1,720,964 research outputs found
Analysis of passive microwave data for large area environmental monitoring
No full textTraditionally, "large area" monitoring from satellites has been accomplished using the Advanced Very High Resolution Radiometer (AVHRR), however, the use of this dataset can be significantly affected by the presence of cloud cover. The Special Sensor Microwave Imager (SSM/I) records microwave emissions from the Earth surface. Microwave emissions are independent of cloud cover and therefore provide a useful dataset in areas of significant cloud cover. The objectives of this work were to evaluate the synergism between the AVHRR and SSM/I sensors, establish a method of scaling between the two datasets and interpret the microwave emissions for the purpose of soil moisture monitoring. Scaling between the two datasets was accomplished by adding together the locational accuracies and pixel resolution of both datasets. Microwave polarization differences were found to be inversely related with ground temperature. Furthermore, use of polarization differences facilitated observation of the temporal evolution of microwave emissions over three ecoregions. SSM/I data recorded at 19 GHz was shown to be linearly related to surface moisture even in the presence of vegetation
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
Identification and samping of large fields using Landsat imagery within a GIS
No full textProviding accurate information derived from satellite data on agroecosystems requires ground truth cognizant of spatial and temporal variations. To understand the interactions between satellite data and agroecosystems, training sites need to be located. It is in this context that agricultural fields larger than 14.5 hectares were identified in southern Ontario from Landsat TM data using an unsupervised classification procedure. The classification successfully identified large fields. The spatial resolution of Landsat TM data and natural variability in crops were found to be limiting factors in the identification of large fields. A stratified random sampling scheme was employed to select agricultural fields larger than 14.5 hectares to be used for calibration of satellite data. Three to four fields were located in clusters at road intersections to improve ground truthing efficiency. It was found that more training sites were required in areas where the physiographic diversity increased. It was difficult to satisfy the dual objectives of selecting training areas representative of spatial variations in agriculture and creating an efficient sampling design
Changes in soil morphology on a chronosequence of no-till agricultural soils
Get PDFSoil scientists, particularly pedologists, have begun to realize that important information on soil processes lies 'within' genetic soil horizons. Short-term changes in soil morphology are evaluated in this thesis through utilizing relatively new techniques. Sampling bulk soil in fine increments (i.e. 1 cm thick layers) with soil depth, 137Cs as a marker of short-term changes, and the image analysis of the soil micromorphology on thin sections were techniques employed to assess the recent soil genesis along a chronosequence of no-till soils in southern Ontario. It was determined that earthworms, the lack of organic matter incorporation, and physical disruption by annual tillage were important factors influencing the morphology of the soils after 11 years of no-till conservation management. Earthworm populations were much greater in the no-till soils and this had a major influence on aggregation, incorporation of surface-applied organic matter and soil porosity. Soil organic matter increased in the top 5 cm of the soil profile as the number of years in no-till increased. The no-till soils had greater horizontally-oriented elongated macropores in the top 5 to 15 cm of the soil profile relative to soils in conventional tillage due to the lack of tillage and exposure to annual freeze-thaw processes. Rounded macropores increased with the number of years in no-till as these pores are maintained each year due to the lack of tillage and greater faunal activity in the no-till soils. Micromorphological evidence indicated surface crust formation in some of the conventionally-tilled soils. Other micromorphological evidence showed that the top 3 cm of soils in no-till for 11 years were similar to those in a never-cultivated woodlot soil. This research concluded that major morphological changes occur in top 30 cm of soils as they are converted to no-till from conventional tillage practice
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
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