Gravitation Physics at BGPL

We report progress on a program of gravitational physics experiments using cryogenic torsion pendula undergoing large-amplitude torsion oscillation. This program includes tests of the gravitational inverse square law and of the weak equivalence principle. Here we describe our ongoing search for inverse-square-law violation at a strength down to $10^{-5}$ of standard gravity. The low-vibration environment provided by the Battelle Gravitation Physics Laboratory (BGPL) is uniquely suited to this study.Comment: To be published in The Proceedings of the Francesco Melchiorri Memorial Conference as a special issue of New Astronomy Review

Hierarchies of Predominantly Connected Communities

We consider communities whose vertices are predominantly connected, i.e., the vertices in each community are stronger connected to other community members of the same community than to vertices outside the community. Flake et al. introduced a hierarchical clustering algorithm that finds such predominantly connected communities of different coarseness depending on an input parameter. We present a simple and efficient method for constructing a clustering hierarchy according to Flake et al. that supersedes the necessity of choosing feasible parameter values and guarantees the completeness of the resulting hierarchy, i.e., the hierarchy contains all clusterings that can be constructed by the original algorithm for any parameter value. However, predominantly connected communities are not organized in a single hierarchy. Thus, we develop a framework that, after precomputing at most $2(n-1)$ maximum flows, admits a linear time construction of a clustering \C(S) of predominantly connected communities that contains a given community $S$ and is maximum in the sense that any further clustering of predominantly connected communities that also contains $S$ is hierarchically nested in \C(S). We further generalize this construction yielding a clustering with similar properties for $k$ given communities in $O(kn)$ time. This admits the analysis of a network's structure with respect to various communities in different hierarchies.Comment: to appear (WADS 2013

The Convergence of Digital-Libraries and the Peer-Review Process

Pre-print repositories have seen a significant increase in use over the past fifteen years across multiple research domains. Researchers are beginning to develop applications capable of using these repositories to assist the scientific community above and beyond the pure dissemination of information. The contribution set forth by this paper emphasizes a deconstructed publication model in which the peer-review process is mediated by an OAI-PMH peer-review service. This peer-review service uses a social-network algorithm to determine potential reviewers for a submitted manuscript and for weighting the relative influence of each participating reviewer's evaluations. This paper also suggests a set of peer-review specific metadata tags that can accompany a pre-print's existing metadata record. The combinations of these contributions provide a unique repository-centric peer-review model that fits within the widely deployed OAI-PMH framework.Comment: Journal of Information Science [in press

Neural network for quality control of submunitions produced by injection loading

Injection loading of submunitions for smart weapons is a novel automated processing technique that can benefit from adaptive process control. This paper describes how the quality of submunitions could be controlled by using a neural network code in real time. Future work is planned to demonstrate fewer rejects and pollution reduction during submunition manufacturing

School Violence and the Culture of Honor

We investigated the hypothesis that a sociocultural variable known as the culture of honor would be uniquely predictive of school-violence indicators. Controlling for demographic characteristics associated in previous studies with violent crime among adults, we found that high-school students in culture-of-honor states were significantly more likely than high-school students in non-culture-of honor states to report having brought a weapon to school in the past month. Using data aggregated over a 20-year period, we also found that culture-of honor states had more than twice as many school shootings per capita as non-culture-of-honor states. The data revealed important differences between school violence and general patterns of homicide and are consistent with the view that many acts of school violence reflect retaliatory aggression springing from intensely experienced social-identity threats.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Water wave propagation and scattering over topographical bottoms

Here I present a general formulation of water wave propagation and scattering over topographical bottoms. A simple equation is found and is compared with existing theories. As an application, the theory is extended to the case of water waves in a column with many cylindrical steps

Hyperhomocysteinemia is detrimental to pregnancy in mice and is associated with preterm birth

AbstractElevated levels of homocysteine produce detrimental effects in humans but its role in preterm birth is not known. Here we used a mouse model of hyperhomocysteinemia to examine the relevance of homocysteine to preterm birth. The mouse carries a heterozygous deletion of cystathionine β-synthase (Cbs+/−). Gestational period was monitored in wild type and Cbs+/− female mice. Mouse uterine and placental tissues, human primary trophoblast cells, and human myometrial and placental cell lines were used to determine the influence of homocysteine on expression of specific genes in vitro. The activity of BKCa channel in the myometrial cell line was monitored using the patch-clamp technique. We found that hyperhomocysteinemia had detrimental effects on pregnancy and induced preterm birth in mice. Homocysteine increased the expression of oxytocin receptor and Cox-2 as well as PGE2 production in uterus and placenta, and initiated premature uterine contraction. A Cox-2 inhibitor reversed these effects. Gpr109a, a receptor for niacin, induced Cox-2 in uterus. Homocysteine upregulated GPR109A and suppressed BKCa channel activity in human myometrial cells. Deletion of Gpr109a in Cbs+/− mice reversed premature birth. We conclude that hyperhomocysteinemia causes preterm birth in mice through upregulation of the Gpr109a/Cox-2/PGE2 axis and that pharmacological blockade of Gpr109a may have potential in prevention of preterm birth

Self-similar community structure in organisations

The formal chart of an organisation is designed to handle routine and easily anticipated problems, but unexpected situations arise which require the formation of new ties so that the corresponding extra tasks can be properly accomplished. The characterisation of the structure of such informal networks behind the formal chart is a key element for successful management. We analyse the complex e-mail network of a real organisation with about 1,700 employees and determine its community structure. Our results reveal the emergence of self-similar properties that suggest that some universal mechanism could be the underlying driving force in the formation and evolution of informal networks in organisations, as happens in other self-organised complex systems

Minority carrier lifetime in silicon photovoltaics : the effect of oxygen precipitation

Single-crystal Czochralski silicon used for photovoltaics is typically supersaturated with interstitial oxygen at temperatures just below the melting point. Oxide precipitates therefore can form during ingot cooling and cell processing, and nucleation sites are typically vacancy-rich regions. Oxygen precipitation gives rise to recombination centres, which can reduce cell efficiencies by as much as 4% (absolute). We have studied the recombination behaviour in p-type and n-type monocrystalline silicon with a range of doping levels intentionally processed to contain oxide precipitates with a range of densities, sizes and morphologies. We analyse injection-dependent minority carrier lifetime measurements to give a full parameterisation of the recombination activity in terms of Shockley–Read–Hall statistics. We intentionally contaminate specimens with iron, and show recombination activity arises from iron segregated to oxide precipitates and surrounding defects. We find that phosphorus diffusion gettering reduces the recombination activity of the precipitates to some extent. We also find that bulk iron is preferentially gettered to the phosphorus diffused layer rather than to oxide precipitates

Progress towards malaria control targets in relation to national malaria programme funding

Background: Malaria control has been dramatically scaled up the past decade, mainly thanks to increasing international donor financing since 2003. This study assessed progress up to 2010 towards global malaria impact targets, in relation to Global Fund, other donor and domestic malaria programme financing over 2003 to 2009. Methods. Assessments used domestic malaria financing reported by national programmes, and Global Fund/OECD data on donor financing for 90 endemic low- and middle-income countries, WHO estimates of households owning one or more insecticide-treated mosquito net (ITN) for countries in sub-Saharan Africa, and WHO-estimated malaria case incidence and deaths in countries outside sub-Saharan Africa. Results: Global Fund and other donor funding is concentrated in a subset of the highest endemic African countries. Outside Africa, donor funding is concentrated in those countries with highest malaria mortality and case incidence rates over the years 2000 to 2003. ITN coverage in 2010 in Africa, and declines in case and death rates per person at risk over 2004 to 2010 outside Africa, were greatest in countries with highest donor funding per person at risk, and smallest in countries with lowest donor malaria funding per person at risk. Outside Africa, all-source malaria programme funding over 2003 to 2009 per case averted ($56-5,749) or per death averted ($58,000-3,900,000) over 2004 to 2010 tended to be lower (more favourable) in countries with higher donor malaria funding per person at risk. Conclusions: Increases in malaria programme funding are associated with accelerated progress towards malaria control targets. Associations between programme funding per person at risk and ITN coverage increases and declines in case and death rates suggest opportunities to maximize the impact of donor funding, by strategic re-allocation to countries with highest continued need