When birds of a feather flock together and when they do not: Status composition, social dominance orientation, and organizational attractiveness.

Although similarity-attraction notions suggest that similarity--for example, in terms of values, personality, and demography--attracts, the authors found that sometimes demographic similarity attracts and sometimes it repels. Consistent with social dominance theory (J. Sidanius & F. Pratto, 1999), they demonstrated in 3 studies that when prospective employees supported group-based social hierarchies (i.e., were high in social dominance orientation), those in high-status groups were attracted to demographic similarity within an organization, whereas those in low-status groups were repelled by it. An important theoretical implication of the findings is that social dominance theory and traditional similarity-attraction notions together help explain a more complex relationship between demographic similarity and attraction than was previously acknowledged in the organizational literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Making the invisible visible: Fear and disclosure of sexual orientation at work.

Stigma theory was used to examine the fears underlying the disclosure of a gay identity at work. Using a national sample of 534 gay, lesbian, and bisexual employees, this study examined the antecedents that affect the degree of disclosure of a gay identity at work and, for those who had not disclosed, the factors that influence their fears about full disclosure. Employees reported less fear and more disclosure when they worked in a group that was perceived as supportive and sharing their stigma. Perceptions of past experience with sexual orientation discrimination were related to increased fears but to greater disclosure. For those who had not fully disclosed their stigma, the fears associated with disclosure predicted job attitudes, psychological strain, work environment, and career outcomes. However, actual disclosure was unrelated to these variables. The utility of fear of disclosure for understanding processes underlying the disclosure of gay and other invisible stigmatized identities in the workplace is discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Unity through diversity: Value-in-diversity beliefs, work group diversity, and group identification.

Research on work group diversity has more or less neglected the possibility that reactions to diversity may be informed by individuals' beliefs about the value of diversity (vs. homogeneity) for their work group. We studied the role of such diversity beliefs as a moderator of the relationship between work group diversity and individuals' identification with the work group across 2 studies. Study 1 was a cross-sectional survey that focused on gender diversity and gender diversity beliefs. Study 2 was a laboratory experiment in which work group diversity and diversity beliefs were manipulated. Results of both studies support the prediction that work group diversity and group identification are more positively related the more individuals believe in the value of diversity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

First impressions: A multicultural content analysis of professional psychology program Web sites.

With the ascension of the Internet as an information resource, Web sites are likely to be the first exposure applicants have to specific programs. The authors evaluated professional psychology program Web sites for ethnic and sexual orientation minority content, discovering that diversity content of Web sites was considerably less than in previously examined paper application materials. Clinical psychology programs were more likely to state a commitment to diversity training while counseling psychology programs were more likely to state a diversity minor/track. School psychology programs had the lowest diversity content on their Web pages. This article explores how graduate psychology program Web sites communicate multicultural information and offers recommendations on using the World Wide Web as a cost-effective tool to attract a diverse student body. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of spatial and spectral resolution in estimating ecosystem α-diversity by satellite imagery

Remote sensing represents a powerful tool to derive quantitative and qualitative information about ecosystem biodiversity. In particular, since plant species richness is a fundamental indicator of biodiversity at the community and regional scales, attempts were made to predict species richness (spatial heterogeneity) by means of spectral heterogeneity. The possibility of using spectral variance of satellite images for predicting species richness is known as Spectral Variation Hypothesis. However, when using remotely sensed data, researchers are limited to specific scales of investigation. This paper aims to investigate the effects of scale (both as spatial and spectral resolution) when searching for a relation between spectral and spatial (related to plant species richness) heterogeneity, by using satellite data with different spatial and spectral resolution. Species composition was sampled within square plots of 100 m² nested in macroplots of 10,000 m². Spectral heterogeneity of each macroplot was calculated using satellite images with different spatial and spectral resolution: a Quickbird multispectral image (4 bands, spatial resolution of 3 m), an Aster multispectral image (first 9 bands used, spatial resolution of 15 m for bands 1 to 3 and 30 m for bands 4 to 9), an ortho-Landsat ETM+ multispectral image (bands 1 to 5 and band 7 used; spatial resolution, 30 m), a resampled 60 m Landsat ETM+ image.Quickbird image heterogeneity showed a statistically highly significant correlation with species richness (r = 0.69) while coarse resolution images showed contrasting results (r = 0.43, r = 0.67, and r = 0.69 considering the Aster, Landsat ETM+, and the resampled 60 m Landsat ETM+ images respectively). It should be stressed that spectral variability is scene and sensor dependent. Considering coarser spatial resolution images, in such a case even using SWIR Aster bands (i.e. the additional spectral information with respect to Quickbird image) such an image showed a very low power in catching spectral and thus spatial variability with respect to Landsat ETM+ imagery. Obviously coarser resolution data tend to have mixed pixel problems and hence less sensitive to spatial complexity. Thus, one might argue that using a finer pixel dimension should inevitably result in a higher level of detail. On the other hand, the spectral response from different land-cover features (and thus different species) in images with higher spectral resolution should exhibit higher complexity.Spectral Variation Hypothesis could be a basis for improving sampling designs and strategies for species inventory fieldwork. However, researchers must be aware on scale effects when measuring spectral (and thus spatial) heterogeneity and relating it to field data, hence considering the concept of scale not only related to a spatial framework but even to a spectral one.     

一种支持宏分集策略的软分数频率复用方法

在3GPP2 AIE的框架标准中同时要求采用频率复用和宏分集，但是现有的频率复用方法是无法支持宏分集策略的．鉴于此，在软分数频率复用方法的基础上，基于可拓集合思想，通过建立可用频段与研究区域之间的物元模型，得到了一种能够在小区边缘支持宏分集的软分数频率复用方法．研究表明该频率复用方法在有效降低小区干扰的同时提高了频率利用率，同时小区边缘用户由于小区间干扰的协调以及宏分集策略带来的增益，性能得到了较大提高．仿真结果表明该方法有效地提高了小区边缘的平均容量。     

THE THEORETICAL BER PERFORMANCE ANALYSIS OF A COOPERATIVE DIVERSITY SCHEME IN FREQUENCY SELECTIVE FADING CHANNEL

A novel cooperative diversity scheme based on Distributed Space-Time Block Coding and Multi-Carrier Code Division Multiple Access (DSTBC-MC-CDMA) is proposed which works well in frequency selective fading channels with multiple single-antenna users. And an analytical error model is established to describe the symbol decoding errors between interusers, based on which a close form expression for theoretical Bit Error Rate (BER) performance of the scheme is derived to analyze the influence of the interuser decoding errors on the BER performance of the scheme. Then simulation is complimented to verify the analytic result above, which also shows that the BER performance of DSTBC-MC-CDMA outgoes that of non-cooperative MC-CDMA with considerable gains. Further- more, the simulations coincide with the theoretical results well.     

PCR-DGGE技术及其在环境工程生物处理中的应用

阐述了PCR-DGGE技术的原理及其优点,探讨了PCR-DGGE技术在环境工程废水生物处理、废气生物处理和污泥生物处理中的应用,分析了PCR-DGGE技术用于生物处理系统中微生物群落多样性和动态性研究的现状、前景和改进的策略.     

MIMO系统中基于加权公平队列的空间复用多用户接入调度算法

多入多出(MIMO)系统利用多个发射和接收天线可以取得空间复用的效果.传统的加权公平队列WFQ虽然给每个用户提供了公平的接入信道机会,但是并没有利用MIMO系统空间复用的优点,系统容量并没有得到改善.针对这个问题,提出了一种新的基于加权公平队列的空间复用多用户接入SMMA调度算法,将上层的公平调度策略和物理层的优化天线分配相结合.最后通过仿真,将传统的WFQ算法和基于WFQ的空间复用多用户接入调度算法进行比较.仿真结果证明SMMA-WFQ算法不但给每个用户提供了公平的接入信道机会,而且提高了系统容量.     

基于似P范数FOCUSS的稀疏信号盲分离

把似P范数FOCUSS方法应用于稀疏信号盲分离中,采用k均值聚类算法来估计混合矩阵;然后利用似P范数FOCUSS方法来求解具有线性约束优化问题的稀疏源信号,从而给出了一种基于似P范数FOCUSS方法的稀疏信号盲分离算法。该算法计算量小,精度较高。仿真结果表明该算法是有效的,具有良好的分离性能。