1,720,971 research outputs found
Large-Scale Mechanized Agricultural Crop Types across Mato Grosso, Goias, and Matopiba, Brazil
No full textModerate Resolution Imaging Spectroradiometer (MODIS) was used to map annual large-scale mechanized agriculture across Mato Grosso, Tocantins, Goiás, Maranhão, western Bahia, and southern Piauí. All MODIS (MOD13Q1) Enhanced Vegetation Index (EVI), day of year (DOY), and VI Quality 16‐day, 250 m resolution data composited between August 2002 and July 2017 were used.
A growing season is defined as beginning in August and ending in July: the data used to analyze the 2003 growing season span August 1, 2002–July 31, 2003. A published decision‐tree algorithm (Spera et al., 2014, Environmental Research Letters) was modified to incorporate crop cycles and calendars for the states of Tocantins, Goiás, Maranhão, western Bahia, and southern Piauí. The modified Spera et al. algorithm adds single‐cropped corn as a crop class, as it is common in Matopiba.
Crop rotations identified include: (i) single cropping (a single rotation of soy, corn, or cotton within one growing season); (ii) double cropping (a soy‐corn or soy‐cotton rotation within one growing season); and (iii) irrigated agriculture. This algorithm uses metrics that include growing season EVI standard deviation, minima and maxima; it derives green‐up and harvest dates to differentiate natural vegetation from croplands. Due to the 250 m spatial resolution of the data, we mapped only agricultural fields greater than 25 ha. Thus, these cropland estimates are likely relatively conservative.
The results of our algorithm were validated using 883 validation points collected across the Cerrado over the study period using the Landsat data repository within Google Earth Engine. Compositing false‐color Landsat 5 and 7 images (NIR Band 4 as red, SWIR1 Band 5 as green, red Band 3 as blue) from the growing season permitted visual identification and separation of corn, soy, cotton, pasture, and natural vegetation land covers. Across the study region, annual agriculture was distinguished from natural vegetation and pasture with 95% accuracy, and crop types were separated with 87% accuracy. Because pasture and sugarcane are difficult to separate using the phenological signal from a single growing season, we integrated previously published (spatially explicit) sugarcane data (Canasat: Rudorff et al., 2010) into our land‐cover maps.
A data key is published with the files
Large-Scale Mechanized Agricultural Crop Types across Mato Grosso, Goias, and Matopiba, Brazil
No full textModerate Resolution Imaging Spectroradiometer (MODIS) was used to map annual large-scale mechanized agriculture across Mato Grosso, Tocantins, Goiás, Maranhão, western Bahia, and southern Piauí. All MODIS (MOD13Q1) Enhanced Vegetation Index (EVI), day of year (DOY), and VI Quality 16‐day, 250 m resolution data composited between August 2002 and July 2017 were used.
A growing season is defined as beginning in August and ending in July: the data used to analyze the 2003 growing season span August 1, 2002–July 31, 2003. A published decision‐tree algorithm (Spera et al., 2014, Environmental Research Letters) was modified to incorporate crop cycles and calendars for the states of Tocantins, Goiás, Maranhão, western Bahia, and southern Piauí. The modified Spera et al. algorithm adds single‐cropped corn as a crop class, as it is common in Matopiba.
Crop rotations identified include: (i) single cropping (a single rotation of soy, corn, or cotton within one growing season); (ii) double cropping (a soy‐corn or soy‐cotton rotation within one growing season); and (iii) irrigated agriculture. This algorithm uses metrics that include growing season EVI standard deviation, minima and maxima; it derives green‐up and harvest dates to differentiate natural vegetation from croplands. Due to the 250 m spatial resolution of the data, we mapped only agricultural fields greater than 25 ha. Thus, these cropland estimates are likely relatively conservative.
The results of our algorithm were validated using 883 validation points collected across the Cerrado over the study period using the Landsat data repository within Google Earth Engine. Compositing false‐color Landsat 5 and 7 images (NIR Band 4 as red, SWIR1 Band 5 as green, red Band 3 as blue) from the growing season permitted visual identification and separation of corn, soy, cotton, pasture, and natural vegetation land covers. Across the study region, annual agriculture was distinguished from natural vegetation and pasture with 95% accuracy, and crop types were separated with 87% accuracy. Because pasture and sugarcane are difficult to separate using the phenological signal from a single growing season, we integrated previously published (spatially explicit) sugarcane data (Canasat: Rudorff et al., 2010) into our land‐cover maps.
A data key is published with the files
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
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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