Animal Senses Biology magnetoreception mechanism on Migratory Birds Essay

Animal Senses Biology magnetoreception mechanism on Migratory Birds - Essay Example Birds have various times of migration. Some birds migrate during the day like swallows and crows, while some migrate at night such as warblers, cuckoos, wild fowls and woodpeckers, as well as most songbirds (Engels 1). Stimuli such as internal body clocks or subtle weather changes cause these birds to migrate, and this ability can be explained by a phenomenon called magnetoreception, which is the ability of some organisms to detect the Earth’s magnetic field in perceiving direction, altitude or location (Solov'yov 40). The Earth’s magnetic field can be detected through various mechanisms such as chemical, electrical and mechanical means, and any of these stimuli can be converted into a molecular signal like a light-stimulated or photochemical reaction in the retina, which can then be recognized and perceived by magnetoceptive organisms like birds and insects (41). Hypotheses in the mechanisms of magnetoreception in birds There are various mechanisms hypothesized for mag netoreception to occur in birds, and one of these is the phenomenon involving a chemical compass where chemical reactions occur involving the transitions of electrons between high and low energy configurations or spin states, influenced by the Earth’s magnetic field (Rodgers 353). ... The amount of products from this reaction and the length of the half-life time of the radical base pair would depend on the strength of the detected magnetic field. The strength of the magnetic field determines the amount of radical base products and their length of half-life, and their linear relationship can be used to determine the strength of the magnetic field (Ritz 135; Rodgers 353). Thus, the stronger the magnetic field, the radical base pair mechanism would be producing more molecules with unpaired electrons, which in turn keeps the bird in its intended direction. These reactions occur in the photoreceptor region of the bird’s eye, helping the birds detect the strength of Earth’s magnetic field through radical base pair mechanism. The radical spinning is explained by hyperfine interactions, and these happen when there is a coupling between the magnetic moments of the unpaired electron and its atomic nucleus (Ritz 135). The interchanging conversions between the s inglet state and the triplet state is a process whose frequency is determined by the strength of the hyperfine reactions. This system is not only influenced by the intensity but also by the direction of the field, which makes it act like a compass (136). The tendency of one component of hyperfine reaction to be strong towards one direction only determines the interchanging conversion rate of the S and T state. Thus the effects of the magnetic field would be depending on the direction of the magnetic field with respect to the alignment of the radical pairs. These are the mechanisms by which birds are able to travel at night. Photoreceptor mechanisms in birds Birds have two types of light receptors in their eye: night vision

Sarbanes-Oxley Act Essay Example | Topics and Well Written Essays - 500 words

Sarbanes-Oxley Act - Essay Example Examples include WorldCom and Enron companies. According to section 404(a) of the Act, it is a requirement that managements of companies assess their Internal Controls effectiveness and report on the same over financial reporting. Also, Subsection (b) of the same section, calls on independent auditors to attest to the assessments done by the managements. This is regarding Internal Controls effectiveness. The opinion of the study is that it is not too much a regulation. As stipulated by the Securities and Exchange Commissions report, the enactment of section 404 of the Sarbox Act have proven too costly. The outlays are incredibly high to companies, which has led to some attempts at their reduction while upholding effectiveness like the reforms of year 2007. (sec.gov, 2009) However, the cost of implementation is far much less than the 2001-2002 business scandals cost. These are with the inclusion of Global Crossing, Tyco, WorldCom and Enron companies, which shook the confidence of investors a great deal. (Hallberg, 2008 p390) A case at hand to support the argument that, it is not too much regulation is that of the collapsed Enron Company. This is where, in October 2001, Enron company had made public their third quarter earnings report where they purported to have realized an after tax Earnings of USD 1.01 billion. On the same date of reporting, Enron had cut down equity of shareholders by USD 1.2 billion, which it claimed to be the rectification of accounting errors. In November, 2001 the company filed with the SEC Form 8-K, considering the current events. This form 8-K stipulated that Enron would like to restate their financial statements from year 1997 through 2001 June. These statements led to a shocking fall of income of USD 569 million. In the same year, 2001, Enron Company filed for bankruptcy which triggered investigations. (De Vay, 2006 p3) As said earlier, as stipulated by the Securities and Exchange