1,720,953 research outputs found
Soybean under high soil temperature and water deficit: soil-plant-microorganism interactions
No full textO crescimento populacional e as mudanças climáticas colocam em risco a segurança alimentar, exigindo aumento da produtividade agrícola em meio a eventos extremos como calor e seca. Esses estresses abióticos afetam diretamente a soja, cultura de grande relevância econômica mundial, comprometendo o crescimento, trocas gasosas, metabolismo, fixação biológica de nitrogênio (FBN) e a dinâmica microbiana do solo. Embora estudos tenham demonstrado que o calor e seca podem atuar de forma combinada, intensificando efeitos deletérios, ou isolada sobre a cultura, ainda há lacunas quanto à resposta específica quando aplicados ao nível do sistema radicular, órgão chave na percepção e sinalização do estresse. Nesse contexto, este trabalho avaliou os efeitos do estresse térmico por altas temperaturas do solo e estresse hídrico, seguido de déficit hídrico, aplicados isoladamente e combinados, sobre o desenvolvimento da soja, FBN e microrganismos do solo. O experimento foi conduzido em casa de vegetação, em esquema fatorial 2 x 2, utilizando duas temperaturas do solo (24°C e 36°C) e dois regimes hídricos (com e sem restrição), totalizando quatro tratamentos com doze repetições. Para a indução do calor e da restrição hídrica na cultura, foi desenvolvido um protocolo experimental que integrou o aquecimento do solo e monitoramento contínuo da umidade, através da utilização de caixas térmicas de polietileno, banhos ultratermostáticos com circulação de água e sensores multiparâmetros de reflectometria no domínio do tempo (TDR). A suspensão da irrigação foi realizada no estádio vegetativo, com posterior reidratação. Foram mensurados parâmetros biométricos e nutricionais da parte aérea, raiz e nódulos. Além disso, foram realizadas análises de conteúdo hídrico foliar, trocas gasosas, quantificação de ureídeos, malondialdeídeo e atividade enzimática do solo. Os resultados indicaram que a disponibilidade hídrica foi determinante para o crescimento foliar, acúmulo de biomassa e ureídeos, além da maior nodulação. O déficit hídrico levou a um aumento da taxa fotossintética líquida, sugerindo mecanismo de osmorregulação como forma de adaptação. A temperatura de 36°C favoreceu o desenvolvimento aéreo e radicular, estimulando a expansão celular e termotolerância. Na condição controle, de 24°C, destacou-se a manutenção da turgescência foliar, a preservação dos nutrientes nas raízes e maior atividade da β-glicosidase no solo. A combinação dos fatores promoveu incrementos na altura e massa seca das plantas, aumento da peroxidação lipídica e da massa seca de nódulos, além de alterações nutricionais específicas, de Mg e Cu na parte aérea e Zn e Mo nos nódulos, e influência sobre a atividade da arilsulfatase. De maneira geral, o calor e a disponibilidade hídrica atuaram como principais indutores das respostas, promovendo tanto sinergismos positivos quanto negativos nas variáveis analisadas. No entanto, os efeitos mais marcantes foram observados sob estresses isolados, evidenciando que o calor e a seca aplicados isoladamente exerceram maior impacto nas variáveis analisadas, enquanto a combinação modulou respostas específicas no sistema solo-planta-microrganismos. Esses resultados reforçam que a resposta da soja frente aos estresses abióticos depende não apenas da intensidade dos fatores combinados, mas também da sua atuação isolada no nível radicular, modulando processos fisiológicos, bioquímicos e microbiológicos essenciais para a adaptação da cultura.The growing global population and climate change pose significant risks to food security, demanding increased agricultural productivity amid extreme events such as heat and drought. These abiotic stresses directly affect soybean, a crop of major global economic importance, compromising growth, gas exchange, metabolism, biological nitrogen fixation (BNF), and soil microbial dynamics. Although previous studies have shown that heat and drought may act synergistically, intensifying detrimental effects, or individually on the crop, gaps remain regarding the specific plant responses when these stresses are applied at the root system level, a key organ for stress perception and signaling. In this context, the present study evaluated the effects of soil heat stress and water stress, followed by water deficit, applied individually and in combination, on soybean development, BNF, and soil microorganisms. The experiment was conducted in a greenhouse using a 2 × 2 factorial design with two soil temperatures (24°C and 36°C) and two water regimes (with and without restriction), totaling four treatments with twelve replicates. To induce heat and water restriction, an experimental protocol was developed integrating soil heating and continuous moisture monitoring through polyethylene thermal boxes, ultrathermostatic water baths with circulation, and multiparameter time-domain reflectometry (TDR) sensors. Irrigation was suspended during the vegetative stage, followed by rehydration, and biometric and nutritional parameters of the shoot, roots, and nodules were measured. Leaf water content, gas exchange, ureide content, malondialdehyde, and soil enzymatic activity were also analyzed. Results showed that water availability was a key determinant of leaf growth, biomass accumulation, ureide concentration, and greater nodulation. Water deficit increased net photosynthetic rate, suggesting activation of osmoregulatory mechanisms as an adaptive response. The 36°C soil temperature favored shoot and root development, stimulating cell expansion and thermotolerance. Under the control condition of 24°C, plants exhibited better maintenance of leaf turgor, preservation of root nutrient status, and higher β-glucosidase activity in the soil. The combination of both stresses promoted increases in plant height and shoot dry mass, enhanced lipid peroxidation, increased nodule dry mass, and induced specific nutritional changes, particularly in Mg and Cu in the shoot and Zn and Mo in nodules, as well as influencing arylsulfatase activity. Overall, heat and water availability acted as major drivers of plant responses, generating both positive and negative synergisms depending on the variable analyzed. However, the most pronounced effects were observed under isolated stresses, demonstrating that heat and drought applied individually exerted stronger impacts, whereas their combination modulated specific responses within the soilplantmicroorganism system. These findings reinforce that soybean responses to abiotic stresses depend not only on the combined intensity of stress factors but also on their isolated effects at the root level, which modulate essential physiological, biochemical, and microbiological processes underpinning crop adaptation
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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