Modelling the soil water balance and applications using a decision support system (DSSAT v3.5).

Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.Water is a scarce resource used by various stakeholders. Agriculture is one of the users of this resource especially for growing plants. Plants need to take up carbon dioxide to prepare their own food. For this purpose plants have stomatal openings. These same openings are used for transpiration. Quantifying transpiration is important for efficient water resource management and crop production because it is closely related to dry matter production. Transpiration could be measured using a number of methods or calculated indirectly through quantification of the soil water balance components using environmental instruments. The use of models such as the Decision Support System for Agrotechnology Transfer (DSSAT v3.5) is, however, much easier than environmental instruments. Nowadays, with increased capabilities of computers, the use of crop simulation modelling has become a common practice for various applications. But it is important that models, such as DSSAT v3.5, be calibrated and verified before being used for various applications such as long-term risk assessment, evaluation of cultural practices and other applications. In this study the model inputs have been collected first Then the model was calibrated and verified. Next sensitivitY analysis was carried to observe the model behavior to changes in inputs. Finally the model has been applied for long-term risk assessment and evaluation of cultural practices. In this study, the data collected formed the basis forthe minimum dataset needed for running the DSSAT v3.5 model. In addition, the factory given transmission of shading material over a tomato crop was compared to actual measurements. Missing weather data (solar irradiance, minimum and maximum air temperature and rainfall) were completed after checking that it was homogeneous to measurements from nearby automatic weather station. It was found that factory-given transmission value of 0.7 of the shade cloth was different from the actual one of 0.765. So this value was used for conversion of solar irradiance measured outside the shade cloth to solar irradiance inside the shade cloth. Conventional laboratory procedures were used for the analysis of soil physical and chemical properties. Soil water content limits were determined using texture and bulk density regression based equations. Other model inputs were calculated using the DSSAT model. Crop management inputs were also documented for creation of the experimental details file. The DSSATv3.5 soil water balance model was calibrated for soil, plant and weather conditions at Ukulinga by modifying some of its inputs and then simulations of the soil water balance components were evaluated against actual measurements. For this purpose half of the data available was used for calibration and the other half for verification. Model simulations of soil water content (150 to 300 mm and 450 to 600 mm) improved significantly after calibration. In addition, simulations of leaf area index (LA!) were satisfactory. Simulated evapotranspiration (E1) had certain deviations from the measured ET because the latter calculated ET by multiplying the potential ET with constant crop multiplier so-called the crop coefficient. Sensitivity analysis and long-term risk assessments for yield, runoff and drainage and other model outputs were carried out for soil, plant and weather conditions at Ukulinga. For this purpose, some of the input parameters were varied individually to determine the effect on seven model output parameters. In addition, long-term weather data was used to simulate yield, biomass at harvest, runoff and drainage for various initial soil water content values. The sensitivity analysis gave results that conform to the current understanding of the soil-plant atmosphere system. The long-term assessment showed that it is risky to grow tomatoes during the winter season at Ukulinga irrespective of the initial soil water content unless certain measures are taken such as the use of mulching to protect the plants from frost. The CROPGRO-Soya bean model was used to evaluate the soil water balance and gro'W1:h routines for soil, plant and weather conditions at Cedara. In addition, cultural practices such as row spacing, seeding rate and cultivars were also evaluated using longterm weather data. Simulations of soil water content were unsatisfactory even after calibration of some of the model parameters. Other model parameters such as LAI, yield and flowering date had satisfactory agreement with observed values. Results from this study suggest that the model is sensitive to weather and cultural practices such as seeding rates, row spacing and cultivar maturity groups. The general use of decision support systems is limited by various factors. Some of the factors are: unclear definition of clients/end users; no end user input prior to or during the development of the DSS; DSS does not solve the problems that the client is experiencing; DSS do not match their decision-making style; producers see no reason to change the current management practices; DSS does not provide benefit over current decision-making system; limited computer ownership amongst producers; lack of field testing; producers do not trust the output due to the lack of understanding of the underlying theories of the models utilized; cannot access the necessary data inputs; lack of technical support; lack of training in the development ofDSS software; marketing and support constraints; institutional resistances; short shelf-life of DSS software; technical constraints, user constraints and other constraints. For successful use of DSS, the abovementioned constraints have to be solved before their useful impacts on farming systems could be realized. This study has shown that the DSSAT v3.5 model simulations of the soil water balance components such as evapotranspiration and soil water content were unsatisfactory while simulations of plant parameters such as leaf area index, yield and phonological stages were simulate to a satisfactory standard. Sensitivity analysis gave results that conform to the current understanding of the soil-plant -atmosphere system. Model outputs such as yield and phonological stages were found to sensitive to weather and cultural practices such as seeding rates, row spacing and cultivar maturity groups. It ha been further investigated that the model could be used for risk assessment in various crop management practices and evaluation of cultural practices. However, before farmers can use DSSAT v3.5, several constraints have to be solved

Determinants of long acting and permanent contraceptive methods utilization among married women of reproductive age groups in western Ethiopia: a cross-sectional study

Introduction: in Ethiopia information on the level of utilization of the long-term and permanent contraceptive methods and associated factors is lacking. The aim of this study was to understand the determinant factors of long-acting and permanent contraceptive methods use among married women of reproductive age in Western Ethiopia. Methods: a community-based cross- sectional study design was employed. Multi-stage sampling was used to select 1003 study participants. Data was collected from April 10 to April 25,2014 using a pre- tested structured questionnaire. The data were entered using Epi-info version 3.5.1 and exported to SPSS version 20 for analysis. Multivariate logistic regression analysis was done to identify predictors of long-acting and permanent contraceptive methods at 95% CL. Results: use of long acting and permanent contraceptive methods in this study was found to be 20%. Survey results showed a significant positive association between utilization of long acting and permanent contraceptive methods andwomen's education (AOR=1.72, 95%CI = 1.02 - 3.05), women's occupation (AOR = 2.01, 95% CI = 1.11 -3.58), number of live children (AOR = 2.42, 95% CI: 1.46- 4.02), joint fertility related decision (AOR = 6.11, 95% CI: 2.29- 16.30) ,having radio/TV (AOR = 2.31, 95% CI: 1.40 - 3.80), and discussion with health care provider about long acting and permanent contraceptive methods (AOR = 13.72, 95% CI: 8.37 - 22.47). Conclusion: efforts need to be aimed at women empowerment, health education, and encouraging open discussion of family planning by couples

Electrografting of isophthalic acid monolayer and covalent attachment of antibody onto carbon surfaces

In this study, a 5-diazonium isophthalic acid was synthesized and electrografted onto glassy carbon (GCE) and screen-printed carbon (SPCE) electrodes. SPCE was used to demonstrate fabrication of a miniature device and to compare with conventional glassy carbon electrodes. The isophthalic acid (IPA) electrografted thin film was used for the immobilization of anti-methotrexate antibody (Ab) using carbodiimide activation chemistry to form antibody modified surfaces, GCE-IPA-Ab and SPCE-IPA-Ab. The GCE -IPA-Ab and SPCE-IPA-Ab surfaces were used as capacitive biosensors for the detection of methotrexate (MTX) in phosphate buffer (pH 7.4) using capacitive electrochemical impedance spectroscopy (EIS). The EIS data was analyzed using singular value decomposition (SVD). Principal component regression analysis gave R2 values of 0.99 for both the GCE-IPA-Ab and SPCE-IPA-Ab surfaces. The detection limit from the calibration curve of the GCE-IPA-Ab and SPCE-IPA-Ab was calculated to be 7.0 pmol.L−1 and 5.5 pmol.L−1, respectively

Adherence to prenatal iron-folic acid supplementation in low- and middle-income countries (LMIC):A protocol for systematic review and meta-analysis

BACKGROUND: Daily iron-folic acid supplementation reduces anemia and various adverse obstetric outcomes such as preterm delivery, low birthweight, hemorrhage, and perinatal and maternal morbidity and mortality. However, its supplementation has not been successful that attributed to several determinants including poor adherence. Therefore, we aimed to conduct a systematic review and meta-analysis on the prevalence and determinants of adherence to prenatal iron-folic acid supplementation in low- and middle-income countries. In addition, we will develop a conceptual framework in the context of low- and middle-income countries (LMIC). METHODS/DESIGN: We will search PubMed, MEDLINE, EMBASE, EBSCO, Web of Science, SCOPUS, WHO Global Index Medicus, and African Journals Online (AJOL) databases to retrieve relevant literatures. Observational (i.e., case-control, cohort, cross-sectional, survey, and surveillance reports) and quasi-randomized and randomized controlled trial studies conducted in LMIC will be included. The Newcastle-Ottawa Scale (NOS) and Joanna Briggs Institute (JBI) critical appraisal checklist will be used to assess the quality of observational and randomized controlled trial studies respectively. The pooled prevalence and odds ratio of determinants of adherence will be generated using a weighted inverse-variance meta-analysis model. Statistical heterogeneity among studies will be assessed by Cochran's Q χ2 statistics and Higgins (I2 statistics) method. The result will be presented using forest plots and Harvest plots when necessary. Furthermore, we will perform Jackknife sensitivity and subgroup analysis. Data will be analyzed using comprehensive meta-analysis software (version 2). DISCUSSION: Contemporary evidence about the prevalence and determinants of adherence in LMIC will be synthesized to generate up-to-date knowledge. To our knowledge, this is the first systematic review. It would have substantial implications for researchers, clinicians, and policymakers for optimizing maternal and child health outcomes in LMIC. SYSTEMATIC REVIEW REGISTRATION: The protocol has been registered on International Prospective Register of Systematic Review (PROSPERO), University of York Center for Reviews and Dissemination ( https://www.crd.york.ac.uk/ ), registration number CRD42017080245

Core–Shell Carbon Nanofibers-NiFe Structure on 3D Porous Carbon Foam: Facilitating a Promising Trajectory toward Decarbonizing Energy Production

In this work, a low-cost, light-weight, highly efficient, and durable electrode in which NiFe-layered double hydroxide is electrodeposited on a carbon nanofiber (CNF) core supported on a carbon foam (CF) is introduced. The resulting 3D NiFe-CNFs-CF electrode shows excellent oxygen evolution reaction and hydrogen evolution reaction performance in alkaline media. When used as an anode and a cathode in the same cell, a current density of 10 mA cm−2 is achieved, at a cell voltage of 1.65 V. Moreover, good stability over a long testing time (50 h) is demonstrated. The ternary hybrid electrode gives rise to an excellent performance-to-weight ratio owing to its very low bulk density (≈34 mg cm−3) inherited from super lightweight components composed of CF and CNFs. The developed electrode can potentially be used in large-scale alkaline water electrolysis, in facilities such as offshore hydrogen production platforms, which can complement the variable renewable energy production of wind farms through hydrogen storage and fuel cells.</p

Seroprevalence of Strongyloides stercoralis infection in a South Indian adult population

BACKGROUND: The prevalence of Strongyloides stercoralis infection is estimated to be 30–100 million worldwide, although this an underestimate. Most cases remain undiagnosed due to the asymptomatic nature of the infection. We wanted to estimate the seroprevalence of S. stercoralis infection in a South Indian adult population. METHODS: To this end, we performed community-based screening of 2351 individuals (aged 18–65) in Kanchipuram District of Tamil Nadu between 2013 and 2020. Serological testing for S. stercoralis was performed using the NIE ELISA. RESULTS: Our data shows a seroprevalence of 33% (768/2351) for S. stercoralis infection which had a higher prevalence among males 36% (386/1069) than among females 29.8% (382/1282). Adults aged ≥55 (aOR = 1.65, 95% CI: 1.25–2.18) showed higher adjusted odds of association compared with other age groups. Eosinophil levels (39%) (aOR = 1.43, 95% CI: 1.19–1.74) and hemoglobin levels (24%) (aOR = 1.25, 95% CI: 1.11–1.53) were significantly associated with S. stercoralis infection. In contrast, low BMI (aOR = 1.15, 95% CI: 0.82–1.61) or the presence of diabetes mellitus (OR = 1.18, 95% CI: 0.83–1.69) was not associated with S. stercoralis seropositivity. CONCLUSIONS: Our study provides evidence for a very high baseline prevalence of S. stercoralis infection in South Indian communities and this information could provide realistic and concrete planning of control measures