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Assessment of sediment inflow to a reservoir using the SWAT model under undammed conditions: A case study for the Somerville reservoir, texas, USA

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International Soil and Water Conservation Research 2018年第3期6卷 222-229页

作者： Dagbegnon Clement Sohoulande Djebou Department of Biological and Agricultural Engineering Texas A&M UniversityScoates HallCE-TTI Bldg 303H3135 TAMUSpence StreetCollege StationTX 77843USA texas A&M Transportation Institute-texas A&M University CE-TTI Bldg 303H3135 TAMUSpence StreetCollege StationTX 77843USA

Worldwide, sedimentation represents a major problem for reservoir and dam management due to the related environmental and economic consequences. However, reservoir sedimentation can be significantly mitigated by controlling the rates of sediment loss across a watershed. This article uses a case study to highlight an assessment technique for sustaining effective soil conservation strategies by providing an insight into the spatial variability of sediment loss rates at the watershed scale. The assessment method employs the Soil and Water Assessment Tool (SWAT) and the Modified Universal Sediment Loss Equation (MUSLE) to quantify sediment losses in a case study for the Somerville reservoir, located in texas. The SWAT model was employed to simulate upstream inflows in the studied reservoir watershed. The goodness-of-fit analyses suggested a realistic representation of the watershed behavior and satisfactory values of Nash-Sutcliffe Efficiency were obtained during the calibration and validation stages (0.76 ≤ NSE ≤ 0.69). Then the calibrated SWAT was used to generate MUSLE estimates of soil losses under undammed conditions. A weight-average formulation was developed to evaluate the rates of sediment loss at the sub-basin level. Meaningful contrasts were outlined between the sub-basins located at the downstream, the midstream, and the upstream. The study was able to pinpoint sub-basins with critical needs of soil conservation (sediment loss > 4 t/ha/year). Overall, the outcomes of the case study demonstrated the value of the methodology and that the outcomes may be used to address the complex problem of sedimentation in watersheds with reservoirs.

关键词： Reservoir watershed Sedimentation Runoff SWAT Soil conservation

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CPA Pass Rates in texas： A 12-Year Analysis

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Journal of Modern Accounting and Auditing 2016年第9期12卷 447-452页

作者： Narita Holmes Carol Sullivan University of texas of the Permian Basin Texas USA

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Social distancing and testing as optimal strategies against the spread of COVID-19 in the Rio Grande Valley of texas

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Infectious Disease Modelling 2021年第1期6卷 729-742页

作者： Kristina P.Vatcheva Josef Sifuentes Tamer Oraby Jose Campo Maldonado Timothy Huber María Cristina Villalobos School of Mathematical&Statistical Sciences University of Texas Rio Grande ValleyBrownsvilleTX78520USA School of Mathematical&Statistical Sciences University of Texas Rio Grande ValleyEdinburgTX78539USA School of Medicine The University of Texas Rio Grande ValleyEdinburgTX78539USA

At the beginning of August 2020,the Rio Grande Valley(RGV)of texas experienced a rapid increase of coronavirus disease 2019(abbreviated as COVID-19)cases and *** study aims to determine the optimal levels of effective social distancing and testing to slow the virus spread at the outset of the *** use an age-stratified eight compartment epidemiological model to depict COVID-19 transmission in the community and within *** a simulated 120-day outbreak period data we obtain a post 180-days period optimal control strategy *** results show that easing social distancing between adults by the end of the 180-day period requires very strict testing a month later and then daily testing rates of 5%followed by isolation of positive *** social distancing rates in adults from 50%to 25%requires both children and seniors to maintain social distancing rates of 50%for nearly the entire period while maintaining maximum testing rates of children and seniors for 150 of the 180 days considered in this *** have higher contact rates which leads to transmission based on our model,emphasizing the need for caution when considering school reopenings.

关键词： COVID-19 Mathematical modeling Optimal control Rio Grande Valley(RGV) Testing and social distancing School reopening

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Isolation, Partial Purification and Characterization of texas Live Oak (<i>Quercus fusiformis</i>) Lectin

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Advances in Bioscience and Biotechnology 2015年第7期6卷 470-484页

作者： Ruby A. Ynalvez Carmen G. Cruz Marcus A. Ynalvez Department of Biology and Chemistry Texas A & M International University Laredo Texas USA Department of Social Sciences Texas A & M International University Laredo Texas USA

Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The objective of this study was to isolate and characterize lectin activity in texas Live Oak (Quercus fusiformis). More specifically, the study aimed to determine the lectin’s blood group specificity and pH stability, determine effects of seasonal variation, soil moisture and soil pH on lectin activity. The study also aimed to determine the presence of antifungal activity in Q. fusiformis extracts. Lectin activity was detected and compared via agglutination and protein assays. Protein partial purification was accomplished using diethylaminoethyl ion-exchange chromatography matrix. High Performance Liquid Chromatography (HPLC) was used to assess purity of the lectin. Results showed that Q. fusiformis extracts’ lectin activities are stable at a pH range of 5.2 - 9.2 but with a significant decrease in activity above pH 9.2. The lectin activity was significantly higher when assayed against sheep red blood cells as compared to other blood groups tested. Quercus fusiformis extract is devoid of antifungal activity against Aspergillus niger and Rhizopus stolonifer. The effects of seasonal variation, soil moisture and soil pH do not significantly correlate with lectin activity. Results from HPLC showed presence of three peaks indicating a partial purification of the Q. fusiformis lectin.

关键词： Lectin Quercus fusiformis Protein Purification HPLC Blood Group Specificity pH Stability

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Age, Race and Gender Spatiotemporal Disparities of COPD Emergency Room Visits in Houston, texas

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Occupational Diseases and Environmental Medicine 2015年第1期3卷 1-9页

作者： Faye Anderson Arch Carson Lawrence Whitehead Keith Burau texas A & M AgriLIFE Research Center Beaumont Texas USA

Chronic obstructive pulmonary disease (COPD) is one of the major causes of morbidity and mortality in the United State. The investigation of the continuing increase in its prevalence and mortality has increased attempts to further understand its causes and how to manage it. Understanding the spatial and temporal distribution of COPD emergency room (ER) visits in Harris County (Houston) can guide these efforts in a uniform yet diverse setting like this one. The objectives of this study were to identify the temporal and spatial variations of COPD emergency room visits adjusted by age, gender, ethnicity, day of the week, month, and year, and to estimate the odds ratio of COPD emergency room visits adjusted by the six risk factors. The dataset used were extracted from two resources: ER Utilization Study and Harris County centroid coordinates. Exploratory statistical analyses were conducted to study the spatiotemporal disparities and investigate associations. Logistic regression was performed to estimate the odds ratio of COPD primary diagnosis adjusted for age, race, gender, day of the week, month, and year. The number of COPD ER visits kept increasing from 2004 throughout 2009 but there was a significant increase after the year 2005. Spring and summer had lower visits compared to winter and autumn. Lowest visits were during June and July and higher during December and January. Tuesdays had the highest number of visits compared to the remaining days of the week with Saturdays having had the lowest number of visits. Temporal analyses show the continuous increase in COPD ER visits in Houston as well as the consistent spatial disparities between zip regions. After adjustment for age, race, gender, day of the week, month, and year, there were statistically significant associations between emergency room chronic obstructive pulmonary disease diagnoses in Houston, texas, with these six predictors.

关键词： COPD Houston texas Ozone Particulate Matter Logistic Regression

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Spatiotemporal Analysis of the Effect of Ozone and Fine Particulate on CVD Emergency Room Visits in Harris County, texas

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Open Journal of Air Pollution 2014年第4期3卷 87-99页

作者： Faye Anderson Arch Carson Lawrence Whitehead Keith Burau texas A & M AgriLIFE Research Center at Beaumont Texas USA

Researchers have reported statistically significant associations between air pollutants and cardiovascular disease (CVD). However, few studies have investigated the acute cardiovascular effects of joint exposure to Ozone (O3) and fine particulate matter (PM2.5) in a location so distinctive like Harris County. The objective of this study was to investigate the association between the joint exposure to O3 and PM2.5, and emergency room diagnosis of CVD, in Harris County, texas. Data used include all emergency room (ER) visits, and O3 and PM2.5 levels in the same years. Logistic regression modeled the effect of temperature, relative humidity, wind speed, wind, ozone, and fine particulate matter, averaged by day. Three models were estimated for all visits, visits during the months of April and September of 2005 and 2009, and for visits for patients from zip codes that are close to monitoring stations. A 1 μg/m3 increase in PM2.5 was associated with a 0.4% increase in the odds of cardiovascular disease emergency room diagnoses on the same day

关键词： Cardiovascular Disease Air Pollution Emergency Harris County Ozone Particulate Pollution

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Quantifying the spatial and temporal distribution of tanglehead (Heteropogon contortus) on South texas rangelands

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Ecological Processes 2018年第1期7卷 14-22页

作者： Jose M.Mata Humberto L.Perotto-Baldivieso Fidel Hernández Eric D.Grahmann Sandra Rideout-Hanzak John T.Edwards Michael T.Page Taylor M.Shedd Caesar Kleberg Wildlife Research Institute Texas A&M University-Kingsville700 University Blvd.MSC 218KingsvilleTX 78363USA

Introduction:Tanglehead is a grass native to southwestern US rangelands;however,its prevalence as a native invasive on South texas rangelands has increased rapidly during the last *** areas of monotypic stands have emerged in Jim Hogg,Duval,Brooks,and Kleberg *** aim of this research is to understand the spatial and temporal dynamics of these invasions as a model for the assessment of native invasive *** specific objectives were to(1)evaluate the feasibility of classifying tanglehead using 1-m resolution imagery data,(2)assess the spatial and temporal distribution of tanglehead in relation to soil type and distance from roads,and(3)quantify the temporal and spatial distribution of tanglehead on our study *** combined remote sensing approaches with landscape metrics to quantify the spatial and temporal distribution of tanglehead in five locations across our study *** calculated the normalized difference vegetation index and combined it with the original aerial imagery to conduct an unsupervised classification with the following land cover classes:woody vegetation,tanglehead,non-tanglehead herbaceous,and bare *** type and the distance from roads were assessed to determine the relationship between these factors and tanglehead spatial ***:We were able to successfully map tanglehead using the 1-m *** image classification approach resulted in accuracies greater than 85%for all *** occurred in sandy,loamy sand,and sandy loam *** 70% of tanglehead cover occurred within the first 150 m from the edge of *** cover increased from 7.1%(SE=1.1%)in 2008 to 17.8%(SE=5.4%)in *** established,small patches of tanglehead began aggregating or coalescing with existing stands,thereby creating larger patches over larger ***:Our study has shown the value of analyzing spatiotemporal dynamics of tanglehead with remote sensing techniques and landscape metrics to improve our unders

关键词： distribution landscape sandy

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Multivariate Geostatistical Model for Groundwater Constituents in texas

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International Journal of Geosciences 2014年第13期5卷 1609-1617页

作者： Faye Anderson texas A & M AgriLife Research Center at Beaumont College Station Texas USA

Although many studies have explored the quality of texas groundwater, very few have investigated the concurrent distributions of more than one pollutant, which provides insight on the temporal and spatial behavior of constituents within and between aquifers. The purpose of this research is to study the multivariate spatial patterns of seven health-related texas groundwater constituents, which are calcium (Ca), chloride (Cl), nitrate (NO3), sodium (Na), magnesium (Mg), sulfate (SO4), and potassium (K). Data is extracted from texas Water Development Board’s database including nine years: 2000 through 2008. A multivariate geostatistical model was developed to examine the interactions between the constituents. The model had seven dependent variables—one for each of the constituents, and five independent variables: altitude, latitude, longitude, major aquifer and water level. Exploratory analyses show that the data has no temporal patterns, but hold spatial patterns as well as intrinsic correlation. The intrinsic correlation allowed for the use of a Kronecker form for the covariance matrix. The model was validated with a split-sample. Estimates of iteratively re-weighted generalized least squares converged after four iterations. Matern covariance function estimates are zero nugget, practical range is 44 miles, 0.8340 variance and kappa was fixed at 2. To show that our assumptions are reasonable and the choice of the model is appropriate, we perform residual validation and universal kriging. Moreover, prediction maps for the seven constituents are estimated from new locations data. The results point to an alarmingly increasing levels of these constituents’ concentrations, which calls for more intensive monitoring and groundwater management.

关键词： Multivariate Geostatistical Groundwater Constituents texas

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texas的14．5GHz ECR离子源(英文)

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Chinese Physics C 2007年第S1期31卷 105-107页

作者： D.P.May F.P.Abegglen G.J.Derrig R.S.Olsen Cyclotron Institute Texas A&M UniversityCollege StationTexas77843-3366USA

A new plasma chamber for the texas A&M 14.5GHz ECR ion source ECR2 has been recently installed and the beam analysis line has been recently upgraded with the replacement of the solenoid with a shorter Glaser *** source is now used along with the 6.4GHz ECR1 for injection of beams into the K500 *** new plasma chamber incorporates water-carrying copper tubes,each with an inner diameter of 0.7mm and an outer diameter of 1.8mm,interposed between the NbFeB permanent magnets and the aluminum plasma-chamber *** design allows for a much higher water flow and thus better cooling than the previous design,which used a thin,water-cooled *** source commissioning and operation is described.

关键词： electron-cyclotron-resonance ion source

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The Impact of Climate Change on Hydrology with Geomorphology in Northeast texas

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Journal of Earth Science and Engineering 2018年第1期8卷 1-7页

作者： Joonghyeok Heo Physical Sciences Department University of Texas Permian Basin Odessa Texas 79762 USA

This research evaluates the responses of hydrology and geomorphology regarding climate change and illustrates the change in regional streamflow during the period 1955-2001. The Neches River Basin, texas, is an important source of water for farming, cities, and electrical power production. A 15.9% increase in precipitation and a 20.4% increase in streamflow discharge were observed. The areas of river-flow boundaries also increased. The hydrologic changes appear to be associated with the geomorphic adjustments. To accomplish this research, the Neches River Basin is evaluated using hydro-climate data, historical aerial photography, and GIS in a multiscale approach by using linked geomorphic systems. Changes in the streamflow discharge are main factors that must be considered in undertaking a hydrological impact assessment of climate change.

关键词： Hydrology texas water resources Neches River Basin climate change

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