144 research outputs found

    Morphological Variation in Cephalogonimus americanus (Trematoda: Cephalogonimidae) from Amphibians in Colorado

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    A collection of western toads, Bufo boreas Baird and Girard, 1852, and neotenic tiger salamanders, Ambystoma tigrinum (Green) from Sheep Lake, Horseshoe Park, Rocky Mountain National Park, Colorado, were examined for helminths in the spring of 1966. Oswaldo-Cruzia subauricularis (Rudolphi, 1819) was found in Bufo boreas and Ophiotaenia filarioides (LaRue, 1909) in Ambystoma tigrinum. In addition, both hosts harbored Spironoura pretiosa Ingles, 1936, Phylloclistomum bufonis Frandsen, 1957 and Cephalogonimus americanus. The last species differed greatly in appearance in the two hosts and these differences are reported herein

    Chiropteran Mortality

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    The study of chiropteran mortality is a difficult one because observations concerning mass mortality, predation, and fatal accidents are sporadic and unexpected. Almost every known predaceous animal preys on bats from time to time; but (with one or two rare exceptions) do so only when an occasional opportunity presents itself, and do not specialize in bat predation. Our knowledge of bat pathology is meager. Mass-mortalities have been reported only from sight observations, and the causative organisms rarely ascertained, because of the unexpected encounter. The relationships between human and chiropteran diseases are becoming much better understood; this study is mostly oriented toward man, and not toward the cause and effect of disease in the chiroptera. The longevity of certain bats is known to range between 15 and 20 years; but their unique activities make them rather prone to accident. They become impaled on such sharp objects as barbed wire, and locust, burdock, and cactus spines. They fall into water holes and drown, get entrapped in tar pits, get electrocuted on high-power lines, etc., but remain among the most abundant mammals on earth today. We have attempted to assemble the literature on all known causes of mortality in bats but cannot, of course, cite all noted occurrences

    The Effect of Macro Information Environment Change on the Quality of Management Earnings Forecasts

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    The 1990s were characterized by substantial increases in the performance of and investor reliance on financial analysts. Because managers possess superior private information and issue forecasts to align investors’ expectations with their own, we predict that managers increased the quality of their earnings forecasts during the 1990s in order to keep pace with the improved forward-looking information provided by financial analysts, upon which investors increasingly relied. Using a sample of 2,437 management earnings forecasts, we document an increase in management earnings forecast precision, management earnings forecast accuracy, and managers’ tendency to explain earnings forecasts in 1993-1996 relative to 1983-1986. Given that these forecast characteristics are linked to greater informativeness and credibility, we also document that the information content of management earnings forecasts, as measured by the strength of share price responses to forecast news, increased in 1993 -1996 relative to 1983-1986. As expected, the increased information content of management forecasts primarily occurred for firms covered by financial analysts

    On Empirical Validation of Compactness Measures for Electoral Redistricting and Its Significance for Application of Models in the Social Sciences

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    Use of optimization models in science and policy applications is often problematic because the best available models are very inaccurate representations of the originating problems. Such is the case with electoral districting models, for which there exist no generally accepted measures of compactness, in spite of many proposals and much analytical study. This article reports on an experimental investigation of subjective judgments of compactness for electoral districts. The experiment draws on a unique database of 116 distinct, legally valid districting plans for the Philadelphia City Council, discovered with evolutionary computation. Subjects in the experiment displayed, in the aggregate, remarkable agreement with several standard measures of compactness, thus providing warrant for use of these measures that has heretofore been unavailable. The exercise also lends support to the underlying methodology on display here, which proposes to use models based on subjective judgments in combination with algorithms that find multiple solutions in order to support application of optimization models in contexts in which they are only very approximate representations

    The TLR9 ligand, CpG-ODN, Induces Protection Against Cerebral Ischemia/Reperfusion Injury via Activation of pi3k/Akt Signaling.

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    Toll-like receptors (TLRs) have been shown to be involved in cerebral ischemia/reperfusion (I/R) injury. TLR9 is located in intracellular compartments and recognizes CpG-DNA. This study examined the effect of CpG-ODN on cerebral I/R injury. C57BL/6 mice were treated with CpG-ODN by i.p. injection 1 hour before the mice were subjected to cerebral ischemia (60 minutes) followed by reperfusion (24 hours). Scrambled-ODN served as control-ODN. Untreated mice, subjected to cerebral I/R, served as I/R control. The effect of inhibitory CpG-ODN (iCpG-ODN) on cerebral I/R injury was also examined. In addition, we examined the therapeutic effect of CpG-ODN on cerebral I/R injury by administration of CpG-ODN 15 minutes after cerebral ischemia. CpG-ODN administration significantly decreased cerebral I/R-induced infarct volume by 69.7% (6.4±1.80% vs 21.0±2.85%, P\u3c0.05), improved neurological scores, and increased survival rate, when compared with the untreated I/R group. Therapeutic administration of CpG-ODN also significantly reduced infarct volume by 44.7% (12.6±2.03% vs 22.8±2.54%, P\u3c0.05) compared with untreated I/R mice. Neither control-ODN, nor iCpG-ODN altered I/R-induced cerebral injury or neurological deficits. Nissl staining showed that CpG-ODN treatment preserved neuronal morphology in the ischemic hippocampus. Immunoblot showed that CpG-ODN administration increased Bcl-2 levels by 41% and attenuated I/R-increased levels of Bax and caspase-3 activity in ischemic brain tissues. Importantly, CpG-ODN treatment induced Akt and GSK-3β phosphorylation in brain tissue and cultured microglial cells. PI3K inhibition with LY294002 abolished CpG-ODN-induced protection. CpG-ODN significantly reduces cerebral I/R injury via a PI3K/Akt-dependent mechanism. Our data also indicate that CpG-ODN may be useful in the therapy of cerebral I/R injury

    Western Pacific hydroclimate linked to global climate variability over the past two millennia

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    Interdecadal modes of tropical Pacific ocean-atmosphere circulation have a strong influence on global temperature, yet the extent to which these phenomena influence global climate on multicentury timescales is still poorly known. Here we present a 2,000-year, multiproxy reconstruction of western Pacific hydroclimate from two speleothem records for southeastern Indonesia. The composite record shows pronounced shifts in monsoon rainfall that are antiphased with precipitation records for East Asia and the central-eastern equatorial Pacific. These meridional and zonal patterns are best explained by a poleward expansion of the Australasian Intertropical Convergence Zone and weakening of the Pacific Walker circulation (PWC) between ~1000 and 1500 CE Conversely, an equatorward contraction of the Intertropical Convergence Zone and strengthened PWC occurred between ~1500 and 1900 CE. Our findings, together with climate model simulations, highlight the likelihood that century-scale variations in tropical Pacific climate modes can significantly modulate radiatively forced shifts in global temperature

    On Empirical Validation of Compactness Measures for Electoral Redistricting and Its Significance for Application of Models in the Social Sciences

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    Use of optimization models in science and policy applications is often problematic because the best available models are very inaccurate representations of the originating problems. Such is the case with electoral districting models, for which there exist no generally accepted measures of compactness, in spite of many proposals and much analytical study. This article reports on an experimental investigation of subjective judgments of compactness for electoral districts. The experiment draws on a unique database of 116 distinct, legally valid districting plans for the Philadelphia City Council, discovered with evolutionary computation. Subjects in the experiment displayed, in the aggregate, remarkable agreement with several standard measures of compactness, thus providing warrant for use of these measures that has heretofore been unavailable. The exercise also lends support to the underlying methodology on display here, which proposes to use models based on subjective judgments in combination with algorithms that find multiple solutions in order to support application of optimization models in contexts in which they are only very approximate representations. </jats:p
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