5,539 research outputs found

    Determination of optimal reversed field with maximal electrocaloric cooling by a direct entropy analysis

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    Application of a negative field on a positively poled ferroelectric sample can enhance the electrocaloric cooling and appears as a promising method to optimize the electrocaloric cycle. Experimental measurements show that the maximal cooling does not appear at the zero-polarization point, but around the shoulder of the P-E loop. This phenomenon cannot be explained by the theory based on the constant total entropy assumption under adiabatic condition. In fact, adiabatic condition does not imply constant total entropy when irreversibility is involved. A direct entropy analysis approach based on work loss is proposed in this work, which takes the entropy contribution of the irreversible process into account. The optimal reversed field determined by this approach agrees with the experimental observations. This study signifies the importance of considering the irreversible process in the electrocaloric cycles

    Multiple Role Women and their Spouses: Variables Effecting Family Functioning

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    The purpose of this study was to examine the effect of age, education, perceived child care support, social support, role conflict, coping and marital adjustment on family functioning as experienced by multiple role women and their spouses. The family has long been recognized as the most important contextual influence in human growth and development. Nurses have been working with families for generations, especially in community and mental health nursing. It is only in the last decade, however, that there has been an increasing interest in family research among nurses reflected in a trend away from individual-focused studies and toward a whole family perspective. The theoretical framework for this study was derived from the stress and coping paradigm of Lazarus and Folkman (1984) with support of the linkages offered through the literature review. The correlational design of this investigation was based on a temporally ordered causal recursive model. One hundred multiple role women and their spouses were selected using a computerized random sampling from membership listings of employed members of a large organization. This sample provided a cross-section of many professional disciplines. Descriptive, correlational, and inferential statistics were used to analyze the data. Family cohesion, as a component of family functioning, had 50% of the variance explained, with family role conflict and marital adjustment being the strongest predictor variables for the total sample of men and women. A comparison of the results by gender revealed that social support and coping were more predictive for men, while interrole conflict was more predictive for women. Marital adjustment was the most potent predictor for both groups. Family cohesion, as a component of family functioning, had 43% of the variance explained for the men, and 52% of the variance explained for the women by the predictor variables. Further examination of group differences revealed that women reported significantly more perceived emotional support from relatives, friends, and neighbors than men, while men reported more perceived emotional and informational support from work supervisors than did the women respondents. Women reported more frequent use of confrontive and fantasy coping patterns than men

    Power profiles of competitive and noncompetitive mountain bikers

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    © 2017 National Strength and Conditioning Association. The performance of Olympic distance cross-country mountain bikers (XCO-MTB) is affected by constraints such as erosion of track surfaces and mass start congestion which can affect race results. Standardized laboratory assessments quantify interseasonal and intraseasonal cycling potential through the assessment of multiple physiological capacities. Therefore, this study examined whether the power profile assessment (PPA) could discriminate between competitive XCO-MTB and noncompetitive mountain bikers (NC-MTB). Second, it aimed to report normative power profile data for competitive XCO-MTB cyclists. Twenty-nine male participants were recruited across groups of XCO-MTB (n = 14) and NC-MTB (n = 15) mountain bikers. Each cyclist completed a PPA that consisted of increasing duration maximal efforts (6, 15, 30, 60, 240, and 600 seconds) that were interspersed by longer rest periods (174, 225, 330, 480, and 600 seconds) between efforts. Normative power outputs were established for XCO-MTB cyclists ranging between 13.8 ± 1.5 W·kg -1 (5-second effort) and 4.1 ± 0.6 W·kg -1 (600-second effort). No differences in absolute peak power or cadence were identified between groups across any effort length (p > 0.05). However, the XCO-MTB cyclists produced greater mean power outputs relative to body mass than the NC-MTB during the 60-second (6.9 ± 0.8 vs 6.4 ± 0.6 W·kg -1 ; p = 0.002), 240-second (4.7 ± 0.7 vs. 3.8 ± 0.4 W·kg -1 ; p < 0.001), and 600-second (4.1 ± 0.6 vs. 3.4 ± 0.3 W·kg -1 ; p < 0.001) efforts. The PPA is a useful discriminative assessment tool for XCO-MTB and highlights the importance of aerobic power for XCO-MTB performance

    Coercivity extrema in melt-spun CuCo ribbons: Effects of the magnetic moment distribution

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    Measurements of magnetization loops on melt-spun CuCo ribbons revealed a minimum in the temperature dependence of the coercivity. A coherent interpretation was given through Monte Carlo simulations of a dispersed system of noninteracting, uniaxial magnetic granules embedded in a nonmagnetic matrix. The coercivity is implicitly defined by the balance between the negative magnetization of superparamagnetic granules and the remaining magnetization of blocked granules after saturation in the positive field direction. When the temperature rises in a system made of a large amount of small granules and a small amount of big granules, unblocking predominates over thermal fluctuations and the coercivity decreases until a certain temperature at which most of the small granules are superparamagnetic; above this temperature, thermal fluctuations predominate, and the coercivity increases almost linearly with the temperature until the final unblocking of the big granules. (C) 1999 American Institute of Physics. [S0021-8979(99)04618-6].8663010301

    Fluorescence activated cell sorting-A selective tool for plant cell isolation and analysis

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    Instrumentation for flow cytometry and sorting is designed around the assumption that samples are single-cell suspensions. However, with few exceptions, higher plants comprise complex multicellular tissues and organs, in which the individual cells are held together by shared cell walls. Single-cell suspensions can be obtained through digestion of the cells walls and release of the so-called protoplasts (plants without their cell wall). Here we describe best practices for protoplast preparation, and for analysis through flow cytometry and cell sorting. Finally, the numerous downstream applications involving sorted protoplasts are discussed

    GABAergic neurons regulate lateral ventricular development via transcription factor Pax5

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    Postmortem studies have revealed a downregulation of the transcription factor Pax5 in GABAergic neurons in bipolar disorder, a neurodevelopmental disorder, raising the question whether Pax5 in GABAergic neurons has a role in normal brain development. In a genetic approach to study functions of Pax5 in GABAergic neurons, Pax5 was specifically deleted in GABAergic neurons from Pax5 floxed mice using a novel Gad1-Cre transgenic mouse line expressing Cre recombinase in Gad1-positive, i.e. GABAergic neurons. Surprisingly, these mice developed a marked enlargement of the lateral ventricles at approximately seven weeks of age, which was lethal within 1–2 weeks of its appearance. This hydrocephalus phenotype was observed in mice homozygous or heterozygous for the Pax5 conditional knockout, with a gene dosage-dependent penetrance. By QTL (quantitative trait loci) mapping, a 3.5 Mb segment on mouse chromosome 4 flanked by markers D4Mit237 and D4Mit214 containing approximately 92 genes including Pax5 has previously been linked to differences in lateral ventricular size. Our findings are consistent with Pax5 being a relevant gene underlying this QTL phenotype and demonstrate that Pax5 in GABAergic neurons is essential for normal ventricular development

    Performance analysis in esports: modelling performance at the 2018 League of Legends World Championship

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    © The Author(s) 2020. Performance analysis is a well-established discipline in sports science, supported by decades of research. Comparatively, performance analysis in electronic sports (esports) is limited. Therefore, there is an opportunity to accelerate performance outcomes in esports by applying methods grounded in sports science. This study adopted a coach-centred approach to model performance at the 2018 League of Legends World Championship. Three expert coaches rated the proposed relationship between 43 variables and match outcomes in professional League of Legends competition using a Likert scale (1–10). The Likert scale was anchored with ‘no relationship’ at 1 and ‘very strong relationship’ at 10. The coaches’ median ratings were calculated for each variable. Variables with a median score ≥6 were retained for analyses. A total of 14 variables were collected from the 2018 League of Legends World Championship (n = 119) matches via video annotations and match histories. Generalized Linear Mixed Effects Models with binomial logit link function were implemented with respect to the Blue Side winning or losing the match, and individual teams were specified as random effects. Variables were screened for multicollinearity before using a step-up approach. The best model of performance included Tower Percentage (p = 0.006) and Number of Inhibitors (p = 0.029). This model achieved classification accuracy of 95.8%. While Tower Percentage and Number of Inhibitors contributed to winning or losing, further research is required to determine effective strategies to improve these variables, to understand the relevance of these variables across the complete time-series of the match, and to determine whether performance indicators remain stable across game updates

    Observation of an unusual field dependent slow magnetic relaxation and two distinct transitions in a family of new complexes

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    An unusual field dependent slow magnetic relaxation and two distinct transitions were observed in a family of new rare earth-transition metal complexes, [Ln (bipy) (H2_{2}O)4_{4} M(CN)6_{6}] â‹…\cdot 1.5 (bipy) â‹… \cdot 4H2_{2}O (bipy = 2,2'-bipyridine; Ln = Gd3+^{3+},Y3+^{3+}; M = Fe3+ ^{3+}, Co3+^{3+}). The novel magnetic relaxation, which is quite different from those in normal spin glasses and superparamagnets but very resembles qualitatively those in single-molecule magnet Mn12_{12}-Ac even if they possess different structures, might be attributed to the presence of frustration that is incrementally unveiled by the external magnetic field. The two distinct transitions in [GdFe] were presumed from DC and AC susceptibility as well as heat capacity measurements.Comment: Revtex, 6 figure

    A multifactorial comparison of Australian youth soccer players' performance characteristics

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    © The Author(s) 2019. The current study aimed to investigate the performance characteristics that discriminate Australian youth soccer players according to their academy status. A total of 165 youth soccer players participated in this study and were sub-divided into either an early adolescence (n = 92, age = 13.0 ± 0.6 years) or mid-adolescence (n = 73 age = 14.8 ± 0.6 years) group. Players completed multifactorial assessments of anthropometry, motor competence, physical fitness, decision-making and psychological traits. Statistical significance was set at p ≤ 0.05. Multivariate analysis of variance identified dynamic balancing ability (both age groups), object manipulation (mid-adolescence), lateral jumping ability (both age groups), linear speed over 5 m (both age groups), change of direction skill (mid-adolescence), intermittent aerobic endurance (mid-adolescence) and total response time on a decision-making assessment (early adolescence) to discriminate academy status. Interestingly, a binomial logistical regression showed that a 0.1 s decrease in sprint time (i.e. running faster) increased the odds of a player belonging to a tier one academy by 19% and 47% for early and mid-adolescent players, respectively. Overall, performance in the motor competence and physical fitness assessments were in favour of the tier one academy players. These findings are indicative of a potential selection bias in the Australian talent pool or a training effect whereby tier one academy programmes emphasise the development of physical attributes. However, future research is required to further substantiate this in a larger sample of youth soccer players from other playing regions within Australia

    Restrictive ID policies: implications for health equity

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    We wish to thank Synod Community Services for their critical work to develop, support, and implement a local government-issued ID in Washtenaw County, MI. We also thank Yousef Rabhi of the Michigan House of Representatives and Janelle Fa'aola of the Washtenaw ID Task Force, Lawrence Kestenbaum of the Washtenaw County Clerk's Office, Sherriff Jerry Clayton of the Washtenaw County Sherriff's Office, and the Washtenaw ID Task Force for their tireless commitment to developing and supporting the successful implementation of the Washtenaw ID. Additionally, we thank Vicenta Vargas and Skye Hillier for their contributions to the Washtenaw ID evaluation. We thank the Curtis Center for Research and Evaluation at the University of Michigan School of Social Work, the National Center for Institutional Diversity at the University of Michigan, and the University of California-Irvine Department of Chicano/Latino Studies and Program in Public Health for their support of the Washtenaw ID community-academic research partnership. Finally, we thank the reviewers for their helpful comments on earlier drafts of this manuscript. (Curtis Center for Research and Evaluation at the University of Michigan School of Social Work; National Center for Institutional Diversity at the University of Michigan; University of California-Irvine Department of Chicano/Latino Studies; Program in Public Health)https://link.springer.com/content/pdf/10.1007/s10903-017-0579-3.pdfPublished versio
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