994 research outputs found

    Can the polarization of the strange quarks in the proton be positive ?

    Full text link
    Recently, the HERMES Collaboration at DESY, using a leading order QCD analysis of their data on semi-inclusive deep inelastic production of charged hadrons, reported a marginally positive polarization for the strange quarks in the proton. We argue that a non-negative polarization is almost impossible.Comment: 6 pages, latex, minor changes in the discussion after Eq. (9

    A Gravitational Aharonov-Bohm Effect, and its Connection to Parametric Oscillators and Gravitational Radiation

    Full text link
    A thought experiment is proposed to demonstrate the existence of a gravitational, vector Aharonov-Bohm effect. A connection is made between the gravitational, vector Aharonov-Bohm effect and the principle of local gauge invariance for nonrelativistic quantum matter interacting with weak gravitational fields. The compensating vector fields that are necessitated by this local gauge principle are shown to be incorporated by the DeWitt minimal coupling rule. The nonrelativistic Hamiltonian for weak, time-independent fields interacting with quantum matter is then extended to time-dependent fields, and applied to problem of the interaction of radiation with macroscopically coherent quantum systems, including the problem of gravitational radiation interacting with superconductors. But first we examine the interaction of EM radiation with superconductors in a parametric oscillator consisting of a superconducting wire placed at the center of a high Q superconducting cavity driven by pump microwaves. We find that the threshold for parametric oscillation for EM microwave generation is much lower for the separated configuration than the unseparated one, which then leads to an observable dynamical Casimir effect. We speculate that a separated parametric oscillator for generating coherent GR microwaves could also be built.Comment: 25 pages, 5 figures, YA80 conference (Chapman University, 2012

    Universally Coupled Massive Gravity, II: Densitized Tetrad and Cotetrad Theories

    Full text link
    Einstein's equations in a tetrad formulation are derived from a linear theory in flat spacetime with an asymmetric potential using free field gauge invariance, local Lorentz invariance and universal coupling. The gravitational potential can be either covariant or contravariant and of almost any density weight. These results are adapted to produce universally coupled massive variants of Einstein's equations, yielding two one-parameter families of distinct theories with spin 2 and spin 0. The theories derived, upon fixing the local Lorentz gauge freedom, are seen to be a subset of those found by Ogievetsky and Polubarinov some time ago using a spin limitation principle. In view of the stability question for massive gravities, the proven non-necessity of positive energy for stability in applied mathematics in some contexts is recalled. Massive tetrad gravities permit the mass of the spin 0 to be heavier than that of the spin 2, as well as lighter than or equal to it, and so provide phenomenological flexibility that might be of astrophysical or cosmological use.Comment: 2 figures. Forthcoming in General Relativity and Gravitatio

    Racial and ethnic differences in cervical cancer screening barriers and intentions: The My Body My Test-3 HPV self-collection trial among under-screened, low-income women

    Get PDF
    Under-screened women are more likely to be diagnosed with invasive cervical cancer at later stages and have worse survival outcomes. Under- or un-insured women, low-income women, and minoritized groups face barriers to screening. Intention to screen is an indicator of future screening behavior, yet is understudied among low-income, under-screened women. Participants were 710 low-income, uninsured or publicly insured women ages 25–64 years in North Carolina who were not up to date on cervical cancer screening according to national guidelines. Participants were asked about barriers to screening and intention to screen. We estimated reported barriers to cervical cancer screening stratified by race and ethnicity (categorized as White, Black, and Hispanic) and assessed predictors of intention to screen. Sixty-one percent of all participants reported 5 or more barriers to screening. The most commonly reported reasons for not getting screened were lack of insurance (White: 71%, Black: 62%, Hispanic/Latina: 63%) and cost (White: 55%, Black: 44%, Hispanic/ Latina: 61%). Women were more likely to have an intention to screen if they reported “it was not hard to get screening” (OR: 1.47 (1.00, 2.15)). Older women reported being less likely to intend to screen. Black women reported being more likely to intend to screen than White women. Lack of health insurance and cost were frequently reported barriers to cervical cancer screening. Increasing knowledge of affordable clinics and expanding access to Medicaid may reduce barriers and increase cervical cancer screening uptake

    SRAO CO Observation of 11 Supernova Remnants in l = 70 to 190 deg

    Full text link
    We present the results of 12CO J = 1-0 line observations of eleven Galactic supernova remnants (SNRs) obtained using the Seoul Radio Astronomy Observatory (SRAO) 6-m radio telescope. The observation was made as a part of the SRAO CO survey of SNRs between l = 70 and 190 deg, which is intended to identify SNRs interacting with molecular clouds. The mapping areas for the individual SNRs are determined to cover their full extent in the radio continuum. We used halfbeam grid spacing (60") for 9 SNRs and full-beam grid spacing (120") for the rest. We detected CO emission towards most of the remnants. In six SNRs, molecular clouds showed a good spatial relation with their radio morphology, although no direct evidence for the interaction was detected. Two SNRs are particularly interesting: G85.4+0.7, where there is a filamentary molecular cloud along the radio shell, and 3C434.1, where a large molecular cloud appears to block the western half of the remnant. We briefly summarize the results obtained for individual SNRs.Comment: Accepted for publication in Astrophysics & Space Science. 12 pages, 12 figures, and 3 table

    Perceived Financial Barriers to Cervical Cancer Screening and Associated Cost Burden among Low-Income, Under-Screened Women

    Get PDF
    Background: Despite screening's effectiveness in reducing cervical cancer incidence and mortality, disparities in cervical cancer screening uptake remain, with lower rates documented among uninsured and low-income individuals. We examined perceived financial barriers to, and the perceived cost burden of, cervical cancer screening. Materials and Methods: We surveyed 702 low-income, uninsured or publicly insured women ages 25-64 years in North Carolina, U.S., who were not up to date on cervical cancer screening according to national guidelines. Participants were asked about perceived financial barriers to screening and how much they perceived screening would cost. We used multivariable logistic regression to assess the sociodemographic predictors of perceived financial barriers. Results: Seventy-two percent of participants perceived financial barriers to screening. Screening appointment costs (71%) and follow-up/future treatment costs (44%) were most commonly reported, followed by lost pay due to time missed from work (6%) and transportation costs (5%). In multivariable analysis, being uninsured (vs. publicly insured), younger (25-34 vs. 50-64 years), White (vs. Black), and not reporting income data were associated with perceiving screening costs and future treatment costs as barriers to screening. Participants reported wide-ranging estimates of the perceived out-of-pocket cost of screening (00-1300), with a median expected cost of $245. Conclusions: The majority of our sample of low-income women perceived substantial financial barriers to screening, particularly related to screening appointment costs and potential follow-up/future treatment costs. Providing greater cost transparency and access to financial assistance may reduce perceived financial barriers to screening, potentially increasing screening uptake among this underserved population. Clinicaltrials.gov registration number NCT02651883

    Differential cross sections, charge production asymmetry, and spin-density matrix elements for D*(2010) produced in 500 GeV/c pi^- nucleon interactions

    Full text link
    We report differential cross sections for the production of D*(2010) produced in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also report the D* +/- charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are \eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles, respectively.Comment: LaTeX2e (elsart.cls). 13 pages, 6 figures (eps files). Submitted to Physics Letters

    Brane Inflation, Solitons and Cosmological Solutions: I

    Full text link
    In this paper we study various cosmological solutions for a D3/D7 system directly from M-theory with fluxes and M2-branes. In M-theory, these solutions exist only if we incorporate higher derivative corrections from the curvatures as well as G-fluxes. We take these corrections into account and study a number of toy cosmologies, including one with a novel background for the D3/D7 system whose supergravity solution can be completely determined. This new background preserves all the good properties of the original model and opens up avenues to investigate cosmological effects from wrapped branes and brane-antibrane annihilation, to name a few. We also discuss in some detail semilocal defects with higher global symmetries, for example exceptional ones, that could occur in a slightly different regime of our D3/D7 model. We show that the D3/D7 system does have the required ingredients to realise these configurations as non-topological solitons of the theory. These constructions also allow us to give a physical meaning to the existence of certain underlying homogeneous quaternionic Kahler manifolds.Comment: Harvmac, 115 pages, 9 .eps figures; v2: typos corrected, references added and the last section expanded; v3: Few minor typos corrected and references added. Final version to appear in JHE

    Patterns and Predictors of Oral Anticancer Agent Use in Diverse Patients with Metastatic Renal Cell Carcinoma

    Get PDF
    PURPOSE Availability of targeted oral anticancer agents (OAAs) has transformed care for patients with metastatic renal cell carcinoma (mRCC). Our objective was to identify patterns and predictors of OAA use within 12 months after mRCC was detected to understand real-world adoption of OAAs. METHODS We used a novel, North Carolina cancer registry–linked multipayer claims data resource to examine patterns of use of five oral therapies among patients with mRCC diagnosed in 2006-2015, with claims through 2016. Patients were required to have 12 months of continuous enrollment before metastatic index date. Log-Poisson models estimated unadjusted and adjusted risk ratios (RRs) for associations between patient characteristics and OAA use. In sensitivity analyses, we used a competing risk framework to estimate adjusted risk differences in OAA use. RESULTS Our population-based study of 713 patients demonstrated low (37%) OAA use during the first year after metastatic index date among both publicly and privately insured patients, with shifting patterns of use consistent with regulatory approvals over time. Compared with patients age 18-49 years, patients age 70-74 years were half likely to use OAAs (95% confidence limit [CL], 0.34 to 0.78) and patients age 801 years were 71% less likely to use OAAs (95% CL, 0.17 to 0.50). Patients with two comorbidities (RR, 0.73; 95% CL, 0.55 to 0.98) and those with 31 comorbidities (RR, 0.68; 95% CL, 0.50 to 0.91) were less likely to receive OAA than those without comorbidities. Patients with higher frailty also had lower OAA utilization (RR, 0.67; 95% CL, 0.52 to 0.85). CONCLUSION These findings suggest a need to better understand the system-level and provider-level drivers of OAA underuse, as well as OAA adherence and associated survival

    Provider- and patient-level predictors of oral anticancer agent initiation and adherence in patients with metastatic renal cell carcinoma

    Get PDF
    Background: Improving oral anticancer agent (OAA) initiation and adherence is the important quality-of-care issues, particularly since one fourth of anticancer agents being developed will be administered orally. Our objective was to identify provider- and patient-level characteristics associated with OAA initiation and adherence among individuals with metastatic renal cell carcinoma (mRCC). Methods: We used state cancer registry data linked to multi-payer claims data to identify patients with mRCC diagnosed in 2004–2015. Provider data were obtained from North Carolina Health Professions Data System and the National Plan & Provider Enumeration System. We estimated risk ratios (RRs) and corresponding 95% confidence limits (CLs) using modified Poisson regression to evaluate factors associated with OAA initiation and adherence. Results: Among the 207 (out of 687) patients who initiated an OAA following mRCC diagnosis and survived 90 days, median proportion of days covered was 0.91. Patients with a modal provider specializing in hematology/medical oncology were much more likely to initiate OAAs than those seen by other specialties. Additionally, patients with a female provider were more likely to initiate OAAs than those with a male provider. Compared to patients treated by providers practicing in both urban and rural areas, patients with providers practicing solely in urban areas were more likely to initiate OAAs, after controlling for patient-level factors (RR = 1.37; 95% CL: 1.09–1.73). Medicare patients were less likely to be adherent than those with private insurance (RR = 0.61; 95% CL: 0.42–0.87). Conclusions: Our results suggest that provider- and patient-level factors influence OAA initiation in patients with mRCC but only insurance type was associated with adherence
    corecore