There is increasing interest in topological analysis of brain networks as complex systems, with researchers often using neuroimaging to represent the large-scale organization of nervous systems without precise cellular resolution. Here we used graph theory to investigate the neuronal connectome of the nematode worm Caenorhabditis elegans, which is defined anatomically at a cellular scale as 228...

OBJECTIVES To evaluate club drug use and its potential association with STI among female sex workers (FSWs) in China. METHODS From November 2008 to January 2009, participants were recruited at sex work venues in five cities for a questionnaire survey. Free testing for syphilis, Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (NG) was provided. Logistic regression models were used to ass...

Schizophrenia has been conceptualized as a disorder of brain connectivity. Recent studies suggest that brain connectivity may be disproportionally impaired among the so-called rich club. This small core of densely interconnected hub regions has been hypothesized to form an important infrastructure for global brain communication and integration of information across different systems of the brai...

The NP-hard 2-Club problem is, given an undirected graph G = (V,E) and ` ∈ N, to decide whether there is a vertex set S ⊆ V of size at least ` such that the induced subgraph G[S] has diameter at most two. We make progress towards a systematic classification of the complexity of 2-Club with respect to a hierarchy of prominent structural graph parameters. First, we present the following tight NP-...

BACKGROUND Talented football players are expected to overcome large training and match loads, indicating a high weekly level of physical activity (PA). AIMS With the use of accelerometers, the aim of this study was to objectively describe the players' total time spent in moderate-to-vigorous PA (MVPA), vigorous PA (VPA) and very vigorous PA (VVPA) per day in 1 week. Since high-intensity PA ha...

A kidney exchange is a centrally-administered barter market where patients swap their willing yet incompatible donors. Modern kidney exchanges use 2-cycles, 3-cycles, and chains initiated by non-directed donors (altruists who are willing to give a kidney to anyone) as the means for swapping. We propose significant generalizations to kidney exchange. We allow more than one donor to donate in exc...

In this paper, we extend Schweizer’s open club model to clubs with goods that have a semipublic nature rather than a pure public nature. We study limit core allocations, which are those allocations that remain in the core of a replicated economy. An equivalent notion for open clubs with pure public goods was Schweizer’s concept of club efficiency under a variable number of economic agents. We s...

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