618 research outputs found

    On the arithmetic of special values of LL-functions for certain abelian varieties with a rational isogeny

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    Let NN and pp be primes 5\geq 5 such that pN1p \mid \mid N-1. In this situation, Mazur defined and studied the pp-Eisenstein quotient J~(p)\tilde{J}^{(p)} of J0(N)J_0(N). We prove a kind of modulo pp version of the Birch and Swinnerton-Dyer conjecture for the ``pp-Eisenstein part'' of even quadratic twists of J~(p)\tilde{J}^{(p)}. Our result is the analogue for even quadratic twists of a result of Mazur concerning odd quadratic twists.Comment: New version with corrections of our previous preprin

    Explaining variation in GP referral rates for x-rays for back pain

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    BACKGROUND: Despite the availability of clinical guidelines for the management of low back pain (LBP), there continues to be wide variation in general practitioners' (GPs') referral rates for lumbar spine x-ray (LSX). This study aims to explain variation in GPs' referral rates for LSX from their accounts of the management of patients with low back pain. METHODS: Qualitative, semi-structured interviews with 29 GPs with high and low referral rates for LSX in North East England. Thematic analysis used constant comparative techniques. RESULTS: Common and divergent themes were identified among high- and low-users of LSX. Themes that were similar in both groups included an awareness of current guidelines for the use of LSX for patients with LBP and the pressure from patients and institutional factors to order a LSX. Differentiating themes for the high-user group included: a belief that LSX provides reassurance to patients that can outweigh risks, pessimism about the management options for LBP, and a belief that denying LSX would adversely affect doctor-patient relationships. Two specific differentiating themes are considered in more depth: GPs' awareness of their use of lumbar spine radiology relative to others, and the perceived risks associated with LSX radiation. CONCLUSION: Several key factors differentiate the accounts of GPs who have high and low rates of referral for LSX, even though they are aware of clinical guideline recommendations. Intervention studies that aim to increase adherence to guideline recommendations on the use of LSX by changing the ordering behaviour of practitioners in primary care should focus on these factors
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