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Quantitative and Qualitative Approaches to Identifying Migration Chronology in a Continental Migrant
William S. Beatty Dylan C. Kesler Elisabeth B. Webb Andrew H. Raedeke Luke W. Naylor Dale D. Humburg 《PloS one》2013,8(10)
The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos) equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international), whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result, targeted conservation plans can be developed to support planning for habitat management and evaluation of long-term climate effects. 相似文献
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Intimate partner violence (IPV) is a risk factor for HIV acquisition in many settings, but little is known about its impact on cellular immunity especially in HIV infected women, and if any impact differs according to the form of IPV. We tested hypotheses that exposure to IPV, non-partner rape, hunger, pregnancy, depression and substance abuse predicted change in CD4+ and CD8+ T-cell count in a dataset of 103 HIV infected young women aged 15-26 enrolled in a cluster randomised controlled trial. Multiple regression models were fitted to measure rate of change in CD4 and CD8 and including terms for age, person years of CD4+/CD8+ T-cell observation, HIV positivity at baseline, and stratum. Exposure variables included drug use, emotional, physical or sexual IPV exposure, non-partner rape, pregnancy and food insecurity. Mean CD4+ T cell count at baseline (or first HIV+ test) was 567.6 (range 1121-114). Participants were followed for an average of 1.3 years. The magnitude of change in CD4 T-cells was significantly associated with having ever experienced emotional abuse from a current partner at baseline or first HIV+ test (Coeff -132.9 95% CI -196.4, -69.4 p<0.0001) and drug use (Coeff -129.9 95% CI -238.7, -21.2 p=0.02). It was not associated with other measures. The change in CD8 T-cells was associated with having ever experienced emotional abuse at baseline or prior to the first HIV+ test (Coeff -178.4 95%CI -330.2, -26.5 p=0.02). In young ART-naive HIV positive women gender-based violence exposure in the form of emotional abuse is associated with a faster rate of decline in markers of cellular immunity. This highlights the importance of attending to emotional abuse when studying the physiological impact of IPV experience and the mechanisms of its impact on women’s health. 相似文献
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Yanga Z. Zembe Loraine Townsend Anna Thorson Margrethe Silberschmidt Anna Mia Ekstrom 《PloS one》2015,10(11)
Introduction
This paper aims to assess the extent and correlates of intimate partner violence (IPV), explore relationship power inequity and the role of sexual and social risk factors in the production of violence among young women aged 16–24 reporting more than one partner in the past three months in a peri-urban setting in the Western Cape, South Africa. Recent estimates suggest that every six hours a woman is killed by an intimate partner in South Africa, making IPV a leading public health problem in the country. While there is mounting evidence that levels of IPV are high in peri-urban settings in South Africa, not much is known about how it manifests among women who engage in concomitantly high HIV risk behaviours such as multiple sexual partnering, transactional sex and age mixing. We know even less about how such women negotiate power and control if exposed to violence in such sexual networks.Methods
Two hundred and fifty nine women with multiple sexual partners, residing in a predominantly Black peri-urban community in the Western Cape, South Africa, were recruited into a bio-behavioural survey using Respondent Driven Sampling (RDS). After the survey, focus group discussions and individual interviews were conducted among young women and men to understand the underlying factors informing their risk behaviours and experiences of violence.Findings
86% of the young women experienced IPV in the past 12 months. Sexual IPV was significantly correlated with sex with a man who was 5 years or older than the index female partner (OR 1.7, 95% CI 1.0–3.2) and transactional sex with most recent casual partner (OR 2.1, 95% CI 1.1–3.8). Predictably, women experienced high levels of relationship power inequity. However, they also identified areas in their controlling relationships where they shared decision making power.Discussion
Levels of IPV among young women with multiple sexual partners were much higher than what is reported among women in the general population and shown to be associated with sexual risk taking. Interventions targeting IPV need to address sexual risk taking as it heightens vulnerability to violence. 相似文献5.
Weihai Zhan Alla V. Shaboltas Roman V. Skochilov Tatiana V. Krasnoselskikh Nadia Abdala 《PloS one》2013,8(7)
Objectives
To examine correlates of perpetration and victimization of intimate partner violence (IPV) under and not under the influence of a substance, we conducted a study among women in Russia.Methods
In 2011, a cross-sectional survey was conducted among patients receiving services at a clinic for sexually transmitted infections in St. Petersburg, Russia. Multinomial logistic regression was used for analysis.Results
Of 299 women, 104 (34.8%) and 113 (37.8%) reported a history of IPV perpetration and victimization, respectively. Nearly half (47.1%) of perpetrators and 61.1% of victims reported that the latest IPV event (perpetration and victimization, respectively) was experienced under the influence of a substance. Factors independently associated with IPV victimization under the influence of a substance were alcohol misuse and a higher number of lifetime sex partners, whereas only experience of childhood abuse (emotional and physical abuse) was independently associated with IPV victimization that did not occur under the influence of a substance. Childhood physical abuse, lower age of first sex, sensation seeking, and alcohol misuse were independently associated with IPV perpetration under the influence of a substance, while only childhood abuse (emotional and physical abuse) was independently associated with IPV perpetration that did not occur under the influence of a substance.Conclusions
IPV under and not under the influence of a substance had different correlates (e.g., alcohol misuse and sensation seeking). Despite the strong association between substance use and IPV, experience of childhood abuse is an important predictor of IPV perpetration and victimization in Russia, above and beyond substance use. 相似文献6.
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Junling Luo Shaohua Tang Xiaojue Peng Xiaohong Yan Xinhua Zeng Jun Li Xiaofei Li Gang Wu 《PloS one》2015,10(10)
To understand the cross-talk and specificity of the early responses of plants to salt and drought, we performed physiological and proteome analyses of Brassica napus seedlings pretreated with 245 mM NaCl or 25% polyethylene glycol (PEG) 6000 under identical osmotic pressure (-1.0 MPa). Significant decreases in water content and photosynthetic rate and excessive accumulation of compatible osmolytes and oxidative damage were observed in response to both stresses. Unexpectedly, the drought response was more severe than the salt response. We further identified 45 common differentially expressed proteins (DEPs), 143 salt-specific DEPs and 160 drought-specific DEPs by isobaric tags for relative and absolute quantitation (iTRAQ) analysis. The proteome quantitative data were then confirmed by multiple reaction monitoring (MRM). The differences in the proteomic profiles between drought-treated and salt-treated seedlings exceeded the similarities in the early stress responses. Signal perception and transduction, transport and membrane trafficking, and photosynthesis-related proteins were enriched as part of the molecular cross-talk and specificity mechanism in the early responses to the two abiotic stresses. The Ca2+ signaling, G protein-related signaling, 14-3-3 signaling pathway and phosphorylation cascades were the common signal transduction pathways shared by both salt and drought stress responses; however, the proteins with executive functions varied. These results indicate functional specialization of family proteins in response to different stresses, i.e., CDPK21, TPR, and CTR1 specific to phosphorylation cascades under early salt stress, whereas STN7 and BSL were specific to phosphorylation cascades under early drought stress. Only the calcium-binding EF-hand family protein and ZKT were clearly identified as signaling proteins that acted as cross-talk nodes for salt and drought signaling pathways. Our study provides new clues and insights for developing strategies to improve the tolerance of crops to complex, multiple environmental stresses. 相似文献
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Mechanisms that contribute to differences in motor performance between young and old adults. 总被引:14,自引:0,他引:14
Roger M Enoka Evangelos A Christou Sandra K Hunter Kurt W Kornatz John G Semmler Anna M Taylor Brian L Tracy 《Journal of electromyography and kinesiology》2003,13(1):1-12
This paper examines the physiological mechanisms responsible for differences in the amplitude of force fluctuations between young and old adults. Because muscle force is a consequence of motor unit activity, the potential mechanisms include both motor unit properties and the behavior of motor unit populations. The force fluctuations, however, depend not only on the age of the individual but also on the muscle group performing the task, the type and intensity of the muscle contraction, and the physical activity status of the individual. Computer simulations and experimental findings performed on tasks that involved single agonist and antagonist muscles suggest that differences in force fluctuations are not attributable to motor unit twitch force, motor unit number, or nonuniform activation of the agonist muscle, but that they are influenced by the variability and common modulation of motor unit discharge in both the agonist and antagonist muscles. Because the amplitude of the force fluctuations does not vary linearly with muscle activation, these results suggest that multiple mechanisms contribute to the differences in force fluctuations between young and old adults, although the boundary conditions for each mechanism remain to be determined. 相似文献
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Analysis of mRNAs that Accumulate in Response to Low Temperature Identifies a Thiol Protease Gene in Tomato 总被引:13,自引:5,他引:8 下载免费PDF全文
We have studied the induction of gene expression at low temperature by cloning mRNAs that accumulate when unripe tomato (Lycopersicon esculentum) fruit are incubated at 4°C. Two cloned mRNAs, C14 and C17, accumulate relatively rapidly in response to cold treatment, while a third, C19, displays a delayed response. Significant levels of these mRNAs were not detected during fruit ripening at normal temperature. We have analyzed gene expression at different temperatures and detect half-maximal accumulation of the C14 and C17 mRNAs at 16°C and 11°C, respectively, and have observed that sustained gene expression requires continuous cold treatment. Furthermore, the level of C14 and C17 gene expression in cold-tolerant (hybrid L. esculentum/Lycopersicon pimpinellifolium) fruit is different from that in cold-sensitive (L. esculentum) fruit. DNA sequence analysis indicates that the C14 mRNA encodes a polypeptide with a region that is homologous to the plant thiol proteases actinidin and papain and to the animal thiol protease cathepsin H. We conclude from these experiments that low temperature selectively induces the expression of specific genes and that one such gene encodes a thiol protease. 相似文献
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John R. Houser Craig Barnhart Daniel R. Boutz Sean M. Carroll Aurko Dasgupta Joshua K. Michener Brittany D. Needham Ophelia Papoulas Viswanadham Sridhara Dariya K. Sydykova Christopher J. Marx M. Stephen Trent Jeffrey E. Barrick Edward M. Marcotte Claus O. Wilke 《PLoS computational biology》2015,11(8)
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Background
MicroRNAs (miRNAs) are endogenous non-coding small RNAs (sRNAs) that can base pair with their target mRNAs, which represses their translation or induces their degradation in various biological processes. To identify miRNAs regulated by heavy metal stress, we constructed two sRNA libraries for the blood clam Tegillarca granosa: one for organisms exposed to toxic levels of cadmium (Cd) and one for a control group.Results
Sequencing of the two libraries and subsequent analysis revealed 215 conserved and 39 new miRNAs. Most of the new miRNAs in T. granosa were up- or down-regulated in response to Cd exposure. There were significant differences in expression between the Cd and control groups for 16 miRNAs. Of these, five miRNAs were significantly up-regulated and 11 were significantly down-regulated in the Cd stress library. Potential targets were predicted for the 16 differential miRNAs in pre-miRNAs identified according to sequence homology. Some of the predicted miRNA targets are associated with regulation of the response to stress induced by heavy metals. Five differentially expressed miRNAs (Tgr-nmiR-8, Tgr-nmiR-21, Tgr-miR-2a, Tgr-miR-10a-5p, and Tgr-miR-184b) were validated by qRT-PCR.Conclusion
Our study is the first large-scale identification of miRNAs in T. granosa haemocytes. Our findings suggest that some miRNAs and their target genes and pathways may play critical roles in the responses of this species to environmental heavy metal stresses. 相似文献15.
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《Journal of Russian & East European Psychology》2013,51(3-4):271-282
A psychologist faced with the problem of ensuring the necessary degree of reliability of a fact he has discovered usually proceeds along a scientifically well-established path. He defines the problem, isolates the relevant area of investigation, finds a procedure adequate to the problem, and collects the number of cases necessary to ensure the reliability of the discovered fact. The criterion of reliability in these cases is the amount of data the investigator has at hand and the amount of variability in the results obtained. It is generally accepted that when the facts at hand are completely homogeneous, a relatively small number of experiments is sufficient to ensure reliability, whereas if the variability of the obtained data is relatively great, the number of observations required to ensure the statistical reliability of a fact must be increased considerably. 相似文献
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Christopher Bolton Elizabeth G. Wood Gwen S. Scott Roderick J. Flower 《Cellular and molecular neurobiology》2009,29(5):707-717
The potent oxidant peroxynitrite (ONOO−) is formed after the combination of nitric oxide with superoxide and has been closely associated with the pathology of inflammatory
disease. In particular, the generation of ONOO− has been linked to central nervous system disorders including Alzheimer’s and Parkinson’s disease, multiple sclerosis and
bacterial and viral meningitis. Specifically, ONOO− has been implicated in the loss of blood–brain barrier (BBB) integrity during neuroinflammation, but the precise mechanisms
through which the molecule acts to mediate neurovascular breakdown have not been established. The disruptive effects of ONOO− could be mediated by either direct or indirect actions on the endothelial cells that comprise the major component of the
BBB. The current study has comparatively assessed the direct toxic effects of ONOO− on the brain endothelial cell line, b.End3 and C6 astrocytoma and NA neuroblastoma preparations. b.End3 cells were relatively
resistant to ONOO−-induced cell death compared with C6 and NA cultures. The indirect involvement of ONOO− in neuroendothelial disruption was pharmacologically determined via adhesion molecule expression and immunocompetent cell
attachment to b.End3 cells. ONOO−-targeted drugs, including the selective free radical scavenger, uric acid, the decomposition catalyst 5,10,15,20-tetrakis
(4-sulphonatophenyl) porphyrinatoiron (III) (FeTPPS) and the poly(ADP-ribose) polymerase inhibitor N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-(N,N-dimethylamino) acetamide hydrochloride (PJ34) revealed that ONOO− was only partly involved in E-selectin, ICAM-1 and VCAM-1 expression on b.End3 cells and also cytokine-induced T-lymphocyte
attachment to the cell line. The results indicate that ONOO− contributes to b.End3 cell disruption but is not exclusively responsible for the breakdown of neuroendothelial function. 相似文献
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Mathieu Bastard Loretxu Pinoges Suna Balkan Elisabeth Szumilin Cecilia Ferreyra Mar Pujades-Rodriguez 《PloS one》2012,7(11)