28 research outputs found

    Improved remote sensing methods to detect northern wild rice (Zizania palustris L.)

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    Declining populations of Zizania palustris L. (northern wildrice, or wildrice) during the last century drives the demand for new and innovative techniques to support monitoring of this culturally and ecologically significant crop wild relative. We trained three wildrice detection models in R and Google Earth Engine using data from annual aquatic vegetation surveys in northern Minnesota. Three di erent training datasets, varying in the definition of wildrice presence, were combined with Landsat 8 Operational Land Imager (OLI) and Sentinel-1 C-band synthetic aperture radar (SAR) imagery to map wildrice in 2015 using random forests. Spectral predictors were derived from phenologically important time periods of emergence (June–July) and peak harvest (August–September). The range of the Vertical Vertical (VV) polarization between the two time periods was consistently the top predictor. Model outputs were evaluated using both point and area-based validation (polygon). While all models performed well in the point validation with percent correctly classified ranging from 83.8% to 91.1%, we found polygon validation necessary to comprehensively assess wildrice detection accuracy. Our practical approach highlights a variety of applications that can be applied to guide field excursions and estimate the extent of occurrence at landscape scales. Further testing and validation of the methods we present may support multiyear monitoring which is foundational for the preservation of wildrice for future generations

    ICON: chronic rhinosinusitis

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    Exploring the region-level relationship between non-governmental organizations and maternal and child health in Tanzania

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    Thesis (Master's)--University of Washington, 2013Objective: To explore the region-level relationship between Tanzanian non-governmental organizations (NGOs) and four maternal and child health (MCH) outcomes - stunting, child vaccination, antenatal care (ANC) visits, and health facility delivery - at five time periods during the past twenty years. Methods: Associations between five region-level NGO covariates and MCH outcomes were modeled using cross-sectional and retrospective cohort designs. NGO, health, and additional covariates were derived from a 2010 NGO survey conducted by the Foundation for Civil Society, Demographic and Health Surveys (DHS), and government reports and published sources, respectively. Findings: Cross-sectionally, regional NGO concentration was positively associated with multiple MCH outcomes in 2010, with each increase of 1 NGO per 100,000 capita associated with a 3-6% increased likelihood of full child vaccination, attending ≥4 ANC visits, or health facility delivery. Following regions over time, NGO concentration in 2010 and 2000 were associated with change in MCH outcomes between DHS surveys, with each unit increase associated with a 3-10% reduction and 5% increase in the prevalence of stunting and attending ≥4 ANC visits, respectively. Conclusions: Both cross-sectionally on an individual-level and following regions over time, regional concentration of NGOs was consistently and statistically significantly associated with improved MCH outcomes in Tanzania, with similar but less consistent findings for NGO funding and staff concentration. Population-level analysis shows great promise in assessing long-term health impacts of NGOs. A greater understanding of robust indicators of population-level NGO influence may guide development of best practices for monitoring and evaluation of NGOs

    Are long-lasting insecticide-treated bednets and water filters cost-effective tools for delaying HIV disease progression in Kenya?

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    Background: Co-infection with malaria and other infectious diseases has been shown to increase viral load and accelerate HIV disease progression. A recent study in Kenya demonstrated that providing long-lasting insecticide-treated bednets (LLIN) and water filters (WF) to HIV-positive adults with CD4 >350 cells/mm3 significantly reduced HIV progression. Design: We conducted a cost analysis to estimate the potential net financial savings gained by delaying HIV progression and increasing the time to antiretroviral therapy (ART) eligibility through delivering LLIN and WF to 10% of HIV-positive adults with CD4 >350 cells/mm3 in Kenya. Results: Given a 3-year duration of intervention benefit, intervention unit cost of US32andpatient−yearARTcostofUS32 and patient-year ART cost of US757 (2011 US),overthelifetimeofARTpatients,inKenya,weestimatedtheinterventioncouldyieldareturnoninvestment(ROI)of11(95), over the lifetime of ART patients, in Kenya, we estimated the intervention could yield a return on investment (ROI) of 11 (95% uncertainty range [UR]: 5–23), based on a cost of about US2 million and savings in ART costs of about US26million(9526 million (95% UR: 8–50) (discounted at 3%). Our findings were subjected to a number of sensitivity analyses. Of note, deferral of time to ART eligibility could potentially result in 3,000 new HIV infections not averted by ART and thus decrease ART cost savings to US14 million, decreasing the ROI to 6. Conclusions: Provision of LLIN and WF could be a cost-saving and practical method to defer time to ART eligibility in the context of highly resource-constrained environments experiencing donor fatigue for HIV/AIDS programs

    Attenuated Endocytosis and Toxicity of a Mutant Cholera Toxin with Decreased Ability To Cluster Ganglioside GM1 Moleculesâ–¿

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    Cholera toxin (CT) moves from the plasma membrane (PM) of host cells to the endoplasmic reticulum (ER) by binding to the lipid raft ganglioside GM1. The homopentomeric B-subunit of the toxin can bind up to five GM1 molecules at once. Here, we examined the role of polyvalent binding of GM1 in CT action by producing chimeric CTs that had B-subunits with only one or two normal binding pockets for GM1. The chimeric toxins had attenuated affinity for binding to host cell PM, as expected. Nevertheless, like wild-type (wt) CT, the CT chimeras induced toxicity, fractionated with detergent-resistant membranes extracted from toxin-treated cells, displayed restricted diffusion in the plane of the PM in intact cells, and remained bound to GM1 when they were immunoprecipitated. Thus, binding normally to two or perhaps only one GM1 molecule is sufficient for association with lipid rafts in the PM and toxin action. The chimeric toxins, however, were much less potent than wt toxin, and they entered the cell by endocytosis more slowly, suggesting that clustering of GM1 molecules by the B-subunit enhances the efficiency of toxin uptake and perhaps also trafficking to the ER

    ICON: chronic rhinosinusitis

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    Chronic rhinosinusitis (CRS) is a public health problem that has a significant socio-economic impact. Moreover, the complexity of this disease due to its heterogeneous nature based on the underlying pathophysiology - leading to different disease variants - further complicates our understanding and directions for the most appropriate targeted treatment strategies. Several International/national guidelines/position papers and/or consensus documents are available that present the current knowledge and treatment strategies for CRS. Yet there are many challenges to the management of CRS especially in the case of the more severe and refractory forms of disease. Therefore, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), a collaboration between EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus (ICON) on Chronic Rhinosinusitis. The purpose of this ICON on CRS is to highlight the key common messages from the existing guidelines, the differences in recommendations as well as the gaps in our current knowledge of CRS, thus providing a concise reference. In this document we discuss the definition of the disease, its relevance, pharmacoeconomics, pathophysiology, phenotypes and endotypes, genetics and risk factors, natural history and co-morbidities as well as clinical manifestations and treatment options in both adults and children comprising pharmacotherapy, surgical interventions and more recent biological approaches. Finally, we have also highlighted the unmet needs that wait to be addressed through future researc
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