A SURROGATE METHOD FOR DISCRETE MOVEMENT DATA

Sample entropy can be an effective tool for the investigation of human movement variability. However, before applying the method, it can be beneficial to employ an analysis to confirm that observed data is not solely the result of stochastic processes. This can be achieved using surrogate methods. Previous investigations have used surrogate methods within human gait data, yet no appropriate method has been applied to discrete human movement. This article proposes a surrogate method for discrete movement data. The technique reliably generated surrogates for discrete joint angle time series, effectively destroying fine-scale dynamics of the observed signal and maintaining macro structural characteristics (e.g., Mean, SD). Comparison of entropy estimates indicated that observed signals contained deterministic dynamics

CHANGES IN MOVEMENT REGULARITY DURING LEARNING OF A NOVEL DISCRETE TASK

Sample entropy and surrogate methods were employed to investigate changes in regularity of movement profiles during the learning of a novel discrete task under contextual interference conditions by two groups. The contextual interference effect was confirmed. Surrogate methods were used to show the presence of deterministic dynamics in observed data. Trends of decreased and increased movement regularity for groups 1 and 2 respectively were observed. The relative stage of learning and the ability to operate within an acceptable range of variability/complexity may explain these trends. Entropy estimates as a measure of regularity may provide important information about the learning of discrete tasks

INVESTIGATING THE RELATIONSHIP BETWEEN MOVEMENT VARIABILITY, SKILL ACQUISITION AND ADAPTABILITY

Facilitating adaptability is a role attributed to movement variability. The aim of this investigation was to track changes in movement variability during the learning of a novel task where adaptability was expected to be present. A contextual interference design was implemented with sample entropy and vector coding used to quantify joint and coordination variability respectively. Those exposed to high contextual interference were significantly better performed and more adaptable. Significant decreases in coordination variability were found during the learning process for all participants. The more adaptable group also exhibited higher coordination variability at key points providing some support for previous hypotheses on the interaction between, skill acquisition and adaptability. Results have implications for practitioners working in skill acquisition

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom

First searches for optical counterparts to gravitational-wave candidate events

During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

FIRST SEARCHES FOR OPTICAL COUNTERPARTS TO GRAVITATIONAL-WAVE CANDIDATE EVENTS

During the LIGO and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

Searching for stochastic gravitational waves using data from the two colocated LIGO Hanford detectors

Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a colocated detector pair is more sensitive to a gravitational-wave background than a noncolocated detector pair. However, colocated detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of colocated detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO’s fifth science run. At low frequencies, 40–460 Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460–1000 Hz, these techniques are sufficient to set a 95% confidence level upper limit on the gravitational-wave energy density of Ω(f) < 7.7 × 10[superscript -4](f/900  Hz)[superscript 3], which improves on the previous upper limit by a factor of ~180. In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustDavid & Lucile Packard FoundationAlfred P. Sloan Foundatio

Search for long-lived gravitational-wave transients coincident with long gamma-ray bursts

Long gamma-ray bursts (GRBs) have been linked to extreme core-collapse supernovae from massive stars. Gravitational waves (GW) offer a probe of the physics behind long GRBs. We investigate models of long-lived (~10–1000 s) GW emission associated with the accretion disk of a collapsed star or with its protoneutron star remnant. Using data from LIGO’s fifth science run, and GRB triggers from the Swift experiment, we perform a search for unmodeled long-lived GW transients. Finding no evidence of GW emission, we place 90% confidence-level upper limits on the GW fluence at Earth from long GRBs for three waveforms inspired by a model of GWs from accretion disk instabilities. These limits range from F<3:5 ergs cm⁻2 to F<1200 ergs cm⁻2, depending on the GRB and on the model, allowing us to probe optimistic scenarios of GW production out to distances as far as ≈ 33 Mpc. Advanced detectors are expected to achieve strain sensitivities 10× better than initial LIGO, potentially allowing us to probe the engines of the nearest long GRBs.J. Aasi ... D.J. Hosken ... W. Kim ... E.J. King ... J. Munch ... D. J. Ottaway ... P. J. Veitc

A Hypothetical Case Formulation Using Event-Meaning Coupling to Promote Insight into Chronic Pain Experience

The goal of rehabilitating individuals with chronic pain is to assist them in reclaiming control over their pain management and channeling their focus towards well-being and improving function. By providing rational information that helps patients understand their pain, their distress can be alleviated, resulting in positive changes in both their emotional and behavioral responses. Practitioners can assist patients in comprehending their pain and developing an effective management plan by employing a case formulation model. Within the cognitive behavioral model of chronic pain, event-meaning coupling can be emphasized in case formulation, allowing for a greater focus on the patient’s internal cognitive processes, helping them gaining insight into their pain. This model also considers potential biopsychosocial factors that could afford the patient’s ability to make new meaning from events. By assessing and promoting positive event-meaning couplings, patients can be empowered to interact more effectively with their biopsychosocial arena, which in turn can foster a virtuous cycle for self-expansion for successful rehabilitation