4,100 research outputs found

    New Variants of Pattern Matching with Constants and Variables

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    Given a text and a pattern over two types of symbols called constants and variables, the parameterized pattern matching problem is to find all occurrences of substrings of the text that the pattern matches by substituting a variable in the text for each variable in the pattern, where the substitution should be injective. The function matching problem is a variant of it that lifts the injection constraint. In this paper, we discuss variants of those problems, where one can substitute a constant or a variable for each variable of the pattern. We give two kinds of algorithms for both problems, a convolution-based method and an extended KMP-based method, and analyze their complexity.Comment: 15 pages, 2 figure

    Heat flow method to Lichnerowicz type equation on closed manifolds

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    In this paper, we establish existence results for positive solutions to the Lichnerowicz equation of the following type in closed manifolds -\Delta u=A(x)u^{-p}-B(x)u^{q},\quad in\quad M, where p>1,q>0p>1, q>0, and A(x)>0A(x)>0, B(x)≄0B(x)\geq0 are given smooth functions. Our analysis is based on the global existence of positive solutions to the following heat equation {ll} u_t-\Delta u=A(x)u^{-p}-B(x)u^{q},\quad in\quad M\times\mathbb{R}^{+}, u(x,0)=u_0,\quad in\quad M with the positive smooth initial data u0u_0.Comment: 10 page

    Dealing with a traumatic past: the victim hearings of the South African truth and reconciliation commission and their reconciliation discourse

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    In the final years of the twentieth and the beginning of the twenty-first century, there has been a worldwide tendency to approach conflict resolution from a restorative rather than from a retributive perspective. The South African Truth and Reconciliation Commission (TRC), with its principle of 'amnesty for truth' was a turning point. Based on my discursive research of the TRC victim hearings, I would argue that it was on a discursive level in particular that the Truth Commission has exerted/is still exerting a long-lasting impact on South African society. In this article, three of these features will be highlighted and illustrated: firstly, the TRC provided a discursive forum for thousands of ordinary citizens. Secondly, by means of testimonies from apartheid victims and perpetrators, the TRC composed an officially recognised archive of the apartheid past. Thirdly, the reconciliation discourse created at the TRC victim hearings formed a template for talking about a traumatic past, and it opened up the debate on reconciliation. By discussing these three features and their social impact, it will become clear that the way in which the apartheid past was remembered at the victim hearings seemed to have been determined, not so much by political concerns, but mainly by social needs

    Esposé des applications de l'électricité

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    Taques d'ĂČxidContĂ©: 1. Notions technicologiques. 2. Applications mĂ©caniques de l'Ă©lectricitĂ©. 3. Applications mĂ©caniques, physiques et physiologiques. 4. Revue des dĂ©couvertes faites en 1857 et 1858. 5. Revue des dĂ©couvertes faites en 1859 et 1862Ăšme. Ă©d

    Susceptibility functions for slow relaxation processes in supercooled liquids and the search for universal relaxation patterns

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    In order to describe the slow response of a glass former we discuss some distribution of correlation times, e.g., the generalized gamma distribution (GG) and an extension thereof (GGE), the latter allowing to reproduce a simple peak susceptibility such as of Cole-Davidson type as well as a susceptibility exhibiting an additional high frequency power law contribution (excess wing). Applying the GGE distribution to the dielectric spectra of glass formers exhibiting no beta-process peak (glycerol, propylene carbonate and picoline) we are able to reproduce the salient features of the slow response (1e-6 Hz - 1e9 Hz). A line shape analysis is carried out either in the time or frequency domain and in both cases an excess wing can be identified. The latter evolves in a universal way while cooling and shows up for correlation times tau_alpha > 1e-8 s. It appears that its first emergence marks the break down of the high temperature scenario of mode coupling theory. - In order to describe a glass former exhibiting a beta-process peak we have introduced a distribution function which is compatible with assuming a thermally activated process in contrast to some commonly used fit functions. Together with the GGE distribution this function allows in the frame of the Williams-Watts approach to completely interpolate the spectra, e.g. of fluoro aniline (1e-6 Hz - 1e9 Hz). The parameters obtained indicate an emergence of both the excess wing and the beta-process again at tau_alpha > 1e-8s.Comment: 22 pages, 12 figure

    Controlled interfacial assembly of 2D curved colloidal crystals and jammed shells

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    Assembly of colloidal particles on fluid interfaces is a promising technique for synthesizing two-dimensional micro-crystalline materials useful in fields as diverse as biomedicine1, materials science2, mineral flotation3 and food processing4. Current approaches rely on bulk emulsification methods, require further chemical and thermal treatments, and are restrictive with respect to the materials employed5-9. The development of methods that exploit the great potential of interfacial assembly for producing tailored materials have been hampered by the lack of understanding of the assembly process. Here we report a microfluidic method that allows direct visualization and understanding of the dynamics of colloidal crystal growth on curved interfaces. The crystals are periodically ejected to form stable jammed shells, which we refer to as colloidal armour. We propose that the energetic barriers to interfacial crystal growth and organization can be overcome by targeted delivery of colloidal particles through hydrodynamic flows. Our method allows an unprecedented degree of control over armour composition, size and stability.Comment: 18 pages, 5 figure

    Role of mTOR through Autophagy in Esophageal Cancer Stemness

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    SIMPLE SUMMARY: Esophageal cancer (EC) is a highly aggressive disease with a poor prognosis, which seems related to esophageal cancer stem-like cells (CSCs), which reside in a hypoxic niche. We demonstrated, using EC cell lines and patient-derived organoids, that the hypoxia-responding mammalian target of rapamycin (mTOR) can suppress autophagy and stemness of esophageal CSCs. In addition, mTOR inhibitor Torin-1-mediated CSCs upregulation was significantly reduced in cells treated with autophagy inhibitor, hydroxychloroquine (HCQ). Collectively, our data suggest that autophagy may play a crucial role in mTOR-mediated CSCs repression. The mTOR pathway could be a novel therapeutic target for putative esophageal CSCs. ABSTRACT: Esophageal cancer (EC) is a highly aggressive disease with a poor prognosis. Therapy resistance and early recurrences are major obstacles in reaching a better outcome. Esophageal cancer stem-like cells (CSCs) seem tightly related with chemoradiation resistance, initiating new tumors and metastases. Several oncogenic pathways seem to be involved in the regulation of esophageal CSCs and might harbor novel therapeutic targets to eliminate CSCs. Previously, we identified a subpopulation of EC cells that express high levels of CD44 and low levels of CD24 (CD44(+)/CD24(−)), show CSC characteristics and reside in hypoxic niches. Here, we aim to clarify the role of the hypoxia-responding mammalian target of the rapamycin (mTOR) pathway in esophageal CSCs. We showed that under a low-oxygen culture condition and nutrient deprivation, the CD44(+)/CD24(−) population is enriched. Since both low oxygen and nutrient deprivation may inhibit the mTOR pathway, we next chemically inhibited the mTOR pathway using Torin-1. Torin-1 upregulated SOX2 resulted in an enrichment of the CD44(+)/CD24(−) population and increased sphere formation potential. In contrast, stimulation of the mTOR pathway using MHY1485 induced the opposite effects. In addition, Torin-1 increased autophagic activity, while MHY1485 suppressed autophagy. Torin-1-mediated CSCs upregulation was significantly reduced in cells treated with autophagy inhibitor, hydroxychloroquine (HCQ). Finally, a clearly defined CD44(+)/CD24(−) CSC population was detected in EC patients-derived organoids (ec-PDOs) and here, MHY1485 also reduced this population. These data suggest that autophagy may play a crucial role in mTOR-mediated CSCs repression. Stimulation of the mTOR pathway might aid in the elimination of putative esophageal CSCs

    Universal and non-universal features of glassy relaxation in propylene carbonate

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    It is demonstrated that the susceptibility spectra of supercooled propylene carbonate as measured by depolarized-light-scattering, dielectric-loss, and incoherent quasi-elastic neutron-scattering spectroscopy within the GHz window are simultaneously described by the solutions of a two-component schematic model of the mode-coupling theory (MCT) for the evolution of glassy dynamics. It is shown that the universal beta-relaxation-scaling laws, dealing with the asymptotic behavior of the MCT solutions, describe the qualitative features of the calculated spectra. But the non-universal corrections to the scaling laws render it impossible to achieve a complete quantitative description using only the leading-order-asymptotic results.Comment: 37 pages, 16 figures, to be published in Phys. Rev.

    The ηâ€Čg∗g∗\eta^\prime g^* g^* vertex with arbitrary gluon virtualities in the perturbative QCD hard scattering approach

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    We study the ηâ€Čg∗g∗\eta^\prime g^* g^* vertex for arbitrary gluon virtualities in the time-like and space-like regions, using the perturbative QCD hard scattering approach and an input wave-function of the ηâ€Č\eta^\prime-meson consistent with the measured ηâ€Čγ∗γ\eta^\prime \gamma^* \gamma transition form factor. The contribution of the gluonic content of the ηâ€Č\eta^\prime-meson is taken into account, enhancing the form factor over the entire virtuality considered. However, data on the electromagnetic transition form factor of the ηâ€Č\eta^\prime-meson is not sufficient to quantify the gluonic enhancement. We also study the effect of the transverse momenta of the partons in the ηâ€Č\eta^\prime-meson on the ηâ€Čg∗g∗\eta^\prime g^* g^* vertex, using the modified hard scattering approach based on Sudakov formalism. Analytic expressions for the ηâ€Čg∗g∗\eta^\prime g^* g^* vertex are presented in limiting kinematic regions and parametrizations are given satisfying the QCD anomaly, for real gluons, and perturbative QCD behavior for large gluon virtualities, in both the time-like and space-like regions. Our results have implications for the inclusive decay B→ηâ€ČXB \to \eta^\prime X and exclusive decays, such as B→ηâ€Č(K,K∗)B \to \eta^\prime (K,K^*), and in hadronic production processes N+N(Nˉ)→ηâ€ČXN + N (\bar N) \to \eta^\prime X.Comment: 23 pages, 19 figures (requires revtex4, amssymb, epsf); several typos corrected, this version now identical to the one accepted for publication in Phys. Rev.

    Cubic boron nitride: a new prospective material for ultracold neutron application

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    For the first time, the neutron optical wall-potential of natural cubic boron nitride (cBN) was measured at the ultracold neutron (UCN) source of the research reactor TRIGA Mainz using the time-of-flight method (TOF). The samples investigated had a wall-potential of (305 +/- 15) neV. This value is in good agreement with the result extracted from neutron reflectometry data and theoretical expectations. Because of its high critical velocity for UCN and its good dielectric characteristics, cubic boron nitride coatings (isotopically enriched) will be useful for a number of applications in UCN experiments
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