8,981 research outputs found

    Cigarette smoking history is associated with poorer recovery in multiple neurocognitive domains following treatment for an alcohol use disorder.

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    Cigarette smoking is associated with neurocognitive dysfunction in various populations, including those seeking treatment for an alcohol use disorder (AUD). This study compared the rate and extent of recovery on measures of processing speed, executive functions, general intelligence, visuospatial skills and working memory in treatment-seeking alcohol dependent individuals (ALC) who were never-smokers (nvsALC), former-smoker (fsALC), and active smokers (asALC), over approximately 8 months of abstinence from alcohol. Methods: ALC participants were evaluated at approximately 1 month of abstinence (AP1; n = 132) and reassessed after 8 months of sobriety (AP2; n = 54). Never-smoking controls (CON; n = 33) completed a baseline and follow-up (n = 19) assessment approximately 9 months later. Domains evaluated were executive functions, general intelligence, processing speed, visuospatial skills and working memory; a domain composite was formed from the arithmetic average of the foregoing domains. nvsALC showed greater improvement than fsALC, asALC and CON on most domains over the AP1-AP2 interval. fsALC demonstrated greater recovery than asALC on all domains except visuospatial skills; fsALC also showed greater improvements than CON on general intelligence, working memory and domain composite. asALC did not show significant improvement on any domain over the AP1-AP2 interval. At 8 months of abstinence, asALC were inferior to CON and nvsALC on multiple domains, fsALC performed worse than nvsALC on several domains, but nvsALC were not different from CON on any domain. Our results provide robust evidence that smoking status influenced the rate and extent of neurocognitive recovery between 1 and 8 months of abstinence in this ALC cohort. Chronic smoking in AUD likely contributes to the considerable heterogeneity observed in neurocognitive recovery during extended abstinence. The findings provide additional strong support for the benefits of smoking cessation and the increasing clinical movement to offer smoking cessation resources concurrent with treatment for AUD

    Changes of frontal cortical subregion volumes in alcohol dependent individuals during early abstinence: associations with treatment outcome.

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    We previously reported that at 1-and-4 weeks of sobriety, those who relapsed after treatment demonstrated significantly smaller total frontal cortical volume than individuals who maintained abstinence for at least 12 months post treatment. The segmentation method employed did not permit examination of frontal subregions that serve as nodes of the executive, salience and emotional regulation networks; structural abnormalities in these circuits are associated with relapse in those seeking treatment for alcohol use disorders (AUD). The primary goal of this study was to determine if frontal cortical subregion volume recovery during early abstinence is associated with long-term abstinence from alcohol. We compared bilateral components of the dorsal prefrontal cortex, orbitofrontal cortex, anterior cingulate cortex and insula volumes, at 1 and 4 weeks of abstinence, between individuals who resumed drinking within 12 months of treatment (Relapsers) those who showed sustained abstinence over 12 months following treatment (Abstainers) and healthy Controls. At 1 and 4 weeks of sobriety, Relapsers demonstrated significantly smaller volumes than Controls in 15 of 20 regions of interest, while Abstainers only had smaller volumes than Controls in 5 of 20 regions. In Relapsers, increasing volumes over 1 month in multiple frontal subregions and the insula were associated with longer duration of abstinence after treatment. The persistent bilateral frontal and insula volume deficits in Relapsers over 4 weeks from last alcohol use may have implications for neurostimulation methods targeting anterior frontal/insula regions, and represent an endophenotype that differentiates those who respond more favorably to available psychosocial and pharmacological interventions

    A Class of N=1 Dual String Pairs and its Modular Superpotential

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    We compare the N=1 F-theory compactification of Donagi, Grassi and Witten with modular superpotential - and some closely related models - to dual heterotic models. We read of the F-theory spectrum from the cohomology of the fourfold and discuss on the heterotic side the gauge bundle moduli sector (including the spectral surface) and the necessary fivebranes. Then we consider the N=1 superpotential and show how a heterotic superpotential matching the F-theory computation is built up by worldsheet instantons. Finally we discuss how the original modular superpotential should be corrected by an additional modular correction factor, which on the F-theory side matches nicely with a `curve counting function' for the del Pezzo surface. On the heterotic side we derive the same factor demanding correct T-duality transformation properties of the superpotential.Comment: 18 pages, Late

    25 Gbit/s differential phase-shift-keying signal generation using directly modulated quantum-dot semiconductor optical amplifiers

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    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 213501 (2015) and may be found at https://doi.org/10.1063/1.4921785.Error-free generation of 25-Gbit/s differential phase-shift keying (DPSK) signals via direct modulation of InAs quantum-dot (QD) based semiconductor optical amplifiers (SOAs) is experimentally demonstrated with an input power level of −5 dBm. The QD SOAs emit in the 1.3-μm wavelength range and provide a small-signal fiber-to-fiber gain of 8 dB. Furthermore, error-free DPSK modulation is achieved for constant optical input power levels from 3 dBm down to only −11 dBm for a bit rate of 20 Gbit/s. Direct phase modulation of QD SOAs via current changes is thus demonstrated to be much faster than direct gain modulation

    Bullying Roles in Changing Contexts: The Stability of Victim and Bully Roles from Primary to Secondary School

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    The present study was conducted to predict bullying roles over a six years time period and across contexts differing in the degree of peer hierarchies. Out of two representative data sets from primary (N = 1525) and secondary school (N = 2958), 282 children (156 boys; 126 girls) were followed up longitudinally. Self reports on bullying experiences and peer reports about social status were assessed by a structured individual interview (in primary school) and by questionnaire given classwise (in secondary school). Risk analyses showed, that only a bully role in primary school yields a risk to be sustained in secondary school. However, victims in primary school classes with a more pronounced degree of hierarchical structuring proved stable in their role while the victim role was unstable from primary school classes with low hierarchical structuring. This interaction did not apply to bully role stability. Differential characteristics of the victim and the bully role in primary school and secondary school settings are discussed.Die vorliegende Untersuchung wurde durchgeführt, um Bullyingrollen über einen Zeitraum von sechs Jahren und Kontexte, die sich im Ausmaß der sozialen Strukturierung unterschieden, vorherzusagen. Auf der Grundlage von zwei repräsentativen Datensätzen aus der Grundschule (n= 1525) und der weiterführenden Schule (N= 2958) wurden dazu die Daten von 282 Kinder (156 Jungen, 126 Mädchen) längsschnittlich analysiert. Die Selbstberichte über Bullyingerfahrungen und Mitschülerberichte über den sozialen Status der Kinder wurden in der Grundschule durch ein strukturiertes Interview und in der weiterführenden Schule durch klassenweise Fragebogenerhebung erfasst. Riskikoanalysen zeigen, dass nur die Täterrolle in der Grundschule einen Risikofaktor für eine Täterrolle in der weiterführenden Schule darstellt. Eine Opferrolle war hingegen nur dann stabil, wenn die Opfer in Grundschulklassen mit schon ausgeprägten Dominanzstrukturen viktimisiert wurden, während aus Grundschulklassen mit geringer hierarchischer Strukturierung keine stabile Opferrolle vorhersagbar war. Dieses Interaktionmuster gilt nicht für die Stabilität der Täterrollen. Differentielle Charakteristika der Opferrolle und der Täterrolle in der Grundschule und der weiterführenden Schule werden diskutiert

    Femtosecond spectroscopy of the first events of the photochemical cycle in bacteriorhodopsin

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    The first steps in the photochemistry of bacteriorhodopsin (BR) are investigated with light pulses of 160 fs duration. Four samples are studied: (i) the purple membrane, (ii) deuterated purple membrane, (iii) BR trimers and (iv) BR monomers. In all samples the first intermediate J is formed within 430±50 fs. No isotope effect is observed in the formation of J upon deuteration, in contrast to previous reports with much higher excitation energies. Thus proton movement to or from the retinal Schiff's base is not relevant during the first step. Comparing the data for trimeric and monomeric BR suggests an upper limit of 50 fs for the transfer of excitation energy from the excitonically coupled trimer to a single retinal chromophore
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