ESTIMATING THE NUMBER OF HOMELESS: Media Misrepresentation of an Urban Problen

ABSTRACT: In the 1980s several estimates were made of the size of the homeless population nationwide. An examination of these estimates shows that claims by advocacy groups that 2–3 million persons were homeless on any night were unjustified. Instead, social scientific studies agree that the number is probably about 300,000–500,000. This discrepancy tests the ability of the media to distinguish between good social science research and mere guesstimates. An examination of US magazines and newspapers found that, as a group, the media were more likely to cite high estimates than low estimates and this changed only slightly over time. Two factors seem to explain why journalists cannot distinguish between good and bad estimates: media bias and the process whereby information is gathered.     

揭秘IT白领生存之道：巧妙用面子赚钞票

翻盖手机为什么受欢迎 你知道翻盖手机为什么在东北亚地区尤其是中国流行吗？恐怕很少有人想到,原因之一是与中国人爱面子有关系。     

WEAKENING STRONG BLACK POLITICAL EMPOWERMENT: IMPLICATIONS FROM ATLANTA'S 2009 MAYORAL ELECTION

Atlanta is perhaps the city with the greatest degree of black political empowerment (BPE) in the United States. Yet in 2009 a relatively weak white mayoral candidate nearly won the general and runoff elections over a field of stronger black candidates. Why? Treating Atlanta as a prototypical case, the article examines factors that undermine the capacity of blacks to retain control of mayoralties in strong BPE cities, with an emphasis on disruptions to black electorates, discontent among black citizens, and reinvestment in electoral politics by whites at the local level.     

NEW INTEGRATED SIMULATION TECHNIQUES FOR THE ELECTROMAGNETIC ANALYSIS OF MICROWAVE CIRCUITS USING THE TLM METHOD

A new methodology is presented which allows the integration of lumped elements into electromagnetic simulations, using the TLM method. It is shown that the new method retains the symmetrical condensed node algorithm structure, with the potential to be applied to all lumped elements. A new and accurate method for the extraction of circuit parameters from the impulse response of the TLM method is also presented. The method is simple and can be used for waveguide and planar structures. A study is carried out on the applications of various data windowing techniques during the postprocessing stages of an electromagnetic analysis. This has resulted in the realization of the need for careful selection of a particular window profile, according to the application and the nature of the required results.     

二酪氨酸层赋予酵母孢子抗氧化活性

酿酒酵母(Saccharomyces cerevisiae)孢子壁是一个多层结构,其最外层为二酪氨酸层,由酚类化合物NN′-二甲酰基二酪氨酸组成。二酪氨酸层是酵母孢子壁独有的结构,在酵母营养细胞的细胞壁中不存在。因为许多细胞酚类化合物能够清除自由基,我们猜测NN′-二甲酰基二酪氨酸可以作为一种抗氧化剂。为了研究孢子的抗氧化性,将营养细胞、野生型孢子和dit1△孢子培养在强氧化剂H_2O_2中,观察现象。本研究发现相对于酵母营养细胞,含有二酪氨酸层的野生型孢子具有抗自由基的能力使孢子具有抗氧化活性,同时二酪氨酸层缺陷型菌株dit1△孢子对自由基敏感。另外,本研究发现NN′-二甲酰基二酪氨酸能够清除自由基。因此,NN′-二甲酰基二酪氨酸可在未来用作一种新型的抗氧化材料。     

Development Aspects of an Integrated Pyroelectric Array Incorporating a Thin PZT Film and Radiation Collectors

Work is being undertaken to produce an uncooled pyroelectric infra-red detector array which incorporates within its structure, an array of radiation collectors made by the bulk micro-machining of silicon. Development aspects of the processing route are presented here.     

DIET-MEDIATED INTER-COLONIAL AGGRESSION IN THE FORMOSAN SUBTERRANEAN TERMITE <Emphasis Type="Italic">Coptotermes formosanus</Emphasis>

In most social insects, intercolonial and interspecific aggression are expressions of territoriality. In termites, cuticular hydrocarbons (CHCs) have been extensively studied for their role in nestmate recognition and aggressive discrimination of nonnest-mates. More recently, molecular genetic techniques have made it possible to determine relatedness between colonies and to investigate the influence of genetics on aggression. In the Formosan subterranean termite, Coptotermes formosanus, however, the role of CHCs and genetic relatedness in inter-colony aggression has been ambiguous, suggesting the involvement of additional factors in nest-mate recognition. In this study we assess the range of aggression in this termite species and characterize the influence of genetic relatedness, CHC profiles and diet on aggression levels. We collected four colonies of C. formosanus, feeding either on bald cypress or birch, from three locations in Louisiana. Inter-colony aggression ranged from low to high. Differences in CHC profiles, as well as genetic distances between colonies determined by using microsatellite DNA markers, showed no significant correlation with aggression. However, termite diet (host tree) played a significant role in determining the level of aggression. Thus, two distantly related colonies, each feeding on different diets, showed high aggression that significantly diminished if they were fed on the same wood in the laboratory (spruce). Using headspace solid phase microextraction, we found three compounds from workers fed on birch that were absent in workers fed on spruce. Such diet-derived chemicals may be involved in the complex determination of nest-mate recognition in C. formosanus.