4,151 research outputs found

    Consequences of temperature and temperature variability on swimming activity, group structure, and predation of endangered delta smelt

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    The effects of water temperature on individual and group movement behaviour in prey fish can affect ecological interactions such as competition and predation, but how variability in temperature influence fish behaviour is less understood. Of particular concern is how increased warming in tidally fluctuating estuaries may impact the native and endangered delta smelt (Hypomesus transpacificus, Osmeridae). To help address this issue, we tested the effects of increased water temperature (fluctuating [17ā€“21Ā°C] and warm [21Ā°C] acclimated treatments) on juvenile delta smelt individual and group behaviour, response to chemical alarm and predator cues, as well as capacity to evade predation. In addition, predation of delta smelt was tested in the presence of a dominant invasive competitor, Mississippi silversides (Menidia beryllina, Atherinopsidae), as well as comparative predation mortality on Mississippi silversides when isolated. After 7 days of increased temperature treatments, delta smelt in the warm treatment increased swimming velocity, decreased turning angle, and altered group structure with larger inter-individual distances compared to fish in the control (17Ā°C) and fluctuating temperature treatments. Following conspecific and predator chemical alarm cues, delta smelt showed anti-predator responses. Control and fluctuating treatment fish responded to conspecific cues with increased swimming speeds, decreased inter-individual distances and near-neighbour distances, and, after 15 min, fish recovered back to baseline behaviours. In contrast, fish in the warm treatment had not recovered after 15 min, and swimming speeds were maintained at roughly 25 cm/s, close to maximum capabilities. Fish in control and fluctuating treatments showed minimal responses to predator cues, whereas delta smelt exposed to warm conditions significantly increased swimming speeds and decreased turning angle. Predation of delta smelt by largemouth bass (Micropterus salmoides, Centrarchidae) was greatest under the warm treatment, correlating with altered behaviours of delta smelt; however, predation of Mississippi silversides was greater than delta smelt, independent of temperature. This study provides novel insight into the group behaviour of delta smelt, their response to predation, and how prolonged exposure to elevated temperature may induce negative individual and group behaviours causing alterations in predatorā€“prey dynamics. This work highlights the importance of testing ecologically realistic temperature fluctuations in experiments as delta smelt had significantly altered responses to elevated temperature, dependent on variability of warming

    Effects of Age, Gender, Obesity, and Diabetes on the Efficacy and Safety of the Selective A(2A) Agonist Regadenoson Versus Adenosine in Myocardial Perfusion Imaging Integrated ADVANCE-MPI Trial Results

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    ObjectivesTo compare the effects of age, gender, body mass index, and diabetes on the safety and efficacy of regadenoson stress myocardial perfusion imaging, and to assess the noninferiority of regadenoson to adenosine for the detection of reversible myocardial perfusion defects.BackgroundPrevious reports have shown that a fixed unit bolus of regadenoson is safe and noninferior to adenosine for the detection of reversible perfusion defects by radionuclide imaging.MethodsUsing a database of 2,015 patients, we evaluated the effects of age, gender, body mass index, and diabetes on the safety and efficacy of regadenoson compared to adenosine.ResultsFor detection of ischemia relative to adenosine, noninferiority was demonstrated for all patients (agreement rate difference 0%, 95% CI āˆ’6.2% to +6.8%). The average agreement rate between adenosine-adenosine and adenosine-regadenoson were 0.62 Ā± 0.03 and 0.63 Ā± 0.02. Detection of ischemia was also comparable in specific subgroups. Agreement was less for both agents in women versus men with moderate and large areas of ischemia. Compared to adenosine, regadenoson had a lower combined symptom score and less chest pain, flushing, and throat, neck, or jaw pain, but more headache and gastrointestinal discomfort. This was true in nearly all subgroups. Regadenoson patients reported feeling more comfortable (1.7 Ā± .02 vs. 1.9 Ā± 0.03, p < 0.001). Based on the overall tolerability score, women felt less comfortable than men with both stress agents. Image quality was rated good or excellent in 92% for both agents.ConclusionsRegadenoson can be safely administered as a fixed unit bolus and is as efficacious as adenosine in detecting ischemia regardless of age, gender, body mass index, and diabetes. Regadenoson is better tolerated overall and across various subgroups

    Human resource management system strength in times of crisis

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    In times of crisis, employees turn to their managers for information and guidance. When managers share distinctive, consistent, and consensual information (also known as human resource management [HRM] system strength), it is easier for employees to make sense of the information and understand what is expected from them. To date, research has mainly focused on the outcomes of HRM system strength but has remained silent on its antecedents. Thus, we know little about the factors that influence managers when sharing information with their employees. Drawing on insights from research on HRM system strength, attribution, and cross-cultural fields, we suggest that the interaction between managersā€™ motivation (i.e., the severity of a crisis and an organization's reputation) and their general beliefs (i.e., national cultural values: uncertainty avoidance and power distance) can explain HRM system strength in times of crisis. To test our hypotheses, we used HLM to analyze a three-level sample of 368 bi-weekly observations nested in 34 universities within 15 countries. Results show that the positive effects of crisis severity and an organization's reputation on the employment of HRM system strength were stronger in high uncertainty avoidance countries, but weaker in high power distance countries. Theoretical and practical implications are discussed

    Korean women: breast cancer knowledge, attitudes and behaviors

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    INTRODUCTION: Clustered within the nomenclature of Asian American are numerous subgroups, each with their own ethnic heritage, cultural, and linguistic characteristics. An understanding of the prevailing health knowledge, attitudes, and screening behaviors of these subgroups is essential for creating population-specific health promotion programs. METHODS: Korean American women (123) completed baseline surveys of breast cancer knowledge, attitudes, and screening behaviors as part of an Asian grocery store-based breast cancer education program evaluation. Follow-up telephone surveys, initiated two weeks later, were completed by 93 women. RESULTS: Low adherence to the American Cancer Society's breast cancer screening guidelines and insufficient breast cancer knowledge were reported. Participants' receptiveness to the grocery store-based breast cancer education program underscores the importance of finding ways to reach Korean women with breast cancer early detection information and repeated cues for screening. The data also suggest that the Asian grocery store-based cancer education program being tested may have been effective in motivating a proportion of the women to schedule a breast cancer screening between the baseline and follow-up surveys. CONCLUSION: The program offers a viable strategy to reach Korean women that addresses the language, cultural, transportation, and time barriers they face in accessing breast cancer early detection information

    New zebrafish models of neurodegeneration

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    In modern biomedicine, the increasing need to develop experimental models to further our understanding of disease conditions and delineate innovative treatments has found in the zebrafish (Danio rerio) an experimental model, and indeed a valuable asset, to close the gap between in vitro and in vivo assays. Translation of ideas at a faster pace is vital in the field of neurodegeneration, with the attempt to slow or prevent the dramatic impact on the society's welfare being an essential priority. Our research group has pioneered the use of zebrafish to contribute to the quest for faster and improved understanding and treatment of neurodegeneration in concert with, and inspired by, many others who have primed the study of the zebrafish to understand and search for a cure for disorders of the nervous system. Aware of the many advantages this vertebrate model holds, here, we present an update on the recent zebrafish models available to study neurodegeneration with the goal of stimulating further interest and increasing the number of diseases and applications for which they can be exploited. We shall do so by citing and commenting on recent breakthroughs made possible via zebrafish, highlighting their benefits for the testing of therapeutics and dissecting of disease mechanisms

    Use of the q-Gaussian mutation in evolutionary algorithms

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    Copyright @ Springer-Verlag 2010.This paper proposes the use of the q-Gaussian mutation with self-adaptation of the shape of the mutation distribution in evolutionary algorithms. The shape of the q-Gaussian mutation distribution is controlled by a real parameter q. In the proposed method, the real parameter q of the q-Gaussian mutation is encoded in the chromosome of individuals and hence is allowed to evolve during the evolutionary process. In order to test the new mutation operator, evolution strategy and evolutionary programming algorithms with self-adapted q-Gaussian mutation generated from anisotropic and isotropic distributions are presented. The theoretical analysis of the q-Gaussian mutation is also provided. In the experimental study, the q-Gaussian mutation is compared to Gaussian and Cauchy mutations in the optimization of a set of test functions. Experimental results show the efficiency of the proposed method of self-adapting the mutation distribution in evolutionary algorithms.This work was supported in part by FAPESP and CNPq in Brazil and in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grant EP/E060722/1 and Grant EP/E060722/2

    Normal levels of p27Xic1 are necessary for somite segmentation and determining pronephric organ size

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    The Xenopus laevis cyclin dependent kinase inhibitor p27Xic1 has been shown to be involved in exit from the cell cycle and differentiation of cells into a quiescent state in the nervous system, muscle tissue, heart and retina. We show that p27Xic1 is expressed in the developing kidney in the nephrostomal regions. Using over-expression and morpholino oligonucleotide (MO) knock-down approaches we show normal levels of p27Xic1 regulate pronephros organ size by regulating cell cycle exit. Knock-down of p27Xic1 expression using a MO prevented myogenesis, as previously reported; an effect that subsequently inhibits pronephrogenesis. Furthermore, we show that normal levels of p27Xic1 are required for somite segmentation also through its cell cycle control function. Finally, we provide evidence to suggest correct paraxial mesoderm segmentation is not necessary for pronephric induction in the intermediate mesoderm. These results indicate novel developmental roles for p27Xic1, and reveal its differentiation function is not universally utilised in all developing tissues

    Lack of knowledge about sexually transmitted infections among women in North rural Vietnam

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    <p>Abstract</p> <p>Background</p> <p>The serious long-term complications of sexually transmitted infections (STI) in women and newborns are well-documented. Particularly, STI imply considerable social consequences for women. Low STI knowledge has been shown to be associated with unsafe sex. In Vietnam, misconceptions regarding STI exist, and rural women delay seeking care for STI. The aim of the study was to investigate knowledge of STI among women aged 15 to 49 years in a rural district of Vietnam and to evaluate possible associations between socioeconomic factors and STI knowledge.</p> <p>Methods</p> <p>A cross-sectional population-based study using face-to-face interviews was carried out between March and May 2006 in a demographic surveillance site in rural Vietnam. In total, 1805 women aged 15ā€“49 years were randomly selected to participate in the study. The interviews were based on a structured questionnaire including questions on sociodemographic characteristics of the women and their knowledge about STI. Each correct answer was scored 1, incorrect or do not know answer was scored 0. Multivariate analyses were applied to examine associations between socio-economic conditions and STI knowledge. Intra-cluster correlation was calculated to examine similarities of STI knowledge within clusters.</p> <p>Results</p> <p>Of the 1,805 respondents, 78% (73% married vs. 93% unmarried, p < 0.001) did not know any symptoms of STI, 50% could not identify any cause of STI, 59% (54% married vs. 76% unmarried, p < 0.001) did not know that STI can be prevented. Only 31% of the respondents (36% married vs. 14% unmarried, p < 0.001) answered that condom use could protect against STI, and 56% considered partner treatment necessary. Of 40 possible correct answers, the mean knowledge score was 6.5 (range 0ā€“26, median 6). Young, unmarried women and women who lived in the highlands or mountainous areas demonstrated very low levels of STI knowledge (regression coefficients -1.3 and -2.5, respectively, p < 0.001). Experience of an induced abortion was significantly associated with a higher level of knowledge.</p> <p>Conclusion</p> <p>The low levels of STI knowledge found among women of reproductive age in a rural district of Vietnam indicate an urgent need of health education interventions, of which, young and unmarried women should be specifically targeted.</p

    Lower prevalence of drug resistance mutations at first-line virological failure to first-line therapy with atripla vs. tenofovirRemtricitabine/lamivudineRefavirenz administered on a multiple tablet therapy

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    Fixed-dose combination antiretroviral therapy administered as a single-tablet regimen (STR) may improve virologic suppression rates. The effect of STRs on development of resistance when virologic failure occurs on STRs is not known
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