Scientific Research and Essays最新文献

{"title":"Bayesian analysis to detect change-point in two-phase Laplace model","authors":"A. Jafari, M. Yarmohammadi, A. Rasekhi","doi":"10.5897/SRE2016.6441","DOIUrl":"https://doi.org/10.5897/SRE2016.6441","url":null,"abstract":"The general form of the change-point problem is to determine the unknown location , based on an ordered sequence of observations such that, the two groups of observation and follow distinct models. In this paper the problem of changepoint detection of two-phase Laplace model is considered. Our object is to find the location of random variables where the parameters of their model are changed. The Bayesian method is used to estimate the parameters. Then by simulation studies, the implementation of proposed method will be discussed. For estimate the parameters of the model, and the procedure of the change-point detection the R2OpenBUGS Package in R is used. Finally, a few empirical applications are presented to illustrate the usefulness of the procedures.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"187-193"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6441","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slow translation of Tropical Africas wealth in medicinal plants into the clinic: Current biomolecular infrastructural capacity and gaps in sub-Saharan universities","authors":"P. F. Kamba, Edson Ireeta Munanura, Bruhan Kaggwa, Stephen Lutoti, H. B. Aguma, R. O. Adome","doi":"10.5897/SRE2016.6435","DOIUrl":"https://doi.org/10.5897/SRE2016.6435","url":null,"abstract":"Tropical Africa has one of the world’s largest endowments in medicinal plant diversity. However, this potential has not been translated into pure drugs of proven efficacy and safety synonymous with modern pharmaceuticals. The basis for the slow translation of Tropical Africa’s medicinal plant wealth into value-added medicines acceptable in the doctor’s clinic is not clear. In this work, we sought to understand the patterns of research on African medicinal plants in general, and the capacity of sub-Saharan universities to conduct value-building research on plant-derived medicines in particular, using an extensive online search.  A near-exponential growth in number of publications over the period 2000 to 2015 was found. However, most of the primary literature is on preliminary pharmacological assays and ethnobotany/ethnopharmacology. Only 6% of the publications are on advanced investigations such as isolation, structure elucidation and semi-synthetic optimization of natural compounds, structural studies of drug targets, ligand binding studies and cell biological assays, yet they are fundamental to progression of lead compounds into useful drugs. Assessment of the current biomolecular infrastructure in 25 sub-Saharan universities found severe shortage of essential equipment in many of them. Only 64, 68, 36 and 68% of the sampled universities have high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR) equipment, respectively. East, Central and West Africa are particularly deficient in most of the key equipment, and some available are non-functional. The purchase cost of most biomolecular research equipment is between USD 30,000 and USD 500,000. Further analysis shows that the cost of establishing comprehensive biomolecular research infrastructure in at least one university per sub-Saharan nation is negligible relative to their gross domestic products (GDPs). Thus, even with the current economic resources, sub-Saharan African countries would upgrade biomolecular research capabilities in their leading universities without disrupting other economic priorities. \u0000 \u0000 Key words: Medicinal plants, biomolecular, Tropical Africa, nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), analog synthesis.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"174-186"},"PeriodicalIF":0.0,"publicationDate":"2016-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6435","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the environmental effects of international outsourcing: Study of the iron casting industry","authors":"M. Bahadir","doi":"10.5897/SRE2016.6421","DOIUrl":"https://doi.org/10.5897/SRE2016.6421","url":null,"abstract":"The international outsourcing of intermediate products is a common practice in manufacturing. Although outsourcing labor- and resource-intensive production to developing countries is based on financial motives, the decision should also be evaluated from an environmental perspective at a global scale. In this study, the environmental effects of four supply chain scenarios are analyzed through a life-cycle assessment (LCA) of a cast iron component. The study reveals that when upstream manufacturing activities are performed in Mexico, the Global Warming Potential (GWP), Ozone Depletion Potential (ODP) and ecotoxicity levels might be comparable with those of manufacturing activities performed in the U.S. However, in China- and India-based outsourcing scenarios, the GWP, ODP and ecotoxicity levels are two to three times higher than those of U.S.-based scenarios. The main causes of the higher levels of GWP, ODP and ecotoxicity in China and India are related to differences in the amount of scrap metal usage, sources of electricity generation, transportation modes, material transport distances, and emissions control practices. \u0000 \u0000 Key words: Life cycle assessment (LCA), global warming, ozone depletion, ecotoxicity, international trade, metal casting.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"160-173"},"PeriodicalIF":0.0,"publicationDate":"2016-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6421","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71216980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the road to improving knowledge and access to female condom in Nigeria: Evidence from Edo, Delta and Lagos states","authors":"Jamilah Mohammed-Jantabo, Richard Olukolade, S. Adebayo","doi":"10.5897/SRE2015.6287","DOIUrl":"https://doi.org/10.5897/SRE2015.6287","url":null,"abstract":"The female condom is a relatively new product that is intended to serve the dual role of protecting against unwanted pregnancy and sexually transmitted infections (STI). Very few studies have been conducted on the use of female condom in Nigeria. Therefore, information is lacking about its continued use, particularly among women at high risk of HIV and other STI. With the above consideration, the Society for Family Health conducted a quantitative and measuring access and performance (MAP) baseline survey to find out the population of women using a female condom to assess product availability and accessibility using pre-defined criteria for coverage, quality of coverage, access and equity of access in Edo, Delta and Lagos states of Nigeria. Data were entered and cleaned using SPSS 13.0. In general, the MAP study found that female condom suffers from lack of public awareness, limited patronage and stock-out; which may be due to absence of promotional efforts.   To enable a successful acceptability of female condom in the Nigerian market, a comprehensive introductory and outreach programme needs to be developed. There is a need to consider the involvement of men, use of peer educators and service providers who might impact on an individual’s motivation to use the female condom. \u0000 \u0000   \u0000 \u0000 Key words: Female condom, Nigeria, knowledge, quantitative method, measuring access and performance (MAP) study, Edo, Delta, Lagos.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"153-159"},"PeriodicalIF":0.0,"publicationDate":"2016-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2015.6287","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the association between diabetes mellitus and hearing loss: Genetic mutation, neuropathy and microangiopathy","authors":"M. Akbar","doi":"10.5897/SRE2016.6423","DOIUrl":"https://doi.org/10.5897/SRE2016.6423","url":null,"abstract":"Diabetes mellitus (DM) has progressively increased in global prevalence. Recent studies have found that patients with DM may suffer from hearing impairment as a chronic complication. The effect of hearing loss may impair the quality of life of patients which affects functional, social, as well as psychological aspects. Both DM and hearing loss are considered to be associated, although this correlation remains elusive. There are three theories proposed to establish the association, which are microangiopathy, neuropathy and genetic mutation in mitochondrial DNA (mtDNA). This essay will initially discuss the importance of mtDNA mutations and neuropathy, as well as microangiopathy, in developing the expression of deafness in diabetes mellitus. It will also consider the limitation of these respective theories to explain the mechanism of hearing loss in diabetes mellitus patients. \u0000 \u0000 Key words: Diabetes mellitus, hearing loss, mtDNA mutation, microangiopathy, neuropathy.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"64 1","pages":"147-152"},"PeriodicalIF":0.0,"publicationDate":"2016-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6423","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of compound layer growth during nitriding of pure iron","authors":"E. M. Hernández, J. Otero, A. Jiménez, R. D. Santiago, R. Martinez, F. Castillo, J. Oseguera","doi":"10.5897/SRE2016.6405","DOIUrl":"https://doi.org/10.5897/SRE2016.6405","url":null,"abstract":"This paper presents a physical model which describes the layer growth kinetics and the nitrogen concentration profiles during gaseous or plasma nitriding of pure iron. The model is related to a one dimensional moving boundary value problem where the initial concentration profiles are assumed to be linear and a new boundary condition at the diffusion zone is proposed. The model is solved by using a classical finite difference scheme (FDM-CS) and the Heat Balance Integral Method (HBIM). Due to the proposed boundary condition at the diffusion zone, the numerical solutions can be validated through a simple physical analysis of mass transport theory in the asymptotic time limit. The results obtained are compared, and observed to be in good agreement with available experimental data and other approximate solutions reported in the literature. \u0000 \u0000 Key words: Advanced characterization, coatings, plasma nitriding, finite difference, heat balance.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"135-146"},"PeriodicalIF":0.0,"publicationDate":"2016-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71216905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New methodology for microarray spot segmentation and gene expression analysis","authors":"A. Hudaib, H. Fakhouri, Rawan Ghnemat","doi":"10.5897/SRE2015.6378","DOIUrl":"https://doi.org/10.5897/SRE2015.6378","url":null,"abstract":"DNA microarray analysis is the main core in genome mapping. Each microarray image contains millions of information about genes. Microarray analysis is considered one of the most recent and important technologies in exploring the genome. One of the key steps in microarray analysis is to extract gene information from the gene spots, these information represent gene expression levels in the microarray. This paper proposes a new methodology to improve microarray spot analysis based on spot extracted segments. It concentrates on each spot segment area independently rather than analyzing all the spots area together of the microarray image. This paper provides a formal model to enhance the intensity values obtained from gene expression levels of the microarray at any intensity expressed level. It also this paper presents the adaptive threshold techniques to be used for microarray segmentation. The experimental results show that the mean of the gene expression intensity value was 87.77. \u0000 \u0000   \u0000 \u0000 Key words: Microarray images, microarray analysis, image segmentation, gridding, microarray addressing, spot localization, spot extraction.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"126-134"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2015.6378","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sentiment analysis as a way of web optimization","authors":"M. Osama, K. Ahmad, A. Dana","doi":"10.5897/SRE2016.6381","DOIUrl":"https://doi.org/10.5897/SRE2016.6381","url":null,"abstract":"Web optimization is the process of optimizing the web to increase visibility or rank of websites in search engines. Furthermore, this process is also viewed from multiple perspectives, from optimizing inter-server communication that offers the best responses to users’ queries and provides targeted advertisements to users of a website. With this regard, the process of automatic classification and information extraction from users’ comments, also known as Sentiment Analysis (SA) or opinion mining, becomes vital to offer users the best online experience, based on their preferences. There are numerous algorithms available for SA. Therefore before applying any algorithm for polarity detection, pre-processing on comments is carried out. This study analyzes how we can write an algorithm for performing SA, and how different types of processing that are applied to initial data such as stemming or eliminating stop words affect the performance of this algorithm. The results show that even when a small sample is used, sentiment analysis can be done with a high accuracy (over 70%) if appropriate natural language processing algorithms are applied. Having a method for guessing sentiments could enable us, to excerpt opinions from the internet and predict online customer’s favorites, which could ascertain valuable for commercial or marketing research.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"90-96"},"PeriodicalIF":0.0,"publicationDate":"2016-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6381","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strain field determination using displacement gradient model and unified least-squares technique","authors":"Lin Yi-chun, Han Jen-Yu","doi":"10.5897/SRE2015.6377","DOIUrl":"https://doi.org/10.5897/SRE2015.6377","url":null,"abstract":"Deformation analysis is crucial to applications in geodesy, structural engineering, and geology, of which the main goal is to detect the behaviors of a deformed body. Traditional deformation analyses rely on a limited number of observations and thus give a relatively poor description of the strain field on the entire object. In this study, a method based on the displacement gradient model and unified least-squares adjustment is proposed to improve classical deformation analysis. Corresponding quality assessment and sensitivity analysis are derived accordingly to better assess significant deformation. Furthermore, by applying nearest neighbor searching and a triangulated irregular network, the efficiency of analyzing a vast number of observations is improved. Numerical experiments based on real data suggested that the proposed approach detected behaviors of a deformed body in an effective and efficient way. Consequently, the strain field on an object can be obtained rapidly and accurately using the proposed method and a large point dataset. \u0000 \u0000 Key words: Deformation analysis, strain field, dispersed point data, structural health monitoring.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"80-89"},"PeriodicalIF":0.0,"publicationDate":"2016-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2015.6377","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of rain-fed maize-based vegetable production systems in Northern Ghana","authors":"Y. Issaka, J. Seidu, A. Tenkouano","doi":"10.5897/SRE2015.6326","DOIUrl":"https://doi.org/10.5897/SRE2015.6326","url":null,"abstract":"The study was conducted in Northern Ghana comprising of the Northern, Upper East and Upper West regions. The objective of the study was to analyse maize-based rain-fed vegetable production systems with a view to explore their potential to contribute to food and income security for rural households. A combination of qualitative and quantitative data collection methods were employed during the study. Questionnaires were employed to collect quantitative data, through semi-structured interviews on socio-cultural and economic dimensions of vegetable production including household characteristics, consumer perspectives and the economics of production and consumption of vegetables. The targeted respondents were households and consumers. Rain-fed cereal-based vegetable production is a key component of the traditional farming system in Northern Ghana and served as the main source of vegetables for rural households. The results showed that all households in the study area integrated vegetables with maize mainly for home consumption. Only a few households cultivated vegetables with the sole purpose of income. \u0000 \u0000   \u0000 \u0000 Key words: Agriculture, rain-fed, household, vegetable, maize-based, Ghana, farming system.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"11 1","pages":"64-75"},"PeriodicalIF":0.0,"publicationDate":"2016-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2015.6326","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71217126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}