13,415 research outputs found

    So what do we do with the rest of the day? Going beyond the pre-shot routine in professional golf

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    Optimally focused attention has been shown to be a key psychological characteristic for peak performance in golf; a feature commonly achieved with a pre-shot routine. However, research to date has yet to address how a golfer’s attention should best shift across the broader period of a whole game, or even including pre-event preparations, to support the pre-shot process and, ultimately, performance. Reflecting this knowledge gap, the present review aims to clarify current conceptual understanding and best practice against this wider perspective on attentional control, as well as highlight areas which must be considered for advances to be made. Specifically, research is required on the cognitive, behavioral, and temporal elements of routines used between shots and holes. Furthermore, to manage the attentional demands of the entire golf performance experience, such investigation also needs to explore the critical role of the support team and pre-tournament planning

    Testing asteroseismology with Gaia DR2: Hierarchical models of the Red Clump

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    Asteroseismology provides fundamental stellar parameters independent of distance, but subject to systematics under calibration. Gaia DR2 has provided parallaxes for a billion stars, which are offset by a parallax zero-point. Red Clump (RC) stars have a narrow spread in luminosity, thus functioning as standard candles to calibrate these systematics. This work measures how the magnitude and spread of the RC in the Kepler field are affected by changes to temperature and scaling relations for seismology, and changes to the parallax zero-point for Gaia. We use a sample of 5576 RC stars classified through asteroseismology. We apply hierarchical Bayesian latent variable models, finding the population level properties of the RC with seismology, and use those as priors on Gaia parallaxes to find the parallax zero-point offset. We then find the position of the RC using published values for the zero-point. We find a seismic temperature insensitive spread of the RC of ~0.03 mag in the 2MASS K band and a larger and slightly temperature-dependent spread of ~0.13 mag in the Gaia G band. This intrinsic dispersion in the K band provides a distance precision of ~1% for RC stars. Using Gaia data alone, we find a mean zero-point of -41 ±\pm 10 μ\muas. This offset yields RC absolute magnitudes of -1.634 ±\pm 0.018 in K and 0.546 ±\pm 0.016 in G. Obtaining these same values through seismology would require a global temperature shift of ~-70 K, which is compatible with known systematics in spectroscopy.Comment: Accepted for publication in MNRA

    Tuning the interactions between electron spins in fullerene-based triad systems

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    A series of six fullerene-linker-fullerene triads have been prepared by the stepwise addition of the fullerene cages to bridging moieties thus allowing the systematic variation of fullerene cage (C60 or C70) and linker (oxalate or terephthalate) and enabling precise control over the inter-fullerene separation. The fullerene triads exhibit good solubility in common organic solvents, have linear geometries and are diastereomerically pure. Cyclic voltammetric measurements demonstrate the excellent electron accepting capacity of all triads, with up to 6 electrons taken up per molecule in the potential range between -2.3 and 0.2 V (vs. Fc+/Fc). No significant electronic interactions between fullerene cages are observed in the ground state indicating that the individual properties of each C60 or C70 cage are retained within the triads. The electron-electron interactions in the electrochemically generated dianions of these triads, with one electron per fullerene cage were studied by EPR spectroscopy. The nature of electron-electron coupling observed at 77 K can be described as an equilibrium between a doublet and triplet state biradical which depends on the interfullerene spacing. The shorter oxalate-bridged triads exhibit stronger spin-spin coupling with triplet character, while in the longer terephthalate-bridged triads the intramolecular spin-spin coupling is significantly reduced

    Identification of a Core Amino Acid Motif within the α Subunit of GABAARs that Promotes Inhibitory Synaptogenesis and Resilience to Seizures

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    The fidelity of inhibitory neurotransmission is dependent on the accumulation of γ-aminobutyric acid type A receptors (GABAARs) at the appropriate synaptic sites. Synaptic GABAARs are constructed from α(1-3), β(1-3), and γ2 subunits, and neurons can target these subtypes to specific synapses. Here, we identify a 15-amino acid inhibitory synapse targeting motif (ISTM) within the α2 subunit that promotes the association between GABAARs and the inhibitory scaffold proteins collybistin and gephyrin. Using mice in which the ISTM has been introduced into the α1 subunit (Gabra1-2 mice), we show that the ISTM is critical for axo-axonic synapse formation, the efficacy of GABAergic neurotransmission, and seizure sensitivity. The Gabra1-2 mutation rescues seizure-induced lethality in Gabra2-1 mice, which lack axo-axonic synapses due to the deletion of the ISTM from the α2 subunit. Taken together, our data demonstrate that the ISTM plays a critical role in promoting inhibitory synapse formation, both in the axonic and somatodendritic compartments

    Renewable fuel production from hydropyrolysis of residual biomass using molybdenum carbide-based catalysts: An analytical Py-GC/MS investigation

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    Fast hydropyrolysis of lignocellulosic biomass was studied by using an analytical pyrolyzer coupled with a gas chromatography/mass spectrometry set-up (Py-GC/MS). Under pure H2 stream, Canadian pinewood was rapidly heated up to 500 °C and the generated vapors passed through a catalytic bed at 500 °C. Experiments were carried out in order to compare the catalytic performance of MoC/Al2O3 catalyst to a reference catalyst based on noble metal (1.5 wt.% Pt/Al2O3). The effect of different supports (Al2O3, ZrO2 and MgO) on the carbide performance and product formation was investigated. The results showed that the performance of MoC/Al2O3 was similar to that of 1.5 wt.% Pt/Al2O3. Both of them deoxygenated the hydropyrolysis vapors and led exclusively to hydrocarbons formation. However, the proportion of aliphatic and aromatic hydrocarbons was different: MoC/Al2O3 catalyst produced more aliphatics (57%) than the Pt catalyst. The supports have demonstrated influence on the product distribution. Acidity of the support seems to play an important role in the deoxygenation of the vapors. While there was complete removal of oxygen when MoC/Al2O3 and MoC/ZrO2 were used, the same did not take place for the more basic MoC/MgO catalyst

    Effects of Vacuum Fluctuation Suppression on Atomic Decay Rates

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    The use of atomic decay rates as a probe of sub-vacuum phenomena will be studied. Because electromagnetic vacuum fluctuations are essential for radiative decay of excited atomic states, decay rates can serve as a measure of the suppression of vacuum fluctuation in non-classical states, such as squeezed vacuum states. In such states the renormalized expectation value of the square of the electric field or the energy density can be periodically negative, representing suppression of vacuum fluctuations. We explore the extent to which atomic decays can be used to measure the mean squared electric field or energy density. We consider a scheme in which atoms in an excited state transit a closed cavity whose lowest mode contains photons in a non-classical state. The change in the decay probability of the atom in the cavity due to the non-classical state can, under certain circumstances, serve as a measure of the mean squared electric field or energy density in the cavity. We derive a quantum inequality bound on the decrease in this probability. We also show that the decrease in decay rate can sometimes be a measure of negative energy density or negative squared electric field. We make some estimates of the magnitude of this effect, which indicate that an experimental test might be possible.Comment: 19 pages, 3 figure

    NGC 346 in the Small Magellanic Cloud. III. Recent Star Formation and Stellar Clustering Properties in the Bright HII Region N 66

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    In the third part of our photometric study of the star-forming region NGC 346/N~66 and its surrounding field in the Small Magellanic Cloud (SMC), we focus on the large number of low-mass pre-main sequence (PMS) stars revealed by the Hubble Space Telescope Observations with the Advanced Camera for Surveys. We investigate the origin of the observed broadening of the pre-main sequence population in the VIV-I, VV CMD. The most likely explanations are either the presence of differential reddening or an age spread among the young stars. Assuming the latter, simulations indicate that we cannot exclude the possibility that stars in NGC 346 might have formed in two distinct events occurring about 10 and 5 Myr ago, respectively. We find that the PMS stars are not homogeneously distributed across NGC 346, but instead are grouped in at least five different clusters. On spatial scales from 0.8'' to 8'' (0.24 to 2.4 pc at the distance of the SMC) the clustering of the PMS stars as computed by a two-point angular correlation function is self-similar with a power law slope γ0.3\gamma \approx -0.3. The clustering properties are quite similar to Milky Way star forming regions like Orion OB or ρ\rho Oph. Thus molecular cloud fragmentation in the SMC seems to proceed on the same spatial scales as in the Milky Way. This is remarkable given the differences in metallicity and hence dust content between SMC and Milky Way star forming regions.Comment: Accepted for publication in ApJ. 16 pages, 13 (low-resolution) figures, emulateapj.cls LaTeX styl
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