1,832 research outputs found

    The complexity of lattice knots

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    AbstractA family of polygonal knots Kn on the cubical lattice is constructed with the property that the quotient of length L(Kn) over the crossing number Cr(Kn) approaches zero as L approaches infinity. More precisely Cr(Kn) = O(L(Kn)43). It is shown that this construction is optimal in the sense that for any knot K on the cubical lattice with length L and Cr crossings Cr ⩽ 3.2L43

    Functional characterization of a gluthathione Stransferase gene from Limonium bicolor in response to several abiotic stresses

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    In the present study, we characterized a gluthathione S-transferase gene (LbGST1) in response to different abiotic stresses. Real time polymerase chain reaction (RT-PCR) indicated that the LbGST1 can be differentially regulated by stress of NaCl, NaHCO3 and low temperature, suggesting a role in plant stress response. To further investigate abiotic stress tolerance of LbGST1, the transgenic yeast harboring the LbGST1 was generated under the control of inducible GAL promoter (pYES2 vector); yeast cells transformed with empty pYES2 were also generated as a control. Stress tolerance tests showed that LbGST1 yeast transformants exhibited elevated tolerance to the stresses of thermal (53°C), alkali (NaHCO3), ultraviolet radiation, salt (NaCl), drought (sorbitol) and freezing (-20°C) compared with the control transformants, suggesting that the LbGST1 is tolerant to these abiotic stresses. Our results indicate that the LbGST1 gene is resistant to a wider repertoire of stresses and may play a common role in plant acclimation to the examined stress conditions.Key words: Gluthathione S-transferases (GST), abiotic stress, expression analysis, Limonium bicolor

    Cancer du testicule: particularités cliniques et limites thérapeutiques en milieu hospitalier urologique au Sénégal

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    RésuméButEtudier les particularités cliniques et les limites thérapeutiques de la prise en charge du cancer du testicule au Sénégal.Patients et méthodesCette étude, rétrospective, était menée sur une période de 15 ans de Janvier 1997 à Janvier 2012. Vingt-deux dossiers étaient colligés mais 17 étaient exploitables.Résultatsl’incidence annuelle moyenne était de 1,13 cas par an. L’âge moyen des patients était de 27 ans ± 9,5. La tranche d’âge la plus concernée était celle de 21 à 40 ans. Les circonstances de découverte étaient dominées par la grosse bourse (10 cas) et en cas de vacuité scrotale, la masse abdominale ou pelvienne (7 cas). L’orchidectomie a été le principal geste thérapeutique. Elle a été réalisée par voie inguinale haute (8 patients) et par voie trans-péritonéale (7 patients). Sur le plan histologique, nous avions noté une prédominance des tumeurs germinales non séminomateuses avec 10 cas de carcinome embryonnaire dont un cas de type infantile. En post opératoire, 7 cas de progression avaient été notés dans le suivi: 3 cas de carcinose péritonéale, 3 cas d’envahissement locorégionale avec des adénopathies rétropéritonéale et 1 cas de métastase pulmonaire. Avec un recul moyen de 6 mois, 9 patients étaient décédés, 4 étaient perdus de vue et les 4 autres étaient vivants.ConclusionLe cancer du testicule reste rare au Sénégal et concerne des sujets jeunes. Le diagnostic est encore posé à des stades très évolués avec une lourde mortalité.AbstractObjectiveTo investigate the clinical features and limitations of therapeutic management of testicular cancer in Senegal.Patients and methodsThis is a retrospective study over 15 years period between January 1997 and January 2012. Twenty-two cases were collected but only 17 had complete data for analysis.ResultsThe average annual incidence was 1.13 cases per year, with a mean age of 27±9.5 years. The most affected age group was between 21 and 40 years.Clinical diagnosis was suspected by the presence of a scrotal swelling in10 cases and by empty scrotum associated with abdominal or pelvic mass in the remaining 7 cases. Orchiectomy was the main treatment option, done either by high inguinal approach in 8 patients or by trans- peritoneal route in other 7 patients. Histologically, a predominance of embryonic non seminomatous germ cell carcinoma was noted in 10 cases including infantile type in one case. Seven cases developed disease progression:3 cases of peritoneal carcinmatosis, 3 other cases of locoregional invasion with retroperitoneal lymphadenopathy and one case of pulmonary metastasis. At a mean follow up of six months, nine patients died, four were lost to follow up while the remaining four cases were still alive.ConclusionTesticular cancer is a rare tumor in Senegal and usually involves young people. Clinical diagnosis is always done at very advanced stage with a very high mortality rate

    TO ACHIEVE REAL IMMERSION: THE 3D VIRTUAL AND PHYSICAL RECONSTRUCTION OF CAVE 3 AND CAVE 12 OF YUNGANG GROTTOES

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    As the 3D laser scanning and photogrammetry technologies continue to mature, more and more applications founded in numerous areas. The realistic 3D models are mainly adopted for digital display uses, such as the 3D game, web showcases, head-mounted display, etc. While we are enjoying the vivid digital sceneries through different kinds of digital display screens, there are still challenges exist for the 3D printing application, especially for large size objects. In this article, we will present an approach on digitizing and 3D replicating large grottoes. Unlike 3D rendering, 3D printing requires high detailed shape data for the fabrication. Such demands cause many technical difficulties including huge data amount, accurate dense point cloud, high-resolution texture mapping. We chose cascade SfM, grouped MVS, automatic texture mapping to prepare the high definition colored 3D model for printing and painting references. Meanwhile, we optimized 3D printing procedure as well as post-processing, installation, lacquer and painting. Two replicas of 10- meter sized grottoes have been manufactured after four years of efforts, which have earned some appreciations from audiences

    Measurements of branching fractions for inclusive K0~/K0 and K*(892)+- decays of neutral and charged D mesons

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    Using the data sample of about 33 pb-1 collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we have studied inclusive K0~/K0 and K*(892)+- decays of D0 and D+ mesons. The branching fractions for the inclusive K0~/K0 and K*(892)- decays are measured to be BF(D0 to K0~/K0 X)=(47.6+-4.8+-3.0)%, BF(D+ to K0~/K0 X)=(60.5+-5.5+-3.3)%, BF(D0 to K*- X)=(15.3+- 8.3+- 1.9)% and BF(D+ to K*- X)=(5.7+- 5.2+- 0.7)%. The upper limits of the branching fractions for the inclusive K*(892)+ decays are set to be BF(D0 to K*+ X)<3.6% and BF(D+ to K*+ X) <20.3% at 90% confidence level

    Direct Measurements of the Branching Fractions for Inclusive K±K^\pm and Inclusive Semileptonic Decays of D+D^+ and D0D^0 Mesons

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    With singly-tagged Dˉ\bar D samples selected from the data collected at and around 3.773 GeV with the BESII detector at the BEPC collider, we have measured the branching fractions for the inclusive K±K^\pm decays of D+D^+ and D0D^0 mesons, which are BF(D+KX)=(24.7±1.3±1.2)BF(D^+\to K^-X) = (24.7 \pm 1.3 \pm 1.2)%, BF(D+K+X)=(6.1±0.9±0.4)BF(D^+\to K^+X) = (6.1 \pm 0.9 \pm 0.4) %, BF(D0KX)=(57.8±1.6±3.2)BF(D^0\to K^-X) = (57.8 \pm 1.6 \pm 3.2) % and BF(D0K+X)=(3.5±0.7±0.3)BF(D^0\to K^+X) = (3.5 \pm 0.7 \pm 0.3) %, respectively. We have also measured the branching fractions for the inclusive semileptonic decays of D+D^+ and D0D^0 mesons to be BF(D+e+X)=(15.2±0.9±0.8)BF(D^+ \to e^+ X)=(15.2 \pm 0.9 \pm 0.8)% and BF(D0e+X)=(6.3±0.7±0.4)BF(D^0 \to e^+ X) =(6.3 \pm 0.7 \pm 0.4) %. These yield the ratio of their partial widths to be Γ(D+e+X)/Γ(D0e+X)=0.95±0.12±0.07\Gamma(D^+ \to e^+X)/\Gamma(D^0 \to e^+X)=0.95 \pm 0.12 \pm 0.07.Comment: 6 pages, 5 figure

    Understanding IoT Security Through the Data Crystal Ball: Where We Are Now and Where We Are Going To Be

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    Inspired by the boom of the consumer IoT market, many device manufacturers, new start-up companies and technology behemoths have jumped into the space. Indeed, in a span of less than 5 years, we have experienced the manifestation of an array of solutions for the smart home, smart cities and even smart cars. Unfortunately, the exciting utility and rapid marketization of IoTs, come at the expense of privacy and security. Online and industry reports, and academic work have revealed a number of attacks on IoT systems, resulting in privacy leakage, property loss and even large-scale availability problems on some of the most influential Internet services (e.g. Netflix, Twitter). To mitigate such threats, a few new solutions have been proposed. However, it is still less clear what are the impacts they can have on the IoT ecosystem. In this work, we aim to perform a comprehensive study on reported attacks and defenses in the realm of IoTs aiming to find out what we know, where the current studies fall short and how to move forward. To this end, we first build a toolkit that searches through massive amount of online data using semantic analysis to identify over 3000 IoT-related articles (papers, reports and news). Further, by clustering such collected data using machine learning technologies, we are able to compare academic views with the findings from industry and other sources, in an attempt to understand the gaps between them, the trend of the IoT security risks and new problems that need further attention. We systemize this process, by proposing a taxonomy for the IoT ecosystem and organizing IoT security into five problem areas. We use this taxonomy as a beacon to assess each IoT work across a number of properties we define. Our assessment reveals that despite the acknowledged and growing concerns on IoT from both industry and academia, relevant security and privacy problems are far from solved. We discuss how each proposed solution can be applied to a problem area and highlight their strengths, assumptions and constraints. We stress the need for a security framework for IoT vendors and discuss the trend of shifting security liability to external or centralized entities. We also identify open research problems and provide suggestions towards a secure IoT ecosystem

    Measurement of \psip Radiative Decays

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    Using 14 million psi(2S) events accumulated at the BESII detector, we report first measurements of branching fractions or upper limits for psi(2S) decays into gamma ppbar, gamma 2(pi^+pi^-), gamma K_s K^-pi^++c.c., gamma K^+ K^- pi^+pi^-, gamma K^{*0} K^- pi^+ +c.c., gamma K^{*0}\bar K^{*0}, gamma pi^+pi^- p pbar, gamma 2(K^+K^-), gamma 3(pi^+pi^-), and gamma 2(pi^+pi^-)K^+K^- with the invariant mass of hadrons below 2.9GeV/c^2. We also report branching fractions of psi(2S) decays into 2(pi^+pi^-) pi^0, omega pi^+pi^-, omega f_2(1270), b_1^\pm pi^\mp, and pi^0 2(pi^+pi^-) K^+K^-.Comment: 5 pages, 4 figure
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