1,720,954 research outputs found
Quantifying differences between ecosystems with particular reference to selection forests in Durango/Mexico
No full textContinuous cover forestry (CCF), which is characterized by selective tree removals in uneven-aged forests, is often believed to be superior to single-species planted forests in addressing a wide range of requirements. Sustainability, which is an important component of CCF, implies limiting the harvested timber volume and often also the structural disturbance by harvest events. Structure is central to CCF silviculture because it determines the current output of products and services as well as the resilience and future dynamics of the managed ecosystem. Therefore, measuring deviations from a desired target structure is a fundamental requirement of CCF. Quantitative description of the differences between ecosystems is necessary for classification of forest types and silvicultural targets, as well as for harvest event analysis and nature conservation. The objective of this study is to present such an approach in the context of exploring new methods of measuring structural differences between forest communities. We investigate the dependence of such differences on the scale of resolution. The general approach is based on measuring discrepancies between relative frequencies involving tree species, tree sizes and spatial patterns. Data from selectively managed mixed and uneven-aged pine-oak forests in Mexico provide the empirical basis for the study. The approaches presented in this study can be used to quantify structural differences between forests and between a given structure and some theoretical target structure. A quantitative measure of the difference between two ecosystems can provide foresters with information about the consequences of particular silvicultural activities. The approach presented in this study therefore offers great potential for analysing the impact of human disturbance on forest ecosystems. (c) 2013 Elsevier B.V. All rights reserved
Estimating balanced structure areas in multi-species forests on the Sierra Madre Occidental, Mexico
No full textThis study presents a method for estimating the minimum area which exhibits a balanced diameter distribution, and the corresponding number of trees, for different tree species and forest types in the Santiago Papasquiaro region in the State of Durango, Mexico. The balanced structure area is defined as the minimum contiguous area that is required for sustainable management of a multi-sized selection forest. A multi-sized forest represents a balanced structure unit if the relationship between harvest and growth can be maintained, using a defined target diameter distribution and disregarding major natural disturbances. The study is based on 17,577 sample plots in uneven-aged forests, which are selectively harvested by local communities. The minimum structure areas that provide a balanced diameter distribution in the diameter at breast height (DBH) interval of 12 to 57 cm vary from 0.4 to 122 ha, depending on the particular tree species. This study has shown that it is possible to identify silvicultural treatments that are conducive to sustainable use. Future management monitoring in the unique forests of Durango will reveal unsustainable harvesting practices more effectively and in a more comprehensive way than before, using the methods presented in this study
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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