4,806 research outputs found

    A Contextual Approach to Experiential Avoidance and Social Anxiety: Evidence From an Experimental Interaction and Daily Interactions of People With Social Anxiety Disorder

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    Experiential avoidance (EA), the tendency to avoid internal, unwanted thoughts and feelings, is hypothesized to be a risk factor for social anxiety. Existing studies of experiential avoidance rely on trait measures with minimal contextual consideration. In two studies, we examined the association between experiential avoidance and anxiety within real-world social interactions. In the first study, we examined the effect of experiential avoidance on social anxiety in everyday life. For 2 weeks, 37 participants with Social Anxiety Disorder (SAD) and 38 healthy controls provided reports of experiential avoidance and social anxiety symptoms during face-to-face social interactions. Results showed that momentary experiential avoidance was positively related to anxiety symptoms during social interactions and this effect was stronger among people with SAD. People low in EA showed greater sensitivity to the level of situational threat than high EA people. In the second study, we facilitated an initial encounter between strangers. Unlike Study 1, we experimentally created a social situation where there was either an opportunity for intimacy (self-disclosure conversation) or no such opportunity (small-talk conversation). Results showed that greater experiential avoidance during the self-disclosure conversation temporally preceded increases in social anxiety for the remainder of the interaction; no such effect was found in the small-talk conversation. Our findings provide insight into the association between experiential avoidance on social anxiety in laboratory and naturalistic settings, and demonstrate that the effect of EA depends upon level of social threat and opportunity

    Randomized sham-controlled trial of repetitive transcranial magnetic stimulation in treatment-resistant obsessive–compulsive disorder

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    In open trials, 1-Hz repetitive transcranial magnetic stimulation (rTMS) to the supplementary motor area (SMA) improved symptoms and normalized cortical hyper-excitability of patients with obsessive–compulsive disorder (OCD). Here we present the results of a randomized sham-controlled double-blind study. Medication-resistant OCD patients (n=21) were assigned 4 wk either active or sham rTMS to the SMA bilaterally. rTMS parameters consisted of 1200 pulses/d, at 1 Hz and 100% of motor threshold (MT). Eighteen patients completed the study. Response to treatment was defined as a ≽25% decrease on the Yale–Brown Obsessive Compulsive Scale (YBOCS). Non-responders to sham and responders to active or sham rTMS were offered four additional weeks of open active rTMS. After 4 wk, the response rate in the completer sample was 67% (6/9) with active and 22% (2/9) with sham rTMS. At 4 wk, patients receiving active rTMS showed on average a 25% reduction in the YBOCS compared to a 12% reduction in those receiving sham. In those who received 8-wk active rTMS, OCD symptoms improved from 28.2±5.8 to 14.5±3.6. In patients randomized to active rTMS, MT measures on the right hemisphere increased significantly over time. At the end of 4-wk rTMS the abnormal hemispheric laterality found in the group randomized to active rTMS normalized. The results of the first randomized sham-controlled trial of SMA stimulation in the treatment of resistant OCD support further investigation into the potential therapeutic applications of rTMS in this disabling condition

    Effects of Heating and Cooling on Nerve Terminal Impulses Recorded from Cold-sensitive Receptors in the Guinea-pig Cornea

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    An in vitro preparation of the guinea-pig cornea was used to study the effects of changing temperature on nerve terminal impulses recorded extracellularly from cold-sensitive receptors. At a stable holding temperature (31–32.5°C), cold receptors had an ongoing periodic discharge of nerve terminal impulses. This activity decreased or ceased with heating and increased with cooling. Reducing the rate of temperature change reduced the respective effects of heating and cooling on nerve terminal impulse frequency. In addition to changes in the frequency of activity, nerve terminal impulse shape also changed with heating and cooling. At the same ambient temperature, nerve terminal impulses were larger in amplitude and faster in time course during heating than those recorded during cooling. The magnitude of these effects of heating and cooling on nerve terminal impulse shape was reduced if the rate of temperature change was slowed. At 29, 31.5, and 35°C, a train of 50 electrical stimuli delivered to the ciliary nerves at 10–40 Hz produced a progressive increase in the amplitude of successive nerve terminal impulses evoked during the train. Therefore, it is unlikely that the reduction in nerve terminal impulse amplitude observed during cooling is due to the activity-dependent changes in the nerve terminal produced by the concomitant increase in impulse frequency. Instead, the differences in nerve terminal impulse shape observed at the same ambient temperature during heating and cooling may reflect changes in the membrane potential of the nerve terminal associated with thermal transduction

    Driving calmodulin protein towards conformational shift by changing ionization states of select residues

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    Proteins are complex systems made up of many conformational sub-states which are mainly determined by the folded structure. External factors such as solvent type, temperature, pH and ionic strength play a very important role in the conformations sampled by proteins. Here we study the conformational multiplicity of calmodulin (CaM) which is a protein that plays an important role in calcium signaling pathways in the eukaryotic cells. CaM can bind to a variety of other proteins or small organic compounds, and mediates different physiological processes by activating various enzymes. Binding of calcium ions and proteins or small organic molecules to CaM induces large conformational changes that are distinct to each interacting partner. In particular, we discuss the effect of pH variation on the conformations of CaM. By using the pKa values of the charged residues as a basis to assign protonation states, the conformational changes induced in CaM by reducing the pH are studied by molecular dynamics simulations. Our current view suggests that at high pH, barrier crossing to the compact form is prevented by repulsive electrostatic interactions between the two lobes. At reduced pH, not only is barrier crossing facilitated by protonation of residues, but also conformations which are on average more compact are attained. The latter are in accordance with the fluorescence resonance energy transfer experiment results of other workers. The key events leading to the conformational change from the open to the compact conformation are (i) formation of a salt bridge between the N-lobe and the linker, stabilizing their relative motions, (ii) bending of the C-lobe towards the N-lobe, leading to a lowering of the interaction energy between the two-lobes, (iii) formation of a hydrophobic patch between the two lobes, further stabilizing the bent conformation by reducing the entropic cost of the compact form, (iv) sharing of a Ca+2 ion between the two lobes

    Superdeformation in 198^{198}Po

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    The 174^{174}Yb(29^{29}Si,5n) reaction at 148 MeV with thin targets was used to populate high-angular momentum states in 198^{198}Po. Resulting γ\gamma rays were observed with Gammasphere. A weakly-populated superdeformed band of 10 γ\gamma-ray transitions was found and has been assigned to 198^{198}Po. This is the first observation of a SD band in the A190A \approx 190 region in a nucleus with Z>83Z > 83. The J(2){\cal J}^{(2)} of the new band is very similar to those of the yrast SD bands in 194^{194}Hg and 196^{196}Pb. The intensity profile suggests that this band is populated through states close to where the SD band crosses the yrast line and the angular momentum at which the fission process dominates.Comment: 10 pages, revtex, 2 figs. available on request, submitted to Phys. Rev. C. (Rapid Communications

    Active Galactic Nuclei under the scrutiny of CTA

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    Active Galactic Nuclei (hereafter AGN) produce powerful outflows which offer excellent conditions for efficient particle acceleration in internal and external shocks, turbulence, and magnetic reconnection events. The jets as well as particle accelerating regions close to the supermassive black holes (hereafter SMBH) at the intersection of plasma inflows and outflows, can produce readily detectable very high energy gamma-ray emission. As of now, more than 45 AGN including 41 blazars and 4 radiogalaxies have been detected by the present ground-based gamma-ray telescopes, which represents more than one third of the cosmic sources detected so far in the VHE gamma-ray regime. The future Cherenkov Telescope Array (CTA) should boost the sample of AGN detected in the VHE range by about one order of magnitude, shedding new light on AGN population studies, and AGN classification and unification schemes. CTA will be a unique tool to scrutinize the extreme high-energy tail of accelerated particles in SMBH environments, to revisit the central engines and their associated relativistic jets, and to study the particle acceleration and emission mechanisms, particularly exploring the missing link between accretion physics, SMBH magnetospheres and jet formation. Monitoring of distant AGN will be an extremely rewarding observing program which will inform us about the inner workings and evolution of AGN. Furthermore these AGN are bright beacons of gamma-rays which will allow us to constrain the extragalactic infrared and optical backgrounds as well as the intergalactic magnetic field, and will enable tests of quantum gravity and other "exotic" phenomena.Comment: 28 pages, 23 figure

    Relative spins and excitation energies of superdeformed bands in 190Hg: Further evidence for octupole vibration

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    An experiment using the Eurogam Phase II gamma-ray spectrometer confirms the existence of an excited superdeformed (SD) band in 190Hg and its very unusual decay into the lowest SD band over 3-4 transitions. The energies and dipole character of the transitions linking the two SD bands have been firmly established. Comparisons with RPA calculations indicate that the excited SD band can be interpreted as an octupole-vibrational structure.Comment: 12 pages, latex, 4 figures available via WWW at http://www.phy.anl.gov/bgo/bc/hg190_nucl_ex.htm
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