1,720,984 research outputs found
Modelling and predicting durum wheat yield and quality in Mediterranean environments
Full text linkDurum wheat (Triticum turgidum L. var durum) is mainly produced and consumed in the Mediterranean environments, where yield and grain protein content are usually constrained by environmental variables.
A 1.4 million ha of durum wheat are currently grown in Italy with an average production of 4 million tons and an average yield of 3.8 t/ha. 73% of the production, which accounts for 65% of total production, is located in South Italy, while in the Northern regions yield is usually higher due to different pedology and climatic conditions. The cultivation of durum wheat in Italy generates a vast range of allied activities, “upstream” such as seed and technical supplies industries, and “downstream” such as storage centries, primary and secondary transformation industries. Due to the strategic importance of the durum wheat production, a tool able to accurately predict yield and grain protein content before harvesting and an assessment of the agronomic and environmental variables that most influence the quantitative and qualitative parameters in the Mediterranean environments, can be of great value in policy planning. Currently the national and international agricultural statistics services provide regular updates during the growing season of total acreage planted with a specific crop, as well as the expected yield levels. Traditionally, forecasts have been based on a combination of scouting reports as well as statistical techniques based on historical data. Based on the expected yield, the price of grain can vary significantly, with a high impact on both commodity prices and farmers incomes. Growing season forecasts of crop yields are therefore of considerable interest also to commodity market participants and price analysts. Crop simulation models can play a critical role in crop yield and quality forecasting applications: the relatively low cost and speed of assessment makes crop growth simulation models promising for areas where meteorological information is readily available. The overall aim of the present study was to
test the predictive capability of Delphi system, based on the AFRCWHEAT2 model, for yield and quality forecast at local and regional scale in long-term analysis and to determine the general principles underlying how Mediterranean environments affects grain protein content (GPC). General findings allowed us to implement a new simple model with high predictive ability in terms of GPC, only based on gridded climate data, supporting strongly the key role played by weather pattern for a crop such as durum wheat under rainfed conditions
Downscaling landsat land surface temperature over the urban area of Florence
Full text linkA new downscaling algorithm for land surface temperature (LST) images retrieved from Landsat Thematic Mapper (TM) was developed over the city of Florence and the results assessed against a high-resolution aerial image. The Landsat TM thermal band has a spatial resolution of 120 m, resampled at 30 m by the US Geological Survey (USGS) agency, whilst the airborne ground spatial resolution was 1 m. Substantial differences between Landsat USGS and airborne thermal data were observed on a 30 m grid: therefore a new statistical downscaling method at 30 m was developed. The overall root mean square error with respect to aircraft data improved from 3.3 °C (USGS) to 3.0 °C with the new method, that also showed better results with respect to other regressive downscaling techniques frequently used in literature. Such improvements can be ascribed to the selection of independent variables capable of representing the heterogeneous urban landscape
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
A Novel Computational Model of the Wheat Global Market with an Application to the 2010 Russian Federation Case
Full text linkIn this paper, we build a computational model for the analysis of international wheat spot price formation, its dynamics and the dynamics of quantities traded internationally. The model has been calibrated using FAOSTAT data to evaluate its in-sample predictive power. The model is able to generate wheat prices in twelve international markets and traded wheat quantities in twenty-four world regions. The time span considered is from 1992 to 2013. In our study, particular attention was paid to the impact of the Russian Federation's 2010 grain export ban on wheat price and quantities traded internationally. Among other results, we found that the average weighted world wheat price in 2013 would have been 3.55% lower than the observed one if the Russian Federation had not imposed the export ban in 2010
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
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
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