Study of a precise positioning system of the COMSS Altimetric Satellite/Radar

A satellite trajectory was reconstructed at an accuracy level of 5-10 centimeters. The reconstruction of the orbit at a level of 1 to 2 meters, and comparison of all results for the two altitudes, 650 and 850 km, are also considered

Ionic conductivity of an extruded Nafion 1100 EW series of membranes

The proton conductivity of a series of extruded Nafion membranes @of equivalent weight ~EW! of 1100 and nominal dry thickness of 51, 89, 127, and 178 mm# has been studied. Measurements were made in 1 M H2SO4 at 298 K using a four-electrode, dc technique. The membrane area resistance increases with thickness, as expected, from 0.07 to 0.16 V cm2 for Nafion 112 and Nafion 117, respectively. However, in contrast to the published literature, after correcting for the membrane thickness, the conductivity of the membranes decreases with decreasing membrane thickness. For example, values of 0.083 and 0.16 S cm21 were obtained for Nafion 112 and 117 membranes, respectively. In situ current-interrupt measurements in a proton exchange membrane fuel cell confirmed the relatively poor conductivity of the membrane electrode assemblies ~MEAs! based on the thinner membranes. While a high contact resistance to the electrodes may have contributed to the in situ MEA resistance, water balance measurements over the MEA showed that the high resistance was not due to a low water content or to an uneven water distribution in the MEAs. The implications of the findings for the understanding of the membrane properties are discussed

Test of a downstream migration device for atlantic salmon juveniles (1993): hydroelectric power plant of Soeix (Gave d'Aspe - 64)

Second campaign of experiments conducted in the hydroelectrical power plant of Soeix on the Gave d'Aspe (64) to test the efficiency of a delivery valve used as downstream outlet. / Deuxième campagne d'expérimentation conduite à la centrale hydroélectrique de Soeix sur le Gave d'Aspe (64) afin de tester l'efficacité d'un clapet de décharge utilisé comme exutoire de dévalaison

Fluorescent ligands for studying neuropeptide receptors by confocal microscopy

This paper reviews the use of confocal microscopy as it pertains to the identification of G-protein coupled receptors and the study of their dynamic properties in cell cultures and in mammalian brain following their tagging with specific fluorescent ligands. Principles that should guide the choice of suitable ligands and fluorophores are discussed. Examples are provided from the work carried out in the authors' laboratory using custom synthetized fluoresceinylated or BODIPY-tagged bioactive peptides. The results show that confocal microscopic detection of specifically bound fluorescent ligands permits high resolution appraisal of neuropeptide receptor distribution both in cell culture and in brain sections. Within the framework of time course experiments, it also allows for a dynamic assessment of the internalization and subsequent intracellular trafficking of bound fluorescent molecules. Thus, it was found that neurotensin, somatostatin and mu- and delta-selective opioid peptides are internalized in a receptor-dependent fashion and according to receptor-specific patterns into their target cells. In the case of neurotensin, this internalization process was found to be clathrin-mediated, to proceed through classical endosomal pathways and, in neurons, to result in a mobilization of newly formed endosomes from neural processes to nerve cell bodies and from the periphery of cell bodies towards the perinuclear zone. These mechanisms are likely to play an important role for ligand inactivation, receptor regulation and perhaps also transmembrane signaling

Consumo y digestibilidad aparente de raciones basadas en follaje de leguminosas tropicales arbóreas, paja de arroz amonificada y subproductos de maíz suministradas a cabras en confinamiento

The consumption and apparent digestibility of rations containing foliage of four arboreal legume species, Acacia macrantha (Am), A. tamarindifolia (At), A. glomerosa (Ag) and Leucaena leucocephala (Ll), in mixture with ammoniated rice straw (ARS) and corn byproducts meal (CBM), were evaluated using eight growing female Creole goats of mean body weights 20.5 kg, housed in metabolic stalls. The experimental design was an 8 x 8 latin square with a 4 x 2 factorial arrangement of the factors: 1) legume species and 2) level of foliage inclusion: 18.75 and 37.5% in the ration dry matter (DM). The experiment was divided into eight periods of 14 days each (7 for adaptation and 7 for measurement of consumption and total feces collection). The eight treatments (rations) included 25% (CBM) in all cases, and 56.25% ARS in combination with 18.75% foliage of Am, At, Ag, and Ll in T1, T3, T5 and T7; or 37.5% ARS in combination with 37.5% of the four respective legumes in T2, T4, T6, and T8. Rations containing AM (T1 + T2) and AG (T3 + T6) showed a tendency toward higher DM intake than T3 + T4 and T7 + T8 (1050 and 980 vs. 836 and 882 g/day), respectively, P<0.1011). Digestibility results followed the same pattern for DM (82 and 83 vs. 77 and 80%, P<0.008), fiber insoluble in acid detergent, and hemicellulose (HC). Rations with the lower level of legume combined, tended to give higher DM intake (987 vs. 889 g/day) and surpassed (P<0.05) those with higher legume level in digestibility of all the chemical fractions mentioned except HC.Se evaluó el consumo y digestibilidad aparente de raciones que incluyeron follaje de cuatro especies de leguminosas arbóreas, Acacia macrantha (Am), A. tamarindifolia (At), A. glomerosa (Ag) y Leucaena leucocephala (Ll), en mezcla con paja de arroz amonificada (PAA) y harina de subproductos de maíz (HSM), usando ocho cabras criollas en crecimiento, de peso promedio 20.5 kg, alojadas en jaulas metabólicas. El diseño experimental fue en cuadrado latino 8 x8 con un arreglo factorial 4 x 2 de los factores: 1) especie leguminosa y 2) nivel de inclusión del follaje: 18.75 y 37.5% en la materia seca (MS) de la ración. El experimento se dividió en ocho períodos de 14 días cada uno (7 para adaptación y 7 para medición de consumo y colección total de heces fecales). Los ocho tratamientos (raciones) incluyeron 25% de HSM en todo caso y 56.25% de PAA en combinación con 18.75% de follaje de Am, At, Ag y Ll en T1, T3, T5 y T7; ó 37.5% de PAA en combinación con 37% de las cuatro respectivas leguminosas en T2, T4, T6 y T8. Las raciones con Am (T1 + T2) y Ag (T5 y T6) presentaron una tendencia a mayor consumo de MS que T3 + T4, y T7 + T8 (1050 y 980 vs. 836 y 882 g/día, respectivamente, P<0.1011). El mismo patrón fue evidente en digestibilidad de MS (82 y 83 vs. 77 y 80% P<0.008), materia orgánica, fibra insoluble en detergente neutro (80 y 83 vs. 75 y 77%, P<0.013) fibra insoluble en detergente ácido y hemicelulosa (HC). Las raciones con menor nivel de leguminosa en conjunto tendieron a dar mayor consumo de MS (987 vs. 889 g/día) y superaron (P<0.05) a las de mayor nivel de leguminosa en digestibilidad de todas las fracciones químicas citadas menos HC