1,720,964 research outputs found
Adubação nitrogenada como atenuador dos efeitos da salinidade da água de irrigação utilizada para produção de forragem no semiárido
Get PDFA qualidade e a quantidade das culturas agrícolas estão sob contínua e grave ameaça de vários estresses abióticos, sendo a salinidade um dos mais importantes. A salinidade afeta o metabolismo das plantas por efeitos primários por meio do déficit hídrico, toxicidade iônica e desbalanço nutricional, além dos efeitos secundários que são os danos oxidativos. Estudos realizado em campo demostram efeito positivo da adubação nitrogenada sobre a salinidade do solo e da água utilizada para irrigação. Nesse sentido, objetivou-se avaliar efeito da adubação nitrogenada e da irrigação com água salina durante a produção do sorgo e do milheto no semiárido brasileiro. A pesquisa foi conduzida, em condições de campo, na UAST, Serra Talhada–PE. Utilizou-se o delineamento experimental em blocos casualizados, disposto em parcelas subdivididas, com quatro repetições, arranjados no esquema fatorial 4 x 4, referentes à 4 lâminas (28, 36, 44, 52% ETc) de irrigação e 4 doses (0, 100, 200, 300 kg ha-1) de nitrogênio, adotando o sistema Sorgo + Milheto, sendo o sorgo a cultura principal. O semeio foi realizado no dia 7 de abril de 2017, colocando na média 30 sementes por metro linear, com espaçamento de 25 cm entre o sorgo e milheto. As lâminas de irrigação foram baseadas na ETc, sendo obtida pela equação ETc = ETo x Kc (do sorgo). A adubação nitrogenada consistiu no parcelamento de 1/3 na semeadura e 2/3 na cobertura. Ao final do ciclo de cada cultura, altura de plantas (AP), diâmetro do caule (DC), o número de folhas vivas e mortas foi contado, produtividade de massa verde e seca foi estimada, teores de N-total, Na+, K+ e Cl- foram determinados. Os dados foram submetidos à análise de variância e as variáveis ajustadas ao modelo de regressão, utilizando o Software SAS. De acordo com os resultados obtidos nesse experimento, pode-se concluir que adubação nitrogenada e a irrigação com água salina beneficiaram o crescimento da cultura do sorgo e do milheto, expresso em altura, diâmetro caulinar, número de folhas vivas e mortas, biomassa verde e seca. A adubação nitrogenada favorece a absorção do N-total e potássio pelas plantas, no entanto, inibiu a absorção dos íons cloreto e sódio na mesma condição, isto é, o nitrogênio atenuou os efeitos da salinidade da água de irrigação. O consórcio favorece incremento na produção de biomassa. Houve maior acúmulo de N-total e cloreto na parte aérea do milheto quando comparado ao sorgo.The quality and quantity of agricultural crops are under continuous and serious threat of several abiotic stresses, with salinity being one of the most important. Salinity affects the metabolism of plants by primary effects through water deficit, ionic toxicity and nutritional imbalance, in addition to the side effects that are oxidative damages. Studies carried out in the field demonstrate a positive effect of nitrogen fertilization on soil salinity and water used for irrigation. In this sense, the objective was to evaluate the effect of nitrogen fertilization and irrigation with saline water during the production of sorghum and millet in the Brazilian semi-arid region. The research was conducted, under field conditions, at UAST, Serra Talhada-PE. The experiment was carried out in a randomized complete block design, arranged in subdivided plots, with four replications, arranged in the 4 x 4 factorial scheme, referring for 4 irrigation blades (28, 36, 44, 52% ETc) and 4 doses (0, 100 , 200, 300 kg ha-1) of nitrogen, adopting the Sorghum + Milheto system, being sorghum the main crop. Seeding was carried out on April 7, 2017, placing 30 seeds per linear meter on the average, spacing 25 cm between sorghum and millet. The irrigation blades were based on the ETc, being obtained by the equation ETc = ETo x Kc (of the sorghum). Nitrogen fertilization consisted of 1/3 in sowing and 2/3 in coverage. At the end of the crop cycle, plant height, stem diameter, number of live and dead leaves counted, yield Green and dry mass was estimated, N-total, Na+, K+ and Cl- contents were determined. The data were submitted to analysis of variance and the variables adjusted to the regression model, using SAS Software. According to the results obtained in this experiment, it can be concluded that nitrogen fertilization and irrigation with saline water benefited the growth of the sorghum and millet crop expressed in height, stem diameter, number of lives and dead leaves, green and dry biomass. Nitrogen fertilization favors the absorption of N-total and potassium by plants, however, it inhibited the absorption of chloride and sodium ions in the same condition, that is, nitrogen attenuated the salinity effects of irrigation water. The consortium favors an increase in biomass production. There was greater accumulation of N-total and chloride in the shoot of millet when compared to sorghum crop
INTERAÇÃO SALINIDADE, BIOFERTILIZANTE E ADUBAÇÃO POTÁSSICA NA FORMAÇÃO DE MUDAS DE MARACUJAZEIRO AMARELO
Get PDFThe yellow passion fruit (Passiflora edulis f. Flavicarpa Deg) is the most important species of
the genus Passiflora, known from north to south of Brazil due to its nutritional and medicinal
properties. Based on scientific information, the yellow passion fruit is seen as a very sensitive
culture to the effects of salinity. In this context, it was aimed to evaluate the effect of bovine
biofertilizer in mitigating the effects of salinity of irrigation water and to evaluate the potassium
fertilization during the emergence and the formation of yellow passion fruit seedlings. The
study was conducted under greenhouse environment of the Soils Department and Rural
Engineering, belonging to the Agrarian Sciences Center of the Federal University of Paraiba,
located in Areia-PB. The treatments were distributed in randomized block design with four
replications, arranged in a factorial 5 x 3 x 2, corresponding five levels of electrical conductivity
of irrigation water (0,3; 1,0; 2,0; 3,0 and 4.0 dS m-1), three types of K fertilization (without
potassium, potassium chloride and potassium sulfate) in soil with and without bovine
biofertilizer applied in liquid form at 1:1 ratio (bio: water) and 10 % of the substrate volume,
24 hours before seeding. The variables analyzed were: electrical conductivity of the soil
saturation extract, emergency speed index, plant height, stem diameter, number of leaves, leaf
area, dry matter of shoot and root, leaf contents of chlorophyll a, b and total. The increase of
the water salinity and bovine biofertlizer inhibited the biometric growth, biomass production
and the leaf chlorophyll contents of yellow passion fruit.O maracujazeiro amarelo (Passiflora edulis f. flavicarpa Deg) é a espécie mais importante do
gênero passiflora, conhecido do norte ao sul do Brasil devido às suas características alimentícias
e medicinais. Baseado em informações científicas, o maracujazeiro amarelo é visto como uma
cultura muito sensível aos efeitos da salinidade. Nesse contexto, objetivou-se avaliar o efeito
do biofertilizante bovino em atenuar os efeitos da salinidade da água de irrigação e avaliar a
fonte de potássio durante a emergência das plântulas e a formação de mudas de maracujazeiro
amarelo. O trabalho foi desenvolvido em ambiente telado do Departamento de Solos e
Engenharia Rural, pertencente ao Centro Ciências Agrárias da Universidade Federal da Paraíba,
localizado no município de Areia-PB. Os tratamentos foram distribuídos em blocos
casualizados, com quatro repetições, arranjados no esquema fatorial 5 x 3 x 2, correspondente
cinco níveis de condutividade elétrica da água de irrigação (0,3; 1,0; 2,0; 3,0 e 4,0 dS m-1), três
níveis de adubação potássica (sem potássio, cloreto de potássio e sulfato de potássio) no solo
sem e com biofertilizante bovino, aplicado na forma líquida na proporção 1:1 (Bio: Água) e 10
% do volume do substrato, 24 horas antes da semeadura. As variáveis analisadas foram:
condutividade elétrica do extrato de saturação do solo, índice de velocidade de emergência,
altura de plantas, diâmetro caulinar, número de folhas, área foliar, matéria seca da parte aérea
e da raiz, índices foliares de clorofila a, b e total. O aumento da salinidade da água de irrigação
e o biofertlizante inibiram o crescimento, a produção de biomassa e os índices foliares de
clorofila do maracujazeiro amarelo
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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