871 research outputs found

    Acute stress affects peripersonal space representation in cortisol stress responders.

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    Peripersonal space is the representation of the space near the body. It is implemented by a dedicated multisensory-motor network, whose purpose is to predict and plan interactions with the environment, and which can vary depending on environmental circumstances. Here, we investigated the effect on the PPS representation of an experimentally induced stress response and compared it to a control, non-stressful, manipulation. We assessed PPS representation in healthy humans, before and after a stressful manipulation, by quantifying visuotactile interactions as a function of the distance from the body, while monitoring salivary cortisol concentration. While PPS representation was not significantly different between the control and experimental group, a relation between cortisol response and changes in PPS emerged within the experimental group. Participants who showed a cortisol stress response presented enhanced visuotactile integration for stimuli close to the body and reduced for far stimuli. Conversely, individuals with a less pronounced cortisol response showed a reduced difference in visuotactile integration between the near and the far space. In our interpretation, physiological stress resulted in a freezing-like response, where multisensory-motor resources are allocated only to the area immediately surrounding the body

    Synaptic and extrasynaptic NMDA receptors are gated by different endogenous coagonists.

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    N-methyl-D-aspartate receptors (NMDARs) are located in neuronal cell membranes at synaptic and extrasynaptic locations, where they are believed to mediate distinct physiological and pathological processes. Activation of NMDARs requires glutamate and a coagonist whose nature and impact on NMDAR physiology remain elusive. We report that synaptic and extrasynaptic NMDARs are gated by different endogenous coagonists, D-serine and glycine, respectively. The regionalized availability of the coagonists matches the preferential affinity of synaptic NMDARs for D-serine and extrasynaptic NMDARs for glycine. Furthermore, glycine and D-serine inhibit NMDAR surface trafficking in a subunit-dependent manner, which is likely to influence NMDARs subcellular location. Taking advantage of this coagonist segregation, we demonstrate that long-term potentiation and NMDA-induced neurotoxicity rely on synaptic NMDARs only. Conversely, long-term depression requires both synaptic and extrasynaptic receptors. Our observations provide key insights into the operating mode of NMDARs, emphasizing functional distinctions between synaptic and extrasynaptic NMDARs in brain physiology

    Results of the minimally invasive coronary artery bypass grafting angiographic patency study

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    ObjectiveMinimally invasive coronary artery bypass grafting is safe and widely applicable, and may be associated with fewer transfusions and infections, and better recovery than standard coronary artery bypass grafting. However, graft patency rates remain unknown. The Minimally Invasive Coronary Artery Bypass Grafting Patency Study prospectively evaluated angiographic graft patency 6 months after minimally invasive coronary artery bypass grafting.MethodsIn this dual-center study, 91 patients were prospectively enrolled to undergo minimally invasive coronary artery bypass grafting via a 4- to 7-cm left thoracotomy approach. The left internal thoracic artery, the ascending aorta for proximal anastomoses, and all coronary targets were directly accessed without endoscopic or robotic assistance. The study primary outcome was graft patency at 6 months, using 64-slice computed tomography angiography. Secondary outcomes included conversions to sternotomy and major adverse cardiovascular events (Clinical Trial Registration Unique identifier: NCT01334866).ResultsThe mean age of patients was 64 ± 8 years, the mean ejection fraction was 51% ± 11%, and there were 10 female patients (11%) in the study. Surgeries were performed entirely off-pump in 68 patients (76%). Complete revascularization was achieved in all patients, and the median number of grafts was 3. There was no perioperative mortality, no conversion to sternotomy, and 2 reopenings for bleeding. Transfusion occurred in 24 patients (26%). The median length of hospital stay was 4 days, and all patients were followed to 6 months, with no mortality or major adverse cardiovascular events. Six-month computed tomography angiographic graft patency was 92% for all grafts and 100% for left internal thoracic artery grafts.ConclusionsMinimally invasive coronary artery bypass grafting is safe, feasible, and associated with excellent outcomes and graft patency at 6 months post-surgery

    Ring closing reaction in diarylethene captured by femtosecond electron crystallography

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    The photoinduced ring-closing reaction in diarylethene, which serves as a model system for understanding reactive crossings through conical intersections, was directly observed with atomic resolution using femtosecond electron diffraction. Complementary ab initio calculations were also performed. Immediately following photoexcitation, subpicosecond structural changes associated with the formation of an open-ring excited-state intermediate were resolved. The key motion is the rotation of the thiophene rings, which significantly decreases the distance between the reactive carbon atoms prior to ring closing. Subsequently, on the few picosecond time scale, localized torsional motions of the carbon atoms lead to the formation of the closed-ring photoproduct. These direct observations of the molecular motions driving an organic chemical reaction were only made possible through the development of an ultrabright electron source to capture the atomic motions within the limited number of sampling frames and the low data acquisition rate dictated by the intrinsically poor thermal conductivity and limited photoreversibility of organic materials

    Exposure to Mass Media and Interpersonal Counseling Has Additive Effects on Exclusive Breastfeeding and Its Psychosocial Determinants Among Vietnamese Mothers

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    The pathways through which behavior change interventions impact breastfeeding practices have not been well studied. This study aimed to examine: (1) the effects of exposure to mass media and interpersonal counseling on exclusive breastfeeding (EBF) and hypothesized psychosocial determinants (i.e. knowledge, intention, beliefs, social norms, and self-efficacy); and (2) the pathways through which exposure to mass media and interpersonal counseling are associated with EBF. We used survey data from mothers with children\u3c 2 year (n = 2045) from the 2013 process evaluation of Alive & Thrive’s program in Viet Nam. Multiple linear regression analyses and structural equation modeling were used to estimate effects. Exposure to mass media only, interpersonal counseling only, both or neither was 51%, 5%, 19% and 25%, respectively. Exposure to both mass media and interpersonal counseling had additive effects on EBF as well as on related psychosocial factors, compared with no exposure. For example, EBF prevalence was 26.1 percentage points (pp) higher in the group that received interpersonal counseling only, 3.9 pp higher in the mass media group and 31.8 pp higher in the group that received both interventions. As hypothesized, more than 90% of the total effect of the two interventions on EBF was explained by the psychosocial factors measured. Our findings suggest that combining different behavior change interventions leads to greater changes in psychosocial factors, which in turn positively affects breastfeeding behaviors

    South Pole Telescope Detections of the Previously Unconfirmed Planck Early SZ Clusters in the Southern Hemisphere

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    We present South Pole Telescope (SPT) observations of the five galaxy cluster candidates in the southern hemisphere which were reported as unconfirmed in the Planck Early Sunyaev-Zel'dovich (ESZ) sample. One cluster candidate, PLCKESZ G255.62-46.16, is located in the 2500-square-degree SPT SZ survey region and was reported previously as SPT-CL J0411-4819. For the remaining four candidates, which are located outside of the SPT SZ survey region, we performed short, dedicated SPT observations. Each of these four candidates was strongly detected in maps made from these observations, with signal-to-noise ratios ranging from 6.3 to 13.8. We have observed these four candidates on the Magellan-Baade telescope and used these data to estimate cluster redshifts from the red sequence. Resulting redshifts range from 0.24 to 0.46. We report measurements of Y_0.75', the integrated Comptonization within a 0.75' radius, for all five candidates. We also report X-ray luminosities calculated from ROSAT All-Sky Survey catalog counts, as well as optical and improved SZ coordinates for each candidate. The combination of SPT SZ measurements, optical red-sequence measurements, and X-ray luminosity estimates demonstrates that these five Planck ESZ cluster candidates do indeed correspond to real galaxy clusters with redshifts and observable properties consistent with the rest of the ESZ sample.Comment: 7 emulateapj pages, 4 figures, 1 table. Revised to match published versio

    Mass Calibration and Cosmological Analysis of the SPT-SZ Galaxy Cluster Sample Using Velocity Dispersion σv\sigma_v and X-ray YXY_\textrm{X} Measurements

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    We present a velocity dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg2 of the survey along with 63 velocity dispersion (σv\sigma_v) and 16 X-ray Yx measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. The calibrations using σv\sigma_v and Yx are consistent at the 0.6σ0.6\sigma level, with the σv\sigma_v calibration preferring ~16% higher masses. We use the full cluster dataset to measure σ8(Ωm/0.27)0.3=0.809±0.036\sigma_8(\Omega_ m/0.27)^{0.3}=0.809\pm0.036. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming the sum of the neutrino masses is mν=0.06\sum m_\nu=0.06 eV, we find the datasets to be consistent at the 1.0σ\sigma level for WMAP9 and 1.5σ\sigma for Planck+WP. Allowing for larger mν\sum m_\nu further reconciles the results. When we combine the cluster and Planck+WP datasets with BAO and SNIa, the preferred cluster masses are 1.9σ1.9\sigma higher than the Yx calibration and 0.8σ0.8\sigma higher than the σv\sigma_v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness of fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe dataset, we measure Ωm=0.299±0.009\Omega_ m=0.299\pm0.009 and σ8=0.829±0.011\sigma_8=0.829\pm0.011. Within a ν\nuCDM model we find mν=0.148±0.081\sum m_\nu = 0.148\pm0.081 eV. We present a consistency test of the cosmic growth rate. Allowing both the growth index γ\gamma and the dark energy equation of state parameter ww to vary, we find γ=0.73±0.28\gamma=0.73\pm0.28 and w=1.007±0.065w=-1.007\pm0.065, demonstrating that the expansion and the growth histories are consistent with a LCDM model (γ=0.55;w=1\gamma=0.55; \,w=-1).Comment: Accepted by ApJ (v2 is accepted version); 17 pages, 6 figure

    Optical Spectroscopy and Velocity Dispersions of Galaxy Clusters from the SPT-SZ Survey

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    We present optical spectroscopy of galaxies in clusters detected through the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). We report our own measurements of 6161 spectroscopic cluster redshifts, and 4848 velocity dispersions each calculated with more than 1515 member galaxies. This catalog also includes 1919 dispersions of SPT-observed clusters previously reported in the literature. The majority of the clusters in this paper are SPT-discovered; of these, most have been previously reported in other SPT cluster catalogs, and five are reported here as SPT discoveries for the first time. By performing a resampling analysis of galaxy velocities, we find that unbiased velocity dispersions can be obtained from a relatively small number of member galaxies (30\lesssim 30), but with increased systematic scatter. We use this analysis to determine statistical confidence intervals that include the effect of membership selection. We fit scaling relations between the observed cluster velocity dispersions and mass estimates from SZ and X-ray observables. In both cases, the results are consistent with the scaling relation between velocity dispersion and mass expected from dark-matter simulations. We measure a \sim30% log-normal scatter in dispersion at fixed mass, and a \sim10% offset in the normalization of the dispersion-mass relation when compared to the expectation from simulations, which is within the expected level of systematic uncertainty.Comment: Accepted to ApJ. 20 pages, 6 figure
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