Early culture of the American Atlantic sturgeon Acipenser oxyrinchus oxyrinchus Mitchill, 1815 and preliminary stocking trials

We performed rearing studies with first-feeding fry and fingerling American Atlantic sturgeons Acipenser oxyrinchus oxyrinchus Mitchill, 1815 of Hudson River parentage. Sturgeons were reared at initial densities of 3.7-22.2 fish/l and offered live Artemia sp., frozen Artemia sp., or a formulated diet (Biokyowa). After 26 days, mean specific growth rate was inversely proportional to fish density and ranged from 4.9-11.1% per day. Fish fed frozen artemia were smaller but had the same survival rate as those fed live artemia. Sturgeons converted to a formulated diet with 25 % mortality at mean length and weight (sd) of 34.5 mm (3.0) and 182 mg (50). Treatments of fingerlings established at initial densities of 0.37-2.22 g/l and fed a formulated diet (Zeigler) for 28 days exhibited mean percent survival (sd) of 87.0 (0.0) to 93.3 (2.3) and had feed conversion factors of 0.50 or less. Our study showed that first-feeding American Atlantic sturgeons require low initial rearing densities (7.4 fish/l or less) and 20-26 days of continuous live artemia to facilitate conversion to formulated feed. Fish reared similarly were released into the Hudson River in 1994 and into the Nanticoke River (a Chesapeake Bay tributary) in 1996 to evaluate survival and estimate wild recruitment. Sampling in the Hudson River from 1995 through 1997 showed that hatchery fish comprised 35-53% of the total juvenile catch. Evaluation of fish released in the Nanticoke River from 1996 through 1998 showed that hatchery fish spread throughout Chesapeake Bay, made up 62 % of the total American Atlantic sturgeon catch, and had similar length-weight relationships as wild fish.Hemos realizado estudios de cultivo con juveniles en estadios iniciales y más avanzados de esturión atlántico americano Acipenser oxyrinchus oxyrinchus Mitchill, 1815 de linaje procedente del río Hudson. Los esturiones fueron cultivados a densidades iniciales de 3,7-22,2 peces por litro y alimentados con Artemia sp. viva, Artemia sp. congelada, o con una dieta formulada (Biokyowa). Después de 26 días, la tasa específica de crecimiento media fue inversamente proporcional a la densidad de peces y varió entre 4,9-11,1% por día. Los peces alimentados con artemia congelada fueron más pequeños, pero tuvieron la misma tasa de supervivencia que los alimentados con artemia viva. Los esturiones transformaron una dieta formulada con menos de 25 % de mortalidad a una longitud y peso medios de 34,5 mm (desviación típica = 3,0) y 182 mg (50). Los tratamientos de estadios más avanzados, establecidos a densidades iniciales de 0,37-2,22 g/litro y alimentados con dieta formulada (Zeigler) durante 28 días, exhibieron un porcentaje de supervivencia medio entre 87,0 (d.t. = 0,0) y 93,3 (2,3) y fueron alimentados con factores de conversión de 0,50 o menores. Nuestro estudio mostró que los juveniles en estadios iniciales de esturión atlántico americano requieren densidades de cultivo iniciales bajas (7,4 peces/litro o menores) y 20-26 días seguidos de artemia viva para facilitar la conversión a dieta formulada. Peces cultivados de este modo fueron soltados en el río Hudson en 1994 y en el río Nanticoke (un afluente de la bahía Chesapeake) en 1996 para evaluar su supervivencia y estimar el reclutamiento silvestre. El muestreo en el río Hudson desde 1995 a 1997 mostró que los peces cultivados supusieron el 35-53% de las capturas totales de juveniles. La evaluación de los peces soltados en el río Nanticoke desde 1996 a 1998 mostró que los peces cultivados se distribuyeron hacia la bahía Chesapeake, suponiendo el 62 % de las capturas totales de esturión atlántico americano, y tuvieron similares relaciones longitud-peso que los peces silvestres.Instituto Español de Oceanografí

Vector magnetometer design study: Analysis of a triaxial fluxgate sensor design demonstrates that all MAGSAT Vector Magnetometer specifications can be met

The design of the vector magnetometer selected for analysis is capable of exceeding the required accuracy of 5 gamma per vector field component. The principal elements that assure this performance level are very low power dissipation triaxial feedback coils surrounding ring core flux-gates and temperature control of the critical components of two-loop feedback electronics. An analysis of the calibration problem points to the need for improved test facilities

Measuring Vection in a Large Screen Virtual Environment

This paper describes the use of a large screen virtual environment to induce the perception of translational and rotational self-motion. We explore two aspects of this problem. Our first study investigates how the level of visual immersion (seeing a reference frame) affects subjective measures of vection. For visual patterns consistent with translation, self-reported subjective measures of self-motion were increased when the floor and ceiling were visible outside of the projection area. When the visual patterns indicated rotation, the strength of the subjective experience of circular vection was unaffected by whether or not the floor and ceiling were visible. We also found that circular vection induced by the large screen display was reported subjectively more compelling than translational vection. The second study we present describes a novel way in which to measure the effects of displays intended to produce a sense of vection. It is known that people unintentionally drift forward if asked to run in place while blindfolded and that adaptations involving perceived linear self-motion can change the rate of drift. We showed for the first time that there is a lateral drift following perceived rotational self-motion and we added to the empirical data associated with the drift effect for translational self-motion by exploring the condition in which the only self-motion cues are visual

Respondents' ratings of expressions from response scales: a two-country, two-language investigation on equivalence and translation

"The paper presents German-American research on expressions from response scales used in cross-national and cross-lingual survey research. Respondents in the United States and Germany were asked to rate expression for the degrees of intensity they were held to express. The scales used were scales of agreement, importance and for/against. The findings of the study raise as many questions as they answer. Translation-based pairings of expressions across English and German work well but not perfectly. Symmetrical response scales often lead to artificial-sounding 'scalespeak' constructions: their effect on scale responses is unknown. Well-matched translation pairings were sometimes differently scored across the populations. Germans and Americans differed in the range of scale points they employed and in the range of vocabulary used to 'explain' expressions. The study is seen as a first step towards understanding cross-national response scale issues." (author's abstract

An FTIR spectrometer for remote measurements of atmospheric composition

The JPL IV interferometer, and infrared Michelson interferometer, was built specifically for recording high resolution solar absorption spectra from remote ground-based sites, aircraft and from stratospheric balloons. The instrument is double-passed, with one fixed and one moving corner reflector, allowing up to 200-cm of optical path difference (corresponding to an unapodised spectral resolution of 0.003/cm). The carriage which holds the moving reflector is driven by a flexible nut riding on a lead screw. This arrangement, together with the double-passed optical scheme, makes the instrument resistant to the effects of mechanical distortion and shock. The spectral range of the instrument is covered by two liquid nitrogen-cooled detectors: an InSb photodiode is used for the shorter wavelengths (1.85 to 5.5 microns, 1,800 to 5,500/cm) and a HgCdTe photoconductor for the range (5.5 to 15 microns, 650 to 1,800/cm). For a single spectrum of 0.01/cm resolution, which requires a scan time of 105 seconds, the signal/noise ratio is typically 800:1 over the entire wavelength range

Microsomal triglyceride transfer protein expression in adipocytes: A new component in fat metabolism

AbstractMicrosomal triglyceride transfer protein (MTP) is a carrier of triglyceride essential for the assembly of apolipoprotein (apo)B-containing lipoproteins by the liver and the small intestine. Its role in triglyceride transfer in tissues that do not secrete lipoproteins has not been explored. In particular, MTP would seem to be a candidate for a role in triglyceride metabolism within the adipocyte. To test this hypothesis, we probed adipocytes for the presence of MTP. Immunohistochemical and biochemical studies demonstrate MTP in adipocytes from brown and white fat depots of mice and human, as well as in 3T3-L1 cells. Confocal microscopy revealed MTP throughout 3T3 cells; however, MTP fluorescence was prominent in juxtanuclear areas. In differentiated 3T3 cells MTP fluorescence was very striking around lipid droplets. In vitro lipid transfer assays demonstrated the presence of triglyceride transfer activity within microsomal fractions isolated from rat adipose tissue. In addition, quantitative rtPCR studies showed that MTP expression in mouse white fat depots was approximately 1% of MTP expression in mouse liver. MTP mRNA in differentiated 3T3 cells was approximately 13% of liver expression. Our results provide unequivocal evidence for the presence of MTP in adipocytes and present new possibilities for defining the mechanisms by which triglyceride is stored and/or hydrolyzed and mobilized

Novel Compound Heterozygous Mutations Expand the Recognized Phenotypes of \u3cem\u3eFARS2\u3c/em\u3e-linked Disease

Mutations in mitochondrial aminoacyl-tRNA synthetases are an increasingly recognized cause of human diseases, often arising in individuals with compound heterozygous mutations and presenting with system-specific phenotypes, frequently neurologic. FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase (mtPheRS), perturbations of which have been reported in 6 cases of an infantile, lethal disease with refractory epilepsy and progressive myoclonus. Here the authors report the case of juvenile onset refractory epilepsy and progressive myoclonus with compound heterozygous FARS2 mutations. The authors describe the clinical course over 6 years of care at their institution and diagnostic studies including electroencephalogram (EEG), brain magnetic resonance imaging (MRI), serum and cerebrospinal fluid analyses, skeletal muscle biopsy histology, and autopsy gross and histologic findings, which include features shared with Alpers-Huttenlocher syndrome, Leigh syndrome, and a previously published case of FARS2 mutation associated infantile onset disease. The authors also present structure-guided analysis of the relevant mutations based on published mitochondrial phenylalanyl transfer RNA synthetase and related protein crystal structures as well as biochemical analysis of the corresponding recombinant mutant proteins

SCB thermite igniter studies

The authors report on recent studies comparing the ignition threshold of temperature cycled, SCB thermite devices with units that were not submitted to temperature cycling. Aluminum/copper-oxide thermite was pressed into units at two densities, 45% of theoretical maximum density (TMD) or 47% of TMD. Half of each of the density sets underwent three thermal cycles; each cycle consisted of 2 hours at 74 C and 2 hours at {minus}54 C, with a 5 minute maximum transfer time between temperatures. The temperature cycled units were brought to ambient temperature before the threshold testing. Both the density and the thermal cycling affected the all-fire voltage. Using a 5.34 {micro}F CDU (capacitor discharge unit) firing set, the all-fire voltage for the units that were not temperature cycled increased with density from 32.99 V (45% TMD) to 39.32 V (47% TMD). The all-fire voltages for the thermally cycled units were 34.42 V (45% TMD) and 58.1 V (47% TMD). They also report on no-fire levels at ambient temperature for two component designs; the 5 minute no-fire levels were greater than 1.2 A. Units were also subjected to tests in which 1 W of RF power was injected into the bridges at 10 MHz for 5 minutes. The units survived and fired normally afterwards. Finally, units were subjected to pin-to-pin electrostatic discharge (ESD) tests. None of the units fired upon application of the ESD pulse, and all of the tested units fired normally afterwards

Semiconductor bridge, SCB, ignition studies of Al/CuO thermite

The authors briefly summarize semiconductor bridge operation and review their ignition studies of Al/CuO thermite as a function of the capacitor discharge unit (CDU) firing set capacitance, charge holder material and morphology of the CuO. Ignition thresholds were obtained using a brass charge holder and a non-conducting fiber-glass-epoxy composite material, G10. At - 18 C and a charge voltage of 50V, the capacitance thresholds were 30.1 {mu}F and 2.0 {mu}F respectively. They also present new data on electrostatic discharge (ESD) and radio frequency (RF) vulnerability tests