958 resultados para the Great Depression
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Both predators and parasites can elicit behavioral and physiological responses in prey and hosts, respectively. These responses may involve the reallocation of resources and may thus limit each other. We investigated the effects of concurrent pre-laying exposure of great tit females (Parus major) to both a simulated predation risk and a nest-based ectoparasite, the hen flea (Ceratophyllus gallinae), on nestling growth and development. We manipulated perceived predation risk using models and vocalizations of sparrowhawks (Accipiter nisus). At the start of incubation, we swapped whole clutches between treated and untreated nests to separate pre-laying maternal effects from posthatching effects. Since costs and benefits of maternal responses to parasites need to be assessed under parasite pressure, we infested half of the rearing nests with hen fleas. Parasites had negative effects on mass gain and wing growth, both via maternal effects and via direct exposure of nestlings, whereas maternal predation risk had no significant effect. The interaction between predator and parasite treatments was not significant and, thus, suggests the absence of a trade-off between the 2 stressors operating at the level of maternal effects. Alternatively, the complexity of the design, despite a relatively large sample size, may have limited the power for detection of this expected trade-off.
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by C. Duschinsky
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Joseph Herman Hertz
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BACKGROUND Intravenous fluids are commonly prescribed in childhood. 0.9 % saline is the most-used fluid in pediatrics as resuscitation or maintenance solution. Experimental studies and observations in adults suggest that 0.9 % saline is a poor candidate for fluid resuscitation. Although anesthesiologists, intensive care specialists, perioperative physicians and nephrologists have been the most active in this debate, this issue deserves some physiopathological considerations also among pediatricians. RESULTS As compared with so-called "balanced" salt crystalloids such as lactated Ringer, administration of large volumes of 0.9 % saline has been associated with following deleterious effects: tendency to hyperchloremic metabolic acidosis (called dilution acidosis); acute kidney injury with reduced urine output and salt retention; damaged vascular permeability and stiffness, increase in proinflammatory mediators; detrimental effect on coagulation with tendency to blood loss; detrimental gastrointestinal perfusion and function; possible uneasiness at the bedside resulting in unnecessary administration of more fluids. Nevertheless, there is no firm evidence that these adverse effects are clinically relevant. CONCLUSIONS Intravenous fluid therapy is a medicine like insulin, chemotherapy or antibiotics. Prescribing fluids should fit the child's history and condition, consider the right dose at the right rate as well as the electrolyte levels and other laboratory variables. It is unlikely that a single type of fluid will be suitable for all pediatric patients. "Balanced" salt crystalloids, although more expensive, should be preferred for volume resuscitation, maintenance and perioperatively. Lactated Ringer appears unsuitable for patients at risk for brain edema and for those with overt or latent chloride-deficiency. Finally, in pediatrics there is a need for new fluids to be developed on the basis of a better understanding of the physiology and to be tested in well-designed trials.
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This study examines the effect of the Great Moderation on the relationship between U.S. output growth and its volatility over the period 1947 to 2006. First, we consider the possible effects of structural change in the volatility process. In so doing, we employ GARCH-M and ARCH-M specifications of the process describing output growth rate and its volatility with and without a one-time structural break in volatility. Second, our data analyses and empirical results suggest no significant relationship between the output growth rate and its volatility, favoring the traditional wisdom of dichotomy in macroeconomics. Moreover, the evidence shows that the time-varying variance falls sharply or even disappears once we incorporate a one-time structural break in the unconditional variance of output starting 1982 or 1984. That is, the integrated GARCH effect proves spurious. Finally, a joint test of a trend change and a one-time shift in the volatility process finds that the one-time shift dominates.
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Regulatory change not seen since the Great Depression swept the U.S. banking industry beginning in the early 1980s and culminating with the Interstate Banking and Branching Efficiency Act of 1994. Banking analysts anticipated dramatic consolidation with large numbers of mergers and acquisitions. Less well documented, but equally important, was the continuing entry of new banks, tempering the decline in the overall number of banking institutions. This paper examines whether deregulation affected bank new-charter (birth), failure (death), and merger (marriage) rates during the 1980s and 1990s after controlling for bank performance and state economic activity. We find evidence that intrastate deregulation stimulated births and marriages, but not deaths. Moreover, we find little evidence that interstate deregulation affected births, deaths, or marriages, except that the marriage rate rose after the implementation of the Interstate Banking and Branching Efficiency Act. Finally, pair-wise temporal causality tests among births, deaths, and marriages show that mergers temporally lead new charters and that failures lead mergers (a demonstration effect).
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Regulatory change not seen since the Great Depression swept the U.S. banking industry beginning in the early 1980s and culminating with the Interstate Banking and Branching Efficiency Act of 1994. Banking analysts anticipated dramatic consolidation with large numbers of mergers and acquisitions. Less well documented, but equally important, was the continuing entry of new banks, tempering the decline in the overall number of banking institutions. This paper examines whether deregulation affected bank new-charter, failure, and merger rates during the 1980s and 1990s after controlling for bank performance and state economic activity. We find evidence that intrastate deregulation stimulated new charters and mergers, but not failures. Moreover, we find little evidence that interstate deregulation affected new charters, failures, or mergers.