130 research outputs found

    The Target Silicon Detector for the FOCUS Spectrometer

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    We describe a silicon microstrip detector interleaved with segments of a beryllium oxide target which was used in the FOCUS photoproduction experiment at Fermilab. The detector was designed to improve the vertex resolution and to enhance the reconstruction efficiency of short-lived charm particles.Comment: 18 pages, 14 figure

    Shaping of a three-dimensional carnivorous trap through modulation of a planar growth mechanism

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    Leaves display a remarkable range of forms, from flat sheets with simple outlines to cup-shaped traps. Although much progress has been made in understanding the mechanisms of planar leaf development, it is unclear whether similar or distinctive mechanisms underlie shape transformations during development of more complex curved forms. Here, we use 3D imaging and cellular and clonal analysis, combined with computational modelling, to analyse the development of cup-shaped traps of the carnivorous plant Utricularia gibba. We show that the transformation from a near-spherical form at early developmental stages to an oblate spheroid with a straightened ventral midline in the mature form can be accounted for by spatial variations in rates and orientations of growth. Different hypotheses regarding spatiotemporal control predict distinct patterns of cell shape and size, which were tested experimentally by quantifying cellular and clonal anisotropy. We propose that orientations of growth are specified by a proximodistal polarity field, similar to that hypothesised to account for Arabidopsis leaf development, except that in Utricularia, the field propagates through a highly curved tissue sheet. Independent evidence for the polarity field is provided by the orientation of glandular hairs on the inner surface of the trap. Taken together, our results show that morphogenesis of complex 3D leaf shapes can be accounted for by similar mechanisms to those for planar leaves, suggesting that simple modulations of a common growth framework underlie the shaping of a diverse range of morphologies

    Macro optical projection tomography for large scale 3D imaging of plant structures and gene activity

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    Optical projection tomography (OPT) is a well-established method for visualising gene activity in plants and animals. However, a limitation of conventional OPT is that the specimen upper size limit precludes its application to larger structures. To address this problem we constructed a macro version called Macro OPT (M-OPT). We apply M-OPT to 3D live imaging of gene activity in growing whole plants and to visualise structural morphology in large optically cleared plant and insect specimens up to 60 mm tall and 45 mm deep. We also show how M-OPT can be used to image gene expression domains in 3D within fixed tissue and to visualise gene activity in 3D in clones of growing young whole Arabidopsis plants. A further application of M-OPT is to visualise plant-insect interactions. Thus M-OPT provides an effective 3D imaging platform that allows the study of gene activity, internal plant structures and plant-insect interactions at a macroscopic scale

    Inclusion of cocoa by-product in the diet of dairy sheep: Effect on the fatty acid profile of ruminal content and on the composition of milk and cheese.

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    Abstract In this study, we hypothesized that dietary cocoa bean shell (CBS) as a partial replacer of human edible cereal grains in the diet of lactating ewes may affect performance and milk and cheese composition. Twenty Comisana lactating ewes allotted into control (CTRL; n = 10) or cocoa (CBS; n = 10) group received alfalfa hay ad libitum and 800 g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Milk yield and composition did not differ between groups, and only urea concentration was lower in CBS milk. Dietary CBS increased cheese fat and reduced protein percentage in CBS group. Fatty acid composition of rumen content partially reflected that of the ingested diet, with total saturated fatty acids (SFA), total monounsaturated fatty acids (MUFA), 16:0, 18:0 and 18:1c9 greater in the CBS group. Moreover, all the identified trans- and cis-18:1 isomers were greater in CBS rumen content. Milk and cheese showed a similar fatty acid composition. Total MUFAs were greater in milk and cheese of CBS, mainly due to the proportion of 18:1c9, and conversely, total polyunsaturated fatty acids (PUFA), PUFAn-6 and PUFAn-6-to-PUFAn-3 ratio was greater in CTRL group. Concluding, the inclusion of CBS in the diet of lactating ewes within the limit imposed by the current legislation did not cause detrimental effects on animal performance and milk composition. Interestingly, dietary CBS reduced milk urea concentration probably due to the phenols contained in CBS concentrate. However, our results support that biohydrogenation was weakly impaired by dietary CBS. Finally, CBS negatively affected cheese nutritional characteristics due to lower protein and greater fat content, but improved fat health indexes in milk and cheese

    Fibroblasts from patients with Diamond-Blackfan anaemia show abnormal expression of genes involved in protein synthesis, amino acid metabolism and cancer

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    Background: Diamond-Blackfan anaemia (DBA) is a rare inherited red cell hypoplasia characterised by a defect in the maturation of erythroid progenitors and in some cases associated with malformations. Patients have an increased risk of solid tumors. Mutations have been found in several ribosomal protein (RP) genes, i.e RPS19, RPS24, RPS17, RPL5, RPL11, RPL35A. Studies in haematopoietic progenitors from patients show that haplo-insufficiency of an RP impairs rRNA processing and ribosome biogenesis. DBA lymphocytes show reduced protein synthesis and fibroblasts display abnormal rRNA processing and impaired proliferation. Results: To evaluate the involvement of non-haematopoietic tissues in DBA, we have analysed global gene expression in fibroblasts from DBA patients compared to healthy controls. Microarray expression profiling using Affymetrix GeneChip Human Genome U133A 2.0 Arrays revealed that 421 genes are differentially expressed in DBA patient fibroblasts. These genes include a large cluster of ribosomal proteins and factors involved in protein synthesis and amino acid metabolism, as well as genes associated to cell death, cancer and tissue development. Conclusion: This analysis reports for the first time an abnormal gene expression profile in a non-haematopoietic cell type in DBA. These data support the hypothesis that DBA may be due to a defect in general or specific protein synthesis. \ua9 2009 Avondo et al; licensee BioMed Central Ltd

    Efeito da tosquia na temperatura corpórea e outros parâmetros clínicos em ovinos

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    The aim of this study was to determine the variation of the temperature after shearing in sheep under dry and hot environment conditions and to compare the temperature changes with variation in cardiac and respiratory frequencies, ruminal movements and hydration status. Twenty Suffolk unshorn ewes were studied. Physical examination was performed in all animals three times a day at 7:00 AM, 1:00 PM and 7:00 PM, during 42 days (22 days before shearing and 20 days after shearing). The skin temperature was measured by infrared thermometer over several surfaces of the body. Data were submitted to analysis of variance, for comparisons between groups (shorn versus unshorn) at each time, and the significant difference was evaluated at level of P<0.05 by Tukey test. The respiratory frequency was statistically significant at all times. When air humidity was high, the respiratory frequencies were low. The thermal stress was clear in sheep of this study, reflecting marked changes in cardiac and respiratory frequencies and rectal temperature. The respiratory frequency was the parameter more reliable to establish a framework of thermal stress in the unshorn sheep, with values on average three times higher than those reported in the literature. The heart rate monitors the thermal variation of the environment and is also an indicator of heat stress. This variation shows the Suffolk breed is well adapted to hot climates. The correlation between the body surface temperatures with environment temperature and air humidity was negative, as explained by the effect of wool insulation, i.e. even with an increase in environment temperature and humidity, the body temperature tends to maintain a compensating balance. In the shorn animals, the correlation between skin temperature with environment temperature and air humidity showed that the skin temperature increases when the environment temperature increases. The increase in the environment temperature does not affect the body temperature of unshorn animals due the insulating effect of the wool. However, when environment temperature rises, the presence of the wool starts to affect the thermal comfort as the heat absorption is larger than the capacity of heat loss. In this study, the best thermal stress indicators were the respiratory frequency and rectal and skin temperatures. The temperatures of the skin measured at the perineum, axillae and inner thigh were considered the most reliable.Departamento de Clínica, Cirurgia e Reprodução Animal Faculdade de Medicina Veterinária (FMVA) Universidade Estadual Paulista (Unesp), Rua Clóvis Pestana 793, Araçatuba, SP 16050-680Departamento de Apoio Produção e Saúde Animal FMVA-Unesp, Araçatu-çatuba, SP 16050-680Departamento de Clínica, Cirurgia e Reprodução Animal Faculdade de Medicina Veterinária (FMVA) Universidade Estadual Paulista (Unesp), Rua Clóvis Pestana 793, Araçatuba, SP 16050-680Departamento de Apoio Produção e Saúde Animal FMVA-Unesp, Araçatu-çatuba, SP 16050-68

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