21 research outputs found

    Continuous Gravitational Waves from Isolated Galactic Neutron Stars in the Advanced Detector Era

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    We consider a simulated population of isolated Galactic neutron stars. The rotational frequency of each neutron star evolves through a combination of electromagnetic and gravitational wave emission. The magnetic field strength dictates the dipolar emission, and the ellipticity (a measure of a neutron star's deformation) dictates the gravitational wave emission. Through both analytic and numerical means, we assess the detectability of the Galactic neutron star population and bound the magnetic field strength and ellipticity parameter space of Galactic neutron stars with or without a direct gravitational wave detection. While our simulated population is primitive, this work establishes a framework by which future efforts can be conducted.Comment: Accepted for publication by Physical Review D, 8 pages, 5 figure

    Arecibo PALFA Survey and Einstein@Home: Binary Pulsar Discovery by Volunteer Computing

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    We report the discovery of the 20.7 ms binary pulsar J1952+2630, made using the distributed computing project Einstein@Home in Pulsar ALFA survey observations with the Arecibo telescope. Follow-up observations with the Arecibo telescope confirm the binary nature of the system. We obtain a circular orbital solution with an orbital period of 9.4 hr, a projected orbital radius of 2.8 lt-s, and a mass function of f = 0.15 M ☉ by analysis of spin period measurements. No evidence of orbital eccentricity is apparent; we set a 2σ upper limit e 1.7 × 10–3. The orbital parameters suggest a massive white dwarf companion with a minimum mass of 0.95 M ☉, assuming a pulsar mass of 1.4 M ☉. Most likely, this pulsar belongs to the rare class of intermediate-mass binary pulsars. Future timing observations will aim to determine the parameters of this system further, measure relativistic effects, and elucidate the nature of the companion star

    The Einstein@Home Search for Radio Pulsars and PSR J2007+2722

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    Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 193 countries, to search for new neutron stars using data from electromagnetic and gravitational-wave detectors. This paper presents a detailed description of the search for new radio pulsars using Pulsar ALFA survey data from the Arecibo Observatory. The enormous computing power allows this search to cover a new region of parameter space; it can detect pulsars in binary systems with orbital periods as short as 11 minutes. We also describe the first Einstein@Home discovery, the 40.8 Hz isolated pulsar PSR J2007+2722, and provide a full timing model. PSR J2007+2722\u27s pulse profile is remarkably wide with emission over almost the entire spin period. This neutron star is most likely a disrupted recycled pulsar, about as old as its characteristic spin-down age of 404 Myr. However, there is a small chance that it was born recently, with a low magnetic field. If so, upper limits on the X-ray flux suggest but cannot prove that PSR J2007+2722 is at least ~100 kyr old. In the future, we expect that the massive computing power provided by volunteers should enable many additional radio pulsar discoveries

    Unmet Need for Social and Emotional Support and Lack of Recalled Screening Is Associated with Depression in the Long-Term Course After Stroke.

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    PURPOSE: Details on adequate care and prevalence of depression in long-term stroke aftercare are limited. We aimed to determine long-term depression rates after stroke and to test for an association between depression and inadequate screening, socio-economic complications and lack of sub-optimal care. PATIENTS AND METHODS: In this cross-sectional study, 57 patients were re-invited into the clinic 2-3 years after stroke. Patients were interviewed about recalled screening concerning depression and unmet needs. Depression, the patient's social situation, and confounders were assessed by standardized scores. RESULTS: In our study, 20% (n = 11) of patients were classified as depressed by the HDRS-17 score result. However, only 36% of all patients recalled to have been previously screened for depression and only 43% of those patients also recalled out-patient screening. Patients classified as depressed reported significantly lower recalled screening rates (9% vs 43%; p = 0.036) and higher rates of self-reported unmet need with emotional problems (72% vs 18%; p < 0.001). Depression in our study was further associated with a worse socio-economic situation, fewer social contacts, unmet needs with regard to emotional problems and higher rates of recommendations to apply for additional social support. CONCLUSION: Our data suggest that systematic out-patient screening for depression is lacking in stroke aftercare. Furthermore, the high rate of unmet emotional needs, the poor socio-economic situation and the higher rates of recommendations for social counselling and application for benefits suggest an undersupply of care in the out-patient setting that is more prominent in patients with depression and warrants further studies to investigate the underlying causes

    Social work support and unmet social needs in life after stroke: a cross-sectional exploratory study

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    Background: Stroke patients are often affected by long-term disabilities with needs concerning social issues. There is relatively little consideration of social recovery of patients and the support required to return to work, receive social benefits, participate in daily life activities, maintain contact with family and friends and to organize financial affairs. In our study we aimed to investigate if existing tools record social needs adequately. We analyzed the current provision of social support provided in long-term care after stroke and whether unmet social needs were associated with quality of life, caregiver burden, overall function and degree of disability. Methods: Our analysis is part of the Managing Aftercare of Stroke study (MAS-I), a cross-sectional exploratory study of patient needs 2–3 years after initial stroke. Assessment tools included the Nikolaus-score (social situation), the EuroQoL (quality of life), the German Burden Scale for Family Caregivers (caregiver burden), the modified Rankin Scale (disability / dependence), Stroke Impact Scale (function and degree of disability) and the Stroke Survivor Needs Questionnaire (unmet needs). Results: Overall 57 patients were included in MAS-I, with ten patients classified in urgent need of socio-economic support according to the Nikolaus-score. Patients with lower than normal Nikolaus-score had a higher degree of disability. Thirty percent of all patients had never received professional social support. Social worker contact happened mostly during the stay in acute hospital or rehabilitation institution. Only four patients (11%) reported long-term support after discharge. Apart from social worker contact during acute care, 43% of patients had unmet needs in the long-term aftercare. Forty percent of all patients included in MAS-I were recommended for social work intervention after an in-depth analysis of their situation. Finally, we saw that unmet social needs were associated with lower quality of life and higher caregiver burden. Conclusions: Our data suggest significant unmet needs in social care in long-term stroke patients. Screening tools for unmet social needs such as the Nikolaus-score do not holistically report patients’ needs

    Pulsar Discovery by Global Volunteer Computing

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    Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 192 countries to mine large data sets. It has now found a 40.8-hertz isolated pulsar in radio survey data from the Arecibo Observatory taken in February 2007. Additional timing observations indicate that this pulsar is likely a disrupted recycled pulsar. PSR J2007+2722’s pulse profile is remarkably wide with emission over almost the entire spin period; the pulsar likely has closely aligned magnetic and spin axes. The massive computing power provided by volunteers should enable many more such discoveries
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