88 research outputs found

    Trauma as a predictor of exposure and response prevention (Ex/RP) treatment outcomes for patients with obsessive-compulsive disorder (OCD) in a clinical setting

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    Background: Trauma has been found to be highly prevalent among individuals diagnosed with obsessive-compulsive disorder (OCD) and to impact the onset, maintenance, and severity of OCD symptoms. Little is known, however, about how trauma might affect outcomes for individuals engaging in exposure and response prevention (Ex/RP). Despite Ex/RP being the most widely implemented treatment for OCD, lack of consideration for psychosocial factors, like experienced trauma, has been cited as a possible limitation of the treatment. Furthermore, intolerance of uncertainty (IU), anxiety sensitivity (AS), and emotion regulation (ER) are transdiagnostic variables most commonly associated with the presence of posttraumatic stress and OCD treatment success, respectively, however, no research to date has identified whether such variables might be implicated in the relationship between trauma and Ex/RP treatment outcomes. Objective: The primary aim of this study is to investigate how trauma might predict Ex/RP treatment outcomes for patients with OCD. The questions this study seeks to answer are: (1) Do OCD patients with trauma experience more severe OCD symptoms, IU, AS, and ER at pretreatment, compared to those without trauma? (2) Do the variables (i.e., IU, AS, and ER) mediate the relationship between trauma and Ex/RP treatment outcomes? Methods: Analyses of archival data will be performed on pretreatment and posttreatment measures of treatment-seeking patients with a primary OCD at a specialty anxiety clinic. Based on patient self-report on the Posttraumatic Diagnostic Scale for the DSM-5 (PDS-5; Foa, 2013) OCD patients will be separated into two groups: (1) those reporting no trauma experiences (OCD group), and (2) those reporting at least one trauma experience (OCDT group). A MANOVA will be used to assess whether the OCDT group report more severe OCD symptoms, IU, AS, and ER at pretreatment, compared to the OCD group. Second, based on those findings, a mediation analysis will be used to assess whether the variable found to differ most significantly between the groups (IU, AS, & ER) mediate the relationship between trauma and Ex/RP outcomes (severity change scores) at posttreatment. Discussion: Findings from this study have the potential to inform clinical practice around the assessment of OCD symptom presentation and the need to consider the impact of trauma and related transdiagnostic variables in the implementation of Ex/RP treatment to provide greater opportunity for successful treatment outcomes

    Social media use, connectedness, and depression in graduate students

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    This study will examine the relationship between social media use, sense of connectedness, and depression among graduate students. Graduate students are often disconnected from their social supports due to their program\u27s demands; additionally, the risk of depression in this population has been established in the literature. The impact of social media on depression has been investigated, and the results are discrepant. The relationship between a sense of connection, the use of social media, and depression in a graduate student population has not yet been explored. Graduate students at The Philadelphia College of Osteopathic Medicine (PCOM) and other universities studying psychology, medicine, biomedical science, or physician assistant studies will be included. Participants will be recruited through email and social media platforms. A control group of participants that do not use social media will be included. The following measures will be used: The Social Connectedness Scale-Revised (SCS-R), The Generalized Problematic Internet Use Scale 2 (GPIUS2), and The Patient Health Questionnaire-9 (PHQ-9). An inverse relationship is predicted between connectedness and depression. Participants with high scores on problematic internet use are anticipated to have elevated levels of depression and a low sense of connection compared to participants with low scores on problematic use. The subscales from the GPIUS2 are hypothesized to be predictive of participants\u27 sense of connection

    Theoretical study of finite temperature spectroscopy in van der Waals clusters. I. Probing phase changes in CaAr_n

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    The photoabsorption spectra of calcium-doped argon clusters CaAr_n are investigated at thermal equilibrium using a variety of theoretical and numerical tools. The influence of temperature on the absorption spectra is estimated using the quantum superposition method for a variety of cluster sizes in the range 6<=n<=146. At the harmonic level of approximation, the absorption intensity is calculated through an extension of the Gaussian theory by Wadi and Pollak [J. Chem. Phys. vol 110, 11890 (1999)]. This theory is tested on simple, few-atom systems in both the classical and quantum regimes for which highly accurate Monte Carlo data can be obtained. By incorporating quantum anharmonic corrections to the partition functions and respective weights of the isomers, we show that the superposition method can correctly describe the finite-temperature spectroscopic properties of CaAr_n systems. The use of the absorption spectrum as a possible probe of isomerization or phase changes in the argon cluster is discussed at the light of finite-size effects.Comment: 17 pages, 9 figure

    Catalysis to discriminate single atoms from subnanometric ruthenium particles in ultra-high loading catalysts

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    We report a procedure for preparing ulta-high metal loading (10-20 % w/w Ru) Ru@C60 nanostructured catalysts comprising exclusively Ru single atoms. We show that by changing the Ru/C60 ratio and the nature of the solvent used during the synthesis, it is possible to increase the Ru loading up to 50% w/w, and to produce hetero-structures containing subnanometric Ru nanoparticles. Several techniques such as high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy ‚Äď high angle annular dark field (STEM-HAADF), Raman spectroscopy, wideangle X-ray scattering (WAXS), extended X-ray absorption fine structure (EXAFS) and X-ray photoelectron spectroscopy (XPS) together with theoretical calculations were used to characterize these materials. At such high metal loading, the distinction between Ru single atoms and clusters is not trivial, even with this combination of techniques. We evaluated the catalytic properties of these materials for the hydrogenation of nitrobenzene and 2,3-dimethyl-2-butene. The catalysts containing only Ru single atoms are much less active for these reactions than the ones containing clusters. For nitrobenzene hydrogenation, this is because electro-deficient Ru single atoms and few atom Run clusters are not performant for H2 activation compared to larger clusters (n ‚Č• 13), as shown by density functional theory (DFT) calculations. For the more crowded substrate 2,3-dimethyl-2-butene, DFT calculations have shown that this is due to steric hindrance. These simple tests can thus been used to distinguish samples containing metallic sub-nanometer nanoparticles. These novel catalysts are also extremely active for the hydrogenation of -substituted 2,3-dimethyl-2-butene

    Thermodynamics of Na_8 and Na_{20} clusters studied with ab-initio electronic structure methods

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    We study the thermodynamics of Na_8 and Na_{20} clusters using multiple-histogram methods and an ab initio treatment of the valence electrons within density functional theory. We consider the influence of various electron kinetic-energy functionals and pseudopotentials on the canonical ionic specific heats. The results for all models we consider show qualitative similarities, but also significant temperature shifts from model to model of peaks and other features in the specific-heat curves. The use of phenomenological pseudopotentials shifts the melting peak substantially (~ 50--100 K) when compared to ab-initio results. It is argued that the choice of a good pseudopotential and use of better electronic kinetic-energy functionals has the potential for performing large time scale and large sized thermodynamical simulations on clusters.Comment: LaTeX file and EPS figures. 24 pages, 13 figures. Submitted to Phys. Rev.

    Thermal expansion in small metal clusters and its impact on the electric polarizability

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    The thermal expansion coefficients of NaN\mathrm{Na}_{N} clusters with 8‚ȧN‚ȧ408 \le N \le 40 and Al7\mathrm{Al}_{7}, Al13‚ąí\mathrm{Al}_{13}^- and Al14‚ąí\mathrm{Al}_{14}^- are obtained from {\it ab initio} Born-Oppenheimer LDA molecular dynamics. Thermal expansion of small metal clusters is considerably larger than that in the bulk and size-dependent. We demonstrate that the average static electric dipole polarizability of Na clusters depends linearly on the mean interatomic distance and only to a minor extent on the detailed ionic configuration when the overall shape of the electron density is enforced by electronic shell effects. The polarizability is thus a sensitive indicator for thermal expansion. We show that taking this effect into account brings theoretical and experimental polarizabilities into quantitative agreement.Comment: 4 pages, 2 figures, one table. Accepted for publication in Physical Review Letters. References 10 and 23 update

    Ionic structure and photoabsorption in medium sized sodium clusters

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    We present ground-state configurations and photoabsorption spectra of Na-7+, Na-27+ and Na-41+. Both the ionic structure and the photoabsorption spectra of medium-size sodium clusters beyond Na-20 have been calculated self-consistently with a nonspherical treatment of the valence electrons in density functional theory. We use a local pseudopotential that has been adjusted to experimental bulk properties and the atomic 3s level of sodium. Our studies have shown that both the ionic structure of the ground state and the positions of the plasmon resonances depend sensitively on the pseudopotential used in the calculation, which stresses the importance of its consistent use in both steps.Comment: 4 pages, 3 figures. Accepted for publication in PRB, tentatively July 15th, 1998 some typos corrected, brought to nicer forma

    Ionic and electronic structure of sodium clusters up to N=59

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    We determined the ionic and electronic structure of sodium clusters with even electron numbers and 2 to 59 atoms in axially averaged and three-dimensional density functional calculations. A local, phenomenological pseudopotential that reproduces important bulk and atomic properties and facilitates structure calculations has been developed. Photoabsorption spectra have been calculated for Na2\mathrm{Na}_2, Na8\mathrm{Na}_8, and Na9+\mathrm{Na}_9^+ to Na59+\mathrm{Na}_{59}^+. The consistent inclusion of ionic structure considerably improves agreement with experiment. An icosahedral growth pattern is observed for Na19+\mathrm{Na}_{19}^+ to Na59+\mathrm{Na}_{59}^+. This finding is supported by photoabsorption data.Comment: To appear in Phys. Rev. B 62. Version with figures in better quality can be requested from the author

    A neural network-based method for merging ocean color and Argo data to extend surface bio-optical properties to depth: Retrieval of the particulate backscattering coefficient

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    The present study proposes a novel method that merges satellite ocean color bio-optical products with Argo temperature-salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (bbp). This neural network-based method (SOCA-BBP for Satellite Ocean-Color merged with Argo data to infer the vertical distribution of the Particulate Backscattering coefficient) uses three main input components: (1) satellite-based surface estimates of bbp and chlorophyll a concentration matched up in space and time with (2) depth-resolved physical properties derived from temperature-salinity profiles measured by Argo profiling floats and (3) the day of the year of the considered satellite-Argo matchup. The neural network is trained and validated using a database including 4725 simultaneous profiles of temperature-salinity and bio-optical properties collected by Bio-Argo floats, with concomitant satellite-derived products. The Bio-Argo profiles are representative of the global open-ocean in terms of oceanographic conditions, making the proposed method applicable to most open-ocean environments. SOCA-BBP is validated using 20% of the entire database (global error of 21%). We present additional validation results based on two other independent data sets acquired (1) by four Bio-Argo floats deployed in major oceanic basins, not represented in the database used to train the method; and (2) during an AMT (Atlantic Meridional Transect) field cruise in 2009. These validation tests based on two fully independent data sets indicate the robustness of the predicted vertical distribution of bbp. To illustrate the potential of the method, we merged monthly climatological Argo profiles with ocean color products to produce a depth-resolved climatology of bbp for the global ocean

    Two databases derived from BGC-Argo float measurements for marine biogeochemical and bio-optical applications

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    Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world’s oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradiance at three wavelengths, and photosynthetically available radiation) variables are collected in the upper 1000m every 1 to 10 days. The database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically developed procedures and its time series is quality-assessed to identify issues related to biofouling and/or instrument drift. A second database of 5748 profile-derived products within the first optical depth (i.e., the layer of interest for satellite remote sensing) is also presented and its spatiotemporal distribution discussed. This database, devoted to field and remote ocean color applications, includes diffuse attenuation coefficients for downward irradiance at three narrow wavebands and one broad waveband (photosynthetically available radiation), calibrated chlorophyll and fluorescent dissolved organic matter concentrations, and single wavelength particulate optical backscattering. To demonstrate the applicability of these databases, data within the first optical depth are compared with previously established bio-optical models and used to validate remotely derived bio-optical products. The quality-controlled databases are publicly available from the SEANOE (SEA scieNtific Open data Edition) publisher at https://doi.org/10.17882/49388 and https://doi.org/10.17882/47142 for vertical profiles and products within the first optical depth, respectively
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