Pursuit on a Graph Using Partial Information

The optimal control of a "blind" pursuer searching for an evader moving on a road network and heading at a known speed toward a set of goal vertices is considered. To aid the "blind" pursuer, certain roads in the network have been instrumented with Unattended Ground Sensors (UGSs) that detect the evader's passage. When the pursuer arrives at an instrumented node, the UGS therein informs the pursuer if and when the evader visited the node. The pursuer's motion is not restricted to the road network. In addition, the pursuer can choose to wait/loiter for an arbitrary time at any UGS location/node. At time 0, the evader passes by an entry node on his way towards one of the exit nodes. The pursuer also arrives at this entry node after some delay and is thus informed about the presence of the intruder/evader in the network, whereupon the chase is on - the pursuer is tasked with capturing the evader. Because the pursuer is "blind", capture entails the pursuer and evader being collocated at an UGS location. If this happens, the UGS is triggered and this information is instantaneously relayed to the pursuer, thereby enabling capture. On the other hand, if the evader reaches one of the exit nodes without being captured, he is deemed to have escaped. We provide an algorithm that computes the maximum initial delay at the entry node for which capture is guaranteed. The algorithm also returns the corresponding optimal pursuit policy

Phenotypic Expression in the Paper Wasp \u3ci\u3ePolistes Fuscatus\u3c/i\u3e (Hymenoptera: Vespidae)

Quantification of color/color pattern in Polistes fuscatus (Fabricius) revealed that these attributes were the interaction of two antagonistic color sequences; their expression being highly correlated with nest microclimate (relative humidity-temperature). Color/ color pattern expressions were modified under experimental conditions to produce forms having natural counterparts in the field. Principal coordinates analyses and trend surface analyses using specimens collected throughout the United States indicated three color pattern trends, representing three distinct geographic areas, and, when objectively defined, without intergradation between and/or among areas. It was concluded that fuscatus should not be considered a widespread, polytypic species; rather, as three discrete species: an eastern, P. fuscatus (Fabricius); a western, P. aurifer Saussure; and an undescribed yellow form from the southwestern United States

How can malaria rapid diagnostic tests achieve their potential? A qualitative study of a trial at health facilities in Ghana.

BACKGROUND: Rapid diagnostic tests (RDTs) for malaria are at the early stages of introduction across malaria endemic countries. This is central to efforts to decrease malaria overdiagnosis and the consequent overuse of valuable anti-malarials and underdiagnosis of alternative causes of fever. Evidence of the effect of introducing RDTs on the overprescription of anti-malarials is mixed. A recent trial in rural health facilities in Ghana reduced overprescription of anti-malarials, but found that 45.5% patients who tested negative with RDTs were still prescribed an anti-malarial. METHODS: A qualitative study of this trial was conducted, using in-depth interviews with a purposive sample of health workers involved in the trial, ranging from those who continued to prescribe anti-malarials to most patients with negative RDT results to those who largely restricted anti-malarials to patients with positive RDT results. Interviews explored the experiences of using RDTs and their results amongst trial participants. RESULTS: Meanings of RDTs were constructed by health workers through participation with the tests themselves as well as through interactions with colleagues, patients and the research team. These different modes of participation with the tests and their results led to a change in practice for some health workers, and reinforced existing practice for others. Many of the characteristics of RDTs were found to be inherently conducive to change, but the limited support from purveyors, lack of system antecedents for change and limited system readiness for change were apparent in the analysis. CONCLUSIONS: When introduced with a limited supporting package, RDTs were variously interpreted and used, reflecting how health workers had learnt how to use RDT results through participation. To build confidence of health workers in the face of negative RDT results, a supporting package should include local preparation for the innovation; unambiguous guidelines; training in alternative causes of disease; regular support for health workers to meet as communities of practice; interventions that address negotiation of health worker-patient relationships and encourage self-reflection of practice; feedback systems for results of quality control of RDTs; feedback systems of the results of their practice with RDTs; and RDT augmentation such as a technical and/or clinical troubleshooting resource

Water exchange at a hydrated platinum electrode is rare and collective

We use molecular dynamics simulations to study the exchange kinetics of water molecules at a model metal electrode surface -- exchange between water molecules in the bulk liquid and water molecules bound to the metal. This process is a rare event, with a mean residence time of a bound water of about 40 ns for the model we consider. With analysis borrowed from the techniques of rare-event sampling, we show how this exchange or desorption is controlled by (1) reorganization of the hydrogen bond network within the adlayer of bound water molecules, and by (2) interfacial density fluctuations of the bulk liquid adjacent to the adlayer. We define collective coordinates that describe the desorption mechanism. Spatial and temporal correlations associated with a single event extend over nanometers and tens of picoseconds.Comment: 10 pages, 9 figure

Monte Carlo calculations of high energy nucleon meson cascades and applications to galactic cosmic ray transport

Results obtained using a recently developed calculational method for determining the nucleon-meson cascade induced in thick materials by high-energy nucleons and charged pions are presented. The calculational method uses the intranuclear-cascade-evaporation model to treat nonelastic collisions by particles with energies approximately or smaller than GeV and an extrapolation model at higher energies. The following configurations are considered: (1) 19.2-GeV/c protons incident on iron; (2) 30.3-GeV/c protons incident on iron; (3) solar and galactic protons incident on the moon, and (4) galactic protons incident on tissue. For the first three configurations, experimental results are available and comparisons between the experimental and calculated results are given

Letter from O. K. Chandler to Representative Burdick Regarding Harold Ickes and the US Bureau of Indian Affairs, undated

This letter, undated, from O. K. Chandler, National Chairman on Organization for the American Indian Federation to United States (US) Representative Usher L. Burdick, appears to consist of a partial report on a recent conference of the American Indian Federation, with personal note from Chandler to Burdick regarding US Secretary of the Interior Harold Ickes and the US Bureau of Indian Affairs.https://commons.und.edu/burdick-papers/1558/thumbnail.jp

Is Physical Activity Effective In Reducing The Gastrointestinal Symptoms Associated with Irritable Bowel Syndrome?

OBJECTIVE: The objective of this selective EBM review is to determine whether or not physical activity is effective in reducing the gastrointestinal symptoms associated with irritable bowel syndrome in adults 18 years of age and older. STUDY DESIGN: Review of three English language primary randomized controlled trials from peer reviewed journals published between 2008-2015. DATA SOURCES: Three randomized controlled trials were found using PubMed and Cochrane. OUTCOMES MEASURED: All three studies measured irritable bowel syndrome (IBS) gastrointestinal symptom severity using self-reported questionnaires including the irritable bowel syndrome severity scoring system (IBS-SSS) and the Birmingham IBS Symptom Questionnaire. RESULTS: Kavuri et al. found that a remedial yoga module significantly improved the gastrointestinal symptoms in adult patients with IBS when compared to the wait-list control group. Although Johannesson et al. reported improvements in IBS symptoms in the physical activity group when compared to the control group, the results were not significant. Daley et al. reported significant improvement in the constipation symptoms of IBS in the physical activity group when compared to control, but no other significant differences in symptoms scores were noted. CONCLUSIONS: Based on the results of these three trials, it seems that there is a benefit to increasing physical activity in IBS patients. It is likely that physical activity can help alleviate IBS symptom severity, but further studies should be conducted to better explore these improvements

The order-disorder transition in model lipid bilayers is a first-order hexatic to liquid phase transition

We characterize the order-disorder transition in a model lipid bilayer using molecular dynamics simulations. We find that the ordered phase is hexatic. In particular, in-plane structures possess a finite concentration of 5-7 disclination pairs that diffuse throughout the plane of the bilayer, and further, in-plane structures exhibit long-range orientational order and short-range translational order. In contrast, the disordered phase is liquid. The transition between the two phases is first order. Specifically, it exhibits hysteresis, and coexistence exhibits an interface with capillary scaling. The location of the interface and its spatial fluctuations are analyzed with a spatial field constructed from a rotational-invariant for local 6-fold orientational order. As a result of finite interfacial tension, there necessarily exist associated forces of assembly between membrane-bound solutes that pre-melt the ordered phase.Comment: Addressed the comments from colleagues, corrected typos, clarified text, updated references. The new draft also contains new results relating to the hexatic phas

Total Joint Implant Alloy Oxide Layer Cell-Induced Damage

Cobalt-Chromium alloy is commonly used in total joint arthroplasty (TJA). Several studies have investigated evidence of inflammatory-cell-induced-corrosion (ICIC) causing pitting in TJA retrieved implants. Others have determined that placing orthopedic alloys into lower pH solutions will increase the rate of corrosion. We have determined that electrochemical potential and corrosion rates of human knee synovial fluid show a variation greater than an order of magnitude. This means there is going to be a significant variation between a patient’s local environment of the TJA implant and may affect how macrophages interact with alloy oxide layers. Knee disability can be quantified by using the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOSJR). In order to determine predictive measures of patient outcomes, we plan to measure the electrochemical properties of patient implants and associate them with these KOOSJR scores. In addition, we plan to further investigate the effects and extent of macrophage-mediated damage to alloys when under inflammatory conditions. The current results are inconclusive, but suggest that there is a relationship between these parameters and patient outcomes and encourage further investigation of the mechanisms at play

The asymmetrical anthropocene: resilience and the limits of posthumanism

In this article we critique resilience’s oft-celebrated overcoming of modern liberal frameworks. We bring work on resilience in geography and cognate fields into conversation with explorations of the ‘asymmetrical Anthropocene’, an emerging body of thought which emphasizes human-nonhuman relational asymmetry. Despite their resonances, there has been little engagement between these two responses to the human/world binary. This is important for changing the terms of the policy debate: engaging resilience through the asymmetrical Anthropocene framing shines a different light upon policy discourses of adaptative management, locating resilience as a continuation of modernity’s anthropocentric will-to-govern. From this vantage point, resilience is problematic, neglecting the powers of nonhuman worlds that are not accessible or appropriable for governmental use. However, this is not necessarily grounds for pessimism. To conclude, we argue that human political agency is even more vital in an indeterminate world