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131.
Marco Del Giudice 《Multivariate behavioral research》2013,48(4):571-573
In a previous paper (Del Giudice, 2017 [Heterogeneity coefficients for Mahalanobis' D as a multivariate effect size. Multivariate Behavioral Research, 52, 216–221]), I proposed two heterogeneity coefficients for Mahalanobis' D based on the Gini coefficient, labeled H and EPV. In this addendum I discuss the limitations of the original approach and note that the proposed indices may overestimate heterogeneity under certain conditions. I then describe two revised indices H2 and EPV2, and illustrate the difference between the original and revised indices with some real-world data sets. 相似文献
132.
We report on the effect of cooling rate on the size-dependent atomic ordering of CoPt nanoparticles using aberration corrected high-resolution transmission electron microscopy. It was found that cooling rate plays a crucial role in promoting atomic ordering during the cooling process after annealing. Nanoparticles of ≈3?nm in diameter show the A1-disordered phase after annealing at 873?K for 1?h followed by rapid cooling (110?K/min), while the L10-ordered phase is obtained when the cooling rate is slow (1.5?K/min). The disordered phase is also obtained by rapid cooling after annealing at 973?K for 1?h. These results unambiguously indicate that the order–disorder transformation temperature is reduced to a temperature at least lower than 873?K for CoPt nanoparticles smaller than 3?nm in diameter. The slow cooling process promotes the atomic ordering, which resulted in an enhancement of magnetic coercivity as high as 2200?Oe. This study demonstrates that hard magnetic properties of the CoPt nanoparticles can be improved by controlling the cooling rate after heat treatments. 相似文献
133.
The mechanical softening behaviour of micrometre-scale metals (free-standing metal foils and wires) with decreasing either the geometrical or the microstructural scale (i.e. the smaller, the weaker) has recently been reported. Here, we present a mechanism-based model to understand the softening behaviour, which is based on competition between the effects of surface grain relaxation and the interior grain strengthening effect. The model describes well the yield stress of Cu foils with different ratios of the thickness to grain size. 相似文献
134.
A key challenge in the fabrication of superhard nanocomposite films is how to control the distribution of grain sizes in these materials. High-resolution transmission electron microscopy has been used to measure nanograin-size distributions in the Ti–B–N films with various B contents. The results show that the mean grain size decreases with increase of B content and the grain-size distribution conforms to a log-normal function when the hardness approaches a maximum value. The transition from normal to log-normal distributions can be determined by analysis in terms of a minimum information criterion. The origin of a log-normal size distribution probably results from heterogeneity arising from a diffusion-drift process. 相似文献
135.
The grain size variation in a gradient surface produced by a punching and recovery process on a Cu-30Ni alloy has been observed by atomic force microscopy. The friction characteristics of the gradient surface in a 3.5 wt% NaCl solution were investigated using a micro-indenter probe, a pin-on-disc type tribometer, a strain sensor and an optical microscope. The results showed that the hardness and grain size can be well represented by the Hall–Petch relationship when the gain size is more than 30?nm. The wear rate, friction coefficient and adhesive force all increase depth below the surface. These variations are attributed to a gradual increasing grain size with depth. The morphologies of the worn track were also studied to understand further the corrosive wear behaviour of gradient surfaces. 相似文献
136.
Clive D. Field 《Religion》2014,44(3):357-382
AbstractThe British religious census of 2011 is located in its broader historical and methodological context. The principal developments in the measurement of religious affiliation (proxy-assigned or self-assigned) in Britain are traced from the Reformation to the present day, charting the relative contribution of the Churches, the State and empirical social science. The key statistics which have emerged from their respective efforts are summarised, with nominal religious affiliation universal until the time of the French Revolution and preponderant until as late as the 1980s. For recent decades, when the profession of faith has been rejected by large numbers of Britons, particular attention is paid to the variant results from different question-wording. Depending upon what is asked, the proportion of the population currently making sense of their lives without asserting a confessional religious identity ranges from one-quarter to one-half. The difficulties of trying to construct a religious barometer through a single, unitary indicator are thus illuminated. 相似文献
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139.
Petersen, T., Elklit, A. & Olesen, J. G. (2010). Victimization and PTSD in a Faroese youth total-population sample. Scandinavian Journal of Psychology, 51, 56–62.
The prevalence of twenty traumatic events and negative life events in relation to posttraumatic stress disorder (PTSD) was studied in a Faroese total-population sample of 687 eighth-grade students with a mean age of 14.2 years. Ninety-four percent of the females and 89% of the males were directly exposed to or had witnessed at least one traumatic event or a negative life event. The odds ratios for PTSD after direct and indirect exposure to specific events are described. The lifetime prevalence of PTSD was 20%, whereas another 14% reached a subclinical level of PTSD. After exposure, females had PTSD more than twice as often as males. Being exposed to multiple traumatic events, living with a single parent, and having experienced a traumatic event or a negative life event within the last year were all associated with PTSD and its subscales. 相似文献
The prevalence of twenty traumatic events and negative life events in relation to posttraumatic stress disorder (PTSD) was studied in a Faroese total-population sample of 687 eighth-grade students with a mean age of 14.2 years. Ninety-four percent of the females and 89% of the males were directly exposed to or had witnessed at least one traumatic event or a negative life event. The odds ratios for PTSD after direct and indirect exposure to specific events are described. The lifetime prevalence of PTSD was 20%, whereas another 14% reached a subclinical level of PTSD. After exposure, females had PTSD more than twice as often as males. Being exposed to multiple traumatic events, living with a single parent, and having experienced a traumatic event or a negative life event within the last year were all associated with PTSD and its subscales. 相似文献
140.
Wendy K Schaefer Richard N. Maclennan Sandra A. Yaholnitsky-smith E. Diane Stover 《Psychology & health》2013,28(5):873-881
Abstract This study examined the psychometric properties of the Eating Disorder Inventory (EDI) with a clinical sample of 79 female clients seen at an outpatient eating disorder program. The means and standard deviations for the bulimia nervosa subgroup in this study (n = 48) compared favorably with the bulimia group in the EDI Manual Supplement (1986) on all eight subscales, except Drive for Thinness. The present non-student sample had significantly lower scores on this particular subscale than did the norm group (mostly students). Another difference was that the local bulimic subgroup had significantly higher present and minimum weights (as a percentage of the expected average weight according to height). The EDI subscales also displayed respectable internal consistency reliability with this sample. In contrast to previous research, however, only five factors were found in a factor analysis rather than eight corresponding to the original subscales for the EDI. Differences between bulimic and a not-otherwise-specified (NOS) diagnostic groups were also found on both the EDI Ineffectiveness and Bulimia subscales (NOS had lower scores). The results of this study are discussed in terms of the importance of undertaking local standardization of tests in clinical settings. 相似文献