Efecto de los grados día de ayuno y del hacinamiento previos al sacrificio sobre el contenido estomacal y respuesta de estrés en trucha arcoíris (Oncorhynchus mykiss)

El ayuno pre-sacrificio es una práctica rutinaria en acuicultura que se lleva a cabo para vaciar el aparato digestivo disminuyendo la cantidad de heces y previniendo una contaminación de la canal (Robb, 2008). Sin embargo, el ayuno puede también incrementar los niveles de estrés de los peces y si estos son lo suficientemente altos afectan a la calidad de la canal (Poli et al., 2005)

Olive classification according to external damage using image analysis.

The external appearance of an olive’s skin is the most decisive factor in determining its quality as a fruit. This work tries to establish a hierarchical model based on the features extracted from images of olives reflecting their external defects. Seven commercial categories of olives, established by product experts, were used: undamaged olives, mussel-scale or ‘serpeta’, hail-damaged or ‘granizo’, mill or ‘rehús’, wrinkled olive or ‘agostado’, purple olive and undefined-damage or ‘molestado’. The original images were processed using segmentation, colour parameters and morphological features of the defects and the whole fruits. The application of three consecutive discriminant analyses resulted in the correct classification of 97% and 75% of olives during calibration and validation, respectively. However the correct classification percentages vary greatly depending on the categories, ranging 80–100% during calibration and 38– 100% during validation

Respuesta agronómica de diferentes cultivares tintos de vid en zona templada

Se presenta la respuesta varietal de 6 cultivares tintos de vid, con riego deficitario controlado, en zona cálida: Barbera, Graciano, Mencía, Pinot noir, Petit verdot y Tempranillo. Teniendo en cuenta que en zona cálida hay que escoger cultivares de ciclo largo, recolección tardía, capaces de madurar manteniendo alta la acidez real y total, se concluye que los más idóneos para su cultivo en zona cálida son Barbera, por su alta acidez y Petit verdot y Graciano por su larga maduración y acidez equilibrada. Tempranillo, si bien en este trabajo presenta una respuesta adecuada, para equivalente maduración sacarimétrica a las anteriores posee menor acidez e IPT. Mencía madura mejor en situaciones frescas que en zona cálid

Determination of the basic friction angle ϕb of joints using the field tilt test: results of various "fast" tests on outcrops

The basic friction angle of rock joints is usually obtained from tilt tests, being the most common the laboratory tilt tests. This test has been standardized according to the ISRM. However, most of the times when calculating the shear strength of discontinuities, reference tables are used to obtain the basic friction value for the lithology under study. These tables omit some lithologies complicating the search of adequate references. An alternative, straightforward and economical way to obtain ϕb is through the field tilt test, which is carried out by sliding two blocks aside a joint. It is a well-known test, but there are few references to its implementation. In this test, unlike the laboratory tilt test, the samples are not "polished" and it is necessary to evaluate the roughness of the joint and the normal component to the weight of the upper blocks. The idea is to calculate the term of ϕb from the Barton-Bandis' equation and include the tilt angle α. Various tilt-test measurements were carried out with field blocks on both sides of the same joint, considering different lithologies (granite, limestone, andesite, dacite, coal and slate) and block sizes, evaluating the ideal ranges of applicability of the test

Stable Isotopes and Archaeology in Central Chile: Methodological Insights and Interpretative Problems for Dietary Reconstruction

This paper discusses the problems faced when making interpretations of human stable isotope values due to the various explanatory alternatives that arise when reading archaeological data. These interpretative issues are analysed and discussed using the isotopic results for approximately 100 human individuals from archaeological contexts spanning from 5000 BC to 1540 AD in central Chile, supported by data for more than 50 plant and animal samples to establish a local C3 and C4 baseline. A number of assumptions are frequently used to establish the bridge between isotopic results in human tissues and their corresponding diets. The problem is that different assumptions lead to different dietary reconstructions. Past feeding experiments on herbivores, pigs, rats and mice give different results, so we need to be cautious when applying these models to human isotope data. One specific problem concerns estimates of % C4 from collagen and apatite data, a very important issue when looking for evidence of maize in archaeological contexts, which was one of the major objectives we had in the isotopic analyses of archaeological specimens in central Chile. We conclude that the opportunity for estimating the actual percentage of C4 foods in human diets is limited, since a specific apatite fractionation value for humans cannot be experimentally determined, while maize consumption is underrepresented in bone collagen. This may be addressed in our study by sampling more specimens of wild gramineae to establish baseline plant values, more humans that could have had a low maize intake, and more Archaic period individuals when there was certainly no maize in the region

The effect of intermittent feeding on the pre-slaughter fasting response in rainbow trout

Pre-slaughter fasting, usually measured in days, helps to empty the digestive system but less is known about its effect on fish welfare or flesh quality. We evaluated the combined effects of fasting (measured in degree-days, °C d), preceded by intermittent feeding in the last month of production, on the flesh quality rainbow trout (Oncorhynchus mykiss). Trout (n = 240) were fed the same total amount of food either daily (D), once every two days (2D) or once every four days (4D) for one month, and then fasted for 24.3 °C d (2 days) or 102 °C d (9 days). There was a significant interaction between the effects of intermittent feeding and pre-slaughter fasting for most of the parameters measured. Slaughter weight was higher in 2D and 4D trout after two days of fasting, probably since they had more feed in their stomachs. Muscle glycogen and the hepato-somatic index were also higher in 2D trout after 2 days of fasting, suggesting higher energy reserves. There was no interaction between the effects of intermittent feeding and fasting on final muscle pH which was higher after 9 days of fasting, indicating poorer flesh quality. Overall, the results suggest that trout that received a skip-a-day feeding schedule one month before slaughter, adapt better to a two day fast than trout fed daily or once every four days

Measurement and Study on Drying Shrinkage Characteristic of Tobacco Lamina Based on Computer Vision

International audienceAccurate evaluation of shrinkage characteristic for tobacco lamina during drying process is important for optimizing tobacco primary process. The present work developed a detection and characterization method of shrinkage characteristic based on computer vision. Effect of types and dimensions of tobacco lamina on the shrinkage characteristic were investigated and shrinkage rate variation at different drying stages was also analyzed by this method. The results show that percentage reduction of area, which is obtained by detecting tobacco lamina area before and after drying, can be used to reflect the shrinkage characteristic of tobacco lamina. RSD of measurement results by this method is less than 6% under test conditions. Compared with upper tobacco leaf, middle tobacco leaf shows the higher shrinkage rate of 14.3%. Dimensions of tobacco lamina also have significant effect on its shrinkage characteristic. The larger size (up 30mm mesh) tobacco lamina shows a higher shrinkage rate. Shrinkage rate of tobacco lamina is closely related to moisture content variation during drying. The shrinkage of tobacco lamina during drying mainly occurs within the moisture content range of 20% to 14%

Functional Characterization and Localization of the Aspergillus nidulans Formin SEPA

Formins are a family of multidomain scaffold proteins involved in actin-dependent morphogenetic events. In Aspergillus nidulans, the formin SEPA participates in two actin-mediated processes, septum formation and polarized growth. In this study, we use a new null mutant to demonstrate that SEPA is required for the formation of actin rings at septation sites. In addition, we find that a functional SEPA::GFP fusion protein localizes simultaneously to septation sites and hyphal tips, and that SEPA colocalizes with actin at each site. Using live imaging, we show that SEPA localization at septation sites and hyphal tips is dynamic. Notably, at septation sites, SEPA forms a ring that constricts as the septum is deposited. Moreover, we demonstrate that actin filaments are required to maintain the proper localization pattern of SEPA, and that the amino-terminal half of SEPA is sufficient for localization at septation sites and hyphal tips. In contrast, only localization at septation sites is affected by loss of the sepH gene product. We propose that specific morphological cues activate common molecular pathways to direct SEPA localization to the appropriate morphogenetic site