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What’s behind a food’s flavor? More than what we taste, it turns out. People often use the terms taste and flavor interchangeably. Scientists do not. Flavor is a complicated mix of sensory data. Taste is just one of the senses that contributes to flavor. Here’s how it works: As you chew, your food releases molecules that begin to dissolve in your saliva. While still in the mouth, these food molecules contact bumpy papillae (Puh-PIL-ay) on your tongue. These bumps are covered with taste buds. Openings in those taste buds, called pores, allow the tasty molecules to enter. Once inside the taste pores, those chemicals make their way to specialized cells. These cells sense tastes. Taste cells have features on the outside known as receptors. Different chemicals fit into different receptors, almost like a key into a lock. The human tongue has 25 different types of receptors to identify various chemicals that are bitter. Just a single receptor type unlocks the sense of sweetness. But that sweet receptor “has many pockets, like one of those toys that has slots you can fit a square or triangular block into,” explains Danielle Reed. She’s a geneticist at the Monell Chemical Senses Center in Philadelphia, Pa. Each of those slots, she explains, responds to a different type of sweet molecule. For example, some respond to natural sugars. Others respond to artificial sweeteners. But those tastes sensed by the tongue are only a part of what we experience as flavor. Think about biting down on a just-picked peach. It feels soft and warm from the sun. As its juices flow, they release odor molecules that you smell. These odors mingle with the fruit’s taste and that soft, warm feel. Together, they give you the complex sense of a sweet peach — and let you tell the difference between it and a sweet blueberry. (Or between a bitter Brussels sprout and a bitter turnip.) Flavor, then, is that complex assessment of a food or beverage that develops when our brain melds together data from our different senses. Taste and flavor together influence how people experience food. Why do we need both? “Taste is a nutrient detector and a toxin avoider” that we’re born with, explains Dana Small. She’s a clinical psychologist at Yale University in New Haven, Conn. Sweet or fatty foods are calorie rich. Those are welcoming tastes when someone is hungry. Bitter warns that some food may be poisonous. From birth, she explains, the body is wired to recognize such taste-based messages.
In this video, educator Angela Schipper demonstrates how to build a model of an aquifer – a layer of rock or other material that carries water underground. This is an excellent activity that needs only a few easy to organise resources. Point of interest Teachers may want to ask students why the water does not simply disappear in the ground. (Not all rock layers in the ground are equally porous – some are impermeable). Nature of Science Scientists make use of models to test predictions. Models allow scientists to test a range of scenarios. without potentially harming the environment. We know when rain falls on hard surfaces, it gathers in puddles and eventually evaporates. But what happens to water that pours onto a garden or a paddock? We are going to make an aquifer model to see the part of the water cycle that happens beneath our feet. These are the materials we will need to set it up. An aquifer is a layer of rock or other material that carries water underground. Real aquifers are made of geological materials like sand, pumice or fractured rock. We are going to use aquarium stones. We will slope the stones because we want to have a lake at one end of our model. We can’t see aquifers because they are beneath the surface, so we will add a layer of soil, pat the soil down a bit because we don’t want too much erosion, then we will place a layer of grass clippings on to represent vegetation. Now, let’s make it rain. Use a cup with holes punched in the bottom so it provides a gentle flow. Watch what happens to the coloured water as it hits the soil. Some of it runs off on the surface into the lake right away. Some of the rain moves down through the soil and begins to fill up the aquifer. We can see a lake is forming in the depression we made. The lake is fed directly by rain through run-off and also by water moving through the aquifer. The top of the saturated layer of our model is called the water table. The water table fluctuates depending upon how much water enters into or is discharged from the aquifer. Groundwater is used extensively for drinking water and irrigation. To obtain the water, we need to drill a well deep enough to penetrate the water table. Use a spray pump to represent a bore or municipal well. Dr Ravi Gooneratne, Lincoln University
Leadership & Human Behavior As a leader, you need to interact with your followers, peers, seniors, and others; whose support you need in order to accomplish your goals. To gain their support, you must be able to understand and motivate them. To understand and motivate people, you must know human nature. Human nature is the common qualities of all human beings. People behave according to certain principles of human nature. Human needs are an important part of human nature. Values, beliefs, and customs differ from country to country and even within group to group, but in general, all people have a few basic needs. As a leader you must understand these needs because they can be powerful motivators. Unlike others researchers of his time, Abraham Maslow's based his theory of human needs on creative people who used all their talents, potential, and capabilities (Bootzin, Loftus, Zajonc, Hall, 1983). His methodology differed from other psychological researchers who mostly observed mentally unhealthy people. Maslow (1943) felt that human needs were arranged in a hierarchical order that could be divided into two major groups: basic needs and metaneeds (higher order needs): - Basic Needs are physiological, such as food, water, and sleep; and psychological, such as affection, security, and self-esteem. These basic needs are also called “deficiency needs” because if they are not met by an individual, then that person will strive to make up the deficiency. - Metaneeds or being needs (growth needs). These include justice, goodness, beauty, order, unity, etc. Basic needs normally take priority over these meta needs. For example, a person who lacks food or water will normally not attend much to justice or beauty needs. These needs are often listed in a hierarchical order in the form of a pyramid to show that the basic needs (bottom ones) must be met before the higher order needs (however, it should be pictured more as a box, see the section, Criticisms and Strengths, below for more information): - Self-actualization — know exactly who you are, where you are going, and what you want to accomplish. A state of well-being - Esteem — feeling of moving up in world, recognition, few doubts about self - Belongingness and love — belong to a group, close friends to confide with - Safety — feel free from immediate danger - Physiological — food, water, shelter, sex Note: Maslow later added more higher order needs to his theory. Maslow posited that people want and are forever striving to meet various goals. Because the lower level needs are more immediate and urgent, then they come into play as the source and direction of a person's goal if they are not satisfied. A need higher in the hierarchy will become a motive of behavior as long as the needs below it have been satisfied. Unsatisfied lower needs will normally dominate unsatisfied higher, thus they must normally be satisfied before the person can rise up in the hierarchy. Knowing where a person is located on the pyramid will aid you in determining effective motivators. For example, motivating a middle-class person who has met the first four levels with positive feedback and encourage, such as a certificate, will have a greater impact than using the same motivator to affect a minimum wage person from the ghetto who is desperately struggling to meet the first couple of needs. It should be noted that almost no one stays in one particular hierarchy for an extended period. We constantly strive to move up, while at the same time various forces outside our control try to push us down. Those on top get pushed down for short time periods, e.g., death of a loved-one or an idea that does not work; while those on the bottom get pushed up, e.g., earn the education they need or come across a small prize. Our goal as leaders therefore is to help people obtain the skills, knowledge, and benefits that will push them up the hierarchy. People who have their basic needs met become much better workers as they are able to concentrate on fulfilling their and the organization's visions, rather than consistently struggling to make ends meet. The above statements may be considered generalizations. Maslow's theory has often been criticized because we can find exceptions to it, such as the military, police, firefighters, etc. who will risk their safety for the well-being of others or parents who will sacrifice their basic needs for their children. However, there are very few theories about human nature that are not flawed once we start drilling down to the individualistic level. Even Newton's theory of physics, which became laws, fell apart once we were able to drill down to the atomic level. A recent study (Tay, Diener, 2011) discovered that as hypothesized by Maslow, people tend to achieve basic and safety needs before other needs. However, fulfilling the various needs has relatively independent affects on a person's Subjective Well-Being. Thus, rather than being a pyramid with the basic human needs arranged in a hierarchical order, it is more like a box with the basic human needs scattered within and depending on the situation and/or environment, different needs rise to the top to compensate for the deficient needs. Maslow's theory remains a classic because rather than looking at psychology as strictly the study of the mentally ill, his theory was based upon mentally healthy people. And being one of the first humanistic ones, it has its share of flaws. In Maslow's (1971) later years, he become more interested in the higher order or metaneeds and tried to further distinguish them. Maslow theorized that the ultimate goal of life is self-actualization, which is almost never fully attained but rather is something we try to always strive for. He later theorized that this level does not stop; it goes on to self-transcendence, which carries us to the spiritual level, e.g. Gandhi, Mother Theresa, Dalai Lama, or even poets, such as Robert Frost. Maslow's self-transcendence level recognizes the human need for ethics, creativity, compassion and spirituality. Without this spiritual or transegoic sense, we are simply become machines. This expansion of the higher order needs is shown here: Note that the four meta needs (above the inner pyramid) can be pursued in any order, depending upon a person's wants or circumstances, as long as the basic needs have all been met: - 8. Self-transcendence — a transegoic (see Note below) level that emphasizes visionary intuition, altruism, and unity consciousness. - 7. Self-actualization — know exactly who you are, where you are going, and what you want to accomplish. A state of well-being. - 6. Aesthetic — to do things not simply for the outcome but because it's the reason you are here on earth — at peace, more curious about the inner workings of all things. - 5. Cognitive — to be free of the good opinion of others — learning for learning alone, contribute knowledge. - 4. Esteem — feeling of moving up in world, recognition, few doubts about self. - 3. Belongingness and love — belong to a group, close friends to confide with. - 2. Safety — feel free from immediate danger. - 1. Physiological — food, water, shelter, sex. Note: Transegoic means a higher, psychic, or spiritual state of development. The trans is related to transcendence, while the ego is based on Freud's work. We go from preEGOic levels to EGOic levels to transEGOic. The EGO in all three terms is used in the Jungian sense of consciousness as opposed to the unconscious. Ego equates with the personality. In addition, just as in his earlier model, we may be in a state of flux — we shift between levels (Maslow, 1968). For example there may be peak experiences for temporary self-actualization and self-transcendence. These are our spiritual or creative moments. Characteristics of Self-actualized People People who have reached the state of self-actualization normally display the following characteristics: - have better perceptions of reality and are comfortable with it - accept themselves and their own natures - lack artificiality - focus on problems outside themselves and are concerned with basic issues and eternal questions - like privacy and tend to be detached - rely on their own development and continued growth - appreciate the basic pleasures of life (e.g. do not take blessings for granted) - have a deep feeling of kinship with others - are deeply democratic and are not really aware of differences - have strong ethical and moral standards - are original, inventive, less constricted and fresher than others Going Beyond Maslow While the research of Maslow's theory has undergone limited empirical scrutiny, it still remains quite popular due to its simplicity and being the start of the movement away from a totally behaviorist/reductionistic/mechanistic approach to a more humanistic one. In addition, a lot of concerns are directed at his methodology in that he picked a small number of people that he declared self-actualized and came to the conclusion about self-actualization. However, he understood this and thought of his work as simply a method of pointing the way, rather than being the final say. In addition, he hoped that others would take up the cause and complete what he had begun. Other researchers have taken up his cause and furthered refined them, mostly in the area of organizations and work. Herzberg, Alderfer, and McGregor's research are all closely tied to Maslow's theory. Frederick Herzberg was considered one of the most influential management consultants and professors of the modern postwar era. Herzberg was probably best known for his challenging thinking on work and motivation. He was considered both an icon and legend among visionaries such as Abraham Maslow, Peter Drucker, and Douglas McGregor. Herzberg (1966) is best known for his list of factors that are based on Maslow's Hierarchy of Needs, except his version is more closely related to the working environment: HERZBERG'S HYGIENE & MOTIVATIONAL FACTORS Hygiene factors must be present in the job before motivators can be used to stimulate a person. That is, you cannot use motivators until all the hygiene factors are met. If the factor is not met, then it becomes a Dissatisfier. Herzberg's needs are specifically job related and reflect some of the distinct things that people want from their work, as opposed to Maslow's Hierarchy of Needs that reflect the needs in a person's life. Hygiene or Dissatisfiers: - Working conditions - Policies and administrative practices - Salary and Benefits - Job security - Personal life Motivators or Satisfiers: - Job challenge Hygiene or dissatisfiers factors must be present in the job before motivators can be used to stimulate a person. That is, you cannot use motivators until all the hygiene factors are met. Herzberg's needs are specifically job related and reflect some of the distinct things that people want from their work as opposed to Maslow's Hierarchy of Needs that reflect all the needs in a person's life. Building on this model, Herzberg coined the term job enrichment — the process of redesigning work in order to build in motivators by increasing both the variety of tasks that an employee performs and the control over those tasks. It is associated with the design of jobs and is an extension of job enlargement (an increase in the number of tasks that an employee performs). Note the term Job Enlargement means that a variety of tasks are performed to reduce boredom, rather than overloading a person with too many tasks. Douglas McGregor (1957) developed a philosophical view of humankind with his Theory X and Theory Y — two opposing perceptions about how people view human behavior at work and organizational life. McGregor felt that organizations and their managers followed one or the other approach: - People have an inherent dislike for work and will avoid it whenever possible. - People must be coerced, controlled, directed, or threatened with punishment in order to get them to achieve the organizational objectives. - People prefer to be directed, do not want responsibility, and have little or no ambition. - People seek security above all else. In an organization with Theory X assumptions, management's role is to coerce and control employees. - Work is as natural as play and rest. - People will exercise self-direction if they are committed to the objectives (they are NOT lazy). - Commitment to objectives is a function of the rewards associated with their achievement. - People learn to accept and seek responsibility. - Creativity, ingenuity, and imagination are widely distributed among the population. People are capable of using these abilities to solve an organizational problem. - People have potential. In an organization with Theory Y assumptions, management's role is to develop the potential in employees and help them to release that potential towards common goals. Theory X is the view that traditional management has taken towards the workforce. Most organizations are now taking the enlightened view of theory Y (even though they might not be very good at it). A boss can be viewed as taking the theory X approach, while a leader takes the theory Y approach. Notice that Maslow, Herzberg, and McGregor's theories all tie together: - Herzberg's theory is a micro version of Maslow's theory that is focused in the work environment. - McGregor's Theory X is based on workers caught in the lower levels (1 to 3) of Maslow's theory due to bad management practices, while his Theory Y is for workers who have gone above level 3 with the help of management. - McGregor's Theory X is also based on workers caught in Herzberg's Hygiene Dissatisfiers, while Theory Y is based on workers who are in the Motivators or Satisfiers section. Go to Page 2 of Leadership and Human Behavior (Alderfer and Vroom) Go to the main Leadership Page Alderfer, C. (1969). An Empirical Test of a New Theory of Human Needs. Organizational Behavior and Human Performance, vol. 4, pp. 142 - 175. Bootzin, R., Loftus, E., Zajonc, R., Hall, E. (1983). Psychology Today: An Introduction. New York: Random House. Fifth Edition. Herzberg, F. (1966). Work and the Nature of Man. Cleveland: World Publishing Co. Maslow, A.H. (1943). A Theory of Human Motivation. Psychological Review, 50, 370-396. Maslow, A.H. (1968). Toward a Psychology of Being. (2nd ed.). New York: Van Nostrand Reinhold. Maslow, A.H. (1971). The Farther Reaches of Human Nature. New York: McGraw-Hill. McGregor, D. (1957). Proceedings of the Fifth Anniversary Convocation of the School of Industrial Management, The Human Side of Enterprise. Massachusetts Institute of Technology. Tay, L., Diener, E. (2011). Needs and subjective well-being around the world. Journal of Personality and Social Psychology, Vol 101(2), Aug 2011, 354-365. Vroom, V. (1964). Work and Motivation. New York: Jon Wiley & Sons.
Cleft lip and cleft palate are two common but markedly different birth defects that affect about one in every 700 newborns. These developmental deformities occur in the first trimester of a woman’s pregnancy - cleft lip in week seven and cleft palate in week nine. Cleft lip and cleft palate occur simultaneously in about half of all cases and separately in approximately a quarter of all cases. A cleft lip is essentially a separation of the two sides of the lip. In many cases, this separation will include the bone and gum of the upper jaw. A cleft palate occurs when the sides of the palate fail to “fuse” as the fetus is developing, which results in an opening in the roof of the mouth. The cleft deformities are categorized according to their location in the mouth and the size of the defect. Unilateral Incomplete: A cleft on only one side of the mouth that does not extend as far as the nostril. Unilateral Complete: A cleft on only one side of the mouth that extends into the corresponding nostril. Bilateral Complete: Larger clefts affecting both sides of the mouth which each extend as far as the nostril. Microform Cleft: A mild case of cleft lip which may simply form a bump on the lip, or a small scar line extending toward the nostril. Reasons for cleft lip and cleft palate correction Cleft lip and cleft palate are highly treatable deformities, though it may take a whole team of different specialists to fully treat the condition. The prognosis for sufferers who receive corrective treatment is excellent: medically, physically, dentally, and emotionally. There are however, a series of risks for those who do not receive corrective treatment: Speech – Children born with cleft deformity are likely to experience speech problems unless treatment is sought. Speech problems are detrimental to a child’s social and emotional development. Feeding – Babies with a cleft palate or a complete cleft lip have problems drinking milk. The gap means that liquids can pass from the mouth to the nasal cavity. This can be dangerous unless the child is fed sitting upright. Hearing Loss & Frequent Ear Infections – A cleft palate can cause the eustachian tubes (connecting the throat to the ear) to be incorrectly positioned. The fluid build up which results from this poor positioning can lead to painful middle ear infections. Severe and prolonged ear infections can lead to complete hearing loss. Dental Issues – Abnormalities in the upper jaw, gum, or arch can cause teeth to become impacted (unable to erupt) or absent completely. The shape of the mouth might not permit proper brushing which can lead to periodontal disease and tooth decay. What does cleft lip and cleft palate treatment involve? Initially, surgeons will work to close the cleft openings in the first six months of the child’s life. Unfortunately, this does not cure the dental problems that occur as a result of cleft lip and cleft palate defects. The dentist will perform a thorough examination of the teeth surrounding the deformity. Panoramic x-rays will generally be taken to allow the dentist to determine the best course of treatment. The dentist may implant teeth to fill resulting gaps, and/or place braces on the teeth in order to correctly align the upper arch. These treatments will restore functionality to the jaw and improve the aesthetic appearance of the smile. Dental restoration work can generally be performed under local anesthetic and will not require an overnight stay. If your child was born with any cleft deformity, we strongly encourage you to contact our office to schedule a consultation.
Accuracy and Uncertainty in Climate Models Global climate models are used to predict what will happen to Earth’s climate in the future. Groups like the Intergovernmental Panel on Climate Change (the IPCC) compare the results from several different climate models as they figure out what is most likely to happen. But how do scientists know whether a model’s predictions are correct? How do they figure out whether the model is doing a good job at predicting the future of climate change? To figure out whether a climate model is doing a good job, scientists give it a test. The model is run through a time period for which we have actual measurements of Earth’s climate, the past 100 years for example. The results from the model are compared with the actual measurements of real climate. If the model and the actual measurements are similar, then the math equations in the model that are used to describe how Earth works are probably quite accurate. If the model results are very different from our records of what actually happened, then the model needs some work. Some uncertainty about our future climate is because there are processes and feedbacks between different parts of the Earth that are not fully understood. These are difficult to include in the models until we understand them better. Today, scientists are conducting research to learn more about how some of the less well-known processes and feedbacks work. For example, the effects of clouds on climate is known to be a large, however it is not fully understood and so scientists are researching clouds to ensure that climate models are as accurate as possible. Scientists work to ensure that natural processes are represented in climate models as accurately as possible, so that models can be used to make predictions of future climate that are as accurate as possible. Most of the uncertainty in these predictions of future climate is not related to natural processes. Instead, it is uncertain how much pollution humans will be adding to the atmosphere in the future. Innovations that stop or limit the amount of greenhouses gases that are produced, laws and rules that change the amount of pollutants that are released, and how the growing human population lives in the future are all somewhat unknown. To deal with this, climate models are often run several times, each time with different amounts of pollution and development by humans. According to the IPCC, most climate scientists agree that while climate models are not perfect, they are currently pretty good and better models would not change the conclusion that Earth’s average temperature is warming..
Political ChangesThe aforementioned Stephen Douglas's strong interest in a transcontinental railroad led him to introduce in Congress a fateful legislative act that finally destroyed the Compromise of 1850. (This was a bill that, among other things, proposed a new and more effective fugitive slave law; that the slave trade, but not slavery itself be abolished in the District of Columbia; and that in the rest of the lands acquired from Mexico, territorial governments be formed without restrictions on slavery.) As a senator from Illinois, a resident of Chicago, and the acknowledged leader of Northwestern Democrats, Douglas obviously wanted the transcontinental railroad for his own city and section. But he was aware of the strength of the main argument against the Northern route: that west of the Mississippi it would run mostly through country largely inhabited by Indians. As a result, he introduced a bill in January 1854 to organize (and thus open to white settlement) a huge new territory, known as Nebraska, west of Iowa and Missouri. Douglas knew the South would oppose his bill because it would lead the way for a new free state; the proposed territory was in the area of the Louisiana Purchase north of the Missouri Compromise line and thus closed to slavery. In an effort to make the measure acceptable to Southerners, Douglas added a provision that the status of slavery in the territory would be determined by the territorial legislature - that is, according to popular sovereignty. This meant that the region could choose to open itself to slavery, but few believed it actually would. When Southern Democrats demanded more, Douglas agreed to two changes in the bill. He wrote an additional clause explicitly withdrawing the antislavery provision of the Missouri Compromise (which the popular sovereignty provision of his original bill had done implicitly), and an adjustment creating two territories, Nebraska and Kansas, instead of one, hence establishing a new territory (Kansas) that might become a slave state. In its final form the measure was known as the Kansas-Nebraska Act. President Pierce supported the bill; and after a strenuous debate, it became law in May 1854 with the unanimous support of the South and the partial support of the Northern Democrats. This piece of legislation produced many immediate, far-reaching changes. It destroyed the Whig party, which disappeared almost entirely by 1856. It divided the Northern Democrats (many of whom were shocked by the repeal of the Missouri Compromise, which to them was an almost sacred part of the fabric of the Union) and drove many of them from the party. Most important of all, it encouraged the creation of a new party that was openly sectional in its composition and beliefs. People in both major parties who opposed Douglas's bill began to call themselves Anti-Nebraska Democrats and Anti-Nebraska Whigs. In 1854, they formed a new organization and named it the Republican party. In the elections of that year, the republicans won enough seats in Congress to be able to organize the House of Representatives and won control of several Northern state governments.
Printable ESL Word Search Puzzles for Kids, Word Puzzles for Teaching Kids, Vocabulary Word Search Puzzles for Beginners, Worksheets for ESL Kids, Children's Puzzles, Worksheets, Word Search with Answer Sheets, Free ESL Puzzles This area features many phonics printable activities from our Kiz Phonics® course. The phonics worksheets will help teach short & long vowels, consonant blends and digraphs, vowel digraphs, r-controlled vowels and other phonemes, which are essential for teaching early literacy. This section features many phonics games and videos to help children with no reading skills learn to decode and read words in English. Our videos teach the different phonemes without any ambiguity and the games help children pratice themselves. The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.
LEXINGTON, Ky. − A team of researchers led by University of Kentucky College of Agriculture Professor Joe Chappell is making a connection from prehistoric times to the present that could result in being able to genetically create a replacement for oil and coal shale deposits. This could have fundamental implications for the future of the earth’s energy supply. Tom Niehaus, completing his doctorate in the Chappell laboratory; Shigeru Okada, a sabbatical professor from the aquatic biosciences department at the University of Tokyo; Tim Devarenne, a UK graduate and now professor of biochemistry and biophysics at Texas A&M University; and UK colleagues, Chappell, David Watt, professor of cellular and molecular biochemistry (College of Medicine) and his post-doctoral associate Vitaliy Sviripa had an important paper published today in the Proceedings of the National Academy of Sciences (PNAS). Their research findings go well beyond the basic science dealing with the origins of oil and coal. While scientists previously established that oil and coal have their roots in the organisms that lived on the planet over 500 million years ago, researchers only are sure of one organism that directly contributed to these natural resources. That organism is the algae Botryococcus braunii which left behind its chemical fingerprints – an oil that over geological time has turned into oil and coal shale deposits. “Even more exciting is that this unique algae, B. braunii, still exists today and has been the target of studies from the large chemical and petrochemical industries,” said Chappell. This algae is very slow growing, so it is not necessarily a good source for biofuels. However, if scientists can capture its genetic blueprints for the biosynthesis of these high value oils, then these genes could be used to generate alternative production platforms. This team of investigators isolated the necessary genes, characterized the biochemical traits encoded by these genes, and then genetically engineered yeast to produce this very high-value oil. This work has provided the first example of recreating a true direct replacement for oil and coal shale deposits. Chappell said, “This represents the culmination of an outstanding effort to understand a fundamental process that has direct ramifications for a real-world problem — how are we going to generate a truly renewable biofuel supply?” Devarenne added, “This study identifies a very remarkable molecular mechanism for the production of hydrocarbons that, as far as we can tell, is not found in any other organism. Thus, it offers a unique insight into how hydrocarbons were produced hundreds of millions of years ago.”
An oxide is a chemical compound consisting of molecules in which at least one oxygen atom is bonded to other elements. Most of the Earth's crust consists of oxides. Many oxides are produced when elements react with oxygen in the air. Several materials that are considered "pure elements" have an oxide coating. For example, aluminum foil has a thin skin of aluminum oxide (alumina, Al2O3) that protects the foil from further corrosion. The two principal oxides of carbon, carbon monoxide and carbon dioxide, are produced by the combustion of hydrocarbons. Water (H2O) may be considered an oxide of hydrogen. In the eighteenth century, oxides were named calxes or calces, after the calcination process used to produce oxides. Calx was later replaced by oxyd. The name of an oxide is often based on the number of oxygen atoms in each molecule of the oxide. For example, an oxide containing only one oxygen atom per molecule is called an oxide or monoxide; an oxide containing two oxygen atoms per molecule is a dioxide; three oxygen atoms, trioxide; four oxygen atoms, tetroxide; and so on, following the Greek numerical prefixes. Two other types of oxide are: In such species, oxygen is assigned oxidation states higher than that of oxide (which is 2-). Oxides of more electropositive elements (particularly metals) tend to be basic, and they are called basic anhydrides. Upon adding water, they may form basic hydroxides. For example, sodium oxide is basic; when hydrated, it forms sodium hydroxide. Conversely, oxides of more electronegative elements tend to be acidic. They are called acid anhydrides. Upon adding water, they form oxoacids. For example, dichlorine heptoxide is an acidic oxide; perchloric acid is a hydrated form. In some cases, an oxide can behave as an acid or a base, under different conditions. They are called amphoteric oxides. An example is aluminum oxide. Other oxides do not behave as either acid or base. The oxide anion (O2−) is the conjugate base of the hydroxide ion (OH−) and is encountered in an ionic solid such as calcium oxide. The O2− anion is unstable in aqueous solution—its affinity for H+ is so great (pKb ~ -22) that it extracts a proton from a solvent H2O molecule: The oxides of chemical elements in their highest oxidation state are predictable and their chemical formulas can be derived from the number of valence electrons in the atoms of those elements. One exception is copper, for which the highest oxidation state oxide is copper(II) oxide and not copper(I) oxide. Another exception is fluoride that does not exist as expected as F2O7 but as OF2, with the least electronegative element given priority.. Phosphorus pentoxide, the third exception, is properly represented by the chemical formula P4O10, not P2O5. Although many anions are stable in aqueous solution, ionic oxides are not. For example, sodium chloride dissolves readily in water to give a solution containing Na+ and Cl- ions. Oxides do not behave like this. When an ionic oxide dissolves, each O2− ion become protonated to form a hydroxide ion. Although calcium oxide (CaO) is said to "dissolve" in water, the products include hydroxide ions: Concentrations of oxide ions in water are too low to be detectable with current technology. Authentic soluble oxides do exist, but they release oxyanions, not O2-. Well-known soluble salts of oxyanions include sodium sulfate (Na2SO4), potassium permanganate (KMnO4), and sodium nitrate (NaNO3). New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here: The history of this article since it was imported to New World Encyclopedia:
Referencing: you know you have to do it, but it's a real chore. We will try to demystify the process and help you to feel more confident about referencing. We're going 'back to basics', so if you're confident about referencing, skip this bit. Let's start with some definitions: Appears in the text and alerts your readers to a reference; for example, (Smith and Jones 1997 ), or Bloggs (2003), or Tiger and Fox . Citations often take the form of surnames and dates, or numbers. A record of all the information your readers will need to find the source for themselves; for example: Smith, A. (2003). Referencing is your friend. Oxford. Oxford University Press. A full list of all the references you have used to research and write your assignment. Can include sources that are not referenced in the text. A full list of the references that are cited in your text. Should not include anything that is not cited. Referencing can be stressful because, as you are probably aware, universities take a very Dim View of plagiarism. Trying to pass off the work of others as your own can lead to a mark of zero or, in extreme cases, lead to you being thrown out of university. Apart from the obvious reason that if you're caught you'll be in big trouble, why worry about referencing? You may be thinking “won't it look more impressive if they think I came up with these ideas?”, but always remember, your tutors are not silly (generally); they are experts in their fields and will know what's been written and who wrote it. You are very unlikely to 'pull the wool over their eyes', so don't try. It's also very bad manners to try to pass-off someone else's ideas as your own. Referencing is considered important at university because the academic style of writing requires you to respond to the ideas and writing of other people. The skill lies in how well you can understand and respond to other people's work. Referencing your source material also allows your readers to find your sources and read them for themselves, which is very important in the academic world. Whenever you use someone else's ideas in your text. Even if you have just used someone's work to guide what you have written, you still need to acknowledge this in your references. Obviously direct quotations need to be referenced. Changing the wording of your source doesn't prevent you from having to reference: paraphrased or summarised sources still need referencing. Statistics, facts, examples from other people's work, diagrams, images and photographs all need referencing too. Plagiarism is passing off other people's work as your own: it is intellectual theft. Plagiarism can be obvious: 'cutting and pasting' work, copying word-for-word, or buying an essay written by someone else, or it can be more subtle: using someone else's ideas without acknowledging where they came from. Both forms of plagiarism are equally serious. You're right to take plagiarism seriously, you can bet your university will. But don't worry, there are ways you can ensure that you are not plagiarising. Follow the tips below and relax. Warning! Ignorance is no defence: accidental plagiarism is still a punishable offence. The business of referencing can be confusing, but there are a few things that are fairly straightforward to remember. If you can master the basics, you can check more complex issues with your tutor or a librarian. Try the referencing quiz to see how much you know about referencing. It will help to remind you of the basics. 1. Read through the list of statements about referencing in the table below. 1.Decide whether each statement is true or false. \|Information on the internet is 'free'. Anyone can use it without having to reference it.\| \|As long as I use speech marks, I don't have to say where the quotation is from.\| \|I can copy pictures/diagrams/photos without referencing them.\| \|If I summarise other people's ideas, I still need to reference them.\| \|If I paraphrase or rewrite the information, I don't need to reference it.\| \|Some information is 'common knowledge', so it doesn't need to be referenced.\| \|I must never reference work I have not read.\| \|Statistics don't need to be referenced.\| \|If I cite someone once, I can use their ideas later without needing to cite them again.\| \|Plagiarism is copying published work; I can copy my mate's work because it's not been published.\| When you've made your decisions, click below to reveal the answers. Now you should have a better idea of when and where you need to reference. The next few pages will help you perfect your referencing technique
All will be well with your child's recognition of sight words when she completes this page on the word "all"! Learning the sight word "on" is an important step to reading fluency. This worksheet will help kids practice by tracing, writing and coloring the word. Looking for a fun way to give your child some writing practice? On this worksheet, he'll get to trace and write the word "many." This worksheet practices spelling, handwriting, and reading comprehension skills by asking kids to trace and write the word "two." The best way to learn new words is to practice them in context, and this worksheet allows kids to use the word "live" in a sentence. This 'Write and Draw Sight Words' worksheet is all about the word 'girl': have your child trace the word first, then try writing it on her own. This worksheet builds reading and writing skills, and shows kids that reading can be fun! Kids practice tracing the word "fly", then write it in a sentence. This worksheet makes learning sight words a hands-on activity as your child traces the word "cold" then practices writing it himself. This 'Write and Draw Sight Words' worksheet, all about the word 'eat', will have kids writing, reading and spelling in a jif. This fun worksheet, all about the word "grow," is chock-full of fine motor skills practice, including tracing, writing, and even a coloring activity, too! Ease your child into learning simple, everyday sight words with this worksheet on the word 'four'. In this worksheet, your child will practice tracing the word "white," and then write it on her own in a sentence, helping to build strong reading skills. Learning sight words doesn't have to be boring. This worksheet adds in a fun drawing activity to get kids excited about learning to spell the word "six." Your Kindergartener will have a blast learning short, everyday sight words with these colorful worksheets. Heat up your child's sight word learning with this worksheet, featuring the word "hot." By tracing and then writing the sight words on their own, your preschooler will practice penmanship and broaden his vocabulary at the same time. What letters is the word "made" made up of? Find out on this great writing worksheet. If you want to give your child great phonics practice, you could always give her this great worksheet, featuring the word "always." By completing this sheet, preschoolers will practice their handwriting and build their budding vocabulary. Learning how to read and write numbers is an important building block. This worksheet focuses on reading and writing the word "eight." Practice writing and spelling with this worksheet featuring the sight word "under." Help your kids enjoy writing with this fun, sight word worksheet. Not only do kids trace and write the word "sleep," they also get to draw a picture, too. On this sight word worksheet, kids write and trace the word "green," then break out that green crayon and do some coloring, too. In this early reading and writing worksheet, your child will be asked to trace the word "hold", and then try writing it on her own in a sentence. After tracing and writing the word "walk" on this worksheet, your child will use his imagination to draw a picture about the featured word. As your child completes this sight word worksheet, featuring the word "three," she'll get practice with writing, drawing, and counting, too! Help your child learn the sight word "it" with this printable kindergarten phonics worksheet. Help your kid learn the sight word "is" by tracing the letters and writing the word in a sentence. He'll learn how to read and write "is" with this worksheet.
In Part 1 a first, simple model of planetary temperature was discussed, all based on knowledge of how much starlight a planet receives () and how “reflective” that planet is (i.e, its albedo, , an effect elaborated on in this post). In the first post, an “effective temperature” was solved for of the form: where is a geometrical redistribution term that accounts for how well the input of stellar energy is evened out across the planet by rotation/thermal inertia and planetary motions. For a sufficiently rotating planet with an advecting atmosphere, it takes the value of ~4, but it would be more appropriate to take on a different local value on an airless body incapable of transporting much heat around (concerning the question of habitability, this could set up a regime in which water could exist in liquid form over parts of a planet but not others). We now introduce the effect of an atmosphere that can interact with the radiation entering or exiting the planet. On Earth, that interaction is predominately in the infrared (the outgoing energy) via absorption/emission processes and is accounted for by trace gases in the atmosphere, which we refer to as greenhouse gases (water vapor, carbon dioxide, methane, nitrous oxide, etc); the interaction can also occur with aerosol particles in the atmosphere and with clouds, though these latter two also tend to scatter shortwave solar energy and cause a net cooling effect on Earth (there are exceptions to this, such as black carbon). Ozone interacts in the infrared as a greenhouse gas, but also absorbs incoming UV radiation high in the stratosphere to set up a persistent thermal inversion where temperatures increase with height. On Venus, the predominant atmospheric constituent is CO2 which acts as a strong greenhouse agent, although contributions exist from sulfur dioxide, water vapor, and sulfuric acid based clouds. On Titan, one of Saturn’s moons, a greenhouse effect is arises due to N2, CH4, and H2. It is a widespread notion that symmetric, diatomic molecules cannot behave as greenhouse gases (as is the case with both main constituents of the Earth’s atmosphere- N2 and O2). In order to be a good infrared absorber, the molecule must 1) have quantum energy transitions whose energy corresponds to the infrared spectrum 2) a dipole moment, or a charge distribution such that a disproportionate amount of the electron clouds “negative charge” is clumped up to one side and the “positive charge” to another side. Symmetric, diatomic molecules do not exhibit a static electric dipole moment (as with water vapor) nor is there the possibility to vibrationally induce a temporary dipole moment, as in the case of CO2, where the “bending” mode allows for interaction of thermal radiation at ~15 micron wavelength. However, in sufficiently dense atmospheres (as on Titan and on gas giant planets) collision-induced absorption leads to absorption features in diatomic gases. The collision-induced dipole that forms from colliding molecules forms transitorily, but can lead to broad absorption bands. Collision-induced absorption dominate the far-infrared spectra of Jovian planets. This is a direct radiative effect, but the diatomic molecules also have an influence in broadening the absorption lines of the typical greenhouse substances in our atmosphere. This pressure broadening effect becomes more important as the gas pressure increases, since collisions will be more abundant. The lack of any substantial atmosphere on Mars (1/100th the pressure of Earth’s atmosphere), despite consisting mostly of CO2, cannot generate a strong greenhouse effect because of this. Figure 1 shows a typical thermal radiation spectrum emitted by the Earth (as seen from a viewer in outer space). The colored curve corresponds to the emission of Earth; the solid, light curves in the background correspond to the emission that would emanate from a “blackbody” (essentially a perfect radiator). Radiation is emitted across a spectrum of wavelengths, and the intensity at all wavelengths increases as the temperature is made higher (the family of curves shown on the diagram is the wavelength distribution of radiant intensity at various temperatures). The relevant equation to describe this relationship is the Planck law which can be integrated over all wavelengths and directions to yield . In regions where the atmosphere is transparent to thermal radiation (e.g., between 8-12 microns, with the exception of ozone) the radiation is seen (from space) to emerge from the warm surface. In contrast, at opaque wavelengths (e.g, 15 microns) the radiation from the surface is absorbed by the atmosphere and will be shielded by the viewer in space. Radiation that interacts strongly with the atmosphere can only exit to space from the upper, thin layers of the atmosphere where it is quite cold. This effect is manifested as a “dip” in spectrum at those opaque wavelengths, which of course must physically correspond to a reduction in OLR at that temperature. In fact, regions of low OLR in the tropics for instance are often used as a proxy for areas of deep convection in satellite analyses, since the low thermal radiation comes from the cold, clouds tops. Figure 1b contains the same information, except showing the transmissivity () as a function of wavelength, which approaches zero as the opacity becomes large. can be related to a quantity called optical depth, , which is a measure of the opacity. It depends on the density of the absorber and the pressure interval upon which a beam of light is traveling. At normal angle incidence, where we remember that both quantities are wavelength-dependent. Basic Radiative Transfer Let us begin with the Earth-like case in which we add a substance, such as CO2, that is opaque in the infrared but transparent to incoming solar radiation. This addition of greenhouse gas will reduce the planetary outgoing longwave radiation (OLR) as seen from an observer in space. We define a greenhouse parameter, : and now, the surface temperature becomes: Figure 2 below shows the OLR of a planet that radiates as a blackbody (in the black line) according to and the red curve shows the same situation except with 400 parts per million (ppm) of carbon dioxide added to the atmosphere. The horizontal curve is a constant Earth-like value for the absorbed solar radiation, . The equilibrium temperature must correspond to the intersection of these curves. The addition of the greenhouse substance reduces the OLR at any given temperature, since some portion of the energy is now being blocked; alternatively, the intersection point must occur at a higher temperature. We can formulate the vertical temperature profile as a function of optical depth, , employing useful approximations. We will use the so-called Eddington approximation for a “grey” atmosphere (grey meaning that the absorption is wavelength-independent, which is clearly unrealistic, but a useful starting point for conceptualizing the problem). We have, and, we can write the ground temperature, , as function of the planetary emission temperature ( as defined in the first link), where is the column infrared grey optical depth. is the air temperature at , or the skin temperature of the planet. When greenhouse gases are added to our atmosphere, the column optical-depth increases and the profile moves upward. Suppose, for instance, that the atmosphere was optically thick throughout the infrared and eventually became optically thin enough at some high altitude, such that the observer in space could only see to the level. The observer would be blind to all events happening below , much in the same way as we cannot “look into” the sun’s outer photosphere very far (as all radiation has been absorbed before exiting into space). As greenhouse gases are added, the height of the surface will move up, such that radiation does not escape to space until it reaches a higher altitude than before. Of course, where a surface is located is wavelength dependent. On the gas planets, it is not often desirable to know about the entire atmosphere right down to the interior of the planet, so for many purposes it is sufficient to consider radiation down to the point where the fluid becomes dense enough that it radiates like a blackbody. This acts like a “surface” (just in the same way that you don’t need to know the temperature profile right down to the core of the Earth in order to do atmospheric radiation). It is typical that the radiative equilibrium profile described above introduces a strong temperature discontinuity between the surface and overlying air column. This results in convection that transports heat from the surface to overlying atmosphere. The concept of radiative-equilibrium is explored, for example, in Manabe and Wetherald, 1967 (see also Isaac Held’s useful summary). Typically, if the vertical temperature discontinuity becomes too large, we think of the atmospheric temperature profile being relaxed to some critical value called the lapse rate via convection, which has a value of on Earth (where cp is a specific heat value). The actual lapse rate on Earth tends to be closer to a moist adiabat, which is less steep (-6.5 K/km or so) due to the latent heat of condensate being released which partially offsets the cooling induced by a rising parcel of air as it expands under decreased pressure. The following diagram, from Manabe and Strickler, 1964 (Figure 3 here, Figure 4 from the paper) shows a radiative-equilibrium profile along with a a dry and moist adiabatic lapse rate typical of the convecting part of Earth’s atmosphere. Lapse rates of this sort emerge in other planetary atmospheres as well. It is possible to modify the picture somewhat by including the effects of solar absorption in the atmosphere. Earth’s atmosphere is ~80% transparent to incoming sunlight, though even the energy deposited throughout the troposphere doesn’t substantially impact the above argument, as the whole column is yoked together by convection, requiring us to think about the energy budget of the whole surface+troposphere column. However, it is possible to substantially decouple the surface from the atmosphere with enough atmospheric solar absorption, or to absorb the sunlight high enough (without impacting the reflection) such that there is no communication with the surface. On Titan, this “anti-greenhouse effect” partially compensates for the traditional greenhouse influence. It arises from the absorption of sunlight by haze and CH4 in the upper atmosphere (e.g., McKay et al (1991)). This haze is opaque at visible wavelengths but is virtually transparent to thermal wavelengths, in contrast to the greenhouse case of familiarity. This is also similar to the “nuclear winter” problem, and has also been proposed to be important on early, Archean Earth. Following McKay et al (1999), with this type of solar absorption acting, the surface temperature can be expressed as: where is a measure of the anti-greenhouse effect strength (i.e., the portion of solar energy blocked by the anti-greenhouse layer but not reflected back to space). In the extreme case where there is only a strong anti-greenhouse effect acting () with no infrared opacity (), then the surface actually becomes colder than the emission temperature of the planet by a factor of (1/2)0.25. This can be imagined by envisioning a layer between the surface and space; the high-altitude layer absorbs all the solar energy, upon which it then emits half back to space and half to the surface as thermal radiation. The surface then radiates all of the emission to space, thus receiving an amount of radiation half of the incident value but returning it all to space. One could also make the atmosphere isothermal via solar absorption, in which case the greenhouse effect diminishes due to the lack of temperature differential between the surface and top of the atmosphere (recalling the definition of ). Physically, one can see this based on the infrared spectrum plotted in Figure 1. If the upper atmosphere radiated to space at the same temperature as the surface, there would be no “dips” in the spectrum and no need for the atmosphere to heat up. When a “dip” occurs, it represents a portion of energy that would have otherwise escaped to space but no longer is. This means the planet is now taking in more energy than it is losing. That lost energy “removed” from the total OLR must be accompanied by an increase in column temperature. This increases the emission at other wavelengths by an amount equal to the area of the “bite.”
WHY WAS THE ROMAN ARMY SO SUCCESSFUL? The roman army invented a method of warfare that persisted for 2,000 years. Its troops were rigorously trained and exercised and divided into small detachments under the control of officers. Roman soldiers wore effective armour , and developed tactics that allowed them to fight successfully against almost any enemy. They were particularly good at defence. They used to close ranks and protect themselves with large shields, Which deflected arrows and spears, until they reached close quarters and could use their own weapons. The group of soldiers shown above was called ‘tortoise’ formation and it proved to be impregnable against their Celtic foes.
The Romans mined for metals in every part of their empire. They sought both utilitarian metals such as iron, copper, tin, and lead, and the precious metals gold and silver. The desire for mineral resources may even have affected foreign policy. Before he invaded, Caesar knew of the rich tin deposits in Britain, a metal used in the production of bronze and in limited supply elsewhere in the empire [Caesar, 5.12]. Our knowledge of Roman mining comes from modern excavation reports of the mines and from literary sources, such as Diodorus of Sicily and Pliny. The written evidence does not discuss all aspects of mining, leaving out information such as how veins were located, what tools were used, or how drainage wheels were used to control water. When an author mentions a mine, it is rarely with enough information to identify an exact location. The mines themselves contain evidence for various processes, but we must interpret the remains. A number of Roman mines have been excavated and documented. Examples include the gold mine at Dolaucothi in Wales, and the extensive silver workings at Rio Tinto, Spain. Mining is a destructive process, so much evidence has been erased by Roman and later working. It is particularly difficult to date features such as shafts and tools. Some earlier mines, such as the Greek silver mine of Laurion, had a Roman period that may have had minimal effect on the mine features. The poor preservation of organic remains also limits the information. In Dolaucothi, for example, the investigators believe that only one board of a wooden drainage wheel survives in the mine because the other parts were burned in a fire set to loosen rock [Boon, p. 123]. Despite these limitations, it is possible to develop a picture of Roman mining. The Romans employed three techniques to recover the metals. Pliny describes them "Gold in our part of the world ... is found in three ways: first, in river deposits. ... No gold is more refined, for it is thoroughly polished by the very flow of the stream and by wear. The other methods are to mine it in excavated shafts or to look for it in the debris of undermined mountains." [XXXIII 66; Humphrey, et al., hereafter SB, p. 187] The least difficult was surface mining, where the ore was available at the surface either in streambeds or exposed on the ground. The erosive power of streams broke up the ore and the heavier metals settled to the bottom in areas of slower flow. These are called placer deposits. Where the Romans recognized metal ores on the surface, they could follow them into the ground by strip-mining the surface ("the debris of undermined mountains"), or digging short tunnels. This technique, called opencast, was used for many metals. The third technique, deep-vein mining, was the most difficult and dangerous. Only gold and silver were valuable enough to justify digging underground. After a suitable site was found, tunnels were excavated in the rock to remove the ore. Narrow vertical shafts were driven through the rock, widening out to horizontal galleries where the ore was found. Sometimes horizontal adits from a hillside were driven as well. Working below ground, the miners had to deal with the need for lighting, the dangers of poor ventilation, and the presence of water in the tunnels. Figure 1 shows the structure of a hypothetical mine. This report describes the characteristics of deep-vein mining, as well as the special problems involved. In addition to the writings of a number of Roman and Greek authors, the data come from archaeological excavation reports of Roman mines in Britain and Spain. This information is compared to practices described by Agricola in the 16th century, and activities at the colonial Reed gold mine near Stanfield, North Carolina. The Romans lacked a theoretical knowledge of geology, but they (and the Greeks before them) made observations that helped them locate ore sources. Pliny [XXXIII 67 and 98] mentions the association of particular earths with ore. Sometimes they pursued the source of placer deposits upstream to the side valleys [Davies, p. 17]. They recognized the affinity of one type of metal for another [Pliny, XXXIII 95] and that metals often occurred where different layers came in contact [Davies, p. 17]. They made limited use of adits for prospecting [Diodorus, 5.36]. All of these methods helped the Romans locate possible deposits. The same techniques were used at Reed mine, where a placer find encouraged surface digging, and eventually the excavation of adits and shafts in the hill. Colonial prospectors relied on surface signs much like those the Romans observed. Removing rock was a difficult and time-consuming process in Roman mines. Iron was used for most tools, though stone hammers and wedges have been recovered [Davies, p. 35-36]. When mining hard stone, an iron gad (a pointed bar) struck by a hammer would remove stone in flakes and dust. This gad could be socketed for a handle, held in miners' hands, or gripped with tongs [Davies, p. 32]. The Romans used single and double headed hammers weighing 5-10 pounds, with sockets for a wooden handle [Healy, p. 100]. Iron picks, usually with an 8-9 inch curved blade, were used to work softer rock [Davies, p. 32]. Other iron tools include crowbars [Davies, p. 33], battering rams ["they...batter the flint with rams carrying 150 pounds of iron", Pliny, XXXIII 71; SB, p. 188], and wedges ["they attack it with iron wedges and the rams mentioned above", Pliny XXXIII 72; SB, p. 188]. Roman mining tools excavated from Baetica, Spain are shown in Figure 2. On the bottom row are examples of a pick and a hammer. Figure 2 [after Shepherd, p. 21] The iron tools of the miner did not change into the colonial period. Agricola mentions using a gad like those found in Rio Tinto and Laurion [Forbes, p. 194], and the mine tour at Reed mine included a demonstration of how rock was removed with a gad and hammer. Ore freed from the walls could be gathered into baskets or buckets with iron rakes, spades, or hoe-like mattocks [Davies, p. 33]. Baskets of esparto grass have been recovered from Spain [Davies, p. 30], and wooden trays were found at Rio Tinto [Craddock, p. 83]. From the Greek mine of Laurion (later lightly worked by the Romans) came a bronze bowl [Davies, p. 30]. Figure 3 is a 6th century BC Greek plaque showing miners using ore baskets and a pick [Shepherd, p. 35]1. Figure 3 [after Shepherd, p. 35] We have relatively few wooden or textile items surviving from Roman times. But in the mines, we occasionally find conditions in which these are preserved. Wood was used for buckets to remove ore [Davies, p. 30]. Several wooden ladders remain, as do wooden water-lifting devices (described later). The existence of wooden wedges is inferred from a large gallery at Linares in Spain that has no tool marks on it [Davies, p. 20]. These wedges would swell when wet, cracking the rock. Leather sacks, miners' sandals and caps have also been recovered [Healy, p. 101]. At Palazuelos, Spain, an area where the Romans mined silver, was found a sculpted relief (Figure 4). It shows miners dressed in tunics with aprons of (presumably) leather to protect themselves [Rickard, JRS, p. 140]. The largest miner carries tongs in one hand, and an oil can or bell in the other. Another miner carries a type of pick, and another a lamp [Sanders, p. 321]. The depiction fits well with the mining equipment recovered from Roman mines. Figure 4 [Davies, illustration 42] With these tools, Roman miners dug vertical shafts and horizontal galleries and adits. The passages were small due to the difficulties of removing the rock. Diodorus describes mining, "...opening shafts up in many places and digging deep into the earth, [they] search for the strata rich in silver and gold. They carry on not only for a great distance, but also to great depth, extending their diggings for many stades and driving on galleries branching and bending in various directions, bringing up from the depths the ore which provides them with gain." [5.36-38; SB, p. 186] Iron tools such as the pick or gad were used to make an initial groove, and then other tools (wedges, chisels, picks) broke away the exposed ridge [Davies, p. 20]. The Roman authors do not describe this process, but it is presumably similar to quarrying blocks of building stone. It was hard work: "those individuals of outstanding physical strength break up the quartz rock with iron hammers, applying to the work not skill, but force" [Diodorus, 3.12-13.1; SB, p. 184]. Shafts were vertical or inclined passages that provided access, ventilation, and a path for ore removal. They were normally square, small (1-2 meters square), and braced with wood to prevent collapse. The circular shafts were lined with stone. The square shaft at Reed mine was similarly reinforced by timber. Many Roman shafts contain foot- or handholds for climbing, and a few ladders have been preserved [Davies, p. 23]. A shaft could be as much as 200 meters deep [Rickard, Metals, p. 447], but most are less as the placement of the ore body determined their depth. In addition to vertical shafts, horizontal adits might be driven from the hillside in to the ore body. Some adits were for ore removal, some for drainage. From the initial shaft, horizontal galleries could be driven at depth. The galleries followed the veins as they wove underground. The outline of the galleries was rectangular, with a height of only 1 - 1.5 meters and a width about 1 meter [Shepherd, p. 17]. There were some tunnels that were even smaller: "It is not possible for someone to stand upright while digging in the Samian deposits, but he must dig while on his back or side" [Theophrastus, On Stones 63; SB, p. 185]. Although he is referring to mining for clay, many galleries at Laurion were very cramped. Some galleries, such as at Rio Tinto and Dolaucothi, were slightly larger near the roof, perhaps to accommodate the men's shoulders or ore baskets borne at shoulder level [Rickard, JRS, p. 132; Manning, p. 301]. Rarely galleries were quite long, such as the 2.2 km ones Pliny ascribed to Hannibal [XXXIII 96]. The galleries were supported by wood bracing, called 'propping' ["The earth is held up with wooden supports", Pliny XXXIII 68; SB, p. 187] or by pillars of unmined rock. The rock pillars were critical, and there was a penalty of death if these were mined [Plutarch, 843d]. The danger of roof collapse was always present, as evidenced by the crushed skeletons found in Asia Minor and a passage by Statius describing a miner crushed under the rock [6.880-885]. In the lex Vipasca (a contract for the lease of the imperial mines, second century AD), wood propping was obligatory [Bruns, p 293-5; SB, p. 180.] Besides the iron tools, the Romans used fire to fracture the rock for removal. Pliny mentions breaking up flint by means of fire and vinegar [XXXIII 71], and Diodorus talks of "burning the hardest of the gold-bearing matrix with a great fire and making it friable" before crushing the stone by hand [3.12-13.1; SB, p. 184]. Many ancient authors, including Livy [XXI.XXXVII.2] and Vitruvius [VIII.3.19] mention fire-setting and vinegar. The vinegar would have produced additional fracturing from the rapid fall in temperature. Modern geologists question the value of the vinegar over any other cold liquid [Craddock, 33-35; Shepherd, p. 23-24], but given the frequent mention made of it, vinegar was probably used. Fire-setting continued to be done through Agricola's time [Craddock, p. 34], until explosives were developed. At Reed mine, black powder was available and fire-setting was not used. Once broken up, the ore had to be brought to the surface for further processing. Diodorus [3.13.1] mentions boys scrambling through the tunnels, and Pliny [XXXIII 71] describes a relay of miners carrying the ore out on their shoulders. Figure 3, the Greek plaque, shows smaller individuals handling the ore baskets. Presumably the boys could move more easily in the low-ceilinged tunnels. Baskets, buckets, sacks or sleds would have been filled with ore and transported either to an adit mouth or the bottom of a shaft. The Romans did not use a wheeled cart, as Agricola described, but wooden trays from Rio Tinto look like those published in Agricola's De Re Metallica [Craddock, p. 83]. Once at the shaft bottom, the ore could be carried up with the miner, using the ladders or handholds cut in the sides. Alternatively, the ore container could be raised with a rope. Rope marks on shaft sides are taken as evidence of this [Shepherd, p. 43-44]. There is evidence for a wheel or windlass at the top of a shaft from Rio Tinto [Healy, p. 102]. Ore was raised up the shaft at Reed mine by a rope attached to a "kibble", an iron bucket. The colonial practice is quite close to the Roman one. The deep mine workings created problems with ventilation, lighting, and drainage. The Romans knew the dangers of bad air in the mines. Pliny writes, "The fumes from silver mines are harmful to all animals" [XXXIII 98; SB, p. 175], and "when well shafts have been sunk deep, fumes of sulfur or alum rush up to meet the diggers and kill them" [XXXI 49; SB, p. 190]. Similar passages occur in Lucretius [6.808-815], Strabo [12.3.40], and Vitruvius [8.6.12]. The latter author mentions lowering a lamp into a (well) shaft to determine if the air is dangerous. In addition to bad air, the mines were hot. For every 30 meters deeper, the temperature increased 1 degree Centigrade [Healy, p. 82]. The depiction of Greek miners (Figure 3) working naked shows that heat was a common problem. The use of fire-setting (described above) to drive galleries could only have added to the ventilation problems. To overcome the problems of heat and toxic gases, the Romans created additional air movement through convection. This could be done by cutting additional shafts in parallel, as was done at Rio Tinto [Davies, p. 24], so that the warmer air from the mine rose and was replaced by cooler air from outside. Theophrastus described this, "They make ventilation shafts, so that the air is thinned by movement" [Concerning Fire 24; SB, p. 190]. Vitruvius, in the same passage that described the lighted lamp down the well to detect gases, says "but if the flame is snuffed out by the power of the gas, then ventilation shafts are to be dug next to the well on either side. In this way the gas vapours will be dissipated through the shafts as through nostrils" [8.6.13; SB, p. 289]. Davies [p. 24] thinks shallow grooves on some shaft walls were used for boards to separate a single shaft into an up and down draft. Fires could also be set to increase air movement, a practice mentioned by Theophrastus [Concerning Fire 70], but these would have to be carefully placed to avoid adding to the ventilation problems. Interconnecting galleries and frequent cross-cuts as found at Rio Tinto would also have increased air flow [Davies, p. 23-4]. Pliny refers to waving linen strips [XXXI 49] to move the air, a practice also illustrated by Agricola [Craddock, p. 75]. Poor ventilation remained a serious problem in Roman times. The miners often spent long periods in the dark, with only oil lamps for lighting. Pliny says that the lamps measured the periods of work [XXXIII 70], perhaps a daily shift of 8 or 10 hours. The miners used oil lamps like those found in Roman homes. These were stone or terracotta dishes with a wick [Figure 5]. The lamps were found in niches in the walls [Forbes, p. 210]. Diodorus [3.12.6] mentions lamps mounted on the miners' heads, but there is no other evidence of this. At Reed mine, the candles were worn on the heads of the miners. Mounting the lamps would bring the light where the miner needed it. Torches could have been used for light as well, but they would have added to the ventilation problems. Figure 5 [after Shepherd, p. 41] The control of underground water could determine the viability of a mine. This water comes from percolation from above the mine, or more rarely, from digging into the sea or a subterranean river [Shepherd, p. 35]. Many mines simply stopped at the water table. Mines that went below quickly filled with water when abandoned. While they were being worked, the Romans used several methods for handling the water. They could drive drainage adits below working levels, use slaves to bail the workings, or employ one of two mechanical devices. Diodorus states that "at a depth they sometimes break in on rivers flowing beneath the surface whose strength they overcome by diverting their welling tributaries off to the side in channels" [5.37; SB, p. 186]. Occasionally water could be diverted into a natural fissure, but the miners drove artificial channels as well. Drainage adits, also called cross-cuts, are found at some sites such as Dolaucothi and Rio Tinto [Davies, p. 24]. Water drained from upper workings into the adit, but during the digging of the adit, the water had to be handled by another method. Where the flow was not strong, and labor was available, bailing could control the water. Pliny tells of Hannibal using a line of water-bearers along a 2.2 km gallery [XXXIII 97]. Baskets of esparto grass waterproofed with pitch, and bronze or wooden buckets, have been found in the mines [Forbes, p. 211]. The buckets could hold 150 liters and their bottoms were pointed so they tilted automatically to be filled [Davies, p. 25]. Their shape and weight when filled suggest that they were hauled out of the mine by means of a winch. From the first century AD, Roman miners had access to two water-lifting devices. The earlier one is the Archimedean screw, or cochlea. Diodorus describes the use of the screw: "They draw off the streams of water with the so-called Egyptian screw, which Archimedes the Syracusan invented when he visited Egypt. By means of these devices, set up in an unbroken series up to the mouth of the mine, they dry up the mining area and provide a suitable environment for carrying out their work. Since this device is quite ingenious, a prodigious amount of water is discharged from the depths into the light of day" [5.37; SB, p. 186]. Vitruvius [10.6.1-4] described the construction of the screw in detail. It consisted of a hollow wooden cylinder (the case) with a wooden helical screw inside (the rotor). The rotor had wooden or copper vanes, around a central wooden core, which was attached to the case with an iron pivot. A single person, treading on the cleats around the center of the case or turning a crank, could operate this screw and raise water from one end to the other. A 3 meter screw would raise water approximately 1 meter, and they were often placed in series to raise water to a drainage adit [Craddock, p. 78-79]. Vitruvius specified an angle of 37˚ for the screw from the ground. Various inefficiencies reduce its output. There was friction in the rotor shaft bearings, and some water loss due to the uneven movement of the rotor. Landels estimates the efficiency at 40 - 50%, which would produce 35-40 gallons per minute when the screw is mounted as Vitruvius specified [Landels, p. 63]. Contemporary depictions of screws in use are known from a Pompeii wall painting [Forbes, p. 213] and an Egyptian terracotta [Rickard, Metals, p. 425], but neither portrays a mine. A number of screws have been recovered from Roman mines. An example from Sotiel Coronada, a Spanish mine, is 3.6 meters long and 48 centimeters in diameter, and was one of three in series [Forbes, p. 214]. One screw poured water into a sump, from which the next screw moved it further upward. One screw from Centenillo was slightly larger: length 5 m, diameter 59 cm with a core 20 cm thick [Shepherd, p. 40]. The angle of the Coronada screws is 15-20˚, while those from Centenillo were 35˚ [Davies, p. 28]. The difference in size may have affected the angle chosen. One from Alcaracejos had an iron crank for turning [Davies, p. 27]. With Diodorus' account, and archaeological evidence from a number of mines, the screws appear to have been in widespread use in the Roman Empire. The other water-lifting device, the water-wheel, came into use slightly after the screw. Unlike water-wheels familiar from colonial sites, this was powered by men rather than by water. Vitruvius described two types, one with a compartmented body and the other with a compartmented rim. His description of the latter: "A wheel will be built around the axle, of a large enough diameter so that it can reach the height which is required. Rectangular compartments will be fixed around the circumference of the wheel and made tight with pitch and wax. Thus, when the wheel is turned by men treading it, the containers will be carried up full to the top of the wheel and on their downward turn will pour out into a reservoir what they have themselves raised [10.4.2; SB, p. 311]". On the compartmented rim wheel, the rim contained sections with holes for the water to flow in and out. At the bottom of the course of the wheel, the hole was submerged in the sump and the compartment filled. Near the top, the hole discharged the water into an adjacent trough, called a launder (Figure 6). Archaeological remains are compatible with Vitruvius' description [Boon, p. 124]. \| Figure 6 [after Landels, p. 68] \| Figure 7 [after Landels, p. 70] The wheels found are usually 4-6 meters in diameter with 20-24 compartments. Each has an axle of bronze or wood, and an oak hub around the axle. Spokes, secured with tree nails, connect the hub and compartmented rim. Numbering found on a Roman wheel from Rio Tinto suggests that the wheels were prefabricated in a more spacious location, before being erected in the mine. The rim was continuous with dividers (Figure 6), rather than containing separate buckets that carried the water. On the outside of the compartments were wooden cleats [Shepherd, p. 37-8]. Vitruvius mentions that men tread on the water-wheels to turn them [10.4.2], but gives no specifics. Wear patterns on the cleats confirm that some wheels were turned this way (Figure 7). Some cleats project from the side of the rim, parallel to the axle. These wheels could be turned by hand or pushed by men's feet. One wheel in Tharsis (Spain) had bits of rope surviving, suggesting it could be pulled by hand [Shepherd, p. 37-8]. The wheel could raise water higher than the screw, but moved less water per minute. The height raised was approximately 3/4 the height of the wheel, limited by how water fell from the compartment holes near the top of the rise, and also by the depth the wheel reached into the sump. The wheels delivered approximately 19 gallons per minute for a 12-foot rise [Landels, p. 69]. Landels calculated that the power required to operate a wheel would be 0.1 hp, which one man could produce and continue to produce over 8 hours [p. 69]. Though constructed mainly of wood, waterwheels are preserved at a number of Roman mines. Part of a water wheel was found in the Dolaucothi mines of South Wales, 9 wheels were found at San Domingos in Portugal, and other examples are known from Dacia [Davies, p. 26-7]. Wheels were often used in series so that the output of one wheel became the input of another. At Rio Tinto, 8 pairs of wheels in series were found, which combined could raise water 30 meters [Forbes, p. 217]. The counter-rotating pairs of wheels (Figure 7) reduced the turbulence and decreased the slight downward slope required for one pair to feed the next level [Healy, p. 99]. Whether in pairs or as singles, special sump chambers had to be excavated in the mine to hold the wheels. Water control was a serious problem for the Roman miner, and all the possible solutions (except abandonment) required a substantial commitment of resources. Deep-vein miners had to deal with a number of difficult problems, including drainage, ventilation, lighting, and safety. Comparison of the Roman, medieval, and colonial practices shows that many techniques remained the same up to the last century. Likely mine sites were identified by surface finds. Ore was extracted and removed by iron hand tools, and lifted up the shaft using a rope. In the 16th century, miners were still using fire-setting and wooden trays. In 1600 years, mining technology progressed very little beyond the Roman practices. Date: December 9, 1999
We have already reviewed their first three questions and answers: - Why does the Common Core include disciplinary literacy standards? 3. But don’t disciplinary subjects have their own standards already? This week we will discuss their next question which is: 4. If teachers in science, social studies, and other subjects are teaching disciplinary literacy, what are English teachers doing? English teachers do have disciplinary skills they are responsible to teach. For example, literature is one of those areas. Understanding novels, short stories, poems, etc. demands a specific skills set. Figurative language and the use of symbolism are other areas of disciplinary knowledge and skills unique to the English classroom. In addition to their own specific skills, English teachers also teach general literacy skills that can be applied across disciplines. They often teach fundamental vocabulary, reading comprehension, grammar, etc. These base skills can be transferred to any area of study; however, other teachers need to then extend on these basics within each specific discipline for ultimate student success.
Paracentesis is a surgical procedure in which a needle is inserted into the peritoneal cavity – the space between the two membranes that separate the organs in the abdominal cavity from the abdominal wall – in order to remove excess peritoneal fluid, also known as ascitic fluid. This procedure, which is sometimes called an abdominal or ascites tap, may be used for diagnostic or therapeutic purposes. Chat with a Patient Advocate about treatment options and get help finding a specialist. While the body normally maintains a sufficient supply of ascitic fluid as a lubricant and anti-inflammatory agent, a buildup of surplus fluid, called ascites, is a disorder that can be the result of infection, injury or a serious condition like cirrhosis of the liver or cancer. A paracentesis, and subsequent analysis of the withdrawn ascitic fluid, can help determine the underlying cause of the ascites. Peritoneal mesothelioma, a rare form of cancer caused primarily by the ingestion of asbestos fibers, is often accompanied by ascites in the peritoneal cavity. Patients with peritoneal mesothelioma-induced ascites might undergo a paracentesis to help verify the diagnosis, or more often, to alleviate stomach pain or difficulty breathing because of increased abdominal pressure caused by excessive fluid buildup (ascites). Ascites develop in people with this disease because the peritoneal tumors cause a condition known as peritoneal carcinomatosis. This condition occurs when tumors are widespread throughout the abdomen. These tumors block the lymphatic system that normally regulates the flow of fluid in and out of the abdomen. Peritoneal mesothelioma tumors also weaken the endothelial cells in the abdominal wall. Endothelial cells normally function as barriers against various fluids in the walls of blood vessels. When these cells are weakened, fluids that contain protein and lipids (fat cells) leak out from blood vessels and accumulate in the peritoneal cavity. Paracentesis is effective in helping patients manage the symptoms of ascites. However, over time, the fluid may become loculated, meaning it builds up in smaller spaces in the abdomen and does not flow freely in the peritoneal cavity, making it more difficult to drain. When this occurs, the procedure loses some of its effectiveness in draining fluid, and doctors may develop an alternative method for controlling fluid buildup. We can help you or a loved one find a mesothelioma doctor who specializes in performing a paracentesis. When performing a diagnosis using this procedure, a smaller amount of fluid may be obtained in a syringe. Pathologists study the cells found in the drained ascitic fluid. As a diagnostic tool for peritoneal cancer, paracentesis is less reliable than a biopsy because the cells in the ascetic fluid can sometimes appear benign. Doctors may try to diagnose the disease through with this procedure before performing a laparoscopy to obtain a tissue sample (because biopsies help to make a more definitive diagnosis). Unlike a peritonectomy, which is a major surgery used to remove cancerous tumors from the abdominal cavity, a paracentesis is a minor surgery and first-line treatment option that can improve the quality of life for a person with peritoneal mesothelioma. Since ascites often reoccur with peritoneal mesothelioma, repeated therapeutic paracenteses can be administered as palliative care in patients with advanced stages of this disease. Fast fact: When performing a paracentesis for diagnosis, 50 ml of fluid is taken from the peritoneal cavity. During a therapeutic paracentesis, no more than 1 L can be taken at a time. This procedure is often performed as an out-patient procedure, taking approximately 20 to 30 minutes. Sometimes, an ultrasound is first administered to better visualize the size and scope of the ascitic fluid buildup. After the bladder is emptied, patients are placed in bed with their head elevated at a 45 degree angle to allow fluid to accumulate in the lower abdomen. The insertion site is then cleaned with antiseptic and numbed before a large-bore needle is inserted to reach the peritoneal cavity. Once the fluid begins to flow, the needle is removed and the cavity is drained via an intravenous catheter, either by gravity, a syringe, or by connection to a vacuum bottle. After the desired level of drainage is complete (no more than 500 ml in 10 minutes, and only one liter at a time, so that the body can equilibrate fluids and electrolytes), the catheter is withdrawn and the insertion site is covered with a sterile dressing and a small suture, if necessary. Alternatively, if the procedure is going to be repeated, a catheter with a flow control valve and protective dressing can be left in place. If more than 5 liters of fluid is drained during the procedure, the patient may receive serum albumin to replace lost fluids, prevent a drop in blood pressure, or reduce the risk of shock. The patient is usually discharged within a few hours, provided that blood pressure is normal and there is no feeling of dizziness. A paracentesis is a fairly simple procedure that presents very few risks. If peritoneal mesothelioma cells are present, there is a chance they could spread (called "seeding") to the site where the needle was inserted. To make sure this doesn't occur, radiation therapy may be used along the site of the incision. One documented complication that occurred in a patient with peritoneal mesothelioma was the repeated occurrence of a pneumothorax after a paracentesis procedure. A pneumothorax occurs when air builds up in the space around the lungs and doesn't allow the lung to expand fully. This is a rare complication, but doctors feel it should be considered in patients with pre-existing pulmonary disease. Fast fact: The administration of albumin helps reduce morbidity and mortality in cirrhotic patients undergoing large-volume paracentesis caused by severe ascites. Because peritoneal mesothelioma is rare, few studies have been done on the effectiveness of this procedure for this disease. While it is accepted as an effective method to control ascites, patients with the disease have a high rate of ascites recurrence. A disadvantage to paracentesis is that the patient must go to a hospital to have this procedure done. This can become costly and uncomfortable. If the patient necessitates frequent procedures, doctors may recommend the placement of a catheter instead. In one study, a person who developed peritoneal mesothelioma was surgically fitted with a Tenckhoff catheter when his ascites did not respond to conservative management. The doctors were not in favor of frequent paracentesis as a primary treatment for the removal of excess fluid. The patient's symptoms were well controlled, and the catheter drained approximately 1 liter of fluid a day without the need for a hospital visit. Some studies involving the use of paracentesis as a diagnostic tool show that the procedure is not always effective. In one case report, the procedure proved insufficient for an accurate diagnosis. Ascites were monitored for malignant cells, and multiple therapeutic paracentesis procedures routinely showed benign cytology. It wasn't until doctors conducted a PET scan and immunohistochemistry staining with cells obtained through fine needle aspiration that the diagnosis was made. View our resources for patients and familiesGet Help Today
Layman’s Guide To El Nino By Paul Homewood Given that El Nino is making big news at the moment, I thought it would be useful to publish this short resume from NWS on ENSO processes: Normally, sea surface temperature is about 14°F (8°C) higher in the Western Pacific than the waters off South America. This is due to the trade winds blowing from east to west along the equator allowing the upwelling of cold, nutrient rich water from deeper levels off the northwest coast of South America. Also, these same trade winds push water west which piles higher in the Western Pacific. The average sea-level height is about 1½ feet (46 cm) higher at Indonesia than at Peru. The trade winds, in piling up water in the Western Pacific, make a deep 450 feet (150 meter) warm layer in the west that pushes the thermocline down, while it rises in the east. The shallow 90 feet (30 meter) eastern thermocline allows the winds to pull up water from below, water that is generally much richer in nutrients than the surface layer. El Niño Conditions However, when the air pressure patterns in the South Pacific reverse direction (the air pressure at Darwin, Australia is higher than at Tahiti), the trade winds decrease in strength (and can reverse direction). The result is the normal flow of water away from South America decreases and ocean water piles up off South America. This pushes the thermocline deeper and a decrease in the upwelling. With a deeper thermocline and decreased westward transport of water, the sea surface temperature increases to greater than normal in the Eastern Pacific. This is the warm phase of ENSO, called El Niño. The net result is a shift of the prevailing rain pattern from the normal Western Pacific to the Central Pacific. The effect is the rainfall is more common in the Central Pacific while the Western Pacific becomes relatively dry. La Niña Conditions There are occasions when the trade winds that blow west across the tropical Pacific are stronger than normal leading to increased upwelling off South America and hence the lower than normal sea surface temperatures. The prevailing rain pattern also shifts farther west than normal. These winds pile up warm surface water in the West Pacific. This is the cool phase of ENSO called La Niña. What is surprising is these changes in sea surface temperatures are not large, plus or minus 6°F (3°C) and generally much less. El Niño effect during December through February El Niño effect during June through August La Niña effect during December through February La Niña effect during June through August As the position of the warm water along the equator shifts back and forth across the Pacific Ocean, the position where the greatest evaporation of water into the atmosphere also shifts with it. This has a profound effect on the average position of the jet stream which, in turn, effects the storm track. During El Niño (warm phase of ENSO), the jet stream’s position shows a dip in the Eastern Pacific. The stronger the El Niño, the farther east in the Eastern Pacific the dip in the jet stream occurs. Conversely, during La Niña’s, this dip in the jet stream shifts west of its normal position toward the Central Pacific. The position of this dip in the jet stream, called a trough, can have a huge effect on the type of weather experienced in North America. During the warm episode of ENSO (El Niño) the eastern shift in the trough typically sends the storm track, with huge amounts of tropical moisture, into California, south of its normal position of the Pacific Northwest. Very strong El Niños will cause the trough to shift further south with the average storm track position moving into Southern California. During these times, rainfall in California can be significantly above normal, leading to numerous occurrences of flash flood and debris flows. With the storm track shifted south, the Pacific Northwest becomes drier and drier as the tropical moisture is shunted south of the region. The maps (right) show the regions where the greatest impacts due to the shift in the jet stream as a result of ENSO. The highlighted areas indicate significant changes from normal weather occur. The the magnitude of the change from normal is dependent upon the strength of the El Niño or La Niña. Tropical cyclone activity in the North Atlantic is more sensitive to El Niño influences than in any other ocean basin. In years with moderate to strong El Niño, the North Atlantic basin experiences: - A substantial reduction in cyclone numbers, - A 60% reduction in numbers of hurricane days, and - An overall reduction in system intensity. This significant change is believed to be due to stronger than normal westerly winds that develop in the western North Atlantic and Caribbean region during El Niño years. Other regions around the world show no affect or are only slightly affected. The table below gives the trend in number and intensity of cyclones around the world due to the effects of El Niño. (However, as with most meteorological phenomena, there are always exceptions to these trends).
Inference vs. Implication Difference Between Inference And Implication In the science of statistics, inference is the process of using information from observed phenomena to derive conclusions about the underlying probability distribution of the observations (see distribution, statistics). Suppose a coin is known to have some unknown probability p of coming up heads. (In most cases, p will not be ½ and the coin will be biased.) Assume that in a coin-tossing experiment, 70 heads were observed out of 100 tosses. Two typical problems of inference are (1) to decide whether or not the coin is biased and (2) to estimate the value of p. The first of these questions is an example of hypothesis testing: the null hypothesis that the coin is unbiased is being tested. The second question is a problem in estimation; it does not seek a simple yes or no answer but rather an estimated value of a parameter of interest. In estimation, some measure of the precision of the estimate is also sought. This may take the form of the variance of the estimate in (hypothetical) repeated sampling. Alternatively, instead of giving a point estimate and the variance, there are ways of giving a confidence interval, with ends computed from the data, that will include the true value in some specified fraction of hypothetical repetitions. Implication, a term in logic usually denoting “logical” (or “strict”) implication, although it sometimes denotes the weaker relation of “material” implication. Likewise, a group of statements logically implies B if, and only if, it is not possible for every statement in the group to be true while B is false. The statement “Mount McKinley is taller than Mount Logan, which is taller than Mount Rainier” logically implies the statement “Mount McKinley is taller than Mount Rainier.” It is not possible for the first of those statements to be true while the second is false. Logical implication differs from material implication. To say that a statement, A, materially implies another statement, B, is to say merely this: it is not the case that A is true and B false. Any pair of true statements materially imply each other because, given that both are true, it is not the case that the first is true and the second false. Nevertheless, not every pair of true statements logically imply each other, for in many cases either of the two could be true even if the other were false.
Orientation and mobility (O&M) is a foundational skill for people who are blind or have low vision. But what is O&M? Orientation means knowing where you are in space, in relation to the things around you. It means you can answer the following questions: - Where am I now? - Where am I going? - How am I going to get there? Mobility refers to how a person moves through their environment. This can involve the use of a mobility aid such as a long cane or a guide dog, learning strategies to use functional vision safely and effectively, or a combination of the two. An Orientation & Mobility Specialist is a professional trained to teach people who are blind or have low vision how to move through the environment safely, efficiently and as independently as possible. This is done through the development of both orientation and mobility skills. Within the education sector, orientation and mobility is a component of the “expanded core curriculum” – those concepts, skills and learning areas that sighted children learn incidentally and through vision. Children who are blind or have low vision need to be specifically taught some or all of these skills alongside the academic curriculum. The expanded core curriculum consists of: - Compensatory or functional academic skills, including communication modes such as braille - Orientation and mobility - Social skills - Independent living skills - Recreation and leisure skills - Career education - Sensory efficiency skills You can find out more about the expanded core curriculum on our website: We’ll talk about how to develop specific orientation and mobility techniques in future posts!
Howard Gardener’s definition of intelligence uses 3 primary and overarching categories: - ability to create an effective product or service that is valued in a culture - set of skills that make it possible for a person to solve problems in life - the potential for finding or creating solutions to problems, which involves gathering new knowledge The next two phases of the 5 E Lesson Plan are Explore and Explain. During these two phases, students will be asked to use and expand their intelligence to identify and develop concepts, processes and skills. During the 2nd E (Explore) Phase students are required to actively explore their environments and manipulate materials. They will then connect the dots from Exploring to learning the lesson plans concepts. The teacher will give the students different opportunities to verbalize the lesson’s concepts and demonstrate the new behaviors and skills. Teachers will often rely on different methods to help students retain the information such as word charts, think-pair-share or graphic organizers. The 3rd E (Explain) Phase should include intentional play which will allow children to develop self-regulatory skills, supports communication and fosters collaborative learning. The 5-E Lesson Plan uses a constructivist approach. Constructivism is a learning strategy that was developed by Jean Piaget and become popular during the 1960s. The constructivist method or approach allows students to synthesize new understanding from prior knowledge and helps students build on the past to develop new information.
Top of the page A dental sealant is a strong liquid-plastic material that helps protect teeth from plaque. Plaque is a thin film of bacteria that sticks to teeth. The bacteria in plaque use sugars in food to make acids. These acids can damage the tooth's surface and cause tooth decay. The sealant is put on the chewing surfaces of the back teeth (molars). These teeth are more likely to develop tooth decay because food and bacteria easily get stuck in the pits and grooves of the surface. Some pits and grooves are so small that a toothbrush can't clean them out. Sealants bond to the tooth's enamel. Enamel is the hard surface of the tooth. It covers the dentin, which protects and surrounds the tooth pulp. The pulp is the core of the tooth, the place where nerves and blood vessels are. A dental sealant does not take the place of good dental care and use of fluoride toothpaste and mouthwash. It's still important to brush and floss daily. Sealants can be used in children, starting at about age 6, and in teens and adults. Dental sealants may wear down over time, but they can protect teeth from decay for years. Your dentist can check them and reapply them if needed. Current as of: November 14, 2022 Author: Healthwise Staff Medical Review:Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Arden Christen DDS, MSD, MA, FACD - Dentistry To learn more about Healthwise, visit Healthwise.org. © 1995-2023 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Scientists at the University of Manchester have created the most complex shaped molecule developed in a lab so far, a six-pointed Star of David molecule with interlocking rings, as reported by the Washington Post. The possibilities for innovation with this intricate shape are immense. Scientist David Leigh said the inspiration came from viruses (not the computer kind), “When you look at viruses, some of their shells have these coatings made of a chainmail protein, and it’s very tough but very light. So the thinking is if you could do the same thing with a man-made molecule, you could get the same benefits.” Will you offer us a hand? Every gift, regardless of size, fuels our future. Your critical contribution enables us to maintain our independence from shareholders or wealthy owners, allowing us to keep up reporting without bias. It means we can continue to make Jewish Business News available to everyone. You can support us for as little as $1 via PayPal at [email protected]. It has taken some scientists 25 years to figure out how to create the design. At first they attempted to weave linear molecules around each other, but Leigh discovered the trick was to allow them to assemble themselves. The result is that two molecular triangles interweave three times to create a star with a perimeter of only 114 atoms. This is only the beginning of new shapes and more possibilities for the lab-created molecules. Since the shape happens to be a Star of David, the discovery was dedicated to Chaim Weizmann, the first President of Israel, who spent 12 years as a chemistry professor at the University of Manchester, where the molecule was developed.
Pipistrelle bats have a magnetic compass and calibrate it at sunset, according to a new study published in the journal Biology Letters. The research shows that these animals, like birds, are sensitive to magnetic inclination. The soprano pipistrelle (Pipistrellus pygmaeus) weighs only a few grams, but it is estimated that members of this small bat species cover thousands of kilometres every year on their nocturnal migrations from north-eastern to south-western Europe. Precisely how they find their way across such long distances in the dark remains unclear. However, an international team led by biologist Dr Oliver Lindecke from the University of Oldenburg has found evidence suggesting that a magnetic sense may play a role in the bats' navigation. In behavioural experiments, the team discovered that two different components of the Earth's magnetic field influence the animals' orientation. The study has now been published in the scientific journal Biology Letters. Lindecke has already been studying the migratory behaviour of the small mammals for ten years. "Unlike with birds, so far there has been very little research into the magnetoreception of mammals that migrate over long distances," he explained. Together with earlier findings, the results of the current study indicate that soprano pipistrelles have a magnetic compass which they calibrate at sunset. Bat migration along the Latvian coast Lindecke and his colleagues conducted their experiments at the University of Latvia's Ornithological Station in Pape, a village on the Baltic Sea coast in the far south-west of Latvia. "Tens of thousands of bats migrate along the coast here in August and September, mainly towards Central Europe," Lindecke explains. He had already discovered in an earlier study that these migratory bats readjust their internal orientation system at sunset: they use the point at which the sun sets for calibration to be able to pick their flight route later that night. To test whether the bats have a magnetic sense and use it for navigation, the researchers trapped 65 soprano pipistrelles. The following day at sunset, a number of these bats were exposed to a manipulated magnetic field created using a device called a Helmholtz coil. The horizontal component was rotated 120 degrees clockwise in relation to the Earth's magnetic field, such that a compass needle would point south-east rather than north. With a second group of bats, in addition to the horizontal shift the research team also reversed the inclination of the magnetic field so that it corresponded to the natural values measured in the Earth's southern hemisphere. A third group was used as a control group and exposed only to the natural geomagnetic field in the dunes on Pape beach. A few hours later the researchers released the bats one by one in a field lab set up inside a Mongolian yurt at the Pape Ornithological station site in order to determine their take-off orientation. Earlier work had already shown that the animals maintain their chosen direction during their nocturnal flights. Magnetic field influences take-off behaviour several hours later The results: around half of the bats in the control group flew southwards, while the other half flew northwards. The two groups exposed to manipulated magnetic fields behaved differently from each other: the bats that had been exposed to a horizontal shift of the magnetic field generally took off in a north-westerly direction. In the group where, in addition to the horizontal shift, the inclination was also reversed, however, no discernible preferred direction of take-off was observed. These results demonstrate one thing in particular, says Lindecke: "The bats are sensitive to both the magnetic field's horizontal component, known as polarity, as well as its inclination at sunset -- and this still influences their take-off behaviour several hours later." Lindecke explained that although it is not yet clear which mechanisms the magnetic compass in migratory bats is based on, the study had shown that, like birds, migratory bats may use the inclination of the Earth's magnetic field for navigation. The University of Oldenburg's Collaborative Research Centre (CRC) Magnetoreception and Navigation in Vertebrates, which has been funded by the German Research Foundation (DFG) since 2018, is investigating the mechanisms and interconnections involved in the process. Lindecke has been a fellow of the CRC since 2021 and is heading a sub-project focused on migratory bats since 2023. The CRC also funded part of the current study. Researchers from Bangor University in the UK and the University of Latvia were also involved in the publication. Cite This Page:
Homologous vs Analogous Analogous characters and homologous characters are characters used in phylogenetic analysis. When a group of organisms has a homologous structure, which is specialized to perform a variety of different functions, it shows a principle known as adaptive radiation. For an example, all the insects share the same basic plant for the structure of the mouth parts. A labrum, a pair of mandibles, a hypopharynx, a pair of maxillae and a labium together form the basic plan of the mouth parts structure. In certain insects, certain mouth parts are enlarged and modified, and others are reduced and lost. Due to this they can utilize a maximum range of food material. This gives rise to a variety of feeding structures. Insects show a relatively high degree of adaptive radiation. This shows the adaptability of the basic features of the group. This can also be called the evolutionary plasticity. This has enabled them to occupy a wide range of ecological niches. A structure present in an ancestral organism becomes greatly modified and specialized. This can be called a process of descent by modification. The significance of adaptive radiation is that it indicated the existence of divergent evolution, which is based on the modification of homologous structures over time. Structures and physiological processes can be similar in organisms that are not closely phylogenetically related and they may show similar adaptations to perform the same function. These are referred to as analogous. Some examples for analogous structures are eyes of vertebrates and cephalopods, wings of insects and birds, jointed legs of vertebrates and insects, thorns on plants and spines on animals etc. Similarities found in analogous structures are only superficial. For example, insect wings and wings of bats and birds are analogous structures, but the wings of the insects are supports by veins composed of cuticle and the wings of birds and bats are supported by bones. Also, vertebrate eyes and cephalopod eyes are analogous structures, but the embryological development of the two is different. Cephalopods have erect retina and photoreceptors facing the incoming light. In contrast, in vertebrates the retina is inverted and the photoreceptors are separated from the incoming light by the connecting neurons. Therefore, the vertebrates have a blind spot and the cephalopods do not have a blind spot. Convergent evolution is supported by the presence of analogous structures. What is the difference between Homologous and Analogous Characters? • Characters that are similar in function but have different evolutionary origins are known as analogous characters, whereas characters that have the same evolutionary origin are known as homologous characters. • Analogous characters cannot be used to infer evolutionary relationships between taxa whereas homologous characters are used to construct evolutionary relationships and phylogeny of taxa.
Caring for a pet involves more than providing food, shelter, and affection. It also includes taking preventative measures to keep them healthy. One such vital measure is vaccination. Vaccines play a crucial role in protecting pets from various diseases, some of which can be life-threatening. In this comprehensive guide, we’ll delve into the significance of vaccines for pet health, the types of vaccinations available, and the diseases they safeguard against. Just as in humans, vaccines work to stimulate the pet’s immune system to produce a defensive response. When your pets are exposed to viruses or bacteria contained in a vaccine, their immune system will memorise the disease-causing agent. If your pets encounter that same agent in the future, their immune system will recognise it and launch a robust response to combat it. Vaccines, though simple in delivery, initiate a complex biological process that bolsters the health of your pets. They provide immunity against a range of diseases, many of which can be fatal. Without vaccines, your pets are left vulnerable to these diseases, which could impact their quality of life or even cut their lives short. In the subsequent sections, we will dissect the different types of vaccines, the diseases they prevent, and what kind of pets may need them. Core vaccines are those considered essential for all pets, regardless of lifestyle or location. They protect against diseases that are highly infectious, usually severe, and in some cases, transmittable to humans. For cats, the feline core vaccines prevent diseases such as feline calicivirus, feline herpesvirus type I (rhinotracheitis), and panleukopenia. Rabies is also a core vaccine for cats. These diseases are all highly infectious and can result in severe clinical symptoms in unvaccinated cats. In dogs, the canine core vaccines safeguard against canine parvovirus, distemper, canine hepatitis, and rabies. Much like the diseases covered by the feline core vaccines, these infections can be lethal in unvaccinated dogs. Non-core vaccines are those recommended on a case-by-case basis, depending on a pet’s specific risk factors, such as their geographical location, lifestyle, age, and breed. These vaccinations protect against diseases that are not typically life-threatening but can still cause significant discomfort or illness. In cats, non-core vaccinations may include those for feline leukemia, feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP), and Bordetella. For dogs, non-core vaccines might include those for leptospirosis, Bordetella bronchiseptica, Lyme disease, and canine influenza. The timing and frequency of vaccinations can vary depending on many factors, including the type of vaccine, the pet’s age, medical history, environment, and lifestyle. Typically, puppies and kittens receive a series of vaccines starting from a young age, with booster shots administered at regular intervals. For instance, puppies usually get their first round of core vaccines between six and eight weeks of age, followed by boosters every two to four weeks until they reach 16 weeks. Adult dogs may need boosters annually or every three years, depending on the vaccine. Similarly, kittens typically begin their vaccination regimen at around six to eight weeks old, with boosters given every three to four weeks until they reach around 16 weeks. Adult cats may also need boosters annually or every three years. Vaccines are extensively tested and proven safe for most pets. However, as with any medical procedure, there are risks. Some pets may experience mild side effects such as soreness at the injection site, fever, or decreased appetite. Serious reactions are rare but can occur. Despite these risks, the benefits of vaccination far outweigh any potential downsides. Vaccines have saved countless pets’ lives and significantly contribute to their overall health and longevity. They’re a crucial tool in managing pet health, offering protection against a myriad of diseases that can affect your pets’ quality of life and lifespan. In recent years, there’s been a rise in concerns about over-vaccination in pets and its potential to cause health complications. While these concerns are not unfounded, it’s essential to understand that vaccination decisions should be made on an individual basis. Factors like your pet’s age, health status, lifestyle, and potential exposure to diseases all play a role in determining the appropriate vaccination regimen. Consulting with a trusted veterinarian will help ensure your pets receive the necessary vaccines at the right times to keep them healthy and protected. A well-informed approach to pet vaccination is the best way to safeguard their health while mitigating any potential risks. Arming yourself with knowledge and understanding the importance of vaccines is the first step in proactive pet care. Vaccination is not merely a health measure; it’s an act of love that can add years to your pets’ lives. When it comes to vet care, the potential for side effects from vaccines can be a cause for concern among pet owners. Whilst the majority of pets will have little to no reaction to vaccinations, a small percentage may exhibit minor symptoms. These can include soreness or swelling at the injection site, reduced appetite, fever, or lethargy. These symptoms are typically short-lived, often disappearing within a day or two. In rare cases, pets may have a more serious reaction to a vaccine. Severe reactions can include persistent vomiting or diarrhea, hives, swelling of the muzzle or around the face, difficulty breathing, or collapse. If your pet shows any of these signs after receiving a vaccine, it is imperative to contact your vet immediately. Despite the small risk of side effects, it’s crucial to remember that vaccines play a pivotal role in protecting pets from life-threatening diseases. Pet vaccinations are a fundamental part of preventative care in veterinary medicine. They stimulate the immune system to produce an immune response, including the production of antibody titers that can fight off infectious agents such as the distemper virus or the rabies virus. The decision to vaccinate should always consider the potential risks and benefits. A knowledgeable vet will provide appropriate advice, taking into consideration factors such as your pet’s age, lifestyle, and overall health status. With the rise of information surrounding the risks of over-vaccination, pet owners may find themselves questioning the necessity of certain vaccines. This concern highlights the importance of a balanced and informed approach to pet vaccines. In veterinary medicine, a concept called “core vaccines” exists. These are vaccinations deemed essential for all pets, protecting against highly infectious diseases like canine parvovirus in dogs or feline calicivirus in cats. Then there are non-core vaccines, which are recommended based on a pet’s specific risk factors. Rather than adopting a one-size-fits-all approach, pet owners should engage in a discussion with their vet about the most suitable vaccination regime for their pets. Factors such as breed, age, lifestyle, and geographical location can all impact the types of vaccines needed. Moreover, the use of titer testing, which measures the level of antibodies in the pet’s blood, can help determine if booster vaccinations are needed. This can be particularly useful in avoiding unnecessary vaccinations. In conclusion, vaccines are an indispensable tool in the protection of our pets’ health. They safeguard pets from numerous, often fatal, diseases and contribute significantly to their overall well-being and longevity. The key to successful pet vaccination lies in a well-informed, individualized approach. By understanding the role of both core and non-core vaccines, being aware of potential side effects, and maintaining an open dialogue with a trusted vet, pet owners can ensure their furry friends benefit from the protective shield offered by vaccines. Remember, vaccination is not just about protecting your pets. It’s about ensuring their optimal health, enhancing their quality of life, and extending your time together. It’s more than a health measure; it’s an expression of love. So make sure to meet the team that will be caring for your pet’s health, understand the process, and make informed decisions about your pet’s vaccination regimen. After all, keeping your pet healthy is a team effort, and you are a crucial part of that team.
Today’s assignment has to do with using alternative painting methods. Did you know that painters in the past had to come up with their own paint mixtures? They didn’t have stores to go and buy paints at like we do. So, put on your renaissance hat and become a scientist as well as an artist! Please watch the video for a little more explanation: - Use hot water to dissolve candy, jello, koolaid, etc. - Use as little water as possible to create the color so the hue will be strong. You an dilute the color as needed later using a watercolor technique. - Practice on a separate sheet of paper to get used to the paint and techniques. - Do not expect perfection, be flexible with the process. - Ask your parents permission before you use any of the items above. - wet brush on dry paper - wet brush on wet paper - sprinkle wet paint with salt for added texture when dry - use a white crayon as a way to resist water color paint and keep white parts white, you must draw on the highlights first for this to work. Your assignment is to create a painting using this alternative paint that you have made. This is an experiment, I do not expect perfection. I want you to have some fun, think outside of the box and take your time creating your painting to have differences in value(shading). I don’t care what you paint as long as it has 3-dimensional form and shows shades of light and dark. Good Luck! I am excited to see what you create!
A blue planet, by Catherine Jeandel and Pascale Delecluse (book p.22f) Post: 20 June 2018 Natural, an overview over the global ocean, which covers almost three-quarter of its surface, needs an early place in a book with 133 chapters and 323 pages. The authors got the place. They raise some principle facts, including that the oceans hold a huge volume of salt water: 1.4 billion cubic meters! Its average temperature is just 2 °C. The coldest temperatures are negative, because the salt in seawater means that it does not freeze until it reaches –1.9 °C. If science talks about climate, they talk about average weather in the atmosphere. That raises immediately a principle point missing in the essay, namely that the ration between water in the air and the ocean is 1:1000, and the annual temperature difference about 15° Celsius. The sun merely heats a very thin layer of the sea surface (see images). Only a small amount of freezing cold deep-water replacing surface water, could trigger a period of low air temperatures, as for example from 1940 to the mid-.1970th, presumably due to naval warfare in WWII (see last image). Outstanding question: what sets the depth of the thermocline? Due to the fact that cold water will be denser than warm water, and salty water will be denser than less salty water, the ocean structure from top to its maximum depth of 11’020 meter, from the human perspective, seems fairly stable, but any force pushing deep water to the surface, would change the situation dramatically. The authors neglect this point. They neither raise the possible influence by man’s activities at sea that pushes sun-warmed surface water down to lower sea levels. These activities may have significantly contributed to global warming since the end of the Little Ice Age around 1850. Beside from mentioning “the ballet of the currents”, meaning the global ocean current system, within which the water takes 1000 years to complete on full lap, their major concern is the impact of carbon dioxide (CO2). To them not the oceans-make-climate, instead “the ocean also plays a role in regulating carbon dioxide in the atmosphere” (p. 23). The authors explanation goes at is follows: __ On average, human activities emit 10 gigatonnes of CO2 per year. A third of this additional gas penetrates into the ocean, is absorbed in the surface layers and therefore upsets the natural balances. __ Two balances are affected: the physico-chemical and biological CO2 pump, and the energy exchange between the air and the water, since the ocean absorbs 90% of global warming. __Climatologists are therefore fully justified in worrying about this slow accumulation of changes in our ‘blue planet’. (page 23) By this a gross limitation of the relevance of the sea in climate change matters to the carbon-dioxide issue, they lack any imagination of how the Blue Planet works. The planet is not only blue but extreme cold, where the lifeline of man is bound to an extreme thin sea surface layer, which can be changed by natural events, but also by numerous human activities at sea. Science foremost task would be to understand how much man has already induced changes in the ocean system and subsequently altered weather pattern and climate. The principle reference to CO2 is by far too little to be concerned of, which is to prevent the Blue Planet from anthropogenic global warming (AGW) and climate changes.
HTML has a set of tags that are used to present text in the form of a table. these tags are: • TABLE: marks the beginning and end of a table • TR: marks the beginning and end of a line • TH: marks the beginning and end of a cell at the top of the table • TD: marks the beginning and end of a cell • CAPTION: used to place a table with a title The code for a simple table would be: <TH> Header 1 </TH> … <TH> Header n </TH> <TD> Cell 1.1 </TD> … <TD> Cell n </TD> </TR> … <TR> <TD> Cell 1.1 </TD> … <TD> Cell n </TD> <Caption> Title </ Caption> As you can see in the code snippet the table is placed inside the TABLE tags. Every line needs be placed inside the <TR> and </TR> tags. To present separate cells we have two options: using the <TH> or <TD> tag. The difference is that the first option uses bold text and centralizes the column. Tag-u TABLE has some attributes that serve to give the table the format we need. • BORDER: determines the size of the cell contour. • CELLSPACING: determines the point size of the space between cells. • CELLPADDING: determines the distance in points between the contents of a cell and the border. • WIDTH: specifies the width of the table, can be represented by dots or percentages being of the browser. • ALIGN: position the table in relation to the page, on the left (LEFT), on the right (RIGHT) or in the center (CENTER). • BGCOLOR: determines the color of the table <TD COLSPAN=2>1.1 dhe 1.2</TD> <TD ROWSPAN=2>2.1 dhe 3.1</TD> <CAPTION ALIGN=bottom><strong><br>Tabele e Thjeshte</strong></CAPTION> <p ><strong>Tabele me ngjyra dhe imazh</strong></p> <TABLE BORDER=0 CELLSPACING=0 BGCOLOR=#0000FF> <TABLE BORDER=0 CELLSPACING=1 CELLPADDING=2 WIDTH=400 <TR> <TH><IMG SRC=”css_logo.png” height=”53″></TH> <TH>Maj</TH> <TH>Qershor</TH> <TH>Korrik</TH> <TD BGCOLOR=#A0A0A0> </TD> <TR> <TD BGCOLOR=#A0A0A0> </TD> <TD BGCOLOR=#A0A0A0> </TD> thead, tfoot, and tbody The <thead> tag is used to group the header content of an HTML table. element thead should be used together with the elements tbody and tfoot. The tbody element is used for it group body content into an HTML table and tfoot tag is used to group footer content. In a table the <tfoot> tag should appear before <tbody> so that a browser can display the footer before receiving the data of all rows. Example of using thead, tfoot, and tbody tags: <table border = “1”> <Th> Month </ th> <Th> Savings </ th> <Td> Sum </ td> <Td> $ 180 </ td> <Td> January </ td> <Td> $ 100 </ td> <Td> February </ td> <Td> $ 80 </ td> Designing the page through tables Websites are used for two reasons: 1.To organize and display information in the form of a table, when such a thing necessary. 2. To create layouts of a page using hidden tables. Using tables to divide a page into different sections is a very i tool powerful. Mainly in relation to layouts, tables are used to perform the following functions: -To split the page into different sections To create a menu, one is usually used color for the header section and another for the next line where the links are located. -To add fields of interactive forms. Example: search option. -Headers are created which are fastened. – Easier positioning of images which are divided into small pieces. – An easier way to display text in columns. Analyze a web page which has the following appearance: Forms are HTML elements that are used to obtain information from the user the form may contain input elements such as text fields, checkbox, radio-buttons, buttons submit etc. One way to create a shape is this: <FORM ACTION = “url process” METHOD = “POST”> … Elements .. Attributes of Forms: ACTION: this attribute specifies the URL where the data to be printed by the user will be sent. The action attribute indicates what happens to the data when the send button is pressed. Usually the value of attribute is a page or program on a web server that will receive and process data sent. For example, if you have a logging form that requires a username and a password; this data that the user enters will go to a login.php page and in this case the value of the action attribute i our site will be <form action = “http://www.siteJuaj.org/login.php”>. An email address can be used as a URL eg: mailto: [email protected] or an HTTP URL http://www.uamd.edu/form.html. METHOD: the method determines how the data will be sent. There are two possibilities GET and POST. The get method sends the data as part of the URL. The post method hides the data in something known as part of the HTTP header. ENCTYPE: specifies the type of coding used. The id attribute allows you to uniquely identify elements within an <form> element just as you uniquely identify an element on a page. It is good practice to specify an id element for each shape element because many shapes use style files and scripts that require the use of the id attribute in order to be done their difference. The value of the id attribute must be unique within a document. Some people put value on the id and name attribute for the form frm characters and then describe the data as e.g. of a logging form is used frmLogin or in case of a search form frmResearch etc. Attribute name (deprecated) As we have already seen the use of this attribute in other elements, the name attribute is the ancestor of the id attribute and its value must be unique throughout the document. Generally you will not see the use of the name attribute but if you will need it use ath is advised that as its value you set the value you set for the id attribute. Similar to the id attribute, it is advisable to set the frm_goal as a value in value Forms such as frmResearch or frmLogification HTML offers a wide range of elements used for input in forms. They can used for various functions such as writing text or sending files. The INPUT element is the most used and used as a field to retrieve data. there several different types of the INPUT element depending on the value that the attribute takes • TYPE = RADIO: allows you to choose from a range of options, but only one at a time. • TYPE = RESET: deletes the entire form. • TYPE: allows the user to insert a text line. • TYPE = PASSWORD: allows the user to insert a text line that appears as “*” instead of the text. It is usually used for the part where the password will be written. • TYPE = CHECKBOX: allows us to select one or more options. • TYPE = SUBMIT: takes the data entered in the form and performs the specified action • TYPE = HIDDEN: a text field that does not appear to the user. Used to store values. The INPUT element also has some optional attributes: • NAME: names the field. This is important to use in the processing code of others. • VALUE: sets an initial value to the field. SELECT is used to select one or more of the possible options. An example would to be: <SELECT name = “destination”> The attributes of the SELECT element are: • SIZE: If SIZE has a value of 1, only one of the options will appear, if the value is more more than 1 user will be shown a list of choices. • MULTIPLE: users can choose more than one option, if this is selected. The OPTION element has two attributes: • WEIGHT: the value to be assigned to the variable when this option is selected. • SELECTED: this option is selected automatically. TEXTAREA is used to get several lines of text from the user. Its format it is as follows: <TEXTAREA name = “comments” cols = 30 rows = 6> Give your impressions about our site! The content placed between <TEXTAREA> and </TEXTAREA> constitutes the initial value of this field. The attributes of TEXTAREA are: • ROWS: rows to be taken from the text box. • COLS: columns. Buttons are used in the most frequent cases to send data of a form as well as sometimes to clear data from a form. You can create buttons in three ways: Using the <input> element with the type attribute whose value is submit, reset or button. Creating the button using the <input> element When you use the <input> element for it create a button, the type of button you create is specified in the type attribute. The attribute type can take the following values to create the button: Submit, which creates a button that sends to Reset-shaped data, which creates a button that automatically empties form controls from their initialization values that are filled in when downloading the page.
One program can seat up to 99 people; larger groups will be split into two programs. Flags Over Florida Come discover the triumphs and tragedies of settling Florida’s First Coast. From Ponce de Leon to statehood, students will explore how “La Floride” became the “Sunshine State” in an interactive adventure through Florida’s history. [NGSS: SS.(4-5). A.3-4. Historical Knowledge: American History and Geography] Source-ry: What are Primary and Secondary Sources? What are primary and secondary sources? In this interactive program, students will learn the difference between these two sources and how we can use them as tools for learning and understanding the past. [NGSS: SS.(K-5). A.1. Historical Inquiry and Analysis] Guided Exhibit Tour A live tour of our latest traveling exhibit or one of our permanent exhibits. [NGSS: SS.(K-12).A.1 Historical Inquiry & Analysis]
The Solar System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, the dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly—the moons—two are larger than the smallest planet, Mercury. \|Age\|\|4.568 billion years\| \|System mass\|\|1.0014 Solar masses\| \|Nearest known planetary system\|\|Proxima Centauri system (4.25 ly)\| \|Semi-major axis of outer known planet (Neptune)\|\|30.10 AU (4.503 billion km)\| \|Distance to Kuiper cliff\|\|50 AU\| \|Known dwarf planets\| \|Known natural satellites\| \|Known minor planets\|\|796,354 (as of 2019-08-27)\| \|Known comets\|\|4,143 (as of 2019-08-27)\| \|Identified rounded satellites\|\|19 (5 or 6 likely to be in hydrostatic equilibrium)\| \|Orbit about Galactic Center\| \|Invariable-to-galactic plane inclination\|\|60.19° (ecliptic)\| \|Distance to Galactic Center\|\|27,000 ± 1,000 ly\| \|Orbital speed\|\|220 km/s\| \|Orbital period\|\|225–250 Myr\| \|Frost line\|\|≈5 AU\| \|Distance to heliopause\|\|≈120 AU\| \|Hill sphere radius\|\|≈1–3 ly\| The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All eight planets have almost circular orbits that lie within a nearly flat disc called the ecliptic. The Solar System also contains smaller objects. The asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids. Within these populations, some objects are large enough to have rounded under their own gravity, though there is considerable debate as to how many there will prove to be. Such objects are categorized as dwarf planets. Identified or accepted dwarf planets include the asteroid Ceres and the trans-Neptunian objects Pluto and Eris. In addition to these two regions, various other small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between regions. Six of the planets, the six largest possible dwarf planets, and many of the smaller bodies are orbited by natural satellites, usually termed "moons" after the Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects. The solar wind, a stream of charged particles flowing outwards from the Sun, creates a bubble-like region in the interstellar medium known as the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium; it extends out to the edge of the scattered disc. The Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The Solar System is located in the Orion Arm, 26,000 light-years from the center of the Milky Way galaxy. Discovery and exploration For most of history, humanity did not recognize or understand the concept of the Solar System. Most people up to the Late Middle Ages–Renaissance believed Earth to be stationary at the centre of the universe and categorically different from the divine or ethereal objects that moved through the sky. Although the Greek philosopher Aristarchus of Samos had speculated on a heliocentric reordering of the cosmos, Nicolaus Copernicus was the first to develop a mathematically predictive heliocentric system. In the 17th century, Galileo discovered that the Sun was marked with sunspots, and that Jupiter had four satellites in orbit around it. Christiaan Huygens followed on from Galileo's discoveries by discovering Saturn's moon Titan and the shape of the rings of Saturn. Edmond Halley realised in 1705 that repeated sightings of a comet were recording the same object, returning regularly once every 75–76 years. This was the first evidence that anything other than the planets orbited the Sun. Around this time (1704), the term "Solar System" first appeared in English. In 1838, Friedrich Bessel successfully measured a stellar parallax, an apparent shift in the position of a star created by Earth's motion around the Sun, providing the first direct, experimental proof of heliocentrism. Improvements in observational astronomy and the use of unmanned spacecraft have since enabled the detailed investigation of other bodies orbiting the Sun. Structure and composition The principal component of the Solar System is the Sun, a G2 main-sequence star that contains 99.86% of the system's known mass and dominates it gravitationally. The Sun's four largest orbiting bodies, the giant planets, account for 99% of the remaining mass, with Jupiter and Saturn together comprising more than 90%. The remaining objects of the Solar System (including the four terrestrial planets, the dwarf planets, moons, asteroids, and comets) together comprise less than 0.002% of the Solar System's total mass. Most large objects in orbit around the Sun lie near the plane of Earth's orbit, known as the ecliptic. The planets are very close to the ecliptic, whereas comets and Kuiper belt objects are frequently at significantly greater angles to it. All the planets, and most other objects, orbit the Sun in the same direction that the Sun is rotating (counter-clockwise, as viewed from above Earth's north pole). There are exceptions, such as Halley's Comet. The overall structure of the charted regions of the Solar System consists of the Sun, four relatively small inner planets surrounded by a belt of mostly rocky asteroids, and four giant planets surrounded by the Kuiper belt of mostly icy objects. Astronomers sometimes informally divide this structure into separate regions. The inner Solar System includes the four terrestrial planets and the asteroid belt. The outer Solar System is beyond the asteroids, including the four giant planets. Since the discovery of the Kuiper belt, the outermost parts of the Solar System are considered a distinct region consisting of the objects beyond Neptune. Most of the planets in the Solar System have secondary systems of their own, being orbited by planetary objects called natural satellites, or moons (two of which, Titan and Ganymede, are larger than the planet Mercury), and, in the case of the four giant planets, by planetary rings, thin bands of tiny particles that orbit them in unison. Most of the largest natural satellites are in synchronous rotation, with one face permanently turned toward their parent. Kepler's laws of planetary motion describe the orbits of objects about the Sun. Following Kepler's laws, each object travels along an ellipse with the Sun at one focus. Objects closer to the Sun (with smaller semi-major axes) travel more quickly because they are more affected by the Sun's gravity. On an elliptical orbit, a body's distance from the Sun varies over the course of its year. A body's closest approach to the Sun is called its perihelion, whereas its most distant point from the Sun is called its aphelion. The orbits of the planets are nearly circular, but many comets, asteroids, and Kuiper belt objects follow highly elliptical orbits. The positions of the bodies in the Solar System can be predicted using numerical models. Although the Sun dominates the system by mass, it accounts for only about 2% of the angular momentum. The planets, dominated by Jupiter, account for most of the rest of the angular momentum due to the combination of their mass, orbit, and distance from the Sun, with a possibly significant contribution from comets. The Sun, which comprises nearly all the matter in the Solar System, is composed of roughly 98% hydrogen and helium. Jupiter and Saturn, which comprise nearly all the remaining matter, are also primarily composed of hydrogen and helium. A composition gradient exists in the Solar System, created by heat and light pressure from the Sun; those objects closer to the Sun, which are more affected by heat and light pressure, are composed of elements with high melting points. Objects farther from the Sun are composed largely of materials with lower melting points. The boundary in the Solar System beyond which those volatile substances could condense is known as the frost line, and it lies at roughly 5 AU from the Sun. The objects of the inner Solar System are composed mostly of rock, the collective name for compounds with high melting points, such as silicates, iron or nickel, that remained solid under almost all conditions in the protoplanetary nebula. Jupiter and Saturn are composed mainly of gases, the astronomical term for materials with extremely low melting points and high vapour pressure, such as hydrogen, helium, and neon, which were always in the gaseous phase in the nebula. Ices, like water, methane, ammonia, hydrogen sulfide, and carbon dioxide, have melting points up to a few hundred kelvins. They can be found as ices, liquids, or gases in various places in the Solar System, whereas in the nebula they were either in the solid or gaseous phase. Icy substances comprise the majority of the satellites of the giant planets, as well as most of Uranus and Neptune (the so-called "ice giants") and the numerous small objects that lie beyond Neptune's orbit. Together, gases and ices are referred to as volatiles. Distances and scales The distance from Earth to the Sun is 1 astronomical unit [AU] (150,000,000 km; 93,000,000 mi). For comparison, the radius of the Sun is 0.0047 AU (700,000 km). Thus, the Sun occupies 0.00001% (10−5 %) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly one millionth (10−6) that of the Sun. Jupiter, the largest planet, is 5.2 astronomical units (780,000,000 km) from the Sun and has a radius of 71,000 km (0.00047 AU), whereas the most distant planet, Neptune, is 30 AU (4.5×109 km) from the Sun. With a few exceptions, the farther a planet or belt is from the Sun, the larger the distance between its orbit and the orbit of the next nearer object to the Sun. For example, Venus is approximately 0.33 AU farther out from the Sun than Mercury, whereas Saturn is 4.3 AU out from Jupiter, and Neptune lies 10.5 AU out from Uranus. Attempts have been made to determine a relationship between these orbital distances (for example, the Titius–Bode law), but no such theory has been accepted. The images at the beginning of this section show the orbits of the various constituents of the Solar System on different scales. Some Solar System models attempt to convey the relative scales involved in the Solar System on human terms. Some are small in scale (and may be mechanical—called orreries)—whereas others extend across cities or regional areas. The largest such scale model, the Sweden Solar System, uses the 110-metre (361 ft) Ericsson Globe in Stockholm as its substitute Sun, and, following the scale, Jupiter is a 7.5-metre (25-foot) sphere at Stockholm Arlanda Airport, 40 km (25 mi) away, whereas the farthest current object, Sedna, is a 10 cm (4 in) sphere in Luleå, 912 km (567 mi) away. If the Sun–Neptune distance is scaled to 100 metres, then the Sun would be about 3 cm in diameter (roughly two-thirds the diameter of a golf ball), the giant planets would be all smaller than about 3 mm, and Earth's diameter along with that of the other terrestrial planets would be smaller than a flea (0.3 mm) at this scale. Formation and evolution The Solar System formed 4.568 billion years ago from the gravitational collapse of a region within a large molecular cloud. This initial cloud was likely several light-years across and probably birthed several stars. As is typical of molecular clouds, this one consisted mostly of hydrogen, with some helium, and small amounts of heavier elements fused by previous generations of stars. As the region that would become the Solar System, known as the pre-solar nebula, collapsed, conservation of angular momentum caused it to rotate faster. The centre, where most of the mass collected, became increasingly hotter than the surrounding disc. As the contracting nebula rotated faster, it began to flatten into a protoplanetary disc with a diameter of roughly 200 AU and a hot, dense protostar at the centre. The planets formed by accretion from this disc, in which dust and gas gravitationally attracted each other, coalescing to form ever larger bodies. Hundreds of protoplanets may have existed in the early Solar System, but they either merged or were destroyed, leaving the planets, dwarf planets, and leftover minor bodies. Due to their higher boiling points, only metals and silicates could exist in solid form in the warm inner Solar System close to the Sun, and these would eventually form the rocky planets of Mercury, Venus, Earth, and Mars. Because metallic elements only comprised a very small fraction of the solar nebula, the terrestrial planets could not grow very large. The giant planets (Jupiter, Saturn, Uranus, and Neptune) formed further out, beyond the frost line, the point between the orbits of Mars and Jupiter where material is cool enough for volatile icy compounds to remain solid. The ices that formed these planets were more plentiful than the metals and silicates that formed the terrestrial inner planets, allowing them to grow massive enough to capture large atmospheres of hydrogen and helium, the lightest and most abundant elements. Leftover debris that never became planets congregated in regions such as the asteroid belt, Kuiper belt, and Oort cloud. The Nice model is an explanation for the creation of these regions and how the outer planets could have formed in different positions and migrated to their current orbits through various gravitational interactions. Within 50 million years, the pressure and density of hydrogen in the centre of the protostar became great enough for it to begin thermonuclear fusion. The temperature, reaction rate, pressure, and density increased until hydrostatic equilibrium was achieved: the thermal pressure equalled the force of gravity. At this point, the Sun became a main-sequence star. The main-sequence phase, from beginning to end, will last about 10 billion years for the Sun compared to around two billion years for all other phases of the Sun's pre-remnant life combined. Solar wind from the Sun created the heliosphere and swept away the remaining gas and dust from the protoplanetary disc into interstellar space, ending the planetary formation process. The Sun is growing brighter; early in its main-sequence life its brightness was 70% that of what it is today. The Solar System will remain roughly as we know it today until the hydrogen in the core of the Sun has been entirely converted to helium, which will occur roughly 5 billion years from now. This will mark the end of the Sun's main-sequence life. At this time, the core of the Sun will contract with hydrogen fusion occurring along a shell surrounding the inert helium, and the energy output will be much greater than at present. The outer layers of the Sun will expand to roughly 260 times its current diameter, and the Sun will become a red giant. Because of its vastly increased surface area, the surface of the Sun will be considerably cooler (2,600 K at its coolest) than it is on the main sequence. The expanding Sun is expected to vaporize Mercury and render Earth uninhabitable. Eventually, the core will be hot enough for helium fusion; the Sun will burn helium for a fraction of the time it burned hydrogen in the core. The Sun is not massive enough to commence the fusion of heavier elements, and nuclear reactions in the core will dwindle. Its outer layers will move away into space, leaving a white dwarf, an extraordinarily dense object, half the original mass of the Sun but only the size of Earth. The ejected outer layers will form what is known as a planetary nebula, returning some of the material that formed the Sun—but now enriched with heavier elements like carbon—to the interstellar medium. The Sun is the Solar System's star and by far its most massive component. Its large mass (332,900 Earth masses), which comprises 99.86% of all the mass in the Solar System, produces temperatures and densities in its core high enough to sustain nuclear fusion of hydrogen into helium, making it a main-sequence star. This releases an enormous amount of energy, mostly radiated into space as electromagnetic radiation peaking in visible light. The Sun is a G2-type main-sequence star. Hotter main-sequence stars are more luminous. The Sun's temperature is intermediate between that of the hottest stars and that of the coolest stars. Stars brighter and hotter than the Sun are rare, whereas substantially dimmer and cooler stars, known as red dwarfs, make up 85% of the stars in the Milky Way. The Sun is a population I star; it has a higher abundance of elements heavier than hydrogen and helium ("metals" in astronomical parlance) than the older population II stars. Elements heavier than hydrogen and helium were formed in the cores of ancient and exploding stars, so the first generation of stars had to die before the Universe could be enriched with these atoms. The oldest stars contain few metals, whereas stars born later have more. This high metallicity is thought to have been crucial to the Sun's development of a planetary system because the planets form from the accretion of "metals". The vast majority of the Solar System consists of a near-vacuum known as the interplanetary medium. Along with light, the Sun radiates a continuous stream of charged particles (a plasma) known as the solar wind. This stream of particles spreads outwards at roughly 1.5 million kilometres per hour, creating a tenuous atmosphere that permeates the interplanetary medium out to at least 100 AU (see § Heliosphere). Activity on the Sun's surface, such as solar flares and coronal mass ejections, disturbs the heliosphere, creating space weather and causing geomagnetic storms. The largest structure within the heliosphere is the heliospheric current sheet, a spiral form created by the actions of the Sun's rotating magnetic field on the interplanetary medium. Earth's magnetic field stops its atmosphere from being stripped away by the solar wind. Venus and Mars do not have magnetic fields, and as a result the solar wind is causing their atmospheres to gradually bleed away into space. Coronal mass ejections and similar events blow a magnetic field and huge quantities of material from the surface of the Sun. The interaction of this magnetic field and material with Earth's magnetic field funnels charged particles into Earth's upper atmosphere, where its interactions create aurorae seen near the magnetic poles. The heliosphere and planetary magnetic fields (for those planets that have them) partially shield the Solar System from high-energy interstellar particles called cosmic rays. The density of cosmic rays in the interstellar medium and the strength of the Sun's magnetic field change on very long timescales, so the level of cosmic-ray penetration in the Solar System varies, though by how much is unknown. The interplanetary medium is home to at least two disc-like regions of cosmic dust. The first, the zodiacal dust cloud, lies in the inner Solar System and causes the zodiacal light. It was likely formed by collisions within the asteroid belt brought on by gravitational interactions with the planets. The second dust cloud extends from about 10 AU to about 40 AU, and was probably created by similar collisions within the Kuiper belt. Inner Solar System The inner Solar System is the region comprising the terrestrial planets and the asteroid belt. Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is less than the distance between the orbits of Jupiter and Saturn. This region is also within the frost line, which is a little less than 5 AU (about 700 million km) from the Sun. The four terrestrial or inner planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates—which form their crusts and mantles—and metals, such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features, such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets that are closer to the Sun than Earth is (i.e. Mercury and Venus). Mercury (0.4 AU from the Sun) is the closest planet to the Sun and on average, all seven other planets. The smallest planet in the Solar System (0.055 M⊕), Mercury has no natural satellites. Besides impact craters, its only known geological features are lobed ridges or rupes that were probably produced by a period of contraction early in its history. Mercury's very tenuous atmosphere consists of atoms blasted off its surface by the solar wind. Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, or that it was prevented from fully accreting by the young Sun's energy. Venus (0.7 AU from the Sun) is close in size to Earth (0.815 M⊕) and, like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere, and evidence of internal geological activity. It is much drier than Earth, and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C (752 °F), most likely due to the amount of greenhouse gases in the atmosphere. No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is being replenished by volcanic eruptions. Earth (1 AU from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and the only place where life is known to exist. Its liquid hydrosphere is unique among the terrestrial planets, and it is the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen. It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System. Mars (1.5 AU from the Sun) is smaller than Earth and Venus (0.107 M⊕). It has an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (roughly 0.6% of that of Earth). Its surface, peppered with vast volcanoes, such as Olympus Mons, and rift valleys, such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago. Its red colour comes from iron oxide (rust) in its soil. Mars has two tiny natural satellites (Deimos and Phobos) thought to be either captured asteroids, or ejected debris from a massive impact early in Mars's history. Asteroids except for the largest, Ceres, are classified as small Solar System bodies and are composed mainly of refractory rocky and metallic minerals, with some ice. They range from a few metres to hundreds of kilometres in size. Asteroids smaller than one meter are usually called meteoroids and micrometeoroids (grain-sized), depending on different, somewhat arbitrary definitions. The asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter. The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter. Despite this, the total mass of the asteroid belt is unlikely to be more than a thousandth of that of Earth. The asteroid belt is very sparsely populated; spacecraft routinely pass through without incident. Ceres (2.77 AU) is the largest asteroid, a protoplanet, and a dwarf planet. It has a diameter of slightly under 1000 km, and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in 1801, and was reclassified to asteroid in the 1850s as further observations revealed additional asteroids. It was classified as a dwarf planet in 2006 when the definition of a planet was created. Asteroids in the asteroid belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets, which may have been the source of Earth's water. Jupiter trojans are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term trojan is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits. Outer Solar System The outer region of the Solar System is home to the giant planets and their large moons. The centaurs and many short-period comets also orbit in this region. Due to their greater distance from the Sun, the solid objects in the outer Solar System contain a higher proportion of volatiles, such as water, ammonia, and methane than those of the inner Solar System because the lower temperatures allow these compounds to remain solid. The four outer planets, or giant planets (sometimes called Jovian planets), collectively make up 99% of the mass known to orbit the Sun. Jupiter and Saturn are together more than 400 times the mass of Earth and consist overwhelmingly of hydrogen and helium. Uranus and Neptune are far less massive—less than 20 Earth masses (M⊕) each—and are composed primarily of ices. For these reasons, some astronomers suggest they belong in their own category, ice giants. All four giant planets have rings, although only Saturn's ring system is easily observed from Earth. The term superior planet designates planets outside Earth's orbit and thus includes both the outer planets and Mars. Jupiter (5.2 AU), at 318 M⊕, is 2.5 times the mass of all the other planets put together. It is composed largely of hydrogen and helium. Jupiter's strong internal heat creates semi-permanent features in its atmosphere, such as cloud bands and the Great Red Spot. Jupiter has 79 known satellites. The four largest, Ganymede, Callisto, Io, and Europa, show similarities to the terrestrial planets, such as volcanism and internal heating. Ganymede, the largest satellite in the Solar System, is larger than Mercury. Saturn (9.5 AU), distinguished by its extensive ring system, has several similarities to Jupiter, such as its atmospheric composition and magnetosphere. Although Saturn has 60% of Jupiter's volume, it is less than a third as massive, at 95 M⊕. Saturn is the only planet of the Solar System that is less dense than water. The rings of Saturn are made up of small ice and rock particles. Saturn has 82 confirmed satellites composed largely of ice. Two of these, Titan and Enceladus, show signs of geological activity. Titan, the second-largest moon in the Solar System, is larger than Mercury and the only satellite in the Solar System with a substantial atmosphere. Uranus (19.2 AU), at 14 M⊕, is the lightest of the outer planets. Uniquely among the planets, it orbits the Sun on its side; its axial tilt is over ninety degrees to the ecliptic. It has a much colder core than the other giant planets and radiates very little heat into space. Uranus has 27 known satellites, the largest ones being Titania, Oberon, Umbriel, Ariel, and Miranda. Neptune (30.1 AU), though slightly smaller than Uranus, is more massive (17 M⊕) and hence more dense. It radiates more internal heat, but not as much as Jupiter or Saturn. Neptune has 14 known satellites. The largest, Triton, is geologically active, with geysers of liquid nitrogen. Triton is the only large satellite with a retrograde orbit. Neptune is accompanied in its orbit by several minor planets, termed Neptune trojans, that are in 1:1 resonance with it. The centaurs are icy comet-like bodies whose orbits have semi-major axes greater than Jupiter's (5.5 AU) and less than Neptune's (30 AU). The largest known centaur, 10199 Chariklo, has a diameter of about 250 km. The first centaur discovered, 2060 Chiron, has also been classified as comet (95P) because it develops a coma just as comets do when they approach the Sun. Comets are small Solar System bodies, typically only a few kilometres across, composed largely of volatile ices. They have highly eccentric orbits, generally a perihelion within the orbits of the inner planets and an aphelion far beyond Pluto. When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionise, creating a coma: a long tail of gas and dust often visible to the naked eye. Short-period comets have orbits lasting less than two hundred years. Long-period comets have orbits lasting thousands of years. Short-period comets are thought to originate in the Kuiper belt, whereas long-period comets, such as Hale–Bopp, are thought to originate in the Oort cloud. Many comet groups, such as the Kreutz Sungrazers, formed from the breakup of a single parent. Some comets with hyperbolic orbits may originate outside the Solar System, but determining their precise orbits is difficult. Old comets that have had most of their volatiles driven out by solar warming are often categorised as asteroids. Beyond the orbit of Neptune lies the area of the "trans-Neptunian region", with the doughnut-shaped Kuiper belt, home of Pluto and several other dwarf planets, and an overlapping disc of scattered objects, which is tilted toward the plane of the Solar System and reaches much further out than the Kuiper belt. The entire region is still largely unexplored. It appears to consist overwhelmingly of many thousands of small worlds—the largest having a diameter only a fifth that of Earth and a mass far smaller than that of the Moon—composed mainly of rock and ice. This region is sometimes described as the "third zone of the Solar System", enclosing the inner and the outer Solar System. The Kuiper belt is a great ring of debris similar to the asteroid belt, but consisting mainly of objects composed primarily of ice. It extends between 30 and 50 AU from the Sun. Though it is estimated to contain anything from dozens to thousands of dwarf planets, it is composed mainly of small Solar System bodies. Many of the larger Kuiper belt objects, such as Quaoar, Varuna, and Orcus, may prove to be dwarf planets with further data. There are estimated to be over 100,000 Kuiper belt objects with a diameter greater than 50 km, but the total mass of the Kuiper belt is thought to be only a tenth or even a hundredth the mass of Earth. Many Kuiper belt objects have multiple satellites, and most have orbits that take them outside the plane of the ecliptic. The Kuiper belt can be roughly divided into the "classical" belt and the resonances. Resonances are orbits linked to that of Neptune (e.g. twice for every three Neptune orbits, or once for every two). The first resonance begins within the orbit of Neptune itself. The classical belt consists of objects having no resonance with Neptune, and extends from roughly 39.4 AU to 47.7 AU. Members of the classical Kuiper belt are classified as cubewanos, after the first of their kind to be discovered, 15760 Albion (which previously had the provisional designation 1992 QB1), and are still in near primordial, low-eccentricity orbits. Pluto and Charon The dwarf planet Pluto (39 AU average) is the largest known object in the Kuiper belt. When discovered in 1930, it was considered to be the ninth planet; this changed in 2006 with the adoption of a formal definition of planet. Pluto has a relatively eccentric orbit inclined 17 degrees to the ecliptic plane and ranging from 29.7 AU from the Sun at perihelion (within the orbit of Neptune) to 49.5 AU at aphelion. Pluto has a 3:2 resonance with Neptune, meaning that Pluto orbits twice round the Sun for every three Neptunian orbits. Kuiper belt objects whose orbits share this resonance are called plutinos. Charon, the largest of Pluto's moons, is sometimes described as part of a binary system with Pluto, as the two bodies orbit a barycentre of gravity above their surfaces (i.e. they appear to "orbit each other"). Beyond Charon, four much smaller moons, Styx, Nix, Kerberos, and Hydra, orbit within the system. Makemake and Haumea Makemake (45.79 AU average), although smaller than Pluto, is the largest known object in the classical Kuiper belt (that is, a Kuiper belt object not in a confirmed resonance with Neptune). Makemake is the brightest object in the Kuiper belt after Pluto. It was assigned a naming committee under the expectation that it would prove to be a dwarf planet in 2008. Its orbit is far more inclined than Pluto's, at 29°. Haumea (43.13 AU average) is in an orbit similar to Makemake, except that it is in a temporary 7:12 orbital resonance with Neptune. It was named under the same expectation that it would prove to be a dwarf planet, though subsequent observations have indicated that it may not be a dwarf planet after all. The scattered disc, which overlaps the Kuiper belt but extends out to about 200 AU, is thought to be the source of short-period comets. Scattered-disc objects are thought to have been ejected into erratic orbits by the gravitational influence of Neptune's early outward migration. Most scattered disc objects (SDOs) have perihelia within the Kuiper belt but aphelia far beyond it (some more than 150 AU from the Sun). SDOs' orbits are also highly inclined to the ecliptic plane and are often almost perpendicular to it. Some astronomers consider the scattered disc to be merely another region of the Kuiper belt and describe scattered disc objects as "scattered Kuiper belt objects". Some astronomers also classify centaurs as inward-scattered Kuiper belt objects along with the outward-scattered residents of the scattered disc. Eris (68 AU average) is the largest known scattered disc object, and caused a debate about what constitutes a planet, because it is 25% more massive than Pluto and about the same diameter. It is the most massive of the known dwarf planets. It has one known moon, Dysnomia. Like Pluto, its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and steeply inclined to the ecliptic plane. 2007 OR10 (67.4 AU average) is the second-largest scattered disc object and the largest object in the Solar System without an official name. It is fifth largest and fifth most massive trans-Neptunian object after Pluto, Eris, Haumea and Makemake. Similarly to Eris, its orbit is highly eccentric and steeply inclined to the ecliptic plane. It is a quite possibly a dwarf planet. The point at which the Solar System ends and interstellar space begins is not precisely defined because its outer boundaries are shaped by two separate forces: the solar wind and the Sun's gravity. The limit of the solar wind's influence is roughly four times Pluto's distance from the Sun; this heliopause, the outer boundary of the heliosphere, is considered the beginning of the interstellar medium. The Sun's Hill sphere, the effective range of its gravitational dominance, is thought to extend up to a thousand times farther and encompasses the theorized Oort cloud. The heliosphere is a stellar-wind bubble, a region of space dominated by the Sun, which radiates at roughly 400 km/s its solar wind, a stream of charged particles, until it collides with the wind of the interstellar medium. The collision occurs at the termination shock, which is roughly 80–100 AU from the Sun upwind of the interstellar medium and roughly 200 AU from the Sun downwind. Here the wind slows dramatically, condenses and becomes more turbulent, forming a great oval structure known as the heliosheath. This structure is thought to look and behave very much like a comet's tail, extending outward for a further 40 AU on the upwind side but tailing many times that distance downwind; evidence from Cassini and Interstellar Boundary Explorer spacecraft has suggested that it is forced into a bubble shape by the constraining action of the interstellar magnetic field. The outer boundary of the heliosphere, the heliopause, is the point at which the solar wind finally terminates and is the beginning of interstellar space. Voyager 1 and Voyager 2 are reported to have passed the termination shock and entered the heliosheath, at 94 and 84 AU from the Sun, respectively. Voyager 1 is reported to have crossed the heliopause in August 2012. The shape and form of the outer edge of the heliosphere is likely affected by the fluid dynamics of interactions with the interstellar medium as well as solar magnetic fields prevailing to the south, e.g. it is bluntly shaped with the northern hemisphere extending 9 AU farther than the southern hemisphere. Beyond the heliopause, at around 230 AU, lies the bow shock, a plasma "wake" left by the Sun as it travels through the Milky Way. Due to a lack of data, conditions in local interstellar space are not known for certain. It is expected that NASA's Voyager spacecraft, as they pass the heliopause, will transmit valuable data on radiation levels and solar wind to Earth. How well the heliosphere shields the Solar System from cosmic rays is poorly understood. A NASA-funded team has developed a concept of a "Vision Mission" dedicated to sending a probe to the heliosphere. 90377 Sedna (520 AU average) is a large, reddish object with a gigantic, highly elliptical orbit that takes it from about 76 AU at perihelion to 940 AU at aphelion and takes 11,400 years to complete. Mike Brown, who discovered the object in 2003, asserts that it cannot be part of the scattered disc or the Kuiper belt because its perihelion is too distant to have been affected by Neptune's migration. He and other astronomers consider it to be the first in an entirely new population, sometimes termed "distant detached objects" (DDOs), which also may include the object 2000 CR105, which has a perihelion of 45 AU, an aphelion of 415 AU, and an orbital period of 3,420 years. Brown terms this population the "inner Oort cloud" because it may have formed through a similar process, although it is far closer to the Sun. Sedna is very likely a dwarf planet, though its shape has yet to be determined. The second unequivocally detached object, with a perihelion farther than Sedna's at roughly 81 AU, is 2012 VP113, discovered in 2012. Its aphelion is only half that of Sedna's, at 400–500 AU. The Oort cloud is a hypothetical spherical cloud of up to a trillion icy objects that is thought to be the source for all long-period comets and to surround the Solar System at roughly 50,000 AU (around 1 light-year (ly)), and possibly to as far as 100,000 AU (1.87 ly). It is thought to be composed of comets that were ejected from the inner Solar System by gravitational interactions with the outer planets. Oort cloud objects move very slowly, and can be perturbed by infrequent events, such as collisions, the gravitational effects of a passing star, or the galactic tide, the tidal force exerted by the Milky Way. Much of the Solar System is still unknown. The Sun's gravitational field is estimated to dominate the gravitational forces of surrounding stars out to about two light years (125,000 AU). Lower estimates for the radius of the Oort cloud, by contrast, do not place it farther than 50,000 AU. Despite discoveries such as Sedna, the region between the Kuiper belt and the Oort cloud, an area tens of thousands of AU in radius, is still virtually unmapped. There are also ongoing studies of the region between Mercury and the Sun. Objects may yet be discovered in the Solar System's uncharted regions. Currently, the furthest known objects, such as Comet West, have aphelia around 70,000 AU from the Sun, but as the Oort cloud becomes better known, this may change. The Solar System is located in the Milky Way, a barred spiral galaxy with a diameter of about 100,000 light-years containing more than 100 billion stars. The Sun resides in one of the Milky Way's outer spiral arms, known as the Orion–Cygnus Arm or Local Spur. The Sun lies between 25,000 and 28,000 light-years from the Galactic Centre, and its speed within the Milky Way is about 220 km/s, so that it completes one revolution every 225–250 million years. This revolution is known as the Solar System's galactic year. The solar apex, the direction of the Sun's path through interstellar space, is near the constellation Hercules in the direction of the current location of the bright star Vega. The plane of the ecliptic lies at an angle of about 60° to the galactic plane. The Solar System's location in the Milky Way is a factor in the evolutionary history of life on Earth. Its orbit is close to circular, and orbits near the Sun are at roughly the same speed as that of the spiral arms. Therefore, the Sun passes through arms only rarely. Because spiral arms are home to a far larger concentration of supernovae, gravitational instabilities, and radiation that could disrupt the Solar System, this has given Earth long periods of stability for life to evolve. The Solar System also lies well outside the star-crowded environs of the galactic centre. Near the centre, gravitational tugs from nearby stars could perturb bodies in the Oort cloud and send many comets into the inner Solar System, producing collisions with potentially catastrophic implications for life on Earth. The intense radiation of the galactic centre could also interfere with the development of complex life. Even at the Solar System's current location, some scientists have speculated that recent supernovae may have adversely affected life in the last 35,000 years, by flinging pieces of expelled stellar core towards the Sun, as radioactive dust grains and larger, comet-like bodies. The Solar System is in the Local Interstellar Cloud or Local Fluff. It is thought to be near the neighbouring G-Cloud but it is not known if the Solar System is embedded in the Local Interstellar Cloud, or if it is in the region where the Local Interstellar Cloud and G-Cloud are interacting. The Local Interstellar Cloud is an area of denser cloud in an otherwise sparse region known as the Local Bubble, an hourglass-shaped cavity in the interstellar medium roughly 300 light-years (ly) across. The bubble is suffused with high-temperature plasma, that suggests it is the product of several recent supernovae. There are relatively few stars within ten light-years of the Sun. The closest is the triple star system Alpha Centauri, which is about 4.4 light-years away. Alpha Centauri A and B are a closely tied pair of Sun-like stars, whereas the small red dwarf, Proxima Centauri, orbits the pair at a distance of 0.2 light-year. In 2016, a potentially habitable exoplanet was confirmed to be orbiting Proxima Centauri, called Proxima Centauri b, the closest confirmed exoplanet to the Sun. The stars next closest to the Sun are the red dwarfs Barnard's Star (at 5.9 ly), Wolf 359 (7.8 ly), and Lalande 21185 (8.3 ly). The largest nearby star is Sirius, a bright main-sequence star roughly 8.6 light-years away and roughly twice the Sun's mass and that is orbited by a white dwarf, Sirius B. The nearest brown dwarfs are the binary Luhman 16 system at 6.6 light-years. Other systems within ten light-years are the binary red-dwarf system Luyten 726-8 (8.7 ly) and the solitary red dwarf Ross 154 (9.7 ly). The closest solitary Sun-like star to the Solar System is Tau Ceti at 11.9 light-years. It has roughly 80% of the Sun's mass but only 60% of its luminosity. The closest known free-floating planetary-mass object to the Sun is WISE 0855−0714, an object with a mass less than 10 Jupiter masses roughly 7 light-years away. Comparison with extrasolar systems Compared to many other planetary systems, the Solar System stands out in lacking planets interior to the orbit of Mercury. The known Solar System also lacks super-Earths (Planet Nine could be a super-Earth beyond the known Solar System). Uncommonly, it has only small rocky planets and large gas giants; elsewhere planets of intermediate size are typical—both rocky and gas—so there is no "gap" as seen between the size of Earth and of Neptune (with a radius 3.8 times as large). Also, these super-Earths have closer orbits than Mercury. This led to the hypothesis that all planetary systems start with many close-in planets, and that typically a sequence of their collisions causes consolidation of mass into few larger planets, but in case of the Solar System the collisions caused their destruction and ejection. The orbits of Solar System planets are nearly circular. Compared to other systems, they have smaller orbital eccentricity. Although there are attempts to explain it partly with a bias in the radial-velocity detection method and partly with long interactions of a quite high number of planets, the exact causes remain undetermined. This section is a sampling of Solar System bodies, selected for size and quality of imagery, and sorted by volume. Some omitted objects are larger than the ones included here, notably Eris, because these have not been imaged in high quality. (moon of Jupiter) (moon of Saturn) (moon of Jupiter) (moon of Jupiter) (moon of Earth) (moon of Jupiter) (moon of Neptune) (Kuiper belt object) (moon of Uranus) (moon of Saturn) (moon of Uranus) (moon of Saturn) (moon of Pluto) (moon of Uranus) (moon of Uranus) (moon of Saturn) (moon of Saturn) (moon of Saturn) (moon of Uranus) (moon of Neptune) (moon of Saturn) (moon of Saturn) (moon of Saturn) (moon of Saturn) (moon of Saturn) (moon of Saturn) (moon of Saturn) (moon of Saturn) (Kuiper Belt object) (moon of Mars) (moon of Mars) \|Voyager 1 views the Solar System from over 6 billion km from Earth.\| - Astronomical symbols - Earth phase - Ephemeris is a compilation of positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times. - HIP 11915 (a solar analog whose planets contains a Jupiter analog) - Lists of geological features of the Solar System - List of gravitationally rounded objects of the Solar System - List of Solar System extremes - List of Solar System objects by size - Outline of the Solar System - Planetary mnemonic - Solar System in fiction - Solar System models - Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects, but uses mixed "Solar System" and "solar system" in their naming guidelines document. The name is commonly rendered in lower case ("solar system"), as, for example, in the Oxford English Dictionary and Merriam-Webster's 11th Collegiate Dictionary. - The natural satellites (moons) orbiting the Solar System's planets are an example of the latter. - Historically, several other bodies were once considered planets, including, from its discovery in 1930 until 2006, Pluto. See Former planets. - The two moons larger than Mercury are Ganymede, which orbits Jupiter, and Titan, which orbits Saturn. Although bigger than Mercury, both moons have less than half its mass. In addition, the radius of Jupiter's moon Callisto is over 98% that of Mercury. - According to IAU definitions, objects orbiting the Sun are classified dynamically and physically into three categories: planets, dwarf planets, and small Solar System bodies. - A planet is any body orbiting the Sun whose mass is sufficient for gravity to have pulled it into a (near-)spherical shape and that has cleared its immediate neighbourhood of all smaller objects. By this definition, the Solar System has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Because it has not cleared its neighbourhood of other Kuiper belt objects, Pluto does not fit this definition. - A dwarf planet is a body orbiting the Sun that is massive enough to be made near-spherical by its own gravity but that has not cleared planetesimals from its neighbourhood and is also not a satellite. Pluto is a dwarf planet and the IAU has recognized or named four other bodies in the Solar System under the expectation that they will turn out to be dwarf planets: Ceres, Haumea, Makemake, and Eris. Other objects commonly expected to be dwarf planets include 2007 OR10, Sedna, Orcus, and Quaoar. In a reference to Pluto, other dwarf planets orbiting in the trans-Neptunian region are sometimes called "plutoids", though this term is seldom used. - The remaining objects orbiting the Sun are known as small Solar System bodies. - See List of natural satellites of the Solar System for the full list of natural satellites of the eight planets and largest possible dwarf planets - The mass of the Solar System excluding the Sun, Jupiter and Saturn can be determined by adding together all the calculated masses for its largest objects and using rough calculations for the masses of the Oort cloud (estimated at roughly 3 Earth masses), the Kuiper belt (estimated at roughly 0.1 Earth mass) and the asteroid belt (estimated to be 0.0005 Earth mass) for a total, rounded upwards, of ~37 Earth masses, or 8.1% of the mass in orbit around the Sun. With the combined masses of Uranus and Neptune (~31 Earth masses) subtracted, the remaining ~6 Earth masses of material comprise 1.3% of the total orbiting mass. - The date is based on the oldest inclusions found to date in meteorites, 4568.2+0.2 −0.4 million years, and is thought to be the date of the formation of the first solid material in the collapsing nebula. - If is the angle between the north pole of the ecliptic and the north galactic pole then: where = 27° 07′ 42.01″ and = 12h 51m 26.282 are the declination and right ascension of the north galactic pole, whereas = 66° 33′ 38.6″ and = 18h 0m 00 are those for the north pole of the ecliptic. (Both pairs of coordinates are for J2000 epoch.) The result of the calculation is 60.19°. - "How Many Solar System Bodies". NASA/JPL Solar System Dynamics. Retrieved 20 April 2018. - Wm. Robert Johnston (15 September 2019). "Asteroids with Satellites". Johnston's Archive. Retrieved 28 September 2019. - "Latest Published Data". The International Astronomical Union Minor Planet Center. Retrieved 28 September 2019. - Mumma, M.J.; Disanti, M.A.; Dello Russo, N.; Magee-Sauer, K.; Gibb, E.; Novak, R. (2003). "Remote infrared observations of parent volatiles in comets: A window on the early solar system". Advances in Space Research. 31 (12): 2563–2575. Bibcode:2003AdSpR..31.2563M. CiteSeerX 10.1.1.575.5091. doi:10.1016/S0273-1177(03)00578-7. - "The Final IAU Resolution on the definition of "planet" ready for voting". IAU. 24 August 2006. Archived from the original on 7 January 2009. Retrieved 2 March 2007. - "Dwarf Planets and their Systems". Working Group for Planetary System Nomenclature (WGPSN). U.S. Geological Survey. 7 November 2008. Retrieved 13 July 2008. - Ron Ekers. "IAU Planet Definition Committee". International Astronomical Union. Archived from the original on 3 June 2009. Retrieved 13 October 2008. - "Plutoid chosen as name for Solar System objects like Pluto". International Astronomical Union, Paris. 11 June 2008. Archived from the original on 13 June 2008. Retrieved 11 June 2008. - Grundy, W.M.; Noll, K.S.; Buie, M.W.; Benecchi, S.D.; Ragozzine, D.; Roe, H.G. (December 2018). "The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK126)" (PDF). Icarus. doi:10.1016/j.icarus.2018.12.037. Archived from the original on 7 April 2019. - Mike Brown (23 August 2011). "Free the dwarf planets!". Mike Brown's Planets. - WC Rufus (1923). "The astronomical system of Copernicus". Popular Astronomy. Vol. 31. p. 510. Bibcode:1923PA.....31..510R. - Weinert, Friedel (2009). Copernicus, Darwin, & Freud: revolutions in the history and philosophy of science. Wiley-Blackwell. p. 21. ISBN 978-1-4051-8183-9. - Eric W. Weisstein (2006). "Galileo Galilei (1564–1642)". Wolfram Research. Retrieved 27 October 2010. - "Discoverer of Titan: Christiaan Huygens". ESA Space Science. 2005. Retrieved 27 October 2010. - "Comet Halley". University of Tennessee. Retrieved 27 December 2006. - "Etymonline: Solar System". Retrieved 24 January 2008. - "1838: Friedrich Bessel Measures Distance to a Star". Observatories of the Carnegie Institution for Science. Retrieved 22 September 2018. - M Woolfson (2000). "The origin and evolution of the solar system". Astronomy & Geophysics. 41 (1): 1.12–1.19. Bibcode:2000A&G....41a..12W. doi:10.1046/j.1468-4004.2000.00012.x. - Alessandro Morbidelli (2005). "Origin and dynamical evolution of comets and their reservoirs". arXiv:astro-ph/0512256. - Audrey Delsanti & David Jewitt (2006). "The Solar System Beyond The Planets" (PDF). Institute for Astronomy, University of Hawaii. Archived from the original (PDF) on 29 January 2007. Retrieved 3 January 2007. - Krasinsky, G.A.; Pitjeva, E.V.; Vasilyev, M.V.; Yagudina, E.I. (July 2002). "Hidden Mass in the Asteroid Belt". Icarus. 158 (1): 98–105. Bibcode:2002Icar..158...98K. doi:10.1006/icar.2002.6837. - Levison, H.F.; Morbidelli, A. (27 November 2003). "The formation of the Kuiper belt by the outward transport of bodies during Neptune's migration". Nature. 426 (6965): 419–421. Bibcode:2003Natur.426..419L. doi:10.1038/nature02120. PMID 14647375. - Harold F. Levison; Martin J Duncan (1997). "From the Kuiper Belt to Jupiter-Family Comets: The Spatial Distribution of Ecliptic Comets". Icarus. 127 (1): 13–32. Bibcode:1997Icar..127...13L. doi:10.1006/icar.1996.5637. - Grossman, Lisa (13 August 2009). "Planet found orbiting its star backwards for first time". New Scientist. Retrieved 10 October 2009. - "The Solar System". Nine Planets. Retrieved 15 February 2007. - Amir Alexander (2006). "New Horizons Set to Launch on 9-Year Voyage to Pluto and the Kuiper Belt". The Planetary Society. Archived from the original on 22 February 2006. Retrieved 8 November 2006. - Marochnik, L. & Mukhin, L. (1995). "Is Solar System Evolution Cometary Dominated?". In Shostak, G.S. (ed.). Progress in the Search for Extraterrestrial Life. Astronomical Society of the Pacific Conference Series. 74. p. 83. Bibcode:1995ASPC...74...83M. ISBN 0-937707-93-7. - Bi, S.L.; Li, T.D.; Li, L.H.; Yang, W.M. (2011). "Solar Models with Revised Abundance". The Astrophysical Journal. 731 (2): L42. arXiv:1104.1032. Bibcode:2011ApJ...731L..42B. doi:10.1088/2041-8205/731/2/L42. - "The Sun's Vital Statistics". Stanford Solar Center. Retrieved 29 July 2008., citing Eddy, J. (1979). A New Sun: The Solar Results From Skylab. NASA. p. 37. NASA SP-402. - Williams, David R. (7 September 2006). "Saturn Fact Sheet". NASA. Archived from the original on 4 August 2011. Retrieved 31 July 2007. - Williams, David R. (16 November 2004). "Jupiter Fact Sheet". NASA. Archived from the original on 26 September 2011. Retrieved 8 August 2007. - Paul Robert Weissman; Torrence V. Johnson (2007). Encyclopedia of the solar system. Academic Press. p. 615. ISBN 978-0-12-088589-3. - Podolak, M.; Weizman, A.; Marley, M. (December 1995). "Comparative models of Uranus and Neptune". Planetary and Space Science. 43 (12): 1517–1522. Bibcode:1995P&SS...43.1517P. doi:10.1016/0032-0633(95)00061-5. - Podolak, M.; Podolak, J.I.; Marley, M.S. (February 2000). "Further investigations of random models of Uranus and Neptune". Planetary and Space Science. 48 (2–3): 143–151. Bibcode:2000P&SS...48..143P. doi:10.1016/S0032-0633(99)00088-4. - Michael Zellik (2002). Astronomy: The Evolving Universe (9th ed.). Cambridge University Press. p. 240. ISBN 978-0-521-80090-7. OCLC 223304585. - Placxo, Kevin W.; Gross, Michael (2006). Astrobiology: a brief introduction. JHU Press. p. 66. ISBN 978-0-8018-8367-5. - "Dawn: A Journey to the Beginning of the Solar System". Space Physics Center: UCLA. 2005. Archived from the original on 24 May 2012. Retrieved 3 November 2007. - Guy Ottewell (1989). "The Thousand-Yard Model \|subtitle Earth as a Peppercorn". NOAO Educational Outreach Office. Retrieved 10 May 2012. - "Tours of Model Solar Systems". University of Illinois. Archived from the original on 12 April 2011. Retrieved 10 May 2012. - "Luleå är Sedna. I alla fall om vår sol motsvaras av Globen i Stockholm". Norrbotten Kuriren (in Swedish). Archived from the original on 15 July 2010. Retrieved 10 May 2010. - See, for example, Office of Space Science (9 July 2004). "Solar System Scale". NASA Educator Features. Retrieved 2 April 2013. - Bouvier, A.; Wadhwa, M. (2010). "The age of the Solar System redefined by the oldest Pb–Pb age of a meteoritic inclusion". Nature Geoscience. 3 (9): 637–641. Bibcode:2010NatGe...3..637B. doi:10.1038/NGEO941. - "Lecture 13: The Nebular Theory of the origin of the Solar System". University of Arizona. Retrieved 27 December 2006. - Irvine, W.M. (1983). "The chemical composition of the pre-solar nebula". Cometary exploration; Proceedings of the International Conference. 1. p. 3. Bibcode:1983coex....1....3I. - Greaves, Jane S. (7 January 2005). "Disks Around Stars and the Growth of Planetary Systems". Science. 307 (5706): 68–71. Bibcode:2005Sci...307...68G. doi:10.1126/science.1101979. PMID 15637266. - Present Understanding of the Origin of Planetary Systems. National Academy of Sciences. 5 April 2000. Retrieved 19 January 2007. - Boss, A.P.; Durisen, R.H. (2005). "Chondrule-forming Shock Fronts in the Solar Nebula: A Possible Unified Scenario for Planet and Chondrite Formation". The Astrophysical Journal. 621 (2): L137. arXiv:astro-ph/0501592. Bibcode:2005ApJ...621L.137B. doi:10.1086/429160. - Bartels, Meghan (18 March 2019). "NASA's New Horizons Reveals Geologic 'Frankenstein' That Formed Ultima Thule". Space.com. Retrieved 18 March 2019. - Sukyoung Yi; Pierre Demarque; Yong-Cheol Kim; Young-Wook Lee; Chang H. Ree; Thibault Lejeune; Sydney Barnes (2001). "Toward Better Age Estimates for Stellar Populations: The Y2 Isochrones for Solar Mixture". Astrophysical Journal Supplement. 136 (2): 417–437. arXiv:astro-ph/0104292. Bibcode:2001ApJS..136..417Y. doi:10.1086/321795. - A. Chrysostomou; P.W. Lucas (2005). "The Formation of Stars". Contemporary Physics. 46 (1): 29–40. Bibcode:2005ConPh..46...29C. doi:10.1080/0010751042000275277. - Schröder, K.-P.; Connon Smith, Robert (May 2008). "Distant future of the Sun and Earth revisited". Monthly Notices of the Royal Astronomical Society. 386 (1): 155–163. arXiv:0801.4031. Bibcode:2008MNRAS.386..155S. doi:10.1111/j.1365-2966.2008.13022.x. - Nir J. Shaviv (2003). "Towards a Solution to the Early Faint Sun Paradox: A Lower Cosmic Ray Flux from a Stronger Solar Wind". Journal of Geophysical Research. 108 (A12): 1437. arXiv:astroph/0306477. Bibcode:2003JGRA..108.1437S. doi:10.1029/2003JA009997. - Pogge, Richard W. (1997). "The Once & Future Sun". New Vistas in Astronomy. Archived from the original on 27 May 2005. Retrieved 7 December 2005. - "Sun: Facts & Figures". NASA. Archived from the original on 2 January 2008. Retrieved 14 May 2009. - Woolfson, M. (2000). "The origin and evolution of the solar system". Astronomy & Geophysics. 41 (1): 12. Bibcode:2000A&G....41a..12W. doi:10.1046/j.1468-4004.2000.00012.x. - Zirker, Jack B. (2002). Journey from the Center of the Sun. Princeton University Press. pp. 120–127. ISBN 978-0-691-05781-1. - "Why is visible light visible, but not other parts of the spectrum?". The Straight Dome. 2003. Retrieved 14 May 2009. - Than, Ker (30 January 2006). "Astronomers Had it Wrong: Most Stars are Single". SPACE.com. Retrieved 1 August 2007. - Smart, R. L.; Carollo, D.; Lattanzi, M. G.; McLean, B.; Spagna, A. (2001). "The Second Guide Star Catalogue and Cool Stars". In Hugh R.A. Jones; Iain A. Steele (eds.). Ultracool Dwarfs: New Spectral Types L and T. Springer. p. 119. Bibcode:2001udns.conf..119S. - T.S. van Albada; Norman Baker (1973). "On the Two Oosterhoff Groups of Globular Clusters". The Astrophysical Journal. 185: 477–498. Bibcode:1973ApJ...185..477V. doi:10.1086/152434. - Charles H. Lineweaver (9 March 2001). "An Estimate of the Age Distribution of Terrestrial Planets in the Universe: Quantifying Metallicity as a Selection Effect". Icarus. 151 (2): 307–313. arXiv:astro-ph/0012399. Bibcode:2001Icar..151..307L. CiteSeerX 10.1.1.254.7940. doi:10.1006/icar.2001.6607. - "Solar Physics: The Solar Wind". Marshall Space Flight Center. 16 July 2006. Retrieved 3 October 2006. - "Voyager Enters Solar System's Final Frontier". NASA. Retrieved 2 April 2007. - Phillips, Tony (15 February 2001). "The Sun Does a Flip". NASA–Science News. Archived from the original on 12 May 2009. Retrieved 4 February 2007. - "A Star with two North Poles". NASA–Science News. 22 April 2003. Archived from the original on 18 July 2009. - Riley, Pete (2002). "Modeling the heliospheric current sheet: Solar cycle variations" (PDF). Journal of Geophysical Research. 107. Bibcode:2002JGRA.107g.SSH8R. doi:10.1029/2001JA000299. Archived from the original (PDF) on 14 August 2009. - "Solar Wind blows some of Earth's atmosphere into space". Science@NASA Headline News. 8 December 1998. - Lundin, Richard (9 March 2001). "Erosion by the Solar Wind". Science. 291 (5510): 1909. doi:10.1126/science.1059763. PMID 11245195. - Langner, U.W.; M.S. Potgieter (2005). "Effects of the position of the solar wind termination shock and the heliopause on the heliospheric modulation of cosmic rays". Advances in Space Research. 35 (12): 2084–2090. Bibcode:2005AdSpR..35.2084L. doi:10.1016/j.asr.2004.12.005. - "Long-term Evolution of the Zodiacal Cloud". 1998. Archived from the original on 29 September 2006. Retrieved 3 February 2007. - "ESA scientist discovers a way to shortlist stars that might have planets". ESA Science and Technology. 2003. Retrieved 3 February 2007. - Landgraf, M.; Liou, J.-C.; Zook, H.A.; Grün, E. (May 2002). "Origins of Solar System Dust beyond Jupiter" (PDF). The Astronomical Journal. 123 (5): 2857–2861. arXiv:astro-ph/0201291. Bibcode:2002AJ....123.2857L. doi:10.1086/339704. Retrieved 9 February 2007. - "Inner Solar System". NASA Science (Planets). Archived from the original on 11 May 2009. Retrieved 9 May 2009. - "Frost line or snow line or ice line in the solar system". Astronoo. Retrieved 28 November 2017. - Ryan Whitwam (18 March 2019). "Mercury Is Actually the Closest Planet to Every Other Planet". ExtremeTech.com. Retrieved 25 March 2019. - Mercury is the closest planet to all seven other planets on YouTube - Schenk P., Melosh H.J. (1994), Lobate Thrust Scarps and the Thickness of Mercury's Lithosphere, Abstracts of the 25th Lunar and Planetary Science Conference, 1994LPI....25.1203S - Bill Arnett (2006). "Mercury". Nine Planets. Retrieved 14 September 2006. - Benz, W.; Slattery, W.L.; Cameron, A.G.W. (1988). "Collisional stripping of Mercury's mantle". Icarus (Submitted manuscript). 74 (3): 516–528. Bibcode:1988Icar...74..516B. doi:10.1016/0019-1035(88)90118-2. - Cameron, A.G.W. (1985). "The partial volatilization of Mercury". Icarus. 64 (2): 285–294. Bibcode:1985Icar...64..285C. doi:10.1016/0019-1035(85)90091-0. - Mark Alan Bullock (1997). The Stability of Climate on Venus (PDF) (PhD). Southwest Research Institute. Archived from the original (PDF) on 14 June 2007. Retrieved 26 December 2006. - Paul Rincon (1999). "Climate Change as a Regulator of Tectonics on Venus" (PDF). Johnson Space Center Houston, TX, Institute of Meteoritics, University of New Mexico, Albuquerque, NM. Archived from the original (PDF) on 14 June 2007. Retrieved 19 November 2006. - "What are the characteristics of the Solar System that lead to the origins of life?". NASA Science (Big Questions). Retrieved 30 August 2011. - Anne E. Egger. "Earth's Atmosphere: Composition and Structure". VisionLearning.com. Retrieved 26 December 2006. - David C. Gatling; Conway Leovy (2007). "Mars Atmosphere: History and Surface Interactions". In Lucy-Ann McFadden; et al. (eds.). Encyclopaedia of the Solar System. pp. 301–314. - David Noever (2004). "Modern Martian Marvels: Volcanoes?". NASA Astrobiology Magazine. Retrieved 23 July 2006. - "Mars: A Kid's Eye View". NASA. Retrieved 14 May 2009. - Scott S. Sheppard; David Jewitt & Jan Kleyna (2004). "A Survey for Outer Satellites of Mars: Limits to Completeness" (PDF). Astronomical Journal. Retrieved 26 December 2006. - Pascal Rosenblatt; Sébastien Charnoz; Kevin M. Dunseath; Mariko Terao-Dunseath; Antony Trinh; Ryuki Hyodo; Hidenori Genda; Stéven Toupin (2016). "Accretion of Phobos and Deimos in an extended debris disc stirred by transient moons" (PDF). Nature Geoscience. 9 (8): 581. Bibcode:2016NatGe...9..581R. doi:10.1038/ngeo2742. - "IAU Planet Definition Committee". International Astronomical Union. 2006. Archived from the original on 3 June 2009. Retrieved 1 March 2009. - "Are Kuiper Belt Objects asteroids? Are large Kuiper Belt Objects planets?". Cornell University. Archived from the original on 3 January 2009. Retrieved 1 March 2009. - Petit, J.-M.; Morbidelli, A.; Chambers, J. (2001). "The Primordial Excitation and Clearing of the Asteroid Belt" (PDF). Icarus. 153 (2): 338–347. Bibcode:2001Icar..153..338P. doi:10.1006/icar.2001.6702. Retrieved 22 March 2007. - "New study reveals twice as many asteroids as previously believed". ESA. 2002. Retrieved 23 June 2006. - "History and Discovery of Asteroids" (DOC). NASA. Retrieved 29 August 2006. - Phil Berardelli (2006). "Main-Belt Comets May Have Been Source of Earths Water". SpaceDaily. Retrieved 23 June 2006. - Barucci, M. A.; Kruikshank, D.P.; Mottola S.; Lazzarin M. (2002). "Physical Properties of Trojan and Centaur Asteroids". Asteroids III. Tucson, Arizona: University of Arizona Press. pp. 273–87. - Morbidelli, A.; Bottke, W.F.; Froeschlé, Ch.; Michel, P. (January 2002). W.F. Bottke Jr.; A. Cellino; P. Paolicchi; R.P. Binzel (eds.). "Origin and Evolution of Near-Earth Objects" (PDF). Asteroids III: 409–422. Bibcode:2002aste.book..409M. - Jack J. Lissauer; David J. Stevenson (2006). "Formation of Giant Planets" (PDF). NASA Ames Research Center; California Institute of Technology. Archived from the original (PDF) on 26 March 2009. Retrieved 16 January 2006. - Pappalardo, R T (1999). "Geology of the Icy Galilean Satellites: A Framework for Compositional Studies". Brown University. Archived from the original on 30 September 2007. Retrieved 16 January 2006. - "Saturn – The Most Beautiful Planet of our solar system". Preserve Articles. 23 January 2011. Archived from the original on 20 January 2012. Retrieved 24 July 2011. - Kargel, J.S. (1994). "Cryovolcanism on the icy satellites". Earth, Moon, and Planets (Submitted manuscript). 67 (1–3): 101–113. Bibcode:1995EM&P...67..101K. doi:10.1007/BF00613296. - Hawksett, David; Longstaff, Alan; Cooper, Keith; Clark, Stuart (2005). "10 Mysteries of the Solar System". Astronomy Now. 19 (8): 65. Bibcode:2005AsNow..19h..65H. - Podolak, M.; Reynolds, R.T.; Young, R. (1990). "Post Voyager comparisons of the interiors of Uranus and Neptune". Geophysical Research Letters (Submitted manuscript). 17 (10): 1737–1740. Bibcode:1990GeoRL..17.1737P. doi:10.1029/GL017i010p01737. - Duxbury, N.S.; Brown, R.H. (1995). "The Plausibility of Boiling Geysers on Triton". Beacon eSpace. Archived from the original on 26 April 2009. Retrieved 16 January 2006. - John Stansberry; Will Grundy; Mike Brown; Dale Cruikshank; John Spencer; David Trilling; Jean-Luc Margot (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope". The Solar System Beyond Neptune. p. 161. arXiv:astro-ph/0702538. Bibcode:2008ssbn.book..161S. - Patrick Vanouplines (1995). "Chiron biography". Vrije Universitiet Brussel. Archived from the original on 2 May 2009. Retrieved 23 June 2006. - Sekanina, Zdeněk (2001). "Kreutz sungrazers: the ultimate case of cometary fragmentation and disintegration?". Publications of the Astronomical Institute of the Academy of Sciences of the Czech Republic. 89: 78–93. Bibcode:2001PAICz..89...78S. - Królikowska, M. (2001). "A study of the original orbits of hyperbolic comets". Astronomy & Astrophysics. 376 (1): 316–324. Bibcode:2001A&A...376..316K. doi:10.1051/0004-6361:20010945. - Whipple, Fred L. (1992). "The activities of comets related to their aging and origin". Celestial Mechanics and Dynamical Astronomy. 54 (1–3): 1–11. Bibcode:1992CeMDA..54....1W. doi:10.1007/BF00049540. - Alan Stern (February 2015). "Journey to the Solar System's Third Zone". American Scientist. Retrieved 26 October 2018. - Stephen C. Tegler (2007). "Kuiper Belt Objects: Physical Studies". In Lucy-Ann McFadden; et al. (eds.). Encyclopedia of the Solar System. pp. 605–620. - Brown, M.E.; Van Dam, M.A.; Bouchez, A.H.; Le Mignant, D.; Campbell, R.D.; Chin, J.C.Y.; Conrad, A.; Hartman, S.K.; Johansson, E.M.; Lafon, R.E.; Rabinowitz, D.L. Rabinowitz; Stomski, P.J., Jr.; Summers, D.M.; Trujillo, C.A.; Wizinowich, P.L. (2006). "Satellites of the Largest Kuiper Belt Objects" (PDF). The Astrophysical Journal. 639 (1): L43–L46. arXiv:astro-ph/0510029. Bibcode:2006ApJ...639L..43B. doi:10.1086/501524. Retrieved 19 October 2011. - Chiang, E.I.; Jordan, A.B.; Millis, R.L.; Buie, M.W.; Wasserman, L.H.; Elliot, J.L.; Kern, S.D.; Trilling, D.E.; Meech, K.J.; et al. (2003). "Resonance Occupation in the Kuiper Belt: Case Examples of the 5:2 and Trojan Resonances" (PDF). The Astronomical Journal. 126 (1): 430–443. arXiv:astro-ph/0301458. Bibcode:2003AJ....126..430C. doi:10.1086/375207. Retrieved 15 August 2009. - M.W. Buie; R.L. Millis; L. H. Wasserman; J.L. Elliot; S.D. Kern; K.B. Clancy; E.I. Chiang; A.B. Jordan; K.J. Meech; R.M. Wagner; D.E. Trilling (2005). "Procedures, Resources and Selected Results of the Deep Ecliptic Survey". Earth, Moon, and Planets. 92 (1): 113–124. arXiv:astro-ph/0309251. Bibcode:2003EM&P...92..113B. doi:10.1023/B:MOON.0000031930.13823.be. - E. Dotto1; M. A. Barucci2; M. Fulchignoni (24 August 2006). "Beyond Neptune, the new frontier of the Solar System" (PDF). Retrieved 26 December 2006. - Fajans, J.; L. Frièdland (October 2001). "Autoresonant (nonstationary) excitation of pendulums, Plutinos, plasmas, and other nonlinear oscillators" (PDF). American Journal of Physics. 69 (10): 1096–1102. Bibcode:2001AmJPh..69.1096F. doi:10.1119/1.1389278. Archived from the original (PDF) on 7 June 2011. Retrieved 26 December 2006. - Marc W. Buie (5 April 2008). "Orbit Fit and Astrometric record for 136472". SwRI (Space Science Department). Retrieved 15 July 2012. - Michael E. Brown. "The largest Kuiper belt objects" (PDF). Caltech. Retrieved 15 July 2012. - Ortiz, J. L.; Santos-Sanz, P.; Sicardy, B.; et al. (2017). "The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation". Nature. 550 (7675): 219–223. Bibcode:2017Natur.550..219O. doi:10.1038/nature24051. hdl:10045/70230. PMID 29022593. - David Jewitt (2005). "The 1000 km Scale KBOs". University of Hawaii. Retrieved 16 July 2006. - "List of Centaurs and Scattered-Disk Objects". IAU: Minor Planet Center. Retrieved 2 April 2007. - Brown, Michael E.; Schaller, Emily L. (15 June 2007). "The Mass of Dwarf Planet Eris". Science. 316 (5831): 1585. Bibcode:2007Sci...316.1585B. doi:10.1126/science.1139415. PMID 17569855. - Littmann, Mark (2004). Planets Beyond: Discovering the Outer Solar System. Courier Dover Publications. pp. 162–163. ISBN 978-0-486-43602-9. - Fahr, H. J.; Kausch, T.; Scherer, H. (2000). "A 5-fluid hydrodynamic approach to model the Solar System-interstellar medium interaction" (PDF). Astronomy & Astrophysics. 357: 268. Bibcode:2000A&A...357..268F. See Figures 1 and 2. - "Cassini's Big Sky: The View from the Center of Our Solar System". NASA/JPL. 2009. Retrieved 20 December 2009. - Stone, E.C.; Cummings, A.C.; McDonald, F.B.; Heikkila, B.C.; Lal, N.; Webber, W.R. (September 2005). "Voyager 1 explores the termination shock region and the heliosheath beyond". Science. 309 (5743): 2017–20. Bibcode:2005Sci...309.2017S. doi:10.1126/science.1117684. PMID 16179468. - Stone, E.C.; Cummings, A.C.; McDonald, F.B.; Heikkila, B.C.; Lal, N.; Webber, W.R. (July 2008). "An asymmetric solar wind termination shock". Nature. 454 (7200): 71–4. Bibcode:2008Natur.454...71S. doi:10.1038/nature07022. PMID 18596802. - Cook, Jia-Rui C.; Agle, D. C.; Brown, Dwayne (12 September 2013). "NASA Spacecraft Embarks on Historic Journey into Interstellar Space". NASA. Retrieved 12 September 2013. - Nemiroff, R.; Bonnell, J., eds. (24 June 2002). "The Sun's Heliosphere & Heliopause". Astronomy Picture of the Day. NASA. Retrieved 23 June 2006. - "Voyager: Interstellar Mission". NASA Jet Propulsion Laboratory. 2007. Retrieved 8 May 2008. - R. L. McNutt, Jr.; et al. (2006). "Innovative Interstellar Explorer" (PDF). Physics of the Inner Heliosheath: Voyager Observations, Theory, and Future Prospects. AIP Conference Proceedings. 858. pp. 341–347. Bibcode:2006AIPC..858..341M. doi:10.1063/1.2359348. - Anderson, Mark (5 January 2007). "Interstellar space, and step on it!". New Scientist. Retrieved 5 February 2007. - David Jewitt (2004). "Sedna – 2003 VB12". University of Hawaii. Retrieved 23 June 2006. - Mike Brown (2004). "Sedna". Caltech. Retrieved 2 May 2007. - "JPL Small-Body Database Browser: (2012 VP113)" (2013-10-30 last obs). Jet Propulsion Laboratory. Retrieved 26 March 2014. - "A new object at the edge of our Solar System discovered". Physorg.com. 26 March 2014. - Stern SA, Weissman PR (2001). "Rapid collisional evolution of comets during the formation of the Oort cloud". Nature. 409 (6820): 589–591. doi:10.1038/35054508. PMID 11214311. - Bill Arnett (2006). "The Kuiper Belt and the Oort Cloud". Nine Planets. Retrieved 23 June 2006. - T. Encrenaz; JP. Bibring; M. Blanc; MA. Barucci; F. Roques; PH. Zarka (2004). The Solar System: Third edition. Springer. p. 1. - Durda D.D.; Stern S.A.; Colwell W.B.; Parker J.W.; Levison H.F.; Hassler D.M. (2004). "A New Observational Search for Vulcanoids in SOHO/LASCO Coronagraph Images". Icarus. 148 (1): 312–315. Bibcode:2000Icar..148..312D. doi:10.1006/icar.2000.6520. - English, J. (2000). "Exposing the Stuff Between the Stars" (Press release). Hubble News Desk. Retrieved 10 May 2007. - R. Drimmel; D.N. Spergel (2001). "Three Dimensional Structure of the Milky Way Disk". The Astrophysical Journal. 556 (1): 181–202. arXiv:astro-ph/0101259. Bibcode:2001ApJ...556..181D. doi:10.1086/321556. - Eisenhauer, F.; et al. (2003). "A Geometric Determination of the Distance to the Galactic Center". The Astrophysical Journal. 597 (2): L121–L124. arXiv:astro-ph/0306220. Bibcode:2003ApJ...597L.121E. doi:10.1086/380188. - Leong, Stacy (2002). "Period of the Sun's Orbit around the Galaxy (Cosmic Year)". The Physics Factbook. Retrieved 2 April 2007. - C. Barbieri (2003). "Elementi di Astronomia e Astrofisica per il Corso di Ingegneria Aerospaziale V settimana". IdealStars.com. Archived from the original on 14 May 2005. Retrieved 12 February 2007. - Reid, M.J.; Brunthaler, A. (2004). "The Proper Motion of Sagittarius A*". The Astrophysical Journal. 616 (2): 872–884. arXiv:astro-ph/0408107. Bibcode:2004ApJ...616..872R. doi:10.1086/424960. - Leslie Mullen (18 May 2001). "Galactic Habitable Zones". Astrobiology Magazine. Retrieved 24 April 2015. - O. Gerhard (2011). "Pattern speeds in the Milky Way". Mem. S.A.It. Suppl. 18: 185. arXiv:1003.2489. Bibcode:2011MSAIS..18..185G. - "Supernova Explosion May Have Caused Mammoth Extinction". Physorg.com. 2005. Retrieved 2 February 2007. - "Our Local Galactic Neighborhood". NASA. 5 June 2013. Archived from the original on 21 November 2013. - Into the Interstellar Void, Centauri Dreams, 5 June 2013 - "Near-Earth Supernovas". NASA. Archived from the original on 13 August 2006. Retrieved 23 July 2006. - Anglada-Escudé, Guillem; Amado, Pedro J.; Barnes, John; Berdiñas, Zaira M.; Butler, R. Paul; Coleman, Gavin A. L.; de la Cueva, Ignacio; Dreizler, Stefan; Endl, Michael; Giesers, Benjamin; Jeffers, Sandra V.; Jenkins, James S.; Jones, Hugh R. A.; Kiraga, Marcin; Kürster, Martin; López-González, Marίa J.; Marvin, Christopher J.; Morales, Nicolás; Morin, Julien; Nelson, Richard P.; Ortiz, José L.; Ofir, Aviv; Paardekooper, Sijme-Jan; Reiners, Ansgar; Rodríguez, Eloy; Rodrίguez-López, Cristina; Sarmiento, Luis F.; Strachan, John P.; Tsapras, Yiannis; Tuomi, Mikko; Zechmeister, Mathias (25 August 2016). "A terrestrial planet candidate in a temperate orbit around Proxima Centauri". Nature. 536 (7617): 437–440. arXiv:1609.03449. Bibcode:2016Natur.536..437A. doi:10.1038/nature19106. ISSN 0028-0836. PMID 27558064. - "Stars within 10 light years". SolStation. Retrieved 2 April 2007. - "Tau Ceti". SolStation. Retrieved 2 April 2007. - Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun, K.L. Luhman 2014 ApJ 786 L18. doi:10.1088/2041-8205/786/2/L18 - The Solar System as an Exoplanetary System, Rebecca G. Martin, Mario Livio, (Submitted on 4 August 2015) - How Normal is Our Solar System?, By Susanna Kohler on 25 September 2015 - Consolidating and Crushing Exoplanets: Did it happen here?, Kathryn Volk, Brett Gladman, (Submitted on 23 February 2015 (v1), last revised 27 May 2015 (this version, v2)) - Mercury Sole Survivor of Close Orbiting Planets, Nola Taylor Redd. 8 June 2015 - Final Stages of Planet Formation, Peter Goldreich, Yoram Lithwick, Re'em Sari, (Submitted on 13 April 2004) - Encyclopædia Britannica. 25 (11th ed.). 1911. pp. 157–158. . - A Cosmic History of the Solar System - A Tediously Accurate Map of the Solar System (web based scroll map scaled to the Moon being 1 pixel) - NASA's Solar System Simulator - NASA/JPL Solar System main page - Solar System Profile by NASA's Solar System Exploration
To see if a micro-hydropower system would work for you, determine the vertical distance (head) available and flow (quantity) of the water. To build a micro-hydropower system, you need access to flowing water on your property. A sufficient quantity of falling water must be available, which usually, but not always, means that hilly or mountainous sites are best. Other considerations for a potential micro-hydropower site include its power output, economics, permits, and water rights. To see if a micro-hydropower system would work for you, you will want to determine the amount of power that you can obtain from the flowing water on your site. This involves determining these two things: - Head -- the vertical distance the water falls - Flow -- the quantity of water falling. Once you've determined the head and flow, then you can use a simple equation to estimate the power output for a system with 50% to 70% efficiency or more, which is representative of most micro-hydropower systems. Simply multiply net head (the vertical distance available after subtracting losses such as pipe friction - the losses will depend on the type size of the pipe among other things, but can be estimated to be from 5 to 10 percent for preliminary calculations) by flow (use U.S. gallons per minute) divided by 10. That will give you the system's output in watts (W). The equation looks this: [net head (feet) × flow (gpm)] ÷ 10 = W (Power or Watts) Determining the “Head” at Your Potential Micro-hydropower Site In a potential micro-hydropower site, head is the vertical distance that water falls. When evaluating a potential site, head is usually measured in feet, meters, or units of pressure. Head also is a function of the characteristics of the channel or pipe through which it flows. Most micro-hydropower sites are categorized as low or high head. The higher the head the better because you'll need less water to produce a given amount of power and you can use smaller, less expensive equipment. Low head refers to a change in elevation of less than 66 feet (20 meters), and ultralow head refers to a change in elevation of less than 10 feet (3 meters). A vertical drop of less than 2 feet (0.6 meters) will probably make a small-scale hydroelectric system unfeasible. However, for extremely small power generation amounts, a flowing stream with as little as 13 inches of water can support a submersible turbine. This type of turbine was originally used to power scientific instruments towed behind oil exploration ships, and are similar to some hydrokinetic power systems from river or tidal currents. When determining head, you need to consider both gross head and net head. Gross head is the vertical distance between the top of the forebay water level where the penstock (or pipe) that conveys the water under pressure is attached and the level of water where the turbine water discharges. Net head equals gross head minus losses due to friction and turbulence in the piping. The most accurate way to determine gross head is to have a professional survey the site. To get a rough estimate, you can use U.S. Geological Survey maps of your area or the hose-tube method. The hose-tube method for determining head involves taking stream-depth measurements across the width of the stream you intend to use for your system -- from the point at which you want to place the penstock to the point at which you want to place the turbine. You will need the following: - An assistant - A 20–30 foot (6–9 meters) length of small-diameter garden hose or other flexible tubing - A funnel - A yardstick or measuring tape. - Stretch the hose or tubing down the stream channel from the point that is the most practical elevation for the penstock intake. Have your assistant hold the upstream end of the hose, with the funnel in it, underwater as near the surface as possible. - Meanwhile, lift the downstream end until water stops flowing from it. Measure the vertical distance between your end of the tube and the surface of the water. This is the gross head for that section of stream. - Have your assistant move to where you are and place the funnel at the same point where you took your measurement. Then walk downstream and repeat the procedure. Continue taking measurements until you reach the point where you plan to site the turbine. The sum of these measurements will give you a rough approximation of the gross head for your site. Note: due to the water's force into the upstream end of the hose, water may continue to move through the hose after both ends of the hose are actually level. You may wish to subtract an inch or two (2–5 centimeters) from each measurement to account for this. It is best to be conservative in these preliminary gross head measurements. If your preliminary estimates look favorable, you will want to acquire more accurate measurements. As stated already, the most accurate way to determine head is to have a professional survey your site. But if you know you have an elevation drop on your site of several hundred feet, you can use an aircraft altimeter. You may be able to buy, borrow, or rent an altimeter from a small airport or flying club. A word of caution, however: while using an altimeter might be less expensive than hiring a professional surveyor, your measurement will be less accurate. In addition, you will have to account for the effects of barometric pressure and calibrate the altimeter as necessary. Determining “Flow” at A Potential Micro-hydropower Site The quantity of water falling from a potential micro-hydropower site is called flow. It's measured in gallons per minute, cubic feet per second, or liters per second. The easiest way to determine your stream's flow is to obtain data from these local offices: - The U.S. Geological Survey - The U.S. Army Corps of Engineers - The U.S. Department of Agriculture - Your county's engineer - Local water supply of flood control authorities. If you can't obtain existing data, you'll need to conduct your own flow measurements. You can measure flow using the bucket or weighted-float method. The bucket method involves damming your stream with logs or boards to divert its flow into a bucket or container. The rate at which the container fills is the flow rate. For example, a 5-gallon bucket that fills in 1 minute means that your stream's water is flowing at 5 gallons per minute. Another way to measure flow involves measuring stream depths across the width of the stream and releasing a weighted-float upstream from your measurements. Due to water safety concerns, this method isn't recommended if the stream is fast-flowing and/or over your calves. You will need: - An assistant - A tape measure - A yardstick or measuring rod - A weighted-float, such as a plastic bottle filled halfway with water - A stopwatch - Some graph paper. With this equipment you can calculate flow for a cross section of the streambed at its lowest water level. - First, select a stretch of stream with the straightest channel, and the most uniform depth and width possible. - At the narrowest point, measure the width of the stream. - Then, holding the yardstick vertically, walk across the stream and measure the water depth at one-foot increments. To help with the process, stretch a string or rope upon which the increments are marked across the stream width. - Plot the depths on graph paper to give yourself a cross-sectional profile of the stream. - Determine the area of each section by calculating the areas of the rectangles (area = length × width) and right triangles (area = ½ base × height) in each section. - Next, from the same point where you measured the stream's width, mark a point at least 20 feet upstream. - Release the weighted-float in the middle of the stream and record the time it takes for the float to travel to your original point downstream. Don't let the float drag along the bottom of the streambed; if it does, use a smaller float. - Divide the distance between the two points by the float time in seconds to get flow velocity in feet per second. The more times you repeat this procedure, the more accurate your flow velocity measurement will be. - Multiply the average velocity by the cross-sectional area of the stream. - Then multiply your result by a factor that accounts for the roughness of the stream channel (0.8 for a sandy streambed, 0.7 for a bed with small to medium sized stones, and 0.6 for a bed with many large stones). The result will give you the flow rate in cubic feet or meters per second. Stream flows can be quite variable over a year, so the season during which you take flow measurements is important. Unless you're considering building a storage reservoir, you can use the lowest average flow of the year as the basis for your system's design. However, if you're legally restricted on the amount of water you can divert from your stream at certain times of the year, use the average flow during the period of the highest expected electricity demand. If you determine from your estimated power output that a microhydropower system would be feasible, then you can determine whether it economically makes sense. Since saving energy costs less than generating it, be sure your home is as energy efficient as possible, reducing your electricity usage so that you do not purchase a system that is bigger (and more costly) than you need. Add up all the estimated costs of developing and maintaining the site over the expected life of your equipment, and divide the amount by the system's capacity in Watts. This will tell you how much the system will cost in dollars per Watt. Then you can compare that to the cost of utility-provided power or other alternative power sources. Whatever the upfront costs, a hydroelectric system will typically last a long time and, in many cases, maintenance is not expensive. In addition, sometimes there are a variety of financial incentives available on the state, utility, and federal level for investments in renewable energy systems. They include income tax credits, property tax exemptions, state sales tax exemption, loan programs, and special grant programs, among others. Permits and Water Rights When deciding whether to install a micro-hydropower system on your property, you also need to know your local permit requirements and water rights. Whether your system will be grid-connected or stand-alone will affect what requirements you must follow. If your micro-hydropower system will have minimal impact on the environment, and you are not planning to sell power to a utility, the permitting process will most likely involve minimal effort. Locally, your first point of contact should be the county engineer. Your state energy office may be able to provide you with advice and assistance as well. In addition, you'll need to contact the Federal Energy Regulatory Commission and the U.S. Army Corps of Engineers. You'll also need to determine how much water you can divert from your stream channel. Each state controls water rights; you may need a separate water right to produce power, even if you already have a water right for another use. See planning for a small renewable energy system for more information on state and community codes and requirements for small renewable energy systems.
In my last post (“Darlingtonia” on 06-11-2018) I described the structure of a Darlingtonia (Darlingtonia californica) plant. This carnivorous plant, which often grows on nutrient-poor substrates, has evolved its unusual form to trap insects and thus supplement its nutritional requirements. Insects, lured by fragrant nectar, land on the plant’s “tongue” or the mustache-like appendages under the head or hood. Slanting hairs guide the insects toward an opening at the base of the hood. These slanting hairs also block the insect’s escape. Once inside, insects try to escape by flying out of translucent spots on the top and back of the hood. These spots keep the insects away from the entrance hole. As they continuously attempt to fly out of the “false windows” the insects tire and fall into the water which fills the bottom of the hollow leaf. The walls of the plant tube are waxy and slippery and have downward pointing hairs, which prevents the insects from climbing back up the tube. The insects are decomposed by microorganisms in the fluid. The released nutrients are absorbed by the plant. The picture above shows a sludge of insects in the base of the Darlingtonia tube. Darlingtonia plants do not trap rainwater. Instead the water in the base of the plant is secreted by the plant itself and the water level is kept constant by pumping water from the roots. The cells lining the base of the hollow tube that absorb the nutrients are the same as those cells on the Darlingtonia roots that absorb nutrients from the soil. General consensus has been that bacteria decompose the insects in the water trap and that Darlingtonia does not secrete proteolytic enzymes. However, recent studies suggest that Darlingtonia does also excrete enzymes into the water which help digest the insects. These Darlingtonia specimens were photographed along Howland Hill Road in the Redwoods National State Parks and along Stony Creek and Myrtle Creek Trails in the Smith River National Recreation Area, all in Del Norte County CA. The way Darlingtonia adapted to survive on nutrient-poor soils amazes me.
In this book, Deidre Martin and Carol Miller aim to discuss in some detail the range of speech and language difficulties which children may experience in the classroom and to offer the practitioner an educational perspective on these difficulties. They also discuss the speech and language difficulties from other perspectives, namely medical, linguistic and psycholinguistic and their various approaches to understanding these difficulties. They believe that the educational perspective is the one likely to be the most useful to those who are involved in the teaching and learning of pupils with speech and language difficulties, as well as their parents and other associated professionals. The book opens with two chapters setting out terms, concepts and perspectives on speech and language. Subsequent chapters deal with a range of speech and language difficulties which are usually recognised and identified in the classroom. There is a chapter on literacy as difficulties in reading, writing and spelling are closely rooted in language processing. This second edition reflects some of the changes in Government Policies and also research since the first edition was published in 2001, for example, greater emphasis on inclusion and the need for practitioners to be well informed. In this edition a greater emphasis is placed on ‘needs’ rather than ‘difficulties’ implying now that those needs can be addressed. As well as updating references and information the authors have included more on issues of assessment and intervention and on emotion and behaviour as these are closely related to communication.
Python is a general purpose programming language that is dynamically typed, interpreted, and is known for its easy readability with great design principles. It was created by Guido van Rossum and released in 1991. Since then, the language has exploded in popularity. To learn more about Python from its source check out these pages on python.org: If you're new to programming, you've made the right choice. Python is the perfect beginners' language. It has a clear and simple syntax that will get you writing useful programs in short order. Python even has an interactive mode, which offers immediate feedback, allowing you to test out new ideas almost instantly. If you've done some programming before, you've still made the right choice. Python has all the power and flexibility you'd expect from a modern, object-oriented programming language. But even with all of its power, you may be surprised how quickly you can build programs. In fact, ideas translate so quickly to the computer, Python has been called "programming at the speed of thought". - Michael Dawson Python 2 or Python 3 Python 3 was released on December 3, 2008. The two versions are similar and, with knowledge of one, writing code for the other is not difficult. Three changes most commonly encountered in going from 2.x to 3.x include: print()function (it is now a function and requires parentheses) input()function (is no longer - integer division (Python 3 no longer floors this operation but always creates a float) A full list of changes can be found here. Other considerations include: - Python 2.x will not be maintained past 2020 - 3.x is under active development. This means that all recent standard library improvements, for example, are only available by default in Python 3.x - The Python ecosystem has amassed a significant amount of quality software over the years. The downside of breaking backwards compatibility in 3.x is that some of that software (especially in-house software in companies) still doesn't yet work on 3.x For more information see Python 2 or Python 3. Most nix based operating systems (including Mac OS) come with Python installed. Replacing a system’s native Python, whatever its version is, is not recommended and may cause problems because the version installed could be being used for some necessary internal services or tools. However, different versions of Python can be safely installed alongside the system Python. See Python Setup and Usage. Python doesn't ship with Windows. The installer and instructions can be found here. Linux operating systems come with different versions of Python pre-installed. However to install Python 3.x on Linux, follow this link. MacOS doesn't come with Python 3 (however Python 2.7 pre-installed by Apple), the installer and instructions can be found here. Windows doesn't typically come with Python, the installer and instructions can be found here. The Python Interpreter The Python interpreter is used to run Python scripts, it translates Python code for the operating system. In your terminal, type the command python followed by the script name to invoke the interpreter and run the script. This will determine whether the interpreter is available and in Unix shell’s search path. To execute a script this would be followed by the script name to invoke the interpreter and run the script. hello_campers.py contains the following code: From a terminal: $ python hello_campers.py Hello campers! When multiple versions of Python are installed, calling them by version may be possible depending on the install configuration. In the Cloud9 IDE custom environment, they can be invoked as shown below: $ python --version Python 2.7.6 $ python3 --version Python 3.4.3 $ python3.5 --version Python 3.5.1 $ python3.6 --version Python 3.6.2 $ python3.7 --version Python 3.7.1 Python Interpreter Interactive Mode Interactive mode can be started by invoking the Python interpreter with the -i flag or without any arguments. Interactive mode provides a prompt where Python commands can be entered and run, this is commonly used for learning Python or trying out statements: $ python3.5 Python 3.5.1 (default, Dec 18 2015, 00:00:00) GCC 4.8.4 on linux Type "help", "copyright", "credits" or "license" for more information. >>> print("Hello campers!") Hello campers! >>> 1 + 2 3 >>> exit() $ There are many common applications for interactive Python including the one built in to your Python version, available at the command prompt by invoking the version name, as well downloadable applications such as Idle, Spyder and many more. The Zen of Python The principles that influenced the design of Python are included as an Easter egg, and can be read by using the following command inside the Python interpreter interactive mode: >>> import this The Zen of Python, by Tim Peters Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. Special cases aren't special enough to break the rules. Although practicality beats purity. Errors should never pass silently. Unless explicitly silenced. In the face of ambiguity, refuse the temptation to guess. There should be one-- and preferably only one --obvious way to do it. Although that way may not be obvious at first unless you're Dutch. Now is better than never. Although never is often better than right* now. If the implementation is hard to explain, it's a bad idea. If the implementation is easy to explain, it may be a good idea. Namespaces are one honking great idea -- let's do more of those! Pros and Cons of Python Pros and Cons of Python - Easy to read, learn, and write. - Interactive language with module support for almost all functionality. - Open Source: You can contribute to the community and help others with the functions you have developed. - A lot of good interpreters and notebooks available for better experience like Jupyter notebook. - It is a very easy language to debug. To check if a small bit of code works or not, you can just open up the interpreter and test. - There are multiple libraries available for Python, like numpy, pandas, etc., to make doing complex operations easy! - Don't have to worry about range of data types. For instance, in the C language, we have to specify data types such as long long int. - Being open source, many different ways have developed over the years for the same function. This can sometimes create chaos for others when reading someone else's code. - It can be a slow language in some implementations because it is interpreted. This can be a deficit for developing some general algorithms. - Python is dynamically typed, so the errors in code only show up after running an application. - Python is not the best language to use if your project requires efficient memory management. - White space can confuse beginners, as spaces may change depending on the program. Python is well documented. These docs include tutorials, guides, references, and meta information for the language. ... often the quickest way to debug a program is to add a few print statements to the source: the fast edit-test-debug cycle makes this simple approach very effective. Python also includes more powerful tools for debugging, such as: Just note that these exist for now. A Hello World Exercise print(objects, sep=' ', end='\n', file=sys.stdout, flush=False) The built-in functions are listed in alphabetical order. The name is followed by a parenthesized list of formal parameters with optional default values. Under that is a short description of the function and its parameters are given. Occasionally, an example is provided. >>> print("Hello, World!") Hello, World! A function is called when the name of the function is followed by (). For the 'Hello, World!' example, the print function is called with a string as an argument for the first parameter. For the rest of the parameters, default values are used. The argument that we called the str object or string, one of Python's built-in data types. Also the most important thing about python is that you don't have to specify the data type while declaring a variable Python's compiler will do that itself, based on the type of value assigned. objects parameter is prefixed with a , which indicates that the function will take an arbitrary number of arguments for that parameter. Things you can do with Python As stated, Python is a general purpose language. You can use it to do anything you like but one of the major uses of Python is in machine learning and artificial intelligence. It is also a popular language in web development with some amazing frameworks like Django and flask. It is also a popular scripting language. With its easy to read syntax it is becoming one the most popular programming languages, growing rapidly in different fields. For security professionals, Python can be used for but not limited to: - Penetration testing - Information gathering - Scripting tools - Automating stuff Want to learn more? Free Code Camp has some great resources. The web is a big place, there's plenty more to explore: - Python Practice Book - Think Python - Practical Business Python - Real Python - Full Stack Python - Learn the Basics on codecademy - Computer science using Python on edX - Intro to Computer Science CS101 on Udacity - List of more resources for learning python on Awesome Python - Interactive Python - How to Think Like a Computer Scientist - Everyday Python Project - Python Developer’s Guide - Learn Python the Hard Way book - Introduction to Python Programming on Udacity - Profiling in Python - Python for Everybody Specialization
Blood pressure can be described as the force with which the blood pushes through the artery walls through the body. Blood in the arteries fills the arteries up to a certain extent implying that too much blood pressure can cause damages to the artery. Blood pressure is measured using two methods that are systolic pressure which refers to the pressure in the arterial system at its highest. Diastolic pressure on the other hand refers to arterial pressure at its lowest. The measure of blood pressure hence appears as two numbers where the upper number is the systolic pressure while the lower number is diastolic pressure. What Is Hypertension? Hypertension refers to the reading of 140/90 on three consecutive measurement at least six hours part. The definition of the term varies from one individual where in the case of pregnant mothers; it is defined as 140/90 on two consecutive measures six hours apart. Hypertension leads to the heart working harder than it should be which can lead to the damage of the coronary arteries, the brain and the kidney. Hypertension has been found to be a major cause of stroke. Types of Hypertension Hypertension can either be classified as primary hypertension or secondary hypertension. The origin of primary hypertension is highly associated with lifestyle. According to Gibson, this type of hypertension is responsible for up to 90% of all diagnosed hypertension and are treated using stress management techniques, proper medication, increasing physical activities and diet changes (Gibson, 2009). The cause of primary hypertension is as a result of preexisting medical conditions such as congestion of the heart and damages to the endocrine system. Pregnancy-induced hypertension (PIH) appears in healthy women during the 20th week of pregnancy. The occurrence of this type of hypertension commonly occurs in obese or overweight women. PIH is characterized by water retention in the body and protein in the urine. Medical practitioners have found out that 5% of all PIH cases progress to preeclampsia. This condition is characterized by loss of appetite, dizziness, visual disturbance, abdominal pains and headaches. Preeclampsia affects the blood system and the kidney as well as other organs. PIH has been found to disappear a few weeks after birth. Causes of Hypertension Pre4wcription drugs and other over the counter drugs have been found to cause hypertension. An example of these is corticosteroids and immunosuppressive drugs which have been closely associated with increased hypertension cases in most organ transplant recipients (Anderson, Mosby's Medical, Nursing, and Allied Health Dictionary). Other drugs found to increase the occurrence of hypertension in the body are nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) since some of their properties such as antiprostaglandin affect the kidney. Other causes of hypertension include tobacco products where the nicotine contained n these products increase the blood pressure in the body. Medical researchers have not established a direct connection between caffeine and chronic hypertension. However, caffeine intake can cause acute increase in blood pressure. Hypertension is also caused by chronic use of alcohol. According to recent research, 30 to 60% of alcoholics have hypertension. 5% of all hypertension cases are also as a result of alcohol consumption. Diet and Hypertension Sodium intake is ranked fourth as the lifestyle factor that is closely associated with hypertension. An estimated half of the people has been found to be sodium sensitive. This can be attributed to the fact that excessive sodium consumption tends to increase blood pressure in the body. There are various ways that one can limit sodium intake in the body. One such way is by check food labels for sodium content. Another way is by choosing unprocessed food as well as limiting processed meats and cheese. Another protective strategy is by limiting consumption of salty snacks and other condiments of food that may be high in sodium. With regards to this, Vicki being diagnosed with hypertension can be attributed to two factors. One factor is that of her age. This is because; most of the sodium sensitive individuals fall under the age bracket of 40 to 70 years of age. The other factor is as a result of Vicki taking most of her meals form fast food restaurants. This implies that at most instances, she hardly checks the food labels for sodium content. Fast foods also contain high fat content which is one of the factors that increase the blood pressure in the body.
The tropical rain forest is one of several major biomes, or ecoregions, on planet Earth. Others include temperate forests, deserts, grasslands and tundra. Each biome has a distinct set of environmental conditions to which animals are adapted. Animal adaptations occur through the process of evolution. Successive generations of animals change in response to environmental conditions through the process of natural selection. Evolution is a process by which, over long periods of time, a particular kind of life form can develop into an entirely new species. During the course of this change many smaller adaptations can occur, and these contribute to overall evolution. Process or Characteristic Adaptation can be a process or a characteristic. A set or series of relatively small changes that add up, over time, can result in a major evolutionary change. Some of these small changes are adaptations. That is the process of adaptation. The result of the process -- on the other hand -- is a characteristic or physical feature, also called an adaptation. An example is the emerald tree boa. It is native to the tropical rain forests of South America. The emerald tree boa is adapted to life in the trees. One conspicuous adaptation is the boa’s color, which helps to conceal it in the rainforest canopy. The boa’s front teeth are extra long, an adaption the facilitates capturing its prey. Paleontologists are scientists who study ancient or extinct life forms. A large part of their work is focused on fossil evidence. Through studying the fossil record, paleontologists can discover and track animal adaptations as they have occurred through prehistory. Parts of the earth that are now temperate forest or other biomes once had thriving tropical rainforests. An example of an animal adapted to life in the tropical rain forest is the crocodile. While some lines of evolution indicate that animals have changed and adapted dramatically into different forms, the crocodile is evidently so well adapted that it has changed very little over many millions of years. As scientists understand evolution, it is a continuous process, so there is not necessarily a final set of adaptations. Scientists expect virtually every animal in the tropical rainforest to continue to evolve and develop new adaptations to changing environmental conditions in the future. Although scientists may be able to make some predictions about the future, the future has no means of direct study or observation. Future adaptations of animals in the tropical rain forest, therefore, are a matter of speculation. About the Author Donald Miller has a background in natural history, environmental work and conservation. His writing credits include feature articles in major national print magazines and newspapers, including "American Forests" and a nature column for "Boys' Life Magazine." Miller holds a Bachelor of Science in natural resources conservation.
A glossary of definitions for terms relating to biodiversity, ecosystems services and conservation. All definitions are referenced, where possible preference has been given to internationally recognised definitions (for example those defined by international conventions or agreements). The terms have been chosen to support understanding of biodiversity and conservation issues, and terms relating to biodiversity loss are complemented by those relating to conservation responses supported by international conservation organisations, governments, scientists and business sectors. More detailed explanations are provided for a number of key terms, to provide further background information. The terms can be filtered by category to aid in the navigation of the many definitions. The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. An ecosystem has recovered when it contains sufficient biotic and abiotic resources to continue its development without further assistance or subsidy. It would sustain itself structurally and functionally, demonstrate resilience to normal ranges of environmental stress and disturbance, and interact with contiguous ecosystems in terms of biotic and abiotic flows and cultural interactions.
Male and female sharks differ in that male sharks have modified pelvic fins called claspers, while female sharks do not. Furthermore, male sharks have testes, while female sharks have ovaries. Male sharks also have two muscular sacs known as siphon sacs located in their abdominal wall. Claspers are considered to be part of a male shark's sexual organs because they are used during mating. They are an external organ used to funnel and deliver sperm to the sexual organs of the female shark. During the mating process, one of the claspers is raised to allow sea water into the siphon sacs. The sea water inside the sacs is ejected under pressure and used to inject the male shark's sperm into the reproductive organs of the female shark. The second clasper is inserted into the cloaca, which is the reproductive opening of the female shark. Once inserted, it opens like an umbrella and anchors the male shark in place for mating. Claspers are also used to determine the sexual maturity of male sharks. The claspers of young male sharks remain soft and flexible, while those of male sharks that have reached sexual maturity have been hardened by calcium deposits, causing them to become rigid and inflexible.
Understanding the causes of disease in Antarctic wildlife is crucial, as many of these species are already threatened by environmental changes brought about by climate change. In recent years, Antarctic penguins have been showing signs of an unknown pathology: a feather disorder characterised by missing feathers, resulting in exposed skin. During the 2018-2019 austral summer breeding season at Cape Crozier colony on Ross Island, Antarctica, we observed for the first time an Adélie penguin chick missing down over most of its body. A guano sample was collected from the nest of the featherless chick, and using high-throughput sequencing, we identified a novel circovirus. Using abutting primers, we amplified the full genome, which we cloned and Sanger-sequenced to determine the complete genome of the circovirus. The Adélie penguin guano-associated circovirus genome shares <67% genome-wide nucleotide identity with other circoviruses, representing a new species of circovirus; therefore, we named it penguin circovirus (PenCV). Using the same primer pair, we screened 25 previously collected cloacal swabs taken at Cape Crozier from known-age adult Adélie penguins during the 2014-2015 season, displaying no clinical signs of feather-loss disorder. Three of the 25 samples (12%) were positive for a PenCV, whose genome shared >99% pairwise identity with the one identified in 2018-2019. This is the first report of a circovirus associated with a penguin species. This circovirus could be an etiological agent of the feather-loss disorder in Antarctic penguins.
1. Being a Dolphin You will discover the main features that make a dolphin such a special animal and its marine habitat. Using simple tools, you learn about their physiology: their size, their ability to hold their breath and see in the dark, the way they communicate with different sounds. You will have the unique opportunity to observe dolphins and learn from their animal-care staff, who know them best as they spend their whole day with them. - Worksheet "Comparison with a dolphin" - Posters 1, 2, 3, 4, 5, 6 (Marlisco program) - Poster & Presentation (WhichFish campaign) 2. Habitats - Where do Animals Live The African Savannah is a dry open space that shows no mercy from the ferocious predators that roam freely over the plains. A Tropical Rainforest on the other hand may have many hiding places but unexpected dangers lurk around the corner. What makes up a habitat, which animals live there and how do they survive in the harsh conditions of the wild? Learn about amazing animal survival tactics, the problems that arise when humans and wild animals come into contact and what we do to overcome these problems. Help us enrich our animals’ homes; visit the large collection of wild cats, our own African Savannah and Tropical House. - presentation (ppt) "Habitats & Inhabitants" - worksheet "Habitat Quest" - student evaluation worksheet - coloring sheet - worksheet Match the Track to the Habitat - children's e-book on chimpanzees 3. Animals of the Greek Forest The Wolf did not eat Little Red Riding Hood and the Griffon vulture does not prey on live sheep. Discover why Greek wildlife should not be feared but be respected and protected. Learn how these animals survive in the Mediterranean landscape, what threats they face and how they can live together with humans, side by side. Watch Vicky, the Otter, swim in her personal pool, our family of Bears forage for fruit and fish, the Wolves eat and play and our rescued Vultures show off their wing span. - General Information on species (ppt) - In the Winter (ppt) - Forest animals (ppt) & notes - Masks and drawing (pdf) - Worksheets (pdf) - Presentation of "Nest box for the Chickadee"
License. Please note that content linked from this page may have different licensing terms. Chapters 7-10: Arithmetic and number theory. Euclid, Greek Eukleides, (flourished c. 300 bce, Alexandria, Egypt), the most prominent mathematician of Greco-Roman antiquity, best known for his treatise on geometry, the Elements. […] The Elements is a textbook rather than a reference book, so it does not cover everything that was known. Our latest articles delivered to your inbox, once a week: Numerous educational institutions recommend us, including Oxford University and Michigan State University and University of Missouri. Around the turn of the twentieth century, Baedeker's Travel Guide dubbed Euclid Avenue the "Showplace of America" for its beautiful elm-lined sidewalks and ornate mansions situated amid lavish gardens. In the only other key reference to Euclid, Pappus of Alexandria (c. 320 AD) briefly mentioned that Apollonius "spent a very long time with the pupils of Euclid at Alexandria, and it was thus that he acquired such a scientific habit of thought" c. 247–222 BC. The few historical references to Euclid were written by Proclus c. 450 AD, eight centuries after Euclid lived. Although best known for its geometric results, the Elements also includes number theory. Older books sometimes confuse him with Euclid of Megara. 1: Books 1-2. Lost works include books on conic sections, logical fallacies, and "porisms." If the ideas seem obvious, that's the point. Likewise, much of Western mathematics has been a series of footnotes to Euclid, either developing his ideas or challenging them. In the Elements, Euclid deduced the theorems of what is now called Euclidean geometry from a small set of axioms. What was Euclid also known as? The scholar Stobaeus lived at about the same time as Proclus. Nineteen references are listed. I have read many articles where Euclid's Elements is linked to Aristotle's logic, but I do not understand, and I can't find any examples explaining how deductive logic (i.e. Around 300 BCE, he ran his own school in Alexandria, Egypt. In other words, how is Aristotle's logic represented in Euclid's Elements?. It is believed Euclid lived only in Alexandria, Egypt. Chapter 1 also includes postulates and "common notions" (axioms). Palmer, N. (2015, October 23). EUCLID, Ohio (WJW) — Euclid Police Chief Scott Meyer says two teens are now hospitalized after being shot during an alleged attempted carjacking. Ancient History Encyclopedia Foundation is a non-profit organization. His education and even birthplace are still in dispute. (That's Euclid's way of saying straight lines exist.) And essentially for about 2,000 years after Euclid-- so this is unbelievable shelf life for a textbook-- people didn't view you as educated if you did not read and understand Euclid's Elements. The first recorded definition of the golden ratio dates back to the period when Greek mathematician Euclid (c. 325–c. Although the apparent citation of Euclid by Archimedes has been judged to be an interpolation by later editors of his works, it is still believed that Euclid wrote his works before Archimedes wrote his. It is said that he was a Greek born in Tyre and lived in Damascus throughout his life. He died in Alexandra Egypt but, no one really knows when he was born (when the exact date he was born.) Euclid of Alexandria lived in 365-300 BC (approximately). In his book about optics, Euclid argued for the same theory of vision as the Christian philosopher St. Augustine. Retrieved from https://www.ancient.eu/Euclid/. He wrote one of the most famous books that is still used today to teach mathematics, Elements, which was well received at its time and also is praised today fo… Most of what we know about ancient Egyptian mathematics comes from the Rhind Papyrus, discovered in the mid-19th century CE and now kept in the British Museum. ); the other is that he taught in Alexandria. If a straight line be cut into equal and unequal segments, the rectangle contained by the unequal segments of the whole together with the square on the straight line between the points of section is equal to the square on the half. The Latest News and Updates in Euclid News brought to you by the team at fox8.com: Cleveland's source for news, weather, Browns, Indians, and Cavs Skip to content Written by N.S. He collected Greek manuscripts that were in danger of being lost. c. 365 - 300 B.C.E. The 17th-century CE Dutch philosopher Baruch de Spinoza modeled his book Ethics on The Elements, using the same format of definitions, postulates, axioms, and proofs. Euclid. . Watch live video as clean up begins from rioters' destruction of downtown … He lived lots of his life in Alexandria, Egypt, and developed many mathematical theories. Palmer, N.S. , Very few original references to Euclid survive, so little is known about his life. Ancient History Encyclopedia Limited is a non-profit company registered in the United Kingdom. Web. We do not know the years or places of his birth and death. oblong, rhombus, rhomboid: What was Euclid's most famous work, and how many books are in it? It has had a lasting influence on the sciences -, especially in mathematics. First English version of Euclid's Elements, 1570, by Charles Thomas-Stanford (Public Domain). , Although many of the results in Elements originated with earlier mathematicians, one of Euclid's accomplishments was to present them in a single, logically coherent framework, making it easy to use and easy to reference, including a system of rigorous mathematical proofs that remains the basis of mathematics 23 centuries later.. Euclid Avenue's "Millionaires' Row" was home to some of the nation's most powerful and influential industrialists, including John D. Rockefeller. He gave some of his own original discoveries, such as the first known proof that there are infinitely many prime numbers. Euclid. First English version of Euclid's Elements, 1570by Charles Thomas-Stanford (Public Domain). Thales even became a celebrity in Egypt because he could see the mathematical principles behind rules for specific problems, then apply the principles to other problems such as determining the height of the pyramids. More recent scholarship suggests a date of 75–125 AD. Common Notion: "Things equal to the same thing are also equal to each other.". O'Connor, John J.; Robertson, Edmund F., "Euclid of Alexandria"; Heath 1956, p. 4; Heath 1981, p. 355. Euclid is a city in Cuyahoga County, Ohio, United States. From ancient times to the late 19th century CE, people considered The Elements as a perfect example of correct reasoning. 20 Dec 2020. O'Connor, John J.; Robertson, Edmund F., "Theon of Alexandria", Oxford University Museum of Natural History, "One of the Oldest Extant Diagrams from Euclid", One of the oldest extant diagrams from Euclid, "NASA Delivers Detectors for ESA's Euclid Spacecraft", Texts on Ancient Mathematics and Mathematical Astronomy, "The elements of geometrie of the most auncient Philosopher Euclide of Megara", Ancient Greek and Hellenistic mathematics, https://en.wikipedia.org/w/index.php?title=Euclid&oldid=994501956, Short description is different from Wikidata, Wikipedia indefinitely semi-protected pages, Articles containing Ancient Greek (to 1453)-language text, Wikipedia articles with BIBSYS identifiers, Wikipedia articles with CANTIC identifiers, Wikipedia articles with CINII identifiers, Wikipedia articles with SELIBR identifiers, Wikipedia articles with SNAC-ID identifiers, Wikipedia articles with SUDOC identifiers, Wikipedia articles with TDVİA identifiers, Wikipedia articles with Trove identifiers, Wikipedia articles with WORLDCATID identifiers, Creative Commons Attribution-ShareAlike License, This page was last edited on 16 December 2020, at 01:26. Their method implies that pi has a value of 3.16, slightly off its true value of 3.14... but close enough for simple engineering. Historical records of Euclid are very scant, and from pieces of government records and... See full answer below. He was active in Alexandria during the reign of Ptolemy I (323–283 BC). When Did Euclid Live? He is most famous for his works in geometry, inventing many of the ways we conceive of space, time, and shapes. One is that he was intermediate in date between the pupils of Plato (d. 347 b.c.) It considers the connection between perfect numbers and Mersenne primes (known as the Euclid–Euler theorem), the infinitude of prime numbers, Euclid's lemma on factorization (which leads to the fundamental theorem of arithmetic on uniqueness of prime factorizations), and the Euclidean algorithm for finding the greatest common divisor of two numbers. Learn euclid with free interactive flashcards. Modern economics has been called "a series of footnotes to Adam Smith," who was the author of The Wealth of Nations (1776 CE). 287 b.c. "Euclid." Some historical references were written by Pappus of Alexandria and Proclus centuries after Euclid’s death (265 BC). Chapters 11-13: Solid geometry. Euclid’s Life. The Papyrus Oxyrhynchus 29 (P. Oxy. As of the 2010 census, the city had a total population of 48,920. Books As of 2006 CE, 960 of the tablets had been deciphered. It is believed that he was a student of Plato. This license lets others remix, tweak, and build upon this content non-commercially, as long as they credit the author and license their new creations under the identical terms. Euclid's other works Some of Euclid's other works are known only because other writers have mentioned them. In the 20th century, the Austrian economist Ludwig von Mises adopted Euclid's axiomatic method to write about economics in his book Human Action. Proclus provides the only reference ascribing the Elements to Euclid. Examples are: Definition: "A point is that which has no part." Ancient History Encyclopedia. We only know about them because other ancient writers refer to them. An Answer Plus a Short History of Geometry. Associations, Committees, Clubs & Youth Programs. and Archimedes (b.ca. It is an inner ring suburb of Cleveland. Where did Euclid live? Please help us create teaching materials on Mesopotamia (including several complete lessons with worksheets, activities, answers, essay questions, and more), which will be free to download for teachers all over the world. For example, to calculate the area of a circle, they made a square whose sides were eight-ninths the length of the circle's diameter. In 2009, Euclid celebrated its bicentennial. 365-275 BC) also known as Euclid of Alexandria, was a Greek mathematician, often referred to as the "Father of Geometry". In The Elements, Euclid collected, organized, and proved geometric ideas that were already used as applied techniques. Euclid's most famous work is his collection of 13 books, dealing with geometry, called The Elements. He was likely born c. 325 BC, although the place and circumstances of both his birth and death are unknown and may only be estimated roughly relative to other people mentioned with him. Euclid of Alexandria (lived c. 300 BCE) systematized ancient Greek and Near Eastern mathematics and geometry. Euclid: Euclid (sometimes called "Euclid of Alexandria") was an ancient Greek mathematician who is largely credited with the development of the mathematical field of geometry. Euclid wanted to base his geometry on ideas so obvious that no one could reasonably doubt them. Euclid. Alexandria, Egypt: What three geometrical definitions did Euclid create? Postulate: "To draw a straight line from any point to any point." Euclid of Alexandria was a Greek Mathematician.He was born in 323 BC. Proclus believes that Euclid is not much younger than these, and that he must have lived during the time of Ptolemy I (c. 367 BC – 282 BC) because he was mentioned by Archimedes. Euclid's works that still exist are The Elements, Data, Division of Figures, Phenomena, and Optics. We're not sure what porisms were. They are said to be " the most studied books apart from the Bible". He told a story about Euclid that has the ring of truth: Someone who had begun to [study] geometry asked Euclid, 'What shall I get by learning these things?' Ancient History Encyclopedia. Modern 'non-Euclidean' geometries describe space over astronomical distances, at near-light speeds, or warped by gravity. Mathematicians usually refer to him simply as "Euclid," but he's sometimes called Euclid of Alexandria to avoid confusion with the Green Socratic philosopher Euclid of Megara. Euclid of Alexandria is considered to be the Father of Geometry. Here's Looking at Euclid: From Counting Ants to Games of Chance - An... Creative Commons Attribution-NonCommercial-ShareAlike. O'Connor, John J.; Robertson, Edmund F., "Euclid of Alexandria"; Struik p. 51 ("their logical structure has influenced scientific thinking perhaps more than any other text in the world"). Euclid discovered that aspects of nature could be described mathematically through a system of geometry he developed. He was born in around 325 BC, was probably educated in Plato’s school in Athens, and he taught mathematics in Alexandria, the great new city of commerce and academia constructed in Egypt on the orders of Alexander the Great during Euclid’s lifetime. "Euclid." in Alexandria, Egypt and lived until about 300 B.C. Fragment of Euclid's Elementsby Jitse Niesen (CC BY). He was active in Alexandria during the reign of Ptolemy I (323–283 BC). Fact 3 His �Elements� is one of the most powerful works in the history of mathematics, considered the chief textbook for mathematics (particularly geometry) from the time of its creation till … The philosopher Proclus of Athens (412-485 CE), who lived seven centuries later, said that Euclid "put together the Elements, collecting many of Eudoxus’s theorems, perfecting many of Theaetetus’s, and bringing to irrefragable demonstration things which were only somewhat loosely proved by his predecessors." The chief tells the FOX 8 I … In the Elements, Euclid deduced … 0 1 2 Euclid did not originate most of the ideas in The Elements. Greece: Where did Euclid teach and live? We do not know the years or places of his birth and death. The ancient Egyptians knew a lot of geometry, but only as applied methods based on testing and experience. He presented geometry as an axiomatic system: Every statement was either an axiom, a postulate, or was proven by clear logical steps from axioms and postulates. The English name Euclid is the anglicized version of the Greek name Εὐκλείδης, which means "renowned, glorious". Except for Euclid and some of his Greek predecessors such as Thales (624-548 BCE), Hippocrates (470-410 BCE), Theaetetus (417-369 BCE), and Eudoxus (408-355 BCE), hardly anyone had tried to figure out why the ideas were true or if they applied in general. Many important later thinkers believed that other subjects might come to share the certainty of geometry if only they followed the same method. 265 BC) described what he called the "extreme and mean ratio". Euclid lived for about 60 years between around 325 and 265 BC. , Proclus introduces Euclid only briefly in his Commentary on the Elements. The term science comes from the Latin word scientia, meaning “knowledge&rdquo... Thales of Miletus (l. c. 585 BCE) is traditionally regarded... An illustration of Euclid of Alexandria, the 4th century BCE mathematician... Euclidâ€™s puzzling parallel postulate - Jeff Dekofsky, The Thirteen Books of the Elements, Vol. Euclid called his slave and said, 'Give him [some money], since he must make gain out of what he learns'. The philosopher Benedict Spinoza even wrote an Eth… The area of the square was close enough to the area of the circle that they could not detect any difference. Euclid's arrival in Alexandria came about ten years after its founding by Alexander the Great, which means he arrived c. 322 BC. His textbook ‘Elements’ remained a highly influential mathematics teaching book until the late 19th Century and is one of the most widely published books in the world. , Because the lack of biographical information is unusual for the period (extensive biographies being available for most significant Greek mathematicians several centuries before and after Euclid), some researchers have proposed that Euclid was not a historical personage, and that his works were written by a team of mathematicians who took the name Euclid from Euclid of Megara (à la Bourbaki). Ancient History Encyclopedia. There are few references to Euclid’s life. He collected important mathematical and geometric knowledge in one book. Ancient Babylonians also knew a lot of applied mathematics, including the Pythagorean theorem. https://www.ancient.eu/Euclid/. The "Elements" defined the mathematical terms number, prime number, composite and perfect number. EUCLID, Ohio (WOIO) - A mother is murdered in front of her young child, now Euclid Police are on the hunt for a killer. Cite This Work Adele, Gail H. Mathematics Teacher, v82 n6 p460-63 Sep 1989. Euclid was born around 365 B.C. The geometrical system described in the Elements was long known simply as geometry, and was considered to be the only geometry possible. Ancient History Encyclopedia, 23 Oct 2015. His Elements is one of the most influential works in the history of mathematics, serving as the main textbook for teaching mathematics (especially geometry) from the time of its publication until the late 19th or early 20th century. During his lifetime, he has written 13 books which are now famous as Euclid Elements. Euclid's On Division, also dealing with plane geometry, is concerned with more general problem Related Content When did Euclid live? And Euclid's Elements, the book itself, was the second most printed book in the Western world after the … This biography is generally believed to be fictitious. The table describes the name and performance of mathematicians from the Babylonians to 1977. He gave definitions, postulates, and axioms. Euclid proved a sequence of theorems that marks the beginning of number theory as a mathematical endeavor versus a numerological one. Euclid was born in Megara, In fact 100 years before the great mathematician, Euclid of Alexandria, there was a Euclid of Megara. Euclid (Ancient Greek: Εὐκλείδης Eukleidēs -- "Good Glory", ca. , A detailed biography of Euclid is given by Arabian authors, mentioning, for example, a birth town of Tyre. Euclid also wrote works on perspective, conic sections, spherical geometry, number theory, and mathematical rigour. Other works are credibly attributed to Euclid, but have been lost. , Euclid died c. 270 BC, presumably in Alexandria. the father of geometry: When was Euclid born? Last modified October 23, 2015. The Elements, 13 Almost nothing is known of Euclid's life. There is no mention of Euclid in the earliest remaining copies of the Elements. He wrote The Elements, the most widely used mathematics and geometry textbook in history. 300 BC), sometimes called Euclid of Alexandria to distinguish him from Euclid of Megara, was a Greek mathematician, often referred to as the "founder of geometry" or the "father of geometry". Archaeological excavations at Nineveh discovered clay tablets with number triplets satisfying the Pythagorean theorem, such as 3-4-5, 5-12-13, and with considerably larger numbers. Palmer, published on 23 October 2015 under the following license: Creative Commons Attribution-NonCommercial-ShareAlike. From his definitions, postulates, and common notions, Euclid deduces the rest of geometry. According to Proclus, Euclid supposedly belonged to Plato's "persuasion" and brought together the Elements, drawing on prior work of Eudoxus of Cnidus and of several pupils of Plato (particularly Theaetetus and Philip of Opus.) He seems to have written a dozen or so books, most of which are now lost. For only $5 per month you can become a member and support our mission to engage people with cultural heritage and to improve history education worldwide. His geometry describes the normal space we see around us. We have also been recommended for educational use by the following publications: Ancient History Encyclopedia Foundation is a non-profit organization registered in Canada. They follow the same logical structure as Elements, with definitions and proved propositions. Although Euclid (Latinized as Euclides) is the most celebrated mathematician of all time, whose name became a synonym for geometry until the twentieth century,1 only two facts of his life are known, and even these are not beyond dispute. The philosopher Proclus of Athens(412-485 CE), who lived seven centuries later, said that Euclid "put together the Elements, collecting many of Eudoxus’s theorems, perfecting many of Theaetetus’s, and bringing to irrefragable demonstration things which were only somewhat loosely pr… Euclid , sometimes called Euclid of Alexandria to distinguish him from Euclid of Megara, was a Greek mathematician, often referred to as the "founder of geometry" or the "father of geometry". 29) is a fragment of the second book of the Elements of Euclid, unearthed by Grenfell and Hunt 1897 in Oxyrhynchus. He was active in Alexandria during the reign of Ptolemy I (323–283 BC). Most of the copies say they are "from the edition of Theon" or the "lectures of Theon", while the text considered to be primary, held by the Vatican, mentions no author. His contribution was fourfold: The Elements has 13 chapters (often called "books"), divided into three main sections: Chapters 1-6: Plane geometry. This article provides a chronological table on the history of geometry. The European Space Agency's (ESA) Euclid spacecraft was named in his honor. Euclid (/ˈjuːklɪd/; Ancient Greek: Εὐκλείδης – Eukleídēs, pronounced [eu̯.kleː.dɛːs]; fl. , The fragment contains the statement of the 5th proposition of Book 2, which in the translation of T. L. Heath reads:. Around 300 BCE, he ran his own school in Alexandria, Egypt. Until recently most scholars would have been content to say that Euclid was older than Archimedes on the ground that Eucl… He is also known as “founder/father of geometry”. Euclid (c. 325 BC – 265 BC) – Greek Mathematician considered the “Father of Geometry”. " This anecdote is questionable since it is similar to a story told about Menaechmus and Alexander the Great. Gordon Geiger, co-owner of Geiger's, calls the damage "unbelievable." , Greek mathematician, inventor of axiomatic geometry. He called axioms "common notions.". Almost nothing is known of Euclid's life. Proclus later retells a story that, when Ptolemy I asked if there was a shorter path to learning geometry than Euclid's Elements, "Euclid replied there is no royal road to geometry. René Descartes, for example, said that if we start with self-evident truths (also called axioms) and then proceed by logically deducing more and more complex truths from these, then there's nothing we couldn't come to know. Most of his days was spent in Alexandria. Why was the city named after euclid? The book Data discusses plane geometry and contains propositions (problems to be demonstrated) in which certain data are given about a figure and from which other data can be figured out. Although Euclid is a famous mathematician, very little is known about his life. Every chapter begins with definitions. He is mentioned by name, though rarely, by other Greek mathematicians from Archimedes (c. 287 BC – c. 212 BC) onward, and is usually referred to as "ὁ στοιχειώτης" ("the author of Elements"). One South Euclid; Pool & Splash Park Information; South Euclid Business Directory; South Euclid Civic Organizations; South Euclid Dining Directory; South Euclid Garden Walk; South Euclid Parks; Schools & Places of Worship; Residents. What country was Euclid born in? Euclid was working in Alexandria during the rule of Ptolemy I (323�283 BC). In addition to the Elements, at least five works of Euclid have survived to the present day. About half of Euclid's works are lost. He seems to have written a dozen or so books, most of which are now lost. Some Rights Reserved (2009-2020) under Creative Commons Attribution-NonCommercial-ShareAlike license unless otherwise noted. More than a thousand editions have been published, making it one of the most popular books after theBible. Palmer, N.S. However, this hypothesis is not well accepted by scholars and there is little evidence in its favor. c. 325 B.C. Euclid's story, although well known, is also something of a mystery. Euclid was a Greek mathematician three centuries before Christ, who taught at the ancient Library of Alexandria and laid out the principles that came to define Euclidean geometry. If he came from Alexandria, he would have known the Serapeum of Alexandria, and the Library of Alexandria, and may have worked there during his time. However, there is no certain evidence if he was the same person as Euclid of Alexandria is often confused with Euclid of Megara, another man who was a philosopher and lived at the time of Plato. 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The electronic sensor used to detect the movement of human being within a certain range of the sensor is called as PIR sensor or passive infrared sensor (approximately have an average value of 10m, but 5m to 12m is the actual detection range of the sensor). Fundamentally, pyroelectric sensors that detect the levels of infrared radiation are used to make PIR sensors. There are different types of sensor and here let us discuss about PIR sensor with dome shaped Fresnel lens. The pin configuration of the PIR sensor is shown in the figure. PIR sensor consists of three pins, ground, signal, and power at the side or bottom. Generally, the PIR sensor power is up to 5V, but, the large size PIR modules operate a relay instead of direct output. It is very simple and easy to interface the sensor with a microcontroller. The output of the PIR is (usually digital output) either low or high. PIR Sensor Circuit The PIR sensor circuit consists of three pins, power supply pin, output signal pin, and ground pin. The PIR sensor circuit is having ceramic substrate and filter window as shown in the figure and also having dome like structure called as Fresnel lens. PIR Sensor Working If once the sensor gets warmed up, then the output remains low until it detects motion. If once it detects the motion, then the output goes high for a couple of seconds and then returns to a normal state or low. This sensor requires settling time, which is characteristically in the range of 10 to 60 seconds. Practical Applications of PIR Sensor PIR sensors have numerous applications in different fields such as automatic switching operation of outdoor lights, lift lobby, common staircases, automatic switching operation of garden lights based on the presence of a human being, for covered parking area, automatic door operating system in shopping malls, and so on
The mountain pygmy-possum has been the focus of active and innovative conservation over the past decade, including wild-wild translocations between populations, predator control and habitat regeneration. In 2013, we trialed the first release of this endangered species from captivity to the wild. The key objectives were to evaluate the survival rate for captive-bred possums and test whether released animals genetically augment the wild population. Eleven possums (six females and five males) bred in captivity at Healesville Sanctuary, Zoos Victoria, plus two wild-born males, were deemed genetically suitable for release to two boulder-fields at Mt Buller, south-eastern Australia, by the Mountain Pygmy-possum State Recovery Team. In captivity, possums were provided with food, habitat features and social interactions to mimic their wild environment as much as possible and were housed in temperature-controlled enclosures that promoted natural hibernation cycles. Released possums were radio-tracked for four weeks to determine survival, reproduction and habitat use. Short-term survival was extremely high, with 6/6 females and 6/7 males re-trapped one month post-release. The remaining male’s collar was found detached (without evidence of predation). Further trapping by field partners monitored the possums over time, with 85% of possums being re-trapped over the following four months. All females produced one to two litters of pouch young within four months of release, with some of their young and at least one of the released females also producing young the following year. Knowledge gained from this trial will help inform future management strategies aimed at securing this species in the wild.
Visual problems in children can affect their physical, intellectual, social and emotional development. Early detection and correction of ocular conditions may enable them in improved academic performance. Clinical Protocol: Screening for uncorrected refractive errors- ocular diseases- Binocular vision anomalies- Colour vision deficiency Our school eye screening model is a comprehensive model that includes not only testing for refractive errors (need for spectacles) but also diagnosis of other ocular problems like squint, cataract, ptosis etc. Those requiring surgical or medical management are referred to the base hospital for further management and free treatment. Apart, we also screen for binocular vision anomalies (working of the muscles of the eye together). As most children complain of headache and eye strain after prolonged reading, we have established that binocular vision anomalies is the common cause and it is present in 30% of school children. This is done for children from class 8-12. Also we assess the response of the lens system in eye making sure all aspects of binocularity is addressed and correlate with their reading activities. Eye exercises (Vision therapy) for these problems in the school premises itself along with the vision screening kit. Colour vision screening is another added protocol. Colour vision defects are common in 8% of boys, whereas it is less prevalent among girls. This screening is crucial considering that many careers like marine engineering, chemical engineering, armed forces and other such services have made normal colour vision mandatory. No child gets a screening for colour vision usually as there is no treatment available. But a counselling on the choice of career they should make is essential for their parents, teacher along with the children. This is also done for children from classes 8-12. Sustenance of care: This model does not stop with the screening alone but continues and sustains a relationship with the school for regular care. Compliance to spectacle wear is monitored on a surprise visit and interventions are planned to improve compliance. Vision Ambassadors: We also train few selected students from the school as “Vision Ambassadors” to perform a basic vision screening and these students would help monitor compliance to the treatment suggested. This improved the ownership among children towards the overall eye health care. - Professional team of Optometrists, Paediatric optometry Fellows and interns of Optometry to offer screening and testing. - Choice of trendy, colourful frames that the children can select on their own - A complete detailed report to the school and the education department - In person distribution of spectacles with counselling to parents and children within 2 weeks of screening - Vision therapy for needy children at the school premises along with the therapy kit - Distribution of Information-Education-Communication materials - Telephone calls/ reminders to parents of referred children who did not bring them to the hospital - Surprise visit to school for assessment of compliance to spectacle wear and referral - Annual follow up of children identified with problems
A montage of Cassini images, taken in four different regions of the spectrum from ultraviolet to near-infrared, demonstrates that there is more to Saturn than meets the eye. The pictures show the effects of absorption and scattering of light at different wavelengths by both atmospheric gas and clouds of differing heights and thicknesses. They also show absorption of light by colored particles mixed with white ammonia clouds in the planet's atmosphere. Contrast has been enhanced to aid visibility of the atmosphere. Cassini's narrow-angle camera took these four images over a period of 20 minutes on April 3, 2004, when the spacecraft was 44.5 million kilometers (27.7 million miles) from the planet. The image scale is approximately 267 kilometers (166 miles) per pixel. All four images show the same face of Saturn. In the upper left image, Saturn is seen in ultraviolet wavelengths (298 nanometers); at upper right, in visible blue wavelengths (440 nanometers); at lower left, in far red wavelengths just beyond the visible-light spectrum (727 nanometers; and at lower right, in near-infrared wavelengths (930 nanometers). The sliver of light seen in the northern hemisphere appears bright in the ultraviolet and blue (top images) and is nearly invisible at longer wavelengths (bottom images). The clouds in this part of the northern hemisphere are deep, and sunlight is illuminating only the cloud-free upper atmosphere. The shorter wavelengths are consequently scattered by the gas and make the illuminated atmosphere bright, while the longer wavelengths are absorbed by methane. Saturn's rings also appear noticeably different from image to image, whose exposure times range from two to 46 seconds. The rings appear dark in the 46-second ultraviolet image because they inherently reflect little light at these wavelengths. The differences at other wavelengths are mostly due to the differences in exposure times. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org . NASA/JPL/Space Science Institute
10 facts about pandas! Find out all about these brilliant bears! Here at National Geographic Kids, we love wonderful wild bears! Join us as we learn about one of nature’s cutest critters in our facts about pandas! Facts about pandas - 1. Giant pandas (often referred to as simply “pandas”) are black and white bears. In the wild, they are found in thick bamboo forests, high up in the mountains of central China – you can check out our cool facts about China, here! - 2. These magnificent mammals are omnivores. But whilst pandas will occasionally eat small animals and fish, bamboo counts for 99 percent of their diet. - 3. Pandas are BIG eaters – every day they fill their tummies for up to 12 hours, shifting up to 12 kilograms of bamboo! - 4. The giant panda’s scientific name is Ailuropoda melanoleuca, which means “black and white cat-foot”. - 5. Giant pandas grow to between 1.2m and 1.5m, and weigh between 75kg and 135kg. Scientists aren’t sure how long pandas live in the wild, but in captivity they live to be around 30 years old. - 6. Baby pandas are born pink and measure about 15cm – that’s about the size of a pencil! They are also born blind and only open their eyes six to eight weeks after birth. - 7. It’s thought that these magnificent mammals are solitary animals, with males and females only coming together briefly to mate. Recent research, however, suggests that giant pandas occasionally meet outside of breeding season, and communicate with each other through scent marks and calls. Did you know that we have a FREE downloadable panda primary resource? Great for teachers, homeschoolers and parents alike! - 8. Family time! Female pandas give birth to one or two cubs every two years. Cubs stay with their mothers for 18 months before venturing off on their own! - 9. Unlike most other bears, pandas do not hibernate. When winter approaches, they head lower down their mountain homes to warmer temperatures, where they continue to chomp away on bamboo! - 10. Sadly, these beautiful bears are endangered, and it’s estimated that only around 1,000 remain in the wild. That’s why we need to do all we can to protect them!
Chunks of rock laced with ingredients for life or early life forms could have traveled among our solar system and others much more frequently than previously thought possible, an international team of researchers including Renu Malhotra in the University of Arizona Lunar and Planetary Laboratory has discovered. The researchers report in the journal Astrobiology that under certain conditions, there is a high probability that life came to Earth – or spread from Earth to other planets – during the solar system's infancy when Earth and its planetary neighbors orbiting other stars would have been close enough to each other to exchange lots of solid material. The findings provide the strongest support yet for "lithopanspermia," the idea that basic life forms are distributed throughout the universe via meteorite-like planetary fragments cast forth by disruptions such as planet and asteroid collisions. Eventually, another planetary system's gravity traps these roaming rocks, which can result in a mingling that transfers any living cargo. “We wanted to know how debris left over from the formation of our solar system can get transported from one planetary system to another,” said Renu Malhotra , a professor of planetary science in the UA's Lunar and Planetary Laboratory “Even today, some of these rocks leak out of the asteroid belt and hit planets,” said Malhotra. “That’s how we get meteorites. Some of them land on other planets, and some get thrown out of the solar system.” “With this study, we wanted to find out what happens to those small rocks that are thrown out and escape the solar system. Where do they go?” Previous research suggested that, typically, those small rocks called meteoroids leave the solar system at high speeds, making the chances of being snagged in the gravitational pull of another object highly unlikely. “Those studies assumed a typical velocity of 5,000 meters per second or more,” said Malhotra. “They neglected the small fraction of material leaving a solar system at speeds slow enough to be captured by other planetary systems.” Using the star cluster in which our sun was born as a model, the team conducted simulations showing that at these lower speeds, the transfer of solid material from one star's planetary system to another could have been far more likely than previously thought, explained first author Edward Belbruno, a mathematician and visiting research collaborator in the department of astrophysical sciences at Princeton University who developed the principles of weak transfer. Weak transfer describes a low-velocity process wherein solid materials meander out of the orbit of one large object and happen into the orbit of another. In this case, the researchers factored in velocities 50 times slower than previous estimates, or about 100 meters per second. The researchers suggest that of all the boulders cast off from our solar system and its closest neighbor, five to 12 out of 10,000 could have been captured by the other. Earlier simulations had suggested chances as slim as one in a million. "Our work says the opposite of most previous work," Belbruno said. "It says that lithopanspermia might have been very likely, and it may be the first paper to demonstrate that. If this mechanism is true, it has implications for life in the universe as a whole. This could have happened anywhere." The team also found that the timing of such an exchange could be compatible with the actual development of the solar system, as well as with the earliest known emergence of life on Earth. The researchers report that the solar system and its nearest planetary-system neighbor could have swapped rocks at least 100 trillion times well before the sun struck out from its native star cluster, moving it out of range of other planetary systems. Furthermore, existing rock evidence shows that basic life forms could indeed date from the sun's birth cluster days – and have been hardy enough to survive an interstellar journey and eventual impact. Co-author Amaya Moro-Martín , who earned her doctorate at the UA in 2004 and is now an astronomer at the Centro de Astrobiología in Spain, said the weak transfer mechanism would have allowed large quantities of solid material to be exchanged among planetary systems, over timescales that could potentially allow the survival of microorganisms embedded in large boulders. Star birth clusters satisfy two requirements for weak transfer, Moro-Martín said. First, the sending and receiving planetary systems must contain a massive planet that captures the passing solid matter in the weak-gravity boundary between itself and its parent star. Earth's solar system qualifies, and several other stars in the sun's birth cluster would too. Second, both planetary systems must have low relative velocities. In the sun's stellar cluster, between 1,000 and 10,000 stars were gravitationally bound to one another for hundreds of millions of years, each with a velocity of no more than a sluggish 1 kilometer per second, Moro-Martín said. The odds of a star capturing solid matter from another planetary system with a star similar to the sun’s mass are 15 in 10,000, the researchers report – probabilities exceeding those under the conditions proposed by previous publications by a factor of 1 billion. To estimate the actual amount of solid matter that could have been exchanged between the sun and its nearest star neighbor, the researchers used data and models pertaining to the movement and formation of asteroids, the Kuiper Belt – the solar system's massive outer ring of asteroids – and the Oort Cloud, a hypothesized collection of comets, ice and other matter about one light year from Earth's sun widely believed to be a primary source of comets and meteorites. The researchers used this data to conclude that during a period of 10 million to 90 million years, anywhere between 100 trillion to 30 quadrillion solid matter objects weighing more than 10 kilograms transferred between the sun and its nearest cluster neighbor. Of these, some 200 billion rocks from early Earth could have been whisked away via weak transfer. For lithopanspermia to happen, however, microorganisms first have to survive the long, radiation-soaked journey through space. Computer simulations published previously by other researchers showed that survival times ranged from 12 million years for a boulder up to 3 centimeters (roughly 1 inch) in diameter, to 500 million years for a solid objects 2.67 meters (nearly 9 feet) across. As for the actual transfer of life, the researchers suggest that roughly 300 million lithopanspermia events could have occurred between our solar system and the closest planetary system. If life arose on Earth shortly after surface water was available, life would have had about 400 million years to journey from the Earth to another habitable world and vice versa before the sun’s star cluster dispersed, the researchers report. Likewise, if life had an early start in other planetary systems, life on Earth may have originated beyond our solar system. “Our study stops when the solid matter is trapped by the second planetary system, but for lithopanspermia to be completed it actually needs to land on a terrestrial planet where life could flourish," Moro-Martín said. "The study of the probability of landing on a terrestrial planet is work that we now know is worth doing because large quantities of solid material originating from the first planetary system may be trapped by the second planetary system, waiting to land on a terrestrial planet. "Our study does not prove lithopanspermia actually took place," Moro-Martín said, "but it indicates that it is an open possibility." The paper, "Chaotic Exchange of Solid Material between Planetary Systems: Implications for Lithopanspermia," was published Sept. 12 by Astrobiology and was supported by grants from NASA, the National Science Foundation and the Ministry of Science and Innovation in Spain.
The digestive system (also known as alimentary system) is a complex system of organs providing mechanical and chemical processing of foot, absorption of nutrients, and excretion of the undigested remains. The digestive system consists of the gastrointestinal tract and accessory organs involved in digestion. The human gastrointestinal tract is about eight to ten metres long, and it includes the following parts: - oral cavity, - small intestine, with the following parts: - large intestine, with the following parts: - ascending colon, - transverse colon, - descending colon, - sigmoid colon, In addition, the digestive system includes salivary glands two major glandular organs - liver, pancreas, as well as the gallbladder and the peritoneum.
To ensure the long-term survival of Pongo tapanuliensis, conservation measures need to be implemented swiftly. Due to the rugged terrain, external threats have been primarily limited to illegal clearing of forests, hunting, killings during crop conflict and trade in orangutans (Wich et al. 2012, Wich et al. 2016). A hydroelectric development has been proposed recently in the area of highest orangutan density, which could impact nearly 10% of P. tapanuliensis’ population. This project might lead to further genetic impoverishment and inbreeding, as it would jeopardize chances of maintaining habitat corridors between the western and eastern range, and smaller nature reserves, all of which maintain small populations of P. tapanuliensis. The Tapanuli Orangutan is also protected by international legislation by default because it is included within the old concept of P. abelii which is listed on CITES Appendix I. For much of the 20th century, orangutans on Sumatra were thought to be restricted to the north and west of Lake Toba, in and around the Leuser Ecosystem. Populations south of Lake Toba were overlooked, even though a 1939 review of the species’ range mentioned that orangutans had been reported in several forest areas in that region (Nederlandsch-Indische Vereeniging tot Natuurbescherming 1939). It was not until 1997 that these isolated orangutan populations were rediscovered (Meijaard 1997, Rijksen and Meijaard 1999). As a consequence of further sightings, published in 2003 (Wich et al. 2003), a study of the southern populations started in 2005 when the Sumatran Orangutan Conservation Programme (SOCP) began a conservation project in the mountainous Batang Toru region with the intent of conserving the orangutan population and their remaining habitat south of Lake Toba. The only known population of Pongo tapanuliensis occurs in the uplands of the Batang Toru Ecosystem, an area of roughly 1,500 km² consisting of three forest blocks, of which 1,022 km² is suitable orangutan habitat (Wich et al. 2016). Pongo tapanuliensis is the least numerous of all great ape species. Pongo tapanuliensis was until relatively recently more widespread, with sightings further south in the lowland peat swamp forests in the Lumut area (Wich et al. 2003) and several nests encountered during a rapid survey in 2010 (G. Fredriksson pers. obs.). The forests in the Lumut area have in recent years almost completely been converted to oil-palm plantations. In 2008, a captive Tapanuli Orangutan was confiscated in Lumut. Observation were also made of a male orangutan in the Dolok Ginjang area, just north of the Batang Toru West forest block in the Adiankoting subdistrict in North Tapanuli, during a human conflict situation where an orangutan was shot at with an air rifle when it was found foraging on durian fruits (G. Fredriksson pers. obs.). Recent surveys in this area did not find any orangutan nests (Nowak et al. unpublished data). A hunting trip report from 1879 described orangutan encounters near the small town of Mantinggi, south of the current population (0°58’ N, 100°0’ E) (Kramm 1879). In 1902, orangutan signs and reports were noted along several small rivers on the south side of the Sibolga Bay, west of Batang Toru (Miller 1903). Unsubstantiated reports suggest that orangutans, presumably P. tapanuliensis, may have occurred even further south in Sumatra in historic periods. A number of museum specimens are claimed to have come from Padang, Palembang and Jambi (Schlegel and Müller 1839–1844, Beccari 1904, Hooijer 1948, Veracini et al. 2010), and an orangutan kill was reported in 1930 near Palembang and along the Musi River toward the base of the Barisan Mountain range (Delmont 1930). These accounts suggest that isolated individuals or small populations of P. tapanuliensis may have survived outside the current range well into the 1900s, although without studying specimens from these areas, we cannot exclude that they could be P. abelii. Despite the distance to the south and their rarity, such reports are perhaps not surprising, as orangutans are long lived and isolated individuals or populations could potentially exist in fragmented landscapes for >50 years, provided that food resources were available and stochastic processes were rare. With a population estimate of fewer than 800 individuals (Wich et al. 2016), Pongo tapanuliensis is the least numerous of all great ape species. Its distribution is separated by around 100 km from the closest population of P. abelii to the north. A combination of small population size and geographic isolation is of particularly high conservation concern, as it may lead to inbreeding depression (Hedrick and Kalinowski 2000) and threaten population persistence (Allendorf et al. 2013). Highlighting this, a recent study (Nater et al. 2017) discovered extensive runs of homozygosity in the genomes of two P. tapanuliensis individuals, pointing at the occurrence of recent inbreeding. Only about 10% of the geographic range is in an area recognized by the World Database of Protected Areas. Another 76% is in Hutan Lindung (Protection Forest), and 14% does not have any 'forest status' in the spatial plans, despite the fact that it consists of rugged primary forest with the highest densities of Tapanuli Orangutans in the Batang Toru Ecosystem (SOCP unpublished data). This roughly translates to 8% of the total distribution located in nationally recognized conservation area (Cagar Alam, Strict Nature Reserve), 78% in Protection Forest (Hutan Lindung), and the remaining 14% of the range is entirely unprotected.
Exact differential equation An exact differential equation is a differential equation that can be solved in the following manner. Suppose you are given an equation of the form: Before we begin solving it, we must first check that the equation is exact. This means that: To find the solution of this equation, we assume that the solution is φ = constant. We can re-write a different form of this equation by substituting and . This yields , which makes sense. to find φ, we integrate M with respect to t and N with respect to y. This will give us two different equations. To find φ , we Go through the example to find φ by integrating, then check that and that any function φ = some constant, when turned into the corresponding dy/dt, satisfies the original equation. Be sure to emphasize that one must check first that To find , first set and . Then manipulate to get and . Integrate both sides, compare the results for , and combine the terms into one equation (for terms that show up in both expressions, only write once in the combined expression.) To solve the expression for , plug into the quadratic formula.
Join Kevin Kelly for an in-depth discussion in this video Choosing appropriate technologies to facilitate interactivity, part of Teaching with Technology. - In an earlier movie on choosing appropriate technologies, I showed you the XYZs, a 3D framework for choosing technologies for sharing content. Now I'll use that framework for choosing content for facilitating activities. I've provided an Exercise File in the Chapter 5 folder called XYZ Activity Framework so you can refer to it during or after this movie. If you jumped straight to this movie, the three dimensions of the framework narrow your choices by answering three common questions. On the x axis, we answer, where are the learners? On the y axis, we answer, when are they learning? On the z axis, we answer, how many learners are there? This framework is described in more detail in the chapter on sharing content with technology. In this movie, we'll use the framework to pick technologies for specific teaching and learning activities. Let's start with some in-class activities. To engage students in small groups during face-to-face class meetings, use presentation apps like Nearpod. Push your slides to every student, as well an engage them in activities, solicit feedback and assess understanding. Use clickers and clicker apps, such as Poll Everywhere. Use Twitter via laptops and mobile devices. You can conduct large class activities, such as back channeling, and Google jockys or small group activities such as Think, Pair, Tweet. Last, use concept map software or apps to ask small groups to show relationships between course concepts, and share each group's work. To interact with students one on one or in small groups at a specific time, but from different locations, consider using online phone services, such as Skype, to conduct virtual office hours or Google apps, such as Google Picasa. You can ask students to take a picture of their math homework with their phone, upload it to Google Picasa so you can write on it while you talk via Skype. To host online class meetings or study sessions at a specific time, use video conferencing and online meeting tools, such as Blackboard Collaborate, Adobe Connect or Zoom. To engage students in collaborative projects that don't require working together at the same time, use collaborative documents, such as Google Docs. To collect student perceptions from the entire class related to course concepts, use timeline software, such as Ntrepid Timestream. Use media-sharing sites, such as Flickr, to ask students to share images of real-world applications of class concepts. Use concept map software to ask students to work together to make connections between class concepts. Use social networking sites, such as Facebook or Google+, to create groups that students can use to ask each other questions about assignments or to prepare for exams. And use wiki tools to create a space for students to work on small group projects together. There are several more quadrants and many more technologies, but the framework provides a way to filter possibilities. Use it when you don't know which tool will meet your teaching and learning needs. Before reviewing another movie, take a minute to answer the following questions for yourself. Are you looking for technology to conduct activities with students in the classroom or for students to interact with each other outside the classroom? Are you looking for technology that students will use to work individually, collaboratively, or both? Are you looking for technology that students will use to participate in activities at a specific time, or whenever they choose? Author Kevin Kelly explains how learning outcomes can be adapted to support technology in the classroom, and guides educators through selecting the appropriate technology for their activity, module, or class. Then he shows how to apply technology in three key areas: finding, creating, and sharing content with students; facilitating classroom activities; and assessing learning inside the classroom or online. - Including technology in your learning outcomes - Applying Universal Design for Learning (UDL) principles - Finding and creating content and instructional materials - Enhancing lectures and presentations with technology - Getting students involved - Facilitating in-class activities - Assessing learning - Teaching effectively online
A conductor refers to a material that contains electrical charges on its surface, allowing electricity to flow through it. Most often, these electrical charges are due to the presence of electrons. A material's degree of conductivity depends on the number of charge carriers present, the amount of charge being carried, and the mobility of the charge carriers. Generally, strong conductors are metals with loosely bound valence electrons that can move freely between atoms. Silver is the strongest conductor out of all known materials. However, because silver is a relatively costly and sought-after material, it is not frequently used for its conductive properties. In cases where an extremely conductive material is essential, copper may be coated with a thin layer of liquid silver. Copper is one of the most frequently used conductors due to its high conductivity combined with its relative abundance and low cost. Because it is also a ductile metal, it can be wound into coils and used to make wires. According to the European Copper Institute, copper is very resistant to corrosion, which also makes it ideal for home wiring. Sciencing Video Vault Along with copper, aluminum is another frequently used conductor. While copper is more conductive, aluminum is more frequently used to make frying pans due to copper's reactivity with acidic foods. In February of 2011, Science Daily announced that aluminum was likely to replace copper in electric and semi-electric vehicles. Aluminum is less dense and cheaper than copper. However, this is still in debate because aluminum has less heat stability and the potential to corrode at a faster rate. It may need to be alloyed with another metal for certain applications. Other Conducting Materials In addition to the strong conductors listed above, other conductors include gold, iron, steel, brass, bronze and mercury. While materials generally fall into the category of being either a conductor or an insulator, some materials are both. According to ScienCentral, semiconductors are materials that are are mostly comprised of atoms that do not have free-moving electrons and therefore, they do not normally conduct electricity. However, some of their atoms do have free-moving electrons, which under certain circumstances, enables them to be conductive.
Class room chemistry: blowing up a balloon with carbon dioxide CO2 Learning about chemical reactions in classroom chemistry: Here the team is blowing up a balloon with carbon dioxide (CO2) made by mixing vinegar and bicarbonate of soda! First a test reaction in a cup – Yes, it definitely reacts and produces a gas! The test reaction of vinegar and sodium bicarbonate Then charge up the balloon with bicarbonate – easier for small hands than large. Charging the balloon with sodium bicarbonate Slip the balloon opening over the top of the vinegar bottle – keeping the bicarbonate at the farthest end of the balloon. Lift the balloon! Next lift up the balloon from the far end allowing the sodium bicarbonate powder to fall down into the vinegar. Balloon inflating with carbon dioxide 1 Now watch as your balloon inflates ‘by itself’ Balloon starts inflating with carbon dioxide 2 Balloon starts inflating with carbon dioxide 3 Explain that vinegar and sodium bicarbonate are reacting together to form carbon dioxide, water and another chemical (sodium acetate). We did it – our carbon dioxide filled balloon! Good work everyone!
Petrified wood occurs when organic material in wood is replaced by inorganic materials, such as minerals. Usually this occurs close to a volcano. The process has taken 215 million years. Our petrified wood comes from Africa. The trunk is sliced in thin elements which are placed on a slab of granite or marble. In this form, we optimize the utilization of this precious geological element by using the minimum possible amount.
Bookkeeping is the recording of financial transactions, and is part of the process of accounting in business. Transactions include purchases, sales, receipts, and payments by an individual person or an organization/corporation. There are several standard methods of bookkeeping, such as the single-entry bookkeeping system and the double-entry bookkeeping system, but, while they may be thought of as “real” bookkeeping, any process that involves the recording of financial transactions is a bookkeeping process. Bookkeeping is usually performed by a bookkeeper. A bookkeeper (or book-keeper) is a person who records the day-to-day financial transactions of a business. He or she is usually responsible for writing the daybooks, which contain records of purchases, sales, receipts, and payments. The bookkeeper is responsible for ensuring that all transactions are recorded in the correct daybook, supplier’s ledger, customer ledger, and general ledger; an accountant can then create reports from the information concerning the financial transactions recorded by the bookkeeper. The bookkeeper brings the books to the trial balance stage: an accountant may prepare the income statement and balance sheet using the trial balance and ledgers prepared by the bookkeeper. The term “waste book” was a term used in colonial America referring to bookkeeping. The purpose was to document daily transactions including receipts and expenditures. This was recorded in chronological order, and the purpose was for temporary use only. The daily transactions would then be recorded in a daybook or account ledger in order to balance an accounts. The name “waste book” comes from the fact that once the waste book’s data were transferred to the actual journal, the waste book could be discarded. The bookkeeping process primarily records the financial effects of transactions. The difference between a manual and any electronic accounting system results from the former’s latency between the recording of a financial transaction and its posting in the relevant account. This delay—absent in electronic accounting systems due to nearly instantaneous posting into relevant accounts—is a basic characteristic of manual systems, thus giving rise to primary books of accounts such as Cash Book, Bank Book, Purchase Book, and Sales Book for recording the immediate effect of a financial transaction. In the normal course of business, a document is produced each time a transaction occurs. Sales and purchases usually have invoices or receipts. Deposit slips are produced when lodgements (deposits) are made to a bank account. Checks (spelled “cheques” in the UK and several other countries) are written to pay money out of the account. Bookkeeping first involves recording the details of all of these source documents into multi-column journals (also known as books of first entry or daybooks). For example, all credit sales are recorded in the sales journal; all cash payments are recorded in the cash payments journal. Each column in a journal normally corresponds to an account. In the single entry system, each transaction is recorded only once. Most individuals who balance their check-book each month are using such a system, and most personal-finance software follows this approach. After a certain period, typically a month, each column in each journal is totalled to give a summary for that period. Using the rules of double-entry, these journal summaries are then transferred to their respective accounts in the ledger, or account book. For example, the entries in the Sales Journal are taken and a debit entry is made in each customer’s account (showing that the customer now owes us money), and a credit entry might be made in the account for “Sale of class 2 widgets” (showing that this activity has generated revenue for us). This process of transferring summaries or individual transactions to the ledger is called posting. Once the posting process is complete, accounts kept using the “T” format undergo balancing, which is simply a process to arrive at the balance of the account. As a partial check that the posting process was done correctly, a working document called an unadjusted trial balance is created. In its simplest form, this is a three-column list. Column One contains the names of those accounts in the ledger which have a non-zero balance. If an account has a debit balance, the balance amount is copied into Column Two (the debit column); if an account has a credit balance, the amount is copied into Column Three (the credit column). The debit column is then totalled, and then the credit column is totalled. The two totals must agree—which is not by chance—because under the double-entry rules, whenever there is a posting, the debits of the posting equal the credits of the posting. If the two totals do not agree, an error has been made, either in the journals or during the posting process. The error must be located and rectified, and the totals of the debit column and the credit column recalculated to check for agreement before any further processing can take place. Once the accounts balance, the accountant makes a number of adjustments and changes the balance amounts of some of the accounts. These adjustments must still obey the double-entry rule: for example, the inventory account and asset account might be changed to bring them into line with the actual numbers counted during a stocktake. At the same time, the expense account associated with usage of inventory is adjusted by an equal and opposite amount. Other adjustments such as posting depreciation and prepayments are also done at this time. This results in a listing called the adjusted trial balance. It is the accounts in this list, and their corresponding debit or credit balances, that are used to prepare the financial statements. Finally financial statements are drawn from the trial balance, which may include: - the income statement, also known as the statement of financial results, profit and loss account, or P&L - the balance sheet, also known as the statement of financial position - the cash flow statement - the statement of retained earnings, also known as the statement of total recognised gains and losses or statement of changes in equity - Entry systems - Two common bookkeeping systems used by businesses and other organizations are the single-entry bookkeeping system and the double-entry bookkeeping system. Single-entry bookkeeping uses only income and expense accounts, recorded primarily in a revenue and expense journal. Single-entry bookkeeping is adequate for many small businesses. Double-entry bookkeeping requires posting (recording) each transaction twice, using debits and credits. The primary bookkeeping record in single-entry bookkeeping is the cash book, which is similar to a checking account (UK: cheque account, current account) register, but allocates the income and expenses to various income and expense accounts. Separate account records are maintained for petty cash, accounts payable and receivable, and other relevant transactions such as inventory and travel expenses. These days, single-entry bookkeeping can be done with DIY bookkeeping software to speed up manual calculations. A double-entry bookkeeping system is a set of rules for recording financial information in a financial accounting system in which every transaction or event changes at least two different nominal ledger accounts. A daybook is a descriptive and chronological (diary-like) record of day-to-day financial transactions also called a book of original entry. The daybook’s details must be entered formally into journals to enable posting to ledgers. - Sales daybook, for recording all the sales invoices. - Sales credits daybook, for recording all the sales credit notes. - Purchases daybook, for recording all the purchase invoices. - Purchases Debits daybook, for recording all the purchase Debit notes. - Cash daybook, usually known as the cash book, for recording all money received as well as money paid out. It may be split into two daybooks: receipts daybook for money received in, and payments daybook for money paid out. - General Journal daybook, for recording journals. Petty cash book A petty cash book is a record of small-value purchases before they are later transferred to the ledger and final accounts; it is maintained by a petty or junior cashier. This type of cash book usually uses the imprest system: a certain amount of money is provided to the petty cashier by the senior cashier. This money is to cater for minor expenditures (hospitality, minor stationery, casual postage, and so on) and is reimbursed periodically on satisfactory explanation of how it was spent. Journals are recorded in the general journal daybook. A journal is a formal and chronological record of financial transactions before their values are accounted for in the general ledger as debits and credits. A company can maintain one journal for all transactions, or keep several journals based on similar activity (e.g., sales, cash receipts, revenue, etc.), making transactions easier to summarize and reference later. For every debit journal entry recorded, there must be an equivalent credit journal entry to maintain a balanced accounting equation. A ledger is a record of accounts. These accounts are recorded separately, showing their beginning/ending balance. A journal lists financial transactions in chronological order, without showing their balance but showing how much is going to be charged in each account. A ledger takes each financial transaction from the journal and records it into the corresponding account for every transaction listed. The ledger also sums up the total of every account, which is transferred into the balance sheet and the income statement. There are three different kinds of ledgers that deal with book-keeping: - Sales ledger, which deals mostly with the accounts receivable account. This ledger consists of the records of the financial transactions made by customers to the business. - Purchase ledger is the record of the purchasing transactions a company does; it goes hand in hand with the Accounts Payable account. - General ledger, representing the original five, main accounts: assets, liabilities, equity, income, and expenses. Abbreviations used in bookkeeping A/C – Account Acc – Account A/R – Accounts receivable A/P – Accounts payable B/S – Balance sheet c/d – Carried down b/d – Brought down c/f – Carried forward b/f – Brought forward Dr – Debit Cr – Credit G/L – General ledger; (or N/L – nominal ledger) P&L – Profit and loss; (or I/S – income statement) P/R – Payroll PP&E – Property, plant and equipment TB – Trial Balance GST – Goods and services tax VAT – Value added tax CST – Central sale tax TDS – Tax deducted at source AMT – Alternate minimum tax EBITDA – Earnings before interest, taxes, depreciation and amortisation EBDTA – Earnings before depreciation, taxes and amortisation EBT – Earnings before tax EAT – Earnings after tax PAT – Profit after tax PBT – Profit before tax Depr – Depreciation Dep – Depreciation CPO – Cash paid out CP – Cash Payment Chart of accounts A chart of accounts is a list of the accounts codes that can be identified with numeric, alphabetical, or alphanumeric codes allowing the account to be located in the general ledger. The equity section of the chart of accounts is based on the fact that the legal structure of the entity is of a particular legal type. Possibilities include sole trader, partnership, trust, and company. Computerized bookkeeping removes many of the paper “books” that are used to record the financial transactions of an entity—instead, relational databases take their place, but they still typically enforce the double-entry bookkeeping system and methodology.
How a child sees color is a function of both the color receptors in the retina of the eye as well as specialized neurons in the occipital lobe of the brain. Color vision deficiency (sometimes called “color blindness”) can be caused by issues with the receptor cells of the eye’s retina or by damage to the color processing centers in the brain caused by stroke, traumatic brain injury, or seizures. Certain types of anti-epileptic drugs can also cause issues with color vision as well. Brain-based color blindness is called cerebral achromatopsia. Usually both sides of the brain would have to be affected. While no research shows that hemispherectomy, TPO, or occipital lobectomy is correlated with cerebral achromatopsia, a history of seizures, stroke, cortical dysplasia, or anti-epileptic drug use can cause it. Assessments for color vision should be regularly performed on a child after these procedures as appropriate. Challenges from color vision deficiency, if recognized, are able to be addressed easily in the classroom. If unrecognized, however, it may be frustrating for the teacher and the child.
A parasitic plant is a plant that derives some or all of its nutritional requirement from another living plant. They make up about 1% of angiosperms and are in almost every biome in the world. All parasitic plants have modified roots, called haustoria, which penetrate the host plants, connecting them to the conductive system – either the xylem, the phloem, or both. For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and Orobanche connect only to the phloem of the host (phloem-feeding). This provides them with the ability to extract water and nutrients from the host. Parasitic plants are classified depending on where the parasitic plant latches onto the host and the amount of nutrients it requires. Some parasitic plants are able to locate their host plants by detecting chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plant in approximately 20 families of flowering plants are known. Parasitic plants occur in multiple plant families, indicating that the evolution is polyphyletic. Some families are comprised mostly of parasitic representatives such as Balanophoraceae, while other families have only a few representatives. One example is the North American Monotropa uniflora (Indian pipe or corpse plant) which is a member of the heath family, Ericaceae, better known for its members blueberries, cranberries, and rhododendrons. Parasitic plants are characterized as follows: - 1a. Obligate parasite – a parasite that cannot complete its life cycle without a host. - 1b. Facultative parasite – a parasite that can complete its life cycle independent of a host. - 2a. Stem parasite – a parasite that attaches to the host stem. - 2b. Root parasite – a parasite that attaches to the host root. - 3a. Hemiparasite – a plant parasitic under natural conditions, but photosynthetic to some degree. Hemiparasites may just obtain water and mineral nutrients from the host plant; many obtain at least part of their organic nutrients from the host as well. - 3b. Holoparasite - a parasitic plant that derives all of its fixed carbon from the host plant. Commonly lacking chlorophyll, holoparasites are often colors other than green. For hemiparasites, one from each of the three sets of terms can be applied to the same species, e.g. - Nuytsia floribunda (Western Australian Christmas tree) is an obligate root hemiparasite. - Rhinanthus (e.g. Yellow rattle) is a facultative root hemiparasite. - Mistletoe is an obligate stem hemiparasite. Holoparasites are always obligate so only two terms are needed, e.g. Plants usually considered holoparasites include broomrape, dodder, Rafflesia, and the Hydnoraceae. Plants usually considered hemiparasites include Castilleja, mistletoe, Western Australian Christmas tree, and yellow rattle. Evolution of parasitic behaviorEdit Parasitic behavior evolved in angiosperms roughly 12-13 times independently, a classic example of convergent evolution. Roughly 1% of all angiosperm species are parasitic, with a large degree of host dependence. The taxonomic family Orobanchaceae (encompassing the genera Tryphysaria, Striga, and Orobanche) is the only family that contains both holoparasitic and hemiparasitic species, making it a model group for studying the evolutionary rise of parasitism. The remaining groups contain only hemiparasites or holoparasites. The evolutionary event which gave rise to parasitism in plants was the development of haustoria. The first, most ancestral, haustoria are thought to be similar to that of the facultative hemiparasites within Tryphysaria, lateral haustoria develop along the surface of the roots in these species. Later evolution led to the development of terminal or primary haustoria at the tip of the juvenile radicle, seen in obligate hemiparasitic species within Striga. Lastly, obligate holoparasitic behavior originated with the loss of the photosynthetic process, seen in the genus Orobanche. To maximize resources, many parasitic plants have evolved 'self-incompatibility', to avoid parasitizing themselves. Others such as Triphysaria usually avoid parasitizing other members of their species, but some parasitic plants have no such limits. The albino redwood is a mutant Sequoia sempervirens that produces no chlorophyll; they live on sugars from neighbouring trees, usually the parent tree from which they have grown (via a somatic mutation). Parasitic plants germinate in a variety of ways. These means can either be chemical or mechanical and the means used by seeds often depends on whether or not the parasites are root parasites or stem parasites. Most parasitic plants need to germinate in close proximity to their host plants because their seeds are limited in the amount of resources necessary to survive without nutrients from their host plants. Resources are limited due in part to the fact that most parasitic plants are not able to use autotrophic nutrition to establish the early stages of seeding. Root parasitic plant seeds tend to use chemical cues for germination. In order for germination to occur, seeds need to be fairly close to their host plant. For example, the seeds of witchweed (Striga asiatica) need to be within 3 to 4 millimeters (mm) of its host in order to pick up chemical signals in the soil to signal germination. This range is important because Striga asiatica will only grow about 4 mm after germination. Chemical compound cues sensed by parasitic plant seeds are from host plant root exudates that are leached in close proximity from the host’s root system into the surrounding soil. These chemical cues are a variety of compounds that are unstable and rapidly degraded in soil and are present within a radius of a few meters of the plant exuding them. Parasitic plants germinate and follow a concentration gradient of these compounds in the soil toward the host plants if close enough. These compounds are called strigolactones. Strigolactone stimulates ethylene biosynthesis in seeds causing them to germinate. There are a variety of chemical germination stimulants. Strigol was the first of the germination stimulants to be isolated. It was isolated from a non-host cotton plant and has been found in true host plants such as corn and millets. The stimulants are usually plant specific, examples of other germination stimulants include sorgolactone from sorghum, orobanchol and alectrol from red clover, and 5-deoxystrigol from Lotus japonicus. Strigolactones are apocarotenoids that are produced via the carotenoid pathway of plants. Strigolactones and mycorrhizal fungi have a relationship in which Strigolactone also cues the growth of mycorrhizal fungus. Stem parasitic plants, unlike most root parasites, germinate using the resources inside their endosperms and are able to survive for some time. For example, the dodders (Cuscuta spp.) drop their seeds to the ground; these may remain dormant for up to five years before they find a host plant nearby. Using the resources in the seed endosperm, dodder is able to germinate. Once germinated, the plant has 6 days to find and establish a connection with its host plant before its resources run out. Dodder seeds germinate above ground and then the plant sends out stems in search of its host plant reaching up to 6 cm before it dies. It is believed that the plant uses two methods of finding a host. The stem detects its host plant's scent and orients itself in that direction. Scientists used volatiles from tomato plants (α-pinene, β-myrcene, and β-phellandrene) to test the reaction of C. pentagona and found that the stem orients itself in the direction of the odor. Some studies suggest that by using light reflecting from nearby plants dodders are able to select host with higher sugar because of the levels of chlorophyll in the leaves. Once the dodder finds its host, it wraps itself around the host plants stem. Using adventitious roots, the dodder taps into the host plant's stem with a haustorium, an absorptive organ within the host plant vascular tissue. Dodder makes several of these connections with the host as it moves up the plant. There are several methods of seed dispersal, but all the strategies aim to put the seed in direct contact with, or within a critical distance of, the host. - The Cuscuta seedling can live for 3–7 weeks and extend out 35 cm in search of the host before it dies. This is because the Cuscuta seed is large and has stored nutrients to sustain its life. This is also useful for seeds that get digested by animals and excreted out. - Mistletoe use a sticky seed for dispersal. The seed sticks to nearby animals and birds and then comes into direct contact with the host. - Arceuthobium seeds have a similarly sticky seed as the mistletoe but they do not rely on animals and birds, they mainly disperse by fruit explosiveness. Once the seed makes contact with the host rain water can help position the seed into a suitable position. - Some seeds detect and respond to chemical stimulations produced in the host’s roots and start to grow towards the host. Obstacles of attaching to a hostEdit The parasitic plant has many obstacles to overcome in order to attach to the host. Distance from the host and stored nutrients are only some of the problems, the host's defenses are an obstacle to overcome itself. The first hurdle is penetrating the host, the host has systems to reinforce the cell wall by protein cross-linking so that it stops the parasitic progress at the cortex of the host's roots. The second hurdle is the host's ability to secrete germination inhibitors. This prevents germination of the parasitic seed. The third hurdle is the host's ability to create a toxic environment for where the parasitic plant attaches to. The host secretes phenolic compounds into the apoplast the creates a toxic environment for the parasitic plant eventually killing it. The fourth hurdle is the host's ability to ruin the tubercle using gums and gels or injecting toxins into the tubercle. Some parasitic plants are generalists and parasitize many different species, even several different species at once. Dodder (Cassytha spp., Cuscuta spp.) and red rattle (Odontites vernus) are generalist parasites. Other parasitic plants are specialists that parasitize a few or even just one species. Beech drops (Epifagus virginiana) is a root holoparasite only on American beech (Fagus grandifolia). Rafflesia is a holoparasite on the vine Tetrastigma. Plants such as Pterospora become parasites of mycorrhizal fungi. There is evidence that parasites also practice self-discrimination, species of Tryphysaria experience reduced haustorium development in the presence of other Tryphysaria. Although, the mechanism for self-discrimination in parasites is not yet known. Aquatic parasitic plantsEdit Parasitism also evolved within aquatic species of plants and algae. Parasitic marine plants are described as benthic, meaning that they are sedentary or attached to another structure. Plants and algae that grow on the host plant, using it as an attachment point are given the designation epiphytic (epilithic is the name given to plants/algae that use rocks or boulders for attachment), while not necessarily parasitic, some species occur in high correlation with a certain host species, suggesting that they rely on the host plant in some way or another. In contrast, endophytic plants and algae grow inside their host plant, these have a wide range of host dependence from obligate holoparasites to facultative hemiparasites. Marine parasites occur as a higher proportion of marine flora in temperate rather than tropical waters. While no full explanation for this is available, many of the potential host plants such as kelp and other macroscopic brown algae are generally restricted to temperate areas. Roughly 75% of parasitic red algae infect hosts in the same taxonomic family as themselves, these are given the designation adelphoparasites. Other marine parasites, deemed endozoic, are parasites of marine invertebrates (molluscs, flatworms, sponges) and can be either holoparasitic or hemiparasitic, some retaining the ability to photosynthesize after infection. Species within Orobanchaceae are some of the most economically destructive species on Earth. Species of Striga alone are estimated to cost billions of dollars a year in crop yield loss annually, infesting over 50 million hectares of cultivated land within sub-Saharan Africa alone. Striga can infest both grasses and grains, including corn, rice and Sorghum, undoubtedly some of the most important food crops. Orobanche also threatens a wide range of important crops, including peas, chickpeas, tomatoes, carrots, lettuce, and varieties of the genus Brassica (e.g. cabbage and broccoli). Yield loss from Orobanche can reach 100% and has caused farmers in some regions of the world to abandon certain staple crops and begin importing others as an alternative. Much research has been devoted to the control of Orobanche and Striga species, which are even more devastating in developing areas of the world, though no method has been found to be entirely successful. - Mistletoes cause economic damage to forest and ornamental trees. - Rafflesia arnoldii produces the world's largest flowers at about one meter in diameter. It is a tourist attraction in its native habitat. - Sandalwood trees (Santalum species) have many important cultural uses and their fragrant oils have high commercial value. - Indian paintbrush (Castilleja linariaefolia) is the state flower of Wyoming. - The oak mistletoe (Phoradendron serotinum) is the floral emblem of Oklahoma. - A few other parasitic plants are occasionally cultivated for their attractive flowers, such as Nuytsia and broomrape. - Parasitic plants are important in research, especially on the loss of photosynthesis during evolution. - A few dozen parasitic plants have occasionally been used as food by people. - Western Australian Christmas tree (Nuytsia floribunda) sometimes damages underground cables. It mistakes the cables for host roots and tries to parasitize them using its sclerenchymatic guillotine. Some parasitic plants are destructive while some have positive influences in their communities. Some parasitic plants damage invasive species more than native species. This results in the reduced damage of invasive species in the community. Plants parasitic on fungiEdit About 400 species of flowering plants, plus one gymnosperm (Parasitaxus usta), are parasitic on mycorrhizal fungi. This effectively gives these plants the ability to become associated with many of the other plants around them. They are termed myco-heterotrophs. Some myco-heterotrophs are Indian pipe (Monotropa uniflora), snow plant (Sarcodes sanguinea), underground orchid (Rhizanthella gardneri), bird's nest orchid (Neottia nidus-avis), and sugarstick (Allotropa virgata). Within the taxonomic family Ericaceae, known for extensive mycorrhizal relationships, there are the Monotropoids. The Monotropoids include the genera Monotropa, Monotropsis, and Pterospora among others. Myco-heterotrophic behavior is commonly accompanied by the loss of chlorophyll. - Heide-Jørgensen, Henning (2008-06-19). Parasitic flowering plants. BRILL. doi:10.1163/ej.9789004167506.i-438. ISBN 9789047433590. - Heide-Jørgensen, Henning S. (2008). Parasitic flowering plants. Leiden: Brill. ISBN 978-9004167506.[page needed] - Nickrent, D. L. and Musselman, L. J. 2004. Introduction to Parasitic Flowering Plants. The Plant Health Instructor. doi:10.1094/PHI-I-2004-0330-01 - Westwood, James H., John I. Yoder, Michael P. Timko and Claude W. Depamphilis. "The Evolution of Parasitism in Plants." Trends in Plant Science 15.4 (2010) 227-35. Web. - Stienstra, T. (11 October 2007). "It's no snow job - handful of redwoods are rare albinos". San Francisco Chronicle. Retrieved December 6, 2010. - Krieger, L. M. (2010-11-28). "Albino redwoods hold scientific mystery". San Jose Mercury News. Retrieved 2012-11-23. - "A Creepy Monster of the Forest: The Albino, Vampiric Redwood Tree". Discover Magazine Discoblog. Retrieved 2012-11-23. Cite magazine requires - Scott, P. 2008. Physiology and behavior of plants: parasitic plants. John Wiley & sons pp. 103–112. - Runyon, J. Tooker, J. Mescher, M. De Moraes, C. 2009. Parasitic plants in agriculture: Chemical ecology of germination and host-plant location as targets for sustainable control: A review. Sustainable Agriculture Reviews 1. pp. 123-136. - Schneeweiss, G. 2007. Correlated evolution of life history and host range in the nonphotosynthetic parasitic flowering plants Orobanche and Phelipanche (Orobanchaceae). Journal Compilation. European Society for Evolutionary Biology. 20 471-478. - Lesica, P. 2010. Dodder: Hardly Doddering. Kelseya Newsletter of Montana Native Plant Society. Vol 23. 2, 6 - Walters, D. (2010). Plant Defense Warding off attack by pathogens, herbivores and parasitic plants. Hoboken: Wiley. - Dring, M. J. The Biology of Marine Plants. London: E. Arnold, 1982. Print. - Landa, B. B.; Navas-Cortés, J. A.; Castillo, P.; Vovlas, N.; Pujadas-Salvà, A. J.; Jiménez-Díaz, R. M. (2006-08-01). "First Report of Broomrape (Orobanche crenata) Infecting Lettuce in Southern Spain". Plant Disease. 90 (8): 1112–1112. doi:10.1094/PD-90-1112B. ISSN 0191-2917. - "Parasitic Plant Food". parasiticplants.siu.edu. - Sclerenchymatic guillotine in the haustorium of Nuytsia floribunda Archived 2006-07-26 at the Wayback Machine - Song, Wenjing; Jin, Zexin; Li, Junmin (April 6, 2012). "Do Native Parasitic Plants Cause More Damage to Exotic Invasive Hosts Than Native Non-Invasive Hosts? An Implication for Biocontrol". PLOS ONE. 7 (4): e34577. doi:10.1371/journal.pone.0034577. PMC 3321012. PMID 22493703 – via PLoS Journals. - O'Neill, Alexander; Rana, Santosh (2017-07-16). "An ethnobotanical analysis of parasitic plants (Parijibi) in the Nepal Himalaya". Journal of Ethnobiology and Ethnomedicine. 12 (14). doi:10.1186/s13002-016-0086-y. PMC 4765049. - Judd, Walter S., Christopher Campbell, and Elizabeth A. Kellogg. Plant Systematics: A Phylogenetic Approach. Sunderland, MA: Sinauer Associates, 2008. Print. - Joel D.M. et al. Eds.(2013) Parasitic Orobanchaceae: Parasitic Mechanisms and Control Strategies. Springer, Heidelberg - Digital Atlas of Cuscuta (Convolvulaceae) - The Parasitic Plant Connection - The Strange and Wonderful Myco-heterotrophs - Parasitic Flowering Plants - The Mistletoe Center - Parasitic Plants Biology Study Guide - Nickrent, Daniel L. 2002. Parasitic plants of the world. - The International Parasitic Plant Society: Photo gallery - Calladine, Ainsley and Pate, John S. 2000. Haustorial structure and functioning of the root hemiparastic tree Nuytsia floribunda (Labill.) R.Br. and water relationships with its hosts. Annals of Botany 85: 723-731. - Milius, Susan. 2000. Botany under the mistletoe: Twisters, spitters, and other flowery thoughts for romantic moments. Science News 158: 411. - Hibberd, Julian M. and Jeschke, W. Dieter. 2001. Solute flux into parasitic plants. Journal of Experimental Botany 52: 2043-2049.
On this page... The electric currents produced by some species of fishes, such as the Numbfish and torpedo rays are generated in cells called electrocytes. When an electrocyte is stimulated, a movement of ions (electrically charged atoms) across the cell membrane results in an electric discharge. The electrocytes of most 'electric fishes' are modified muscle cells. Electrocytes are usually arranged in columns within electric organs. This arrangement increases the electrical output, much like a row of batteries placed end to end. The electric organs of the torpedo rays contain about 45 columns of around 700 electrocytes. Electrical discharges escape through the dorsal surface of the fish. This is because the dorsal surface of both the electric organ and the body have less resistance than the surrounding tissues. Torpedo rays can generate an electrical potential of 20 to 50 volts. Reports exist of fishermen who have received severe electric shocks from handling this fish. There are a number of families that contain 'electric fishes'. Examples include the naked-back knifefishes (gymnotids) of South America, the elephantfishes (mormyrids) of Africa and the South American mochokid catfishes. The South American knifefishes (electrophorids) can generate pulses of over 500 volts. - Helfman, G.S., Collette, B.B. & D.E. Facey. 1997. The Diversity of Fishes. Blackwell Science. Pp. 528.
How Did Lullabies Develop? Putting a crying baby to sleep is hard as any parent likely knows. This has been an age old problem that is evident from a long history of parents attempting to put their children to sleep using song or music as an aid. The history of this starts soon after recorded history began and it is clear the problem of getting children to sleep has been going on for many cultures across time. Early History of the Lullaby Lullabies, undoubtedly, have been around since prehistoric periods. Some scientists suggest lullabies evolved as humans had to multitask and try to get their babies to sleep while also moving in the landscape and needing their hands to be free for other activities. Whatever the reason, we know getting babies to sleep is an ancient problem. The earliest lullabies recorded are from Babylonia, in modern day southern Iraq, where the lullabies are not only songs to help babies sleep but they have characteristics we may find somewhat menacing (Figure 1). There are a number of lullabies from Babylonian; one of the works mention that the baby has cried and is waking up and disturbing the house god who becomes angry with the baby so baby should go back to sleep. Other lullabies from Babylonia were even darker, with threats that the baby would be eaten. While this may sound harsh to us, we should keep in mind of course many lullabies, including our own, have dark undertones such as death or pain caused to the child. Lullabies, with their melancholy rhythm, often have dark undertones in many cultures and that has stayed relatively consistent from their origin. Lullabies were also used as a basis to create magic spells used by Babylonians to help ward evil. So it may have been that saying bad or harmful things was intended to do the opposite, which was to protect the baby from evil spirits. Even in some modern cultures today, curses that ward bad spirits are said using often dark or menacing themes. In Egypt, in a mid-second millennium BCE lullaby, called Magical Lullaby, the lyrics talk about protecting a child from evil spirits. Spells in Egypt involved some spell recitation, ritual, and a magician to be involved; however, lullabies seem to be one type of spell or magic that even normal people could practice. Thus, lullabies may have been seen as a type of spell one attempts to not only put baby to sleep but also protect baby from evil in the night. It was also important to cast the spell properly so lullabies were important for their words of protection as well as the tunes or rhythm they carried. In fact, it may have been the evil spirits that were responsible in making a baby cry so the soothing voice helped protect with that protection putting a baby to sleep. In the Greco-Roman world, similarly lullabies often had negative connotation and were equated or incorporated with magic or spells that the singer would seemingly try to induce to help protect babies. Night would have been seen as potentially a very vulnerable period for a baby and songs would help sooth a baby but also the lyrics were intended to act as spells to help protect a baby from the darkness, which was equated with harmful things that may inflict a young baby. Scholars have, in fact, suggested that lullabies were effectively spells against evil spirits and the soothing sounds were seen as evidence that such spells may have helped babies sleep and avoid the harm that night may cause on a child. During the Medieval and early modern period, it is likely many lullabies we know, such as Rock a Bye Baby and Highland Fairy Lullaby developed. Interestingly, many themes we see in the earliest lullabies remained (Figure 2). As with early societies, fear of the dark and its potential evils on a child seem to prevail in the words of most lullabies. The songs themselves are soothing but lyrics regarding danger, death, and even babies being stolen by thieves are common lyrics in not only the lullabies we know but also those that have been recovered from historical texts. The origin of lullabies such as Rock a Bye Baby are generally unknown; one theory has been that this lullaby originated from observations of Native Americans using tree branches to suspend cradles from. The fear of branches breaking and a baby falling from a tree is possibly reflected by this observation. We also see more themes of animals, such as counting or singing about sheep, in lullabies that developed in Europe. Cross cultural comparisons of lullabies also indicates a fear of the dark and unknown is a common theme in lullabies. For instance, in Iceland Bíum Bíum Bambaló, which has also been sung recently by an Icelandic band, is a terrifying lullaby about a face lurking outside and looking at the window. Fear of what is waiting for baby and with the baby possibly taken if the baby goes outside is a key theme. Even in the New World, lullabies developed to be menacing in their lyrics. For instance, Dodo Titit is a Caribbean lullaby that talks about a crab eating a baby. In Brazil, the lullaby Nana Nenê is about an alligator named Cuca that might get the baby if he or she stays noisy or cries. In Indonesia, an old lullaby of uncertain date reflects a roaming giant on the island that searches for crying babies. Interestingly, in Japan, rather than scary themes, lullabies are often more melancholy, reflecting a mother longing or missing her child. Lullabies such as Itsuki reflects a mother missing her child as she is away, although even here there is fear in the lullaby. In this case, the fear is if the mother dies then the dilemma might be who would take care of the baby. In Malaysia, no harm happens to the baby but baby chicks seem to die in the lyrics during a count down of numbers. Overall, we see a kind of sad or depressing but often frightening theme to lullabies. This also could reflect the melancholy nature of many tunes. In the United States, Hush Little Baby is perhaps among the best known lullabies that developed in the early history of the United States in the southern part of the country. Here, however, the lyrics are not frightful but promise reward for the baby if he or she just goes to sleep. Nevertheless, even here accidents and problems with things breaking seems to happen. The Modern Lullaby Many modern lullabies, of course, are based of their ancient or older counterparts, with themes often focused on fear, lurking dark creatures, or even death. However, studies do also show that lullabies in the past and modern period have beats that do help babies calm their hearts and that a song in a quiet tone with humming often has the effect of relaxing muscles and reducing blood pressure. Lullabies that have been composed recently often do not have the same melancholy or depressing nature of earlier works, although sometimes they do, while a modern rhythm and tunes accompany these works. Works such as Azure Ray have lyrics about not being able to sleep, but the tune appears to be more happy. Even old lullabies such as Rock a Bye Baby or Hush Little Baby have been adapted with often less melancholy beats. Many parents today have been using more upbeat modern songs and either modifying them or simply playing them at a lower level to get their babies to sleep. However, some sleep therapist and doctors do not think all of these works might be appropriate. Recent research does suggest having a more melancholy beat and rhythm helps with sleep. There might be something about those old lullabies then, even if their lyrics are frightful or depressing, in that they generally create the type of sounds that help put babies to sleep more easily and also help relax babies so that their sleep is more efficient and beneficial. Lullabies are more ancient than recorded history but even within recorded history they are evident from some of the earliest periods. From the earliest lullabies recorded in Mesopotamia and Egypt, songs were frightful and often full of frightening demons or gods that could eat or terrify anyone, including babies. Such themes continued and many early lullabies were probably prayers or forms of magic sayings that were intended to help ward evil spirits away from babies, which were seen as active at night. Even more recent lullabies, such as the popular Rock a Bye Baby, is full of terror and potential pitfalls for baby. Only in recent periods do we see more upbeat lullabies; however, some medical scientists question if such lullabies are as effective and potentially melancholy tones and sounds might be more useful in calming babies' minds and hearts as they fall into sleep. - For more on some of the earliest lullabies, such as from Egypt and Mesopotamia, see: Marek, D., 2007. Singing: the first art. Scarecrow Press, Lanham, Md. - For more on Greco-Roman lullabies, see: Frankfurter, D., 2015. The Great, the Little, and the Authoritative Tradition in Magic of the Ancient World. Archiv für Religionsgeschichte 16. https://doi.org/10.1515/arege-2014-0004 - For more on origins of some well-known lullabies in the English-speaking and Western world, see: Van der Walt, T., Fairer-Wessels, F., Inggs, J. (Eds.), 2004. Change and renewal in children’s literature, Contributions to the study of world literature. Praeger, Westport, Conn. - For more on cross-cultural comparisons and reasons for given lullabies lyrics and tunes, see: Achté, K., Fagerström, R., Pentikäinen, J., Farberow, N.L., 1990. Themes of Death and Violence in Lullabies of Different Countries. Omega (Westport) 20, 193–204. https://doi.org/10.2190/A7YP-TJ3C-M9C1-JY45 - For more on how lullabies affect our mental state, see: Hellberg, D. 2015. Rhythm, Evolution and Neuroscience in Lullabies and Poetry. Association for the Study of Ethical Behavior/Evolutionary Biology in Literature 11 (1)
QUANTUM SPEED LIMIT MAY PUT BRAKES ON QUANTUM COMPUTERS Over the past five decades, standard computer processors have gotten increasingly faster. In recent years, however, the limits to that technology have become clear: Chip components can only get so small, and be packed only so closely together, before they overlap or short-circuit. If companies are to continue building ever-faster computers, something will need to change. One key hope for the future of increasingly fast computing is my own field, quantum physics. Quantum computers are expected to be much faster than anything the information age has developed so far. But my recent research has revealed that quantum computers will have limits of their own – and has suggested ways to figure out what those limits are. The limits of understanding To physicists, we humans live in what is called the “classical” world. Most people just call it “the world,” and have come to understand physics intuitively: Throwing a ball sends it up and then back down in a predictable arc, for instance. Even in more complex situations, people tend to have an unconscious understanding of how things work. Most people largely grasp that a car works by burning gasoline in an internal combustion engine (or extracting stored electricity from a battery), to produce energy that is transferred through gears and axles to turn tires, which push against the road to move the car forward. Under the laws of classical physics, there are theoretical limits to these processes. But they are unrealistically high: For instance, we know that a car can never go faster than the speed of light. And no matter how much fuel is on the planet, or how much roadway or how strong the construction methods, no car will get close to going even 10 percent of the speed of light. People never really encounter the actual physical limits of the world, but they exist, and with proper research, physicists can identify them. Until recently, though, scholars only had a rather vague idea that quantum physics had limits too, but didn’t know how to figure out how they might apply in the real world. Physicists trace the history of quantum theory back to 1927, when German physicist Werner Heisenberg showed that the classical methods did not work for very small objects, those roughly the size of individual atoms. When someone throws a ball, for instance, it’s easy to determine exactly where the ball is, and how fast it’s moving. But as Heisenberg showed, that’s not true for atoms and subatomic particles. Instead, an observer can see either where it is or how fast it’s moving – but not both at the exact same time. This is an uncomfortable realization: Even from the moment Heisenberg explained his idea, Albert Einstein (among others) was uneasy with it. It is important to realize that this “quantum uncertainty” is not a shortcoming of measurement equipment or engineering, but rather how our brains work. We have evolved to be so used to how the “classical world” works that the actual physical mechanisms of the “quantum world” are simply beyond our ability to fully grasp. Entering the quantum world If an object in the quantum world travels from one location to another, researchers can’t measure exactly when it has left nor when it will arrive. The limits of physics impose a tiny delay on detecting it. So no matter how quickly the movement actually happens, it won’t be detected until slightly later. (The lengths of time here are incredibly tiny – quadrillionths of a second – but add up over trillions of computer calculations.) That delay effectively slows down the potential speed of a quantum computation – it imposes what we call the “quantum speed limit.” Over the last few years, research, to which my group has contributed significantly, has shown how this quantum speed limit is determined under different conditions, such as using different types of materials in different magnetic and electric fields. For each of these situations, the quantum speed limit is a little higher or a little lower. To everyone’s big surprise, we even found that sometimes unexpected factors can help speed things up, at times, in counterintuitive ways. To understand this situation, it might be useful to imagine a particle moving through water: The particle displaces water molecules as it moves. And after the particle has moved on, the water molecules quickly flow back where they were, leaving no trace behind of the particle’s passage. Now imagine that same particle traveling through honey. Honey has a higher viscosity than water – it’s thicker and flows more slowly – so the honey particles will take longer to move back after the particle moves on. But in the quantum world, the returning flow of honey can build up pressure that propels the quantum particle forward. This extra acceleration can make a quantum particle’s speed limit different from what an observer might otherwise expect. Designing quantum computers As researchers understand more about this quantum speed limit, it will affect how quantum computer processors are designed. Just as engineers figured out how to shrink the size of transistors and pack them more closely together on a classical computer chip, they’ll need some clever innovation to build the fastest possible quantum systems, operating as close as possible to the ultimate speed limit. There’s a lot for researchers like me to explore. It’s not clear whether the quantum speed limit is so high it’s unattainable – like the car that will never even get close to the speed of light. And we don’t fully understand how unexpected elements in the environment – like the honey in the example – can help to speed up quantum processes. As technologies based on quantum physics become more common, we’ll need to find out more about where the limits of quantum physics are, and how to engineer systems that take the best advantage of what we know.
Carpenter Bees (Xylocopa spp.) This hexapod (six-legged) insect is a bee in the subfamily Xylocoinae of either the genus Ceratina or Xylocopa that makes its nest in wood or plant stems. The Life of Carpenter Bees Along with bumble bee queens, carpenter bees (genus Xylocopa) are the largest native bees in the United States. There are numerous species of carpenter bees that inhabit a broad range of ecosystems from tropical to subtropical to temperate. In the United States carpenters bees can be found across the southern United States from Arizona to Florida and in the eastern United States, north to New York. These gentle giants get their name from their life history habits of excavating precisely rounded galleries inside wood. Using their broad, strong mandibles (jaws), they chew into dead but non-decayed limbs or trunks of standing dead trees. Some species, like the eastern Xylocopa virginica, occasionally take up residence in fence posts or structural timbers, especially redwood, and become a minor nuisance. Inside their rounded branched galleries, they form pollen/nectar loaves upon which they lay their giant eggs (up to 15 mm long). The female forms partitions between each egg cell by mixing sawdust and her saliva together. These partition walls are very similar to particle board! Carpenter bees are long lived, up to three years and there can be one or two generations per year. Often newly hatched daughters, live together in their nest with their mother. Biologists using observation nests or X-ray imaging techniques have observed returning foragers feeding other nest mates. These observations have led some entomologists to consider carpenter bees primitively social. However, unlike honey bees and bumble bees there are no queen or worker castes, only individual males and females. In our vegetable and flower gardens, carpenter bees are generalists and may be found foraging on a number of different species. They, like bumblebees are early morning foragers. Carpenter bees land on flower blossoms they become living tuning forks. Using their powerful thoracic muscles carpenter bees sonicate the dry pollen grains out of the flower’s anthers. This type of pollen gathering is called “buzz pollination.” Carpenter bees are excellent pollinators of eggplant, tomato and other vegetables and flowers. From time to time carpenter bees are quite ingenious in their foraging for nectar. On flowers such as salvias, penstemons, and other long, tubular flowers the carpenter bee, due to its large size, is unable to enter the flower opening. Instead they become nectar robbers. Using their mouthparts they cut a slit at the base of corolla and steal away with the nectar without having pollinated the flower. A widespread western US species, Xylocopa varipuncta, has an unusual mating system. Its green-eyed golden males (the females are all black) have huge perfume glands in their thoraces. Territorial males take up positions in non-flowering plants near other males. As a group (lek) they actively release their rose-scented blend of chemicals. Females are attracted from downwind and choose a male with which to mate.
Located in Upper Egypt about six miles (10 km) from the Nile River, the site of Abydos played a pivotal role in ancient Egyptian religious life. The earliest kings of Egypt, including those from the first dynasty of Egypt’s history (3000-2890 B.C.), appear to have been buried at Abydos. Their tombs and funerary enclosures may have been a first step on an ancient architectural journey that would see the Great Pyramids constructed centuries later. In later times, Abydos would become a cult center for Osiris, god of the underworld. A temple dedicated to him flourished at Abydos, and every year a great procession was held that would see an image of Osiris carried from his temple to a tomb the Egyptians believed to be his (it actually belonged to a first dynasty king named Djer), and back, to great fanfare. "There's a really neat reference on some of the Middle Kingdom (4,000 to 3,600 years ago) material to hearing the sound of jubilation," archaeologist Mary-Ann Pouls Wegner told LiveScience in an interview on new discoveries at the site. Her team excavates in an area the ancient Egyptians called the “Terrace of the Great God,” which contains a series of private and royal chapels that were built lining this processional route. Archaeologist Josef Wegner, in an article written in the Oxford Encyclopedia of Ancient Egypt (Oxford University Press, 2001) estimates that Abydos covers about 5 square miles (8 square km). He notes that while many discoveries have been made, much of the site is still unexplored. “The greater part of the site, however, remains concealedbeneath the sand, a fact recognized in the Arabic name of the modern town: Arabah el-Madfunah (‘the buried Arabah’).” Early tombs – Umm el Qa’ab Archaeologists know that the kings of Egypt’s first dynasty (3000-2890 B.C.) and the last two of the second dynasty (ended 2686 B.C.) had tombs at Abydos and were likely buried there. In addition to a burial chamber for their bodies, the rulers were provided with provisions for the afterlife. “First dynasty tombs were provided with large-scale and multi-chambered storage facilities, sometimes in or around the burial chamber, sometimes separate,” writes archaeologist David O’Connor in his book Abydos: Egypt’s First Pharaohs and the Cult of Osiris (Thames and Hudson, 2009). O’Connor also notes that the first dynasty tombs were provided with “subsidiary burials” (sometimes numbering in the hundreds) of people who may have been sacrificed. Just to the north of the royal tombs are cemeteries B and U, which hold tombs that predate the first dynasty, a period referred to as the “pre-dynastic” by Egyptologists. It’s been argued that some of the pre-dynastic tombs at Abydos are those of “proto-kings” who controlled all or a large part of Egypt. How Egypt became unified, and when, is a matter of debate among Egyptologists, and O’Connor notes that it is difficult to determine which of these tombs at Abydos were for kings and which were for elite members of society. One tomb that would appear to be for a ruler is referred to by researchers as “Uj” and was excavated by Günter Dreyer. Excavators found evidence for a wooden shrine above the burial chamber and a small ivory scepter, which could have been a symbol of royalty. Inscribed objects found at the tomb show early examples of Egyptian writing (there is a debate over exactly how to read them). Surrounding the burial chamber was a storage complex that, O’Connor notes, would have held “hundreds of pots filled with foods and drinks,” leaving the person buried there, like the later first dynasty kings, well-provisioned for the afterlife. “[T]hree of the chambers in fact had once been filled with wine jars – locally made imitations of pottery typical of Southern Canaan or Palestine, equivalent to some 4,500 liters,” O’Connor writes, “indeed a royal send off!” Enclosures and grave boats About one mile (1.5 km) to the north of the royal tombs is an enigmatic series of mud brick enclosures dedicated to kings (and in one case a queen) believed buried at Abydos. Oriented northwest to southeast, each enclosure is surrounded by massive walls and contains a chapel. What the enclosure monuments were used for is a mystery. O’Connor notes that eight of the enclosures belong to rulers from the first dynasty (three of which belong to king “Aha” and one to queen Merneith) with an additional pair belonging to the later two kings of the second dynasty. He argues that there are likely more enclosures waiting to be discovered. O’Connor also notes that, like the tombs, the first dynasty enclosures were also provided with burials of people who may have been sacrificed. They too sometimes number in the hundreds. The largest enclosure belongs to King Khasekhemwy of the second dynasty (it didn’t have sacrifices). O’Connor notes that the structure is about 438 feet (134 meters) by 255 feet (78 meters) with its walls originally rising 36 feet (11 meters) high with entranceways on all four sides. In modern times Khasekhemwy’s enclosure has been given the name “Shunet el-Zebib,” which means “raisin magazine” or “storehouse of raisins” (although that was not its original purpose). When O’Connor’s team examined Khasekhemwy’s chapel, located within the enclosure, they found that the southwest portion contained a “labyrinthine complex of chambers” and there was a small room where “traces of incense burning and libations” were found. Northeast of Khasekhemwy’s enclosure, at a junction between King Djer’s enclosure and the “western mastaba,” are a series of 12 “boat graves” each of which contain a full-size wooden boat that would have served a ritual purpose. O’Connor notes that some of them have an “irregularly shaped rock” that may have functioned as an anchor. The boats would have been deposited at the same time but it’s not known which king built them. Boats played an important role in Egyptian religion and full-size examples have also been found at the Great Pyramids among other mortuary sites. “Verbal and visual imagery in Egyptian mortuary contexts often involves boats and ships, which in toto comprise a vast flotilla in which deities, long-dead kings and deceased Egyptians sail through eternity,” O’Connor writes. Temple of Osiris Starting in the Middle Kingdom (4,000 to 3,600 years ago), Abydos became a cult center for Osiris, the god of the underworld. A series of temples were built for him near the “Terrace of the Great God.” Archaeologists have had a difficult time identifying the exact location of the temple site. Between 2002 and 2004, researchers from the Yale-Pennsylvania Institute of Fine Arts expedition discovered two architectural layers from buildings that date from the reigns of kings Nectanebo I and II (about 2,400 years ago) and from the 18th dynasty (around 3,500 years ago). The ceiling of the Nectanebo temple appears to have been decorated with stars carved in relief. “Although not fully excavated, work at the site indicates that perhaps earlier temples might lie below the two phases already discovered,” writes researcher Michelle Marlar in her 2009 doctoral thesis. The last royal pyramid About 3,500 years ago the last royal pyramid built by the Egyptians was constructed at Abydos by Ahmose, the founder of Egypt’s 18th dynasty. A warrior king, he was known for driving the Hyksos, a group originally from Canaan, out of Egypt. His pyramid, perhaps never completed, is now a 32-foot-tall (10 meters) ruin. Even today, at its reduced height, you still get an excellent view while standing on top of it. “The vista from the top of Ahmose’s pyramid is a commanding one, as it surveys the nearby cultivated fields at the edge of the Nile floodplain, as well as the limestone cliffs a kilometer away that mark the start of the plateau of the Sahara desert,” writes archaeologist Stephen Harvey, who leads a project exploring the pyramid and nearby structures, in a 2003 University of Chicago Oriental Institute report. Researcher Mark Lehner estimates that the pyramid originally measured 172 feet (53 meters) square in antiquity, relatively small compared to the Great Pyramids. “Two intact courses of casing stone survived at the eastern base when explored by Arthur Mace at the turn of the century, from which he estimated its angle as 60 (degrees)” writes Lehner in his book The Complete Pyramids (Thames and Hudson, 1997). A pyramid temple nearby has yielded the fragments of decoration including scenes showing the king defeating the Hyksos. To the south an inscribed stela indicates that a pyramid with enclosure was built for Queen Tetisheri, the king’s grandmother. A magnetometry survey carried out by Harvey’s team backs this ancient account up revealing that there is a 300-by-230-foot (90 by 70 meters) “enclosure wall of brick” lying under the desert, waiting to be explored. Temple of Seti I Abydos has many monuments and the Temple of Seti I (known to the Egyptians as a “house of millions of years”) is one of the best preserved. Built about 3,200 years ago, Seti I (also spelled Sety) was a king who fought campaigns in the Levant, flexing Egypt’s military muscle. Archaeologist Dieter Arnold writes in the Encyclopedia of Ancient Egyptian Architecture (I.B. Tauris, 2003) that the main temple building, constructed of limestone, measures 183 by 515 feet (56 by 157 meters) and is located within a brick enclosure. “The temple rises in terraces along the slope of the desert. On the bottom terrace is a man-made lake with a quay, behind which stands the first pylon with royal statue pillars at its rear,” writes Arnold. After passing through two hypostyle halls the visitor comes across seven barque (boat) shrines. One is dedicated to the king Seti I and the others to the gods Ptah, Re-Horakhty, Amun-Re, Osiris, Isis and Horus. O’Connor estimates that each chapel is 135 square feet (12.6 square meters), with a vaulted ceiling 19 feet (5.8 meters) above the ground. “In each chapel was originally housed a boat-shaped palanquin used, as elsewhere, to carry an image of the relevant deity during the processional rituals,” O’Connor writes. One of the most enigmatic structures at Abydos, known to us as the Osireion, is located behind the temple. The main room, as it survives today, has a rocky megalithic look and Arnold notes that a 420-foot (128 meters) passageway leads up to it. It may have served as a tomb for “Osiris-Seti,” a depiction of Seti as Osiris. “The structure of the main hall is fantastical and consists of an island surrounded by a deep moat upon which rested the (now lost) sarcophagus of Osiris-Sety,” writes Arnold. The ceiling of the room was 23 feet (7 meters) across and was “supported on two rows of five granite pillars, weighing 55 tonnes each.” It was a truly massive structure located in an ancient site that incorporates thousands of years of ancient Egyptian history and religious tradition. — Owen Jarus, LiveScience Contributor
Make a Clock! You thought this day would never come, but guess what, it’s time! Time for your child to make a clock to help them learn to tell time, that is. Mastering this skill can seem hard at first, but with hands-on practice, students strengthen their understanding of how clocks work. Here’s a fun activity that lets kids create a clock of their own, and then see the importance of time in real-world events, like a soccer game! What You Need: - Old frisbee, or a thick paper plate - Scissors or a drill - Poster board or heavy paper - Paper fasteners (available at any stationary store) - Circle-shaped stickers What You Do: - Start by making a small hole in the center (With a plate, you can use scissors. With a frisbee, you’ll need to use a drill). Let your child know he’s going to make his very own clock and that the frisbee or paper plate will serve as the clock face. If you have an analog watch or clock somewhere in the house, bring it to the table to use as a model. - Ask your child to place one sticker at the top of the “clock face” and one directly opposite, on the bottom. With the marker, have him write the number 12 on the top sticker and the number 6 on the bottom sticker. Now ask him to place one sticker on each side, halfway in between the top and bottom. He should write 3 on the right-hand sticker, and 9 on the left-hand sticker. Then, referring your analog clock as a model, ask him to fill in the other numbers on the clock using the stickers and his marker. - Now it’s time for the clock hands! Using the poster board, cut two arrows—a longer one for the minute hand, and a shorter one for the hour hand. Pierce the ends of the arrows with the paper fastener, slide it through the hole in the center of your clock face, and secure it at the back. - Pick a day of the week and, with your child’s help, create a list of his activities. This might include soccer practice, a violin lesson, going to school, a playdate, a shopping trip with grandma…or just time spent eating a snack. Next to each entry, write the time the activity begins, rounding to the nearest half hour. - Make it concrete! Help your child identify the hour hand and the minute hand on the clock face. Remind her that the hour hand shows the hour and the minute hand shows the minutes. Now, make sure she knows which hand of the clock is longer (the minute hand) and which hand of the clock is shorter (the hour hand). Pick an activity and find its time on the clock. Start with the activities that begin on the hour and then move to the activities that are on the half hour. - If your child is having trouble, move the hands around the clock, naming each hour as you go. Then give your kid a go at it. Not quite there yet? Don’t worry. Telling time always becomes easier with practice…and time of course!
The Hubble Space Telescope has captured detailed observations of the dwarf galaxy NGC 2366. While it lacks the elegant spiral arms of many larger galaxies, NGC 2366 is home to a bright, star-forming nebula and is close enough for astronomers to discern its individual stars. The starry mist streaking across this image obtained by the NASA/ESA Hubble Space Telescope is the central part of the dwarf galaxy known as NGC 2366. The most obvious feature in this galaxy is a large nebula visible in the upper-right part of the image, an object listed just a few entries prior in the New General Catalogue as NGC 2363. The interconnected objects of NGC 2366 and NGC 2363 are located about 10 million light-years away in the constellation of Camelopardalis (the Giraffe). As a dwarf galaxy, NGC 2366's size is in the same ballpark as the two main satellite galaxies of our Milky Way, named the Large and Small Magellanic Clouds. Like the Magellanic clouds, NGC 2366's lack of well-defined structure leads astronomers to further classify it as an irregular galaxy. Although NGC 2366 might be small by the standards of galaxies, many of its stars are not, and the galaxy is home to numerous gigantic blue stars. The blue dots scattered throughout the galaxy speak to the burst of star formation that the galaxy has undergone in recent cosmic time. A new generation of these stellar titans has lit up the nebula NGC 2363. In gas-rich star-forming regions, the ultraviolet radiation from young, big, blue stars excites the hydrogen gas, making it glow. NGC 2363, as well as other, smaller patches seen throughout Hubble's image, serve as the latest formation sites for stellar giants. This image was produced from two adjacent fields observed by Hubble's Advanced Camera for Surveys. The field of view is approximately 5.5 arcminutes across, which is equivalent to a little over a fifth of the diameter of the full Moon. Although this is comparatively large by the standard of Hubble's images, NGC 2366 is much too faint to observe with the naked eye. The Daily Galaxy via ESA/Hubble Information Center Image credit: NASA & ESA View Today's Hot Tech News Video from IDG -Publishers of PC World, MacWorld, and Computerworld--Top Right of Page To launch the video click on the Start Arrow. Our thanks for your support! It allows us to bring you the news daily about the discoveries, people and events changing our planet and our knowledge of the Universe.
Potato Experiments For Kids First: The potato battery Zinc and copper in an electrolyte generate electricity for a light-emitting diode. That’s what you need in this potato experiments: - 3 potatoes - 3 Cent Coins - 3 screws and washers made of zinc (from the hardware store or from Dad’s tool box) - 4 cables (cable or crocodile wire, insulation at the ends) - 1 LED (this time without the resistor!) - 1 knife Only once the potatoes are cut flat on one side – then they are better. Then each potato into two opposite slits are cut. In the right slot in each one cent coin is in the left or bolt washer. When metal components must lie far apart and should not touch. Now the potatoes as in the image shown in series. When connecting, make sure that the potatoes are so aligned as shown and will always create a connection between zinc and copper. When you connect the LED note that LEDs are polarized components. The longer pin must be connected to the coin. Can not generate much electricity your home-built battery – but for an LED that consumes very little energy, it is enough. The circuit is closed the potato battery, a chemical reaction takes place between the two metals, copper and zinc and the juice of the potato. Due to the chemical reaction, the electrons begin to flow through the cables. Why do they do that? Zinc and copper are different, “noble”. If two such different metals brought into the solution of an electrolyte (the potato), they turn into electrodes – ie in a positive and a negative pole. Because the zinc atoms bind their electrons tightly, less than copper atoms, are the electrons from zinc to copper. And this electron flow is nothing more than Current. Alternatively you can use instead of a potato and a lemon or an apple. After trying to throw the potatoes – they are no longer suitable for consumption! Potato Experiments For Kids Second: Myth “crackling potato” – voltage generation with different metals In this experiment we need a piece of zinc (eg, a strip has been cut from a piece of zinc metal) and a piece of copper, this can be a 1 or 2 cent coin. The coin and the piece of zinc be put into a potato. Now be attached to the coin and the piece of zinc and held a cable to the terminals of an earphone. You can rustle it in earphones to hear clearly and crack, the proof that rests on the two metals a voltage. We measure the voltage with a multimeter, we note that about 0.8 – 0.9V voltage can be generated. This as a “crackling potato” experiment is known as an apple or other fruit. The point is not that a potato or a piece of apple between the zinc and copper coins were fixed, but that an electrically conductive fluid between the two metals is different. For the proof we have even a meter (a digital voltmeter) connected to both ends of the metal and kept in tap water. Here we already measured 0.69 V, we give more salt in the water increases the voltage to about 0.73V. Even a finger of our hands, placed on two metals generates a voltage (about 0.5V). Potato Experiments For Kids: Why here creates an electrical voltage? Both the zinc and the copper ions enter into the solution (water, “potato juice”, body fluid) from, so these are the zinc zinc ions, copper ions in copper up. When zinc but go more ions into the solution. The ions are electrically charged positively, electrons are back with a negative electrical charge. Therefore, the negative electrically charged piece of zinc than the piece of copper, an electrical voltage is established, we can measure. If you join now both pieces with an electrical conductor, the excess electrons move from the zinc to copper, a current flows. This is for example through the earphones and be audible pops and crackles, by opening the contacts to the handset and close repeatedly.
North East - Local Species FloraMixed species eucalypt forest, varying from Red Stringybark on the drier sites to Blue Gum in the gullies and low lying areas, thrive in an environment that experiences significant seasonal variations in climate. However it is this very same forest environment that enables the region to support 2,000 species of plants and over 450 species of animals. FaunaMost commonly seen native animals include kangaroos, swamp wallabies, echidnas, wombats and several species of possums and gliders. The Long-footed Potoroo and Mountain Pygmy Possum also live in the forests of the north east but are unlikely to be seen. Interestingly, the echidna is an unusual native mammal related to the platypus, both of which are the only egg laying mammals in the world. The echidna, once mature, has a diet consisting predominately of ants, and has large, strong claws for digging and a protective covering of spines which are actually modified hairs. The endangered Long-footed Potoroo was previously known only from East Gippsland and parts of NSW until the 80's when it was discovered in the north east. The Department of Environment and Primary Industries is actively working to assist the recovery of this species. DEPI has identified 12 areas for their protection called Special Management Areas. Eight of these areas burnt in the 2003 bushfires. Some of the threats to these ground-dwelling mammals are the loss of habitat and predation by foxes. A predator baiting program has been instigated as one of the Bushfire Recovery Projects and the Department of Primary Industries is assisting with the implementation of the baiting. An ongoing monitoring program will be used to assess the status of the populations, determine the effectiveness of this work and refine management actions. Restricted solely to the alpine and subalpine areas of Victoria's North East, the Mountain Pygmy Possum was thought to be extinct prior to 1966. The Mountain Pygmy Possum, whilst the largest of the pygmy possum family, weighs only about 45g and can fit easily into the palm of a hand.
(This article has been reproduced from the Center for Scientific Creation. The original article can be found here.) upiter, Saturn, and Neptune each radiate away more than twice the heat energy they receive from the Sun.[a] Uranus[b] and Venus[c] also radiate too much heat. Calculations show that it is very unlikely that this energy comes from nuclear fusion,[d] radioactive decay, gravitational contraction, or phase changese within those planets. This suggests that these planets have not existed long enough to cool off.[f] a – H. H. Aumann and C. M. Gillespie Jr., “The Internal Powers and Effective Temperatures of Jupiter and Saturn,” The Astrophysical Journal, Vol. 157, July 1969, pp. L69–L72. - “Jupiter radiates into space rather more than twice the energy it receives from space.” G. H. A. Cole, The Structure of Planets (New York: Crane, Russak & Co., Inc., 1978), p. 114. - M. Mitchell Waldrop, “The Puzzle That Is Saturn,” Science, 18 September 1981, p. 1351. - Jonathan Eberhart, “Neptune’s Inner Warmth,” Science News, Vol. 112, 12 November 1977, p. 316. b – Ibid. c – “The Mystery of Venus’ Internal Heat,” New Scientist, Vol. 88, 13 November 1980, p. 437. d – To initiate nuclear fusion, a body must be at least ten times as massive as Jupiter. [See Andrew P. Ingersoll, “Jupiter and Saturn,” Scientific American, Vol. 245, December 1981, p. 92.] e – Ingersoll and others once proposed that Saturn and Jupiter could generate internal heat if their helium gas liquefied or their liquid hydrogen solidified. Neither is possible, because each planet’s temperature greatly exceeds the critical temperatures of helium and hydrogen. (The critical temperature of a particular gas is that temperature above which no amount of pressure can squeeze it into a liquid or solid.) Even if the temperature were cold enough for gases to liquefy, what could initiate nucleation? When I mentioned this in a private conversation with Ingersoll in December 1981, he quickly acknowledged his error. f – Paul M. Steidl, “The Solar System: An Assessment of Recent Evidence—Planets, Comets, and Asteroids,” Design and Origins in Astronomy, editor George Mulfinger Jr. (Norcross, Georgia: Creation Research Society Books, 1983), pp. 87, 91, 100. - Jupiter would have rapidly cooled to its present temperature, even if it had been an unreasonably hot 20,000 kelvins when it formed. Evolutionary models require too much time. [See Edwin V. Bishop and Wendell C. DeMarcus, “Thermal Histories of Jupiter Models,” Icarus, Vol. 12, May 1970, pp. 317–330.] (This article was taken from the book, In the Beginning by Dr. Walt Brown. The book can be purchased from the Center for Scientific Creation. The original article can be found online here. For more information about Dr. Walt Brown, click here).
As Europeans bask in what is a raw of their warmest seasons on record, it’s almost possible to believe in the beneficence of climate change – even if in the Czech Republic and neighboring Slovakia, it is rousing brown bears out of their hibernation early. But basking in the glow of global warming is misguided for two fundamental reasons. The first is that it views the effects of rising temperatures from a temperate part of the world, which has room to absorb rises and falls in temperature, rather than from areas with more extreme – and hence more vulnerable – weather systems. Second, it is absurdly short-termist. The warmer winters of today’s Europe are just the beginning of a centuries’ long process, one that virtually every scientist on record warns will have the same effect on the planetary global system as it is having on Europe’s brown bears. Shaken out of its own natural cycles, the weather is set to become inexorably hotter, more unpredictable and more destructive as the century progresses. Africa and the Arctic Under Threat The dramatic effects of climate change are most clearly evident in areas of the world with more extreme weather conditions. Two regions present graphic illustrations of this: the Arctic and sub-Saharan Africa. The Arctic and southern Africa are, literally, poles apart, yet the effects of global warming in both regions are already evident, and are set to worsen considerably in the second half of the 21st century, with potentially far reaching effects, both within these areas and for the rest of the world. The recent Arctic Climate Impact Assessment (ACIA) report, released in November 2004, reveals just how far the Arctic is under threat. The ACIA report was compiled for the Arctic Council by an international team of 300 researchers, and summarizes four years of research in the region. The Arctic Council is comprised of the eight nations with Arctic territories: the US, Canada, Denmark, Finland, Iceland, Norway, Russia and Sweden, and the report represents the most comprehensive survey of climate change in the region to date. Its findings make for disturbing reading. The report confirms that global warming in the Arctic has already had an impact: over the past 50 years, average winter temperatures in Alaska, western Canada, and eastern Russia have risen as much as 4oC. Over the next century, temperatures are projected to rise by up to 7oC. The report confirms that the northern ice cap is warming at twice the rate of the rest of the world. This is because warming at the northern pole is enhanced by ‘positive feedback’. Where landmass is covered by snow and ice, 80% to 90% of solar radiation is reflected back into space. But when these white surfaces disappear, more solar radiation is absorbed by the underlying land or sea as heat. This heat, in turn, melts more snow and ice. At the same time, the air in the Arctic is much drier than air at lower latitudes, so less energy is used up in evaporating water, leaving more as heat. Researchers used models developed by the Intergovernmental Panel on Climate Change (ICC) to plot possible effects of such rapid warming, and found the effects are likely to be extensive. According to the average of the five models used, the Arctic will lose 50 percent to 60 percent of its ice distribution by 2100. One model predicts that by 2070, the Arctic will be so warm it will no longer have any ice in the summer. The impact of this warming on the traditional inhabitants of the region, adapted as they are to ice and snow, is likely to be highly destructive. The retreat of sea ice, the report says, “is very likely to have devastating consequences for polar bears, ice-living seals, and local people for whom these animals are a primary food source.” Moreover, increases in glacial melt and river runoff add more water to the oceans, raising sea levels and possibly slowing the currents that bring heat from the tropics to the poles. Calculations by scientists at the Hadley Centre indicate that rapid Arctic warming of less than 3oC could start a runaway melting of the Greenland ice sheet that will eventually raise sea levels worldwide by seven meters. The report also highlights potentially devastating problems associated with the release of methane and carbon dioxide as permafrost thaws and tundra decomposes. Methane is a highly potent greenhouse gas, and there is enough methane locked up in the Siberian tundra to raise global temperatures to unsustainable levels. If the Arctic is a vast – and vulnerable – ecological region, so too is Africa. Yet, Africa is susceptible to the inexorable march of climate change, not because it is so cold, but because it is so hot. Moreover, many African countries are the poorest in the world; hence their capacity to marshal resources to monitor and mitigate the effects of climate change is minimal. As a result, agricultural production and biodiversity are likely to suffer major consequences as the effects of global warming gather pace on the continent. The temperature across Africa has risen by approximately 0.7oC over the twentieth century. Yet the rate of this increase is set to rise rapidly; climate change scenarios for Africa indicate future warming across the continent ranging from 0.2°C (0.36°F) per decade to more than 0.5°C (0.9°F) per decade. Sea levels are also projected to rise by 15 to 95 centimeters (6 to 37 inches) by 2100. Although Africa is typified by a series of microclimates, with the particular effects of climate change variable and unpredictable, general trends indicate less rainfall, greater aridity, increased desertification and greater vulnerability to drought. The impacts of these changes will be felt most powerfully in the agricultural sector. Agriculture in low latitude developing countries is especially vulnerable to climate change for two reasons. The first is because the climates of many of these countries are already too hot, so increased warming will have an adverse effect on crop productivity. The second is because agriculture and agro-ecological systems are the most important economic sectors in most African countries, providing the livelihood of up to 70 percent of the population. Moreover, much agriculture is not capital and technology intensive, which means there is little capacity to adapt to climatic changes when they do occur. As a result, food security, already highly vulnerable across large parts of the continent, will become even more insecure as temperatures rise. Biodiversity May Suffer The human population of Africa isn’t the only one vulnerable to temperature increases. Africa contains around one fifth of the world’s plant, animal and bird species. Many animals are under threat as their traditional habitats are likely to become eroded under the impact of climate change. Concentrations of plant biodiversity, such as the Cape Floral Kingdom, are also threatened by changes in rainfall, and both plants and animals will need migratory ‘corridors’ to allow them to escape should localised habitats become too degraded. Unfortunately, not nearly enough research has been undertaken on the impact of climate change for the human, animal or plant populations of Africa. At the same time, capacity to manage and extend conservation schemes, or to utilize alternative technologies capable of mitigating or harnessing climatic changes, remain underdeveloped. The impact of global warming will therefore have further effects, as massive exploitation of landscapes is likely to occur as conditions across the continent deteriorate. The amount of carbon dioxide now in the atmosphere as a result of a century or more of industrialization means that global warming will continue through the twenty first century, even if all CO2 emissions ceased overnight. But the future for the world’s most precious and vulnerable habitats critically depends on how far, and how quickly, we are able to curb further increases in CO2 emissions. If we continue to consume fossil fuels at our current rate, the future for the people, the animals, and indeed for the planet itself looks bleak. If we act decisively, the ecological fabric of the planet will have a chance to adapt and survive. As African ecologist, Paul Desanker says, “Substantial reductions of heat-trapping gas emissions in developed countries and adaptation strategies are crucial… The conservation of African biodiversity will ensure delivery of ecosystem goods and services necessary to human life support systems (soil health, water, air, etc…). An integrated approach to environmental management is needed to ensure sustainable benefits for Africa.” Exactly the same is true of the Arctic, and indeed of the whole world. Life on earth itself may depend on whether we have wisdom to understand and respond effectively to this challenge. - (1) Snow, Where’d You Go? The Associated Press, 13 January 2005(2) Arctic Climate Impact Assessment (ACIA) - (3) Arctic warming at twice global rate, New Scientist, 02 November 2004 - (4) Ibid - (5) Impacts of a Warming Arctic, ACIA, 2004: 16 - (6) F Pearce, Doomsday Scenario, New Scientist, 22 November 2003 - (7) Ibid - (8) P Desanker, 2002, The Impact of Climate Change on Life in Africa, World Wildlife Fund - (9) Climate Change and Agriculture in Africa - (10) P Desanker, 2002, The Impact of Climate Change on Life in Africa, World Wildlife Fund
In the 17th century, English, Irish and Scots more or less dominated the landscape, with a small number of African slaves. Although there were major economic differences, there were similarities as well. Women were considered second class citizens with little status and few rights. Wheat was grown in abundance, with flour milling being the number one industry and flour being the number one export, making up almost three quarters of all exports from the middle colonies Roark Eventually, the mortality rate in the colonies began to decrease and most indentured servants survived long enough to be free. Some similarities would be the slaves and the status of women in the society. The southern colonies were established early on after the settlement of Jamestown in As a result, the South used many more slaves than New England did. The middle colonies were ruled largely by the British monarchy until William Penn was granted land by the throne and formed Pennsylvania. The North was more town-centered while the South had based the structure of their lives around the plantations. Initially these crops were harvested by indentured servants, but with the growth of plantations, planters started to import slaves from Africa. These land owners were the wealthiest and had control over the laws. The people who lived in the South were most likely farmers. The North and South also had legislatures that had the power to create, amend, and ratify the laws. These men were responsible for judicial and administrative matters in their area. Besides the issue of who ruled in the society, the colonies had many similarities between the two sides. There were similarities for the English colonies. Interestingly, the indentured servants quickly earned their freedom, and began small businesses of their own, helping to shape the complexion of the Northern colonies as an ambitious and industrial economy. He also appointed a governor who had the power to veto any laws passed by the council. The pecking order of society stayed the same with planters and aristocrats followed by merchants, lawyers, doctors, professionals, then a huge number of small farmers, indentured servants following them, and slaves at the bottom. Most were farmers with small plots of land that were maintained by family members and possibly a couple servants. Another advantage to the slave owner was that all children born of slaves also became slaves Roark Both lands had royal governors who controlled and ruled. Although the Northern colonies also had many farms, these were relatively few in number and never competed with the Southern markets such as tobacco. The climate and geography dictated the lives of the New England settlers. The Northern landowners were less advanced on the big-city type deals. Those who lived in New England were more likely to run businesses, fish, manufacture things, and build ships. In the middle colonies there was much diversity in how the people lived, from the religion they practices to the food they ate to how they made their living. This caused a class system to develop that polarized the social structure of the south Roark Although the Northern and Southern colonies in the 17th and 18th centuries shared some similarities, they were, in fact, separate and distinct civilizations. The colonies varied drastically in their economies, treatment of the native people, and their stability, mainly because their reasons for settling in the New World were different as well. Aug 29, · During the seventeenth and eighteenth centuries, the Northern and Southern sections of the American colonies developed distinct societal differences in terms of political involvement and sidedness, economic output, and use of slave labor. Get an answer for 'What are the similarities and differences in social structure and culture between 17th and 18th century American civilization?' and. Colonial Life Compare/Contrast. Author: Susan Godfrey. School: Farmwell Station Middle School students will write a letter from a colonist in one region to a colonist in another region stating the similarities and differences between the two places. Historical Background The southern colonies were established early on after the. The Northern and Southern colonies in the seventeenth century had many differences and similarities in the way their region if the world was maintained and controlled. Those comparisons and contrasts can be discovered through three main aspects: political, social, and economical/5(4). In searching for early causes for the American Civil War, many historians point to the dramatic differences between the Northern and Southern colonies in the late 17th and 18th centuries. During this period, each region developed a distinctive identity that would dramatically affect the manner with.Download
55 trillion kilograms: that's how much carbon could be released into the atmosphere from the soil by mid-century if climate change isn't stopped. And all in the form of greenhouse gases such as CO2 and methane. Tom Crowther (NIOO-KNAW) and his team are publishing the results of a worldwide study into the effects of climate change on the soil in the issue of Nature that comes out on 1 December. For decades, scientists have speculated that rising global temperatures might affect the huge amount of carbon stored in the soil. Carbon is one of the building blocks of life, and nowhere on land are larger carbon stocks to be found than in the soil. Thousands of studies worldwide have produced mixed signals on whether the soil's storage capacity will decrease as the planet warms, or perhaps even increase. A new, worldwide study led by researcher Tom Crowther (Netherlands Institute of Ecology NIOO-KNAW, formerly of Yale University) finally answers that question: "The effect will be roughly equivalent to adding another industrialized country to the planet, the size of the United States." "If climate change isn't stopped, an additional 55 trillion kilograms of carbon will be released into the atmosphere by the year 2050", says Crowther. It will be released in the form of CO2 or methane: greenhouse gases, speeding up what would otherwise have been a natural process. "It's about 17 percent more than the projected emissions due to human-related activities during that period", says Crowther. And those greenhouse gases could further accelerate global warming, which would have even more of an impact on the soil: a full-fledged domino effect. So why was this not obvious all along? Because researchers were looking in the wrong places, argues Crowther. "With data from more than 40 institutes around the world, covering 20 years, our scope is now finally worldwide." Despite his young age, the lead author has built-up an impressive amount of experience working with such big data. This year, he's already published comparable studies in Science, PNAS and Nature Climate Change. Coming in from the cold One area that is conspicuous by its absence from most earlier studies is the (sub)arctic. "Yet at high latitudes is where the largest carbon stocks are, and where the impact of climate change will be the greatest." The release of those stocks - built up over thousands of years - will be accelerated by climate change because it stimulates soil life. Micro-organisms in the soil, in particular, will become more active. Factors that could slow down this process, or speed it up even further, should also be considered. With more CO2 in the atmosphere, for instance, plant growth will also be accelerated. That's why the international researchers have reserved a margin for the extra emissions: between 12% and 17%. But whatever the exact amount will turn out to be, one thing is clear, believes Crowther: it's going to be substantial. "Now that this longstanding scientific query has been answered at last, we should adjust international climate models accordingly, and do this as quickly as possible. The same goes for policy."
Cyclists have the same rights and responsibilities as drivers and motorcycle riders. When riding a bicycle, you should: - Correctly wear an approved helmet, with straps fitting snug under the chin - Obey all the road rules. - Ride, like all traffic, on the left hand side of the road unless otherwise signposted. - Only ride on a footpath if aged under 12 years (or an adult accompanying a rider under 12 years). - Use a bicycle lane if one is marked on the road, unless impractical to do so. - Always use hand signals when turning or stopping. - Walk, not ride, across pedestrian crossings. - Travel no more than 1.5 meters apart from each other if riding two abreast. - Slow down on a cycle path when pedestrians are present. - Warn pedestrians of your approach on a cycle path. All bicycles must: - Be fitted with an effective brake and bell, horn or similar warning device. - If used at night have a steady or flashing white light on the front. - If used at night have a red reflector and steady or flashing red light at the rear. Keep your bike healthy Always carry a pump, tyre levers, spare tube patch kit and water bottle. Check your tyre pressure, quick release skewers, brakes and loose bearings regularly. Maintenance is important. If you do not feel confident working on your bike, take it to a good cycle shop for servicing. Clean the drive chain on your cycle regularly and then apply an appropriate lubricant according to the instructions. Wipe off the excess, less is more! (Excess lube attracts dirt). Replacing your tube after a flat tyre: - Loosen quick release lever or axle nuts as appropriate. - Remove wheel from the bike frame. - Remove one tyre bead from the rim - use tyre levers if necessary. - Extract the tube from under the tyre. - Try to identify what caused the flat - find the hole and search for sharp items still within the tyre. - Repair the tube with a tyre patch, or use a new tube. - Slightly inflate the tube and place inside the tyre. - Place valve through hole in rim. - Patiently work the bead back onto the rim gradually moving around. Deflate the tube if necessary. Avoid using tyre levers if possible. - Partially inflate. Check tyre is seated in the rim and valve is straight. Deflate and reseat the tyre if necessary. - Inflate to full pressure and fit wheel to bike. Buy a good quality "U-Lock" or cable lock (with cable of at least 8mm thick) from a cycle store. You can secure your frame and rear wheel just by locking the wheel within the rear triangle to something secure. If you do the same trip regularly then consider leaving a lock at your destination to avoid carrying a heavy lock every time.
The goal of the Social Studies department at HSCL is to cultivate strong members of the community who know the geography and history of the world, the history of our country, and the functions of government. To that end, students are provided with rich content that allows them to insightfully consider big ideas in history, geography, economics, civics, citizenship, and government through curricula integrated with Common Core literacy standards. Students learn about the world through inquiry-based instruction, which allows students to understand, interpret, and gain insight into important events in the world. By exploring disciplines such as anthropology, archaeology, economics, geography, history, law, philosophy, political science, psychology, religion, and sociology, students gain insight into the world in which they live in order to become civically engaged members of society. U.S. History & Government Freshman Social Studies introduces students to the content of United States history and government from its foundation to the present day, as well as important literacy skills in reading and writing about history. Students learn to determine central ideas within a variety of texts as well as to read history from different perspectives. Traditional and nontraditional historical perspectives, such as those presented in Howard Zinn’s A People’s History of the United States, are analyzed. During this course students are also introduced to the skills necessary for the construction of arguments supported by textual evidence from primary sources, such as the Declaration of Independence, and secondary sources, including important pieces of historical literature such as Upton Sinclair’s The Jungle. Some of the major themes covered during this course are nation-building, the Constitution and constitutional flexibility, global power and foreign policy, the role of government in economic and social life, and social and political reform movements. Upon completion of this course, students sit for the New York State Regents in United States History and Government. Global History I – Ancient and Classical Civilizations Sophomore Social Studies deepens students’ literacy skills developed during freshman year while emphasizing historical research. Students in this two-course sequence of Global History begin to produce research projects that require the collection, interpretation, and integration of a variety of source materials. Students also learn to use online archives of academic journals like JSTOR to carry out research and to employ MLA formatting for research papers and citation. Some of the major themes covered during sophomore year include the impact of geography on early societies, the rise and fall of empires, as well as the lasting impact of the past on the present. Global History during 10th grade aligns to the Global Literature class, in which students read a variety of texts from the ancient world through the European Renaissance. Global History II- From the Enlightenment to Global Interdependence and the Contemporary Era Students continue their study of Global History during junior year with a two-part sequence: 1) Revolutions: Political, Social, Economic, and Technological and 2) From Anti-colonial Movements to the Age of Globalization. Through an integrated approach to developing students’ writing and reading processes, this course will develop and maintain skills needed to succeed in high school and beyond. This course includes developing writing, thinking, and study skills in order to develop an understanding of global connections made across time and place, from the past to the present. This course allows students to understand and enjoy history. Upon completion of this course, students sit for the New York State Regents in Global History and Geography.
Marie Laure Ryan Experiment Difficulty of Project The cost of Xeroxing Approximate Time Required to Complete the Project About an hour. - To identify how readers choose possible worlds from a text. - To categorize different types of possible worlds and how they are linked to different kinds of readers. Materials and Equipment / Ingredients - A short story - Approval to experiment on humans Reading is not merely a process of understanding what occurred in a plot—it is also a process of prediction. As a person reads, a part of his/her brain is always wondering what will happen next. Marie Laure Ryan, a literary theorist, theorizes that every time a reader encounters an important plot point, he/she uses this information to predict an entire plotline. For example, if you are reading about a woman who gets her purse stolen, you might think, “I bet she tracks down that thug and beats him senseless.” However, if the reader discovers new information in the story that contradicts the plotline they’ve predicted, the reader changes the plotline to match the new information. For example, when reading about the woman whose purse is stolen, you discover that the purse thief is a homicidal maniac. That means that the woman is far less likely to track him down. Now you predict that the thief will track down the woman, and try to finish her off. Empirical evidence has shown that some readers do use this process while reading. However, it is not clear which readers use this process and how they use it. What kinds of readers create possible storylines while reading? How does one categorize the different worlds that readers come up with? - What characterizes a reader who creates possible worlds while reading? - What categories of possible worlds do readers create? Terms, Concepts and Questions to Start Background Research - What is Narratology? - What are Possible Worlds? How do they work? - How would you characterize the ways in which different people read? - What are important demographic factors that might contribute to the result of this experiment? - Identify a story that would be appropriate for this experiment, and which is obscure enough that you believe no one taking part in this experiment has read it before. - Apply for approval, from your teacher or a committee, to test on humans. - Create a general demographic survey questionnaire that the readers can answer first, so that you can later analyze how these factors affect their predictions. - Break the story into different subsections based on key actions or information that is presented. - Create questionnaires that readers will answer after they have finished reading a section of the story. These questionnaires will contain questions that lead the readers to write down their theories for what will happen next. - Gather a group of volunteers together and give them the story. Make sure they give the story back to you before you give them the questionnaires. Once you are done, analyze your results. Ryan, Marie Laure. “From Parallel Universes to Possible Worlds: Ontological Pluralism in Physics, Narratology, and Narrative”. Poetics Today 27:4 (Winter 2006). Ryan, Marie Laure. Possible Worlds, Artificial Intelligence, and Narrative Theory. Indiana University Press. Indianapolis: 1991. Ronen, Ruth. “Paradigm Shifts in Plot Models: An Outline of the History of Narratology.” Poetics Today 11:4 (Winter 1990). Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.
Water Around a Fresh Crater These images show a very young lunar crater on the side of the moon that faces away from Earth, as viewed by NASA's Moon Mineralogy Mapper on the Indian Space Research Organization's Chandrayaan-1 spacecraft. On the left is an image showing brightness at shorter infrared wavelengths. On the right, the distribution of water-rich minerals (light blue) is shown around a small crater. Both water- and hydroxyl-rich materials were found to be associated with material ejected from the crater. Credits: ISRO/NASA/JPL-Caltech/USGS/Brown Univ. › Full resolution jpeg (106 Kb)
Staying safe online KEEPING YOUR CHILDREN SAFE Millions of young children use the Internet daily. Parents need to know about the dangers the Internet poses to children. Studies show that: - one out of every 17 children feel threatened or harassed online - one out of every five children receive sexual solicitation online, and - one in four children see unwanted sexual material. Children don't always tell their parents when these incidents happen, so parents should track how their children use the Internet. Follow these tips to protect your children when they're online: - Keep your computer in a common area like the living room. It’s easier to keep an eye on your children. - Check the history button on your Internet browser to see which websites your children are visiting. - Check for open applications along the bottom of your computer screen. There may be hidden ones that your children don’t want you to see. - Never allow your child to send pictures without your permission. - Tell your child not to open an email unless it's from someone they know. - Enable parental controls on your computer and browser. - Teach your children to never give out personal information, including names and addresses, phone numbers, school names, and any information that can identify them. WHAT ELSE CAN YOU DO? Make sure your child tells you right away if they see something that makes them uncomfortable. Report these situations to your Internet Service Provider or the police if necessary. Your child also needs to know that things they say or do online can hurt other people, too. They should be careful about what they post. Some children have even been charged for committing crimes online.
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Next year will mark the tenth anniversary of the first draft of the human genome. It has provided tremendous insight into human genes, and formidable advances in biotechnology have accompanied this genomic breakthrough. However, the way these genes and their products interact with one another still has to be fully understood. Maths plays a central role in this understanding, partly because new biotechnologies produce vast amounts of data that have to be coped with somehow. But it's not just about quantity — mathematical models of genetic processes can provide qualitative insight into how things work. In our work at University College London a pretty straightforward model has helped to understand molecular processes that are relevant to cancer biology. What does DNA do? What causes a healthy cell to become cancerous? DNA is important to the functioning of cells because it acts as a template for proteins, which are among the active molecular agents in cells. Turning the information coded in the DNA into proteins is not a straightforward process. There is an intermediary molecule, aptly named messenger RNA (mRNA), which is produced by a molecular apparatus called RNA polymerase. RNA polymerase reads the information on the DNA and produces mRNA molecules as it slides along the DNA. This first step is termed transcription and the mRNA molecule is called a transcript. A gene is a part of DNA that codes for a specific protein. The second step is called translation. Here the mRNA molecule is treated by another molecular machine, the ribosome. It reads the mRNA to produce chains of amino acids, which when folded become active proteins. A single molecule of mRNA can be used several times to produce more than one protein. Only a portion of the DNA codes for proteins and in certain organisms that portion is actually quite small. For example, in us humans, only 2% of the DNA codes for proteins. Another twist is that in an individual cell not all coding portions of the DNA are used. This is because individual cells in multicellular organisms typically perform specialised functions — a liver cell is different from a skin cell — so they don't need the entire coding repertoire contained in the DNA. In the same vein, not all proteins are being continuously produced, as some of them are needed on specific occasions only. How is DNA switched on? So, what causes a particular gene to be turned on — or expressed in biological jargon — in an individual cell? There are many factors that can influence gene expression, but a major role is played by special molecules called transcription factors. These attach to regulatory regions of the DNA and recruit the transcription machinery to express the adjacent gene. Transcription factors can also act as repressors, ie diminish the expression of certain genes. They can work in combination with other transcription factors, or bind to other non-coding sequences of the DNA. If this wasn't complicated enough, transcription factors are proteins themselves, so they may arise from the work of other transcription factors or cause their appearance. These chains of transcription factors can branch back onto themselves, creating feedback loops. In summary, life at the molecular level is rather baroque and understanding how complex networks of genes and proteins are connected and function is one of the major challenges of contemporary biology. A transcription factor (blue) binding to DNA (red). One system that's particularly interesting, and linked to the formation of cancer, is the DNA damage response network. When a cell's DNA has been damaged repair mechanisms systematically spring into action. But these mechanisms don't always get things right. They can commit errors, which can lead to cancerous mutations threatening the whole organism. To try and avoid such danger, a cell affected by a potentially dangerous mutation has the option to commit suicide — called apoptosis — for the greater good. One transcription factor that's heavily involved in directing these voluntary cell deaths is called p53. It has been found to be mutated in about half of human cancers. So if we can understand exactly which genes p53 helps to express, then this could help to find ways to fight the disease. Finding target genes Identifying the target genes of p53 involved some mathematical detective work. The extent to which a given gene is being expressed in a particular cell can be measured by looking at the concentration of mRNA in the cell — the more mRNA there is, the more the gene is being expressed. If p53 is implicated in the expression of the gene, then a high concentration of mRNA should coincide with high activity of p53, and a low concentration with low activity. We can make this intuition precise using a differential equation (if you haven't come across a differential equation before, look at the box on the right): Here the function describes how much of mRNA there is at time The left hand side of the equation is the derivative of with respect to time: it describes the rate at which the quantity changes over time. According to this equation, the rate of change of the mRNA quantity is the sum of three terms. The first () corresponds to a constant - or basal - rate of mRNA production (the bathtub equivalent is an open tap no one fiddles with). Each gene comes with its own constant . The second term is more interesting, as it can vary over time. It’s a product of two things. The first is the component which describes the transcription factor activity. It’s a sort of profile of how p53 behaves, which is independent of the particular gene we’re looking at. The second factor is a constant . This constant is specific to the gene, and describes to what extent p53 is involved in mRNA production. For some genes, this constant will be close to zero, indicating that the transcription factor has little or no influence whatsoever on that particular transcript’s production. We are of course interested in those genes that are sensitive to the transcription factor activity, namely those that have a sensitivity constant that is significantly greater than zero. The third and last term () describes the loss (or degradation) of mRNA, hence the negative sign attached to it. This corresponds to "leaking" mRNA molecules. (Actually, leaking is not quite the right word: the mRNA molecules may be chopped up before having a chance of being translated into proteins, rather than literally leaking out of the cells. But in any case, they disappear.) The rate of loss of mRNA is not constant, but proportional to the quantity of molecules that are present there and then (in contrast to the bath tub analogy). This is because more molecules are likely to be degraded if more are present in the cells. That’s why the constant is multiplied by Finding target genes of p53 is a reverse bathtub problem. This model now gives us a strategy for finding out whether p53 is involved in the expression of a given gene. Using microarrays we can measure the quantity of mRNA over time, and the rate at which this is changing. We can then try and find constants and which make the equation work. The dependency status of individual genes to p53 is captured by the sensitivity to the transcription factor activity, which is described by the parameter in the model. To be a potential target, the sensitivity has to be quite large, and the model has to fit the data well enough. (Note that this situation is different from our bathtub example. With the bathtub, we knew all the constants that made up the equation, and were after the function which described the state of the system at time In this case we know the state of the system, given by and are after the constants that make up the equation. In some sense, this is an inverse problem, and this kind of endeavour is indeed often called reverse engineering.) The missing link So far, so good, but it turns out that we’re actually missing a crucial bit of information – the transcription factor profile described by the function Trying to deduce as well as and from the data at hand would involve creating more information than there was to start with, the mathematical equivalent of creating perpetual motion. But thankfully, p53 is an important transcription factor and fairly well-documented. Some of its target genes are already known. Using this information and fitting a handful of the known target genes to our model, we were able to deduce the activity profile of p53. That activity profile was then used to fish out potential targets of p53: these were genes whose expression profiles fitted the model well, and had a high sensitivity constant Our predictions were later confirmed by an independent experiment – the genes we identified really were targets of p53. The icing on the cake was that a significant proportion of those confirmed predictions were of genes that weren’t previously known to be p53 targets. Knowing targets of a single transcription factor is admittedly only a portion of the bigger picture sketched above. For example, p53 is only one among several transcription factors that is being activated upon DNA damage. By rearranging our model for gene expression and combining it with transcript turnover rates, we have been able to extract the main transcriptional activities governing the cellular response to stress. We are now working on trying to understand how these activities combine in stressed cells. In summary, a lot remains to be done to fully understand this system (and others) but there is little doubt mathematics will play a central role in this process. About the authors Martino Barenco is a mathematician at the Institute of Child Health. After working for seven years as an economist in Switzerland, he came to London to study chaos theory. He is still in Britain because he likes the local sense of humour and the weather. Mike Hubank is a Senior Lecturer at The Institute of Child Health, University College London.
#Evidence was found in a rare mineral that records global temperatures #Warming was global and NOT limited to Europe #Throws doubt on orthodoxies around 'global warming' Current theories of the causes and impact of global warming have been thrown into question by a new study which shows that during medieval times the whole of the planet heated up. It then cooled down naturally and there was even a 'mini ice age'. A team of scientists led by geochemist Zunli Lu from Syracuse University in New York state, has found that contrary to the ‘consensus’, the ‘Medieval Warm Period’ approximately 500 to 1,000 years ago wasn’t just confined to Europe. In fact, it extended all the way down to Antarctica – which means that the Earth has already experience global warming without the aid of human CO2 emissions. Article continues below this advert: At present the Intergovernmental Panel on Climate Change (IPCC) argues that the Medieval Warm Period was confined to Europe – therefore that the warming we’re experiencing now is a man-made phenomenon. However, Professor Lu has shown that this isn’t true – and the evidence lies with a rare mineral called ikaite, which forms in cold waters. ‘Ikaite is an icy version of limestone,’ said Lu. ‘The crystals are only stable under cold conditions and actually melt at room temperature.’ It turns out the water that holds the crystal structure together - called the hydration water - traps information about temperatures present when the crystals formed. This finding by Lu's research team establishes, for the first time, ikaite as a reliable way to study past climate conditions The scientists studied ikaite crystals from sediment cores drilled off the coast of Antarctica. The sediment layers were deposited over 2,000 years. The scientists were particularly interested in crystals found in layers deposited during the ‘Little Ice Age,’ approximately 300 to 500 years ago, and during the Medieval Warm Period before it. Both climate events have been documented in Northern Europe, but studies have been inconclusive as to whether the conditions in Northern Europe extended to Antarctica. Lu’s team found that in fact, they did. They were able to deduce this by studying the amount of heavy oxygen isotopes found in the crystals. During cool periods there are lots, during warm periods there aren’t. ‘We showed that the Northern European climate events influenced climate conditions in Antarctica,’ Lu says. ‘More importantly, we are extremely happy to figure out how to get a climate signal out of this peculiar mineral. A new proxy is always welcome when studying past climate changes.’ The research was recently published online in the journal Earth And Planetary Science Letters and will appear in print on April 1. Click source for more
Slovakia’s Landscape, climate and water flow While a major part of the Slovak territory is located in the Carpathian Mountains, almost one quarter of the country is formed by lowlands. The Vienna Basin extends into Slovakia from the west, the Pannonian Plain from the southwest and the Great Danubian Basin from the southeast. These lowlands form part of the ecological region known as the Hungarian lowlands. The climate of Slovakia is influenced by its location in a temperate zone. There are several types of climate regions within the country – from cold mountain (along the upper Váh River) to warm dry regions with moderate winters and more sunlight in the south. Streams rising in Slovakia have relatively unstable discharges. High discharges occur periodically in spring months from March to April; with low discharges in summer and autumn. Slovakia’s borders overlap several hydrologic areas, giving rise to problems of assessing water flow in and out of the country. Several rivers with high water-bearing capacity have an eccentric influence on the country, especially the Danube River flowing from Austria, the Tisza River flowing from Ukraine and the Morava River flowing from the Czech Republic. The average discharge of Slovak Rivers is 3,328 m³.s-1, of which only 398 m³.s-1 (12 %) rise in the country. Hydropower plants provide almost 30% of the present energy production in the Slovak Republic. Natural highlights include: The Danube Floodplains – from Bratislava to Klizská; the Morava Floodplains – a well-developed complex of diverse wetlands; the Latorica Floodplain area – housing many threatened and rare aquatic and swamp species; and a 6 km stretch of the Tisza River – shared with Hungary and Ukraine and containing rare examples of natural and near-natural wetland types. Some 2,825 settlements are situated in the Slovak share of the Danube River Basin District with over 5 million inhabitants. In urban areas, most of the larger rivers are modified for flood protection. On larger rivers with catchments above 1,000km², the most radical regulations are seen on the Uh and Latorica Rivers and on the Morava, which is 100% regulated. The hydropower potential of several rivers is used for energy production, including the Danube, Váh, Hornád and the Ondava. Half of the land in the Danube River Basin District of the Slovak Republic is used for agriculture. Rivers in the Slovak Republic receive insufficiently treated wastewater from agglomerations, industry and agriculture. Smaller waters are often influenced by diffuse pollution from households in settlements which are not connected to public sewage systems. In 2005, only 57.1% of the population was connected to sewage systems. Of the 1659 surface water bodies identified in the Slovak part of the Danube River Basin District, 817 were classified as ‘at risk’ of failing to reach ‘good ecological status’ by the year 2015, 505 were classified as ‘possibly at risk’ and 343 were ‘not at risk’. Of the 96 groundwater bodies identified in the Slovak part of the Danube River Basin District, 7 are considered ‘at risk’ of failing to reach ‘good chemical status’ due to point source pollution and 16 due to diffuse pollution. All 23 water bodies identified as lakes are heavily modified water bodies. Due to groundwater abstractions, nine groundwater bodies are ‘at risk’ of failing to reach ‘good quantitative status’ For detailed information on the above, download the fact sheet below. The information contained in the ICPDR website is intended to enhance public access to information about the ICPDR and the Danube River. The information is correct to the best of the knowledge of the ICPDR Secretariat. If errors are brought to our attention we will try to correct them. The ICPDR, expert group members, nor other parties involved in preparation of information contained on this website cannot, however, be held responsible for the correctness and validity of the data and information provided, nor accept responsibility or liability for damages or losses arising directly or indirectly from the use of the information conveyed therein. Only those documents clearly marked ICPDR documents reflect the position of the ICPDR. Any links to other websites are provided for your convenience only. The ICPDR does not accept any responsibility for the accuracy, availability, or appropriateness to the user's purposes, of any information or services on any other website. When using the information and material provided on this website, credit should be given to the ICPDR.
Febrile (fever) seizures are terrifying for parents to witness; however they are usually not serious and do not cause brain damage. Approximately 2 to 5 percent of children have one febrile seizure between the ages of 6 months and 5 years old; of those, one-third will have a second seizure, and about one half of those will have a third. According to the National Institute of Neurological Disorders and Stroke, children rarely develop their first febrile seizure before the age of 6 months or after 3 years of age. The older a child is when the first febrile seizure occurs, the less likely that child is to have another. The precise cause of febrile seizures is not known; however, they are associated with high fevers (over 102 degrees F) and they appear to be related to the rate of rise in temperature more than the actual temperature of the fever. In other words, a child who rapidly develops a fever of 103 degrees seems to be at greater risk of having a seizure than a child who slowly develops a fever of 104 degrees F. Febrile seizures also tend to run in families, causing doctors to believe they may be genetically related. Many parents worry that if their child has a febrile seizure, he or she will develop epilepsy later in life. However, according to the National Institute of Neurological Disorders and Stroke, only 2 to 5 percent of children who have febrile seizures go on to develop epilepsy. Most febrile seizures happen in the first few hours of a child's fever. During a seizure, his eyes may roll back in his head, his body may twitch or jerk, his limbs may stiffen, and he may drool and vomit. The seizure may last only a few seconds or up to several minutes. However, if the seizure lasts for more than 10 minutes or if your child starts choking, stops breathing, or turns blue, call 911 immediately. If your baby is having a seizure, place him on a protected surface, such as the floor, away from any sharp objects. Lay him on his side or stomach to prevent choking if he does vomit. As hard as it may be to watch, don't try to hold or restrain your child during the seizure and never place anything in a seizing child's mouth as he could choke on it. After the seizure has subsided he may seem a bit sleepy, but many children return to normal activity immediately. If your child has a seizure, he should be examined by a doctor to ensure the seizure was caused by the fever and not by another condition (such as meningitis or severe dehydration). You should seek immediate medical attention if he has a stiff neck, is extremely lethargic, or continues to vomit. Doctors will test on your child's blood and urine and may perform a spinal tap to determine the cause of the seizure. A child who has a febrile seizure usually doesn't need to be hospitalized; however, if the seizure is prolonged or is accompanied by a serious infection, or if the source of the infection cannot be determined, the doctor may recommend that the child be hospitalized for observation. Oral anticonvulsant medications have been proven to reduce the risk of a recurrent febrile seizure when given during illness (Phenobarbital and valproate); however, the side effects of these medications may be significant and many pediatricians are hesitant to prescribe them. Giving a fever reducer, such as Tylenol or Motrin, at the first sign of a fever is often recommended, but has not been proven to prevent a febrile seizure. The only real way to prevent febrile seizures is to avoid colds and the flu that can cause fever, which is no easy task with young children. However, the American Academy of Pediatrics now recommends infants older than 6 months receive a flu shot every autumn, which will help prevent illness.
In these lessons, we will learn the sine function or sine ratio, how to use the SOH formula, how the sine ratio was discovered and how to solve some word problems using the sine function. Related Topics: More Lessons on Trigonometry The three common trigonometry functions are tangent, sine and cosine. You may use want to use some mnemonics to help you remember the trigonometric functions. One common mnemonic is to remember the SOH-CAH-TOA. In this lesson, we will consider the sine function. The sine of an angle is the ratio of the opposite side to the hypotenuse side. Sine is usually abbreviated as sin. Sine θ can be written as sin θ Calculate the value of sin θ in the following triangle. The following video shows examples of using the sine function. Using the Sine Formula (the SOH formula) - part 1. Using the Sine Formula (the SOH formula) - part 2. Discovery of Sine Function The discovery and use of the sine function. The Sine Ratio An intro to the right triangle definitions of sine Sine Function Word Problems A word problem involving the trigonometric ratio of sine to calculate the height of a pole A 55ft wire connects a point on the groud to the top of a pole. The cable makes an angle of 60 degrees to the ground. Find the height of the pole to the nearest foot. Multiple-Step SOH CAH TOA Problems Two ladders are leaning against a building as shown. What is the angle below the shorter angle? Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget, a free math problem solver that answers your questions with step-by-step explanations. You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations. We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.
A sandbox is a container on most locomotives, multiple units and trams that holds sand, which is dropped on the rail in front of the driving wheels in wet and slippery conditions and on steep grades in order to improve traction. The sand may be delivered by gravity, by a steam-blast (steam locomotives) or by compressed air. Gravity sanding requires that the sand be dry so that it runs freely. Locomotives used multiple sandboxes, so that their delivery pipes could be short and near-vertical. Engine sheds in the UK were equipped with sand drying stoves, so that sandboxes could be refilled each morning with dry sand. Steam locomotives in the USA had a single sandbox, called a sand dome on top of the boiler where the rising heat helped to dry the sand. Even with this arrangement, sand pipes tended to clog, and by the 1880s, pneumatic sanding systems were being proposed. The development of steam sanding was influential on locomotive design. As the sand could now be blown horizontally and directly under the wheels, it was no longer blown away by cross-winds before it could be effective. This prompted a resurgence of interest in some older single-driver locomotive designs, that had previously been limited by their adhesion performance. The development of Holt's steam sanding gear on the Midland Railway in 1886 prompted Johnson to design his successful 'Spinners' of 1887, twenty-one years after the last singles, and which would remain in production for a further sixteen years. Diesel and electric locomotives On diesel and electric locomotives and railcars, sandboxes were and are fitted close to the wheels so as to achieve the shortest possible length of delivery pipe. Depots may have a sand drier installed to warm and to dry the sand before it is used. \|Wikimedia Commons has media related to Sandboxes (locomotive).\| \|This rail-transport related article is a stub. You can help Wikipedia by expanding it.\|
The importance of Macaronesia as a source of hidden genetic diversity is so strong that it has triggered several studies in the past years, which settled the basis for our current knowledge about biogeographical patterns in the region. However, sources floras and the available of dispersal vectors have changed dramatically. This precludes conclusions of whether the current flora is a relic of a wider past distribution or a result of long-distance dispersal events between isolated areas. Bryophytes, the earliest group of land plants, constitute the best system to shed light about this question since they can persist in microhabitats, long after the general climate of the region has changed. Phylogenetic and population genetic analysis of Macaronesian early land plants provide evidence of cryptic speciation, connectivity among and between archipelagos and, multiple independent events of colonization from different continents [Sim-Sim2014] [Stech2008] [Vanderpoorten2008]. Yet, biogeographic studies on the Macaronesian early land plants have been mainly descriptive or focused in reconstructing patterns in one single The main objective of MacPhylo is to unravel the origin and diversification of the Macaronesian flora, using bryophytes as a model, with an integrative approach that combines new phylogenomic methods, geological information, biogeographic dating and niche models. For the first time, a meta-analysis will be conducted using different genus of early plants to solve the following questions: 1. Did the Macaronesian region act as glacial refugia, from which other areas where subsequently re-colonized or do patterns conform to a scenario of high divergence and isolation? 2. Can the patterns of Macaronesian flora be better explained by long-distance dispersal events or as a result of an ancient vicariance scenario? 3. Has gene flow occurred between the different islands of the Macaronesia archipelagos involving the typical scenario of colonization from the older to the newest islands or did dispersal erase any phylogeographical signal? 4. Does species exhibit different colonization routes to the Macaronesia and is it related with specific requirements (eg. does narrow endemics show single colonization events whereas widespread species show multiple ones)? Understand the biodiversity (habitats and species) of this region and its relationship with environmental variables, will improve the awareness among the scientific community about strategies used by researchers to deal with actual problems, such as, climate changes, invasions of exotic species, diseases, coverage and frequency species changes among other threats to actual and future generations. Science and Technology Foundation Universidade da Madeira, Funchal, Madeira Netherlands Centre for Biodiversity (NCB Naturalis), Leiden, The Netherlands Universidade de Brasília, Brasil Universidade de La Laguna, Tenerife, Canárias Universidade de British Columbia, Vancouver, Canada. Universidade Técnica Particular de Loja, Loja, Equador
A team of researchers say that in spite of all the media attention given to the Arctic region and polar bears, species living in the tropics may face an even greater risk as the world warms up. Shrinking polar ice has concerned ecologists that polar bears will soon start dying off as their hunting ground literally melts away. However, according to a team led by University of Washington, while temperature changes will be much more extreme at high latitudes, tropical species have a far greater risk of extinction since even relatively slight warming of just a degree or two can have a devastating impact. The Daily Galaxy asked Joshua Tewksbury, a biologist at the University of Washington who is studying tropic species, why these warm weather species are in greater danger. After all, it’s already warm where they live, so how could just a degree or two of warming make much of a difference? “We’re looking specifically at the intersection between where an organism lives, and how susceptible they are to change. What we found is that organisms in the tropics are much less resilient to heat change,” Tewksbury explained to The Daily Galaxy. Why? Because tropic species are adapted to living within a much more narrow temperature range. Once temperatures get beyond that comfortable range, many species will likely have a difficult time coping. Geographically, Earth’s tropical region is a giant belt that stretches from the Tropic of Cancer to the Tropic of Capricorn; or, in actual terms, just south of Miami to half way through Australia. However a more scientific definition is taken by meteorologists who define the tropics as a region defined by a long term climate. It is this definition that has shown the shift in the width of the tropics towards our planet’s poles. "There's a strong relationship between your physiology and the climate you live in," said Tewksbury, "In the tropics many species appear to be living at or near their thermal optimum, a temperature that lets them thrive. But once temperature gets above the thermal optimum, fitness levels most likely decline quickly and there may not be much they can do about it." Arctic species, on the other hand, often experience temperatures ranging from subzero to a comparatively warm 60 degrees Fahrenheit. They typically live at temperatures well below their thermal limit, and most will continue to do so even with climate change. "Many tropical species can only tolerate a narrow range of temperatures because the climate they experience is pretty constant throughout the year," said Curtis Deutsch, an assistant professor of atmospheric and oceanic sciences at the University of California, Los Angeles. "Our calculations show that they will be harmed by rising temperatures more than would species in cold climates. "Unfortunately, the tropics also hold the large majority of species on the planet," he said. Tewksbury and Deutsch are lead authors of a paper detailing the research, published in the May 6 print edition of the Proceedings of the National Academy of Sciences. The scientists compared data describing the relationship between temperatures and fitness for a variety of temperate and tropical insect species, as well as frogs, lizards and turtles. Fitness levels were measured by examining population growth rates in combination with physical performance. "The direct effects of climate change on the organisms we studied appear to depend a lot more on the organisms' flexibility than on the amount of warming predicted for where they live," Tewksbury said. "The tropical species in our data were mostly thermal specialists, meaning that their current climate is nearly ideal and any temperature increases will spell trouble for them." So does that mean that we should turn our focus away from the Arctic? Definitely not, says Tewksbury. Polar bears are in danger, but its just for different reasons than for tropic species. It’s not the temperature itself that will harm the bears—they already live in a climate that varies wildly throughout the year—what will harm them is the loss of habitat they will face as polar ice disappears. Many tropic species, on the other hand, will actually likely be harmed directly from the rising temperature itself since their physiology cannot handle the vastly swaying temperatures like the bears can. “The polar bears are in trouble, but what many don’t know is that even a small amount of change in the tropics could effect a vast number of species,” Tewksbury told The Daily Galaxy. “People won’t see as dramatic decline, because many tropic species that will be effected like insects and lizards, simply don’t have the appeal that the polar bear has. Yet they are still vitally important to their ecosystems.” Independent teams set out to measure the atmospheric data available, and using four different meteorological measurements, found that the tropical belt has grown by between 2 and 4.8 degrees of latitude since 1979. This measurement translates to a total expansion – north and south – of 140 to 330 miles. Climate scientists have long predicted that, by the end of the 21st century, a growth of the tropical belt was expected. But the growth that has taken place over the last quarter-century is puzzling, and not part of their theories. Dian Seidel, a research meteorologist with the National Oceanic and Atmospheric Administration lab in Silver Spring, Md, is confused. "They are big changes," she said. "It's a little puzzling." And while one explanation for the expanding tropics is indeed global warming, others vie for ranking as another explanation. Depletions in the ozone layer and changes in El Nino are both other options that could explain what has happened. So while much of the tropics are thought to be just that – tropical – there are great swathes of desert as well. One only needs to look at Australia to see that played out, with the ‘Top End’ dominated by rain forests and rainy seasons, that sit just on top of the massive desert center. It is these desert areas that sit on the edge of tropical locations, such as the U.S. Southwest, parts of the Mediterranean, and of course Australia, that are at the most risk, according to the experts. While warming is happening much faster at higher elevations, it is also occurring at a slower rate in tropic zones, which over time will likely just as severe of an impact, but for different reasons. They may not be as majestic as polar bears, says Tewksbury, but we can’t forget about the little guys. Posted by Rebecca Sato. Related Galaxy posts: The “Little Ice Age” Argument Makes a Comeback: Abrupt Climate Change Goes Both Ways, Warns Scientist Abrupt Climate Change: Inevitable Surprises Cosmic Rays -The Cause of Global Warming? The Milky Way Enigma -How Galactic Forces May Control Life on Earth Are Global Warming Models Accurately Predicting Our Future? New Study Reveals the Answer—A Galaxy Interview
A place where we publish health matters, stories, education and news from all over the world! Get involved with us. We look forward for your engagement on our interactive health platform. See you around Septicemia is bacteria in the blood (bacteremia) that often occurs with severe infections. Septicemia is a serious, life-threatening infection that gets worse very quickly. It can arise from infections throughout the body, including infections in the lungs, abdomen, and urinary tract. It may come before or at the same time as infections of the: · Bone (osteomyelitis) · Central nervous system (meningitis) · Heart (endocarditis) · Other tissues Septicemia can begin with: · High fever · Rapid breathing · Rapid heart rate The person looks very ill. The symptoms quickly progress to: · Confusion or other changes in mental status · Red spots on the skin (petechiae and ecchymosis) There may be decreased or no urine output Septicemia is a serious condition that requires a hospital stay. You may be admitted to an intensive care unit (ICU). You may be given: · Antibiotics to treat the infection · Fluids and medicines by IV to maintain the blood pressure · Plasma or other blood products to correct any clotting problems Getting treated for infections can prevent septicemia. The Haemophilus influenza B (HIB) vaccine and S. pneumonia vaccine have already reduced the number of septicemia cases in children. Both are recommended childhood immunizations. In rare cases, people who are in close contact with someone who has septicemia may be prescribed preventive antibiotics.
What is the Pituitary gland? So your mind is racing and your heart is pounding - so many questions - so much to take in - where to start? Lets start with the basics. The Endocrine System The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as hormones. The endocrine system is instrumental in regulating metabolism, growth, development and puberty, tissue function, and also plays a part in determining mood. The field of medicine that deals with disorders of endocrine glands is endocrinology, a branch of the wider field of internal medicine. Endocrine glands regulate your body chemistry by releasing hormones directly in to the blood system, which stimulate or inhibit activity in the target cells. They are like remote-control devices for your body's many cells and systems. It would be far too complicated to communicate with each cell in the body directly, so instead the brain controls similar types of cells using hormones released in to the blood stream. To give you an example of how this works, imagine your sudden rise in heart rate when danger threatens or an emergency situation arises - this is caused by another 'remote control' hormone: adrenaline. This hormone, released by the adrenal gland on top of your kidney, has a very immediate and noticeable effect on your body. The hormones released from the pituitary gland are way less dramatic and not nearly as instantaneous, but work in a similar fashion and are critical to your overall health and well-being. The pituitary gland is sometimes called the "master" gland of the endocrine system, because it controls the functions of all the other endocrine glands. This "Master Gland" role makes the pituitary gland quite important, despite its small size. The medical term is hypophysis (from the Greek, "lying under") which refers to the gland's position on the underside of the brain. The term "pituitary" is in reference to secretion, but has come to be synonymous with, and easier to say, than "hypophysis". The hypothalamus is the bottom part of the brain that connects and communicates with the pituitary gland via nerve fibers. This area of the brain functions as the main control center for the autonomic nervous system by regulating sleep cycles, body temperature, appetite, etc., and that acts as an endocrine gland by producing hormones, including the releasing factors that control the hormonal secretions of the pituitary gland. Regulating growth hormones are what people commonly associate the pituitary gland with. Too large an amount of these hormones causes giantism, a condition where facial features, hands, etc. become abnormally large. Too little causes dwarfism, where the overall stature of a person is very small. While the pituitary gland is responsible for regulating growth hormones, it also sends signals to the thyroid gland, adrenal glands, ovaries and testes, directing them to produce thyroid hormone, cortisol, estrogen, testosterone, and many more. These hormones have dramatic effects on metabolism, blood pressure, sexuality, reproduction, and other vital body functions, including prolactin for milk production. The pituitary gland itself is made up of three sections - Growth Hormone - Prolactin - to stimulate milk production after giving birth - ACTH (adrenocorticotropic hormone) - to stimulate the adrenal glands - TSH (thyroid-stimulating hormone) - to stimulate the thyroid gland - FSH (follicle-stimulating hormone) - to stimulate the ovaries and testes - LH (luteinizing hormone) - to stimulate the ovaries or testes - Melanocyte-stimulating hormone - to control skin pigmentation - ADH (antidiuretic hormone) - to increase absorption of water into the blood by the kidneys - Oxytocin - to contract the uterus during childbirth and stimulate milk production Each lobe of the pituitary gland produces certain hormones, each with a specific function. Pituitary problems arise when too much or too little of these hormones are produced. When an imbalance occurs, it can lead to more than a dozen disorders of the endocrine system. Deficiency of thyroid hormone, adrenal cortical hormone (cortisol) or antidiuretic hormone (vasopressin) is rapidly life-threatening. In patients with abnormalities of the other hormones, quality of life is significantly compromised. So you can see why the pituitary gland is so important! What causes the pituitary to malfunction? Tumors (typically benign), inflammation, infections and injury can cause the gland to malfunction, as well as metastasis or spread of other tumors to the pituitary (but this is very rare). Radiation therapy to the brain can also cause normal pituitary cells to malfunction. The problem with pituitary disorders is that they are hard to diagnose because they can cause a wide spectrum of symptoms, and are often confused with other disorders. Due to its location near the brain, symptoms may appear both hormonal and neurological, making diagnosis of pituitary disease difficult. Diagnosis is dependent on analyzing symptoms, signs on examination, blood tests and MRI findings as direct access to the pituitary can only be reached via surgery. Too often pituitary gland dysfunction is not suspect, and tumors can go undetected. So, why do we care? Unfortunately, research shows one out of every five people worldwide has a pituitary tumor. That is a pretty alarming statistic. We do not know why tumors are so prevalent because before October of 2002 funding for benign brain tumor research was virtually nonexistent. What we need to do now is raise awareness of pituitary disorders so that they are not misdiganosed, allowing pituitary tumors going undetected. What is a pituitary Tumor? A pituitary tumor is an abnormal growth of pituitary cells. Pituitary tumors can produce specific hormones, such as prolactin (causing infertility, decreased libido, and osteoporosis), growth hormone (causing acromegaly), ACTH (causing Cushing's), TSH (causing hypothyroidism), or be nonfunctional and not produce hormones at all. These tumors behave according to their cell of origin and are named for the specific cell type affected. For example, if a tumor originates in a prolactin producing cell, the patient develops a prolactinoma-a prolactin secreting pituitary tumor that is common and usually treatable. High prolactin levels suppress production of the pituitary hormones (luteinizing hormone and follicle stimulating hormone) that stimulate production of estrogen or testosterone. Men with these tumors have low testosterone levels and lose their sex drive and eventually their masculine characteristics such as facial hair, muscle mass, develop erectile dysfunction and low sperm count. Women with prolactin producing tumors often do not ovulate, experience low estrogen levels, and cease having menstrual periods. In both cases, patients with low sex hormones develop osteoporosis. It is important to remember that most pituitary tumors are benign and cancer is very rare. They have variable patterns of growth and affect different people in vastly different ways. Some are small and incidental, while others are small but cause hormone excess. Others may be rapidly growing mass lesions. The point is they need early detection and treatment. Enough doom and gloom - typically if diagnosed early enough the prognosis for recovery from pituitary tumors is excellent. If not, some tumors can grow into much bigger problems, ranging from discomfort to death. So early detection is key. Why is early diagnosis such a problem? In a significant minority of patients diagnosis is not made until the individual has developed debilitating or life-threatening symptoms of heart disease or adrenal (uncommon), gonadal and/or thyroid insufficiency. Even in the 21st century death from a large pituitary tumor or hormonal deficiency still occurs, albeit rarely. Early diagnosis is usually a reflection of a high index of suspicion on the part of a physician. Unfortunately, many doctors have been taught that pituitary disease is rare, so it is not at the forefront of their list of possible diagnoses. PNA is out to change all of that. Which brings us back to you - now wondering how can you get properly diagnosed. If you are suspicious of pituitary disease you should get blood and urinary hormone levels checked and, if indicated, a brain MRI, keeping in mind that microadenomas may not show up on the x-rays. Combinations of three or more of the following may suggest the possibility of a pituitary tumor: sexual dysfunction, depression, galactorrhea, infertility, growth problems, osteoporosis, obesity (specifically central), severe vision problems, easy bruising, aching joints, carpel tunnel syndrome, disrupted menses, early menopause, muscle weakness, fatigue. So if you suspect pituitary dysfunction you should get tested at a hospital with a Neuroendocrine Unit or Pituitary Testing Facility, preferably both. Pituitary blood tests can be very complicated and must be performed by specially trained technicians who can conduct dynamic hormone testing and precisely-timed blood sampling, administer testing agents, and have special expertise in measuring pituitary hormones. Its not a simple process, which is why problems often go undetected. If a tumor is found, what are the next steps? It depends on the type of tumor and how far it has invaded into the brain, as well as the patient's age and overall health. In general three kinds of treatment are used: surgery (physically removing the tumor during an operation), radiation therapy (using high-dose x-rays/proton beams to kill tumor cells) and drug therapy to shrink and sometimes eradicate the tumor. Drugs can also block the pituitary gland from making too much hormone. Surgery is a common treatment, and it is almost always successful if performed by a skilled and specialized neurosurgeon. The smaller the tumor, the greater the chance the surgery will be successful. Large tumors increase the risk of surgery and are generally associated with a lower probability of cure. Early diagnosis and treatment is the key. Post-surgery recovery in most patients is short. Patients often report immediate relief from symptoms after Transphenoidal Hypophysectomy and little pain. Some leave the hospital the same day! Radiation therapy may be used if medication and surgery fails to control the tumor. Radiation therapy uses high-energy x-rays to kill cancer cells and abnormal pituitary cells and shrink tumors. The type and size of tumor dictate treatment, and there are many. There are more than a dozen very different disorders that result from pituitary tumors and disease. OK so now maybe some of that adrenaline is in your system causing a bit of panic - so how can you tell if you have a problem? If a tumor forms in an ACTH secreting pituitary cell, it could result in the overproduction of cortisol (Cushing's Disease) or the underproduction of cortisol (adrenal insufficiency, often referred to as Secondary Addison's Disease). Cushing's is a condition characterized by excessive fat accumulation in central parts of the body (obesity, including a rounded or fat-filled face), diabetes, hypertension, a low serum potassium, thinning and bruising of skin, and osteoporosis. Symptoms of adrenal insufficiency include dehydration, low blood pressure and sodium level, and excessive weight loss. Primary Addison's Disease is caused when the adrenal glands fail to respond to directions from the pituitary and hypothalamus. If the tumor forms in a growth hormone producing cell, it can overproduce growth hormone. Tumors that form from growth hormone producing cells cause two different clinical pictures. If they occur in children before the growth plates in long bones have closed, excessive growth hormone will cause gigantism. If the growth hormone excess occurs during adulthood there is excessive enlargement of the hands, feet, and jaw, as well as soft tissue swelling of many tissues (acromegaly). Acromegaly is associated with an increased probability of developing diabetes mellitus, heart attack, hypertension, and certain types of cancer including malignancy of the colon. Most commonly the facial changes develop subtly and may not be noticed by the patient or his/her family. OK, what happens after a tumor is removed or treated? There may be permanent loss of some or all pituitary hormones, an imbalance that can be treated with Hormone Replacement Therapy. HRT can replace thyroid, growth, testosterone, or adrenal hormones when those made by the pituitary to stimulate the endocrine glands are no longer produced. It can be lifesaving therapy for the many millions of patients who need to replace hormones they no longer make. Which is to say there is quality of life after treatment! So now you know why the pituitary gland is so important, and why if you suspect pituitary dysfunction you should have yourself checked specifically for it.
In this lesson, you have learned about King James I and some of the influence he had over the arts and playwrights like William Shakespeare. You will demonstrate your understanding of this lesson by answering research questions and creating a shield for your own coat of arms. Step 1: Research heraldic symbols of the Royal Coat of Arms of King James I and answer the Royal Coat of Arms Investigation Questions in complete sentences. Royal Coat of Arms Investigation Questions What does the lion represent? Why would the rulers of England include so many of them on the Coat of Arms? What does the ? Why is it featured on the Coat of Arms of British rulers? Why is the Irish harp featured on the Coat of Arms? What does the unicorn represent? Why would the rulers of England choose a unicorn to support their shield? Why does the unicorn have a chain around its neck? The Coat of Arms includes two phrases, Blessed are the peacemakers and Shame to him who evil thinks. Choose one of these phrases and explain why a ruler might want it included in a coat of arms. Research one of the colors featured in the Coat of Arms. Based on what the color represents, explain why it would be used in a royal coat of arms. You may wish to consult some of these sources in your research or you can do some further investigation of your own. to credit any source you use with a citation. Step 2: Emblazon a shield of your own based on your values and lifestyle: Incorporate what you have learned about heraldic colors and symbols to design your shield. Also, give it a modern twist by including symbols that represent your current interests (a to an iPod, for example). You can use any program youd like to create your shield, including: design software on your computer web 2.0 tools Write a paragraph of at least five sentences explaining how all of the elements included (shape, color, and symbols) are representative of your life and your values. Your paragraph should include proper grammar, punctuation, and other language conventions. Be prepared to use your paragraph to present your shield to your instructor during your . Add your answers to the investigation questions, your shield, and your paragraph to the Symbols of Kings: .
The distinctive characteristic of a topographic map is that the shape of the Earth's surface is shown by contour lines. Contours are imaginary lines that join points of equal elevation on the surface of the land above or below a reference surface, such as mean sea level. Contours make it possible to measure the height of mountains, depths of the ocean bottom, and steepness of slopes. A topographic map shows more than contours. The map also includes symbols that represent such features as streets, buildings, streams, and vegetation. This 1:24,000 scale topographic map, also known as a 7.5 minute topographic, covers approximately 7 by 9 miles. The contours and elevations on this scale map are shown in feet. Media Type: Paper Map Location: Garfield County
The Moon, Earth’s nearest celestial neighbor, has long captivated the imagination of humanity. From the early Apollo missions to the dreams of science fiction writers, the idea of building a moon base has been an enduring fascination. In recent years, as space exploration advances and our understanding of the Moon improves, the concept of a moon base has gained traction as a viable option for expanding human presence beyond Earth. This article explores the possibilities and challenges associated with building a moon base, highlighting its potential as the next frontier of space exploration. The journey towards building a moon base is rooted in the rich history of lunar exploration. The Apollo program of the 1960s and 1970s stands as a testament to human achievement, with the successful manned moon landings capturing the world’s attention. The Apollo missions provided valuable insights into lunar geology and surface conditions, paving the way for future exploration. Lessons learned from those missions have informed our understanding of the Moon’s potential as a base for scientific research and human habitation. Advantages of a Moon Base One of the primary advantages of a moon base lies in its access to valuable resources. Recent discoveries have revealed the presence of water ice in lunar craters, which could be used to sustain human life and support various activities. Moreover, the Moon’s unique environment offers scientists an opportunity to conduct research on topics ranging from space weathering to astrophysics, pushing the boundaries of human knowledge. Additionally, the strategic location of a moon base could serve as a launchpad for further space exploration, enabling missions to Mars and beyond. Building a moon base presents numerous technological challenges that must be overcome. Transportation remains a critical aspect, as developing sustainable and cost-effective means to transport people, supplies, and equipment to the Moon is crucial. Habitat design is another significant consideration, requiring engineering solutions to ensure the safety and well-being of the crew in the harsh lunar environment. Life support systems, capable of sustaining humans in a self-contained ecosystem, are essential for long-duration stays on the Moon. The endeavor to build a moon base requires international collaboration and cooperation. Space agencies from around the world, including NASA, ESA, and other emerging players, must pool their resources and expertise. International partnerships can leverage the strengths of different nations, sharing the financial burden and technical knowledge necessary for such an ambitious undertaking. Furthermore, public-private partnerships have become increasingly vital, with private companies contributing innovative solutions and entrepreneurial approaches to moon base development. The economics of building a moon base are complex but potentially rewarding. The initial investment required for establishing the infrastructure and capabilities necessary for a sustainable lunar presence is significant. However, the economic benefits can outweigh the costs. A moon base can stimulate technological advancements, foster scientific discoveries, and provide opportunities for commercial activities such as lunar tourism, resource extraction, and space manufacturing. The economic potential of a moon base could be a driving force behind its development. As humans venture beyond Earth, it is essential to consider the environmental impact of our activities on the Moon. Preserving the lunar environment and minimizing ecological disruption should be key considerations in any moon base project. Careful planning and responsible practices are necessary to ensure that human presence on the Moon does not irreversibly harm its delicate ecosystem. By adopting sustainable approaches and employing innovative technologies, we can mitigate any negative effects and ensure the long-term preservation of the lunar environment. Ethical and Legal Issues Building a moon base raises important ethical and legal questions. The governance of lunar activities requires international agreements and regulations to ensure the responsible and equitable use of lunar resources. Questions of ownership, property rights, and the fair distribution of benefits must be addressed. Moreover, ethical considerations surrounding issues such as human rights, cultural preservation, and the impact on indigenous lunar populations (if they exist) demand thoughtful examination to ensure that lunar exploration is conducted in an ethical and inclusive manner. Looking ahead, a moon base represents the foundation for human expansion into space. Establishing a permanent human presence on the Moon is a stepping stone towards more ambitious goals, such as manned missions to Mars and beyond. A moon base could serve as a testbed for technologies, systems, and processes necessary for deep space exploration. It offers a platform for further scientific discoveries, technological advancements, and the potential for international collaboration on an unprecedented scale. The development of a moon base represents a giant leap towards a multi-planetary future. The vision of building a moon base is an exciting prospect that embodies humanity’s desire to explore and expand beyond Earth. The Moon, with its proximity and available resources, presents a unique opportunity for scientific discovery, technological advancement, and the establishment of a sustainable human presence in space. By addressing the technological challenges, fostering international collaboration, considering ethical and environmental concerns, and leveraging economic potential, we can embark on a new era of space exploration. The journey towards building a moon base will not only shape our understanding of the cosmos but also propel us towards a future where humanity becomes an interplanetary species.
Whether we believe it or not, our lives are surrounded by mixtures. For example, let’s look at the noodles we eat. We boil the noodles, mix all the veggies, and then add a tastemaker to it. This is a mixture as there is no chemical reaction taking place here. Whether it be the milk or butter we consume, or the food we eat, everything is some kind of mixture. Even the water that we drink is a mixture! We might think that drinking water is free from any other component other than H₂O, but that’s not true. Various minerals and electrolytes are present in our drinking water. Let’s talk about mixtures in a bit more detail now: WHAT IS A MIXTURE? A mixture is formed when two or more chemicals are blended in such a way that each keeps its chemical nature. Chemical bonds are not disrupted or established between the components. New physical characteristics, such as boiling and melting points, may appear in the combination. TYPES OF MIXTURE: The uniformity of mixtures and the particle sizes of components in relation to each other are used to classify them. Homogeneous mixtures have a consistent composition and phase all through their volume, but heterogeneous mixtures don’t seem to be uniform and might have a variety of phases (e.g., liquid and gas). A mixture can be classified as heterogeneous or homogeneous based on the particle size of its constituents as well: The particles in a chemical solution are exceedingly tiny. A solution is extremely stable, and sieving or centrifuging the specimen will not separate the components. Although a colloidal solution seems homogenous to the human eye, particles may be seen under a microscope. Colloids are chemically and physically stable, and the Tyndall effect may be seen in them. The Tyndall effect is the scattering of a beam of light by a medium containing small suspended particles. Decantation cannot be used to separate colloid components, although centrifugation may. Decantation occurs under the effect of Earth’s gravity and is the process of separation of liquid from solid. Centrifugation is a method of separating molecules having different densities by spinning them in solution around at high speed. In many cases, the molecules in a suspension are big enough to make the combination look heterogeneous. The Tyndall effect may be seen in suspensions. Decantation or centrifugation can be used to separate suspensions. - A mixture is formed when two or more chemicals are blended in such a way that each keeps its chemical nature. - Homogeneous mixtures have a consistent composition and phase all through their volume, but heterogeneous mixtures don’t seem to be uniform and might have a variety of phases. 1. What are the four types of mixtures? Solutions, suspensions, colloids, and emulsions are the four main types of mixtures depending on the particle size. 2. What are the types of mixtures? Heterogeneous and homogeneous mixtures are the two main types of mixtures. Homogeneous mixtures seem uniform throughout, whereas heterogeneous mixtures have clearly identifiable components. A solution, which could be a solid, liquid, or gas, is the most frequent form of homogeneous combination. 3. What is a mixture simple definition? Mixtures are substances that are made up of two or more different types of materials. Physical means can be used to separate them. A salt and water solution is one example. The separate components of any combination do not unite through any chemical reaction. We hope you enjoyed studying this lesson and learned something cool about Mixture! Join our Discord community to get any questions you may have answered and to engage with other students just like you! Don’t forget to download our app to experience our fun, VR classrooms – we promise, it makes studying much more fun! 😎 - What is a mixture?: https://byjus.com/chemistry/mixtures/ Accessed 5 Feb 2022. - Mixture Definition and Examples: https://www.thoughtco.com/mixture-definition-chemistry-glossary-606374 Accessed 5 Feb 2022. - Substances and Mixtures: https://courses.lumenlearning.com/introchem/chapter/substances-and-mixtures/ Accessed 5 Feb 2022.
Species invasions are ubiquitous in ecosystems across the world, and the Laurentian Great Lakes ecosystem is no exception. Round Goby, a small benthic fish species, have invaded each of the Great Lakes, spreading to Lake Ontario by 2002. The Great Lakes are home to a number of native fish species that are imperiled and of high conservation interest. One of these is the Lake Sturgeon, of which relatively few relict populations still persist, and for which population densities are far below historical records. This paper presents evidence that invasive Round Goby in Lake Ontario are not only eaten by Lake Sturgeon, a large-bodied benthic consumer and putative invertivore, they’ve allowed Lake Sturgeon to shift feeding ecology toward increased predation on fish at smaller size and younger age. The net effect of Round Goby on Lake Sturgeon in this system is still poorly understood: the effects of other species interactions between Round Goby and Lake Sturgeon, and the indirect effects of shifting food web structure on Lake Sturgeon are unknown. However, the shift in feeding ontogeny we document may actually have a positive effect on Lake Sturgeon access higher-quality prey (namely Round Goby) at smaller size and younger age; thereby eating more fish, and sooner. This highlights the complexity of ecosystem responses to species invasions. Though Round Goby have had a strong negative overall effect on the Great Lakes system, the shift in Lake Sturgeon feeding ecology we observe may have a positive effect on this native species. Jacobs, G. R., Bruestle, E. L., Hussey, A., Gorsky, D., & Fisk, A. T. (2017). Invasive species alter ontogenetic shifts in the trophic ecology of Lake Sturgeon (Acipenser fulvescens) in the Niagara River and Lake Ontario. Biological Invasions, 10(5), 1533–1546. https://doi.org/10.1007/s10530-017-1376-6.
On June 13, scientists aboard the NOAA Ship Ronald H. Brown set out on the West Coast Ocean Acidification Research Cruise to characterize conditions along the West Coast of North America and continue to build a unique time-series of carbon and hydrographic measurements in areas expected to be highly impacted by ocean acidification. Scientists have been collecting samples from CTDs, collecting plankton and water samples for genomics analysis, and conducting the first systematic regional survey of methane gas coming out of the thousands of seeps along the west coast. The California Current System, running along the North American west coast from British Columbia to Baja California, is a region where seasonal upwelling brings nutrient- and carbon dioxide-rich and oxygen-poor waters to the surface. Increasing levels of carbon dioxide from upwelling and anthropogenic emissions, cause a series of chemical reactions that are ultimately increasing acidity in these waters. Because it is an area with high rates of primary production by phytoplankton, air-sea carbon dioxide exchange, and carbon export to the open ocean and sediments, it is particularly susceptible to the impacts of ocean acidification and hypoxia. Understanding the progression of ocean acidification in coastal areas in the context of these other natural processes is critical for developing management, mitigation, and adaptation strategies. This 47-day research cruise brings together an international team of scientists from the United States, Canada, Mexico, Finland, and the Netherlands to measure acidity, temperature, oxygen, and chlorophyll from 16 transect lines stretching from British Columbia, Canada to San Diego, California. They also have deployed net tows to sample phytoplankton, zooplankton, and fish to analyze how the marine food web is being affected by acidified waters. With data collected from this cruise, and previous ocean acidification cruises in this region, scientists are documenting the changing ocean acidification conditions and how they are impacting marine ecosystems against a backdrop of multiple stressors including warming and deoxygenation. In 2016, measurements from this cruise demonstrated, for the first time, that ocean acidification along the US Pacific Northwest coast is impacting the shells and sensory organs of some larval Dungeness crab and that pteropods sampled near the coasts of Washington and Oregon had shells 37 percent thinner than those in waters further offshore. With the comprehensive approach taken on this year’s mission- combining detailed physical, chemical and biological measurements - we will not only better understand how our ocean is changing, but also test what new tools can be used to assess the future of these important marine ecosystems. “A strong understanding of both the changes in chemistry and marine life allows us to make informed decisions to sustain the ecosystems, communities and industry members along the West coast,” says Libby Jewett, Director of NOAA’s Ocean Acidification Program which funds this research cruise.
Drug distribution is the process of delivering a drug from the bloodstream to the tissues of the body – especially the tissue(s) where its actions are needed. The process of transferring a drug from the bloodstream to tissues is referred to as distribution. The same principles that govern drug absorption (e.g. ionization of a drug, lipophillicity of a drug, size of a drug, pH of the environment, etc.) also govern the rate and extent that a drug will distribute to various tissues in the body. In addition, there are additional factors at play, particularly non-specific binding to proteins. Commonly, drugs bind non-specifically to albumin in the plasma. Additionally, one drug, digoxin, tends to bind non-specifically to skeletal muscle, when, in fact, its desired actions occur in the heart. When drugs bind non-specifically to proteins, their movement is limited. That is because the large proteins to which they are bound will not be able to readily distribute to other parts of the body. The protein acts as a “reservoir” of sorts. As long as a drug is bound non-specifically to a protein, it cannot have a therapeutic action, nor can it be eliminated (metabolized hepatically by the liver or excreted by the kidneys). Non-specific binding to drugs can also play a role in drug-drug interactions; if two or more drugs are competing for the same binding site, one drug will displace the other, thereby, leading to potential toxicity caused by the drug that was displaced. Relevant Topics in General Science
The Featured Creatures collection provides in-depth profiles of insects, nematodes, arachnids and other organisms relevant to Florida. These profiles are intended for the use of interested laypersons with some knowledge of biology as well as academic audiences. Florida has only a few terrestrial slug species that are native (indigenous), but some non-native (nonindigenous) species have successfully established here. Many interceptions of slugs are made by quarantine inspectors (Robinson 1999), including species not yet found in the United States or restricted to areas of North America other than Florida. In addition to the many potential invasive slugs originating in temperate climates such as Europe, the traditional source of invasive molluscs for the US, Florida is also quite susceptible to invasion by slugs from warmer climates. Indeed, most of the invaders that have established here are warm-weather or tropical species. Following is a discussion of the situation in Florida, including problems with slug identification and taxonomy, as well as the behavior, ecology, and management of slugs. Slugs are snails without a visible shell (some have an internal shell and a few have a greatly reduced external shell). The slug life-form (with a reduced or invisible shell) has evolved a number of times in different snail families, but this shell-free body form has imparted similar behavior and physiology in all species of slugs. For example, slugs are not as dependent on calcium-rich environments as are shell-bearing snails, but as a result of lacking a protective shell they display behaviors that conserve moisture, such as nocturnal activity and dwelling mostly in sheltered environments. Slugs also reduce water loss by opening their breathing pore (pneumostome) only periodically instead of having it open continuously. Slugs produce mucus (slime), which allows them to adhere to the substrate and provides some protection against abrasion, but some mucus also has chemical properties that function in defense against predation (South 1992). Most slugs are hermaphroditic, possessing both male and female sex organs. Thus, at least in some species, a single individual can inseminate another slug, can be inseminated by another, and can even inseminate itself! This makes slugs particularly dangerous as invaders because even a single individual that escapes detection can establish a population in a new environment through self-fertilization. Eggs are white or translucent (though sometimes taking on a yellowish or orange-yellow tint later in egg development) and often nearly spherical. They usually are laid in clusters, either in the soil or similar locations that conserve moisture, and may be interspersed with mucus secretions. Eggs are not very resistant to desiccation, so they must remain in fairly humid environments, and absorb some water, if hatching is to be successful. Some slugs deposit fecal-like material with their eggs, but the reason for this behavior is unknown. Development time of slugs varies with weather conditions and among species, but several months or more are commonly required for slugs to reach maturity. Slugs often develop faster and commence reproduction sooner under warm conditions, but attain a larger size and ultimately produce the same number or more eggs in cooler conditions. Slugs tend to have omnivorous dietary habits. Many feed on fungi, decomposing vegetation, and soil, as well as living plant tissue. They are opportunistic, so their diets often reflects what is available, as well as innate and learned preferences. Some slugs thrive in disturbed habitats linked to human activity (anthropogenic), establishing the potential to become pests of agricultural or ornamental plants. Their nocturnal habits and ability to burrow into the soil make them difficult to detect. Their mouth contains a rasping structure called a radula, which bears tooth-like features, but these are internal and not generally visible. Young slugs may feed only on the surface of vegetation but larger slugs remove entire sections of foliage, leaving irregular holes in foliage, flowers, and other soft plant tissue. Slugs can be quite long-lived, surviving for a year or more. Unlike some invertebrates such as insects, they can continue to grow after they reach reproductive maturity and commence egg production. Thus, their adult size is quite variable. Their eggs are not all produced in a single batch; instead they are deposited periodically in soil or leaf litter. Because slugs are omnivorous, if conditions are favorable, they feed on plants, sometimes becoming pests in gardens, nurseries, and crops. They also have regulatory significance, interfering with movement of potted plants, because locations lacking slugs are not eager to be inoculated with these potentially damaging species. Florida's generally sandy soil is not conducive to slugs, but they occur where organic matter is abundant, and of course the generally humid conditions favor slug survival. A slug that commonly causes damage in Florida is the marsh slug, Deroceras laeve (Müller 1774). This small species apparently is indigenous, or at least is widespread, in North America. Deroceras laeve become most active and damaging during the cooler, wet conditions of spring and early summer and do not cause much foliage damage during the hotter months of summer, even when moisture is abundant. Damage by D. laeve often goes undiagnosed because, like all slugs, they feed only at night. Heavily mulched planting beds provide excellent harborage for this slug, including shelter during the daylight hours. Flower and foliage plants suffer the most damage in Florida, but this slug attacks many different plants. A large species known as Florida leatherleaf slug, Leidyula floridana (Leidy 1851), also inflicts injury to plants, though this species usually is not abundant. Although not usually considered to be important pests in Florida, elsewhere in the US some of the introduced European slugs have caused great damage on many vegetable, field crop, and ornamental plants. Some may transmit plant disease-causing organisms such as viruses and fungi, or serve as intermediate hosts of animal parasites, such as tapeworms and lung worms (Godan 1983). Slugs also are a threat to animals and people because they serve as intermediate hosts of the nematode Angiostrongylus costaricensis, also known as rat lungworm, which causes a disease called human abdominal angiostrongyliasis (Rueda et al. 2004). Although outbreaks of this rodent-associated disease occur in Central America, it occurs infrequently in the United States. The nematode now resides in many molluscs found in Florida, however, so the threat of disease is real (Capinera and Walden 2016). Several potentially damaging slugs have been intercepted in commerce but apparently failed to establish in Florida. These include: - black arion, Arion ater (Linnaeus 1758) - brownbanded arion, Arion circumscriptus (Johnston 1828) - gray field slug, Deroceras reticulatum (Müller 1774) - yellow garden slug, Limacus flavus (Linnaeus 1758) - giant garden slug, Limax maximus (Linnaeus 1758) - greenhouse slug, Milax gagates (Draparnaud 1801) Other species of slugs that have not been intercepted in Florida, but which threaten, include; - Spanish slug, Arion vulgaris (lusitanicus) (Moquin-Tandon 1855) - Cuban slug, Veronicella cubensis (L. Pfeiffer 1840) - bean slug, Sarasinula plebeia (Fischer 1868) - pancake slug, Veronicella sloanei (Cuvier 1817) For the most part, our native fauna remain in natural, undisturbed habitats where they function mostly as decomposers, rarely achieving pest status. However, nonindigenous slugs are increasing in visibility and importance as pests. Primarily due to international trade, nonindigenous slugs continue to be introduced to North America, so other species are likely to establish populations in Florida. Therefore, management of slugs in Florida will likely be more of a concern in the future. Slug control and management have been reviewed by many authors (e.g., Henderson and Triebskorn 2002; Bailey 2002). The management tools for slugs are much the same as used in the integrated pest management (IPM) strategies for other invertebrate pests, such as insects. However, development of chemicals and research on biological control (i.e., potential predators and parasites) have been done mostly outside of the US, and options for management are more limited than with insects. A comprehensive review of the natural enemies of terrestrial slugs can be found in Barker (2004). Natural enemies are relatively few. Some birds, especially ducks, feed on slugs. Moles and shrews also will feed on slugs. Few predaceous insects attack slugs, but in Coleoptera the larvae of Lampyridae (fireflies) and adult Carabidae (ground beetles) do so occasionally. Some parasitic flies (Diptera, especially marsh flies, family Sciomyzidae and phorid flies, family Phoridae), a few fungi, and many protozoa are known to affect slugs (Godan 1983). Phasmarhabditis hermaphrodita (Nematoda: Rhabditida), a slug-parasitic nematode used in Europe to control slugs, has not been allowed in the US because of concern about introducing a non-native organism. However, P. hermaphrodita was recently detected in the US (De Ley et al. 2014), so perhaps it will become commercially available here. Other nematodes found in the US have been investigated for slug control, but the results were not encouraging. Only recently, New Guinea flatworm, Platydemus manokwari De Beauchamp (1963) (Platyhelminthes: Tricladida: Geoplanidae) was found in Florida. A native of New Guinea, it has been accidentally spread to many locations, mostly in the Pacific region. It kills mostly snails, but also slugs. In addition to threatening some native molluscs, it also is a host of rat lungworm. Predatory snails such as the rosy wolf snail, Euglandina rosea (Férussac 1821), will attack slugs, and may account, in part, for the relatively low slug densities in Florida. Euglandina rosea prefers snails to slugs, but will attack and consume small slugs in the absence of snail prey. Euglandina rosea is native to the southeastern US, and is quite common in woodlands and gardens in Florida. It has been relocated to other parts of the world, including Hawaii, India, and many islands in the Pacific region, in an attempt to control invasive snails such as giant African land snail, Achatina fulica (Férussac 1821). It has been used to provide partial control of giant African snail, but it has been quite disruptive to native snail populations, so its use is discouraged outside its natural range (Barker 2004). Slugs benefit from having shelter such as plant debris, so removal of boards, rubbish, piles of brush, and other debris will help limit slug numbers. On the other hand, strategic placement of such shelter can be used to sample or even reduce slug populations if the slugs are removed and destroyed periodically. Moisture is also an important factor governing slug distribution and activity. Dense vegetation, deep mulch, and frequent irrigation favor slugs. Consequently, minimizing irrigation (especially overhead sprinkling) or planting drought-tolerant vegetation may reduce slug problems. When chemical control is needed, commercial slug and snail baits are usually used by scattering bait around vegetation that is to be protected. The bait contains a toxicant, of course. Traditionally, the toxicant in such baits is metaldehyde, sometimes metaldehyde plus a carbamate toxicant, or occasionally a carbamate toxicant alone. These are effective, but quite toxic, and they pose a threat to non-target organisms such as pets and vertebrate wildlife. Increasingly, they are unavailable. More recently, baits with iron-based toxicants such as iron phosphate and sodium ferric EDTA have been shown to be effective toxicants when applied to slugs and snails, and are safer to use. Boric acid and sulfur-based products have been less effective in the small number of studies that have been conducted. Regardless of the toxicant, baits should be scattered sparsely in and around vegetation, so as to make it unlikely that pets or wildlife will ingest too much of the bait. If possible, it is a good idea to irrigate prior to bait application because the additional moisture will stimulate increased slug activity, increasing the likelihood that they will eat the bait. Poisoned slugs typically display loss of coordination and paralysis, and increased mucus secretion. They often die from desiccation following paralysis, but detoxification of the poison by the slug is sometimes accomplished, so they may recover and survive (Henderson and Triebskorn 2002). Diatomaceous earth is sometimes recommended for slug control because of its purported abrasiveness, but there is no scientific evidence to support its use for slugs. Ideally, a non-toxic repellent or feeding deterrent would be available to protect vegetation, without introducing more toxicants into the environment. Two products have recently become available, both based on essential oils extracted from plants. Slug & Snail Defense™ contains a mixture of plant essential oils and pepper, but in tests with Leidyula floridana there was no protection of leaf material. On the other hand, following exposure to Snail and Slug Away™, which contains cinnamon oil as the active ingredient, considerable reduction of plant feeding was noted. Also, when sprayed directly on L. floridana slugs, Snail & Slug Away caused rapid mortality. Finally, although not labeled for management of molluscs, incidental benefits of copper hydroxide fungicide are well documented. If you are applying copper-based fungicides to your plants to control fungi or bacteria, you can anticipate that feeding by slugs on treated foliage will be greatly reduced. Copper hydroxide products with high concentrations of copper (about 60%) are most effective (Capinera and Dickens 2016). Identification of Slugs Found in Florida Superficially, most slugs appear to be quite similar, with a naked, unsegmented body covered by mucus and bearing two pairs of tentacles anteriorly, one of which bears the eyes (Figures 1 and 6). However, closer examination reveals major differences among some groups, and the slugs now in Florida are typical of this pattern. For example, veronicellid slugs are rather flattened, and have a narrow foot, and so they are fairly distinct from other slugs. However, within a slug family there can be considerable uncertainty about correct identifications and speciation. Because of the many errors in the literature involving snail and slug identification, it can be misleading to rely entirely on a literature review to assess mollusc fauna. Color is not a reliable means of identification, as some species have more than one color form. Clearly, external morphology alone is not always a reliable way to identify slugs, especially to the species level. Often it is necessary to use a combination of external traits (morphology), internal anatomy (especially reproductive structures), and even molecular diagnoses (DNA analysis) for species-level determinations. Key to the Families Following is a simple key to the families of slugs found in Florida. The variation in appearance among individual slugs makes it very difficult to identify some species with great certainty, especially when working with individual specimens. However, many species can be identified with a reasonable degree of confidence if you collect several individuals so you can assess their variation, and it is also usually necessary to collect adults. 1. Mantle covering all of the back (dorsum) of the animal, or nearly so, or saddle-like mantle structure not apparent in anterior region when body is extended (Figures 15–18); breathing pore (pneumostome) not visible or located anteriorly (toward the head) on right margin of mantle (although it may be closed) (Figure 7) . . . . . . 2 1'. Mantle consisting of an elevated saddle-like structure that is apparent when the body is extended, and located only in the anterior region of the body (Figures 19–23); breathing pore (pneumostome) present (although it may be closed) posteriorly (away from the head) on right margin of mantle (Figure 7) . . . . . . 3 2(1). Body circular or oval in cross-section, and not tapering laterally (toward the sides) (Figure 10); breathing pore (pneumostome) found near anterior right mantle edge; foot nearly as wide as body (Figure 11)—Family Philomycidae, the mantleslugs 2'. Body rather flattened in cross-section, and tapering laterally (toward the sides); breathing pore (pneumostome) not visible (Figures 15–18); foot considerably narrower than width of body (Figures 8 and 9)—Family Veronicellidae, the leatherleaf slugs 3(1'). Ridges on mantle forming fingerprint-like pattern that is not centered dorsally, rather being offset slightly to the right side of the animal—Family Agrolimacidae 3'. Ridges on mantle forming fingerprint-like pattern that is centered dorsally (Figures 22 and 23)—Family Limacidae, the keelback slugs Florida Species by Family Family Philomycidae, the Mantleslugs Carolina Mantleslug, Philomycus carolinianus (Bosc 1802) This large slug has its mantle extending the entire length of its body. It can be 3–10 cm long at maturity. Typically, it is tan with brown or black spots and blotches. In addition, there may be two rows of dark spots along the back (dorsum) (Figure 10). However, this slug can be somewhat variable in appearance and sometimes is fairly pale or mostly dark. The foot is nearly as wide as the body (Figure 11). The breathing pore (pneumostome) is located in a lightly pigmented anterior right area of the mantle (Figures 12 and 13). This slug can grow to weigh 8 g, though it becomes sexually mature and begins egg production when it is about 3 g. This species feeds on fungi. It is commonly found under logs, loose bark, and aerial bromeliads. This species normally is found in woodlands and does not frequent disturbed habitats like the veronicellid slugs. The Carolina mantleslug is a native species, found from Maine to Florida, and west to Iowa and Texas. Named subspecies exist, and it may be comprised of a species complex. An entirely albino or tan-colored form of Carolina mantleslug (Figure 14) occurs in southernmost Florida, where it lives under loose bark and feeds on fungi growing on partly submerged trunks of dead hardwood trees. Like the more common forms, it is a large slug, attaining up to 8 g in weight and 10 cm in length. Foster Mantleslug, Pallifera fosteri (F.C. Baker 1939) This is a very small slug, less than 1 cm long. Its mantle covers only the posterior 2/3 of the animal and is thicker in the anterior region of the mantle, giving the slug a hump-backed appearance (Figure 7c). Its background color is whitish or tan, but it bears numerous black spots. The spots sometimes coalesce to form blotches and may also form an interrupted irregular line laterally on the mantle. This slug occurs widely in the eastern US, but in Florida it is documented only from Marion County. Due to its small size and preferred habitat (deciduous woodlands), it may well be more broadly distributed but overlooked. In Illinois, it is reported to occur under loose bark, often in association with Philomycus carolinianus. The related but larger Megapallifera mutabilis (Hubricht 1951), also known as the changeable mantleslug, is known from counties in Alabama adjacent to Florida and may occur in the Panhandle region of Florida but so far is unreported there. Family Veronicellidae, the Leatherleaf Slugs Black-Velvet Leatherleaf, Belocaulus angustipes (Heynemann 1885) Adults of this species are uniformly black in color dorsally and velvety in appearance (Figure 15), with the underside paler in color. The velvety black color of these slugs occasionally is interrupted by a pale median stripe, especially in juveniles. The very young slugs are not so darkly colored. Because of this black velvety appearance, it is unlikely to be confused with any other slug found in Florida. It can attain a length of 5 cm when extended, but is not a large slug, attaining a weight of about 1.2 g at maturity. Like most slugs, B. angustipes is usually seen only during wet weather, spending most of its life foraging at night in leaf litter or in the soil. A native of South America, this species is now established in the states that border the Gulf of Mexico (Walls 2009), including northern and central Florida. It occurs in greenhouses and nurseries, where it can be found under potted plants, so it is destined to be spread further with nursery stock. The slug also burrows in soft soil and can enter the root-balls of plants through drainage holes at the base of the containers. This species reportedly eats both living and decayed leaves, although it is not considered to be a pest in Florida because it is not abundant. Sometimes it is found in lawns (Walls 2009) and disturbed areas near homes, such as drainage ditches. Early references refer to this species either as Angustipes ameghini (Gambetta 1923) or Veronicella ameghini (Gambetta 1923). Florida Leatherleaf, Leidyula floridana (Leidy 1851) This slug is tan dorsally and mottled with brown or black spots that often coalesce into dark dorsolateral stripes (Figures 16 and 17), and bearing a long, pale medial stripe. However, the color pattern can be quite variable. The genital pore is located adjacent to the foot (Figure 8), normally less than 1/4 hyponotal width (the hyponotum is the portion of the mantle that wraps beneath the slug body and is adjacent to the foot) from the foot. The anal slit (Figure 12) usually is visible, extending beyond the right edge of the retracted foot. It is native to the Caribbean (Cuba to Jamaica) and south Florida. Formerly found only in southern and central Florida, it has since been spread to northernmost Florida, and also is found in Louisiana, Texas, and northeastern Mexico, suggesting either that the species is more widespread than previous records indicated or that it is being relocated via commerce. Normally, it is the most commonly encountered veronicellid in Florida. No serious economic damage has been reported thus far from Florida, although they feed readily on both crop and ornamental plants and can be a nuisance. These slugs can attain a weight of 12 grams and measure over 5 cm in length. Leidyula floridana has also been known as Vaginulus floridanus (Tate 1870) and Veronicella floridana (Leidy 1851). Other Veronicellids Threatening Florida Other veronicellids have been found in Florida or may soon become established. One is Veronicella sloanei (Cuvier 1817), also known as the pancake slug. The pancake slug is large, often 5–12 cm in length, and usually very pale, ranging from whitish to tan or speckled with brown spots. Especially in juveniles, their body may bear two dorsolateral stripes extending from behind the antennae backward along the body, though they are rather diffuse. The eyestalks are bluish. In Florida, this species has been observed only in Miami-Dade County, and it is uncertain whether it persists. Elsewhere, the pancake slug is found throughout the Caribbean and on some islands in the Pacific, including Hawaii. It has a very wide host range, including many vegetables and ornamental plants. Another significant threat is Veronicella cubensis (L. Pfeiffer 1840), known as the Cuban slug. This slug is 5–12 cm long and variable in color, but usually brown with dark but thin dorsolateral stripes along its back and a thin light-colored stripe dorsally. It is very difficult to distinguish from the Florida leatherleaf slug. Like the pancake slug, it occurs widely in the Caribbean and the Pacific, where it feeds on numerous crop and ornamental plants. It has been intercepted in Florida and apparently is established in Santa Barbara County, California. Marsh Slug, Deroceras laeve (Müller 1774) This is the smallest of the common slugs in Florida, weighing as little as 0.2 g at maturity, but up to 0.8 g. It is brownish or grayish, without spots or stripes, and bears only indistinct markings, often including minute white flecks (Figures 18 and 19). Though only 1 cm long at rest, the marsh slug can become more elongate (up to 3 cm) when extended. The eggs are deposited in small clusters (often six to 10, but up to 33) in soil or organic detritus. The eggs initially are transparent but become yellowish as they mature, usually hatching in two to three weeks (Faberi et al. 2006). They are 1–3 mm long, and vary from round to oval in shape. This species is found widely in North America but also occurs in Europe, Asia, and South America. In Florida, it is found from the Keys to Pensacola, and feeds on a great number of plants in cultivated areas as well as in swamps, woodlands, and around human habitations. Although tolerant of a wide range of environmental conditions, in Florida it is inactive during the heat of the summer. Its temperature tolerances appear to be broader than that of the gray field slug, Deroceras reticulatum (Getz 1959), a much more damaging species in North America. This attribute likely explains the presence of the marsh slug in Florida but the absence of the gray field slug. Although formerly a bit confused, the scientific name and identity of D. laeve have been stable for many years. Family Limacidae, the Keelback Slugs Banded Slug, Lehmannia valentiana (Férussac 1822) This slug (also known as threeband garden slug) is larger than Deroceras laeve, attaining a length of 5–7 cm, although it begins reproduction when considerably smaller, about 2.5 cm long and 1.2 g in weight. It is light brown or reddish brown with a pair of dark dorsolateral stripes extending over the mantle and body (Figures 21–23). Despite the name 'keelback' being applied to this family, this species shows little or no evidence of a keel (dorsal ridge on the tail). Originally from southwestern Europe, it has been introduced to many states in the US, from New York to California and Hawaii, but in northern areas it is found mostly in greenhouses (Skujiené 2002). It deposits clusters containing up to 63 eggs that hatch in about 14 days. They measure 2.0–2.5 mm in length and are oval in shape. Like other problem slugs, it is anthropogenic and often found near human habitations. In Florida, it is established only in the Pensacola area. It has also been introduced to many other countries, including Australia, New Zealand, some Pacific islands, and regions of South America. The name of this species has changed repeatedly (e.g., Limax valentianus [Férrusac 1823], Limax poirieri [Mabille 1883]), and most North American records for this species refer to it as Lehmannia marginata (Hoffman 1928). Auffenburg K, Stange LA. (2008). Snail eating snails of Florida (Euglandina rosea (Férrusac 1821), Rumina decollata (Linnaeus 1758), Haplotrema concavum (Say 1821), Gulella bicolor (Hutton 1834), Varicella gracillima floridana (Pilsbry 1907). Featured Creatures. http://entnemdept.ifas.ufl.edu/creatures/misc/gastro/snail_eating_snails.htm (1 June 2011) Bailey SER. 2002. Molluscicidal baits for control of terrestrial gastropods. Pages 33–54 in Barker GM. (ed.) Molluscs as Crop Pests. CABI Publishing, Wallingford, UK. Barker GM. (ed.) 2001. The Biology of Terrestrial Molluscs. CABI Publishing, Wallingford, UK. 558 pp. Barker GM (ed.) 2002. Molluscs as Crop Pests. CABI Publishing, Wallingford, UK. 468 pp. Barker GM (ed.) 2004. Natural Enemies of Terrestrial Molluscs. CABI Publishing, Wallingford, UK. 644 pp. Capinera JL, Dickens K. 2016. Some effects of copper-based fungicides on plant-feeding terrestrial molluscs: A role for repellents in mollusc management. Crop Protection 83: 76–82. Capinera JL, Guedes Rodgrigues C. 2015. Biology and control of the leatherleaf slug Leidyula floridana (Mollusca: Gastropoda; Veronicellidae). Florida Entomologist 98: 243–253. Capinera JL, Walden HS. 2013. Rat lungworm, Angiostrongylus cantonensis (Chen, 1935) (Nematoda: Strongylida: Metastrongylida). University of Florida, Entomology & Nematology Department, EENY 570. http://entnemdept.ufl.edu/creatures/nematode/rat_lungworm.htm Cowie RH, Dillon Jr RT, Robinson DG, Smith JW. 2009. Alien non-marine snails and slugs of priority quarantine importance in the United States: a preliminary risk assessment. American Malacological Bulletin 27: 113–132. Deisler JE, Stange LA. 1984. The verocellid slugs of Florida (Gastropoda: Veronicellidae) Florida Department of Agriculture and Consumer Services Entomology Circular 261. 4 pp. De Ley IT, McDonnell RD, Lopez S, Paine TD, De Ley P. 2014. Phasmarhabditis hermaphrodita (Nematoda: Rhabditidae), a potential biological control agent isolated for the first time from invasive slugs in North America. Nematology 16: 1129–1138. Faberi AJ, López AN, Manetti PL, Clemente NL, Álvarez Castillo HA. 2006. Spanish Journal of Agricultural Research 4: 345–350. Garcia EN, Thomé JW, Castillejo J. 2007. A review of the Veronicellidae from Mexico (Gastropoda: Soleolifera). Revista Mexicana de Biodiversidad 78: 41–50. Getz LL. 1959. Notes on the ecology of slugs: Arion circumscriptus, Deroceras reticulatum, and D. laeve. American Midland Naturalist 61: 485–498. Henderson I, Triebskorn R. 2002. Chemical control of terrestrial gastropods. Pages 1-31 in Baker, GM. (ed.) Molluscs as Crop Pests. CABI Publishing, Wallingford, UK. Jacksonville Shell Club. Northeast Florida slug page. http://www.jaxshells.org/807b.htm (1 June 2011) Karlin EJ, Bacon C. 1961. Mating, and egg-laying behavior in the Limacidae (Mollusca). Transactions of the American Microscopical Society 80: 399–406. Rueda A. 1989. Biology, Nutritional Ecology, and Natural Enemies of the Slug Sarasinula plebeia (Fischer,1868) (Soleolifera: Veronicellidae). Unpublished M.S. Thesis, University of Florida, Gainesville. 163 pp. Rueda A, Caballero R, Kaminsky R, Andrews KL. 2004. Vaginulidae in Central America, with emphasis on the bean slug Sarasinula plebeia (Fischer). Pages 115–144 in Barker, G.M. (ed.) Molluscs as Crop Pests. CABI Publishing, Wallingford, UK. 468 pp. Robinson DG. 1999. Alien invasions: the effects of the global economy on non-marine gastropod introductions into the United States. Malacologia 41: 413–438. South A. 1992. Terrestrial Slugs: Biology, Ecology and Control. Chapman and Hall, London. 428 pp. Skujiené G. 2002. Lehmania valentiana (Férussac 1823) - a newly introduced slug species in Lithuania (Gastropoda: Pulmonata: Limacidae). Act Zoologica Lituanica 12: 341–344. Walls JG. 2009. Just a plain black slug: Belocaulus angustipes. American Conchologist 37: 28–29. White-McLean J, Capinera JL. 2014. Some life history traits and diet selection in Philomycus carolinianus (Mollusca: Gastropoda: Philomycidae). Florida Entomologist 97: 511–522.
Effects of Climate Change in Missouri a food supply. We’ll also look at how urban heat islands can be affected by this global problem. This article will be a useful tool for those who are concerned about the effects of climate change in Missouri. Impacts of climate change on human health Climate change is already affecting Missouri and its population. The state’s temperatures have risen between 0.5 and 2 degrees Fahrenheit in the past century. Climate change is predicted to worsen hazard events like flooding and drought and result in higher temperatures and more frequent wildfires. This will affect human health in many ways, including increased air pollution, shortened pollen seasons, and elevated stress levels. Extreme weather conditions cause a wide range of health effects, ranging from decreased work performance to increased depression. These impacts may also affect people’s sense of self-esteem and interpersonal relationships. Additionally, more frequent and intense floods and droughts can reduce the amount of drinking water available for residents. The effects of climate change on human health aren’t limited to Missouri, though. As temperatures continue to rise, more natural disasters may occur, including floods, droughts, and mudslides. The Center for Community Health Partnership and Research supports Environment Missouri in addressing the impacts of global warming on the health of its residents. The center provides information and educational materials about climate-related health risks and educates residents, community groups, and policymakers about the risks associated with global warming. Sadly, this administration’s actions fuel the climate crisis and negatively affect the lives of American citizens in all 50 states. For example, in the past three years, Missouri experienced nine major storms, three floods, and one drought, with a combined $1 billion worth of losses. A city like Kansas City is expected to experience an increase of four degrees Fahrenheit in annual average temperature. As Kansas City already has a high energy burden, the additional heat and humidity will add to its electric bill. Moreover, city dwellers are particularly vulnerable to heat and humidity. The urban heat island effect increases the likelihood of heat and humidity in the city. For this reason, people living in low-income areas and in the urban core are more likely to suffer from heat-waves. The NIH is pursuing a comprehensive understanding of the effects of climate change on the health of individuals and communities across the country. The agency has also initiated a program that aims to curb the impacts of climate change in Missouri. However, the plan is currently lacking in clarity. Despite this, the Obama administration is encouraging communities to adopt sustainable practices and programs in response to climate change. This will make the climate-change problem more manageable and more likely to benefit all citizens. Currently, the average temperature of Missouri is expected to rise by 3 degrees Fahrenheit by the year 2100. That’s comparable to what Pharr, Texas currently experiences in the summer. In the 1980s, Missouri saw about 100 mosquito-friendly days per year. By 2006, that number increased to 131 days. With more mosquitoes, there is an increased risk of various diseases caused by mosquitoes. Also, the Trump administration recently released a final rule to eliminate 2020 fuel efficiency standards. This decision will lead to higher greenhouse gas emissions and cost Missouri residents $571 million annually. Impacts of climate change on food systems In addition to affecting the safety of our food, climate-related disruptions can disrupt the transportation, storage, and distribution of our food. Most grains are transported by water. Extreme weather events disrupt waterways, and those that don’t cause floods or droughts can affect alternate transportation routes. The summer drought of 2012 in the United States had devastating effects on the Mississippi River watershed, one of the most important transcontinental shipping routes for agriculture. The rising temperatures are threatening our food supply, and this could make severe food shortages even more likely. As the global temperature rises, yields of staple crops, such as maize, will decline. Maize is used in countless products, and it feeds livestock worldwide. Climate change is already causing stress in many large grain-producing regions. The agricultural industry will be hampered if it can’t adapt to changing climate. Increased rainfall, rising temperatures, and decreasing soil moisture are all threatening our crops. Climate change also affects food prices, consumption patterns, and insurance. Because of the risks associated with climate change, all stakeholders need to adopt relevant policies to address its impacts. This way, farmers can produce enough food to feed the projected 9.8 billion people in the world by 2050. This will contribute to sustainable development goal number two. Native and Indigenous producers can also be affected by the climate crisis. Native producers have limited access to land and face more challenges with credit than non-Natives. In addition, they are often affected by greater impacts of climate disruption. Therefore, Indigenous-owned food businesses can play an integral role in addressing the issues of climate change. These businesses are essential for Native communities, including the Cheyenne River Sioux Indian reservation. The Resilience Project coordinator Jim Worstell recently finished a three-year research project to develop an index that rated the resilience of agricultural systems in all U.S. counties. He will discuss the impacts of climate change, COVID-19, and market volatility on agriculture. Jim will also give historical perspectives on homegrown nourishing food during pandemics. If you’re interested in attending this symposium, make sure to register early and be prepared to learn a lot about the topic. Warmer winters and spring temperatures are affecting agriculture in the state. In Missouri, farmers are often prevented from planting in the spring and harvesting in the fall due to excessive moisture. In addition, heavier rains also wash nutrients downstream, fueling the lifeless “dead zone” in the Gulf of Mexico. Meanwhile, warm temperatures increase the risk of crop diseases, which will reduce yields. Fortunately, there are ways to combat climate change and the impacts of climate change on Missouri’s food systems. Increased temperature is a direct result of climate change, which will increase droughts and hot temperatures. In addition, higher temperatures can lower crop yields and kill many species of fish and shellfish. Changing climate patterns affect the natural ecosystem, and a healthy balance between the two is essential to sustain the state’s food supply. And, a strong impact of these changes on the food supply and safety is already evident. Impacts of climate change on urban heat islands In addition to the urban heat island problem in St. Louis, Missouri faces the growing number of extreme heat days caused by climate change. There are four times more three-day heat waves each year in the Midwestern city than there were in the 1940s. And the nighttime temperatures are rising faster than they are during the day, which has an adverse effect on health and the economy. The Trump administration is trying to gut the cumulative impact requirement in the National Environmental Policy Act, which calls for climate considerations when developing major infrastructure projects. Thankfully, many cities are making efforts to combat the problem. One example of a climate action plan is Phoenix, Arizona. The city is working with residents and advocates to develop a plan that protects vulnerable communities while reducing the impact of urban heat islands. The city hopes to have a complete climate protection plan in place by early next year. But until then, it will have to rely on existing climate protection strategies and innovative technologies for urban heat island mitigation. A number of local communities, including St. Louis, are using these plans to implement climate action and adaptation measures. Because the heat islands of St. Louis and other cities have more urban heat than outlying regions, they are more susceptible to extreme heat events. While the sun may not be directly responsible for the increase in temperature, buildings and pavement radiate heat long after it has set. Areas with lots of trees and other vegetation are cooler due to shade and evapotranspiration (water evaporation from the leaves). While St. Louis may be warmer than surrounding areas, the temperature in the city remains consistent throughout the day. The extreme temperatures and increased flooding that accompany climate change are two of the key indicators that warn of global warming. The impact of urban heat islands is not just physical, but also health-related. While the problems caused by urban heat islands may be far-reaching, solutions are still under study. The impact of climate change on urban heat islands is already affecting the lives of people in the area. It will become a major public health issue. In Kansas City, the National Oceanic and Atmospheric Administration is funding a campaign to map the city’s urban heat islands. This mapping is part of a national effort to help cities combat this problem. The underlying problem is related to the broader climate change concerns. The Kansas City Office of Environmental Quality is collaborating with NOAA on the project. The results of the mapping project will be used to develop climate protection plans and resiliency plans. One study in Kansas City showed that people living in low-income areas spent more money on energy than those in higher-income neighborhoods. In fact, low-income households in Kansas City spent 8.5% of their income on energy costs compared to households in higher-income areas. The findings were consistent across cities and regions in the past two years. In addition, the EPA found a similar correlation between energy costs and heat island impacts in their recent study.
Plants require carbon dioxide to survive. Most plants prefer carbon 12 isotope over the carbon-13 isotope. This preference is due to the fact that carbon-12 is lighter and easier for plants to process than carbon-13. Carbon-12 has six protons and six neutrons, while carbon-13 has six protons and seven neutrons. The extra neutron in carbon-13 makes it slightly heavier and less abundant in the environment. This difference in weight makes it more difficult for plants to incorporate carbon-13 into their metabolic processes, which is why they prefer carbon-12. This preference for carbon-12 has implications for the study of plant physiology and ecology. Understanding why plants prefer carbon-12 can help researchers better understand how plants function and how they interact with their environment. Additionally, it can have practical applications in fields such as agriculture and climate science. Carbon 12 vs Carbon 13 Isotopes of Carbon Carbon is a chemical element that has two stable isotopes: Carbon-12 and Carbon-13. The difference between these isotopes is in the number of neutrons they have in their atomic nuclei. Carbon-12 has 6 neutrons, while Carbon-13 has 7 neutrons. Plants prefer Carbon-12 over Carbon-13 because it is lighter and easier to use in photosynthesis. When plants absorb carbon dioxide from the atmosphere, they use an enzyme called Rubisco to convert it into organic molecules. Rubisco works more efficiently with Carbon-12 than with Carbon-13, allowing plants to produce more organic matter with less energy. Carbon-12 is also more abundant in the environment than Carbon-13. About 99% of all carbon on Earth is Carbon-12, while Carbon-13 makes up only 1% of the total carbon pool. This means that plants have a much larger pool of Carbon-12 to draw from than Carbon-13, making it more advantageous for them to use Carbon-12. In addition, Carbon-13 is more expensive for plants to use in photosynthesis because it requires more energy to break the bonds between the carbon and oxygen atoms. This energy cost is known as the photorespiratory penalty, and it reduces the efficiency of photosynthesis. By using Carbon-12 instead, plants can avoid this penalty and maximize their energy production. Overall, the preference of plants for Carbon-12 over Carbon-13 is a result of the isotope’s lighter weight, greater abundance, and lower energy cost. This preference has important implications for the global carbon cycle and the role of plants in mitigating climate change. Photosynthesis and Carbon 12 Plants use photosynthesis to convert light energy into chemical energy, which they can use for growth and other metabolic processes. During photosynthesis, plants absorb carbon dioxide (CO2) from the air and water from the soil. They then use the energy from sunlight to convert the CO2 and water into glucose and oxygen. The process of photosynthesis involves two stages: the light-dependent reactions and the light-independent reactions. During the light-dependent reactions, light energy is absorbed by pigments in the plant’s chloroplasts, which then convert the light energy into chemical energy in the form of ATP and NADPH. These energy-rich molecules are then used in the light-independent reactions to convert CO2 into glucose. One reason why plants prefer carbon 12 is that it is the most common isotope of carbon found in the environment. Carbon 12 makes up about 98.9% of all carbon on Earth, while carbon 13 and carbon 14 make up only 1.1%. Since plants absorb carbon dioxide from the air during photosynthesis, they are more likely to absorb carbon 12 than the other isotopes. Another reason why plants prefer carbon 12 is that it is easier for them to use in the photosynthesis process. Carbon 12 has six protons and six neutrons, while carbon 13 has seven neutrons and carbon 14 has eight neutrons. The extra neutrons in carbon 13 and carbon 14 make them slightly heavier than carbon 12, which can make it more difficult for plants to incorporate them into glucose molecules. In summary, plants prefer carbon 12 because it is the most common isotope of carbon in the environment and because it is easier for them to use in the photosynthesis process. Carbon 12 Abundance Natural Abundance of Carbon 12 Carbon is a crucial element for life on Earth. It is the building block of all organic molecules, and it is a key component of the atmosphere, oceans, and rocks. Carbon has three isotopes: carbon-12, carbon-13, and carbon-14. Carbon-12 is the most abundant carbon isotope, making up about 99% of all carbon on Earth. The reason why plants prefer carbon-12 is due to its natural abundance. Carbon-12 has six protons and six neutrons, which makes it the most stable carbon isotope. The other two isotopes, carbon-13 and carbon-14, are less abundant and less stable. Carbon-13 has one extra neutron, which makes it slightly heavier than carbon-12. Carbon-14 has two extra neutrons, which makes it even heavier and unstable. Plants use carbon dioxide from the atmosphere during photosynthesis to produce organic molecules. Carbon dioxide is composed of one carbon atom and two oxygen atoms. Since carbon-12 is the most abundant carbon isotope, it is more likely to be used by plants during photosynthesis. This is because plants prefer to use the most abundant and stable form of carbon available to them. In conclusion, the natural abundance of carbon-12 is the main reason why plants prefer it over the other carbon isotopes. The stability and abundance of carbon-12 make it the most favorable isotope for plants to use during photosynthesis. Impact of Carbon 13 on Plants Carbon-13 is a stable isotope of carbon, which is less abundant in nature than carbon-12. Plants absorb both carbon-12 and carbon-13 from the atmosphere through photosynthesis. However, the preference of plants for carbon-12 over carbon-13 is well-known among researchers. Studies have shown that plants prefer carbon-12 over carbon-13 because it is lighter and easier to process. Carbon-13 has an extra neutron, which makes it heavier than carbon-12. As a result, plants have to spend more energy to process carbon-13, which affects their growth and development. Furthermore, the presence of carbon-13 in the atmosphere can also affect the carbon isotope composition of plants. In areas with high levels of carbon-13, plants tend to have a higher carbon-13 to carbon-12 ratio. This can have implications for carbon isotope studies in ecology and other fields. In addition, carbon-13 can also be used as a tracer in plant research. Researchers can label plants with carbon-13 and track its movement within the plant or between plants. This technique can provide valuable insights into plant physiology and ecology. Overall, while carbon-13 is essential for plant growth and development, plants prefer carbon-12 due to its lighter weight and easier processing. The impact of carbon-13 on plants can have implications for carbon isotope studies and can also be used as a tracer in plant research. Frequently Asked Questions How does the ratio of carbon-12 to carbon-13 affect plant growth? The ratio of carbon-12 to carbon-13 affects plant growth because plants prefer to use carbon-12 in their metabolic processes. Carbon-12 is more abundant in the environment and easier for plants to assimilate. When the ratio of carbon-12 to carbon-13 is low, plants may struggle to obtain enough carbon-12 for their needs, which can lead to reduced growth and yield. What is the significance of carbon-12 in photosynthesis? Carbon-12 is significant in photosynthesis because it is the primary source of carbon for plants. During photosynthesis, plants use energy from sunlight to convert carbon dioxide into organic compounds, such as sugars and starches. Carbon-12 is preferred because it is more stable and easier for plants to use than carbon-13. How does carbon-12 impact plant metabolism? Carbon-12 impacts plant metabolism by serving as the main source of carbon for the production of organic compounds. Plants use carbon-12 to produce sugars, starches, and other essential molecules that are necessary for growth and survival. Carbon-12 is preferred because it is more abundant and easier for plants to assimilate than other isotopes of carbon. What is the role of carbon-12 in plant respiration? Carbon-12 plays a critical role in plant respiration by providing the carbon needed for the production of energy. During respiration, plants break down organic compounds to release energy that is used for various cellular processes. Carbon-12 is preferred because it is more stable and easier for plants to use than other isotopes of carbon. Are there any drawbacks to using carbon-13 instead of carbon-12 in plant research? There are some drawbacks to using carbon-13 instead of carbon-12 in plant research. Carbon-13 is less abundant in the environment, which makes it more expensive to use in experiments. Additionally, plants may not assimilate carbon-13 as efficiently as carbon-12, which can lead to inaccurate results. How do carbon-12 and carbon-13 isotopes affect plant ecology? Carbon-12 and carbon-13 isotopes can affect plant ecology by providing information about the sources of carbon that plants use in different environments. By analyzing the ratio of carbon-12 to carbon-13 in plant tissues, researchers can determine the types of carbon sources that plants are using, such as atmospheric carbon dioxide or soil organic matter. This information can help us better understand plant ecology and the cycling of carbon in ecosystems.
Rocky Mountain elk roam widely across the Upper Rio Grande watershed, traveling extensively from high summer range in the mountains to the shrubland and deserts at lower elevations in the colder months. They are highly social animals and gather in herds for security, seeking areas away from roads and other disturbances. Elk have several protected areas to use as refuge in the Upper Rio Grande, such as the Sangre de Cristo Mountains, South San Juan wilderness areas and the Great Sand Dunes National Park in Colorado. In New Mexico, they can be found in the Valles Caldera National Preserve, Valle Vidal, Rio Grande Del Norte National Monument and the Columbine-Hondo Wilderness Area. Even with the abundant habitat in each of these areas, elk migrate seasonally. The pathways elk and other wildlife use are full of obstacles such as demanding topography, industrial development and roads. One major impediment is US Highway 285 through Carson National Forest, which presents a significant obstacle for elk attempting to reach critical habitat in the Rio Grande Del Norte National Monument. Understanding what elk and other key wildlife need to thrive– and then implementing management activities to meet those needs — is critical to maintaining robust elk populations in the Upper Rio Grande.
It’s finally here: Scientists have reported the discovery of the first room-temperature superconductor, after more than a century of waiting. Now, scientists have found the first superconductor that operates at room temperature — at least given a fairly chilly room. The material is superconducting below temperatures of about 15° Celsius, physicist Ranga Dias of the University of Rochester in New York and colleagues report October 14 in Nature. Dias and colleagues formed the superconductor by squeezing carbon, hydrogen and sulfur between the tips of two diamonds and hitting the material with laser light to induce chemical reactions. At a pressure about 2.6 million times that of Earth’s atmosphere, and temperatures below about 15° C, the electrical resistance vanished. "In The Beginning Was The Word, And The Word Was Aardvark."
Learn about the nature of terrorism. - Terrorists often choose targets that offer little danger to themselves and areas with relatively easy public access. - Foreign terrorists look for visible targets where they can avoid detection before or after an attack such as international airports, large cities, major international events, resorts, and high-profile landmarks. Learn about the different types of terrorist weapons including explosives, kidnappings, hijackings, arson, and shootings. Prepare to deal with a terrorist incident by adapting many of the same techniques used to prepare for other crises. - Be alert and aware of the surrounding area. The very nature of terrorism suggests that there may be little or no warning. - Take precautions when traveling. Be aware of conspicuous or unusual behavior. Do not accept packages from strangers. Do not leave luggage unattended. - Learn where emergency exists are located. Think ahead about how to evacuate a building, subway or congested public area in a hurry. Learn where staircases are located. - Notice your immediate surroundings. Be aware of heavy or breakable objects that could move, fall or break in an explosion. Preparing for a Building Explosion The use of explosives by terrorists can result in collapsed buildings and fires. People who live or work in a multi-level building can do the following: - Review emergency evacuation procedures. Know where fire exits are located. - Keep fire extinguishers in working order. Know where they are located, and how to use them. Learn first aid. Contact the local chapter of the American Red Cross for additional information. - Keep the following items in a designated place on each floor of the building. - Portable, battery-operated radio and extra batteries - Several flashlights and extra batteries - First aid kit and manual - Several hard hats - Fluorescent tape to rope off dangerous areas If you receive a bomb threat, get as much information from the caller as possible. Keep the caller on the line and record everything that is said. Notify the police and the building management. After you've been notified of a bomb threat, do not touch any suspicious packages. Clear the area around the suspicious package and notify the police immediately. In evacuating a building, avoid standing in front of windows or other potentially hazardous areas. Do not restrict sidewalk or streets to be used by emergency officials. In a building explosion, get out of the building as quickly and calmly as possible. If items are falling off of bookshelves or from the ceiling, get under a sturdy table or desk.If there is a fire. - Stay low to the floor and exit the building as quickly as possible. - Cover nose and mouth with a wet cloth. - When approaching a closed door, use the palm of your hand and forearm to feel the lower, middle and upper parts of the door. If it is not hot, brace yourself against the door and open it slowly. If it is hot to the touch, do not open the door--seek an alternate escape route. - Heavy smoke and poisonous gases collect first along the ceiling. Stay below the smoke at all times. If you are trapped in debris. - Use a flashlight. - Stay in your area so that you don't kick up dust. Cover your mouth with a handkerchief or clothing. - Tap on a pipe or wall so that rescuers can hear where you are. Use a whistle if one is available. Shout only as a last resort--shouting can cause a person to inhale dangerous amounts of dust. - Untrained persons should not attempt to rescue people who are inside a collapsed building. Wait for emergency personnel to arrive. Chemical agents are poisonous gases, liquids or solids that have toxic effects on people, animals or plants. Most chemical agents cause serious injuries or death. Severity of injuries depends on the type and amount of the chemical agent used, and the duration of exposure. Were a chemical agent attack to occur, authorities would instruct citizens to either seek shelter where they are and seal the premises or evacuate immediately. Exposure to chemical agents can be fatal. Leaving the shelter to rescue or assist victims can be a deadly decision. There is no assistance that the untrained can offer that would likely be of any value to the victims of chemical agents. Biological agents are organisms or toxins that have illness-producing effects on people, livestock and crops. Because biological agents cannot necessarily be detected and may take time to grow and cause a disease, it is almost impossible to know that a biological attack has occurred. If government officials become aware of a biological attack through an informant or warning by terrorists, they would most likely instruct citizens to either seek shelter where they are and seal the premises or evacuate immediately. A person affected by a biological agent requires the immediate attention of professional medical personnel. Some agents are contagious, and victims may need to be quarantined. Also, some medical facilities may not receive victims for fear of contaminating the hospital population.
Our DT curriculum is designed to encourage children to develop their creativity and imagination through designing, making and evaluating products which solve real and relevant problems and include making relevant links. Throughout this curriculum children will be encouraged to consider their own and other's needs, wants and values whilst being encouraged to select appropriate tools and techniques for making a product, whilst following safe procedures. Our design technology curriculum is designed to ensure progression in knowledge and skills across all year groups. It incorporates the key elements of designing, making, and evaluating products. The curriculum is planned and sequenced, building on prior knowledge and providing opportunities for consolidation and extension. We use the process of IDEA, FPT, design, make, evaluate across the school. Design technology is integrated with other subjects, such as science, art, geography, history and computing, creating meaningful links and promoting a holistic understanding of the subject. We have a strong commitment to inclusion and ensure that our design technology curriculum caters to the needs of all learners. Differentiated tasks and resources are provided to support and challenge pupils of varying abilities. We promote gender equality and actively encourage both boys and girls to engage with design technology, challenging stereotypes and promoting diversity. Our design technology curriculum is enriched with engaging projects and challenges that help children to understand real-world design scenarios. Pupils are given opportunities to identify, define, and tackle design problems, encouraging them to think critically and creatively. They are also encouraged to evaluate and refine the products they design and make. Every class has a half term cooking session with an outside company to ensure that they get high quality teaching for food preparation and nutrition. All children are able to learn the life skill of cooking. There is also an after school cookery club for this who wish to further their skills. The impact of our design technology curriculum is evident in our pupils' positive engagement, progress, and achievement, along with their enhanced skills, knowledge, and understanding. They exhibit increased confidence and independence in their design decisions and show a willingness to take risks and learn from failures. Pupils' work reflects an understanding of the design process, showcasing their ability to generate, develop, and refine ideas to produce a quality finished piece of work. Our cookery lessons mean that children have confidence and skills which they can take in to adulthood,

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