44,080 research outputs found

    Topology regulates pattern formation capacity of binary cellular automata on graphs

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    We study the effect of topology variation on the dynamic behavior of a system with local update rules. We implement one-dimensional binary cellular automata on graphs with various topologies by formulating two sets of degree-dependent rules, each containing a single parameter. We observe that changes in graph topology induce transitions between different dynamic domains (Wolfram classes) without a formal change in the update rule. Along with topological variations, we study the pattern formation capacities of regular, random, small-world and scale-free graphs. Pattern formation capacity is quantified in terms of two entropy measures, which for standard cellular automata allow a qualitative distinction between the four Wolfram classes. A mean-field model explains the dynamic behavior of random graphs. Implications for our understanding of information transport through complex, network-based systems are discussed.Comment: 16 text pages, 13 figures. To be published in Physica

    Framing Ethnic Variations in Alcohol Outcomes from Biological Pathways to Neighborhood Context

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    Background Health disparities research seeks to eliminate disproportionate negative health outcomes experienced in some racial/ethnic minority groups. This brief review presents findings on factors associated with drinking and alcohol‐related problems in racial/ethnic groups. Methods Those discussed are as follows: (i) biological pathways to alcohol problems, (ii) gene × stress interactions, (iii) neighborhood disadvantage, stress, and access to alcohol, and (iv) drinking cultures and contexts. Results These factors and their interrelationships are complex, requiring a multilevel perspective. Conclusions The use of interdisciplinary teams and an epigenetic focus are suggested to move the research forward. The application of multilevel research to policy, prevention, and intervention programs may help prioritize combinations of the most promising intervention targets

    J Acad Nutr Diet

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    Obesity is generally inversely related to income among women in the United States. Less access to healthy foods is one way lower income can influence dietary behaviors and body weight. Federal food assistance programs, such as the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), are an important source of healthy food for low-income populations. In 2009, as part of a nationwide policy revision, WIC added a fruit and vegetable (F/V) voucher to WIC food packages. This quasi-experimental study determined whether F/V prices at stores authorized to accept WIC (ie, WIC vendors) decreased after the policy revision in seven Illinois counties. It also examined cross-sectional F/V price variations by store type and neighborhood characteristics. Two pre-policy observations were conducted in 2008 and 2009; one post-policy observation was conducted in 2010. Small pre- to post-policy reductions in some F/V prices were found, particularly for canned fruit and frozen vegetables at small stores. Compared with chain supermarkets, mass merchandise stores had lower prices for fresh F/V and frozen F/V and small stores and non-chain supermarkets had higher canned and frozen F/V prices, but lower fresh F/V prices. Limited price differences were found across neighborhoods, although canned vegetables were more expensive in neighborhoods with higher concentrations of either Hispanics or blacks and fresh F/V prices were lower in neighborhoods with more Hispanics. Results suggest the WIC policy revision contributed to modest reductions in F/V prices. WIC participants' purchasing power can differ depending on the type and neighborhood of the WIC vendor used.20132015-02-01T00:00:00ZP60 MD003424/MD/NIMHD NIH HHS/United StatesP50 CA106743/CA/NCI NIH HHS/United StatesP50CA106743/CA/NCI NIH HHS/United StatesP60ND003424/ND/ONDIEH CDC HHS/United StatesP30 DK092949/DK/NIDDK NIH HHS/United States24183996PMC4084875878

    Low-Cost Air Quality Monitoring Tools: From Research to Practice (A Workshop Summary).

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    In May 2017, a two-day workshop was held in Los Angeles (California, U.S.A.) to gather practitioners who work with low-cost sensors used to make air quality measurements. The community of practice included individuals from academia, industry, non-profit groups, community-based organizations, and regulatory agencies. The group gathered to share knowledge developed from a variety of pilot projects in hopes of advancing the collective knowledge about how best to use low-cost air quality sensors. Panel discussion topics included: (1) best practices for deployment and calibration of low-cost sensor systems, (2) data standardization efforts and database design, (3) advances in sensor calibration, data management, and data analysis and visualization, and (4) lessons learned from research/community partnerships to encourage purposeful use of sensors and create change/action. Panel discussions summarized knowledge advances and project successes while also highlighting the questions, unresolved issues, and technological limitations that still remain within the low-cost air quality sensor arena

    Ethnic Entrepreneurs and Collective Violence: Assessing Spatial Variations in Anti- Chinese Rioting within Jakarta during the May 1998 Riots

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    The concept of scapegoating is frequently used to explain how opportunistic elites attempt to deflect blame onto vulnerable ethnic minorities, particularly during times of social turmoil. However, the notion of scapegoating is undertheorized in the confliEthnic entrepreneurs, collective violence, scapegoating, micro-foundations of

    Representativeness of breast cancer cases in an integrated health care delivery system.

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    BackgroundIntegrated health care delivery systems, with their comprehensive and integrated electronic medical records (EMR), are well-poised to conduct research that leverages the detailed clinical data within the EMRs. However, information regarding the representativeness of these clinical populations is limited, and thus the generalizability of research findings is uncertain.MethodsUsing data from the population-based California Cancer Registry, we compared age-adjusted distributions of patient and neighborhood characteristics for three groups of breast cancer patients: 1) those diagnosed within Kaiser Permanente Northern California (KPNC), 2) non-KPNC patients from NCI-designated cancer centers, and 3) those from all other hospitals.ResultsKPNC patients represented 32 % (N = 36,109); cancer center patients represented 7 % (N = 7805); and all other hospitals represented 61 % (N = 68,330) of the total breast cancer patients from this geographic area during 1996-2009. Compared with cases from all other hospitals, KPNC had slightly fewer non-Hispanic Whites (70.6 % versus 74.4 %) but more Blacks (8.1 % versus 5.0 %), slightly more patients in the 50-69 age range and fewer in the younger and older age groups, a slightly lower proportion of in situ but higher proportion of stage I disease (41.6 % versus 38.9 %), were slightly less likely to reside in the lowest (4.2 % versus 6.5 %) and highest (36.2 % versus 39.0 %) socioeconomic status neighborhoods, and more likely to live in suburban metropolitan areas and neighborhoods with more racial/ethnic minorities. Cancer center patients differed substantially from patients from KPNC and all other hospitals on all characteristics assessed. All differences were statistically significant (p < .001).ConclusionsAlthough much of clinical research discoveries are based in academic medical centers, patients from large, integrated medical centers are likely more representative of the underlying population, providing support for the generalizability of cancer research based on electronic data from these centers

    Social Interaction and Sickness Absence

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    Is the sickness absence of an individual affected by the sickness absence behavior of the neighbors? Well-known methodological problems, in particular the so-called reflection problem, arise when trying to answer such questions about group effects. Based on data from Sweden, we adopt several different approaches to solve these problems. Regardless of the approach chosen, we obtain statistically significant estimates indicating that group effects are important for individual sickness absence behavior.Sick-pay insurance; work absence; moral hazard; reflection problem; social norms

    Social Interaction and Sickness Absence

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    Does the average level of sickness absence in a neighborhood affect individual sickness absence through social interaction on the neighborhood level? To answer this question, we consider evidence of local benefit-dependency cultures. Well-known methodological problems in this type of analysis include avoiding the so-called reflection problem and disentangling the causal effects of group behavior on individual behavior from the effects of individual sorting on neighborhoods. Based on data from Sweden, we adopt several different approaches to deal with these problems. The results are robust in the sense that regardless of approach and identifying assumptions, we obtain statistically significant estimates indicating group effects.Sick-pay Insurance; Work Absence; Moral Hazard; Social Norms
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