排序方式: 共有29条查询结果,搜索用时 15 毫秒
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Public Organization Review - The aim of this article is to identify whether the commercialization of NGOs has an influence on the crowding out or crowding in effect of volunteer work, and to... 相似文献
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Kulesza Wojciech Chrobot Nina Dolinski Dariusz Muniak Paweł Bińkowska Dominika Grzyb Tomasz Genschow Oliver 《Journal of Nonverbal Behavior》2022,46(3):233-246
Journal of Nonverbal Behavior - Individuals automatically mimic a wide range of different behaviors, and such mimicking behavior has several social benefits. One of the landmark findings in the... 相似文献
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Pawel R. Pordzik 《Statistical Papers》2012,53(2):299-304
Let
[^(\varveck)]{\widehat{\varvec{\kappa}}} and
[^(\varveck)]r{\widehat{\varvec{\kappa}}_r} denote the best linear unbiased estimators of a given vector of parametric functions
\varveck = \varvecKb{\varvec{\kappa} = \varvec{K\beta}} in the general linear models
M = {\varvecy, \varvecX\varvecb, s2\varvecV}{{\mathcal M} = \{\varvec{y},\, \varvec{X\varvec{\beta}},\, \sigma^2\varvec{V}\}} and
Mr = {\varvecy, \varvecX\varvecb | \varvecR \varvecb = \varvecr, s2\varvecV}{{\mathcal M}_r = \{\varvec{y},\, \varvec{X}\varvec{\beta} \mid \varvec{R} \varvec{\beta} = \varvec{r},\, \sigma^2\varvec{V}\}}, respectively. A bound for the Euclidean distance between
[^(\varveck)]{\widehat{\varvec{\kappa}}} and
[^(\varveck)]r{\widehat{\varvec{\kappa}}_r} is expressed by the spectral distance between the dispersion matrices of the two estimators, and the difference between sums
of squared errors evaluated in the model M{{\mathcal M}} and sub-restricted model Mr*{{\mathcal M}_r^*} containing an essential part of the restrictions
\varvecR\varvecb = \varvecr{\varvec{R}\varvec{\beta} = \varvec{r}} with respect to estimating
\varveck{\varvec{\kappa}}. 相似文献
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At present, urban areas cover almost 3% of the Earth’s terrestrial area, and this proportion is constantly increasing. Although urbanization leads to a decline in biodiversity, at the same time it creates extensive habitats that are exploited by an assemblage of organisms, including birds. The species composition and density of birds nesting in towns and cities are determined by the types of buildings, the structure and maturity of urban greenery, and habitat diversity. In contrast, the habitat traits shaping the community of birds wintering in urban areas are not known. The aim of this work was to assess the influence of habitat structure, food resources and the urban effects (pollution, noise, artificial light) on an assemblage of birds overwintering in an urban area. It was carried out in 2014 and 2015 in the city of Kraków (southern Poland), on 56 randomly chosen sample plots, in which the composition, density and interseasonal similarity of bird assemblage were assessed with line transect method. A total of 64 bird species (mean = 17.7 ± 4.9 SD species/plot) was recorded. The mean density was 89.6 ind./km ±63.3 SD. The most numerous species were Great Tit Parus major, Magpie Pica pica, Blackbird Turdus merula, Blue Tit Cyanistes caeruleus, Rook Corvus frugilegus, Fieldfare Turdus pilaris and House Sparrow Passer domesticus. Noise adversely affected species numbers and density, but artificial light acted positively on the density of birds and their interseasonal stability. The species richness and density of birds were also determined by the number of food sources available (e.g. bird-feeders). In addition, the greater the proportion of open areas, the fewer species were recorded. In contrast, the more urban greenery there was, the greater the density of the entire bird assemblage. Urban infrastructure (buildings, roads, refuse tips) had a positive effect on the interseasonal stabilization of the species composition of wintering birds. The results of this work indicate that the urban effect, i.e. noise and light pollution, apart from purely habitat factors, provide a good explanation for the species richness, density and stability of bird assemblage wintering in urban areas. 相似文献
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The article describes the tradition of self-immolation in Eastern Europe as a form of radical protest during periods of structural crisis. The authors describe cases of self-immolation (Ryszard Siwiec, Jan Palach, Evzen Plocek, Musa Mamut) which took place in the communist period, particularly in the 1960s and 1970s. In the context of Eastern European tradition, they also describe the last case of self-immolation, when Piotr Szcz?sny set himself on fire in Warsaw in October 2017 to protest against the authoritarian rule of the Law and Justice (PiS) party in Poland. After this incident, Piotr Szcz?sny and his memory have become an element of the ‘culture of protest’ in Poland. Quotes from his manifesto began to appear on walls and during anti-government demonstrations. Piotr Szcz?sny has also become a protagonist of protest songs. 相似文献
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This paper proposes new classifiers under the assumption of multivariate normality for multivariate repeated measures data
with Kronecker product covariance structures. These classifiers are especially effective when the number of observations is
not large enough to estimate the covariance matrices, and thus the traditional classifiers fail. Computational scheme for
maximum likelihood estimates of required class parameters are also given. The quality of these new classifiers are examined
on some real data. 相似文献
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On pre-test estimation of parametric functions in the general Gauss-Markov model with quadratic risk
Pawel Pordzik 《Statistical Papers》1999,40(4):469-478
The approach to preliminary test estimation based on comparing the weighted quadratic risk function of two competing estimators
of β under the linear regression model {y,Xβ, σ2
I} is extended to the case when a given vector of parametric functions κ=Kβ is to be estimated under the general Gauss-Markov model. 相似文献