6,902 research outputs found

    Detection of HPV in cancerous and non-cancerous esophageal tissues from Turkmen-Sahra, Iran

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    The aim of this study were to assess the presence of HPV esophageal infection among Iranian Turkmen who live in an area located in the cancer belt in Asia. The specimens derived from 120 patients previously diagnosed for Squamous Cell Carcinoma (SCC) non-cancerous tissue derived from esophagus. All specimens were examined for the presence of HPV DNA PCR was utilized to amplify a 150 bp segment of HPV L1 gene using the consensus primers. The amplified region was subsequently sequenced to identify the HPV genotypes. The HPV DNA was detected in 49.4% of patients with SCC, and 58% of non-cancerous tissue of esophagus. The positive samples included HPV-16 (46.6%), HPV-6 (24.6%), HPV-66 (8.2%), HPV-52 (4.1%), HPV-18 (2.7%); 14% of cases were positive for more than one type of HPV. The results confirm the presence of HPV in both esophageal cancerous and non-cancerous tissues. These results imply two different interpretations: 1) Due to non-significant difference between the rate of HPV positive in cancerous and non-cancerous tissues, HPV has no important role in esophageal cancers, which is less probable. 2). Because of a highly incidence of esophageal cancer in Turkmen-Sahra region, the HPV is a possible etiologic agent in esophageal carcinogenesis, most probably acting synergistically with physical, chemical, and/or nutritional factors that have previously been found to be related to this malignancy in Turkmen-Sahra. © 2006 Academic Journals Inc., USA

    The impacts of timing constraints on virtual channels multiplexing in interconnect networks

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    Interconnect networks employing wormhole-switching play a critical role in shared memory multiprocessor systems-on-chip (MPSoC) designs, multicomputer systems and system area networks. Virtual channels greatly improve the performance of wormhole-switched networks because they reduce blocking by acting as "bypass" lanes for non-blocked messages. Capturing the effects of virtual channel multiplexing has always been a crucial issue for any analytical model proposed for wormhole-switched networks. Dally has developed a model to investigate the behaviour of this multiplexing which have been widely employed in the subsequent analytical models of most routing algorithms suggested in the literature. It is indispensable to modify Dally's model in order to evaluate the performance of channel multiplexing in more general networks where restrictions such as timing constraints of input arrivals and finite buffer size of queues are common. In this paper we consider timing constraints of input arrivals to investigate the virtual channel multiplexing problem inherent in most current networks. The analysis that we propose is completely general and therefore can be used with any interconnect networks employing virtual channels. The validity of the proposed equations has been verified through simulation experiments under different working conditions

    An Indictment of Bright Line Tests for Honest Services Mail Fraud

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    Sparse matrix-matrix multiplication (SpGEMM) is a computational primitive that is widely used in areas ranging from traditional numerical applications to recent big data analysis and machine learning. Although many SpGEMM algorithms have been proposed, hardware specific optimizations for multi- and many-core processors are lacking and a detailed analysis of their performance under various use cases and matrices is not available. We firstly identify and mitigate multiple bottlenecks with memory management and thread scheduling on Intel Xeon Phi (Knights Landing or KNL). Specifically targeting multi- and many-core processors, we develop a hash-table-based algorithm and optimize a heap-based shared-memory SpGEMM algorithm. We examine their performance together with other publicly available codes. Different from the literature, our evaluation also includes use cases that are representative of real graph algorithms, such as multi-source breadth-first search or triangle counting. Our hash-table and heap-based algorithms are showing significant speedups from libraries in the majority of the cases while different algorithms dominate the other scenarios with different matrix size, sparsity, compression factor and operation type. We wrap up in-depth evaluation results and make a recipe to give the best SpGEMM algorithm for target scenario. A critical finding is that hash-table-based SpGEMM gets a significant performance boost if the nonzeros are not required to be sorted within each row of the output matrix

    A constructive method for decomposing real representations

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    A constructive method for decomposing finite dimensional representations of semisimple real Lie algebras is developed. The method is illustrated by an example. We also discuss an implementation of the algorithm in the language of the computer algebra system {\sf GAP}4.Comment: Final version; to appear in "Journal of Symbolic Computation

    Similarities Between Classical Timelike Geodesics in a Naked Reissner-Nordstrom Singularity Background and the Behaviour of Electrons in Quantum Theory

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    It is generally assumed that naked singularities must be physically excluded, as they could otherwise introduce unpredictable influences in their future null cones. Considering geodesics for a naked Reissner-Nordstrom singularity, it is found that the singularity is effectively clothed by its repulsive nature. Regarding electron as naked singularity, the size of the clothed singularity (electron) turns out to be classical electro-magnetic radius of the electron, to an observer falling freely from infinity, initially at rest. The size shrinks for an observer falling freely from infinity, with a positive initial velocity. For geodetic parameters corresponding to negative energy there are trapped geodesics. The similarity of this picture with that arising in the Quantum Theory is discussed.Comment: 8 pages, 6 figure

    Single-Spin Asymmetries for Small-Angle Pion Production in High-Energy Hadron Collisions

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    Within the framework of a simple model, we study single-spin asymmetries for pion production in hadron-hadron collisions at high-energies with one hadron polarised. The asymmetries are generated via a mechanism of final (initial) state interactions. For peripheral kinematics, when the pion belongs to the fragmentation region of the polarised proton, we find non-zero asymmetries in the high-energy limit. Numerical results and comparision with existing experimental data are presented. We also discuss the relationship with odderon exchange phenomenology.Comment: LaTeX2e, 12 pages, 4 figure files (2 TeX and 2 eps), uses axodraw, and cite packages; submitted to Eur. Phys. J

    Overcoming thermal noise in non-volatile spin wave logic

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    Spin waves are propagating disturbances in magnetically ordered materials, analogous to lattice waves in solid systems and are often described from a quasiparticle point of view as magnons. The attractive advantages of Joule-heat-free transmission of information, utilization of the phase of the wave as an additional degree of freedom and lower footprint area compared to conventional charge-based devices have made spin waves or magnon spintronics a promising candidate for beyond-CMOS wave-based computation. However, any practical realization of an all-magnon based computing system must undergo the essential steps of a careful selection of materials and demonstrate robustness with respect to thermal noise or variability. Here, we aim at identifying suitable materials and theoretically demonstrate the possibility of achieving error-free clocked non-volatile spin wave logic device, even in the presence of thermal noise and clock jitter or clock skew.Comment: 31 pages including supplementary informatio

    Asymptotic Behaviour of the Proper Length and Volume of the Schwarzschild Singularity

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    Though popular presentations give the Schwarzschild singularity as a point it is known that it is spacelike and not timelike. Thus it has a "length" and is not a "point". In fact, its length must necessarily be infinite. It has been proved that the proper length of the Qadir-Wheeler suture model goes to infinity [1], while its proper volume shrinks to zero, and the asymptotic behaviour of the length and volume have been calculated. That model consists of two Friedmann sections connected by a Schwarzschild "suture". The question arises whether a similar analysis could provide the asymptotic behaviour of the Schwarzschild black hole near the singularity. It is proved here that, unlike the behaviour for the suture model, for the Schwarzschild essential singularity Δs\Delta s \thicksim K1/3lnKK^{1/3}\ln K and VV\thicksim K1lnKK^{-1}\ln K, where KK is the mean extrinsic curvature, or the York time.Comment: 13 pages, 1 figur
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