1,720,956 research outputs found
Predicción de la distribución geográfica potencial de las especies arbóreas de las selvas tropicales de México, bajo escenarios de cambio climático global: Estudio en áreas naturales protegidas
Full text linkLas selvas tropicales son los ecosistemas más dinámicos y complejos de la naturaleza, su importancia radica en contener la mayor diversidad genética y biológica de todas las comunidades terrestres y en proporcionar una gran variedad de servicios ambientales. Entre las formas de vida vegetales que alberga, se reconoce a los componentes arbóreos como los más destacables dada su amplia utilidad y cuyo valor es incalculable para el mundo viviente. Sin embargo la permanencia de éstos es incierta, a causa de las modificaciones en los patrones de temperatura y precipitación que se están presentand o debido al cambio climático ( CC ) , lo que representaría cambios futuros en: a) la distribución geográfica de las especies, b) composición en las comunidades vegetales y c) permanencia en las áreas nacionales dedicadas para su protección y/o conservación. El presente estudio analizó los po sibles cambios en la distribución geográfica potencial (permanencia, colonización y extinción) de 92 especies arbóreas tropicales, utilizando Desktop GARP y proyectando bajo escenarios (A2 y B1) de cambio climático para el futuro (2060 y 2090). Se obtuvo e l perfil climático de las áreas potenciales y el perfil bioclimático de las especies. Se identificaron y analizaron los cambios en la composición de las comunidades vegetales por afinidad ambiental a través de un Análisis Multivariante de Varianza (MANOVA) y se realizaron Análisis de Correspondencia y Dendogramas para visualizar grupos con similitudes ambientales. Se identificó la permanencia de las especies y se analizó su composición dentro de cinco Áreas Naturales Protegidas (ANP) en categoría de Reserva de la Biosfera: Calakmul (Campeche), Montes Azules (Chiapas), Sian Ka ́an (Quintana Roo), Sierra Gorda (Querétaro), y Tehuacán – Cuicatlán (Puebla y Oaxaca). Los resultados obtenidos muestran que el 20% (A2) y 37% (B1) de las especies analizadas se verían rel ativamente favorecidas por el CC , al lograr permanecer o incrementar sus áreas de distribución, siendo identificados como elementos característicos de selvas medianas subperennifolias, medianas subcaducifolias y bajas caducifolias; mientras que el 80% ( A2) y 63% (B1) de los árboles podrían disminuir su distribución, siendo m ás afectados o vulnerables al CC aquellos pertenecientes a selvas altas perennifolias, medianas subperennifolias y medianas subcaducifolias. Se identificaron a Chiapas, Guerrero, Hida lgo, Oaxaca, Puebla y Veracruz como los estados con mayor cambio vegetal. Se identificaron posibles cambios en la composición y/o dominancia vegetal dentro de las ANP seleccionadas, siendo Calakmul y Sian Ka ́an las que presentarían considerables disminucio nes principalmente en el escenario A2, Montes Azules mostraría un ligero incremento en el número de especies en ambos escenarios, mientras que Sierra Gorda y Tehuacán – Cuicatlán mantendría sus valores semejantes a los establecidos actualmente. Finalmente se identificaron variaciones en el acomodo espacial de las especies dentro de las ANP, así como cambios significativos en la permanencia de éstas, correspondiendo a algunas de las zonificaciones establecidas de acuerdo al Programa de Manejo.Tropical rainforest are the most dynamic and complex ecosystems in nature. They are of critical importance because they contain the greatest genetic and biological diversity in all terrestrial communities and because they provide a vast variety of env ironmental services. Among the plant life that they are comprised by, the arboreal components are well known because of their great usefulness and, therefore, they are invaluable for life in our world. However, the permanence of these ecosystems is uncerta in because of the several alterations on temperature and precipitation patterns due to climate change (CC). These disturbances potentially mean a) change of the geographical distribution of the species, b) change on the composition of the communities and c ) also a change on the national areas dedicated to their protection and preservation. In this paper have been analyzed the possible changes on the potential geographical distribution (permanency, colonization and extinction) of 92 tropical arboreal species using Desktop GARP and projecting over scenarios A2 and B1 of climate change for 2060 and 2090. Climate profile as well as bioclimatic profile of the species were obtained. The changes on the composition of the communities were identified and analyzed thr ough Multivariate analysis of variance (MANOVA). Also, correspondence analysis and dendrograms were used to recognize the groups with environmental similarities. The permanence of the species was identified and analyzed within five Natural Protected Areas under the category of Biosphere Reserve: Calakmul (Campeche), Montes Azules (Chiapas), Sian Ka ́an (Quintana Roo), Sierra Gorda (Querétaro), y Tehuacán – Cuicatlán (Puebla y Oaxaca). The Results of the investigation show that 20% (scenario A2) and 37% (sce nario B1) of the species will be relatively favored by the CC, as they can maintain or expand their distribution areas. Most of them were identified from medium sub - evergreen forest, medium sub - deciduous and low deciduous. Also, this means that 80% (A2) an d 63% (B1) of the species could reduce their distribution due CC . The most vulnerable could be those from high evergreen forest, medium sub - evergreen, and medium sub - deciduous. The States with major changes were Chiapas, Guerrero, Hidalgo, Oaxaca, Puebla a nd Veracruz. Other changes were found on the vegetal composition and dominance within the PNAs chosen for the study. Calakmul and Sian Ka’an are the ones with considerable reductions on A2. In the other hand, Montes Azules is the only one which could show a slight increase in the number of species on both scenarios, while Sierra Gorda and Tehuacán – Cuicatlán could maintain the same composition and dominance they have at the present. Finally, small changes on the arrangement of the species within the PNAs w as noticed as well as important changes on their permanence, which concurs with the Mana gement Program stablished for those Areas
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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