178 research outputs found

    Non-Adiabatic Electronic and Vibrational Ring-Opening Dynamics resolved with Attosecond Core-Level Spectroscopy

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    Non-adiabatic dynamics and conical intersections play a central role in the chemistry of most polyatomic molecules, ranging from isomerization to heterocyclic ring opening and avoided photo-damage of DNA. Studying the underpinning correlated dynamics of electronic and nuclear wave packets is a major challenge in real-time and, many times involves optically dark transient states. We show that attosecond core-level spectroscopy reveals the pathway dynamics of neutral furan across its conical intersections and dark states. Our method measures electronic-nuclear correlations to detect the dephasing of electronic coherence due to nuclear motion and identifies the ring-opened isomer as the dominant product. These results demonstrate the efficacy of attosecond core level spectroscopy as a potent method to investigate the real-time dynamics of photochemical reaction pathways in complex molecular systems

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    A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei

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    GM Cep in the young (~4 Myr) open cluster Trumpler 37 has been known to be an abrupt variable and to have a circumstellar disk with very active accretion. Our monitoring observations in 2009-2011 revealed the star to show sporadic flare events, each with brightening of < 0.5 mag lasting for days. These brightening events, associated with a color change toward the blue, should originate from an increased accretion activity. Moreover, the star also underwent a brightness drop of ~1 mag lasting for about a month, during which the star became bluer when fainter. Such brightness drops seem to have a recurrence time scale of a year, as evidenced in our data and the photometric behavior of GM Cep over a century. Between consecutive drops, the star brightened gradually by about 1 mag and became blue at peak luminosity. We propose that the drop is caused by obscuration of the central star by an orbiting dust concentration. The UX Orionis type of activity in GM Cep therefore exemplifies the disk inhomogeneity process in transition between grain coagulation and planetesimal formation in a young circumstellar disk.Comment: In submission to the Astrophysical Journal, 4 figure

    Evidenzbasierte Psychotherapie der Panikstörung mit und ohne Agoraphobie : ein Überblick zur S1-Leitlinie der Deutschen Gesellschaft für Psychologie

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    Alpers GW, Gerlach AL, Heinrichs N. Evidence-based psychotherapy of panic disorder with or without agoraphobia. Psychotherapeut. 2011;56(6):535-548.From the evidence reported in the recent guidelines [Heinrichs et al. (2009) Evidenzbasierte Leitlinie zur Psychotherapie der Panikstorung mit und ohne Agoraphobie. Hogrefe, Gottingen] the following conclusions can be drawn with respect to the treatment of panic disorder with or without agoraphobia, as well as for agoraphobia without panic disorder: Every psychotherapy should be preceded by suitable diagnostics and a case formulation. The effectiveness of every psychotherapy should be evaluated with well established measures. For the treatment of panic disorder without agoraphobia, cognitive behavioral treatment (CBT) and applied relaxation have been shown to be effective (evidence grade 1). For panic disorder with agoraphobia, CBT, combination treatment (CBT plus medication), as well as panic-focused psychodynamic psychotherapy in the outpatient setting have shown short-term effectiveness (evidence grade 1). Longer lasting effects have been documented for CBT (evidence grade 1). For agoraphobia without panic disorder, CBT with a focus on situational exposure can be recommended (evidence grade 1)

    The steeply subducting edge of the Cocos Ridge : evidence from receiver functions beneath the northern Talamanca Range, south-central Costa Rica

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    The deep structure of the south-central Costa Rican subduction zone has not been studied in great detail so far because large parts of the area are virtually inaccessible. We present a receiver function study along a transect of broadband seismometers through the northern flank of the Cordillera de Talamanca (south Costa Rica). Below Moho depths, the receiver functions image a dipping positive conversion signal. This is interpreted as the subducting Cocos Plate slab, compatible with the conversions in the individual receiver functions. In finite difference modeling, a dipping signal such as the one imaged can only be reproduced by a steeply (80°) dipping structure present at least until a depth of about 70–100 km; below this depth, the length of the slab cannot be determined because of possible scattering effects. The proposed position of the slab agrees with previous results from local seismicity, local earthquake tomography, and active seismic studies, while extending the slab location to greater depths and steeper dip angle. Along the trench, no marked change is observed in the receiver functions, suggesting that the steeply dipping slab continues until the northern flank of the Cordillera de Talamanca, in the transition region between the incoming seamount segment and Cocos Ridge. Considering the time predicted for the establishment of shallow angle underthrusting after the onset of ridge collision, the southern Costa Rican subduction zone may at present be undergoing a reconfiguration of subduction style, where the transition to shallow underthrusting may be underway but still incomplete
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