175 research outputs found
Hepatitis C virus (HCV) infection may elicit neutralizing antibodies targeting epitopes conserved in all viral genotypes
Anti-hepatitis C virus (HCV) cross-neutralizing human monoclonal antibodies, directed against conserved epitopes on surface E2 glycoprotein, are central tools for understanding virus-host interplay, and for planning strategies for prevention and treatment of this infection. Recently, we developed a research aimed at identifying these antibody specificities. The characteristics of one of these antibodies (Fab e20) were addressed in this study. Firstly, using immunofluorescence and FACS analysis of cells expressing envelope HCV glycoproteins, Fab e20 was able to recognize all HCV genotypes. Secondly, competition assays with a panel of mouse and rat monoclonals, and alanine scanning mutagenesis analyses located the e20 epitope within the CD81 binding site, documenting that three highly conserved HCV/E2 residues (W529, G530 and D535) are critical for e20 binding. Finally, a strong neutralizing activity against HCV pseudoparticles (HCVpp) incorporating envelope glycoproteins of genotypes 1a, 1b, 2a, 2b and 4, and against the cell culture-grown (HCVcc) JFH1 strain, was observed. The data highlight that neutralizing antibodies against HCV epitopes present in all HCV genotypes are elicited during natural infection. Their availability may open new avenues to the understanding of HCV persistence and to the development of strategies for the immune control of this infection
Flooding Time in Opportunistic Networks under Power Law and Exponential Inter-Contact Times
Performance bounds for opportunistic networks have been derived in a number
of recent papers for several key quantities, such as the expected delivery time
of a unicast message, or the flooding time (a measure of how fast information
spreads). However, to the best of our knowledge, none of the existing results
is derived under a mobility model which is able to reproduce the power
law+exponential tail dichotomy of the pairwise node inter-contact time
distribution which has been observed in traces of several real opportunistic
networks.
The contributions of this paper are two-fold: first, we present a simple
pairwise contact model -- called the Home-MEG model -- for opportunistic
networks based on the observation made in previous work that pairs of nodes in
the network tend to meet in very few, selected locations (home locations); this
contact model is shown to be able to faithfully reproduce the power
law+exponential tail dichotomy of inter-contact time. Second, we use the
Home-MEG model to analyze flooding time in opportunistic networks, presenting
asymptotic bounds on flooding time that assume different initial conditions for
the existence of opportunistic links.
Finally, our bounds provide some analytical evidences that the speed of
information spreading in opportunistic networks can be much faster than that
predicted by simple geometric mobility models
Creazione e validazione di un questionario per la valutazione delle abilità comunicative, relazionali e pedagogiche del tutor clinico dei Corsi di Laurea in Fisioterapia: cross sectional study
INTRODUZIONE: Il tutor clinico è centrale nella formazione dei professionisti sanitari. Nonostante ciò, in Italia non esiste un questionario che permetta agli studenti del Corso di Studi in fisioterapia di valutare il proprio tutor clinico di tirocinio. L’obiettivo del lavoro è creare e validare un questionario per valutare le abilità comunicative, relazionale e pedagogiche del tutor clinico da parte dello studente.
MATERIALI E METODI: In una fase pre-test è stato chiesto ai direttori didattici di valutare chiarezza e comprensibilità del questionario. Lo strumento è stato somministrato agli studenti del Corso di Studi di fisioterapia dell’Università di TorVergata. Quindi è stata svolta una analisi psicometrica del questionario esaminando affidabilità , consistenza interna e validità di costrutto. Quest’ultima è stata indagata confrontando il questionario con il CLEQEI, validato in Italia nel corso di studi in infermieristica.
RISULTATI: La fase Pre-Test ha prodotto un questionario di 27 items suddivisi in 3 macro-aree, che valutano abilità comunicative, relazionali e pedagogiche del tutor. L’intervallo di confidenza interclasse ha un valore di 0,78 (p<0.01). La consistenza interna, valutata tramite l’alfa di Crombach ha come punteggio sul campione 0.961. La validità di costrutto, analizzata tramite la r di Pearson ha correlato le aree dei questionari, il punteggio maggiore è espresso dalla correlazione tra punteggi totali (r=0.753, p<0.01).
DISCUSSIONE: Il questionario risulta riproducibile coerente e valido nel valutare la performance del tutor nel Corso di Studi in Fisioterapia. Il questionario vuole essere un supporto ai direttori didattici, per la valutazione e del tutor al fine di ottimizzare tale servizio
A box model to represent estuarine dynamics in mesoscale resolution ocean models
Representing the net freshwater flux at river mouths is challenging for global and regional scale ocean modelling. Although rivers are well known to affect both the coastal and basin-wide circulation and dynamics, coarse resolution ocean models cannot resolve the estuarine dynamics and are usually forced at river outlets in a simplistic way, with climatological runoff and zero or constant salinity values. The aim of this study is to provide a more realistic representation of the estuarine water inputs to a coarse but eddy-resolving regional model. First, the river volume transport and salinity values at the outlets are modelled with three different Estuary Box Models (EBMs) for stratified estuaries: the Knudsen relations model, a published EBM, called UCONN-NCAR EBM, which parameterizes the tidal inflow and mixing inside the estuary, and a new model, called CMCC-EBM. The CMCC EBM has been conceived to represent the estuarine processes coupled to a mesoscale resolving hydrodynamic model that resolves the entering flow field at the estuary mouth and it offers a new representation of the tidal inflow and a new salinity tidal mixing parameterization via horizontal diffusive processes. The Ofanto and Po rivers flowing into the Adriatic Sea (northern part of the central Mediterranean Sea) are selected as case studies. The coupling of the eddy resolving ocean model to the CMCC EBM is found to outperform the one with the UCONN-NCAR EBM in the region of freshwater influence on the shelf area
The Mediterranean analysis and forecasting physical system for the Copernicus Marine Service: description and skill assessment
The Mediterranean Analysis and Forecasting System is a numerical ocean prediction system that operationally produces analyses and 10 days forecasts of the main physical parameters for the entire Mediterranean Sea and its Atlantic Ocean adjacent areas.
The system is composed by the hydrodynamic model NEMO (Nucleus for European Modelling of the Ocean) 2-way coupled with the third-generation wave model WW3 (WaveWatchIII) and forced by ECMWF (European Centre for Medium-range Weather Forecasts) atmospheric fields. The forecast initial conditions are produced by a 3D variational data assimilation system which considers a daily assimilation cycle of Sea Level Anomaly, vertical profiles of Temperature and Salinity from ARGO and ship CTDs and heat flux corrections with satellite SST.
The system has been recently upgraded in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS) by increasing the grid resolution from 1/16 to 1/24 degree in the horizontal, thus becoming fully mesoscale resolving and from 72 to 141 vertical levels, by increasing the number of fresh water river inputs and by updating the data assimilation scheme. The model has a non-linear explicit free surface and the forecast is forced by surface pressure, interactive heat, momentum and water fluxes at the air-sea interface.
The focus of this work is to present the latest modeling system upgrades and the related improvements achieved by showing the model skill assessment including comparison with independent (insitu coastal moorings) and quasi-independent (insitu vertical profiles and satellite) datasets.PublishedHalifax, Nova Scotia, Canada4A. Oceanografia e clim
Mediterranean Sea Analysis and Forecast (CMEMS MED-Currents 2016-2019)
INGVPublished4A. Oceanografia e clim
Mediterranean Sea Analysis and Forecast (CMEMS MED-Currents 2016-2019)
Copernicus Marine Environment Monitoring ServicePublished4A. Oceanografia e clim
Folding Pathways of Prion and Doppel
The relevance of various residue positions for the stability and the folding
characteristics of the prion protein are investigated by using molecular
dynamics simulations of models exploiting the topology of the native state.
Highly significant correlations are found between the most relevant sites in
our analysis and the single point mutations known to be associated with the
arousal of the genetic forms of prion disease (caused by the conformational
change from the cellular to the scrapie isoform). Considerable insight into the
conformational change is provided by comparing the folding process of prion and
doppel (a newly discovered protein) sharing very similar native state topology:
the folding pathways of the former can be grouped in two main classes according
to which tertiary structure contacts are formed first enroute to the native
state. For the latter a single class of pathways leads to the native state. Our
results are consistent and supportive of the recent experimental findings that
doppel lacks the scrapie isoform and that such remarkably different behavior
results from differences in the region containing the two strands and
the intervening helix.Comment: 16 pages, 2 tables, 5 figure
From microscopic taxation and redistribution models to macroscopic income distributions
We present here a general framework, expressed by a system of nonlinear
differential equations, suitable for the modelling of taxation and
redistribution in a closed (trading market) society. This framework allows to
describe the evolution of the income distribution over the population and to
explain the emergence of collective features based on the knowledge of the
individual interactions. By making different choices of the framework
parameters, we construct different models, whose long-time behavior is then
investigated. Asymptotic stationary distributions are found, which enjoy
similar properties as those observed in empirical distributions. In particular,
they exhibit power law tails of Pareto type and their Lorenz curves and Gini
indices are consistent with some real world ones.Comment: 12 pages, 4 figures. Version submitted to Physica A on Feb 15, 201
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