5,591 research outputs found

    Interregional Analysis of Interstate Dairy Compacts

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    Livestock Production/Industries, Marketing,

    Market Orientation Within University Schools Of Business: Can A Dynamical Systems Viewpoint Applied To A Non-Temporal Data Set Yield Valuable Insights For University Managers?

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    This study investigates the use of using complexity theory – the study of nonlinear dynamical systems of which chaos and catastrophe theory are subsets – in the analysis of a non temporal data set to derive valuable insights into the functioning of university schools of business. The approach is unusual in that studies of nonlinearity in complex dynamical systems typically involve longitudinal data.  Challenges associated with such studies usually involve establishing nonlinearity, obtaining a data set with a sufficient number of entries, and robust mathematical and computational requirements for effective analysis.  The format of the paper is as follows: 1) a general description of complex systems is presented which identifies a number of generally accepted characteristics of complex systems, 2) a description of the data set and the research technique utilized, 3) a presentation of the data set as an “attractor” landscape as typically defined in complex systems analysis, 4) potential insights that may be derived from the analysis; and 5) conclusions and recommendations for further study.  The value of the study is to demonstrate that within the framework of complexity theory, non longitudinal data may be used to derive valuable managerial insights into the functioning of organizations such as university schools of business

    Natural Selection on Thermal Performance in a Novel Thermal Environment

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    Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming

    Do nonphysical punishments reduce antisocial behavior more than spanking? a comparison using the strongest previous causal evidence against spanking

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    <p>Abstract</p> <p>Background</p> <p>The strongest causal evidence that customary spanking increases antisocial behavior is based on prospective studies that control statistically for initial antisocial differences. None of those studies have investigated alternative disciplinary tactics that parents could use instead of spanking, however. Further, the small effects in those studies could be artifactual due to residual confounding, reflecting child effects on the frequency of all disciplinary tactics. This study re-analyzes the strongest causal evidence against customary spanking and uses these same methods to determine whether alternative disciplinary tactics are more effective in reducing antisocial behavior.</p> <p>Methods</p> <p>This study re-analyzed a study by Straus et al.<abbrgrp><abbr bid="B1">1</abbr></abbrgrp> on spanking and antisocial behavior using a sample of 785 children who were 6 to 9 years old in the 1988 cohort of the American National Longitudinal Survey of Youth. The comprehensiveness and reliability of the covariate measure of initial antisocial behavior were varied to test for residual confounding. All analyses were repeated for grounding, privilege removal, and sending children to their room, and for psychotherapy. To account for covarying use of disciplinary tactics, the analyses were redone first for the 73% who had reported using at least one discipline tactic and second by controlling for usage of other disciplinary tactics and psychotherapy.</p> <p>Results</p> <p>The apparently adverse effect of spanking on antisocial behavior was replicated using the original trichotomous covariate for initial antisocial behavior. A similar pattern of adverse effects was shown for grounding and psychotherapy and partially for the other two disciplinary tactics. All of these effects became non-significant after controlling for latent comprehensive measures of externalizing behavior problems.</p> <p>Conclusions</p> <p>These results are consistent with residual confounding, a statistical artifact that makes all corrective actions by parents and psychologists appear to increase children's antisocial behavior due to child effects on parents. Improved research methods are needed to discriminate between effective vs. counterproductive implementations of disciplinary tactics. How and when disciplinary tactics are used may be more important than which type of tactic is used.</p

    Managing Complex Dynamical Systems

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    Management commonly engages in a variety of research designed to provide insight into the motivation and relationships of individuals, departments, organizations, etc. This paper demonstrates how the application of concepts associated with the analysis of complex systems applied to such data sets can yield enhanced insights for managerial action

    Functional anatomy of the masking level difference, an fMRI study

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    Introduction: Masking level differences (MLDs) are differences in the hearing threshold for the detection of a signal presented in a noise background, where either the phase of the signal or noise is reversed between ears. We use N0/Nπ to denote noise presented in-phase/out-of-phase between ears and S0/Sπ to denote a 500 Hz sine wave signal as in/out-of-phase. Signal detection level for the noise/signal combinations N0Sπ and NπS0 is typically 10-20 dB better than for N0S0. All combinations have the same spectrum, level, and duration of both the signal and the noise. Methods: Ten participants (5 female), age: 22-43, with N0Sπ-N0S0 MLDs greater than 10 dB, were imaged using a sparse BOLD fMRI sequence, with a 9 second gap (1 second quiet preceding stimuli). Band-pass (400-600 Hz) noise and an enveloped signal (.25 second tone burst, 50% duty-cycle) were used to create the stimuli. Brain maps of statistically significant regions were formed from a second-level analysis using SPM5. Results: The contrast NπS0- N0Sπ had significant regions of activation in the right pulvinar, corpus callosum, and insula bilaterally. The left inferior frontal gyrus had significant activation for contrasts N0Sπ-N0S0 and NπS0-N0S0. The contrast N0S0-N0Sπ revealed a region in the right insula, and the contrast N0S0-NπS0 had a region of significance in the left insula. Conclusion: Our results extend the view that the thalamus acts as a gating mechanism to enable dichotic listening, and suggest that MLD processing is accomplished through thalamic communication with the insula, which communicate across the corpus callosum to either enhance or diminish the binaural signal (depending on the MLD condition). The audibility improvement of the signal with both MLD conditions is likely reflected by activation in the left inferior frontal gyrus, a late stage in the what/where model of auditory processing. © 2012 Wack et al

    Post-metomorphic Growth and Reproduction in the Eastern Narrowmouth Toad (Gastrophryne carolinensis) from Northeastern Arkansas

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    Post-metamorphic growth and the reproductive cycle of the eastern narrowmouth toad (Gastrophryne carolinensis) were studied from 204 individuals collected during the April August 1989 activity season in a two-county area of northeastern Arkansas near the northwestern edge of the species\u27 geographic range. Late summer metamorphs require a full growing season before they can reproduce as they approach their second year of life. The oldest individuals may be at least five years old. By late April, gonadal cycles of adults had commenced; the males were producing sperm, and some of the females were gravid. Fertility of both sexes increased during the season and peaked in June. Males remained fertile through August, but only two gravid females were found after June indicating that adults were physiologically capable of breeding for a period longer than weather conditions were acceptable for oviposition. Neither clutch size nor ovum diameter increased with female body size. Disparity of body size and clutch characteristics throughout the brief breeding season could be explained by deposition of partial clutches. The growth, maturity, and gonadal cycle of this species at the northern edge of its range are similar to findings in southern populations, and climate, not changes inbreeding physiology, constrain breeding at this northern site

    Rubella Immunization of Adult Females Using HPV-77 DK-12 Live Attenuated Rubella Virus

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    This study demonstrates the serologic response as measured by the HAl test and the side reactions of the HPV-77 DK-12 live rubella vaccine in a small group of adult females. One hundred percent seroconversion was obtained using this vaccine. The mean titers obtained in two separate time periods post-vaccination are higher than those reported for several other rubella virus vaccines. A 66% occurrence of joint symptomatology was recorded post-vaccination with a mean duration of 11.6 days; 24% of women who received placebo reported joint complaints which had a mean duration of 2.0 days. The difference between these two rates is somewhat greater than that reported for other HPV-77 strain vaccines and the average duration of these complaints is longer. The other symptoms reported postvaccination seemed insignificant when comparing both the placebo and the vaccine group. One woman became pregnant three months after vaccination and was subsequently therapeutically aborted. At the time of therapeutic abortion, attempts were unsuccessful to recover rubella virus from the products of conception and cervical swabs

    Coronary-artery bypass surgery in patients with ischemic cardiomyopathy

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    BACKGROUND The survival benefit of a strategy of coronary-artery bypass grafting (CABG) added to guideline-directed medical therapy, as compared with medical therapy alone, in patients with coronary artery disease, heart failure, and severe left ventricular systolic dysfunction remains unclear. METHODS From July 2002 to May 2007, a total of 1212 patients with an ejection fraction of 35% or less and coronary artery disease amenable to CABG were randomly assigned to undergo CABG plus medical therapy (CABG group, 610 patients) or medical therapy alone (medical-therapy group, 602 patients). The primary outcome was death from any cause. Major secondary outcomes included death from cardiovascular causes and death from any cause or hospitalization for cardiovascular causes. The median duration of follow-up, including the current extended-follow-up study, was 9.8 years. RESULTS A primary outcome event occurred in 359 patients (58.9%) in the CABG group and in 398 patients (66.1%) in the medical-therapy group (hazard ratio with CABG vs. medical therapy, 0.84; 95% confidence interval [CI], 0.73 to 0.97; P=0.02 by log-rank test). A total of 247 patients (40.5%) in the CABG group and 297 patients (49.3%) in the medical-therapy group died from cardiovascular causes (hazard ratio, 0.79; 95% CI, 0.66 to 0.93; P=0.006 by log-rank test). Death from any cause or hospitalization for cardiovascular causes occurred in 467 patients (76.6%) in the CABG group and in 524 patients (87.0%) in the medical-therapy group (hazard ratio, 0.72; 95% CI, 0.64 to 0.82; P&lt;0.001 by log-rank test). CONCLUSIONS In a cohort of patients with ischemic cardiomyopathy, the rates of death from any cause, death from cardiovascular causes, and death from any cause or hospitalization for cardiovascular causes were significantly lower over 10 years among patients who underwent CABG in addition to receiving medical therapy than among those who received medical therapy alone. (Funded by the National Institutes of Health; STICH [and STICHES] ClinicalTrials.gov number, NCT00023595.
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