Search results for "Models"
showing 10 items of 8211 documents
Downregulation of myogenic microRNAs in sub-chronic but not in sub-acute model of daunorubicin-induced cardiomyopathy
2016
Cardiac muscle-related microRNAs play important roles in cardiac development and disease by translational silencing of mRNAs, the dominant mechanism of microRNA action. To test whether they could be involved in daunorubicin-associated cardiomyopathy (DACM), we determined expression patterns of myomiRs in two distinct models of DACM. We used 10â12 weeks old male Wistar rats. In the sub-acute model, rats were administered with six doses of daunorubicin (DAU-A, 3Â mg/kg, i.p., every 48Â h). Rats were sacrificed two days after the last dose. In the sub-chronic model, anaesthetized rats were administered a single dose of daunorubicin (15Â mg/kg, i.v., DAU-C). Age-matched controls (CON) receive…
Role of the colored noise in a FitzHugh-Nagumo system driven by a periodic signal
2007
During these last years the interest in neuronal dynamics increased. The study of this kind of system has been carried out by using the FitzHugh-Nagumo (FHN) model that is a simplified modification of the Hodgkin-Huxley model. Many interesting phenomena can be observed in the presence of fluctuations: modification of detection threshold by manipulation of noisy parameters (FHN model), noise-induced activation and coeherence resonance for suitable noise amplitude (absence of periodic signal), resonant activation for high periodic signals and noise reduction, intrinsic stochastic resonance (ISR) in Hodgkin-Huxley neuron and the enhancement of a weak signal by tuning the subthreshold intrinsic…
Temperature and density structure of hot and cool loops derived from the analysis of TRACE data
2002
We address the plasma structuring both across and along the magnetic field in two sets of solar coronal loops, observed with TRACE in the 17lÅ and 195Å passbands. We derive, after proper background removal, the density stratification and the thermal structure of the plasma in the fibrils forming the loops with two techniques: a) filter ratio diagnostic (195 Å/171 Å) and b) modeling intensity profiles along the fibrils with hydrostatic models. We find evidence of a hot fibril (T ∼ 5·106 K), with temperature and density stratification well-described with a typical non-isothermal hydrostatic loop model, and evidence of rather cold fibrils (T ∼ 2 · 105 K), isothermal and probably in dynamic con…
An Inquiry-Based Approach to Physics Teacher Education: the Case of Sound Properties
2014
In this paper we describe some results of an experimentation on Pre-Service Physics Teacher Education performed with a group of non-Italian Trainee Teachers engaged in one-month mobility activities at University of Palermo, in the framework of the EU Project “Move’in Science”. Some preliminary results of the experimentation of a Teaching/Learning Unit about Mechanical Wave propagation are presented, with particular reference to mental models about wave propagation evidenced by Trainee Teachers. Their understanding of the relevance of pupils’ mental model knowledge, in the framework of what a teacher should do to be an “effective” teacher, is also discussed.
Geological modeling of Altavilla Milicia (Sicily) using HVSR data
2014
At today the use of inversion of HVSR curves is mainly limited to derive average parameters of the shear wave velocity, although recently they have been used also for a detailed reconstruction of the roof of the seismic bedrock (Di Stefano et al. 2014). Since ambient vibrations may contain waves travelling in all directions, as body waves and Rayleigh and Love waves, a limit of this method lies in the uncertain composition of seismic noise, in the lack of knowledge about the microseismic field and in the subjective choices regarding the data processing. This work aims to verify the potential and limits of the HVSR inversion for the purposes of geological reconstruction of the subsoil in hea…
Long-term earthquake potential of active faults by using coastal and off-shore geological and morphological indicators
2017
Seismogenic fault models and active deformation ones coupled with models of both earthquake rate and earthquake probability were recently used in a time-independent modelling. The integration of models allows to estimates the magnitude, location, and likelihood of potentially damaging earthquake ruptures in regions with high natural seismic hazard. Improvements of these models imply the recognition of the spatial geometry of the larger, active faults, deemed to be the source of the most damaging future earthquakes. However, identifying active faults and calculating their geologic slip rates for deriving earthquake rates are not easy tasks in regions inaccessible to direct field studies like…
Multi-parametric GIS analysis to assess gully erosion susceptibility: a test in southern Sicily, Italy
2011
: A GIS-analysis was carried out in a test basin of southern Sicily, the Magazzolo River basin, in order to assess susceptibility conditions to gully erosion phenomena. The linear density of ephemeral and permanent gullies computed within each class of nine environmental variables was used to generate a gully erosion susceptibility map for the area. A validation procedure carried out in order to test the reliability of the adopted method highlighted a clear correlation between the occurrence of gullies and the computed susceptibility levels
Smart Data Blending Framework to Enhance Precipitation Estimation through Interconnected Atmospheric, Satellite, and Surface Variables
2023
Accurate precipitation estimation remains a challenge, though it is fundamental for most hydrological analyses. In this regard, this study aims to achieve two objectives. Firstly, we evaluate the performance of two precipitation products from the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM-IMERG) for Sicily, Italy, from 2016 to 2020 by a set of categorical indicators and statistical indices. Analyses indicate the favorable performance of daily estimates, while half-hourly estimates exhibited poorer performance, revealing larger discrepancies between satellite and ground-based measurements at sub-hourly timescales. Secondly, we propose four multi-source me…
Effects of climate and land use changes on runoff extremes
2017
The analysis of the hydrological changes and their interacting triggering factors are objectives defined within the Panta Rhei decade 2013-2022. Climate change and urbanization are among the most recurrent causes for hydrological changes at the global level. This work proposes a modeling framework for the analysis of the alterations in the watershed hydrological response and, more specifically, in runoff extremes, induced by such perturbations. A weather generator and a cellular automata land-use change model are used to generate hypothetical scenarios accounting for relevant trends at the global level. Such scenarios are successively considered to force a physically-based and spatial-distr…
A performance based approach for the analysis of urban water distribution systems under drought conditions
2009
The present study proposes some performance indicators for analysing urban water distribution system characterised by intermittent supply service. Specific indicators have been proposed for investigating the reduction of quality of water service under resources scarcity conditions. A modelling procedure has been implemented in order to allow for analysing complex network schemes in which users self adapt to scarcity conditions. The procedure has been applied to analyse the performance of an existing supply system in Palermo (Italy). The network and users’ behaviour in intermittent distribution conditions have been monitored in order to calibrate the model and verify the reliability of the p…