Theory of Dispersed Fixed-Delay Interferometry for Radial Velocity Exoplanet Searches

The dispersed fixed-delay interferometer (DFDI) represents a new instrument concept for high-precision radial velocity (RV) surveys for extrasolar planets. A combination of Michelson interferometer and medium-resolution spectrograph, it has the potential for performing multi-object surveys, where most previous RV techniques have been limited to observing only one target at a time. Because of the large sample of extrasolar planets needed to better understand planetary formation, evolution, and prevalence, this new technique represents a logical next step in instrumentation for RV extrasolar planet searches, and has been proven with the single-object Exoplanet Tracker (ET) at Kitt Peak National Observatory, and the multi-object W. M. Keck/MARVELS Exoplanet Tracker at Apache Point Observatory. The development of the ET instruments has necessitated fleshing out a detailed understanding of the physical principles of the DFDI technique. Here we summarize the fundamental theoretical material needed to understand the technique and provide an overview of the physics underlying the instrument's working. We also derive some useful analytical formulae that can be used to estimate the level of various sources of error generic to the technique, such as photon shot noise when using a fiducial reference spectrum, contamination by secondary spectra (e.g., crowded sources, spectroscopic binaries, or moonlight contamination), residual interferometer comb, and reference cross-talk error. Following this, we show that the use of a traditional gas absorption fiducial reference with a DFDI can incur significant systematic errors that must be taken into account at the precision levels required to detect extrasolar planets.Comment: 58 pages, 11 figures, 1 table, 3 appendices. Accepted for publication in ApJS. Minor typographical corrections; update to acknowledgment

Variational formulas of higher order mean curvatures

In this paper, we establish the first variational formula and its Euler-Lagrange equation for the total $2p$-th mean curvature functional $\mathcal {M}_{2p}$ of a submanifold $M^n$ in a general Riemannian manifold $N^{n+m}$ for $p=0,1,...,[\frac{n}{2}]$. As an example, we prove that closed complex submanifolds in complex projective spaces are critical points of the functional $\mathcal {M}_{2p}$, called relatively $2p$-minimal submanifolds, for all $p$. At last, we discuss the relations between relatively $2p$-minimal submanifolds and austere submanifolds in real space forms, as well as a special variational problem.Comment: 13 pages, to appear in SCIENCE CHINA Mathematics 201

An assessment of hepatitis E virus (HEV) in US blood donors and recipients: No detectable HEV RNA in 1939 donors tested and no evidence for HEV transmission to 362 prospectively followed recipients.

BACKGROUND: Hepatitis E virus (HEV) infection has become relevant to blood transfusion practice because isolated cases of blood transmission have been reported and because HEV has been found to cause chronic infection and severe liver disease in immunocompromised patients. STUDY DESIGN AND METHODS: We tested for immunoglobulin (Ig)G and IgM antibodies to the HEV and for HEV RNA in 1939 unselected volunteer US blood donors. Subsequently, we tested the same variables in pre- and serial posttransfusion samples from 362 prospectively followed blood recipients to assess transfusion risk. RESULTS: IgG anti-HEV seroprevalence in the total 1939 donations was 18.8%: 916 of these donations were made in 2006 at which time the seroprevalence was 21.8% and the remaining 1023 donations were in 2012 when the seroprevalence had decreased to 16.0% (p \u3c 0.01). A significant (p \u3c 0.001) stepwise increase in anti-HEV seroprevalence was seen with increasing age. Eight of 1939 donations (0.4%) tested anti-HEV IgM positive; no donation was HEV RNA positive. Two recipients had an apparent anti-HEV seroconversion, but temporal relationships and linked donor testing showed that these were not transfusion-transmitted HEV infections. CONCLUSION: No transfusion-transmitted HEV infections were observed in 362 prospectively followed blood recipients despite an anti-HEV seroprevalence among donations exceeding 16%

Intrusive memories and depression following recent non-traumatic negative life events in adolescents

Background: Research in adults suggests that intrusive memories are not just found in individuals with post-traumatic stress disorder (PTSD), yet there is little evidence concerning the phenomenology of intrusive memories in children and adolescents. The present study investigated the frequency of intrusive memories following a recent negative event in an adolescent school sample, and considered the application of cognitive theory to understanding the maintenance of intrusive memories of recent negative events, and their role in maintaining depression. Methods: High school students (aged 11-18 years; n = 231) completed questionnaires concerning affect experienced during a recent negative event, the frequency of subsequent intrusive memories, memory quality, thought suppression, post-traumatic stress and depressive symptoms. Results: Most participants had experienced at least one intrusive memory in the previous week, at similar rates for traumatic events and life events. In non-trauma exposed youth, peri-event affect and memory quality accounted for unique variance in a regression model of intrusive memory frequency, while peri-event affect, memory quality, and intrusive memory frequency accounted for unique variance in a regression model of depression. Limitations: The study needs replication in younger children. Interview methods may be required to ensure that intrusive memories are being assessed and not intrusive thoughts or ruminations. Conclusions: Intrusive memories are common reaction to negative events in adolescents, and may be involved in maintaining subsequent depressed mood. The nature of event memories may have a role in the maintenance of such psychopathology, and may be a target for psychological interventions in this age group

Molecular Sites for the Positive Allosteric Modulation of Glycine Receptors by Endocannabinoids

Glycine receptors (GlyRs) are transmitter-gated anion channels of the Cys-loop superfamily which mediate synaptic inhibition at spinal and selected supraspinal sites. Although they serve pivotal functions in motor control and sensory processing, they have yet to be exploited as drug targets partly because of hitherto limited possibilities for allosteric control. Endocannabinoids (ECs) have recently been characterized as direct allosteric GlyR modulators, but the underlying molecular sites have remained unknown. Here, we show that chemically neutral ECs (e.g. anandamide, AEA) are positive modulators of α1, α2 and α3 GlyRs, whereas acidic ECs (e.g. N-arachidonoyl-glycine; NA-Gly) potentiate α1 GlyRs but inhibit α2 and α3. This subunit-specificity allowed us to identify the underlying molecular sites through analysis of chimeric and mutant receptors. We found that alanine 52 in extracellular loop 2, glycine 254 in transmembrane (TM) region 2 and intracellular lysine 385 determine the positive modulation of α1 GlyRs by NA-Gly. Successive substitution of non-conserved extracellular and TM residues in α2 converted NA-Gly-mediated inhibition into potentiation. Conversely, mutation of the conserved lysine within the intracellular loop between TM3 and TM4 attenuated NA-Gly-mediated potentiation of α1 GlyRs, without affecting inhibition of α2 and α3. Notably, this mutation reduced modulation by AEA of all three GlyRs. These results define molecular sites for allosteric control of GlyRs by ECs and reveal an unrecognized function for the TM3-4 intracellular loop in the allosteric modulation of Cys-loop ion channels. The identification of these sites may help to understand the physiological role of this modulation and facilitate the development of novel therapeutic approaches to diseases such as spasticity, startle disease and possibly chronic pain

The effect of verbalization strategy on wisconsin card sorting test performance in schizophrenic patients receiving classical or atypical antipsychotics

BACKGROUND: A number of reports showed en encouraging remediation in some patients' executive deficits thanks to the use of 'information processing strategies'. Moreover the impact of antipsychotics on cognitive functions of the schizophrenics is an important issue, especially if an integrated psychosocial treatment is needed. The aim of this paper is to evaluate different executive performance and response to verbalization, a strategy of the Wisconsin Card Sorting Test (WCST) remediation, in subjects on classical vs atypical antipsychotic (AP) treatment. METHODS: Sixty-three schizophrenic subjects undertook the WCST under standard and modified (verbalization) administration. Subjects were stratified by the kind of WCST response (i.e. good, poor and remediable) and AP treatment (i.e. atypical vs. classical). RESULTS: Subjects on atypical APs showed a better performance than those on classical ones. More poor performers who did not remediate were seen in the sample with classical Aps while subjects who remediated the performance were seen in the subgroup with atypical APs only. An increase of perseverative and total errors was seen in poor performers subjects on classical APs. CONCLUSION: Subjects on atypicals showed a better cognitive pattern in terms of WCST performance. Since the naturalistic assignment of medication we cannot draw conclusions about its effect on cognitive performance and its interaction with cognitive remediation potential. However the data lead us to hypothesize that subjects with potential room for remediation did so with the atypical APs

Complejos de Renio para Reducción de CO2 Inmovilizados en Superficies de Oro: Propiedades Fisicoquímicas, Espectroscopía SFG y Simulación Computacional

Introducción. Reducción electroquímica de CO2 impulsada por fuentes de energías renovables, como eólica y solar, es un prometedor camino para la conversión en combustibles o precursores químicos. Los complejos de renio están entre los más eficientes catalizadores homogéneos para convertir CO2 a CO con alta actividad electrocatalítica.1 Una estrategia para la reducción eletrocatalítica de CO2 es la funcionalización de electrodos, que combina la estabilidad de sistemas heterogéneos con la alta selectividad de catalizadores moleculares. En este contexto, efectos estructurales y electrónicos en el catalizador en condiciones de trabajo pueden revelar importantes parámetros para el diseño y optimización de materiales catalíticos.2Resultados y Conclusiones. Reportamos la síntesis y caracterización de nuevos complejos de renio en condiciones homogéneas y heterogéneas. [Re(CO)3(L)Cl] con L = 3,3?-ditio-bipiridina y 3,3?-tio-bipiridina fueron obtenidos y caracterizados por análisis electroquímicos, espectroscopía SFG y modelado computacional, obteniéndose detalles fundamentales de la estructura electrónica, actividad catalítica y orientación del anclaje sobre la superficie del electrodo de oro, reguladas por el diseño del ligando.Fil: Cattaneo, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Kiefer, Laura. University of Emory; Estados UnidosFil: Gebre, Sara. University of Emory; Estados UnidosFil: Ge, Aimin. University of Emory; Estados UnidosFil: Liu, Qiliang. University of Emory; Estados UnidosFil: Guo, Facheng. University of Yale; Estados UnidosFil: Kelly, Harvey R.. University of Yale; Estados UnidosFil: Videla, Pablo. University of Yale; Estados UnidosFil: Lian, Tinquan. University of Emory; Estados UnidosFil: Batista, Victor S.. University of Yale; Estados UnidosXXI Congreso Argentino de Fisicoquímica y Química InorgánicaSan Miguel de TucumánArgentinaUniversidad Nacional de Tucumán. Facultad de Bioquímica, Química y FarmaciaAsociación Argentina de Investigaciones Fisicoquímica

Completing the framework of AdS/QCD: h_1/b_1 mesons and excited omega/rho's

We extend the "hard wall" gravity dual of QCD by including tensor fields b_{MN} that correspond to the QCD quark bilinear operators qbar sigma^{mu nu} q. These fields give rise to a spectrum of states which include the h_1 and b_1 mesons, as well as a tower of excited omega/rho meson states. We also identify the lowest-dimension term which leads to mixing between the new rho states and the usual tower of rho mesons when chiral symmetry is broken.Comment: 37 pages, uses jheppub.sty; v2: Added reference and revised discussion of interaction term