382 research outputs found

    Firefighter Problem Played on Infinite Graphs

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    The Firefighter Problem was introduced over 30 years ago and continues to be studied by researchers today. The problem consists of a graph of interest where a fire breaks out at time t = 0 on any given vertex of thegraph G. The player, then, gets to place a firefighter to “protect” a vertex from the fire. Each consecutive turn,the fire spreads to adjacent vertices. These vertices are then referred to as “burned”. The firefighter also gets tomove to protect an additional, unburned vertex, completing the first round. Each vertex that the firefighter “defends” stays protected for the remainder of the game. The game ends when the fire cannot move to anyadjacent vertices. This game can be used to solve real world problems. For example, we can model the spread ofdiseases in a community or the spread of a wildfire using the Firefighter Problem. There are many known resultsfor the Firefighter Problem on finite graphs. In this project, we study the Firefighter Problem on infinitegraphs, with the goal of expanding on known results. We are exploring various infinite grids by imposing the additional requirement that firefighters can only move to adjacent, unburned vertices

    Annual Report of the Superintendent of the Blind Institute

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    Pamphlet published by Alcorn & Fisher, Mississippi state printers, in 1872, containing the 1871 annual report by Sarah B. Merrill, superintendent of the State Blind Institute. The pamphlet includes the names of the pupils in 1871, their places of residence, and the causes of their blindness.https://scholarsjunction.msstate.edu/mss-williams-papers/1077/thumbnail.jp

    A State-of-the-Science Review of Arsenic's Effects on Glucose Homeostasis in Experimental Models.

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    BackgroundThe prevalence of type 2 diabetes (T2D) has more than doubled since 1980. Poor nutrition, sedentary lifestyle, and obesity are among the primary risk factors. While an estimated 70% of cases are attributed to excess adiposity, there is an increased interest in understanding the contribution of environmental agents to diabetes causation and severity. Arsenic is one of these environmental chemicals, with multiple epidemiology studies supporting its association with T2D. Despite extensive research, the molecular mechanism by which arsenic exerts its diabetogenic effects remains unclear.ObjectivesWe conducted a literature search focused on arsenite exposure in vivo and in vitro, using relevant end points to elucidate potential mechanisms of oral arsenic exposure and diabetes development.MethodsWe explored experimental results for potential mechanisms and elucidated the distinct effects that occur at high vs. low exposure. We also performed network analyses relying on publicly available data, which supported our key findings.ResultsWhile several mechanisms may be involved, our findings support that arsenite has effects on whole-body glucose homeostasis, insulin-stimulated glucose uptake, glucose-stimulated insulin secretion, hepatic glucose metabolism, and both adipose and pancreatic β-cell dysfunction.DiscussionThis review applies state-of-the-science approaches to identify the current knowledge gaps in our understanding of arsenite on diabetes development. https://doi.org/10.1289/EHP4517

    Linguistics

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    Contains research objectives and summary of research on one research project.National Institute of Mental Health (Grant 3 P01 MH13390-08S1)National Institutes of Health (Grant 5 TOl HD00111-10)National Institute of Mental Health (Grant HD 05168-01, 02, 03)M.I.T. Sloan Fund for Basic ResearchGrant Foundatio

    Oxidative Phosphorylation Impairment by DDT and DDE

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    There is increasing evidence supporting the characterization of the pesticide DDT and its metabolite, DDE, as obesogens and metabolic disruptors. Elucidating the mechanism is critical to understanding whether the association of DDT and DDE with obesity and diabetes is in fact causal. One area of research investigating the etiology of metabolic diseases is mitochondrial toxicity. Several studies have found associations between mitochondrial defects and insulin resistance, cellular respiration, substrate utilization, and energy expenditure. Although the mitotoxicity of DDT and DDE was established 20–40 years ago, it was not viewed in the light of the diseases faced today; therefore, it is prudent to reexamine the mitotoxicity literature for mechanistic support of DDT and DDE as causal contributors to obesity and diabetes, as well as associated diseases, such as cancer and Alzheimer's disease. This review aims to focus on studies investigating the effect of DDT or DDE on mammalian mitochondrial oxidative phosphorylation. We illustrate that both DDT and DDE impair the electron transport chain (ETC) and oxidative phosphorylation. We conclude that there is reasonable data to suggest that DDT and DDE target specific complexes and processes within the mitochondria, and that these insults could in turn contribute to the role of DDT and DDE in mitochondria-associated diseases

    The effectiveness of splinting as perceived by the parents of children with Juvenile Ideopathic Arthritis

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    Juvenile idiopathic arthritis (JIA) is an important disease of childhood with farreaching effects on the child and family. Splinting is a major treatment modality used by occupational therapists for children with JIA. Parents play a central role in whether, when and how splints are used with their children on a daily basis. This paper describes a qualitative research project, which was undertaken to evaluate an occupational therapy service for children with JIA whose treatment had involved splinting. Using semi-structured interviews, the study investigated five mothers' perceptions of the effectiveness of splinting for their children. The interviews revealed five major points. First, the informants generally believed the splinting to be effective. Secondly, the children involved generally resisted wearing splints because they were physically uncomfortable and made them feel different to other children. Thirdly, the mothers used a variety of strategies to ensure that their children wore the splints. Fourthly, the perception of having a positive and supportive relationship with the therapist enhanced the mothers' ability to adhere to splinting. Lastly, the mothers' grief at having a child with JIA influenced their ability to understand and attend to information about specific interventions such as splinting. Practical responses to these findings are outlined

    Simplified Models of Vector Control Impact upon Malaria Transmission by Zoophagic Mosquitoes

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    BACKGROUND\ud \ud High coverage of personal protection measures that kill mosquitoes dramatically reduce malaria transmission where vector populations depend upon human blood. However, most primary malaria vectors outside of sub-Saharan Africa can be classified as "very zoophagic," meaning they feed occasionally (<10% of blood meals) upon humans, so personal protection interventions have negligible impact upon their survival.\ud \ud METHODS AND FINDINGS\ud \ud We extended a published malaria transmission model to examine the relationship between transmission, control, and the baseline proportion of bloodmeals obtained from humans (human blood index). The lower limit of the human blood index enables derivation of simplified models for zoophagic vectors that (1) Rely on only three field-measurable parameters. (2) Predict immediate and delayed (with and without assuming reduced human infectivity, respectively) impacts of personal protection measures upon transmission. (3) Illustrate how appreciable indirect communal-level protection for non-users can be accrued through direct personal protection of users. (4) Suggest the coverage and efficacy thresholds required to attain epidemiological impact. The findings suggest that immediate, indirect, community-wide protection of users and non-users alike may linearly relate to the efficacy of a user's direct personal protection, regardless of whether that is achieved by killing or repelling mosquitoes. High protective coverage and efficacy (≥80%) are important to achieve epidemiologically meaningful impact. Non-users are indirectly protected because the two most common species of human malaria are strict anthroponoses. Therefore, the small proportion of mosquitoes that are killed or diverted while attacking humans can represent a large proportion of those actually transmitting malaria.\ud \ud CONCLUSIONS\ud \ud Simplified models of malaria transmission by very zoophagic vectors may be used by control practitioners to predict intervention impact interventions using three field-measurable parameters; the proportion of human exposure to mosquitoes occurring when an intervention can be practically used, its protective efficacy when used, and the proportion of people using it

    Impact of the national home safety equipment scheme ‘Safe At Home’ on hospital admissions for unintentional injury in children under 5: a controlled interrupted time series analysis

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    Background: Unintentional home injuries are a leading cause of preventable death in young children. Safety education and equipment provision improve home safety practices, but their impact on injuries is less clear. Between 2009 and 2011 a national home safety equipment scheme was implemented in England (Safe At Home), targeting high injury rate areas and socio-economically disadvantaged families with children under 5. This provided a ‘natural experiment’ for evaluating the scheme’s impact on hospital admissions for unintentional injuries.Methods: Controlled interrupted time series analysis of unintentional injury hospital admission rates in small areas (Lower layer Super-Output Areas (LSOAs)) in England where the scheme was implemented (intervention areas, n=9,466)) matched with LSOAs in England and Wales where it was not implemented (control areas, n=9,466), with subgroup analyses by density of equipment provision.Results: 57,656 homes receiving safety equipment were included in the analysis. In the two years after the scheme ended, monthly admission rates declined in intervention areas (-0.33% (-0.47% to -0.18%)) but did not decline in control areas (0.04% (-0.11% to 0.19%), p value for difference in trend=0.001)). Greater reductions in admission rates were seen as equipment provision density increased. Effects were not maintained beyond two years after the scheme ended.Conclusions: A national home safety equipment scheme was associated with a reduction in injury-related hospital admissions in children under 5 in the 2-years after the scheme ended. Providing a higher number of items of safety equipment appears to be more effective in reducing injury rates than providing fewer items
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