987 resultados para pre-image attack


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Una abundancia masiva de pre-adultos de la concha de abanico se observó en la zona de Pisco a fines de abril de 1983, dando lugar a un considerable aumento de su explotación en los meses siguientes. Para conocer el tiempo que esta especie necesita para reclutarse a la pesquería, el crecimiento de pre-adultos muy pequeños (promedio de 8,2 mm) fue observado en una bandeja de fondo durante las estaciones de otoño e invierno en 1983. Después de 110 días, las conchas alcanzaron el tamaño mínimo permitido (55 mm) indicando un crecimiento muy rápido en comparación a otros pectínidos.

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The nuptial flight allows males and females to meet and copulate and both need energy to perform this activity. Before leaving the nest, males and females are well nourished and ready to mate. However, little is known about the lipid and energy contents in females before the nuptial flight (virgins) and after it (mated females). In this work we measured lipid concentrations in relation to body weight in these individuals. Our results showed that 16.82% of the bodies of young virgin females one month before mating flight are composed of lipids, contrasting with the 32.62% lipid content in mated females who had not excavated their nest yet, and 32.88% in those who had. The energy content measured for virgin females was 2942.63 J, contrasting with 6110.01 J for queens before excavating the nest and 5677.51 J after excavation. Based on our results, we conclude that the body mass, and therefore the lipid and energy contents in the bodies of Atta sexdens rubropilosa queens double during the last month before the nuptial flight. This energy resource is fundamental to the activities required during the nuptial flight, digging the nest and the founding of the colony.

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Does the aggressiveness of the prey modify the attack behavior of the predator Supputius cincticeps (Stål) (Hemiptera, Pentatomidae)? The stink bug Supputius cincticeps (Stål) (Hemiptera, Pentatomidae) is a predator found in several Brazilian regions, which possesses desirable attributes as a natural control agent and in biological control programs. The aim of this study was to test if the attack behavior and predation success of S. cincticeps were affected by prey species. Larvae of Tenebrio molitor (L.) (Coleoptera, Tenebrionidae), Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae), and Thyrinteina arnobia (Stoll) (Lepidoptera, Geometridae) were offered to S. cincticeps in laboratory bioassays where predatory attack and prey defensive behaviors were observed for 2-hour periods. The attack behavior of S. cincticeps changed with the prey species offered. More than 25% of T. molitor and S. frugiperda larvae were immediately attacked, but T. arnobia was not immediately attacked by S. cincticeps. Successful attack (i.e., successful insertion of the predator stylets into the prey) depends on the region of the body attacked, with a greater proportion of successful attacks in the anterior than in the median or posterior regions. Larvae of T. arnobia and S. frugiperda displayed a sequence of abrupt head and body movements in response to S. cincticeps attack. Attempts of predation were more successful on T. molitor and S. frugiperda than on T. arnobia. Information about the differential attack behavior of S. cincticeps on different prey species is important for designing successful biological control programs using this hemipteran predator.

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The differentiation between benign and malignant focal liver lesions plays an important role in diagnosis of liver disease and therapeutic planning of local or general disease. This differentiation, based on characterization, relies on the observation of the dynamic vascular patterns (DVP) of lesions with respect to adjacent parenchyma, and may be assessed during contrast-enhanced ultrasound imaging after a bolus injection. For instance, hemangiomas (i.e., benign lesions) exhibit hyper-enhanced signatures over time, whereas metastases (i.e., malignant lesions) frequently present hyperenhanced foci during the arterial phase and always become hypo-enhanced afterwards. The objective of this work was to develop a new parametric imaging technique, aimed at mapping the DVP signatures into a single image called a DVP parametric image, conceived as a diagnostic aid tool for characterizing lesion types. The methodology consisted in processing a time sequence of images (DICOM video data) using four consecutive steps: (1) pre-processing combining image motion correction and linearization to derive an echo-power signal, in each pixel, proportional to local contrast agent concentration over time; (2) signal modeling, by means of a curve-fitting optimization, to compute a difference signal in each pixel, as the subtraction of adjacent parenchyma kinetic from the echopower signal; (3) classification of difference signals; and (4) parametric image rendering to represent classified pixels as a support for diagnosis. DVP parametric imaging was the object of a clinical assessment on a total of 146 lesions, imaged using different medical ultrasound systems. The resulting sensitivity and specificity were 97% and 91%, respectively, which compare favorably with scores of 81 to 95% and 80 to 95% reported in medical literature for sensitivity and specificity, respectively.

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Microparticles are phospholipid vesicles shed mostly in biological fluids, such as blood or urine, by various types of cells, such as red blood cells (RBCs), platelets, lymphocytes, endothelial cells. These microparticles contain a subset of the proteome of their parent cell, and their ready availability in biological fluid has raised strong interest in their study, as they might be markers of cell damage. However, their small size as well as their particular physico-chemical properties makes them hard to detect, size, count and study by proteome analysis. In this review, we report the pre-analytical and methodological caveats that we have faced in our own research about red blood cell microparticles in the context of transfusion science, as well as examples from the literature on the proteomics of various kinds of microparticles.