1,324 research outputs found
Destructive Impact of Molecular Noise on Nanoscale Electrochemical Oscillators
We study the loss of coherence of electrochemical oscillations on meso- and
nanosized electrodes with numeric simulations of the electrochemical master
equation for a prototypical electrochemical oscillator, the hydrogen peroxide
reduction on Pt electrodes in the presence of halides. On nanoelectrodes, the
electrode potential changes whenever a stochastic electron-transfer event takes
place. Electrochemical reaction rate coefficients depend exponentially on the
electrode potential and become thus fluctuating quantities as well. Therefore,
also the transition rates between system states become time-dependent which
constitutes a fundamental difference to purely chemical nanoscale oscillators.
Three implications are demonstrated: (a) oscillations and steady states shift
in phase space with decreasing system size, thereby also decreasing
considerably the oscillating parameter regions; (b) the minimal number of
molecules necessary to support correlated oscillations is more than 10 times as
large as for nanoscale chemical oscillators; (c) the relation between
correlation time and variance of the period of the oscillations predicted for
chemical oscillators in the weak noise limit is only fulfilled in a very
restricted parameter range for the electrochemical nano-oscillator.Comment: 18 pages, 9 figure
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Reformas educativas en América Latina en tiempos de crisis
Latin American Studie
The Placental Transcriptome in Late Gestational Hypoxia Resulting in Murine Intrauterine Growth Restriction Parallels Increased Risk of Adult Cardiometabolic Disease.
Intrauterine growth restriction (IUGR) enhances risk for adult onset cardiovascular disease (CVD). The mechanisms underlying IUGR are poorly understood, though inadequate blood flow and oxygen/nutrient provision are considered common endpoints. Based on evidence in humans linking IUGR to adult CVD, we hypothesized that in murine pregnancy, maternal late gestational hypoxia (LG-H) exposure resulting in IUGR would result in (1) placental transcriptome changes linked to risk for later CVD, and 2) adult phenotypes of CVD in the IUGR offspring. After subjecting pregnant mice to hypoxia (10.5% oxygen) from gestational day (GD) 14.5 to 18.5, we undertook RNA sequencing from GD19 placentas. Functional analysis suggested multiple changes in structural and functional genes important for placental health and function, with maximal dysregulation involving vascular and nutrient transport pathways. Concordantly, a ~10% decrease in birthweights and ~30% decrease in litter size was observed, supportive of placental insufficiency. We also found that the LG-H IUGR offspring exhibit increased risk for CVD at 4 months of age, manifesting as hypertension, increased abdominal fat, elevated leptin and total cholesterol concentrations. In summary, this animal model of IUGR links the placental transcriptional response to the stressor of gestational hypoxia to increased risk of developing cardiometabolic disease
Thrombotic and hemorrhagic complications in idiopathic erythrocytosis
We report clinical features of a large cohort of patients with IE compared to a cohort of patients with PV, focusing on the thrombotic and hemorrhagic risk
Comparing SPHINX vs. SONIC Italian Children Speech Recognition Systems
Our previous experiences have showed that both CSLR SONIC and CMU SPHINX are two versatile and powerful tools for Automatic Speech Recognition (ASR). Encouraged by the good results we had, these two systems have been compared in another important challenge of ASR: the recognition of children\u27s speech. In this work, SPHINX has been used to build from scratch a recognizer for Italian children\u27s speech and the results have been compared to those obtained with SONIC, both in previous and in some new experiments, which were designed in order to have uniform experimental conditions between the two different systems. This report describes the training process and the evaluation methodology regarding a speaker-independent phonetic-recognition task. First, we briefly describe the system architectures and their differences, and then we analyze the task, the corpus and the techniques adopted to face the recognition problem. The scores of multiple tests in terms of Phonetic Error Rate (PER) and an analysis on differences of the two systems are shown in the final discussion. SONIC has turned out to have the best overall performance and it obtained a minimum PER of 12.4% with VTLN and SMAPLR adaptation. SPHINX was the easiest system to train and test and its performance (PER of 17.2% with comparable adaptations) was only some percentage points far from those in SONIC
Evalita-Istc Comparison Of Open Source Tools On Clean And Noisy Digits Recognition Tasks
EVALITA is a recent initiative devoted to the evaluation of Natural Language and Speech Processing tools for Italian. The general objective of EVALITA is to promote the development of language and speech technologies for the Italian language, providing a shared framework where different systems and approaches can be evaluated in a consistent manner. In this work the results of the evaluation of three open source ASR toolkits (CSLU Speech Tools, CSLR SONIC, SPHINX) working on the EVALITA clean and noisy digits recognition task will be described together with the complete evaluation methodology
A FACIAL ANIMATION FRAMEWORK WITH EMOTIVE/EXPRESSIVE CAPABILITIES
LUCIA is an MPEG-4 facial animation system developed at ISTC-CNR.. It works on standard Facial Animation Parameters and speaks with the Italian version of FESTIVAL TTS. To achieve an emotive/expressive talking head LUCIA was build from real human data physically extracted by ELITE optotracking movement analyzer. LUCIA can copy a real human by reproducing the movements of passive markers positioned on his face and recorded by the ELITE device or can be driven by an emotional XML tagged input text, thus realizing a true audio/visual emotive/expressive synthesis. Synchronization between visual and audio data is very important in order to create the correct WAV and FAP files needed for the animation. LUCIA\u27s voice is based on the ISTC Italian version of FESTIVAL-MBROLA packages, modified by means of an appropriate APML/VSML tagged language. LUCIA is available in two different versions: an open source framework and the "work in progress" WebG
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