Evaluating the rank generating function of a graphic 2-polymatroid

We consider the complexity of the two-variable rank generating function, $S$, of a graphic 2-polymatroid. For a graph $G$, $S$ is the generating function for the number of subsets of edges of $G$ having a particular size and incident with a particular number of vertices of $G$. We show that for any $x,y \in \mathbb{Q}$ with $xy \not = 1$, it is $\#$P-hard to evaluate $S$ at $(x,y)$. We also consider the $k$-thickening of a graph and computing $S$ for the $k$-thickening of a graph

Recommendations for Using Online Social Networking Technologies to Reduce Inaccurate Online Health Information

This short report highlights patients' increasing use of the Internet and online social networking technologies to seek health information, and the consequences of gaining information from sites with biased or inaccurate health information. Reflecting on the utility of online social networking technologies for reaching large audiences, practical advice is listed for how health providers can use these technologies to improve the quality of health information that patients receive over the Internet. We recommend that health providers use online social networking technologies to communicate with patients and health information consumers and direct them to reputable sources with accurate health information. We outline the steps to this approach

SOPHIA

The Iraqi Insurgency (2003–2011) has commonly been characterized as demonstrating the tendency for violence to cluster and diffuse at the local level. Recent research has demonstrated that insurgent attacks in Iraq cluster in time and space in a manner similar to that observed for the spread of a disease. The current study employs a variety of approaches common to the scientific study of criminal activities to advance our understanding of the correlates of observed patterns of the incidence and contagion of insurgent attacks. We hypothesize that the precise patterns will vary from one place to another, but that more attacks will occur in areas that are heavily populated, where coalition forces are active, and along road networks. To test these hypotheses, we use a fishnet to build a geographical model of Baghdad that disaggregates the city into more than 3000 grid cell locations. A number of logistic regression models with spatial and temporal lags are employed to explore patterns of local escalation and diffusion. These models demonstrate the validity of arguments under each of three models but suggest, overall, that risk heterogeneity arguments provide the most compelling and consistent account of the location of insurgency. In particular, the results demonstrate that violence is most likely at locations with greater population levels, higher density of roads, and military garrisons

Demonstration that a lectin-like receptor (gp90MEL) directly mediates adhesion of lymphocytes to high endothelial venules of lymph nodes.

Lymphocyte migration from the blood into most secondary lymphoid organs is initiated by a highly selective adhesive interaction with the endothelium of specialized blood vessels known as high endothelial venules (HEV). The propensity of lymphocytes to migrate to particular lymphoid organs is known as lymphocyte homing, and the receptors on lymphocytes that dictate interactions with HEV at particular anatomical sites are designated "homing receptors". Based upon antibody blockade experiments and cell-type distribution studies, a prominent candidate for the peripheral lymph node homing receptor in mouse is the approximately 90-kD cell surface glycoprotein (gp90MEL) recognized by the monoclonal antibody MEL-14. Previous work, including sequencing of a cDNA encoding for this molecule, supports the possibility that gp90MEL is a calcium-dependent lectin-like receptor. Here, we show that immunoaffinity-purified gp90MEL interacts in a sugar-inhibitable manner with sites on peripheral lymph node HEV and prevents attachment of lymphocytes. Lymphocyte attachment to HEV in Peyer's patches, a gut-associated lymphoid organ, is not affected by gp90MEL. The results demonstrate that gp90MEL, as a lectin-like receptor, directly bridges lymphocytes to the endothelium

Examining the Relationship Between Road Structure and Burglary Risk Via Quantitative Network Analysis

OBJECTIVES: To test the hypothesis that the spatial distribution of residential burglary is shaped by the configuration of the street network, as predicted by, for example, crime pattern theory. In particular, the study examines whether burglary risk is higher on street segments with higher usage potential. METHODS: Residential burglary data for Birmingham (UK) are examined at the street segment level using a hierarchical linear model. Estimates of the usage of street segments are derived from the graph theoretical metric of betweenness, which measures how frequently segments feature in the shortest paths (those most likely to be used) through the network. Several variants of betweenness are considered. The geometry of street segments is also incorporated—via a measure of their linearity—as are several socio-demographic factors. RESULTS: As anticipated by theory, the measure of betweenness was found to be a highly-significant predictor of the burglary victimization count at the street segment level for all but one of the variants considered. The non-significant result was found for the most localized measure of betweenness considered. More linear streets were generally found to be at lower risk of victimization. CONCLUSIONS: Betweenness offers a more granular and objective means of measuring the street network than categorical classifications previously used, and its meaning links more directly to theory. The results provide support for crime pattern theory, suggesting a higher risk of burglary for streets with more potential usage. The apparent negative effect of linearity suggests the need for further research into the visual component of target choice, and the role of guardianship

Effects of synchronous music on 400-metre sprint performance

The aim of the present study was to assess the effects of motivating and oudeterous (neither motivating nor demotivating) synchronous music on 400-m sprint performance while controlling for the potential confound of pre-performance mood. A panel of volunteer Caucasian males ( n = 20; mean age = 20.5 years, s = 1.2) rated the motivational qualities of 32 musical selections using the Brunel Music Rating Inventory-2. An experimental group of volunteer Caucasian males ( n = 36; mean age = 20.4 years, s = 1.4) completed three 400-m time trials under conditions of motivational music, oudeterous music, and a no-music control. Pre-performance mood was assessed using the Brunel University Mood Scale (BRUMS). A series of repeated-measures analyses of variance with Bonferroni adjustment revealed no differences in the BRUMS subscales. A repeated-measures analysis of variance on the 400-m times showed a significant effect ( F 1.24, 42.19 = 10.54, P 2 = 0.24) and follow-up pair wise comparisons revealed differences between the synchronous music conditions and the control condition. This finding supported the first research hypothesis, that synchronous music would result in better performance than a no-music control, but not the second hypothesis, that performance in the motivational synchronous music condition would be better than that in the oudeterous condition. It appears that synchronous music can be applied to anaerobic endurance performance among non-elite sportspersons with a considerable positive effect

The complexity of two graph orientation problems

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierWe consider two orientation problems in a graph, namely the minimization of the sum of all the shortest path lengths and the minimization of the diameter. Our main result is that for each positive integer k, there is a linear-time algorithm that decides for a planar graph Gwhether there is an orientation for which the diameter is at most k. We also extend this result from planar graphs to any minor-closed family F not containing all apex graphs. In contrast, it is known to be NP-complete to decide whether a graph has an orientation such that the sum of all the shortest path lengths is at most an integer specified in the input. We give a simpler proof of this result.This work is partially supported by EC Marie Curie programme NET-ACE (MEST-CT-2004-6724), and Heilbronn Institute for Mathematical Research, Bristol

Identification and purification of an endogenous receptor for the lectin pallidin from Polysphondylium pallidum.

We report the identification and purification of an endogenous carbohydrate-containing receptor of pallidin, the cell surface lectin implicated in mediating cell-cell adhesion in the cellular slime mold Polysphondylium pallidum. The receptor is identified in an aqueous extract of crude P. pallidum membranes as a potent inhibitor of the hemagglutination activity of pallidin. The inhibitor is purified to apparent homogeneity by affinity precipitation with pallidin followed by fractionation of the solubilized precipitate on Sepharose 4B. The hemagglutination inhibitor (HAI) is metabolically radiolabeled, indicating that it is a biosynthetic product of the amoebae and not an ingested food substance. The HAI is released into the extracellular medium by living, differentiated amoebae. This release is markedly facilitated by the addition of D-galactose, a specific saccharide that binds to pallidin. Hence, the HAI appears to have an in situ association with pallidin at the cell surface. Exogenously added HAI promotes the agglutination of differentiated amoebae in a gyrated suspension at very low concentrations. The results are consistent with a model of cell-cell adhesion in which the HAI is a multivalent, extracellular aggregation factor that is recognized by pallidin molecules on adjacent cells. The HAI would then be analogues to the aggregation factors identified in marine sponges

The equivalence of two graph polynomials and a symmetric function

The U-polynomial, the polychromate and the symmetric function generalization of the Tutte polynomial due to Stanley are known to be equivalent in the sense that the coefficients of any one of them can be obtained as a function of the coefficients of any other. The definition of each of these functions suggests a natural way in which to strengthen them which also captures Tutte's universal V-function as a specialization. We show that the equivalence remains true for the strong functions thus answering a question raised by Dominic Welsh

Minimization of Illness Absenteeism in Primary School Students Using Low-Cost Hygiene Interventions

Objective: Safe water and hygiene intervention was evaluated to assess its impact on students’ health, hygiene practices and reduction in illness absenteeism in primary school students. Method: After evaluatingprimary schools of Amravati district; 50 students with high enteric illness absenteeism were selected for study. Families with problem of in-house water contamination were provided earthen pot with tap for water storage and soap for hand washing at school and home. Household drinking waters (before and after intervention) were analyzed for potability. Results: By adopting correct water storage (water container with tap), handling and hand washing practices found to improve health and reduction in 20% illness absenteeism in school. Promoting these interventions and improvement in water-behavioral practices prevented in-house-water contamination. Conclusion: These low cost intervention (water storage container with tap) promises to reducing school absenteeism by minimizing risk of transmission of enteric infections by promoting water and student hygiene