2,401 research outputs found

    Where are the veterinarian shortage areas anyway?

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    This paper describes an econometric model to evaluate factors associated with a county’s likelihood of being designated as a private practice shortage area under the United States' Veterinary Medicine Loan Repayment Program (VMLRP). Study determinants of equilibrium food animal veterinarian location choices were also evaluated and used as a benchmark to assess the shortage designation process. On the whole the program appears to perform quite well. For several states, however, VMLRP shortage designations are inconsistent with the model of food animal veterinarian shortages. Comparative shortage is generally more severe in states that have no VMLRP designated private practice shortage counties than in states that do.economic externalities, food animal veterinarians, loan repayment program, Agricultural and Food Policy, Livestock Production/Industries,

    Indigenous Suicide in New Zealand

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    This article describes patterns of suicide and attempted suicide among the indigenous (Ma ̄ori) population of New Zealand using official data from the New Zealand Health Information Service (NZHIS). The majority of Ma ̄ori suicides (75%) occurr in young people aged \u3c35 years. Rates of suicide are higher among Ma ̄ori males and females aged \u3c25 than in their non-Ma ̄ori peers. Rates of hospitalization for attempted suicides are higher amongst Ma ̄ori males aged 15–24, compared to non-Ma ̄ori. In contrast, suicide is virtually unknown amongst older Ma ̄ori (60 years). This article reviews explanations for the observed rates of suicide in Ma ̄ori, and examines approaches to effective intervention to reduce rates of suicide in young Ma ̄ori

    Cultural views of life phases.

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    The knowledge base in the study of human development is built primarily from work with children from the modern, global, post-industrial population. This population is unrepresentative in many respects, not least in that childhood and adolescence is dominated by the experience of formal schooling—an experience missing from the lives of most of the world’s children until very recently. This entry will examine child development from the perspective of pre-modern societies as described in the ethnographic, archaeological and historic records. Specifically, we will review material indicative of cultural or indigenous models of development, phases and phase transitions, in particular

    Interactions between carbon and nitrogen dynamics in estimating net primary productivity for potential vegetation in North America

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    We use the terrestrial ecosystem model (TEM), a process-based model, to investigate how interactions between carbon (C) and nitrogen (N) dynamics affect predictions of net primary productivity (NPP) for potential vegetation in North America. Data on pool sizes and fluxes of C and N from intensively studied field sites are used to calibrate the model for each of 17 non-wetland vegetation types. We use information on climate, soils, and vegetation to make estimates for each of 11,299 non-wetland, 0.5° latitude × 0.5° longitude, grid cells in North America. The potential annual NPP and net N mineralization (NETNMIN) of North America are estimated to be 7.032 × 1015 g C yr−1 and 104.6 × 1012 g N yr−1, respectively. Both NPP and NETNMIN increase along gradients of increasing temperature and moisture in northern and temperate regions of the continent, respectively. Nitrogen limitation of productivity is weak in tropical forests, increasingly stronger in temperate and boreal forests, and very strong in tundra ecosystems. The degree to which productivity is limited by the availability of N also varies within ecosystems. Thus spatial resolution in estimating exchanges of C between the atmosphere and the terrestrial biosphere is improved by modeling the linkage between C and N dynamics. We also perform a factorial experiment with TEM on temperate mixed forest in North America to evaluate the importance of considering interactions between C and N dynamics in the response of NPP to an elevated temperature of 2°C. With the C cycle uncoupled from the N cycle, NPP decreases primarily because of higher plant respiration. However, with the C and N cycles coupled, NPP increases because productivity that is due to increased N availability more than offsets the higher costs of plant respiration. Thus, to investigate how global change will affect biosphere-atmosphere interactions, process-based models need to consider linkages between the C and N cycles

    Prevalence and Trends in Transmitted and Acquired Antiretroviral Drug Resistance, Washington, DC, 1999-2014.

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    Background Drug resistance limits options for antiretroviral therapy (ART) and results in poorer health outcomes among HIV-infected persons. We sought to characterize resistance patterns and to identify predictors of resistance in Washington, DC. Methods We analyzed resistance in the DC Cohort, a longitudinal study of HIV-infected persons in care in Washington, DC. We measured cumulative drug resistance (CDR) among participants with any genotype between 1999 and 2014 (n = 3411), transmitted drug resistance (TDR) in ART-naïve persons (n = 1503), and acquired drug resistance (ADR) in persons with genotypes before and after ART initiation (n = 309). Using logistic regression, we assessed associations between patient characteristics and transmitted resistance to any antiretroviral. Results Prevalence of TDR was 20.5%, of ADR 40.5%, and of CDR 45.1% in the respective analysis groups. From 2004 to 2013, TDR prevalence decreased for nucleoside and nucleotide analogue reverse transcriptase inhibitors (15.0 to 5.5%; p = 0.0003) and increased for integrase strand transfer inhibitors (INSTIs) (0.0–1.4%; p = 0.04). In multivariable analysis, TDR was not associated with age, race/ethnicity, HIV risk group, or years from HIV diagnosis. Conclusions In this urban cohort of HIV-infected persons, almost half of participants tested had evidence of CDR; and resistance to INSTIs was increasing. If this trend continues, inclusion of the integrase-encoding region in baseline genotype testing should be strongly considered

    Functional, morphologic, and molecular characterization of cold storage injury

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    ObjectiveCold storage is used to preserve tissue for later transplantation. There is particular interest in prolonging cold storage time for transplantation purposes. To date, the mechanisms that contribute to vascular dysfunction in response to cold storage are poorly understood. The present study aims to characterize cold storage injury of blood vessels on functional and molecular levels.MethodsTo assess vessel function of mouse aorta, isometric force measurements were performed in a Mulvany myograph after cold storage at 4°C for various intervals. Morphologic changes were judged by histologic analysis of aortic cross-sections. To characterize cold storage-induced alterations on RNA levels, microarray analysis with subsequent polymerase chain reaction analysis was performed.ResultsCold storage for 2 days revealed significant impairment of vessel function with respect to potassium-induced vessel tone development and acetylcholine-induced vessel relaxation. Detailed analysis of acetylcholine-mediated vascular response using specific pharmacologic blockers revealed that calcium-activated potassium channels seem to be impaired after 2 days of cold storage. At this point, no severe histologic changes (eg, elastic fiber disruption) were visible. RNA expression of 24 genes was significantly changed due to cold storage even after 2 hours. These include genes associated with vessel tone development (prostaglandin E3 receptor), cardiovascular function (adiponectin), electron transport chain (uncoupling protein 1), or calcium signaling (protein kinase A regulatory subunit 2b).ConclusionsLong-term cold storage impairs vascular function, especially with respect to potassium signaling by calcium-dependent potassium channels. Microarray analysis confirmed impairment of pathways that are involved in calcium signaling and vascular function. Furthermore, various genes were significantly altered even after 2 hours, significantly before functional impairment was observed.Clinical RelevanceIn bypass surgery, vessels are stored ex situ for <2 hours and for vessel banking for up to 48 hours during decontamination before cryopreservation. We investigated the onset of storage-induced alterations. The experiments reveal various genes were altered significantly, even within the first 2 hours of cold storage. This is of major importance, because of the time delay between regulation of messenger RNA and protein level and functional consequences. The alterations described here on the molecular level occur before any alterations on morphologic or functional levels are obvious. These molecular alterations, however, may affect later graft function

    University Leadership for Innovation in Global Health and HIV/AIDS Diagnostics

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    Medical products used in the developed world often fail to adequately serve resource-limited settings where electricity, transportation and health care workers are not readily available. We suggest that the problem is not only a lack of coordinated financial resources to purchase existing medical products, but also a lack of products that are specifically designed for resource-limited settings. While donor organisations with a focus on global health are increasingly willing to bear the additional financial risk for the research and development of such high-impact medical products, corporations are still reluctant to take their best scientists and engineers away from more commercially attractive projects. Universities, on the other hand, given their teaching and research missions, are well positioned to engage in such high-risk development projects. A group of biomedical, engineering, business and social science researchers at Northwestern University (NU) propose a creative model to address significant social and health needs. The team's initial product focus is a rapid test for diagnosing infants with HIV. The NU model aligns the incentives and expertise of industry, donors and academia to innovate medical products, such as the infant HIV diagnostic test, for resource-limited settings

    Potential net primary productivity in South America: application of a global model

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    We use a mechanistically based ecosystem simulation model to describe and analyze the spatial and temporal patterns of terrestrial net primary productivity (NPP) in South America. The Terrestrial Ecosystem Model (TEM) is designed to predict major carbon and nitrogen fluxes and pool sizes in terrestrial ecosystems at continental to global scales. Information from intensively studies field sites is used in combination with continental—scale information on climate, soils, and vegetation to estimate NPP in each of 5888 non—wetland, 0.5° latitude °0.5° longitude grid cells in South America, at monthly time steps. Preliminary analyses are presented for the scenario of natural vegetation throughout the continent, as a prelude to evaluating human impacts on terrestrial NPP. The potential annual NPP of South America is estimated to be 12.5 Pg/yr of carbon (26.3 Pg/yr of organic matter) in a non—wetland area of 17.0 ° 106 km2. More than 50% of this production occurs in the tropical and subtropical evergreen forest region. Six independent model runs, each based on an independently derived set of model parameters, generated mean annual NPP estimates for the tropical evergreen forest region ranging from 900 to 1510 g°m—2°yr—1 of carbon, with an overall mean of 1170 g°m—2°yr—1. Coefficients of variation in estimated annual NPP averaged 20% for any specific location in the evergreen forests, which is probably within the confidence limits of extant NPP measurements. Predicted rates of mean annual NPP in other types of vegetation ranged from 95 g°m—2°yr—1 in arid shrublands to 930 g°m@?yr—1 in savannas, and were within the ranges measured in empirical studies. The spatial distribution of predicted NPP was directly compared with estimates made using the Miami mode of Lieth (1975). Overall, TEM predictions were °10% lower than those of the Miami model, but the two models agreed closely on the spatial patterns of NPP in south America. Unlike previous models, however, TEM estimates NPP monthly, allowing for the evaluation of seasonal phenomena. This is an important step toward integration of ecosystem models with remotely sensed information, global climate models, and atmospheric transport models, all of which are evaluated at comparable spatial and temporal scales. Seasonal patterns of NPP in South America are correlated with moisture availability in most vegetation types, but are strongly influenced by seasonal differences in cloudiness in the tropical evergreen forests. On an annual basis, moisture availability was the factor that was correlated most strongly with annual NPP in South America, but differences were again observed among vegetation types. These results allow for the investigation and analysis of climatic controls over NPP at continental scales, within and among vegetation types, and within years. Further model validation is needed. Nevertheless, the ability to investigate NPP—environment interactions with a high spatial and temporal resolution at continental scales should prove useful if not essential for rigorous analysis of the potential effects of global climate changes on terrestrial ecosystems
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