6,178 research outputs found
Cluster decomposition, T-duality, and gerby CFT's
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
We have observed a quiet Sun region with the Swedish 1-meter Solar Telescope
(SST) equipped with CRISP Imaging SpectroPolarimeter. High-resolution,
high-cadence, H 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
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
We have studied a 50/50\AA superlattice of GaAs/AlGaAs
composition, modulation-doped with Si, to produce
cm 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
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
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 (5,6â°). 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
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
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
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
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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