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Gravity is the force that makes things fall to the ground on Earth and holds the planets in their orbits (paths) around the Sun. The force of gravity acts over immense distances between objects in the Universe and holds them all together. The gravitational force between objects increases with their MASS. It also increases the closer they are. The gravity between objects on Earth is usually too small to notice. On Earth, objects have a point, often near their centre, which is called their centre of gravity. The lower it is, the more stable they are. Cars are designed with their heavy engines near to the ground, to keep their centre of gravity low. This means they can corner at speed without tipping over. Which falls faster, a ball or a feather? In Earth’s atmosphere, the ball reaches the ground first because air resistance slows the feather down. In a vacuum, there is no air and therefore no air resistance. The feather and the pool ball fall at the same rate because gravity pulls them with exactly the same amount of force. The mass of an object is the amount of matter it contains. The greater the mass of an object, the more matter it contains, and the more it pulls on other objects with the force of gravity. The mass of an object does not vary unless the amount of matter inside it changes for some reason. Mass is measured in kilograms (kg).
Perfect Sentence Challenge In any grammar course, a teacher can check to see if the students are learning the content by giving them a simple challenge. At the beginning or the end of any class, the teacher can tell the students to write a sentence that is an example of something covered in class (e.g., in the past progressive tense, with a compound subject, with the verb "tell" in the past). The students are informed that during the term they will have multiple opportunities to try to reach the goal of writing five sentences without mistakes (i.e., grammar, spelling, capitalization, punctuation, or vocabulary). A student can only reach this goal one step or sentence at a time. After writing one sentence with no mistakes in it, he can then try to write two perfect sentences. When he has written two sentences with no mistakes, he tries to write three, and so on until he has written five sentences. For each level the student completes, he receives one or two credits toward his final grade. It is not as easy as it sounds. Each time the students try to write perfect sentences, the teacher should change the teaching point. Students complain a lot during the term when they are not allowed to progress to another level because of an error; however, they frequently ask if they are going to have an opportunity to test what they have mastered by being allowed to write sentences at the end of class. Also, they rank this activity as one of their favorites on course evaluation sheets Variation 1: Have the students keep a register of the sentences where they made mistakes and write the corresponding correction. They should also receive credit for the register if they keep it. Variation 2: In composition courses, instead of different teaching points, the teacher can have each student try to write a perfect paragraph. The first sentence the students have to write is a good topic sentence with no mistakes. When a student has written an adequate topic sentence, then he copies over the topic sentence and adds one developing sentence. A student is permitted to add another developing sentence when what he has previously written is perfect. The teacher can decide how many sentence the Perfect Paragraph has to have. World's Best Jobs! Dave's ESL Cafe Copyright © 2008 Dave Sperling. All Rights Reserved.
From the 1870s the government was New Zealand’s main provider of surveying and mapping services. Surveyors measured points and distances on the ground and staked out areas, so settlers could buy land, and accurate maps could be made. In the late 19th century, the most accurate way to survey and map the land was by first establishing a triangulation network – a network of triangles that covered the whole country. Other points could be located in relation to these. However, a major triangulation was slow and expensive. Instead the government divided the land into areas called meridional circuits. These had one known point within them, from which other surveys could be done. The great triangulation At the start of the 20th century, the government decided they needed a national triangulation network. They did a triangulation of the North Island between 1909 and 1938, and of the South Island between 1938 and 1942. Aerial photography made it much faster to map the land than surveying it on the ground. From the 1930s, the government made a series of topographical maps – maps that show the contours of the land – covering all of New Zealand. A technique called photogrammetry allowed staff to view aerial photos as if they were three-dimensional, and make accurate topographical maps. Aerial photos have distortions in them, because of the curve of the earth’s surface and the angle of the camera. Orthophotos are aerial photos with the distortions corrected. Other information such as property boundaries can also be added. Types of maps A range of different types of maps have been made in New Zealand. - Travel maps show the country’s roads – they became more important as more people owned cars. - Street maps of towns and cities were published by the government and private companies. - Atlases included school atlases, national atlases and a historical atlas. From the 1970s, satellite images of New Zealand were produced. Global positioning systems (GPS) are used to locate points on the earth in relation to satellites. Land information today In the 1980s, the government’s surveying, mapping and land information services were combined in the Department of Survey and Land Information. In 1996, this was split into two organisations – Land Information New Zealand (LINZ) and Terralink.
Nautical Archaeologists have recently discovered a Roman era shipwreck off of the coast of Albania. The wreck, which dates to the 1st century BCE was filled with amphorae used to store wine. Archaeologists believe that merchants were transporting the wine from Albania’s vineyards to be sold throughout the Mediterranean. In spite of its age and relatively shallow depth (50 m below sea level), the wreck is remarkably well preserved and nearly all of the vessel seem to be in tact. Both American and Albanian archaeologists will work together to excavate the findings and are excited about the potential for insight it provides about this period in Roman history. To read more about the wreck and its findings, see this article on MSNBC.
NCERT Solutions for Class 8th Social Science Chapter 5 When People Rebel National Council of Educational Research and Training (NCERT) Book Solutions for Class 8th Subject: Social Science Chapter: Chapter 5 When People Rebel Class 8th Social Science Chapter 5 When People Rebel NCERT Solution is given below. What was the demand of Rani Lakshmibai of Jhansi that was refused by the British? Rani Lakshmibai of Jhansi wanted the East India Company to recognise her adopted son as the heir to the kingdom after the death of her husband. This demand was refused by the British. Ultimately, the Company annexed the kingdom as per the Doctrine of Lapse. What did the British do to protect the interests of those who converted to Christianity? In 1850, a new law was passed to make conversion to Christianity easier. This law allowed an Indian who had converted to Christianity to inherit the property of his ancestors. What objections did the sepoys have to the new cartridges that they were asked to use? The new cartridges were suspected of being coated with the fat of cows and pigs. Both Hindus and Muslim sepoys were offended by the introduction of these cartridges. Their religious sentiments were affected, and this was the reason they refused to use the cartridges. They felt that the British were trying to insult their religions. How did the last Mughal emperor live the last years of his life? After the death of Aurangzeb, Mughal emperors held only symbolic value. Bahadur Shah Zafar was the last such Mughal emperor. During the 1857 revolt, the rebels needed someone who would rule the land once the British were thrown out of the country. They decided that this leader would have to be the Mughal emperor living in the Red Fort, in Delhi. Though a reluctant leader at first, Bahadur Shah did play an important role in the rebellion. Though Mughals had lost their earlier authority, a Mughal emperor’s word still held importance for quite a number of smaller rulers and chieftains. Bahadur Shah sent letters to all such chiefs and rulers, urging them to come forward and support the rebellion. After the revolt was suppressed, Bahadur Shah was tried in court and sentenced to life imprisonment. He and his wife were sent to prison in Rangoon in October 1858. He died in the Rangoon jail in November 1862. What could be the reasons for the confidence of the British rulers about their position in India before May 1857? Since the mid-eighteenth century, the power of the nawabs and rajas was on its decline. The presence of British Residents in the courts further eroded their authority and curtailed their freedom to administer their kingdoms. The various kingdoms were forced to disband their armies and enter into a subsidiary alliance with the British. The terms of the subsidiary alliance, and later, of the Doctrine of Lapse were such that the East India Company slowly but surely took control over the kingdoms one by one. From 1757 to 1857, the Company successfully annexed various Indian states, virtually unopposed, by using a variety of political, economic and diplomatic methods. It rarely had to use military power. Another reason for the confidence of the British was the decline of the Mughal dynasty. The Company, through various measures, ensured that the dynasty came to an end. The name of the Mughal king was removed from the coins minted by the Company. It was also decided upon that Bahadur Shah would be the last Mughal king and after his death, none of his descendents would be recognised as kings. The fact that apart from the Company there was no other dominant authority in the Indian subcontinent, and the belief that there was absolutely no threat to its authority together contributed to its confidence about its position in India before May 1857. This is the reason why the revolt and the threatening form it took came as a shock to the British. What impact did Bahadur Shah Zafar’s support to the rebellion have on the people and the ruling families? Though the rebels were determined to bring the East India Company’s rule in country to an end, they were faced with the question as to who would rule the land once the space of power fell vacant. The answer to this question lay in Red Fort, in Delhi. That was where the aging Mughal emperor, Bahadur Shah Zafar had been residing. After the death of Aurangzeb, the Mughal dynasty had declined and many smaller power centres had begun asserting their authority. Yet, the word of the Mughal king still held force for quite a number of ruling families. Threatened by the expansion of the British rule, many of them felt that if the Mughal emperor could rule again, they too would be able to rule their own territories once more. When the rebel forces reached Red Fort, Bahadur Shah was reluctant at first to take on the might of the British. However, he had to give in, and was thus proclaimed their leader. Having this symbolic head inspired the rebels to fight the British with renewed confidence, hope and courage. The emperor wrote letters to the various chiefs and rulers of the country to come forward and organise a confederacy of Indian states to fight the British. In consequence of this action, the rebellion spread. The leadership of the Mughal emperor seemed to provide legitimacy to it. Regiment after regiment mutinied, and joined the rebel troops at Delhi, Kanpur and Lucknow. After them, the people of various Indian towns and villages also rose up in rebellion and rallied around local leaders, zamindars and chiefs. This not only strengthened the rebel forces, but also gave a national character to the rebellion. How did the British succeed in securing the submission of the rebel landowners of Awadh? During the revolt, the defeat of the British forces in a number of battles caused a number of uprisings against the British in various Indian states. A widespread popular rebellion developed in the region of Awadh in particular. The villages took to arms and the landlords led them. After the defeat of the rebel forces, the British had a two-pronged strategy to suppress the rebels and the rebellion. On the one hand, they tried and hanged a number of rebel leaders who had challenged their authority and could do so again in the future. On the other hand, they tried their best to win back the loyalty of the people. They announced reward for loyal landowners. They were assured that they would be allowed to continue to enjoy traditional rights over their lands. Those who had rebelled were told that if they submitted to the British, and if they had not killed any white people, they would remain safe and their rights and claims to land would not be denied. In what ways did the British change their policies as a result of the rebellion of 1857? Changes in the policies of the British after the suppression of the rebellion of 1857: (i) British Crown took over the control of administration − The British Parliament passed an Act in 1859, under which, the powers of the East India Company were transferred to the British Crown. The British government was now directly responsible for ruling India. (ii) Provided a sense of security to the local rulers − The ruling chiefs of the country were assured that their territories would never be annexed by the British. However, they had to swear allegiance to the British crown. They also abolished the Doctrine of Lapse, thereby allowing rulers to pass on their kingdoms to adopted sons. (iii) Provided a sense of security to landowners − Policies were made to protect landlords and zamindars, and give them security of rights over their lands. (iv) Reorganised the army − The proportion of Indian soldiers in the army was reduced and the number of European soldiers in the army was increased. (v) Treated the Muslims with suspicion and hostility − Considering them to be responsible for the rebellion in a big way, the British confiscated the land and property of Muslims on a large scale. (vi) Promised non-interference in the sphere of religion − The British assured the people of India that their religious and social practises would be respected and not interfered with. \|« Previous\|\|Next »\|
recall that the area of a circle is given by: Area = pir^2 since in the problem, diameter is given, we first get radius: diameter = 2radius d/2 = r 15/2 = 7.5 ft = r A = pir^2 A = 3.147.5^2 A = ? now solve this using calculator,, to round off, first you need to know the place of the digit you want to round off,, in the problem it's 'to the nearest whole number (or the ones digit)'. thus we look at the number to the right of ones digit if the number to the right of ones digit is: greater than or equal to 5, you add 1 to ones digit less than 5, the ones digit does not change 342.67 --->rounding off to nearest whole number gives 343 now apply this to the answer you've got. :) hope this helps~ :) rounded to the nearest whole number Answer this Question geometry - A CIRCLE HAS AN AREA OF 50 SGUARE FEET.WHAT IS THE APPROXIMATE ... 10th grade - If a circle has a diameter of 7inches, what is the circumference ... Circumference and Area of Circles - can someone help me with these:Find the ... math - i am a decimal with my last digit in the hundredths. rounded to the ... Rounding Decimals - Use the digits 0,2,5 and 8. Write a decimal that will round ... Math - The diameter of a circle is 7 inches. What is the circumference of the ... math - I'm asked to find the circumference of a circle to the nearest tenth and ... Math - How many cubic yards of concrete will it take to fill a cylindrical ... Math - Math Problem: Find the area of a circle that has a radius of 14 feet. ... summer math hw - one circle has a diameter of 10 inches. a second circle has a ...
T-Shirts & Stuff Visit Olive-Drab.com's sister site for over 8,000 free military vehicle photos! French Indochina War At the end of World War II, the Southeast Asian land of Vietnam was a French colony, part of their Indochina Union that included Vietnam, Cambodia, and Laos. French rule was consolidated by 1883, conducted for the benefit of France with little regard for the local inhabitants. In this environment, nationalistic movements were a regular occurrence, including one in the 1920s led by a man who would later take the name Ho Chi Minh. Background to the French Indochina War 1946-1954 Ho Chi Minh went to the Soviet Union and China for training in the 1920s and 1930s and was one of the organizers of the Indochinese Communist Party in 1930. During WW II he led guerrillas against the Japanese occupation, gaining important experience in such operations. American OSS (Office of Strategic Services, a precursor to the Central Intelligence Agency) officers attempting to rescue downed American fliers behind Japanese lines encountered Ho Chi Minh. One of the OSS group, Archimedes Patti, had no illusions that Ho was anything but a dedicated Communist, but he also took very seriously the Vietnamese leader’s assertion he would not allow any other power to replace French rule. He desired American support, Ho told Patti, and conveyed a desire for American support in letters and a telegram to President Truman (see below). As the defeat of Japan loomed, in March 1945, the French attempted to resume their rule in Vietnam. The Japanese declared Vietnam independent and gave power to a puppet emperor Bao Dai. But Ho Chi Minh had already organized a movement for Vietnamese independence, known as the Vietminh (or Viet Minh). They seized Hanoi in the north, replaced Bao Dai, and declared the Democratic Republic of Vietnam on 2 September 1945, the day the Japanese surrendered in Tokyo. But the British and Chinese were given control of Vietnam by the victorious Allies and in 1946 the British ceded control of the south back to the French, based in Saigon. The Vietminh government under Ho remained in control of only portions of the north, as the French resumed control. Ho Chi Minh negotiated with the French and reached an agreement under which his independent Vietnam would be recognized, as part of the French union of colonies, but the French would get to keep 25,000 troops in the north until 1951. Ho accepted the terms, but the French backed out. When the French attacked the northern port city of Haiphong in late November 1946 with a heavy bombardment, the French Indochina War commenced. Summary of the French Indochina War The French Indochina War, sometimes called the First Indochina War, lasted for nine years. The French Army carried out conventional war with conventional armaments against the Vietminh guerrilla. In many ways this period from 1946 to 1954 was a rehearsal for the American Vietnam War of the 1960s and 1970s, with the U.S. taking the role of the French, and repeating their errors, while Ho Chi Minh and his military commander Vo Nguyen Giap, played the same roles in both wars and were successful both times. As with the Americans later, the French had superior firepower and military technology but the Vietminh were fighting on home territory, could dominate the jungles and roads, and had a single-minded purpose shared from the top to the bottom of their society and army. The French commanders, on the other hand, had to contend with Paris politicians tuned to French public opinion. Their inflexible battle plans failed to adequately contend with the fast and furious pace of the North Vietnamese Army (NVA) that came into being to fight this war. Fatally, the French never developed the support of the people who found it far easier to trust their relatives from the North than the French who had been their colonial oppressors. Although the French established the Army of the Republic of Vietnam (ARVN) to defend Vietnam in the early 1950s, the French never had deep rooted support among the people. From 1946 through 1950, the war was primarily fought as a series of guerrilla actions by the NVA who repeatedly absorbed more massive offensives by the French. After the Communist victory in China in 1949, Ho Chi Minh began to receive significantly more support, training and supplies from China along with political recognition as the legitimate government of Vietnam. By 1950, the Vietminh were able to mount their own offensives using heavy weapons supplied by China, attacking in the Red River Delta and northeastern Tonkin, as well as French fortified areas near the border with China. The NVA opened their offensives with massive, conventional artillery bombardments, followed by human wave attacks that sustained stupendous personnel losses but gained tactical victory. The French lost outposts (some with huge losses such as the evacuation of Cao Bang), but ultimately the Gen. Giap's string of offensives failed and Vietminh losses were so high they had to call off the attacks in 1951. A French offensive around Hoa Binh in 1951 ended with French withdrawal, after losses of about 900 French and ten times the number of Vietminh. Giap counterattacked French garrisons and drew them into repeated attempts to seize control of the war, all of which failed with high French casualties. In April 1953, the Vietminh upped the ante by invading Laos, further increasing the burdens on the French attempts to defend the region. The French countermoves attempted to draw the Vietminh into conventional battles at strong points, culminating at Dien Bien Phu, a long valley near the Laotian border. Giap destroyed the French at Dien Bien Phu by moving artillery into the surrounding hills, a position the French had discounted as impossible. While the French held out in a battle of attrition until May 1954, they lost over 7,000 soldiers there and had 11,000 taken prisoner, most of those never repatriated. By then French political will was gone and the war was lost. To formalize the facts on the ground, the Geneva Accords were signed on 20 July 1954, dividing Vietnam into north and south at the 17th parallel and establishing a 6 mile wide DMZ. Ho Chi Minh's Communist government controlled the north, while a U.S. sponsored Bao Dai government ruled in the south. The Geneva Accords called for free elections by July 1956 to determine a democratically elected government for a reunited country of Vietnam. Role of the United States in Indochina after WW II A major concern of the United States after the end of WW II was the reconstruction of Europe. Since France was dependant on income from its colonies, the U.S. backed the French as they resumed control in former colonial areas, including Vietnam. After the civil war in China ended with the Communist victory in 1949, President Truman and President Eisenhower after him could ill afford the political damage of another loss to a Communist power in Asia. In practice, the U.S. provided money, weapons and military advisors to the French while rebuffing attempts by Ho Chi Minh to approach the U.S. (See Ho Chi Minh telegram, left). After the military failure of the French in 1954, the U.S. accepted the burden of supporting the Bao Dai regime in newly formed South Vietnam and the French gave up all claim to Vietnam. President Eisenhower wrote to the new Prime Minister of the Bao Dai government, Ngo Dinh Diem, in September 1954, promising U.S. support for a non-Communist Vietnam. During the nine years of the First Indochina War, the French and their local allies counted 94,000 dead or missing while the north Vietnamese claimed 150,000 dead. Although the U.S. had contributed about $3 billion to assist the French in Indochina as a bulwark against Communist expansion, French colonial rule was at an end. But an even greater loss was built into the unworkable plan of the Geneva Accords that inevitably led to U.S. involvement in the Second Indochina War, the Vietnam War of the 1960s and 1970s. Recommended Books about the French Indochina War
Function of Cartilage Supports soft tissue, such as the C-shaped hyaline cartilage rings in the trachea Growth Patterns of Cartilage Cartilage grows in two ways: Interstitial Growth and Appositional Growth Interstitial Growth (stage 3) Cells synthesize and secrete new cartilage matrix, they are pushed apart and now reside in their own lacunae Interstitial Growth (stage4) The new individual cells within their own lacunae are called chondrocytes. new matrix has been produced internally, and thrus interstitial growth has occurred. Appositional Growth (second type of Cartilage Growth) Growth that occurs later in life after full maturity due to injury or healing. This growth occurs only at the prriphery of the tissue. Appositional Growth (stage 1) Stem cells at the internal edge of the perchondrium begin to divide, forming new and committed cells type of stem cell that can produce a subset of like cells (ex. hematapoetic cells - blood stem cells). Appostional Growth (stage 3) These chondroblasts, located at the periphery of the old cartilage, begin to produce and secrete new cartilage matrix, they are pushed apart and now reside in their own lacunae. Appositional Growth (stage 4) The new matrix has been produced peripherally, and thus appositional growth has occured. How do the three cartilage types differ with respect to their locations and functions in the body?
Update: NASA says Dawn successfully entered orbit around Vesta Land ho! After nearly four years of interplanetary travel, NASA’s Dawn spacecraft is about to be captured into orbit around the giant asteroid Vesta. Meanwhile, a new paper argues that Vesta and Ceres, another huge asteroid set to be visited by Dawn, are the main stumbling blocks to predicting the long-term fate of the solar system. At 530 kilometres across, Vesta is one of the biggest denizens of the asteroid belt, the junkyard of leftover planetary building blocks found between Mars and Jupiter. Dawn is expected to enter orbit around it at 0500 GMT on Saturday (2200 PDT on Friday). Its cameras and spectrometers will study Vesta’s topography and chemical composition. That could reveal clues about the era of early planet formation, since Vesta is thought to have finished growing long before Earth and the other planets. After a year in orbit, Dawn will head to Ceres, the solar system’s biggest asteroid. While Vesta, like Earth, is divided internally into a metallic core and an outer rocky mantle and crust, Ceres seems to contain a lot of water ice. Scientists hope data collected by Dawn will help them understand how the two large asteroids ended up so different in composition. Although Vesta and Ceres are tiny compared to Earth, they have a surprisingly large influence on our planet’s orbit. A study published this week says that because of chaotic interactions between Vesta and Ceres, astronomers will never be able to calculate Earth’s trajectory more than 60 million years in the future, or rewind it more than 60 million years in the past. Vesta and Ceres have frequent close passes with each other that change their orbits. The result is that their orbits are chaotic, changing in ways that are impossible to predict more than about 400,000 years into the future. Gravitational tugs from Vesta and Ceres in turn affect the orbits of Earth and the other planets. The effect of these small tugs build up over time, making it impossible to calculate the positions of the planets more than 60 million years forwards or backwards in time. Astronomers will more precisely measure the positions of Vesta and Ceres with the Dawn spacecraft, but this will hardly matter for long-term predictions. The chaotic interactions between Vesta and Ceres will quickly amplify even the tiniest of measurement errors, foiling any attempt to predict planet orbits beyond the 60-million year horizon, says the study’s lead author Jacques Laskar of the Observatoire de Paris, France. “[This] appears to be an absolute limit that will not be improved in the future,” he says. Journal reference: Astronomy and Astrophysics, DOI: 10.1051/0004-6361/201117504 More on these topics:
Nonpoint Source Pollution NPS pollution occurs when rainwater or snow melt carries sediment, organic materials, nutrients, or toxins into rivers, lakes, and streams. During large storms the runoff to surface water and the rate of infiltration to groundwater increases, and so does the rate of NPS pollutant movement. Almost any land use can lead to NPS pollution. The more intensive the land use, the greater the chance of pollution. NPS comes from a variety of sources in both urban and rural areas. Examples of NPS pollution include: sediment from improperly managed construction sites farmlands and eroding streambanks excess fertilizers and nutrients from croplands acids and salts from mining operations urban runoff and parking lots toxic chemicals from building sites nurseries and orchards bacteria and viruses from domestic sewage NPS affects drinking water supplies, wildlife habitat, recreational opportunities such as boating, swimming, fishing, and much more. It is the major challenge in our battle for cleaner water. Based on data from the OEPA, NPS pollution affects over 13,700 miles of Ohio’s 29,113 perennial stream miles. Twenty-nine percent of these perennial streams are classified as impaired as a result of nonpoint source pollution. NPS pollution is now the number one cause of water quality problems in Ohio. Hydromodification—-the physical alteration of a stream or river—-is the chief source of aquatic life use impairment. NPS pollution is one of the most complex environmental problems facing Ohio, and its impacts are extensive. Many government agencies are confronting this problem by developing programs aimed to correct and prevent nonpoint source pollution. However, government alone cannot solve nonpoint source pollution problems. Pollution clean-up has proven difficult and costly; therefore, pollution prevention makes sense. Because NPS is caused by people, it is people who need to take an active role in preventing it. Pollution prevention needs to become an integral part of our routine behavior. For more information on NPS visit the following site: Nonpoint Source Pollution Permits for wastewater have been required through the Clean Water Act since 1972. The USEPA began to regulate stormwater with the inception of the National Pollutant Discharge Elimination System (NPDES) Program. In 1990, NPDES Phase I was established to regulate Municipal Separate Storm Sewer Systems, Industrial Storm Water, and Construction Sites disturbing 5 acres or greater. More recently, NPDES Phase II was established in 1999. This phase added small municipalities (in urbanized areas as defined by census data) and construction activities disturbing 1 acre or greater to the list of permitted entities. Under Phase II, permitted entities must develop a Municipal Storm Water Program (MSWP) aimed at reducing the discharge of pollutants and protecting or improving existing water quality by implementing six minimum control measures. The six minimum measures are: - Public Education and Outreach - Public Involvement and Participation - Elimination of Illicit Discharges - Pollution Prevention for Municipal Operations - Construction Site Runoff Control - Post-Construction Storm Water Management.
This 68 page book, NOUN PICTURE CARDS, was created to expose young children to pictures and words that may not be familiar to them, expanding their vocabulary and knowledge of Person, Place and Thing. Teacher NOUN Vocabulary Word Wall Cards - 108 NOUN Cards - "TAKE IT TO YOUR SEAT" Activity Person, Place, Thing- Hold-up Cards for Noun Game-"What is it?" Color, Write, Draw Activities - 58 (29 sheets x 2) "TAKE IT TO YOUR SEATS" sentence paper 2 - 1st grade frames 2- 2nd grade frames UNIQUELY CHERRY'S TPT.COM ANGELA DAVIS
1) jitter is the variation in the time between packets arriving, caused by network congestion, timing drift, or route changes. A jitter buffer can be used to handle jitter. 2) Jitter is the deviation in or displacement of some aspect of the pulses in a high-frequency digital signal. As the name suggests, jitter can be thought of as shaky pulses. The deviation can be in terms of amplitude, phase timing, or the width of the signal pulse. Another definition is that it is "the period frequency displacement of the signal from its ideal location." Among the causes of jitter are electromagnetic interference (EMI) and crosstalk with other signals. Jitter can cause a display monitor to flicker; affect the ability of the processor in a personal computer to perform as intended; introduce clicks or other undesired effects in audio signals, and loss of transmitted data between network devices. The amount of allowable jitter depends greatly on the application.
Giardiasis is an intestinal illness caused by the parasite, Giardia lamblia. The parasite can be found in the stools of infected humans and animals (dogs, cats, beavers, rodents). People who drink untreated surface water from ponds, lakes and streams have a higher risk of getting giardiasis. Travelers and persons in institutional settings or day care centers where children are not toilet-trained also have a higher risk of getting giardiasis. Symptoms of giardiasis normally begin 1 to 3 weeks after becoming infected. In otherwise healthy individuals, symptoms may last 2 to 6 weeks, occasionally longer. The symptoms of giardiasis include frequent, loose, pale, greasy stools (often foul smelling), with gas, bloating, cramps, fatigue, weight loss, nausea, vomiting, and diarrhea. Fever is usually not present, and many people infected with Giardia may have no symptoms at all. You get giardiasis by eating or drinking food or water contaminated with human or animal stool containing the parasite or its eggs. The parasite is spread through person-to-person contact. It is not spread by coughing or sneezing. Giardiasis is diagnosed through a laboratory test which finds the organism, antigen, or DNA in stool, intestinal fluid, tissue samples, biopsy specimens, or other biological samples. Usually three stool samples collected more than 24 hours apart look for ova and parasites. A doctor can prescribe medicine to treat giardiasis. Often a repeat course of the same medication will be needed to get rid of the infection. Some individuals may get better on their own without treatment. The most common medications used are metronidazole, tinidazole, or nitazoxanide. If you’re asymptomatic, you do not need treatment unless you are likely to spread the disease. Being infected with giardia does not prevent you from being infected again. Giardia is found in Hawaii, mainly on Oahu. There are also cases reported from those who traveled outside of Hawaii. Reduce your exposure to contaminated food or water. - Do not drink untreated water directly from ponds, lakes, and streams. If you are not sure about the safety of drinking water, you should drink bottled water or boil tap water for at least one minute. If boiling is not possible, use a filter that has been tested and rated by National Safety Foundation (NSF) Standard 53 or NSF Standard 58 for cyst and oocyst reduction; filtered tap water will need additional treatment to kill or weaken bacteria and viruses. Chemically treating water with bleach or iodine tablets may not work as well as boiling or filtering. - Wash your hands carefully after using the toilet, and especially before making or eating food. - Wash your hands thoroughly after changing diapers and after cleaning up a pet’s waste. After diaper changing, wash the child’s hands also. - Keep children away from animal wastes. Last reviewed December 2018
Much of the concern for burrowing owls in western North America arises from their documented and suspected changes in distribution and abundance, as well as alterations of its environment, such as reductions of burrowing mammals and intensive pesticide use. These issues were recently documented in the U. S. Fish and Wildlife Service's Status Assessment and Conservation Plan. Many of these concerns are relevant in California, where large resident (breeding) and non-resident (wintering) populations exist. To better understand burrowing owl population dynamics in different habitat types, we established four intensive study areas in California in the key habitats burrowing owls occupy. We selected four habitats in which to locate demographic study sites: (1) the urban environment, (2) intensive agriculture areas that surround small habitat patches, (3) agriculture areas in which owls nest primarily along irrigation ditches and canals, and (4) large grasslands that reflect the best examples of the native open grassland habitat and landscape typical of burrowing owls in California. This study applies both an observational and experimental approach in answering questions that relate to factors affecting the dynamics of burrowing owl populations. Our primary objective is to understand factors affecting survivorship and productivity. We are using recent advances in mark-recapture methods to estimate survival rates and to evaluate and rank models that include various environmental and biological factors that are potentially responsible for differences among individuals and study sites. Marking individuals also allows us to estimate movement rates of young and adults, as well as to track the productivity of individual female owls. We are also exploring the importance of additional factors, such as individual animal characteristics, pesticide exposure, diet, and microhabitat conditions, that may affect demographic parameters. These questions are the subject of on-going graduate student projects and were recently summarized in the U.S. Fish and Wildlife Service's Status Assessment and Conservation Plan. See the Burrowing Owl in The Imperial Valley with BBC's Click on photo to see the Owl episode (Quick Time Player) Former Graduate Students: Daniel Catlin, M.S. Candidate Within- and Between-Season Breeding Dispersal of Burrowing Owls in Grassland and Agricultural Environments
Flotation is a process in Liquid-Solid Separation technology whereby solids in suspension are recovered by their attachment to gas (usually air) bubbles, usually with objective of removing the solids from the liquid. The particles most effectively removed are in the size range from 10 to 200 μm. The particle-bubble aggregates that are formed have a density less than the suspension itself; they rise to the surface and are removed. In the minerals industry, selective froth flotation is used to concentrate specific species of particles in a finely ground ore. "Flotation" is a generic term for a number of processes known as "adsorptive bubble techniques", Lemlich (1972); these are classified into foaming and nonfoaming separation methods. Foaming methods require the addition of surfactants to generate a relatively stable foam or froth which then acts as a carrier fluid during particle removal. The properties most important in determining the success of a flotation process are solid hydrophobicity, bubble to particle size ratio, and the extent of turbulence in the fluid. Most inorganic, and many organic, particles have hydrophilic surfaces, and as such they are not floatable. To attach a gas bubble to these solids therefore requires the displacement of a water film from their surfaces. This is achieved using surfactants (known as collectors) to render the particle surface hydrophobic. Collectors are usually long chain hydrocarbon molecules containing polar groups; these adsorb on to the surface at the charged group, with the hydrocarbon chain being presented to the aqueous phase. (See Surface Active Substances.) Other reagents used in flotation are frothers to promote a smaller bubble size and a more stable froth, and modifiers or conditioners to adjust the pH of the suspension and assist attachment of bubbles to specific particle species in the suspension. Conditioners used include coagulants and polymer flocculants. All flotation systems require a source of gas bubbles. In natural flotation, release of gas in the form of bubbles from, for example, a fermentation is the cause of scum at the surface of the liquid. Aided flotation is a natural flotation improved by blowing air bubbles into the suspension, and is useful for the separation of greases dispersed in a turbid liquid. In most process industry flotations, the bubbles are formed by three main techniques: (i) mechanically, using an agitator combined with an air injection system or by pumping the air through a porous plate or nozzle, to form bubbles that measure 0.2 to 2 mm in diameter (mechanical flotation or froth flotation); (ii) by gas nucleation from a solution to form bubbles of about 40 to 70 mm in diameter, induced by subjecting the suspension to a vacuum (vacuum flotation), or by saturating water with the gas under pressure and injecting it into the suspension (dissolved air flotation), or by supersaturating the suspension under pressure and then relieving the pressure (microflotation); and, (iii) by electrolysis of the aqueous phase (electroflotation) to produce bubbles < 50 μm with minimal turbulence. As general purpose liquid-solid separation technologies, the two flotation techniques which have found increasing value in recent years are dissolved air (DAF) and electroflotation (EF). EF has the advantage that no pressurized recycle is required; the flow handled by the EP unit comprises the feed only. The recycle employed with DAE increases the flow into the unit. In EF there is no need for recycle pumps, compressors or saturators, but EF does require transformer-rectifier systems which can be relatively expensive. Both DAF and EF may be used either for clarification of liquids or for thickening or concentrating of solids suspensions. Power consumptions and air flows are dependent on many factors, but comparable data (per m3 of water treated) may be given for water treatment applications: aided flotation (grease removal) requires about 5 to 10Wh m−3 and 100 to 400 Nl m−3, froth flotation 60 to 120 Wh m−3 and 10,000 Nl m−3, and DAF (clarification) 40 to 80 Wh m−3 and 15 to 50 Nl m−3. The microscopic mechanisms that occur in flotation are complex, making it impossible to describe in mathematical detail or to develop fundamental design equations. According to Fuerstenau (1976), most flotation systems with a high degree of turbulence approximate to perfect mixers and the recovery of solids is then given by: In those dissolved air flotation systems where turbulence is low and in electroflotation cells, hydrodynamic conditions are probably closer to plug flow. In practice, it is difficult to achieve plug flow conditions, and a reasonable approximation to describe recovery by flotation is: In these equations, c is the solids concentration, c0 is the solids concentration in the feed, and is the mean retention time of the suspension. Comparing the above equations shows that theoretically a plug flow flotation cell is more efficient than a perfectly mixed system (for the same k and ); to put this another way, a smaller plug flow tank will give the same recovery as a larger perfectly mixed system [Jowett and Sutherland (1979)]. Stevenson (1986) has outlined practical methods for the determination of design and scale-up data for flotation systems. (See also Foam Fractionation.) Fuerstenau, M. C., (Ed.) (1976) Flotation, A. M. Gaudin Memorial Volume. American Institute of Mining Engineers, New York. Jowett, A. and Sutherland, D. (1979) A simulation study of the effect of cell size on flotation costs, The Chemical Engineer, 603-607. Lemlich, R. (1972) Adsorptive Bubble Separation Techniques, Academic Press, London. Stevenson, D. G. (1986) Chapter 5, Solid/Liquid Separation Equipment Scale-up, (D. B. Purchas and R. J. Wakeman, Eds.). Uplands Press and Filtration Specialists, London.
Out of the Many, One In the title “United States of America,” the emphasis is necessarily on the word united. When America was in its infancy and seeking to establish itself as a sovereign nation, it faced many challenges, not the least of which was that King George of England was not interested in letting his colonies in America go free. If these colonies were to establish themselves as a nation apart from British rule, they were going to have to do so by defeating the most powerful army on the earth, namely, the British Army. To do so, it would have to pull together a formidable army out of a scattered rag-tag group of colonial militia. Yet, perhaps the most daunting task in this mission was the pulling together thirteen separate colonies and convincing them of the need to rally around a single vision and mission. This would not be easy. Each of these thirteen colonies had been established with its own sense of autonomy and the rhetoric for revolution had only fueled the autonomous spirit. Yet, the Fathers of the Revolution understood the necessity of the unity of these colonies. Therefore, Benjamin Franklin, John Adams, and Thomas Jefferson were commissioned to develop a seal around which unity in colonies could be fostered. The seal that they suggested contained the Latin phrase e pluribus unum — out of many, one.
LONDON A genetic discovery could help explain why flu makes some people seriously ill or kills them, while others seem able to bat it away with little more than a few aches, coughs and sneezes. In a study published in the journal Nature on Sunday, British and American researchers said they had found for the first time a human gene that influences how people respond to flu infections, making some people more susceptible than others. The finding helps explain why during the 2009/2010 pandemic of H1N1 or "swine flu", the vast majority of people infected had only mild symptoms, while others - many of them healthy young adults - got seriously ill and died. In future, the genetic discovery could help doctors screen patients to identify those more likely to be brought down by flu, allowing them to be selected for priority vaccination or preventative treatment during outbreaks, the researchers said. It could also help develop new vaccines or medicines against potentially more dangerous viruses such as bird flu. Paul Kellam of Britain's Sanger Institute, who co-led the study and presented the findings in a telephone briefing, said the gene, called ITFITM3, appeared to be a "crucial first line of defense" against flu. When IFITM3 was present in large quantities, the spread of the virus in lungs was hindered, he explained. But when IFITM3 levels were lower, the virus could replicate and spread more easily, causing more severe symptoms. People who carried a particular variant of IFTIM3 were far more likely to be taken into hospital when they got flu than people who carried other variants, he added. "Our research is important for people who have this variant as we predict their immune defenses could be weakened to some virus infections," Kellam said. "Ultimately as we learn more about the genetics of susceptibility to viruses, then people can take informed precautions, such as vaccination to prevent infection." MICE EXPERIMENTS HELPED MAKE BREAKTHROUGH The potential antiviral role of IFITM3 in humans was first suggested in studies conducted by Abraham Brass of the Ragon Institute and Gastrointestinal Unit of Massachusetts General Hospital in the United States. Using genetic screening, he found that it blocked the growth of flu and other viruses in cells. Teams led by Brass and Kellam then took the work further by knocking out the IFITM3 gene in mice. They found that once these animals contracted flu they had far more severe symptoms than mice with the IFITM3 gene. In effect, they said, the loss of this single gene in mice can turn a mild case of influenza into a fatal infection. The researchers then sequenced the IFITM3 genes of 53 patients who had been hospitalized with seasonal or pandemic flu and found that a higher number of them had a particular variant of IFITM3 compared to the general patient population. The researchers believe this variant results in a shorter version of the protein or one that is less abundant in cells, leaving patients more vulnerable to flu when they get it. "Our efforts suggest that individuals and populations with less IFITM3 activity may be at increased risk during a pandemic, and that IFITM3 could be vital for defending human populations against other viruses such as avian influenza," said Brass. (Reporting by Kate Kelland; Editing by Andrew Osborn)
In June 1852 Margaret Douglass, a white woman and former slaveholder, began a school for free black children, which she operated out of her home in Norfolk, Virginia. The school opened with an enrollment of twenty-five boys and girls. On the morning of May 9, 1853, eleven months after starting the school, Douglass was arrested for violating a Virginia law that made it illegal to assemble any African Americans, free or enslaved, for the purpose of instructing them to read or write. Douglass pleaded ignorance of the law, having understood that the regulation applied to enslaved blacks only. For this reason, Douglass was careful to enroll only free blacks at her school. Although the mayor of Norfolk seems to have dismissed Douglass' case, the local grand jury indicted her in November 1853, and she was convicted and fined one dollar. Acting in her own defense, Douglass insisted that she was not an abolitionist, that she approved of the institution of slavery, that she had only tutored free blacks at her school, and that her students also attended a white-run Sunday school, at which they received books and instruction in reading and writing. When Douglass returned to court to receive her sentence on January 10, 1854, the judge required her to serve a one-month prison sentence “as an example to all others in like cases.” Following Nat Turner's Rebellion in 1831, the General Assembly passed several new laws to restrict the freedom of enslaved and free black Virginians, including an early version of the law under which Douglass was convicted. Because many white Virginians believed that Turner's literacy and his role as a preacher contributed to his rebellion, they made it illegal for black ministers to preach and required white clergymen to superintend black religious services. Although they did not make it illegal for white people to teach black people to read and write, they did make it illegal to assemble enslaved and free blacks for that purpose. Abolitionist literature printed in the North began to appear in Virginia about that same time, reinforcing apprehensions among slave owners that gatherings of literate African Americans, even if under white supervision, posed a threat to public safety. By the early years of the nineteenth century most African Americans in Virginia had been converted to Protestant Christianity, and many of them regularly attended church services. White Virginians held contradictory opinions about whether the spiritual advantages to black Virginians of being able to read the Bible outweighed the dangers that literacy would make enslaved people ambitious for freedom. Nevertheless, a great many Virginians, especially women, undertook to teach their own slaves to read and write, and others readily taught in Sunday schools where they emphasized the responsibility of servants to obey their masters and mistresses and to accept the status in life into which they were born. Enslaved and free African Americans often prized literacy as a precious gift that enabled them to live better lives and to read their own Bibles. A southerner and former slaveholder, Douglass was an unlikely martyr to the cause of African American education. Instructing children, sometimes including black children, was the responsibility of white middle- and upper-class women in nineteenth-century society. Douglass's refusal to remain silent after her arrest forced her to depart from her proper role of a lady in southern society. Under attack, Douglass fought for her innocence and her desire to enlighten all children's minds with Christian principles. 1. Why was Margaret Douglass arrested? 2. For how long was she imprisoned? 1. Why did white people in the nineteenth century seek to prevent African Americans from seeking educations? What were their fears? What historical incidents involving literate slaves fueled their fears? Douglass, Margaret. Educational Laws of Virginia: The Personal Narrative of Mrs. Margaret Douglass. Boston: J. P. Jewitt & Co., 1854. Foner, Philip S., and Josephine F. Pacheco. Three Who Dared: Prudence Crandall, Margaret Douglass, Myrtilla Miner—Champions of Antebellum Black Education. Westport, Conn.: Greenwood, 1984. Cornelius, Janet Duitsman. "When I Can Read My Title Clear": Literacy, Slavery, and Religion in the Antebellum South. Columbia: University of South Carolina Press, 1991. King, Wilma. Stolen Childhood: Slave Youth in Nineteenth-Century America. Bloomington: Indiana University Press, 1995.
Using hand gestures may be important for more than just making a point; they could help children to learn. In research published in the journal Developmental Psychology, preschoolers and kindergartners who naturally gestured to indicate what they were trying to do showed more self control, an ability associated with cognitive maturity. The scientists came to this conclusion after testing children for their ability to sort objects according to changing criteria. Even adults have difficulty switching from one set of instructions to another, since the brain automates some aspects of learning to optimize efficiency. Once something is learned, however, it’s a challenge to unlearn and inhibit the reflexive response. That’s why it helps to develop good habits early — whether it’s a golf swing or eating a healthy diet. It’s easier to learn something correctly the first time than it is to unlearn ineffective techniques and relearn better ones. In the experiment, 41 kids aged 2 to 6 had to place cards in trays. In one round, the tots first had to sort pictures of blue rabbits or red boats by color and then were asked to sort them by the object’s shape, regardless of color. In another game, they had to distinguish pictures of large or small yellow bears either by size or by whether teddy was right side up or sideways. During the task, some of the children instinctively used gestures — making rabbit ears when they knew shape mattered, or moving their palms from facing up to turning sideways when they were sorting by the teddy bear’s orientation — to guide themselves. “Our study shows that young children’s gesturing can help them think,” says the study’s lead author Patricia Miller, professor of psychology at San Francisco State University. What’s more, she found that this effect had a stronger effect on successful performance than age — a powerful finding given that children’s skills improve rapidly with age during this stage of development. “It’s not just what’s going on inside the head that’s linked with how kids learn and perform, but how they express it with their body that matters, too.” says Sian Beilock, professor of psychology at the University of Chicago and author of Choke: What the Secrets of the Brain Reveal about Getting It Right When You Have To, who was not associated with the study. The toddlers’ gestures could be interpreted as a glimpse of their brains at work, as they figure out how to exert the cognitive control necessary to complete their tasks. But were the gestures simply a marker for a higher level of intelligence? To find out, Miller and her team asked the toddlers to explain what they were doing, an ability strongly tied to verbal skills. It turned out that the children’s ability to correctly verbalize their reasoning did not predict their success as well as gesturing did. Gestures also increased in the few tasks just after the criteria shifted, making them more difficult, which also supports the idea that gesturing itself was helpful. The research is only the latest to explore how movement of the body is fundamental to the way in which the mind works. Earlier work showed that older children were better able to learn math if taught to use gestures while doing so. And they often found the right answer physically — for example, by making movements to signify the numbers that needed to be kept together to add correctly — before finding it verbally. Miller’s own research found improvements in math performance, which requires improved mental control, among overweight kids after they became more physically active. That has implications for improving the way we communicate and think, and could help to address developmental disorders associated with cognitive control issues, such as autism. “In some ways, motor behavior might be ahead of our conscious verbal behavior,” says Miller, “It may be pulling development along.” If that’s true, using gestures to improve self-control could also help to manage addictive behaviors. One study found that simply teaching people to inhibit actions (in this case, refraining from pressing a computer key that they were previously trained to press) before seeing images related to gambling reduced the number of risky bets they placed. Another study found a 30% drop in drinking among Dutch students who hadn’t even been trying to cut down, after they performed a task in which they restrained themselves from pressing keys when seeing images of beer. These findings suggest that simply making gestures involved with refusing or controlling behavior could help to change it. (The same process may enhance behaviors as well; heavy marijuana users who pulled images of pot “closer” to them on a computer screen smoked more following the exercise.) “There’s a close connection between mind and body,” Miller says. Abstract thought, in fact, typically requires grounding in concrete, physical metaphors. “This research suggests that not only do our thoughts affect our bodies, but our bodies can affect how we decide, what we think and how we learn,” says Beilock. So when it comes to learning, children may need to use their hands as well as their brains.
A Storytelling Festival Language Arts Activity This activity encourages students to explore the native cultures of the Americas, to learn some aspects of oral storytelling, and to share their knowledge with others. WHAT YOU NEED Examples of legends or folktales from the cultures of peoples native to the Americas WHAT TO DO - Introduce students to legends and folktales of native American cultures by reading one to the class. If possible, choose a story that explains some aspect of the culture, such as the origin of a custom, or of the environment, like the existence of a mountain range. - Explain that many of these stories were created by storytellers, who passed them on to others orally, not in writing. Only later were they written down. Tell students that they are going to become oral storytellers themselves. They will chose a story to learn and then present the story as part of a storytelling festival. - Divide students into storytelling teams or, if you prefer, have them form their own groups. Give students time to do research and to choose a story. Tell students that their story should say something important about the culture from which it comes. Remind students that their stories will be performed and that they might want to choose a story that lends itself to a dramatic reading or presentation. (Note: You might want to review the groups' choices.) - The group should study the story and make a plan for how they would like to perform, or "tell," it. For example, students may want to assign different parts of the story to each group member or have one group member act out a part or play an instrument, etc. The group should know the beginning, middle, and end of its story. - Encourage students to be creative about their presentations. Some students may want to add music and props, some may be able to incorporate costumes or rhythmic movements. - Allow enough rehearsal time for each group. Hold the first performances in the classroom. Then discuss with students how to share the storytelling with other classes, or with family and community members. Tape the presentations and make them available in the school library. You might also share the tape with a class in another community that is studying the same, or a related, theme. If student enthusiasm stays high, suggest that students share their stories with the community by presenting it at local nursing home, hospital, or the like. Encourage students to think of a landform or custom in their region and to write a "folktale" about it. Activity Search \| Reading Center \| Math Center \| Social Studies Center Education Place \| You may download, print and make copies of this page for use in your classroom, provided that you include the copyright notice shown below on all such copies. Copyright © 1997 Houghton Mifflin Company. All Rights Reserved.
Objectives and Content The course aims at introducing periglasial processes and forms, glaciology, and glacial geological processes and forms in solid rock and loose material. Glacial erosion and deposition forms and effects glaciers and ice sheets have, and have had, on the formation of the landscape, such as mountains, valleys and fjords are the central themes of the subject. The aim is also that the students should be able to describe and classify the most important glacial deposition types and that the students should be able to prepare a Quaternary geological map with an associated field report. The course starts with a 5-days field course at Finse, where deposits from glaciers and glacier forelands are studied and mapped. The lectures begin with an introduction to glaciers, mass balance, glacier motion and glacier hydrology. Furthermore, glacier erosion and deposition forms and effects that glaciers and landslides have and have had on the formation of the landscape, such as mountains, valleys and fjords are presented. A short overview is given on other Quaternary land forms resulting from chemical and physical weathering, avalanches and rivers. Genesis and classification of the major glacial deposition types are reviewed. The description and interpretation of the sea level changes during and subsequent to the last ice age is also included in the subject. The glacial process of the Scandinavian ice sheet is presented, emphasizing the course of deglaciation towards the end of the last ice age in Norway. The teaching includes three exercises in interpreting aerial photographs of glaciated landscapes, as well as an exercise in the construction of strandlines and shorelines. On completion of the course the student should have the following learning outcomes defined in terms of knowledge, skills and general competence: The student can - explain key glaciological terms and definitions - explain small scale erosion and deposition forms - explain how glacial landscapes are formed - explain the genesis and classification of glacial deposition forms The student can - make independent field observations - recognise geological processes and glacial geological erosion and accumulation forms - describe and interpret glacial erosion and deposition forms in the field - write individual field diary - prepare and report field data in writing and display data graphically - justify interpretations - prepare a Quaternary geological map - interpret graphs and figures - conduct searches for relevant literature as well as refer to literature and set up reference/literature list The student can - use a precise geological language for describing and discussing geological processes and events - recognize, evaluate and communicate humanity's role in, our independence of, and impact on the geosystem - demonstrate ability to function individually and ethically together with fellow students - conduct fieldwork on excursions in accordance with GEO/UiB's HSE guidelines Access to the Course Access to the course requires admission to a programme of study at The Faculty of Mathematics and Natural Sciences. Compulsory Assignments and Attendance Compulsory assignments are valid for 2 subsequent semesters. Forms of Assessment The forms of assessment are: Written examination, 4 hours. Examination Support Material The grading scale used is A to F. Grade A is the highest passing grade in the grading scale, grade F is a fail. Examination both spring semester and autumn semester. In semesters without teaching the examination will be arranged at the beginning of the semester. The reading list will be available within June 1st for the autumn semester and Deecember 1st for the spring semester. The course will be evaluated by the students in accordance with the quality assurance system at UiB and the department. The Programme Committee is responsible for the content, structure and quality of the study programme and courses. The course coordinator and administrative contact person can be found on Mitt UiB, or you may contact [email protected] The Faculty for Mathematics and Natural Sciences, Department of Earth Science has the administrative responsibility for the course and program The student coordinator can be contacted here: Tlf 55 58 35 19 For written exams, please note that the start time may change from 09:00 to 15:00 or vice versa until 14 days prior to the exam. The exam location will be published 14 days prior to the exam. Type of assessment: Written examination - 07.12.2018, 09:00 - 4 hours - Withdrawal deadline
Diamonds And Dust For Better Cement Structural studies at Berkeley Lab’s Advanced Light Source could point to reduced carbon emissions and stronger cements It’s no surprise that humans the world over use more water, by volume, than any other material. But in second place, at over 17 billion tons consumed each year, comes concrete made with Portland cement. Portland cement provides the essential binder for strong, versatile concrete; its basic materials are found in many places around the globe; and, at about $100 a ton, it’s relatively cheap. Making it, however, releases massive amounts of carbon dioxide, accounting for more than five percent of the total CO2 emissions from human activity. “Portland cement is the most important building material in the world,” says Paulo Monteiro, a professor of civil and environmental engineering at the University of California at Berkeley, “but if we are going to find ways to use it more efficiently – or just as important, search for practical alternatives – we need a full understanding of its structure on the nanoscale.” To this end Monteiro has teamed with researchers at the U.S. Department of Energy’s Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. Most recently, at ALS beamline 12.2.2, Monteiro and his colleagues gradually squeezed specks of fine dust of the mineral tobermorite between faces of two diamonds in a diamond anvil cell, until they achieved pressures like those 100 miles below the surface of Earth. This was the first experiment to determine tobermorite’s bulk modulus – its “stiffness” – from diffraction patterns obtained by sending a bright beam of x rays through the sample, revealing how its structure changed as the pressure increased. The results, which will appear in Cement and Concrete Research and are now available online to subscribers, led to new insights into calcium-silicate-hydrate (C S H), the material primarily responsible for the strength and durability of concrete made with Portland cement. Cement on the nanoscale Portland cement is made by baking limestone (calcium carbonate) and clay (silicates) in a kiln at over 1400 degrees Celsius to make “clinker,” which is then ground to a powder. When the powder is mixed with water, calcium-silicate-hydrate (C-S-H) is formed, which, although poorly crystallized, is a binder critical to the strength and durability of the cement paste. “We and many other groups have developed sophisticated computer models to understand the crystal structure and mechanical behavior of C S H, based on observations of how it performs,” says Monteiro. “But we’re the only group that uses minerals to validate the results of our models with experimental results.” Despite the many studies and vast literature on cements and their components, the atomic scale structure of C-S-H, owing to its high complexity, is still imperfectly known. While the mineral tobermorite, a calcium silicate hydrate named for a quaint village on the Scottish Isle of Mull, is far less common than the makings of Portland cement, one of its structures, designated 14Å tobermorite, is a perfect stand in for C-S-H in nanoscale studies. The studies were performed at beamline 12.2.2, the California High-Pressure Science Observatory (Calipso), which is supported by the National Science Foundation. Calipso is equipped with a choice of diamond anvil cells, arranged so the x-ray beam passes through the diamonds and the sample chamber between them. The diffracted x-rays fall on a CCD detector, and the diffraction patterns can be used to determine the structure of the material in the cells. The tiny sample of tobermorite that Monteiro’s team used at the ALS originally came from Southern California and was obtained from the Los Angeles County Museum. The researchers ground it to a fine powder and suspended it in liquid so that the diamond anvil cell would apply even hydrostatic pressure to every grain in the sample chamber – an opening in a metal gasket only 180 millionths of a meter in diameter. “While it’s possible to do x-ray diffraction with diamond anvil cells on a laboratory bench,” says ALS beamline scientist Simon Clark, a co-author of the research, “you can’t deal with samples this small without the brightness of a synchrotron light source. Even if you could, what takes eight hours in the lab we can do in half a minute – although we usually take at least a minute so the researchers can write everything down in their notebooks.” Putting on the squeeze As the experiments proceeded, the flattened points of the cell’s two diamonds were slowly tightened, concentrating pressure on the gasket and the contents of the sample chamber. The x-ray diffraction patterns revealed any changes in the arrangement of atoms in the crystal structure. Says Monteiro, “The diffraction patterns give us the lattice parameters of the tobermorite structure.” Lattice parameters allow the volume of the unit cells, the material’s fundamental atomic arrangements, to be calculated in three directions. “We watch how the lattice parameters change as the pressure changes, using them as a strain gauge. By knowing the applied pressure in the anvil cell, we can compute the bulk modulus.” In C-S-H the calcium, silicon, and oxygen atoms are arranged in a stack of flat layers. Highly structured layers of calcium and oxygen atoms alternate with “interlayers” of silicon, oxygen, calcium, and water molecules. In the plane of the layers (the a and b directions of the lattice parameters), tobermorite is very stiff indeed, changing very little as pressure increases. Perpendicular to the plane, along the c-axis, tobermorite is more compressible, but not by much. Even in the c direction, pure tobermorite is stiffer than a synthetic version of C-S-H the Monteiro team also tested, and to which they compared it. The calcium-oxygen layers in the synthetic C-S-H were similar to those in the tobermorite, so when altered silicon chains were deliberately introduced into the synthetic in order to mimic the disorder of natural C S H, it still retained its stiffness in the a-b plane. But along the c-axis, the disordered synthetic C-S-H grew significantly more squeezable. “It’s the interlayers that compress, and only along the c-axis,” says Monteiro. “Differences in interlayer spacing, degrees of disorder in the silicon chains, additional calcium ions, and water molecules all make the bulk modulus of the two materials virtually the same in the a-b plane, but different along the c axis. The discovery suggests a number of possibilities for improving the performance of cement – for example, one might introduce special polymers into the C-S-H interlayers to shape its behavior. This will certainly be an area for our future research.” On the Net:
Washington:When it comes to memory formation, expectation may be essential, according to a recent study. Penn State psychologists tested 60 participants and noted that the theory that links memory encoding to expectations of future relevance may better explain how human memory works. Modern psychology posits two major theories to explain the mechanisms of how memories are formed. The first is object-based encoding, storing all information about an object in working memory. The second is feature-based encoding, selectively remembering aspects of an object. For example, if you watch a group of people playing basketball, under object-based encoding theory, the brain remembers all aspects of the ball. In feature-based encoding, the brain remembers that it saw a ball, but may have no recollection of the color if the color of the ball is an unnecessary feature according to the task at hand. The proposed theory, expectancy-based binding, suggests that subjects can remember features presented in a visual scene or movie without necessarily remembering which object went with which feature when it is not necessary to do so. Researcher Brad Wyble said that the key discovery was that attending an object for an extended period of time does not ensure that all of the features of that object will be correctly associated with it in memory. Wyble added that attention is not enough to ensure accurate memory. One needs some kind of expectation that attributing certain features to the object is important. To ensure the results were robust, their entire experiment was repeated a second time with a new group of participants. The study appears in the journal Cognition. (ANI)
Elementary and Middle School (K-8) Activity Browse Grade Levelshowing only Informal Show all Grade Level Results 1 - 5 of 5 matches Discovering Plate Boundaries part of NAGT:Teaching Resources:Teaching Materials Collection Students work collaboratively using data maps to discover plate tectonic boundary processes. Data sets used are earthquakes, volcanos, seafloor age, and topography. Rainwater Harvesting Service Learning Project part of Cutting Edge:Service Learning:Activities Students will gain an understanding of the history, benefits, and components of a rainwater harvesting system and partner with community members to design and build a rainwater harvesting system for their school. Geology of Westchester County, NY part of NAGT:Teaching Resources:Teaching in the Field:Field Trip Collection Geology of Westchester County, NY Thomas McGuire Cave Creek Digital, Cave Creek, AZ Intended Audience: These trips would be appropriate for students in grades 7-12, introductory college students, teachers and the ... Celebration of Earth and Arbor Day part of NAGT:Teaching Resources:Teaching in the Field:Field Trip Collection During this trip, students will plants 25 oak trees in a designated area set by Little Rock Parks and Recreation. Implementing A Constructivist Teaching Model For Conceptualizing Geologic Time part of Rates and Time:GSA Activity Posters The activity fosters middle learning students critical thinking and allows for student generated essential questions to further their understanding of Earth's history and geologic time.
A World ApartBut the cave is not totally silent. Meiman says subtle sounds, colors and weather patterns fill the cave, especially at the lowest levels, over 300 feet below the surface, where water wears at the limestone. “It makes you more aware of light, sound, shadows,” Meiman says. Winds like the one that greeted McCombs on his first visit often billow through the tunnels. Explorers can use these cave breezes to learn about what lies ahead, something McCombs wrote about in his poem, Cave Wind: “knowing/ its speed portends the cave we'll discover, whether we will/ walk or crawl, the breadth/ of its breath, its given.” As Art Palmer, a hydrology professor at State University of New York-Oneonta who has studied Mammoth Cave for over 30 years, points out — if you are in a cave tunnel with air blasting through it, you know it goes somewhere. Breezes can form as cool air settles to the bottom of connected cave tunnels. This causes air to shift throughout the cave network. Local storms also lead to pressure changes at the surface that can create breezes within the cave. Like many caves, Mammoth cave stays at a pretty constant 53 degrees Fahrenheit, and is extremely humid. When a heavy summer rain brings a rush of warm water into the cave, the moist cave air condenses and an eerie fog forms in cave tunnels near the underground river and cave openings. During such fogs, Meiman imagines the early explorers in the cave, not understanding why fog had suddenly clouded their lantern light. Floods bring more than just fog. The cave environment is very low in nutrients, explains Tom Poulson, a biology professor from the University of Illinois. Occasional large floods renew the organic matter that feeds crustaceans and plankton, which in turn feed larger cave species like blind cave fish. “Cave creatures live slow, live long, and reproduce seldomly,” Bill Pearson, a biology professor at the University of Louisville, Kentucky says. They also have enhanced senses to maneuver in the dark. Cave crayfish live well over 100 years, while their counterparts on the surface live only 10. Pearson says the often illusive, nearly colorless cave fish standout against the darkness of the cave when a beam of light catches them. “Touched,/ they said, fish with no eyes! until I sloshed/ a pailful into light, reveled in their silence,” McCombs writes of these creatures in Bottomless Pit. Cave Connection The cave’s presence alters the surrounding landscape as well. Water doesn’t typically flow in streams on the surface, but seeps underground through sinkholes, or bowl shaped depressions, Meiman says. The landscape beyond the sandstone cap is riddled with sinkholes that feed water down into the cave. Sinkholes often plug up, and form ponds that can cover an acre or two of land, Palmer says. Heavy rains can shift the soil that plugs the bottom of these ponds, opening the sinkholes again, and causing these ponds to disappear overnight, as McCombs describes in his poem Ponds. “In Caveland, every pond's a fluke./ Let them be brief, then, as the land/ gives up the ghost of fog, morning.” “We take it for granted here that the land is unstable,” McCombs says, “it never lets you forget it is combed by a vast network of cave.”
Science is a progressive act. This means that progress in science is a tedious process that requires diligent efforts with respect to record keeping because in the case of every scientist, figuring out everything about a field of study, such as any given sub-niche of chemistry, is impossible, even in a lifetime. Record keeping is of utmost importance and accurate record keeping can and will make the difference between work that is successfully continued by a scientist's successors and work that is not successfully continued. In the field of science, all of us stand on the shoulders of giants. In other words, we all learn from our predecessors and build on what they have taught us. However, we are able to learn only from those who have successfully transcribed their knowledge in an accurate and concise fashion so as to facilitate the propagation of the knowledge to those who follow. Accurate lab notes are a must. Accurate lab notes will have a variety of properties including but not limited to: An accurate introductory description of the process or processes being studied. For the information following the introduction to be understood in it's proper context, an accurate introductory description has to be described clearly. Why is this subject of interest? What is the current understanding of the subject and why does it need to be studied further? What questions need to be answered before true progress can be made? All of these question should be covered in the introduction. Clear and concise methodology. The work that is performed or is to be performed must be clearly spelled out for those reading the notes to understand the important steps to be taken to repeat and confirm the results. Each step must be labeled in detail and must be done so in a way that can be repeated using the notes alone. This is important if results are to be duplicated. Well documented and understandable results. The results that are discovered by the initial experimenter should also be spelled out in clear detail as they may differ from the results obtained by those following them and trying to repeat their work. If results differ, this should be clearly noted by the scientists attempting to repeat the work and differences in results should also be clearly noted. Objective conclusions. Conclusions should be recorded and based on evidence and results obtained. If data or results have discrepancies, these should be noted and discussed in the conclusion.
Is it OK for children to count on their fingers? Generations of pupils have been discouraged by their teachers from using their hands when learning maths. But a new research article, published in Frontiers in Education shows using fingers may be a much more important part of maths learning than previously thought. The article, by Professor Tim Jay of Sheffield Hallam University and independent researcher Dr Julie Betenson, confirms what parents have long felt instinctively – that the sorts of finger games children often play at home are central to their education. The researchers worked with 137 primary pupils aged between six and seven. All the children were given different combinations of counting and number games to play – but only some were given exercises which involved finger-training. Some pupils played games involving number symbols, such as dominoes, shut-the-box, or snakes and ladders. Other pupils were asked to play finger games: such being asked to hold up a given number of fingers, or numbering fingers from 1–5 and then having to match one of them by touching it against the corresponding finger on the other hand, or tracing coloured lines using a particular finger. Both these groups did a little better in maths tests than a third group of pupils who had simply had ‘business as usual’ with their teachers. But the group which did both the counting and the finger games fared significantly better. “This study provides evidence that fingers provide children with a ‘bridge’ between different representations of numbers, which can be verbal, written or symbolic. Combined finger training and number games could be a useful tool for teachers to support children’s understanding of numbers,” Professor Jay said.
Pools of warm water known as Kelvin waves can be seen traveling eastward along the equator (black line) in this Sept. 17, 2009, image from the NASA/French Space Agency Ocean Surface Topography Mission/Jason-2 satellite. El Niņos form when trade winds in the equatorial western Pacific relax over a period of months, sending Kelvin waves eastward across the Pacific like a conveyor belt. Since May 2009, the tropical Pacific Ocean has switched from a cool pattern of ocean circulation known as La Niņa to her warmer sibling, El Niņo. This cyclical warming of the ocean waters in the central and eastern tropical Pacific generally occurs every three to seven years and is linked with changes in the strength of the trade winds. El Niņo can affect weather worldwide, including the Atlantic hurricane season, Asian monsoon season and northern hemisphere winter storm season. But while scientists agree that El Niņo is back, there's less consensus about its future strength. One of the characteristics that signal a developing El Niņo is a change in average sea surface height compared to normal sea level. The NASA/French Space Agency Jason-1 and Ocean Surface Topography Mission/Jason-2 satellites continuously observe these changes in average sea surface height, producing near-global maps of the ocean's surface topography every 10 days. Recent data on sea-level height from the Jason-1 and Ocean Surface Topography Mission/Jason-2 satellites show that most of the equatorial Pacific is near normal (depicted here as green). The exceptions are the central and eastern equatorial Pacific, which are exhibiting areas of higher-than-normal sea surface heights (warmer-than-normal sea-surface temperatures) at 180 and 110 degrees west longitude. This Jason-2 image reflects a 10-day data cycle centered around September 17, 2009. It shows a series of warm "bumps" visible along the equator, denoted by a black line. Known as Kelvin waves, these pools of warm water were triggered when the normally westward-blowing trade winds weakened in late July and again in early September, sending them sliding eastward from the western Pacific toward the Americas. The Kelvin waves are 5 to 10 centimeters (2 to 4 inches) high, a few hundred kilometers wide and a few degrees warmer than surrounding waters. Traveling east at about 3 meters per second (6 miles per hour), they are expected to reach the coast of Peru in October. (An animation of the evolution of Pacific Ocean conditions since January 2006 is at: http://www.jpl.nasa.gov/videos/earth/elnino20090928.mov).
In this course, we cannot offer a complete study of the logical universal and its implications. We limit ourselves to analyzing briefly the various instances which correspond to the makeup of the universal. A text of St Thomas will set us on our way: When one says ‘a thing which is actually being understood’ (intellectum in actu), there are two things implied, viz., (a) the thing which is being understood and (b) the fact that it is being understood. Similarly, when one says ‘the abstracted universal’, there are two things implied, viz., (a) the nature itself of the thing and (b) its abstractness or universality. Therefore, the nature which happens to be understood intellectively (or to be abstracted or to be an intention of universality) does not itself exist except in singular things; but its being understood (or being abstracted or being an intention of universality) exists in the intellect. We can see this by a comparison with a sensory power. For the power of sight sees the color of the apple without seeing its smell. Therefore, if someone asked where the color is that is seen without the smell, it is obvious that the color which is seen exists only in the apple; however, the fact that it is perceived without its smell happens to it because of the power of sight, since in the power of sight there exists a likeness of its color but not of its smell. Similarly, the human-ness (humanitas) that is understood intellectively exists only in this or that man; but the fact that human-ness is apprehended without individual conditions—i.e., the fact that human-ness is abstracted, and that an intention of universality follows upon it—happens to human-ness insofar as it is perceived by the intellect, in which there is a likeness of the nature of the species without a likeness of the individual principles. I, 85, 2, 2m cum dicitur intellectum in actu, duo importantur: scilicet res quæ intelligitur, et hoc quod est ipsum intelligi. Et similiter cum dicitur universale abstractum, duo intelliguntur: scilicet ipsa natura rei, et abstractio seu universalitas. Ipsa igitur natura cui accidit vel intelligi vel abstrahi, vel intentio universalitatis, non est nisi in singularibus; sed hoc ipsum quod est intelligi vel abstrahi, vel intentioni universalitatis, est in intellectu. Et hoc possumus videre per simile in sensu. Visus enim videt colorem pomi sine eius odore. Si ergo quæratur ubi sit color qui videtur sine odore, manifestum est quod color qui videtur, non est nisi in pomo; sed quod sit sine odore perceptus, hoc accidit ei ex parte visus, inquantum in visu est similitudo coloris et non odoris. Similiter humanitas quæ intelligitur, non est nisi in hoc vel in illo homine: sed quod humanitas apprehendatur sine individualibus conditionibus, quod est ipsam abstrahi, ad quod sequitur intentio universalitatis, accidit humanitatis secundum quod percipitur ab intellectu, in quo est similitudo naturæ speciei, et non individualium principiorum . I, 85, 2, 2m
While not toxic, the presence of iron in household water can lead to unpleasant odors, stained laundry, discolored water basins and even clogged pipes. However, these symptoms can also be caused by non-ferrous/ferric minerals. To measure the total amount of iron in water, you can use a color-changing test strip kit to detect the levels of iron ions in the water. The test strips are coated with the compound 2,2'-bipyridine, which forms a dark, highly visible complex molecule with the Fe(II). Prior to the test, ascorbic acid is added to the water sample, which reduces any Fe(III) ions in the water to a Fe(II) state. Use the pipette to transfer 10 milliliters of the water you want to test into the graduated cylinder. Add 1/4 teaspoon of ascorbic acid crystals to the water inside the graduated cylinder. Stir the water with the pipette to help dissolve the crystals. Dip an iron-testing strip into the water in the graduated cylinder, submerging it for about 1 second. Gently shake off any excess water and lay the test strip on a sterile dry surface and allow it to dry. After 10 seconds, the strip will have undergone its color change. Compare the color of the test strip to the different shades on the color chart included in the main test strip container. The number below the matching color square represents the concentration of iron ions in the water sample, in milligrams per liter (mg/L) or parts per million (ppm). The standard limit for iron in drinking water is 0.3 mg/L, which is very high but not dangerous. At this level, the water has a distinctly unpleasant taste, a bad odor and household appliances tend to become significantly stained with reddish or brown scale. Most household levels don't approach 0.3 mg/L, but it is not unheard of.
\|Catalog #: 020-03-0005\| \|Parent Exhibit: Eyes on Earth\| \|Description: This two-sided banner shows ten images of the planet, each created using data from a different satellite sensor. Most satellite sensors collect data by measuring different wavelengths of light. For example, the MODIS sensor on the Terra satellite can measure long wave infrared radiation. This information allows scientists to create global temperature maps of the oceans and lands. The TOPEX/Poseidon satellite, in contrast, used radar to measure ocean surface heights. This data can also be used to calculate ocean temperatures. For the large “Blue Marble” image, cloud, land, and ocean data were collected by three different satellites: the Geostationary Operational Environmental Satellite (GOES), the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite, and NOAA's Polar Orbiting Environmental Satellite (POES). In the image a powerful hurricane is visible in the Eastern Pacific, just below Baja California. Key message: Satellites give us a new perspective of our planet. Student Challenge: Study the large image of the Earth. What interesting features can you find? Do you see a hurricane?\| \|Approximate Component Dimensions: H 98 inches \| W 168 inches \| D 20 inches\| Power Required: No Powered From: N/A Give us a call or send us an email.
In the past couple of decades, the global agricultural industry has seen a massive boom, in part due to a combination of fertilizers, pesticides, herbicides, smart management techniques, mechanization, irrigation, and optimized seed varieties and genetic engineering. This jump in agriculture not only provides the opportunity to feed our growing population, but to also create ethanol and biodiesel to meet our energy demands. Johnston et al. (2011) looked at the magnitude and spatial variation of new agricultural production potential from closing of ‘yield gaps’ for 20 major ethanol and biodiesel crops. By using data sets of annual crop yields to determine the amount of additional biofuel produced from obtaining yield gaps up to the global median yield, the researchers deduced that approximately 112.5 billion liters of ethanol and 8.5 billion liters of biodiesel could be made. While this shows an optimistic future for energy security, it also has a profound effect on policymakers and how individuals will determine goals of reaching a level of biofuel use. —Anthony Li Johnston M., Licker R., Foley J., Holloway T., Mueller N. D., Barford C., Kucharik C. 2011. Closing the gap: global potential for increasing biofuel production through agricultural intensification. Environmental Research Letters 6, 034028 The authors of this paper investigated 20 common biofuel and biodiesel crops, some notable ones include maize, rice, sugarcane and wheat for biofuel, or ethanol, and soybean, rapeseed, and oil palm for biodiesel crops. The researchers obtained the M3 data set of global farming yields for these 20 crops and organized the data based on region. With information on the average global yields of crops, the authors were able to calculate the yield gaps, which they defined for this study as the “difference between current agricultural yields and future potential based on climatic and biophysical characteristics of the growing region.” They calculated the potential yields of biodiesel and ethanol if yield gaps of these crops were closed to multiple degrees, such as the global median or the 90thpercentile gap of what is completely attainable. In order to observe the effects of unequal distributions of irrigation infrastructure and sustainable water resources on crop yields, the researchers re-ran their analysis with irrigated areas excluded. In order to get a rough idea of what was needed to increase crop yield, the authors calculated the growing degree days for each crop, which is a measure of heat to predict plant development rates. The researchers found that increasing yield gaps to the median global yield would result in 112.5 billion additional liters of ethanol and 8.5 billion liters of ethanol, while obtaining the 90th percentile gap would result in 450 billion liters of additional ethanol and 33 billion liters of biodiesel. While the new tonnage varied considerably between biodiesel and ethanol, the overall percentage increase between the two were roughly equal, ranging from 10%–17%. The majority of ethanol potential identified was attributable to maize, wheat, and rice crops, while the majority of biodiesel potential was attributable to soybean, rapeseed, and oil palm. Biodiesel fuel production was generally more evenly distributed amongst its constituent crops, whereas ethanol fuel production was incredibly uneven between the crops. The implications of this study in energy security are obvious, but they also provide a benefit to policymakers or anyone setting goals for biofuel use. The research performed here shows policymakers how much additional biofuel we can expect from closing various yield gaps to different degrees, allowing them to make more accurate goals. For example, The Renewable Fuel Standard Program Final Rule of the 2007 Energy Independence and Security Act made a goal for the US to blend 36 billion gallons of biomass-based fuels by 2022. As ambitious as this goal was, this study showed that even if all the countries were to increase their biofuel crop yields to only the median level, there would still not be enough fuel to meet this goal. This study is also useful in that it shows the biofuel and biodiesel distribution based on specific crop. For ethanol, a very notable crop for fuel production was sugarcane. While this may not mean that sugarcane produces the most ethanol of any other crop per mass, if we can identify whichever crop produces more fuel than others, we can focus our biofuel industry to take advantage of these specific crops. In the face of our energy and food crisis, our nations should begin looking towards agriculture for potential solutions. Johnston et al.’s study shows how much additional biofuel can be produced by closing various yield gap levels per crop. This information will prove useful to governments seeking to implement goals of reaching certain levels of biofuel use and individuals such as farmers who want to capitalize on the most biofuel yielding crop.
In our last installment on DNA sequencing, we brought you up to speed on the Sanger method of sequencing (named after its dual-Nobel-winning inventor, Fred Sanger), which was state-of-the-art around the time of the completion of the human genome. That was about five years ago. During a visit last month to the Broad Institute, which does genome sequencing, my hosts made it clear that, while Sanger sequencing still had its uses, the action had already moved elsewhere. The Broad had recently eliminated a number of its Sanger machines, and the remainder weren't even active on the day I was there. The new technologies that are driving the old machines out to pasture rely on a range of tricks to shrink down the amount of DNA that's required for a sequencing reaction, in at least one case dropping it to a single molecule. Although the approaches they take are quite different, all of them rely on some combination of two key biochemical reactions: DNA ligation, and Polymerase Chain Reaction, or PCR. So, before we dive into the actual sequencing technology, we'll allot some time to explaining both of those. Conveniently, our initial article on DNA sequencing provided a helpful introduction. If you'll recall, sequencing a stretch of DNA required you to have a short piece of known sequence next to the part you want to sequence in order to prime the DNA polymerase and ensure it started copying in a single location. We skipped past a small issue there: most DNA sequences don't come conveniently linked to a sequence you already know. In fact, in a previously unsequenced genome, none of them do. So, how do you work around this? Most solutions involve an enzyme called DNA ligase. DNA Ligases catalyze a couple of possible reactions that share a common feature: they join loose ends of DNA molecules, normally as part of a DNA repair process in the cell. This can involve anything from patching together nicks in a fully formed double helix to linking together two unconnected strands of DNA. This turns out to be fantastic for linking known sequences onto the unknown bit you need to identify. Like just about every other enzyme that operates on DNA, ligase is fussy about the precise chemistry of the reactions it catalyzes. In the image below, there are two examples of short DNA strands with a break in the background, highlighted by the red circle. The image highlights the fact that, even though both molecules have the same exact atoms, there are two different ways a DNA strand can be broken. Ligase can only repair the break on the left, where the phosphate group is attached to what's called the 5' carbon. When given a DNA molecule like the one on the right, with the phosphate attached to the 3' carbon, nothing will happen. The reaction performed by DNA ligase simply links the phosphate to a neighboring sugar, establishing the normal DNA backbone. It can repair a nick in the backbone (or even a series of nicks), as shown here, or a complete break between two separate DNA molecules, as shown below. Now, in and of itself, this offers little opportunity to control how the DNA gets linked up. But, as we noted above, the ligase is fussy about where the phosphates are. So, by arranging your phosphates carefully, it's possible to have some control over how pieces are linked together. And, not surprisingly, there are enzymes that specifically add and remove phosphates from the ends of DNA strands. A brief but very significant aside Note the double-stranded stretch of DNA depicted above. If you'll ignore the odd distortions created by trying to squeeze a three-dimensional structure down into the 2-D realm, you'll see that, on the top strand, the 3' end of the DNA is oriented to the left. On the bottom strand, it's on the right (the 5' end is to the left). All double-stranded DNA exists in this sort of configuration, called anti-parallel. Since DNA polymerase only adds new bases to the 3' end of a DNA molecule, that means it can only copy the bottom strand by starting from a primer at the right, and moving to the left; the opposite is true if it's copying the top strand. This has important consequences, as we'll see in the next section, on PCR. Polymerase Chain Reaction So, ligase makes it possible to stick known DNA sequences on either side of the stretch of unknown DNA you want to sequence. But this leaves you with just a single, useful molecule; unless you're Helicos BioSciences or one of the more exotic techniques that are currently in development, that's not good enough; there's too much potential for noise to swamp the signal you need to read the sequence of a single DNA molecule. The rest of the newer sequencing technologies on the market all use a small population of identical molecules to ensure a stronger signal. The technique that creates this population of identical molecules is called Polymerase Chain Reaction, or PCR. Recall our description of DNA polymerase, which could start adding bases at the 3' end of a primer, and keep going until it either incorporated a terminating base, or ran off the end of a linear molecule. If you don't feed it any terminating bases, you can ensure that the latter will happen. The PCR reaction simply relies on getting DNA polymerase to copy to the end of a DNA molecule. We can start with the molecule we created above: an unknown sequence, flanked by two short sequences we know the identity of. If we warm up the solution containing this molecule, we can separate the two strands. Once we cool them down, primers that match our known sequences can bind (there is an excess of these primers around, so having them bind is more probable than having the two strands stick back together. By making sure that the primer has a specific sequence and 5'-3' orientation, we can ensure that it will only stick in one location. Once the primers are in place, the DNA polymerase can go to work, copying down each of the two strands. When the polymerase is done, we've double the DNA present: instead of a single copy of our molecule, we now have two. Heat it again with an excess of primers, and you can repeat the process, and two identical molecules will be replaced by four. Keep repeating it, and you'll get an exponential amplification of the single molecule of DNA you started with, the process ending only when the primers or nucleotides run out, or the DNA polymerase breaks down. That last bit is rather significant. If you used the same polymerase that you used for DNA sequencing, the two strands of DNA wouldn't be the only thing that came apart when the solution was heated up; the polymerase would fall apart, as well. The trick, one that got someone a Nobel Prize, was using a DNA polymerase that could withstand high temperatures. The source of that polymerase was Thermus aquaticus, an organism that normally lives in hot springs (other, somewhat better polymerases are now commonly used. Three of the machines currently on the market—454, Illumina, and ABI's SOLiD—use PCR to create small groups of identical molecules, and then perform sequencing on the entire population at once. But the three approaches taken by these are radically different, as we'll see when we get to our next installment: the pyrosequencing used by 454 machines.
- Within a scroll bar, the box that can be moved in the desired direction, to navigate within a file or window. For instance, by utilizing a mouse to slide the elevator downwards within a vertical scroll bar, a user advances further ahead in a displayed document. Also called elevator, or scroll box. - verb to glance through the pages of a book or magazine - noun the short thick finger, with only two bones, which is separated from the other four fingers on the hand Origin & History of “thumb” The thumb is etymologically the ‘swollen’ part – an allusion to its greater thickness than the other fingers. along with its relatives German daumen and Dutch duim, it goes back to a prehistoric west Germanic thūmon. this in turn can be traced to Indo-European tum- ‘swell’, which also produced English tumour and tumult. The b in thumb appeared in the early middle English period, when it was still a two-syllable word (thumbe), and at first was pronounced, but it has fallen silent over the centuries.
When should I immunize my child to protect against pneumococcal disease? Your child is recommended to receive the immunizations that will protect him or her against pneumococcal disease, at the following ages: Dose 1 - Pneumococcal conjugate Dose 2 - Pneumococcal conjugate Dose 3 - Pneumococcal conjugate Please Note: Children at high risk of invasive pneumococcal disease will be given an additional dose of this vaccine at six months of age. This additional dose, for high risk children only, would be followed by the routine 12 month dose. Pneumococcal Disease quick facts: Pneumococcal disease is a bacterial infection. It can cause meningitis (an infection of the covering of the brain and spinal cord), bacteremia (an infection of the blood), pneumonia and middle-ear infections. It can result in death or long-term impacts such as deafness and brain damage. Pneumococcal disease is easily spread through sneezing or coughing and from saliva (e.g. kissing, sharing food, sharing toys). What can happen to my child if he or she gets pneumococcal disease? Sadly, the disease is quite serious for infants and young children. In fact, for every 20 children who get sick with pneumococcal disease, up to five will die. Infections caused by pneumococcal disease can also cause lifelong damage to the brain, the ears and major organs. About the immunization: Pneumococcal disease can be prevented through immunization. The vaccine that protects your child against pneumococcal disease is called the pneumococcal conjugate (PNEU-C13) vaccine. When your child gets the pneumococcal conjugate (PNEU-C13) vaccine, your child’s immune system will be prompted to build antibodies that protect – or “arm” – your child against pneumococcal disease. Children with certain health problems (e.g., heart, lung, kidney, liver problems; diabetes; weak immune system) should also get a vaccine called pneumococcal polysaccharide (PNEUMO-P) when they are 2 years of age or older. Your child cannot get pneumococcal disease, or any other diseases, from the pneumococcal conjugate (PNEU-C13) or the pneumococcal polysaccharide (PNEUMO-P) vaccine. These vaccines are safe, and provide your child with protection against a disease that is not safe. The risk that pneumococcal disease poses to your child’s health is far greater than any risk related to immunizing your child against pneumococcal disease. Safety checks before immunization Your nurse will talk to you about your child’s health history before giving your child any vaccines. This will include questions about any medicines your child is taking, health conditions your child has or is experiencing, as well as any allergies your child may have. Your nurse will guide you on what is safe for your child, based on your child’s health history. When your nurse talks to you about your child’s health history, it is important that you inform your nurse if your child: - is sick or has a fever greater than 38.5 C (101.3 F) - has allergies to any part of the vaccine - is allergic to any foods, drugs, bee stings, etc. - has a weakened immune system (immune compromised) - has had an allergic reaction (such as anaphylaxis) to this or other vaccines in the past. Your nurse will guide you on what is safe for your child, based on your child’s health history. PLEASE NOTE: Your child should NOT get the vaccine if he/she has had a severe allergic reaction (anaphylaxis) to this vaccine in the past. What might my child experience after immunization? Reactions to PENU-C13 and PNEUMO-P vaccine are usually mild, go away within a few days, and may include: - redness, swelling and soreness in the area where the needle was given - feeling tired, irritable - headache or body aches - fever or chills - poor appetite, vomiting, or diarrhea Unexpected or unusual reactions can happen after being immunized. Call Health Link at 811 to report any unusual reactions. How can I manage my child’s symptoms after immunization? No matter your child’s age, it is normal for him or her to experience some common, mild and temporary symptoms after immunization. Here are a few tips to manage these mild symptoms: - Fever. If you need medicine for fever or pain, check with your pharmacist or doctor. Follow the instructions on the medicine package carefully. If you are not sure whether your child’s fever is related to the immunization, dial 811 for Health Link or talk to your doctor or pharmacist, before giving your child medicine. Do not give aspirin to anyone younger than 19 years of age. Aspirin increases the risk of a rare but serious disease called Reye Syndrome. - Swelling or redness around injection point. Put a cool moist cloth on the area for about 10 to 20 minutes. Talk to your pharmacist or doctor if you need medicine to help relieve the discomfort. Follow the instructions on the medicine package carefully. - Fretfulness and poor appetite. Sometimes a baby may be fretful, drowsy and refuse to eat for a few hours after immunization. Plan to relax in a quiet environment at home after immunization. Hold and cuddle your child when needed, and remember to keep the temperature at a comfortable level – your child is more likely to be fretful if he or she gets too warm. Severe allergic reactions after immunization are rare, occurring at an estimated annual rate of only one to ten per one million doses of vaccine administered, and can be treated. Our nurses will ask that you stay with your child, in the immunization clinic, for at least 15 minutes after your child receives his or her immunizations. For the dose that your child receives in school, the nurse will also require your child to stay for at least 15 minutes after his or her immunization. This will allow the nurse to identify and treat any immediate allergic reaction that could occur. If you are concerned about symptoms your child is experiencing after immunization, dial 811 for Health Link to speak to a registered nurse, 24 hours a day, seven days a week. If your child is experiencing severe shortness of breath, call 911.
Asperger’s Syndrome is what is known as a High functioning form of Autism The term High functioning can be confusing for 2 reasons 1. High functioning is not a reference to being intellectually gifted but to having a far less severe form of Autism than those diagnosed with Classical/Kanner Autism - However a diagnosis of Asperger’s Syndrome will usually mean the person has an above average IQ - People with Asperger’s Syndrome can also be intellectually gifted, some at Genius level, although as in the non-Autistic population this is the exception 2. Anyone who has Asperger’s Syndrome, including the intellectually gifted, experiences lifelong clinical impairment in a number of key areas such as: - Social intuition - Communication and emotional control - Unusual learning styles - Difficulty with organization - Physical clumsiness including in some cases Dyspraxia - Hypersensitivity to light, sounds, smells, textures and touch Being a Spectrum condition the severity of each individual impairment will vary from person to person. Those diagnosed with Asperger’s Syndrome will not have experienced any significant delay in speech development. In our label addicted World, the word Spectrum is a refreshing acknowledgement and reminder of the incredible diversity within the Autism community. The Autism Spectrum is itself overlaid by other ability Spectra including physical and intellectual, hence the saying. When you’ve met one Autistic person, you’ve met one Autistic person! Autism is a lifelong developmental condition that delays or impairs - Communication and social skills - Behavior skills - Learning skills There is no known cure for autism. But early intervention and treatment can help children develop these skills and can add considerably to the quality of their life and the lives of their families.
After listening to this lesson, you can form simple present tense sentences like “It’s water.” “It’s me.” or “It’s a dictionary.” and you can also ask “What is it?” in Korean. The basic way in which Korean sentences are formed is different from the way English sentences are formed because the position of the verb in a sentence is different. In Korean, the verb “to be” comes AFTER a noun, and you can learn how to form simple “to be” sentences in Korean by listening to this episode of TalkToMeInKorean. Be sure to use the free PDF attached to this lesson as well. You can download both the PDF lesson notes and the MP3 audio track for this lesson below, and if you want to learn with our various textbooks and workbooks, you can get them on our online bookstore at MyKoreanStore.com. If you have any questions about this lesson, please leave us comments below! Go to the Grammar Curriculum page to see all of our grammar lessons.
Join students Sophie, Tomás, Emma, and Marcus during Fifth Period! This STEM comic strip chronicles the exciting and often hilarious adventures of a close-knit group of four friends as they learn about science, technology, engineering, and math from their kooky, inspiring, off-the-wall science teacher, Mr. Kepler. When they're not in class, these kids love to explore the vast world of STEM on their own, launching weather balloons, programming computer games, and cataloging insects, sometimes with unpredictable and highly entertaining results! Check back on the first and third Friday of every month for a new Fifth Period strip! Marcus Puts the Spin on Force How is Marcus able to turn a bucket of water over his head without getting soaked? The same way someone can throw a ball over his head without it dropping on him. Objects that are moving want to keep moving in a straight line. Because gravity acts on objects all the time, though, they will follow an arc as they travel through the air on their own. If they move very fast, the arc looks almost straight, and if they move slowly, it looks more...archy. In this case, Marcus uses the bucket to pull the water toward himself to make the water go around in a circle instead. The faster it goes, the harder he needs to pull toward the center (called a centripetal force) to keep it moving in a circle. Unfortunately for Mr. Kepler, the bucket handle breaks when it’s Emma’s turn, and both the water and the bucket “go ballistic” (remember that?) following the arced path instead...that leads to his head. Try it yourself! Next time you’re at a playground, take a spin on the merry-go-round. Notice how you need to pull yourself toward the center to keep your body going around in a circle, and you have to pull harder the faster you spin? You’re using centripetal force!
The Jabiru (Jabiru mycteria) is a large stork found in the Americas from Mexico to Argentina, except west of the Andes. It is most common in the Pantanal region of Brazil and the Eastern Chaco region of Paraguay. It is the only member of the genus Jabiru. The name comes from the Tupi-Guaraní language and means "swollen neck". The name Jabiru has also been used for two other birds of a distinct genus: the Asian Black-necked Stork (Ephippiorhynchus asiaticus), commonly called "Jabiru" in Australia; and sometimes also for the Saddle-billed Stork (Ephippiorhynchus senegalensis) of sub-Saharan Africa. In particular, Gardiner's Egyptian hieroglyph G29, believed to depict an E. senegalensis, is sometimes labeled "Jabiru" in hieroglyph lists. In Portuguese, the bird is called jabiru, jaburu, tuiuiu, tuim-de-papo-vermelho ("red-necked tuim", in Mato Grosso) and cauauá (in the Amazon Basin). The name tuiuiu is also used in southern Brazil for the Wood Stork (Mycteria americana). The proposed Late Pleistocene fossil stork genus Prociconia from Brazil might actually belong into Jabiru. A fossil species of jabiru was found in the early Pliocene Codore Formation near Urumaco, Venezuela; it has not yet been described (Walsh & Sánchez 2005). The Jabiru is the tallest flying bird found in South America and Central America, often standing around the same height as the flightless and much heavier American Rhea. The adult Jabiru is typically 122-140 cm (48-55 in), 230-280 cm (90-111 in) across the wings, and weigh to 8 kg (17.6 lbs). The larger males may stand as tall as 1.5 m (5 feet). The beak, up to 30 cm (1 ft) long, is black and broad, slightly upturned, ending in a sharp point. The plumage is mostly white, but the head and upper neck are featherless and black, with a featherless red stretchable pouch at the base. The sexes are similar, although the female is usually smaller than the male. While it is an ungainly bird on the ground, the Jabiru is a powerful and graceful flier. The nest of twigs is built by both parents around August–September (in the southern hemisphere) on tall trees, and enlarged at each succeeding season growing to several meters in diameter. Half a dozen nests may be built in close proximity, sometimes among nests of herons and other birds. The parents take turns incubating the clutch of 2 to 5 white eggs.
Computer Architecture Questions 1. Explain what is DMA? 2. What is pipelining? 3. What are super scalar machines and vliw machines? 4. What is cache? 5. What is cache coherency and how is it eliminated? 6. What is write back and write through caches? 7. What are different pipelining hazards and how are they eliminated. 8. What are different stages of a pipe? 9. Explain more about branch prediction in controlling the control hazards 10. Give examples of data hazards with pseudo codes. 11. How do you calculate the number of sets given its way and size in a cache? 12. How is a block found in a cache? 13. Scoreboard analysis. 14. What is miss penalty and give your own ideas to eliminate it. 15. How do you improve the cache performance. 16. Different addressing modes. 17. Computer arithmetic with two’s complements. 18. About hardware and software interrupts. 19. What is bus contention and how do you eliminate it. 20. What is aliasing? 21) What is the difference between a latch and a flip flop? 22) What is the race around condition? How can it be overcome? 23) What is the purpose of cache? How is it used? 24) What are the types of memory management?
A remarkable finding of this five-year study is that Neanderthals grow their teeth significantly faster than members of our own species, including some of the earliest groups of modern humans to leave Africa between 90-100,000 years ago. The Neanderthal pattern appears to be intermediate between early members of our genus (e.g., Homo erectus) and living people, suggesting that the characteristically slow development and long childhood is a recent condition unique to our own species. This extended period of maturation may facilitate additional learning and complex cognition, possibly giving early Homo sapiens a competitive advantage over their contemporaneous Neanderthal cousins.Or it may just be an evolutionary adaptation to a warmer climate and less of a need to maintain selection for a quicker development. This is especially true in light of the fact that there is no evidence that modern humans were any more intelligent than their Neandertal precursors. As I have said before, if you lived in a world in which the tundra line was at Vienna, you'd have a hard time adapting, too. Thursday, November 18, 2010 Modern Humans Have Slower Developmental Timing than Neandertals ScienceDaily has a story in which a synchrotron x-ray machine has revealed that Neandertals had faster developmental timing patterns than modern humans and that this may have given modern human an advantage. They write:
Respiratory syncytial virus Respiratory syncytial virus (RSV) infects people of all ages causing similar symptoms to influenza and occurring at about the same frequency. The virus is highly contagious - virtually all infants under the age of two will be infected with RSV, and reinfection is common. For example, roughly 50% of children will experience two RSV infections by the age of two. RSV is the most common cause of bronchiolitis and pneumonia in children under one year of age, and according to the World Health Organisation (WHO) is the single most important cause of severe lower respiratory infections in infants and young children. The Centers for Disease Control and Prevention (CDC) state that 25 to 40% of young children will have signs of bronchiolitis and pneumonia during their first RSV infection, and 0.5-2% will require hospitalisation. In particular, RSV can cause severe or life-threatening illness in infants who are born prematurely or who have chronic lung or heart disease. The WHO estimates global annual infection and mortality figures for RSV to be 64 million and 160,000 respectively. In the U.S., estimates put RSV associated hospitalisations at between 125,000 and 250,000 per annum. RSV can also have serious consequences in the elderly and highly immunocompromised patients such as bone marrow transplant patients. It is estimated that 14,000 elderly and high-risk adults die annually from an RSV infection in the US. RSV is believed to be responsible for more than 177,500 hospitalisations of adults each year at a cost to the U.S. healthcare system that exceeds $1 billion. RSV enters cells in the lung by using a protein, called a fusion glycoprotein, found on the virus's outer envelope. Biota has discovered small-molecule, orally bioavailable, antivirals known as fusion inhibitors (FI) that specifically target this essential fusion glycoprotein, preventing it from functioning and therefore stopping RSV infection from spreading.
What is a lumbar puncture? A lumbar puncture is also called a spinal tap or LP. It is a test when a doctor inserts a needle in the lower back to get a sample of cerebrospinal fluid (CSF) that moves around the brain and spine. The needle does not go near the spinal cord. Why would my child need a lumbar puncture? The lumbar puncture is usually done to find out if your child has an infection of the lining or the fluid around their brain. This type of infection is called meningitis (see Meningitis fact sheet). Occasionally lumbar punctures are done for other reasons that your doctor will explain. How is it done? - The doctor or nurse may put a local anaesthetic patch on the skin first to numb the area where they will put the needle. It takes about half an hour for the patch to work. - If your child is very scared or anxious the doctor may give them some medicine that will help them to relax. - Using distraction strategies and play activities may be helpful for your child. Child life therapy services may be available at your hospital and you could discuss this with your doctor or nurse. - It is very important that during this test your child does not move so a nurse will hold them gently but firmly to make sure they stay still. - Your child must lie curled up on their side with their knees tucked up under their chin. - A doctor will clean the skin on the lower half of your child’s back and then carefully insert the needle, as seen in the picture below. - The drops of spinal fluid are collected quickly into small tubes, and then the needle is removed. The test may be a little bit awkward as your child needs to be still the whole time and may feel some discomfort. This image was provided courtesy of KidsHealth. © 1995- 2009. The Nemours Foundation. All rights reserved. What problems can occur? - The doctor will make sure that it is safe for your child to have the test and there are very few side effects from a lumbar puncture. - After the test a small number of children may complain of feeling sore where the needle went in, and some may have a headache for up to a couple of days. - Complications such as nerve trauma and infection are very rare. A lumbar puncture is done below where the spinal cord ends, so it is not possible to injure the spinal cord. On occasions a headache may occur post lumbar puncture. This may be noticed on mobilizing. Good hydration, lying down for a period if the headache occurs and slow mobilization will help. What happens after the lumbar puncture? If the lumbar puncture is done to look for infection, the results will usually be available within a few hours. There may be a dressing or bandaid covering the spot where the needle went in. You may notice a little bit of swelling where the needle went in, but this should disappear over the next couple of days. What can I do to help during the test? - If your child asks about what is happening, be honest. Reassure them and explain the test in simple terms. - You may be able to comfort and reassure your child while the lumbar puncture is being done. However, if you are not able to stay with your child, then a staff member will stay and comfort them. - The staff are there to help and you are welcome to ask them if you would like more information. What can I do to help after the test? - If your child complains of a headache or a sore back, it may be helpful to give your child some mild pain relief such as Panadol (Paracetamol) and allow your child to rest. - If the headache becomes severe or does not go away your child should see their doctor.
Frogs are amphibians. This means that a frog’s skin should remain moist all the time. If a frog’s skin is not moist, they are unable to breathe. This is why you usually find frogs near sources of water and in humid climates. From the very beginning, a frog’s life revolves around water. They hatch from eggs that are developed beneath the surface or in damp areas cased in moisture. What Do Frog Eggs Look Like? Frogs spawn refers to the eggs in gel-like sacks that provide moisture. These take the form of either a large blob or a spread-out flat grouping mat. Within the frogspawn, the eggs are circular and see-through. Appearance Of Frog Eggs So what do frogs eggs look like? The appearance of frog eggs can seem a little ‘other-worldly’. Some people relate the appearance of frog eggs to clusters of grapes. Frog eggs do vary from species to species, but the overall appearance of the egg itself is the same. The embryo of the egg is black and can be seen through the egg mass. The egg mass can either be clear, a slightly milky color, or have a hint of green to it. The egg mass provides an extra layer of protection for the eggs. As the eggs continue their development, you can see the tadpole as it forms inside. The eggs are completely encased in a gel-like sack, grid, or strand. The gel serves many purposes; it keeps the frogspawn together and protects the eggs from drying out. The eggs can be found in different locations from species to species. When looking for frogspawn, you may come across it in many different fashions. This could include gel-like sacs below shallow water, floating on the surface, or kept in place by plants. How Frogs Release Eggs The frogs’ breeding season begins after hibernation. The female frog has been developing eggs constantly. When they find a mate, the male frog will get onto the female frog’s back and tightly wrap his arms around her. This in turn causes pressure and the female frog releases the eggs that have matured. The male frog then fertilizes them immediately. The eggs are enveloped by a gel-like substance. Together, this is referred to as frogspawn. If the eggs are released into water, the frogspawn will sink to the bottom until it absorbs enough moisture to float. How Frog Eggs Are Protected Frog eggs need constant moisture if there is any hope of survival. Frogs that have their eggs in the water further ensure that the eggs will not dry out by creating the gel-like frogspawn. This absorbs water and keeps the eggs contained. However, not all frogs release their eggs into the water. Some frog species have their eggs on land. Since the eggs do not possess a shell, they’re defenseless against the elements. There are species of frogs that ‘carry’ their eggs with them. Eggs can be visible on the backs of some frog species. While others take a very different approach and the male carries the eggs in his throat until the time when they begin to hatch. In places like the rainforest where there are many species of treefrogs, their eggs can be found in damp clusters of leaves above the water. Once the tadpoles emerge from the eggs, they fall from the trees directly into the water beneath where they continue their growth. When it comes to protecting frog eggs from potential predators, adult frogs do not watch over them. However, that’s where the placement of the frog spawn comes into play. Frogs look for sheltered areas that are secluded. Both frogs that release their eggs in water and on land, look for dense plant life that can protect the eggs from view. In areas of high prey, the method of having their eggs in a grid-like frogspawn gives them a higher chance that a predator might snatch a few, but the rest will survive. Frequently Asked Questions About What Frog Eggs Look Like How do you tell the difference between frog eggs and other types of amphibians? Frog eggs are unique in the shape of the outer protective layer that holds their eggs in a cluster. Many other amphibians, such as toads, have eggs that they release in long strands. How many eggs do frogs have? While the frog species play a significant role in this country, they can release anywhere between 2,000 to 20,000 eggs at a time. If I have frog eggs in my pond, can I safely move them? While it is possible to move frogspawn, it is not recommended as you can damage it. If it is necessary, put it into a large bucket of water and let it remain there until the frogspawn hatches into tadpoles. They can then be relocated. The appearance of the frog egg is unique. Both the method in which they incase their eggs in the gel-like sack and the fact that the eggs themselves are clear, are not something you see frequently. While they may look other-worldly, the protective gel and egg mass execute the job of keeping the frogspawn safe until they are ready to hatch.
Definition: Traumatic Brain Injury (TBI) is caused by a blow or jolt to the head which disrupts normal brain function or by a foreign object penetrating the skull. Studies have found that the four most common causes of TBIs are falls, motor vehicle and traffic accidents, struck by/against events, and assaults (Centers for Disease Control and Prevention’s Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations and Deaths 2002-2006 webpage). The CDC estimates that in the U.S. around 1.7 million people sustain a TBI every year. TBI is a contributing factor in almost one third of all injury deaths. In addition: Strategies for preventing TBIs include:
Culturally Responsive Practices Students of color are at an increased risk of psychological distress, suicide, problem behavior, and decreased academic success as compared to their peers (Aud et al., 2011; Blake et al., 2011; Cholewa et al., 2014). Culturally responsive pedagogy (CRP) in education has developed as a way to improve the belonging, engagement, and academic achievement of students with diverse cultural backgrounds (Cholewa et al., 2014; Sampson & Garrison-Wade, 2011). According to Cholewa et al. (2014), CRP in the classroom involves using language that is respectful of diverse cultures, building on existing knowledge and familiar communication styles, and integrating music and dance. Educators’ use of CRP can help students feel more excitement towards the curriculum. One teacher, Mrs. Morris, drew from her students’ unique backgrounds to enhance her curriculum and pedagogy in a predominantly African-American school (Cholewa et al., 2014). She incorporated African-American values, such as communalism, and music and dance styles popular among African-American students. She also used a call and response communication style to engage her students in answering questions. The energy and vitality she created through CRP promoted zest and engagement in her classroom (Cholewa et al., 2014). Similarly, one social studies teacher incorporated his students’ cultural backgrounds into his history lessons (Sampson & Garrison-Wade, 2011). Students particularly enjoyed his lessons on the history of the origin and evolution of the usage of the “N word", his rap version of the Declaration of Independence, and field trips to the African American Research Library and a Tortilla Factory. Many students reported that these activities were engaging, fun, and helped them feel valued and understood (Sampson & Garrison-Wade, 2011). As you evaluate your use of CRP, it is important to know your students and adapt your lessons accordingly. The Greater Good Science Center at UC Berkeley recommends considering the what, who, why and how of your teaching and asking yourself questions such as: - “Are there stereotypes or prejudices that this lesson or practice may implicitly promote?” - “How is this lesson or practice relevant to all of my students?” - “How might my beliefs about this topic, lesson, and/or practice differ from my students’ and their families’ beliefs? Does this practice privilege my values over theirs in any way?” Cholewa, B., Goodman, R.D., West-Olatunji, C., & Amatea, E. (2014). A qualitative examination of the impact of culturally responsive educational practices on the psychological well-being of students of color. Urban Review, 46, 574–596 https://edtechbooks.org/-wBfT Sampson, D., & Garrison-Wade, D. (2011). Cultural vibrancy: Exploring the preferences of African American children toward culturally relevant and non-culturally relevant lessons. Urban Review, 43, 279–309. https://edtechbooks.org/-EHTU Greater Good Science Center. (n.d.). Making practices culturally responsive. https://edtechbooks.org/-rRst End-of-Chapter Survey: How would you rate the overall quality of this chapter? - Very Low Quality - Low Quality - Moderate Quality - High Quality - Very High Quality
Environment and Racing: Middle & High School Examine geology and weather’s impact on racing. Weather and Racing - Examine geology and weather’s impact on racing - Utilize weather data to predict race implications 1. Worksheet PDF 2. Photos and images 3. NASCAR background informational sheet 4. Bike or inflatable device (toy) 5. Tire gauge 6. Air pump 7. Hose with sprinkler feature 8. Surfaces like asphalt, grass, concrete and dirt/clay 9. Temperature gauge (such as the app Smart Temperature - lay your smart device down to monitor temperature reading) Lesson Plan and Procedures 1. Read the NASCAR background informational sheet and view suggested photos and web links. 2. Complete the worksheet using these resources. 3. Conduct an experiment(s) using weather conditions, surfaces and air pressure. a. Locate three different types of surfaces in your neighborhood such as asphalt, concrete, grass or dirt/clay. b. Measure the temperature of each surface for at least 10 minutes at 1-hour intervals between 8 a.m. and 6 p.m. c. Record the time and your readings on the worksheet for each type of surface. d. Plot your data by time and temperature. e. What did you observe? What impact might this have on rubber tires? Kick It Up a Notch Experiment: Using a bike, try riding on the different surfaces at different times of the day. Make notes of how the surfaces may change or feel different to ride on. Did any become easier (requiring less energy/less pedaling) or harder? Make It Rain Experiment: Using a hose with a sprinkler attachment, wet your surfaces and record the changes in temperatures. Did the temperatures go up or down? Riding After the Rain Experiment: Using your bike, try riding on each of the surfaces after it has rained – if possible, within 15 minutes after its stops. What changes did you notice by the surfaces being wet and interacting with your tires? Air Pressure Experiment: a. Please get your parent’s permission before beginning this experiment! If you have a bike, air pump and tire gauge (to measure air pressure), you can conduct this experiment. If you have an inflatable tire or other inflatable rolling device, you can substitute it for the bike, but you’ll need a family member or friend to assist you. b. Measure the full/recommended inflation of your tire. Recommended tire pressure is printed on the sidewall of the tire, or you can look up the psi (pressure) online. c. Ride on the surfaces you have been tracking. Note any observations you have about performance and handling, or steering and control. d. Reduce the tire pressure by 3 psi. Then, retest the surfaces by riding on them. Note your observations on the worksheet. Do not deflate tires beyond 30 percent of the recommended pressure; you may cause permanent damage to the tube inside the bike. e. Re-inflation the tire to its recommended pressure, and then add 1 to 3 psi. Go for a ride and note your observations for handling on the worksheet. Do not overinflate tires beyond 10 percent above the recommended pressure, or tire tubes may blow/break. f. Chart your readings and performance. 4. Wrap Up: You’ve had a chance to experiment with some of the environmental factors that impact racing which crew chiefs, engineers and drivers experience. Drivers need to provide live and real-time feedback on the car’s performance, which in many cases is tied to the environmental influences on the car. Crew chiefs and engineers need to prepare before, during and after the race to understand how the environmental factors impacted the car and what they need to do in future races. All the data collected is retained year after year and referenced at races at the same track.
In Object-oriented programming, at the class level, we use class methods and static methods. - Class methods: Used to access or modify the state of the class. if we use only class variables, we should declare such methods as a class method. - Static methods: A static method is a general utility method that performs a task in isolation. Inside this method, we don’t use instance or class variable because this static method doesn’t take any parameters like After reading this article, you’ll learn: - How to create and use the static methods in Python - Create staticmethod using the Table of contents What is Static Methods in Python A static method is a general utility method that performs a task in isolation. Static methods in Python are similar to those found in Java or C++. A static method is bound to the class and not the object of the class. Therefore, we can call it using the class name. A static method doesn’t have access to the class and instance variables because it does not receive an implicit first argument like cls. Therefore it cannot modify the state of the object or class. The class method can be called using ClassName.method_name() as well as by using an object of the class. class Employee: @staticmethod def sample(x): print('Inside static method', x) # call static method Employee.sample(10) # can be called using object emp = Employee() emp.sample(10) Define Static Method in Python Any method we create in a class will automatically be created as an instance method. We must explicitly tell Python that it is a static method using the @staticmethod decorator or Static methods are defined inside a class, and it is pretty similar to defining a regular function. To declare a static method, use this idiom: class C: @staticmethod def f(arg1, arg2, ...): ... Example: Create Static Method Using To make a method a static method, add @staticmethod decorator before the method definition. @staticmethod decorator is a built-in function decorator in Python to declare a method as a static method. It is an expression that gets evaluated after our function is defined. In this example, we will create a static method gather_requirement() that accepts the project name and returns all requirements to complete under this project. Static methods are a special case of methods. Sometimes, you’ll write code that belongs to a class, but that doesn’t use the object itself at all. It is a utility method and doesn’t need an object ( self parameter) to complete its operation. So we declare it as a static method. Also, we can call it from another method of a class. class Employee(object): def __init__(self, name, salary, project_name): self.name = name self.salary = salary self.project_name = project_name @staticmethod def gather_requirement(project_name): if project_name == 'ABC Project': requirement = ['task_1', 'task_2', 'task_3'] else: requirement = ['task_1'] return requirement # instance method def work(self): # call static method from instance method requirement = self.gather_requirement(self.project_name) for task in requirement: print('Completed', task) emp = Employee('Kelly', 12000, 'ABC Project') emp.work() Completed task_1 Completed task_2 Completed task_3 Advantages of a Static Method Here, the static method has the following advantages - Consume Less memory: Instance methods are object too, and creating them has a cost. Having a static method avoids that. Let’s assume you have ten employee objects and if you create gather_requirement()as a instance method then Python have to create a ten copies of this method (seperate for each object) which will consume more memeory. On the other hand static method has only one copy per class. kelly = Employee('Kelly', 12000, 'ABC Project') jessa = Employee('Jessa', 7000, 'XYZ Project') # false # because seperate copy of instance method is created for each object print(kelly.work is jessa.work) # True # because only one copy is created # kelly and jess objects share the same methods print(kelly.gather_requirement is jessa.gather_requirement) # True print(kelly.gather_requirement is Employee.gather_requirement) - To Write Utility functions: Static methods have limited use because they don’t have access to the attributes of an object (instance variables) and class attributes (class variables). However, they can be helpful in utility such as conversion form one type to another. The parameters provided are enough to operate. - Readabiltity: Seeing the @staticmethodat the top of the method, we know that the method does not depend on the object’s state or the class state. Some code might use the old method of defining a static method, using staticmethod() as a function rather than a decorator. You should only use staticmethod() function to define static method if you have to support older versions of Python (2.2 and 2.3). Otherwise, it is recommended to use the function: It is the name of the method you want to convert as a static method. - It returns the converted static method. class Employee: def sample(x): print('Inside static method', x) # convert to static method Employee.sample = staticmethod(Employee.sample) # call static method Employee.sample(10) staticmethod() approach is helpful when you need a reference to a function from a class body and you want to avoid the automatic transformation to the instance method. Call Static Method from Another Method Let’s see how to call a static method from another static method of the same class. Here we will class a static method from a class method. class Test : @staticmethod def static_method_1(): print('static method 1') @staticmethod def static_method_2() : Test.static_method_1() @classmethod def class_method_1(cls) : cls.static_method_2() # call class method Test.class_method_1() static method 1 Referance: Static method documentation
Animals > Mammals > Giraffe The giraffe is a mammal with a very long neck, long legs, and hooves. Giraffes have short horns covered with fur. They live in Africa and eat the tops of tress. They are the tallest animal that lives on land. Review the giraffe theme lesson plan and crafts to present additional information, images and other activities about Alphabet Activities > Letter G is for Giraffe Present and display your option of letter G printable activities in the materials column. Children Age 3 and under: * Print letter G coloring page D'Nealian or Standard Block font and a giraffe coloring image #1 behind it or on a separate page if using paints to decorate later.Discuss other letter G words found on the worksheet. * Finger Tracing: Trace letter G's in upper and lower case with your finger as you also sound out the letter. Invite the children to do the same on their coloring * Children can trace and color the letter G's. After completing coloring the letter, encourage children to color the giraffe image. Write the word giraffe on the finished coloring page. Ages 3+ to 6 Alphabet - beginning letter G ( soft G sound) Trace, color and give spots to the giraffe activity: - Printing > two methods: print to white paper, trace letters and word, and color the giraffe yellow, or print to yellow paper, trace and give spots to the giraffe. - How to give spots to the giraffe: Use fingerprints, bingo marker, Q-tips or the eraser of an unsharpened pencil dipped into black paint or washable ink pad. Present the Letter G Worksheet and Mini Book program. Read suggested instructions for using the worksheet and mini-book. These materials can be used as part of Letter G program of activities to reinforce letter practice and to identify related G words. Display letter G posters and coloring pages or make a letter G classroom book with letter G Finger and Pencil Tracing:Trace letter G's in upper and lower case with your finger as you also sound out the letter. Invite the children to do the same on your worksheet. Encourage the children to trace the dotted letter, and explain the direction of the arrows and numbers that help them trace the letter correctly. During the demonstration, you may want to count out loud as you trace so children become aware of how the number order aids them in the writing process. Find the letter G's: Have the children find all the letter G's in upper and lower case on the page and encourage them to circle Advanced independent handwriting practice: 1. Print your choice of printable lined-paper and encourage children to draw a giraffe behind the page or print agiraffe coloring page image #1 paper Encourage children to draw and color a giraffe and write letter G g. Letter G coloring Letter G Worksheet & Mini-Book (soft G sound) D'Nealian & Standard block Drawing & writing paper Giraffe coloring pages
Posted: March 17th, 2022 Using what you have learned about your topic from your literature search, you are working towards formulating a research purpose and question. Note that in the Learning Resources for this week, the language of qualitative research is incorporated into how the research purpose and question is formulated. Here are some basic do’s and don’ts. Examine differences, effects, or impact Broad, open-ended questions For example, in the ongoing scenario for each of the weeks of this course, the qualitative research question is formulated based on: DO: The purpose of this study is to understand the narratives of childcare and support in families in impoverished communities. DO: What is the meaning of a “well-behaved child” to early childhood caregivers in impoverished neighborhoods? While as in this example, the research question is formulated based on quantitative information DON’T: The purpose of this study is to examine the demographic and family factors that predict the use of childcare services in impoverished communities. DON’T: What are the differences in early childhood social skill acquisition between children that do receive childcare services and those that do not? For this Discussion, you will examine qualitative research as it relates to qualitative design considerations. To prepare for this Discussion: Review the Learning Resources and the Fundamentals of Qualitative Research Methods: Developing a Qualitative Research Question video and consider the basic guidelines for qualitative research design. Use the Course Guide and Assignment Help found in this week’s Learning Resources and search for a qualitative research article. (Note: This article should be the research article you are using for your Major Assignment 1.) Review the qualitative research article you found and identify each of the components of the research design and consider what is present and what is missing. Identify what the authors did to document positionality, reflexivity, and bias. Transform your notes from your preparation work into three paragraphs and post the following: A brief statement of the purpose and primary research question the article addresses An assessment of how thoroughly the research design was presented, including what was missing An assessment of the extent of the researcher’s presentation of positionality, reflexivity, and bias Yale University. (2015, June 23). Fundamentals of qualitative research methods: Developing a qualitative research question (Module 2) [Video file]. Retrieved from https://www.youtube.com/watch?v=_0HxMpJsm0I Note: The approximate length of this media piece is 12 minutes. Place an order in 3 easy steps. Takes less than 5 mins.
Alternative energy, the gateway to the future and the wiping away of the reliance on limited resources of fuel. Oil, is a limited resource and it is something world needs constantly. Transportation, heat, and power, are all fueled by this substance. With everyone drawing from a well eventually it will run dry. While some look to the sun, Hydrogen or to electricity to power vehicles, a quicker solution would be to look to nature itself. Biomass and Biofuels exist all around us and they have within them an unlocked potential. Biomass, comes from living or recently alive organisms. Biomass or biological material more often refers to plant or plant-derived materials. This renewable form of energy can be harnessed through two separate means. The first process is through combustion. The second process is build on top of the first. After the biomass goes through the combustion process, the biomass can be further refined into different forms of "biofuel" There are three forms of combustion that can be used to convert biomass into a useable form of energy. Thermal or heat conversion is the process of using heat as a primary mechanism to convert biomass to biofuel. Chemical conversion has a range of different sub processes within it, but gasification is the most common form. Biochemical conversion makes use of nature's natural way of breaking down materials through the use of enzymes and other microorganisms. From here the fuel can be separated into two different categories, first and second generation. First generation biofuels came from sugarcane, corn starch and other things from nature. The sugars within these fuels are used in the production of bioethanol. Bioethanol can be used in fuel cells and be serve as an alternative to gasoline. Second generation biofuels, consists Lignocellulose biomass or dry plant matter such as wood. While this is the more widely used biofuel technological issues prevent this source of biofuel from being used more often. Such issues as chemical inertness and structural rigidity must be further mastered. What makes second generation biomass a better form of and bamboo can all be grown relatively quickly to support the fuel and energy industry. All living things which make up biomass and biofuel go through what is known as carbon fixation which is part of the carbon cycle. Carbon dioxide along with other molecules such as nitrous oxide and water vapor make up what are known as greenhouse gases. In regards to carbon dioxide levels within the ozone layer it is said that a proper balance is required in order to stop further progression of global warming. There are two sides of the argument to whether or not biofuels can bring balance or further harm to the ozone layer. Research indicates that biomass fuel releases higher levels of carbon dioxide and nitrogen oxides then standard sources of coal and natural gas. The second theory states that biomass fuel will reduce further increase of carbon dioxide in Earth's atmosphere. Biomass is sometimes thought of as a carbon neutral source of energy. In other words the carbon dioxide from biomass is taken by other biological organisms through the carbon cycle. In order to harness biomass fuel into ethanol, manufacturing and processing of biomass is obviously needed. Normally there are ten steps involved when it comes to the conversion of biomass product into ethanol or useable fuel. The obvious first step is one would need a storage facility to house all the biomass. The second step is known as the extraction process. The cane is crushed by a series of roller mills. The small fibers and extracts are then taken to be boiled to clean and purify the fibers and extracts into a thickened syrup like mixture. The starch is then put through hydrolysis process. Step five is the fermenting of the product with yeasts enzymes. Step six, carbon recapture process to lower the carbon footprint of the bioethanol. The final steps involve further cleaning processes followed by further storage for the fuel you have now created. From an economic stand point, the economic stand point is this process is actually more expensive then the making of traditional forms of fuel. Analysts also state that if we were to make the switch it would be improper and in a matter of years, this alternative fuel source would cost more than natural gas. The steps taken to make biodiesel fuel are actually lower in count then that of the process to make bioethanol. Step one is the feedstock pretreatment. Recycled oil is processed to remove excess such as dirt, charred food and water. Within this process degumming to remove phospholids and other plant matter also occurs. Step two is the treatment of free fatty acids. Samples of cleaned feedstock oil is titrated with base solution to see if the sample contains vegetable oil samples. The acids are then either converted into biodiesels. After this the biodiesel is then sent through a purification process to separate the biodiesel from the byproduct. With further testing and federal backing perhaps we can be free of our dependence on natural gas and foreign oil in the years to come. While current research states biomass fuel's have its ups and downs, I believe we all can benefit from clean energy.
NASA is preparing a July 1 launch for its first satellite dedicated to measuring atmospheric levels of carbon dioxide, a greenhouse gas that plays a key role in climate change. CO2 levels have reached their highest point in at least 800,000 years, according to the US space agency. The Orbiting Carbon Observatory-2 (OCO-2) satellite is very similar to its predecessor, OCO-1, which was destroyed during its launch in February 2009. The satellite will help provide a more complete and global picture of man-made and naturally occurring CO2 emissions as well as the effects of carbon "sinks," like oceans and forests, which absorb and trap the gas. "Carbon dioxide in the atmosphere plays a critical role in our planet's energy balance and is a key factor in understanding how our climate is changing," said Michael Freilich, director of NASA's Earth Science Division. "With the OCO-2 mission, NASA will be contributing an important new source of global observations to the scientific challenge of better understanding our Earth and its future," he added in a statement. The OCO-2 satellite will be launched on a United Launch Alliance Delta II rocket from Vandenberg Air Force Base in California, aiming for an orbit at 438 miles (705 kilometers) above the Earth's surface. NASA envisions it becoming the lead satellite for a six-strong fleet that will circle the Earth every 99 minutes, allowing nearly simultaneous observations across the globe. OCO-2, designed to operate for at least two years, will take measurements of carbon emissions and carbon sinks around the world to help scientists analyze how they change over time. In April, monthly concentrations of carbon dioxide in the atmosphere surpassed 400 particles per million in the northern hemisphere, which NASA said was the highest level in at least the past 800,000 years. Human activities—including the burning of fossil fuels like oil, natural gas and coal—are blamed for emitting nearly 40 billion tonnes of CO2 in the atmosphere each year, leading to an unprecedented accumulation of the greenhouse gas. Climate scientists have concluded that the increase of CO2 emissions from human activities, especially from fossil fuels and deforestation, have upset the planet's natural carbon cycle, prompting rising temperatures and planet-wide climate change. Currently, less than half of the CO2 emitted by human activities remains in the atmosphere, scientists say. Measurements of CO2 levels taken by the new satellite will be combined with data obtained by land-based observatories, airplanes and other satellites.
Pakistan’s glacial melting woes Published: 2 May 2022 There are more than 6,000 glaciers in northern Pakistan, including Gilgit-Baltistan (GB) and Khyber Pakhtunkhwa (KP). These are clean water reservoirs that actually irrigate Pakistan. But these glaciers are changing rapidly due to climate change. The ecosystem of these areas is changing. Global warming has accelerated their melting and more lakes have been formed as a result. Flooding due to the melting endangers lives and livelihoods of millions of local people and adversely affects the ecology.
This is the course 2 of a three course specialization called Fundamentals of Immunology. Each course in the specialization presents material that builds on the previous course's material. This is the second half of the journey through the defenses your body uses to keep you healthy. In the first part we learned about innate immunity and B cell function. The second part covers T cell function and coordination of the immune response. Fundamentals of Immunology: T cells and Signaling builds on the first course to describe the functions of Complement, MHC presentation to T cells, T cell development and signaling. The early lectures survey cells, tissues and organs using metaphors, cartoons and models to improve understanding and retention. This course includes the structure of both MHC proteins and T cell receptors and the sources of variation. The course provides animations of gene rearrangement, developmental processes and signal cascades. Testing employs multiple choice questions testing facts, concepts, and application of principles. Questions may refer to diagrams, drawing and photographs used in lecture and reproduced in the outline. What You’ll Learn: How complement uses adaptive and innate triggers to target pathogens. The detailed structure and coding of MHC proteins and both alpha-beta and gamma delta receptors and how these proteins interact to initiate an adaptive immune response. The basics of signaling, and the varieties of external receipt and internal activation pathways. We bine the process of putting together how signals and crosstalk control the activity of the immune system.
Main Article Content To some extent, the survival of an organism depends on its ability to detect and adapt to changes in its environment on-the-fly. Living organisms have mechanisms for adapting to changes in their environment. To give one example of the well-known "fight or flight" reaction, a rush of adrenaline occurs when mammals perceive an abrupt change in their surroundings as hazardous.Physiological stress reactions in complex organisms necessitate the proper regulation of interactions between multiple organ systems. It is hoped that pinpointing specific processes that contribute to microbial survival under rapidly changing environments may provide light on the stress response systems of other organisms.pH, temperature, and nutrient scarcity are just a few of the environmental signals that cause bacteria to adapt to stressful conditions. They also direct the expression of virulence genes when and where it's most appropriate. Stress reactions and their management are consequently critical for an understanding of how germs cause disease.
Monarch butterflies (Danaus plexippus) are perhaps the most well-known and beloved butterflies in North America. A ubiquitous sight in gardens, prairies, and natural areas from coast to coast, their arrival in northern states and Canadian provinces is viewed by many as a welcome sign of the change in seasons from spring to summer. Renowned for their long-distance seasonal migration and spectacular winter gatherings in Mexico and California, the monarch butterfly population has recently declined to dangerously low levels. In the 1990s, hundreds of millions of monarchs made the epic flight each fall from the northern plains of the U.S. and Canada to sites in the oyamel fir forests in central Mexico, and more than a million monarchs overwintered in forested groves on the California coast. Now, researchers and community scientists estimate that only a fraction of the population remains—a decline of approximately 70% has been seen in central Mexico and a decline of >95% has been seen in California. The Xerces Society, government agencies, partner organizations, and communities are working across the U.S. to protect and restore habitat for monarch butterflies across a broad array of landscapes, provide workshops and educational resources on monarch conservation, and conduct research—including facilitating community science projects like the Western Monarch Thanksgiving Count and the Western Monarch Milkweed Mapper. Conservation of eastern monarchs—which breed east of the Rocky Mountains and overwinter in central Mexico—is an important part of Xerces' work across the Midwest, Southern Great Plains, Northeast, and Southeast. Learn more about their needs and what we're doing to help. A significant focus of our monarch conservation efforts focuses on western monarchs, which breed west of the Rocky Mountains and generally overwinter in coastal California. Western monarchs are less well-studied—yet they are at a greater risk of extinction as their eastern counterparts. A set of rapid-response conservation actions that, if applied immediately, can help western monarchs. The goal of this call to action is to identify actions that can be implemented in the short-term, to avoid a total collapse of the western monarch migration and set the stage for longer-term efforts to have time to start making a difference.
Imagine being able to take a photograph that goes 13.4 billion years into the past. That was exactly what Yale researchers were able to do using the NASA's Hubble Telescope. Yale led a team of researchers from the Space Telescope Science Institute and the University of California-Santa Cruz to investigate galaxy GN-z11. After a 13.4 billion year journey through the universe, the light from the galaxy has made it to Earth. It is believed the light from the galaxy originated just 400 million years after the Big Bang. GN-z11 is in the constellation Ursa Major, otherwise known as the Big Dipper. “We’ve taken a major step back in time, beyond what we’d ever expected to be able to do with Hubble. We see the galaxy at a time when the universe was only 3% of its current age, very close to the end of the so-called Dark Ages of the universe,” said Yale astronomer Pascal Oesch, the principal investigator. The galaxy is 25 times smaller than the Milky Way, but is rapidly growing - or shall we say 'was' rapidly growing. Thought the galaxy is more than 13 billion years old, we're only seeing it as an infant galaxy. “It’s amazing that a galaxy so massive existed only 200 to 300 million years after the very first stars started to form,” Garth Illingworth of the University of California-Santa Cruz said. “It takes really fast growth, producing stars at a huge rate, to have formed a galaxy that is a billion solar masses (one solar mass is equal to the mass of the Sun) so soon.”
Mines use toxic chemicals including cyanide, mercury, and sulphuric acid, to separate metal from ore. The chemicals used in the processing are generally recycled, however residues may remain in the tailings, which in developing countries are often dumped directly into lakes or rivers with devastating consequences. The accidental spillage of processing chemicals can also have a serious impact on the environment. For example, at the Baia Mare mine in Romania cyanide is used to extract gold from slurry. In January 2000 a dam containing tens of thousands of tonnes of slurry burst, poisoning the local river with cyanide and heavy metals. Up to 100 tonnes of cyanide were released into the river, a tributary of the Danube. The drinking water supply for more than 2 million people was affected. Within hours, dead fi sh were seen washed up along the river.
A blister is a localized collection of fluid causing a bump (a raised area) of the skin and separating it into an upper and lower layer. The fluid collected between the two layers of skin can be blood, lymph, or serum (the watery, clear portion of the blood). Most blisters are on the feet or hands. Blisters can be a result of burns, sunburns, friction (e.g. from shoes), pressure, or hard impacts. Spanking with certain implements, such as paddles with holes drilled through, can cause blisters. Blisters from paddling develop when the paddle stroke compresses the skin, forcing fluid out of the tissue and into those areas where the holes are drilled through the paddle, resulting in circular blisters. Paddling which damages capillaries can also cause blisters to form, or contribute to their formation. A blister is different from a welt, which is also a raised area of the skin. In a welt, the skin is not separated in two layers, and the fluid remains in the tissue, rather than forming a pool as in a blister. A blister, and the area around it, is often reddened from whatever caused the blister. Blisters are painful to the touch (especially to friction) and can pop, resulting in an open wound that may well need treatment such as disinfection, bandaging, and/or a sticking plaster. Avoid peeling any skin off a popped blister. If a blister is deliberately punctured to drain the fluid (which can relief the pressure, but also cause infections), a sterile needle should be used. - How to Care for a Blister on eHow
Riemann Sums for Functions of Two Variables Visualize and calculate a Riemann sum for a real–valued function of two real variables. The x and y axes are partitioned into subintervals of equal width. Set the point on each subrectangle where the function is evaluated to determine the height of the rectangular solid constructed over that subrectangle. This Demonstration is meant for students of multivariable calculus. It illustrates the concept of a Riemann sum for a real–valued function of two real variables. Choose one of four functions. Then you can freely select a uniform partition of either the x or y axis into 5, 10, 20, or 40 parts. You may also select the point on each subrectangle at which the function is evaluated (to determine the height of the rectangular solid to be constructed over that subrectangle). Initially, the function is evaluated at the center. This feature is included to show that as the partition becomes finer, the choice of this point becomes less consequential, suggesting that in the limit it simply does not matter.
An assumption bridges the gap between an argument’s evidence and conclusion. It’s a piece of support that isn’t explicitly stated, but that is required for the conclusion to remain valid. When a question asks you to find an author’s assumption, it’s asking you to find the statement without which the argument falls apart To test whether a statement is necessarily assumed by an author, we can employ the Denial Test. Here’s how it works: Simply deny or negate the statement and see if the argument falls apart. If it does, that choice is a necessary assumption. If, on the other hand, the argument is unaffected, the choice is wrong. Consider this simple stimulus: Allyson plays volleyball for Central High School. Therefore, Allyson must be over 6 feet tall. You should recognize the second sentence as the conclusion and the first sentence as the evidence for it. But is the argument complete? Obviously not. The piece that’s missing-the unstated link between the evidence and conclusion-is the assumption, and you could probably prephrase this one pretty easily: All volleyball players for Central High School are over 6 feet tall. Is this an assumption really necessary to the argument? Let’s negate it using the Denial Test. What if it’s not true that all volleyball players for Central High are taller than 6 feet? Can we still logically conclude that Allyson must be taller than 6 feet? No, we can’t. Sure, she might be, but she also might not be. By denying the statement, then, the argument falls to pieces; it is no longer valid. And that’s our conclusive proof that the statement above is a necessary assumption of this argument. So, we can use the Denial Test to chick whether a statement is an assumption, but what if we haven’t a clue about what the assumption is? Is there a way to track it down? Sure enough, there is? Compare the ideas in the evidence with those in the conclusion. If the conclusion has an idea (an important word) but the evidence does not, then you’ve found an assumption. A new idea cannot occur in the conclusion, so there must be an assumption about this idea. Every idea in the conclusion need support-that is, evidence. While it may not be quite clear what the assumption is, knowing something about it allows us to prephrase and eliminate choices. As we’ve just seen, you can often prephrase the answer to an Assumption question. By previewing the question stem, you’ll know what to look for. And stimuli for Assumption questions just “feel” as if they’re missing something. Often, the answer will jump out at you, as it did here. But in more difficult Assumption questions, it might not be so obvious. Either way, use the Denial Test to quickly check whichever choice seems correct. Sample Question Stems Assumption questions are worded in some of the following ways: - Which one of the following is assumed by the author? - Upon which one of the following assumptions does the author rely? - The argument depends on the assumption that? - Which of the following, if added to the passage, will make the conclusion logical? - The validity of the argument depends on which one of the following? - The argument presupposes which one of the following?
Elementary Learning Standards Ohio's Learning Standards, model curricula and assessments make up the state's education system that work together to help students learn. The standards explain the knowledge and skills students are learning in pre-kindergarten through 12th grade. Ohio's Learning Standards emphasize skills like critical thinking and problem solving - qualities most sought by today's employers. By teaching students to apply these skills to what they are studying in school, we can make sure they are on track to graduate from high school and enjoy success in college, careers and life.
Curriculum >> Key Stage 4 >> French At Dukhan English School we offer our students the opportunity to study French as a Modern Foreign Language to provide them with an opening to other cultures in a rapidly changing world. This should foster student's curiosity and deepen their understanding of the world. The teaching should also enable them to express their ideas and thoughts in another language. Therefore, learning a foreign language prepares our children for life in a modern world where work and activities increasingly involve using languages. Languages are part of the cultural richness of our society and the world in which we live and work. They contribute to mutual understanding, a sense of global citizenship and personal fulfillment. This promotes the appreciation of different countries, cultures, communities and people. Communicating in another language is a lifelong skill for education, employment, and leisure throughout the world. Learning languages gives pupils opportunities to develop a variety of skills and express themselves with increasing confidence, independence and creativity. Therefore, our aim is to help students: DEEPEN their intercultural understanding, BUILD vocabulary and communication skills, UNDERSTAND and use language context to deduce meaning, PRACTISE their skills in a stimulating and interactive way, BOOST their confidence, accuracy and exams results, and LOVE learning languages. The GCSE Edexcel course in French encourages pupils to develop an understanding of the spoken and written forms of the language in a range of contexts. It allows pupils to develop the ability to communicate effectively in the target language using a range of vocabulary and structures. The course teaches pupils to understand the rules of grammar and be able to apply them. It also encourages them to discover countries and communities where these languages are spoken. The topics covered in the GCSE are : Sport and Leisure, Media and Culture, Travel, Tourism and Business Work and Employment. The aim to develop abilities in the four attainment targets are related directly to the specifications for GCSEs for MFL. These can be broken down into strands of MFL teaching. Students can develop their understanding in a wide range of topics, factual and imaginative. Also they learn to work out the meaning of new words. Students learn to talk fluently, confidently and spontaneously about many topics with a good pronunciation and intonation. Students aim to understand texts about people's feeling, opinions, and points of view, as well as more factual information. They learn to make a less frequent use of the dictionary to deduce meaning when dealing with new and complex vocabulary. Students learn to use a range of tenses, vocabulary and structures to make what they write as varied and interesting as possible. We aim to help every student achieve the highest grade of which he or she is capable so that they become confident linguist in their future studies and working lives. We assess students on a regular basis and their progression is measured using GCSE grade descriptors. The examination consists of four units, listening, speaking, reading and writing. Speaking and writing are assessed internally by the teacher and then moderated by Edexcel. They can be taken at any time during the two year course. Listening and reading skills are assessed by Edexcel at the end of Year 11. Knowing Modern Languages offers job opportunities in an array of areas such as Teaching, Diplomacy, Import/Export Sales, Hotel Management, Engineering, Banking, Journalism, Broadcasting, Travel and Marketing.
On a one-dimensional board with n + m + 1 cells, there are n counters in the first n cells representing Toads and m counters in the last m cells representing Frogs. The empty cell is represented by X. For illustration, if n = 4 and m = 3, then the problem is as depicted below: T T T T X F F F Toads and Frogs take turns moving. Moves consist of sliding a Toad or Frog into the empty cell or jumping over one opposing creature into the empty cell. (Toads cannot jump over themselves and neither can Frogs.) Toads can only move rightward and Frogs can only move leftward. What is the total number of moves (i.e. jumps and slides) required for the toads to switch their positions with the frogs as depicted below: F F F X T T T T ALGORITHM: To solve the problem, whenever there is a choice between a slide and a jump, the jump must be made. ILLUSTRATION: Consider n = 2 toads and m = 1 frog, then the algorithm could proceed as follows: T T X F T X T F Slide T F T X Jump T F X T Slide X F T T Jump F X T T Slide Hence, a total of five moves is required for n = 2 toads and m = 1 frog.
Plumbing math must have many applications available for calculations on different projects. Plumbing Math – Learning Outcomes After completing this module, you will be able to: • Recognize the importance of knowing basic math skills that will help you to do plumbing tasks • Apply math operations such as addition, subtraction, multiplication, division, percentage, fractions, conversions to calculate pipe length • Describe the terms associated with plumbing math • Discuss the general process for measuring pipes • Identify the difference between thread makeup and fitting allowance in measuring pipe length Log in to save your progress and obtain a certificate in Alison’s free Diploma in Plumbing Studies online course Sign up to save your progress and obtain a certificate in Alison’s free Diploma in Plumbing Studies online course Please enter you email address and we will mail you a link to reset your password.
Extinct and Endangered Plants and Animals Why did dinosaurs become extinct? How does a mastodon differ from a mammoth? Although the words are sometimes used interchangeably, the mammoth and the mastodon were two different animals. The mastodon seems to have appeared first, while a side branch may have led to the mammoth. The mastodon lived in Africa, Europe, Asia, and North and South America. It appeared in the Oligocene epoch (25 to 38 million years ago) and survived until less than one million years ago. It stood a maximum of 10 feet (3 meters) tall and was covered with dense woolly hair. Its tusks were aligned straight forward and were nearly parallel to each other. The mammoth evolved less than two million years ago and died out about ten thousand years ago. It lived in North America, Europe, and Asia. Like the mastodon, the mammoth was covered with dense, woolly hair, with a long, coarse layer of outer hair to protect it from the cold. It was somewhat larger than the mastodon, standing 9 to 15 feet (2.7 to 4.5 meters). The mammoth’s tusks tended to spiral outward, then up. The gradual warming of Earth’s climate and the change in environment were probably primary factors in the animals’ extinction. Early man killed many of them as well, perhaps hastening the process. There are many theories as to why dinosaurs disappeared from Earth about 65 million years ago. Scientists debate whether dinosaurs became extinct gradually or all at once. The gradualists believe that the dinosaur population steadily declined at the end of Cretaceous Period. Numerous reasons have been proposed for this. Some claim the dinosaurs’ extinction was caused by biological changes that made them less competitive with other organisms, especially the mammals that were just beginning to appear. Overpopulation has been argued, as has the theory that mammals ate too many dinosaur eggs for the animals to reproduce themselves. Others believe that disease—everything from rickets to constipation—wiped them out. Changes in climate, continental drift, volcanic eruptions, and shifts in Earth’s axis, orbit, and/or magnetic field have also been held responsible. The catastrophists argue that a single disastrous event caused the extinction not only of the dinosaurs but also of a large number of other species that coexisted with them. In 1980, American physicist Luis Alvarez (1911–1988) and his geologist son, Walter Alvarez (1940–), proposed that a large comet or meteoroid struck Earth 65 million years ago. They pointed out that there is a high concentration of the element iridium in the sediments at the boundary between the Cretaceous and Tertiary Periods. Iridium is rare on Earth, so the only source of such a large amount of it had to be outer space. This iridium anomaly has since been discovered at over 50 sites around the world. In 1990, tiny glass fragments, which could have been caused by the extreme heat of an impact, were identified in Haiti. A 110-mile (177-kilometer) wide crater in the Yucatan Peninsula, long covered by sediments, has been dated to 64.98 million years ago, making it a leading candidate for the site of this impact. A hit by a large extraterrestrial object, perhaps as much as 6 miles (9.3 kilometers) wide, would have had a catastrophic effect upon the world’s climate. Huge amounts of dust and debris would have been thrown into the atmosphere, reducing the amount of sunlight reaching the surface. Heat from the blast may also have caused large forest fires, which would have added smoke and ash to the air. Lack of sunlight would kill off plants and have a domino-like effect on other organisms in the food chain, including the dinosaurs. It is possible that the reason for the dinosaurs’ extinction may have been a combination of both theories. The dinosaurs may have been gradually declining, for whatever reason. The impact of a large object from space merely delivered the final devastating blow. The fact that dinosaurs became extinct has been cited as proof of their inferiority and that they were evolutionary failures. However, these animals flourished for 150 million years. By comparison, the earliest ancestors of humanity appeared only about three million years ago. Humans have a long way to go before they can claim the same sort of success as the dinosaurs.
\|\|Poets, Lyricists and Creative Writers - Write fiction or nonfiction prose, such as short stories, novels, biographies, articles, descriptive or critical analyses, and essays. - Develop factors such as themes, plots, characterizations, psychological analyses, historical environments, action, and dialogue to create material. - Prepare works in appropriate format for publication, and send them to publishers or producers. - Revise written material to meet personal standards and to satisfy needs of clients, publishers, directors, or producers. - Plan project arrangements or outlines, and organize material accordingly. - Write narrative, dramatic, lyric, or other types of poetry for publication. - Adapt text to accommodate musical requirements of composers and singers. - Write words to fit musical compositions, including lyrics for operas, musical plays, and choral works. - Write humorous material for publication, or for performances such as comedy routines, gags, and comedy shows. - Read copy or proof to detect and correct errors in spelling, punctuation, and syntax. - Read, evaluate and edit manuscripts or other materials submitted for publication and confer with authors regarding changes in content, style or organization, or publication. - Prepare, rewrite and edit copy to improve readability, or supervise others who do this work. - Review and approve proofs submitted by composing room prior to publication production. - Make manuscript acceptance or revision recommendations to the publisher. - Read material to determine index items and arrange them alphabetically or topically, indicating page or chapter location. - Organize material and complete writing assignment according to set standards regarding order, clarity, conciseness, style, and terminology. - Edit, standardize, or make changes to material prepared by other writers or establishment personnel. - Review published materials and recommend revisions or changes in scope, format, content, and methods of reproduction and binding. \|\|Radio and Television Announcers - Prepare and deliver news, sports, or weather reports, gathering and rewriting material so that it will convey required information and fit specific time slots. - Write and edit video and scripts for broadcasts. \|\|Reporters and Correspondents - Revise work to meet editorial approval or to fit time or space requirements. - Review written, audio, or video copy and correct errors in content, grammar, or punctuation, following prescribed editorial style and formatting guidelines.
In vector calculus, the curl is a vector operator that describes the insignificant rotation of a 3-dimensional vector field. If the vector field represents the flow velocity of a moving fluid, then the curl is the circulation density of the fluid. The curl measures the degree to which the fluid is rotating about a given point, with whirlpools and tornadoes being extreme examples. In three dimensional space, if the appropriate vector function of a point is V→ (x, y, z) = (v1 î + v2 ĵ + v3 ƙ), then a vector along the rotational axis is obtained by the cross product of the operator ∆ and V. This type of product is called curl. Physical properties of Curl - If f (x, y, z) has continuous second order partial derivatives then curl (∆f = 0→). This is easy enough to check by plugging into the definition of the derivative. - If F→ is a conservative vector field then Curl, F→ = 0→. This is a direct result of what it means to be a conservative vector field and the previous fact. - If F→ is defined on all of Ɍ3 whose components have continuous first-order partial derivative and Curl F→ = 0→ then F→ is a conservative vector field.
Intriguing New Theory Might Explain the Fate of Easter Island's Civilization Standing up to 33 feet high and weighing 81 tons, the huge moai statues of Easter Island (Rapa Nui) are the most recognizable artifacts of a thriving civilization that peaked at the middle of the last millennium. For hundreds of years, Polynesian peoples lived on the small island 2300 miles west of Chile and developed a complex culture. By the 1700s, when Europeans first arrived, much of the society was decimated. For years, scientists thought they knew why—but fresh archaeological evidence has provided an alternative theory. The Journal of Pacific Archaeology published a paper [PDF] this week contradicting the commonly held belief that, in the 1600s, Rapa Nui's inhabitants descended into a Lord of the Flies–like era of infighting and violence as a result of dwindling resources. According to new research, the island’s population may not have devolved into barbarism. Instead, they were collaborating on toolmaking. University of Queensland archaeologist Dale Simpson, Jr. theorized that the raw materials used in the carving tools would reveal clues about the dynamics of the community. He and his colleagues collected 17 tools found near the moai, including axe-like toki. Using a mass spectrometer to analyze the chemical composition of the tools and samples from stone quarries on the island, Simpson and his colleagues found that most of the toki came from a single quarry. Simpson believes this is evidence that Rapa Nui's people had not fallen into violent conflict, but were instead sharing resources—or at least allowing one another access to a favorite quarry for tool production. If the islanders were split into factions, it’s unlikely that whoever was controlling the quarry would permit rivals to make use of it. If accurate, it would join other recent theories that are drawing a revised picture of Rapa Nui's civilization. Explorers once described a surplus of spear-like objects presumably used for combat, but modern researchers examining the tools (called mata’a) in 2015 found that their surfaces were too blunt to pierce skin and were probably used for tilling soil. While Simpson's take on the newly discovered carving tools is an intriguing theory, researchers aren't ready to rewrite history just yet. Other scholars, including study co-author Jo Anne Van Tilburg, point out that raw materials for the tools could have been seized by force or some form of coercion. More research will be needed to see if Simpson’s new theory holds up. If it does, it would present a new wrinkle in the storied history of Rapa Nui.
Prejudice and Discrimination - Define and distinguish among prejudice, stereotypes, and discrimination - Provide examples of prejudice, stereotypes, and discrimination - Explain why prejudice and discrimination exist Human conflict can result in crime, war, and mass murder, such as genocide. Prejudice and discrimination often are root causes of human conflict, which explains how strangers come to hate one another to the extreme of causing others harm. Prejudice and discrimination affect everyone. In this section we will examine the definitions of prejudice and discrimination, examples of these concepts, and causes of these biases. Section 2: UNDERSTANDING PREJUDICE AND DISCRIMINATION As we discussed in the opening story of Trayvon Martin, humans are very diverse and although we share many similarities, we also have many differences. The social groups we belong to help form our identities (Tajfel, 1974). These differences may be difficult for some people to reconcile, which may lead to prejudice toward people who are different. Prejudice is a negative attitude and feeling toward an individual based solely on one’s membership in a particular social group (Allport, 1954; Brown, 2010). Prejudice is common against people who are members of an unfamiliar cultural group. Thus, certain types of education, contact, interactions, and building relationships with members of different cultural groups can reduce the tendency toward prejudice. In fact, simply imagining interacting with members of different cultural groups might affect prejudice. Indeed, when experimental participants were asked to imagine themselves positively interacting with someone from a different group, this led to an increased positive attitude toward the other group and an increase in positive traits associated with the other group. Furthermore, imagined social interaction can reduce anxiety associated with inter-group interactions (Crisp & Turner, 2009). What are some examples of social groups that you belong to that contribute to your identity? Social groups can include gender, race, ethnicity, nationality, social class, religion, sexual orientation, profession, and many more. And, as is true for social roles, you can simultaneously be a member of more than one social group. An example of prejudice is having a negative attitude toward people who are not born in the United States. Although people holding this prejudiced attitude do not know all people who were not born in the United States, they dislike them due to their status as foreigners. Can you think of a prejudiced attitude you have held toward a group of people? How did your prejudice develop? Prejudice often begins in the form of a stereotype—that is, a specific belief or assumption about individuals based solely on their membership in a group, regardless of their individual characteristics. Stereotypes become overgeneralized and applied to all members of a group. For example, someone holding prejudiced attitudes toward older adults, may believe that older adults are slow and incompetent (Cuddy, Norton, & Fiske, 2005; Nelson, 2004). We cannot possibly know each individual person of advanced age to know that all older adults are slow and incompetent. Therefore, this negative belief is overgeneralized to all members of the group, even though many of the individual group members may in fact be spry and intelligent. Another example of a well-known stereotype involves beliefs about racial differences among athletes. As Hodge, Burden, Robinson, and Bennett (2008) point out, Black male athletes are often believed to be more athletic, yet less intelligent, than their White male counterparts. These beliefs persist despite a number of high profile examples to the contrary. Sadly, such beliefs often influence how these athletes are treated by others and how they view themselves and their own capabilities. Whether or not you agree with a stereotype, stereotypes are generally well-known within in a given culture (Devine, 1989). Sometimes people will act on their prejudiced attitudes toward a group of people, and this behavior is known as discrimination. Discrimination is negative action toward an individual as a result of one’s membership in a particular group (Allport, 1954; Dovidio & Gaertner, 2004). As a result of holding negative beliefs (stereotypes) and negative attitudes (prejudice) about a particular group, people often treat the target of prejudice poorly, such as excluding older adults from their circle of friends. Table summarizes the characteristics of stereotypes, prejudice, and discrimination. Have you ever been the target of discrimination? If so, how did this negative treatment make you feel? \|Stereotype\|\|Cognitive; thoughts about people\|\|Overgeneralized beliefs about people may lead to prejudice.\|\|“Yankees fans are arrogant and obnoxious.”\| \|Prejudice\|\|Affective; feelings about people, both positive and negative\|\|Feelings may influence treatment of others, leading to discrimination.\|\|“I hate Yankees fans; they make me angry.”\| \|Discrimination\|\|Behavior; positive or negative treatment of others\|\|Holding stereotypes and harboring prejudice may lead to excluding, avoiding, and biased treatment of group members.\|\|“I would never hire nor become friends with a person if I knew he or she were a Yankees fan.”\| So far, we’ve discussed stereotypes, prejudice, and discrimination as negative thoughts, feelings, and behaviors because these are typically the most problematic. However, it is important to also point out that people can hold positive thoughts, feelings, and behaviors toward individuals based on group membership; for example, they would show preferential treatment for people who are like themselves—that is, who share the same gender, race, or favorite sports team. This video demonstrates the concepts of prejudice, stereotypes, and discrimination. In the video, a social experiment is conducted in a park where three people try to steal a bike out in the open. The race and gender of the thief is varied: a White male teenager, a Black male teenager, and a White female. Does anyone try to stop them? The treatment of the teenagers in the video demonstrates the concept of racism. Section 3: TYPES OF PREJUDICE AND DISCRIMINATION When we meet strangers we automatically process three pieces of information about them: their race, gender, and age (Ito & Urland, 2003). Why are these aspects of an unfamiliar person so important? Why don’t we instead notice whether their eyes are friendly, whether they are smiling, their height, the type of clothes they are wearing? Although these secondary characteristics are important in forming a first impression of a stranger, the social categories of race, gender, and age provide a wealth of information about an individual. This information, however, often is based on stereotypes. We may have different expectations of strangers depending on their race, gender, and age. What stereotypes and prejudices do you hold about people who are from a race, gender, and age group different from your own? Racism is prejudice and discrimination against an individual based solely on one’s membership in a specific racial group (such as toward African Americans, Asian Americans, Latinos, Native Americans, European Americans). What are some stereotypes of various racial or ethnic groups? Research suggests cultural stereotypes for Asian Americans include cold, sly, and intelligent; for Latinos, cold and unintelligent; for European Americans, cold and intelligent; and for African Americans, aggressive, athletic, and more likely to be law breakers (Devine & Elliot, 1995; Fiske, Cuddy, Glick, & Xu, 2002; Sommers & Ellsworth, 2000; Dixon & Linz, 2000). Racism exists for many racial and ethnic groups. For example, Blacks are significantly more likely to have their vehicles searched during traffic stops than Whites, particularly when Blacks are driving in predominately White neighborhoods, (a phenomenon often termed “DWB,” or “driving while Black.”) (Rojek, Rosenfeld, & Decker, 2012) Mexican Americans and other Latino groups also are targets of racism from the police and other members of the community. For example, when purchasing items with a personal check, Latino shoppers are more likely than White shoppers to be asked to show formal identification (Dovidio et al., 2010). In one case of alleged harassment by the police, several East Haven, Connecticut, police officers were arrested on federal charges due to reportedly continued harassment and brutalization of Latinos. When the accusations came out, the mayor of East Haven was asked, “What are you doing for the Latino community today?” The Mayor responded, “I might have tacos when I go home, I’m not quite sure yet” (“East Haven Mayor,” 2012) This statement undermines the important issue of racial profiling and police harassment of Latinos, while belittling Latino culture by emphasizing an interest in a food product stereotypically associated with Latinos. Racism is prevalent toward many other groups in the United States including Native Americans, Arab Americans, Jewish Americans, and Asian Americans. Have you witnessed racism toward any of these racial or ethnic groups? Are you aware of racism in your community? One reason modern forms of racism, and prejudice in general, are hard to detect is related to the dual attitudes model (Wilson, Lindsey, & Schooler, 2000). Humans have two forms of attitudes: explicit attitudes, which are conscious and controllable, and implicit attitudes, which are unconscious and uncontrollable (Devine, 1989; Olson & Fazio, 2003). Because holding egalitarian views is socially desirable (Plant & Devine, 1998), most people do not show extreme racial bias or other prejudices on measures of their explicit attitudes. However, measures of implicit attitudes often show evidence of mild to strong racial bias or other prejudices (Greenwald, McGee, & Schwartz, 1998; Olson & Fazio, 2003). Sexism is prejudice and discrimination toward individuals based on their sex. Typically, sexism takes the form of men holding biases against women, but either sex can show sexism toward their own or their opposite sex. Like racism, sexism may be subtle and difficult to detect. Common forms of sexism in modern society include gender role expectations, such as expecting women to be the caretakers of the household. Sexism also includes people’s expectations for how members of a gender group should behave. For example, women are expected to be friendly, passive, and nurturing, and when women behave in an unfriendly, assertive, or neglectful manner they often are disliked for violating their gender role (Rudman, 1998). Research by Laurie Rudman (1998) finds that when female job applicants self-promote, they are likely to be viewed as competent, but they may be disliked and are less likely to be hired because they violated gender expectations for modesty. Sexism can exist on a societal level such as in hiring, employment opportunities, and education. Women are less likely to be hired or promoted in male-dominated professions such as engineering, aviation, and construction (Figure) (Blau, Ferber, & Winkler, 2010; Ceci & Williams, 2011). Have you ever experienced or witnessed sexism? Think about your family members’ jobs or careers. Why do you think there are differences in the jobs women and men have, such as more women nurses but more male surgeons (Betz, 2008)? People often form judgments and hold expectations about people based on their age. These judgments and expectations can lead to ageism, or prejudice and discrimination toward individuals based solely on their age. Typically, ageism occurs against older adults, but ageism also can occur toward younger adults. Think of expectations you hold for older adults. How could someone’s expectations influence the feelings they hold toward individuals from older age groups? Ageism is widespread in U.S. culture (Nosek, 2005), and a common ageist attitude toward older adults is that they are incompetent, physically weak, and slow (Greenberg, Schimel, & Martens, 2002) and some people consider older adults less attractive. Some cultures, however, including some Asian, Latino, and African American cultures, both outside and within the United States afford older adults respect and honor. Ageism can also occur toward younger adults. What expectations do you hold toward younger people? Does society expect younger adults to be immature and irresponsible? How might these two forms of ageism affect a younger and older adult who are applying for a sales clerk position? Another form of prejudice is homophobia: prejudice and discrimination of individuals based solely on their sexual orientation. Like ageism, homophobia is a widespread prejudice in U.S. society that is tolerated by many people (Herek & McLemore, 2013; Nosek, 2005). Negative feelings often result in discrimination, such as the exclusion of lesbian, gay, bisexual, and transgender (LGBT) people from social groups and the avoidance of LGBT neighbors and co-workers. This discrimination also extends to employers deliberately declining to hire qualified LGBT job applicants. Have you experienced or witnessed homophobia? If so, what stereotypes, prejudiced attitudes, and discrimination were evident? Research into Homophobia Some people are quite passionate in their hatred for nonheterosexuals in our society. In some cases, people have been tortured and/or murdered simply because they were not heterosexual. This passionate response has led some researchers to question what motives might exist for homophobic people. Adams, Wright, & Lohr (1996) conducted a study investigating this issue and their results were quite an eye-opener. In this experiment, male college students were given a scale that assessed how homophobic they were; those with extreme scores were recruited to participate in the experiment. In the end, 64 men agreed to participate and were split into 2 groups: homophobic men and nonhomophobic men. Both groups of men were fitted with a penile plethysmograph, an instrument that measures changes in blood flow to the penis and serves as an objective measurement of sexual arousal. All men were shown segments of sexually explicit videos. One of these videos involved a sexual interaction between a man and a woman (heterosexual clip). One video displayed two females engaged in a sexual interaction (homosexual female clip), and the final video displayed two men engaged in a sexual interaction (homosexual male clip). Changes in penile tumescence were recorded during all three clips, and a subjective measurement of sexual arousal was also obtained. While both groups of men became sexually aroused to the heterosexual and female homosexual video clips, only those men who were identified as homophobic showed sexual arousal to the homosexual male video clip. While all men reported that their erections indicated arousal for the heterosexual and female homosexual clips, the homophobic men indicated that they were not sexually aroused (despite their erections) to the male homosexual clips. Adams et al. (1996) suggest that these findings may indicate that homophobia is related to homosexual arousal that the homophobic individuals either deny or are unaware. Section 4: WHY DO PREJUDICE AND DISCRIMINATION EXIST? Prejudice and discrimination persist in society due to social learning and conformity to social norms. Children learn prejudiced attitudes and beliefs from society: their parents, teachers, friends, the media, and other sources of socialization, such as Facebook (O’Keeffe & Clarke-Pearson, 2011). If certain types of prejudice and discrimination are acceptable in a society, there may be normative pressures to conform and share those prejudiced beliefs, attitudes, and behaviors. For example, public and private schools are still somewhat segregated by social class. Historically, only children from wealthy families could afford to attend private schools, whereas children from middle- and low-income families typically attended public schools. If a child from a low-income family received a merit scholarship to attend a private school, how might the child be treated by classmates? Can you recall a time when you held prejudiced attitudes or beliefs or acted in a discriminatory manner because your group of friends expected you to? Section 5: STEREOTYPES AND SELF-FULFILLING PROPHECY When we hold a stereotype about a person, we have expectations that he or she will fulfill that stereotype. A self-fulfilling prophecy is an expectation held by a person that alters his or her behavior in a way that tends to make it true. When we hold stereotypes about a person, we tend to treat the person according to our expectations. This treatment can influence the person to act according to our stereotypic expectations, thus confirming our stereotypic beliefs. Research by Rosenthal and Jacobson (1968) found that disadvantaged students whose teachers expected them to perform well had higher grades than disadvantaged students whose teachers expected them to do poorly. Consider this example of cause and effect in a self-fulfilling prophecy: If an employer expects an openly gay male job applicant to be incompetent, the potential employer might treat the applicant negatively during the interview by engaging in less conversation, making little eye contact, and generally behaving coldly toward the applicant (Hebl, Foster, Mannix, & Dovidio, 2002). In turn, the job applicant will perceive that the potential employer dislikes him, and he will respond by giving shorter responses to interview questions, making less eye contact, and generally disengaging from the interview. After the interview, the employer will reflect on the applicant’s behavior, which seemed cold and distant, and the employer will conclude, based on the applicant’s poor performance during the interview, that the applicant was in fact incompetent. Thus, the employer’s stereotype—gay men are incompetent and do not make good employees—is reinforced. Do you think this job applicant is likely to be hired? Treating individuals according to stereotypic beliefs can lead to prejudice and discrimination. Another dynamic that can reinforce stereotypes is confirmation bias. When interacting with the target of our prejudice, we tend to pay attention to information that is consistent with our stereotypic expectations and ignore information that is inconsistent with our expectations. In this process, known as confirmation bias, we seek out information that supports our stereotypes and ignore information that is inconsistent with our stereotypes (Wason & Johnson-Laird, 1972). In the job interview example, the employer may not have noticed that the job applicant was friendly and engaging, and that he provided competent responses to the interview questions in the beginning of the interview. Instead, the employer focused on the job applicant’s performance in the later part of the interview, after the applicant changed his demeanor and behavior to match the interviewer’s negative treatment. Have you ever fallen prey to the self-fulfilling prophecy or confirmation bias, either as the source or target of such bias? How might we stop the cycle of the self-fulfilling prophecy? Social class stereotypes of individuals tend to arise when information about the individual is ambiguous. If information is unambiguous, stereotypes do not tend to arise (Baron et al., 1995). Section 6: IN-GROUPS AND OUT-GROUPS As discussed previously in this section, we all belong to a gender, race, age, and social economic group. These groups provide a powerful source of our identity and self-esteem (Tajfel & Turner, 1979). These groups serve as our in-groups. An in-group is a group that we identify with or see ourselves as belonging to. A group that we don’t belong to, or an out-group, is a group that we view as fundamentally different from us. For example, if you are female, your gender in-group includes all females, and your gender out-group includes all males (Figure). People often view gender groups as being fundamentally different from each other in personality traits, characteristics, social roles, and interests. Because we often feel a strong sense of belonging and emotional connection to our in-groups, we develop in-group bias: a preference for our own group over other groups. This in-group bias can result in prejudice and discrimination because the out-group is perceived as different and is less preferred than our in-group. Despite the group dynamics that seem only to push groups toward conflict, there are forces that promote reconciliation between groups: the expression of empathy, of acknowledgment of past suffering on both sides, and the halt of destructive behaviors. One function of prejudice is to help us feel good about ourselves and maintain a positive self-concept. This need to feel good about ourselves extends to our in-groups: We want to feel good and protect our in-groups. We seek to resolve threats individually and at the in-group level. This often happens by blaming an out-group for the problem. Scapegoating is the act of blaming an out-group when the in-group experiences frustration or is blocked from obtaining a goal (Allport, 1954). Section 7: Summary As diverse individuals, humans can experience conflict when interacting with people who are different from each other. Prejudice, or negative feelings and evaluations, is common when people are from a different social group (i.e., out-group). Negative attitudes toward out-groups can lead to discrimination. Prejudice and discrimination against others can be based on gender, race, ethnicity, social class, sexual orientation, or a variety of other social identities. In-group’s who feel threatened may blame the out-groups for their plight, thus using the out-group as a scapegoat for their frustration. Section 8: Review Questions Prejudice is to ________ as discrimination is to ________. - feelings; behavior - thoughts; feelings - feelings; thoughts - behavior; feelings Which of the following is not a type of prejudice? ________ occurs when the out-group is blamed for the in-group’s frustration. - in-group bias When we seek out information that supports our stereotypes we are engaged in ________. - confirmation bias - self-fulfilling prophecy - in-group bias Section 9: Critical Thinking Questions Some people seem more willing to openly display prejudice regarding sexual orientation than prejudice regarding race and gender. Speculate on why this might be. In the United States, many people believe that sexual orientation is a choice, and there is some debate in the research literature as to the extent sexual orientation is biological or influenced by social factors. Because race and gender are not chosen, many Americans believe it is unfair to negatively judge women or racial minority groups for a characteristic that is determined by genetics. In addition, many people in the United States practice religions that believe homosexuality is wrong. When people blame a scapegoat, how do you think they choose evidence to support the blame? One way in which they might do this is to selectively attend to information that would bolster their argument. Furthermore, they may actively seek out information to confirm their assertions. Section 10: Personal Application Questions Give an example when you felt that someone was prejudiced against you. What do you think caused this attitude? Did this person display any discrimination behaviors and, if so, how? Give an example when you felt prejudiced against someone else. How did you discriminate against them? Why do you think you did this?
Use these first grade homework worksheets for extra practice with sight words. Our reproducibles are fun for students to complete and easy to do at home. The directions on these pages are simple, and no extra information is needed from the classroom. A parent or family helper can simply read the instructions to their child and then watch the learning and fun begin! Don't miss the important tips in the yellow box below. On this engaging page, the student strings together letters to form sight words. Then he uses the words he makes to complete sentences at the bottom of the page. Download the printable version. On this page, the student must find a color word hidden inside a group of letters. He will write the letter twice, and also use that color to shade the crayon. This first grade worksheet gives lots of valuable repetition, while connecting words and ideas. Download the printable You'll find lots of other pages on our site that are suitable for first grade homework worksheets. Here are just a few examples: First grade phonics worksheets - 5 free printables provide practice with simple short vowel words. Start the Picture and Winter Fun - 2 worksheets for first grade practice with beginning consonants and consonant blends practice - 3 printable worksheets to reinforce spelling and simple addition and subtraction facts. The fun twists I've added will make your kids want finish each page correctly. Paw Print Addition, "Bear"-y Good Subtraction and more! Word Scrambles - 2 worksheets with sets of familiar words to boost kids' vocabulary and spelling skills
In this series, we thought it might be fun to show you some extinct animal kinds—varieties that Noah interacted with that we do not. We’ve already covered five different mammal kinds: entelodonts, macraucheniids, barylambids, chalicotheres, and unitatheres. Now we present you with some reptiles. The first reptile in our series is the spinosaur kind. The family Spinosauridae consisted of a unique group of theropod dinosaurs with crocodile-like heads and a propensity for growing “sails” on their backs. By comparing the oxygen isotope ratios of spinosaurs with other reptiles buried in the same strata, some researchers have suggested that spinosaurs primarily ate fish and may have been semiaquatic in their mode of life. The largest known spinosaur, Spinosaurus aegyptiacus, with its curiously abbreviated hindlimbs and very dense bones, was perhaps best suited for a semiaquatic lifestyle. The remains of a fish, an Iguanodon, and a pterosaur have been found in the abdominal regions of spinosaurs. It is unknown whether or not these were common prey items of spinosaurs or simply items of opportunity snagged out of necessity during the Flood. As with other dinosaurs, the remains of spinosaurs are presently only known from Flood strata. Spinosaur fossils have been found in upper Jurassic and Cretaceous sedimentary rock layers that may have been deposited fairly late in the inundatory phase of the Flood sequence. Thus far, remains assigned to the Spinosauridae are known from Europe, Africa, Asia, and Australia. Fossils from the Americas are dubiously assigned to the family, and thus far no material has been discovered in Antarctica. These apparent exceptions are perhaps indicative of insufficient sampling rather than a genuine absence. Spinosaurs were among the largest of theropod dinosaurs. Adults ranged in length between 25 feet (8 m) and 50 feet (15 m) and apparently weighed between 2,200 pounds (1,000 kg) and 22,000 pounds (10,000 kg)! Not all spinosaurs had “sails” on their backs, but it appears that most did. The sails were framed by elongated spinous processes of the vertebrae and covered in skin. In Spinosaurus, these sails stretched over 6 feet (2 m) high! Some researchers have suggested that these structures supported sizable fat deposits. Others think that the “sails” acted as body-temperature regulators or functioned primarily as display organs. Whatever their function was—or functions were—vertebral “sails” of this sort were somewhat unusual; and they are certainly fascinating. Another common feature of spinosaurs was a very narrow, elongated, crocodile-like head. Spinosaur teeth were also unusual. Most theropod teeth were blade-like, backward-curving, and serrated like steak knives. Spinosaur teeth, on the other hand, were cone-shaped with little or no curve; and they often lacked serrations sporting fine, lengthwise furrows instead. The front teeth of spinosaurs were individually socketed and spaced apart, while the back teeth in some varieties were in a more conventional arrangement. This may suggest that at least the front teeth were constantly exposed, like in crocodiles. The nostrils of spinosaurs were also placed farther back on their heads (closer to their eyes) than most theropods—an arrangement most often seen in aquatic animals, like ichthyosaurs, mosasaurs, and whales. Lastly, the first claw of each forelimb was unusually large (hence the meaning of Baryonyx’s name: “heavy claw”). Taken together, these features and others both unify spinosaurs as a group and distinguish them from other theropod dinosaurs. They were a magnificent demonstration of God’s creativity!
Why is Social and Emotional Learning So Important in PreK-12 Education? Published September 26, 2017 Nurturing students’ emotional development offers significant benefits in and outside the classroom. With so much focus on ensuring students learn subject-area skills such as math and science, are students’ social and emotional needs also being met in today’s elementary and secondary classrooms? A growing body of research identifies successful social and emotional learning (SEL) as a key element for advancing student achievement in school and beyond. This emerging learning practice is being integrated in classrooms and schools, as well as in the home to help students learn how to manage emotions, set positive goals, feel empathy toward others and engage in positive relationships. Our School team's Inspired Ideas blog features guest posts and insights from preK-12 educators about teaching social and emotional learning skills in today's classrooms. Learn more about the positive effects of SEL by taking the short quiz below. All school districts strive to create a learning environment where all students can reach their full potential. Increasingly, achieving this takes more than subject area instruction alone. The recently updated Every Student Succeeds Act (ESSA) also includes specific guidelines designed to give school districts the tools to support student development by gaining competencies through social and emotional learning (SEL). Teaching SEL skills can help increase students’ self-awareness and impulse control, boost attendance rates and help them make constructive and responsible decisions in and outside of the classroom. When combined with effective academic instruction, SEL can help all students have a positive and well-rounded educational experience. Explore these other resources to learn more about the research, practices, and benefits of social emotional learning in preK-12 education today: - Edutopia: Social Emotional Learning - We Are Teachers: Social Emotional Learning Resources - Social Emotional Learning on The American Institute for Research - The Wallace Foundation To help all schools create a culture of empathy and kindness, McGraw-Hill is proud to team up with Kids for Peace in support of the Great Kindness Challenge. Join the thousands of schools and more than 10 million students taking part in the next Challenge from January 22-26, 2018!
Diastolic Blood Pressure Diastolic blood pressure measures the pressure in your blood vessels between heartbeats (when your heart is resting). Represented by the bottom number in a blood pressure reading, diastolic blood pressure is considered low when the blood pressure reading is below 60; a diastolic blood pressure reading higher than 90 is considered high. Lifestyle changes, such as losing weight, can help lower diastolic blood pressure. Blood pressure is the amount of force (pressure) that blood exerts on the walls of the blood vessels as it passes through them. There are two pressures measured for blood pressure: - Pressure while the heart is beating (known as systolic blood pressure) - Pressure while it is relaxed (known as diastolic blood pressure). Diastolic blood pressure measures the pressure in your blood vessels between heartbeats, when your heart is resting. When measuring diastolic blood pressure, a cuff of fabric is wrapped around the arm and then slightly inflated. The blood pressure shows up on a gauge attached to the cuff. The healthcare provider reads the numbers from the gauge as air is released from the cuff. This device that reads blood pressure is called a sphygmomanometer. Blood pressure can also be measured with a blood pressure machine. The two numbers that measure your blood pressure are written like a fraction: one number on top and one on the bottom. For example, what many people consider normal blood pressure is read as 120/80. The number on top is the systolic pressure. It measures the pressure inside your blood vessels at the moment your heart beats. The number on the bottom is your diastolic blood pressure. It measures the pressure when your heart is between beats. Diastolic blood pressure changes frequently throughout the day. Things that can make diastolic blood pressure change within a few minutes include: - Level of exercise - Amount of tension - Nicotine use. Therefore, it's best to use several blood pressure readings to arrive at your average blood pressure. Be sure to look at your overall health, lifestyle, diet, and family history when comparing your blood pressure to what's considered "normal blood pressure." These factors may cause you to have a higher or lower blood pressure than what's considered normal.
In 1849 floods swept through the Great Glen in the Highlands of Scotland, breaching the Caledonian Canal and destroying the stone bridge over the River Oich. James Dredge a brewer turned engineer from Bath in Somerset, England, designed this new iron bridge using his patented 'taper principle'. The river crossing needed a single wide span to avoid the dangers of more floods so a stone bridge was out of the question. Dredge's sophisticated design differs from a normal suspension bridge in two ways; it is lighter since the chains get gradually thinner towards the centre and it is more stable in that if you break the bridge in the middle it will stay up, in theory at least. Roads came late to the Highlands where goods were traditionally transported by pack animals over poor tracks. By the 1830s the building of roads and the Caladonian Canal by Thomas Telford had transformed communications in the area. There was now a stage coach service along this road three times a week. The bridge would have been used by local traffic, by wool and horse traders, as well as the first tourists and the huge cattle droves heading south every autumn. Larger cargoes, and ships avoiding the journey round the north of Scotland, would have used the Canal. In 1932 the bridge fell into disuse as the increase in traffic required larger bridges.
A shocking 12.7 million tonnes of plastic is estimated to end up in our oceans every year. Everything from plastic bottles and bags to microbeads clogging the marine ecosystems and contaminating the wild animals who live in them. Travelling on ocean currents this plastic is now turning up in every corner of our planet, from British beaches to uninhabited Pacific Islands. It is even being found trapped in Arctic ice. Our oceans are slowly turning into a soup of plastic and the effects on ocean life are devastating. Big pieces of plastic are choking turtles and entangling seabirds. Microbeads are clogging the stomachs of creatures who mistake it for food, from tiny plankton to whales. Plastic is entering every level of the ocean food chain - and if you eat seafood - in your stomach! Why is plastic bad for the oceans? Over 80% of the plastic in our oceans comes from land-based sources. Ocean-based sources, such as overboard discharges from ships and discarded fishing gear, account for the other 20%. Food and drink containers and packaging are the largest component of solid waste. These items, together with plastic bags, represent the largest component of marine plastic waste. Packaging and single-use disposable products are not only killing ocean life they represent an unsustainable use of precious resources - such as oil, trees, and water. In the ocean, disagreed plastic injures and kills fish, seabirds and marine mammals. Marine plastic pollution has impacted hundreds of species worldwide, including 86% of all sea turtle species, 44% of all seabird species and 43% of all marine mammal species. Most fatalities are a direct result of ingestion, a slow and painful death from starvation, suffocation, infection, or drowning. Seabirds that feed on the ocean surface are especially prone to ingesting plastic that floats. Adults feed these items to their chicks resulting in detrimental effects on chick growth and survival. This was highlighted by the effect on Albatross chicks by Sir David Attenborough in the groundbreaking Blue Planet 2 series broadcast in 2017. Floating plastics in the oceans have been found to accumulate pollutants and transport them via ocean currents, providing transport to invasive marine species. Increasingly, research shows that marine life that ingests plastics coated with pollutants can absorb these pollutants their bodies. Those same pollutants are now being found in the human food chain. As the amount of disposable packaging and products continues to increase, controlling litter through public education and cleanup of streets and waterways requires significant and sustained funding for education. Our current wastage of plastic products in unsustainable, particularly, single-use, so-called disposable items such as straws, hot drink cups, bottles and can holders. Save Me believe education is key to solving this problem. We have to stop the volume of plastic waste currently entering our oceans and that is best achieved by making people aware of the impact of their everyday waste. We have to stop making the problem worse whilst we try to clean up the waste we have already polluted our oceans and marine life with. How much plastic is there in the ocean? Greenpeace state a whopping 12.7 Million tonnes of plastic is estimated to end up in our oceans every year. Most of our waste consists of everyday items such as bottles, wrappers, straws, and bags. Yet the vast majority of debris found floating far offshore is much smaller. Tiny fragments, broken-down by the ocean movement and rocks, smaller than your fingernail, are called microplastic. It is widely understood that the largest concentrations of floating microplastics occur in subtropical ocean currents, called gyres, where surface currents converge in an oceanographic “dead-end.” These so-called “garbage patches” of microplastics are well-documented with data in the North Atlantic and North Pacific oceans. However, very few surveys have ever been carried out in the Southern Hemisphere oceans and outside of the subtropical gyres. Small differences in the oceanographic models give vastly different estimates of microplastic abundance in these regions. Floating micro plastics collected in plankton nets are the best-quantified type of plastic debris in the ocean, in part because they were initially noted by researchers collecting and studying plankton decades ago. Yet micro plastics represent a small part of the total amount of plastic now in the ocean. “Plastic” is a generic term for a variety of synthetic polymers with variable material properties, including density. This means some common consumer plastics, such as PET (Polyethylene Terephthalate,) mainly used for clear plastic drink bottles, is denser than seawater and will sink upon entering the ocean. Measuring plastics on the seafloor is a huge challenge in shallow waters close to shore, no one yet knows how to measure across vast ocean basins where water depth is measured in KM’s. We do know that these larger pieces of plastics will eventually become microparticles. Still, the time it takes for large objects, including consumer products, buoys and fishing gear, for example, to fragment to millimetre-sized pieces upon exposure to sunlight, remains unknown. Just how small those pieces become before (or if) they are degraded by marine microorganisms is even less certain, in large part because of the difficulty in collecting and identifying microscopic particles as plastics. If we know that a massive amount of plastic is entering the ocean each year, what does it matter if it is a bottle cap on a beach, a lost lobster pot on the seafloor, or a nearly invisible particle floating thousands of miles offshore? If plastic waste were simply an aesthetic problem, perhaps it wouldn’t, but ocean plastics pose a threat to a wide variety of marine animals, so their risk is determined by the amount of plastic waste an animal encounters, as well as the size and shape of that waste. To a curious seal, an intact packing strap (used to protect a box in transit) drifting in the water is a serious entanglement hazard. How many bits of floating micro plastic might be ingested by large filter-feeding whales who feed on microscopic plankton? Until we know where the millions of tons of plastics reside in the ocean, we can’t fully understand the full impact on the marine ecosystem. What animals and birds are affected by Ocean plastics Article originally published by National Geographic Like many other marine animals, sea turtles mistake plastic waste for a viable food source, sometimes causing blockages in their digestive system. Although the declining sea turtle populations in the oceans are due to a variety of factors, most of which involve human exploitation, plastic pollution plays a significant role. Separate studies from 2013 suggest as many as 50 percent of sea turtles are ingesting plastic at an unprecedented rate and dying because of it. Another study of Loggerhead Turtles found that 15 percent of young turtles examined had ingested such enormous quantities of plastic that their digestive system was obstructed. Seals and Sea Lions Marine life can become entangled in a variety of ocean debris including fishing nets, lines, and lures. Still, there are a number of seals and sea lions that become entangled in plastic bags or plastic packing straps leading to injury and death. In fact, plastic packing straps continue to impact the Steller Sea Lion population. An eight-year study in south-east Alaska and British Columbia documented 388 Sea lions entangled in plastic debris. These plastic packing straps can become so embedded in the animal that it can lead to severe infection and death. Plastic pollution leads to the death of millions of marine bird species each year. The Albatross has been deeply impacted by plastic debris due to they're hunting technique. Albatross skim the surface of the ocean with their beaks to catch fish or squid but are now picking up plastic debris as well. Shockingly, an estimated 98 percent of Albatross studied were found to have ingested some kind of plastic debris. Once the plastic has been ingested, it causes an obstruction in the digestive tract that can puncture internal organs, leading to a slow and painful death. Fish, along with pretty much any marine mammal that brings in water through its gills, are increasingly at risk to microscopic plastic debris. A study performed at the University of Exeter suggests that by breathing microscopic marine debris through its gills a fish or marine mammal could take up to six times as long to clear the debris than if it had ingested it orally. A number of studies suggest that the fish and seafood we consume have ingested plastic microbeads. Humans, at the top of the food chain, are at risk from biomagnification of plastic from our food. Whales and Dolphins Like other marine mammals, whales often mistake marine debris for a potential food source. A whales mouth is so large it unknowingly picks up plastic debris (a technique observed in baleen whales). Necropsies performed after numerous whale stranding’s saw an increase in the amount of plastic debris found. A study also found that hundreds of species of cetaceans have been negatively impacted by plastic pollution in the past two decades. The ingested plastic often puncturing and tearing the stomach lining, leading to starvation and death. According to Marine Pollution Bulletin, cetaceans are ingesting plastic debris at a rate as high as 31 percent, and in turn, 22 percent of those cetaceans were at an increased risk of death. Why is plastic harmful to ocean animals? A new study sheds light on why so many seabirds, fish, whales, and other critters are gobbling up so much marine plastic debris. And it's not quite what scientists thought. As the oceans fill with plastic debris, hundreds of marine species eat astonishing amounts of it. Yet the question of why so many species, mistake so much of it for food has never been fully explored. Now a new study explains why: It smells like food. Algae are consumed by Krill, a small crustacean that is the primary food source for many seabirds. As algae break down naturally in the ocean, they emit a stinky sulphur odour known as dimethyl sulphide (DMS). Seabirds in the hunt for Krill have learned that the sulphur odour will lead them to the feeding grounds. It turns out that floating plastic debris provides the perfect platform on which algae thrive. As the algae break down, emitting the DMS odour, seabirds, following their noses in search of Krill, are led into an “olfactory trap,” according to a new study published November 9 in Science Advances. Instead of feeding on Krill, they feed on plastic. How can we keep Plastic out of our oceans? Plastic waste is a global problem. It has been accumulating rapidly in the world’s oceans, roughly doubling every decade. In 2014, a global analysis measured ocean plastic at a quarter of a billion metric tons, much of it suspended in small rice-sized particles. More than 200 animal species have been documented consuming plastic, including turtles, whales, seal, birds, and fish. Seabirds are especially at risk; a study published last year by scientists in Australia concluded that virtually all seabirds have consumed plastic. Scientists have long known that ocean plastic is consumed because it looks like food. Sea turtles, for example, often mistake flimsy, clear plastic bags for jellyfish. Other marine animals, including fish, gobble bits of rice-sized micro plastics broken down by sunlight and wave action because they resemble the small particles they normally ea Now scientists have discovered that DMS (dimethyl sulphide) as a strong predictor of plastic consumption and the “keystone info chemical” that drew marine animals to plastic as if it were Krill. Odour extraction tests confirmed that three common varieties of plastic acquired a “DMS signature” after less than a month in the Ocean. Scientists have also confirmed that the birds most attracted to the DMS odour are the Albatross, Petrels, and Shearwaters three species that are most severely affected by plastic consumption. All three species nest in underground burrows, and juvenile birds spend many more months on the ground than birds that nest above the surface. Consequently, burrow-nesting birds rely much more heavily on their sense of smell to get around. Could plastic lead to the extinction of marine species While we might understand that plastic pollution in the world’s oceans is not a good thing, we are only just beginning to realise the impact that plastics have on marine ecosystems. There are an estimated 270,000 tons of plastic floating on the surface of the ocean and according to a recent study authored by researchers at Plymouth University, a staggering 700 different marine species are threatened by its presence. More than this, researchers believe that plastic plays a role in rising rates of species extinction. Research found that 693 species had been documented as having encountered plastic debris, with nearly 400 involving entanglement and ingestion. Between entanglement, ingestion and ecosystem damage, the threat of plastic pollution impacts marine species both large and small. We have seen around 52 percent of the world’s wildlife disappear in the past 40 years, and if we continue to dump plastic into the world’s oceans, this number is set to increase exponentially. How can you reduce your consumption of plastic products? The good news is that we can ALL do something. First, we need to accept that Humans are to blame for plastic pollution. However, this also means we have the power to stop this marine destruction. So, if you want to stand up for the world’s marine animals, the best place to start is with your personal plastic consumption. Here are 9 top tips from Greenpeace: 1.Carry a reusable bottle In the UK we use over 35 million plastic bottles every year! Carrying a reusable bottle is a great way to cut your plastic use and save money too! There’s even an app that tells you where you can refill your bottle for free! 2. Say no to plastic straws Plastic straws are bad news for our oceans. Next time you order a drink, think about whether you need a straw, and if you don’t, just say no! You can also ask your local pub to stop adding straws to drinks as standard and offer paper straws to those who want one. 3.Take a reusable coffee cup 2.5 Billion coffee cups are thrown away every year in the UK – and less than 1 in 400 are recycled. Carry a reusable cup with you – some cafes even offer a small discount if you use your own cup (and if they don’t ask them why not)! 4. Avoid excessive food packaging Whether it’s making different choices in the supermarket or choosing a different place to shop, we can all try and cut down the plastic we buy. And as an added bonus, loose fruit and veg is often cheaper than pre-packaged alternatives! 5. Use refill stations for detergent There are some products where it’s difficult to avoid a plastic container (for example washing up liquid or laundry liquid) – the good news is that there are an increasing amount of places where you can refill your old bottles. 6. Say no to disposable cutlery We’ve all been there – caught out in a cafe or at a train station when we’ve bought a salad or a yogurt but the only cutlery on offer is plastic! Whilst it’s hard to plan for every opportunity, consider carrying a spoon or fork in your bag or keeping cutlery in your desk at work. 7. Get your milk delivered Although the early morning sound of a milk float is not as common as it used to be, there are still lots of places in the UK where you can get milk delivered in glass bottles – which are then collected and reused. 8. Avoid microbeads The good news is that the UK government have announced a ban on microbeads! However until the ban comes into force in 2018, there will still be products on the shelves, so keep checking those labels before you buy and avoid products containing polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE) and nylon. 9. Carry a shopping bag Since the plastic bag charge was introduced in England, there’s been a massive 85% drop in their use. Many of us are used to carrying an extra bag with us – if you still find it hard to remember, try a foldaway one that you can carry in your normal day bag. Just by making a few small changes can have a big impact on the amount of plastic we use on a day-to-day basis.
The students at Foster got to learn how we can make our own soil! The earth does this everyday naturally, but humans can actively make soil too! This process is called composting. For a healthy compost pile we need a balance of green materials (fresh kitchen or yard scraps, still moist) and brown materials (dead materials like dried leaves, tree mulch, newspaper or cardboard), air, water and the decomposers that live inside. We learned that earthworms are one of the major invertebrate decomposers that help to break down all organic matter and poop it out as very nutritious fertilizer for plants. Worm poop is called castings and farmers buy bags of their poop to add to their gardens. Just like raising a dog or a cat, you can raise earthworms in your own home! This process called, vermiculture, is a process of composting through the process of using different types of worms (usually red wigglers, earth worms or white worms) to create a healthy mixture of organic matter and worm castings. I have my own vermiculture worm bin at my house and brought it to school so the kids could see! We took a look in the compost tumbler to see the process of decomposition of in action. Today at United Children’s Learning Academy (UCLA), the kids learned about worms and the fun and silly ways they help our gardens. We learned to wiggle down into the earth like a worm, and how to stretch and wiggle up into the air like a green bean. We triend radishes, red bell peppers, and carrots as a snack. One student said “Ms. Alexys, can I have all of the radishes?” I’d say it was a success! At Van Nuys middle school, the kids had plenty of work to do after the frost, but there were still some hearty veggies going strong! Radishes can never fail here, while the lettuces and edamame plants continue to grow. We even had time to dance- well, the parts of a plant dance that is!Our radish harvest! There were many more- this was only round 1! Our friend and volunteer, Jeff Mailes, joined us in the garden on Wednesday to introduce starting garden beds using compost mounds. A great way to provide nutrients to the soil and let the soil work while seeds grow above ground. Thank you, Jeff! One of my favorite things to show kids in the garden are all the creepy crawlies that live with our plants. Many students have not had the chance to observe or play with these helpful creatures. At Vine Elementary School, we spent an entire class digging through the soil so that we could observe earthworms. Earthworms are very helpful! They eat fruits and vegetables that have fallen and are getting rotten. Earthworm poop is full of nutrients that help our plants grow big and strong. Worms do not have any teeth or legs, so you don’t have to worry about them biting or pinching you. Ramona is full of some great gardeners and artist! We had fun creating art for our garden. While the little gardeners painted we talked about the great friends and foes of the garden. We focused on the importance of bees and how to be respectful when we see them in the garden. Many of us have been told to be scared of bees but as we talked about the importance of all pollinators in the garden many of us found that they only sting us to defend themselves. We are Great BiG GiantS in the bee world and we need to remember that the bees are more then likely scared of us. So if you see a bee in the garden make sure to be respectful and walk the other way! At South Gate Middle School, we are learning about the importance of eating healthy. The students had a great time harvesting and preparing their very own salad. It’s great to hear all the different ways they use and eat their veggies at home too! One great lesson we all learn when preparing a meal together is the lesson of community. Only working together will we be able to create something worth eating and enjoying. Thank you to the students at South Gate Middle School for working together to caring for a garden we can all eat from. Cheers!
A buck converter is a voltage step down and current step up converter. The simplest way to reduce the voltage of a DC supply is to use a linear regulator (such as a 7805), but linear regulators waste energy as they operate by dissipating excess power as heat. Buck converters, on the other hand, can be remarkably efficient (95% or higher for integrated circuits), making them useful for tasks such as converting the main voltage in a computer (12 V in a desktop, 12-24 V in a laptop) down to the 0.8-1.8 volts needed by the processor. - 1 Theory of operation - 2 Concept - 3 Efficiency factors - 4 Impedance matching - 5 See also - 6 References - 7 External links Theory of operation The basic operation of the buck converter has the current in an inductor controlled by two switches (usually a transistor and a diode). In the idealised converter, all the components are considered to be perfect. Specifically, the switch and the diode have zero voltage drop when on and zero current flow when off and the inductor has zero series resistance. Further, it is assumed that the input and output voltages do not change over the course of a cycle (this would imply the output capacitance as being infinite). The conceptual model of the buck converter is best understood in terms of the relation between current and voltage of the inductor. Beginning with the switch open (in the "off" position), the current in the circuit is 0. When the switch is first closed, the current will begin to increase, and the inductor will produce an opposing voltage across its terminals in response to the changing current. This voltage drop counteracts the voltage of the source and therefore reduces the net voltage across the load. Over time, the rate of change of current decreases, and the voltage across the inductor also then decreases, increasing the voltage at the load. During this time, the inductor is storing energy in the form of a magnetic field. If the switch is opened while the current is still changing, then there will always be a voltage drop across the inductor, so the net voltage at the load will always be less than the input voltage source. When the switch is opened again, the voltage source will be removed from the circuit, and the current will decrease. The changing current will produce a change in voltage across the inductor, now aiding the source voltage. The stored energy in the inductor's magnetic field supports current flow through the load. During this time, the inductor is discharging its stored energy into the rest of the circuit. If the switch is closed again before the inductor fully discharges, the voltage at the load will always be greater than zero. A buck converter operates in continuous mode if the current through the inductor (IL) never falls to zero during the commutation cycle. In this mode, the operating principle is described by the plots in figure 4: - When the switch pictured above is closed (on-state, top of figure 2), the voltage across the inductor is . The current through the inductor rises linearly. As the diode is reverse-biased by the voltage source V, no current flows through it; - When the switch is opened (off state, bottom of figure 2), the diode is forward biased. The voltage across the inductor is (neglecting diode drop). Current IL decreases. The energy stored in inductor L is Therefore, it can be seen that the energy stored in L increases during On-time (as IL increases) and then decreases during the Off-state. L is used to transfer energy from the input to the output of the converter. The rate of change of IL can be calculated from: With VL equal to during the On-state and to during the Off-state. Therefore, the increase in current during the On-state is given by: Conversely, the decrease in current during the Off-state is given by: If we assume that the converter operates in steady state, the energy stored in each component at the end of a commutation cycle T is equal to that at the beginning of the cycle. That means that the current IL is the same at t=0 and at t=T (see figure 4). So we can write from the above equations: The above integrations can be done graphically: In figure 4, is proportional to the area of the yellow surface, and to the area of the orange surface, as these surfaces are defined by the inductor voltage (red) curve. As these surfaces are simple rectangles, their areas can be found easily: for the yellow rectangle and for the orange one. For steady state operation, these areas must be equal. As can be seen on figure 4, and . Where D is a scalar called the duty cycle with a value between 0 and 1. This yields: From this equation, it can be seen that the output voltage of the converter varies linearly with the duty cycle for a given input voltage. As the duty cycle D is equal to the ratio between tOn and the period T, it cannot be more than 1. Therefore, . This is why this converter is referred to as step-down converter. So, for example, stepping 12 V down to 3 V (output voltage equal to one quarter of the input voltage) would require a duty cycle of 25%, in our theoretically ideal circuit. In some cases, the amount of energy required by the load is too small. In this case, the current through the inductor falls to zero during part of the period. The only difference in the principle described above is that the inductor is completely discharged at the end of the commutation cycle (see figure 5). This has, however, some effect on the previous equations. We still consider that the converter operates in steady state. Therefore, the energy in the inductor is the same at the beginning and at the end of the cycle (in the case of discontinuous mode, it is zero). This means that the average value of the inductor voltage (VL) is zero; i.e., that the area of the yellow and orange rectangles in figure 5 are the same. This yields: So the value of δ is: The output current delivered to the load () is constant, as we consider that the output capacitor is large enough to maintain a constant voltage across its terminals during a commutation cycle. This implies that the current flowing through the capacitor has a zero average value. Therefore, we have : Where is the average value of the inductor current. As can be seen in figure 5, the inductor current waveform has a triangular shape. Therefore, the average value of IL can be sorted out geometrically as follow: The inductor current is zero at the beginning and rises during ton up to ILmax. That means that ILmax is equal to: Substituting the value of ILmax in the previous equation leads to: And substituting δ by the expression given above yields: This expression can be rewritten as: It can be seen that the output voltage of a buck converter operating in discontinuous mode is much more complicated than its counterpart of the continuous mode. Furthermore, the output voltage is now a function not only of the input voltage (Vi) and the duty cycle D, but also of the inductor value (L), the commutation period (T) and the output current (Io). From discontinuous to continuous mode (and vice versa) As mentioned at the beginning of this section, the converter operates in discontinuous mode when low current is drawn by the load, and in continuous mode at higher load current levels. The limit between discontinuous and continuous modes is reached when the inductor current falls to zero exactly at the end of the commutation cycle. Using the notations of figure 5, this corresponds to : Therefore, the output current (equal to the average inductor current) at the limit between discontinuous and continuous modes is (see above): Substituting ILmax by its value: On the limit between the two modes, the output voltage obeys both the expressions given respectively in the continuous and the discontinuous sections. In particular, the former is So Iolim can be written as: Let's now introduce two more notations: - the normalized voltage, defined by . It is zero when , and 1 when ; - the normalized current, defined by . The term is equal to the maximum increase of the inductor current during a cycle; i.e., the increase of the inductor current with a duty cycle D=1. So, in steady state operation of the converter, this means that equals 0 for no output current, and 1 for the maximum current the converter can deliver. Using these notations, we have: - in continuous mode: - in discontinuous mode: the current at the limit between continuous and discontinuous mode is: Therefore, the locus of the limit between continuous and discontinuous modes is given by: These expressions have been plotted in figure 6. From this, it is obvious that in continuous mode, the output voltage does only depend on the duty cycle, whereas it is far more complex in the discontinuous mode. This is important from a control point of view. The previous study was conducted with the following assumptions: - The output capacitor has enough capacitance to supply power to the load (a simple resistance) without any noticeable variation in its voltage. - The voltage drop across the diode when forward biased is zero - No commutation losses in the switch nor in the diode These assumptions can be fairly far from reality, and the imperfections of the real components can have a detrimental effect on the operation of the converter. Output voltage ripple Output voltage ripple is the name given to the phenomenon where the output voltage rises during the On-state and falls during the Off-state. Several factors contribute to this including, but not limited to, switching frequency, output capacitance, inductor, load and any current limiting features of the control circuitry. At the most basic level the output voltage will rise and fall as a result of the output capacitor charging and discharging: During the Off-state, the current in this equation is the load current. In the On-state the current is the difference between the switch current (or source current) and the load current. The duration of time (dT) is defined by the duty cycle and by the switching frequency. For the On-state: For the Off-state: Qualitatively, as the output capacitor or switching frequency increase, the magnitude of the ripple decreases. Output voltage ripple is typically a design specification for the power supply and is selected based on several factors. Capacitor selection is normally determined based on cost, physical size and non-idealities of various capacitor types. Switching frequency selection is typically determined based on efficiency requirements, which tends to decrease at higher operating frequencies, as described below in Effects of non-ideality on the efficiency. Higher switching frequency can also reduce efficiency and possibly raise EMI concerns. Output voltage ripple is one of the disadvantages of a switching power supply, and can also be a measure of its quality. Effects of non-ideality on the efficiency A simplified analysis of the buck converter, as described above, does not account for non-idealities of the circuit components nor does it account for the required control circuitry. Power losses due to the control circuitry are usually insignificant when compared with the losses in the power devices (switches, diodes, inductors, etc.) The non-idealities of the power devices account for the bulk of the power losses in the converter. Both static and dynamic power losses occur in any switching regulator. Static power losses include (conduction) losses in the wires or PCB traces, as well as in the switches and inductor, as in any electrical circuit. Dynamic power losses occur as a result of switching, such as the charging and discharging of the switch gate, and are proportional to the switching frequency. It is useful to begin by calculating the duty cycle for a non-ideal buck converter, which is: - VSWITCH is the voltage drop on the power switch, - VSYNCHSW is the voltage drop on the synchronous switch or diode, and - VL is the voltage drop on the inductor. The voltage drops described above are all static power losses which are dependent primarily on DC current, and can therefore be easily calculated. For a diode drop, VSWITCH and VSYNCHSW may already be known, based on the properties of the selected device. - Ron is the ON-resistance of each switch, and - RDCR is the DC resistance of the inductor. The duty cycle equation is somewhat recursive. A rough analysis can be made by first calculating the values VSWITCH and VSYNCSW using the ideal duty cycle equation. For a MOSFET voltage drop, a common approximation is to use Rds(on) from the MOSFET's datasheet in Ohm's Law, V = IdsRdson(sat). This approximation is acceptable because the MOSFET is in the linear state, with a relatively constant drain-source resistance. This approximation is only valid at relatively low Vds values. For more accurate calculations, MOSFET datasheets contain graphs on the Vds and Ids relationship at multiple Vgs values. Observe Vds at the Vgs and Ids which most closely match what is expected in the buck converter. In addition, power loss occurs as a result of leakage currents. This power loss is simply - Ileakage is the leakage current of the switch, and - V is the voltage across the switch. Dynamic power losses are due to the switching behavior of the selected pass devices (MOSFETs, power transistors, IGBTs, etc.). These losses include turn-on and turn-off switching losses and switch transition losses. Switch turn-on and turn-off losses are easily lumped together as - V is the voltage across the switch while the switch is off, - trise and tfall are the switch rise and fall times, and - T is the switching period. But this doesn't take into account the parasitic capacitance of the MOSFET which makes the Miller plate. Then, the switch losses will be more like: When a MOSFET is used for the lower switch, additional losses may occur during the time between the turn-off of the high-side switch and the turn-on of the low-side switch, when the body diode of the low-side MOSFET conducts the output current. This time, known as the non-overlap time, prevents "shootthrough", a condition in which both switches are simultaneously turned on. The onset of shootthrough generates severe power loss and heat. Proper selection of non-overlap time must balance the risk of shootthrough with the increased power loss caused by conduction of the body diode. Many MOSFET based buck converters also include a diode to aid the lower MOSFET body diode with conduction during the non-overlap time. When a diode is used exclusively for the lower switch, diode forward turn-on time can reduce efficiency and lead to voltage overshoot. Power loss on the body diode is also proportional to switching frequency and is - VF is the forward voltage of the body diode, and - tno is the selected non-overlap time. Finally, power losses occur as a result of the power required to turn the switches on and off. For MOSFET switches, these losses are dominated by the gate charge, essentially the energy required to charge and discharge the capacitance of the MOSFET gate between the threshold voltage and the selected gate voltage. These switch transition losses occur primarily in the gate driver, and can be minimized by selecting MOSFETs with low gate charge, by driving the MOSFET gate to a lower voltage (at the cost of increased MOSFET conduction losses), or by operating at a lower frequency. - QG is the gate charge of the selected MOSFET, and - VGS is the peak gate-source voltage. It is essential to remember that, for N-MOSFETs, the high-side switch must be driven to a higher voltage than Vi. To achieve this, MOSFET gate drivers typically feed the MOSFET output voltage back into the gate driver. The gate driver then adds its own supply voltage to the MOSFET output voltage when driving the high-side MOSFETs to achieve a Vgs equal to the gate driver supply voltage. Because the low-side Vgs is the gate driver supply voltage, this results in very similar Vgs values for high-side and low-side MOSFETs. A complete design for a buck converter includes a tradeoff analysis of the various power losses. Designers balance these losses according to the expected uses of the finished design. A converter expected to have a low switching frequency does not require switches with low gate transition losses; a converter operating at a high duty cycle requires a low-side switch with low conduction losses. A synchronous buck converter is a modified version of the basic buck converter circuit topology in which the diode, D, is replaced by a second switch, S2. This modification is a tradeoff between increased cost and improved efficiency. In a standard buck converter, the flyback diode turns on, on its own, shortly after the switch turns off, as a result of the rising voltage across the diode. This voltage drop across the diode results in a power loss which is equal to - VD is the voltage drop across the diode at the load current Io, - D is the duty cycle, and - Io is the load current. By replacing diode D with switch S2, which is advantageously selected for low losses, the converter efficiency can be improved. For example, a MOSFET with very low RDSON might be selected for S2, providing power loss on switch 2 which is In both cases, power loss is strongly dependent on the duty cycle, D. Power loss on the freewheeling diode or lower switch will be proportional to its on-time. Therefore, systems designed for low duty cycle operation will suffer from higher losses in the freewheeling diode or lower switch, and for such systems it is advantageous to consider a synchronous buck converter design. Without actual numbers the reader will find the usefulness of this substitution to be unclear. Consider a computer power supply, where the input is 5 V, the output is 3.3 V, and the load current is 10A. In this case, the duty cycle will be 66% and the diode would be on for 34% of the time. A typical diode with forward voltage of 0.7 V would suffer a power loss of 2.38 W. A well-selected MOSFET with RDSON of 0.015 Ω, however, would waste only 0.51 W in conduction loss. This translates to improved efficiency and reduced heat loss. Another advantage of the synchronous converter is that it is bi-directional, which lends itself to applications requiring regenerative braking. When power is transferred in the "reverse" direction, it acts much like a boost converter. The advantages of the synchronous buck converter do not come without cost. First, the lower switch typically costs more than the freewheeling diode. Second, the complexity of the converter is vastly increased due to the need for a complementary-output switch driver. Such a driver must prevent both switches from being turned on at the same time, a fault known as "shootthrough". The simplest technique for avoiding shootthrough is a time delay between the turn-off of S1 to the turn-on of S2, and vice versa. However, setting this time delay long enough to ensure that S1 and S2 are never both on will itself result in excess power loss. An improved technique for preventing this condition is known as adaptive "non-overlap" protection, in which the voltage at the switch node (the point where S1, S2 and L are joined) is sensed to determine its state. When the switch node voltage passes a preset threshold, the time delay is started. The driver can thus adjust to many types of switches without the excessive power loss this flexibility would cause with a fixed non-overlap time. The multiphase buck converter is a circuit topology where basic buck converter circuits are placed in parallel between the input and load. Each of the n "phases" is turned on at equally spaced intervals over the switching period. This circuit is typically used with the synchronous buck topology, described above. This type of converter can respond to load changes as quickly as if it switched n times faster, without the increase in switching losses that would cause. Thus, it can respond to rapidly changing loads, such as modern microprocessors. There is also a significant decrease in switching ripple. Not only is there the decrease due to the increased effective frequency, but any time that n times the duty cycle is an integer, the switching ripple goes to 0; the rate at which the inductor current is increasing in the phases which are switched on exactly matches the rate at which it is decreasing in the phases which are switched off. Another advantage is that the load current is split among the n phases of the multiphase converter. This load splitting allows the heat losses on each of the switches to be spread across a larger area. This circuit topology is used in computer power supplies to convert the 12 VDC power supply to a lower voltage (around 1 V), suitable for the CPU. Modern CPU power requirements can exceed 200W, can change very rapidly, and have very tight ripple requirements, less than 10mV. Typical motherboard power supplies use 3 or 4 phases, although control IC manufacturers allow as many as 6 phases One major challenge inherent in the multiphase converter is ensuring the load current is balanced evenly across the n phases. This current balancing can be performed in a number of ways. Current can be measured "losslessly" by sensing the voltage across the inductor or the lower switch (when it is turned on). This technique is considered lossless because it relies on resistive losses inherent in the buck converter topology. Another technique is to insert a small resistor in the circuit and measure the voltage across it. This approach is more accurate and adjustable, but incurs several costs—space, efficiency and money. Finally, the current can be measured at the input. Voltage can be measured losslessly, across the upper switch, or using a power resistor, to approximate the current being drawn. This approach is technically more challenging, since switching noise cannot be easily filtered out. However, it is less expensive than emplacing a sense resistor for each phase. Conduction losses that depend on load: - Resistance when the transistor or MOSFET switch is conducting. - Diode forward voltage drop (usually 0.7 V or 0.4 V for schottky diode) - Inductor winding resistance - Capacitor equivalent series resistance - Voltage-Ampere overlap loss - FrequencyswitchCV2 loss - Reverse latence loss - Losses due driving MOSFET gate and controller consumption. - Transistor leakage current losses, and controller standby consumption. By the equation for electric power: - Vo is the output voltage - Io is the output current - η is the power efficiency (ranging from 0 to 1) - Vi is the input voltage - Ii is the input current By Ohm's Law: - Zo is the output impedance - Zi is the input impedance Substituting these expressions for Io and Ii into the power equation yields: As was previously shown for the continuous mode, (where IL > 0): - D is the duty cycle Substituting this equation for Vo into the previous equation, yields: which reduces to: This shows that it is possible to adjust the impedance ratio by adjusting the duty cycle. This is particularly useful in applications where the impedance(s) are dynamically changing. - Boost converter - Buck-boost converter - Split-Pi (Boost-Buck Converter) - General DC-DC converters and Switched-mode power supplies \|This article needs additional citations for verification. (January 2009)\| - "Power MOSFET datasheet list". http://www.magnachip.com. MagnaChip. Retrieved 25 January 2015. - Jim Williams (1 January 2009). "Diode Turn-On Time Induced Failures in Switching Regulators". - "NCP5911 datasheet". http://www.onsemi.com. ON Semiconductor. Retrieved 25 January 2015. - Guy Séguier, Électronique de puissance, 7th edition, Dunod, Paris 1999 (in French) - Tom's Hardware: "Idle/Peak Power Consumption Analysis" - NCP5316 4-5-6-phase converter datasheet - "iitb.ac.in - Buck converter". 090424 ee.iitb.ac.in \|Wikimedia Commons has media related to Buck converters.\| - P. Julián, A. Oliva, P. Mandolesi, and H. Chiacchiarini, “Output discrete feedback control of a DC-DC Buck converter,” in Proceedings of the IEEE International Symposium on Industrial Electronics (ISIE’97), Guimaraes, Portugal, 7-11Julio 1997, pp. 925–930. - H. Chiacchiarini, P. Mandolesi, A. Oliva, and P. Julián, “Nonlinear analog controller for a buck converter: Theory and experimental results”, Proceedings of the IEEE International Symposium on Industrial Electronics (ISIE’99), Bled, Slovenia, 12–16 July 1999, pp. 601–606. - M. B. D’Amico, A. Oliva, E. E. Paolini y N. Guerin, “Bifurcation control of a buck converter in discontinuous conduction mode”, Proceedings of the 1st IFAC Conference on Analysis and Control of Chaotic Systems (CHAOS’06), pp. 399–404, Reims (Francia), 28 al 30 de junio de 2006. - Oliva, A.R., H. Chiacchiarini y G. Bortolotto “Developing of a state feedback controller for the synchronous buck converter”, Latin American Applied Research, Volumen 35, Nro 2, Abril 2005, pp. 83–88. ISSN: 0327-0793. - D’Amico, M. B., Guerin, N., Oliva, A.R., Paolini, E.E. Dinámica de un convertidor buck con controlador PI digital. Revista Iberoamericana de automática e informática industrial (RIAI), Vol 4, No 3, julio 2007, pp. 126–131. ISSN: 1697-7912. - Chierchie, F. Paolini, E.E. Discrete-time modeling and control of a synchronous buck converter .Argentine School of Micro-Nanoelectronics, Technology and Applications, 2009. EAMTA 2009.1–2 October 2009, pp. 5 – 10 . ISBN 978-1-4244-4835-7 . - Interactive Power Electronics Seminar (iPES) Many Java applets demonstrating the operation of converters - Model based control of digital buck converter Description and working VisSim source code diagram for low cost digital control of DC-DC buck converters - SPICE simulation of the buck converter - Tutorial video explaining buck converters with example buck converter circuit design - Switch-Mode Power Supply Tutorial - Detailed article on DC-DC converters which gives a more formal and detailed analysis of the Buck including the effects of non-ideal switching (but, note that the diagram of the buck-boost converter fails to account for the inversion of the polarity of the voltage between input and output). - DC-DC Power Converter Case study - On the Power Efficiency Optimization
Status of Whitebark Pine in Crater Lake National Park, Oregon, 2000 Whitebark pine is a long-lived and hardy tree able to thrive at sites which experience harsh climatic forces. The pine’s large and nutritious seeds are prized by Park wildlife including Clark’s nutcrackers, black bears, and red squirrels. Elk and grouse use trees for shelter. Their canopies support arboreal lichens and understory flora such as woodrush and currants. Whitebark pine also stabilize soil and regulate snowmelt. Although blister rust occurs on all five-needled pines, such as western white (Pinus monticola) and sugar (P. lambertiana), whitebark pine is by far the most susceptible. Spores of the fungus arrive in moisture-laden air and infect five-needled pines and currant bushes. It is not fatal to currants, but once the spores reach the needles of whitebark pine, the infection spreads to branches. Within a year or two, a canker is formed by the fruiting bodies thus destroying the tree’s living tissue in the vicinity of the infection. If the infection is at or near the main stem of the tree, topkill will occur, seriously threatening the tree’s ability to survive. Often, other damaging agents such as mountain pine beetle (Dendroctonus rufipenis), wind, and alternate fungi take advantage of the injured tree and contribute to its death. White pine blister rust has proven very lethal in other parts of North America where up to 90 percent mortality has been estimated (Kendall 1994).
This month, EDSITEment goes back to school; celebrates the Statue of Liberty; marks the 150th anniversary of the Emancipation Proclamation; discusses “Bartleby, the Scrivener” (even if you would prefer not to); and looks back at August 1968. Back-to-School Fall 2012 We’ve culled our most popular lessons in history, literature, art, and culture and foreign languages to jump start your class: - U.S. History and Government - Literature & Language Arts - World History & Culture - Folktales, Fairytales, and Mythology - Art History - World Languages The Statue of Liberty In August 1884, on the shore of New York Harbor, the cornerstone was laid for what is today one of the most recognized monuments in the United States: the Statue of Liberty. The statue’s location, overlooking Ellis Island, meant that in the years to come the “Mother of Exiles” would be one of the first things millions of immigrants would see when entering the United States. In August of 1894, ten years after the monument’s cornerstone was set in place, Congress created the Bureau of Immigration to oversee the thousands of newcomers who were greeted by the statue every year. Learn more about the Statue of Liberty as well as find information on your ancestry, immigrants today, suggested related activities, and featured lessons and websites. NEH’s Emancipation Nation To mark the 150th anniversary of the Emancipation Proclamation, NEH is hosting a series of events on National Constitution Day, September 17, 2012. NEH has collaborated with University of Richmond President and Civil War historian Edward L. Ayers to create a number of opportunities—including an interactive discussion with leading emancipation historians and a creative student contest—that encourage high school and college students across the nation to consider the immediate and long-term implications of emancipation as it relates to the U.S. Constitution and their lives today. NEH has partnered with the Smithsonian’s National Museum of American History to live stream the interactive discussion taking place at the Smithsonian’s Warner Bros. Theater. The online resource portal contains relevant essays, EDSITEment lesson plans, an interactive timeline with links to NEH-funded films and interactive websites, and instructions for teachers and community members on how to host watch parties for the live streamed event. Through this site, teachers and students may also interact with one another and the presenters. Herman Melville’s Tale of Wall Street: “Bartleby the Scrivener” One of the most powerful of stories ever written about our attitudes to our neighbors and fellow citizens. This Launchpad provides background materials and discussion questions to enhance your reading and understanding of Herman Melville’s short story “Bartleby, the Scrivener.” To help readers understand the story and its wider significance, there are a series of questions for reflection. After discussing or thinking about these questions, click on the videos to hear editors Amy A. Kass, Leon R. Kass, and Diana Schaub converse with guest host Wilfred McClay about the story. August 1968: Miami and Siege of Chicago The 1968 Exhibit is an ambitious, state-of-the-art, multimedia exhibit that looks at how the experiences of the year fueled a persistent, if often contradictory, sense of identity for the people who were there. It is the unsettled nature of the debate about damage done or victories won that makes an exhibit on this subject so compelling and urgent. In August, Richard Nixon is nominated at the Republican National Convention in Miami and Hubert Humphrey is nominated at the Democratic Convention in Chicago while rioting breaks out in the streets.
Description of Historic Place Rideau Canal National Historic Site of Canada is a 200 km man-made waterway running through a corridor of communities from Ottawa River to Lake Ontario. It was built in the mid 19th century. The designation includes lands alongside the canal which are administered by Parks Canada. Rideau Canal was designated a national historic site of Canada because of the significance of: - the construction of the canal system, - the survival of a high number of original canal structures including locks, blockhouses, dams, weirs and original lockmasters’ houses plus the integrity of most lockstations, - the unique historical environment of the canal system. The heritage value of the Rideau Canal lies in the health and wholeness of its cultural landscape, as a witness of the early 19th-century forms, materials and technologies of the waterway, and as a dynamic reflection of the longstanding human and ecological inter-relationships between the canal and its corridor. The Rideau Canal was built for the British government by Lieutenant-Colonel John By as a defensive work in 1826-1837. Canada assumed responsibility for its management in 1855, and the waterway served as a commercial transportation route through most of the 19th and 20th centuries. Parks Canada acquired the canal to sustain its recreational operation in 1972. Sources: HSMBC Minutes, June 1924, 1967, November 1987; Commemorative Integrity Statement, 1987. Aspects of this site which contribute to its heritage values include: - the completeness of the cultural landscape as a longstanding system of transportation facilities including the waterway, locks, blockhouses, dams, weirs and lockstations with lockmasters’ houses, associated shore lands and communities, extensive wetlands and lakes, - the canal bed and its subdivision into lockstations, - the original built resources, in particular, the form, craftsmanship, materials and locations of its early blockhouses, lockmasters’ houses, and lockstation buildings canal walls, locks, dams and weirs, - defensive siting, materials and functional design of blockhouses, lockmasters’ houses and lockstation landscapes, and remnants such as the guardhouses at Jones Falls and Morton’s Dam, - archaeological remnants of construction including the ruin of the engineers’ building, the remains of the lime kilns, the Sapper’s Bridge and blacksmith shop at the Ottawa Locks, the construction camp at Newboro, - remnants of engineering design including the canal route, walls, locks, weirs, bridges such as the remains of Ottawa’s Sapper’s Bridge and submerged bridge at the Jones’ Falls dam, and dams (especially the stone arch dams at Long Island and Jones Falls, and the underwater site of the original dam at Merrickville), and the operational technologies including the manual operation of all locks except Newboro, Black Rapids and Smiths Falls Combined Locks, - the wetlands and lakes created by the canal construction, - on-going operation of the canal and all evidence of its continuous seasonal operation since 1832 (particularly the integral role of its engineering works in the sustained operation of the navigation system as witnessed by facilities at all locks except Locks 29, 30 & 31 at Smiths Falls Combined, the surviving historic layout and configuration of lockstations including their patterns of open space and circulation), - the continuity of historic, ecological and visual associations with shore lands and communities along the route, particularly pathways, view sheds from the canal locks and channel to the central core of Ottawa between the Mackenzie King Bridge and the Ottawa River, view sheds between the canal, the fortifications, the harbour in the landscape of Kingston harbour, views from the canal shore lands and communities between Becketts Landing and Kilmarnock lockstation, along Newboro channel, at Chaffeys Locks, and at the lockstations at Davis Locks, Jones Falls, Upper and Lower Brewers and Kingston Mills.
01949 851 441 07961 913 735 Have you put up your tree yet? Ever wondered what happens to our trees during these harsh Winter months? Read Ollie’s piece to find out. “When we look out at our gardens and the British landscape at this time of year there isn’t much greenery about. We are all familiar with the scenes of winter with frosted grass and the silhouettes of naked trees against the low sun, but have you ever stopped to think about what is going on inside those bare trees and why? The harsh winter months consist of shortened days with minimal light levels, freezing temperatures and strong winds, which the trees around us have to endure. Over millennia deciduous trees have become perfectly adapted to survive these testing months, by shutting down and becoming dormant. Deciduous trees prepare themselves for dormancy during autumn as the day length steadily reduces and there is less and less light for photosynthesis. The reduction in light levels triggers trees to begin the process of shedding their leaves. Trees withdraw sugars from their leaves and store them within the tissues of branches, trunks and roots. As chlorophyll (the pigment that makes leaves green) is broken down, other pigments in the leaves become apparent and zing out in vibrant shades of yellow and red, before the leaves detach from the twigs and fall. Another advantage of losing leaves during winter is to reduce the effects of strong winds. Leaves can act like a sail, so having bare stems allows the wind to pass through the crown easily, which in turn reduces the pressures on roots anchoring trees in the ground. As average temperatures fall, cellular activity in the parts of the tree above ground grinds to a halt. Below ground, roots never become fully dormant; as long as the ground doesn’t freeze, they continue to grow, albeit at a greatly reduced rate. If the ground does freeze, roots close to the surface cease to grow until the temperature rises and they become active again. Most mature trees have a thick layer of tough bark, which provides a defence against pests and diseases and acts as an excellent insulating layer to protect the wood beneath. The increased sugar levels in the tissues of the wood also act as an anti-freeze to stop delicate cells being damaged by the cold. All of these winter survival strategies ensure that the trees around us live for centuries. Without dormancy, they would never be able to survive the harsh conditions that winter throws at them. So next time you stop to admire a deciduous tree this winter, spare a thought for the remarkable things it is doing in its struggle for survival.” Ollie ~ Creative Landscapes
The lord and master of the Cambrian seas was the undulating predator Anomalocaris. It was likely highly efficient, and now we are learning, highly visual. It was considerably larger than any other creature in those shallow seas and must have evoked fear with nothing more than its shadow. Carnivory and predation were two key elements ushering in evolution and this generally requires vision as a principal sensory input. Sure enough, Anomalocaris had two eyes on stalks probably giving it a wide visual field. But, until recently, we have known very little about its visual capabilities and mechanisms. That has changed. In a well-considered manuscript, Paterson et al describes fossils of the eye of Anomalocaris. From this work we now know that that this magnificent animal, probably the first in the line of apex predators of these shallow seas, had a compound eye that, in many ways, resembled the eye of today’s dragonfly. Anomalocaris had perhaps as many as 16,000 hexagonal facets (individual units of the eye called ommatidia) in each eye and probably good vision. For reference, extant dragonflies have approximately 25,000 ommatidia and surprisingly good vision. Although I doubt that this Anomalocaris had vision good to read the newspaper, its vision would have been very good, at least in bright light. Its compound eyes were likely of the simplest and most common design—the apposition compound eye. This eye would require a great deal of light, and restrict the animal to a diurnal lifestyle. It would have been restricted to the rather bright light environments such as those found in a coral reef of today. Almost certainly Anomalocaris would have had a wide field of vision and surprisingly sharp vision for smaller prey—just like a dragonfly. With its anterior “arms” for capture and its mouth located beneath the proximal portion of its body, this first top predator would have had few competitors. Its prey species were soft bodied as it was as well. Such predation would inevitably drive the predator-prey “arms race” and could well have been instrumental as the stimulus for the evolution of hard shell-like bodies. With Permission of the Royal Ontario Museum and Parks Canada © ROM-Photo Credit: J.B. Caron. Paterson JR, Barcia-Bellido DC, Lee, MSY, et al: Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes. Nature 2011; 480: 237-240.
\|http://ghr.nlm.nih.gov/ A service of the U.S. National Library of Medicine®\| Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 14, one copy inherited from each parent, form one of the pairs. Chromosome 14 spans more than 107 million DNA building blocks (base pairs) and represents about 3.5 percent of the total DNA in cells. Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 14 likely contains 800 to 900 genes that provide instructions for making proteins. These proteins perform a variety of different roles in the body. Genes on chromosome 14 are among the estimated 20,000 to 25,000 total genes in the human genome. Genetics Home Reference provides information about the following genes on chromosome 14: Many genetic conditions are related to changes in particular genes on chromosome 14. This list of disorders associated with genes on chromosome 14 provides links to additional information. Genetics Home Reference provides information about the following conditions related to genes on chromosome 14: Changes in the structure or number of copies of a chromosome can also cause problems with health and development. The following chromosomal conditions are associated with such changes in chromosome 14. Rearrangements (translocations) of genetic material between chromosome 14 and other chromosomes have been associated with several types of cancer. These chromosome abnormalities are somatic, which means they are acquired during a person's lifetime and are present only in certain cells. Studies show that these translocations disrupt genes that are critical for keeping cell growth and division under control. Unregulated cell division can lead to the development of cancer. Translocations involving chromosome 14 have been found in cancers of blood-forming cells (leukemias), cancers of immune system cells (lymphomas), and several related diseases. For example, Burkitt lymphoma, a cancer of white blood cells that occurs most often in children and young adults, is related to a translocation between chromosomes 8 and 14. Another type of lymphoma, called follicular lymphoma, is often associated with a translocation between chromosomes 14 and 18. In a cancer of white blood cells called multiple myeloma, the presence of a translocation between chromosomes 4 and 14 is associated with a more aggressive form of the disease. A deletion of genetic material from part of the long (q) arm of chromosome 14 can cause FOXG1 syndrome, which is a rare disorder characterized by impaired development and structural brain abnormalities. The region of chromosome 14 that is deleted includes the FOXG1 gene as well as several neighboring genes. Depending on which genes are involved, affected individuals may have additional signs and symptoms, including distinctive facial features and a missing connection between the left and right halves of the brain (a structure called the corpus callosum). The protein normally produced from the FOXG1 gene plays an important role in brain development before birth, particularly in a region of the embryonic brain known as the telencephalon. The telencephalon ultimately develops into several critical structures, including the the largest part of the brain (the cerebrum), which controls most voluntary activity, language, sensory perception, learning, and memory. A loss of the FOXG1 gene disrupts normal brain development starting before birth, which appears to underlie the structural brain abnormalities and severe developmental problems characteristic of FOXG1 syndrome. It is unclear how the loss of additional genes contributes to the signs and symptoms of the condition. Ring chromosome 14 syndrome is caused by a chromosomal abnormality known as a ring chromosome 14 or r(14). A ring chromosome is a circular structure that occurs when a chromosome breaks in two places and its broken ends fuse together. People with ring chromosome 14 syndrome have one copy of this abnormal chromosome in some or all of their cells. Researchers believe that several critical genes near the end of the long (q) arm of chromosome 14 are lost when the ring chromosome forms. The loss of these genes is likely responsible for several of the major features of ring chromosome 14 syndrome, including intellectual disability and delayed development. Researchers are still working to determine which missing genes contribute to the signs and symptoms of this disorder. Epilepsy is a common feature of ring chromosome syndromes, including ring chromosome 14. There may be something about the ring structure itself that causes epilepsy. Seizures may occur because certain genes on the ring chromosome 14 are less active than those on the normal chromosome 14. Alternately, seizures might result from instability of the ring chromosome in some cells. A rare condition known as terminal deletion 14 syndrome causes signs and symptoms similar to those of ring chromosome 14 syndrome. Terminal deletion 14 syndrome is caused by the loss of several genes at the end (terminus) of the long (q) arm of chromosome 14. In addition, some people with terminal deletion 14 syndrome have a loss or gain of genetic material from another chromosome. People with this condition may have weak muscle tone (hypotonia), a small head (microcephaly), frequent respiratory infections, developmental delay, and learning difficulties. Other changes in the number or structure of chromosome 14 can have a variety of effects, including delayed growth and development, distinctive facial features, and other health problems. Several different changes involving chromosome 14 have been reported. These include an extra copy of a segment of chromosome 14 in every cell (partial trisomy 14), an extra copy of the entire chromosome in only some of the body's cells (mosaic trisomy 14), and deletions or duplications of part of chromosome 14. Full trisomy 14, an extra copy of the entire chromosome 14 in all of the body's cells, is not compatible with life. Health problems can also result from a chromosome abnormality called uniparental disomy (UPD). UPD occurs when people inherit both copies of a chromosome from one parent instead of one copy from each parent. The long arm of chromosome 14 contains some genes that are active only when inherited from the mother, and other genes that are active only when inherited from the father. Therefore, people who have two paternal copies or two maternal copies of chromosome 14 are missing some functional genes and have an extra copy of others. When both copies of chromosome 14 are inherited from the mother, the phenomenon is known as maternal UPD 14. Maternal UPD 14 is associated with premature birth, slow growth before and after birth, short stature, developmental delay, small hands and feet, and early onset of puberty. When both copies of the chromosome are inherited from the father, the phenomenon is known as paternal UPD 14. Paternal UPD 14 is associated with an excess of amniotic fluid (which surrounds the baby before birth); an opening in the wall of the abdomen; distinctive facial features; a small, bell-shaped chest with short ribs; and developmental delay. Both maternal UPD 14 and paternal UPD 14 appear to be rare. Geneticists use diagrams called ideograms as a standard representation for chromosomes. Ideograms show a chromosome's relative size and its banding pattern. A banding pattern is the characteristic pattern of dark and light bands that appears when a chromosome is stained with a chemical solution and then viewed under a microscope. These bands are used to describe the location of genes on each chromosome. You may find the following resources about chromosome 14 helpful. These materials are written for the general public. You may also be interested in these resources, which are designed for genetics professionals and researchers. cancer ; cell ; cell division ; cerebrum ; chromosome ; corpus callosum ; deletion ; developmental delay ; disability ; DNA ; embryonic ; epilepsy ; gene ; hypotonia ; immune system ; imprinting ; inherit ; inherited ; lymphoma ; maternal ; microcephaly ; mosaic ; multiple myeloma ; muscle tone ; myeloma ; perception ; protein ; puberty ; respiratory ; short stature ; stature ; syndrome ; translocation ; trisomy ; uniparental disomy ; white blood cells You may find definitions for these and many other terms in the Genetics Home Reference Glossary. The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
Why is the Republic of Indonesia made of 17,508 islands? Around the Pacific Rim is Indonesia, a nation built from the dotted volcanoes of an island arc. Indonesia is distinctive for its rich volcanic soil, tropical climate, tremendous biodiversity, and volcanoes. These volcanoes are in Java, Indonesia. Landforms from Lava Volcanoes and Vents The most obvious landforms created by lava are volcanoes, most commonly as cinder cones, composite volcanoes, and shield volcanoes. Eruptions also take place through other types of vents, commonly from fissures (Figure below). The eruptions that created the entire ocean floor are essentially fissure eruptions. A fissure eruption on Mauna Loa in Hawaii travels toward Mauna Kea on the Big Island. Viscous lava flows slowly. If there is not enough magma or enough pressure to create an explosive eruption, the magma may form a lava dome. Because it is so thick, the lava does not flow far from the vent. (Figure below). Lava domes are large, round landforms created by thick lava that does not travel far from the vent. Lava flows often make mounds right in the middle of craters at the top of volcanoes, as seen in the Figure below. Lava domes may form in the crater of composite volcanoes as at Mount St. Helens A lava plateau forms when large amounts of fluid lava flow over an extensive area (Figure below). When the lava solidifies, it creates a large, flat surface of igneous rock. Layer upon layer of basalt have created the Columbia Plateau, which covers more than 161,000 square kilometers (63,000 square miles) in Washington, Oregon, and Idaho. Lava creates new land as it solidifies on the coast or emerges from beneath the water (Figure below). Lava flowing into the sea creates new land in Hawaii. Over time the eruptions can create whole islands. The Hawaiian Islands are formed from shield volcano eruptions that have grown over the last 5 million years (Figure below). The island of Hawaii was created by hotspot volcanism. You can see some of the volcanoes (both active and extinct) in this mosaic of false-color composite satellite images. Landforms from Magma Magma intrusions can create landforms. Shiprock in New Mexico is the neck of an old volcano that has eroded away (Figure below). The volcanic neck is the remnant of the conduit the magma traveled up to feed an eruption. The aptly named Shiprock in New Mexico. - Landforms created by lava include volcanoes, domes, and plateaus. - New land can be created by volcanic eruptions. - Landforms created by magma include volcanic necks and domes. Use this resource to answer the questions that follow. 1. What type of lava is produced by volcanoes? 2. How did the columns in the video form? 3. How was Fingal's cave formed? 4. Describe how the basalt lava flows? 5. How does basalt behave when it has a lot of gas trapped within it? 1. What is Shiprock and how did it form? 2. How do lava plateaus form? 3. What types of landforms are created by very viscous magma?
This site allows you to plot 11 years worth of sunspot numbers centered on any date between 1755 and the present. Great for retrieving sunspot data! The Spinning Sun An activity for you to determine the solar rotation rate based upon the movement of sunspots. Daily observations and counts of sunspots were started at the Zurich Observatory in 1749 and, with the help of other observatories, continuous observations have been obtained since 1849. Monthly averages of the sunspot numbers show that the number of sunspots visible on the Sun waxes and wanes with an approximate 11-year cycle. Visit this site to find graphs and charts of sunspot activity, including current ones updated monthly. Note, however, that the "Sunspot Number" referred to in these graphs is not a count of sunspots, but rather a number adjusted to take into account the number of groups visible, the number of individual spots visible, and differences between observers. The next reference describes how the number is determined. By David H. Hathaway of the NASA/Marshall Space Flight Center. What is the The abundance of sunspots on the Sun varies on timescales from a few hours to many years. Historically, an index called the 'sunspot number' has been used to quantify the abundance of spots. The index is still in wide use today. This site explains how the "sunspot number" is computed. Want to track solar activity? The Paderborn Public Observatory in Germany hosts a non-profit amateurs club whose main activity is solar observation. The club has established the INTER-SOL Programme (ISP) which is an addition to, but different from, the usual method of monitoring and classifying sunspots. About 50 stations, amateurs as well as professionals throughout the world contribute their data to INTER-SOL. Several techniques are used to predict the amplitude of a sunspot cycle during the time before sunspot minimum. Relationships have been found between the size of the next cycle maximum and the length of the previous cycle, as well as the level of activity at sunspot minimum and the size of the previous cycle. Among the most reliable techniques are those that use the measurements of changes in the Earth's magnetic field at, and before, sunspot minimum. These changes in the Earth's magnetic field are known to be caused by solar storms but the precise connections between them and future solar activity levels is still uncertain. Marshall Space Flight Center Galileo's View of Sunspots Galileo was not the first to observe sunspots (the Chinese earned that distinction thousands of years before), but Galileo was the first to study sunspots and their movements through a telescope. He carefully sketched what he saw. Some refuted his drawings, claiming the black spots were unknown planets crossing the disk. But Galileo was able to prove the spots were on the Sun (see Galileo's Proof and that of another scientist Wilsons Sunspot Sketchs at Mt. Wilson the Sunspot Quiz! These sets of questions test your knowledge of sunspots.
Magnetic Resonance Imaging (MRI) Magnetic resonance imaging (MRI) is a noninvasive medical test that uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. The images can then be examined on a computer monitor, printed or copied to CD. MRI does not use ionizing radiation (X-rays). The detailed images from an MRI allow physicians to better evaluate various parts of the body and certain diseases that may not be assessed adequately with other imaging methods such as X-ray, ultrasound or computed tomography (CT).
Exponential model is associated with the name of Thomas Robert Malthus (1766-1834) who first realized that any species can potentially increase in numbers according to a geometric series. For example, if a species has non-overlapping populations (e.g., annual plants), and each organism produces R offspring, then, population numbers N in generations t=0,1,2,... is equal to: When t is large, then this equation can be approximated by an exponential function: There are 3 possible model outcomes: Parameter r is called: - Population exponentially declines (r < 0) - Population exponentially increases (r > 0) - Population does not change (r = 0) "Instantaneous rate of natural increase" and "Population growth rate" are generic terms because they do not imply any relationship to population density. It is better to use the term "Intrinsic rate of increase" for parameter r in the logistic model rather than in the exponential model because in the logistic model, r equals to the population growth rate at very low density (no environmental resistance). - Malthusian parameter - Intrinsic rate of increase - Instantaneous rate of natural increase - Population growth rate Assumptions of Exponential Model: However, exponential model is robust; it gives reasonable precision even if these conditions do not met. Organisms may differ in their age, survival, and mortality. But the population consists of a large number of organisms, and thus their birth and death rates are averaged. - Continuous reproduction (e.g., no seasonality) - All organisms are identical (e.g., no age structure) - Environment is constant in space and time (e.g., resources are unlimited) Parameter r in the exponential model can be interpreted as a difference between the birth (reproduction) rate and the death rate: where b is the birth rate and m is the death rate. Birth rate is the number of offspring organisms produced per one existing organism in the population per unit time. Death rate is the probability of dying per one organism. The rate of population growth (r) is equal to birth rate (b) minus death rate (m). Applications of the exponential model - microbiology (growth of bacteria), - conservation biology (restoration of disturbed populations), - insect rearing (prediction of yield), - plant or insect quarantine (population growth of introduced species), - fishery (prediction of fish dynamics).
by Leanne Gluck, Director of Social Impact At 3D Systems, we believe that imparting digital literacy to the next generation requires more than simply putting 3D printers in classrooms. To become digitally literate, students must engage with 3D technology in a meaningful way. They must do more than download and print files; they must explore the design process itself and all the engineering applications and considerations that go along with it. Imparting digital literacy requires an infrastructure of curriculum, training and support. We have found that a path of study combining 3D scanning, 3D design and 3D printing allows for ideation, problem solving and the examination of new ideas. It not only teaches students technical skills like CAD and CAM design, but critical thinking, collaboration and communication. As we move towards a competitive future with highly valued technical skills, equipping students with the tools and skill sets they need becomes increasingly more critical for their success. And yet, for many educators the desire to help their students is obstructed by confusion over where to begin. Although they can clearly see the importance of digital literacy, its newness makes it intimidating. Recognizing this, 3D Systems has partnered with STEAMTrax to gather the resources necessary to integrate and facilitate a curriculum that ties together engineering and 3D printing technology with a core academic base in science, math, language arts, social studies, and art. STEAMTrax engages elementary and middle school students in relevant learning scenarios that are infused with 3D technology, and includes convenient kits to jumpstart classrooms with the necessary materials for each module. Think STEAMTrax could be right for your classroom? Click here to learn more!
The process of altering an organism’s genetic make-up, to ensure that it will have certain characteristics, is known as genetic modification or genetic engineering. It has already been applied to plants and animals for many years. Even though genetic modification can be used to cure life threatening diseases, many argue that it is immoral to use it on humans as there is the possibility of creating superhumans, and potentially even changing the entire species. Regardless of personal opinions about genetic modification, however, there is no doubt that the effects of altering genes can be very interesting. Some of these include: Genetic Modification in Animals Cloning – In 1996, Dolly was the first sheep ever to be cloned, meaning that a genetically identical copy of a sheep was produced using scientific methods. Even though Dolly’s ‘birth’ caused a mixed public reaction, she lived happily until 2003 when she had to be euthanised due to extremely painful arthritis. Glow-in-the-Dark Cats – Though most people are unable to understand the reason behind the experiment, in 2007, a team of scientists created one cat that was able to glow-in-the-dark. They subsequently used it to clone several others. Cows with Less Flatulence – Whenever a cow passes gas, methane is released into the air. This chemical contributes to global warming, prompting genetic modification of cows so that they will have less flatulence and therefore help to preserve the environment. Faster Growing Salmon – A popular source of food worldwide, salmon are unable to naturally produce growth hormones throughout the entire year. Scientists have found a way to modify the species, facilitating a growth rate that is twice as fast as normal. Genetic Modification in Plants Pollution Fighting Trees – The University of Washington modified polar trees allowing them to absorb polluted water and clean it, before releasing it back into the air. This is another method aimed at helping to protect the environment. Golden Rice – There are countries in the world where the majority of citizens are unable to make healthy food choices. Scientists created a rice which contains beta-carotene, which is also found in carrots and gives them their orange colour. This rice will provide a high dose of Vitamin A, to boost the immune system, whenever it is consumed. Faster Growing Trees – An increased demand for wood has resulted in the production of trees that are able to ward off biological attacks, grow quicker and are stronger. These produce a better wood supply for construction and other projects. Corn with Insecticide – Corn is grown on a large scale worldwide, and provides food for many people. Farmers would normally manually spray the crops, to ensure that insects do not destroy them. Genetic modification has resulted in a strand of corn that is able to produce a poison that kills insects. Since the plant cannot be selective about the insects that it kills, however, both the beneficial ones, such as butterflies, and the destructive ones are repelled.
The loss of sight in cave dwelling species is widely known. We presume that since sight in utter darkness has no fitness value, the mutation of a gene critical to the development of the sense of sight is not selected against. Over time, any population living in darkness will eventually experience experience such mutations, and these mutations can reach fixation. Astyanax mexicanus: Top is the surface, sighted form, bottom is the cave-dwelling, blind form. From the Jeffery Lab.Beyond this, we may hypothesize that a mutation “turning off” sight could be beneficial. By definition, an adaptation (such as sight) has a cost. When a trait that is adaptive is no longer adaptive, individuals with that trait “turned off” should experience an increase in fitness. It may also be the case, however, that such an increase in fitness is so small that it may be irrelevant. This line of thinking needs further investigation and what one finds in such an investigation may vary a lot from system to system. For example, a mutation that simply causes a particular protein to no longer be produced in what would have been a small quantity would save the individual with that mutation the use of a few tens of thousands of amino acids over some fixed period of time. This would have very little fitness value. But if a system is exploitable by a pathogen … such as a receptor site on a cell used by a common virus … turning that gene off may have enormous benefits. But this is a bit of a digression from the research at hand. Borowsky, in his paper “Restoring sight in blind cavefish,” provides a test case for how we think evolution works. In Mexico, the species Astyanax mexicanus, is known to exist in 29 distinct populations. Genetic studies indicate that the turning off of the sense of sight in these fish has involved a deleterious (as in loss of function) of genes in at least three different lineages, or to put it a different way, sightlessness has evolved three or more separate times in these Mexican blind cavefish. When Borowsky cross breeds some of these cavefish, crossing them between these populations, he gets a certain percentage of fish that have functional, if not fully developed, eyes. This should not be at all surprising. Several different genes are involved in the development of sight, so by cross breeding strains that have experienced mutations in different genes, one would expect a certain number of offspring to have a set of functioning genes sufficient to make the sense of sight develop at least to some extent. When Borowsky breeds the blind cavefish with the non-blind version of this fish (“surface fish”) he gets restoration of the sense of sight in all of the offspring. F1 hybrids between surface fish and cave fish have smaller eyes than surface fish, but are fully visual, even into adulthood … Thus, one surface allele at each of the population-specific eye loci is sufficient for restoring vision. This is also expected, although not necessarily inevitable (This depends on the dosage required for each genetically coded step in the development and function of sight). It seems to me that one could test the hypothesis mentioned above that turning off any fitness-free gene is adaptive. If simple production of unused proteins is costly, the rate at which particular genes are found to be turned off should be correlated with that cost. Perhaps the genes coding for longer proteins, or proteins that are produced more often in a particular system, should be more likely turned off. Or, some measure of the total mass of amino acids turned into proteins when a gene functions, should be correlated to the likelihood of having a gene turned off. At a most basic level, one would need to show that the mutant genes are in fact turned off and are not simply producing a non-functional protein. In short, this study (and others by this and other research teams) demonstrates in empirical reality what is expected from commonly held evolutionary theory. Creationists often cite blind cave dwelling organisms as evidence against evolution, because, they say, it is “devolution.” This point of view is absurd, and relies on a teleological view of, in this case, teleost (bony fish) evolution. Darwin wrote about cave blindness and disuse, and through various observations notes the potential complexity oif the problem: It is well known that several animals, belonging to the most different classes, which inhabit the caves of Styria and of Kentucky, are blind. In some of the crabs the foot-stalk for the eye remains, though the eye is gone; the stand for the telescope is there, though the telescope with its glasses has been lost. As it is difficult to imagine that eyes, though useless, could be in any way injurious to animals living in darkness, I attribute their loss wholly to disuse. In one of the blind animals, namely, the cave-rat, the eyes are of immense size; and Professor Silliman thought that it regained, after living some days in the light, some slight power of vision. In the same manner as in Madeira the wings of some of the insects have been enlarged, and the wings of others have been reduced by natural selection aided by use and disuse, so in the case of the cave-rat natural selection seems to have struggled with the loss of light and to have increased the size of the eyes; whereas with all the other inhabitants of the caves, disuse by itself seems to have done its work. [On the Origin of Species..., 1859, pp 137-138] You might be wondering how these fish got into these caves to begin with. I can’t describe the exact process for the fish studied in this paper, but there is a general way in which this can happen. Underground lakes or streams in caves may be connected to each other during less arid periods, in some cases running from the deeps of large lakes that later try up almost entirely. In this way, a continuous population in a river or lake is broken into relict populations that are separate from each other and perhaps living in habitats that are different from the original, continuous habitat, and possibly different from each other as well. Under these conditions evolution’s just gotta happen. BOROWSKY, R. (2008). Restoring sight in blind cavefish. Current Biology, 18(1), R23-R24. DOI: 10.1016/j.cub.2007.11.023
Warp-knitted mosquito nets help in the fight against malaria and the spread of the Zika virus Some tiny insects are currently causing a great deal of concern, especially among pregnant women. The yellow-fever and tiger mosquitoes can pass on the zika virus and are suspected of causing microcephaly, a developmental disorder that affects unborn babies. The results of the zika virus infection are miscarriages and babies born with small heads, who are likely to be severely mentally handicapped. According to the World Health Organization (WHO), 33 countries had already been affected by the spread of this dangerous virus by February of this year, with Brazil and Colombia being the worst affected countries. Health experts have been studying female anopheles mosquitoes for some time. These transfer the malaria pathogens and are just as dangerous to humans. A child dies every 30 seconds from the tropical disease known as swamp fever or malaria. But malaria is also responsible for a high number of deaths among adults. This disease is prevalent in 106 countries globally and is a threat to more than half of the world’s population. The WHO recommends that all the public health authorities worldwide use insect-proof nets having long-lasting insecticidal effects (LLINs) to reduce the incidence of malaria quickly and effectively. These fine-meshed textiles are the best method of prevention and are easy to use, effective and cheap. KARL MAYER’s warp-knitting machines can be used to efficiently produce these nets, which provide a high level of protection. Mechanical and chemical protection The nets must have a specific construction to provide safe and reliable protection against mosquito bites. The required textile parameters include a defined number of mesh holes and this should be 156 holes/inch2 or 25 holes/cm2 when using polyester (PES) filament yarns. This value is recommended by the WHO and firstly, guarantees mechanical resistance to insect bites and secondly, ensures that there is adequate air circulation suitable for a tropical climate. Modern mosquito nets meet this requirement by having stitch densities of 8 to 10 holes/cm when using polyester multifilament yarns, depending on the construction. The textile nets must also have a specific strength, so that the mosquitoes cannot make holes in them. /1/ In addition to the mechanical protection provided by the textile construction, mosquito nets also provide chemical protection by treating them with a contact insecticide. The most frequently used pyrethroids are applied to the nets by a standard impregnation process or by long lasting impregnation (LLI). Products that have been treated by the standard impregnation process lose their effectiveness after six months and after every wash, and the insecticide has to be re-applied regularly. LLI mosquito nets, on the other hand, can be used for more than three years and washed up to twenty times. Warp-knitted mosquito nets are mainly produced on two-bar tricot machines, such as the TM 2 and HKS 2-M. KARL MAYER’s machines offer the best in terms of quality and productivity. The machines operate in gauges E 28 or E 32 when working polyester filament yarns. If polyethylene (HDPE) monofilament yarns are used, they are worked usually in gauge E 14, but slight variations above or below this are also feasible. The two types of yarns have different constructions and properties and also differ as to how they are used in conjunction with the insecticide. Whilst the warp-knitted polyester textile is impregnated with the chemical at the finishing stage, the agent is already present in the HDPE at the granulate stage. Despite their high operating speeds, KARL MAYER’s tricot machines do not compromise on quality. The machines offer maximum precision and thus meet stringent requirements in terms of dimensional stability and uniformity of the mesh openings, tear resistance and weight per unit area. This attention to detail is definitely worth it, since any variations in the specified parameters can cost lives. In addition to tricot machines, raschel machines having three guide bars can also be used to produce certain products. /1/ Specifications for Netting Materials, Roll Back Malaria Cabinet Project, WHO, 2001.Back to overview
The cellular process of building the cell membrane from saturated fatty acids results in patches of hardened membrane in which molecules are frozen, under healthy conditions, this membrane should be flexible and the molecules fluidic. Also, researchers found that using this technique could have significant impact on both the understanding and treatment of obesity, diabetes, and cardiovascular disease. The stiff, straight, long chains of saturated fatty acids rigidify the lipid molecules and cause them to separate from the rest of the cell’s membrane. As more saturated fatty acids enter the cell, those “solid like clusters” grow larger, creating increasing inelasticity of the membrane and gradually damaging the entire cell. Lipid molecules made from unsaturated fatty acids on the other hand bear a kink in their chains, Addition of unsaturated fatty acids could melt the membrane frozen clusters by saturated fatty acids, new mechanism related to this can partly explain the beneficial effect of unsaturated fatty acids and how unsaturated fats like those from fish oil can be protective in some lipid disorders. Later, it revealed an unknown toxic physical state of the saturated lipid accumulation inside the cellular membranes. The behavior of saturated fatty acids once they have entered cells contributes to major and often deadly diseases, visualizing how fatty acids are contributing to lipid metabolic disease gives us the direct physical information we need to begin looking for effective ways to treat them. We can find away to block the toxic lipid accumulation, the finding has the potential to really impact, public health, especially for lipid related diseases. Columbia University. (2017, December 1). How saturated fatty acids damage cells: Observations of saturated and unsaturated fatty acid behavior could impact public health. ScienceDaily. Retrieved December 1, 2017 from www.sciencedaily.com/releases/2017/12/171201181545.htm Guenel, J. (2017, December 1 ). New Imaging Study Reveals How Saturated Fatty Acids Damage Cells. Retrieved December 01, 2017, from https://eurekalert.org/multimedia/pub/157412.php
The wilderness is vast and varied, home to millions of animal species. For ecologists, identifying and describing those animals is key to successful research. That can prove to be a tall order — but artificial intelligence may be able help. In a new report out this week, researchers show how they trained a deep learning algorithm to automatically identify, count, and characterize animals in images. The system used photographs captured from motion-sensing camera traps, which snap pictures of the animals without seriously disturbing them. “We have shown that we can use computers to automatically extract information from wildlife photos, such as species, number of animals, and what the animals are doing.” Margaret Kosmala, a research associate at Harvard University, told Digital Trends. “What’s novel is that this is the first time it’s been shown that it’s possible to do this as accurately as humans. Artificial intelligence has been getting good at recognizing things in the human domain — human faces, interior spaces, specific objects if well-positioned, streets, and so forth. But nature is messy and in this set of photos, the animals are often only partially in the photo or very close or far away or overlapping. As an ecologist, I find this very exciting because it gives us a new way to use technology to study wildlife over broad areas and long time spans.” The researchers used images captured and collected by Snapshot Serengeti, a citizen science project with stealth wildlife cameras spread throughout Tanzania. From elephant to cheetahs, Snapshot Serengeti has gathered millions of wildlife photographs. But the images themselves aren’t as valuable as the data contained within the frame, including details like number and type of animals. Automated identification and descriptions has a lot of benefits for ecologists. For years, Snapshot Serengeti used to crowdsource the task of describing wildlife images. With the help of some 50,000 volunteers, the group labeled over three million images. It was this treasure trove of labeled imagery that the researchers used to train their algorithm. Now, rather than turn to citizen scientists, researchers may be able to assign the laborious task to an algorithm, which can quickly process the photographs and label their key details. “Any scientific research group or conservation group that is trying to understand and protect a species or ecosystem can deploy motion-sensor cameras in that ecosystem,” Jeff Clune, a professor of computer science at the University of Wyoming, said. “For example, if you are studying jaguars in a forest, you can put out a network of motion-sensor cameras along trails. The system will then automatically take pictures of the animals when they move in front of the cameras, and then the A.I. technology will count the number of animals that have been seen, and automatically delete all the images that were taken that do not have animals in them, which turns out to be a lot because motion-sensor cameras are triggered by wind, leaves falling, etcetera.” A paper detailing the research was published this week in the journal the Proceedings of the National Academy of Sciences. - HP unveils new IPS Black monitor with one key new feature - New VESA display standard makes it easier to pick a monitor - Chromebooks might get another great feature from Windows laptops - All the new Chromebook features quietly announced at Google I/O - Finishing touch: How scientists are giving robots humanlike tactile senses
From Wikipedia, the free encyclopedia Sodium bicarbonate is the chemical compound with the formula NaHCO3. Because it has long been known and is widely used, the salt has many other names including sodium hydrogencarbonate, sodium bicarb, baking soda, bread soda, cooking soda, bicarb soda, saleratus or bicarbonate of soda. It is soluble in water. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slight alkaline taste resembling that of sodium carbonate. It is a component of the mineral natron and is found dissolved in many mineral springs. The natural mineral form is known as nahcolite. It is also produced artificially. NaHCO3 is mainly prepared by the Solvay process, which entails the reaction of sodium chloride, ammonia, and carbon dioxide in water. It is produced on the scale of about 100,000 ton/year (year: 2001). Commercial quantities of baking soda are also produced by this method: soda ash, mined in the form of the ore trona, is dissolved in water and treated with carbon dioxide. Sodium bicarbonate precipitates as a solid from this method: Na2CO3 + CO2 + H2O → 2 NaHCO3 NaHCO3 is a salt which consists of the ions Na+ and the bicarbonate anion, HCO3-. In aqueous solution, these ions are separated. Furthermore the bicarbonate anion forms some hydroxide, which results in its solutions being mildly alkaline: HCO3- → CO2 + OH- CO2 + 2NaOH → Na2CO3 + H2O It also reacts with water during hydrolysis Reaction of sodium hydroxide with carbon dioxide NaHCO3 may be obtained by the reaction of carbon dioxide with sodium hydroxide : The initial reaction produces sodium carbonate: CO2 + 2NaOH → Na2CO3 + H2O It reacts further with carbon dioxide and water to produce sodium hydrogen carbonate, which precipitates out of solution: Na2CO3 + CO2 + H2O → 2NaHCO3 These reactions are reversible. Treatment of sodium bicarbonate with an acid, releases carbon dioxide and water: NaHCO3 + HCl → NaCl + H2O + CO2 (gas) NaHCO3 + CH3COOH → CH3CO2Na + H2O + CO2 (gas) Above 60 °C, it gradually decomposes into sodium carbonate, water and carbon dioxide. The conversion is fast at 200 °C: 2NaHCO3 → Na2CO3 + H2O + CO2 Most bicarbonates undergo this dehydration reaction. Further heating converts the carbonate into the oxide: Na2CO3 → Na2O + CO2 These conversions are relevant to the use of NaHCO3 as a fire-suppression agent (“BC powder”) in some dry powder fire extinguishers. The word saleratus, from Latin sal æratus meaning “aerated salt”, was widely used in the 19th century for both sodium bicarbonate and potassium bicarbonate. The term has now fallen out of common usage. For neutralization of acids The reaction of acids with sodium bicarbonate is a common method for neutralizing acid spills. The advantage to this method is that one can use excess sodium carbonate, which is relatively innocuous. The neutralization process is signaled by the release of gaseous CO2. A wide variety of applications follow from its neutralization properties including ameliorating the effects of white phosphorus in incendiary bullets, from spreading inside a soldier’s afflicted wounds. Military Application It is commonly used to increase the pH and total alkalinity of the water for pools and spas. Sodium bicarbonate can be added as a simple solution for restoring the pH balance of water that has a high level of chlorine. It is sometimes used in septic tanks to control pH and bacteria. It neutralizes battery acid (H2SO4): 2 NaHCO3 + H2SO4 → Na2SO4 + 2 H2O + 2 CO2 Baking soda has many uses. - As a deodorizer - An absorbent for moisture and odors e.g; an open box can be left in a refrigerator for this purpose. However, according to one source, baking soda does not actually absorb odors well when used in a refrigerator. - To help relief itching due to bacterial infections As pest control - It may be used to kill fleas, ants, and other insect pests; the powder abrades their exoskeletons. If it is applied to a pet’s fur, it should be rinsed off to prevent skin problems. - Can be used to kill crab grass. Must be used repeatedly to control but is effective. Dampen area then sprinkle lightly, too much may harm desired grass temporarily. - Cosmetic uses - As a cleaning agent - A paste from baking soda can be very effective when used in cleaning and scrubbing. - A solution in warm water will remove the tarnish from silver when the silver is in contact with a piece of aluminum foil. - Cleans brushes and combs to prevent residues. - Use to clean juice, wine, and coffee stains. - Pouring 1 cup of baking soda down a drain and following with 1/2 gallon of vinegar will degrease the drain. - It is used as a fabric softener in laundry. - It is used to test garden soil for acidity. If it bubbles, the soil is too acidic. - If mixed with super glue, it makes a suitable filling for cracks in walls. - Baking soda can be used as a low-cost alternative to raise pH in swimming pools. - As a desiccant, sprinkle on wet pages of books and then put them out to dry under the sun. - Sodium bicarbonate is used in BC Dry Chemical fire extinguishers as an alternative to the corrosive ammonium phosphate in ABC extinguishers. The alkali nature of Sodium Bicarbonate makes it the only dry powder, excluding Purple-K, agent allowed for use on commercial deep fat fryers, the agent forms a crust over the surface similar to the effects of a wet chemical. - Sodium bicarbonate is often used in the pharmaceutical industry as an additive to cell culture media. It acts as a weak buffer. Sodium bicarbonate is considered to be relatively safe, however consumption of large amounts should be avoided. See MSDS.
Rationing of food and goods by civilians allowed the armies to receive desperately needed supplies. For as long as humans have gone to war or faced natural disasters, they have prepared for those disasters in some form or another. Complacency means death, and early civilizations understood this more often than not. From government stockpiles of food, supplies, and weapons, to lone citizens and families hunkering down in bunkers deep in the mountains, humanity prepares to survive even if civilization does not. Before the age of regeneration and frozen foods, or even canning, people worked to make sure they would have food when times were hard, usually during the winter. During the Middle Ages, animals were slaughtered and their meats smoked and salted to last through the winter and avoid the expense of feeding the animals during lean times. It also meant that come spring, when military campaigns started, the remaining animals would be young and easier to hide or flee from battle. Into the modern era, King Louis XVI of France encouraged planting the New World crop, potatoes, over wheat because while wheat fields burned and became trampled underfoot during battle, the humble potato survived. Though initially unpopular with the French peasantry, the plant increased food production by fifteen percent. As humanity industrialized and worked to create mass mobilization and ever more destructive means of killing each other, governments created new ways to prepare for war and disaster. Organizations such as the Red Cross rallied to provide supplies, funds, and relief for wounded soldiers and widows. When the world erupted into global wars during the twentieth century, people rallied to the causes of their respective governments. Rationing of food and goods by civilians allowed the armies to receive desperately needed supplies. Such rationing reached desperation levels for the Germans during the Great War, who ran out of nearly everything thanks to the British blockade. World War II would stretch many governments’ resources to their limits. Though by war’s end it would produce surpluses of most war materiel, concerns over food production once again meant rationing. To ease the burden for households across the country, the US government encouraged the growth of “Victory Gardens.” Twenty million Americans turned spare plots of land across the country into vegetable gardens. Not only did they grow fruits and vegetables for home use, but they also preserved the resulting produce. All told, the output of the Victory Gardens equaled domestic produce production, providing vital food at home and allowing agricultural production to go to the front lines. While some gardened for America, others, fearing bombings raids, started building bomb shelters beneath their homes. With World War II ending, the globe became gripped by fear of nuclear annihilation in the Cold War, so bomb shelters grew in popularity, both for civilians and the government and military. One of the largest such bunkers ever built by the US government was the Greenbier Resort shelter in West Virginia. Four hours from the national capital and located beneath a congressional resort, the massive bunker was designed to house the government in the event of a nuclear war. Thankfully and obviously it was never needed, but the threat of the Cold War going hot caused many to prepare underground shelters, just in case. As the Cold War dragged on, the so-called survivalists entered the stage. Rather than hunker down in a bunker, these people set the foundation for the modern “prepping” lifestyle. Though the peace of the 1990’s eroded their appeal, the ideas of emergency supplies, firearms training, and the ability to survive in the wilderness still has its adherents. Whether because of national disaster, famine, war, or the end of civilization, people and governments have long worked to proactively prepare for what might happen, and what might not happen, because it might just be too late otherwise.
Plants need certain nutrients to stay healthy and thrive. The most important plant nutrients include nitrogen, phosphorus, and potassium. These essential nutrients help plants grow strong roots, produce lush foliage, and create beautiful blooms. Plant feeding often comes across as intimidating. With hundreds, if not thousands, of possible feeding charts, growers usually do not know where to start their research. As a result, they don’t know which vitamins and minerals to prioritize. Mike Straumietis has helped growers in 110+ countries. Based on his experience, most newcomers feel overwhelmed because they have no prior knowledge of plant nutrients. Don’t worry if you find yourself in a similar predicament. To jumpstart your research, we briefly discuss essential mineral nutrients and their effects on plant growth. As a general rule, all your plant supplements should contain adequate calcium. It helps plants absorb nutrients more efficiently. Calcium is often found in limestone. This mineral is necessary for cell wall development and strengthens plant tissue. Potassium heavily supports plant development. Also called “potash,” this nutrient helps with photosynthesis, water use, and disease resistance. It supports carbon dioxide, oxygen, and water vapor absorption by regulating the opening and closing of the stomata. It should be noted that a potassium deficiency often leads to stunted growth. Plants need phosphorus for tissue development and cell division. Several Phosphorus comes from phosphate rocks or droppings from vertebrates. This Phosphorus is essential for root development, blooming, and fruiting. Mike Straumietis shares that a deficiency of this mineral will compromise weather resistance, root development, and seed growth. This nutrient is responsible for leaves and plant growth. A lack of nitrogen will result in stunted growth and yellowing leaves. Nitrogen helps plants retain the adaptive, responsive DNA needed for crop survival. It plays a crucial role in natural selection. Generally, nitrogen supplements let plants pass down positive traits like virus resistance or environment acclimation during reseeding. Magnesium helps produce chlorophyll and activates many enzymes. It is found in dolomitic limestone or magnesium sulfate Heptahydrate. You can prevent wilting and discoloration with magnesium. It helps leaves achieve richer, deeper green coloring by stimulating chlorophyll production and carbon dioxide absorption. Yellow, wilted lawns would benefit greatly from magnesium-based fertilizers. Mike Straumietis encourages growers to explore various mineral nutrients. Research their long-term effects on certain crops, and assess how you can incorporate them into your current feeding system. Test new supplements in small batches to avoid wasting resources. If, like many, you don’t have time for trial and error, you can always seek help from growers specializing in the same crops. You can even ask what fertilizers they use. Ideally, consult experienced specialists who can give you first-hand insights into different feeding systems, charts, and patterns.
What are Common Municipal Water Treatment Methods? Waterborne germs, such as Cryptosporidium, E. coli, Hepatitis A, Giardia intestinalis, and other pathogens can contaminate drinking water causing severe illness. Drinking water sources are subject to contamination and require appropriate treatment to remove disease-causing agents. Public drinking water systems use numerous methods of water treatment to provide safe drinking water for their communities. The most common steps in water treatment used by municipal water systems (mainly surface water treatment) include: Ultraviolet (UV) rays penetrate harmful pathogens in the water and destroy illness-causing microorganisms by attacking their genetic core (also known as their DNA). Coagulation and Flocculation Coagulation and flocculation are frequently the first steps in water treatment. Chemicals with a positive charge are added to the water. The positive charge of these chemicals neutralizes the negative charge of dirt and other dissolved particles in the water. When this occurs, the particles bind with the chemicals and form larger particles, called floc. During sedimentation, floc settles to the bottom of the water supply, due to its weight. This settling process is called sedimentation. Once the floc has settled to the bottom of the water supply, the clear water on top will pass through filters of varying compositions (sand, gravel, and charcoal) and pore sizes, in order to remove dissolved particles, such as dust, parasites, bacteria, viruses, and chemicals. After the water has been filtered, a disinfectant (for example, chlorine, chloramine) may be added in order to kill any remaining parasites, bacteria, and viruses to protect the water from germs when it is piped to households and businesses. Water may be treated differently in different communities depending on the quality of the water that enters the treatment plant. Typically, surface water requires more treatment and filtration than ground water because lakes, rivers, and streams contain more sediment and pollutants and are more likely to be contaminated than ground water. Some water supplies may also contain disinfecting by-products, inorganic chemicals, organic chemicals, and radionuclides. Specialized methods for controlling formation or removing them can also be part of water treatment. Household Water Treatment Even though the EPA regulates and sets standards for public drinking water, many Americans use home water treatment units to: Remove specific contaminants Take extra precautions because a household member has a compromised immune system Improve the taste of drinking water Household water treatment systems are composed of two categories: point-of-use and point-of-entry. Point-of-entry systems are typically installed after the water meter and treat most of the water entering a residence. Point-of-use systems are systems that treat water in batches and deliver water to a tap, such as a kitchen or bathroom sink or an auxiliary faucet mounted next to a tap. There are four common types of household water treatment systems: A water filter removes impurities from water by means of a physical barrier, chemical, and/or biological process. A water softener reduces the hardness of the water. A water softener typically uses sodium or potassium ions to replace calcium and magnesium ions, the ions that create “hardness.” Distillation is a process in which impure water is boiled and the steam is collected and condensed in a separate container, leaving many of the solid contaminants behind. Disinfection is a physical or chemical process in which pathogenic microorganisms are deactivated or killed. Examples of chemical disinfectants include chlorine, chlorine dioxide, and ozone. Examples of physical disinfectants include ultraviolet light, electronic radiation, and heat.
Archaeologists have figured out a lot about the moai, the giant stone heads found on Rapa Nui or Easter Island, a tiny dot of land in the Pacific Ocean administered by Chile. They know what quarries the stone came from, how they were transported across the island and even how they got their distinctive hats. But one big mystery has remained—why exactly were the giant statues placed in certain spots around the island? One group of researchers believes they have an answer. Nicola Davis at The Guardian reports archaeologists theorize the location and size of the moai and the monumental raised platforms many of them sit on, called ahu, indicate the presence of fresh water on the island, which has no above ground streams or rivers flowing across it. The theory emerged when the researchers used spatial modeling to explore the relationship between the locations of 93 of the ahu on the eastern half of the island and available resources. The team looked at the location of marine resources, mulched gardens where crops like sweet potatoes were grown and water resources including wells and seeps where drinkable but brackish freshwater flows out of the ground near the coast at low tide. The study appears in the journal PLOS One. Wherever water seeped out of the coast, the team found platforms for statues. And in areas in the interior where there were platforms but didn't seem to be any water, they found the remains of ancient wells that tapped the islands underground aquifers. The size of the statues seemed to correspond to the amount of water available as well. In areas with no water resources, there were no moai or ahu. “Every time we saw massive amounts of fresh water, we saw giant statues,” co-author Carl Lipo from Binghamton University tells Davis. “It was ridiculously predictable.” The study also contradicts the long-held idea that the inhabitants of the island suffered an ecological collapse that led to warfare between various bands and intense competition to build the statues that led to the society’s collapse. Instead, recent research indicates the inhabitants of the island were cooperative, both in the construction of the moai, which likely represented ancestors, and in sharing resources like water. “In this way, the monuments and statues of the islanders’ deified ancestors reflect generations of sharing, perhaps on a daily basis—centered on water, but also food, family and social ties, as well as cultural lore that reinforced knowledge of the island's precarious sustainability,” co-author Terry Hunt of the University of Arizona says in a press release. “And the sharing points to a critical part of explaining the island's paradox: despite limited resources, the islanders succeeded by sharing in activities, knowledge, and resources for over 500 years until European contact disrupted life with foreign diseases, slave trading, and other misfortunes of colonial interests.” But not everyone thinks the new spatial analysis explains the positioning of the ahu. Jo Anne Val Tilburg, an Easter Island researcher from the University of California, Los Angeles, tells Davis at The Guardian that the coastal water seeps were a minor resource and it’s highly unlikely the islanders would have built such massive constructions to mark them. Even if the statues aren’t related to the availability of water, they are beginning to tell a tale much different from the one spun in the past decades, most notably in Jared Diamond's popular book Collapse. It’s believed when Polynesians reached Rapa Nui around 1200 A.D. it was covered with palm trees. But the settlers brought with them non-native rats, which multiplied and ate tree seedlings, meaning the island's forests could not renew themselves. In the face of a changing environment the islanders did not descend into warfare, genocide and cannibalism, but instead adapted to the new situation, eating lots of rats, drinking brackish water and cooperating with one another to make giant statues that still amaze people around the world over 800 years later.
NCERT Solutions Class 12 Biology Chapter 4 – Reproductive Health Question 1: What do you think is the significance of reproductive health in a society? Answer Reproductive health is the total well being in all aspects of reproduction. It includes physical, emotional, behavioural, and social well being. Sexually transmitted diseases such as AIDS, gonorrhoea, etc. are transferred from one individual to another through sexual contact. It can also lead to unwanted pregnancies. Hence, it is necessary to create awareness among people, especially the youth, regarding various reproduction related aspects as the young individuals are the future of the country and they are most susceptible of acquiring sexually transmitted diseases. Creating awareness about the available birth control methods, sexually transmitted diseases and their preventive measures, and gender equality will help in bringing up a socially conscious healthy family. Spreading awareness regarding uncontrolled population growth and social evils among young individuals will help in building up a reproductively healthy society. Question 2: Suggest the aspects of reproductive health which need to be given special attention in the present scenario. Answer Reproductive health is the total well being in all aspects of reproduction. The aspects which have to be given special attention in the present scenarios are (1)Counselling and creating awareness among people, especially the youth, about various aspects of reproductive health, such as sexually transmitted diseases, available contraceptive methods, case of pregnant mothers, adolescence, etc. (2)Providing support and facilities such as medical assistance to people during pregnancy, STDs, abortions, contraceptives, infertility, etc. for building a reproductively healthy society Question 3: Is sex education necessary in schools? Why? Answer Yes, introduction of sex education in schools is necessary. It would provide right information to young individuals at the right time about various aspects of reproductive health such as reproductive organs, puberty, and adolescence related changes, safe sexual practices, sexually transmitted diseases, etc. The young individual or adolescents are more susceptible in acquiring various sexually transmitted diseases. Hence, providing information to them at the right time would help them to lead a reproductively healthy life and also protect them from the myths and misconceptions about various sex related issues. Question 4: Do you think that reproductive health in our country has improved in the past 50 years? If yes, mention some such areas of improvement. Answer Yes, the reproductive health has tremendously improved in India in the last 50 years. The areas of improvement are as follows. (1) Massive child immunization programme, which has lead to a decrease in the infant mortality rate (2) Maternal and infant mortality rate, which has been decreased drastically due to better post natal care (3) Family planning, which has motivated people to have smaller families (4) Use of contraceptive, which has resulted in a decrease in the rate of sexually transmitted diseases and unwanted pregnancies Question 5: What are the suggested reasons for population explosion? Answer The human population is increasing day by day, leading to population explosion. It is because of the following two major reasons. (a) Decreased death rate (b) Increased birth rate and longevity The death rate has decreased in the past 50 years. The factor leading to decreased death rate and increased birth rate are control of diseases, awareness and spread of education, improvement in medical facilities, ensured food supply in emergency situation, etc. All this has also resulted in an increase in the longevity of an individual. Question 6: Is the use of contraceptives justified? Give reasons. AnswerYes, the use of contraceptives is absolutely justified. The human population is increasing tremendously. Therefore, to regulate the population growth by regulating reproduction has become a necessary demand in the present times. Various contraceptive devices have been devised to reduce unwanted pregnancies, which help in bringing down the increased birth rate and hence, in checking population explosion. Question 7: Removal of gonads cannot be considered as a contraceptive option. Why? Answer Contraceptive devices are used to prevent unwanted pregnancy and to prevent the spreading of STDs. There are many methods, such as natural, barrier, oral, and surgical methods, that prevent unwanted pregnancy. However, the complete removal of gonads cannot be a contraceptive option because it will lead to infertility and unavailability of certain hormones that are required for normal functioning of accessory reproductive parts. Therefore, only those contraceptive methods can be used that prevent the chances of fertilization rather than making the person infertile forever. Question 8: Amniocentesis for sex determination is banned in our country. Is this ban necessary? Comment. Answer Amniocentesis is a pre-natal diagnostic technique that is used to determine the sex and metabolic disorders of the developing foetus in the mother’s uterus through the observation of the chromosomal patterns. This method was developed so as to determine any kind of genetic disorder present in the foetus. However, unfortunately, this technique is being misused to detect the sex of the child before birth and the female foetus is then aborted. Thus, to prevent the increasing female foeticides, it is necessary to ban the usage of amniocentesis technique for determining the sex of a child. Question 9: Suggest some methods to assist infertile couples to have children. Answer Infertility is the inability of a couple to produce a baby even after unprotected intercourse. It might be due to abnormalities present in either male or female, or might be even both the partners. The techniques used to assist infertile couples to have children are as follows. (a) Test tube babies This involves in-vitro fertilization where the sperms meet the egg outside the body of a female. The zygote, hence produced, is then transferred in the uterus or fallopian tube of a normal female. The babies produced from this method are known as test tube babies. (b) Gamete Intra fallopian transfer (GIFT) It is a technique that involves the transfer of gamete (ovum) from a donor into the fallopian tube of the recipient female who is unable to produce eggs, but has the ability to conceive and can provide right conditions for the development of an embryo. (c) Intra Cytoplasmic sperm injection (ICSI) It is a method of injecting sperm directly into the ovum to form an embryo in laboratory. (d) Artificial insemination Artificial insemination is a method of transferring semen (sperm) from a healthy male donor into the vagina or uterus of the recipient female. It is employed when the male partner is not able to inseminate the female or has low sperm counts. Question 10: What are the measures one has to take to prevent from contracting STDs? Answer Sexually transmitted diseases (STDs) get transferred from one individual to the other through sexual contact. Adolescents and young adults are at the greatest risk of acquiring these sexually transmitted diseases. Hence, creating awareness among the adolescents regarding its after-effects can prevent them from contracting STDs. The use of contraceptives, such as condoms, etc. while intercourse, can prevent the transfer of these diseases. Also, sex with unknown partners or multiple partners should be avoided as they may have such diseases. Specialists should be consulted immediately in case of doubt so as to assure early detection and cure of the disease. Question 11: State True/False with explanation (a) Abortions could happen spontaneously too. (True/False) (b) Infertility is defined as the inability to produce a viable offspring and is always due to abnormalities/defects in the female partner. (True/False) (c) Complete lactation could help as a natural method of contraception. (True/False) (d) Creating awareness about sex related aspects is an effective method to improve reproductive health of the people. (True/False) Answer (a) Abortions could happen spontaneously too. True (b) Infertility is defined as the inability to produce a viable offspring and is always due to abnormalities/defects in the female partner.False Infertility is defined as the inability of the couple to produce baby even after unprotected coitus. It might occur due to abnormalities/defects in either male or female or both. (c) Complete lactation could help as a natural method of contraception. False Complete lactation or lactational amenorrhea is a natural method of contraception. However, it is limited till lactation period, which continues till six months after parturition. (d) Creating awareness about sex related aspects is an effective method to improve reproductive health of the people. True Question 12: Correct the following statements: (a) Surgical methods of contraception prevent gamete formation. (b) All sexually transmitted diseases are completely curable. (c) Oral pills are very popular contraceptives among the rural women. (d) In E. T. techniques, embryos are always transferred into the uterus. Answer (a) Surgical methods of contraception prevent gamete formation.Correction Surgical methods of contraception prevent the flow of gamete during intercourse. (b) All sexually transmitted diseases are completely curable. Correction Some of the sexually transmitted diseases are curable if they are detected early and treated properly. AIDS is still an incurable disease. (c) Oral pills are very popular contraceptives among the rural women.Correction Oral pills are very popular contraceptives among urban women. (d) In E. T. techniques, embryos are always transferred into the uterus. Correction In embryo transfer technique, 8 celled embryos are transferred into the fallopian tube while more than 8 celled embryos are transferred into the uterus. \|« Previous\|\|Next »\| NCERT Solutions for Class 12 Biology All Chapters - Chapter 1 – Reproduction in Organisms - Chapter 2 – Sexual Reproduction in Flowering Plants - Chapter 3 – Human Reproduction - Chapter 4 – Reproductive Health - Chapter 5 – Principles of Inheritance and Variation - Chapter 6 – Molecular Basis of Inheritance - Chapter 7 – Evolution - Chapter 8 – Human Health and Disease - Chapter 9 – Strategies for Enhancement in Food Production - Chapter 10 – Microbes in Human Welfare - Chapter 12 – Biotechnology and its Applications - Chapter 13 – Organisms and Populations - Chapter 14 – Ecosystem - Chapter 15 – Biodiversity and Conservation - Chapter 16 – Environmental Issues NCERT Solutions Subject wiseWe are giving the subjectwise solution of NCERT Class 12 books. They will find chapter wise solutions for each subject which can be downloaded. - NCERT Solutions for Class 12 Physics - NCERT Solutions for Class 12 Chemistry - NCERT Solutions for Class 12 Biology - NCERT Solutions for Class 12 Maths - NCERT Solutions for Class 12 Accountancy - NCERT Solutions for Class 12 Business Studies - NCERT Solutions for Class 12 Geography - NCERT Solutions for Class 12 History - NCERT Solutions for Class 12 Political Science - NCERT Solutions for Class 12 Physiology - NCERT Solutions for Class 12 Sociology - NCERT Solutions for Class 12 Economics - NCERT Solutions for Class 12 English - NCERT Solutions for Class 12 Hindi All NCERT SolutionsYou can also check out NCERT Solutions of other classes here. Click on the class number below to go to relevant NCERT Solutions of Class 1, 2, 3, 4, 5, 6, 7, 9, 9, 10, 11, 12. To get fastest exam alerts and government job alerts in India, join our Telegram channel.

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