Search results for "Processes"
showing 10 items of 3831 documents
A stochastic reaction-diffusion-taxis model for two picophytoplankton populations
2012
In this work, the stationary distributions of two populations of picophytoplankton, i.e. picoeukaryotes and Prochlorococcus, are studied. This two groups account on average for 60% of the total chlorophyll a (chl a) and divinil chlorophyll a (divinil chl a) concentration in Mediterranean Sea. The interaction of these populations with the environment occurs through two factors that limit the growth of the aquatic microorganisms: light intensity and nutrient, i.e. phosphorus. The dynamics of the two picophytoplanktonic groups, distributed at different depth along a water column (one-dimensional spatial domain), is analyzed starting from a deterministic reaction-diffusion-taxis model. This con…
Examination of Goal Orientation, Sense of Coherence, and Motivational Climate as predictors of Perceived Physical Competence
2010
The purpose of the present study was to investigate the extent to which children's goal orientation, sense of coherence (SOC), and perceptions of the motivational climate in PE accounted for their perceived physical competence. The variable measures were conducted with the participants (382 boys, 389 girls), aged 15-16, who completed a set of self-reported questionnaires. The hierarchical multiple-regression results showed that all steps lead to significant change in the models and accounted for 20.2 % of the variance in perceived physical competence. More specifically, the inclusion of task and ego orientation resulted in an additional 11.4 % of explained variance and the inclusion of SOC …
Gap Filling of Biophysical Parameter Time Series with Multi-Output Gaussian Processes
2018
In this work we evaluate multi-output (MO) Gaussian Process (GP) models based on the linear model of coregionalization (LMC) for estimation of biophysical parameter variables under a gap filling setup. In particular, we focus on LAI and fAPAR over rice areas. We show how this problem cannot be solved with standard single-output (SO) GP models, and how the proposed MO-GP models are able to successfully predict these variables even in high missing data regimes, by implicitly performing an across-domain information transfer. CICYT TIN2015-64210-R In this work we evaluate multi-output (MO) Gaussian Process (GP) models based on the linear model of coregionalization (LMC) for estimation of biophy…
Dynamics of a quantum particle interacting with a thermal bath and subject to an oscillating asymmetric bistable potential
2012
Exploiting the approach of the Feynman-Vernon influence functional [1] within the framework of the discrete variable representation (DVR) [2], we consider a quantum particle described by the Caldeira-Leggett model [3]. The particle, “moving” in an asymmetric bistable potential and subject to a periodical driving, interacts with a thermal bath of harmonic oscillators. In this conditions we study the dynamics of the particle by analyzing the time evolution of the populations in the DVR. Specifically we focalize on the position eigenstate located in the shallower well, i.e. metastable state, finding a non-monotonic behaviour of the corresponding population as a function of the frequency. Moreo…
A stochastic reaction-diffusion-taxis model for picophytoplankton dynamics
2011
The dynamics of picophytoplankton communities in marine environment is studied by astochastic reaction-dìffusìon-taxis model, analyzing the time evolution of the biomass concentration along a water column. The model is based on two stochastic differentìal equations, where the random fluctuations of the environmental variables are considered by inserting two multiplicative noise terms. Specifically, the model describes the dynamics of diffusion of picophytoplankton biomass and nutrient concentrations. In the proposed model the marine environment is characterized by poorly mixed waters and picophytoplankton is subject to intraspecific competition for light and nutrients. By numerically solvin…
New Trends in Urban Drainage Modelling
2019
This book addresses the latest research advances, innovations, and applications in the field of urban drainage and water management as presented by leading researchers, scientists and practitioners from around the world at the 11th International Conference on Urban Drainage Modelling (UDM), held in Palermo, Italy from 23 to 26 September, 2018. The conference was promoted and organized by the University of Palermo, Italy and the International Working Group on Data and Models, with the support of four of the world’s leading organizations in the water sector: the International Water Association (IWA), International Association for Hydro-Environment Engineering and Research (IAHR), Environmenta…
Transient Dynamics of a Driven Quantum Bistable System
2013
We study the transient dynamics and the asymptotic behaviour of a multilevel system in the strong dissipation regime. The system is modeled as a periodically driven quantum particle in an asymmetric double well potential, interacting with the bosonic heat bath of the Caldeira-Leggett model. The analytical approach used is non- perturbative in the particle-bath coupling and is based on a space-discretized path integral expression for the particle’s reduced density matrix. By a suitable approximation on the Feynman-Vernon influence functional a Markov-approximated master equation is obtained for the populations in the Discrete Variable Representation (DVR).
Influence of Musical Context on the Perception of Emotional Expression of Music
2013
Factors determining and influencing the perception of emotional expression of music include those related to music itself, to the listener, and to the context. Among the latter there is also music, as we rarely listen to a single piece. A simple experimental study has been carried out into the effect of music listened to immediately beforehand on the perception of the emotional expression of a musical piece. The following variables were involved: type of emotional expression of music conceived in terms of a most basic sad-joyful dimension, initial and final mood of the listeners, their professional musical education vs. lack thereof, age, and gender. The subjects were students of three age …
Grappling with the Oral Skills: The learning processes of the low-educated adult second language and literacy learner
2013
This paper focuses on the learning processes in L2 literacy classes in the Netherlands, discussing specifically possible influences of the learning processes during the practice of the oral skills. To achieve a better understanding of the students’ spoken language development, classroom processes of six adult L2 literacy classes were observed during a period of eight months and students were pre- and post-assessed. In comparing the classes, notable differences in gain scores in morphosyntactic features as well as aspects of relevance and coherence in discourse surfaced. In order to explain these differences, certain factors were examined in relation to learner characteristics, classro…
Stochastic resonance effect on the vibratory signals of stink bugs
2007
In this work we investigate the role of the environmental noise in the sexual communication between individuals of the Sicilian green stink bug Nezara Viridula. Our goal is to analyze the spectral features of several types of songs emitted by these insects and to find the amplitude threshold value. Below this value the signal is so weak that no neuronal activation occurs in Nezara Viridula. The presence of activation is revealed by performing directionality tests and observing the behavioral response of the insect in localizing the source of vibratory signals. Afterwards experiments are performed by using a sub-threshold signal added to a white Gaussian noise. The response of the test insec…