675 research outputs found

    THE APPLICATION OF A SPORT-SPECIFIC 3D STEREOSCOPIC STIMULUS TO EXAMINE PRE-PLANNING TIME AND GAZE CHARACTERISTICS DURING EVASIVE SIDE-STEPPING MANOEUVRES

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    It is well established that anterior cruciate ligament (ACL) injuries are serious, debilitating and costly for an individual, while also creating a significant public health burden at a societal level. ACL injuries occur when inappropriate external loads are applied to the knee and most commonly occur during the performance of a side-stepping (Ssg) manoeuvre (Besier et al., 2001a). Previous laboratory based investigations of evasive Ssg have employed generic light or mannequin visual stimuli in an effort to simulate the time and space constraints experienced by athletes, in the preparation and execution of the Ssg manoeuvre (Besier et al., 2001b; Besier et al., 2003; Mclean et al., 2004). However, a possible outcome of attempts to impose these constraints in lab environments is that the use of unrealistic visual stimuli may not accurately reflect or identify the relationship of the perceptual demands of the task with injury risk variables, during a sidestep in game based situations. This study proposes that the presentation of a three dimensional (3D) stereoscopic stimulus (3DSS), featuring a 3D video based sport specific reconstruction of an opposing defender(s) simulating a tackle, may improve the ecological validity of laboratory based investigations. Additionally, the incorporation of the 3DSS tool with eye tracking will allow for the subject’s gaze characteristics (fixations, durations on the 3DSS image) to be assessed. The general aims of this study were to: Technical • develop a 3DSS that delivers realistic sport-specific constraints to footballers during evasive Ssg manoeuvres, • create 3DSS scenarios that incorporate realistic game based variations of imposed time and space constraints (e.g. 3DSS tackle scenarios with one or two defenders), • develop an interface and protocol that integrates the 3DSS system with a commercial eye tracking system (ASL Eye Tracking Recorder), for the purpose of quantifying the lab based subject’s gaze characteristics on the projected stimulus during a Ssg manoeuvre, Experimental • identify differences in biomechanical variables (kinematic, kinetic and neuromuscular) associated with increased injury risk during Ssg manoeuvres, using a traditional light (light emitting diode) based stimulus (LBSS) compared with a 3DSS stimuli

    Harnessing ChatGPT for thematic analysis: Are we ready?

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    ChatGPT is an advanced natural language processing tool with growing applications across various disciplines in medical research. Thematic analysis, a qualitative research method to identify and interpret patterns in data, is one application that stands to benefit from this technology. This viewpoint explores the utilization of ChatGPT in three core phases of thematic analysis within a medical context: 1) direct coding of transcripts, 2) generating themes from a predefined list of codes, and 3) preprocessing quotes for manuscript inclusion. Additionally, we explore the potential of ChatGPT to generate interview transcripts, which may be used for training purposes. We assess the strengths and limitations of using ChatGPT in these roles, highlighting areas where human intervention remains necessary. Overall, we argue that ChatGPT can function as a valuable tool during analysis, enhancing the efficiency of the thematic analysis and offering additional insights into the qualitative data.Comment: 23 pages, 7 figures, 3 tables, 1 textbo

    Outflow, Infall and Protostars in the Star Forming Core W3-SE

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    We report new results on outflow and infall in the star forming cores W3-SE SMA-1 and SMA-2 based on analysis of \sim2.5\arcsec resolution observations of the molecular lines HCN(3-2), HCO+^+(3-2), N2_2H+^+(3-2) and CH3_3OH(52,341,3_{2,3}-4_{1,3}) with the Submillimeter Array. A high-velocity bipolar outflow originating from the proto-stellar core SMA-1 was observed in the HCN(3-2) line, with a projected outflow axis in position angle 48\arcdeg. The detection of the outflow is confirmed from other molecular lines. An inverse P-Cygni profile in the HCN(3-2) line toward SMA-1 suggests that at least one of the double cores accretes matters from the molecular core. A filamentary structure in the molecular gas surrounds SMA-1 and SMA-2. Based on the SMA observations, our analysis suggests that the double pre-stellar cores SMA-1 and SMA-2 result from fragmentation in the collapsing massive molecular core W3-SE, and it is likely that they are forming intermediate to high-mass stars which will be new members of a star cluster in the W3-SE region.Comment: 16 pages, 11 figure

    Comparing star formation models with interferometric observations of the protostar NGC 1333 IRAS 4A. I. Magnetohydrodynamic collapse models

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    Observations of dust polarized emission toward star forming regions trace the magnetic field component in the plane of the sky and provide constraints to theoretical models of cloud collapse. We compare high-angular resolution observations of the submillimeter polarized emission of the low-mass protostellar source NGC 1333 IRAS 4A with the predictions of three different models of collapse of magnetized molecular cloud cores. We compute the Stokes parameters for the dust emission for the three models. We then convolve the results with the instrumental response of the Submillimeter Array observation toward IRAS 4A. Finally, we compare the synthetic maps with the data, varying the model parameters and orientation, and we assess the quality of the fit by a \chi^2 analysis. High-angular resolution observations of polarized dust emission can constraint the physical properties of protostars. In the case of IRAS 4A, the best agreements with the data is obtained for models of collapse of clouds with mass-to-flux ratio >2 times the critical value, initial uniform magnetic field of strength ~0.5 mG, and age of the order of a few 10^4 yr since the onset of collapse. Magnetic dissipation, if present, is found to occur below the resolution level of the observations. Including a previously measured temperature profile of IRAS 4A leads to a more realistic morphology and intensity distribution. We also show that ALMA has the capability of distinguishing among the three different models adopted in this work. Our results are consistent with the standard theoretical scenario for the formation of low-mass stars, where clouds initially threaded by large-scale magnetic fields become unstable and collapse, trapping the field in the nascent protostar and the surrounding circumstellar disk. In the collapsing cloud, the dynamics is dominated by gravitational and magnetic forces.Comment: Accepted for publication in Astronomy And Astrophysics. 14 pages, 11 figures, 3 tables. Several the figures are shown at low resolutio

    Water emission in NGC1333-IRAS4: The physical structure of the envelope

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    We report ISO-LWS far infrared observations of CO, water and oxygen lines towards the protobinary system IRAS4 in the NGC1333 cloud. We detected several water, OH, CO rotational lines, and two [OI] and [CII] fine structure lines. Given the relatively poor spectral and spatial resolution of these observations, assessing the origin of the observed emission is not straightforward. In this paper, we focus on the water line emission and explore the hypothesis that it originates in the envelopes that surround the two protostars, IRAS4 A and B, thanks to an accurate model. The model reproduces quite well the observed water line fluxes, predicting a density profile, mass accretion rate, central mass, and water abundance profile in agreement with previous works. We hence conclude that the emission from the envelopes is a viable explanation for the observed water emission, although we cannot totally rule out the alternative that the observed water emission originates in the outflow

    Degenerate Rotating Black Holes, Chiral CFTs and Fermi Surfaces I - Analytic Results for Quasinormal Modes

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    In this work we discuss charged rotating black holes in AdS5×S5AdS_5 \times S^5 that degenerate to extremal black holes with zero entropy. These black holes have scaling properties between charge and angular momentum similar to those of Fermi surface operators in a subsector of N=4\mathcal{N}=4 SYM. We add a massless uncharged scalar to the five dimensional supergravity theory, such that it still forms a consistent truncation of the type IIB ten dimensional supergravity and analyze its quasinormal modes. Separating the equation of motion to a radial and angular part, we proceed to solve the radial equation using the asymptotic matching expansion method applied to a Heun equation with two nearby singularities. We use the continued fraction method for the angular Heun equation and obtain numerical results for the quasinormal modes. In the case of the supersymmetric black hole we present some analytic results for the decay rates of the scalar perturbations. The spectrum of quasinormal modes obtained is similar to that of a chiral 1+1 CFT, which is consistent with the conjectured field-theoretic dual. In addition, some of the modes can be found analytically.Comment: 41 pages, 1 figure, LaTeX; v2: typos corrected, references adde

    Sum rules and electrodynamics of high-Tc cuprates in the pseudogap state

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    We explore connections between the electronic density of states (DOS) in a conducting system and the frequency dependence of the scattering rate 1/τ(ω)1/\tau(\omega) inferred from infrared spectroscopy. We show that changes in the DOS upon the development of energy gaps can be reliably tracked through the examination of the 1/τ(ω)1/\tau(\omega) spectra using the sum rules discussed in the text. Applying this analysis to the charge dynamics in high-TcT_c cuprates we found radically different trends in the evolution of the DOS in the pseudogap state and in the superconducting state.Comment: 4 pages, 3 figure

    "I'll look after my health, later": A replication and extension of the procrastination-health model with community-dwelling adults

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    Initial investigations into the links between procrastination and health in student samples implicated stress-related and behavioural pathways. However, it is unknown if these relations are the same for community-dwelling adults, or if alternative measures of procrastination and health behaviors will yield the same results. To replicate and extend previous findings 254 adults recruited from the community and the Internet completed self-report measures of procrastination, health, stress, wellness and household safety behaviours. Consistent with previous work, procrastination was associated with higher stress, more acute health problems, and the practice of fewer wellness behaviours. Procrastinators also reported fewer household safety behaviours, and less frequent dental and medical check-ups. The structural equation modeling analyses revealed that stress fully mediated the procrastination–health relationship, but health behaviours did not when the combined effect with stress was considered. These findings suggest that in addition to hindering a variety of health-related behaviours, procrastination may confer additional risk for increased stress, and consequently more health problems

    Measurement of the rate of nu_e + d --> p + p + e^- interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory

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    Solar neutrinos from the decay of 8^8B have been detected at the Sudbury Neutrino Observatory (SNO) via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons. The CC reaction is sensitive exclusively to nu_e's, while the ES reaction also has a small sensitivity to nu_mu's and nu_tau's. The flux of nu_e's from ^8B decay measured by the CC reaction rate is \phi^CC(nu_e) = 1.75 +/- 0.07 (stat)+0.12/-0.11 (sys.) +/- 0.05(theor) x 10^6 /cm^2 s. Assuming no flavor transformation, the flux inferred from the ES reaction rate is \phi^ES(nu_x) = 2.39+/-0.34 (stat.)+0.16}/-0.14 (sys) x 10^6 /cm^2 s. Comparison of \phi^CC(nu_e) to the Super-Kamiokande Collaboration's precision value of \phi^ES(\nu_x) yields a 3.3 sigma difference, providing evidence that there is a non-electron flavor active neutrino component in the solar flux. The total flux of active ^8B neutrinos is thus determined to be 5.44 +/-0.99 x 10^6/cm^2 s, in close agreement with the predictions of solar models.Comment: 6 pages (LaTex), 3 figures, submitted to Phys. Rev. Letter
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