1,896 research outputs found

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Prevalence of and characteristics associated with insomnia and obstructive sleep apnea among veterans with knee and hip osteoarthritis

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    Abstract Background Few studies have examined patterns of specific sleep problems among individuals with osteoarthritis (OA). The primary objective of this study was to examine prevalence of symptoms of insomnia and obstructive sleep apnea (OSA) among Veterans with OA. Secondary objectives were to assess proportions of individuals with insomnia and OSA symptoms who may have been undiagnosed and to examine Veterans’ characteristics associated with insomnia and OSA symptoms. Methods Veterans (n = 300) enrolled in a clinical trial completed the Insomnia Severity Index (ISI) and the Berlin Questionnaire (BQ) at baseline; proportions of participants with symptoms consistent with insomnia and OSA were calculated, using standard cut-offs for ISI and BQ. For Veterans with insomnia and OSA symptoms, electronic medical records were searched to identify whether there was a diagnosis code for these conditions. Multivariable linear (ISI) and logistic (BQ) regression models examined associations of the following characteristics with symptoms of insomnia and OSA: age, gender, race, self-reported general health, body mass index (BMI), diagnosis of post-traumatic stress disorder (PTSD), pain severity, depressive symptoms, number of joints with arthritis symptoms and opioid use. Results Symptoms consistent with insomnia and OSA were found in 53 and 66% of this sample, respectively. Among participants screening positive for insomnia and OSA, diagnosis codes for these disorders were present in the electronic medical record for 22 and 51%, respectively. Characteristics associated with insomnia were lower age (β (SE) = − 0.09 (0.04), 95% confidence interval [CI] = − 0.16, − 0.02), having a PTSD diagnosis (β (SE) = 1.68 (0.73), CI = 0.25, 3.11), greater pain severity (β (SE) = 0.36 (0.09), CI = 0.17, 0.55), and greater depressive symptoms (β (SE) = 0.84 (0.07), CI = 0.70, 0.98). Characteristics associated with OSA were higher BMI (odds ratio [OR] = 1.13, CI = 1.06, 1.21), greater depressive symptoms (OR = 1.12, CI = 1.05, 1.20), and opioid use (OR = 0.51, CI = 0.26, 0.99). Conclusions Insomnia and OSA symptoms were very common in Veterans with OA, and a substantial proportion of individuals with symptoms may have been undiagnosed. Characteristics associated with insomnia and OSA symptoms were consistent with prior studies. Trial registration NCT01130740
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