734 research outputs found

    Estimativa da produtividade e estado nutricional da cultura do algodão irrigado via técnicas de sensoriamento remoto.

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    Tese (Doutorado em Recursos Naturais) - Universidade Federal de Campina Grande, Centro de Tecnologia e Recursos Naturais, Campina Grande, PB. Orientador: Bernardo Barbosa da Silva; Orientador: Napoleão Esberard de Macêdo Beltrão - Embrapa Algodão

    Bacillus Subtilis SMC Complexes Juxtapose Chromosome Arms as They Travel from Origin to Terminus

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    Structural maintenance of chromosomes (SMC) complexes play critical roles in chromosome dynamics in virtually all organisms, but how they function remains poorly understood. In the bacterium Bacillus subtilis, SMC-condensin complexes are topologically loaded at centromeric sites adjacent to the replication origin. Here we provide evidence that these ring-shaped assemblies tether the left and right chromosome arms together while traveling from the origin to the terminus (>2 megabases) at rates >50 kilobases per minute. Condensin movement scales linearly with time, providing evidence for an active transport mechanism. These data support a model in which SMC complexes function by processively enlarging DNA loops. Loop formation followed by processive enlargement provides a mechanism by which condensin complexes compact and resolve sister chromatids in mitosis and by which cohesin generates topologically associating domains during interphase. Keywords: SMC; ParB; condensin; cohesion; loop extrusion; TADNational Institutes of Health (U.S.) (Grant GM082899

    Estimation of nitrogen and phosphorus content in cotton leaves from medium-resolution satellite images.

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    Satellite images are valuable tools to assess the nutritional status of plants and, thus, understand the variability of cotton yield in farmers' fields. By identifying soil variability and nutritional crop reflectance, Precision Agriculture (PA) techniques enable more precise variable rate application of inputs such as fertilizers and pesticides. One important PA technique is geostatistics, resulting in interpolated maps that assist in evaluation during the crop cycle. These kriged maps provide a unique opportunity to overcome both spatial and temporal scaling challenges and understand the factors leading to crop yield. This study combines conventional statistical analysis, spatial regression modeling of georeferenced data, and vegetation indices assessment from medium-resolution satelitte images to support decisions on improving cotton yield. The experiments were conducted in a 44.8 ha commercial field in Goiás state, Brazil. Multispectral satellite images at 56 m spatial resolution were collected in a rainfed cotton field on 04/01/2011 and 04/10/2012 from the AWiF sensor during the peak flowering cotton stage. Measures of leaf nitrogen (N) and phosphorus (P) contents were determined over previously georeferenced central points of 70 plots of a regular grid, each one measuring 80X80 m. Using descriptive statistics and geostatistical analyses, data were analyzed by building and setting semivariograms and kriging interpolation. The best correlation was found between IVs and nitrogen contents of cotton leaves. Results indicated that NDVI, MSAVI, and SAVI were the best indices for estimating P contents at cotton peak flowering. Identifications of spatial differences were possible using geostatistical methods with remote sensing data obtained from medium-resolution satellite images, allowing the identification of distinct nutritional needs and growth status of canopy to cotton plants

    Avaliação da formação de corpos lúteos acessórios e dosagem de progesterona em cabras da raça Saanen após o uso de hCG.

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    Avalia a formação de CLa e concentração plasmática de progesterona em decorrência da administração de hCG em cabras cinco dias após a última monta natural. Conclui-se que o tratamento com hCG 5 dias após a última MN induziu um efeito luteotrópico, e não a formação de CLa, antecipando o momento da ocorrência da elevação das concentração de progesterona plasmática. [Evaluation of formation of accessories corpora lutea and plasma progesterone concentration in Saanen goats treated with hCG]

    Optical Trapping in a Dark Focus

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    The superposition of a Gaussian mode and a Laguerre-Gauss mode with =0,p0\ell=0,p\neq0 generates the so-called bottle beam: a dark focus surrounded by a bright region. In this paper, we theoretically explore the use of bottle beams as an optical trap for dielectric spheres with a refractive index smaller than that of their surrounding medium. The forces acting on a small particle are derived within the dipole approximation and used to simulate the Brownian motion of the particle in the trap. The intermediate regime of particle size is studied numerically and it is found that stable trapping of larger dielectric particles is also possible. Based on the results of the intermediate regime analysis, an experiment aimed at trapping living organisms in the dark focus of a bottle beam is proposed.Comment: 14 pages, 9 figure

    Avaliação do uso da prostaglandina na sincronização do estro associado ou não ao uso do hCG em cabras.

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    Resumo: O objetivo deste estudo foi avaliar a eficácia da sincronização do estro sobre os parâmetros ovarianos e comportamentais de cabras da raça Toggenburg. A administração da hCG no inicio do estro é capaz de antecipar a ovulação e promover um aumento no numero de ovulações. Estes resultados devem ser observados para estabelecimento momento ideal para a IA. [Evaluation of the use prostaglandin in synchronization the estrus associated or not the hCG in goats]

    Possíveis impactos do projeto: "Uso de sêmen resfriado e inseminação artificial em caprinos leiteiros na República de Cabo Verde".

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    Resumo - Este artigo procura discutir o contexto do projeto ?Uso de sêmen resfriado e inseminação artificial em caprinos leiteiros na República de Cabo Verde?, suas implicações no sistema de criação de caprinos leiteiros, bem como seu impacto nos planos social, ambiental e econômico. Possible impacts of the project: "use of chilled semen and artificial insemination in dairy goats on Cape Verde Republic?. Abstract - This article intent to discuss the aspects involved in the project ?Use of chilled semen and artificial insemination in dairy goats on Cape Verde Republic? their implications on dairy goats rearing and also, the social, the economic, and the environmental impacts.Anais do 15o. Simpósio Paranaense de Ovinocultura, 3o. Simpósio Paranaense de Caprinocultura, 3o. Simpósio Sul Brasileiro de Ovinos e Caprinos, Pato Branco, PR, out., 2011

    Inseminação artificial em caprinos leiteiros com sêmen resfriado por 24 ou 48 horas.

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    Resumo - Objetivou-se, avaliar a viabilidade da utilização do sêmen caprino diluído em meio tris-gema 2,5% resfriado a 5°C e armazenado por diferentes períodos (24 ou 48 horas). Foram inseminadas por via transcervical 133 cabras sem raça definida e nativas da República de Cabo Verde, divididas aleatoriamente em dois tratamentos T24 e T48. O estro foi sincronizado com a utilização de esponjas intra-vaginais contendo 60 mg de acetato de medroxiprogesterona por seis dias; 37,5 ?g de D-cloprostenol e 200 UI de eCG 24 horas antes da retirada da esponja. Foram utilizados três reprodutores da Raça Canárias. Para resfriar e manter o sêmen a 5o C foi utilizado o Botutainer® (Biotech Botucatu, Reprodução Animal, Botucatu - SP) adaptado. Não houve diferença (P > 0,05) entre os padrões seminais para os diferentes períodos de resfriamento (T24 - 58,8% ± 11,1 de motilidade e 2,9 ± 0,5 de vigor; T48 - 51,3% ± 2,5 de motilidade e 2,8 ± 0,3 de vigor), o que permitiu obter taxas de parição similares em ambos os tratamentos (T24 - 26,5% e T48 - 21,5%). A eficiência dos protocolos testados permitiu a disseminação de genética caprina na República de Cabo Verde. Conclui-se que o sêmen caprino, resfriado por 48 horas a 5ºC, tem o mesmo potencial de fertilização do sêmen resfriado por 24 horas a 5ºC. Artificial insemination in dairy goats with cooled semen stored for 24 or 48 hours. Abstract - The fertilizing capacity of goat semen diluted in tris-egg yolk 2.5% chilled at 5oC for 24 or 48 hours was evaluated. Transcervical artificial insemination was performed in 133 goats that were divided, randomly, into two treatments T24 and T48. The estrus was synchronized by the mean of intra-vaginal sponges containing 60 mg of medroxyprogesterone acetate for six days; 37.5 mg of D-cloprostenol and 200 IU of eCG, 24 hours before removing the sponge. Three Canarian?s Buck were used. For cooling and keeping the semen at 5oC a Botutainer® (Biotech Botucatu, Animal Reproduction, Botucatu - SP) was adapted and used. There was no difference (P > 0.05) between the seminal patterns for the different periods of cooling (T24 - 58.8%±11.1 for motility and 2.9±0.5 for strength; T48 - 51.3%±2.5 for motility and 2.8±0.3 for strength), which allowed to obtain similar pregnancy rates in both treatments (T24 ? 26.5% and T48 - 21,5%). The efficiency of the tested protocols allowed the dissemination of goat?s genetic material in the Republic of Cape Verde. It was concluded that goat semen, cooled for 48 hours at 5ºC, has the same fertility that semen cooled for 24 hours at 5ºC.Anais do 15o. Simpósio Paranaense de Ovinocultura, 3o. Simpósio Paranaense de Caprinocultura, 3o. Simpósio Sul Brasileiro de Ovinos e Caprinos, Pato Branco, PR, out., 2011
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