Spatial structure of hierarchical groups: testing for processes of aggregation,clustering, and spatial centrality in crayfish (Orconectes rusticus)

Competing group members tend to arrange in a social order that governs who will likely submit to whom. In many species the spatial distribution of individuals often reflects social status: dominants tend to occupy central locations while subordinates are often found along the group's periphery. This article explores the emergence of spatial consequences as a result of social rank differentiation. Rather than orienting centripetally, the movements of crayfish (Orconectes rusticus) primarily indicated a tendency to remain close to arena walls. Spatial locations were affected by the location of group members; but, rather than actively aggregating or clustering, individuals maintained a minimum distance. Previously established social rank did not affect spatial distributions. High population densities in the field are likely attributed to habitat constraints, rather than any social or centripetal tendencies of individual crayfish.     

Tillering in grain sorghum over a wide range of population densities: identification of a common hierarchy for tiller emergence,leaf area development and fertility

Most studies of tiller development have not related the physiological and morphological features of each culm to its subsequent fertility. This introduces problems when trying to account for the effects of tillering on yield in crop models. The objective of this study was to detect the most likely early determinants of tiller fertility in sorghum by identifying hierarchies for emergence, fertility and grain number of tillers over a wide range of assimilate availabilities. Emergence, phenology, leaf area development and dry weight partitioning were quantified weekly for individual tillers and main culms of tillering and uniculm plants grown at one of four densities, from two to 16 plants m(-2). For a given plant in any given density, the same tiller hierarchy applied for emergence of tillers, fertility of the emerged tillers and their subsequent grain number. These results were observed over a range of tiller fertility rates (from 7 to 91%), fertile tiller number per plant at maturity (from 0.2 to 4.7), and tiller contribution to grain yield (from 5 to 78 %). Tiller emergence was most probably related to assimilate supply and light quality. Development, fertility and contribution to yield of a specific tiller were highly dependent on growing conditions at the time of tiller emergence, particularly via early leaf area development of the tiller, which affected its subsequent leaf area accumulation. Assimilate availability in the main culm at the time of tiller emergence was the most likely early determinant of subsequent tiller fertility in this study.     

酿酒葡萄品质评价及其对气象条件的响应

根据2004～2005年我国北方6省酿酒葡萄主要产区葡萄取样和宁夏芦花台园艺场田间试验葡萄化验结果,运用层次分析方法（AHP）对酿酒葡萄主要品质因子总糖、糖酸比pH、单宁进行综合评价,运用主成分分析方法和因子分析法研究影响每个地区酿酒葡萄综合品质的主要气象因子和影响时段。结果表明：2004～2005年贺兰山东麓的御马、玉泉营、广夏三基地、贺东在庄园;河西走廊的高台、武威;新疆石河子酿酒葡萄品质优良,渤海湾的烟台、蓬莱、昌藜等地酿酒葡萄品质表现一般。酿酒葡萄综合品质主要受果实着色期、全生育期和7～8月的降水量和水热系数的影响,其中降水量起主导作用。果实着色期气温日较差和全生育期平均相对湿度对酿酒葡萄综合品质的形成也有重要影响,影响相对较小的是果实着色期的最低气温。采样地区的光照、温度等气象条件基本适宜酿酒葡萄品质形成,对优质酿酒葡萄形成没有大的限制作用。     

层次分析法在大花蕙兰品种选择上的应用

运用层次分析法对大花蕙兰8个品种的株高、叶色、花色、花香、花径、花枝数、每枝花朵数、花枝长度、抗性、是否春节开花等10个性状进行综合评价。结果表明:所选品种综合性状表现优良,与生产实际基本相符,尤其是‘开心果’、‘韩国小姐’和‘欲望’3个品种,可在育种和生产上多加重视。     

THE PROBLEM OF THE FUTURE WORLD: W.E.B. DU BOIS AND THE RACE CONCEPT AT MIDCENTURY

Most studies of police–minority relations in America focus on blacks, usually in comparison with whites. This pattern is particularly puzzling in light of the growing population of Hispanic Americans throughout the US, now outnumbering blacks and consisting of the majority in some major cities. Aside from the need for more empirical research on the policing of Hispanics per se, comparing Hispanics’ relations with the police to other racial and ethnic groups offers some important insights into both the dimensions that are shared across groups and those that are distinctive to Hispanics. This article critically evaluates the small body of empirical research literature on this topic – highlighting both deficiencies in this literature as well as suggestive findings – and concludes by identifying a set of issues that should be addressed in future studies. The available evidence largely supports a racial-hierarchy perspective with regard to the policing of different racial and ethnic groups in the US.     

Partner notification methods for African American men being treated for trichomoniasis: a consideration of main men, Second Hitters, and Third Players

This pilot study sought information on African American men's preferences for partner notification methods for a common sexually transmitted infection called trichomoniasis. Two focus groups of African American men were convened at a public STI clinic where they were being treated for trichomoniasis. The groups identified a sexual hierarchy in men's preferences for methods of partner notification. The hierarchy consisted of main men (Cake Daddies), second men (Second Hitters), and third or fourth men (Third Players), with placement depending on age, income, and social status. Health department employees affirmed the existence of a sexual hierarchy in a separate focus group. Sexual and economic bartering formed the basis of the hierarchy, and the secrecy involved in such arrangements presented a considerable challenge for STI control. Disease intervention specialists who were responsible for contact tracing spoke of cat-and-mouse methods in contacting the men without understanding fully exactly how the hierarchy influenced men's responses to partner notification. The findings suggest that STI control efforts must take the sexual hierarchy and its privacy implications into account if partner notification methods are to be acceptable to African American men.