1,970 research outputs found

    A millisecond pulsar in a stellar triple system

    Full text link
    Gravitationally bound three-body systems have been studied for hundreds of years and are common in our Galaxy. They show complex orbital interactions, which can constrain the compositions, masses, and interior structures of the bodies and test theories of gravity, if sufficiently precise measurements are available. A triple system containing a radio pulsar could provide such measurements, but the only previously known such system, B1620-26 (with a millisecond pulsar, a white dwarf, and a planetary-mass object in an orbit of several decades), shows only weak interactions. Here we report precision timing and multi-wavelength observations of PSR J0337+1715, a millisecond pulsar in a hierarchical triple system with two other stars. Strong gravitational interactions are apparent and provide the masses of the pulsar (1.4378(13) Msun, where Msun is the solar mass and the parentheses contain the uncertainty in the final decimal places) and the two white dwarf companions (0.19751(15) Msun and 0.4101(3) Msun), as well as the inclinations of the orbits (both approximately 39.2 degrees). The unexpectedly coplanar and nearly circular orbits indicate a complex and exotic evolutionary past that differs from those of known stellar systems. The gravitational field of the outer white dwarf strongly accelerates the inner binary containing the neutron star, and the system will thus provide an ideal laboratory in which to test the strong equivalence principle of general relativity.Comment: 17 pages, 3 figures, 1 table. Published online by Nature on 5 Jan 2014. Extremely minor differences with published version may exis

    Too Much of a Good Thing? Overexertion of Self-Control and Dietary Adherence in Individuals with Type 2 Diabetes

    Get PDF
    Objectives The resource model of self‐control posits that self‐control is a finite resource that can be depleted. Individuals with diabetes must continually restrict their diet, requiring self‐control. As a result, dietary adherence is difficult, and lapses are common. People with diabetes who overexert self‐control following a lapse may be especially likely to experience a subsequent relapse, as suggested by the resource model. This investigation used the resource model of self‐control to test whether overexertion of dietary self‐control following a lapse would be predictive of a subsequent relapse in dietary control. Design We tested this prediction in a daily diary study of 128 individuals with diabetes (Mage = 66.12). Methods Participants\u27 reports of their daily dietary adherence were used to define lapses in adherence, post‐lapse adherence, and relapses. Results Individuals who overexerted self‐control after a lapse were more likely to experience a subsequent relapse (OR = 3.276, p = .016) and to do so sooner (HR = 2.12, p = .023). Conclusions People with diabetes may seek to compensate for a lapse in adherence by overexerting self‐control, but doing so may deplete their self‐control and increase the risk of a future relapse

    Primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphomas: reappraisal of a provisional entity in the 2016 WHO classification of cutaneous lymphomas.

    Get PDF
    Primary cutaneous CD8-positive aggressive epidermotropic T-cell lymphoma is a rare and poorly characterized variant of cutaneous lymphoma still considered a provisional entity in the latest 2016 World Health Organization Classification of Cutaneous lymphomas. We sought to better characterize and provide diagnostic and therapeutic guidance of this rare cutaneous lymphoma. Thirty-four patients with a median age of 77 years (range 19-89 years) presented primarily with extensive annular necrotic plaques or tumor lesions with frequent mucous membrane involvement. The 5-year survival was 32% with a median survival of 12 months. A subset of 17 patients had a prodrome of chronic patches prior to the development of aggressive ulcerative lesions. We identified cases with lack of CD8 or αÎČ T-cell receptor expression yet with similar clinical and pathological presentation. Allogeneic stem cell transplantation provided partial or complete remissions in 5/6 patients. We recommend the term primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphoma as this more broad designation better describes this clinical-pathologic presentation, which allows the inclusion of cases with CD8 negative and/or αÎČ/γΎ T-cell receptor chain double-positive or double-negative expression. We have identified early skin signs of chronic patch/plaque lesions that are often misdiagnosed as eczema, psoriasis, or mycosis fungoides. Our experience confirms the poor prognosis of this entity and highlights the inefficacy of our standard therapies with the exception of allogeneic stem cell transplantation in selected cases

    A 450 million years long latitudinal gradient in age-dependent extinction.

    Get PDF
    Leigh Van Valen famously stated that under constant conditions extinction probability is independent of species age. To test this 'law of constant extinction', we developed a new method using deep learning to infer age-dependent extinction and analysed 450 myr of marine life across 21 invertebrate clades. We show that extinction rate significantly decreases with age in > 90% of the cases, indicating that most species died out soon after their appearance while those which survived experienced ever decreasing extinction risk. This age-dependent extinction pattern is stronger towards the Equator and holds true when the potential effects of mass extinctions and taxonomic inflation are accounted for. These results suggest that the effect of biological interactions on age-dependent extinction rate is more intense towards the tropics. We propose that the latitudinal diversity gradient and selection at the species level account for this exceptional, yet little recognised, macroevolutionary and macroecological pattern

    A 450 million years long latitudinal gradient in age-dependent extinction

    Get PDF
    Leigh Van Valen famously stated that under constant conditions extinction probability is independent of species age. To test this 'law of constant extinction', we developed a new method using deep learning to infer age-dependent extinction and analysed 450 myr of marine life across 21 invertebrate clades. We show that extinction rate significantly decreases with age in > 90% of the cases, indicating that most species died out soon after their appearance while those which survived experienced ever decreasing extinction risk. This age-dependent extinction pattern is stronger towards the Equator and holds true when the potential effects of mass extinctions and taxonomic inflation are accounted for. These results suggest that the effect of biological interactions on age-dependent extinction rate is more intense towards the tropics. We propose that the latitudinal diversity gradient and selection at the species level account for this exceptional, yet little recognised, macroevolutionary and macroecological pattern

    The seasonality of tuberculosis, sunlight, vitamin D, and household crowding.

    Get PDF
    BACKGROUND: Unlike other respiratory infections, tuberculosis diagnoses increase in summer. We performed an ecological analysis of this paradoxical seasonality in a Peruvian shantytown over 4 years. METHODS: Tuberculosis symptom-onset and diagnosis dates were recorded for 852 patients. Their tuberculosis-exposed cohabitants were tested for tuberculosis infection with the tuberculin skin test (n = 1389) and QuantiFERON assay (n = 576) and vitamin D concentrations (n = 195) quantified from randomly selected cohabitants. Crowding was calculated for all tuberculosis-affected households and daily sunlight records obtained. RESULTS: Fifty-seven percent of vitamin D measurements revealed deficiency (<50 nmol/L). Risk of deficiency was increased 2.0-fold by female sex (P < .001) and 1.4-fold by winter (P < .05). During the weeks following peak crowding and trough sunlight, there was a midwinter peak in vitamin D deficiency (P < .02). Peak vitamin D deficiency was followed 6 weeks later by a late-winter peak in tuberculin skin test positivity and 12 weeks after that by an early-summer peak in QuantiFERON positivity (both P < .04). Twelve weeks after peak QuantiFERON positivity, there was a midsummer peak in tuberculosis symptom onset (P < .05) followed after 3 weeks by a late-summer peak in tuberculosis diagnoses (P < .001). CONCLUSIONS: The intervals from midwinter peak crowding and trough sunlight to sequential peaks in vitamin D deficiency, tuberculosis infection, symptom onset, and diagnosis may explain the enigmatic late-summer peak in tuberculosis

    Study of the reaction pbar p -> phi phi from 1.1 to 2.0 GeV/c

    Get PDF
    A study has been performed of the reaction pbar p -> 4K using in-flight antiprotons from 1.1 to 2.0 GeV/c incident momentum interacting with a hydrogen jet target. The reaction is dominated by the production of a pair of phi mesons. The pbar p -> phi phi cross section rises sharply above threshold and then falls continuously as a function of increasing antiproton momentum. The overall magnitude of the cross section exceeds expectations from a simple application of the OZI rule by two orders of magnitude. In a fine scan around the xi/f_J(2230) resonance, no structure is observed. A limit is set for the double branching ratio B(xi -> pbar p) * B(xi -> phi phi) < 6e-5 for a spin 2 resonance of M = 2.235 GeV and Width = 15 MeV.Comment: 13 pages, 13 figures, 2 tables, Latex. To be published in Phys. Rev.

    Trust not in money: The effect of financial conflict of interest disclosure on dietary behavioural intention

    Get PDF
    Purpose To determine the impact of financial conflict of interest (FCI) disclosure on dietary behavioural intention related to the glycaemic index (GI) of food. Design/methodology/approach Seventy-two participants were randomly allocated to two conditions by reading an academic journal article about GI that contained an FCI disclosure (conflict) or a statement detailing that the authors had no FCI to declare (no-conflict). Using a questionnaire, participants made judgments about the article and authors as well as intention to perform GI-related behaviour. These were then analysed for significant differences between the two conditions. Findings Although no significant differences emerged between group means of judgments about the article, those in the conflict condition judged the authors as significantly less trustworthy and credible than those in the conflict condition. Contrary to expectation, those in the conflict condition reported significantly higher intentions to perform GI-related behaviour. Research limitations/implications The present research must be conducted in other populations of interest in order to establish if the results can be generalised. Practical implications The results suggest that FCI disclosure might be best placed at the beginning of articles and that education about FCI be made available to the general public. Originality/value This paper examines the practical implications of FCI disclosure. It also focuses on a readership beyond an academic community who is well-acquainted with the subject area and issues pertaining to FCI
    • 

    corecore