1,720,971 research outputs found
Experiment-based prototyping to design and assess cotton management systems in West Africa
No full textDesigning innovative combinations of techniques to improve the sustainability of cropping systems in poor countries is a major
challenge. Here, we developed a prototyping methodology to design, assess and adapt a crop management system for a specific set of constraints. It was applied in Mali with the aim of designing innovative prototypes of cotton management systems to be further tested and adapted by farmers. The prototype aimed at shortening the cotton cycle to overlap the rainy season. The prototype is particularly suited for late sowing and for regions where rainfall is often insufficient. We propose a conceptual model that organizes technical interventions to shorten the cotton cycle. We developed a set of indicators to evaluate the relevance of each modified technical intervention, by comparison with current farmer practices. We evaluated the overall performances of the prototype by taking into account economic, environmental and social factors. The prototype was tested and adjusted in six trials between 2002 and 2004. Our results show that the cotton growth cycle was reduced by 15 days on average, mainly through the shortening of the flowering period. The combination of much higher stand density than currently applied in the region and
application of the growth regulator mepiquat chloride produced a much higher number of bolls per hectare of +69%. The prototype produced higher seed-cotton yields, of +44% on average, and much higher gross margin than the standard cotton management system. The method was therefore successful in designing a new cotton management system that helps farmers to adapt to diverse cropping conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Climate change, climate variability and adaptation options in smallholder cropping systems of the Sudano - Sahel region in West Africa
Get PDF Key words: crop production, maize, millet, sorghum, cotton, fertilizer, rainfall, temperature, APSIM, Mali, In the Sudano-Sahelian zone of West Africa (SSWA) agricultural production remains the main source of livelihood for rural communities, providing employment to more than 60 percent of the population and contributing to about 30% of gross domestic product. Smallholder agricultural production is dominated by rain-fed production of millet, sorghum and maize for food consumption and of cotton for the market. Farmers experience low and variable yields resulting in increasing uncertainty about the ability to produce the food needed for their families. Major factors contributing to such uncertainty and low productivity are climate variability, climate change and poor agricultural management. The objective of this thesis was to evaluate through experimentation, modelling and participatory approaches the real and perceived characteristics of climate variability and change and their effects on crop production in order to identify opportunities for enhancing the adaptive capacity of farmers in the Sudano - Sahelian zone. The general approach was based on, first, understanding the past trend of climate and its effect on the yield of main crops cultivated in southern Mali; second, evaluating together with farmers different adaptation options in the field; third, evaluating climate adaptation options through experimentation on station; and fourth, evaluating the consequences of different adaptation options under different long term scenarios of climate change. Minimum daily air temperature increased on average by 0.05oC per year during the period from 1965 to 2005 while maximum daily air temperature remained constant. Seasonal rainfall showed large inter-annual variability with no significant change over the 1965 – 2005 period. However, the total number of dry days within the growing season increased significantly indicating a change in rainfall distribution. There was a negative effect of maximum temperature, number of dry days and total seasonal rainfall on cotton yield. Farmers perceived an increase in annual rainfall variability, an increase in the occurrence of dry spells during the rainy season, and an increase in temperature. Drought tolerant, short maturing crop varieties and appropriate planting dates were the commonly preferred adaptation strategies to deal with climate variability. Use of chemical fertilizer enhances the yield and profitability of maize while the cost of fertilizer prohibits making profit with fertilizer use on millet. Training of farmers on important aspects of weather and its variability, and especially on the onset of the rains, is critical to enhancing adaptive capacity to climate change. A field experiment (from 2009 to 2011) indicated that for fertilized cereal crops, maize out yielded millet and sorghum by respectively 57% and 45% across the three seasons. Analysis of 40 years of weather data indicated that this finding holds for longer time periods than the length of this trial. Late planting resulted in significant yield decreases for maize, sorghum and cotton, but not for millet. However, a short duration variety of millet was better adapted for late planting. When the rainy season starts late, sorghum planting can be delayed from the beginning of June to early July without substantial reductions in grain yield. Cotton yield at early planting was 28% larger than yield at medium planting and late planting gave the lowest yield with all three varieties. For all four crops the largest stover yields were obtained with early planting and the longer planting was delayed, the less stover was produced. Analysis of predicted future climate change on cereal production indicated that the temperature will increase over time. Generally stronger increases occur in the rcp8.5 scenario compared to the rcp4.5 scenario. The total annual rainfall is unlikely to change. By mid-century predicted maize grain yield losses were 45% and 47% with farmer’s practice in the rcp4.5 and rcp8.5 scenarios respectively. The recommended fertilizer application did not offset the climate change impact but reduced the yield losses to 38% of the baseline yield with farmer’s practice. For millet median yield loss was 16% and 14% with farmer’s practice in the rcp4.5 and rcp8.5 scenario. If the recommended fertilizer rates are applied to millet, the predicted yield losses with farmer’s practice due to climate change are reversed in both climate scenarios. Under future climate change, food availability will be reduced for the all farm types, but that large farm will still achieve food self – sufficiency in terms of energy requirement. The medium and small farm types see a further decrease in food self-sufficiency. Addressing smallholder food self-sufficiency depends upon the capacity of each farm type to appropriately choose the planting date while taking into account the acceptable planting date window for each individual crop.</p
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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