1,720,964 research outputs found
Modeling Ghanaian cocoa farmers' decision to use pesticide and frequency of application: the case of Brong Ahafo Region
Full text linkPesticides are a significant component of the modern agricultural technology that has been widely adopted across the globe to control pests, diseases, weeds and other plant pathogens, in an effort to reduce or eliminate yield losses and maintain high product quality. Although pesticides are said to be toxic and exposes farmers to risk due to the hazardous effects of these chemicals, pesticide use among cocoa farmers in Ghana is still high. Furthermore, cocoa farmers do not apply pesticide on their cocoa farms at the recommended frequency of application. In view of this, the study assessed the factors influencing cocoa farmers' decision to use pesticide and frequency of pesticide application. A total of 240 cocoa farmers from six cocoa growing communities in the Brong Ahafo Region of Ghana were selected for the study using the multi-stage sampling technique. The Probit and Tobit regression models were used to estimate factors influencing farmers' decision to use pesticide and frequency of pesticide application, respectively. Results of the study revealed that the use of pesticide is still high among farmers in the Region and that cocoa farmers do not follow the Ghana Cocoa Board recommended frequency of pesticide application. In addition, cocoa farmers in the study area were found to be using both Ghana Cocoa Board approved/recommended and unapproved pesticides for cocoa production. Gender, age, educational level, years of farming experience, access to extension service, availability of agrochemical shop and access to credit significantly influenced farmers' decision to use pesticides. Also, educational level, years of farming experience, membership of farmer based organisation, access to extension service, access to credit and cocoa income significantly influenced frequency of pesticide application. Since access to extension service is one key factor that reduces pesticide use and frequency of application among cocoa farmers, it is recommended that policies by government and non-governmental organisations should be aimed at mobilizing resources towards the expansion of extension education. In addition, extension service should target younger farmers as well as provide information on alternative pest control methods in order to reduce pesticide use among cocoa farmers. Furthermore, extension service/agents should target cocoa farmers with less years of farming experience and encourage cocoa farmers to join farmer based organisations in order to decrease frequency of pesticide application
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Synthesis of Dimeric Pyridinium Phenolate Dyes and Investigation of their Photophysical Properties
No full textSolvatochromic dyes have advanced the field of organic materials chemistry with their intriguing photophysical properties. They have applications as solvent polarity sensors as well as probes for studying solvent effects in supramolecular chemistry, chemical sensing, and examining biological processes. This study focuses on synthesising a range of bridged pyridinium based chromophores and investigating their photophysical behavior. This work aims to explore how solvatochromism and exciton coupling enhances the optical and electronic properties of these dyes. To do this, dimer 4,4\u27-((1,3-phenylenebis(methylene))bis(pyridine-1-ium-1,4-diyl))diphenolate (19), 4,4\u27-((1,2-phenylenebis(methylene))bis(pyridine-1-ium-1,4-diyl))diphenolate (21) and reference compound, 4-(1-benzylpyridin-1-ium-4-yl)phenolate (23) were synthesised in good yields using simple SN2 reaction. UV-vis spectroscopic analysis of these dyes was performed and compared against each other.
The absorption spectrum profiles revealed that dimer 19 and 21 exhibited an enhanced negative solvatochromism compared to monomer 23. It was also observed that bichromophoric 19 and 21 exhibited intense absorption with two peaks as a result of exciton coupling. The two chromophores interact intramolecularly, resulting in the splitting and an intense absorption band. This new findings will expand the applications of these dimeric phenolate dyes in the field of material organic chemistry
Impact of COVID-19 on Household Food Insecurity in Malawi
Full text linkThe enforcement of policy measures by the government of Malawi as a result of COVID-19 disrupted people’s way of life with significant ramifications on food security and the economy. This study assesses the food security status of 1,127 households in Malawi during COVID-19 and determine the factors that influence the ending food security of households to the shock of COVID-19 using Malawi's Living Standard Measurement Survey (LSMS) data collected by the Malawian Government National Statistical Office in 2020/2021. To assess the food security status of households in Malawi, the surveyed households were categorized based on the eight standard Food Insecurity Experience Scale (FIES) questions generated by the Food and Agricultural Organization. Our results from the FIES categories show that after COVID-19, about 33 percent of the surveyed households were food secure, 11 percent were mildly food insecure, 20 percent were moderately food insecure, and 36 percent were severely food insecure. To determine the factors that influence the ending food security of households to shocks, we employed an ordered probit regression model. Our results show that owning a family business and livestock increases the probability of a higher level of ending food security. Stocking up on food increases the probability of higher levels of ending food security. Also, job loss and a reduction in the number of times to the market increase the probability of lower levels of ending food security. Furthermore, the study revealed that larger household sizes increase the probability of a lower level of ending food security. Finally, household heads with a higher level of education increase the probability of higher levels of ending food security
Four Essays in International Trade and Economic Development
Full text linkThis dissertation comprises four essays investigating the impact of trade agreements on trade outcomes and the relationship between export diversification and economic growth.
Chapter 1 investigates the effect of the U.S. African Growth and Opportunity Act (AGOA) on Sub-Saharan African (SSA) countries’ exports to the U.S. We used synthetic control method and U.S.-AGOA data. The study reveals that AGOA member nations experienced a significant 324.37 million yearly. State-level impacts varied, notably affecting areas with specific demographic characteristics such as higher poverty level, greater Black population, lower percentage of the population with a high school degree, and higher percent female population.
Chapter 4 investigates the relationship between export diversification and economic growth in thirty-nine Sub-Saharan African countries. We used macroeconomic data from United Nations Conference on Trade and Development (UNCTAD) and the Arellano-Bond difference generalized method-of-moment estimator, the study finds positive economic growth effects with better corruption control and governance quality, showcasing export diversification beyond the growth-optimized level. This was confirmed through robustness checks using country-fixed effect regression, ensuring the stability of the findings
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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