Viscous Decoupling Transitions for Individually Dragged Particles in Systems with Quenched Disorder

We show that when an individual particle is dragged through an assembly of other particles in the presence of quenched disorder, a viscous decoupling transition occurs between the dragged particle and the surrounding particles which is controlled by the quenched disorder. A counterintuitive consequence of this transition is that the velocity of the dragged particle can be increased by increasing the strength or density of the quenched disorder. The decoupling transition can also occur when the external drive on the dragged particle is increased, and is observable as a clear signature in the velocity-force response.Comment: 4 pages, 3 postscript figure

Role of transport performance on neuron cell morphology

The compartmental model is a basic tool for studying signal propagation in neurons, and, if the model parameters are adequately defined, it can also be of help in the study of electrical or fluid transport. Here we show that the input resistance, in different networks which simulate the passive properties of neurons, is the result of an interplay between the relevant conductances, morphology and size. These results suggest that neurons must grow in such a way that facilitates the current flow. We propose that power consumption is an important factor by which neurons attain their final morphological appearance.Comment: 9 pages with 3 figures, submitted to Neuroscience Letter

Adaptive mesh refinement approach to construction of initial data for black hole collisions

The initial data for black hole collisions is constructed using a conformal-imaging approach and a new adaptive mesh refinement technique, a fully threaded tree (FTT). We developed a second-order accurate approach to the solution of the constraint equations on a non-uniformly refined high resolution Cartesian mesh including second-order accurate treatment of boundary conditions at the black hole throats. Results of test computations show convergence of the solution as the numerical resolution is increased. FTT-based mesh refinement reduces the required memory and computer time by several orders of magnitude compared to a uniform grid. This opens up the possibility of using Cartesian meshes for very high resolution simulations of black hole collisions.Comment: 13 pages, 11 figure

The role of the global cryosphere in the fate of organic contaminants

The cryosphere is an important component of global organic contaminant cycles. Snow is an efficient scavenger of atmospheric organic pollutants while a seasonal snowpack, sea ice, glaciers and ice caps are contaminant reservoirs on time scales ranging from days to millennia. Important physical and chemical processes occurring in the various cryospheric compartments impact contaminant cycling and fate. A variety of interactions and feedbacks also occur within the cryospheric system, most of which are susceptible to perturbations due to climate change. In this article, we review the current state of knowledge regarding the transport and processing of organic contaminants in the global cryosphere with an emphasis on the role of a changing climate. Given the complexity of contaminant interactions with the cryosphere and limitations on resources and research capacity, interdisciplinary research and extended collaborations are essential to close identified knowledge gaps and to improve our understanding of contaminant fate under a changing climate

The influence of cognitive-perceptual variables on patterns of change over time in rural midlife and older women’s healthy eating

Although studies demonstrate that dietary interventions for healthy adults can result in beneficial dietary changes, few studies examine when and how people change in response to these interventions, particularly in rural populations. The purpose of this study was to examine patterns of change over time in healthy eating behaviors in midlife and older women in response to a one-year health-promoting intervention, and to examine what predictors (perceived benefits, barriers, self-efficacy, and family support for healthy eating) influence the changes during the intervention and follow-up. Data for this secondary analysis were from the Wellness for Women community-based trial. Women (N = 225) between the ages of 50–69 in rural Nebraska, U.S.A., were recruited. A repeated-measures experimental design was used with randomization of two rural counties to intervention (tailored newsletter) or comparison (standard newsletter) groups. Eating behavior was measured by the Healthy Eating Index. The predictor variables were assessed using standard measures. Data analysis was done using latent growth curve modeling. The tailored newsletter group was successful in improving their healthy eating behavior compared to the standard newsletter group during the one-year intervention, at the end of the intervention, and during the follow-up phase. Family support at the end of the intervention was positively associated with healthy eating at the end of the intervention. Perceived barriers had the strongest impact on healthy eating behavior at all time points. Compared to participants in the standard newsletter group, those in the tailored newsletter group perceived more family support and fewer barriers for healthy eating at the end of the intervention (mediation effects). Based on these findings, both family support and perceived barriers should be central components of interventions focused on healthy eating behavior in rural midlife and older women. Highlights ► Reducing barriers to healthy eating via the tailored newsletters was the primary factor that improved eating behavior. ► The tailored newsletters also helped women in this group garner more family support which was related to healthier eating. ► Key components of healthy eating interventions in rural older women should focus on family support and perceived barriers. ► Findings support the cultural belief that rural women rely on their families to assist with health-promoting behaviors

The influence of cognitive-perceptual variables on patterns of change over time in rural midlife and older women\u27s healthy eating.

Although studies demonstrate that dietary interventions for healthy adults can result in beneficial dietary changes, few studies examine when and how people change in response to these interventions, particularly in rural populations. The purpose of this study was to examine patterns of change over time in healthy eating behaviors in midlife and older women in response to a one-year health-promoting intervention, and to examine what predictors (perceived benefits, barriers, self-efficacy, and family support for healthy eating) influence the changes during the intervention and follow-up. Data for this secondary analysis were from the Wellness for Women community-based trial. Women (N = 225) between the ages of 50-69 in rural Nebraska, U.S.A., were recruited. A repeated-measures experimental design was used with randomization of two rural counties to intervention (tailored newsletter) or comparison (standard newsletter) groups. Eating behavior was measured by the Healthy Eating Index. The predictor variables were assessed using standard measures. Data analysis was done using latent growth curve modeling. The tailored newsletter group was successful in improving their healthy eating behavior compared to the standard newsletter group during the one-year intervention, at the end of the intervention, and during the follow-up phase. Family support at the end of the intervention was positively associated with healthy eating at the end of the intervention. Perceived barriers had the strongest impact on healthy eating behavior at all time points. Compared to participants in the standard newsletter group, those in the tailored newsletter group perceived more family support and fewer barriers for healthy eating at the end of the intervention (mediation effects). Based on these findings, both family support and perceived barriers should be central components of interventions focused on healthy eating behavior in rural midlife and older women

The influence of cognitive-perceptual variables on patterns of change over time in rural midlife and older women\u27s healthy eating

Although studies demonstrate that dietary interventions for healthy adults can result in beneficial dietary changes, few studies examine when and how people change in response to these interventions, particularly in rural populations. The purpose of this study was to examine patterns of change over time in healthy eating behaviors in midlife and older women in response to a one-year health-promoting intervention, and to examine what predictors (perceived benefits, barriers, self-efficacy, and family support for healthy eating) influence the changes during the intervention and follow-up. Data for this secondary analysis were from the Wellness for Women community-based trial. Women (N ¼ 225) between the ages of 50e69 in rural Nebraska, U.S.A., were recruited. A repeated-measures experimental design was used with randomization of two rural counties to intervention (tailored newsletter) or comparison (standard newsletter) groups. Eating behavior was measured by the Healthy Eating Index. The predictor variables were assessed using standard measures. Data analysis was done using latent growth curve modeling. The tailored newsletter group was successful in improving their healthy eating behavior compared to the standard newsletter group during the one-year intervention, at the end of the intervention, and during the follow-up phase. Family support at the end of the intervention was positively associated with healthy eating at the end of the intervention. Perceived barriers had the strongest impact on healthy eating behavior at all time points. Compared to participants in the standard newsletter group, those in the tailored newsletter group perceived more family support and fewer barriers for healthy eating at the end of the intervention (mediation effects). Based on these findings, both family support and perceived barriers should be central components of interventions focused on healthy eating behavior in rural midlife and older women

Quenched QCD at finite density

Simulations of quenched $QCD$ at relatively small but {\it nonzero} chemical potential $\mu$ on $32 \times 16^3$ lattices indicate that the nucleon screening mass decreases linearly as $\mu$ increases predicting a critical chemical potential of one third the nucleon mass, $m_N/3$, by extrapolation. The meson spectrum does not change as $\mu$ increases over the same range, from zero to $m_\pi/2$. Past studies of quenched lattice QCD have suggested that there is phase transition at $\mu = m_\pi/2$. We provide alternative explanations for these results, and find a number of technical reasons why standard lattice simulation techniques suffer from greatly enhanced fluctuations and finite size effects for $\mu$ ranging from $m_\pi/2$ to $m_N/3$. We find evidence for such problems in our simulations, and suggest that they can be surmounted by improved measurement techniques.Comment: 23 pages, Revte