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Interactions between invaders and resource availability may explain variation in their success or management efficacy. For widespread invaders, regional variation in plant response to nutrients can reflect phenotypic plasticity of the invader, genetic structure of invading populations, or a combination of the two. The wetland weed Alternanthera philoxeroides (alligatorweed) is established throughout the southeastern United States and California and has high genetic diversity despite primarily spreading clonally. Despite its history in the United States, the role of genetic variation for invasion and management success is only now being uncovered. To better understand how nutrients and genotype may influence A. philoxeroides invasion, we measured the response of plants from 26 A. philoxeroides populations (three cp haplotypes) to combinations of nitrogen (4 or 200 mg/L N) and phosphorus (0.4 or 40 mg/L P). We measured productivity (biomass accumulation and allocation), plant architecture (stem diameter and thickness, branching intensity), and foliar traits (toughness, dry matter content, percent N, and percent P). A short‐term developmental assay was also conducted by feeding a subset of plants from the nutrient experiment to the biological control agent Agasicles hygrophila, to determine whether increased availability of N or P to its host influenced agent performance, as has been previously suggested. Alternanthera philoxeroides haplotype Ap1 was more plastic than other haplotypes in response to nutrient amendments, producing more than double the biomass from low to high N and 50%–68% higher shoot: root ratio than other haplotypes in the high N treatment. Alternanthera philoxeroides haplotypes differed in seven of 10 variables in response to increased N. We found no differences in short‐term A. hygrophila development between haplotypes but mass was 23% greater in high than low N treatments. This study is the first to explore the interplay between nutrient availability, genetic variation, and phenotypic plasticity in invasive characteristics of the global invader, A. philoxeroides. [ABSTRACT FROM AUTHOR]

Aim: Introduced species may display or foster novel latitudinal clines because they are not well adapted to their new habitats. We tested the hypothesis that the latitudinal cline in nematode diversity in salt marshes would differ between the native (United States) and introduced (China) ranges of Spartina alterniflora. Location: East Coasts of the United States (30.32–43.33°N) and China (30.36–39.14°N). Methods: We extracted nematodes from soil samples collected at 32 sites along the United States East Coast and 41 sites along the Chinese coast. We compared latitudinal patterns in nematode diversity and composition between the native and introduced ranges. Results: In the native range of S. alterniflora, nematode richness at lower latitudes was almost twice as high as that at higher latitudes. In contrast, we found no latitudinal pattern in nematode richness or diversity in the introduced range of S. alterniflora. Nematode genus richness at all sites in China was about half that at lower latitudes in the United States. Beta diversity of nematodes increased with geographic distance in the United States, but not China. Main conclusions: Nematode diversity did not show latitudinal clines in salt marshes dominated by introduced S. alterniflora in China. A likely explanation is that the recently introduced populations are still relatively genetically homogenous, whereas in the native range, genetic variation in plant populations across latitude drives different nematode communities. We suggest that future studies of introduced species will gain additional insights by taking an explicitly geographic perspective. [ABSTRACT FROM AUTHOR]

Recent research in medicine and public health highlights differences in health related to race, ethnicity, socioeconomic status, and gender. These inequalities, often labeled "disparities," are pervasive and pertain to the major causes of morbidity, mortality, and lost life years. Often ignored in discussions of health disparities is the complex role of work, including not only occupational exposures and working conditions, but also benefits associated with work, effects of work on families and communities, and policies that determine where and how people work. The authors argue that work should be considered explicitly as a determinant of health disparities. Their conceptual model and empirical evidence, built on previous contributions, describe how work contributes to disparities in health on multiple levels. The examples focus on the United States, but many of the key conceptual features can also be applied to other countries. The model emphasizes behaviors and characteristics of institutions rather than individual workers. This approach avoids a focus on individual responsibility alone, which may lead to victim blaming and failure to emphasize policies and institutional factors that affect large populations and systematically create and maintain racial, gender, and socioeconomic disparities in health. [ABSTRACT FROM AUTHOR]

The article examines the thesis that African Americans are effectively excluded from the decision making process in the community level. The study focuses on a research of black powerlessness in Chicago that evaluates the extent to which Blacks are excluded from positions of influence in major institutional sectors. Their findings indicated that Negroes occupied only 2.6 percent of the top making policy-making decisions in the Chicago area. Black representation in Chicago was greatest in the elected public sector, welfare and religious voluntary organization and industrial unions. There was a virtual absence of Black representation in the policy-making positions of the private institutions such as business corporations, banks, insurance companies and universities. The research tests the hypothesis by examining the degree to which Blacks are found in key policy-making positions in the Milwaukee and Wisconsin metropolitan areas. A total of 4.930 policy-making positions in the business, public government ,academic and voluntary sectors were identified including the number of blacks holding the policy-making positions.

The purpose of the present study was to examine the relationships between the ecological distribution of heroin addiction in San Antonio, Texas, and measures of socio-economic status and minority group status. [ABSTRACT FROM AUTHOR]