687 research outputs found

    Biased statistics for traces of cyclic p-fold covers over finite fields

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    In this paper, we discuss in more detail some of the results on the statistics of the trace of the Frobenius endomorphism associated to cyclic p-fold covers of the projective line that were presented in [1]. We also show new findings regarding statistics associated to such curves where we fix the number of zeros in some of the factors of the equation in the affine model

    On the minimization of Dirichlet eigenvalues of the Laplace operator

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    We study the variational problem \inf \{\lambda_k(\Omega): \Omega\ \textup{open in}\ \R^m,\ |\Omega| < \infty, \ \h(\partial \Omega) \le 1 \}, where λk(Ω)\lambda_k(\Omega) is the kk'th eigenvalue of the Dirichlet Laplacian acting in L2(Ω)L^2(\Omega), \h(\partial \Omega) is the (m−1)(m-1)- dimensional Hausdorff measure of the boundary of Ω\Omega, and ∣Ω∣|\Omega| is the Lebesgue measure of Ω\Omega. If m=2m=2, and k=2,3,⋯k=2,3, \cdots, then there exists a convex minimiser Ω2,k\Omega_{2,k}. If m≄2m \ge 2, and if Ωm,k\Omega_{m,k} is a minimiser, then Ωm,k∗:=int(Ωm,k‟)\Omega_{m,k}^*:= \textup{int}(\overline{\Omega_{m,k}}) is also a minimiser, and Rm∖Ωm,k∗\R^m\setminus \Omega_{m,k}^* is connected. Upper bounds are obtained for the number of components of Ωm,k\Omega_{m,k}. It is shown that if m≄3m\ge 3, and k≀m+1k\le m+1 then Ωm,k\Omega_{m,k} has at most 44 components. Furthermore Ωm,k\Omega_{m,k} is connected in the following cases : (i) m≄2,k=2,m\ge 2, k=2, (ii) m=3,4,5,m=3,4,5, and k=3,4,k=3,4, (iii) m=4,5,m=4,5, and k=5,k=5, (iv) m=5m=5 and k=6k=6. Finally, upper bounds on the number of components are obtained for minimisers for other constraints such as the Lebesgue measure and the torsional rigidity.Comment: 16 page

    Traces, high powers and one level density for families of curves over finite fields

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    Optimization problems involving the first Dirichlet eigenvalue and the torsional rigidity

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    We present some open problems and obtain some partial results for spectral optimization problems involving measure, torsional rigidity and first Dirichlet eigenvalue.Comment: 18 pages, 4 figure

    Some remarks on the isoperimetric problem for the higher eigenvalues of the Robin and Wentzell Laplacians

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    We consider the problem of minimising the kkth eigenvalue, k≄2k \geq 2, of the (pp-)Laplacian with Robin boundary conditions with respect to all domains in RN\mathbb{R}^N of given volume MM. When k=2k=2, we prove that the second eigenvalue of the pp-Laplacian is minimised by the domain consisting of the disjoint union of two balls of equal volume, and that this is the unique domain with this property. For p=2p=2 and k≄3k \geq 3, we prove that in many cases a minimiser cannot be independent of the value of the constant α\alpha in the boundary condition, or equivalently of the volume MM. We obtain similar results for the Laplacian with generalised Wentzell boundary conditions Δu+ÎČ∂u∂Μ+Îłu=0\Delta u + \beta \frac{\partial u}{\partial \nu} + \gamma u = 0.Comment: 16 page

    KillerFLIP: A Novel Lytic Peptide Specifically Inducing Cancer Cell Death

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    One of the objectives in the development of effective cancer therapy is induction of tumor-selective cell death. Toward this end, we have identified a small peptide that, when introduced into cells via a TAT cell-delivery system, shows a remarkably potent cytoxicity in a variety of cancer cell lines and inhibits tumor growth in vivo, whereas sparing normal cells and tissues. This fusion peptide was named killer FLIP as its sequence was derived from the C-terminal domain of c-FLIP, an anti-apoptotic protein. Using structure activity analysis, we determined the minimal bioactive core of killerFLIP, namely killerFLIP-E. Structural analysis of cells using electron microscopy demonstrated that killerFLIP-E triggers cell death accompanied by rapid (within minutes) plasma membrane permeabilization. Studies of the structure of the active core of killer FLIP (-E) indicated that it possesses amphiphilic properties and self-assembles into micellar structures in aqueous solution. The biochemical properties of killerFLIP are comparable to those of cationic lytic peptides, which participate in defense against pathogens and have also demonstrated anticancer properties. We show that the pro-cell death effects of killer FLIP are independent of its sequence similarity with c-FLIP L as killer FLIP-induced cell death was largely apoptosis and necroptosis independent. A killer FLIP-E variant containing a scrambled c-FLIP L motif indeed induced similar cell death, suggesting the importance of the c-FLIP L residues but not of their sequence. Thus, we report the discovery of a promising synthetic peptide with novel anticancer activity in vitro and in vivo.

    SENSOR ARRAY ABLE TO DETECT AND RECOGNISE CHEMICAL WARFARE AGENTS

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    In this paper we studied a device based on array of six different sensors with surface acoustic wave for detections and recognition of three chemical warfare agents (chloropicrin, soman and lewisite). The sensors are “delay line” type with a center frequency of 69.4 MHz. It presents an original algorithm to identify the nature and concentration of gas from a finite range of possible gases. Numerical program developed to implement this algorithm, provides to operators all the particulars of gas and an indicator of credibility of the results provided as a measure of the degree of disturbance of the signals received from sensors.SAW, chemical warfare agent, array of sensors, algorithm

    eXamine: a Cytoscape app for exploring annotated modules in networks

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    Background. Biological networks have growing importance for the interpretation of high-throughput "omics" data. Statistical and combinatorial methods allow to obtain mechanistic insights through the extraction of smaller subnetwork modules. Further enrichment analyses provide set-based annotations of these modules. Results. We present eXamine, a set-oriented visual analysis approach for annotated modules that displays set membership as contours on top of a node-link layout. Our approach extends upon Self Organizing Maps to simultaneously lay out nodes, links, and set contours. Conclusions. We implemented eXamine as a freely available Cytoscape app. Using eXamine we study a module that is activated by the virally-encoded G-protein coupled receptor US28 and formulate a novel hypothesis about its functioning
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