Reasoning animal

Give two reasons animals living in cold climates tend to form a thick layer of fat just prior to the onset of winter. 

In his early disputations Boerhaave defined the soul as the principle of life in man, as well as the beginning of thinking, conscience and wiU. The soul is a thinking entity and although it is closely connected to the body, it is distinct from the body. It is the principle which makes man a reasonable animal. Boerhaave seems to use the words soul (inimd) and mind i ens) arbitrarily. Yet, he must have had a clear understanding of a difference between the two. Soul... 

The study in monkeys involved lactalbumin or soybean protein-based diets. Nitrogen balance was attained with the feeding of relatively low levels of lactalbumin (0.15 g N/day) but relatively high levels of soy protein (0.30 g N/day). Another point is that lactalbumin supported a positive N balance at lower concentrations than did soy protein. These findings indicate that lactalbumin is a higher-quality protein than soy protein. The concept of protein quality is explored next. Lactalbumin is a higher-quality protein than soy protein, as the soy protein is somewhat deficient in methionine. For this reason, animal diets based on soybean protein are usually supplemented with methionine. 

Studies in rodents and nonhuman primates indicate that oral intake of high doses of manganese can lead to biochemical and behavioral changes indicative of nervous system effects (Bonilla and Prasad 1986 Chandra 1983 Gupta et al. 1980 Kristensson et al. 1986 Lai et al. 1984 Nachtman et al. 1986), and this is supported by intravenous studies in monkeys (Newland and Weiss 1992). Rodents do not appear to be as susceptible to manganese neurotoxicity as humans however, a study by Newland and Weiss (1992) indicates that Cebus monkeys would be a reasonable animal model. Further studies in animals may help determine the basis for the apparent differences in route and species susceptibility. 

The real-time interactive character of the system pushes the limit of network latency more than bandwidth. For example, a half second may be required for a send and reply in such cases involving geo-synchronous satellites, a factor of 5 too great for reasonable animation. The future may bring low-orbit satellite systems or undersea optical fibre, which with faster gateways, would suffice. 

The extrapolation of animal toxicological data to man is always tenuous, but for obvious reasons, animal test models are necessarily used. Unfortunately, there is no single animal model in which effects perfectly correlate with toxicity in children some slippage is bound to occur in comparisons between the results of animal and clinical or human studies. 

In the normal human diet, about 25% to 50% of the caloric intake consists of fats and oils. These substances are the most concentrated form of food energy in our diet. When metabolized, fats produce about 9.5 kcal of energy per gram. Carbohydrates and proteins produce less than half this amount. For this reason, animals tend to build up fat deposits as a reserve source of energy. They do this, of course, only when their food intake exceeds their energy requirements. In times of starvation, the body metabolizes these stored fats. Even so, some fats are required by animals for bodily insulation and as a protective sheath aroimd some vital organs. 

First, we consider the experimental aspects of osmometry. The semiperme-able membrane is the basis for an osmotic pressure experiment and is probably its most troublesome feature in practice. The membrane material must display the required selectivity in permeability-passing solvent and retaining solute-but a membrane that works for one system may not work for another. A wide variety of materials have been used as membranes, with cellophane, poly (vinyl alcohol), polyurethanes, and various animal membranes as typical examples. The membrane must be thin enough for the solvent to pass at a reasonable rate, yet sturdy enough to withstand the pressure difference which can be... 

Antibiotics (qv) have been fed at subtherapeutic levels to promote mminant animal growth. Possible reasons for the observed growth include decreased activity of microbes having a pathogenic effect on the animal, decreased production of microbial toxins, decreased microbial destmction of essential nutrients, increased vitamin synthesis or synthesis of other growth factors, and increased nutrient absorption because of a thinner intestinal wall... 

Eor this reason, finding the location of the genes that control production, as well as the alleles, ie, DNA sequences, for superior production, is a significant strategy for engineering improved animal species through biotechnology. 

The narcotic potency and solubiUty in oHve oil of several metabohcaHy inert gases are Hsted in Table 10. The narcotic potency, ED q, is expressed as the partial pressure of the gas in breathing mixtures requited to produce a certain degree of anesthesia in 50% of the test animals. The solubiUties are expressed as Bunsen coefficients, the volume of atmospheric pressure gas dissolved by an equal volume of Hquid. The Hpid solubiHty of xenon is about the same as that of nitrous oxide, a commonly used light anesthetic, and its narcotic potency is also about the same. As an anesthetic, xenon has the virtues of reasonable potency, nonflammability, chemical inertness, and easy elimination by the body, but its scarcity and great cost preclude its wide use for this purpose (see Anesthetics). 

Low temperature (It) tars of Eischer-Tropsch (ET) fractions provide reasonable substrates for growth of yeast for human or animal food supplements. Yeast growth yields were 99.8% (ET fraction), 95.2 and 84.2% (It tar) of those from a petroleum-derived paraffin fraction (63) (see Eoods, nonconventional). 

A comprehensive study of the tolerance of laboratory animals to vapors of 2-nitropropane was reported in 1952 (100). In a study pubHshed in 1979, rabbits and rats survived exposure to nitromethane for six months at 750 and 100 ppm, respectively, with no unexpected findings (101). Similarly, no compound-related effects were found for rabbits exposed to 2-nitropropane at 200 ppm or for rabbits or rats exposed at 27 ppm. Liver damage was extensive in male rats exposed at 207 ppm for six months, and hepatocellular carcinomas were observed. Subsequendy, the International Agency for Research on Cancer (lARC) found that there is "sufficient evidence" to conclude that 2-nitropropane causes cancer in rats but that epidemiologic data are inadequate to reinforce the conclusion in humans (102). The National Toxicology Program also concluded that it "may reasonably be anticipated to be a carcinogen" (103). 

For the above reasons, chronic exposure studies are frequently designed in such a way that it is possible to combine observations for tumorigenesis and noimeoplastic tissue injury. Chronic studies are usually extensively monitored. It is common practice to sacrifice animals at intervals during the study in order to detect the onset of any tissue injury. For two-year exposure studies, it is most meaningful to have interim sacrifices at 12 and 18 months. 

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