320 research outputs found

    Weak in Space, Log in Time Improvement of the Lady{\v{z}}enskaja-Prodi-Serrin Criteria

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    In this article we present a Lady{\v{z}}enskaja-Prodi-Serrin Criteria for regularity of solutions for the Navier-Stokes equation in three dimensions which incorporates weak LpL^p norms in the space variables and log improvement in the time variable.Comment: 14 pages, to appea

    The Beale-Kato-Majda criterion to the 3D Magneto-hydrodynamics equations

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    We study the blow-up criterion of smooth solutions to the 3D MHD equations. By means of the Littlewood-Paley decomposition, we prove a Beale-Kato-Majda type blow-up criterion of smooth solutions via the vorticity of velocity only, i. e. \sup_{j\in\Z}\int_0^T\|\Delta_j(\na\times u)\|_\infty dt, where Δj\Delta_j is a frequency localization on ξ2j|\xi|\approx 2^j.Comment: 12page

    Interior regularity criteria for suitable weak solutions of the Navier-Stokes equations

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    We present new interior regularity criteria for suitable weak solutions of the 3-D Navier-Stokes equations: a suitable weak solution is regular near an interior point zz if either the scaled Lx,tp,qL^{p,q}_{x,t}-norm of the velocity with 3/p+2/q23/p+2/q\leq 2, 1q1\leq q\leq \infty, or the Lx,tp,qL^{p,q}_{x,t}-norm of the vorticity with 3/p+2/q33/p+2/q\leq 3, 1q<1 \leq q < \infty, or the Lx,tp,qL^{p,q}_{x,t}-norm of the gradient of the vorticity with 3/p+2/q43/p+2/q\leq 4, 1q1 \leq q, 1p1 \leq p, is sufficiently small near zz

    Conditional regularity of solutions of the three dimensional Navier-Stokes equations and implications for intermittency

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    Two unusual time-integral conditional regularity results are presented for the three-dimensional Navier-Stokes equations. The ideas are based on L2mL^{2m}-norms of the vorticity, denoted by Ωm(t)\Omega_{m}(t), and particularly on Dm=ΩmαmD_{m} = \Omega_{m}^{\alpha_{m}}, where αm=2m/(4m3)\alpha_{m} = 2m/(4m-3) for m1m\geq 1. The first result, more appropriate for the unforced case, can be stated simply : if there exists an 1m<1\leq m < \infty for which the integral condition is satisfied (Zm=Dm+1/DmZ_{m}=D_{m+1}/D_{m}) 0tln(1+Zmc4,m)dτ0 \int_{0}^{t}\ln (\frac{1 + Z_{m}}{c_{4,m}}) d\tau \geq 0 then no singularity can occur on [0,t][0, t]. The constant c4,m2c_{4,m} \searrow 2 for large mm. Secondly, for the forced case, by imposing a critical \textit{lower} bound on 0tDmdτ\int_{0}^{t}D_{m} d\tau, no singularity can occur in Dm(t)D_{m}(t) for \textit{large} initial data. Movement across this critical lower bound shows how solutions can behave intermittently, in analogy with a relaxation oscillator. Potential singularities that drive 0tDmdτ\int_{0}^{t}D_{m} d\tau over this critical value can be ruled out whereas other types cannot.Comment: A frequency was missing in the definition of D_{m} in (I5) v3. 11 pages, 1 figur

    Generalised Gagliardo–Nirenberg inequalities using weak Lebesgue spaces and BMO

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    Using elementary arguments based on the Fourier transform we prove that for 1qn(1/21/p)1 \leq q n(1/2-1/p), if fLq,(Rn)H˙s(Rn)f \in L^{q,\infty}(\R^n) \cap \dot{H}^s(\R^n) then fLp(Rn)f \in L^p(\R^n) and there exists a constant cp,q,sc_{p,q,s} such that fLpcp,q,sfLq,θfH˙s1θ, \|f\|_{L^p} \leq c_{p,q,s} \|f\|_{L^{q,\infty}}^\theta \|f\|_{\dot H^s}^{1-\theta}, where 1/p=θ/q+(1θ)(1/2s/n)1/p = \theta/q + (1-\theta)(1/2-s/n). In particular, in R2\R^2 we obtain the generalised Ladyzhenskaya inequality fL4cfL2,1/2fH˙11/2\|f\|_{L^4}\le c\|f\|_{L^{2,\infty}}^{1/2}\|f\|_{\dot H^1}^{1/2}. We also show that for s=n/2s=n/2 the norm in fH˙n/2\|f\|_{\dot H^{n/2}} can be replaced by the norm in BMO. As well as giving relatively simple proofs of these inequalities, this paper provides a brief primer of some basic concepts in harmonic analysis, including weak spaces, the Fourier transform, the Lebesgue Differentiation Theorem, and Calderon-Zygmund decompositions

    Alliance Foundation Trial 09: A randomized, multicenter, phase 2 trial evaluating two sequences of pembrolizumab and standard platinum-based chemotherapy in patients with metastatic NSCLC

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    INTRODUCTION: The sequence of chemotherapy and pembrolizumab may affect antitumor immune response and efficacy of immunotherapy. METHODS: This multicenter, randomized, phase 2 trial was designed to evaluate the efficacy of two sequences of chemotherapy and pembrolizumab in patients with stage 4 NSCLC. Both arms were considered investigational, and the study used a pick a winner design. The primary end point was objective response rate by independent radiologic review after eight cycles (24 wk). Patients were randomized 1:1 to arm A (chemotherapy for four cycles followed by pembrolizumab for four cycles) or arm B (pembrolizumab for four cycles followed by chemotherapy for four cycles). Patients in both arms without disease progression after the initial eight cycles continued pembrolizumab until disease progression, unacceptable toxicity, or a maximum of 2 years. RESULTS: From March 2016 to July 2018, a total of 90 eligible patients were randomized (43 patients to arm A and 47 patients to arm B). The objective response rate at 24 weeks in arms A and B was 39.5 % (95 % confidence interval [CI]: 24.9%-54.1 %) and 40.4 % (95 % CI: 26.4%-54.5 %), respectively ( CONCLUSIONS: Additional evaluation of either sequence in a phase 3 trial is not warranted

    On the regularity criterion of weak solution for the 3D viscous Magneto-hydrodynamics equations

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    We improve and extend some known regularity criterion of weak solution for the 3D viscous Magneto-hydrodynamics equations by means of the Fourier localization technique and Bony's para-product decomposition.Comment: 13page
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