1,227 research outputs found

    Hydrologic modeling and climate change study in the Upper Mississippi River Basin using SWAT

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    This dissertation describes the modeling efforts on the Upper Mississippi River Basin (UMRB) using the Soil and Water Assessment Tool (SWAT) model. The main goal of this study is to apply the SWAT model to the UMRB to evaluate the model as a tool for agricultural policy analysis and climate change impact analysis. A sensitivity analysis using influence coefficient method was conducted for eight selected hydrologic input parameters to identify the most to the least sensitive parameters. Calibration and validation of SWAT were performed for the Maquoketa River Watershed for streamflow on annual and monthly basis. The model was then validated for the entire UMRB streamflow and evaluated for a climate change impact analysis. The results indicate that the UMRB hydrology is very sensitive to potential future climate changes.;The impact of future climate change was then explored for the streamflow by using two 10-year scenario periods (1990s and 2040s) generated by introducing a regional climate model (RegCM2) to dynamically downscale global model (HadCM2) results. The combined GCM-RCM-SWAT model system produced an increase in future scenario climate precipitation of 21% with a resulting 50% increase in total water yield in the UMRB. Furthermore, evaluation of model-introduced uncertainties due to use of SWAT, GCM, and RCM models yielded the highest percentage bias (18%) for the GCM down scaling error.;Building upon the above SWAT validation, a SWAT modeling framework was constructed for the entire UMRB, which incorporates more detailed input data and is designed to assess the effects of land use, climate, and soil conditions on streamflow and water quality. An application of SWAT is presented for the Iowa and Des Moines River watersheds within the modeling framework constructed for the UMRB. A scenario run where conservation tillage adoption increased to 100% found a small sediment reduction of 5.8% for Iowa River Watershed and 5.7% for Des Moines River Watershed. On per-acre basis, sediment reduction for Iowa and Des Moines River Watersheds was found to be 1.86 and 1.18 metric tons respectively. Furthermore an attempt to validate the model for the entire UMRB yielded strong annual results

    Level of watershed subdivision for water quality modeling

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    The size and number of subwatersheds can impact a watershed modeling process and subsequent results. The objective of this study was to determine the appropriate level of subwatershed division for simulating flow, sediment, and nutrient. The SWAT model with GIS interface (AVSWAT) was applied to four Iowa watersheds that varied greatly in drainage area. Annual output was analyzed from each simulation, which was executed for 31 years using climatic data representing the period of 1970 to 2000. It was found that the streamflow is not significantly affected by decrease in subwatershed scale, whereas sediment yields were directly related to subwatershed scale. The threshold subwatershed size, i.e. minimum size of a subwatershed at which variation due to different subdivisions tends to stabilize, was found to be around 3 percent of the total drainage area to adequately predict sediment yield. Decreasing the size of subwatersheds beyond this level does not significantly affect the computed sediment yield. Similar analysis on nitrate concentration found 2 percent of the total drainage area as threshold area. This threshold subwatershed size can be used to optimize SWAT input data preparation requirements and simplify the interpretation of results, without compromising simulation accuracy

    Femoral head diameters in Nepalese patients undergoing hemiarthroplasty

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    Background: Sizing of the femoral head is important for determining the appropriate size of implants to be used for a patient undergoing hip arthroplasty. The present study aimed to determine the mean diameter of femoral head in Nepalese population who underwent hemiarthroplasty in our department.Methods: We retrospectively reviewed the medical records of patients who underwent hemiarthroplasty from December 2016 till December 2020. We included patients aged more than 50 years who underwent hemiarthroplasty. The diameter of the femoral head was measured intraoperatively using standard fully circular templates. For radiological measurements, X-ray of pelvis with hips anteroposterior view were included.Results: A total of 600 femoral heads were evaluated, 400 of women and 200 of men. Of these cases, the femoral head diameter were evaluated based on x-ray pelvis in 500 cases and rest of the 100 cases were evaluated intraoperatively. The mean age of the patients in our sample was 75.2±9.4 (range 50–90) years. Overall, the mean femoral head diameter (with intact articular cartilage) was 44.9±3.2 (range 39–53 mm) mm. Among the male patients, mean femoral head diameter was 47.7±2.8 mm, which was found to be significantly higher than that of female patients, who had a mean femoral head diameter of 43.7±2.4 mm, p value <0.05.Conclusions: Further studies are needed in other geographical locations, so that reference values could be established for specific regions

    Pediatric long bone fractures treated by elastic intramedullary nailing

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    Background: Pediatric long bone fractures can have a high morbidity and long term disability among the survivors. The present study was aimed to study the clinical outcomes of children with long bone fractures managed by elastic intramedullary nail.Methods: We retrospectively reviewed the medical records of children (aged 2 to 15 years) who were admitted and treated for unilateral femoral, tibial or forearm fractures with elastic intramedullary nail from January 2018 till February 2020. All were managed with elastic intramedullary nailing. The union times and complications were noted from the medical records.Results: Femoral, tibial and forearm bones were involved in 15 patients each (33.3%). Road traffic accident was reported by 31%) and physical abuse by one case (2%). The mean time of union was 10 weeks, ranging from 6 to 12 weeks. The mean time for union of the femur and tibia was 11.54 and 11.34 weeks respectively. It was significantly lower for forearm (6.67 weeks, p value <0.05). Two patients reported of bursitis and impingement, which were resolved after nail removal. One case had limb length discrepancy of about 0.5 cm in femur fracture, which was not impairing functional activity. Functional status was assessed based on Flynn criteria was found to be excellent in 36%, good in 44% and fair in 20%.Conclusions: The results of the present study show that titanium elastic nail (TEN) is an effective treatment modality for managing pediatric long bone fractures. We recommend the use of TEN in managing long bone fractures in children

    Evaluation of efficacy and safety of oral olmesartan + chlorthalidone combination in the management of hypertension in Indian patients

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    Background: Hypertension is a major health problem in India. Being a multifactorial condition often requires the administration of multiple drugs. Despite improvements in the management of hypertension and the availability of effective antihypertensive agents, only 50% of these individuals achieve BP control. The present study was undertaken to evaluate the efficacy and safety of, fixed dose combination of olmesartan 40 mg + chlorthalidone 12.5 mg, in the management of hypertension uncontrolled with olmesartan monotherapy.Methods: 110 patients were enrolled in this Post-Marketing Surveillance (PMS) study. Patients were prescribed to take fixed dose combination for 60 days.Results: There was significant decrease (P 60 years and <60 years achieved the Joint National Committee (JNC VIII) recommended goal respectively. (<150/90 for elder patients aged above 60 year and 140/90 for those aged less than 60 years).Conclusion: Thus fixed dose combination therapy of olmesartan & chlorthalidone has been shown to be excellent in efficacy and tolerability & gives another option for the optimal management of hypertension.

    Optical and electrochemical dual channel sensing of Cu2 + using functionalized furo[2,3-d]pyrimidines-2,4[1H,3H]-diones

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    Owing to their easy accessibility and high degree of structural and functional diversity, many multicomponent reactions (MCRs) have been a rich source of conjugate π-systems, functionalised chromophores (or fluorophore) and redox active molecules. Despite their high explorative potential and practical benefits, only a few MCR products have been so far investigated for their metal sensing abilities. In the present report, two furopyrimidinones (FPys) based molecular systems have been synthesized by [4 + 1] cycloaddition based MCR sequence. Designed chemosensors displayed optic (absorption spectra) as well as electroanalytical (ion selective electrode) response toward Cu2 + ion in solution and membrane phase respectively (dual channel sensing). Different aspects of both the sensing phenomena such as selectivity, association constants, detection limit, membrane composition etc. were studied in detail using UV–Vis spectroscopy, NMR titration and cell assembly. Both the compounds showed excellent performance characteristics such as high selectivity, acceptable affinity and low detection limits (10− 7 M) in both sensing assays with potential utility in the area of sample monitoring

    A new CDF model for data movement based on SRM

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    Being a large international collaboration established well before the full development of the Grid as the main computing tool for High Energy Physics, CDF has recently changed and improved its computing model, decentralizing some parts of it in order to be able to exploit the rising number of distributed resources available nowadays. Despite those efforts, while the large majority of CDF Monte Carlo production has moved to the Grid, data processing is still mainly performed in dedicated farms hosted at FNAL, requiring a centralized management of data and Monte Carlo samples needed for physics analysis. This rises the question on how to manage the transfer of produced Monte Carlo samples from remote Grid sites to FNAL in an efficient way; up to now CDF has relied on a non scalable centralized solution based on dedicated data servers accessed through rcp protocol, which has proven to be unsatisfactory. A new data transfer model has been designed that uses SRMs as local caches for remote Monte Carlo production sites, interfaces them with SAM, the experiment data catalog, and finally realizes the file movement exploiting the features provided by the data catalog transfer layer. We describe here the model and its integration within the current CDF computing architecture

    Cytokinin and abiotic stress tolerance -What has been accomplished and the way forward?

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    More than a half-century has passed since it was discovered that phytohormone cytokinin (CK) is essential to drive cytokinesis and proliferation in plant tissue culture. Thereafter, cytokinin has emerged as the primary regulator of the plant cell cycle and numerous developmental processes. Lately, a growing body of evidence suggests that cytokinin has a role in mitigating both abiotic and biotic stress. Cytokinin is essential to defend plants against excessive light exposure and a unique kind of abiotic stress generated by an altered photoperiod. Secondly, cytokinin also exhibits multi-stress resilience under changing environments. Furthermore, cytokinin homeostasis is also affected by several forms of stress. Therefore, the diverse roles of cytokinin in reaction to stress, as well as its interactions with other hormones, are discussed in detail. When it comes to agriculture, understanding the functioning processes of cytokinins under changing environmental conditions can assist in utilizing the phytohormone, to increase productivity. Through this review, we briefly describe the biological role of cytokinin in enhancing the performance of plants growth under abiotic challenges as well as the probable mechanisms underpinning cytokinin-induced stress tolerance. In addition, the article lays forth a strategy for using biotechnological tools to modify genes in the cytokinin pathway to engineer abiotic stress tolerance in plants. The information presented here will assist in better understanding the function of cytokinin in plants and their effective investigation in the cropping system

    The impact of surgical closure of atrial septal defect on the pulmonary hypertension: a prospective observational study

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    Introduction: The most prevalent congenital disease is atrial septal defect. Atrial septal defects that have a left to right shunt result in persistent volume overload in the pulmonary vasculature. So histological changes occur in pulmonary vasculature leads to pulmonary hypertension. Without surgery, both life expectancy and functional ability are reduced. The aim of this study was to observe the impact of surgical closure of atrial septal defect on pulmonary hypertension. Methods: This observational study was done in the department of cardiac surgery, Bangabandhu Sheikh Mujib Medical University from June 2020 to June 2022. Sample size was 24 Patients were evaluated preoperatively, postoperative day of operation through a clinically, ECG, color doppler echocardiography. The statistical analysis was performed by using SPSS version 26.0 for windows software. Results: In my study, the mean age of the patients was 33.33±11.3 years, male female ratio was 1:2. The mean pulmonary artery systolic pressure got decreased from 57.54±7.9 mmHg to 53.29±8.30 mmHg on postoperative day. 75% patients improved into New York heart association class 2 on post operative day. Significant improvement was seen in functional capacity of the patients. 29.2% patients had atrial fibrilation preoperatively, after surgery on post-operative day it became 25%. Conclusions: This study concludes that surgical closure of atrial septal defect leads to a significant reduction in pulmonary hypertension
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