Feno de cunhã (Clitoria ternatea L.) para acabamento de cordeiros.

Resumo: Foram utilizados 32 cordeiros, mestiços, durante setenta dias em estudo na Embrapa Caprinos, em Sobral, CE, para determinar a influência do nível de concentrado em dietas para acabamento de cordeiros em confinamento. Os tratamentos foram as seguintes relaçoes forragem:concentrado: 100%:0% (T1), 85%:15% (T2), 70%:30% (T3) e 55%:45% (T4). A forragem fornecida era feno de cunha e o concentrado era composta de 75% de milho e 25% de farelo de soja. 0 ajuste das proporçoes foi feito diariamente, corn base no consumo de volumoso, servido ad libitum. Corn o aumento do nível de concentrado na dieta dos animais, observou-se incrementos lineares (PO,05) quanto aos tratamentos. Conclui-se que todas as raçoes testadas podem ser utilizadas para terminação de cordeiros em confinamento. Cunhã hay (Clitoria ternatea L.) for finishing of lambs. ABSTRACT - Thirty two crossbred lambs were used in a 70 day study at Embrapa Caprinos, in Sobral, CE, Brazil to evaluate the influence of concentrate levels on finishing diets under confinement. The treatments were the following roughage to concentrate relations: 100% to 0% (T1), 85% to 15% (T2), 70% to 30% (T3) and 55% to 45% (T4). The roughage was cunhã hay (Clitoria ternatea L), and the concentrate was composed of corn (75%) and soybean meal (25%). The adjustments of the proportions were made daily, based on the roughage intake, served ad libitum. It was observed that the total dry matter intake increased, the forage intake decreased, the feed efficiency improved and the daily weight gain increased (P0.05) among treatments. It was concluded that any of the diets studied can be used for finishing lambs

Near-tip analysis of crack propagation in cementitious composites

The fracture process zone encloses relevant mechanisms which explain the quasi-brittle behavior of cementitious composites. It is an important concept in non-linear fracture mechanics and in the simulation of cracking processes. The use of fibers as reinforcement may alter the crack initiation and propagation processes. A better understanding of the micro-cracking mechanisms taking place at the level of the fracture process zone is therefore relevant for an optimized design of these materials, as well as for the simulation of their mechanical behavior. In this study, the use of an image analysis procedure to capture the crack initiation and propagation process in concrete and other cementitious composites is described. It utilizes high resolution digital images of the surface of the specimens while undergoing the cracking process to determine the displacement fields. The formed cracks are observed at a relatively small scale, allowing the investigation and analysis of propagating cracks near the crack tip in specimens of concrete and other cementitious composites.Fundação para a Ciência e a Tecnologia (FCT

Constraining planet structure and composition from stellar chemistry: trends in different stellar populations

The chemical composition of stars that have orbiting planets provides important clues about the frequency, architecture, and composition of exoplanet systems. We explore the possibility that stars from different galactic populations that have different intrinsic abundance ratios may produce planets with a different overall composition. We compiled abundances for Fe, O, C, Mg, and Si in a large sample of solar neighbourhood stars that belong to different galactic populations. We then used a simple stoichiometric model to predict the expected iron-to-silicate mass fraction and water mass fraction of the planet building blocks, as well as the summed mass percentage of all heavy elements in the disc. Assuming that overall the chemical composition of the planet building blocks will be reflected in the composition of the formed planets, we show that according to our model, discs around stars from different galactic populations, as well as around stars from different regions in the Galaxy, are expected to form rocky planets with significantly different iron-to-silicate mass fractions. The available water mass fraction also changes significantly from one galactic population to another. The results may be used to set constraints for models of planet formation and chemical composition. Furthermore, the results may have impact on our understanding of the frequency of planets in the Galaxy, as well as on the existence of conditions for habitability.Comment: Accepted for publication in Astronomy & Astrophysic

Distinguishing the albedo of exoplanets from stellar activity

Light curves show the flux variation from the target star and its orbiting planets as a function of time. In addition to the transit features created by the planets, the flux also includes the reflected light component of each planet, which depends on the planetary albedo. This signal is typically referred to as phase curve and could be easily identified if there were no additional noise. As well as instrumental noise, stellar activity, such as spots, can create a modulation in the data, which may be very difficult to distinguish from the planetary signal. We analyze the limitations imposed by the stellar activity on the detection of the planetary albedo, considering the limitations imposed by the predicted level of instrumental noise and the short duration of the observations planned in the context of the CHEOPS mission. As initial condition, we have assumed that each star is characterized by just one orbiting planet. We built mock light curves that included a realistic stellar activity pattern, the reflected light component of the planet and an instrumental noise level, which we have chosen to be at the same level as predicted for CHEOPS. We then fit these light curves to try to recover the reflected light component, assuming the activity patterns can be modeled with a Gaussian process.We estimate that at least one full stellar rotation is necessary to obtain a reliable detection of the planetary albedo. This result is independent of the level of noise, but it depends on the limitation of the Gaussian process to describe the stellar activity when the light curve time-span is shorter than the stellar rotation. Finally, in presence of typical CHEOPS gaps in the simulations, we confirm that it is still possible to obtain a reliable albedo.Comment: Accepted for publication in A&A, 14 pages, 12 figure

Parâmetros de qualidade tecnológica de grãos em seis genótipos de feijão-caupi cultivados em regime irrigado.

O presente trabalho foi conduzido na Embrapa Semi-Árido, em Petrolina, PE, com o objetivo de avaliar a qualidade tecnológica em genótipos de feijão-caupi em regime irrigado. Foram avaliadas as seguintes variáveis: porcentagem de embebição de água antes do cozimento (PEANC), porcentagem de embebição de água após o cozimento (PEAPC), determinação da taxa de expansão volumétrica dos grãos após o cozimento (EV) e porcentagem de grãos inteiros após o cozimento (PGI). Os quadrados médios de tratamento foram significativos (p<0,05) pelo teste F para as variáveis PEANC e PGI. O 'Canapu' apresentou o maior valor para PEANC, deferindo significativamente dos demais tratamentos. A variável PEANC variou de 116,8% a 134,3%. A PEAPC variou de 78,7% a 90,3%, tendo sido maior para a linhagem PC 95-05-12-2-2, que diferiu significativamente da cultivar IPA 206. Apenas a correlação fenotípica entre Peapc x EV foi significativa, tendo sido negativa. No geral, estes resultados são indicativos de que as linhagens selecionadas na Embrapa Semi-Árido apresentam qualidade tecnológica de grãos aceitáveis pelo mercado, sendo que um esforço maior deverá ser enfatizado no sentido de elevar a porcentagem de embebição antes do cozimento para níveis próximos ao 'Canapu', que é um tipo bastante aceito pelo mercado