guiding them toward ethical choices and actions. Benefits of the Whole Child Approach Improved Academic Performance: SEL enhances focus, self-discipline, and resilience, leading to improved academic outcomes. Emotionally healthy students are better equipped to handle academic challenges and setbacks. Enhanced Social Skills: Students with strong social skills are more likely to form positive relationships, leading to a more inclusive and supportive school environment. Reduced Behavioral Issues: SEL equips students with conflict resolution skills and emotional regulation techniques, which can contribute to a reduction in disciplinary problems. Long-Term Well-Being: The skills acquired through SEL support lifelong mental health and emotional well-being, enabling individuals to effectively manage stress and build fulfilling lives. Preparation for the Future: The evolving job market requires skills beyond academics. The Whole Child Approach prepares students for success in a world that values collaboration, adaptability, and emotional intelligence. The Whole Child Approach, with its integration of Social and Emotional Learning, represents a paradigm shift in education. Recognizing that a child's development is multifaceted, this approach ensures that students are equipped with the skills needed not just for academic success, but also for emotional resilience, interpersonal competence, and ethical decision-making. By nurturing the "whole child," educators lay the foundation for individuals who are not only prepared for the challenges of the future but are also empowered to lead fulfilling and impactful lives.
Tapeworms can cause intestinal infections. When they do, any of a number of tapeworm species may be involved. These may include Taenia saginata (beef tapeworms), Taenia solium (from pork), or Diphyllobothrium latum (from fish). Tapeworms require human hosts to live out their life cycles. They affect people through contact with contaminated human feces found in soil, fresh water, or food. Children can develop these diseases by eating raw or undercooked meat from animals or fish that are infected with tapeworms. Contaminated food contains cysts of the parasite. Your child may have a tapeworm infection and have no symptoms. When a child eats tapeworm cysts in undercooked beef, pork, or fish, the cyst survives the stomach acids and releases the larvae. The parasite grows within the child’s bowel to become an adult tapeworm. The adult tapeworm has up to 1,000 segments called proglottids, each of which contain 30,000 to 100,000 eggs. A proglottid separates from the adult and travels out of the intestines with the stool. The segment is about 0.5 to 1 inch in length and can sometimes be seen moving in the stool or on the anus. If a child or adult has an adult tapeworm, they will pass segments filled with eggs in their stools. These eggs are then released onto soil and eaten by cattle or pigs, in which they hatch, enter the bloodstream, and form cysts in the meat, completing the parasitic life cycle. These eggs can also get onto the hands of humans and then into foods that they are preparing. The eggs of the fish tapeworm do not affect humans. These eggs need a different host called a copepod, which is a small fresh-water shrimplike animal. The copepod is eaten by a fish, which then becomes contaminated with the tapeworm, thus completing the life cycle. The eggs of the beef tapeworm also do not affect people. However, when a person eats an egg from pork tapeworms, the egg hatches in the bowel and the larva emerges. The larva then burrows through the wall of the bowel to enter the bloodstream. Because the larva is not in a pig (the preferred host of a pork tapeworm), it cannot go through its normal life cycle. Thus, in its human host, the larva gets stuck in tissues such as the muscles, liver, and brain. Within the tissue, the larva forms a cyst. Cysts within the brain can cause seizures. When adult tapeworms cause human illness, doctors use the name taeniasis to describe the infection. In contrast, when pork tapeworm larvae lead to illness, it is called cysticercosis. Tapeworm infections tend to be more common in parts of the world with poor sanitation systems or where beef, pork, and fish are eaten raw or poorly cooked. Some tapeworms can grow up to 30 feet and live as long as 25 years! Signs and Symptoms Many tapeworm infections are symptom free. When symptoms are present, they often include - Stomach pain Fish tapeworm competes with its human host for vitamin B12 in the intestine and, in prolonged cases, can cause pernicious anemia. Children who ingest pork tapeworm eggs can develop tapeworm cysts (cysticercosis) within their internal organs. If these cysts occur in the brain, they can cause serious symptoms such as seizures, behavioral disturbances, and even death. When to Call Your Pediatrician Contact your pediatrician if you notice something moving in your child’s stool that could be a worm segment, your youngster has prolonged stomach pain, or any of the other symptoms appear without another, more obvious cause. If you think your child might have been exposed to tapeworms within the past 2 to 3 months, let your pediatrician know. Make sure your doctor is aware if your child has traveled recently to a developing country. How Is the Diagnosis Made? To diagnose a tapeworm infection, your pediatrician will send your child’s stool sample for tests to detect eggs or worm segments of the suspected tapeworm. Children with cysticercosis usually do not have adult tapeworms. Therefore, eggs are not usually found in the stool. Blood tests can be done to look for antibodies to the tapeworm. In patients with seizures, imaging of the brain with computed tomography (CT) or magnetic resonance imaging (MRI) is performed to look for cysts or other abnormalities. Your pediatrician may prescribe oral drugs such as praziquantel or, as an alternative, niclosamide to treat a tapeworm infestation. These medicines are typically given in a single dose. Other antiparasitic drugs, including albendazole and praziquantel, are available specifically for treating cysticercosis. Anticonvulsant medications should be used to control seizures if they occur. What Is the Prognosis? Drug treatment for tapeworms is very effective and can completely kill the parasite. Treatment for the cysts will get rid of them, but the area of the brain may remain abnormal and seizures may continue. To reduce your child’s risk of developing tapeworm infections, do not allow him to eat raw or undercooked fish, beef, or pork. Be sure he always practices good hygiene, including regular hand washing, especially after using the bathroom. To avoid cysticercosis, be sure that all food handlers wash their hands. Proper sanitation is the key to the elimination of tapeworm infestation worldwide.
English Language Arts and Literacy Videos From the Page to the Classroom: Implementing the Common Core State Standards- English Language Arts and Literacy The CGCS-developed video “From the Page to the Classroom: Implementing the Common Core State Standards (CCSS) in English Language Arts and Literacy” provides the background of the CCSS and the three shifts that are inherent in these standards. David Coleman and others who helped develop the standards. The video includes New York City classroom footage taped by Lily Wong-Fillmore showing how ELL kindergarten students are engaged in reading and discussing ideas from complex text in English. The video has start and stop points to allow for discussion to build a shared understanding of the shifts. Classroom Example of Teaching Complex Text: Butterfly This video features a New York City kindergarten class of English language learners demonstrating Lily Wong-Fillmore's guidance in how teachers can support students in acquiring and using academic language and working successfully with complex text. \| Click here to play video
The quantity of litter in the world’s oceans has been steadily rising as a result of river pollution and poor waste management in many areas of the world. Although it is the most isolated body of water on the planet, winds and ocean currents mean that the Southern Ocean is not exempt from this pollution, and debris is common on its waters and shores. On the shores of the subantarctic islands, tonnes of waste (mainly plastics) are washed up every year. Remnants of fishing gear such as bait straps, ropes, nets, floats and buoys, and domestic rubbish such as bottles, bags, shoes, bottle tops and the like are, unfortunately, plentiful. Many of these are often mistaken for food by wildlife. Recent research shows that the amount of debris on subantarctic islands is directly proportionate to the level of commercial fishing in the area. Strapping, nets and ropes entangle seals and penguins, and often lead to a slow and painful death. Small floating plastic fragments, such as polystyrene beads and chips, can be mistaken for food by surface feeding birds. Its frequent ingestion results in death. Oil and chemicals spilled into the Southern Ocean’s cold waters may take many years to break down, and can cause irreversible harm to the seals, penguins, and other wildlife living on its shores. All of Australia’s continental Antarctic stations have waste water and sewage treatment equipment which minimises the effects of waste dispersal into the sea. The volume of effluent released, its Biological Oxygen Demand (an estimate of the numbers of micro organisms) and suspended solids (to estimate the amount of organic matter) are constantly monitored. Sludge from the plant is removed to Australia, and the AAD is currently trialling UV sterilisation of the remaining effluent. As a signatory to the Madrid Protocol and the International Convention for the Prevention of Pollution from Ships (MARPOL),which accords Antarctic waters the highest level of protection, Australia and other Antarctic Treaty parties require their Antarctic shipping to meet stringent standards. All ships chartered by the AAD have strengthened hulls to provide added protection against potential oil and fuel spills, and operate on light diesel fuels. Annex IV of the Madrid Protocol and MARPOL provide protection to the marine environment from the effects of ship operations, including: - bilge water, oil, and oily mixtures - waste storage, treatment and discharge - sewage storage and treatment - exhaust emissions. The AAD is researching the amount and nature of debris on Macquarie and Heard Islands to determine its harmful effects and how best to limit them. As a requirement of Antarctic Treaty Resolution I/1997, Australia has developed an oil spill contingency plan for each of its permanent Antarctic and subantarctic stations, and also requires its chartered ships to have a current contingency plan. Plans conform to the guidelines established by the Council of Managers of National Antarctic Programs (COMNAP). All expeditioners undergo basic training in fuel management, with specialist training provided for those handling major fuel transfers. Antarctic Treaty Parties are working with the International Maritime Organisation to develop a comprehensive set of guidelines for Antarctic shipping, which are intended to protect human safety, the environment and shipping.
Native, common and widespread The smallest of the UK’s voles, bank voles have a reddish-chestnut coat with a dirty white underside. The bank vole tail is under half the length of their body and they have a blunt nose with small eyes and ears. At first sight, they can be confused with field voles, which are greyer, or wood mice, which have a longer tail and bound rather than scurry. Bank voles are active during both the day and night, and forage over distances up to 50 metres. Males sometimes travel further to find a mate. They make their nests in shallow burrows that they dig just beneath the ground, which they line with leaves, grasses, moss or feathers. They are very nimble climbers and often climb up bushes to nibble fruit and buds. Head-body length: 8 – 12cm Tail length: Less than half the body length Weight: 14 – 40g Lifespan: Up to 18 months Litters of 3 – 5 blind, hairless young are born between April and October and become independent within nine weeks but over half of those born early in the season will die before they are four months old. Grass, roots, fruit such as apples, seeds, and also insects and earthworms. Broadleaf woodland, scrubland, hedgerows and sometimes gardens where there is plenty of ground cover and food. Tawny owls, weasels and foxes. Habitat loss and agricultural pesticide use. Status & conservation Native to Great Britain; populations in Ireland were accidentally introduced in the 1950s. Common and widespread. Bank voles are not legally protected in the UK and have no conservation designation. UK population size & distribution UK population 23,000,000. The population trend is unknown. Bank voles are widely distributed throughout Britain and the south west of Ireland. Did you know? A close relative (subspecies) of the bank vole is present on Skomer Island off the south west coast of Wales. The Skomer vole arrived there hundreds of years ago and is twice the size of its mainland relative.
Early life on Earth limited by enzyme 22 August 2019 A single enzyme found in early single-cell life forms could explain why oxygen levels in the atmosphere remained low for two billion years during the Proterozoic eon, preventing life colonising land, suggests a UCL-led study. The enzyme–nitrogenase–can be traced back to the universal common ancestor of all cells more than four billion years ago. Found only in bacteria today, nitrogenase is nevertheless essential for the production of oxygen from water in photosynthesis, making it instrumental in how aquatic bacteria produced Earth’s first molecular oxygen 2.5 billion years ago. “For half of Earth’s 4.6 billion year existence, the atmosphere contained only carbon dioxide and nitrogen, with no oxygen, but this changed when cyanobacteria, also known as blue-green algae, started producing the first oxygen using nitrogenase. This led to the Great Oxidation Event,” explained study author Professor John Allen (UCL Genetics, Evolution & Environment). “But instead of rising steadily, atmospheric oxygen levels stabilised at 2% by volume for about two billion years before increasing to today’s level of 21%. The reasons for this have been long debated by scientists and we think we’ve finally found a simple yet robust answer.” A study, published today in Trends in Plant Science by researchers from UCL, Queen Mary University of London and Heinrich-Heine-Universität Düsseldorf, proposes for the first time that atmospheric oxygen produced using nitrogenase blocked the enzyme from working. This negative feedback loop prevented further oxygen from being made and initiated a long period of stagnation in Earth’s history about 2.4 billion years ago. Lasting nearly two billion years, the Proterozoic Eon saw very little change in the evolution of life, ocean and atmosphere composition and climate, leading some to call it the ‘boring billion’. “There are many ideas about why atmospheric oxygen levels stabilised at 2% for such an incredibly long period of time, including oxygen reacting with metal ions, but remarkably, the key role of nitrogenase has been completely overlooked,” said study co-author Professor William Martin (Heinrich-Heine-Universität Düsseldorf). “Our theory is the only one that accounts for the global impact on the production of oxygen over such a sustained period of time and explains why it was able to rise to the levels we see today, fuelling the evolution of life on Earth.” The team says that the negative feedback loop ended only when plants conquered land about 600 million years ago. When land plants emerged, their oxygen producing cells in leaves were physically separated from nitrogenase containing cells in soil. This separation allowed oxygen to accumulate without inhibiting nitrogenase. This theory is supported by evidence in the fossil record that shows cyanobacteria had begun to protect nitrogenase in dedicated cells called heterocysts about 408 million years ago, once oxygen levels were already increasing from photosynthesis in land plants. “Nitrogenase is essential for life and the process of photosynthesis as it fixes nitrogen in the air into ammonia, which is used to make proteins and nucleic acids,” said co-author Mrs Brenda Thake (Queen Mary University of London). “We know from studying cyanobacteria in laboratory conditions that nitrogenase ceases to work at higher than 10% current atmospheric levels, which is 2% by volume, as the enzyme is rapidly destroyed by oxygen. Despite this being known by biologists, it hasn’t been suggested as a driver behind one of Earth’s great mysteries, until now.” The work was funded by the Leverhulme Trust, European Research Council, Volkswagen Foundation and the German Research Foundation (DFG). - Research published in Trends in Plance Science - Professor John Allen's academic profile - UCL Centre for Biodiversity & Environment Research - UCL Genetics, Evolution & Environment - UCL Biosciences - UCL Life Sciences - Anabaena cylindrica, a filamentous cyanobacterium, 1946 watercolour by G. E. Fogg, FRS Tel: +44 (0)20 3108 3846
In Kazakhstan, English was set as an important language for Kazakh students to gain profound knowledge at a good university or college; hence, the language class is crucial for them to pass the unique national test in English. Yet, this examination test focuses on grammar and reading ability. There is no part for checking the communicative ability of the student. That is why most of the teachers at school are exploiting the Grammar Teaching method to teach English, which focuses on the grammatical structure. Thereby, this present teaching situation directs students to pay attention to grammar not to speaking. Students of our country are taught English from the second grade at gymnasium and lyceum and from the ﬁ fth grade at public general schools; hence, students learn English for seven or ten years. But, seven or ten years study cannot show good results, because they are unable to speak freely or engage in real life situations without hesitation. Students have good grammar but weak speaking. Why do we need perfect grammar if we cannot use it in speech? Communication is the most important aspect of our daily life that needs language. The result is that the method of teaching must be changed partly by integrating new ways of There are different methods to teach English, such as the Structural Approach, Grammar Teaching, Communicative Language Teaching etc.. And Communicative Language Teaching is the most suitable approach to teach and improve the speaking ability of students, because it is learner-centered and emphasizes communication ability and real – life situations. So, the function of the teacher is just a facilitator to direct the student to reach his/her target. In our traditional way of teaching a teacher has the main role and it is teacher – centered which cannot give any possibility for the student to transmit his/her idea or be interested in everyday situations. However, Communicative Language Teaching is a signiﬁ cant tool to practise and enhance the speaking ability of students. With the development of the economy and the opportunities to study abroad, the traditional method of teaching cannot meet innovations’ demands. Therefore, most of the teachers try to ﬁ nd a method to improve the students’ speaking ability. The purpose of this article is to explain Communicative Language Teaching through reviewing different literatures and to show its effectiveness through some types of activities which can foster and enhance students’ speaking skill. in the university.They assess their speaking ability at the same level as the other three skills. Thus, it is difﬁ cult for our country’s students to pass the exam, because we always use the grammar translation method which emphasises grammar; hence, most of the students cannot talk to foreigners without hesitation. So it is an urgent problem and students must improve their speaking ability, because they cannot speak freely, even though they have learnt the language for seven or ten years. and some of its techniques. Moreover, with the help of this approach to make students more conﬁ dent. It helps to improve ﬂ uency and connect the lesson with real life situations. What is speaking? Speaking is a key point for communicating, thinking, and learning. Oral language is a considerably important learning tool. Oral language is the foundation of all language growth and, therefore, the begin of all obtaining knowledge. Speaking is at the core of other language skills because it helps to perceive them. Speaking and listening help students to learn concepts, understand the structure of the English language, and enlarge vocabulary which are extremely important components of language learning. School achivements are measured by the students’ ability to produce their ideas, to show intelligence in a pure and satisfactory type in speaking as well as writing. If Students have a powerful spoken language, they possess a greater chance of learning and use, writing and speaking are the other two productive skills necessary to be integrated in the development of effective communication. Among the four English skills, speaking seems to be the most signiﬁ cant skill which is demanded for communication . Zaremba produced a study indicating that speaking skills or communication skills were usually placed ahead of work experience, motivation, and academic credentials as criteria for new recruitment for employment [3, p. 32-34]. It is appropriate to say that in Kazakhstan we have the same situation because in order to get a job in a good company or organization you have to be interviewed by the employer to measure the level of your English. Students who study English as a foreign language usually have restrained chances to speak English outside the classroom and also limited exposure to English speakers or members of the national community. This might be one reason for teachers to provide more situations and activities for students to strengthen their speaking competence. If students are provided by deferent types of situations or often used speaking tasks, it will be a magniﬁ cent role in the enhancement of students’ ﬂ uency. Introduction and characteristics of Communicative Language Teaching. In the 1970s, there was conducted an observation by some educators and revealed that students could make accurate sentences in the classroom, but these are not used appropriately in real communication outdoors. Some other educators noticed that mastering linguistic structure is not enough for being able to communicate, due to the fact that language was fundamentally social . These points of views are agreed by the majority of our English language teachers. They also support our foreign educators opinion and in the result of some research we came to the conclusion that students who are good at grammar and vocabulary not good enough at speaking because they lack of practice. Moreover, they cannot choose appropriate utterance or functions to the context. Within a social context, language users needed to perform certain functions, such as inviting, welcoming, and refusing. Students may be acquainted with the rules of linguistic usage, but be unable to make a practice of the language. In brief, being able to communicate required more than linguistic competence; it required communicative competence knowing when and how to say what to whom. Such observations fostered a shift in the ﬁ eld in the late 1970s and early 1980s from a linguistic structure- centered approach to a Communicative Approach . Emphasizing today’s changing English Language Teaching context and the trend toward Communicative Language Teaching, Brown pays attention to the signiﬁ cance of real – life communication, producing unpracticed language performance out of the classroom, growing linguistic ﬂ uency and fostering lifelong language learning. Brown also lists some of the key features of Communicative Language Teaching as follows: “1. Classroom goals are focused on in all the components of communicative competence; they are not restricted to grammatical or linguistic competence. 2. Language teaching techniques are designed to engage learners in the pragmatic, authentic and functional use of language for meaningful purposes. Linguistic structures do not represent the central focus but rather aspects of language which enable the learner to accomplish those purposes. 3. Fluency and accuracy are seen as complementary principles underlying communicative techniques. At times, ﬂ uency may have to take on more importance than accuracy in order to keep learners meaningfully engaged in language use. 4. In the communicative classroom, students ultimately have to use the language, productively and receptively, in unrehearsed contexts” Luoma stated that “the ability to speak in a foreign language is at the very heart of what it means to be able to use a foreign language.” [7, p. 9] Implementing Communicative Language Teaching by different activities Role play and simulation. Patricia K. Tompkins states that role playing and simulation are important method for second language learners, because, thinking , creativity, motivation, development and practice of new language are encouraged . In order to experiment this technique I have been using one role play at each lesson depending on the topic. First time it was inefﬁ cient but day by day students tried to imagine and acted out differently than previous day and it made my students more creative and motivated. They memorized new vocabulary without learning it by heart, because they practised them at each lesson. Below you can see examples of role situations which I used at my lessons. Roleplay 1: calling in sick You are calling in sick from home. You’ve got a sore throat, a bad cough and a temperature. You feel guilty about phoning in sick because it means you’ll miss an important meeting. You spent most of last night preparing documents for the meeting. Offer to send your work by mail. You are the customer. You’ve been bitten by an insect of some sort. The bite is red, swollen and painful. Show it to the chemist and ask for their advice. Role play 3: at the doctor’s You are the doctor. You think that there is probably nothing seriously wrong with your patient. You do not want to prescribe any medicine if possible. Suggest simple home remedies instead. You are the boss. There is a very important meeting this morning. It’s essential that all members of staff attend. You suspect that some of your staff are taking time off sick when they don’t really need to. Roleplay 2: at the chemist You are the chemist. There has been a plague of tiger mosquitoes in your area. The local health authorities have asked chemists to report any unusual insect bites. You need to take the name, age and nationality of the patient and details about where and when they were bitten as well as a contact address or phone number. Ladousse describes simulation as complicated, durable, and inﬂ exible, but role–playing as elementary, ordinary, short and ﬂ exible. Role–playing pretends the participant is acting out and experiencing the hero image in everyday life, while simulation simulates real life situation. Some aspects of role playing are always included in simulation. Conducting such lessons I think that role play is an activity which provides fantasy or imagination to act someone or to be ourselves on a speciﬁ c occasion, creating dialogue and improvising a real world scenario. Moreover, it increases motivation, develops ﬂ uency and interaction in the target language. Donn Byrne grouped the role–play into scripted and unscripted. Scripted role play is when students are given ready made dialogue or text and act it, but unscripted, on the contrary needs the students’ imagination or fantasy to create their own Simulation is identiﬁ ed as a way of producing an appropriate communicative environment which represents the reality and students become part of it. The essential advantages of simulation include: (a) meeting students’ need for realism, a desire to “relate to life ‘out there’ beyond the classroom’s box-like walls”; (b) increasing students’ motivation; (c) getting rid of the normal teacher-student relationship in order to take control of their own destiny within the simulation, leading towards “declassrooming” the classroom; (d) facilitating the learner to deﬁ ne and deal with the target culture; (e) cutting concern levels which are innate to developing language. Role-playing and simulation are appropriate from beginner level to intermediate level. The content of activities can vary according to the level without changing the purposes such as developing ﬂ uency, encouraging interaction, constructing communicative competence and making students familiar with real life. Communicative Language Teaching classroom. It is fundamentally based on everyday life situations where students communicate in order to get information which they do not have [11, p.41]. Information gap is a type of activity which facilitates students to make suitable questions to get appropriate answer. It helps them to practise various types of questions in order to be ready to use them in the real life. Students have to work in pairs and one student has the information but the other does not. That is why they have to share their information in order to be informed. The goal of this activity is solving a problem by collecting information. In this activity the role of each partner is crucial, because if one of them cannot provide his partner with sufﬁ cient information the task will not be completed. The effectiveness of these activities derives from talking extensively in the target language . Some researchers and specialists deﬁ ned the beneﬁ ts of using information gap activity in the classes of English language. They state that information gap activities provide students with a chance to use English inside and outside the lesson and that activities have real communicative value. Furthermore, from my experience I can say that it increases conﬁ dence in speaking and it is fun and makes them happy. Also, it is really prepare them to the Information gap activity is effective from a pre-intermediate level to an upper intermediate level and activities can be complicated relative to the level. This activity can foster students’ conﬁ dence in real life. share ideas about some issues or ﬁ nd solutions. She thinks that the purpose of the discussion should be set by the teacher to be relevant to the topic of the lesson. For effective group discussion Hayriye Kayi suggests not forming large groups, because, some shy students cannot participate in discussion and always changing the members of the group in order to give them the opportunity to share their ideas with everybody. However, in my practice this activity sometimes makes my students be angry. That is why, at the lesson we created some rules as to be polite, to respect other classmates answers, to listen to the end, to keep time management, to solve or discuss some issues without offending student’s personal qualities. Discussion is appropriate at levels such as intermediate, upper intermediate and advanced. It can improve students ﬂ uency and thinking in the target language. way to teach students. Yet, it cannot answer today’s demands and I have researched this area in order to replace it with the Communicative Language Teaching method. This article is intended to solve current problems such as improving speaking in order to be competitive and to meet the demands of innovation. Having reviewed different books, journals, and websites and implementing them in my lessons I came to the conclusion that Communicative Language Teaching is the most appropriate method to solve these problems. The activities of this method can make students more conﬁ dent, improve their spoken ﬂ uency and prepare them for any situation in real life. So, covering all these qualities students of our country can pass any exams which test speaking. Being able to speak English contributes to being successful in school and later in every phase of life. Therefore, it is essential to pay great attention to teaching speaking. 1. Hayriye, Kayi. (2006). Teaching Speaking: Activities to Promote Speaking in a Second Language. University of Nevada, USA. The Internet TESOL Journal, Vol. XII.(November 2006) Retrieved from http://iteslj. 3. Zhang,Y.(2009). Reading to speak: Integrating oral communication skills. English Teaching Forum, 47 (1), 32-34. Retrieved from http://exchanges.state.gov/englishteaching/forum/archives/2009 /09-47-1.html 4. Halliday, M.A.K. (1973). Explorations in the functions of language. London: Edward Arnold. 5. Widdowson, H.G. (1978). Teaching Language as Communication. Oxford: oxford university press. Savignon, S. (1997). Communicative Competence: theory and Classroom Practice (2 edn.). New York: Mc-Graw-Hill Jersey. Prentice Hall. 7. Luoma, S. (2004). Assessing speaking (p. 9), Cambridge, Cambridge University press. 8. Patricia, K. Tompkins (1998),Role playing/simulation. The Internet TESL Journal, Vol. IV, No. 8, August 1998. Retrieved from http://iteslj.org/ 9. Ladousse, G. P. (1987). Role play. Oxford: Oxford University Press. 10. Byrne, Donn, Teaching oral English: Longman Handbooks for English Teacher. Singapore: Longman 11. Ozsevik, Z. (2010). The Use of Communicative Language Teaching (CLT): Turkish EFL Teacher’s Perspective in Implementing CLT in Turkey (p.41). MA Thesis, Graduate College of the University of Illionois at
Between July 20 and 22, 2014, the Cassini spacecraft – which has been orbiting Saturn since 2004 – tracked a system of clouds developing, then dissipating over a methane sea on Saturn’s large moon, Titan. Earthly scientists call this alien northern sea on Titan by the name Ligeia Mare. The scientists tracked the clouds, which are also made of methane, during this two-day period and made measurements of cloud motions revealing wind speeds of about 7 to 10 miles per hour (3 to 4.5 meters per second). NASA says that: This renewed weather activity, considered overdue by researchers, could finally signal the onset of summer storms that atmospheric models have long predicted. For several years after Cassini’s 2004 arrival in the Saturn system, scientists frequently observed cloud activity near Titan’s south pole, which was experiencing late summer at the time. Clouds continued to be observed as spring came to Titan’s northern hemisphere. But since a huge storm swept across the icy moon’s low latitudes in late 2010, only a few small clouds have been observed anywhere on the icy moon. The lack of cloud activity has surprised researchers, as computer simulations of Titan’s atmospheric circulation predicted that clouds would increase in the north as summer approached, bringing increasingly warm temperatures to the atmosphere there. Elizabeth Turtle, a Cassini imaging team associate at Johns Hopkins in Maryland, said: We’re eager to find out if the clouds’ appearance signals the beginning of summer weather patterns, or if it is an isolated occurrence. Also, how are the clouds related to the seas? Did Cassini just happen catch them over the seas, or do they form there preferentially? A year on Titan lasts about 30 Earth-years. Thus each Titan season lasts about seven years. NASA says that observing seasonal changes on Titan will continue to be a major goal for the Cassini mission as summer comes to Titan’s north and the southern latitudes fall into winter darkness. Bottom line: NASA has released an animation of methane clouds moving above a hydrocarbon sea on Saturn’s large moon, Titan. The Cassini spacecraft acquired the images for the animation on July 20 and 22, 2014. Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
Chapter 9, part 3 Pests Attacking Man and His Pets - General Morphology of Adults - The Flea Life Cycle - Reaction to Flea Bites - Disease Transmission - Flea Species List - Control of Fleas Of the approximately 1,600 described species of fleas in the world, 95% occur on mammals and 50% on birds. Most species attacking man in the United States have been placed in the family Pulicidae (order Siphonaptera). Because of their abundance, world-wide distribution, irritating bites, and ability to transmit disease, fleas are among the principal medically important groups of arthropods. General Morphology of Adults. Fleas are small, black to brownish-black insects, with complete metamorphosis. They are wingless, having lost their wings in the course of their evolutionary development. Adult fleas are 1 to 4 mm long, depending on the species, and are laterally compressed. They have stout, spiny legs, adapted for leaping, and short, 3-jointed, clubbed antennae that fit into depressions along the sides of the head. Fleas have piercing-sucking mouthparts (figure 46, C, chapter 4), the principal elements of which are the grooved labrum and a pair of sharp, swordshaped mandibles. The concave inner sides of the mandibles, together with the labrum, form the sucking channel (Ewing and Fox, 1943). In some species, a conspicuous transverse row of spines is located just above the mouthparts, and is called the genal comb or ctenidium. In others, the pronotum bears a transverse row of heavy spines called the pronotal comb. When flea specimens are "cleared" in lactic acid for microscopic examination, the combs show up prominently, and can be used to identify species with the aid of low magnification. Figure 302 shows that the cat, dog, mouse, and rabbit fleas have both genal and pronotal combs. Certain species that infest rodents have the pronotal but not the genal comb, and the human, oriental rat, and sticktight fleas lack both combs. It has long been assumed that the combs or ctenidia assist fleas in locomotion through fur, hair, and feathers, but this is apparently not the case; locomotion is facilitated by the strong setae on the legs, projecting almost. at right angles. The combs serve to make dislodgement or capture by the host more difficult. They are admirably adapted to resist a backward pull, and so must have a considerable survival value (Humphries, 1966). The Flea Life Cycle. A female flea will lay 4 to 8 eggs after each blood meal, and can usually lay several hundred eggs during her adult life. The smooth, oval or rounded, light-colored eggs (figure 303, C), about 0.5 mm long, are deposited on, but not firmly attached to, the body, the bedding, or the nest of the host. Although they are a little sticky, those laid on the host's body may fall or be brushed off. This accounts for their being found in crevices in the floor, under the edges of carpeting, in sofas, or in cat or dog boxes, kennels, etc., where they usually hatch in 10 days or less. The small, hairy, wormlike larvae, (figure 303, B) are whitish, with a distinct, brownish head, and do not have eyes or legs. They have 3 thoracic and 10 abdominal segments, with a single row of bristles around each segment. The larvae are about 1.5 mm long when they emerge, finally becoming about 5 mm long. They move forward by using their backward-projecting bristles and a pair of hooked, chitinous processes located at the end of the abdomen by which they can obtain purchase on a surface. When disturbed, they may "flip" in circles to escape. The larvae of some species require dried blood for food, but others do not. Those that do not need blood can feed on the many kinds of organic debris that are present in the crevices in which the eggs commonly hatch. They also feed on their own cast skins. They require high humidity. Within a week to several months, the larvae grow through 3 instars, then spin a pupal cocoon (figure 303, D) covered with grains of sand, dust, or organic debris, in which they are quite effectively camouflaged in their natural surroundings. The pupae are initially white (figure 303, E), but they change to brownish before the adults emerge. In the pupa, the appendages are not closely pressed to the body, and it has: the general shape and characteristics of the adult. Under favorable conditions, the adult emerges in a week or two, but under adverse conditions, the pupal period may be prolonged to as much as a year. The adult may remain in the cocoon for a long time until vibrations indicating the presence of a possible host stimulate it to emerge and become active. The potentially long pupal stage, besides the fact that adult fleas can live without food for remarkably long periods, accounts for the fact that people may enter a house after it has been unoccupied by humans or pets for months, yet be rapidly and severely attacked by fleas. Depending on the species and weather conditions, 2 or 3 weeks to as many months, and rarely as long as 2 years, are required for many species of fleas to complete a life cycle. Some people react severely to flea bites, while others hardly notice them. The famous entomologist Karl von Frisch, while on one of his trips to the Naples Zoological Station, shared a room with a friend because that particular room gave them "a marvelous view over the blue Gulf to the lovely contours of Capri." When they found that it was flea-infested, before going to bed they walked barefoot back and forth in the room, and then took off their "nightshirts" and removed the fleas. Von Frisch averaged 4 or 5 per night, and his friend, 30 or 40. However, the friend was annoyed only by their crawling, whereas von Frisch got a big blister from every bite. He pointed out that it would take more than 1.5 million fleas to produce a full-sized drop of the tiny amount of saliva injected in 1 bite, but that this would be enough "to set all the people in Hamburg scratching" (von Frisch, 1960). (See comment in the next paragraph.) Fleas most often bite people about the legs and ankles, and there are usually 2 or 3 bites in a row. The bites are felt immediately, but tend to become increasingly irritating, and are frequently sore for as much as a week. Flea bites may vary in their effects, from a transient wheal to prolonged symptoms that last for years, depending on the sensitivity of the victim. Children less than 10 years old were found to be more sensitive to the bites than older persons (Hudson et al., 1960b). The insects inject a hemorrhagic saliva that can cause severe itching, and repeated bites may produce a generalized rash. A small, red spot usually appears where the flea's mandibles have penetrated the skin. The spot is surrounded by a red halo, but there is never much swelling. Some relief from the itching can be obtained by applying cooling preparations, such as. carbolated vaseline, menthol, camphor, or calamine solution, or by placing a piece of ice on the affected area. For people who suffer severe allergic reactions, antigens are available that are sufficiently effective to cause the immunized person to be subsequently unaware of flea bites. The most serious indictment against fleas is their ability to transmit disease organisms. This ability is enhanced by their promiscuous feeding habits; they move from one host species to another. For example, the cat flea, Ctenocephalides felis, readily attacks humans, dogs, rats, opossums, raccoons, and foxes. The human flea, Pulex irritans, can be found on dogs, rats, pigs, mice, skunks, badgers, deer, foxes, coyotes, prairie dogs, ground squirrels, and burrowing owls. The species normally found on rats and ground squirrels also bite man. Probably the most dreadful calamity in all human history was the "Black Death," a series of plagues of the Middle Ages, particularly in the fourteenth century. Although not known at the time, the highly contagious disease was caused by a bacillus, Yersinia pestis (= Pasteurella), carried primarily by rats and transmitted by the fleas they harbored. The disease caused swellings of the lymph glands and subcutaneous hemorrhages that turned black. The plague first struck in Asia, and then spread to Russia, Persia, Turkey, North Africa, and Europe. The Encyclopedia Britannica estimates that one-third of the world's people perished. The most dangerous forms of plague are bubonic, septicemic, and pneumonic. Two types are named for the parts of the body infected. Bubonic plague, confined initially to lymphatic glands (buboes), is not so dangerous as the septicemic, and especially the pneumonic, phases, which are rapidly spread from person to person by airborne infection (Dubos and Hirsch, 1965). Bubonic plague is no longer a major scourge of mankind, but only because we now know how it is transmitted, and therefore how to prevent it. War and dislocation can still increase its potential, but not as in past centuries. The World Health Organization reported 1,318 cases of plague in 1968 and 864 in 1969, the majority from Vietnam, Treatment of the disease is quite effective with modern antibiotics. However, it can sometimes be dangerous, even with early diagnosis and treatment. The oriental rat flea, Xenopsylla cheopis, is the most important vector of the plague bacillus, Yersinia pestis, from rat to man but at least 29 other species of fleas can transit the disease including the northern rat flea, Nosopsyllus fasciatus; the mouse flea, Leptopsylla segnis; the dog flea, Ctenocephalides canis; the cat flea, C. felis; and the human flea, Pulex irritans. Plague is transmitted while the infected flea is feeding, by regurgitation of the bacillus from the flea's alimentary tract through the proboscis into the new host. Yersinia pestis is rapidly eliminated from the proventriculus of the oriental rat flea when the mean monthly ambient temperature exceeds 28 °C (82 °F), and plague epidemics decline with the advent of hot weather (Cavanaugh, 1971). "Sylvatic" or "endemic" is the designation used for the plague in wild rodents. Under certain ecological conditions in vacated squirrel burrows, fleas may continue to harbor the plague bacilli for many months, providing a reservoir for the infection. Fleas are particularly suitable for this purpose because of their remarkable longevity, for they can survive more than 6 months, even without food. Sylvatic plague occurs in many parts of the world, remaining somewhat localized in each area. A group of rodents maintains the infection, and if domiciliary rats or mice come in contact with such a focus of infection, the disease may be carried to human habitations and human cases may result. Likewise, if humans enter sylvatic plague territory, they may become infected. Ground squirrels and chipmunks have been shown to be reservoirs for the plague bacillus in California. In the case of sylvatic plague, a person is more likely to become infected by contact with sick or dead rodents than by flea transmission. Since 1925, all the known cases of plague in the United States have been associated with wild rodents and the fleas that infested them. The United States Public Health Service reported 36 cases of human plague during the 6-year period 1965-1970. Twelve of these cases were reported in 1970. Eight cases have been reported in California since 1940. Areas in California where rodents are periodically killed by plague extend from the northeastern part of the state through the Sierra Nevada to the Tehachapis, and also in the coastal areas between San Francisco and Ventura County. People are warned not to handle sick or dead animals. Sometimes, a sudden widespread increase (epizootic) of a disease will occur among such rodents, and the chance for human infection will increase greatly. During epizootics, control has been attempted by placing bait boxes containing 10% DDT and peanut butter at 500-ft (150-m) intervals in the infested area. The rodents that enter a box to feed pick up not only enough insecticide to kill the fleas on them, but also the fleas living in their nests or burrows. (Anonymous, 1970a). The oriental rat flea is also the principal vector of murine or endemic typhus that may be transmitted from rats to man. This disease is caused by the microorganism Rickettsia mooseri, and is widespread in rats and other rodents. The principal mode of transmission is believed to be by rubbing or scratching infected flea feces into wounds made by their bites. Murine typhus should not be confused with the more serious epidemic typhus, which has caused the deaths of millions of persons, but is transmitted by lice. The fatality rate for murine typhus, on the other hand, is only about 2%. In the United States, the disease is often confused with tickborne Rocky Mountain spotted fever, both diseases being characterized by rash and fever. However, Rocky Mountain spotted fever usually occurs during the spring and early summer, while murine typhus occurs in late summer and fall. Murine typhus cases in the United States dropped sharply from 5,193 cases in 1945, through a combination of rat control and insecticide dust for fleas. Also, new broad-spectrum antibiotics have been successful in the treatment of clinical cases of the disease (Pratt and Wiseman, 1962). In California, murine typhus has remained endemic only in the 5 southern counties since 1919, when the first cases were recognized. In the 30 years from 1920 to 1949, there were 487 cases and 21 deaths from the disease. In the 20 years from 1950 through 1969, there were 79 cases and no deaths. Since 1960, there have been about 1.5 cases per year (CPHS, 1971). Cats as Transmitters. About 75% of the 28 to 52 cases of murine typhus per year that occurred in the United States since 1945 were reported from Texas, particularly in 3 southern counties in which the disease was epidemic, and in some instances under circumstances in which the usual method of spread from rat to rat flea to man did not seem to occur. Prompted by this fact, the possible role of the domestic cat in the transmission of murine typhus to man was investigated. Rickettsia mooseri had been found in cat fleas, Ctenocephalides felis, in nature (Irons et al., 1944), and it was assumed that the cat fleas obtained the rickettsiae from their normal source, the rat. There is much circumstantial evidence that most of the murine typhus in southern Texas is transmitted via flea-infested cats or from flea-infested grass. (In southern Texas, grass is often so heavily infested with cat fleas that they are locally known as "grass fleas.") The greatest incidence of murine typhus in southern Texas has been noted to be in women and children, who spent more time at home where most of the illnesses were contracted (Older, 1970). The investigation in southern Texas confirmed the conclusion arrived at by Irons et al. (1944) that at least 5 cases of murine typhus in Austin in 1942, including 1 laboratory infection, were probably acquired through the agency of cat fleas harbored by kittens carried away from a feed store. In endemic areas, feed stores were said to be particularly serious foci of typhus. Likewise in southern California, where 34 separate outbreaks of murine typhus were recorded from 1952 to 1969, 21 were in families that owned cats or had frequent contact with them. Again, as in southern Texas, most cases occurred among housewives and children. Seven outbreaks were intimately associated with either dogs, cats, opossums, or skunks, and 2 with rats. With greatly improved rat and flea control, there has been a shift in the incidence of murine typhus in man from central Los Angeles to foothill and orchard areas in eastern Los Angeles and Orange counties. Opossums in such areas are heavily infested with fleas, and are suspected of being responsible for some of the sporadic cases of typhus in man (Adams et al., 1970). Fleas, particularly dog and cat fleas, can serve as intermediate hosts for the dog tapeworm, Dipylidium caninum (L.), and the rodent tapeworm, Hymenolepis diminuta (Rudolphi), which occasionally attack humans, particularly very young children. - cat flea, Ctenocephalides felis (Bouché). and dog flea, C. canis (Curtis) (Pulicidae) - human flea, Pulex irritans L. (Pulicidae.) - oriental rat flea, Xenopsylla cheopis (Rothschild) (Pulicidae) - rabbit flea, Cediopsylla simplex (Baker) (Pulicidae) - sticktight flea, Echidnophaga gallinacea (Westwood) (Pulicidae) - chigoe, Tunga penetrans (L.) (Tungidae) - ground squirrel flea, Diamanus montanus (Baker) (Ceratophyllidae) - northern rat flea, Nosopsyllus fasciatus (Bosc) (Ceratophyllidae) - squirrel flea, Orchopeas howardii (Baker) (Ceratophyllidae) - mouse flea, Leptopsylla segnis (Schönherr) (Leptopsyllidae) - cat flea, Ctenocephalides felis (Bouché). and dog flea, C. canis (Curtis) (Pulicidae) These 2 fleas, particularly the former, are the most common species found in and around homes. They are most abundant in summer, and seem to be especially numerous when homes are reoccupied after the residents have been gone for a few weeks. In California, these fleas are much more abundant in the relatively humid coastal areas than in the more arid ones farther inland, and are particularly numerous during years of greatest rainfall and humidity. The cat and dog fleas are so similar in appearance and biology that for practical purposes they can be described under the same heading. A few minor differences are noted in the following text. Description. The female (figure 303, A) is 2.5 mm long, and the male is slightly smaller. The head of the female cat flea is twice as long as high when seen from the side, while that of the female dog flea as less than twice as long as high. In both species, the genal comb consists of 8 pairs of spines, and the pronotal comb also consists of 8 pairs (figure 302). With the aid of low magnification, it can be determined that the first 2 anterior spines of the genal comb of the cat flea are about equal in length, while the first spine is distinctly shorter in the dog flea (Ewing and Fox, 1943; Pratt and Wiseman, 1962). The larvae of both species (figure 303, B) are nearly twice as long as the adults. They feed on particles of dry blood, excrement, and various organic substances collected in corners and crevices in the infested premises. When infestations are very heavy, the accumulations of grayish larvae and white eggs give the sleeping quarters of cats and dogs a "salt-and-pepper" appearance that easily identifies the infestation. How Infestations Are Spread. Particularly in warm, humid areas, the exclusion of cats and dogs, or their proper management, is necessary to prevent flea infestations. Residential premises are sometimes so heavily infested that cats will leave to seek relief, and will carry the infestation to an uninfested home. If an infested stray cat has kittens under or near an uninfested home, the appearance of fleas within the house is very likely to follow. Fleas often also become established in the lawns of heavily infested residences. Fleas can jump vertically for 5 or 6 inches (about 15 cm), and can attach themselves to skin or clothing. Some pest control operators avoid being bitten by spraying insecticide onto their clothing. In addition to cats, dogs, and humans, many animals, including the opossum, are attacked by cat fleas and dog fleas. Indigenous to the southeastern United States, opossums are now found throughout the country. They were introduced into California when some of the animals kept as pets escaped in San Jose in 1910, and they are now abundant throughout the state. When people live near wooded areas or stream courses, or where trees and shrubs are abundant, they may have opossums in the attics, wall voids, crawl spaces, or basements of their homes. These animals can then be sources of infestation. human flea, Pulex irritans L. (Pulicidae.) The human flea is found all over the world. Besides man, it infests cats, dogs, and many other domestic animals, particularly the pig. It breeds in profusion in pigsties, and people working in them can readily pick up large numbers of fleas and start infestations in their homes. The human flea is usually the most important species in farm areas. While the bites of the cat flea tend to be concentrated on the lower parts of the legs, those of the human flea may be generally distributed over the body (Keh and Barnes, 1961). Description. The human flea lacks the genal and pronotal combs characteristic of the cat flea and dog flea, and may be distinguished from the oriental rat flea by having its ocular bristle inserted beneath the eye instead of in front of it, as it is in the latter species (figure 302). oriental rat flea, Xenopsylla cheopis (Rothschild) (Pulicidae) Along with its favored host, the rat, this species (figure 302) is cosmopolitan. It is one of the most abundant fleas in the southern states and southern California., and is the most important vector of bubonic plague and murine typhus. Fortunately, it is not so commonly found in human habitations as are some other fleas, but it has been reported to bite people in buildings. It also infests cottontail rabbits and ground squirrels. High relative humidity (70% or greater) and temperatures of 65 to 80 °F (18 to 27 °C) are favorable conditions for hatching of rat flea eggs. Although a temperature of 40 °F (4 °C) was reported to be fatal to the oriental rat flea the temperature would seldom be that low in the warm nests of rats. The larval period may be 12 to 84 days, the pupal period in the cocoon, 7 to 182 days, and adults may live for 100 days (Hubbard, 1947). rabbit flea, Cediopsylla simplex (Baker) (Pulicidae) This species can be distinguished from the cat and dog fleas by the almost vertical position of its genal comb and the rounded ends of the spines, compared with the horizontal position and sharp points found in the latter (figure 302). This is an eastern species, and is known to bite hunters and hikers. Similar species occur in the western region. sticktight flea, Echidnophaga gallinacea (Westwood) (Pulicidae) This is one of the smallest fleas. The females are 1 to 1.5 mm long, and the males are less than 1 mm. Sticktight fleas are most abundant in the southern states. They infest wild birds, some of which, such as Brewer's blackbird, house sparrow, and bobwhite quail, may be expected to be effective dispersal agents (Stewart, 1932). Nevertheless, sticktight fleas are said to be rare in the Northwest, where these birds are plentiful. Although sticktight fleas were formerly sometimes considered to be severe pests in California, they are now rarely seen, apparently having been decimated by the more effective insecticides used in the treatment of poultry in recent decades (R. N. Hawthorne, personal communication). The adult flea attaches itself firmly to the head and neck of domestic fowls, often causing ulcers. The female oviposits in the ulcers, and the larvae drop to the ground and feed on organic matter. Sticktight fleas (figure 302) can become abundant in poultry yards and adjacent buildings. Besides fowls, they will attack man, cats, dogs, rats, rabbits, ground squirrels, horses, and many other mammals. They are potential transmitters of plague and murine typhus, but the habit of the females of remaining fastened to a single, host most of their lives greatly decreases their importance in this respect. The western hen flea, Ceratophyllus niger Fox (Ceratophyllidae), is larger than the sticktight flea, and attaches itself only briefly while feeding. It breeds primarily in fowl droppings. Besides fowls, it readily attacks humans, cats, and dogs. chigoe, Tunga penetrans (L.) (Tungidae) The chigoe flea, also known as "jigger," "chigger," "chigu," or "sand flea," is said to have inspired the sailor's oath, "I'll be jiggered!" This flea should not be confused with the true "chigger," which is a species of mite (Trombicula alfreddugesi). In fact, the chigoe flea is not definitely known to have become established in the United States. It is a tiny, burrowing flea, found in the tropical and subtropical regions of North and South America, the West Indies, and Africa. It is reddish brown, and about 1 mm long, although the gravid female may become as large as a "small pea." The fertilized female slashes the skin with her mouthparts, then inserts her head and body until only the last 2 abdominal segments are exposed. There she feeds, and continues to oviposit. The eggs hatch in 3 or 4 days, and the entire life cycle requires about 17 days (Hubbard, 1947). The chigoe usually attacks humans between the toes or under the toenails, becomes engorged with blood, causes great pain, and may produce inflammation and localized ulcers. Tetanus and gangrene may result from secondary infections. Autoamputation of toes has been recorded. People should avoid walking in their bare feet where these fleas are known to occur. ground squirrel flea, Diamanus montanus (Baker) (Ceratophyllidae) This flea is dark brown, medium-sized, and has very long labial palpi (figure 302). It is found on ground squirrels from Nebraska and Texas to the Pacific Coast. When 132 California ground squirrels (Citellus beecheyi) were combed, 4,371 D. montanus and 226 specimens of another flea, Hoplopsyllus anomalus (Baker), were obtained (McCoy, 1909). Both species are vectors of plague. In laboratory tests, H. anomalus proved to be about half as efficient as the northern rat flea (described next) as a plague vector (Hubbard, 1947). northern rat flea, Nosopsyllus fasciatus (Bosc) (Ceratophyllidae) This species is found on domestic rats and house mice throughout North America and Europe, but is most common in temperate regions where plague is not a severe problem. It may be important in transmitting plague organisms among rats, and has occasionally been taken from wild rodents. In experimental tests, N. fasciatus transmitted endemic typhus from rat to rat (Dyer et al., 1932). This flea and Xenopsylla cheopis are known to be intermediate hosts for Hymenolepis diminuta, the common tapeworm of rats and mice, which is rarely found in man. Nosopsyllus fasciatus and Diamanus montanus both lack the genal comb. The labial palps of the latter extend beyond the trochanter of the first leg, while those of N. fasciatus do not (figure 302). The pronotal comb has 18 to 20 spines. squirrel flea, Orchopeas howardii (Baker) (Ceratophyllidae) The squirrel flea is found throughout the United States wherever gray squirrels (Sciurus griseus) occur. It is frequently taken from the red squirrel and flying squirrel when the ranges of these hosts overlap that of the gray squirrel. If a gray squirrel builds its nest in an attic and is later killed or excluded, the fleas that breed in the nest material may escape and invade other parts of the house. Attic nests of these squirrels should be removed and insecticides should be applied to their sites (Pratt and Wiseman, 1962). The female's head is well rounded, while the male's is flattened on top. The genal row of 3 bristles is at a level with the top of the eye, and the middle bristle is about half as long as the outer one (Hubbard, 1947). (See also, figure 302.) mouse flea, Leptopsylla segnis (Schönherr) (Leptopsyllidae) The mouse flea can be distinguished from other common fleas having both genal and pronotal combs by its genal comb having only 4 spines (figure 302). It is most commonly found on domestic rats, and less often on the house mouse, Mus musculus. This flea is common in Europe, and is most abundant in the United States along the east and west coasts near the original ports of entry. It is scarce in inland areas and during the summer, for it thrives best in cool weather. Although it can be infected with plague in the laboratory and has been found to be naturally infected with murine typhus in China, it is considered to be a poor vector of those diseases (Pratt and Wiseman, 1962). Fleas may occur on beaches, particularly if there are nearby residences. People using beaches may be bitten by these fleas or by stable flies (Stomoxys calcitrans), which can often be found in piles of seaweed. Small amphipod crustaceans (Orchestia), known as "sand fleas," also found under beached seaweed, are often blamed for bites, but they are in fact completely harmless. Successful flea control must include not only the treatment of infested animals, but also thorough treatment of the entire infested premises. Pets can, of course, be sent to the veterinarian for treatment. In that case, they should not be allowed to return until the fleas have been controlled in the infested source area. Even if both pets and premises are free of fleas, the pets can become reinfested if they are allowed to roam about in infested areas and associate with infested animals in the neighborhood. Other animals from outside sources that enter the treated premises can also cause reinfestation. Treatment of Pets. Dusts are safer than sprays to use for treating pets, because no solvent is present to carry the toxicant into the skin. The safest insecticides are the botanicals (pyrethrum or rotenone). Some pyrethrum dusts may merely paralyze the fleas, allowing them to recover later. To prevent recovery and reinfestation, paralyzed fleas should be combed out of the pet's fur into a piece of newspaper and burned. Several brands of 1% and even 2% pyrethrins, plus 10% piperonyl butoxide (a synergist), and substantial quantities of base oil, incorporated into silica aerogels, are readily available. These preparations have extremely high insecticidal potency, and good results have been reported when they were thoroughly applied. Another relatively safe insecticide is malathion; 3% malathion dust was used on a female cat and 3 successive litters of kittens with no apparent harm to the animals. Each treatment controlled the fleas for 7 to 10 days (Pratt and Wiseman, 1962). Insecticide dusts should be applied with a shaker, or be rubbed into the fur by hand, keeping the dust out of the animal's eyes, nostrils, and mouth. Treatment should be particularly thorough around the ears and beneath the forelegs. As much as 1 oz (30 cc) of dust is required for a large dog. Particularly when the dust contains pyrethrum, the fleas move about actively for a while, causing the animal some discomfort. The following insecticides have been suggested for flea control on pets: (1) carbaryl dip or wash 0.5%, or dust 2 to 5%; (2) coumaphos dip 0.2 to 0.5%, spray 1%, or dust 0.5% (the coumaphos dust also contains 1% trichlorfon); (3) lindane dust 1% (neither lindane nor coumaphos should be used on cats or on dogs under 2 months old); (4) malathion dip 0.25%, spray 0.5%, or dust 4 to 5%; (5) pyrethrum spray 0.2% plus 2% synergist, or dust 1 %; and (6) rotenone dust 1 % (Anonymous, 1970a). Ronnel as a 0.25% solution can also be used to dip and sponge dogs and cats. Mallis (1969) warned against the use of rotenone on canaries, for it might cause them to contract pneumonia. He suggested a powder containing pyrethrum only. Pigs are also known to be particularly susceptible to rotenone (Anonymous, 1970a). Dips or washes should be used under the supervision of a veterinarian. He can also treat dogs and cats by oral administration of 25 mg of ronnel per lb (0.45 kg) of body weight of the animal every other day, or trichlorfon tablets at 34 mg per lb of body weight twice weekly. Flea Collars. Registration has been obtained for dichlorvos-impregnated flea collars for dogs (except whippets and greyhounds), and cats (except Persian), and the collars have been effective (CDC, 1972). Some animals suffer an adverse reaction, initially indicated by a reddening of the skin under the collar. The skin under the collar should be examined frequently, particularly when the collar is being used for the first time. For dogs, the collar should be loosely fastened, to allow for good separation between collar and skin. For cats, it must be fitted tightly, to avoid possible strangulation when the animal is climbing. To prevent deterioration of the insecticide, the collar should not be allowed to become wet. If the skin under the collar does become irritated, it sometimes takes weeks or even months to heal. In most cases, simply removing the collar and topically applying a medicated ointment to the affected area will be all that is needed. Occasionally, a person may be so hypersensitive to dichlorvos that the handling of the flea collar will cause dermatitis in the contacted areas of skin (Anonymous, 1970h). Control of fleas with no risk of dermatitis and with no other clinical effects appeared to be possible when disks of 20% dichlorvos in plastic containers with ventilation holes were hung on dog collars. These plastic containers resulted in complete control of fleas within 120 hours on all dogs tested. Ticks were not killed, but dogs initially without them remained free for the 92-day period of the test (Quick, 1971). Treatment of Premises. Fleas are most concentrated in and around kennels or other places where animals sleep, and in rugs or under porches where they rest. Infested animal bedding should be burned, or else laundered in hot, soapy water. It should not be left unlaundered for long periods while the animals are away, such as during vacations. Sometimes accumulations of lint and dust contain flea eggs, larvae, and pupae that can be removed with a vacuum cleaner. The cleaned area can then be sprayed with 0.5% lindane or, if the fleas happen to be resistant to organochlorine insecticides, 2% malathion or ronnel or 0.5% diazinon may be used. The relatively new insecticide Gardonals, of very low mammalian toxicity, is said to be effective for flea control. Baseboards, moldings, bed frames, floor areas, and rugs should be lightly sprayed. If oil-base spray contacts asphalt tile, it should be wiped up immediately. The author prefers oil-base sprays, for a very fine mist can be generated and there is less chance of staining, but open flames should be avoided. A fine, light mist with oil-base is particularly desirable for treating upholstered furniture. When an area is not easily accessible or where it is not practicable to remove rubbish and clutter, a 0.2% spray of dichlorvos may be desirable because of its fuming action. Pest control operators sometimes add a small amount of dichlorvos to the residual spray. Insecticide dusts are suggested for the treatment of inaccessible places where spraying may be difficult or impossible. Silica aerogel dust (Dri-die¨ 67) is useful for the treatment of attics and wall voids because it can be so easily and uniformly blown throughout any enclosed area. Because it is inorganic, silica aerogel remains effective indefinitely. The homeowner should make the attic, wall voids, and underarea (crawl space) rodentproof before treatment. Also, stray cats, dogs, and other animals should be kept out of the subfloor area, for they may infest it with fleas. The author has rapidly and effectively treated a home by allowing a fog from a Hi-Fog machine (figure 21, chapter 3) to drift lightly over the entire area inside the house-over carpeting, under beds, sofas, and other furniture, and into closets, using 2% malathion or 20% ronnel. Using a hose attachment sprayer, the entire yard area was sprayed with 1 % diazinon emulsion, with special attention to the lawn. Fleas were found to be particularly abundant around garbage cans. Most modern insecticides are remarkably effective against fleas, and failure to control them can usually be attributed to faulty application. The ticks constitute the superfamily Ixodoidea of the order Acarina, which includes the mites, but their larger size and leathery cuticle distinguish the ticks from the mites. The Acarina can be distinguished from insects by the head, thorax, and abdomen being fused together, by the absence of antennae, and by the nymphs and adults having 4 pairs of legs. However, the larvae have 3 pairs of legs, as do full-grown insects. There are 2 families of ticks: the "soft" or "softbacked" ticks (Argasidae), with about 20 species in the United States, and the "hard" ticks (Ixodidae), with about 55 species. The latter are of greater economic importance. Description and Biology. Instead of a true head, ticks have a capitulum (see figure 305, for hard ticks). This consists of a basal portion, the basis capituli, to which the hypostome, the chelicerae, and the 4-segmented palps are attached. The hypostome is not only a piercing organ, but also possesses rows of backward-projecting spines that anchor the tick to the skin of its host. The insertion of the hypostome is facilitated by the chelicerae, that serve as cutting agents. At the extremity of each chelicera is a pair of digits, used to lacerate the skin of the host (figure 305). Both male and female ticks are bloodsuckers. After engorgement, fertilization takes place. The male then dies, and the female drops to the ground and seeks a sheltered place for oviposition. After the period of several days required for the eggs to develop, she lays her eggs and also dies. For their first blood meal, the 6-legged tick larvae or "seed ticks" must depend on chance meetings with suitable hosts, so as might be expected, they are able to live for long periods without food. In nature, the tendency of ticks to congregate along animal paths and roads, drawn by the scent left by passing animals, increases their chances of finding hosts. After engorging, they molt and become 8-legged nymphs. The "soft ticks" may have several nymphal instars, and may have to endure a period of prolonged starvation each time they await a new host, but the "hard ticks" have only 1 nymphal instar. In either case, the mature nymphs may have to endure months of starvation before finding a suitable host upon which to feed, molt, and become adult. The adult leaves the host to lay eggs on the ground. Upon emerging from the eggs, the larvae commonly climb up on grasses or shrubs in order to be more readily contacted by passing animals. Economic Importance. Few tick species are ever found in the home, but they may infest dogs and are important pests of livestock. Tick bites can cause great discomfort to humans. They remain attached for long periods of feeding, and therefore have the opportunity to inject large amounts of their venom, causing symptoms ranging from mild irritation to paralysis. If not soon removed, some species (wood ticks) can cause a form of paralysis known as "tick paralysis." Species of Ornithodoros - Ornithodoros hermsi Wheeler, Herms, and Meyer - Pajaroello, Ornithodoros coriaceus Koch - The Genus Argas - Fowl Tick, Argas persicus (Oken) The "soft" or "softbacked" ticks are 4 to 12 mm long, have a leathery, wrinkled, granulated integument, and no dorsal shield. The capitulum and mouthparts are ventral, whereas they project anteriorly in the "hard" ticks. The pedipalpi are leglike, and the 4 segments are equal in length, whereas in the hard ticks the fourth segment is very small. The spiracles are situated on the sides of the body above the third and fourth pairs of legs. There is no marked morphological difference between the sexes. Most adult soft ticks are long-lived, up to several years, the females laying eggs periodically - 20 to 50 after each blood meal. The frequency of feeding depends on the number of hosts that pass by. Among the soft ticks, only species of the genera Ornithodoros and Argas are important as vectors of disease. Argas spp. are important poultry parasites, but seldom attack man. Ornithodoros can be distinguished by the rounded sides of the body, in contrast to the distinct marginal border of Argas, which is always visible, even when the tick is fully engorged. Species of Ornithodoros Ornithodoros spp. are argasids that are perhaps best known through the dreaded African relapsing fever tick O. moubata (Murray), that hides in the dust and thatch of native huts and engorges rapidly on the blood of the inhabitants, transmitting an endemic relapsing fever caused by many different strains of a spirochete, Borrelia recurrentis. In the United States, tick-transmitted endemic relapsing fever was first reported in central Texas (Weller and Graham, 1930). Since then, it has been reported in widely scattered areas in the western states. Man is infected by the bite or coxal fluid of infected argasid ticks, principally Ornithodoros turicata and O. hermsi, in the United States (CPHS, 1971). Aside from the fact that Ornithodoros includes species that are vectors of relapsing fever, the genus is important because it includes several species that inflict painful bites. Ornithodoros hermsi Wheeler, Herms, and Meyer This species is the most serious vector of relapsing fever in the mountain areas of California and some other western states. Ornithodoros hermsi is found at elevations of 5,000 ft (1,500 m) and higher, while O. turicata Dugès and O. parkeri Cooley are found at lower elevations, but are not serious problems. The female of O. hermsi is 5 to 6 mm long and 3 to 4 mm wide. The male is slightly smaller, but is similar in appearance. Unengorged ticks are light sandy in color. Freshly engorged specimens are dull, deep garnet, with a grayish-blue tint a few days after feeding. Absence of food greatly prolongs the life cycle. The larvae may live as long as 95 days without food, the nymphs even longer, and the adults more than 7 months. With occasional feeding, they have been kept alive in a pillbox for over 4 years (Herms, 1939). The duration of the life cycle varies from 202 to 314 days at 30 °C (86 °F) to 364 to 602 days at 21 °C (70 °F) (Pratt and Littig, 1962). Ornithodoros turicata and O. talaje (Guérin-Meneville) transmit relapsing fever in southern areas, between Florida and California and northward to Kansas, Colorado, and Utah, and O. parkeri transmits the disease in the northwestern area. Relapsing Fever. Relapsing fever is caused by host-specific spirochetes (slender, spirally undulating bacteria). The disease is characterized by chills, fever, sweating, generalized pains, and usually nausea, vomiting, and headache. Ticks not only remain infective for life, but pass the spirochetes to their offspring through the egg. Not only ticks, but also their rodent hosts, serve as reservoirs for the spirochetes. Ornithodoros hermsi transmits the spirochete Borrelia hermsi and O. parkeri transmits B. parkeri without crossinfections between the 2 species (Davis, 1939, 1948; Pratt and Littig, 1962). Mountain cabins in areas where tickborne relapsing fever occurs should be rodent-proofed to exclude small rodents. Avoid soiling the fingers with the blood of chipmunks or squirrels. Infection can take place by contamination of a wound in the skin, although it is known that Ornithodoros hermsi, O. turicata, and O. parkeri definitely infect by their bites (Hunter et al., 1960). Pajaroello, Ornithodoros coriaceus Koch A considerable number of soft ticks produce local or systemic disturbances by their bites alone - notably, some species of Ornithodoros, including O. turicata, just mentioned. In the more mountainous coastal counties of California, the pajaroello, O. coriaceus, is a much-feared tick of this type, attacking deer, cattle, and man. It has also been reported in South America and Mexico. It is especially abundant in deer beds. Description. The pajaroello is a large tick, leathery, rough, and granulated (figure 304), and the whole surface, above and below, is a dirty yellowish-earthy color, and has rusty-red spots irregularly distributed (plate VIII, 6). The capitulum and palps are light yellow, and the legs are gray-brown. The unengorged tick is 10 to 12 mm long, rounded at the posterior end, and pointed anteriorly. The sides are parallel,. with only a slight median constriction. Life Cycle. The female deposits large, spherical eggs, sometimes more than 1,000 per season, that hatch in 3 or 4 weeks. The very active larvae attach readily to a host. The ticks become sexually differentiated after the fourth molt, requiring about 4 months, or sometimes not until after the fifth molt. They usually molt once for each feeding (engorgement), but sometimes there are 2 molts between feedings. Effect of a Bite. Herms (1939) described the symptoms of a victim bitten twice by a pajaroello,14 days apart. The first time, the tick was partly engorged, and the second time, it was fully engorged when dislodged. The second bite, on the left leg, was the more severe one. The engorged tick was about 20 mm long and 12 mm wide. A bright-red spot was visible at the point of the tick's attachment, surrounded by an irregular, purple ring about 20 mm in diameter. After 3 hours, the lower leg was greatly swollen, and a clear lymph exuded freely from the lesion. The Genus Argas Species of this genus are important parasites of poultry. Each tick requires a considerable quantity of blood to become replete, and therefore large numbers of them can extract enough blood to cause the death of a bird. Humans have occasionally become infested, generally in or near buildings in which infested fowls were located. In some parts of the world, species of Argas have been implicated as carriers of "avian spirochetosis," a disease attacking chickens, geese, turkeys, guinea fowls, and other birds. The spirochetes are transmitted from one generation of ticks to the next through the egg, thence to the host by the tick's bite or by fecal contamination. Fowl Tick, Argas persicus (Oken) The fowl tick is actually a complex of species including A. persicus. It is cosmopolitan, and is one of the most important poultry parasites. It is also known as "chicken tick," "adobe tick," "tampan," and "blue bug," the latter name referring to the appearance of the female when fully engorged. It will bite humans, and may transmit spirochetes to them (James and Harwood, 1969). HARD TICKS (IXODES) - Hard Ticks Species List - Health Conditions Caused By Ticks - Control of Ticks Description and Biology. The female hard tick has a hard plate or shield on the anterior region of the back (figure 305, B), the remainder of which is smooth, and the body can be greatly extended by feeding. The shield covers the entire back of the male. The mouthparts are visible from above, projecting in front of the body, whereas in the soft ticks they are under the body, and are not visible from above. The pedipalpi (figure 305, B, palpus) are rigid, and are varied in form. The spiracles are situated behind the fourth pair of coxae. The coxae and tarsi are generally armed with spurs, which are absent in soft ticks. Pulvilli are always present in hard ticks, but are absent or rudimentary in soft ticks. The females feed only once, and lay one large batch of eggs often several thousand. Hard ticks are scarce in forests being more abundant in shrubby areas, especially along trails or paths, to which they are attracted by the scents left by animals. Larvae hatching from eggs that have been deposited in some sheltered place will climb to the tips of grass blades or twigs near the trail used by their potential hosts, often clinging together in clusters of 100 or more. Any vibration of their resting place caused by a passing host animal stimulates the larvae to wave their legs about. If the animal brushes against them, they cling to its fur. "One-host ticks" [e.g., the winter tick, Dermacentor albipictus (Packard)] develop to maturity on the host. "Three-host ticks" (e.g., D. andersoni, D. variabilis, and Amblyomma americanum) drop from the host to molt. They may then crawl to a perch near a trail, responding to vibrations as did the larvae, and again cling to the fur of a passing animal. They engorge, and again drop off the host to molt, most species overwintering as unfed adults. Hard ticks cannot stand as much desiccation as soft ticks, and the latter generally survive in much drier situations. These ticks are usually ornate, having pale markings.on the dorsum, and possess eyes and 11 festoons. The palpi are short, and are either broad or moderate, and the basis capituli is rectangular dorsally. The spiracles are suboval or comma-shaped. As bloodsucking parasites and as disease vectors, species of Dermacentor, the wood ticks, constitute the most important group of ticks in the United States. Wood ticks are not only carriers of disease, but the toxins injected with their bites cause itching and a sickness known as pyrexia (a febrile condition). Invertebrates are commonly paralyzed by arthropod venoms, but apparently the only parallel phenomenon in vertebrates is the paralysis caused by the bites of wood ticks. Salivary secretions of the ticks cause a neuromuscular block, presumably at the presynaptic terminal fibers of somatic motor axones, which results in the failure of release of acetylcholine. Recovery is rapid and complete if the ticks. are removed before respiratory paralysis ensues (Beard, 1963). (See the section headed "Tick Paralysis," farther on.) The life history of wood ticks can be illustrated in a general way by that of the American dog tick, Dermacentor variabilis, which was worked out in great detail by Smith et al. (1946). American dog tick, Dermacentor variabilis (Say) This tick occurs on the Pacific Coast and east of the Rocky Mountains. Like its counterpart in the Rocky Mountain area, D. andersoni, it is not only a vector of the causal organisms of Rocky Mountain spotted fever and tularemia, but is also a common cause of tick paralysis. It is commonly found on dogs and, in the eastern United States, it is the species most likely to be found on man. Dermacentor variabilis is seldom found in homes unless carried in while it is feeding on a dog and then drops off to seek a hiding place. It is not a domiciliary species as in the case of the brown dog tick, Rhipicephalus sanguineus, an account of which see farther on. Description of Adults. The adult male (figure 306, C) is about 4.5 mm long and 2.5 mm wide. The dorsal shield is dark brown, marked with a variable pattern of white. The unfed female (figure 306, D) is slightly larger than the male. Her shield, which is restricted to the anterior portion of the dorsum, is much more extensively marked with white than in the male. The male does not become larger as he feeds, but the female enlarges (figure 307) to about 13 mm long by 10 mm wide. The size of the shield does not change, but it becomes inconspicuous in relation to the greatly expanded remainder of the body (Smith et al., 1946). Life Cycle. Over a 14- to 32-day period, the female lays masses of 4,000 to 6,500 ellipsoidal, yellowish-brown eggs, and then dies. The eggs normally hatch in 36 to 57 days. The larvae (figure 306, A) lack spiracles, have only 3 pairs of legs, have red markings near the eyes, and lack white markings on the shield. Unfed larvae are yellow, and about 0.6 mm long; engorged specimens are slate gray to black, and are about 1.2 mm long. The unfed larvae crawl about, seeking hosts, and can live for more than a year (maximum, 540 days) without food. In a simulated meadow, larvae became engorged on mice in an average of 4.4 days, then dropped from their hosts to seek protected places in which to molt. The nymphs lacked a genital opening and the white markings on the shield that characterized the adults. The unfed nymphs (figure 306, B) were light yellowish brown, with red markings near the eyes, and were about 1.5 mm long. The engorged nymphs were slate gray, and about 4 mm long. As with the larvae, they crawled about seeking hosts. The engorging period ranged from 3 to 11 days; the greatest number dropped on the sixth day, and found protected places in which to molt. They molted after 3 weeks to several months. Nymphs also could live for more than a year without food; the maximum period was 584 days (Smith et al., 1946). Unengorged adults may live for more than 2 years if they do not find dogs or other large animals to which they can attach themselves. The engorgement of females requires 5 to 13 days, and mating takes place on the host. In the absence of suitable hosts the life history of the American dog tick may be prolonged to 2 or more years, but under favorable conditions, it may not take more than 3 months. Hosts. In the field in Massachusetts, meadow mice were the most important hosts of the larvae and nymphs, while dogs were the most important for adults. Dogs can pick up hundreds of ticks in a day, and horses and cattle also suffer some annoyance (Smith et al., 1946). Rocky Mountain wood tick, Dermacentor andersoni Stiles This tick (plate VIII, 6) is found in the Rocky Mountain states, as well as in Nevada, eastern Oregon and Washington, and in parts of California east of the Sierra Nevada and Cascade mountains. It is superficially almost identical to D. variabilis. Cattle, horses, and dogs can become seriously infested. Only the adults feed on such large animals and on man; the larvae and nymphs feed on small wild animals, especially rodents. In areas where D. andersoni occurs, it is the principal vector of Rocky Mountain spotted fever, transmitting it from small mammals (principally rodents) to man. Shoshone Indian braves exposed their squaws to the "evil spirits" believed to be associated with gophers in the foothills of the Rockies, and the braves avoided areas shown by this pragmatic test to be inhabited by the evil spirits. When white men brought large, domesticated animals into the foothills, the tick population multiplied closer to fixed settlements, and Rocky Mountain spotted fever became a much greater problem to white men than it originally had been to the Indians. What originally was thought to be a regional nuisance has now been shown to be a world-wide problem, for RMSF has been recognized in North and South America, and similar infections have occurred in Europe, South Africa, India, and Australia (Aikawa, 1966). Biology. Nymphs and adult ticks spend the winter among grass and leaves on the ground, without feeding, and not until the first warm days of spring do they climb up on the brush to become attached to passing hosts. They feed only from about the middle of March to the middle of July, and this is the only period when people contract spotted fever. lone star tick, Amblyomma americanum (L.) The lone star tick, so called because of the silvery spot on its dorsal surface, ranges from west-central Texas to north Missouri and eastward to the Atlantic Coast. Its abundance in some areas, particularly in the Ozark region and eastern Oklahoma, regions characterized by the brushy-type vegetation so conducive to high tick populations, is believed to be a threat to their economic development. In the eastern and southern states, this tick has been a pest since early in the 18th century (Bequaert, 1946), and currently attacks man more frequently than does any other species. Its severe bites are accompanied by extensive inflammation, suppuration, and subsequent development of lesions. Residents and tourists in the Ozark region encounter the pest practically every day during the "tick season" in untreated recreation areas. Hundreds of workers are stricken by any one of several debilitating tickborne diseases, particularly tularemia. Up to 57% of all new-born fawns in certain areas of the Ozark region are lost because of lone star tick infestation. Severe weight losses are suffered by infested cattle. Control with pesticides is made difficult by certain characteristics of the biology of the lone star tick (Hair and Howell, 1970). Biology. In Oklahoma, engorged females seldom appear on hosts before mid-March, and maximum numbers of fed females drop from domestic livestock and deer during late April, May, and early June. After a lapse of 5 to 16 days, the dropped females oviposit under available ground litter, frequently depositing over 5,000 eggs per egg mass. The eggs generally hatch in about 30 days. The larvae climb to the tops of plants. Heavy rains and strong winds tend to dislodge them, and over 90% apparently perish under such circumstances. Lone star ticks overwinter in the fed larval stage, unfed nymphal stage, and 2 forms of adults: unfed adults, or fed nymphs that become adults during the winter after exposure to adequate warmth. The ticks normally contact their hosts when the latter brush up against them on the tips of tall grasses and shrubs. However, if the host remains in the area for a considerable time without contacting them, nymph and adult ticks may become stimulated by heat and carbon dioxide from the host's body, and will then fall to the ground, find the host, and climb onto it. Larvae depend almost entirely on the host to make contact with the larval mass as it hangs from the tips of vegetation; they seldom seek a host (Hair and Howell, 1970). The bite of the wood tick is not felt immediately, even though the tick remains attached, but the bite causes more or less inflammation later. If the tick is not removed with care (see "Removal of Ticks," farther on), its mouthparts usually remain in the skin and cause an ulcer that can become, infected. Another possible consequence of the bite, if a gravid female tick attaches at the back of the neck or base of the skull and feeds there for a week or so, is a disease known as tick paralysis. A paralysis develops, and if the tick is not removed, death by respiratory failure may result. Human beings, particularly children, have been affected, but more frequently domestic range animals are the victims. In North America, tick paralysis has been most common in the Pacific Northwest, where it had been known since the first decade of this century, and by 1954, 332 human cases had already been recorded. Dermacentor andersoni was almost always the tick that was implicated. The mortality rate was 11.7%, despite the fact that there is usually a latent period of about 5 days before D. andersoni can produce enough toxin to cause paralysis, and paralysis can be avoided by removal of the ticks during that period. For some 12 to 24 hours before the onset of actual paralysis, there may be vague complaints, irritability, tiredness, and pain or paresthesia (sensation of prickling, tingling, or creeping on the skin), in the lower extremities. There then occurs a loss of coordination, followed in a few hours by flaccid paralysis in the lower extremities. In another 12 to 24 hours, the paralysis ascends to the arms if the ticks are not removed. If the ticks are removed, recovery is rapid (Rose, 1954). Not all female ticks can cause paralysis, and the reason for this is not known. Tick strains in some areas are more dangerous than in others. Using hamsters as experimental animals, Hughes and Philip (1958) found that ticks (D. andersoni) from British Columbia caused a much higher rate of paralysis than ticks from the Bitter Root Valley of Montana. This may account for the statistics presented by Rose (1954), showing about 72% of the cases of tick paralysis in the Pacific Northwest to be from British Columbia. In California, D. andersoni occurs in the northeastern part of the state and southward along the eastern slope of the Sierra Nevada to Mono County. Instances of tick paralysis in deer and cattle, but not humans, are known from California. All clinically observed human cases have been acquired in Oregon or elsewhere (R. F. Peters, correspondence). However, the potential for tick paralysis, as well as the tick fevers (described following) would appear to exist. Vacationers in tick-infested areas should examine themselves daily to make certain that a tick has not embedded itself anywhere on the body. In the eastern and southern states, tick paralysis was not reported until 1938 (Costa, 1952). The species of ticks implicated have been Dermacentor variabilis, Amblyomma americanum, and A. maculatum Koch. T'he "Colorado type" of tick fever is caused by a virus, and is known to occur in western Canada and in Washington, Oregon, Idaho, Montana, California, Nevada, Utah, Wyoming, Colorado, and South Dakota. It is described as "an acute, febrile, dengue-like disease, usually without rash; a brief remission is usual, followed by a second bout of fever, each lasting 2 or 3 days. Characteristically mild, but may be severe in children, occasionally with encephalitis or tendency to bleed; deaths are rare." The reservoirs for the virus of Colorado tick fever are many species of ground squirrels, chipmunks, mice, wood rats, and other rodents. Ticks also serve as long-term reservoirs (CPHS, 1971). The distribution of Colorado tick fever in California has coincided with that of its usual vector, Dermacentor andersoni. In 1957-1970, there were 115 laboratory-confirmed cases of Colorado tick fever in California, the majority acquired in that state but some in endemic areas from other states (CPHS, 1971). Since 2 tick fevers - Colorado tick fever and Rocky Mountain spotted fever - occur in California and other western states, the 2 diseases should be differentiated, and each should be given its full name in scientific papers and news releases. Rocky Mountain spotted fever (RMSF) is endemic throughout the United States outside of New England, particularly in mountainous regions, as well as in Canada and some parts of Mexico and South America. RMSF, first known in the Bitter Root Valley of Montana as early as 1872, is no longer a regional curiosity, and Aikawa (1966) suggested that it be called "rickettsial spotted fever," honoring the name of H. T. Ricketts, the most active and effective early investigator of the disease. In the West, the Rocky Mountain wood tick, Dermacentor andersoni, is the principal vector, both male and female ticks being infective; and in the East, the American dog tick, D. variabilis, is the most important vector (Larson, 1955). The rabbit tick, Haemaphysalis leporispalustris (Packard), is also a vector in the West, and the Pacific Coast tick, D. occidentalis Marx, is suspected, The lone star tick, Amblyomma americanum, is considered to be a probable vector in parts of the eastern United States, and in Texas, Oklahoma, and Arkansas (Pratt and Littig, 1962). It appears that any tick that infests the approximately 40 hosts of rickettsia is a potential vector. Birds are believed to be important factors in dissemination of ticks that harbor rickettsial agents, including Rickettsia rickettsia, the RMSF pathogen (Clifford et al., 1969). Rickettsias are a group of microorganisms about the size of small bacteria, and on the biologic scale they lie between the viruses and the bacteria. Besides the various spotted fevers, they are the causal organisms for the typhus fever group of rickettsial diseases, scrub typhus, fever, and probably trench fever. Symptoms. RMSF is a severe, acute, infectious disease of the small peripheral blood vessels. It is said to cause greater damage to tissues on the surface of the body and to those of the brain than does any other rickettsial disease. Mortality to humans is commonly 20% or more (Rivers and Horsfall, 1959; Aikawa, 1966). A rash appears about the second to fifth day after a bite, on the wrists, ankles, and less often on the back, later spreading to all parts of the body. This rash is the most characteristic symptom of RMSF. The rash is sometimes preceded by a mottled appearance of the skin. The spots may become necrotic on the extremities. At the outset, the patient complains of frontal and occipital headache, intense aching in the lumbar region, and marked malaise. The incubation period may be 3 to 12 days in the milder infections and 2 to 5 days in the more severe ones. Before the initial chill, only minimal evening fever is experienced, but after the chill, the temperature continues to rise, reaching 102 to 104 °F (39 to 40 °C) on the second day, and then rises gradually to a maximum of 104 to 105 °F (40 to 40.6 °C) in the second week. In the virulent cases in the Bitter Root Valley of Montana, the temperature may reach 106 to 107 °F (41 to 41.6 °C), and may remain this high until the patient dies. The pulse rate may reach 150 and the respiratory rate 60 per minute in the terminal phase of the disease (Aikawa, 1966). Transmission. Ticks transmit Rickettsia rickettsii from any small mammal to man during frost-free periods of the year. The organism enters the gut of a tick with the blood it sucks from its host and then spreads to all parts of the body, including the salivary glands. Fortunately, the disease is not transmitted unless the tick remains attached to its host for 2 hours or more. The disease is passed from one generation of ticks to the next via the egg, without decrease in virulence (Price, 1953). Despite transovarial transmission of R. rickettsia, the tick apparently suffers no ill effect, and the vertebrate vectors also appear to be in symbiotic relationship with the tick and suffer no evident clinical disease (Aikawa, 1966). Vaccination. A high degree of protection to people who are frequently exposed to tick bites is afforded by vaccination - initially 3 injections at 5- to 7-day intervals and each year thereafter a booster shot. As a result, the number of reported cases of RMSF is steadily decreasing (Pratt and Littig, 1962; Aikawa, 1966). Another rickettsial disease sometimes transmitted to man by ticks is Q fever (query fever), also known as coxiellosis or nine-mile fever, the causal organism for which is Coxiella burnetii. It has been reported from all continents, and in the United States, outbreaks have occurred most commonly among stockyard workers. Transmission to man is usually by inhalation of dust. Milk can be a source of infection. Tick species that have been found infected are Dermacentor andersoni, Amblyomma americanum, Otobius megnini, and many others (Horsfall, 1962; Pratt and Littig, 1962). Vaccination of persons liable to be exposed to infection has been effective (Hunter et al., 1960). This is a disease caused by the bacillus Francisella tularensis, that occurs in the continental United States, Alaska, Canada, northern Europe, Japan, and many other parts of the world. In the United States, it was first reported in Utah in 1919 and was called "deer fly fever," but was later reported among various rodents in Tulare County, California. Rabbits are important reservoirs for this bacillus, and it is mechanically transmitted from rabbit to rabbit by the deer fly Chrysops discalis (Francis and Mayne, 1921). However, ticks may be more important than deer flies in the transmission of this disease (James and Harwood, 1969). In fact, at least 54 species of arthropods can harbor the tularemia bacillus (Steinhaus, 1946). Besides existing in rabbits, tularemia is also known to be carried by meadow mice, ground squirrels, beavers, coyotes, sheep, and various game birds. When transmitted to humans by deer flies, exposed body surfaces are bitten, and the on set of pain and fever is sudden. Lymph glands become inflamed and swollen. The fever lasts for 3 to 6 weeks, and the patient generally convalesces slowly (Francis, 1919). Louseborne relapsing fever and tickborne relapsing fever are both caused by spirochetes of the genus Borrelia, and they cannot be distinguished with certainty on the basis of clinical manifestations. (See comment in the earlier section on lice.) Most authorities believe that the spirochetes transmitted by lice and ticks are variants of the species Borrelia recurrentis, but many "species" have been identified by geographic location and by their argasid tick vectors, and were listed by Dubos and Hirsch (1965). It is reasonable to suppose that the isolation resulting from the burrow- or den-infecting habits of argasid ticks may have led to the development of different strains of a single pathogen. Tickborne relapsing fever tends to be endemic, and is completely so in the United States. In California, relapsing fever is most commonly contracted from the bites of argasid ticks, generally Ornithodoros hermsi, and usually at elevations ranging from 5,000 to 8,000 ft (1,500 to, 2,400 m). Ticks in rodent-infested mountain cottages are common sources of the spirochetes (Herms and Wheeler, 1936). Infected ticks (O. hermsi, O. turicata, O. parkeri, and O. talaje) have been found in California, Arizona, New Mexico, Utah, Idaho, Montana, Colorado, Kansas, Oklahoma, Texas, and Florida. In Texas alone, 100 cases of tickborne relapsing fever were diagnosed from June, 1942, to May, 1949 (Dubos and Hirsch, 1965), and in California, there were 65 recorded cases from 1950 through 1970 (CPHS, 1971). In both states, many additional cases probably escaped detection. Species of Ixodes Members of the genus Ixodes can be readily distinguished from all other hard ticks (Ixodidae) by the groove surrounding the anus in front, and by the absence of "festoons," which are illustrated in figure 305, B. In California, the Pacific tick, Ixodes pacificus Cooley and Kohls, is common on deer and cattle and bites humans freely, commonly causing marked systemic disturbances. This species is related to the European castor bean tick, Ixodes ricinus (L.), and in fact was formerly considered to be a variety of that species. The castor bean tick is so designated because of its color, shape, and the enormous size of the engorged female, up to 14 mm in length. Particularly serious consequences result from removing the tick when the capitulum is allowed to remain embedded in the skin. This may lead to irritation and infection. The sensory physiology and behavior of I. ricinus were investigated in great detail by Lees (1948). The data are worth recording because they may hold for ticks in general. While crawling, the unfed female waves its first pair of legs like antennae. It uses these legs for crawling when it is not hungry. On the tarsi of its legs is Haller's organ, which contains sensilla stimulated by odor and humidity. As already stated, ixodid ticks climb to the tops of grass blades and twigs and wave their forelegs about when stimulated to do so by an approaching animal, and will cling to the passing host. The tips of the pedipalps of I. ricinus have sensory pads used for selection of a suitable feeding site on the host. Ixodes ricinus spends most of its life in microclimates of very high humidity, so desiccation forces the tick to periodically move down to the moist base of the herbage upon which it has climbed so that it can absorb moisture through its cuticle. One is reminded of similar periodic trips of subterranean termites, via their shelter tubes, from dry structural timbers to moist subterranean galleries where they can replenish their body moisture by cuticular absorption. brown dog tick, Rhipicephalus sanguineus (Latreille) The brown dog tick differs from members of the preceding genus in that it rarely attacks man, yet is the species the homeowner is most likely to be obliged to deal with, for it is a common pest of dogs. Description of Adults. The male is about 3 mm long, flat, uniformly reddish brown, and has tiny pits scattered over the back. The female (figure 308) before feeding resembles the male in size, shape, and color. When engorged with blood, she can reach about 12 mm in length. The engorged part of the body then changes in color to grayblue or olive. Life Cycle. The engorged female falls off the dog, and seeks a sheltered place in which to lay a mass of 1,000 to 3,000 tiny, dark-brown eggs. These may be deposited in any available place, but because she tends to crawl upward, they are likely to be deposited in cracks or crevices in the roofs of kennels or the ceilings of porches. The female then dies, and her eggs hatch in 19 to 60 days. Cool and/or dry weather tends to prolong the hatching period. The minute, 6-legged, lightbrown larvae or "seed ticks" move to the lower parts of walls, and attach themselves to a dog at the first opportunity, but can survive as long as 8 months without food or water. After finding a host, they engorge themselves in 3 to 6 days changing from flattened to globular in shape: about 2 mm in diameter, and become bluish in color. They then drop, hide in cracks to molt, and in 6 to 23 days become 8-legged, reddish-brown nymphs. After a few days of inactivity, the nymphs are ready to attach themselves to a dog, but like the larvae, they can live for months without food or water. Once attached, they engorge in 4 to 9 days and become oval, about 3 mm wide, and dark gray. They then drop off the dog, hide, and molt in 12 to 29 days. They are then adults, for among the hard ticks there is only a single nymphal instar. The adults will attach themselves to a dog at the first opportunity, but they can live as long as 18 months before attachment. They then engorge themselves with blood in 6 to 50 days, mate, and the females drop off to oviposit and repeat the life cycle (Bishopp, 1939). Under favorable conditions, the life cycle may be completed in 63 days at 85 °F (29 °C). However, under the usual environmental conditions and delays in attachment to the host, there are seldom more than 2 generations per year in the North and 4 in the South. The brown dog tick prefers warm, dry situations, and seldom develops in large numbers outdoors in the United States. Obnoxious Features. Besides infesting dogs, the brown dog tick can be a serious nuisance in the home, where it may be seen emerging from numerous hiding places. Even if ticks are eliminated from a dog and its kennel, as well as from the home, it can pick up ticks from other infested residences in the neighborhood, from a boarding kennel, or when taken along on a vacation. A dog can pick up ticks that have dropped from another dog, but cannot become infested by direct contact, because a feeding tick drops off and molts before attaching itself to a new host. Ticks may attach themselves anywhere on a dog, but are most often found on the ears and neck and between the toes. Larvae and nymphs are often found in the long hair on the back. By sucking large quantities of blood, ticks can reduce a dog's vitality and cause it to be irritable. They transmit a canine disease known as piroplasmosis in various parts of the world. The causal organism is a protozoan, Babesia canis, that infects red blood cells, but the disease is rare in the United States. One obvious means of tick control is to avoid becoming infested. Some degree of protection can be obtained by keeping clothing buttoned and tucking trouser legs into the tops of socks or boots. One should also avoid sitting on the ground or on logs in brushy areas. Periodic inspection of the clothing and body and removal of ticks before they become attached should be done in order to avoid exposure to tick paralysis and various other tickborne diseases. If ticks do become attached, it is important to know the best way to remove them. Removal of Ticks Attached to the Body. It is desirable to remove attached ticks without leaving the capitulum embedded in the skin. Pratt and Littig (1962) recommended as follows: If ticks become attached, the simplest method of removing them is by a slow, steady pull that will not break off the mouthparts and leave them in the wound. There is no certain way to make a tick detach its mouthparts. A drop of chloroform, carbon tetrachloride, ether, benzene, vaseline, or fingernail polish rubbed over it will help remove the tick. Several minutes to a half-hour later, when the tick has withdrawn its mouthparts, it can be removed with less damage to the skin. Touching the tick with the lighted end of a cigarette (or a hot needle) sometimes causes it to release attachment. An antiseptic should always be applied to tick bites just as to open wounds. If the hands have touched the tick during removal, wash them thoroughly with soap and water, since the tick secretions may be infective. For the removal of Ixodes ticks, Busvine (1966) suggested that, after dabbing them with chloroform or ether, the capitulum should be pressed inward to loosen the "teeth," and then the tick should be gently pulled away. Some ticks, such as Amblyomma and Ixodes, have longer mouthparts than others, such as Dermacentor. Their mouthparts penetrate more deeply, even through socks, and the ticks are harder to remove. All types of repellents may be rendered relatively ineffectual by the tendency of ticks to crawl underneath clothing and attach themselves to untreated portions of the body. Therefore, treatment of clothing is recommended. Good protection is afforded by M-1960, Indalone, diethyl toluamide, dimethyl carbate, dimethyl phthalate, or benzyl benzoate (Pratt and Littig, 1962). In areas having frequent visitors, such as city parks, it should be borne in mind that ticks do not travel far after having a blood meal and dropping off their hosts. Therefore, the greatest numbers are found along walks and the edges of lawns. Adequate economical control might be obtained by applying pesticides in swaths 10 to 20 ft (3 to 6 m) wide along paths, roadsides, and the edges of lawns and gardens, where most of the ticks occur and where most exposure of humans is likely (Pratt, 1962; Pratt and Littig, 1962). Control of ticks in areas having heavy plant growth can be obtained with dust, suspension, or emulsion formulations of various recommended residual pesticides, applied by hand or power equipment, or in certain situations by aircraft. Sprays are generally applied to grassy and brushy areas adjacent to human and domestic animal habitations, along roadsides and footpaths, vegetation surrounding camping and picnic sites, or wherever ticks may be present and annoying. Contamination of feed or foodstuffs, fishbearing water, or blossoms visited by bees should be avoided. A spray consisting of Gardona 75 wettable powder at a concentration of 0.5% of actual toxicant has been recommended for tick control when an insecticide of low mammalian toxicity and without long-lasting residues is desired, such as in recreation areas. The spraying can begin in the early spring when ticks first appear, and can be repeated if necessary. In recreation areas, the first spraying should be done shortly before the early summer influx of visitors (Hair and Howell, 1970). Park Maintenance. In parks and other recreation areas, grass should be mowed periodically, for grass over 6 in. (15 cm) high offers considerable protection for ticks against the sun and dryness. Also, mowing will dislodge and disperse masses of "seed ticks," after which most of them succumb to desiccation. Tall grass also has the disadvantage of providing cover for host animals. An excessive "overstory" of trees and shrubs should be avoided in heavily infested areas, so that from 50 to 80% of the ground in a park is exposed when the sun is in any one position. The brown dog tick is the species the homeowner is most likely to have to deal with, although the American dog tick and other species also enter the home on pets. The present recommendations pertain to the brown dog tick, which accounts for the emphasis on organophosphorus pesticides. It is necessary to use pesticides of long residual efficacy, because tick eggs may be protected from the spray in cracks or behind baseboards and moldings. Even if they are hit by the pesticide, they are not always killed, so the residue left by it must be able to kill the larvae hatching from the eggs after they start crawling about. Resistance to chlorinated hydrocarbons is now widespread in the United States, and they are no longer generally recommended. Oil solutions or water emulsions of 1% propoxur, 0.5% diazinon, 0.5% dioxathion, 0.5% chlorpyrifos, 1.5% fenthion, 1 or 2% malathion, 2% ronnel, or a dust containing 5% carbaryl have been suggested (CDC, 1973). Except for malathion and ronnel, when these pesticides are used indoors they should be applied only as "spot treatments" to the usual harborage sites. Sometimes ticks are present in subfloor crawl spaces, under porches, and in other areas accessible to the dog but difficult to treat with a spray. Dust formulations containing the pesticides just mentioned can then be used most effectively. When treating for the brown dog tick, the objective should be to, apply the spray or dust to areas frequented by the dog, paying special attention to its sleeping quarters, as well as to baseboards, doorways, window casings, floor and wall crevices, and beneath the edges of carpets. If the dog is permitted on overstuffed chairs, the cushions should be removed and all crevices and seams treated. In warmer climates, if the dog spends much time outside, the yard also should be treated, along with the doghouse, subfloor crawl spaces, and other areas accessible to it. Retreatment may be necessary 1 or 2 weeks later for severe infestations. When the premises are treated, the dog must also be treated, or reinfestation will occur. The owner may do this himself, or have it done by a veterinarian. Recommended treatments are washes of 1 % coumaphos or 0.5% malathion, or dusts of 5%, carbaryl, 0.5% coumaphos, 1% trichlorfon, or 3 to 5% malathion. Better penetration of the dog's fur may be obtained with liquid washes. The coumaphos wash or trichlorfon dust should not be used on dogs under 2 months of age. Veterinarians may use animal dips containing 0.1% dichlorvos, 0.2% naled, 1% carbaryl, 0.15% dioxathion, or 1%, ronnel. Veterinarians have also reported success with the oral use of ronnel (CDC, 1973). - Mites Species List - Chiggers (Trombiculidae) - straw itch mite, Pyemotes ventricosus (Newport) (Pyemotidae) - tropical rat mite, Ornithonyssus bacoti (Hirst) (Macronyssidae) - house mouse mite, Liponyssoides sanguineus (Hirst) (= Allodermanyssus) (Macronyssidae) - northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago) (Macronyssidae) - chicken mite, Dermanyssus gallinae (De Geer) (Dermanyssidae) - human itch mite, Sarcoptes scabiei var. hominis (Hering) (Sarcoptidae) - canine mange mite, Sarcoptes scabiei var. canis Gerlach, on Dogs and Humans Mites (order Acarina) are very small arthropods, with head and thorax fused into a cephalothorax. They have sucking mouthparts, no antennae, and those of interest as household pests have 4 pairs of legs as adults. Although most of these species have only 3 pairs of legs in the first (larval) stage after hatching from the egg, they gain a fourth pair in the second (nymphal) stage. The life cycle generally consists of the egg, larval stage, one or more nymphal instars or stages, and an adult stage. The life cycle usually requires only 2 or 3 weeks, and results in rapid increase and huge populations of mites under favorable conditions. A thorough discussion on the morphology and development of the free-living mites, on their role as parasites of animals and plants, and as vectors of disease, may be found in Mites, or the Acari by T. E. Hughes (1959). Chiggers or "red bugs," called "harvest mites" in Europe, are.the larvae of mites belonging to the suborder Trombidiformes, which are worldwide in distribution. There are over 200 families of mites, but the family to which chiggers belong (Trombiculidae) contains about 10% of all mite species (Sasa, 1961). Some species attack humans and cause a dermatitis (trombidiosis). The red welts and severe itching do not appear until several hours or even a day after exposure; therefore, it is difficult to know exactly when or where the infestation occurred. Several chiggers transmit a rickettsial disease called "scrub typhus" or "tsutsugamushi disease" in the Orient and various areas of the Pacific. Description. The members of the suborder Trombidiformes are characterized by the respiratory system, when present, opening in the region of the gnathosoma, the portion of the body bearing the mouth and its appendages. Chiggers are very small, 150 to 300 microns (0.15 to 0.3 mm) long when unengorged, and are red to pale yellow or white, depending on the species. Like all mite larvae, they have 6 legs. They are parasitic, but later stages are free-living, 8-legged mites. Only the larvae are harmful and only they are correctly referred to as "chiggers." The adults are bright red, hairy, or granular (Michener, 1946; Wharton and Fuller, 1952; Baker et al., 1956). The various stages of the trombiculid mites in general are adequately represented by figure 309, which shows an unengorged and engorged larva, a nymph, and an adult of Trombicula batatas (L.). common chigger, Trombicula alfreddugesi (Oudemans) In the Western Hemisphere, this is the most common and widespread species, ranging from Canada to South America and the West Indies. Trombicula alfreddugesi parasitizes many species of mammals, birds, reptiles, and amphibians, as well as man. On humans, chiggers tend to congregate in areas constricted by clothing, such as ankles, crotch, waistline, and armpits. It is unfortunate that when chiggers attach to humans they are not noticed for some time, for they are easily removed. According to Baker et al. (1956): Itching is usually noted 3 to 6 hours after the chiggers have attached, and may persist for as long as 2 weeks. Part of the irritation is thought to be an allergic response to the salivary secretions of the mite. A papule forms at the site of attachment which may develop into a vesicle. Scratching usually removes the offending mite but, if repeated often enough, may result in an infection. In some regions, this mite is a.pest of chickens and turkeys, affecting the younger birds most seriously. When heavily parasitized, the birds become droopy, refuse to feed, and may eventually die from starvation and exhaustion (Baker et al., 1956). A much more important chigger pest of chickens and turkeys, however, is Neoschongastia americana (Hirst), which ranges across the southern United States from California to Georgia, but does not attack man (Kunz et al., 1969). Description. Chigger larvae are 0.15 to 0.25 mm long before engorgement, and are red to reddish orange, rarely white. Their mouthparts include 2 pairs of grasping palps provided with forked claws. The nymphs are much more hirsute than the larvae. The body is constricted behind the second pair of legs, giving them and the adults the characteristic shape of trombiculid mites shown in figure 309. The adults are much larger than the nymphs, and are even more hirsute. They are 0.9 to 1.1 mm long, and brilliant red (Jenkins, 1949; Baker et al., 1956). Life Cycle. The spherical eggs, approximately 0.1 to 0.2 mm in diameter, are usually laid in the soil. The larva crawls about on the surface of the soil until it finds a suitable vertebrate host. It attaches to the host by means of its chelicerae and sucks blood, but as a rule does not burrow under the skin. Engorgement usually takes about 3 days. The larva then drops, enters the soil, and changes, via the nymphochrysalis, to the nymphal stage. The nymphs probably feed on the eggs and young instars of small arthropods. The adult emerges from a dorsal split in the imagochrysalis and nymphal cuticle (Baker et al., 1956). The life cycle may require 2 to 12 months or longer, depending on the temperature. There may be 1 to 3 generations per year in temperate climatic zones, but reproduction may be continuous throughout the year in warmer regions, with as many as 6 generations. Females kept at suitable temperatures and supplied with water and food were observed to live more than a year and to produce larvae throughout that period. The time when chiggers are active varies from 2 months in Minnesota and Massachusetts to the entire year in southern Florida. Chiggers are most abundant during rainy spells in the area from Kansas to Texas, and may disappear during hot, dry weather (Jenkins, 1948). Trombicula splendens Ewing is a related species in the eastern United States. It prefers moister habitats, such as swamps and rotten logs or stumps. It is one of the most common causes of trombidiosis in the southeastern states. Trombicula lipovskyana (Wolfenbarger) may be found in similar places in Tennessee, Kansas, Oklahoma, and Arkansas. Trombicula belkini Gould is widely distributed in California, and has also been collected in Utah. Reptiles seem to be its favored hosts, but it also infests rodents and ground birds. It sometimes annoys humans and their pets (CEIR, 1960). This species is closely related to T. alfreddugesi, but the larvae lack nude, whiplike setae on the tarsus of leg II (Baker et al., 1956; Gould, 1956). Trombicula batatas (L.) (figure 309) is common in Central and South America, the state of Puebla, Mexico, and has been reported from the southeastern United States (Michener, 1946; Jenkins, 1948). It has been collected on humans and many domestic and wild animals. One 12-year-old boy had 138 attached larvae (Michener, 1946). It has been reported to attack humans in the San Joaquin Valley of California (Doetschman and Furman, 1949). Gould (1956) published an extensive monographic study of the larval trombiculid mites of California. Favored Habitats. Chiggers are most abundant in areas that support thickets or scrub-type vegetation and where the ground is undisturbed, supporting many rabbits, other rodents, and various small host animals. They are generally eliminated automatically by habitat destruction in areas that are heavily populated or intensively farmed. In new urban subdivisions, however, chiggers may persist in lawns for several years. To determine the exact area of chigger infestation, a piece of black cardboard can be placed edgewise on the ground where an infestation is suspected. If chiggers are present, the tiny yellow or pink larvae will crawl rapidly over the cardboard and accumulate on the upper edge. Chiggers can also be easily detected on black, polished shoes (USDA, 1963). Jenkins (1948) suggested the possibility that chiggers might be of value in decreasing mosquito populations. The adults were often abundant in depressions in the ground which had become temporary pools containing Aedes and Psorophora larvae in the spring. Mosquito eggs laid in such depressions probably were serving as food for Trombicula adults. Repellents. In areas where chiggers are known to be a problem, the avoidance of their favored habitats is, of course, a way of minimizing infestation. Protective clothing and repellents are recommended as already described for protection against mosquitoes and ticks. If infested, a thorough soapy bath as soon as possible is a highly effective treatment. Repeat the lathering and rinsing several times. Most of the chiggers, attached or unattached, will be killed. Among the best repellents for chiggers are those containing diethyl toluamide (OFF), ethyl hexanediol (6-12), and dimethyl phthalate, applied to the skin and clothing around the ankles, waist, and armpits. To apply dusting sulfur to skin and clothing is an old but effective method of preventing chiggers. Repellents should be applied particularly to the legs, ankles, cuffs, waist, and sleeves. Some relief from itching can be obtained by applying a solution of 5% benzocaine, 2% methyl salicylate, 0.5% salicylic acid, 73% ethyl alcohol, and 19.5% water. This can be prepared by a druggist. It may be applied to each welt with a piece of cotton. Each treatment gives relief for an hour or more (USDA, 1963). Control. Good control of chiggers in the field can be obtained for 1 or 2 months with toxaphene at 2 lb (0.91 kg) or lindane at 0.25 lb (0.11 kg) of actual toxicant per acre, preferably as emulsions. The amount of water used as a carrier of such quantities depends, of course, on the type of spray equipment available. A given quantity of insecticide can be used with either a large or small quantity of water, as long as the toxicant is thoroughly and uniformly distributed. The following quantities (stated as emulsifiable concentrates) of 4 insecticides that are effective against chiggers as well as insects have been recommended (Anonymous, 1970d). \|Insecticide and formulation\|\|For 1,000 sq ft (93 sq m)\|\|For 1 acre (0.405 ha)\| \|Chlordane 45%\|\|10 tsp (50 cc)\|\|3 pt (1,440 cc)\| \|Toxaphene 60%\|\|7 tsp (35 cc)\|\|2 pt (960 cc)\| \|Diazinon 25%\|\|0.5 pt (240 cc)\|\|2.50 gal (9.50 1)\| \|Malathion 57%\|\|0.5 pt (240 cc)\|\|2.50 gal (9.50 1)\| A convenient way to treat 1,000 sq ft (93 sq m) of lawn would be to mix any one of the formulations shown in the table with 3 gal (11 L) of water, but if weeds or tall grass were present, the same quantities of insecticide could be more effectively applied in 6 gal (22 L) of water. To spray an acre (0.405 ha), at least 25 gal (95 L) of water are required. Malathion treatments may need to be repeated because malathion is nonpersistent. There are also dust formulations of these insecticides that can be used effectively for chigger control. (Consult appropriate authorities about pesticides currently authorized.) straw itch mite, Pyemotes ventricosus (Newport) (Pyemotidae) This extremely small mite, almost invisible to the unaided eye, is primarily a parasite of certain insects, including 3 moths, 10 beetles, 4 wasps and bees, a bug, a fly, and a termite. Some of these host insects infest straw, wheat, stored food products, straw mattresses, and wood, and are therefore found in the home. The straw itch mite has also been called "grain itch," "hay itch," and "straw mattress" mite. Humans can become infested, with resulting dermatitis, by coming in contact with materials such as straw, hay, grasses, grains, and even beans, peas, cottonseed, tobacco, and broomcorn that have been infested with insect larvae upon which the mites feed. These mites also attack horses, cattle, and possibly other mammals (Goldberger and Schamberg, 1909; Baker et al., 1956; A. M. Hughes, 1961; Fine and Scott, 1963, 1965; Scott and Fine, 1963, 1964, 1967; Butler, 1972). Description. The female is an almost microscopically small,. elongate mite (figure 310), 0.22 mm long and white to yellow in color. When gravid, she becomes greatly distended behind the fourth pair of legs, and attains a length of up to 2 mm. Her abdomen shows traces of lateral segmentation, and she has clublike hair between the first and second pairs of legs. The male is only 0.16 mm long, but is wider than the female. Life Cycle. This mite has a strange and unusual biology. The males wander continuously over the distended body of the pregnant female, feeding on it parasitically. The large eggs hatch, and 206 to 300 mites develop to adulthood within the female's enlarged abdomen. They are extruded at the rate of about 50 per day. Only some 3% are males, but they emerge first and remain clustered around the genital opening. With the aid of their hind legs, they drag the females through the opening, even though they can emerge unassisted, and copulation takes place immediately. The females then search for hosts. Only 6 to 10 days are required from the time of fertilization to the hatching of eggs. The mites are active during the warmer months of the year at 80 °F (27 °C) or above (Baker et al., 1956; Scott and Fine, 1963). Distribution of Bites. The bites of straw itch mites are characteristically distributed almost exclusively on clothed portions of the body, although they occur rarely on other areas, with the exceptions of the palms, soles, and mucous membranes. There is no tendency for the mites to be grouped, although this sometimes occurs fortuitously. A person may feel a prickling sensation at the time of the bite, but otherwise no immediate reaction seems to occur. The period between the time of the bite and the delayed reaction has been variously reported as 10 to 16, 16, 27, and 17 to 28 hours (Fine and Scott, 1965). Straw Itch Mite Dermatitis. A considerable number of epidemics of dermatitis have been traced to infestation by Pyemotes ventricosus. Since many such outbreaks have not been recorded or correctly diagnosed, it is likely that this ailment is more common than is generally realized. Straw itch mite dermatitis is usually associated with sleeping on straw mattresses, harvesting grain, or otherwise handling or coming in contact with grain, straw, hay or other substances such as those just mentioned. The possibility of infestation is particularly strong if there are large numbers of the mites' host insects present, such as the Angoumois grain moth (Sitotroga cerealella) and the wheat jointworm (Harmolita tritici). The host insect need not necessarily be a species associated with hay or grain. For example, cases of straw itch mite dermatitis have been associated with severe infestations of furniture beetles (Anobium punctatum) in the floor joists of houses. The recurrence of such cases during the same season for 3 successive years led investigators to conclude that the mites migrated in search of new hosts as the adult beetles emerged and left the wood. The mites apparently were not able to penetrate the thick exoskeletons of the beetles when the latter were in the pupal and adult stages, and therefore they left and sought new hosts. In one house, the mites were controlled by treating the floors with 2% deodorized malathion emulsion (Fine and Scott, 1963, 1965; Scott and Fine, 1963). Treatment and Prevention. The treatment of symptoms is not the solution to the problem. Either a person must avoid infested areas, or the mites and their host insects must be eliminated. tropical rat mite, Ornithonyssus bacoti (Hirst) (Macronyssidae) The tropical rat mite commonly occurs on rats throughout the world, particularly in tropical and subtropical regions, but also in some temperate areas. It is an ectoparasite of rats, and attacks people living in rat-infested buildings. Its bite may cause irritation and sometimes painful dermatitis. It is an important pest of laboratory animals, particularly rats, mice, and hamsters, sometimes deteriorating their health or even causing death by exsanguination (Baker et al., 1956). When rats occur in a house, their fecal pellets may be found in the attic, and can often be seen from the crawl hole. When rats are killed, the mites leave their bodies and may travel great distances, particularly along the heating pipes in the walls, for when they are not engorged with blood they are very active. When searching for mite infestations, a flashlight should be used and warm areas such as those near hot-water and steam pipes should be examined with particular care. Description. The tropical rat mite is gray to pale yellowish gray, changing to red or black when engorged with blood (figure 311, inset). The females vary in length from about 1.15 mm when unfed to 1.41 mm when engorged. The males are about two-thirds as long as the females. A useful taxonomic character is the single dorsal plate, which is relatively narrow and does not cover the entire dorsal surface, even in specimens that have not fed. The dorsal plate bears pairs of long setae, more numerous on the anterior half and in most specimens with only 6 or 7 pairs on the posterior half (Skaliy and Hayes, 1949; Baker et al., 1956). Life Cycle. After the adult female engorges, her first eggs may be laid within 2 days at ordinary temperatures (68 to 72 °F; 20 to 22 °C). They are deposited on debris in rat nests and burrows, but apparently not on the rats themselves. They hatch in about 36 hours. The larvae do not feed, and within a day they molt to enter the first nymphal stage, the protonymph. The protonymphs attach to a host and obtain a blood meal before dropping off and molting to become deutonymphs. In this stage they do not feed, but in 24 to 36 hours molt to become adult males or females. They mate and engorge within 3 days. Unfertilized females reproduce parthenogenetically. Four or 5 blood meals are required for the completion of the entire life cycle. The life of an adult female was found to average 61.9 days; the number of eggs laid, 98.8; and the life cycle from egg to egg, 10 to 12 days (Sheimire and Dove, 1931; Bertram et al., 1946; Baker et al., 1956). Tropical Rat Mite Dermatitis. When the mites are abundant, they may be found anywhere in the house, and both nymphs and adults may attack people. Their bites produce irritation, and sometimes a painful dermatitis will continue for 2 or 3 days, leaving red spots on the infested areas (figure 311). Scratching may result in secondary infections. Within some households certain individuals are affected while others are not. Sometimes, much time and money will be spent on ineffective medication and it is usually difficult for the infested person to obtain a correct diagnosis. This acariasis cannot be distinguished from flea bites, and is sometimes misidentified as scabies. Control. The complete control of rats would, of course, eventually result in the elimination of tropical rat mites from infested premises. However, rat control often proves to be difficult, and "ratproofing" an attic may also be difficult and very expensive. It should also be borne in mind that trapping or otherwise killing rats may increase the attacks on the inhabitants of the house for a time because of the suddenly increased number of mites that leave the bodies of the dead rats. Unfed protonymphs have been observed to survive for as long a period as 43 days without food (Sudd, 1952). Acaricides that depend on toxic action lose their toxicity too rapidly, particularly in the high summer temperatures of an attic. Reinfestation may then occur. HCN gas fumigation has been used successfully, but it is expensive and leaves no residue. The successful results of a fluorinated silica aerogel dust, blown into attics for the prevention of drywood termites (Incisitermes minor) suggested a similar use of this material for the control of the tropical rat mite (Ebeling, 1960). In 5 infested houses and 1 2-story apartment house, in each of which 1 or more inhabitants had been attacked by rat mites for prolonged periods, the silica aerogel Dri-die 67 was blown into the attic at the rate of 1 lb to 1,000 sq ft (0.45 kg to 93 sq m) of attic area. For 4 of the houses, the dust was also blown into the crawl space under the house at the same rate (for floor space) as that for the attic area. An electric duster with a 1-gal (4-L) hopper was used to apply the dust. In the attic, the dust was applied entirely from the crawl hole, and under the house, from 1 or 2 crawl holes or a larger number of foundation vents. Since in all cases the mites were already distributed throughout the dwelling, some dust was applied with a small bellows hand duster under mattresses, on the spring supports of beds, along the edges and in the 4 corners of bed frames, into the junctures of seats and back or arm rests and under the pillows of sofas and lounges, under furniture and other out-of-the way places, and in a few spots along the floor boards and ceiling moldings. The decision to make use of Dri-die 67 dust was made in an effort to bring about the immediate cessation of mite attacks. Principal reliance was placed on the dusting of the attic for longterm control. Rat mites may live as long as 63 days with no food (Scott, 1949), so those not coming into contact with the dust may continue to infest the inhabitants of a house. In all the buildings treated, severe infestations had been experienced up to the date of treatment, but ceased immediately afterward, and were never resumed except in 1 house where the housewife received a few more bites after treatment. In this instance, she applied more dust behind the electric outlet plates and various other areas that had not been covered the first time. Control was soon obtained, and no reinfestation occurred. Conventional liquid acaricides could have been applied in the living spaces of the treated houses, for people usually try to avoid leaving an unsightly residue. However, dusting is appropriate in attics, wall voids, and other inconspicuous areas. The dusting should be done before rat control is attempted, so that mites leaving the bodies of dead rats will contact the dust and will not be able to reach the living space and infest its occupants. house mouse mite, Liponyssoides sanguineus (Hirst) (= Allodermanyssus) (Macronyssidae) This mite occurs in northern Africa, Asia, Europe, and the United States. Although the house mouse (Mus musculus) is its preferred host, it will also feed on rats and other rodents. The house mouse mite attacks man, and causes a dermatitis in about the same way as does the tropical rat mite. Importantly, there is also considerable circumstantial evidence that it can transmit rickettsial pox, caused by Rickettsia akari (Baker et al., 1956). Description. Unengorged mites are 0.65 to 0.75 mm long, and engorged females may reach a length of 1 mm or more. Their color may range from red to blackish, depending on how recently blood meals have been taken; they cause the mites to appear black. This species has 2 dorsal plates on the adult female, but even on unengorged specimens, the plates do not cover the entire dorsal surface. The anterior plate on the dorsum is 10 times larger than the posterior plate, and bears several pairs of setae, whereas the posterior plate bears only 1 pair. The chelicerae are long and whiplike (Baker et al., 1956). Life Cycle. As with most macronyssid mites, there is an egg, larva, protonymph, deutonymph, and adult stage. Unlike the tropical rat mite, both protonymph and deutonymph require blood meals. The life cycle occupies 17 to 23 days, and unfed females have been observed to live as long as 51 days. The adult mite leaves its host after feeding, and may be found crawling about in mouse nests, runways, or on the walls and ceilings of infested buildings (Baker et al., 1956). Control. Control measures are the same as for the tropical rat mite. northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago) (Macronyssidae) This species (figure 312) is an ectoparasite of domestic fowls and many wild birds, but in the absence of bird hosts it will sometimes attack humans, causing an itch. It is similar to the tropical rat mite in appearance and life cycle. It can become a household pest when birds build nests under eaves of a house or in the attic. For control, these nests should be removed. Otherwise, treatment is the same as that recommended for control of the tropical rat mite. chicken mite, Dermanyssus gallinae (De Geer) (Dermanyssidae) This cosmopolitan species is a pest of poultry and wild birds. Poultry roosts or bird nests can be sources of home infestations, and the human occupants can also be infested. The bite of this mite causes painful skin irritation. Unfed adult mites are about 0.75 mm long and nearly white (figure312). After a blood meal, they may become 1 mm long and bright red. The female oviposits in crevices or under debris in chickenhouses or bird nests. Under favorable conditions, the entire life cycle may require only 7 days. The adults can survive without blood meals for 4 or 5 months (Baker et al., 1956). Chicken mites have been controlled by spraying the chickenhouse with l% malathion or by dusting infested litter with 2%, malathion dust at the rate of 1 lb to 20 sq ft (0.45 kg to 1.85 sq m) (Furman et al., 1955). human itch mite, Sarcoptes scabiei var. hominis (Hering) (Sarcoptidae) Different varieties of Sarcoptes scabiei (De Geer) are believed to be specific for different mammals, including man and a large variety of domestic and wild animals, but are transferable from one host to another. The variety specific to man is generally referred to as the "itch" or "scab" mite, and acariasis caused by it is sometimes called "scabies." People are most likely to become infested when living in continually crowded quarters, such as slums or jails, or during periods of major calamities that result in prolonged overcrowding. The human itch mite has a legitimate claim to fame in the history of biology. The original description of the life cycle and habits of this mite and the proof that it was the cause of scabies were accomplished by the Italian pharmacist Diacinto Cestoni and the relatively obscure young physician Giovan Cosino Bonomo. This was in the seventeenth century, when endo- and ectoparasites were usually considered to be produced by spontaneous generation. The observations made by Cestoni and Bonomo became generally known through a letter written by Bonomo to Francesco Redi (1626-1697), an experimental entomologist best known as a debunker of the "spontaneous generation" myth. The letter was reproduced in facsimile by Lane (1928). It has been described as "the birth certificate of parasitology" (Sadun, 1969). Buxton (1921a) made a detailed study of the external anatomy of the equine itch mite, Sarcoptes scabiei var. equi (Gerlach, 1857). A subsequent study of the anatomy of the human itch mite, Sarcoptes scabiei De Geer, 1778, var. hominis (Hering, 1880), revealed certain minute differences in scales and spines, but these differences were not constant and measurements overlapped. Buxton (1921 b) concluded that it was convenient to regard the 2 forms as varieties, but that this was more justifiable on physiological than on morphological grounds. For practical purposes, Buxton's (1921a) drawings and descriptions of the variety equi serve for the variety hominis. Heilesen (1946) made a detailed study of the anatomy of all stages of hominis, as well as an investigation of the biology of the species scabiei. Description. Itch mites (figure 313) are broadly oval, somewhat hemispherical, and so small that even the adults are barely visible to the unaided eye. Adult females are 0.33 to 0.45 mm long, and the males, 0.20 to 0.24 mm. The mites are a translucent, dirty-white color, with the more highly chitinized portions brownish. The integument is finely striate over most of its surface. In living specimens, the body is seen to be divided into 2 regions by a fold in the integument; the posterior portion bears the last 2 pairs of the 4 pairs of very short legs. The last 2 pairs of legs do not extend as far as the margins of the body. The anterior 2 pairs of legs on females and all but the third pair on males are provided with delicate, stalked, terminal suction pads. In the females the posterior 2 pairs of legs, and in the males the third pair, terminate in bristles. The adults lack eyes and many special respiratory organs. Characteristic spines and bristles on the dorsal surface aid in identifying the species. The spines are directed backward, and may serve to anchor the mite in position when it is digging burrows in the skin (Munro, 1919; Buxton, 1941b; Hand, 1946; Heilesen, 1946). Life Cycle. Both sexes and all stages of the itch mite tend to burrow into the skin immediately when placed on it, but the nymphs and males make only small, temporary holes, and move about frequently. The largest and longest burrows are made by the egg-laying female. The female always burrows in folds of the skin, preferring the deeper furrows and cracks. She can be induced to enter when a fine scratch has been made with a needle in the surface of the skin. She may also place herself in the acute angle between a sloping hair and the surface of the skin to gain support for initiating the burrowing (Heilesen, 1946). The winding burrow may reach a length of 5 to 15 mm. It is excavated in the deeper part of the horny epidermal layer, rarely as far as the granular layers (Buxton, 1941b; Heilesen, 1946). Munro (1919) believed that, if undisturbed, the female would lay all her eggs in 1 burrow (figure 313). A second mating does not take place; she dies in the burrow. It appears from the observations of various authors that the adult life of the mite is from 2 to as many as 6 weeks. It is difficult to determine the number of eggs laid by a female in her lifetime, but it is usually estimated to be between 40 and 50. Munro also observed that the period between the beginning of burrow formation and the finding of the first larva varied from 71 to 78 hours. He also found that 9 eggs removed from burrows and kept at 29 °to 30 °C (about 85 °F) hatched in 68 to 80 (average 74) hours. He gave the following numbers of days for the duration of the various life stages of the female: egg, 2.5 to 3.5; larva, 1.5 to 3; first nymph, 1.5 to 2.5; and second nymph, 2 to 4. He concluded that the life cycle required from 9 to 15 days. The numbers of days for the various life stages of the female, as determined by Heilesen (1946), were as follows: egg, 3 to 4; larva, 3; first nymph, 3 to 4; second nymph, 3 to 4; and from copulation to oviposition, 2; a total of 14 to 17 days. The developmental period for the male was only 9 to 11 days. The male has only 1 nymphal stage, whereas 2 are recognized in the female. In the second nymphal stage, the female can be fertilized by the male, even though the orifice (tocoptome) by which the eggs are laid has not yet been formed (Warburton, 1920). Means of Transmission. The ease of transmission of body lice via infested clothing and bedding has led many people to assume that itch mites could be transmitted in the same way. An important difference, however, is that body lice live on their host's clothes and contact his body only to feed, whereas itch mites spend most of their lives beneath the host's skin. In experiments with 63 male volunteers, in none of 31 men were itch mites transferred via blankets previously used by infested men, and in only 2 cases out of 32 were mites transmitted when uninfested men used underclothing immediately after it had been used by infested men (Mellanby, 1941). Merely putting clothing away for 2 or 3 days at ordinary room temperature should be sufficient to rid it of mites. Two persons in a bed gave the greatest opportunity for the spread of itch mites. However, transmission is also possible through "dancing, flirtation, and ordinary intimate contact between members of a family" (Heilesen, 1946). Body Regions Infested. Munro (1919) observed the burrowing procedures of egg-bearing females. The suckers of a female's anterior pair of legs were fixed onto the skin, and she propped her body up with the bristles on her posterior pair, assuming an almost perpendicular position. With her chelate mouthparts she commenced to cut the skin and bore in, becoming completely concealed in as little as 2.5 minutes. (This was a much shorter period than the one recorded by Heilesen, who found that 6 adult females burrowed into his skin in 15 to 40 minutes.) She ceased burrowing at a low temperature or when the body of her host was cold, and recommenced with a slight rise in temperature or warming of the body. Munro was able to activate burrowing of female mites in his wrist by passing from a cold room to a warm one, and was able to regulate the rate of burrowing by alternately warming and cooling an infested wrist over a radiator or other source of heat. He observed that under normal conditions, the burrowing period corresponded more or less to the time spent in bed. He stated: The parts of the body selected by the ovigerous female are the interdigital spaces; the wrists and the ulnar margins of the wrists; the elbows and the anterior folds of the axillae; the penis, scrotum, and buttocks; the back of the knee; and the ankles and toes. In young children, the egg burrows may occur on any part of the body, and in women, the undersides of the breasts are very commonly selected. Localization of Infestation. In an examination of 886 soldiers, 9,978 adult female mites were found and removed, an average of slightly over 11 per patient. About 52%, had fewer than 6 mites and only 3.9% had more than 50. One patient had 511. The percentages of mites found in the various areas of the body were: hands and wrists, 63.1; elbows (extensor aspect), 10.9; feet and ankles, 9.2; penis and scrotum, 8.4; buttocks, 4.0; axillae, 2.4; and in the remaining regions of the body, a total of 2 (Johnson and Mellanby, 1942). In another investigation, among 119 women the percentages of mites in various body areas were as follows: hands and wrists (excluding palms), 74.3%; palms of hands, 7.5% (none were found on the palms of men); elbows, 5.8; feet and ankles, 8.8; buttocks, 1.1; and in all other areas, 2.5. Among 18 children, itch mites were found to be more uniformly spread over many parts of the body, As indicated by Munro (1919), with many mites on their ankles and feet (Hartley and Mellanby, 1944). Active stages of mites confined in cells on parts of the body other than the foregoing will burrow into these parts, but if the cells are removed, they will leave them for the nearest sites usually selected. When Munro confined female mites on his forearm, they always burrowed into his skin enough for concealment, but left these burrows and were recovered on the wrist in from 20 minutes to 2.5 hours. Symptoms of Infestation. Whereas in animals large numbers of mites give rise to "sarcoptic mange," in humans relatively small numbers of mites can cause unpleasant symptoms, and the disease is known as "scabies." At a certain stage, the irritation may become so severe that the patient becomes frantic and suffers from lack of sleep. If the infestation is long continued, or if a later infestation occurs, an allergic reaction develops, with intense itching and a redness, or rash of follicular papules over much of the body. The rash may develop on areas such as around the armpits, the wrists, the waist, inside the thighs, and backs of the calves, but these areas do not necessarily coincide with those of mite infestation. The rash may occur over much of the body, even though only a few mites may be present in restricted locations between the fingers (Pratt, 1963). In an investigation of 55 volunteers who had not been infested with itch mites before, Mellanby (1944) observed that during the first month of itch mite infestation, there were few or no symptoms and no erythema. Infested persons might even be unaware that mites were burrowing into their skin. Symptoms began to be evident in about a month, and in about 6 weeks the irritation was sufficiently severe to cause some loss of sleep. Then the itching grew progressively worse, and after 100 days it was practically continuous and almost unbearable. However, when secondary infections and impetigo developed, the mite population decreased, and was sometimes completely eliminated. (If secondary infections are neglected, they may themselves require prolonged medical treatment.) When volunteers already infested were treated and then reinfested, intense local irritation was felt within 24 hours, and a patch of erythema surrounded each mite. This apparently caused an adverse environment for the mites, for in another 2 days most of them had disappeared, some scratched out by the patient and others leaving the burrow. Relatively few mites reached maturity when compared with the original infestation. Medical Treatment. It is important to diagnose scabies correctly, for neither the irritation nor the liability to skin diseases can cease until the mites have been eliminated. Look for the burrow of a female in such places as between the knuckles and in folds of the wrist and elbow, and then gently prick the burrow open. Toward the end of the burrow, the mite can usually be distinguished as a dull-white spot. Remove it with a needle. A bath before treatment is desirable for hygienic reasons. Thorough treatment is essential, and is best done by a physician or a reliable nurse or orderly. Treatment consists of application of ointments or liquid preparations. Ramsay (1969) prescribed either 25% benzyl benzoate emulsions, Kwell® (1 % lindane) cream or lotion, or Eurax® cream or lotion. The latter contains 10% of crotamiton (N-ethyl-o-crotonotoluide). Ramsay recommended that these preparations be applied in the evening after the patient had taken a warm bath, and that the application be left in place until the next evening, when the treatment would be repeated. All areas of the skin below the neck should be treated, including body folds, palms, and soles. A cleansing bath should be taken 48 hours after the second application. Some tingling of the skin is to be expected after treatment, and it may last as long as 10 to 14 days. Calamine lotion or emulsion may be applied to alleviate this condition. Instructions on the package in which the medication is sold should always be read and followed carefully. Secondary infections may require the skills of a medical doctor or dermatologist. If the treatment is satisfactory and reinfestation occurs, an effort should be made to find untreated persons with whom the patient may have had contact. canine mange mite, Sarcoptes scabiei var. canis Gerlach, on Dogs and Humans Sarcoptes scabiei on domestic animals has generally been referred to as a sarcoptic mange mite, and the symptom as "mange" or "scabies." The mite causes a self-limiting but very uncomfortable eruption if the secondary host is human. Man is particularly vulnerable to infestation by the variety of mange mite that infests the dog, probably because of his closer association with that animal than with others. Description. This broadly oval mite is very small about the size of the human itch mite. As in the human itch mite, in both sexes the anterior 2 pairs of legs and, in the male, also the fourth pair, have delicate, terminal, stalked suction pads. In the females, the posterior 2 pairs of legs, and in the males the third pair, end in bristles. Characteristic spines and bristles on the dorsal surface aid in identifying the species. Life Cycle. The female lays her eggs in burrows she makes in the skin. They hatch in 3 to 5 days, and a complete life cycle requires 8 to 17 days (Smith and Claypoole, 1967). Symptoms on Dogs. The eruption begins with small, white or erythematous (reddish, inflamed) papules, initially appearing, in the groin and "armpit" areas and on the periphery of the ears. The papules may become so numerous that they appear to be contiguous, especially on the relatively hairless portions of the body. Crusts form, composed of dried exudates of serum and blood. The skin becomes lichenous, scaly, and corrugated in appearance. The eruption spreads, but is usually most severe on the ears, head, abdomen, and in groin and "armpit" areas. Hair is lost, or can be easily pulled out in patches. The remaining hair becomes dull and lusterless, and the animal develops a characteristic "mousey" odor. Intense generalized itching accompanies the eruption, and if untreated, the animal may become emaciated and even die of exhaustion from the itching and extensive chronic inflammatory reaction, often with a secondary infection. Canine scabies occurs most commonly in undernourished puppies, particularly if they are suffering from internal parasites (Smith and Claypoole, 1967). Symptoms on Humans. A rash develops on some persons after only brief contact with an infested dog, but the most severe cases develop in those with prolonged close contact. The eruption is most often in the form of pimples, but may be characterized by blisters and inflammation. There is frequently a sloughing away of the skin. Lesions are most common on the forearms, lower region of the chest, and on the abdomen and thighs, but may be generalized. The distribution of symptoms usually differs from that of human scabies, in that the finger webs and the genitalia are usually not affected, but both these areas may be involved if the infestation is severe. The face is not affected except in children. In view of the facts that (1) the sarcoptic mite can live for 4 to 5 weeks, (2) in no cases have symptoms lasted longer than this, and (3) burrows have not been found in human skin it appears that Sarcoptes scabiei var. canis does not reproduce on human skin, but this could be definitely proved only by prolonged observation on heavily infested human volunteers - an unlikely development (Smith and Claypoole, 1967). Control of Mange on Dogs. In mange or scabies control on dogs, advantage has been taken of the fact that male mites do not do any significant boring into the skin, and may be controlled by continuous exposure to toxic vapors. In one experiment, a dichlorvos resin strip (NO-Pest Strip¨) was placed in the bedding inside the doghouse of a beagle, 3 x 1.5 x 2 ft (90 x 45 x 60 cm) in area. Within 2 weeks, the dog's skin, which had been red on the lower half of the body and on the legs from a severe case of sarcoptic mange, lost its redness, and new hair began to appear. The strip was moved to one side of the doghouse, and the dog's condition continued to improve; he recovered completely in 6 weeks. Whereas mites were taken from all skin scrapings before treatment, none were taken 6 weeks later. The dog had chewed the edges of the dichlorvos strip, but no ill effect was noted (Whitney, 1969). The specialist who conducted this experiment had used dichlorvos resin strips for several years to protect dogs and cats from flies and mosquitoes, and had observed no sarcoptic mange or fleas on 60 beagles and 36 cats that had been kept in kennels and a cat room where the strips had been used. Treatment for Scabies or Mange. Both dogs and humans have been effectively treated with "gamma benzene hexachloride cream." Humans were cured with 1 application. The patient should avoid further close contact with the pet until it is cured (Smith and Claypoole, 1967). The old NBIN lotion for a combination treatment for lice and scabies (Eddy, 1946) is still available under the name of Topocide, but may be procured by prescription only. Figure 303. Cat flea, Ctenocephalides felis. A, adult; B, larvae; C, eggs; D, larva in cocoon; E, pupa in cocoon. Figure 304. The pajaroello, Ornithodoros coriaceus. Figure 305. External morphological features of hard ticks (Ixodidae). A, ventral aspect of capitulum; B, dorsal aspect of female; C, ventral aspect of male; D, leg. (From Pratt and Littig, 1962.) Figure 306. American dog tick, Dermacentor variabilis. A, dorsal aspect of larva; B, nymph; C, adult male; D, adult unengorged female. (From Smith et al., 1946.) Figure 307. Engorged female of the American dog tick, Dermacentor variabilis. (From Smith et al., 1946.) Figure 308. Brown dog tick, Rhipicephalus sanguineus Figure 309. A chigger mite, Trombicula batatas. A, unengorged larva; B, engorged larva; C, nymph; D, ventral view of preadult; E, adult. (From Michener, 1946.) Figure 310, Straw itch mite, Pyemotes ventricosus. From left, male; female; gravid female. (From Fine.and Scott, 1963.) Figure 311. Back and neck of a woman, showing maculae caused by bites of the tropical rat mite, Ornithonyssus bacoti. Inset: Engorged mite. (From Ebeling, 1960.) Figure 312. Northern fowl mite, Ornithonyssus sylviarum (left), and chicken mite, Dermanyssus gallinae. Figure 313. Top, dorsal and ventral views of the human itch mite, Sarcoptes scabiei var. hominis. Left, female; right, male; bottom, egg burrow with 9 eggs and a female mite at the end of the burrow. (Arranged from.Munro, 1919).
What is the Art of Play? Play is an essential part of learning for children (and adults!). By engaging in the art of play, young children learn through both imagining and doing, which directly simulates their brain to support positive cognitive development, social-emotional learning, and physical well-being. How Play Effects the Brain According to the The Art of Play infographic from Wooden ToyShop, play-based learning can: - Simulate growth of the cerebral cortex (the area of the brain responsible for higher-level thinking skills). - Improve memory and attention span. - Help children feel happy and fulfilled. - Encourage cognitive development and brain growth. - Establish neurological connections. - Increase the ability to learn and succeed academically. - Increase problem solving abilities. Stages of Socialization During Play Toddlers like to play on their own. This teaches a child how to keep themselves entertained and promotes self-learning. This is when a child watches other children playing around them. Onlooker play allows the child to develop early-literacy skills, like vocabulary, and to learn from others by mimicking their actions. When children of the same age play in the same room but not together, they learn social skills such as taking turns. When children work together to build a block tower or play a game, it helps them build social skills such as teamwork, negotiation, and cooperation. Dressing-up as a doctor, or pretending to be a superhero, helps children develop creativity and social-emotional skills necessary for problem solving. Competition allows children to understand the rules, and how to win and lose. This is important both for goal setting, perseverance, and social-emotional development. Active play whether throwing a ball or riding a bike, helps promote children’s health and physical development, such as fine and gross motor skills. Playing with manipulatives like toy trains and building blocks teaches children how things fit together and how to manipulate objects with their hands. These fine more skills are important for future development of handwriting.[sc: inlinead] Research Findings about the Benefits of Play Children naturally want to explore their world. - 20% of playtime is spent doing physical activities. In research studies, while children play with blocks, - 88% of the time, they are engaged in math, such as developing early numeracy skills, like counting. Elementary school students that have - 15 minutes of recess per day are better behaved.
Assessing the potential contribution of carbon capture and storage (CCS) to limiting climate change must take into account the huge physical scale of the materials being captured and transported. In my previous post I looked at the slow growth of carbon capture and storage (CCS) and carbon capture and use (CCU). In this post I look at the scale of CO2 that needs to be captured to make a material difference to the climate, and some of the implications of this. As reference points, the chart below shows annual production of major commodities. The mass of fossil fuels produced and consumed each year is huge – about 12 billion tonnes every year, over one and a half tonnes for each person in the world. That is much more than other major commodities. Wheat is less than a billion tonnes per annum, the iron ore for the world’s iron and steel industry is a little over two billion tonnes, and cement is something over four billion tonnes. However the CO2 produced from energy and industry (so excluding land use), is much greater still – about 36 billion tonnes. The vast majority of this comes ultimately from the world’s fossil fuels. Very simply, the mass of the fossil fuels is mainly carbon, and burning this carbon adds two atoms of oxygen to each atom of carbon, more than tripling the mass, hence the scale of the mass of CO2 produced relative to fossil fuels. Chart: annual production of major commodities[i] Even capturing and transporting around a third of current emissions would involve dealing with masses as large as the current fossil fuel system, which has required, cumulatively, tens of trillions of dollars of investment over many decades. Many low carbon technologies have faced similar challenge of scale. For example, it has taken decades to get wind power to the scale where it is making a material difference to emissions. The problem gets even worse for any process of CO2 capture from the air that involves use of a solid to bind the CO2. This is because binding CO2 as a solid inevitably involves adding mass. For example, if theCO2 were eventually to end up as limestone (CaCO3) the limestone would have more than double the mass of the captured carbon dioxide. This is especially important for some of the proposals for removing carbon dioxide from the atmosphere by direct air capture into solid form. To make any worthwhile reduction in atmospheric concentration hundreds of billions of tonnes of solid material will be eventually be generated. For this reason it is often considered that air capture is best located the source of the scrubbing mineral and where it can be easily disposed of, but the masses involved are nevertheless huge and handling remains a huge problem. The challenges raised by the mass of CO2 produced by energy use extends to the development of more localised technologies. Suppose, for example a new technology were invented for carbon capture, capable of cheaply absorbing and binding in solid form CO2 produced by a standard domestic heating boiler. A typical UK household burns about 16,500 kWh of gas per annum[ii], which generates about 3.3 tonnes of CO2. Any attempt to capture this would produce many tonnes of material a year to be disposed of. This compares with current total waste per household at present of around 1 tonne per household. Alternatively, if household CO2 capture were based around solvents to regenerated while the CO2 is piped away, this would require huge amounts of new pipeline infrastructure. This is unlikely to be practical. Instead any CCS is likely to be deployed centrally, for example as part of low carbon hydrogen production, with the hydrogen burnt to produce heat, or for production of low carbon electricity. The vast scale of CO2 emissions has several implications. First, it will usually be much better to avoid creating the CO2 in the first place than to try to deal with it as a waste problem. The waste problem is already too big to handle, so adding more in the hope of being able to deal with it is not likely to be the best option. Second, any system that does make a material contribution to reducing climate change will take vast investment and many years to build – which is a good reason for starting now. Third, making CCS and CCU more economically viable would help, and this is one of many reasons that higher carbon prices are desirable. There are however two important caveats to this. One is that land use does have an important contribution to make. The scale of release of CO2 from land use and, correspondingly, the potential benefits from reducing deforestation and improving management of biological sinks are large. However, as I’ve previously noted, there are limits on the availability of biofuels. The other caveat is that all contributions to reducing emissions are welcome, and there may be cases, especially in industry, where there are few if any alternatives to capture. Reducing emissions will require a very large range of technologies to be deployed. Nothing I’ve said in this post should be taken as a reason for not proceeding with CCS or CCU. As I noted in my previous post CCS continues to look necessary in a range of applications. And building an industry at the scale required will take decades, and there is an urgent need for progress. It is imperative to recognise just how large the physical scale of the challenge is, even relative to other economic activities such as iron and steel production often (rightly) thought to be very large scale. Adam Whitmore – 21st May 2018 [i] Based on data in the BP statistical review of world energy, UN Food and Agriculture organisation, EDGAR database, USGS, http://www.worldcement.com. The ratio of fuels to carbon dioxide is not exactly the same as the ratio of the masses of carbon to CO2, which is 3.7, because of the other components in fossil fuels. The CO2 total includes emissions from industrial processes in addition to combustion. However many non-combustion emissions, such as the use of carbon in anodes from aluminium smelting, and (depending on your definition of combustion) the use of coke in blast furnaces also use fossil fuels as their source of carbon. [ii] Source Ofgem
Cancer refers to any one of a large number of diseases characterized by the development of abnormal cells that divide uncontrollably and have the ability to infiltrate and destroy normal body tissue. Cancer often has the ability to spread throughout your body. Cancer is the second-leading cause of death in the world. But survival rates are improving for many types of cancer, thanks to improvements in cancer screening and cancer treatment. Signs and symptoms caused by cancer will vary depending on what part of the body is affected. Some general signs and symptoms associated with, but not specific to, cancer, include: - Lump or area of thickening that can be felt under the skin - Weight changes, including unintended loss or gain - Skin changes, such as yellowing, darkening or redness of the skin, sores that won't heal, or changes to existing moles - Changes in bowel or bladder habits - Persistent cough or trouble breathing - Difficulty swallowing - Persistent indigestion or discomfort after eating - Persistent, unexplained muscle or joint pain - Persistent, unexplained fevers or night sweats - Unexplained bleeding or bruising When to see a doctor Make an appointment with your doctor if you have any persistent signs or symptoms that concern you. If you don't have any signs or symptoms, but are worried about your risk of cancer, discuss your concerns with your doctor. Ask about which cancer screening tests and procedures are appropriate for you. Cancer is caused by changes (mutations) to the DNA within cells. The DNA inside a cell is packaged into a large number of individual genes, each of which contains a set of instructions telling the cell what functions to perform, as well as how to grow and divide. Errors in the instructions can cause the cell to stop its normal function and may allow a cell to become cancerous. What do gene mutations do? A gene mutation can instruct a healthy cell to: - Allow rapid growth. A gene mutation can tell a cell to grow and divide more rapidly. This creates many new cells that all have that same mutation. - Fail to stop uncontrolled cell growth. Normal cells know when to stop growing so that you have just the right number of each type of cell. Cancer cells lose the controls (tumor suppressor genes) that tell them when to stop growing. A mutation in a tumor suppressor gene allows cancer cells to continue growing and accumulating. - Make mistakes when repairing DNA errors. DNA repair genes look for errors in a cell's DNA and make corrections. A mutation in a DNA repair gene may mean that other errors aren't corrected, leading cells to become cancerous. These mutations are the most common ones found in cancer. But many other gene mutations can contribute to causing cancer. What causes gene mutations? Gene mutations can occur for several reasons, for instance: - Gene mutations you're born with. You may be born with a genetic mutation that you inherited from your parents. This type of mutation accounts for a small percentage of cancers. - Gene mutations that occur after birth. Most gene mutations occur after you're born and aren't inherited. A number of forces can cause gene mutations, such as smoking, radiation, viruses, cancer-causing chemicals (carcinogens), obesity, hormones, chronic inflammation and a lack of exercise. Gene mutations occur frequently during normal cell growth. However, cells contain a mechanism that recognizes when a mistake occurs and repairs the mistake. Occasionally, a mistake is missed. This could cause a cell to become cancerous. How do gene mutations interact with each other? The gene mutations you're born with and those that you acquire throughout your life work together to cause cancer. For instance, if you've inherited a genetic mutation that predisposes you to cancer, that doesn't mean you're certain to get cancer. Instead, you may need one or more other gene mutations to cause cancer. Your inherited gene mutation could make you more likely than other people to develop cancer when exposed to a certain cancer-causing substance. It's not clear just how many mutations must accumulate for cancer to form. It's likely that this varies among cancer types. While doctors have an idea of what may increase your risk of cancer, the majority of cancers occur in people who don't have any known risk factors. Factors known to increase your risk of cancer include: Cancer can take decades to develop. That's why most people diagnosed with cancer are 65 or older. While it's more common in older adults, cancer isn't exclusively an adult disease — cancer can be diagnosed at any age. Certain lifestyle choices are known to increase your risk of cancer. Smoking, drinking more than one alcoholic drink a day (for women of all ages and men older than age 65) or two drinks a day (for men age 65 and younger), excessive exposure to the sun or frequent blistering sunburns, being obese, and having unsafe sex can contribute to cancer. You can change these habits to lower your risk of cancer — though some habits are easier to change than others. Your family history Only a small portion of cancers are due to an inherited condition. If cancer is common in your family, it's possible that mutations are being passed from one generation to the next. You might be a candidate for genetic testing to see whether you have inherited mutations that might increase your risk of certain cancers. Keep in mind that having an inherited genetic mutation doesn't necessarily mean you'll get cancer. Your health conditions Some chronic health conditions, such as ulcerative colitis, can markedly increase your risk of developing certain cancers. Talk to your doctor about your risk. The environment around you may contain harmful chemicals that can increase your risk of cancer. Even if you don't smoke, you might inhale secondhand smoke if you go where people are smoking or if you live with someone who smokes. Chemicals in your home or workplace, such as asbestos and benzene, also are associated with an increased risk of cancer. Cancer and its treatment can cause several complications, including: - Pain. Pain can be caused by cancer or by cancer treatment, though not all cancer is painful. Medications and other approaches can effectively treat cancer-related pain. - Fatigue. Fatigue in people with cancer has many causes, but it can often be managed. Fatigue associated with chemotherapy or radiation therapy treatments is common, but it's usually temporary. - Difficulty breathing. Cancer or cancer treatment may cause a feeling of being short of breath. Treatments may bring relief. - Nausea. Certain cancers and cancer treatments can cause nausea. Your doctor can sometimes predict if your treatment is likely to cause nausea. Medications and other treatments may help you prevent or decrease nausea. - Diarrhea or constipation. Cancer and cancer treatment can affect your bowels and cause diarrhea or constipation. - Weight loss. Cancer and cancer treatment may cause weight loss. Cancer steals food from normal cells and deprives them of nutrients. This is often not affected by how many calories or what kind of food is eaten; it's difficult to treat. In most cases, using artificial nutrition through tubes into the stomach or vein does not help change the weight loss. - Chemical changes in your body. Cancer can upset the normal chemical balance in your body and increase your risk of serious complications. Signs and symptoms of chemical imbalances might include excessive thirst, frequent urination, constipation and confusion. - Brain and nervous system problems. Cancer can press on nearby nerves and cause pain and loss of function of one part of your body. Cancer that involves the brain can cause headaches and stroke-like signs and symptoms, such as weakness on one side of your body. - Unusual immune system reactions to cancer. In some cases the body's immune system may react to the presence of cancer by attacking healthy cells. Called paraneoplastic syndrome, these very rare reactions can lead to a variety of signs and symptoms, such as difficulty walking and seizures. - Cancer that spreads. As cancer advances, it may spread (metastasize) to other parts of the body. Where cancer spreads depends on the type of cancer. - Cancer that returns. Cancer survivors have a risk of cancer recurrence. Some cancers are more likely to recur than others. Ask your doctor about what you can do to reduce your risk of cancer recurrence. Your doctor may devise a follow-up care plan for you after treatment. This plan may include periodic scans and exams in the months and years after your treatment, to look for cancer recurrence. There's no certain way to prevent cancer. But doctors have identified several ways of reducing your cancer risk, such as: - Stop smoking. If you smoke, quit. If you don't smoke, don't start. Smoking is linked to several types of cancer — not just lung cancer. Stopping now will reduce your risk of cancer in the future. - Avoid excessive sun exposure. Harmful ultraviolet (UV) rays from the sun can increase your risk of skin cancer. Limit your sun exposure by staying in the shade, wearing protective clothing or applying sunscreen. - Eat a healthy diet. Choose a diet rich in fruits and vegetables. Select whole grains and lean proteins. - Exercise most days of the week. Regular exercise is linked to a lower risk of cancer. Aim for at least 30 minutes of exercise most days of the week. If you haven't been exercising regularly, start out slowly and work your way up to 30 minutes or longer. - Maintain a healthy weight. Being overweight or obese may increase your risk of cancer. Work to achieve and maintain a healthy weight through a combination of a healthy diet and regular exercise. - Drink alcohol in moderation, if you choose to drink. If you choose to drink alcohol, limit yourself to one drink a day if you're a woman of any age or a man older than age 65, or two drinks a day if you're a man 65 years old or younger. - Schedule cancer screening exams. Talk to your doctor about what types of cancer screening exams are best for you based on your risk factors. - Ask your doctor about immunizations. Certain viruses increase your risk of cancer. Immunizations may help prevent those viruses, including hepatitis B, which increases the risk of liver cancer, and human papillomavirus (HPV), which increases the risk of cervical cancer and other cancers. Ask your doctor whether immunization against these viruses is appropriate for you. Diagnosing cancer at its earliest stages often provides the best chance for a cure. With this in mind, talk with your doctor about what types of cancer screening may be appropriate for you. For a few cancers, studies show screening tests can save lives by diagnosing cancer early. For other cancers, screening tests are recommended only for people with increased risk. A variety of medical organizations and patient-advocacy groups have recommendations and guidelines for cancer screening. Review the various guidelines with your doctor and together you can determine what's best for you based on your own risk factors for cancer. Your doctor may use one or more approaches to diagnose cancer: - Physical exam. Your doctor may feel areas of your body for lumps that may indicate a tumor. During a physical exam, he or she may look for abnormalities, such as changes in skin color or enlargement of an organ, that may indicate the presence of cancer. - Laboratory tests. Laboratory tests, such as urine and blood tests, may help your doctor identify abnormalities that can be caused by cancer. For instance, in people with leukemia, a common blood test called complete blood count may reveal an unusual number or type of white blood cells. - Imaging tests. Imaging tests allow your doctor to examine your bones and internal organs in a noninvasive way. Imaging tests used in diagnosing cancer may include a computerized tomography (CT) scan, bone scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scan, ultrasound and X-ray, among others. Biopsy. During a biopsy, your doctor collects a sample of cells for testing in the laboratory. There are several ways of collecting a sample. Which biopsy procedure is right for you depends on your type of cancer and its location. In most cases, a biopsy is the only way to definitively diagnose cancer. In the laboratory, doctors look at cell samples under the microscope. Normal cells look uniform, with similar sizes and orderly organization. Cancer cells look less orderly, with varying sizes and without apparent organization. Once cancer is diagnosed, your doctor will work to determine the extent (stage) of your cancer. Your doctor uses your cancer's stage to determine your treatment options and your chances for a cure. Staging tests and procedures may include imaging tests, such as bone scans or X-rays, to see if cancer has spread to other parts of the body. Cancer stages are generally indicated by Roman numerals — I through IV, with higher numerals indicating more advanced cancer. In some cases, cancer stage is indicated using letters or words. Many cancer treatments are available. Your treatment options will depend on several factors, such as the type and stage of your cancer, your general health, and your preferences. Together you and your doctor can weigh the benefits and risks of each cancer treatment to determine which is best for you. Goals of cancer treatment Cancer treatments have different objectives, such as: - Cure. The goal of treatment is to achieve a cure for your cancer, allowing you to live a normal life span. This may or may not be possible, depending on your specific situation. Primary treatment. The goal of a primary treatment is to completely remove the cancer from your body or kill the cancer cells. Any cancer treatment can be used as a primary treatment, but the most common primary cancer treatment for the most common cancers is surgery. If your cancer is particularly sensitive to radiation therapy or chemotherapy, you may receive one of those therapies as your primary treatment. Adjuvant treatment. The goal of adjuvant therapy is to kill any cancer cells that may remain after primary treatment in order to reduce the chance that the cancer will recur. Any cancer treatment can be used as an adjuvant therapy. Common adjuvant therapies include chemotherapy, radiation therapy and hormone therapy. Palliative treatment. Palliative treatments may help relieve side effects of treatment or signs and symptoms caused by cancer itself. Surgery, radiation, chemotherapy and hormone therapy can all be used to relieve signs and symptoms. Medications may relieve symptoms such as pain and shortness of breath. Palliative treatment can be used at the same time as other treatments intended to cure your cancer. Doctors have many tools when it comes to treating cancer. Cancer treatment options include: - Surgery. The goal of surgery is to remove the cancer or as much of the cancer as possible. - Chemotherapy. Chemotherapy uses drugs to kill cancer cells. - Radiation therapy. Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation treatment can come from a machine outside your body (external beam radiation), or it can be placed inside your body (brachytherapy). Bone marrow transplant. Bone marrow transplant is also known as a stem cell transplant. Your bone marrow is the material inside your bones that makes blood cells. A bone marrow transplant can use your own cells or cells from a donor. A bone marrow transplant allows your doctor to use higher doses of chemotherapy to treat your cancer. It may also be used to replace diseased bone marrow. - Immunotherapy. Immunotherapy, also known as biological therapy, uses your body's immune system to fight cancer. Cancer can survive unchecked in your body because your immune system doesn't recognize it as an intruder. Immunotherapy can help your immune system "see" the cancer and attack it. - Hormone therapy. Some types of cancer are fueled by your body's hormones. Examples include breast cancer and prostate cancer. Removing those hormones from the body or blocking their effects may cause the cancer cells to stop growing. - Targeted drug therapy. Targeted drug treatment focuses on specific abnormalities within cancer cells that allow them to survive. - Clinical trials. Clinical trials are studies to investigate new ways of treating cancer. Thousands of cancer clinical trials are underway. Other treatments may be available to you, depending on your type of cancer. No alternative cancer treatments have been proved to cure cancer. But alternative medicine options may help you cope with side effects of cancer and cancer treatment, such as fatigue, nausea and pain. Talk with your doctor about what alternative medicine options may offer some benefit. He or she can also discuss whether these therapies are safe for you or whether they may interfere with your cancer treatment. Some alternative medicine options found to be helpful for people with cancer include: - Relaxation techniques A cancer diagnosis can change your life forever. Each person finds his or her own way of coping with the emotional and physical changes cancer brings. But when you're first diagnosed with cancer, sometimes it's difficult to know what to do next. Here are some ideas to help you cope: - Learn enough about cancer to make decisions about your care. Ask your doctor about your cancer, including your treatment options and, if you like, your prognosis. As you learn more about cancer, you may become more confident in making treatment decisions. - Keep friends and family close. Keeping your close relationships strong will help you deal with your cancer. Friends and family can provide the practical support you'll need, such as helping take care of your house if you're in the hospital. And they can serve as emotional support when you feel overwhelmed by cancer. Find someone to talk with. Find a good listener who is willing to listen to you talk about your hopes and fears. This may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or cancer support group also may be helpful. Ask your doctor about support groups in your area. Other sources of information include the National Cancer Institute and the American Cancer Society. Start by making an appointment with your family doctor if you have any signs or symptoms that worry you. If your doctor determines you have cancer, you'll likely be referred to one or more specialists, such as: - Doctors who treat cancer (oncologists) - Doctors who treat cancer with radiation (radiation oncologists) - Doctors who treat diseases of the blood and blood-forming tissues (hematologists) Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well-prepared. Here's some information to help you get ready, and know what to expect from your doctor. What you can do - Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet. - Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment. - Write down key personal information, including any major stresses or recent life changes. - Write down your family's history of cancer. If other members of your family have been diagnosed with cancer, make a note of the types of cancer, how each person is related to you and how old each person was when diagnosed. - Make a list of all medications, vitamins or supplements that you're taking. - Consider taking a family member or friend along. Sometimes it can be difficult to remember all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot. - Write down questions to ask your doctor. Your time with your doctor is limited, so preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. For cancer, some basic questions to ask your doctor include: - What type of cancer do I have? - What stage is my cancer? - Will I need additional tests? - What are my treatment options? - Can treatments cure my cancer? - If my cancer can't be cured, what can I expect from treatment? - What are the potential side effects of each treatment? - Is there one treatment you feel is best for me? - How soon do I need to begin treatment? - How will treatment affect my daily life? - Can I continue working during treatment? - Are there any clinical trials or experimental treatments available to me? - I have these other health conditions. How can I manage them during my cancer treatment? - Are there any restrictions that I need to follow? - Should I see a specialist? What will that cost, and will my insurance cover it? - Is there a generic alternative to the medicine you're prescribing? - Are there brochures or other printed material that I can take with me? What websites do you recommend? - What will determine whether I should plan for follow-up visits? In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask other questions that occur to you. What to expect from your doctor Your doctor is likely to ask you a number of questions. Being ready to answer them may allow time later to cover other points you want to address. Your doctor may ask: - When did you first begin experiencing symptoms? - Have your symptoms been continuous or occasional? - How severe are your symptoms? - What, if anything, seems to improve your symptoms? - What, if anything, appears to worsen your symptoms? - Does anyone in your family have cancer? - Have you ever had cancer before? If so, what kind and how was it treated? - Have you ever been exposed to chemicals at home or at work? - Do you smoke or use tobacco? - Have you ever been diagnosed with a hepatitis infection or a human papillomavirus infection?
Too much sunlight can cause sunburn, and sunburn is a risk factor for skin cancer. So, if sunscreens help prevent sunburn, they should reduce the risk of skin cancer too, right? It turns out, according to a piece appearing last month in the journal Clinical Pharmacology and Therapeutics, that the evidence that sunscreens protect against skin cancer turns out to be a bit thin on the ground . Skin cancers come in three main forms: the quite-often deadly malignant melanoma, as well as squamus cell carcinoma and basal cell carcinoma that are not nearly as life-threatening. The author of the Clinical Pharmacology and Therapeutics piece cites a randomised study in which individuals used daily sunscreen or no daily sunscreen for 4.5 years. The study looked only at squamous cell and basal cell carcinomas. The result was that the development of new cancers was essentially the same in both groups. In other words, the application of sunscreen did not appear to protect against the development of new skin cancers. Turning out attention for a moment to malignant melanoma, the article states: “Unfortunately, no melanoma study has shown convincingly that sunscreen use reduces the risk of melanoma.” The piece goes on to speculate why this might be. A few theories are put forward, which include: - The sorts of people who use sunscreen (e.g. fair-skinned) are generally at enhanced risk of skin cancer to begin with. - Sunscreens often protect against burning by blocking ultraviolet B (UVB) rays, but may allow longer exposure to potentially damaging rays from other parts of the spectrum such as UVA. - Many people who use sunscreens do not apply them properly. - Sunscreen may block the manufacture of vitamin D (which is linked to cancer-protective effects). This mechanism is viewed as of doubtful significance by the author, who refers to the fact this is only likely to an issue in those who apply the sunscreen properly. - The potentially carcinogenic effect of certain chemicals used in sunscreens including avobenzone (Parsol 1789) and ecamsule (Mexoryl SX). The article goes on to refer to the fact that “…interests that are not scientifically based seem to be driving the heavy reliance on sunscreens as the first line of prevention against skin cancer,” adding “The fervor with which companies promote sunscreen can perhaps be traced to the profit that sunscreen sales bring.” The piece also states: “Death from skin cancer is advertised as being avoidable with the use of sunscreens. This position might actually be true, but there is as yet absolutely no scientific evidence to support it.” For more information on safe sun exposure including the use of clothing and shade, see here. 1. Berwick M. The good, the bad and the ugly of sunscreens. Clinical Pharmacology and Therapeutics 2011;89(1):31-33
For many people on Earth — baseball is a favorite pastime. But how different would it be if home plate were on the moon? A reader from Texas asked, “If baseball were played on the moon, how far would the home run fences have to be from home plate?” Well, the moon’s gravity pulls with only about one-sixth the pull of earthly gravity. So a batter on the moon could send a baseball six times farther than the same baseball hit on Earth. If this were the only effect, the center field fence in a typical baseball stadium would have to be about six times farther away. But the moon doesn’t have an appreciable atmosphere — so there’s little or no air resistance on the moon. A baseball hit in our atmosphere travels only 60% as far as one hit in a vacuum. Since the moon’s atmosphere approximates a vacuum, you can increase the range of the ball hit on the moon again — this time by a factor of about 2. So a typical center field fence on the moon would need to be about 12 times farther than on Earth. What’s more, the tension might mount in lunar baseball when it came time to throw a pitch. Without air resistance, a fast ball would be really fast! On the other hand, a space suit might hinder a good wind up — and curve balls, which rely on air resistance, wouldn’t be possible. If you want to learn more about the mechanics of baseball this is an excellent book: Adair, Robert Kemp. The Physics of Baseball. (HarperCollins: New York, 1995).
Just as fruit require an inward flow of carbohydrate and water to provide for seed growth and pericarp expansion, so mineral nutrients are also supplied. As a rule, concentrations of the major mineral nutrients in fruit are lower than in other organs such as leaves, and the patterns of phosphorus, potassium, calcium, magnesium and nitrogen accumulation usually differ. Mineral nutrients move into the fruit most rapidly during the early stages of development (Figure 11.8) at a time when xylem water flow dominates. As fruit approach maturity, surface to volume ratio declines, the skin becomes less permeable to water loss, and large amounts of photoassimilate are imported via phloem connections. As a result, a significant part of the water reaching fruit now enters through the phloem and is accompanied by photoassimilate. Mobile ions such as K+ and HPO42– are loaded into the leaf veins along with the photoassimilate, travel in the phloem and so reach fruit over the whole growing season. In contrast, less mobile nutrients such as Ca2+ fail to reach fruit during later stages, so that Ca2+ concentration remains steady or even declines slightly (Figure 11.8). Nutrient deficiencies in fruit are relatively uncommon, except for those associated with calcium. Calcium deficiencies are expressed in the form of blossom-end rot in tomato, and bitter pit plus lenticel blotch in apple fruit. These apple disorders tend to be expressed during postharvest storage, but symptom expression is somehow related to the previous ripening environment. These disorders show up as a pitting of flesh and skin, reducing fruit value or even rendering those commodities unmarketable. Such commercial penalties have resulted in development of preharvest sprays and postharvest dips of calcium salts that diminish bitter-pit incidence in harvested fruit. Where there is little or no calcium recycling via phloem, calcium needs to be applied directly to fruit to have a beneficial effect.
About the Netherlands When the dikes broke The Netherlands’ battle to conquer water A stormy night in February, 1953. A fateful combination of a heavy storm, high tide and low pressure creates a once-in-a-century surge of sea water that batters the coastal defenses of the Netherlands, a country with almost one fifth of its territory below mean sea level, and almost half of it less than one meter above it. At the time of the flood, none of the local radio stations provided evening broadcasts, and most weather stations only operated in the daytime. By the time the scale of the impending disaster became clear to the government's Royal Netherlands Meteorological Institute, it was already too late. Their desperate warning to flee and seek high ground never reached the people in the flood-threatened area in time, and the lower part of the Netherlands, in particular the ironically named province of Zeeland ("sea land") was inundated. A wall of water up to 5 meters high breached age-old dikes and sea walls, rushing inland and killing over 1,800 people in a single night. Realizing that such disastrous events were infrequent, but not impossible, the Netherlands developed one of the largest civil engineering projects of its time: the Delta Works, an extensive system of dams, dikes and storm surge barriers designed to keep the low countries safe from future floods. Only twenty days after the flood, the Delta commission was inaugurated; a formal government body that drew up a plan that took over forty years to complete. Although safety was the number one priority, there were significant other factors. The economically vital port of Rotterdam had to remain accessible. The estuary of the Rhine, Europe's largest river, which right cuts through the affected area, could not simply be blocked off. Consequently, an ingenious system of barriers, movable sluice gates and storm barriers that would only close in times of emergencies was devised. The building of the 'Delta Works' was such an enormous project, that it was sometimes referred to as the 'eighth wonder of the world' - and not without good reason.
Antibiotic resistant bacteria discovered in isolated New Mexico cave April 17, 2012 Research into the growing emergence of drug-resistant bacteria could be greatly assisted by the discovery of bacteria from deep within Lechuguilla Cave in New Mexico. The previously unknown strains of bacteria, which have never before been exposed to humans, were found to possess a naturally occurring resistance to multiple types of antibiotics that doctors currently use to treat patients. This means that these forms of bacteria may have been exposed to naturally occurring antibiotics which, in turn could be used against currently untreatable infections. Scientists from McMaster University and the University of Akron discovered the bacteria in deep recesses of a cave that has until recently been isolated from human contact. It was found that none of the bacteria can cause diseases in humans and have never been exposed to human sources of antibiotics. But remarkably, all of the cave bacteria are resistant to at least one known antibiotic, and some have been found to be resistant to at least 14 different antibiotics. The previously unknown bacteria seem to have built up a resistance to the natural antibiotics present in this isolated environment over a period of possibly millions of years. The pristine Lechuguilla Cave, located in the Carlsbad Caverns National Park, has had restricted access, limited to scientific researchers since its discovery in 1986. It is 1,604 feet (489 m) deep and surrounded by impermeable rock, meaning it can take up to 10,000 years for water to reach its deepest depths. In this environment, free from the influence of human derived antibiotics, the bacteria have developed defenses that have surprised researchers. "Our study shows that antibiotic resistance is hard-wired into bacteria. It could be billions of years old, but we have only been trying to understand it for the last 70 years," says Gerry Wright, scientific director of the Michael G. DeGroote Institute for Infectious Disease Research. "This has important clinical implications. It suggests that there are far more antibiotics in the environment that could be found and used to treat currently untreatable infections." Resistance to antibiotics is a growing worldwide concern, with much of the resistance attributed to the over-use of antibiotics in humans and animals, and heavy use in agriculture. Antibacterial-resistant strains, or "superbugs," now contribute to a number of diseases that were traditionally well-controlled. The implications of this discovery could mean that a new breed of antibiotics could emerge to fight off an increasing number of infections. Source: McMaster UniversityShare - Around The Home - Digital Cameras - Good Thinking - Health and Wellbeing - Holiday Destinations - Home Entertainment - Inventors and Remarkable People - Mobile Technology - Urban Transport - Wearable Electronics - 2014 Action Camera Comparison Guide - 2014 Smartwatch Comparison Guide - 2014 Windows 2-in-1 Comparison Guide - 2014 Smartphone Comparison Guide - 2014 Full Frame DSLR Comparison Guide - 2014 Tablet Comparison Guide - 2014 Superzoom Camera Comparison Guide - 2014 iPad Comparison Guide - 2014 Entry-Level to Enthusiast DSLR Comparison Guide - 2014 Small Compact Camera Comparison Guide
China has a tradition of poetic education, and Chant Verse is a significant historical link sustaining Chinese ritual civilization. Reciting the Book of Songs and Historical Records with intonation and expression is the obligation of musical officers in the Chun Guan, which is one of the articles of Zhou Li. Much more can be said about the social formation and function of Chant Verse in the Zhou Dynasty based on its official position, like identifying and tracing the obligation and studying the cultural function of musical officers, who are usually blind. Meanwhile, the comparisons between the great masters of Six Teaching Poetry and the musical officers, who educate people in musical language, can also be made and analyzed. This research will contribute to our understanding of Chant Verse: its source, its early cultural origin, its social patterns, and its historical value.
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Teacher Resources by Grade \|1st - 2nd\|\|3rd - 4th\| \|5th - 6th\|\|7th - 8th\| \|9th - 10th\|\|11th - 12th\| Become a Character: Adjectives, Character Traits, and Perspective \|Grades\|\|9 – 12\| \|Lesson Plan Type\|\|Standard Lesson\| \|Estimated Time\|\|Two 45-minute sessions\| - review the characteristics of adjectives. - define the literary term "character trait" and explore how to provide details that support their inferences. - conduct research using Internet reference resources to find accurate and descriptive word choice. - explore perspective by writing descriptive word lists from the point of view of a character in a novel they've read recently. - Review the adjective part of speech, using the Capital Community College "Guide to Grammar and Writing" Website or your grammar textbook as as reference. - Brainstorm a list of character traits or provide a short list on the board, to provide a sample for students. - Working from the information on adjectives and the sample character traits, compose a class definition of the literary term. - Using a character from another work that students have read, demonstrate the process of compiling a list of character traits, using online resources such as an Internet dictionary or thesaurus or the thesaurus in Microsoft Word. Share the list of character traits with students, if desired. - Compile the data for the character in the Character Traits Interactive Chart, showing students how to add items to the chart as well as how to print and save their work: - Type your name in the first slot in the interactive. - For the title, choose the character name. Students may also indicate the book which includes the character. - Click Next to move to the chart screen and enter your information. - In the first column, write the character's actions from the book. You can include page numbers also. In the second column, write the character traits related to the action. - Demonstrate that writing is not limited to the size of the box shown on screen. Answers will scroll. - When you’ve finished writing your responses, click Finish at the top of the screen. - In the next window, click Print. Your answers will be displayed in a Web browser window. - To print answers, choose the Print command from the File menu. To save your answers, choose the Save As... command from the File menu. Students can open the file later in a Web editor or a word processor that imports HTML (such as Microsoft Word or AppleWorks). - Show students that the instructions for using the tool are available by clicking Instructions at the top of the screen. - Type your name in the first slot in the interactive. - Divide students into pairs or small groups. Have students work through the character traits on their own for one character from the book they're reading, using the Character Traits Interactive Chart. Ideally, the character that they focus on will be the same character whose point of view they will adopt in Session Two. If computers are not available, students can use the Identifying Character Traits Worksheet. - Once students have compiled a list of traits and support from the novel, give each pair or group a piece of butcher paper or newsprint and a wide marker. - Use the Become a Character assignment as an overhead or handout to explain the activity to the class. - Give the students the remainder of the class to work on their lists. - Give students 10–15 minutes to finish their lists and their charts. - As students finish, post their work on the wall or board until all the lists are up. - Number the papers and assign each list a letter, so that everyone can refer to a particular list easily. - Each student pair then examine the posted lists and, on a sheet of paper, attempts to identify who is being described. - Depending upon the time available, look at each list or a selected number of lists, discussing identities. - The authors of the lists under discussion finally give the "right answers." Again, depending upon time, the class can discuss the adjectives in each list and can cite specific events and details from the text which either support or call into question the accuracy of those adjectives. - (Optional) Have students look for patterns such as the number of pairs who chose a particular character, or adjectives that were repeated by several groups, as well as adjectives that did the best job of description. Work Characters The Hobbit Bilbo, Gandalf, Smaug, Thorin To Kill a Mockingbird Scout, Jem, Atticus, Boo Romeo and Juliet Romeo, Juliet, the Nurse, Mercutio The Color Purple Celie, Nettie, Mister, Shug Adventures of Huckleberry Finn Huck, Tom, Jim, the River Ender's Game Ender, Peter, Valentine, Bean The Great Gatsby Gatsby, Daisy, Nick, George Wilson Death of a Salesman Willy, Biff, Bernard, Uncle Ben The House on Mango Street Esperanza, Mama, Papa, Alicia This lesson plan could also be used as a semester review. Each group could focus on characters from different readings. In addition to identifying the characters, students would identify the work that the characters are in. - Expand on students' focus on a particular character from the novel by having them write a character diary entry from their adopted character's point of view. Use a diary prompt from Traci's Lists of Ten, or let students make up their own topics. - Have students use the Profile Publisher either as an aid in generating their list of adjectives before the Become a Character Assignment or as a synthesis of their learning at the completion of the lesson. Informal assessment works best for this activity. As students work on their list, circulate among pairs, observing students' use of reference books and their lists of adjectives. Provide support and feedback as you move from group to group. The ultimate assessment for this activity will be students' reaction to the lists written by their peers and their ability to provide support for the traits on the list. As students go over the lists as a group, reinforce good choice of traits, noting both students' word choice and the connection between trait and character.
Program Arcade GamesWith Python And Pygame What makes a computer language? Why do computers have them? Why are there so many different computer languages? It isn't necessary to understand the answer to these questions to do basic programming, just like understanding how an engine works isn't necessary to drive a car. However to progress to an advanced level it is. This chapter provides a brief explanation to get started with. Computers are electronic, and they are digital. To a computer everything is in terms of no voltage potential along a wire, or some voltage available. No voltage means a zero to the computer, and some voltage means a one. Computers can't actually count higher than that without combining multiple ones and zeros. In the early days, switches were used to load ones or zeros into computer memory. Figure 2.1, courtesy of Wikimedia Commons, shows an Altair 8800. The front panel switches were used to load in the program. The lights showed the output. There was no monitor. Each set of on/off switches represented a number. Each number would represent data or an instruction for the computer to perform. This system of only using ones and zeros to represent numbers is called the binary number system. This type of computer language is called a 1GL (First Generation Language). Note: There isn't a language called 1GL, it is just an abbreviation for First Generation Language. 1GL is the same thing as the machine's native language (machine language) where numbers represent the commands and data for the program. Binary numbers are usually represented in groups of four. For example: 1010 0010 0011 Both data and computer instructions are stored in binary. Machine language are the binary numbers representing instructions that the computer interprets. Not all binary data is machine language however. Data such as documents, databases, financial figures are also stored in binary on the computer. This data is, of course, not intended to be run by the computer. An improvement over entering programs via switches was the use of hexadecimal codes. The decimal numbers used by most people use the digits 0-9. Hexadecimal uses the numbers 0-9 and A-F to represent a set of four switches, or the numbers 0-15. See the table below for an idea of how binary, decimal, and hexidecimal relate. In order to make entering programs easier, later computers allowed users to enter programs using assembly language. Each command used a mnemonic, and a program called a compiler would change the mnemonics into the numbers that represented the commands. Assembly Language is also called a 2GL language, or Second Generation Language. While this was an improvement, it still wasn't very easy to program. The next generation of languages allowed for higher-level abstractions. The first of the third generation languages (COBOL, FORTRAN and LISP) were a lot easier to understand and program. The second and third generation languages used a program called a compiler. A compiler takes the program typed in by the user (called source code) and turns it into machine code. The programmer then runs the machine code. The original source code is not run. If there are several pieces of source code in a program, they can be linked together into one program with the use of a program called a linker. The linker is run on the machine code generated by the compiler to generate a final program. This final program is what the user runs, and the original source code is not needed. A disadvantage of compiling to machine language is that the program only works for that particular type of machine. Programs compiled for Windows computers do not work on Apple Macintosh computers, or Linux computers. Because the whole compile and link steps could be complex for new programmers, some languages instead ran using interpreters. These programs look at the source code and interpret it to machine language instructions on the fly. It also allows the same programs to run on Windows, Mac, and Unix computers, provided there is an interpreter available for each platform. The drawback of using interpreters is that it is slower to operate through an interpreter than in the machine's native language. Python is an example of an interpreted language. It is easier to develop in Python than C, but Python runs slower and must have a Python interpreter to work. Languages such as Java use a system where programs are compiled to machine code that runs on a Java Virtual Machine (JVM), rather than the actual machine. Another popular language that does this is C#, a Common Language Infrastructure (CLI) language that runs on the Virtual Execution System (VES) virtual machine. A full discussion of these is beyond the scope of this book, but feel free to read up on them. There are many different computer languages today. Because computers perform so many types of tasks, different languages have been developed that specialize in these tasks. Languages such as C are good for operating systems and small embedded computers. Other languages like PHP specialize in creating web pages. Python is a general purpose language that specializes in being easy-to-use. The company Tiobe keeps track of the popularity of various programming language in their index that is updated each month. It is a good idea to look here, and at job placement boards like DICE to keep up to date with what languages employers are looking for. Thankfully almost all languages share the same common elements, and once one language has been learned, the same theories will apply to the other languages. For an entertaining history of computing, I recommend watching: Triumph of the Nerds by Robert X Cringley, a three part series on the origins of computing. The movies are entertaining enough that your entire family might enjoy them. I also recommend the book Accidental Empires if you are more into reading than video. What happens after those videos? They don't even cover the birth of the Internet! Then check out the video series Nerds 2.0.1 also by Robert X Cringely. You are not logged in. Log in here and track your progress. English version by Paul Vincent Craven Spanish version by Antonio Rodríguez Verdugo Russian version by Vladimir Slav Turkish version by Güray Yildirim Portuguese version by Armando Marques Sobrinho and Tati Carvalho Dutch version by Frank Waegeman Hungarian version by Nagy Attila Finnish version by Jouko Järvenpää French version by Franco Rossi Korean version by Kim Zeung-Il Chinese version by Kai Lin
Farming was invented independently by ancient humans at least nine times in different regions throughout the globe. The invention of farming is linked by experts to the evolution of early social complexity. Here is a visualization of the original ancient centers of agriculture production: Millions of years before the first humans began farming, ants had already mastered their own version. Leafcutter ants use leaves to farm fungus that they then consume. In many ways, the processes of leafcutter ants resemble human farming. While several types of ants farm fungus, leafcutter ants have some of the most complex societies in nature, with colonies of millions of ants. The farming of fungus allowed leafcutter ants to evolve and maintain huge, complex populations—an interesting analogy for the evolution of human civilization. Modern diversified human agriculture does not resemble the one-crop subsistence version practiced by ants. However, some researchers believe that the effects of ant agriculture on colony size and complexity could be used to better understand these same dynamics in humans. Seshat editor, Lawrence University professor, and Santa Fe Institute researcher Dr. Peter Peregrine founded the group Convergent Evolution of Agriculture in Insects and Humans in 2014. The academic organization studies the evolution, practices, and social effects of farming. Dr. Peregrine’s work was recently featured on science website Phys.org. “If you can hit upon an adaptation that’s a really good one, like agriculture, then you’re apparently tremendously successful [as a species],” Dr. Peregrine told the website. Early agricultural areas like China’s Middle Yellow River Valley and the Fertile Crescent in modern-day Iraq soon became the largest, most complex societies in the ancient world. Dr. Peregrine hopes that studying ant agriculture will lead to important insights on how to improve our farming methods and technology. Coe, Michael; Koontz, Rex. 2013. Mexico: From the Olemcs to the Aztecs. Thames & Hudson. Seshat: Global History Databank, 2016. Retrieved May 11, 2016.
The Nuu-chah-nulth are a group of related American Indian tribes of the Pacific Northwest region of North America. They live on what is now the southwest coast of Vancouver Island, Canada, and on Cape Flattery—the northwest tip of the U.S. state of Washington. The Native American groups on the cape make up a branch called the Makah. The name Nuu-chah-nulth means “all along the mountains,” referring to the mountains of Vancouver Island. The Nuu-chah-nulth people are also called the Nootka. The Nuu-chah-nulth are Northwest Coast Indians who traditionally spoke a Wakashan language. They are culturally related to the Kwakiutl, another member of the Wakashan language family. The Nuu-chah-nulth built rectangular, multifamily houses using cedar posts and planks. Central and southern Nuu-chah-nulth groups lived in villages that were independent of one another. Groups to the north usually formed larger tribes with large winter villages. There were also several confederacies of tribes that shared summer villages and fishing and hunting grounds near the Pacific coast. The Nuu-chah-nulth moved with the seasons to be near the best food sources. They obtained much of their food by fishing and hunting sea mammals, including whales, seals, and sea otters. The whale hunt was a prestigious event; the harpooner was a person of high social rank, and families passed down the magical and practical secrets that made for successful hunting. The Nuu-chah-nulth also hunted land animals such as deer, elk, bears, and beavers and gathered wild plant foods such as roots, berries, and bulbs. In winter they ate dried fish, especially salmon. The first European to encounter the Nuu-chah-nulth was Juan Pérez, a Spanish explorer who reached the west coast of Vancouver Island in 1774. He was followed by the Englishman Captain James Cook, who spent a month among the Nuu-chah-nulth in 1778. The Nuu-chah-nulth provided sea otter furs to Cook in exchange for goods such as metal tools and guns. The fur trade expanded in the 1780s with the arrival of English, Russian, Canadian, and American traders. Nuu-chah-nulth groups competed for control of the fur trade, sometimes attacking each other with their newly acquired guns. This warfare, combined with diseases introduced by the Europeans, greatly reduced the number of Nuu-chah-nulth. By the early 1800s hunting had nearly wiped out the sea otter population, leaving the Nuu-chah-nulth with nothing to trade. Some Nuu-chah-nulth began attacking European trading ships, causing whites to avoid Vancouver Island for decades. In the second half of he 1800s the Nuu-chah-nulth reestablished trade with whites, offering furs of other animals (including deer, elk, and seals) as well as dogfish oil and handicrafts. Many tribal members found work in the commercial fishing and sealing industries. In the late 1800s the Canadian government set aside small reserves for the Nuu-chah-nulth on Vancouver Island. Many tribal members still live on these reserves. In the early 21st century there were more than 9,200 people of Nuu-chah-nulth descent in Canada.
ARPA launched the first satellite in what would become the world's first global satellite navigation system. Known as Transit, the system provided accurate, all-weather navigation to both military and commercial vessels, including most importantly the U.S. Navy’s ballistic missile submarine force. Transit, whose concept and technology were developed by Johns Hopkins University Applied Physics Laboratory, established the basis for wide acceptance of satellite navigation systems. The system's surveying capabilities—generally accurate to tens of meters—contributed to improving the accuracy of maps of the Earth's land areas by nearly two orders of magnitude. ARPA funded the Transit program in 1958, launched its first satellite in 1960, and transitioned the technology to the Navy in the mid-1960s. By 1968, a fully operational constellation of 36 satellites was in place. Transit operated for 28 years until 1996, when the Defense Department replaced it with the current Global Positioning System (GPS).
21 August, 2007 Matching leads to understanding the concept of one-to-one correspondence. When a child passes out cookies, each child in the room gets one cookie. Maybe there are just the right amount of cookies or maybe there are extra cookies. When counting blocks, each block is counted once and only once. Matching forms the basis for our number system. When a child can create “the same”, it then becomes possible to match two sets. This becomes a prerequisite skill for the more difficult tasks of conservation.Matching occurs in many everyday activities: - Getting dressed, eating, school, playing, and other activities: setting the table, folding the laundry (match socks and clothes to child, mom, dad), sharing birthday treats. The following are different ways that children can practice matching skills. Number Concept Dot Match and Sort Sets are available to support conceptual development. (Use the Match and Sort Number Concept Dots or other like materials) 1. Matching items that are different (Visually easier to match items that are different). • Use the Number Concept Dot Match and Sort Set or similar items. Place 4 paper plates in front of the child. Give the child 4 circles. Have the child use the circles and match a circle to each of the plates. Extend: Give the child more plates and/or different shapes. 2. Matching items that are the same (More difficult to determine if each item has a mate) • Use the Number Concept Dot Match and Sort Set or similar items. Use 2 red circles, 2 red squares, 2 red triangles, and 2 red rectangles. Lay out one of each. Give the child the remaining red shapes. Ask the child to match each shape with one that is the same. This has the child looking for “sameness” of shape. Extend: Give the child all of the squares and ask them to make color matches. 3. Match a few items (1 – 5) Match many items (easier to match in the 1-5 range) • Use the Number Concept Dot Match and Sort Set or similar items. Begin with 1 to 5 shapes in two colors. Place all of the shapes in one pile. Ask the child to find two shapes that are the same. Continue until all shapes are matched. Extend: Increase the number of shapes and/or the colors that are given to the child. • Place 3 shapes in one row. Place 5 shapes in a second row (3 of the same shapes). Ask the child to match. Watch to see what the child does with the extras. Extend: Increase the number of shapes in rows one and two. 4. Match items that have the same number in each set • Use the Number Concept Dot Match and Sort Set or similar items. Make a set that has three different shapes. Make a second set that has the three shapes and three other shapes. Ask the child to build a matching set. In this task, the child is matching sameness of number. Extend: You can increase the number of shapes in both sets. • Place 4 different colored circles on a paper plate, Give the child a paper plate and one colored circle. Ask the child to make a match on his/her plate. Extend: Change the shapes that you place on the plate. It becomes more difficult when you ask the child to look for color and shape matches. 5. Match items that do not have the same number in each set/row • Use the Number Concept Match and Sort Set. Lay out any color circle, triangle, square, and rectangle in a line. Give the child three of the four shapes and ask them to match each. Watch to see what the child does when he/she cannot find a match for one of the shapes. Ask questions to help the child see that sometimes all items do not match.
Biotic Factors Definition and Examples The biotic factors are all living organisms, which interact with other living organisms. On the other hand, the relationships between the organisms of an ecosystem are also called biotic factors. These relationships condition the existence of all the inhabitants of the ecosystem, since they modify their behavior, their way of feeding and reproducing, and in general the necessary conditions to survive. Relationships of dependence and competition are among these relationships. That is to say that biotic factors are living beings, but always considered in a network of relationships between flora and fauna. In the ecosystem there are also abiotic factors, which are those that also condition the existence of living beings, but that are not living beings, such as water, heat, light, etc. Biotic factors are classified as: Individual factor: An organism individually. That is, a particular horse, a particular bacterium, a particular tree. When studying changes in an ecosystem, it is important to determine if a single individual of a species can cause significant changes or not. Population biotic factor: They are the set of individuals that inhabit the same area and are of the same species. Population biotic factors always modify the ecosystem in which they are integrated. Biotic factor community: They are a set of different biotic populations that coexist in the same area. The concept of community biotic factor allows to observe the relationships between the populations but also as the community as a whole is related to other populations that do not belong to the community. Examples of biotic factors Producers are those organisms that produce their own food. They are also called autotrophs. Consuming organisms are those that can not produce their own food. Here we include herbivores, carnivores and omnivores. Decomposers feed on organic matter, decomposing it into its basic elements. Mosquito larvae (insect)
Cigarettes as radioactive as x-rays Peering through the propaganda smokescreen, Dr Karl finds out why smoking cigarettes can be as radioactive as a daily x-ray. When I was a medical doctor in the hospital system, every now and then I needed to get a chest x-ray on a patient who was also a cigarette smoker. Quite often, they would get nervous about the potential radiation damage from a chest x-ray. But when I told them that two packets of cigarettes gave them the same radiation dose as a chest x-ray, they would not believe me. This raises two questions. First, how did a radioactive metal get into their cigarettes? And second, why did they not believe me? Every year, we humans smoke about six trillion cigarettes, enough to make a chain that would easily reach from the Earth to the Sun, and back, and then do the whole trip again, just for good measure. By 2020, cigarettes will be killing about 10 million people each year. They have already knocked off 100 million people in the 20th century, and if we don't come to our senses, they could kill one billion in the 21st century. The radioactive metal in cigarettes is polonium-210. It was discovered in 1898 by Marie and Pierre Curie. It is extremely toxic (about 250-million-times more toxic than cyanide) and is naturally present in uranium. Developed countries use fertiliser that is manufactured from apatite rock, and this rock naturally contains uranium which then decays to radioactive polonium-210, which enters the tobacco plant through both the leaves and roots. When the cigarette burns, it reaches temperatures of 600–800°C, hotter than the melting point of polonium. The liquefied polonium sticks to tiny particles in the cigarette smoke, and then preferentially lands at locations in your airways and lungs, where one pipe splits into two pipes. Polonium-210 has a very short half-life of 138 days. It is intensely radioactive, and sprays alpha particles on to the surrounding tissues. Now, most people would be definitely worried if you suggested that they have a chest x-ray every day for the rest of their lives. But some of these people quite happily smoke, sometimes up to two packets of cigarettes every day. Cigarette smoke is already loaded with various chemicals that are well-known to cause cancer. It's estimated that the radiation dose from the polonium-210 in cigarettes accounts for about two per cent of cigarette deaths. That is several thousand deaths each year in the USA alone. It was first discovered that cigarettes contained radioactive polonium about half a century ago. So how come it's not general knowledge? The answer is simple. Big Tobacco has done an excellent cover-up job for the last half century. Once they realised that there was radioactive polonium in tobacco, they started their own internal — and very secret — research program. They even came up with ways to drastically reduce the amount of polonium in cigarette smoke. At one giant tobacco company, RJ Reynolds, a memo was sent, and it read, referring to the radioactive polonium, "removal of these materials would have no commercial advantage". But there was another reason why they wanted to keep their research secret. At the Phillip Morris tobacco company in 1978, a scientist, Paul Eichorn, wrote a memo to his boss, Robert Seligman, the then vice-president of research and development at Philip Morris. Eichorn wrote, referring to research on polonium, "it has the potential of waking and sleeping giant. The subject is rumbling, and I doubt we should provide facts." But the big tobacco companies had yet another reason for not publishing their research. They were following their infamous motto of 'doubt is our product'. So any tiny variation in the research done by scientists outside the tobacco industry was spun into the spurious claim that even the experts don't really know what makes smoking harmful. Big Tobacco's internal research showed that polonium was harmful, but to quote an internal Philip Morris document from 1982, so long as they kept their research quiet, any suggestion of a link between polonium-210 and lung cancers is "spurious and unsubstantiated". Perhaps Big Tobacco should get some of their own internal research x-rayed, so they can see through their own smoke screen. Published 13 March 2012 © 2016 Karl S. Kruszelnicki Pty Ltd
Alzheimer’s Disease (AD) is a form of dementia which causes memory loss and can inhibit intellectual abilities severely enough to interfere with a person’s daily activities. Billions of nerve cells connect to one another in our brains transferring tons of information like a giant communication network. In a patient with Alzheimer’s disease, the communication is interrupted. Parts of the brain involved with specific tasks such as thinking, learning, and memory become uncoordinated, tampering with cognitive abilities. AD is known as a progressive disease, meaning the damage worsens and/or spreads over periods of time. The rate of progression, however, is unique to each patient and the symptoms vary greatly depending in part on age and other health conditions that may reside. To perform at its greatest potential, our brains require coordination. With each group of cells in control of a certain bodily function, they act like tiny factories, carrying out each task in a routine manner. In a patient with AD, this signal flow is interrupted by progressive damage. Scientists believe that Alzheimer’s Disease prevents parts of the dense-branching communication network from running smoothly. The damage ultimately spreads to other parts of the brain causing irreversible damage and leading to the various symptoms associated with AD. Each case of Alzheimer’s is unique to the patient and the symptoms experienced are of a broad array. Effects of the disease can range from slowed thinking and memory loss to difficulty swallowing, speaking and walking. In the early stages of an AD diagnosis, the area generally affected responds to learning and memory. Early symptoms include difficulty remembering new information, memory loss, and slight mood and behavioral changes. In a patient with moderate AD, organizational skills, understanding speech, expressing oneself, and planning are impaired. Progressively the disease can affect thinking, sense of time and place, and minor interferences within work and social life can be noticed. In the late stages of AD, the brain is severely damaged and the symptoms are very difficult to treat. The cortex and hippocampus of the brain shrink dramatically and fluid-filled spaces within the brain, called ventricles, begin to enlarge. Inability to recognize family, perform daily tasks, communicate, walk, and swallow are some of the symptoms generally experienced in the late stages of an Alzheimer’s Disease diagnosis. Treatments today for Alzheimer’s include medications for many of the symptoms such as prescription drugs for behavioral changes, sleep patterns, and pain management. Some medications work by assisting in the performance of chemicals in the brain responsible for the transfer information from one cell to another. Many herbal remedies and supplements are also available for use to help relieve symptoms experienced. These methods temporarily improve the symptoms of memory loss and problems with learning and reasoning. While relief can be found in the symptoms associated with AD, no cure exists for the chronic disease. Stem Cell Therapy for Alzheimer’s Disease In explaining how stem cell therapy can be beneficial to a patient with AD it is important to understand what exactly happens in the brain when battling this condition. In a patient with AD, protein deposits, called plaques, build up in the spaces between nerve cells far more rapidly than normally associated with aging. Tangles, twisted fibers that build up inside dead and dying nerve cells, also produce at a faster rate. These two occurrences tend to follow a pattern, targeting areas most critical for memory then progressively spreading to other regions. The damaged nerve cells are then unable to properly transmit electrical signals within our brain, those signals that are responsible for memories and individual thoughts. Stem cells reproduce at a rapid rate and have the potential to be many different cell types in the body. Stem cell therapy for Alzheimer’s disease is a breakthrough procedure in regenerative medicine and Stemedix uses adipose (fat) or umbilical cord derived stem cells as methods of therapy for you in your journey to wellness. These regenerative therapies help the body’s natural healing process work faster and more effectively. These procedures are designed to aid in the restoration of dying tissues in the body. In the treatment of AD, the stem cells are collected, enriched, and administered in hopes of replacing the dying nerve cells in the brain. These advancements in the treatment of AD work to potentially regenerate missing or damaged tissue that the body would not ordinarily regrow. Recent research of AD and related dementias brings upon new treatments for those battling it. Past treatments have shown that stem cells not only have the potential to regenerate the lost or damaged tissues in the brain, but also have the ability to temporarily modulate the immune system, disabling the abnormal attack. By addressing these two areas of AD, potential improvements with the following symptoms have been observed: - Enhanced behavior and mood - Reduction or elimination of confusion - Improvements in motor skills - Improved cognitive function - Reduction of memory loss - Increased energy While aging is among the greatest risk factors for AD, it does not have to be a normal part of the aging process. With our stem cell therapy for Alzheimer’s disease, hope can be returned to those attempting to manage their condition. When traditional medications show less than optimal results, advanced technology offers a natural procedure to assist your body in rebuilding itself. tem cells treatments offer a new way of approaching AD that not only addresses the abnormal immune response, but also aids in the restoration of diseased and dying nerve tissues of the brain. There is no cure for Alzheimer’s Disease, but these methods have potential benefits in the management of symptoms. Contact us today and let Stemedix provide a worry-free experience accompanied by one of our Care Coordinators to ensure you have the best experience possible.
We’ve thus far talked only of silicon, but we’re now ready to introduce another element into our studies; Phosphorus. Phosphorus is right beside Silicon on the periodic table, element number 15. As such, it has 15 protons, and 15 electrons, the key difference being that Phosphorus has 5 valence electrons (where Silicon had only 4). Suppose we took our Silicon crystal lattice, plucked out one of the Silicon atoms, and replaced it with a Phosphorus atom. We’d end up with something that looks as follows. http://media.hardwareanalysis.com/articles/small/10653.gif" alt="Semiconductor Physics">Fig. 7 - A silicon lattice with a single impurity atom added. The Phosphorus impurity has one extra valence electron which, after all bonds are made, is free to roam about the material and aid in conduction, even without any form of carrier generation, such as the application of heat or light. It will always exist because it cannot recombine; there is no corresponding hole for it to fall back into. The Phosphorus atom assumes the place of a Silicon atom, and makes four bonds, one with each of its neighbors. Like the Silicon it replaced, the Phosphorus must give one of its valence electrons to each of the four bonds. The difference is that Phosphorus has five valence electrons, so after making all four bonds, it still has one left over. This remaining electron is not trapped in any bond, and is thus free to roam about the material in the Conduction Band, and participate in conduction. By implanting more Phosphorus atoms, we can create a small army of free electrons that will always be in the Conduction Band, and always available to participate in electrical conduction. Further, because the free electron did not come from excitation, it was not accompanied by the creation of a hole (it did not break out of a bond; it was never in one). As a result, the sample now has one more free electron than it does holes. This is called an Extrinsic material (a material with more of one type of charge carrier than the other). Each Phosphorus atom added into the sample produces another free electron without generating a corresponding hole, thus making the material more and more extrinsic. To reinforce the usefulness of this type of doping, consider the following figures: intrinsic silicon at room temperature has on the order of 1010 charge carriers per cubic centimeter available at all times, simply due to thermal generation. Using common modern technology, we can easily implant in excess of 1017 Phosphorus atoms per cubic centimeter, thereby increasing the number of charge carriers from 1010 , an increase of 10,000,000 times. Clearly, this will very drastically impact the conductivity of the sample.
Global warming is not the only huge problem facing humans on planet earth. It is no news that the environment is becoming polluted due to our greed and indifference. Oceans are now the biggest single garbage dump on this planet. Our grandchildren are going to drown in waste, literally, unless we do something. We will survive only after we realize that waste can be turned to money and recycling can be profitable. Objects around us are not disposable but reusable raw material. There are, however, ways to efficient recycling leading to more sustainable production and consumption. We are fortunate to have the needed technology to turn the course of events and solve many of the key problems in the current industry: material identification, contaminants, and final purity. Recycling in numbers Are we exploiting maximum recycling potential and are all materials that are recyclable, actually being recycled? It is true that the amount of plastic, glass, paper, and metal recycled from waste has been steadily rising over the years. This is a big positive change. Yet many countries are still far from reaching their recycling targets. According to statistics, collected waste percentages in some European countries are surprisingly high, far above 80%. Germany gives “recycling” rates of 67% for household waste, around 70% for production and commercial waste, and almost 90% for construction and demolition waste. But a closer look to statistics shows that a large portion of the waste is actually used for energy production and burnt in power plants. As an example, in EU over 27% of all municipal waste was incinerated in 2016. This means that waste is not really recycled, and we still need virgin materials like wood and oil to produce new consumables. This matters since the main benefits of recycling are to conserve natural resources like fossil fuels, save in energy and reduce greenhouse gases and pollution. It is calculated that recycling reduces energy consumption by about 70% for plastics, 60% for steel, 40% for paper and 30% for glass. These are high numbers knowing the amount of annual production. Problems in waste treatment In most cases, available sorting technology limits the amount of material that can be recycled. Typical waste recycling process includes collection to the recovery facility, separation to different waste streams, basic cleaning and final sorting to classes. The resulting product is then either burned, recycled based on type and purity or placed to landfill. At the moment these recovery or recycling plants use different technologies from barcode readers, RGB cameras to x-ray and eddy current systems. These are capable technologies to some extent but not perfect solutions as they cannot recognize the material itself. For example, in case a plastic bottle is missing its label with printed barcode it is not possible to say if it is PET or HDPE. So-called multispectral technology is helping but is limited to a few basic materials in each sorting location. It is also a fact that human labor must be used due to inadequate detection technologies. Waste is shipped to lower cost countries where people are manually sorting materials from conveyor belts. Although this creates jobs, it is by far not the safest and most desirable of professions. It would be beneficial to have robots or other sorting machinery in most places – but a robot needs “visual” aid for material detection. Spectral camera – state of the art solution Spectroscopy is the art of measuring the interaction between light and matter. In all matter around us this interaction, absorption, and reflection, is different. All different plastic types, wood, paper etc. have different spectra that we can measure using a spectrometer. As an analogy to visual interpretation, we can say that materials have different “colors” in the infrared region of light. This makes sorting based on actual material type possible just by measuring their spectrum. A spectroscopy instrument is called spectral if it is capable of aerial imaging. The camera is placed above a conveyor belt and, while the material is passing by, it gives information on the exact material type, position in belt and size. Information is then passed to the sorter for proper action. When used together with other technologies, spectral cameras make sorting more accurate as they provide true information on material type. The latest generation of hyperspectral cameras can increase the purity of recycled materials to close to 100%. This is important since the possibility to recycle plastic polymer for example generally depends on the material purity. Increasing the purity of recycled material by even a few percents can double its value. Extracting more recyclable material also means that we are disposing less waste to landfill. Very recent advances in spectral camera technology further to infrared spectrum has made it possible to develop a camera that is also capable of separating black plastics, which has been a huge, unsolved problem hindering recycling efficiency for many years. Recycling and sorting systems will continue to evolve and become more accurate and easier to implement. At the same time, these systems become completely automated and use different sensors and robotics. One thing is certain: the spectral camera is one key element for improving recycling success. Esko Herrala – Co-Founder, Senior Application Specialist This article was originally published in LinkedIn.
Seed Sensation: Exploring and Sorting Seeds Students learn all about seeds through dissection, classification, comparison and contrast, and hands-on planting experience. - Grades: PreK–K, 1–2 - Unit Plan: Students will explore seeds through dissecting, sorting, comparing and contrasting. They will discover their location in fruits, vegetables, and in the environment. They will learn the many ways seeds travel and what they need to grow. They will also plant seeds and observe their growth over time. The students will: - Dissect a seed and identify the parts and their functions. - Discover where seeds can be found. - Compare and contrast seeds by size and color. - Learn how seeds travel. - Predict and observe what seeds need to grow. - Magnifying glasses for each student - A dry pinto bean for each student - A soaked pinto bean for each student - Paper plate for each student - Drawing paper - Black pens - Water colors, brushes, and rinse water - Chart paper and markers - Various fruits and vegetables (apples, oranges, strawberries, pepper, corn, guava, avocado) - A large basket - An apple and orange for each pair of students - A sharp knife - Magnifying glasses for each student - Paper plates for each student - Water colors and brushes for each student - Black pens for each student - Cups of rinsing water for each student - White cardstock or art paper for each student - Multiple kinds of seeds-flower and vegetable, nuts in their shell, dry corn, beans, unshelled sunflower - Small twigs - Gravel or tiny rocks - Plastic bags - Paper plates - Magnifying glass for each student - Seed Sorting Sheet (PDF) - Chart paper and markers - Seeds by Ken Robbins, The Tiny Seed by Eric Carle or any book about seeds - Duct tape - A field or grassy area - Magnifying glasses fro each student - Seed Sorting printable from Day 3 - One of each seed (or you may choose others) for each student: corn, sunflower, pinto bean, lima bean, or rye grass - Small paper cup for each student - Large clear plastic cups for each student - Magnifying glasses for each student - 9- by 12-inch black construction paper for each student - Permanent markers - Seed Growth Recording Sheet (PDF) - Teacher sample - Chart paper Set Up and Prepare - Soak the pinto beans in warm water for 24 hours. - Set aside rinse water for paintbrushes. - Gather the basket of fruits and vegetables. - Cut apples and oranges in half for each pair of students. - Set aside the rinse water for paintbrushes. - Create one plastic bag for each student with a mixture of multiple kinds of seeds: flower, nuts, vegetable, beans, and unshelled sunflower. - Gather small twigs. - Gather gravel or tiny rocks (fish tank gravel is good). - Copy the Seed Sorting Sheet (PDF) on cardstock for each student. - Cut a 10-inch piece of duct tape for each student and stick it to a place where you can easily retrieve it. - Make arrangements to visit a grassy area. - Copy the Seed Growth Recording Sheet (PDF) for each student. - Soak seeds in a bowl with 1 teaspoon bleach (so the seeds do not mold) for 5 minutes. - Place one of each seed in a paper cup for each student. - Cut a 12-inch strip of construction paper the width of the clear plastic cup for each student. - Make a teacher sample of the project on Day 5 so there is no growth. Day 1: What's Inside a Seed? Step 1: Distribute a dry pinto bean and magnifying glass to each student. Remind them not to put it in their nose, ears or mouth! Ask the students what they think it is. Some will say a bean; others may say it is a seed. Tell them that it is a bean, which is a kind of seed. Ask: What is the job of a seed? Tell them that today we will discover the job of a seed. We will dissect, or open up, the seeds and look inside. Ask the students to open their seeds (without using their teeth) and describe what they see inside. Step 2: After a few minutes, ask if anyone has opened their seed. Probably no one has been able. Ask the students what they wear when it is cold outside (a coat). Tell the students that a seed has a coat covering it until it is ready to grow. Right now it is asleep, waiting to wake up. It may sleep for a week, a month or even a year until it has the right amount of water and warmth. The seed will need water and the soil must be warm enough for it to grow. Step 3: Distribute the soaked pinto beans to each student. Ask them to compare them to the dry one. Inform the students that these pinto beans have been soaked in warm water to imitate the warm soil. Invite the students to try to open these seeds and observe what is inside using their magnifying glasses. Most will see a new plant growing. If they do not find one, give them another bean. Step 1: Gather the students together and ask what they saw inside the seed. Ask one student to draw what they observed on chart paper. Label the parts of the seed for the students with lines extending from the three parts: seed coat (the outer area), food (inside the bean) and the new plant. Step 2: Invite the students to draw a picture of the inside of their seed, label its parts and paint them. Step 3: Gather the students back together and ask them to tell about the new plant they saw in their seed. Ask the students what they think the new plant will do (grow). Ask: Then what is the job of a seed? (To grow into a plant). Day 2: Where Do We Find Seeds? Step 1: Gather the students in a circle. Remind students about the seeds they looked at the day before. Ask: From where do seeds come? Accept all answers. Show the students the basket of fruits and vegetables. Tell the students that seeds are found in the flowers and fruits of plants. Pass around the fruits and vegetables and ask students to use their senses to explore the fruits and vegetables. Then ask if they can tell you where the seeds are located. Most seeds will be inside, but some (corn and strawberries) are visible on the outside. Step 2: Cut the fruits and vegetables open to reveal the seeds. Pass them around for students to explore with their senses. Step 3: Pair the students and send them to their seats. Distribute paper plates, magnifying glasses, half an apple, and half an orange to each team. Keep the halves together so the teams will get to “open them.” Each student will get their own half piece of fruit to explore. Invite students to look with their magnifying glasses and discover the seeds in the fruit. Ask them to count the seeds they find. Step 4: Distribute paper, pens and watercolors to the students. Ask them to draw the apple and orange half on their paper. Encourage them to write “apple” and “orange” next to their drawings. Invite the students to paint their drawings. Step 1: When the paint has dried (watercolors dry quickly), invite students to glue some of their seeds on their paintings where they were found. Step 2: Gather the students together and ask them to describe what was different about the seeds in the apple and the seeds in the orange. Accept all answers. Possible answers may include the number of seeds, the size and shape. Day 3: Seed Sorting Step 1: Remind the students about the time when they dissected, or opened up, the seed. Remind them about the job of a seed. (To grow into a plant). Tell them today we are going to discover what seeds are and what are not seeds. Step 2: Distribute a plastic bag, paper plate and magnifying glass to each student. Invite the students to sort their objects any way they like: size, kind, color, shape, etc. Remind them to use their magnifying glasses to observe the objects. Ask students why they sorted a particular way. After a few minutes, ask the students to stop. Ask volunteers to explain how they sorted their objects. Step 1: Tell students that now they are going to sort their seeds into two groups: seeds and not seeds. Allow a few minutes for students to resort their objects. Step 2: Gather the students together and distribute a seed, twig, or piece gravel to each student. If two students have the same kind of object, that is fine. Ask: Who thinks they have a seed? Who thinks they do not have a seed? Ask them to separate into the two groups (seeds and no seeds). Assist the students in identifying their object. After a few minutes, have them share and identify their objects. Help them name the objects (e.g., flower seed, corn seed, bean, gravel, etc). Step 3: Send the students back to their seats. Allow them to make any adjustments in their sorting. Distribute the Seed Sorting Sheet (PDF) to each student. Read the headings with them. Ask them to glue a few of the different objects onto their sheet in the appropriate columns — Seeds or NOT Seeds. Invite them to label any of the objects. Some may label them as “seed,” while others may be more specific if they know the name (e.g., pumpkin seed, nut) Step 4: Gather the students together and have them share what they discovered about the objects that were seeds compared to the objects that were not seeds. Discuss how the seeds themselves differ? Day 4: How Do Seeds Get Around? Step 1: On one side of the chart paper, write the heading, “How People Travel.” Ask the students the many ways people travel. Accept all answers and chart. Tell the students that sometimes seeds are not always planted by people on purpose. Explain about all the weeds in your garden or at school that you did not plant, but somehow grew there. Tell them that seeds travel too. On the other side of the chart paper write, “How Seeds Travel.” Ask them how they think seeds travel. Accept all answers and chart. Step 2: Read Seeds, The Tiny Seed, or another book about seeds and how they travel. Refer back to the story and ask the students if they want to add or change anything on their chart. Add information from the book about how seeds travel: wind, water, or animals — by passing through them, sticking to their fur, or buried and forgotten. Step 1: Tell the students that people sometimes help seeds travel when they stick to our shoes or clothing and then fall off later. Place the duct tape roll around the cuff of each student’s pants with the sticky side facing outward. Step 2: Take a walk through a grassy field. Step 3: When finished, return to the classroom and examine with the magnifying glass to see if there are any seeds. You can add any to the Seed Sensation Sorting sheets from Day 3. Day 5: Watch Them Grow Step 1: Ask the students what we need in order to grow. Accept all answers. Ask them what they think seeds need. Distribute the magnifying glasses and paper cups with seeds to each student and ask them to examine them. Invite them to name the seeds. Step 2: Distribute the clear plastic cups and the black construction paper. Ask students to write their name on the cups using a permanent marker. Ask the students to roll up the black construction paper and place in the clear cup so that it fills the jar. Step 3: Have the students fill their cups with water. Step 4: Tell them to wedge their seeds between the black construction paper and the cup, half way down and in a row. Show them your sample. Tell them that you will be placing yours in the cabinet and they will be placing theirs near a window. Remind them of the things a plant needs to grow. Ask them to predict what they think will happen to the seeds by the window and what will happen to the seeds in the cabinet. Record predictions on chart paper. Step 5: Have the students place their projects near a window. Step 1: Each day, have the students check their seeds and draw and label what they observe. You may not want to record each day, but have the students write the day on the Seed Growth Recording Sheet (PDF). Step 2: After a few days, compare the students’ seeds with your sample. Ask the students why is there a difference? Review student predictions on chart paper and discuss outcome. Step 3: Either carefully remove the students’ plants and replant in small clay pots or allow the students to take their plants home to replant with their parents. These could make wonderful Mother’s Day presents. Supporting All Learners Where appropriate, help students to label their pictures with beginning sound letters or words. Those that are able can write words or sentences. Take dictation for those students that need it. Using many different seeds (ask students to bring some), make seed collages. Students can first start with a line drawing that they fill in by gluing seeds or they can glue them abstractly to a piece of cardstock or tag board. Encourage patterns and counting where possible. Ask students to make a seed collection at home. Have them take an empty egg carton and try to find one seed for each pocket. Encourage them to look with their families in fruits and vegetables, in their kitchen cupboards, or around their home using the duct tape method (you may need to fasten tape to their pant leg before they go home). - Seed dissection drawing/painting - Apple and orange half project - Seed Sensation Sorting sheet - Seed collection on duct tape - Seed growing cup and recording sheet - Did the students make observations and record them? - Did they participate in discussions? - What kind of emergent writing is apparent? - Was there enough time for students to be successful? - What would I do differently? Observe how students investigate during these experiments. How are they recording growth? How do they participate in group discussions?
Contact: Science Press Package American Association for the Advancement of Science Hear my nectar: How dish-shaped leaves attract pollinating bats Photo montage of a flowering inflorescence of Marcgravia evenia and an approaching Cuban nectar-feeding bat Monophyllus remani. [Image courtesy of Ralph Mangelsdorff and Ralph Simon] Bats use high pitched sounds to locate food and navigate. Humans generally can't hear these high pitched sounds. When these sounds bounce off of objects, bats are capable of listening to the returning echoes, which gives bats a sense about the distance, movement and size of all objects in their path—this is called "echolocation". A new study in the journal Science shows that the dish-shaped leaves above the flowers of the vine Marcgravia evenia beckon bat pollinators by emitting a strong acoustic echo that halves foraging time. The findings provide some of the first evidence of a flower displaying adaptations to acoustically attract bat pollinators, much the way brightly colored flowers serve to attract pollinating bees and insects. While large megachiropteran bats, such as flying foxes, may be able to discern visual cues, smaller or microchiropteran bats, known for using sonar to locate their insect prey, likely miss these colorful signals. Ralph Simon and colleagues show that these unusual echoes of dish-shaped leaves attract bat pollinators by being louder and covering a broader echo detection range than typical leaves; allowing the leaves to stand out amid the chaotic stream of echoes being reflected back from nearby rustling plants. The researchers trained three nectar-feeding bats to search for a single small feeder — attached to either a typical leaf, a dish shaped leaf, or no leaf. Next, the team measured the amount of time the animals took to find the feeders at different positions, and observed that bats found the feeders with dish-shaped leaves almost twice as fast as those without leaves or with foliage leaves.
Crop growers face tillage challenges as they balance production and conservation in the same fields. Aggressive tillage blackens the soil so it can absorb sunlight for the short growing season. Practices that minimize the impacts of corn root balls, excess stover, and the potential for disease are needed. But conservation practices are also needed to stop soil erosion, store carbon and keep the soil healthy to produce high quality crops and good yields. “In reality, we’re still losing soil,” said Jerry Hatfield, director for the USDA National Laboratory for Agriculture and the Environment. “Even with our conservation tillage systems, we have this problem with very intense storms we’ve been getting in the spring. “We have a lot of runoff before we have a growing crop. Even those things that leave 30 percent residue still have quite a bit of soil wash coming off of them.” The U.S. farmer has adopted extensive reduced tillage systems on about 10-20 percent of tilled acres, Hatfield said, although the Natural Resources Conservation Service figures some level of conservation tillage is used on 50-60 percent of farm land. When comparing 1980 with 2010, Hatfield thinks the U.S. farmer has reduced soil erosion. Soil organic matter is remaining at a steady level, and that’s a result of conservation practices. Improving the soil needs to be a continuing goal for every farmer, though. “We probably haven’t improved as much as we need to in terms of saving our soil,” he said. Adopting reduced tillage and using cover crops are two methods for improving soils. The addition of small grain cover crops would protect the soil in the late fall and early spring. “The protection of the soil in the early spring across the Upper Midwest is more critical than at any other time of the year,” he said. “We continue to have higher intensity storms during our springtime when we have very little crop to take up any water, and a limited amount of protection of the soil surface from the storms.” Cover crops also increase the extraction of carbon from the atmosphere. A cover crop removes carbon, puts it back into the soil, and increases the amount of carbon storage within the soil system. “Because we change the type of rooting systems (small grains) that we use as our cover crop, we change the whole dynamic of the soil biology, because we have different root materials out there, and have a more fibrous root system than if we have just corn or soybeans,” he said. “We are changing a number of things dramatically that are for the positive in terms of improving our soils over time.” Researchers are studying the potential for aerial seeding a cover crop following harvest. Another possibility is planting a living mulch, such as clover, that would remain dormant through the growing season but would grow very early in the spring. For continuous corn, Hatfield would like to see more research conducted on leaving the previous year’s corn stalks and moving the planter over 10-15 inches. “In actuality, where you’re not disturbing the old root mass and leaving that stalk standing up - that traps the snow and prevents the residue from moving over, and can result in significant increases in organic matter,” he said. “That’s a very simple change in terms of a cropping system out there.” A planting configuration change is just one item that farmers might want to explore to improve soil health. To improve yields, soils need high quality biological systems, he said. By managing soil microbial populations, farmers can allow microbes to digest the organic matter in the fields. “The biological glue is what creates the stable aggregates that make the soil more resistive to erosion,” he said. “We need to think about what it means to adopt systems that allow the soil microbial system to be as efficient as possible.” As producers push to grow over 200 bushel per acre corn, they will need high quality and healthy soils to accomplish their goals. Finding ways to maximize the water that is available to dry land corn when it is needed is a significant task for farmers too. “You’re not going to achieve sustainable high yields consistently without allowing that soil to support the plant so it doesn’t lodge, but also supply nutrients and water,” he said. “A lot of our systems - we create the potential yield, but we have a hard time fulfilling that potential, because the plant has limitations.” Optimizing genetics, the suite of protection systems that are added to a plan, and the soil system are all needed to allow the crops to have access to as much nutrients as they can get. As producers look at the second decade of the 21st Century, they may well have to adopt varying management practices to achieve their yield goals across the farmlands. It’s very likely those practices will include a combination of tillage, conservation tillage, no tillage plus cover crops to maintain the very valuable farm soils.
George Rogers Clark Day, February 25 (1779) George Rogers Clark is considered an American hero. Historians have written about his daring exploits. Teachers have told his story in their classrooms for generations. Countless monuments and historic sites bear his name. He is portrayed as an American patriot and great Indian fighter. All true—if you look only from the white man’s perspective. However, we must always remember history is not one-sided. It is complex, with many, many perspectives to consider. Clark lived in a turbulent time. America, seeking independence, was engaged in a bloody conflict with the British. And caught in the middle were tribes of Native Americans. It was a time when their way of life and surroundings were being reevaluated through a critical European eye. Years among the whites had taken a tragic toll. Some tribes fought with the Americans, some with the British. But despite whose side they were physically fighting on, tribes were actually fighting for life itself. A life that allowed them to choose where to live, hunt, raise their families, and bury their dead according to their own beliefs and traditions. When you read the story of Clark, Indians are presented as “savages.” The truth is, it was a savage time when men of all these nations were fighting for what they believed in. Ironically, they really all wanted the same thing—to live their lives in peace and freedom. They just couldn’t do it together. - Proclamation of George Rogers Clark Day 2018 - The Story of the Painting - 225th Anniversary Exhibit - George Rogers Clark National Historical Park Primary Sources Related to the Clark Campaign - Complete Text of Clark's Memoir - Bowman's Journal - Henry Hamilton's Journal - Letter from Clark to George Mason - Letter of Instruction from Governor Patrick Henry of Virginia Issue of The Indiana Historian on George Rogers Clark and the Fall of Fort Sackville Archaeology Related to Clark and the American Revolution - George Rogers Clark - Archaeology of a Frontier Hero - Archaeology Maze - Learn about Archaeology at American Revolution Websites
Science predicts that eventually, global warming is going to change the overall climate of the Earth. Speculation is that as carbon monoxide gases fill our atmosphere, the temperature will rise, causing the icebergs to melt. Evidence shows the icebergs are gradually melting faster. As they melt, the sea level will rise, eventually covering land we now inhabit. As the sea level rises the air will begin to cool. Over hundreds of years it is thought that the water will refreeze, causing an iceage. It is beleived that this will tremendously impact all life on Earth for the long term, including wiping out more than half of the human population. This will be due to the temperature changes, shortage of food supply, and survival of the fitest.
- like (adj.) - "having the same characteristics or qualities" (as another), Middle English shortening of Old English gelic "like, similar," from Proto-Germanic galika- "having the same form," literally "with a corresponding body" (cognates: Old Saxon gilik, Dutch gelijk, German gleich, Gothic galeiks "equally, like"), a compound of ga- "with, together" + Germanic base lik- "body, form; like, same" (cognates: Old English lic "body," German Leiche "corpse," Danish lig, Swedish lik, Dutch lijk "body, corpse"). Analogous, etymologically, to Latin conform. The modern form (rather than lich) may be from a northern descendant of the Old English word's Norse cognate, glikr. Formerly with comparative liker and superlative likest (still in use 17c.). The preposition (c. 1200) and the adverb (c. 1300) both are from the adjective. As a conjunction, first attested early 16c. The word has been used as a postponed filler ("going really fast, like") from 1778; as a presumed emphatic ("going, like, really fast") from 1950, originally in counterculture slang and bop talk. Phrase more like it "closer to what is desired" is from 1888. - like (v.) - Old English lician "to please, be sufficient," from Proto-Germanic likjan (cognates: Old Norse lika, Old Frisian likia, Old High German lihhen, Gothic leikan "to please"), from lik- "body, form; like, same." The basic meaning seems to be "to be like" (see like (adj.)), thus, "to be suitable." Like (and dislike) originally flowed the other way: It likes me, where we would say I like it. The modern flow began to appear late 14c. (compare please). - like (n.) - c. 1200, "a similar thing" (to another), from like (adj.).
This is the second lesson in this unit. I like to integrate foundational skills and vocabulary skills in a morning message that highlights winter. My second language learners struggle with positional words as well as the difference between he/she, so we review them often. This is a fun way to do it while teaching a little about a season at the same time! Before we do the morning message, I review position words with students as needed. I have student place their hands under their chin, behind their head, over their head, etc. My students have the most trouble with between, so I have the practice putting their head between their hands, placing their hands near each ear. I vary the position words I review from day to day. Write the following on chart paper or on the board: The boy puts a scarf around his neck. He puts a hat on his head. He sleds on the snow. The weather is freezing outside. The season is winter. We read each sentence and students interact with the message by underlining the position words (around, on). I have students talk to partners to identify the capital letter at the beginning of the sentence, sight words and punctuation marks. (Suggestion: Underline the capital letters in green, circle the periods in red, and sight words may be highlighted in yellow.) I ask students what information the morning message gave to show it was winter. Unencumbered read: Seasons & Weather PowerPoint The purpose of this read is for students to get the gist of the text. I stop at the boldfaced words and do a quick step aside explanation of those words. We will examine these words more in depth during the second and third reads of the text, so this is a quick discussion. Slide 3: season- I say: This is a three month period within the year. Slide 4: pattern- I say: The same type of weather is generally seen within each season. revolving- I circle my finger around the earth, following the arrows on slide 4 and say:Revolving means going around something in a circular motion. Here the earth is revolving around the sun. Slide 5: bloom- I say: This is what happens when flowers come or plants open up. hibernate-I say: The bear is hibernating in the log. What do you think it means? migrate- I say: When you go to another place you move. That is what migrate means. Slide 6: breezy- I say: Look at the laundry and the trees in the picture. They are showing you the 'breeze.' What is a breeze or what does it mean when the weather is breezy? Slide 7: scorching- I say:The word before scorching tells you what it means. shade- I say: The umbrellas on the beach make shade and the trees make shade. What do you think shade is? ripe- I say: Ripe means that fruit is ready to eat. Slide 8: harvested- When fruit and vegetables have been picked they have been they chilly-Chilly means a little cold, but not freezing. I continue on each page in the same fashion. As students become aware of the repetitive phrase at the bottom of each page, I encourage them to join in. We will read the text more closely in our second read in the next lesson. The Weather Song This is the second lesson in the unit. We sing The Weather Song many times throughout the unit to remind the kids of what each season brings. It is a fun quick finish to any lesson on seasons and weather and can also help kids remember the seasons. I almost always (sometimes there just isn't an action) give the students some TPR (Total Physical Response) to help them remember the song and the weather types. It is a common strategy used with second language learners, but it can be used with any student! Sing/ Chant “The Weather Song” (Tune: Row, Row, Row your Boat). What is the weather today, I can’t wait to see. Sunny, rainy, windy, cloudy, Which one will it be? For the first line we hold our hands up with palms up as if asking a question. For the second line we point to our eyes. For the third verse we hold up a finger for each type of weather. For the last verse we hold our hands up with palms up as if asking a question. Because this is a unit on Seasons and weather, we will act as meteorologists throughout the unit, observing and recording the daily weather. We want the kids to make personal connections to their learning so they see it as meaningful learning, and this logbook does just that! I ask: What is the date today? We write the date. I ask: What is the weather like outside today? We draw the weather, circle the word that names the weather. I ask: What sentence could we write to go with our weather picture? What words can we use to describe or tell about our picture? We write a simple sentence describing their daily observation (It is sunny. We see rain.). I ask: How many boxes should we color in for our weather today? (one) Do we color from the bottom up or the top down? (bottom up) Students will then record the daily weather on a bar graph in their log.
Article Copyright Wikipedia - Back to Knowledge Base The 5-4-3 rule also referred to as the IEEE way (contrary to the Ethernet way) is a design guideline for Ethernet computer networks covering the number of repeaters and segments on shared-access Ethernet backbones in a tree topology. It means that in a collision domain there should be at most 5 segments tied together with 4 repeaters, with 3 segments containing active senders (i.e. terminals). According to the original Ethernet protocol, a signal sent out over the collision domain must reach every part of the network within a specified length of time. The 5-4-3 rule ensures this. Each segment and repeater that a signal goes through adds a small amount of time to the process, so the rule is designed to minimize transmission times of the signals. For the purposes of this rule, a segment is in accordance with the IEEE definition: an electrical connection between networked devices. In the original 10BASE5 and 10BASE2 Ethernet varieties, a segment would therefore correspond to a single coax cable and any devices tapped into it. On modern twisted-pair Ethernet, a network segment corresponds to the individual connection between end station to network equipment or the connections between different pieces of network equipment. This rule divides a collision domain into two types of physical segments: populated (user) segments, and unpopulated (link) segments. User segments have users' systems connected to them. Link segments are used to connect the network's repeaters together. The rule mandates that there can only be a maximum of five segments, connected through four repeaters, or concentrators, and only three of the five segments may contain user connections. This last requirement applies only to 10BASE5 and 10BASE2 Ethernet segments. This rule is also designated the 5-4-3-2-1 rule with there being two network segments and one collision domain. The 5-4-3 rule was created when 10BASE5 and 10BASE2 were the only types of Ethernet network available. The rule only applies to shared-access Ethernet backbones. The rule does not apply to switched Ethernet because each port on a switch constitutes a separate collision domain. An alternate configuration rule known as the Ethernet way allows 2 repeaters on the single network and does not allow any hosts on the connection between repeaters Click here for original article.
Abraham Lincoln is born: Feb. 12, 1809 On this day in 1809, Abraham Lincoln, who would hold the Union together as the nation’s 16th president, was born in a log cabin near Hodgenville, Ky. As the Civil War raged more than 50 years later, Lincoln insisted that work on the U.S. Capitol Dome continue. He viewed the project as a signal that “we intend the Union shall go on.” Lincoln was the first president to get Congress to levy an income tax. In 1863, Lincoln also got the lawmakers to proclaim Thanksgiving as the nation’s sole federally authorized holiday with religious roots. Fourteen years before his 1860 presidential campaign, Lincoln was elected to the House from Illinois as a Whig anti-war activist. He spoke out against the Mexican-American War, which he saw as evidence of President James Polk’s desire for “military glory — that attractive rainbow that rises in showers of blood.” Lincoln voted with the Whigs and against the Democrats to push through an anti-war resolution on an 82-81 procedural tally. The vote sent a resolution back to a committee with instructions that the panel add the words “a war unnecessarily and unconstitutionally begun by the president of the United States.” While the amendment passed, the underlying bill never reemerged and so was never voted on by the House. The future president hurt his standing when he told the House that “God of Heaven has forgotten to defend the weak and innocent, and permitted the strong band of murderers and demons from hell to kill men, women and children, and lay waste and pillage the land of the just.” Two weeks later, Polk sent a peace treaty to Congress ending the war. When Illinois Democrats branded Lincoln as a demagogue and a slanderer of the president, he decided, given his unpopularity, to spurn politics and earn a living as a lawyer.
Introduction to the Quantitative Reasoning Measure The Quantitative Reasoning measure of the GRE® revised General Test assesses your: - basic mathematical skills - understanding of elementary mathematical concepts - ability to reason quantitatively and to model and solve problems with quantitative methods Some of the questions in the measure are posed in real-life settings, while others are posed in purely mathematical settings. The skills, concepts and abilities are tested in the four content areas below: - Arithmetic topics include properties and types of integers, such as divisibility, factorization, prime numbers, remainders and odd and even integers; arithmetic operations, exponents and roots; and concepts such as estimation, percent, ratio, rate, absolute value, the number line, decimal representation and sequences of numbers. - Algebra topics include operations with exponents; factoring and simplifying algebraic expressions; relations, functions, equations and inequalities; solving linear and quadratic equations and inequalities; solving simultaneous equations and inequalities; setting up equations to solve word problems; and coordinate geometry, including graphs of functions, equations and inequalities, intercepts and slopes of lines. - Geometry topics include parallel and perpendicular lines, circles, triangles — including isosceles, equilateral and 30°-60°-90° triangles — quadrilaterals, other polygons, congruent and similar figures, three-dimensional figures, area, perimeter, volume, the Pythagorean theorem and angle measurement in degrees. The ability to construct proofs is not tested. - Data analysis topics include basic descriptive statistics, such as mean, median, mode, range, standard deviation, interquartile range, quartiles and percentiles; interpretation of data in tables and graphs, such as line graphs, bar graphs, circle graphs, boxplots, scatterplots and frequency distributions; elementary probability, such as probabilities of compound events and independent events; random variables and probability distributions, including normal distributions; and counting methods, such as combinations, permutations and Venn diagrams. These topics are typically taught in high school algebra courses or introductory statistics courses. Inferential statistics is not tested. The content in these areas includes high school mathematics and statistics at a level that is generally no higher than a second course in algebra; it does not include trigonometry, calculus or other higher-level mathematics. The Math Review provides detailed information about the content of the Quantitative Reasoning measure. For more explanations about the concepts covered in the Math Review, view free Khan Academy® instructional videos. The mathematical symbols, terminology and conventions used in the Quantitative Reasoning measure are those that are standard at the high school level. For example, the positive direction of a number line is to the right, distances are nonnegative and prime numbers are greater than 1. Whenever nonstandard notation is used in a question, it is explicitly introduced in the question. In addition to conventions, there are some important assumptions about numbers and figures that are listed in the Quantitative Reasoning section directions. - All numbers used are real numbers. - All figures are assumed to lie in a plane unless otherwise indicated. - Geometric figures, such as lines, circles, triangles and quadrilaterals, are not necessarily drawn to scale. That is, you should not assume that quantities such as lengths and angle measures are as they appear in a figure. You should assume, however, that lines shown as straight are actually straight, points on a line are in the order shown and, more generally, all geometric objects are in the relative positions shown. For questions with geometric figures, you should base your answers on geometric reasoning, not on estimating or comparing quantities by sight or by measurement. - Coordinate systems, such as xy-planes and number lines, are drawn to scale; therefore, you can read, estimate, or compare quantities in such figures by sight or by measurement. - Graphical data presentations, such as bar graphs, circle graphs, and line graphs, are drawn to scale; therefore, you can read, estimate or compare data values by sight or by measurement. More about conventions and assumptions appears in Mathematical Conventions. Quantitative Reasoning Question Types The Quantitative Reasoning measure has four types of questions. Click on the links below to get a closer look at each, including sample questions with rationales. - Quantitative Comparison Questions - Multiple-choice Questions — Select One Answer Choice - Multiple-choice Questions — Select One or More Answer Choices - Numeric Entry Questions Each question appears either independently as a discrete question or as part of a set of questions called a Data Interpretation set. All of the questions in a Data Interpretation set are based on the same data presented in tables, graphs or other displays of data. You can find steps for solving quantitative questions, including useful strategies for answering questions on the Quantitative Reasoning measure, in Problem-solving Strategies. In addition, the pages for each of the four Quantitative Reasoning question types and the Data Interpretation set page, mentioned above, contain strategies specific to answering those types of questions. You are allowed to use a basic calculator on the Quantitative Reasoning measure. For the computer-delivered test, the calculator is provided on-screen. For the paper-delivered test, a handheld calculator is provided at the test center. Read more about using the calculator. - Introduction to the Quantitative Reasoning Measure in Accessible Formats - Math Review - Khan Academy Instructional Videos: Free Preparation for the GRE Quantitative Reasoning Measure - Math Conventions Register for the GRE revised General Test Show schools only the scores you want them to see — only with the ScoreSelect® option. With two full-length, simulated practice tests for the computer-delivered GRE revised General Test. Download it today for Mac® or PC! Get more questions! 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In order for robots to learn new skills faster, all they need is a little help from their Internet friends. At the 2014 Institute of Electrical and Electronics Engineers International Conference on Robotics and Automation in Hong Kong, computer scientists from the University of Washington showed that crowdsourcing information from the online community may be a quick and effective way of teaching robots how to complete tasks, like setting a table or tending a garden. Yes, let’s use the web to hasten their journey to self awareness. According to the scientists, robots can learn how to perform tasks by imitating humans, but such an approach can take a lot of time. For example, showing a robot how to load a dishwasher may require many repetitious lessons to demonstrate how to hold different plates or load things in properly. With this new technique, the robot can turn to the web to get additional input on how to correctly complete the tasks. “We’re trying to create a method for a robot to seek help from the whole world when it’s puzzled by something,” said Rajesh Rao, an associate professor of computer science and engineering at the UW. “This is a way to go beyond just one-on-one interaction between a human and a robot by also learning from other humans around the world.” To demonstrate this theory, the researchers had study participants build models — such as cars, trees, turtles, snakes and more — out of colored Lego blocks, and then asked robots to build the same objects. But since the robots had only witnessed a few examples, they couldn’t fully complete the tasks. So to finish their projects, they turned to the crowd, hiring people from Amazon Mechanical Turk, a crowdsourcing Internet marketplace, to generate more solutions for building the models. From more than 100 crowd-generated models to choose from, the robots picked the best ones to build based on difficulty and similarity to the original objects. The robots then built the best models of each participant’s shape. Such a learning technique is known as “goal-based imitation,” which harnesses the robot’s ability to know what its human operator wants and then come up with the best possible way to achieve that goal. “The end result is still a turtle, but it’s something that is manageable for the robot and similar enough to the original model, so it achieves the same goal,” said Maya Cakmak, a UW assistant professor of computer science and engineering. So sure, the online community may be helpful for these robots, just as long as they stay away from all of the comments sections on YouTube. - This tiny, self-folding robot could one day be part of a large ant-like swarm - By assembling Ikea chairs, robots steal the one job we never wanted - MIT’s ocean-exploring robotic fish takes a test swim through a Fiji reef - This robot can mimic your hand gestures and whoop you at rock-paper-scissors - Meet the British whiz kid who fights for justice with a robo-lawyer sidekick
Activities to help your child with Writing - Support and encourage your child to write their name using the letter formation sheets available in Nursery. - Encourage your child to hold a pencil in a pincer grip. - Support and encourage your child to write for lots of different reasons including: - Birthday cards. - Colouring sheets using pencil crayons. - Wet paintbrushes (using water only) on outside floors and walls. - Ribbons and scarves to practice big formation. - Fingers/sticks in sand/mud. - Chalking on paper/boards/outside floors and walls. - Painting – using fingers or brushes. - Squirty bottles with water in for making shapes on the outside floors and walls.
Drone warships may soon be sailing under their own power using sediment sucked from the sea floor. How does it work? Well, the batteries create current by using the natural fuel sources in the water and from sea bottom dwelling animalcules. Office of Naval Research just did a patent on making energy with a combination of seawater and organic material at the bottom of the ocean. If this can work in large quantities, you can see an unmanned vehicle out there simply burrowing down into the bottom of the ocean trying to recharge. … It’s unmanned systems [like that] that offer tremendous versatility and tremendous reach. These fuel cells convert naturally occurring fuels and oxidants in the marine environment into electricity making them a viable power source for long-term operation of autonomous underwater unmanned vehicles, in-water sensors, and devices used for surveillance and monitoring the ocean environment. Thus far they’re using the technique to power small buoys but with enough research and big enouch batteries you could potentially sail the ocean blue with the slush at the bottom of the sea.
\|Lawrence M. Ward (2008), Scholarpedia, 3(10):1538.\|\|doi:10.4249/scholarpedia.1538\|\|revision #91006 [link to/cite this article]\| Attention refers to the process by which organisms select a subset of available information upon which to focus for enhanced processing (often in a signal-to-noise-ratio sense) and integration. Attention is usually considered to have at least three aspects: orienting, filtering, and searching, and can either be focused upon a single information source or divided among several. Each of these aspects has specific properties that are discussed briefly below. Attention and consciousness are closely related although the two concepts can be both conceptually and empirically distinguished. The simplest way to select among several stimulus inputs is to orient our sensory receptors toward one set of stimuli and away from another. Seeing and hearing are not usually passive, but rather, we actively look or listen in order to see and hear. A prototype for orienting is the response of a dog or a cat to a sudden sound. The animal rapidly adjusts its sense organs, by pricking its ears and turning its eyes, head and/or body, so it can optimally pick up information about the event. Responses such as flicking the eye in the direction of a sound or peripheral movement, as well as accompanying postural adjustments, skin conductance changes, pupil dilation, decrease in heart rate, a pause in breathing, and constriction of the peripheral blood vessels, occur automatically and are collectively referred to as the orienting reflex. The most effective orienting stimuli are loud sounds, suddenly-appearing bright lights, changes in contours, or movements in the peripheral visual field that are not regular, predictable occurrences. It is as though we had an internal 'model' of the immediate world of stimuli around us. When we notice a departure of stimulus input from that model, we reflexively orient to that stimulus in order to update that model as quickly as possible (Sokolov, 1975). If the same stimulus occurs repeatedly it becomes an expected part of our model of the world, and our orienting reflex toward it becomes weaker, even if the stimulus is quite strong. With a change in the nature of the stimulus, however, the reflex recovers to full strength. The overt orienting response to sudden changes in the environment is usually accompanied by another, unseen orienting response, the fixing of attention on the event or object that elicited the reflex. This unseen attentional orienting is called covert orienting. The combination of overt and covert orienting to an event usually results in enhanced perception of that event, including faster identification and awareness of its significance: for example, we can move our eyes to an object (overt attention) or shift attention to it without moving the eyes (covert attention). Although this hidden orienting of attention usually occurs in association with overt orienting, whether reflexive or voluntary, it is possible to covertly attend to an event or stimulus without making any overt sign that we are doing so (e.g., Helmholtz, 1867/1925; Posner, 1980; Wright & Ward, 2008). Thus, covert attention orienting is usually studied separately from overt orienting behaviors, although the two are surely closely related. The premotor theory of attention (e.g., Rizzolatti et al, 1994) proposes that these attention systems are supported by the same neuronal mechanisms, although a detailed examination of the behavioral and physiological data indicates that whereas the two probably share some neural mechanisms they are not identical (see discussions by Corbetta & Shulman, 2002; Wright & Ward, 2008). Stimulus-driven, exogenous, orienting Just as in the orienting reflex, abrupt-onset or intense stimuli can cause covert orienting, that is, they capture attention. For example, abruptly-appearing letters on a computer monitor capture attention and are responded to faster than are gradually-appearing letters (Jonides & Yantis, 1988; Yantis & Jonides, 1984). If such an abrupt-onset stimulus (a direct cue) appears about 100 msec before another stimulus (a target) in the same spatial location, the latter is processed faster and more accurately than if it had appeared in another location (e.g., Müller & Humphreys, 1991), presumably because attention was attracted reflexively to the spatial location of the direct cue. Attention that is captured reflexively in this way is said to be oriented exogenously in a stimulus-driven manner. Attention oriented in this stimulus-driven manner doesn’t remain oriented to the attracting location for long, however, moving to another location after 100-200 msec or so unless the attracting stimulus requires enhanced processing or signals a high probability of a target occurring at that location. Figure 1 displays (in red) the typical time course of exogenously oriented attention at the location of a non-predictive and uninteresting direct cue . Attention also is drawn to the abrupt appearance of a new perceptual object even if its appearance is not accompanied by a luminance change but not to a luminance change that is not associated with the appearance of a new object (Yantis & Hillstrom, 1994). Thus, attention is drawn both to a new perceptual object and to its location (Egeth & Yantis, 1997). Exogenous attention capture also happens in hearing and in touch. Moreover, a direct cue in one of these modalities, say a sound, can orient attention to a location so that when a target in another modality, say a visual pattern, occurs there it too is processed more rapidly and accurately (Wright & Ward, 2008). Part of the cue effect in stimulus-driven orienting appears to be caused by residual sensory activity from the direct cue itself, which also dissipates within 100-200 msec (Wright & Ward, 2008). Indeed, simultaneous presentation of up to 4 direct cues in the same display can cause cue effects at all of their locations (Wright & Richard, 2003). Nonetheless, the cue effect from a single direct cue display is larger than those from multiple cue displays, indicating that cue effects from a single direct cue arise both from orienting attention and from residual sensory activation, whereas those from multiple cue displays arise solely from residual sensory activation (Wright & Richard, 2003). Neurophysiology of stimulus-driven orienting Reflexive attention capture by abrupt or intense stimuli is implemented by a network of brain areas that includes the superior colliculus, the pulvinar nucleus of the thalamus (both subcortical, Figure 2), and the posterior parietal cortex, as well as areas in the frontal cortex and of course the various sensory cortices. Much research suggests that an early model, in which the posterior parietal cortex disengages attention from a current target/location, the superior colliculus shifts it to a new target/location, and the pulvinar nucleus engages attention at that new locus, is roughly correct (Wright & Ward, 2008). Recent imaging research has revealed a more specific picture of the cortical parts of this network, which include the temporal-parietal junction and the ventral-frontal cortex, specifically the inferior frontal gyrus and the middle frontal gyrus, mainly on the right side of the brain (Corbetta & Shulman, 2002). Figure 3 shows in red this right-lateralized ventroparietal network involved in orienting to an abrupt-onset visual stimulus such as a direct cue or an invalidly-cued target. The subcortical areas of the network are hidden in this view. Goal-driven, or endogenous, orienting In addition to reflexive, stimulus-driven orienting, we can also orient attention to a location in space or to an object voluntarily (endogenously) in a goal-driven manner, often based on a cue that tells us where to look or to listen, for example a loudspeaker announcement that passengers from a particular flight will disembark at a particular gate in the airport. Information about where or what to look at or to listen for an expectancy about an environmental event, and we often prepare for the event by orienting attention to the location and to the time of the expected event (LaBerge, 1995). This advance, goal-driven alignment of attention enhances processing of the event when it does happen (e.g., Posner, 1980). Costs and benefits of symbolic cues Goal-driven orienting is usually studied in experiments by presenting a predictive symbolic cue (such as an arrow pointing to a possible target location) as to where in space a target stimulus will occur, the so-called Posner paradigm (e.g. Posner 1980). Usually (say on 80% of arrow-cue trials, which may represent 80% or more of total trials) the target does occur there (called valid-cue trials), giving the subject an incentive to focus attention there in advance of the target’s appearance. Sometimes (on 20% of arrow-cue trials when 80% are valid) the target occurs at a location other than the cued location (called invalid-cue trials). Finally, in some implementations a third group of trials (neutral-cue trials; often 20% of total trials or less) a neutral (as to target location) cue is presented. On these trials targets occur at random at possible locations. Under these conditions, targets on valid-cue trials are responded to faster than are targets on neutral trials (a benefit of orienting to the target location), whereas targets on invalid-cue trials are responded to more slowly than are targets on neutral trials (a cost of orienting to the wrong location). Such goal-driven orienting of attention is slower than is stimulus-driven orienting, taking usually about 300 msec to reach full effectiveness (Shepard & Müller, 1989; Figure 1, green line). Moreover, goal-driven attention can be sustained at a location for quite long periods, even several minutes, whereas stimulus-driven attention is usually transient unless goal-driven attention is invoked by a predictive direct cue or an interesting target stimulus. Goal-driven orienting is not automatic, and can be interrupted by an attention-capturing stimulus (Müller & Rabbitt, 1989), although it can also be sustained even in the presence of such a stimulus if the predictive value of the symbolic cue is high enough (Yantis & Jonides, 1990). Neurophysiology of goal-driven orienting A specific network of brain areas subserves goal-driven attention orienting. The cortical parts are called the dorsoparietal network (Corbetta & Shulman, 2002). Figure 3 shows the right hemisphere of this bilateral network in green. It involves frontal regions, specifically the frontal eye fields (FEF), which seem also to be involved in voluntary orienting to auditory and tactile events (e.g., Shomstein & Yantis, 2004), parietal regions, specifically the intraparietal sulcus (IPS), as well as the relevant sensory cortices and subcortical areas (thalamus and superior colliculus, Figure 2). Moreover, this network interacts with the ventroparietal network (shown in red), probably through connections between the TPJ and the IPS (shown in blue). It is possible that the interactions between the brain regions of the dorsoparietal and ventroparietal networks are mediated by synchronization of their activites at various frequencies, including especially those in the gamma (30-70 Hz) and in the alpha (8-14 Hz) ranges (e.g., Doesburg, et al, 2008; see also Varela et al 2001; Ward, 2003). When attention has been drawn to a particular location or perceptual object and then moves away to another location or object, it seems to be inhibited from returning to the original location or object for a period of up to 2 sec (e.g., Posner & Cohen, 1984; Tipper, Driver, & Weaver, 1991). This is called inhibition of return (IOR). IOR is supposed to promote the search for informative objects or locations, and it occurs within and across visual, auditory and tactile modalities, just as attention does (e.g., Klein, 2000; Spence & Driver, 1998; Ward, 1994), and in infants as young as 6 months of age (Rothbart, Posner, & Boylan, 1990). Although it is possible that IOR arises from inhibition attached to some motor process such as eye movements or manual responses (see Wright & Ward, 2008 for a review of premotor theory in this regard), recent evidence indicates that it is also possible that its neural expression arises during perceptual or cognitive processing of stimuli at previously attended locations (e.g., Prime & Ward, 2006). When attention is oriented to a particular locus in space it is called focal or spatial attention. If it is oriented to a particular object, whether visual, auditory, somatosenory, smell, or taste, it is called object-oriented attention. But whether to a place or to an object, the extent of the attentional focus can be controlled in a goal-driven or a stimulus-driven manner (see Yantis & Serences, 2003, for a review of space-based and object-based attention and their similar cortical mechanisms). The greater the extent over which attention is spread, the less efficient is the processing of information within that area (e.g., Laberge & Brown, 1989). Moreover, the farther a stimulus is away from the center of an attended region, the less efficient is processing (e.g., Eriksen & St. James, 1986). This latter effect is sometimes called the attention gradient. Attention acts as a filter, extracting more information from attended stimuli and suppressing information extraction from unattended stimuli. The suppression can be so great as to cause what has been called inattentional blindness, which occurs for all modalities. The cocktail party phenomenon At a noisy cocktail party (or any other kind) attentional filtering is rampant. People listen to one conversation, line of music, etc. and filter out the rest as 'noise.' Cherry (1953) used shadowing to study this phenomenon in auditory attention. In this technique, an observer must repeat aloud (shadow) one of two continuous speech streams. Close shadowing results in loss of most information in the non-shadowed stream except sometimes for powerful direct cues like one’s own name or a loud noise, which can cause orienting to that stream. The non-shadowed information does get to short-term memory, however, and can be recalled if the shadowing is interrupted. Inattentional and change blindness An analog of auditory shadowing was used to study visual filtering (Neisser & Becklin, 1975). Subjects shadowed one of two overlapping video programs with similar results: most of the information in the non-shadowed stream was not noticed or remembered. Like auditory filtering, visual filtering allows little of the filtered out information to make a lasting impression. Modern replications of this result have produced even more dramatic, and counter-intuitive, results, for example a failure to notice a person in a gorilla suit thumping his chest and cavorting around during a shadowed basketball game (Simons & Chabris, 1999). Even quite dramatic stimuli in simple displays can pass by unnoticed if attention is directed elsewhere. This has been called inattentional blindness (Mack & Rock, 1998). A related phenomenon is change blindness (e.g., Rensink, 2002), in which a scene and the same scene with a change in it are presented for brief periods separated by a blank interval. Until attention alights on the changed element it is not reportable. Neurophysiology of filtering Attentional filtering seems to be accomplished by the activity of the pulvinar nucleus of the thalamus (Figure 2A) under the instructions from other, probably frontal, cortical areas such as the frontal eye fields (FEF; Figure 2B; LaBerge, 1995). The pulvinar nucleus is also supposed to be the subcortical area responsible for engaging attention, and it shows elevated activity when attention must be used to filter out distracting stimuli (e.g., Corbetta, et al., 1991; Laberge & Buchsbaum, 1990). The effect of attending to a specific stimulus on neural activity is manifest quite early in sensory processing and includes both enhanced response to the attended stimulus and inhibited response to other, unattended stimuli. For example, in vision, Moran and Desimone (1985) showed that responses in monkeys' visual area V4 to the same stimulus depended greatly on whether it was attended or ignored. Appropriate attended stimuli in the receptive field of a V4 neuron received a vigorous response that was dramatically reduced when that same stimulus had to be ignored. Similarly, attending to a specific feature of objects in the visual field generates more vigorous responses from the neurons in monkey V4 tuned to those features than it does when attention is directed to other features of the same objects (see review by Maunsell and Treue, 2006). Moreover, gamma-band synchronization of neural responses from different neurons in V4 to the same stimulus is increased by selective attention, whereas synchronization in the alpha-band is decreased, possibly serving to amplify the signal generated by the attended stimuli relative to that generated by distractors (Fries et al, 2001). A good review of these mechanisms that is still current is Kastener and Ungerleider (2000). Dividing attention between two (or more) sources is very difficult. For instance, people can’t easily listen to two simultaneous audio streams or view two overlapping videos while detecting target events in each, especially when the two sources are spatially separated. Sometimes two aspects of a single object can be attended to successfully, but if the two aspects characterize two spatially separated objects performance is worse in divided attention conditions (Bonnel & Prinzmetal, 1998). It is also easier to divide attention between information streams in two different sensory modalities, such as vision and hearing, but if the task is more difficult than simply detecting occasional stimuli in those channels performance is still worse than if attending to only one channel (e.g., Bonnel & Hafter, 1998). When the task is more difficult, only if the task in one modality, say typing by an expert typist, can be performed automatically can attention be divided without a performance decrement, and then only if the response modalities are similarly different (e.g., expert typist typing a text – visual/manual while making a verbal response whenever they hear their name in an auditory channel – auditory/verbal). When we know what we are looking for but don’t know where to find it we must search for it. Attention is importantly involved in this search, and search experiments have yielded much information about its mechanisms. Easy versus difficult search When observers are presented with a field of items to search for a particular target, they can perform the search very quickly, and in roughly the same time regardless of the number of non-target items, if the target differs from the non-targets in a single feature; this is called easy/pop-out/parallel search (Figure 4, green line). If the searcher must detect a conjunction of features, however, the search is slow, and the time to find the target increases linearly with the number of non-targets; this is called difficult/serial search (Figure 4, red line). Easy search could be accomplished by simply detecting the presence of activation in a particular one of the feature maps generated by sensory processing (feature maps are sheets of visual cortex in which activity of particular neurons signals the presence of a particular feature, such as a slanted line, on the retina). This can be done without orienting attention to any one specific item in the field. On the other hand difficult search seems to require focusing attention on each item in turn, which slows the search and makes the overall search time dependent on the number of non-target items (e.g., Woodman & Luck, 1999). Feature integration theory (e.g., Treisman & Gelade, 1980) explains these data by assuming that the binding of features together into a perceptual object requires focal attention to a particular locus. This is not the full story, however, because conjunctions of simple features sometimes also result in a very rapid search (e.g., Wolfe et al, 1989), and attention can be oriented sequentially to items in easy searches and to individual features in conjunction searches (Kim & Cave, 1995). Automatic versus controlled search Much practice on a difficult search task that always demands the same response for a given stimulus gradually turns the process from controlled search, in which search time is a function of the number of items in the search set, to automatic search, in which search time is roughly independent of the number of items in the search set (e.g., Schneider & Shiffrin, 1977; Shiffrin & Schneider, 1977). Search functions for controlled and automatic search resemble those for easy and difficult search (Figure 4). A common explanation for the process of automatization is that attention is slowly withdrawn from task control with increasing practice, until the process requires only a minimal amount and is said to be automatic. In automatic search responses are ballistic, so that they are difficult to inhibit, and also aren’t remembered very well. Many attention lapses in daily life can result from such automatic responses (e.g., Reason, 1984). On the other hand, automatic processing does enable better divided attention performance. Theories of attention Each of the major aspects of attention, orienting, filtering, and search, has spawned numerous theories, both at the psychological and at the neurological level. Early theories, focused on filtering, claimed that information processing in the brain was structurally limited, with an early filter based on physical characteristics such as location and spectral content, that allowed only a selected few stimuli past it (e.g., Broadbent, 1958). Demonstrations that at least some processing is done even on the rejected channels led to the rejection of these early selection theories in favor of late selection theories that hypothesized that all sensory information receives preliminary analysis. The processing bottleneck instead occurs just before entry into longer lasting memory (e.g., Deutsch & Deutsch, 1963). There is physiological evidence favoring both approaches and probably both occur in different circumstances (e.g., Pashler, 1996). Failures of divided attention have led to the idea that attention is a limited resource that, being demanded by one task, is unavailable for another (e.g., Kahneman, 1973). The demonstration that time sharing among perceptual or cognitive tasks is possible, especially if one is overlearned, or automatic, on the other hand has led to the idea that there are multiple attentional resources, and that these can be divided among tasks providing there are no conflicts (e.g., Wickens, 1984). According to this approach, central resources (such as encoding, comparing, remembering) interact with spatial and verbal codes, the sensory modalities, and the response systems to constrain performance. This approach has been criticized as being too flexible (e.g., Navon, 1984), although the idea of limited attentional resources is still used widely. Another class of theories attempts to capture the mechanisms of attention orienting. Some of these have already been mentioned earlier. The approaches of Corbetta and Shulman (e.g., 2002), discussed above (see Figure 3), Laberge (e.g., 1995), and of Shipp (e.g., 2004) are among the most general and useful. Many such theories emphasize the concept of salience, that is that attention orienting is to the most salient of available locations or objects, with salience being a combination of bottom-up and top-down contributions. Shipp (2004) discusses several salience models and combines them all in a theory of the physiology of the orienting system, with a salience map in the pulvinar nucleus of the thalamus combining inputs from other such maps throughout the brain. In this theory, IOR is explained by a decrement in the salience of a location or object that has been inspected recently. See Saliency_Map & Visual_Salience Finally, there are other models that attempt to capture particular aspects of attention in computational or mathematical frameworks. The episodic theory of Sperling and Weichselgartner (1995) is particularly general, and accommodates a variety of possible mechanisms. In this approach, general transition functions of time are assumed for attention movement and onset and offset at particular locations. These temporal functions refer to an attention spotlight that can have a variety of characteristics such as extent and intensity. Thus the theory can accommodate a variety of results from studies of all of the aspects discussed earlier. More recently, Taylor (e.g., Taylor & Rodgers, 2002, CODAM Model) has proposed a control model of attention movement that is expressed as a neural network and that is neurophysiologically realistic. There are also theories of attentional oscillations and the entrainment of attentional focus to rhythmical events such as music (e.g., Large & Jones, 1999). These dynamical theories are also mathematical, since the description of oscillators is. None of these theories has yet gained universal acceptance. Follow the links below to reach discussions of several specific theories. Attention and consciousness Attention is closely related to consciousness. Both are integrative and yet also selective. Inattentional blindness seems to indicate that items not in attention are not consciously perceived. Indeed so close is this relationship that Taylor’s CODAM model of attention is asserted also to provide, through the corollary discharge of the attention control signals, two important aspects of consciousness, viz. the sense of ownership of the conscious experience and its immunity to error though misidentification. Nonetheless, the two concepts are differentiable. Attention is usually conceptualized as the boosting of signal-to-noise ratio both through inhibition of processing of unattended stimuli and through enhanced processing of attended stimuli. Consciousness refers primarily to phenomenal experience itself, and secondarily to aspects of that experience such as its wholeness, its feeling of self-ownership (first-person ontogeny), the ability to report its contents verbally or in other ways, and the awareness of being conscious (metaconsciousness). There are several models of the relationship between attention and primary, or phenomenal, consciousness, including that assumed by Taylor and most others in which cognitive material (sensations, perceptions, cognitions, memories, etc.) are either attended or unattended, with the attended items being experienced and also reportable, etc. (Figure 5, top). One competing model, among others, has all cognitive material being either conscious or unconscious, with attention selecting some of the conscious material for enhanced processing, rendering it reportable (Figure 5, bottom; e.g., Lamme, 2003). Lamme’s model assumes that all reentrant neural processing gives rise to conscious experience but that only experience selected by attention is reportable. This implies that there can be consciousness without attention but that only conscious material can be attended to. In contrast, Koch and Tsuchiya (2007) adduce evidence for a more complete dissociation between the two, that is, for attention both with and without consciousness, and consciousness both with and without attention. In this latter view, attention and consciousness are separate processes in the brain but have close links. As yet there is no definitive way to choose among these models. - Bonnel A-M Hafter E. (1998) Divided attention between simultaneous auditory and visual signals. Percep. Psychophys. 60:179--190. - Bonnel A-M Prinzmetal W. (1998) Dividing attention between the color and the shape of objects. Percep. Psychophys. 60:113-124. - Broadbent DE. (1958) Perception and communication. 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Not a Member? Email this page Send the page "" to a friend, relative, colleague or yourself. Separate multiple email address with a comma We do not record any personal information entered above. Thank you. Your email has been sent. Share this page This time of year can be difficult for patients sensitive to environmental factors that can trigger symptoms related to asthma and allergies. Warmer weather means that common allergens in the air, such as pollen and mold, will flourish. Other allergens that can trigger asthma attacks include dust, animal dander, drugs, and food additives. Viral respiratory infections and physical exertion can also initiate asthmatic attacks. Allergies and asthma often occur together. Asthma is categorized as either allergic (extrinsic) or non-allergic (intrinsic). Allergic responses can lead to asthma symptoms when antibodies misidentify a typically harmless substance, such as pollen, as an invader. Antibodies bind to the allergen and the immune system releases chemicals that lead to allergy symptoms. For some patients, this same reaction also affects the lungs and airways, leading to asthma symptoms. The yearly trend has been for increased length of allergy seasons and higher pollen counts, so we can anticipate higher numbers of patients reporting symptoms this season as well. Sometimes patients are not aware they have asthma because they may not have severe symptoms. Since asthma can become life-threatening, it is important to keep patients informed of typical symptoms. Common asthma symptoms include: coughing, especially at night, with exercise, or when laughing; difficulty breathing; tightness in the chest; and wheezing. Some patients have a chronic cough as the only symptom. Patients may experience symptoms most often in the night or morning, but they can occur at any time, especially if patients are exposed to substances that are triggers for them. When treating patients, the best treatment strategy is prevention. Patients should be instructed to be aware of what situations prompt an attack, such as exposure to allergens, respiratory infections, and cold weather, and should be encouraged to avoid these situations. Beyond this, if a patient has asthma attacks that are severe, unpredictable, or occur more than twice a week, then the recommendation is for treatment with a long-term control medication. These preventive medications are taken daily to achieve and maintain control of asthma symptoms. A common and effective medication type for controlling asthma is inhaled corticosteroids. These anti-inflammatory medications can improve asthma control and normalize lung function. Other medications typically used for long-term control of asthma are long-acting beta-agonists (LABAs), cromolyn, theophylline, leukotriene modifiers, and immunomodulators. Quick-relief medications include short-acting beta-agonists (SABAs), which relax airway muscles to give rapid relief of symptoms and are to be used in patients only as needed, for symptomatic relief. Immunotherapy (allergy vaccinations) may provide patients relief from symptoms brought on by trigger allergens that cannot be avoided. Immunotherapy increases a patient’s tolerance to those trigger allergens. Allergy treatments include antihistamines, montelukast, immunomodulators, and oral corticosteroids. There are a few treatments that help both asthma and allergies, such as the leukotriene modifier, montelukast; immunotherapy; oral steroids; and anti-immunoglobulin E (IgE) therapy. Prevention and control are primary goals for the protection of our patients' respiratory health. Unfortunately, the death rate and prevalence of asthma has increased significantly since the late 1970s. The impact is widespread, with estimates showing that approximately 26 million Americans have asthma and that the asthma mortality is near 4,000 deaths per year. Historical reports show that each year patients with asthma make approximately 13.9 million visits to doctors and 1.4 million visits to hospital outpatient departments, and that asthma is responsible for approximately 456,000 hospitalizations and 2.1 million emergency room visits. Any delay in administering appropriate drug therapy can lead to severe or even fatal asthma attacks. Patients should be reminded to never change or discontinue preventive medications, and to always keep an adequate supply available. It is important to work with patients to determine the best treatment to manage their symptoms, and also to continue regular consultations, since allergy and asthma symptoms can change over time. PDR Network can be a useful resource for information on asthma and allergy drugs, as well as other drug types, offering alerts and specific product labeling. Keep current with information on products like those used to treat asthma and allergies by using PDR.net. Salvatore Volpe, MD, FAAP, FACP, CHCQM Chief Medical Officer
Social science shows us that youth thrive when they develop strong goal management skills that support positive trajectories. These goal management skills comprise an internal navigation system of sound reasoning—one that selects optimum goals and strategies to achieve life aspirations. Research has teased out components of goal management that conveniently line up with the acronym GPS, just like a car’s navigational system. GPS stands for: Goal Selection —“Where do I want to go?” Pursuit of Strategies —“What is the best way to get there?” Shifting Gears —”How do I compensate when the road gets rough? Why is GPS Important? GPS presents a more dynamic and realistic approach to pursuing goals. Goal management emphasizes both skill development and fluid process, a departure from past practices which have depended namely on “goal setting”. How Does GPS Influence Programming? Just as we use GPS to find and navigate towards destinations, we can use youth programming to align and navigate participants towards future goals. While goal setting is usually the most difficult part of a given program—because it takes time to develop, it’s different for every individual, and most youth and adults are new to the concepts—it’s important to include goal management as an integral part of the Camp Fire experience, because youth will take the skills they’ve learned in your program and apply them for years after they graduate from it. Here are some key goal setting strategies that you may want to incorporate into your lessons (hint: GPS activities make for some great reflections): 1. Goals do not need to be distant. Most youth cannot articulate a long-term goal that they can actually work on, or else, their long-term goal needs to be divided into closer and closer benchmarks so that something is on the immediate horizon. Youth want to be able to get started right away! 2. Goals do not need to be skills or achievements. Some youth may have goals about creating better relationships with their friends or family members, or may wish to be able to handle their anger in more constructive ways. Goals need not be a clear improvement in knowledge or skills as can be evaluated numerically, such as passing a test or improving a grade. It’s important to foster the kinds of thinking that allow youth to connect their goals to the fabric of their communities: peer group, school, family, town, etc. 3. Complex goals need to be made simpler. Break long-term, complex goals down into simpler, shorter, possible-to-achieve steps. One can’t learn guitar in a day, or even in a year, simply by stating that they want to learn guitar. There are several intermediate steps, which could be charted and checked: saving X amount of money, buying a used guitar and strings, looking up and memorizing basic chords, practicing basic cords for X hours each day, asking X people who already play guitar for pointers or to set up lessons, etc. Each of these steps requires practice, changing of strategies, requesting help, learning from mistakes and from others, and staying focused on the larger goal while meeting achievable benchmarks. 4. Goals change! Sometimes we set out with a goal in mind, and even make a detailed chart to track smaller steps and benchmarks, but then in the middle of the process realize the goal needs to be changed or even scrapped. That’s okay! If we use a Growth Mindset to analyze the situation, we will see that there will be many lessons learned during the process—lessons that might be just as valuable, if not more, than reaching the original goal in the first place. Youth, especially, will take different roads that adults maybe hadn’t even thought of. It’s good to encourage deviation from the original plan, along with a re-calibration of destinations and intermediary steps, so that youth gain resiliency and creativity along the way. Goal management lends itself to programs with longer duration and opportunities to gauge progress over time. An example GPS applied in an academic and service learning setting from Camp Fire Columbia:
17q12 duplication is a chromosomal change in which a small piece of chromosome 17 is copied (duplicated) abnormally in each cell. The duplication occurs on the long (q) arm of the chromosome at a position designated q12. Signs and symptoms related to 17q12 duplications vary significantly, even among members of the same family. Some individuals with the duplication have no apparent signs or symptoms, or the features are very mild. Other individuals can have intellectual disability, delayed development, and a wide range of physical abnormalities. Intellectual and learning ability in people with 17q12 duplications ranges from normal to severely impaired. Many affected individuals have delayed development, particularly involving speech and language skills and gross motor skills such sitting, standing, and walking. Seizures are also common. Behavioral and psychiatric conditions that have been reported in people with 17q12 duplications include autism spectrum disorder (which affects social interaction and communication), schizophrenia, aggression, and self-injury. About half of affected individuals have an unusually small head (microcephaly). Less commonly, 17q12 duplications have been associated with abnormalities of the eyes, heart, kidneys, and brain. Some individuals with this chromosomal change have subtle differences in facial features, although these are not consistent. 17q12 duplications appear to be uncommon. Several dozen people with this chromosomal change have been described in the medical literature. Most people with 17q12 duplications have an extra copy of about 1.4 million DNA building blocks (base pairs), also written as 1.4 megabases (Mb), at position q12 on chromosome 17. This duplication affects one of the two copies of chromosome 17 in each cell. The duplicated segment is surrounded by short, repeated sequences of DNA that make the segment prone to rearrangement during cell division. The rearrangement can lead to extra or missing copies of DNA at 17q12. (A missing copy of this segment causes a related chromosomal condition called 17q12 deletion syndrome.) The segment of 17q12 that is most commonly duplicated includes at least 15 genes. It is unclear which of these genes, when present in more than one copy, contribute to intellectual disability, delayed development, and the other signs and symptoms described above. Because some people with a 17q12 duplication have no obvious intellectual or physical problems, researchers suspect that additional genetic factors may influence whether a person has signs and symptoms related to the chromosomal change. 17q12 duplications have an autosomal dominant pattern of inheritance, which means one copy of the duplication in each cell is sufficient to cause the signs and symptoms. Most 17q12 duplications are inherited from a parent. In these cases, the parent most often has only mild signs and symptoms or no related features at all. Less commonly, 17q12 duplications represent a new (de novo) chromosomal change and occur in people with no history of the duplication in their family. - 17q12 duplication syndrome - 17q12 microduplication - 17q12 microduplication syndrome - 17q12 recurrent duplication - chromosome 17q12 duplication syndrome - recurrent duplication of 17q12
Microfilaments (or actin filaments) are the thinnest filaments of the cytoskeleton found in the cytoplasm of all eukaryotic cells. These linear polymers of actin subunits are flexible and relatively strong, resisting buckling by multi-piconewton compressive forces and filament fracture by nanonewton tensile forces. Microfilaments are highly versatile, functioning in (a) actoclampin-driven expansile molecular motors, where each elongating filament harnesses the hydrolysis energy of its "on-board" ATP to drive actoclampin end-tracking motors to propel cell crawling, ameboid movement, and changes in cell shape, and (b) actomyosin-driven contractile molecular motors, where the thin filaments serve as tensile platforms for myosin's ATP hydrolysis-dependent pulling action in muscle contraction and uropod advancement. Actin filaments are assembled in two general types of structures: bundles and networks. Actin-binding proteins dictate the formation of either structure since they cross-link actin filaments in the double-stranded helix. In non-muscle actin bundles, the filaments are held together such that they are parallel to each other by actin-bundling and/or cationic species. Bundles play a role in many cellular processes such as cell division (cytokinesis) and cell movement. In vitro self-assembly The thinnest fibers of the cytoskeleton (measuring approximately 7 nm in diameter), microfilaments are formed by the head-to-tail polymerization of actin monomers (also known as globular or G-actin). Actin subunits as part of a fiber at referred to as filamentous actin (or F-actin). Each microfilament is made up of two helical interlaced strands of subunits. Much like microtubules, actin filaments are polarized, with their fast-growing (+)-ends (also known as barbed ends, because of their appearance in electron micrographs after binding of myosin S1 sub-fragments) and a slow-growing (-)-end (or pointed end, again based on the pattern created by S1 binding). Filaments elongate approximately 10 times faster at their plus (+) ends than their minus (-) ends. At steady-state, the polymerization rate at the plus end matches the depolymerization rate at the minus end, and microfilaments are said to be treadmilling. A treadmilling filament need not move; even so, there is a net monomer uptake at the (+)-end and a net monomer loss from the (-)-end, such that the overall length a treadmilling microfilament does not change. Notably, no mechanical force is generated by treadmilling. In vitro actin polymerization, nucleation, starts with the self-association of three G-actin monomers to form a trimer. ATP-actin then binds the plus (+) end, and the ATP is subsequently hydrolyzed with a half time of about 2 seconds and the inorganic phosphate released with a half-time of about 6 minutes, which reduces the binding strength between neighboring units and generally destabilizes the filament. In vivo actin polymerization is catalyzed by a new class of filament end-tracking molecular motors known as actoclampins (see next section). Recent evidence suggests that ATP hydrolysis can be prompt in such cases (i.e., the rate of monomer incorporation is matched by the rate of ATP hydrolysis). ADP-actin dissociates slowly from the minus end, but this process is greatly accelerated by ADP-cofilin, which severs ADP-rich regions nearest the (–)-ends. Upon release, ADP-actin undergoes exchange of its bound ADP for solution-phase ATP, thereby forming the ATP-actin monomeric units needed for further (+)-end filament elongation. This rapid turnover is important for the cell's movement. End-capping proteins such as CapZ prevent the addition or loss of monomers at the filament end where actin turnover is unfavourable like in the muscle apparatus. Microfilament-based motility by actoclampin molecular motors Intracellular actin cytoskeletal assembly and disassembly are tightly regulated by cell signaling mechanisms. Many signal transduction systems use the actin cytoskeleton as a scaffold holding them at or near the inner face of the peripheral membrane. This subcellular location allows immediate and exquisite responsiveness to transmembrane receptor action and signal-processing enzyme cascades. Because actin monomers must be recycled to sustain high rates of actin-based moltility during chemotaxis, cell signalling is believed to activate cofilin, an actin-filament depolymerizing protein which binds to ADP-rich actin subunits nearest the filament's (-)-end and promotes filament fragmentation, with concomitant depolymerization to liberate actin monomers. The protein profilin enhances the ability of monomers to assemble by stimulating the exchange of actin-bound ADP for solution-phase ATP to yield Actin-ATP and ADP. In most animal cells, monomeric actin is bound to profilin and thymosin-beta4, both of which preferentially bind with one-to-one stoichiometry to ATP-containing monomers. Although thymosin-beta4 is strictly a monomer-sequestering protein, the behavior of profilin is far more complex. Profilin is transferred to the leading edge by virtue of its PIP2 binding site, and profilin also employs its poly-L-proline binding site to dock onto end-tracking proteins. Once bound, Profilin-Actin-ATP is loaded into the monomer-insertion site of actoclampin motors (see below). Another important component in filament formation is the Arp2/3 complex, which binds to the side of an already existing filament (or "mother filament"), where it nucleates the formation of a new actin filament and creates a fan-like branched filament network. In non-muscle cells, actin filaments are formed at/near membrane surfaces. Their formation and turnover are regulated by many proteins, including - Filament end-tracking protein (e.g., formins, VASP, N-WASP) - Filament-nucleator known as the Actin-Related Protein-2/3 (or Arp2/3) complex - Filament cross-linkers (e.g., α-actinin and fascin) - Actin monomer-binding proteins profilin and thymosin-β4 - Filament (+)-end cappers such as Capping Protein and CapG, etc. - Filament-severing proteins like gelsolin - (-)-End depolymerizing proteins such as ADF/cofilin The actin filament network in non-muscle cells is highly dynamic. As first proposed by Dickinson & Purich (Biophysical Journal 92: 622-631), the actin filament network is arranged with the (+)-end of each filament attached to the cell's peripheral membrane by means of clamped-filament elongation motors ("actoclampins") formed from a filament (+)-end and a clamping protein (formins, VASP, Mena, WASP, and N-WASP). The primary substrate for these elongation motors is Profilin-Actin-ATP complex which is directly transferred to elongating filament ends (Dickinson, Southwick & Purich, 2002). The (-)-end of each filament is oriented toward the cell's interior. In the case of lamellipodial growth, the Arp2/3 complex generates a branched network, and in filopods, a parallel array of filaments is formed. Actoclampins are the actin filament (+)-end-tracking molecular motors that generate the propulsive forces needed for actin-based motility of lamellipodia, filopodia, invadipodia, dendritic spines, intracellular vesicles, and motile processes in endocytosis, exocytosis, podosome formation, and phagocytosis. Actoclampin motors also propel such intracellular pathogens as Listeria monocytogenes, Shigella flexneri, Vaccinia and Rickettsia. When assembled under suitable conditions, these end-tracking molecular motors can also propel biomimetic particles. The term actoclampin is derived from acto- to indicate the involvement of an actin filament, as in actomyosin, and clamp to indicate a clasping device used for strengthening flexible/moving objects and for securely fastening two or more components, followed by the suffix -in to indicate its protein origin. An actin filament end-tracking protein may thus be termed a clampin. Dickinson and Purich (2002) recognized that prompt ATP hydrolysis could explain the forces achieved during actin-based motility. They proposed a simple mechanoenzymatic sequence known as the Lock, Load & Fire Model, in which an end-tracking protein remains tightly bound ("locked" or clamped) onto the end of one sub-filament of the double-stranded actin filament. After binding to Glycyl-Prolyl-Prolyl-Prolyl-Prolyl-Prolyl-registers on tracker proteins, Profilin-ATP-actin is delivered ("loaded") to the unclamped end of the other sub-filament, whereupon ATP within the already clamped terminal subunit of the other subfragment is hydrolyzed ("fired"), providing the energy needed to release that arm of the end-tracker, which then can bind another Profilin-ATP-actin to begin a new monomer-addition round. The following steps describe one force-generating cycle of an actoclampin molecular motor: - The polymerization cofactor profilin and the ATP·actin combine to form a profilin-ATP-actin complex that then binds to the end-tracking unit - The cofactor and monomer are transferred to the (+)-end of an actin already clamped filament - The tracking unit and cofactor dissociate from the adjacent protofilament, in a step that can be facilitated by ATP hydrolysis energy to modulate the affinity of the cofactor and/or the tracking unit for the filament; and this mechanoenzymatic cycle is then repeated, starting this time on the other sub-filament growth site. When operating with the benefit of ATP hydrolysis, AC motors generate per-filament forces of 8–9 pN, which is far greater than the per-filament limit of 1–2 pN for motors operating without ATP hydrolysis (Dickinson and Purich, 2002, 2006; Dickinson, Caro and Purich, 2004). The term actoclampin is generic and applies to all actin filament end-tracking molecular motors, irrespective of whether they are driven actively by an ATP-activated mechanism or passively. Some actoclampins (e.g., those involving Ena/VASP proteins, WASP, and N-WASP) apparently require Arp2/3-mediated filament initiation to form the actin polymerization nucleus that is then "loaded" onto the end-tracker before processive motility can commence. To generate a new filament, Arp2/3 requires a "mother" filament, monomeric ATP-actin, and an activating domain from Listeria ActA or the VCA region of N-WASP. Ther Arp2/3 complex binds to the side of the mother filament, forming a Y-shaped branch having a 70 degree angle with respect to the longitudinal axis of the mother filament. Then upon activation by ActA or VCA, the Arp complex is believed to undergo a major conformational change, bringing its two actin-related protein subunits near enough to each other to generate a new filament gat. Whether ATP hydrolysis may be required for nucleation and/or Y-branch release is a matter under active investigation. - Pollard T. D., Earnshaw W. D. (2004). Cell Biology, First Edition, SAUNDERS. ISBN 1-4160-2388-7. - MeSH Microfilaments - MeSH Microfilament+proteins - Microfilament at eMedicine Dictionary - m_14z/12533650 at Dorland's Medical Dictionary Proteins of the cytoskeleton \|Microfilaments\|\|Actins - Actin-binding proteins - Actinin - Arp2/3 complex - Cofilin - Destrin - Gelsolin - Myosins - Profilin - Tropomodulin - Troponin (T, C, I) - Tropomyosin - Wiskott-Aldrich syndrome protein\| \|Intermediate filaments\|\|type 1 and 2 (Cytokeratin, type I, type II) - type 3 (Desmin, GFAP, Peripherin, Vimentin) - type 4 (Internexin, Nestin, Neurofilament, Synemin, Syncoilin) - type 5 (Lamin A, B)\| \|Microtubules\|\|Dyneins - Kinesins - MAPs (Tau protein, Dynamin) - Tubulins - Stathmin - Tektin\| \|Catenins\|\|Alpha catenin - Beta catenin - Plakoglobin (gamma catenin) - Delta catenin\| \|Nonhuman\|\|Major sperm proteins - Prokaryotic cytoskeleton (Crescentin, FtsZ, MreB)\| \|Other\|\|APC - Dystrophin (Dystroglycan) - plakin (Desmoplakin, Plectin) - Spectrin - Talin - Utrophin - Vinculin\|
innate ideas, in philosophy, concepts present in the mind at birth as opposed to concepts arrived at through experience. The theory has been advanced at various times in the history of philosophy to secure a basis for certainty when the validity or adequacy of the observed functioning of the mind was in question. Plato, for example, asserted the inadequacy of knowledge arrived at through sense experience; the world apparent to sense was only a temporal, changing approximation of an eternal, unchanging reality. The next important occurrence of a doctrine of innate ideas, not directly based on Plato, is in the work of René Descartes. Among the ideas Descartes took to be innate were the existence of the self: cogito ergo sum [I think, therefore I am], the existence of God, and some logical propositions like, from nothing comes nothing. John Locke, objecting that the doctrine encouraged dogmatism and laziness in thinking, advanced the classic attack on innate ideas. He argued that if certain ideas were innate they would be universally held and used, which is not the case. In contemporary discussion the question of innate resources of the mind has been the subject of dispute between behavioral psychologist B. F. Skinner and linguistic theorist Noam Chomsky. Chomsky has pointed out that the learning of a language and linguistic performance cannot be adequately explained by the empirical behaviorist model.
Saving the world's most threatened birds… Stark Realities…What’s the best way to save a species? Should we target conservation at individual sites, or perhaps use a much broader approach - taking action at the landscape or seascape scale? For 99% of Globally Threatened Birds, safeguarding Important Bird Areas (IBAs) is a key part of the solution. Questions of scale for conservation programmes are the subject of a paper by scientists from BirdLife International and Conservation International published in the inaugural issue of Conservation Letters. The study identified the most appropriate spatial scale of conservation efforts for 4,239 species of birds, mammals, amphibians and reptiles on the IUCN Red List.Experts classified each species into one of four conservation strategies. The results were stark. “For 79% of threatened bird species, the highest priority conservation action in the immediate future is to provide effective safeguarding of individual IBAs or networks of IBAs”, said Dr Stuart Butchart, BirdLife’s Global Research Coordinator and a co-author on the paper. Illustrating the importance of site-based conservation is the Pico da Vara IBA (Azores, Portugal). The reserve holds the entire world population of the Critically Endangered Azores Bullfinch Pyrrhula murina. Habitat loss and exotic plant invasion have heavily impacted the population, leaving about 370 birds remaining. The IBA has now been designated a Special Protected Area – providing sanctuary and a glimmer of hope for the future. In the longer term, all site-based approaches must also consider issues in the surrounding areas. For some threatened species, the need is more urgent. The scientists discovered that for 20% of birds, IBA or local-scale protection also needs to be reinforced with broader-scale action in the short term.Seabirds killed by long-line fishing, waterbirds affected by hydrological processes across a landscape, and species occurring at low population densities and impacted by hunting are just three examples. “We must act at multiple spatial scales to protect Critically Endangered species like Balearic Shearwater Puffinus mauretanicus, Brazilian Merganser Mergus octosetaceus and Blue-throated Macaw Ara glaucogularis/i>” said Dr Butchart. Of all threatened birds, fewer than 1% are best conserved in the short term primarily through action at the landscape scale. “These include species like the Critically Endangered Indian Vulture Gyps indicus, which is threatened as a result of poisoning by the veterinary drug Diclofenac” commented Dr Butchart. “Action is needed to ensure stocks of the drug are replaced with safe alternatives throughout the range of the species”. “The results for mammals, amphibians, tortoises and turtles were remarkably similar to birds… but with clear differences between terrestrial, freshwater, and marine species”, commented Charlotte Boyd of Conservation International and lead author. As the world’s leading authority on bird conservation, BirdLife maintains the list of globally threatened species on behalf of the IUCN. At present one in eight of the world’s 10,000 birds are at risk of extinction, and 190 bird species are Critically Endangered. The analysis presented in Conservation Letters is a good example of the strong science underpinning the BirdLife Preventing Extinctions Programme. The campaign is taking action to save the most threatened bird species on the planet. 4th July 2014
Anyone who has ever cut down a tree is familiar with the rings radiating out from the center of a tree trunk marking the tree's age. Careful study of tree rings can offer much more: a rich record of history and indications of concerns for the future. Read more in this news release. Credit: Matthew Salzer, University of Arizona Brendan Buckley of Lamont-Doherty Earth Observatory of Columbia University and his colleagues have put together a high-resolution record of periods of drought and moisture in Southeast Asia that is over three quarters of a millennium long from 1250 to 2008 AD. Just as satellite photos do--large sets of information like this tree ring data bring into focus patterns and phenomena that are larger than one lifetime. Read more in this news release. Credit: Zina Deretsky, National Science Foundation Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air. They have discovered that eruptions also affect rainfall over the Asian monsoon region, where seasonal storms water crops for nearly half of Earth's population. Find out more in this news release. Newly discovered ancient, mummified trees may reveal clues about future ecosystem responses to climate change. Ohio State University Earth scientist Joel Barker spotted pieces of dead trees scattered on the barren ground near a glacier. The trees probably died in a landslide, as indicated by deposits still present on surrounding material. Read more in this Discovery. Credit: Joel Barker, Byrd Polar Research Center, Ohio State University The Division of Atmospheric and Geospace Sciences (AGS) of the Directorate for Geosciences supports research to add new understanding of the behavior of the earth's atmosphere and its interactions with the sun. A new, 1,238-year-long tree-ring chronology, the longest and most accurate of its kind for Mesoamerica, is the first to reconstruct the climate of pre-colonial Mexico on an annual basis for more than a millennium, pinning down four ancient megadroughts to their exact years. In this special report, leading climate change experts discuss one of the most complex scientific puzzles ever to confront humankind. For the topic, How Do We Know?, they talk about using proxies, including tree rings and ice cores, to reconstruct the long history of the Earth's climate. April 4, 2011 Lord of the Tree Rings Tree rings are nature's historians Trees are outstanding historians. In fact, scientists dating back to Leonardo da Vinci recognized the value of trees. While others had figured out that you could determine the age of a tree by counting its growth rings, da Vinci went beyond that basic knowledge. "He was a genius and realized also that the width of those growth rings carried information about the environmental conditions during each year the rings were formed," says David Stahle, director of the Tree Ring Laboratory at the University of Arkansas. "So, he really anticipated the entire science of dendrochronology using annual growth rings from trees to infer past environmental variability, especially climate variability," continues Stahle, a professor in the university's Geosciences Department. "The time series of fat rings versus skinny rings is telling you about the history of wet years versus dry years." Along with colleagues from the National Laboratory of Dendrochronology at the Mexican Forest Research Institute, Stahle collects tree-ring samples from remote forests, far from human influence. With support from the National Science Foundation (NSF), Stahle is now developing tree-ring records of Mexico's climate variability. "Mexico has suffered persistent drought and we've done research on this using both the instrumental record and tree-ring reconstructions. One notion is that this 21st century drought may be being aggravated by human activity, both at the global scale and at the regional scale due to land surface changes," explains Stahle. "Not only is Mexico vulnerable to water availability, but her hydroelectric power supply system is also vulnerable to climate variations and drought. Mexico has had a notorious history of drought that has interacted with food supply availability, famine and disease, and has resulted in catastrophic population loss in the colonial history of that country." So how do scientists extract a tree-ring core as thick as a pencil without harming the tree? The key is a tool called a Swedish increment borer, invented more than 100 years ago to test the growth rate of living trees. It's basically a long, hollow steel auger. "This increment borer can be screwed into the center of the tree and it extrudes a core inside the long drill bit. You then remove the core from the auger with a long thin steel foil called an extraction spoon," Stahle says. It does take practice and a little elbow grease! But, if done properly there's no permanent damage to the tree. In addition to offering a history of weather, these tree rings also offer some insight into how our ancestors lived, such as the climate extremes they suffered and the construction and abandonment of their settlements. In fact, under a microscope, experts can determine in exactly what year a barbed wire fence made a wound into a tree, helping to settle modern property disputes. Tree rings may also help solve some of history's mysteries. For example, Stahle believes drought may have played a part in the New World's "Lost Colony" of Roanoke. "This is the drought of 1587, '88, and '89. That was the most severe drought of 800 years in this part of the United States, and 1587 was a particularly significant year because Virginia Dare, the first English baby born in the New World, and the other colonists at the Roanoke colony in North Carolina, were last seen in the summer of 1587," says Stahle, pointing to some extremely skinny rings on a piece of bald cypress from Blackwater River, Virginia. So what trees do these experts like to study most? "In the pantheon of tree species for dendrochronology, there are a few that are the crème de la crème, if you will--the very best species in the world. There are a limited number of them and really, in North America, it would be the Douglas fir, especially grown on arid sites in the interior of the continent," says Stahle. Also among his favorites: ponderosa pine, the southern bald cypress in the United States, and the Montezuma bald cypress in Mexico. His work also involves the bigger picture of protecting the world's forests. "These forests are being cleared and cut even today because progress marches on. So it's kind of a burden on the dendrochronological community to try to identify these relic old-growth forests that are still found and still threatened in many parts of our country," notes Stahle. "But, it's a great pleasure to travel to remote areas in the United States or Mexico to original forests, even virgin forests, with old growth trees, and there are precious few of these locations left. I think they're aesthetically beautiful; these old growth forests are important from an ecological perspective, and for the climate histories they preserve in their annual rings." Any opinions, findings, conclusions or recommendations presented in this material are only those of the presenter grantee/researcher, author, or agency employee; and do not necessarily reflect the views of the National Science Foundation.

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