University of Massachusetts Boston

About: University of Massachusetts Boston is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Health care. The organization has 6541 authors who have published 12918 publications receiving 411731 citations. The organization is also known as: UMass Boston.

Linguistic and cultural barriers to care.

Abstract: CONTEXT: Primarily because of immigration, Asian Americans are one of the fastest growing and most ethnically diverse minority groups in the United States. However, little is known about their perspectives on health care quality.

A major biopolymeric component to dissolved organic carbon in surface sea water

Abstract: Organic carbon dissolved in sea water is an important component of the global carbon cycle1. Concentrations of dissolved organic carbon (DOC) in the ocean's surface mixed layer are at least twice those in the deep sea2,3, because of the production of soluble carbon compounds by marine algae in the euphotic zone4,5. But very little is known about the chemical composition of DOC, and the connection between photosynthetic production and DOC accumulation is not well understood6,7. Here we report the chemical characterization of macromolecular DOC at several sites in the Atlantic and Pacific oceans. Neutral sugars, acetate and lipids show similar distributions, suggesting that these constituents are linked together in a common macromolecular structure. Chemical linkage patterns between the oligosaccharide portions of dissolved organic matter subjected to ultrafiltration are highly specific, with little variation between ocean basins. We show that laboratory culture experiments on the decomposition of algal exudate produce macromolecular organic matter with similar compositions and linkage characteristics. We propose that a significant fraction of DOC in sea surface water consists of structurally related and biosynthetically derived acyl oligosaccharides that persist after more labile organic matter has been degraded.

Attack Robustness and Centrality of Complex Networks

Abstract: Many complex systems can be described by networks, in which the constituent components are represented by vertices and the connections between the components are represented by edges between the corresponding vertices. A fundamental issue concerning complex networked systems is the robustness of the overall system to the failure of its constituent parts. Since the degree to which a networked system continues to function, as its component parts are degraded, typically depends on the integrity of the underlying network, the question of system robustness can be addressed by analyzing how the network structure changes as vertices are removed. Previous work has considered how the structure of complex networks change as vertices are removed uniformly at random, in decreasing order of their degree, or in decreasing order of their betweenness centrality. Here we extend these studies by investigating the effect on network structure of targeting vertices for removal based on a wider range of non-local measures of potential importance than simply degree or betweenness. We consider the effect of such targeted vertex removal on model networks with different degree distributions, clustering coefficients and assortativity coefficients, and for a variety of empirical networks.

Influence of Arabidopsis thaliana accessions on rhizobacterial communities and natural variation in root exudates

Abstract: Plant species is considered to be one of the most important factors in shaping rhizobacterial communities, but specific plant-microbe interactions in the rhizosphere are still not fully understood. Arabidopsis thaliana, for which a large number of naturally occurring ecotype accessions exist, lacks mycorrhizal associations and is hence an ideal model for rhizobacterial studies. Eight Arabidopsis accessions were found to exert a marked selective influence on bacteria associated with their roots, as determined by terminal-restriction fragment length polymorphism (T-RFLP) and ribosomal intergenic spacer analysis (RISA). Community differences in species composition and relative abundance were both significant (P <0.001). The eight distinct and reproducible accession-dependent community profiles also differed from control bulk soil. Root exudates of these variants were analysed by high performance liquid chromatography (HPLC) to try to establish whether the unique rhizobacterial assemblages among accessions could be attributed to plant-regulated chemical changes in the rhizosphere. Natural variation in root exudation patterns was clearly exhibited, suggesting that differences in exudation patterns among accessions could be influencing bacterial assemblages. Other factors such as root system architecture are also probably involved. Finally, to investigate the Arabidopsis rhizosphere further, the phylogenetic diversity of rhizobacteria from accession Cvi-0 is described.

The Emergence of a Standards Market: Multiplicity of Sustainability Standards in the Global Coffee Industry

Abstract: The growing number of voluntary standards for governing transnational arenas is presenting standards organizations with a problem. While claiming that they are pursuing shared, overarching objectives, at the same time they are promoting their own respective standards that are increasingly similar. By developing the notion of ‘standards markets’, this paper examines this tension and studies how different social movement and industry-driven standards organizations compete as well as collaborate over governance in transnational arenas. Based on an in-depth case study of sustainability standards in the global coffee industry, we find that the ongoing co-existence of multiple standards is being promoted by the interplay between two countervailing mechanisms: convergence and differentiation. In conjunction, these mechanisms are enabling the emergence and persistence of a market for standards through what we describe as meta-standardization of sustainable practices. Meta-standardization leads to convergence at t...