105 research outputs found

    Climate Model for Winter Wheat Yield Simulation

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    Winter wheat yields were simlulated by a model requiring climatic data as input for estimating crop evapotranspiration and phenological development. An assumed relationship between the winter wheat yields and the amount and timing of crop water use was optimized to simulate yields for two case studies: a single season, irrigated wheat study, and a multi-year, dryland wheat study. The model explained more than 90% of the variance of wheat yields in the irrigated study where total irrigation amounts varied between 0 and 55 cm. About 40% of the variance was explained for annual yields from a 21-year, dryland winter wheat study

    On-road emissions of ammonia: An underappreciated source of atmospheric nitrogen deposition

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    We provide updated spatial distribution and inventory data for on-road NH3 emissions for the continental United States (U.S.) On-road NH3 emissions were determined from on-road CO2 emissions data and empirical NH3:CO2 vehicle emissions ratios. Emissions of NH3 from on-road sources in urbanized regions are typically 0.1– 1.3 t km−2 yr−1 while NH3 emissions in agricultural regions generally range from 0.4–5.5 t km−2 yr−1, with a few hot spots as high as 5.5–11.2 t km−2 yr−1. Counties with higher vehicle NH3 emissions than from agriculture include 40% of the U.S. population. The amount of wet inorganic N deposition as NH4+ from the National Atmospheric Deposition Program (NADP) network ranged from 37 to 83% with a mean of 58.7%. Only 4% of the NADP sites across the U.S. had \u3c45% of the N deposition as NH4+ based on data from 2014 to 2016, illustrating the near-universal elevated proportions of NH4+ in deposition across the U.S. Case studies of on-road NH3 emissions in relation to N deposition include four urban sites in Oregon and Washington where the average NH4- N:NO3-N ratio in bulk deposition was 2.3. At urban sites in the greater Los Angeles Basin, bulk deposition of NH4-N and NO3-N were equivalent, while NH4-N:NO3-N in throughfall under shrubs ranged from 0.6 to 1.7. The NH4-N:NO3-N ratio at 7–10 sites in the Lake Tahoe Basin averaged 1.4 and 1.6 in bulk deposition and throughfall, and deposition of NH4-N was strongly correlated with summertime NH3 concentrations. On-road emissions of NH3 should not be ignored as an important source of atmospheric NH3, as a major contributor to particulate air pollution, and as a driver of N deposition in urban and urban-affected regions

    Evaluating the potential for the environmentally sustainable control of foot and mouth disease in Sub-Saharan Africa

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    Strategies to control transboundary diseases have in the past generated unintended negative consequences for both the environment and local human populations. Integrating perspectives from across disciplines, including livestock, veterinary and conservation sectors, is necessary for identifying disease control strategies that optimise environmental goods and services at the wildlife-livestock interface. Prompted by the recent development of a global strategy for the control and elimination of foot-and-mouth disease (FMD), this paper seeks insight into the consequences of, and rational options for potential FMD control measures in relation to environmental, conservation and human poverty considerations in Africa. We suggest a more environmentally nuanced process of FMD control that safe-guards the integrity of wild populations and the ecosystem dynamics on which human livelihoods depend while simultaneously improving socio-economic conditions of rural people. In particular, we outline five major issues that need to be considered: 1) improved understanding of the different FMD viral strains and how they circulate between domestic and wildlife populations; 2) an appreciation for the economic value of wildlife for many African countries whose presence might preclude the country from ever achieving an FMD-free status; 3) exploring ways in which livestock production can be improved without compromising wildlife such as implementing commodity-based trading schemes; 4) introducing a participatory approach involving local farmers and the national veterinary services in the control of FMD; and 5) finally the possibility that transfrontier conservation might offer new hope of integrating decision-making at the wildlife-livestock interface

    Risk factors for late bowel and bladder toxicities in NRG Oncology prostate cancer trials of high-risk patients: A meta-analysis of physician-rated toxicities

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    Purpose: A meta-analysis of sociodemographic variables and their association with late (\u3e180 days from start of radiation therapy[RT]) bowel, bladder, and clustered bowel and bladder toxicities was conducted in patients with high-risk (clinical stages T2c-T4b or Gleason score 8-10 or prostate-specific antigen level \u3e20) prostate cancer. Methods and materials: Three NRG trials (RTOG 9202, RTOG 9413, and RTOG 9406) that accrued from 1992 to 2000 were used. Late toxicities were measured with the Radiation Therapy Oncology Group Late Radiation Morbidity Scale. After controlling for study, age, Karnofsky Performance Status, and year of accrual, sociodemographic variables were added to the model for each outcome variable of interest in a stepwise fashion using the Fine-Gray regression models with an entry criterion of 0.05. Results: A total of 2432 patients were analyzed of whom most were Caucasian (76%), had a KPS score of 90 to 100 (92%), and received whole-pelvic RT+HT (67%). Of these patients, 13 % and 16% experienced late grade ≥2 bowel and bladder toxicities, respectively, and 2% and 3% experienced late grade ≥3 bowel and bladder toxicities, respectively. Late grade ≥2 clustered bowel and bladder toxicities were seen in approximately 1% of patients and late grade ≥3 clustered toxicities were seen in 2 patients ( Conclusions: Patients with high-risk prostate cancer who receive whole-pelvic RT+LT HT are more likely to have a grade ≥2 bowel toxicity than those who receive prostate-only RT. LT bowel and bladder toxicities were infrequent. Future studies will need to confirm these findings utilizing current radiation technology and patient-reported outcomes

    Measuring Five Dimensions of Religiosity Across Adolescence

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    This paper theorizes and tests a latent variable model of adolescent religiosity in which five dimensions of religiosity are interrelated: religious beliefs, religious exclusivity, external religiosity, private practice, and religious salience. Research often theorizes overlapping and independent influences of single items or dimensions of religiosity on outcomes such as adolescent sexual behavior, but rarely operationalizes the dimensions in a measurement model accounting for their associations with each other and across time. We use longitudinal structural equation modeling (SEM) with latent variables to analyze data from two waves of the National Study of Youth and Religion. We test our hypothesized measurement model as compared to four alternate measurement models and find that our proposed model maintains superior fit. We then discuss the associations between the five dimensions of religiosity we measure and how these change over time. Our findings suggest how future research might better operationalize multiple dimensions of religiosity in studies of the influence of religion in adolescence

    Duration of Androgen Deprivation in Locally Advanced Prostate Cancer: Long-Term Update of NRG Oncology RTOG 9202

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    PurposeTrial RTOG 9202 was a phase 3 randomized trial designed to determine the optimal duration of androgen deprivation therapy (ADT) when combined with definitive radiation therapy (RT) in the treatment of locally advanced nonmetastatic adenocarcinoma of the prostate. Long-term follow-up results of this study now available are relevant to the management of this disease.Methods and materialsMen (N=1554) with adenocarcinoma of the prostate (cT2c-T4, N0-Nx) with a prostate-specific antigen (PSA) <150 ng/mL and no evidence of distant metastasis were randomized (June 1992 to April 1995) to short-term ADT (STAD: 4 months of flutamide 250 mg 3 times per day and goserelin 3.6 mg per month) and definitive RT versus long-term ADT (LTAD: STAD with definitive RT plus an additional 24 months of monthly goserelin).ResultsAmong 1520 protocol-eligible and evaluable patients, the median follow-up time for this analysis was 19.6 years. In analysis adjusted for prognostic covariates, LTAD improved disease-free survival (29% relative reduction in failure rate, P<.0001), local progression (46% relative reduction, P=.02), distant metastases (36% relative reduction, P<.0001), disease-specific survival (30% relative reduction, P=.003), and overall survival (12% relative reduction, P=.03). Other-cause mortality (non-prostate cancer) did not differ (5% relative reduction, P=.48).ConclusionsLTAD and RT is superior to STAD and RT for the treatment of locally advanced nonmetastatic adenocarcinoma of the prostate and should be considered the standard of care

    Identification and mitigation of narrow spectral artifacts that degrade searches for persistent gravitational waves in the first two observing runs of Advanced LIGO

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    Searches are under way in Advanced LIGO and Virgo data for persistent gravitational waves from continuous sources, e.g. rapidly rotating galactic neutron stars, and stochastic sources, e.g. relic gravitational waves from the Big Bang or superposition of distant astrophysical events such as mergers of black holes or neutron stars. These searches can be degraded by the presence of narrow spectral artifacts (lines) due to instrumental or environmental disturbances. We describe a variety of methods used for finding, identifying and mitigating these artifacts, illustrated with particular examples. Results are provided in the form of lists of line artifacts that can safely be treated as non-astrophysical. Such lists are used to improve the efficiencies and sensitivities of continuous and stochastic gravitational wave searches by allowing vetoes of false outliers and permitting data cleaning
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