Genome-wide association study identifies new locus associated with OCD [preprint]

Obsessive-compulsive disorder (OCD) is a heritable disorder, but no definitive, replicated OCD susceptibility loci have yet been identified by any genome-wide association study (GWAS). Here, we report results from a GWAS in the largest OCD case-control sample (N = 14,140 OCD cases and N = 562,117 controls) to date. We explored the genetic architecture of OCD, including its genetic relationships to other psychiatric and non-psychiatric phenotypes. In the GWAS analysis, we identified one SNP associated with OCD at a genome-wide significant level. Subsequent gene-based analyses identified additional two genes as potentially implicated in OCD pathogenesis. All SNPs combined explained 16% of the heritability of OCD. We show sub-stantial positive genetic correlations between OCD and a range of psychiatric disorders, including anxiety disorders, anorexia nervosa, and major depression. We thus for the first time provide evidence of a genome-wide locus implicated in OCD and strengthen previous literature suggesting a polygenic nature of this disorder

Methylobacillus flagellatus KT contains a novel cbo-type cytochrome oxidase

AbstractThe o-type oxidase from the methanol-grown obligate methylotroph Methylobacillus flagellatus KT has been purified to homogeneity. The complex is composed of four subunits (57, 40, 35 and 30 kDa). It contains six haems (4C:1B:1O) and one copper atom per molecule. It is proposed that the haem O-CuB binuclear centre and a low-spin haem B are located in subunit I (57 kDa), two haems C reside in the cytochrome c homodimer (35 kDa), two haems C belong to the dihaem cytochrome c (30 kDa). The presented data provide evidence that cytochrome cbo is a novel representative of the haem–copper oxidase superfamily

Infrared spectroscopy of deuterated acetylene in solid parahydrogen and the helium recovery initiative

The linear tetratomic organic molecule acetylene, HCCH, has been studied extensively throughout the past century via numerous spectroscopic experiments, exploiting wavelengths across the electromagnetic spectrum. Both the mono- and di-deutero acetylene isotopologues have also been widely studied, namely HCCD and DCCD. In this presentation, I will present the Fourier transform infrared (FTIR) spectroscopy of DCCD in solid parahydrogen (pH$_{2}$) in the low-temperature regime (1.5-5.0 K). We intend to perform UV photochemical studies on DCCD doped solid pH$_{2}$ and, therefore, the infrared spectroscopy must be characterized prior. The FTIR spectrum of DCCD isolated in solid pH$_{2}$ exhibits rich fine structure in the \nub{3} asymmetric C-D stretch region. Some of the observed peaks may arise from the formation of weakly bound acetylene dimers, or potentially even larger clusters. We can test this hypothesis by varying the DCCD concentration in separate experiments and temperature cycling the matrix to look for irreversible cluster growth. In preliminary experiments we observe trace amounts of the lighter isotopologues (HCCD and HCCH) and so these species can also cluster with DCCD, adding to the complexity of the spectra. We remark that ortho-hydrogen clustering to DCCD may also be occurring and we have ways to check that as well. In order to make better sense of the FTIR spectrum of DCCD doped pH$_{2}$, a comparison with the simulated low temperature gas-phase spectrum will also be presented. This will allow us to address issues related to the extent of the rotational motion of DCCD in solid pH$_{2}$. A liquid helium bath cryostat is used to grow and maintain the DCCD doped pH$_{2}$ crystals for spectroscopic characterization. Helium is a non-renewable resource and in recent years the Anderson group has been building a helium recovery system. This Helium Recovery Initiative (HRI) will be discussed in an effort to describe how we implemented this new experimental system in our laboratory and to point out the major challenges we faced. One of the main goals of the HRI is to promote sustainable helium use, permitting smaller cryogenics laboratories to continue conducting research with liquid helium

NUCLEAR SPIN CONVERSION OF PROPYNE IN SOLID PARAHYDROGEN

We report observations of propyne (\chem{H_3CCCH}) nuclear spin conversion (NSC) in solid parahydrogen (para-\chem{H_2}) at 1.7 K via high-resolution matrix isolation infrared spectroscopy. A rapid vapor deposition technique is used to codeposit room temperature \chem{H_3CCCH} and precooled para-\chem{H_2} gas streams onto a cold substrate maintained below 2.4 K with flow rates that ensure the expeditious growth of monomer-doped solids. This study will focus on the $\nu_{2}$ and $\nu_{6}$ modes of propyne in the methyl \chem{C–H} stretching region near 3.4 $\mu$m, which correspond to parallel and perpendicular rovibrational bands, respectively. For both bands, temporal changes in peak intensities are detected that are characteristic of NSC. In this way, NSC can be used to assign peaks originating from \textit{K}=0 (\textit{A}, \textit{I}=3/2) and \textit{K}=1 (\textit{E}, \textit{I}=1/2) levels, even when absorptions are strongly overlapping. Based on these observations, the fine structure observed in these two bands can be assigned to \textit{K}-rotational structure. At these temperatures, the \textit{K}=1 rotational state should not be populated without nuclear spin restrictions on the total wavefunction. Thus, the slow NSC process allows the \textit{K}=1 level population to be partially trapped in the low-temperature solid. The observation of this NSC process means that the \textit{K} rotational quantum number is at least partially conserved, indicating \chem{H_3CCCH} rotates about its symmetry axis in the para-\chem{H_2} matrix. The extracted time constant for NSC ($\tau$=270(10) min) is within an order of magnitude of measurements for other methyl-rotors (\chem{H_3CX}; \chem{X} = \chem{H};\footnote{Y. Miyamoto, M. Fushitani, D. Ando, T. Momose, \textit{J. Chem. Phys. }\textbf{128}, 114502 (2008).} \chem{F};\footnote{Y.-P. Lee, Y.-J. Wu, J.T. Hougen, \textit{J. Chem. Phys. }\textbf{129}, 104502 (2008).} \chem{OH};\footnote{Y.-P. Lee, Y.-J. Wu, R.M. Lees, L.-H. Xu, J.T. Hougen, \textit{Science }\textbf{311}, 365 (2006).} \chem{C(O)CH=COHCH_3}\footnote{R.R. Lozada-Garcia, J. Ceponkus, M. Chevalier, W. Chin, J.-M. Mestdagh, C. Cr\'{e}pin, \textit{Angew. Chem. Int. Ed. }\textbf{51}, 6947 (2012).}) trapped in para-\chem{H_2} matrices, however, this is the fastest rate of relaxation measured to date. These findings are discussed in light of accepted models for NSC and the various rovibrational selection-rules for the above-mentioned molecules

Inlet flowfield investigation. Part 2: Computation of the flow about a supercruise forebody at supersonic speeds

A numerical procedure which solves the parabolized Navier-Stokes (PNS) equations on a body fitted mesh was used to compute the flow about the forebody of an advanced tactical supercruise fighter configuration in an effort to explore the use of a PNS method for design of supersonic cruise forebody geometries. Forebody flow fields were computed at Mach numbers of 1.5, 2.0, and 2.5, and at angles-of-attack of 0 deg, 4 deg, and 8 deg. at each Mach number. Computed results are presented at several body stations and include contour plots of Mach number, total pressure, upwash angle, sidewash angle and cross-plane velocity. The computational analysis procedure was found reliable for evaluating forebody flow fields of advanced aircraft configurations for flight conditions where the vortex shed from the wing leading edge is not a dominant flow phenomenon. Static pressure distributions and boundary layer profiles on the forebody and wing were surveyed in a wind tunnel test, and the analytical results are compared to the data. The current status of the parabolized flow flow field code is described along with desirable improvements in the code

No Fossil Disk in the T Tauri Multiple System V773 Tau

We present new multi-epoch near-infrared and optical high-angular images of the V773 Tau pre-main sequence triple system, a weak-line T Tauri (WTTS) system in which the presence of an evolved, ``fossil'' protoplanetary disk has been inferred on the basis of a significant infrared excess. Our images reveal a fourth object bound to the system, V773 Tau D. While it is much fainter than all other components at 2 micron, it is the brightest source in the system at 4.7 micron. We also present medium-resolution K band adaptive optics spectroscopy of this object, which is featureless with the exception of a weak Br gamma emission line. Based on this spectrum and on the spectral energy distribution of the system, we show that V773 Tau D is another member of the small class of ``infrared companions'' (IRCs) to T Tauri stars. It is the least luminous, and probably the least massive, component of the system, as opposed to most other IRCs, which suggests that numerous low-luminosity IRCs such as V773 Tau D may still remain to be discovered. Furthermore, it is the source of the strong IR excess in the system. We therefore reject the interpretation of this excess as the signature of a fossil (or ``passive'') disk and further suggest that these systems may be much less frequent than previously thought. We further show that V773 Tau C is a variable classical T Tauri star (CTTS) and that its motion provides a well constrained orbital model. We show that V773 Tau D can be dynamically stable within this quadruple system if its orbit is highly inclined. Finally, V773 Tau is the first multiple system to display such a variety of evolutionary states (WTTS, CTTS, IRC), which may be the consequence of the strong star-star interactions in this compact quadruple system.Comment: Accepted for publication in Astrophysical Journal, 29 pages, 2 tables, 5 figure

Le médecin, son patient et ses pairs:Une nouvelle approche de la relation thérapeutique

Les travaux relatifs à la relation thérapeutique ont jusqu'alors négligé un élément décisif: les relations entre médecins. Le cas de la cancérologie révèle que l'attention portée à ces relations est susceptible d'apporter un nouvel éclairage à la compréhension de la relation thérapeutique. En particulier, la concurrence entre médecins sur l'activité et sur la définition du bon traitement représente une incertitude supplémentaire majeure pour chaque médecin dans sa tentative de maîtriser la relation avec son patient. Dès lors, les stratégies médicales d'organisation et de réorganisation locale de la prise en charge peuvent s'analyser comme des tentatives de réduction de cette incertitude. Réciproquement, la relation au patient n'a pas pour seule fin la guérison mais constitue aussi un autre moyen de maîtriser cette incertitude et, consécutivement, d'améliorer les relations thérapeutiques futures : le patient est pour le médecin un moyen d'obtenir de l'information sur les comportements de ses pairs et un moyen d'échange pour entretenir des relations privilégiées avec certains d'entre eux

Modes of Multiple Star Formation

This paper argues that star forming environments should be classified into finer divisions than the traditional isolated and clustered modes. Using the observed set of galactic open clusters and theoretical considerations regarding cluster formation, we estimate the fraction of star formation that takes place within clusters. We find that less than 10% of the stellar population originates from star forming regions destined to become open clusters, confirming earlier estimates. The smallest clusters included in the observational surveys (having at least N=100 members) roughly coincide with the smallest stellar systems that are expected to evolve as clusters in a dynamical sense. We show that stellar systems with too few members N < N_\star have dynamical relaxation times that are shorter than their formation times (1-2 Myr), where the critical number of stars N_\star \approx 100. Our results suggest that star formation can be characterized by (at least) three principal modes: I. isolated singles and binaries, II. groups (N<N_\star), and III. clusters (N>N_\star). Many -- if not most -- stars form through the intermediate mode in stellar groups with 10<N<100. Such groups evolve and disperse much more rapidly than open clusters; groups also have a low probability of containing massive stars and are unaffected by supernovae and intense ultraviolet radiation fields. Because of their short lifetimes and small stellar membership, groups have relatively little effect on the star formation process (on average) compared to larger open clusters.Comment: accepted to The Astrophysical Journa

Strong Nebular Line Ratios in the Spectra of z~2-3 Star-forming Galaxies: First Results from KBSS-MOSFIRE

We present initial results of a deep near-IR spectroscopic survey covering the 15 fields of the Keck Baryonic Structure Survey (KBSS) using MOSFIRE on the Keck 1 telescope, focusing on a sample of 251 galaxies with redshifts 2.0< z < 2.6, star-formation rates 2 < SFR < 200 M_sun/yr, and stellar masses 8.6 < log(M*/M_sun) < 11.4, with high-quality spectra in both H- and K-band atmospheric windows. We show unambiguously that the locus of z~2.3 galaxies in the "BPT" nebular diagnostic diagram exhibits a disjoint, yet similarly tight, relationship between the ratios [NII]6585/Halpha and [OIII]/Hbeta as compared to local galaxies. Using photoionization models, we argue that the offset of the z~2.3 locus relative to z~ 0 is explained by a combination of harder ionizing radiation field, higher ionization parameter, and higher N/O at a given O/H than applies to most local galaxies, and that the position of a galaxy along the z~2.3 star-forming BPT locus is surprisingly insensitive to gas-phase oxygen abundance. The observed nebular emission line ratios are most easily reproduced by models in which the net ionizing radiation field resembles a blackbody with effective temperature T_eff = 50000-60000 K and N/O close to the solar value at all O/H. We critically assess the applicability of commonly-used strong line indices for estimating gas-phase metallicities, and consider the implications of the small intrinsic scatter in the empirical relationship between excitation-sensitive line indices and stellar mass (i.e., the "mass-metallicity" relation), at z~2.3.Comment: 41 pages, 25 figures, accepted for publication in the Astrophysical Journal. Version with full-resolution figures available at http://www.astro.caltech.edu/~ccs/mos_bpt_submit.pd