222 research outputs found

    A characterization of two weight norm inequality for Littlewood-Paley gλ∗g_{\lambda}^{*}-function

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    Let n≥2n\ge 2 and gλ∗g_{\lambda}^{*} be the well-known high dimensional Littlewood-Paley function which was defined and studied by E. M. Stein, \begin{align*} g_{\lambda}^{*}(f)(x) =\bigg(\iint_{\mathbb R^{n+1}_{+}} \Big(\frac{t}{t+|x-y|}\Big)^{n\lambda} |\nabla P_tf(y,t)|^2 \frac{dy dt}{t^{n-1}}\bigg)^{1/2}, \ \quad \lambda > 1, \end{align*} where Ptf(y,t)=pt∗f(y)P_tf(y,t)=p_t*f(y), pt(y)=t−np(y/t)p_t(y)=t^{-n}p(y/t) and p(x)=(1+∣x∣2)−(n+1)/2p(x) = (1+|x|^2)^{-(n+1)/2}, ∇=(∂∂y1,…,∂∂yn,∂∂t)\nabla =(\frac{\partial}{\partial y_1},\ldots,\frac{\partial}{\partial y_n},\frac{\partial}{\partial t}). In this paper, we give a characterization of two-weight norm inequality for gλ∗g_{\lambda}^{*}-function. We show that, ∥gλ∗(fσ)∥L2(w)≲∥f∥L2(σ)\big\| g_{\lambda}^{*}(f \sigma) \big\|_{L^2(w)} \lesssim \big\| f \big\|_{L^2(\sigma)} if and only if the two-weight Muchenhoupt A2A_2 condition holds, and a testing condition holds : \begin{align*} \sup_{Q : cubes \ in \mathbb R^n} \frac{1}{\sigma(Q)} \int_{\mathbb R^n} \iint_{\widehat{Q}} \Big(\frac{t}{t+|x-y|}\Big)^{n\lambda}|\nabla P_t(\mathbf{1}_Q \sigma)(y,t)|^2 \frac{w dx dt}{t^{n-1}} dy < \infty, \end{align*} where Q^\widehat{Q} is the Carleson box over QQ and (w,σ)(w, \sigma) is a pair of weights. We actually prove this characterization for gλ∗g_{\lambda}^{*}-function associated with more general fractional Poisson kernel pα(x)=(1+∣x∣2)−(n+α)/2p^\alpha(x) = (1+|x|^2)^{-{(n+\alpha)}/{2}}. Moreover, the corresponding results for intrinsic gλ∗g_{\lambda}^*-function are also presented.Comment: 21 pages, to appear in Journal of Geometric Analysi

    Comparison of the efficacy of half ticagrelor loading doses and clopidogrel in elderly acute coronary syndrome patients in China

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    Purpose: To evaluate the effects of half-load doses (HLD) of ticagrelor and clopidogrel on elderly acute coronary syndrome patients (ACS) over a period of 90 days. Methods: Seventy-four patients diagnosed as ACS were included in this trial. The patients were randomly distributed into group 1 (treated with HLD ticagrelor, 90 mg LD) and group 2 (treated with clopidogrel, 300 mg LD). The interaction of treatment effect was evaluated using Multivariate Cox proportional hazards regression models. Results: Within three months, a total of 12 patients (16.21 %) died of myocardial infarction or stroke. The endpoint of HLD ticagrelor-treated elderly ACS patients was 20 %, and the incidence of clopidogreltreated endpoints was 14.81 %. Conclusion: In the first 45 patients treated with HLD ticagrelor, their cumulative incidence of cardiac events was relatively high. However, there were no considerable changes in the therapeutic benefits of these two drugs in elderly ACS patients. Keywords: Elder patients, Acute coronary syndrome, Ticagrelor, Clopidogre
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