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Effect of inorganic arsenic in paddy soil on the migration and transformation of selenium species in rice plants

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Journal of Environmental Sciences 2024年第9期143卷 35-46页

作者： Ganga raj.pokhrel Kaiteng Wang Kaiyang Ying Yongchen Wu Ze Wang Xi Zhu Can Qu Hong Li Fengfu Fu Guidi Yang Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring Key Laboratory for Medicinal Plant Chemistry and Chemical BiologyCollege of JunCao Science and EcologyFujian Agriculture and Forestry UniversityFuzhou 350002China Department of Chemistry Birendra Multiple CampusTribhuvan UniversityChitwan 00977-44200BharatpurNepal Key Laboratory for Analytical Science of Food Safety and Biology of Ministry of Education Fujian Provincial Key Lab of Analysis and Detection for Food SafetyCollege of ChemistryFuzhou UniversityFuzhou 350116China

Selenium(Se)in paddy rice is one of the significant sources of human Se ***,the effect of arsenic(As)pollution in soil on the translocation of Se species in rice plants is *** this research,a pot experiment was designed to examine the effect of the addition of 50 mg As/kg soil as arsenite or arsenate on the migration of Se species from soil to indica Minghui 63 and *** results showed that the antagonism between inorganic As and Se was closely related to the rice cultivar and Se oxidation state in *** to the standalone selenate treatment,arsenite significantly(p<0.05)decreased the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,sheaths,leaves,brans and kernels of both cultivars by 21.4%-100.0%,40.0%-100.0%,41.0%-100%,5.4%-96.3%,11.3%-100.0% and 26.2%-39.7% respectively,except for selenocystine in the kernels of indica Minghui 63 and selenomethionine in the leaves of indica Minghui 63 and the stems of indica *** also decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,brans and kernels of both cultivars by 34.9%-100.0%,30.2%-100.0%,11.3%-100.0% and 5.6%-39.6%respectively,except for selenate in the stems of indica Minghui ***,relative to the standalone selenite treatment,arsenite and arsenate decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenite only in the roots of indica Minghui 63 by 45.5%-100.0%.Our results suggested that arsenite and arsenate had better antagonism toward Se species in selenate-added soil than that in selenite-added soil;moreover,arsenite had a higher inhibiting effect on the accumulation of Se species than arsenate.

关键词： Rice(Oryza sativa L.) Inorganic arsenic Selenium species Translocation Antagonistic effect

Choice of providers for treating a neglected tropical disease:an empirical analysis of kala azar in Nepal

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Asian Pacific Journal of Tropical Medicine 2011年第3期4卷 234-240页

作者： shiva raj Adhikari Siripen Supakankunti M Mahmud Khan Patan Multiple Campus Tribhuvan UniversityNepal Faculty of Economics Chulalongkorn UniversityThailand Tulane University New OrleansUSA

Objective:To examine the choice of healthcare providers for treating kala azar(KA) in Nepal. Methods:Information was collected from clinically diagnosed KA patients seeking care from public hospitals located in KA endemic *** survey collected information from more than 25 percent of total KA cases in the *** empirical estimation of probability of choosing a provider-type as a first contact healthcare provider,a multinomial logit model was defined with five alternative options with self care as the reference ***:The empirical model found that price of medical care services,income of households,knowledge of patients on KA and KA treatment,borrowing money,age of patient,perceived quality of provider types,*** the likelihood of seeking care from the alternative options considered in the *** variables have expected signs and are *** with earlier *** price and income elasticity were found to be very high indicating that poorer households are very sensitive to price and income changes,even for a severe disease like *** the empirical models, we have analyzed two policy instruments:demand side financing and interventions to improve the knowledge index about ***:Due to high price elasticity of KA care and high spillover effects of KA on the society,policy makers may consider demand side financing as an instrument to encourage utilization of public hospitals.

关键词： Neglected tropical disease Kala azar Nepal

Decision-making process of Kala Azar care: results from a qualitative study carried out in disease endemic areas of Nepal

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Infectious Diseases of Poverty 2013年第1期2卷 105-111页

作者： shiva raj Adhikari Siripen Supakankunti M Mahmud Khan Department of Economics Patan Multiple CampusTribhuvan UniversityKathmanduNepal Faculty of Economics Chulalongkorn UniversityBangkokThailand Department of Health Services Policy and Management University of South CarolinaCarolinaUSA

Background:Analysis of consumer decision making in the health sector is a complex process of comparing feasible alternatives and evaluating the levels of satisfaction associated with the relevant *** paper makes an attempt to understand how and why consumers make specific decisions,what motivates them to adopt a specific health intervention,and what features they find attractive in each of the ***:The study used a descriptive-explanatory design to analyze the factors determining the choices of healthcare *** was collected through focus group discussions and in-depth ***:The results suggest that the decision making related to seeking healthcare for Kala Azar(KA)treatment is a complex,interactive *** and family members follow a well-defined road map for decision *** process of decision making starts from the recognition of healthcare needs and is then modified by a number of other factors,such as indigenous knowledge,healthcare alternatives,and available *** and individual characteristics also play important roles in facilitating the process of decision *** results from the group discussions and in-depth interviews are consistent with the idea that KA patients and family members follow the rational approach of weighing the costs against the benefits of using specific types of medical ***:The process of decision making related to seeking healthcare follows a complex set of steps and many of the potential factors affect the decision making in a non-linear *** analysis suggests that it is possible to derive a generalized road map of the decision-making process starting from the recognition of healthcare needs,and then modifying it to show the influences of indigenous knowledge,healthcare alternatives,and available resources.

关键词： Kala Azar Decision-making process Utilization Nepal

Choices of health care financing schemes for resource poor country: An analysis of Nepal’s experiences

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Health 2013年第8期5卷 1295-1302页

作者： shiva raj Adhikari Department of Economics Patan Multiple Campus Tribhuvan University Lalitpur Nepal

An appropriate health care financing scheme can improve the efficient, equitable, and effective use of health care resources;however, each popular health care financing scheme has some advantages and disadvantages. The designing of health care financing strategy to fit with the country specific features is not straightforward. In resource poor country, allocation of resources for health care services are always critical and frequently unstable due to nuances annual budget process, small fiscal space, uncertainties in contributions of external development partners. Considerable quantities of country specific researches require for the choice of an appropriate health care financing scheme. The paper illustrates possible better options for the government to pursue the goal of ensuring that the poor receive more benefits. The paper compares the benefit incidences and cost of services with different options purposed for primary health care services by utilizing recently collected data from different hospitals in Nepal. The paper offers an alternative policy such as a universal free care below the district level services;but in the district level which is top level of primary care, “extended targeted free health care” may be an efficient, fair, and relatively simple approach.

关键词： Health Care Financing Benefit Incidence Cost Poor Nepal

Assessment of Heavy Metals in Deep Groundwater Resources of the Kathmandu Valley, Nepal

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Journal of Environmental Protection 2016年第4期7卷 516-531页

作者： Suman Man Shrestha Kedar Rijal Megh raj.pokhrel Central Department of Environmental Science Tribhuvan University Kirtipur Nepal Central Department of Chemistry Tribhuvan University Kirtipur Nepal

A study was carried out to address distribution of some heavy metals in deep groundwater resources of the Kathmandu Valley. Groundwater samples were analyzed for pH, ORP, EC, iron, manganese, zinc, and arsenic in 41 deep groundwater wells during pre monsoon and post monsoon seasons for two consecutive years. The study showed elevated concentrations of iron and manganese in the groundwater of the valley. The occurrence of elevated concentrations of arsenic was also exhibited and observed up to 0.160 mg/L. The spatial distribution patterns demonstrated elevated levels of EC, iron, manganese, zinc, and arsenic in central groundwater district (CGWD) of the valley. The monitored parameters except ORP are not significantly correlated with studied time series, inferring similar distribution of the metals. Correlation analysis and principal component analysis (PCA) were performed to find out relationships among examined parameters and metals. The ORP has strong negative correlations with iron, manganese, and arsenic, suggesting reductive mobilization mechanism of the metals in the groundwater. PCA results showed that iron and manganese with high positive loading factors were due to common natural source of origin of these metals in the groundwater, while negative loading factors of pH and ORP indicated that iron and manganese mobilization was favorable in low pH and reducing environment. Cluster analysis (CA) evidenced high mineralization in most of the wells in the CGWD.

关键词： Heavy Metals Deep Groundwater Principal Component Analysis Cluster Analysis Mineralization

Cybersecurity: A Stochastic Predictive Model to Determine Overall Network Security Risk Using Markovian Process

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Journal of Information Security 2017年第2期8卷 91-105页

作者： Nawa raj.pokhrel Chris P. Tsokos Department of Mathematics and Statistics University of South Florida Tampa USA

There are several security metrics developed to protect the computer networks. In general, common security metrics focus on qualitative and subjective aspects of networks lacking formal statistical models. In the present study, we propose a stochastic model to quantify the risk associated with the overall network using Markovian process in conjunction with Common Vulnerability Scoring System (CVSS) framework. The model we developed uses host access graph to represent the network environment. Utilizing the developed model, one can filter the large amount of information available by making a priority list of vulnerable nodes existing in the network. Once a priority list is prepared, network administrators can make software patch decisions. Gaining in depth understanding of the risk and priority level of each host helps individuals to implement decisions like deployment of security products and to design network topologies.

关键词： Vulnerability Attack Graph Markov Model Exploitability CVSS FIRST NVD IDS

Assessment of Arsenic Contamination in Deep Groundwater Resources of the Kathmandu Valley, Nepal

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Journal of Geoscience and Environment Protection 2015年第10期3卷 79-89页

作者： Suman Man Shrestha Kedar Rijal Megh raj.pokhrel Central Department of Environmental Science Tribhuvan University Kirtipur Kathmandu Nepal Central Department of Chemistry Tribhuvan University Kirtipur Kathmandu Nepal

This study was carried out to assess arsenic in deep groundwater resources in the Kathmandu Valley, Nepal and to predict arsenic mobilization process in relation to iron, manganese, pH and ORP. Forty-one deep groundwater samples were collected during pre monsoon and post monsoon in 2013. The depths of the wells were ranged from 84 to 304 m. In pre monsoon and post monsoon, arsenic concentration in 17% and 26% of examined groundwater wells, respectively exceeded permissible World Health Organization (WHO) guideline value of 0.010 mg/L for drinking water. The concentrations of arsenic were in the range between < 0.003 to 0.137 mg/L. The study demonstrated elevated concentrations of iron and manganese in the groundwater. Arsenic is highly correlated with iron and manganese. The strong negative correlation between arsenic and ORP indicates that arsenic mobilization occurs under reducing condition. These distinct relationships indicate that arsenic release is considered to be affected by the reductive dissolution of Fe/Mn oxides in the groundwater. Arsenic has very weak negative correlation with pH suggesting less effect of pH on arsenic mobilization. Arsenic is not significantly correlated with the season which infers similar distribution of arsenic in both seasons. Arsenic varies spatially in groundwater of the valley showing high concentrations in central groundwater district.

关键词： Arsenic Deep Groundwater Reductive Dissolution Kathmandu Valley

Goal Programming for Solving Fractional Programming Problem in Fuzzy Environment

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Applied Mathematics 2015年第14期6卷 2360-2374页

作者： Anil Kumar Nishad shiva raj Singh Department of Mathematics Banaras Hindu University Varanasi India

This paper is comprised of the modeling and optimization of a multi objective linear programming problem in fuzzy environment in which some goals are fractional and some are linear. Here, we present a new approach for its solution by using α-cut of fuzzy numbers. In this proposed method, we first define membership function for goals by introducing non-deviational variables for each of objective functions with effective use of α-cut intervals to deal with uncertain parameters being represented by fuzzy numbers. In the optimization process the under deviational variables are minimized for finding a most satisfactory solution. The developed method has also been implemented on a problem for illustration and comparison.

关键词： Fuzzy Sets Trapezoidal Fuzzy Number (TFN) Multi-Objective Linear Programming Problem (MOLPP) Multi-Objective Linear Fractional Programming Problem (MOLFPP)

Cybersecurity: Time Series Predictive Modeling of Vulnerabilities of Desktop Operating System Using Linear and Non-Linear Approach

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Journal of Information Security 2017年第4期8卷 362-382页

作者： Nawa raj.pokhrel Hansapani Rodrigo Chris P. Tsokos Department of Mathematics and Statistics University of South Florida Tampa FL USA School of Mathematical and Statistical Sciences University of Rio Grande Valley Edinburg TX USA

Vulnerability forecasting models help us to predict the number of vulnerabilities that may occur in the future for a given Operating System (OS). There exist few models that focus on quantifying future vulnerabilities without consideration of trend, level, seasonality and non linear components of vulnerabilities. Unlike traditional ones, we propose a vulnerability analytic prediction model based on linear and non-linear approaches via time series analysis. We have developed the models based on Auto Regressive Moving Average (ARIMA), Artificial Neural Network (ANN), and Support Vector Machine (SVM) settings. The best model which provides the minimum error rate is selected for prediction of future vulnerabilities. Utilizing time series approach, this study has developed a predictive analytic model for three popular Desktop Operating Systems, namely, Windows 7, Mac OS X, and Linux Kernel by using their reported vulnerabilities on the National Vulnerability Database (NVD). Based on these reported vulnerabilities, we predict ahead their behavior so that the OS companies can make strategic and operational decisions like secure deployment of OS, facilitate backup provisioning, disaster recovery, diversity planning, maintenance scheduling, etc. Similarly, it also helps in assessing current security risks along with estimation of resources needed for handling potential security breaches and to foresee the future releases of security patches. The proposed non-linear analytic models produce very good prediction results in comparison to linear time series models.

关键词： ARIMA NVD ANN OS SVM CVE SMAPE