Santa Barbara Song Sparrow Facts

Santa Barbara Song Sparrow Facts The Santa Barbara Song Sparrow (Melospiza melodia graminea, sensu) is a now-extinct subspecies of song sparrow that lived on Santa Barbara Island in California and was most closely related to the Channel Island Song Sparrow (Melospiza melodia graminea). It was one of the smallest of the 23 subspecies of song sparrows and had a perky short tail. Fast Facts: Santa Barbara Song Sparrow Scientific Name: Melospiza melodia graminea, sensuCommon Name: Santa Barbara Song SparrowBasic Animal Group: BirdSize: 4.7–6.7 inches; wingspan 7.1–9.4 inchesWeight: 0.4–1.9 ouncesLifespan: 4 yearsDiet:  OmnivoreHabitat: On Santa Barbara Island, Channel Islands, CaliforniaPopulation: 0Conservation Status: Extinct Description There are 34 subspecies of song sparrows in the world: It is one of the most polytypic birds in North America, with a good deal of variation, especially in geographically restricted species. The Santa Barbara Song Sparrow resembled other similar subspecies  and is described as most closely resembling the Heermanns Song Sparrow (Melospiza melodia heermanni). It was one of the smallest song sparrow subspecies and was characterized by a particularly gray back with dark streaks. Most song sparrows are browner in color with dark streaks. In general, a song sparrows breast and belly are white with dark streaking and a dark brown spot in the middle of the breast. It has a brown-capped head and a long, brown tail that is rounded on the end. The sparrows face is gray and streaked. The Santa Barbara song sparrows were distinguished from other song sparrows by a smaller, more slender bill, and a tail which was shorter than the wing. Habitat and Range The Santa Barbara Song Sparrow was known to exist only on 639-acre Santa Barbara Island (the smallest of the Channel Islands) in Los Angeles County, California. The sparrows natural habitat on the island was much like the habitat of other species of the song sparrow, which are generally abundant and adaptable on the mainland United States. Habitat components on the island that the sparrow relied on included: Thickets of shrubs like sagebrush, dense grasslands, and other scrubby vegetation for nesting and shelter (cover)Food resources such as giant coreopsis (Coreopsis gigantean, also called the tree sunflower), the Santa Barbara Island live-forever, shrubby buckwheat, and chicoryStanding or running fresh water or a consistent source of moisture from fog or dew Diet and Behavior In general, song sparrows are known to frequently forage on the ground and also in low vegetation where they are protected from predators by thickets and shrubs. Like other song sparrow species, the Santa Barbara Song Sparrow ate a variety of plant seeds and insects (including beetles, caterpillars, bees, ants and wasps, and flies). In spring, during the periods of nesting and rearing of young, insects increased in terms of the important components of the sparrows diet. The year-round diet of song sparrows in California is 21 percent insects and 79 percent plants; the song sparrow also eats crustaceans and mollusks on the coasts. Reproduction and Offspring Based on extant species of song sparrows on San Miguel, Santa Rosa, and Anacapa islands in the Channels, the Santa Barbara song sparrow built compact, open nests of twigs and other plant material, which were optionally lined with grass. The female laid three broods per season, each between two to six red-brown marked, pale green eggs. Incubation ranged from 12–14 days and was tended to by the female. Both parents were involved in the feeding until the sparrows were fledged 9–12 days later.   The birds were serially and simultaneously polygamous, and DNA studies showed that 15 percent or more of the young were sired outside the social pair. Extinction Process During the first half of the 20th century, sparrow nesting habitat (scrub vegetation) on Santa Barbara Island began disappearing as a result of clearing land for farming and from browsing by introduced goats, European rabbits, and New Zealand red rabbits. Unnatural predation also threatened sparrows during this time, after the introduction of domestic cats to the island. The sparrows natural predators included the American Kestrel (Falco sparverius), Common Raven (Corvus corax), and Loggerhead Shrike (Lanius ludovicianus). Even with these new challenges to its survival, the song sparrows maintained a viable population through the summer of 1958. Unfortunately, a large fire in 1959 destroyed most of the sparrows remaining habitat. The birds are thought to have been extirpated from the island during the 1960s because years of intensive surveys and monitoring throughout the 1990s did not reveal any resident song sparrows on the island. The U.S. Fish and Wildlife Service officially determined that the Santa Barbara Song Sparrow was extinct and removed it from the endangered species list on October 12, 1983, citing a loss of habitat and predation by feral cats. Sources Arcese, Peter et al. Song Sparrow Melospiza melodia. Birds of North America: Cornell Lab of Ornithology, January 1, 2002.  BirdLife International 2016. Melospiza melodia. The IUCN Red List of Threatened: e.T22721058A94696727, 2016. Santa Barbara song sparrow (Melospiza melodia . ECOS Environmental Conservation Online System, U.S. Fish and Wildlife Service.  graminea: Delisted due to ExtinctionVan Rossem, A. J. â€Å"A Survey of the Song Sparrows of the Santa Barbara Islands.† The Condor 26.6 (1924): 217–220.Zink, Robert M., and Donna L. Dittmann. Gene Flow, Refugia, and Evolution of Geographic Variation in the Song Sparrow (Melospiza Melodia). Evolution 47.3 (1993): 717–29.

Word Choice Formally vs. Formerly Proofeds Writing Tips

Word Choice Formally vs. Formerly Proofeds Writing Tips Word Choice: Formally vs. Formerly A lot of adverbs end with the letters â€Å"-ly.† This does, unfortunately, mean that some unrelated words sound quite similar, such as â€Å"formally† and â€Å"formerly.† So to make sure you can use these terms correctly, check out our guide to what â€Å"formally† and â€Å"formerly† actually mean. Formally (In a Formal Manner) â€Å"Formally† is the adverbial form of the adjective â€Å"formal.† And since â€Å"formal† means â€Å"official† or â€Å"in accordance with convention,† we use â€Å"formally† when something is done in a formal manner. To dress â€Å"formally,† for example, usually means dressing smartly for a special occasion: We dressed formally for the wedding. Alternatively, we could make a â€Å"formal† announcement. This would be a statement that makes something official (even if people already knew about it through hearsay): He formally announced his resignation on Tuesday. The opposite of â€Å"formally† is â€Å"informally.† This implies doing something in a way that ignores official rules or conventions. The adjectival form is this word, meanwhile, is â€Å"informal.† Formerly (Previously) The word â€Å"formerly† means â€Å"in the past† or â€Å"previously.† For example: The Google search engine was formerly called â€Å"Backrub.† Here, we’re saying that Google was called â€Å"Backrub† before it was Google (which is true, weirdly). The adjectival form of this word is â€Å"former,† which means â€Å"from a past time.† All in all, its probably a good thing they changed it. Formally or Formerly? Although these words sound similar, they don’t mean the same thing. As such, you should be careful not to mix them up in your writing. Remember: Formally comes from â€Å"formal† and means â€Å"officially† or â€Å"in a formal way.† Formerly comes from â€Å"former† and means â€Å"previously† or â€Å"in the past.† Since the words â€Å"formal† and â€Å"former† sound more distinct, moreover, you can use them to remind you what their adverbial forms mean. And if you want to be sure that your word choice is always correct in your writing, a little bit of proofreading can be a big help!

Expansion & growth is the topic to write about Essay

Expansion & growth is the topic to write about - Essay Example Later, in the 16th century, California became under the control of Spanish and British colonizers. Gradually, the settlers began to control the indigenous population. The Bear Flag Revolt in the year 1846 in California is symbolic of the rebellious attitude of the settlers and the formation of California Republic. The California Gold Rush (say, between1848 and1855) is another major period in the history of California. During this period, the influx of immigrants in search of gold changed the distribution of population in California. Later, the Compromise of 1850 led to the formation of California as a free state within the United States of America. Earlier than European colonization, California was sparsely populated because the Native Americans used to settle in different areas of California. The European settlement resulted influx of immigrants and rapid urbanization. To be specific, the California Gold Rush or the influx of gold-seekers resulted in the rapid urbanization of California. The small settlements in California rapidly transformed into towns and cities. Now, California enjoys the largest gross state product (GSP) among the states within the United States of America. Ignacio Gonzalez stated that â€Å"In February 2001, California’s unemployment rate dropped to 4.5 percent, the lowest level since the late 1960s† (351). The growth in GSP is most important because it represents the expansion and growth of California. In the present condition, the Californian economy depends upon international trade and commerce. Transportation facilities in California consist of the network of roads (freeways, expressways and highways), airways (commercial and general aviation), seaports (for example, Port of Los Angeles) and rail lines (intercity rail lines, light rail systems etc). Summing, the expansion and growth of California from a small settlement area to a free state and its development is interconnected

Personal statement for university approval Example | Topics and Well Written Essays - 250 words

For university approval - Personal Statement Example ering developed from the position of mechanical trainee at Qatar Petroleum and also at Qatar Petrochemical Company as mechanical technician subsequently. The diploma in mechanical engineering which I acquired from Bradford College enabled me to get a promotion. The position is from mechanical technician to mechanical specialist as I was now able fully to understand the technicality of the rotating section in the company. The enhancement was further made by attaining a position in bagging and logistic area after attaining a degree in mechanical engineering from North Umbria University for two years. It is my inclination to gain more skills and hopefully secure high rank in my employment in the oil industry by completing the degree course in mechanical engineering which I had already started. The reason to this is that the course provides more relevance in the whole process in the oil industry from rotational section to logistics

The Endless Recovery Essay Example for Free

The Endless Recovery Essay 559 Testing Your Comprehension 1.Fossil fuels are abundant on our planet today and can be used to create many sources of energy which is why they are so prevalent. They are considered nonrenewable sources of energy because they take millions of years to form and because humans are rapidly depleting our fossil fuels faster then they can be created, which makes these fuels nonrenewable. 2.Fossil fuels were formed from the tissues of organisms that lived 100-500 million years ago. The energy these fuels contain came originally from the sun and was converted to chemical-bond energy as a result of photosynthesis. Environmental conditions determine what type of fossil fuel is formed because of the chemical composition of the starting material, the temperatures and pressures to which the material is subjects, the presence or absence of anaerobic decomposers, and the passage of time. Fossil fuels are often concentrated in localized deposits because some regions have substantial reserves of fossil fuels whereas others have very few. 3.Net energy expresses the difference between energy returned and energy invested. EROI is the ratio determined by dividing the quantity of energy returned from a process by the quantity pf energy invested in the process. These are important when evaluating energy sources because these ratios are always changing. 4.Coal is combusted and converted to water which turns to steam, this starts a turbine; this is how coal generates electricity. 5.Geologists have estimated the total amount of oil beneath the Arctic National Wildlife Refuge 1002 Area by drilling cores and conducting ground, air, and seismic surveys to map underground rock formations. This amount differs from the â€Å"technically recoverable† and â€Å"economically recoverable† because the â€Å"technically recoverable† ranges from 4.3-11.8 billion barrels, while the estimated amount ranges from 11.6-31.5 billion barrels. 6.We create petroleum products by refining hydrocarbon molecules that are separated into different size classes and are chemically transformed to create specialized f uels for heating, cooking and transportation, and to create lubricating oils, asphalts, and the production of plastics and other petroleum products. 7.Peak oil is when the rate of production of oil comes to its peak and begins to decline. Many experts believe we will soon pass the global production peak for oil because we are using it at a faster pace and are not finding new concentrations of oil. If we do not shift to  renewable energy sources, our society will meet its demise because we will run out of fossil fuels. 8.Fossil fuel production and consumption drive climate change, they pollute water as well as air, and they devastate natural systems. Drilling for oil in the Arctic National Wildlife Refuge would impact life in that area tremendously because that area would be quickly polluted and the wildlife would pay the price. Scientists are not even sure if this area has enough oil worth drilling for which is why it should not be touched. 9.An example of clean coal technology would be to use dry coal with high water contents. This approach would make is a cleaner-burning. Carbon capture technologies intend to remove carbon dioxide from power plants or other emissions, while carbon storage technologies try to sequester, or store, carbon dioxide from industrial emissions (underground under pressure in locations where it will not seep out). Both carbon capture and storage are in an effort to mitigate global climate change. 10.10. Two main approaches to energy conservation: as individuals, we can make conscious choices to reduce our own energy consumption by driving less, turning off lights when rooms are not being used, dialing down thermostats and cutting back on the use of energy-intensive machines and appliances. As a society we can conserve energy by making our energy consuming devices and processes more efficient. Consumers need to purchase energy efficiency appliances. Pg 587 Testing your comprehension 1. Of our global energy they contribute: Nuclear 20.9 %; Hydro 2.2%; Bio 9.8%. Of our global electricity they generate: Nuclear 13.8%; Hydro 15.6%; Bio 2.6%. 2. Nuclear fission occurs when the nuclei of large, heavy atoms, such as uranium or plutonium, are bombarded with neutrons. Neutrons tend to move too quickly for their nuclei to split when they collide, so the neutrons need to be slowed down. Each split nucleus emits energy in the form of heat, light and radiation. It also releases multiple neutrons. These neutrons, bombard other nearby uranium-235 atoms, which result in a self sustaining chain reaction. Engineers control fission in nuclear reactors by using control rods, which absorb neutrons. They are placed into the reactor among the water-bathed fuel rods. The engineers move these rods into and out of the water to maintain the fission reaction at the desired rate. 3. In  terms of greenhouse gas emission, nuclear, compared to coal, oil and natural gas, has less to none greenhouse emission. Hydropower and bioenergy compare 4. The incident at the Three Mile Island differed from that at Chernobyl because the Three Mile Island emergency was brought under control within days and the reactor was shut down quickly. This was due to a combination of mechanical failure and human error. The residents of the area were not as affected by the meltdown as those in Chernobyl. Chernobyl occurred because engineers had turned off safety systems to conduct tests, human error, and the unsafe reactor design caused an explosion. Many people were exposed to radiation; residents of the area were highly affected and till this day are still severely ill due to exposure. The accident killed 31 people. Radioactive fallout reached most of the Northern Hemisphere. 5. Some concerns about the disposal of radioactive waste are that if it’s dumped in the ocean it poses threat to fisheries, people and marine systems. If it’s kept in the power plants, the power plants are running out of space to hold the waste. If it is sent to Yucca Mountain, while being transported there can be an accident that exposes people to the radioactive waste. As of now the waste is being kept in storage areas within the nuclear power plant. The United States chose Yucca Mountain as a place to dump the nuclear waste but so far the project has not taken place. The waste will remain in their current locations. 6. Sources for bioenergy include the waste products of existing industries or processes, residue from agricultural crops, animal waste and organic waste. Bioenergy use differs between developed and developing nations because 7. The two primary biofules are ethanol and biodiesel. Ethanol is the alcohol in beer, wine and liquor. It is produced by fermenting biomass. In fermentation, carbohydrates are converted to sugar and then to ethanol. Gasoline engines run with gasoline blended with 10% of ethanol. Biodiesel , a fuel produced from vegetable oil, used cooking grease or animal fat. It is also used in vehicles and can be mixed with conventional petrodiesel. In North America and in Europe, cars are being filled with biodiesel and some buses and recycling trucks as well. 8. Bioenergy is from carbon neutral which releases no net carbon into the atmosphereif bioenergy replaced the use of fossilfuels we could help mitigate the problems of climate change. Burning bioenergy is not carbon neutral for the fact that plants need to be cut down in order to plant  bioenergy plants. 9. Storage type of hydroelectricity this type is the most widely used. It holds water back behind concrete dams that block the flow of water and just letting it flow out in smaller amounts through pipes that feed into a turbine. B. The other type of hydroelectricity generating plant is by implementing run-of-river approach.it generates electricity without greatly disrupting the flow of the river. Although it is not as damaging as damming the river, it doesn’t guarantee the same amount of water flow as by damming does. 10. two advantages with hydroelectric power are that the energy source is renewable and no carbon is emitted in the production of energy from this source. B. T wo negative impacts of hydroelectricity is that the area behind dams are flooded destroying habitat and the areas below dams are usually starved of water. The other negative is the thermal pollution. Areas behind the dam gat colder that natural and the areas in front of the dam become warmer than natural. Pg 614 Testing your comprehension 1.About 13% of our world’s energy is renewable and new renewable counts for 1%. The most prevalent form of renewable energy we use is biomass which accounts for 50% and hydroelectric which accounts for 35%. The form of energy most used to generate electricity is hydro power. 2.The diminishing amounts of fossil fuels have people concerned about our energy future. This is causing people to look for new renewable resources of energy. Solar and wind power are the new renewables that are experiencing the most rapid growth. 3.Passive solar heating is in the design of a building. It involves the installation of low south facing windows to capture sun, over hangs to shade windows in the summer, and the use of construction materials that capture the suns heat and release it throughout the day. Active solar heating is the use of technologies to heat water and air in structures. It involves installing flat-plate solar collectors on rooftops. Water, air or antifreeze passes through the panel and gets heated by the sun which in-turns transfers its heat to the building or to water tanks. 4.The photoelectric effect is when light reaches the PV cell and strikes one of a pair which is made of the semiconductor silicone. The light causes one plate to release electrons which are attracted by electrostatic forces to the opposing plate. Photovoltaic cells work when you attach wires to the plates  and allow the electrons to pass from one plate to the other freely. This causes an electric current or DC current which then can be converted to AC currents used in home and businesses. 5.Environmental and economic advantages of solar power are that the PV cells use no fuel, are quiet and safe, contain no moving parts, require little maintenance, and do not require a

Technology and Technological Advances Shape the American Culture :: Exploratory Essays Research Papers

Technological Advances Shape the American Culture People stay current with events that are happening worldwide in many ways. They watch the news on televisions, read the newspaper or go to news station's web sites. Looking back on the good old days, before television, cellular phones, and the Internet, life was simple. It is unbelievable how the little advances in technology since the late 1800s have shaped American culture. I remember 1948 well. This is when cable television had fifty stations across the country and one million receivers. From here the television industry grew to new heights. By 1951, Americans all over the country could watch the same thing. I recall CBS's attempt at broadcasting shows in color. This idea did not last long due to the use of technology mismatching with what was used in black and white television sets. One late evening in 1953, I saw on the news that the Federal Communications Commission (FCC) approved the RCA compatibility system that made color and black and white kosher. The addition of color gav e a new meaning to television. Later in 1953, the first educational television (ETV) station aired. Being just a kid at this time, educational shows did not fascinate me, but my mother made me watch them. Despite attempts to ignore what was being said, I learned more than I could imagine. Around 1956, the first motion pictures were produced in Hollywood and sent out around the country. I remember watching this exclusive event on the family television. My parents did not understand the thrill of movies coming out. I guess it was because they were too old fashioned. The television stations that we watch today became national cable stations in the 1970s. I remember 1975 as if it was yesterday. During this year the HBO station became the first national cable network. Back then, HBO watchers did not pay extra for the movies or shows they watched. Now if you want to watch a movie on HBO you pay extra on your cable bill, that is, if your cable company provides HBO. Another cable network that went national during the late 1970s was TBS. The TBS superstation was one of my favorite stations during that time. The shows broadcasted have gotten better and the movies have gotten more interesting. Television channel selections were rare during the 70s, but then the 80s came and with this decade came others. Technology and Technological Advances Shape the American Culture :: Exploratory Essays Research Papers Technological Advances Shape the American Culture People stay current with events that are happening worldwide in many ways. They watch the news on televisions, read the newspaper or go to news station's web sites. Looking back on the good old days, before television, cellular phones, and the Internet, life was simple. It is unbelievable how the little advances in technology since the late 1800s have shaped American culture. I remember 1948 well. This is when cable television had fifty stations across the country and one million receivers. From here the television industry grew to new heights. By 1951, Americans all over the country could watch the same thing. I recall CBS's attempt at broadcasting shows in color. This idea did not last long due to the use of technology mismatching with what was used in black and white television sets. One late evening in 1953, I saw on the news that the Federal Communications Commission (FCC) approved the RCA compatibility system that made color and black and white kosher. The addition of color gav e a new meaning to television. Later in 1953, the first educational television (ETV) station aired. Being just a kid at this time, educational shows did not fascinate me, but my mother made me watch them. Despite attempts to ignore what was being said, I learned more than I could imagine. Around 1956, the first motion pictures were produced in Hollywood and sent out around the country. I remember watching this exclusive event on the family television. My parents did not understand the thrill of movies coming out. I guess it was because they were too old fashioned. The television stations that we watch today became national cable stations in the 1970s. I remember 1975 as if it was yesterday. During this year the HBO station became the first national cable network. Back then, HBO watchers did not pay extra for the movies or shows they watched. Now if you want to watch a movie on HBO you pay extra on your cable bill, that is, if your cable company provides HBO. Another cable network that went national during the late 1970s was TBS. The TBS superstation was one of my favorite stations during that time. The shows broadcasted have gotten better and the movies have gotten more interesting. Television channel selections were rare during the 70s, but then the 80s came and with this decade came others.

Dehydrogenase in yeast Essay

During respiration, hydrogen atoms are removed from glucose molecules by enzymes called dehydrogenases and passed to various chemicals called hydrogen acceptors. As the hydrogen atoms pass from one hydrogen acceptor to another, energy is made available for chemical reactions in the cell. In this way, substances such as glucose provide energy for vital reactions in living organisms. In this experiment, a dye called methylene blue acts as an artificial hydrogen acceptor. When this dye is reduced by accepting hydrogen atoms it goes colourless. (a) Place about 30 mm of yeast suspension in a test-tube and, using a test-tube holder, heat this suspension over a small Bunsen flame until the liquid boils for about half a minute. Then cool the tube under the tap. (b) Label three test-tubes 1-3. (c) Using a graduated pipette or syringe, place 2 cm3 of the boiled yeast suspension in tube 1. (d) Using the graduated pipette or syringe, draw up 4 cm3 unboiled yeast suspension and place 2 cm3 in tube 2 and 2 cm3 in tube 3. (e) Rinse the pipette or syringe and use it to place 2 cm3 distilled water in tubes 1 and 2. (f) With the pipette or syringe, place 2 cm3 1 % glucose solution in tube 3. (g) Prepare a water bath by mixing hot and cold water from the tap to obtain a temperature between 35 and 45  °C. Place all three tubes in this water bath. Rinse the pipette or syringe. (h) Copy the table given below into your notebook. (i) After 5 minutes draw up 6 cm3 methylene blue solution in the pipette or syringe and place 2 cm3 in each tube. Shake all three tubes thoroughly and return them to the water bath, noting the time as you do so. Do not shake the tubes again. (j) Watch the tubes to see how long it takes for the blue colour to disappear, leaving the creamy colour of the yeast. A thin film of blue colour at the surface of the tube may be ignored but the tubes should not be moved. Record the times in your table. (k) The experiment may be repeated by simply shaking all the tubes again until the blue colour returns. |Tube |Contents |Time for methylene blue to go colourless Experiment 14. Discussion 1 Why was distilled water added to tubes 1 and 2? 2 What causes the methylene blue solution to go colourless (according to the introduction on p. 14.01)? 3 How do you explain the results with tube 1? 4 In which of tubes 2 and 3 was the methylene blue decolourized more rapidly? How can this result be explained? 5 If the hydrogen atoms for the reduction of methylene blue come from  glucose, why should the methylene blue in tube 2 become decolourized at all? 6 What do you think would be the effect of increasing the glucose concentration in tube 3? Explain your answer. 7 How could you extend the experiment to see if enzymes in yeast are capable of reducing methylene blue? 8 Why, do you think, the colour retuned on shaking the tubes? Experiment 14. Dehydrogenase in yeast – preparation Outline Methylene blue, acting as a hydrogen acceptor, is decolourized during the respiration of yeast. Addition of small amounts of substrate increases the rate of decolourization. Prior knowledge An elementary idea of respiration as a process which releases energy during the breaking down of carbohydrates; yeast is a microscopic living organism. Advance preparation and materials-per group 20% yeast suspension* 0.005% methylene blue solution+ (prepared 1~2 days ahead) 10 cm3 1 % glucose solution distilled water 10 cm3 Apparatus-per group test-tube rack and 4 test-tubes Bunsen burner 3 labels or spirit marker graduated pipette or syringe 5-10cm3 test-tube holder beaker or jar, for water to rinse pipette or syringe -per class clock Result The methylene blue: in tubes 2 and 3 should be decolourized in a few minutes with tube 3 changing first. * Add 40 g dried yeast and 0.4 g potassium dihydrogen phosphate (KH2PO4) to 200 cm3 distilled water in a tall 600 cm3 (or larger) beaker (a large jam jar will do). Cover the mouth of the container with aluminium foil and bubble air through the yeast suspension for one or two days using an aquarium aerator. Observe the suspension from time to time during the first two hours and control the air flow to prevent the yeast suspension frothing out of the jar. +Dissolve 0.05 g in 1 litre of distilled water. Methylene blue stains skin and clothing. Lab coats should be worn Experiment 14. Discussion – answers 1 The addition of distilled water to tubes 1 and 2 keeps the concentration of yeast and methylene blue the same in all three tubes. 2 The methylene blue accepts hydrogen atoms removed from glucose molecules during respiration. The reduced form of methylene blue is colourless. 3 Boiling will have killed the yeast. Dead yeast is therefore incapable of carrying out one or more stages in the transfer of hydrogen from glucose to methylene blue. (A similar answer may be given in terms of enzymes.) 4 Tube 3 will probably lose its blue colour first. Presumably if the hydrogen atoms for reducing methylene blue come from glucose, additional glucose will mean that more hydrogen atoms are available and decolourization will be more rapid. 5 Respiration will continue in yeast cells, using their own carbohydrate reserves such as glycogen. 6 It might be expected that increasing the glucose concentration would increase the rate of decolourization up to the point where all the available enzyme or enzymes were being used, or where the concentration of glucose was sufficient to plasmolyse the yeast cells. 7 If enzymes (dehydrogenases) are involved, it should be possible to extract them from yeast by grinding some dried yeast with sand and distilled water, and filtering. This could be the subject of further experiment, particularly if little or none of the carbohydrate reserve in yeast comes through in the filtrate. 8 Shaking the tubes introduces more oxygen which re-oxidises the methylene blue

Marginal cost Essay

1 Monopoly Why Monopolies Arise? Monopoly is a rm that is the sole seller of a product without close substitutes. The fundamental cause of monopoly is barriers to entry: A monopoly remains the only seller in its market because other rms cannot enter the market and compete with it. Barriers to entry have three main sources: 1. Monopoly Resources. A key resource is owned by a single rm. Example: The DeBeers Diamond Monopoly|this rm controls about 80 percent of the diamonds in the world. 2. Government-Created Monopolies. Monopolies can arise because the government grants one person or one rm the exclusive right to sell some good or service. Patents are issued by the government to give rms the exclusive right to produce a product for 20 years. 3. Natural Monopoly: a monopoly that arises because a single rm can supply a good or service to an entire market at a smaller cost than could two or more rms. A natural monopoly occurs when there are economies of scale, implying that average total cost falls as the rm’s scale becomes larger. Monopoly versus Competition The key di erence between a competitive rm and a monopoly is the monopoly’s ability to control price. The demand curves that each of these types of rms faces is di erent as well. 1. A competitive rm faces a perfectly elastic demand at the market price. The rm can sell all that it wants to at this price. 2. A monopoly faces the market demand curve because it is the only seller in the market. If a monopoly wants to sell more output, it must lower the price of its product. A monopoly’s marginal revenue will always be less than the price of the good (other than at the rst unit sold). 1. If the monopolist sells one more unit, his total revenue (P Q) will rise because Q is getting larger. This is called the output e ect. 2. If the monopolist sells one more unit, he must lower price. This means that his total revenue (P Q) will fall because P is getting smaller. This is called the price e ect. Remember that demand tends to be elastic along the upper lefthand portion of the demand curve. Thus, a decrease in price causes total revenue to increase. Further down the demand curve, the demand is inelastic. In this region, a decrease in price results in a drop in total revenue (implying that marginal revenue is now less than zero). Pro t Maximization The monopolist’s pro t-maximizing quantity of output occurs where marginal revenue is equal to marginal cost. 1. If the rm’s marginal revenue is greater than marginal cost, pro t can be increased by raising the level of output. 2. If the rm’s marginal revenue is less than marginal cost, pro t can be increased by lowering the level of output. Even though MR = MC is the pro t-maximizing rule for both competitive rms and monopolies, there is one important di erence. 1. In competitive rms, P = MR at the pro t-maximizing level of output, P = MC . 2. In a monopoly, P > MR at the pro t maximizing level of output, P > MC . The monopolist’s price is determined by the demand curve (which shows us the willingness to pay of consumers). Question: Why a Monopoly Does Not Have a Supply Curve? 1. A supply curve tells us the quantity that a rm chooses to supply at any given price. 2. But a monopoly rm is a price maker the rm sets the price at the same time it chooses the quantity to supply. 3. The market demand curve tells us how much the monopolist will supply. A Monopoly’s Pro t Pro t = TR ; TC : Also, TR TC Pro t = ; Q Q or Pro t = (P ; ATC ) Q Q: The Welfare Cost of Monopoly The socially e cient quantity of output is found where the demand curve and the marginal cost curve intersect. This is where total surplus is maximized. Because the monopolist sets marginal revenue equal to marginal cost to determine its output level, it will produce less than the socially e cient quantity of output. Public Policies Toward Monopolies 1. Increasing Competition with Antitrust Laws. Antitrust laws are a collection of statutes that give the government the authority to control markets and promote competition. Antitrust laws allow the government to prevent mergers and break up large, dominating companies. (a) The Sherman Antitrust Act was passed in 1890 to lower the market power of the large and powerful rusts† that were viewed as dominating the economy at that time. (b) The Clayton Act was passed in 1914 it strengthened the government’s ability to curb monopoly power and authorized private lawsuits. 2. Regulation. Regulation is often used when the government is dealing with a natural monopoly. Most often, regulation involves government limits on the price of the product. While we might believe that the government can eliminate the deadweight loss from monopoly by setting the monopolist’s price equal to its marginal cost, this is often di cult to do. (a) If the rm is a natural monopoly, its average total cost curve will be declining because of its economies of scale. (b) When average total cost is falling, marginal cost must be lower than average total cost. (c) Therefore, if the government sets price equal to marginal cost, the price will be below average total cost and the rm will earn a loss, causing the rm to eventually leave the market. (d) Therefore, governments may choose to set the price of the monopolist’s product equal to its average total cost. This gives the monopoly zero pro t, but assures that it will remain in the market. Note that there is still a deadweight loss in this situation because the level of output will be lower than the socially e cient level of output. 3. Public Ownership. Rather than regulating a monopoly run by a private rm, the government can run the monopoly itself. However, economists generally prefer private ownership of natural monopolies than public ownership. 4. Do Nothing. Sometimes the costs of government regulation outweigh the bene ts. Therefore, some economists believe that it is best for the government to leave monopolies alone. Question: Should the government break up Microsoft? Price Discrimination Price discrimination is the business practice of selling the same good at di erent prices to di erent customers. Perfect price discrimination describes a situation where a monopolist knows exactly the willingness to pay of each customer and can charge each customer a di erent price. Without price discrimination, a rm produces an output level that is lower than the socially e cient level. If a rm perfectly price discriminates, each customer who values the good at more than its marginal cost will purchase the good and be charged his or her willingness to pay. 1. There is no deadweight loss in this situation. 2. Because consumers pay a price exactly equal to their willingness to pay, all surplus in this market will be producer surplus. Examples of Price Discrimination: 1. Movie Tickets 2. Airline Prices 3. Discount Coupons 4. Financial Aid 5. Quantity Discounts.

Economic Forces and Stock Market

Economic Forces and Stock Market Free Online Research Papers Chen, Nai-Fu, Roll, Richard and Stephen A. Ross. â€Å"Economic Forces and the Stock Market.† The Journal of Business 59, 3 (1986): pp.383-403. Chen, Roll and Ross (1986) were among the earliest researchers to identify and test economics factors that should affect stock returns either through future cash flows or through the discount rate. By analyzing factors such as inflation, the term structure of interest rates, industrial production etc. and discovered them to be important in explaining stock returns. Simply stated, Chen et al. strove to discover, the relation of stock price and macroeconomic variables. In 1986 Chen et al. observed and experimented the influence of economic state variables on the stock prices. By experimenting with the US economic data they established that the economic state variables work as discount rate and affect the future dividends, which in turn influence the stock prices. APT factors of Chen, et al. include: Growth in Industrial Production (MP), Changes in expected inflation (DEI), Unexpected Inflation (UI), Unexpected changes in risk premiums (URP), Unexpected changes in term structure slope (UTS). The macroeconomic variables are the foundation of APT model. According to the findings of the paper, effect of these variables on the equity return is as follow: Inflation: Inflation influences the Discount rate and future cash flows. Chen, Roll and Ross (1986) showed negative relation between inflation and stock market. Risk Premium: In order to know the markets reaction to risk, return on safe bonds and risky bonds are used. The term structure of interest rates: the relation of stock prices with long-term interest rate is negative. The short-term interest rate may or may not have negative influence on stock prices. Stock returns were more negative in periods when industrial production fell, and the default spread, unanticipated inflation occurred and the actual rate of return witnessed an increase. Stocks did considerably better in periods when the yield curve was more upward sloping, long term rates were elevated than short-term rates. Persistence in Mutual Fund Performance Carhart, Mark M. â€Å"On Persistence in Mutual Fund Performance.† The Journal of Finance 52, 1 (1997): pp.57-82. Carhart observed the persistence in mutual fund performance by using a sample of equity fund. He took a total of 1,892 funds as a sample of equity from 1963-1993. He divided the sample in three categories, aggressive growth, long-term growth, and growth-and income. Carhart utilized Capital Asset Pricing Model (CAPM) and Four Factor Model (FFM) for performance measurement. Carhart explains that Funds portfolios are ranked on lagged one-year returns to estimate the performance. The fund portfolios are equally weighted; when the fund disappears, the rate is readjusted. With the CAMP model on the decile portfolios the post-formation monthly excess returns decreases monotonically in rank and shows annualized spread of 8 percent while in four-factor model, size and momentum accounts for the spread among portfolios. It was found that expense ratios, portfolio turnover, and load fees are negatively related to performance. The performance is reduced one-for-one by expense rations and turnover reduces performance about 95 basis points for every transaction. The load fund consistently and substantially underperforms no-load funds. In addition, the funds with high past alpha performs high alphas and higher expected returns. The funds on top-decile earn back investment cost but the bottom-decile funds underperforms about twice there investment cost. At last, Carhart suggests mutual fund investors that funds, which constantly performed poor, are not be consider, the funds which show high return last year, will show expected returns next year higher than average and performance have a negative impact by investment cost, transaction cost and load fees. Research Papers on Economic Forces and Stock MarketIncorporating Risk and Uncertainty Factor in CapitalLifes What IfsResearch Process Part OneRiordan Manufacturing Production PlanInfluences of Socio-Economic Status of Married MalesTwilight of the UAWDefinition of Export QuotasBionic Assembly System: A New Concept of SelfEffects of Television Violence on ChildrenThe Project Managment Office System

The Domestication and History of Modern Horses

The Domestication and History of Modern Horses The modern domesticated horse (Equus caballus) is today spread throughout the world and among the most diverse creatures on the planet. In North America, the horse was part of the megafaunal extinctions at the end of the Pleistocene. Two wild subspecies survived until recently, the Tarpan (Equus ferus ferus, died out ca 1919) and Przewalskis Horse (Equus ferus przewalskii, of which there are a few left). Horse history, especially the timing of the domestication of the horse, is still being debated, partly because the evidence for domestication itself is debatable. Unlike other animals, criteria such as changes in body morphology (horses are extremely diverse) or the location of a particular horse outside of its normal range (horses are very widespread) are not useful in helping resolve the question. Evidence for Horse Domestication The earliest possible hints for domestication would be the presence of what appears to be a set of postmolds with lots of animal dung within the area defined by the posts, which scholars interpret as representing a horse pen. That evidence has been found at Krasnyi Yar in Kazakhstan, in portions of the site dating to as early as 3600 BC. The horses may have been kept for food and milk, rather than riding or load-bearing. Accepted archaeological evidence of horseback riding includes bit wear on horse teeth- that has been found in the steppes east of the Ural mountains at Botai and Kozhai 1 in modern Kazakhstan, around 3500-3000 BC. The bit wear was only found on a few of the teeth in the archaeological assemblages, which might suggest that a few horses were ridden to hunt and collect wild horses for food and milk consumption. Finally, the earliest direct evidence of the use of horses as beasts of burden- in the form of drawings of horse-drawn chariots- is from Mesopotamia, about 2000 BC. Krasnyi Yar includes over 50 residential pithouses, adjacent to which have been found dozens of postmolds. The postmolds- archaeological remnants of where posts have been set in the past- are arranged in circles, and these are interpreted as evidence of horse corrals. Horse History and Genetics Genetic data, interestingly enough, has traced all extant domesticated horses to one founder stallion, or to closely related male horses with the same Y haplotype. At the same time, there is a high matrilineal diversity in both domestic and wild horses. At least 77 wild mares would be required to explain the diversity of the mitochondrial DNA (mtDNA) in current horse populations, which probably means quite a few more. A 2012 study (Warmuth and colleagues) combining archaeology, mitochondrial DNA, and Y-chromosomal DNA supports the domestication of horse as occurring once, in the western part of the Eurasian steppe, and that because of the horses wild natures, several repeated introgression events (restocking of horse populations by adding wild mares), must have occurred. As identified in earlier studies, that would explain the diversity of mtDNA. Three Strands of Evidence for Domesticated Horses In a paper published in Science in 2009, Alan K. Outram and colleagues looked at three strands of evidence supporting horse domestication at Botai culture sites: shin bones, milk consumption, and bitwear. These data support domestication of the horse between about 3500-3000 BC sites in what is today Kazakhstan. Horses skeletons at Botai Culture sites have gracile metacarpals. The horses metacarpals- the shins or cannon bones- are used as key indicators of domesticity. For whatever reason (and I wont speculate here), shins on domestic horses are thinner- more gracile- than those of wild horses. Outram et al. describe the shinbones from Botai as being closer in size and shape to those of Bronze age (fully domesticated) horses compared to wild horses. Fatty lipids of horse milk were found inside of pots. Although today it seems a bit weird to westerners, horses were kept for both their meat and milk in the past- and still are in the Kazakh region as you can see from the photograph above. Evidence of horse milk was found at Botai in the form of fatty lipid residues on the insides of ceramic vessels; further, evidence for consumption of horse meat has been identified at Botai culture horse and rider burials. Bit wear is in evidence on horse teeth. Researchers noted bitting wear on horses teeth- a vertical strip of wear on the outside of horses premolars, where the metal bit damages the enamel when it sits between the cheek and tooth. Recent studies (Bendrey) using scanning electron microscopy with energy dispersive X-ray microanalysis found microscopic-sized fragments of iron embedded on Iron Age horse teeth, resulting from metal bit use. White Horses and History White horses have had a special place in ancient history-according to Herodotus, they were held as sacred animals in the Achaemenid court of Xerxes the Great (ruled 485-465 BC). White horses are associated with the Pegasus myth, the unicorn in the Babylonian myth of Gilgamesh, Arabian horses, Lipizzaner stallions, Shetland ponies, and Icelandic pony populations. The Thoroughbred Gene A recent DNA study (Bower et al.) examined the DNA of Thoroughbred racing horses and identified the specific allele which drives their speed and precocity. Thoroughbreds are a specific breed of horse, all of whom today are descended from the children of one of three foundation stallions: Byerley Turk (imported to England in the 1680s), Darley Arabian (1704) and Godolphin Arabian (1729). These stallions are all of Arab, Barb and Turk origin; their descendants are from one of only 74 British and imported mares. Horse breeding histories for Thoroughbreds have been recorded in the General Stud Book since 1791, and the genetic data certainly supports that history. Horse races in the 17th and 18th centuries ran 3,200-6,400 meters (2-4 miles), and horses were usually five or six years old. By the early 1800s, the Thoroughbred was bred for traits that enabled speed and stamina over distances from 1,600-2,800 meters at three years of age; since the 1860s, the horses have been bred for shorter races (1,000-1400 meters) and younger maturity, at 2 years. The genetic study looked at the DNA from hundreds of horses and identified the gene as C type myostatin gene variant, and came to the conclusion that this gene originated from a single mare, bred to one of the three founder male horses about 300 years ago. See Bower et al for additional information. Thistle Creek DNA and Deep Evolution In 2013, researchers led by Ludovic Orlando and Eske Willerslev of the Centre for GeoGenetics, Natural History Museum of Denmark and University of Copenhagen (and reported in Orlando et al. 2013) reported on a metapodial horse fossil which had been found in permafrost within a Middle Pleistocene context in the Yukon territory of Canada and dated between 560,00-780,000 years ago. Amazingly, the researchers found that there were sufficiently intact molecules of collagen within the matrix of the bone to enable them to map the Thistle Creek horses genome. The researchers then compared the Thistle Creek specimen DNA to that of an Upper Paleolithic horse, a modern donkey, five modern domestic horse breeds, and one modern Przewalskis horse. Orlando and Willerslevs team found that over the past 500,000 years, horse populations have been enormously sensitive to climate change and that extremely low population sizes are associated with warming events. Further, using the Thistle Creek DNA as a baseline, they were able to determine that all modern existing equids (donkeys, horses, and zebras) originated from a common ancestor some 4-4.5 million years ago. In addition, Przewalskis horse diverged from the breeds which became domestic some 38,000-72,000 years ago, confirming the long-held belief that Przewalskis is the last remaining wild horse species. Sources Bendrey R. 2012. From wild horses to domestic horses: a European perspective. World Archaeology 44(1):135-157. Bendrey R. 2011. Identification of metal residues associated with bit-use on prehistoric horse teeth by scanning electron microscopy with energy dispersive X-ray microanalysis. Journal of Archaeological Science 38(11):2989-2994. Bower MA, McGivney BA, Campana MG, Gu J, Andersson LS, Barrett E, Davis CR, Mikko S, Stock F, Voronkova V et al. 2012. The genetic origin and history of speed in the Thoroughbred racehorse. Nature Communications 3(643):1-8. Brown D, and Anthony D. 1998. Bit Wear, Horseback Riding and the Botai Site in Kazakstan. Journal of Archaeological Science 25(4):331-347. Cassidy R. 2009. The horse, the Kyrgyz horse and the ‘Kyrgyz horse’. Anthropology Today 25(1):12-15. Jansen T, Forster P, Levine MA, Oelke H, Hurles M, Renfrew C, Weber J, Olek, and Klaus. 2002. Mitochondrial DNA and the origins of the domestic horse. Proceedings of the National Academy of Sciences 99(16):10905–10910. Levine MA. 1999. Botai and the origins of horse domestication. Journal of Anthropological Archaeology 18(1):29-78. Ludwig A, Pruvost M, Reissmann M, Benecke N, Brockmann GA, Castaà ±os P, Cieslak M, Lippold S, Llorente L, Malaspinas A-S et al. 2009. Coat Color Variation at the Beginning of Horse Domestication. Science 324:485. Kavar T, and Dovc P. 2008. Domestication of the horse: Genetic relationships between domestic and wild horses. Livestock Science 116(1):1-14. Orlando L, Ginolhac A, Zhang G, Froese D, Albrechtsen A, Stiller M, Schubert M, Cappellini E, Petersen B, Moltke I et al. 2013. Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse. Nature in press. Outram AK, Stear NA, Bendrey R, Olsen S, Kasparov A, Zaibert V, Thorpe N, and Evershed RP. 2009. The Earliest Horse Harnessing and Milking. Science 323:1332-1335. Outram AK, Stear NA, Kasparov A, Usmanova E, Varfolomeev V, and Evershed RP. 2011. Horses for the dead: funerary foodways in Bronze Age Kazakhstan. Antiquity 85(327):116-128. Sommer RS, Benecke N, Là µugas L, Nelle O, and Schmà ¶lcke U. 2011. Holocene survival of the wild horse in Europe: a matter of open landscape? Journal of Quaternary Science 26(8):805-812. Rosengren Pielberg G, Golovko A, Sundstrà ¶m E, Curik I, Lennartsson J, Seltenhammer MH, Drum T, Binns M, Fitzsimmons C, Lindgren G et al. 2008. A cis-acting regulatory mutation causes premature hair graying and susceptibility to melanoma in the horse. Nature Genetics 40:1004-1009. Warmuth V, Eriksson A, Bower MA, Barker G, Barrett E, Hanks BK, Li S, Lomitashvili D, Ochir-Goryaeva M, Sizonov GV et al. 2012. Reconstructing the origin and spread of horse domestication in the Eurasian steppe. Proceedings of the National Academy of Sciences Early edition.

An artist from time Essay Example | Topics and Well Written Essays - 1500 words

An artist from time - Essay Example His major interest was human psychology, his portraits and self-portraits exhibiting his penetration of character. Rembrandt was the ninth and the most gifted child of a miller and a baker. After finishing a Latin school he was sent to the university. His inclination to painting made his parents give him in apprenticeship to the local painter Jacob Isaacszoon van Swaneneburg (1619-22). However, Rembrandt got his chief training during the six month (around 1923) of apprenticeship in the studio of Pieter Lastman, the Amsterdam leading painter of biblical, mythological, and historical pictures of that time. Here Rembrandt learnt to draw grand subjects in a broad format, paying careful attention to dramatic gestures, compositional grouping, the details of ancient costumes and setting. It was here that Rembrandt got acquainted with works of the major baroque artists, with their interest to light and shadow and human emotions. The baroque style was characterized with naturalistic illusionism, underlined by dramatic lighting effects, high sense of theatricality, movement of forms and energy. Baroque ar tists strove to make art close and clear to common people. Unlike the Renaissance art with its focus on reason, Baroque paintings represented emotions, capturing the most dramatic points of the action occurring (Heindorff 2006). Rembrandt learnt the art of gesture and light from Elsheimer, Caravaggio, van Honthorst and other representatives of the baroque style. At the age of 22 Rembrandt opened a studio in Leiden, and in 1627 started accepting students. Later in 1631 Rembrandt moved to Amsterdam, became a professional portraitist and had students, among whom were most of the future prominent artists of Holland. (Encyclopedia Britannica 2006; Heindorff 2006). Danae, the mythological painting of 1636, relates to the early Amsterdam period in Rembrandt’s career. It was the time when he emulated the baroque style of Rubens. As usual, Rembrandt denied the