47 research outputs found

    Identifying ENSO Phase Impacts on Area Yield Insurance Rates: An Application of Non-Parametric Analysis

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    The paper reports results of non-parametric analysis of peanut, corn, and cotton yield distributions by the ElNino Southern Oscillation (ENSO) phases in the Southeastern U.S. For validation purposes, the historical yield data is complemented by a set of simulated peanut yields generated using daily weather data. The hypothesis, justified by the observed South-Eastern climate differences and research on ENSO cycles and planting dates, is that different climate conditions during ENSO cycles translate into different yield distributions and, therefore, insurance premiums (loss to coverage ratios). Kernel density estimates of historical county yield data show consistent patterns in the actuarially fair rate schedules grouped by ENSO phases and geographical areas. In particular, corn and cotton yield insurance premiums appear to be the most dependent on the ENSO phases and are the highest, regardless of coverage, during ElNino and the lowest during LaNina. Peanut premiums are higher during Neutral years and lowest during LaNina. The results appear to be robust to the transformations used to make the yield series stationary. While these dependencies do not necessarily correspond to the precipitation and solar radiation characteristics of the corresponding ENSO cycles in the Southeastern US, drawing direct analogies with yield variability is premature as many less documented factors, like the spacing of sunny and rainy days, may be just as important. The comparisons of the empirical and simulated peanut yield distributions show that they are similar in many ways and that the dissimilarities can be explained by known factors. These findings should be more relevant for the area yield insurance as opposed to the APH arrangements as the yield data used in designing contracts for the former reflects the systemic risk more influenced by climate than by the farm-level, basis risk factors accommodated in the APH plans.Risk and Uncertainty, Q140, C220, G220,

    The Role of Water Stress in Creating Spatial Yield Variability in Soybeans

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    Recent advancements in yield monitors and global positioning systems that can create spatial yield maps has generated much excitement and controversy among farmers and researchers. Site-specific field management promises to maximize field level net return and minimize environmental impact by managing fields using spatially variable management practices. The success of site-specific field management depends upon discovery of relationships between environment, management, and resulting yield variability, and ultimately, how these relationships can be exploited to compute optimum prescriptions. Farmers are faced with trying to determine how to manage variability to improve profits. Researchers are trying to develop methods to analyze causes of yield variability, and determine how to develop prescriptions for fertility, and cultural practices to capitalize on variability across field. While environmental, management, soil, and pest factors have been studied for many years, researchers are just beginning to determine how these factors vary across fields, contributing to spatial yield variability

    Non-Parametric Analysis of ENSO Impacts on Yield Distributions: Implications for GRP Contract Design

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    The paper reports preliminary results of non-parametric analysis of historical and crop model generated peanut yield series in the Southwest Georgia. The results suggest ENSO phase dependent differences in yield distributions that are similar for both the simulated and actual series. The differences are magnified in GRP insurance premiums.Crop Production/Industries,

    Characterization of Soybean Yield Variability Using Crop Growth Models and 13C Discrimination

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    During the past several years, crop models have successfully been used to test the hypothesis that water stress is the primary factor that causes spatial yield variability in soybean [Glycine max (L.) Merr.] fields. However, there have been few attempts to validate this hypothesis through direct temporal and spatial measurements of water stress during the season. Recently, a technique has been developed to relate plant tissue 13C levels to the temporal water stress experienced by soybean plants. The purpose of this work was to compare the spatial yield loss simulated by a crop model with yield loss measured by 13C discrimination (∆) for a soybean field in South Dakota. The field was divided into 0.9-ha grids and the CROPGRO-Soybean model was calibrated to minimize error between simulated and observed yield in each grid over two seasons (1998, 2000). 13C discrimination was measured at 50 points representing 23 of the grids used in the crop modeling analysis in 2000. Simulated yield loss in grids that encompassed each 13C point in 2000 were compared to measurements of yield loss using the 13C discrimination technique. Initially, the root mean square error and r2 between simulated and measured yield loss was 259 kg ha-1 and 0.24, respectively. Upon closer inspection, it was observed that yield in 5 grids with the highest error likely were influenced by processes that are not represented in the crop model. Removing these values dramatically improved the agreement between simulated and observed yield loss, giving an RMSE of 216 kg ha-1 and r2 of 0.81. Both 13C discrimination and simulation results indicated that substantial yield loss occurred due to water stress in the summit/backslope areas of the field

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    Remote Sensing and Geospatial Technological Applications for Site-specific Management of Fruit and Nut Crops: A Review

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    Abstract: Site-specific crop management (SSCM) is one facet of precision agriculture which is helping increase production with minimal input. It has enhanced the cost-benefit scenario in crop production. Even though the SSCM is very widely used in row crop agriculture like corn, wheat, rice, soybean, etc. it has very little application in cash crops like fruit and nut. The main goal of this review paper was to conduct a comprehensive review of advanced technologies, including geospatial technologies, used in site-specific management of fruit and nut crops. The review explores various remote sensing data from different platforms like satellite, LIDAR, aerial, and field imaging. The study analyzes the use of satellite sensors, such as Quickbird, Landsat, SPOT, and IRS imagery as well as hyperspectral narrow-band remote sensing data in study of fruit and nut crops in blueberry, citrus, peach, apple, etc. The study also explores other geospatial technologies such as GPS, GIS spatial modeling, advanced image processing techniques, and information technology for suitability study, orchard delineation, and classification accuracy assessment. The study also provides an example of a geospatial model developed in ArcGIS ModelBuilder to automate the blueberry production suitability analysis. The GI

    Identifying ENSO Phase Impacts on Area Yield Insurance Rates: An Application of Non-Parametric Analysis

    No full text
    The paper reports results of non-parametric analysis of peanut, corn, and cotton yield distributions by the ElNino Southern Oscillation (ENSO) phases in the Southeastern U.S. For validation purposes, the historical yield data is complemented by a set of simulated peanut yields generated using daily weather data. The hypothesis, justified by the observed South-Eastern climate differences and research on ENSO cycles and planting dates, is that different climate conditions during ENSO cycles translate into different yield distributions and, therefore, insurance premiums (loss to coverage ratios). Kernel density estimates of historical county yield data show consistent patterns in the actuarially fair rate schedules grouped by ENSO phases and geographical areas. In particular, corn and cotton yield insurance premiums appear to be the most dependent on the ENSO phases and are the highest, regardless of coverage, during ElNino and the lowest during LaNina. Peanut premiums are higher during Neutral years and lowest during LaNina. The results appear to be robust to the transformations used to make the yield series stationary. While these dependencies do not necessarily correspond to the precipitation and solar radiation characteristics of the corresponding ENSO cycles in the Southeastern US, drawing direct analogies with yield variability is premature as many less documented factors, like the spacing of sunny and rainy days, may be just as important. The comparisons of the empirical and simulated peanut yield distributions show that they are similar in many ways and that the dissimilarities can be explained by known factors. These findings should be more relevant for the area yield insurance as opposed to the APH arrangements as the yield data used in designing contracts for the former reflects the systemic risk more influenced by climate than by the farm-level, basis risk factors accommodated in the APH plans
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