25 research outputs found
The American Astronomical Society, find out more The Institute of Physics, find out more The Sixth Data Release of the Radial Velocity Experiment (Rave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances
We present part 2 of the 6th and final Data Release (DR6 or FDR) of the Radial Velocity Experiment (RAVE), a magnitude-limited (9<I<12) spectroscopic survey of Galactic stars randomly selected in the southern hemisphere. The RAVE medium-resolution spectra (R~7500) cover the Ca-triplet region (8410-8795A) and span the complete time frame from the start of RAVE observations on 12 April 2003 to their completion on 4 April 2013. In the second of two publications, we present the data products derived from 518387 observations of 451783 unique stars using a suite of advanced reduction pipelines focussing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters (Teff, log(g), and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. In addition, we provide abundances of the elements Fe, Al, and Ni, as well as an overall [alpha/Fe] ratio obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios. The RAVE DR6 catalogs are cross matched with relevant astrometric and photometric catalogs, and are complemented by orbital parameters and effective temperatures based on the infrared flux method. The data can be accessed via the RAVE Web site (http://rave-survey.org) or the Vizier database
The contribution of X-linked coding variation to severe developmental disorders
Over 130 X-linked genes have been robustly associated with developmental disorders, and X-linked causes have been hypothesised to underlie the higher developmental disorder rates in males. Here, we evaluate the burden of X-linked coding variation in 11,044 developmental disorder patients, and find a similar rate of X-linked causes in males and females (6.0% and 6.9%, respectively), indicating that such variants do not account for the 1.4-fold male bias. We develop an improved strategy to detect X-linked developmental disorders and identify 23 significant genes, all of which were previously known, consistent with our inference that the vast majority of the X-linked burden is in known developmental disorder-associated genes. Importantly, we estimate that, in male probands, only 13% of inherited rare missense variants in known developmental disorder-associated genes are likely to be pathogenic. Our results demonstrate that statistical analysis of large datasets can refine our understanding of modes of inheritance for individual X-linked disorders
Galactic kinematics and dynamics from RAVE stars
We analyse the kinematics of ~400000 RAVE stars. We split the sample into hot and cold dwarfs, red-clump and non-clump giants. The kinematics of the clump giants are consistent with being identical with those of non-clump giants. We fit Gaussian velocity ellipsoids to the meridional-plane components of velocity of each star class and give formulae from which the shape and orientation of the velocity ellipsoid can be determined at any location. The data are consistent with the giants and the cool dwarfs sharing the same velocity ellipsoids; sigma_z rises from 21 kms in the plane to sim 55 kms at |z|=2 kpc, while sigma_r rises from 37 kms to 82 kms. At (R,z) the longest axis of one of these velocity ellipsoids is inclined to the Galactic plane by an angle ~0.8 arctan(z/R). We use a novel formula to obtain precise fits to the highly non-Gaussian distributions of v_phi components. We compare the observed velocity distributions with the predictions of a dynamical model fitted to the velocities of stars that lie within ~150 pc of the Sun and star counts towards the Galactic pole. The model accurately reproduces the non-Gaussian nature of the v_r and v_z distributions and provides excellent fits to the data for v_z at all locations. The model v_phi distributions for the cool dwarfs fit the data extremely well, while those for the hot dwarfs have displacements to low v_phi that grow with |z| from very small values near the plane. At |z|>0.5 kpc, the theoretical v_phi distributions for giants show a deficit of stars with large v_phi and the model v_r distributions are too narrow. Systematically over-estimating distances by 20 per cent introduces asymmetry into the model v_r and v_z distributions near the plane and but significantly improves the fits to the data at |z|>0.5 kpc. The quality of the fits lends credence to the assumed, disc-dominated, gravitational potential
Impact of Low Social Preference on the Development of Depressive and Aggressive Symptoms: Buffering by Children’s Prosocial Behavior
Holding a low social position among peers has been widely demonstrated to be associated with the development of depressive and aggressive symptoms in children. However, little is known about potential protective factors in this association. The present study examined whether increases in children’s prosocial behavior can buffer the association between their low social preference among peers and the development of depressive and aggressive symptoms in the first few school years. We followed 324 children over 1.5 years with three assessments across kindergarten and first grade elementary school. Children rated the (dis)likability of each of their classroom peers and teachers rated each child’s prosocial behavior, depressive and aggressive symptoms. Results showed that low social preference at the start of kindergarten predicted persistent low social preference at the start of first grade in elementary school, which in turn predicted increases in both depressive and aggressive symptoms at the end of first grade. However, the indirect pathways were moderated by change in prosocial behavior. Specifically, for children whose prosocial behavior increased during kindergarten, low social preference in first grade elementary school no longer predicted increases in depressive and aggressive symptoms. In contrast, for children whose prosocial behavior did not increase, their low social preference in first grade elementary school continued to predict increases in both depressive and aggressive symptoms. These results suggest that improving prosocial behavior in children with low social preference as early as kindergarten may reduce subsequent risk of developing depressive and aggressive symptom
Secondary production of caddisflies reflects environmental heterogeneity among tropical Andean streams
La historia de vida de los macroinvertebrados y la producción secundaria rara vez se han medido en las corrientes de las tierras altas tropicales a pesar de que estas corrientes son muy heterogéneas y muestran entornos ecológicos únicos en comparación con las de las tierras bajas tropicales o en la zona templada. Evaluamos la producción secundaria y los atributos de la historia de vida de la caddisfly de Grazer de perifiton (Helicopsyche spp.) Utilizando el método de frecuencia de tamaño en tres corrientes ecuatorianas de las tierras altasalcanza (2990–3727 metros sobre el nivel del mar) con características vegetativas ribereñas contrastantes y diferentes regímenes de flujo y temperatura y biomasa de perifiton (como clorofila-a). Helicopsyche mostró fuertes diferencias entre las corrientes en los atributos de la historia de vida y la producción secundaria . Estimamos que el alcance menos productivo (89 mg m −2 año −1 ) es un orden de magnitud menor que el de los dos alcances más productivos (1556–2164 mg m −2 año −1 ). La producción secundaria se correlacionó positivamente con la biomasa media anual de perifiton y se correlacionó negativamente con la temperatura media anual del agua. En comparación con estudios anteriores, la mediaLa producción secundaria de Helicopsyche fue relativamente alta. Concluimos que la producción secundaria de Helicopsyche en los arroyos de las tierras altas tropicales es muy heterogénea entre los tipos de arroyos . Esta fuerte variación entre las corrientes podría depender en última instancia de los factores ambientales que influyen en la disponibilidad de alimentos (biomasa de perifiton) y las tasas de desarrollo larvario (régimen de temperatura).Macroinvertebrate life history and secondary production have rarely been measured in tropical highland streams even though these streams are highly heterogeneous and display unique ecological settings compared to both those in the tropical
lowlands or in the temperate zone. We evaluated
secondary production and life history attributes of the
periphyton grazer caddisfly (Helicopsyche spp.) using
the size-frequency method in three Ecuadorian highland
stream reaches (2990–3727 meters above sea level) with contrasting riparian vegetative characteristics and differing flow and temperature regimes and periphyton biomass (as chlorophyll-a). Helicopsychedisplayed strong differences among streams in life history attributes and secondary production. We
estimated the least productive reach (89 mg m-2 -
year-1) to be an order of magnitude less than that of the
two more productive reaches (1556–2164 mg m-2 -
year-1). Secondary production positively correlated
with annual mean periphyton biomass and negatively
correlated with annual mean water temperature. Compared
to previous studies, mean secondary production
of Helicopsyche was relatively high. We conclude that
Helicopsyche secondary production in tropical highland
streams is highly heterogeneous among stream types. This strong variation among streams might ultimately depend on environmental factors influencing food availability (biomass of periphyton) and larval development rates (temperature regime)