6,178 research outputs found

    Cluster decomposition, T-duality, and gerby CFT's

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    In this paper we study CFT's associated to gerbes. These theories suffer from a lack of cluster decomposition, but this problem can be resolved: the CFT's are the same as CFT's for disconnected targets. Such theories also lack cluster decomposition, but in that form, the lack is manifestly not very problematic. In particular, we shall see that this matching of CFT's, this duality between noneffective gaugings and sigma models on disconnected targets, is a worldsheet duality related to T-duality. We perform a wide variety of tests of this claim, ranging from checking partition functions at arbitrary genus to D-branes to mirror symmetry. We also discuss a number of applications of these results, including predictions for quantum cohomology and Gromov-Witten theory and additional physical understanding of the geometric Langlands program.Comment: 61 pages, LaTeX; v2,3: typos fixed; v4: writing improved in several sections; v5: typos fixe

    The effects of transients on photospheric and chromospheric power distributions

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    We have observed a quiet Sun region with the Swedish 1-meter Solar Telescope (SST) equipped with CRISP Imaging SpectroPolarimeter. High-resolution, high-cadence, Hα\alpha line scanning images were taken to observe different layers of the solar atmosphere from the photosphere to upper chromosphere. We study the distribution of power in different period-bands at different heights. Power maps of the upper photosphere and the lower chromosphere show suppressed power surrounding the magnetic-network elements, known as "magnetic shadows". These also show enhanced power close to the photosphere, traditionally referred to as "power halos". The interaction between acoustic waves and inclined magnetic fields is generally believed to be responsible for these two effects. In this study we explore if small-scale transients can influence the distribution of power at different heights. We show that the presence of transients, like mottles, Rapid Blueshifted Excursions (RBEs) and Rapid Redshifted Excursions (RREs), can strongly influence the power-maps. The short and finite lifetime of these events strongly affects all powermaps, potentially influencing the observed power distribution. We show that Doppler-shifted transients like RBEs and RREs that occur ubiquitously, can have a dominant effect on the formation of the power halos in the quiet Sun. For magnetic shadows, transients like mottles do not seem to have a significant effect in the power suppression around 3 minutes and wave interaction may play a key role here. Our high cadence observations reveal that flows, waves and shocks manifest in presence of magnetic fields to form a non-linear magnetohydrodynamic system.Comment: 11 pages, 11 Figures, 4 movies (will be available online in ApJ). ApJ (accepted

    Redescription of the sole species of the enigmatic solifuge genus Dinorhax Simon, 1879 (Solifugae: Melanoblossiidae) in Southeast Asia

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    We present the first recorded description of females of the species Dinorhax rostrumpsittaci (Simon, 1877) from solifugae specimens obtained from southern Vietnam. As a result of DNA barcoding using males identified as D. rostrumpsittaci and unidentified females, these female specimens made a highly supported cluster with male D. rostrumpsittaci. Hereby, we describe the female D. rostrumpsittaci and its natural habitats

    Measurement of miniband parameters of a doped superlattice by photoluminescence in high magnetic fields

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    We have studied a 50/50\AA superlattice of GaAs/Al0.21_{0.21}Ga0.79_{0.79}As composition, modulation-doped with Si, to produce n=1.4×1012n=1.4\times 10^{12} cm−2^{-2} electrons per superlattice period. The modulation-doping was tailored to avoid the formation of Tamm states, and photoluminescence due to interband transitions from extended superlattice states was detected. By studying the effects of a quantizing magnetic field on the superlattice photoluminescence, the miniband energy width, the reduced effective mass of the electron-hole pair, and the band gap renormalization could be deduced.Comment: minor typing errors (minus sign in eq. (5)

    PVD-grown antibacterial Ag-TiN films on piezoelectric PVDF substrates for sensor applications

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    This work reports on Ti1-xAgx and Ag-TiNx electrodes deposited by dc/pulsed dc magnetron sputtering at room temperature on poly (vinylidene fluoride) (PVDF) with the purpose to develop sensors for prosthesis. In Ti1-xAgx electrodes, silver content was varied from 0 to 100 at.%; and for Ag-TiNx electrodes, the nitrogen content was varied between 34 to 43 at.% and the Ti/Ag ratio changed from 12.2 to 5.2. The antibacterial activity of the samples was assessed by agar diffusion method. Interestingly, samples from the Ag-TiNx series presented antibacterial activity, in contrast to the samples from Ti1-xAgx series. XPS results showed that the as-deposited samples from the Ag-TiNx series exhibited silver clusters smaller than 4 nm. In order to deepen the results obtained, samples were analysed after the Halo test (antibacterial test), and XPS analyses showed the disappearance of these Ag clusters in agreement with the SEM results, which displayed a visible aggregation and a significant decrease in the number of Ag clusters, suggesting that silver nanoparticles aggregated and diffused through the agar killing bacteria or inhibiting their grown in the vicinity. All results show that Ag-TiNx electrodes are more promising candidates to be used in PVDF sensor protection than Ti1-xAgx electrodesS. M. Marques gratefully acknowledges the funding from the Portuguese National funds through the FCT - Fundacao para a Ciencia e a Tecnologia, (project SFRH/BD/71259/2010). Also, the authors thank the support of FEDER through the COMPETE Programme and of the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2014 and the project Matepro-Optimizing Materials and Processes, ref. NORTE-07-0124-FEDER-000037", co-funded by the "Programa Operacional Regional do Norte" (ON.2 - O Novo Norte), under the "Quadro de Referencia Estrategico Nacional" (QREN), through the "Fundo Europeu de Desenvolvimento Regional" (FEDER).The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes", REF. NORTE-07-0124-FEDER-000028 co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER.The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the Project "BioHealth Biotechnology and Bioengineering approaches to improve health quality", Ref. NORTE-07-0124-FEDER-000027, co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER.The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the Project "BioEnv Biotechnology and Bioengineering for a sustainable world", REF. NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 0 Novo Norte), QREN, FEDER

    Congenital Syphilis Still Exists! A12-Years Retrospective Analysis of a Reference Maternity

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    Objectivos: Estudar a prevalĂȘncia, factores de risco, evolução clĂ­nica e abordagem terapĂȘutica da sĂ­filis congĂ©nita em recĂ©m-nascidos (RN) de risco, nascidos numa maternidade de referĂȘncia com apoio perinatal diferenciado. MĂ©todo: Realizou-se um estudo transversal para cĂĄlculo de prevalĂȘncia Ă  nascença de sĂ­filis congĂ©nita, entre Janeiro de 1993 e Dezembro de 2004, atravĂ©s de recolha de dados registados nos processos clĂ­nicos das mĂŁes e respectivos RN. De acordo com os critĂ©rios definidos pelo Centers for Disease Control and Prevention (CDC) em 1989, os RN filhos de mĂŁe com VDRL e/ou TPHA positivo foram divididos em trĂȘs grupos de risco. Resultados: Foram identificados 467 recĂ©m-nascidos, verificando-se que a prevalĂȘncia de risco de sĂ­filis congĂ©nita Ă  nascença se tem mantido ao longo dos anos (5,6‰). A maioria dos recĂ©m-nascidos (65%) enquadra-se no grupo de maior risco. Dezanove RN (4%) apresentaram sĂ­filis congĂ©nita sintomĂĄtica ao nascimento, a maioria pertencente ao grupo de maior risco. Outros factores de risco encontrados foram a gravidez nĂŁo-vigiada, em 30% das mĂŁes, toxicodependĂȘncia em 9%, coinfecção por vĂ­rus da hepatite B em 5%, por vĂ­rus da hepatite C em 4,7% e por vĂ­rus de imunodeficiĂȘncia humana em 3,4% dos casos. Em alguns casos existia mais do que um factor de risco associado. ConclusĂ”es: Verificou-se que a prevalĂȘncia de risco de sĂ­filis congĂ©nita nĂŁo sofreu grandes variaçÔes ao longo dos doze anos, pelo que a sĂ­filis continua a constituir um problema de SaĂșde PĂșblica em Portugal, com custos econĂłmicos e sociais

    PVD-grown antimicrobial thin films on PVDF substrates for sensors applications

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    Electroactive polymers are the most interesting class of polymers used as smart materials in various applications, such as the development of sensors and actuators for biomedical applications in areas as smart prosthesis, implantable biosensors and biomechanical signal monitoring, among others. For acquiring or applying the electrical signal from/to the piezoelectric material, suitable electrodes can be produced from Ti based coatings with tailored multifunctional properties, as conductivity and antibacterial characteristics, obtained by the inclusion of Ag. This work reports on Ti1-xAgx electrodes and Ag-TiNy electrodes deposited by d. c. and pulsed magnetron sputtering at room temperature on poly(vinylidene fluoride)(PVDF). In the first system (Ti1-xAgx electrodes), silver content was varied from 0-100 at. %. For the second system (Ag-TiNy electrodes), the nitrogen content changed between 0 to 40.3 at. % by increasing the nitrogen gas flow between 0 sccm and 15 sccm and the ratio Ti/Ag changed from 13.4 to 2.2 being clearly the visible decrease on the Ti content in the reactive mode. The X-Ray Diffraction (XRD) results revealed that the deposition conditions preserve the polymer structure and suggested the presence of crystalline Ti phase in pure titanium coating and fcc-Ag phase in pure silver coating for the Ti1-xAgx system. For the Ag-TiNy system it is possible to detect a fcc TiN structure and a fcc Ag phase. Sheet resistivity values show a typical behavior of a binary alloy system, varying between 0.12 and 28.5 /sq for the Ti1-xAgx electrodes. For the second system the sheet resistivity decrease with the nitrogen content from 12.0 /sq with 0 at. % to 2.8 /sq for 40.3 at. % of N. The piezoelectricity of the different samples show similar values, showing values from 19.6 to 27.6 pCN-1 for the Tix-1Agx system and 13.6 pCN-1 as minimum for the Ag- TiNy system, achieved for the highest N content. In order to assess the mechanical behavior of the as-sputtered films, the film/substrate system was loaded unidirectionally using a tensile machine. The stress-strain curves were analyzed and correlated with the structural data. Moreover, the antibacterial activity of the samples was assessed and it was verified that samples from the second series (Ag-TiNy) present antibacterial activity, in contrast of the first series (Ti1-xAgx)

    Pattern of right ventricular pressure fall and its modulation by afterload

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    Pattern of right ventricular pressure (RVP) fall and its afterload dependence were examined by analyzing ventricular pressure curves and corresponding pressure-dP/dt phase planes obtained in both ventricles in the rat heart in situ. Time and value of dP/dt(min), and the time constant tau were measured at baseline and during variable RV afterload elevations, induced by beat-to-beat pulmonary trunk constrictions. RVP and left ventricular pressure (LVP) decays were divided into initial accelerative and subsequent decelerative phases separated by corresponding dP/dt(min). At baseline, LVP fall was decelerative during 4/5 of its course, whereas only 1/3 of RVP decay occurred in a decelerative fashion. During RV afterload elevations, the absolute value of RV-dP/dt(min) and RV-tau increased, whilst time to RV-dP/dt(min) decreased. Concomitantly, the proportion of RVP decay following a decelerative course increased, so that in highly RV afterloaded heartbeats RVP fall became more similar to LVP fall. In conclusion, RVP and LVP decline have distinct patterns, their major portion being decelerative in the LV and accelerative in the RV. In the RV, dP/dt(min), tau and the proportional contribution of accelerative and decelerative phases for ventricular pressure fall are afterload-dependent. Consequently, tau evaluates a relatively much shorter segment of RVP than LVP fall

    DeepCare: A Deep Dynamic Memory Model for Predictive Medicine

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    Personalized predictive medicine necessitates the modeling of patient illness and care processes, which inherently have long-term temporal dependencies. Healthcare observations, recorded in electronic medical records, are episodic and irregular in time. We introduce DeepCare, an end-to-end deep dynamic neural network that reads medical records, stores previous illness history, infers current illness states and predicts future medical outcomes. At the data level, DeepCare represents care episodes as vectors in space, models patient health state trajectories through explicit memory of historical records. Built on Long Short-Term Memory (LSTM), DeepCare introduces time parameterizations to handle irregular timed events by moderating the forgetting and consolidation of memory cells. DeepCare also incorporates medical interventions that change the course of illness and shape future medical risk. Moving up to the health state level, historical and present health states are then aggregated through multiscale temporal pooling, before passing through a neural network that estimates future outcomes. We demonstrate the efficacy of DeepCare for disease progression modeling, intervention recommendation, and future risk prediction. On two important cohorts with heavy social and economic burden -- diabetes and mental health -- the results show improved modeling and risk prediction accuracy.Comment: Accepted at JBI under the new name: "Predicting healthcare trajectories from medical records: A deep learning approach

    Conformity and controversies in the diagnosis, staging and follow-up evaluation of canine nodal lymphoma: a systematic review of the last 15 years of published literature

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    Diagnostic methods used in the initial and post-treatment evaluation of canine lymphoma are heterogeneous and can vary within countries and institutions. Accurate reporting of clinical stage and response assessment is crucial in determining the treatment efficacy and predicting prognosis. This study comprises a systematic review of all available canine multicentric lymphoma studies published over 15 years. Data concerning diagnosis, clinical stage evaluation and response assessment procedures were extracted and compared. Sixty-three studies met the eligibility criteria. Fifty-five (87.3%) studies were non-randomized prospective or retrospective studies. The survey results also expose variations in diagnostic criteria and treatment response assessment in canine multicentric lymphoma. Variations in staging procedures performed and recorded led to an unquantifiable heterogeneity among patients in and between studies, making it difficult to compare treatment efficacies. Awareness of this inconsistency of procedure and reporting may help in the design of future clinical trials
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