929 research outputs found
Diffusion-Based Adaptive Distributed Detection: Steady-State Performance in the Slow Adaptation Regime
This work examines the close interplay between cooperation and adaptation for
distributed detection schemes over fully decentralized networks. The combined
attributes of cooperation and adaptation are necessary to enable networks of
detectors to continually learn from streaming data and to continually track
drifts in the state of nature when deciding in favor of one hypothesis or
another. The results in the paper establish a fundamental scaling law for the
steady-state probabilities of miss-detection and false-alarm in the slow
adaptation regime, when the agents interact with each other according to
distributed strategies that employ small constant step-sizes. The latter are
critical to enable continuous adaptation and learning. The work establishes
three key results. First, it is shown that the output of the collaborative
process at each agent has a steady-state distribution. Second, it is shown that
this distribution is asymptotically Gaussian in the slow adaptation regime of
small step-sizes. And third, by carrying out a detailed large deviations
analysis, closed-form expressions are derived for the decaying rates of the
false-alarm and miss-detection probabilities. Interesting insights are gained.
In particular, it is verified that as the step-size decreases, the error
probabilities are driven to zero exponentially fast as functions of ,
and that the error exponents increase linearly in the number of agents. It is
also verified that the scaling laws governing errors of detection and errors of
estimation over networks behave very differently, with the former having an
exponential decay proportional to , while the latter scales linearly
with decay proportional to . It is shown that the cooperative strategy
allows each agent to reach the same detection performance, in terms of
detection error exponents, of a centralized stochastic-gradient solution.Comment: The paper will appear in IEEE Trans. Inf. Theor
Wireless-based identification and model updating of a skewed highway bridge for structural health monitoring
Vibration-based monitoring was performed on a short-span skewed highway bridge on the basis of wireless measurements. By means of operational modal analysis, highly accurate modal results (frequencies and mode shapes) were extracted by using a self-developed wireless acquisition system, for which the performance was verified in the field. In order to reproduce the experimental modal characteristics, a refined finite element model was manually tuned to reduce the idealization errors and then updated with the sensitivity method to reduce the parametric errors. It was found that to build a reliable Finite element (FE) model for application in structural health monitoring, the effects of superelevation and boundary conditions of a skewed bridge should be taken into account carefully
Investigation on Dabigatran Etexilate and Worsening of Renal Function in Patients with Atrial fibrillation : the IDEA Study
BACKGROUND AND OBJECTIVES:
Warfarin-related nephropathy is an unexplained acute kidney injury, and may occur in patients with supratherapeutic INR, in the absence of overt bleeding. Similar findings have been observed in rats treated with dabigatran etexilate. We conducted a prospective study in dabigatran etexilate-treated patients to assess the incidence of dabigatran-related nephropathy and to investigate the possible correlation between dabigatran plasma concentration (DPC) and worsening renal function.
METHOD:
One hundred and seven patients treated long term with dabigatran etexilate for non-valvular atrial fibrillation (NVAF) were followed up for 90 days. DPC, serum creatinine (SCr) and serum cystatin C were prospectively measured. Ninety five patients had complete follow-up data and were evaluable for primary endpoint.
RESULTS:
Eleven patients had supratherapeutic DPC, defined as DPC higher than 200 ng/ml at study enrolment, but at the end of follow-up no patient showed a persistent increase in SCr. No patients experienced acute kidney injury.
CONCLUSIONS:
Our study shows that no persistent renal detrimental effect is associated with dabigatran treatment. An increase in SCr during dabigatran treatment is reversible and it seems to be unrelated to dabigatran itself
MLIP genotype as a predictor of pharmacological response in primary open-angle glaucoma and ocular hypertension.
Predicting the therapeutic response to ocular hypotensive drugs is crucial for the clinical treatment and management of glaucoma. Our aim was to identify a possible genetic contribution to the response to current pharmacological treatments of choice in a white Mediterranean population with primary open-angle glaucoma (POAG) or ocular hypertension (OH). We conducted a prospective, controlled, randomized, partial crossover study that included 151 patients of both genders, aged 18 years and older, diagnosed with and requiring pharmacological treatment for POAG or OH in one or both eyes. We sought to identify copy number variants (CNVs) associated with differences in pharmacological response, using a DNA pooling strategy of carefully phenotyped treatment responders and non-responders, treated for a minimum of 6 weeks with a beta-blocker (timolol maleate) and/or prostaglandin analog (latanoprost). Diurnal intraocular pressure reduction and comparative genome wide CNVs were analyzed. Our finding that copy number alleles of an intronic portion of the MLIP gene is a predictor of pharmacological response to beta blockers and prostaglandin analogs could be used as a biomarker to guide first-tier POAG and OH treatment. Our finding improves understanding of the genetic factors modulating pharmacological response in POAG and OH, and represents an important contribution to the establishment of a personalized approach to the treatment of glaucoma
The VLA-VIRMOS Deep Field I. Radio observations probing the microJy source population
We have conducted a deep survey (r.m.s noise 17 microJy) with the Very Large
Array (VLA) at 1.4 GHz, with a resolution of 6 arcsec, of a 1 square degree
region included in the VIRMOS VLT Deep Survey. In the same field we already
have multiband photometry down to I(AB)=25, and spectroscopic observations will
be obtained during the VIRMOS VLT survey. The homogeneous sensitivity over the
whole field has allowed to derive a complete sample of 1054 radio sources (5
sigma limit). We give a detailed description of the data reduction and of the
analysis of the radio observations, with particular care to the effects of
clean bias and bandwidth smearing, and of the methods used to obtain the
catalogue of radio sources. To estimate the effect of the resolution bias on
our observations we have modelled the effective angular-size distribution of
the sources in our sample and we have used this distribution to simulate a
sample of radio sources. Finally we present the radio count distribution down
to 0.08 mJy derived from the catalogue. Our counts are in good agreement with
the best fit derived from earlier surveys, and are about 50 % higher than the
counts in the HDF. The radio count distribution clearly shows, with extremely
good statistics, the change in the slope for the sub-mJy radio sources.Comment: 13 pages, Accepted for publication in Astronomy & Astrophysic
Inter-laboratory calibration of quantitative analyses of antibiotic resistance genes
info:eu-repo/semantics/publishedVersio
The VIMOS Integral Field Unit: data reduction methods and quality assessment
With new generation spectrographs integral field spectroscopy is becoming a
widely used observational technique. The Integral Field Unit of the VIsible
Multi-Object Spectrograph on the ESO-VLT allows to sample a field as large as
54" x 54" covered by 6400 fibers coupled with micro-lenses. We are presenting
here the methods of the data processing software developed to extract the
astrophysical signal of faint sources from the VIMOS IFU observations. We focus
on the treatment of the fiber-to-fiber relative transmission and the sky
subtraction, and the dedicated tasks we have built to address the peculiarities
and unprecedented complexity of the dataset. We review the automated process we
have developed under the VIPGI data organization and reduction environment
(Scodeggio et al. 2005), along with the quality control performed to validate
the process. The VIPGI-IFU data processing environment is available to the
scientific community to process VIMOS-IFU data since November 2003.Comment: 19 pages, 10 figures and 1 table. Accepted for publication in PAS
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