8,328 research outputs found
Optimum frequency modulation receivers
Optimization of receivers for demodulating FM SIGNAL corrupted by Gaussian noise, and solution to maximum likelihood equatio
A geogenic approach for the Radon monitoring and the exposure assessment at a regional scale: The results of the Rad_Campania project
Abstract. The aim of this paper is to analyse and discuss the
results of the regional program Rad Campania for the monitoring and the
assessment of the radon risk. An innovative methodology, based on a geogenic
approach, was developed, supported by a comprehensive campaign of radon
measurement performed in soil gas, natural waters, drinking natural water
samples and indoor air. Data refer to field measurements carried out in
three provinces of the Campania Region (Italy): Salerno, Avellino and
Benevento. The programme was completed with the main purpose to investigate
the peculiarities of the radon issue at a provincial scale and to redact a
map of the radon potential from soil as a tool for authorities to recognise
critical areas ("Radon prone areas") to monitor. Since the experience
demonstrates that the high radon potential from soil is not indicative of
high indoor radon concentrations, in this paper the authors have tried to
identify a possible general correlation between geological features of the
soil and structural characteristics of the buildings, elaborating more in
depth all data collected. The main purpose is to categorize and analyse the
performance of different kind of construction, typical of the local area, in
order to develop, in a future work, an indicator of the building
performances as a useful tool, for authorities, to recognise constructions
potentially more exposed to high indoor radon activity concentrations.
Results and perspectives have been discussed
WEIGHTBIT: An advancement in wearable technology
Wearable devices are becoming an important interface between users and fitness activities. Their capabilities are improving exponentially, and new strategies are being developed to track sports using sensors that are widely used in robotics. These wearable gadgets are normally created in conjunction with smartphone applications enabling the user to visualise the data and share it through social networks, or compete with other users. The technology behind these devices is often simple using sensors that can be found in a smartphone, such as GPS, accelerometer and gyroscope. However, there are currently no devices capable of measuring the gym activity of weight lifting. In this paper, we present WeightBit: a system consisting of technologically enhanced gym gloves, comprised of the aforementioned sensorâs as well as an additional weight sensor to detect weight and arm movements. Using this data in combination with a smartphone application, it will be possible to monitor a new series of sports activities with specific focus on weight training. Furthermore, the data collected by the application will enable broader research by medical researchers or institutions. The goal is to keep users focused and keen to live a healthy life, providing them a great tool to track their progress, and to develop a system that will allow medical institutions access to this data for further study
Using object-based geomorphometry for hydro-geomorphological analysis in a Mediterranean research catchment
Abstract. The aim of the paper is to apply an object-based geomorphometric procedure to define the runoff contribution areas and support a hydro-geomorphological analysis of a 3âŻkm2 Mediterranean research catchment (southern Italy). Daily and sub-hourly discharge and electrical conductivity data were collected and recorded during a 3-year monitoring activity. Hydro-chemograph analyses carried out on these data revealed a strong seasonal hydrological response in the catchment that differed from the stormflow events that occur in the wet periods and in dry periods. This analysis enabled us to define the hydro-chemograph signatures related to increasing flood magnitude, which progressively involves various runoff components (baseflow, subsurface flow and surficial flow) and an increasing contributing area to discharge. Field surveys and water table/discharge measurements carried out during a selected storm event enabled us to identify and map specific runoff source areas with homogeneous geomorphological units previously defined as hydro-geomorphotypes (spring points, diffuse seepage along the main channel, seepage along the riparian corridors, diffuse outflow from hillslope taluses and concentrate sapping from colluvial hollows). Following the procedures previously proposed and used by authors for object-based geomorphological mapping, a hydro-geomorphologically oriented segmentation and classification was performed with the eCognition (Trimble, Inc.) package. The best agreement with the expert-based geomorphological mapping was obtained with weighted plan curvature at different-sized windows. By combining the hydro-chemical analysis and object-based hydro-geomorphotype map, the variability of the contribution areas was graphically modeled for the selected event, which occurred during the wet season, by using the log values of flow accumulation that better fit the contribution areas. The results allow us to identify the runoff component on hydro-chemographs for each time step and calculate a specific discharge contribution from each hydro-geomorphotype. This kind of approach could be useful when applied to similar, rainfall-dominated, forested and no-karst catchments in the Mediterranean eco-region
Towards a fully automated computation of RG-functions for the 3- O(N) vector model: Parametrizing amplitudes
Within the framework of field-theoretical description of second-order phase
transitions via the 3-dimensional O(N) vector model, accurate predictions for
critical exponents can be obtained from (resummation of) the perturbative
series of Renormalization-Group functions, which are in turn derived
--following Parisi's approach-- from the expansions of appropriate field
correlators evaluated at zero external momenta.
Such a technique was fully exploited 30 years ago in two seminal works of
Baker, Nickel, Green and Meiron, which lead to the knowledge of the
-function up to the 6-loop level; they succeeded in obtaining a precise
numerical evaluation of all needed Feynman amplitudes in momentum space by
lowering the dimensionalities of each integration with a cleverly arranged set
of computational simplifications. In fact, extending this computation is not
straightforward, due both to the factorial proliferation of relevant diagrams
and the increasing dimensionality of their associated integrals; in any case,
this task can be reasonably carried on only in the framework of an automated
environment.
On the road towards the creation of such an environment, we here show how a
strategy closely inspired by that of Nickel and coworkers can be stated in
algorithmic form, and successfully implemented on the computer. As an
application, we plot the minimized distributions of residual integrations for
the sets of diagrams needed to obtain RG-functions to the full 7-loop level;
they represent a good evaluation of the computational effort which will be
required to improve the currently available estimates of critical exponents.Comment: 54 pages, 17 figures and 4 table
Postoperative acute kidney injury defined by RIFLE criteria predicts early health outcome and long-term survival in patients undergoing redo coronary artery bypass graft surgery
AbstractObjectiveTo investigate the impact of postoperative acute kidney injury (AKI) on early health outcome and on long-term survival in patients undergoing redo coronary artery bypass grafting (CABG).MethodsWe performed a Cox analysis with 398 consecutive patients undergoing redo CABG over a median follow-up of 7Â years (interquartile range, 4-12.2Â years). Renal function was assessed using baseline and peak postoperative levels of serum creatinine. AKI was defined according to the risk, injury, failure, loss, and end-stage (RIFLE) criteria. Health outcome measures included the rate of in-hospital AKI and all-cause 30-day and long-term mortality, using data from the United Kingdom's Office of National Statistics. Propensity score matching, as well as logistic regression analyses, were used. The impact of postoperative AKI at different time points was related to survival.ResultsIn patients with redo CABG, the occurrence of postoperative AKI was associated with in-hospital mortality (odds ratio [OR], 3.74; 95% confidence interval [CI], â1.3 to 10.5; PÂ <Â .01], high Euroscore (OR, 1.27; 95% CI, 1.07-1.52; PÂ <Â .01), use of IABP (OR, 6.9; 95% CI, 2.24-20.3; PÂ <Â .01), and reduced long-term survival (hazard ratio [HR], 2.42; 95% CI, 1.63-3.6; PÂ =Â .01). Overall survival at 5 and 10Â years was lower in AKI patients with AKI compared with those without AKI (64% vs 85% at 5Â years; 51% vs 68% at 10Â years). On 1:1 propensity score matching analysis, postoperative AKI was independently associated with reduced long term survival (HR, 2.8; 95% CI, 1.15-6.7).ConclusionsIn patients undergoing redo CABG, the occurrence of postoperative AKI is associated with increased 30-day mortality and major complications and with reduced long-term survival
Self-Averaging in the Three Dimensional Site Diluted Heisenberg Model at the critical point
We study the self-averaging properties of the three dimensional site diluted
Heisenberg model. The Harris criterion \cite{critharris} states that disorder
is irrelevant since the specific heat critical exponent of the pure model is
negative. According with some analytical approaches \cite{harris}, this implies
that the susceptibility should be self-averaging at the critical temperature
(). We have checked this theoretical prediction for a large range of
dilution (including strong dilution) at critically and we have found that the
introduction of scaling corrections is crucial in order to obtain
self-averageness in this model. Finally we have computed critical exponents and
cumulants which compare very well with those of the pure model supporting the
Universality predicted by the Harris criterion.Comment: 11 pages, 11 figures, 14 tables. New analysis (scaling corrections in
the g2=0 scenario) and new numerical simulations. Title and conclusions
chang
QCD matter within a quasi-particle model and the critical end point
We compare our quasi-particle model with recent lattice QCD results for the
equation of state at finite temperature and baryo-chemical potential. The
inclusion of the QCD critical end point into models is discussed. We propose a
family of equations of state to be employed in hydrodynamical calculations of
particle spectra at RHIC energies and compare with the differential azimuthal
anisotropy of strange and charm hadrons.Comment: talk at Quark Matter 2005, August 4 - 9, 2005, Budapest, Hungar
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