9,175 research outputs found

    On the time lags of the LIGO signals

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    To date, the LIGO collaboration has detected three gravitational wave (GW) events appearing in both its Hanford and Livingston detectors. In this article we reexamine the LIGO data with regard to correlations between the two detectors. With special focus on GW150914, we report correlations in the detector noise which, at the time of the event, happen to be maximized for the same time lag as that found for the event itself. Specifically, we analyze correlations in the calibration lines in the vicinity of 35\,Hz as well as the residual noise in the data after subtraction of the best-fit theoretical templates. The residual noise for the other two events, GW151226 and GW170104, exhibits similar behavior. A clear distinction between signal and noise therefore remains to be established in order to determine the contribution of gravitational waves to the detected signals.Comment: The body of the current version is essentially identical to the previous one submitted to arxiv and JCAP. In order to meet the various suggestions of the referees, we have included an extended and detailed Appendix. This Appendix also contains significant new results that provide additional support for our conclusions. This version of our manuscript has been accepted for publication by JCA

    Degeneracy of gravitational waveforms in the context of GW150914

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    We study the degeneracy of theoretical gravitational waveforms for binary black hole mergers using an aligned-spin effective-one-body model. After appropriate truncation, bandpassing, and matching, we identify regions in the mass--spin parameter space containing waveforms similar to the template proposed for GW150914, with masses m1=364+5Mm_1 = 36^{+5}_{-4} M_\odot and m2=294+4Mm_2 = 29^{+4}_{-4} M_\odot, using the cross-correlation coefficient as a measure of the similarity between waveforms. Remarkably high cross-correlations are found across broad regions of parameter space. The associated uncertanties exceed these from LIGO's Bayesian analysis considerably. We have shown that waveforms with greatly increased masses, such as m1=70Mm_1 = 70 M_\odot and m2=35Mm_2 = 35 M_\odot, and strong anti-aligned spins (χ1=0.95\chi_1=0.95 and χ2=0.95\chi_2=-0.95) yield almost the same signal-to-noise ratio in the strain data for GW150914.Comment: Accepted for publication in JCA

    Development of quantum perspectives in modern physics

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    Introductory undergraduate courses in classical physics stress a perspective that can be characterized as realist; from this perspective, all physical properties of a classical system can be simultaneously specified and thus determined at all future times. Such a perspective can be problematic for introductory quantum physics students, who must develop new perspectives in order to properly interpret what it means to have knowledge of quantum systems. We document this evolution in student thinking in part through pre- and post-instruction evaluations using the Colorado Learning Attitudes about Science Survey. We further characterize variations in student epistemic and ontological commitments by examining responses to two essay questions, coupled with responses to supplemental quantum attitude statements. We find that, after instruction in modern physics, many students are still exhibiting a realist perspective in contexts where a quantum-mechanical perspective is needed. We further find that this effect can be significantly influenced by instruction, where we observe variations for courses with differing learning goals. We also note that students generally do not employ either a realist or a quantum perspective in a consistent manner.Comment: 18 pages, plus references; 3 figures; 9 tables. PACS: 01.40.Fk, 03.65._

    Factors affecting continuation of clean intermittent catheterisation in people with multiple sclerosis: results of the COSMOS mixed-methods study

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    Background:  Clean intermittent catheterisation (CIC) is often recommended for people with multiple sclerosis (MS).  Objective:  To determine the variables that affect continuation or discontinuation of the use of CIC.  Methods:  A three-part mixed-method study (prospective longitudinal cohort (n = 56), longitudinal qualitative interviews (n = 20) and retrospective survey (n = 456)) was undertaken, which identified the variables that influenced CIC continuation/discontinuation. The potential explanatory variables investigated in each study were the individual’s age, gender, social circumstances, number of urinary tract infections, bladder symptoms, presence of co-morbidity, stage of multiple sclerosis and years since diagnosis, as well as CIC teaching method and intensity.  Results:  For some people with MS the prospect of undertaking CIC is difficult and may take a period of time to accept before beginning the process of using CIC. Ongoing support from clinicians, support at home and a perceived improvement in symptoms such as nocturia were positive predictors of continuation. In many cases, the development of a urinary tract infection during the early stages of CIC use had a significant detrimental impact on continuation.  Conclusion:  Procedures for reducing the incidence of urinary tract infection during the learning period (i.e. when being taught and becoming competent) should be considered, as well as the development of a tool to aid identification of a person’s readiness to try CIC

    Food activities and identity maintenance in old age: a systematic review and meta-synthesis

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    This article has been made available through the Brunel Open Access Publishing Fund.Objectives: Services provided to older people should be developed based on active ageing policies. Nutrition is one aspect of active ageing, but little is known about how food activities contribute to psychological well-being in later life. This is a systematic review of qualitative and quantitative research that answers the question ‘What is known about the relationship between food activities and the maintenance of identities in old age?’

    Self-Affirmation Improves Problem-Solving under Stress

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    High levels of acute and chronic stress are known to impair problem-solving and creativity on a broad range of tasks. Despite this evidence, we know little about protective factors for mitigating the deleterious effects of stress on problem-solving. Building on previous research showing that self-affirmation can buffer stress, we tested whether an experimental manipulation of self-affirmation improves problem-solving performance in chronically stressed participants. Eighty undergraduates indicated their perceived chronic stress over the previous month and were randomly assigned to either a self-affirmation or control condition. They then completed 30 difficult remote associate problem-solving items under time pressure in front of an evaluator. Results showed that self-affirmation improved problem-solving performance in underperforming chronically stressed individuals. This research suggests a novel means for boosting problem-solving under stress and may have important implications for understanding how self-affirmation boosts academic achievement in school settings. © 2013 Creswell et al

    The politics, fashions, and conventions of research methods.

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    The results of an empirical study of any set of phenomena, whether investigating structures, processes, or combinations thereof, are influenced by the theoretical framework as well as the research methods employed. This text examines the influence of research methods on how phenomena under investigation are conceptualized, defined, measured, and interpreted. It will be argued that qualitative, quantitative, and, by extension, mixed methods research influence how phenomena are studied, and how these methods are concurrently subject to politics, fashions, and conventions. Inconsistent and impoverished research may be the consequence, particularly for mixed methods research

    "How do pilates trained physiotherapists utilize and value pilates exercise for MSK conditions? A qualitative study"

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    Background Pilates is a popular exercise therapy approach offering numerous benefits, including muscular strength, flexibility, control, and core stability. Pilates has been widely utilized in the prevention and rehabilitation of a variety of musculoskeletal disorders. Objectives The aim of this study was to explore the experiences and opinions of Pilates trained NHS and private practice physiotherapists in the UK, regarding the perceived benefits, risks, delivery and rationale for this exercise method. Methods This qualitative study used a self‐designed electronic survey to retrieve the views of 30 physiotherapists, who had undertaken formal Pilates Instruction training, recruited by a purposive and snowball sampling method. Questions were either multiple choice or open‐ended, examined via thematic analysis. Results Physiotherapists identified the most important benefits of Pilates as reduction in fear‐avoidance, improving bodily awareness and increasing muscular strength. Exercises that promote general movement were highlighted as being particularly useful, with a majority recommending daily practice for optimum benefit. Participants recognized lack of core strength as a key indicator, whereas others criticized excessive focus on this principle. Conclusions Physiotherapists identified a range of inter‐linked benefits and recognized that Pilates is hugely modifiable. Individualizing exercises can further encourage participation and negate the restriction of some health conditions. NHS and Private Practice Therapists utilize Pilates in a similar way, although rationales for its use may differ, as the justification for Pilates exercise may be evolving. Pilates appears a valuable methodology in the NHS, which can help patients engage with activity

    A mixed methods evaluation of medical tattooing for people who have experienced a burn injury

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    Introduction: There are no existing studies examining the psychological merits of using facial medical tattooing (MT) following burn injury. This study evaluated an MT service supported by The Katie Piper Foundation. It examined accessibility, satisfaction and whether there were improvements in quality of life (QoL). Methods: Thirty-five service-users were invited to participate in a cross-sectional online survey. Twenty-five (71%) responded (24 women; age range = 21–64 years), and of these five (4 women; age range = 26–59 years) also participated in telephone interviews, which were analysed using descriptive thematic analysis. Findings: The service was largely considered easy to access (22/25) and convenient (25/25). Most service-users (22/25) were satisfied with the results of MT. Some areas of dissatisfaction were described, by a minority of service-users, including: the procedure being painful (1/25); the tattoo being below expectation or fading over time (3/25). The majority reported that MT had improved confidence (22/25); mood (19/25); and ability to socialise (19/25). The procedure improved some service-users’ ability to carry out essential activities (14/25) and enjoyable activities (16/25). The qualitative responses provided during interview, indicated that all respondents found the procedure useful to their adjustment, although a minority (3/5) found it painful and also commented on fading (1/5). All described MT as contributing to a sense of increased normality. Conclusions: MT had the largest impact on emotional wellbeing and interpersonal domains of QoL. MT services should now improve awareness of the procedure, lobby for further support to provide wider access to the procedure, and routinely use measures assessing psychosocial outcomes

    What difference does it make? Findings of an impact study of service user and carer involvement on social work students’ subsequent practice

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    This paper reports on a study which followed up a group of social work students to explore whether service user involvement in their education made any difference to their practice and whether there were different models or types of involvement which had a more significant impact than others. The findings showed that the impact was individual to each student. It was often specific encounters or ‘light bulb moments’ which led to increased awareness or insight into their own practice particularly when encountering similar situations or when pressures of practice led to them losing sight of service user perspectives. The paper shares these findings and considers the learning for educators in developing models of involvement which enhance impact on subsequent practice
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