Objective assessment of the cryoprotective effects of dimethylformamide for freezing goat semen

AbstractThe aim of this work was to assess the cryoprotective effects of dimethylformamide (DMF) for freezing goat semen, using an objective analysis by computer-assisted sperm analysis (CASA). Twenty-one ejaculates (seven per animal) were collected from three stud bucks with the aid of an artificial vagina and immediately evaluated for gross and microscopic characteristics. The semen was diluted in two steps with a Tris–egg yolk extender containing 6% glycerol or 6% DMF, frozen in 0.50-mL straws, and stored in liquid nitrogen. Samples were accessed for sperm morphology, sperm membrane structural and functional integrity, and by CASA, immediately after thawing. There were differences (P<0.05) between glycerol and DMF with regard to subjective progressive motility (23.9±2.2% vs. 16.6±2.0%), objective progressive motility (3.5±0.4% vs. 1.8±0.3%), linearity (53.9±1.6% vs. 48.1±1.4%) and amplitude of lateral head (2.3±0.1 vs. 2.9±0.1mm), which confirmed the efficiency of glycerol. In conclusion, dimethylformamide could be used as an alternative cryoprotectant for goat semen freezing. However it was showed that no benefits were derived by using dimethylformamide to replace glycerol at an equal 6% concentration

De Sitter Cosmic Strings and Supersymmetry

We study massive spinor fields in the geometry of a straight cosmic string in a de Sitter background. We find a hidden N=2 supersymmetry in the fermionic solutions of the equations of motion. We connect the zero mode solutions to the heat-kernel regularized Witten index of the supersymmetric algebra.Comment: Version similar to the one accepted by General Relativity and Gravitatio

Wormhole geometries with conformal motions

Exact solutions of traversable wormholes were recently found under the assumption of spherical symmetry and the existence of a non-static conformal symmetry. In this paper, we verify that in the case of the conformally symmetric spacetimes with a non-static vector field generating the symmetry, the conformal factor $\psi$ can be physically interpreted in terms of a measurable quantity, namely, the tangential velocity of a massive test particle moving in a stable circular orbit in the spacetime. Physical properties of the rotational velocity of test particles and of the redshift of radiation emitted by ultra-relativistic particles rotating around these hypothetical general relativistic objects are further discussed. Finally, specific characteristics and properties of gravitational bremsstrahlung emitted by charged particles in geodesic motion in conformally symmetric wormhole geometries are also explored.Comment: 7 pages. V2: clarifying comments added, to appear in Classical and Quantum Gravit

Adsorption of CO2 on Amine-Grafted Activated Carbon

Adsorption on amine-grafted materials may be a potentially attractive alternative to capturing CO2 from power plants. Activated Carbon (AC) has been proposed as a potential adsorbent due to its natural affinity for CO2 and to the possibility of tailoring textural properties and surface chemistry to enhance capacity and selectivity. An AC commercial sample was functionalized with monoethanolamine (MEA) in order to obtain nitrogen-enriched AC with two different loadings (ACN10 and ACN20). Samples characterization was carried out by nitrogen adsorption/desorption isotherms at 77 K, XPS, FTIR and adsorption microcalorimetry. CO2 equilibrium adsorption experiments were accomplished in a volumetric system in the pressure range of vacuum up to 10 bar, at 298 and 348 K. Impregnated activated carbon presented different chemical and textural characteristics with a significant reduction in the surface area, depending on the amine loading. A high adsorption capacity at room temperature and high pressure was observed for the pristine AC as compared to the modified samples. The reduction in surface area affected the adsorption capacity of CO2 at 298 and 348 K, except for adsorption on ACN10 at 348 K, which suggests the occurrence of chemisorption.Fil: Bezerra, Diôgo P.. Universidade Federal do Ceara. Department of Chemical Engineering. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Da Silva, Francisco W. M.. Universidade Federal do Ceara. Department of Chemical Engineering. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: de Moura, Pedro A. S.. Universidade Federal do Ceara. Department of Chemical Engineering. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Vieira, Rodrigo S.. Universidade Federal do Ceara. Department of Chemical Engineering. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Rodriguez Castellon, Enrique. Universidad de Malaga. Facultad de Ciencias; EspañaFil: de Azevedo, Diana C. S.. Universidade Federal do Ceara. Department of Chemical Engineering. Grupo de Pesquisa em Separações por Adsorção; Brasi

Linking shifts in bacterial community with changes in dissolved organic matter pool in a tropical lake

Bacterioplankton communities have a pivotal role in the global carbon cycle. Still the interaction between microbial community and dissolved organic matter (DOM) in freshwater ecosystems remains poorly understood. Here, we report results from a 12-day mesocosm study performed in the epilimnion of a tropical lake, in which inorganic nutrients and allochthonous DOM were supplemented under full light and shading. Although the production of autochthonous DOM triggered by nutrient addition was the dominant driver of changes in bacterial community structure, temporal covariations between DOM optical proxies and bacterial community structure revealed a strong influence of community shifts on DOM fate. Community shifts were coupled to a successional stepwise alteration of the DOM pool, with different fractions being selectively consumed by specific taxa Typical freshwater clades as Limnohabitans and Sporichthyaceae were associated with consumption of low molecular weight carbon, whereas Gammaproteobacteria and Flavobacteria utilized higher molecular weight carbon, indicating differences in DOM preference among Glades. Importantly. Verrucomicrobiaceae were important in the turnover of freshly produced autochthonous DOM, ultimately affecting light availability and dissolved organic carbon concentrations. Our findings suggest that taxonomically defined bacterial assemblages play definite roles when influencing DOM fate, either by changing specific fractions of the DOM pool or by regulating light availability and DOC levels. (C) 2019 Elsevier B.V. All rights reserved.Peer reviewe

Índice de sustentabilidade agroambiental para o perímetro irrigado Ayres de Souza.

Uma análise integrada do atual uso dos recursos naturais do Perímetro Irrigado de Ayres de Souza, localizado no Vale do Acaraú, Ceará, foi realizada através do desenvolvimento de um índice de sustentabilidade agroecológica. Os dados dessa pesquisa foram oriundos de questionários aplicados a 33 produtores agrícolas beneficiados pelo projeto de irrigação. Os indicadores de sustentabilidade foram estimados pelo emprego de análise fatorial, método da análise fatorial/análise de componentes principais. O índice de sustentabilidade estimado a partir dos indicadores selecionados registrou uma situação de sustentabilidade fragilizada ou de insustentabilidade reversível. As unidades produtivas apresentaram um porcentual de 60,6% com alguma sustentabilidade; e os demais 39,4% estão em condições de insustentabilidade. Os resultados também mostraram que os fatores dominantes do índice de sustentabilidade foram: nível da atividade agrícola praticada, agricultura familiar, condições atuais do sistema água-solo e infraestrutura,fontes alternativas de renda e experiência em tratos culturais

Morphology and biomass of sunflower plants grown under water deficits in different development stages

The objective of the present study was to evaluate the morphology, biomass production and biomass partition of sunflower (Multissol cultivar) when subjected to water deficit at Pentecoste, CE - Brazil. An experimental design in randomized blocks was used as split plots in time (8 x 3) with four replications, with the treatments defined by the development stage for application of water deficit vegetative, flowering and formation of production stages corresponding to the occurrence of water deficit at stages 1, 2 or 3 and three evaluation periods at 52, 68 and 110 days after sowing. The plant height, number of leaves and stem diameter were negatively influenced by the isolated effects of the water deficits and evaluation periods. The water deficits and evaluation periods interacted and affected the leaf area, dry mass of leaves, petiole, stem, head and total. The best response in terms of growth and biomass production occurred in the treatment presenting no water deficit throughout the cycle. The irrigation deficits did not change the biomass partition. The irrigation level equivalent to 50% of the ETo compromised morphology and biomass production, when applied at any development stage.Objetivou-se, com este trabalho, avaliar a morfologia, a produção e a partição de fitomassa do girassol cv. Multissol quando submetido a déficits de irrigação em Pentecoste, CE. Utilizou-se o delineamento estatístico em blocos ao acaso, em esquema de parcelas subdivididas no tempo (8 x 3), com quatro repetições, sendo os tratamentos definidos em função da época de indução do déficit de irrigação nos estádios vegetativo, floração e formação da produção, correspondendo à ocorrência de déficit hídrico em 1, 2 ou 3 estádios e três épocas de avaliação (aos 52, 68 e 110º dia após a semeadura). A altura da planta, o número de folhas e o diâmetro do caule foram negativamente afetados pelos efeitos isolados dos déficits de irrigação e das épocas de avaliação. Os déficits de irrigação e as épocas de avaliação interagiram e afetaram a área foliar, a massa seca da folha, do pecíolo, do caule, do capítulo e total. A melhor resposta em ganhos de crescimento e de produção de fitomassa deu-se no tratamento sem déficit de irrigação, em todo o ciclo. Os déficits de irrigação não modificaram a partição de fitomassa. O nível de irrigação equivalente a 50% da ETo comprometeu a morfologia e a produção de fitomassa quando aplicado em qualquer estádio de desenvolvimento.95996

Acyloxylation of Cyclic Enones: Synthesis of Densely Oxygenated Guaianolides

The α′-acyloxylation of cyclic enones with linear carboxylic acids is described. The reaction is promoted by KMnO4 in the presence of a carboxylic acid and its corresponding carboxylic anhydride. The optimization of the reaction has been carried out using the statistical methodology known as design of experiments. The optimized reaction conditions have been evaluated in terms of substrate scope and compatibility with different functional groups. The methodology has been applied to the synthesis of densely oxygenated guaianes and guaianolides

Reply to: Shark mortality cannot be assessed by fishery overlap alone

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