1,721,114 research outputs found
Diffusive processes in systems with geometrical constraints: from lattice models to continuous channels
Full text linkWe focus on the Brownian motion within channels with varying cross – section as well
as on the diffusion on branched structures, a subject particularly relevant for the
modeling of the passive transport process within living cells, which are characterized
by a naturally constrained environment and the motion, at least on the length scales
of the macromolecules, is well described by diffusion rather than bulk flow. In
particular, we studied the occurrence of anomalous transport in a variety of branched
structures and fractal trees. We proved that the Fluctuation Dissipation Relation
(FDR) can be extended, in some cases, to the anomalous transport regime, at least
within the linear response approximation. On the other hand, We pointed out how the
FDR can be broken by choosing properly the branching of the analyzed structure, as a
consequence of the emergence of an “entropic” drift due to the high ramifications
introduced. This result suggests that FDRs are more sensitive to the geometrical
structure rather than to the details of the dynamics. We also analyzed, in contrast to
those examples showing anomalous diffusion, a series of situations characterized by a
standard scaling of the MSD (and/or of the higher order moments), however with a
non Gaussian probability density, thus showing how standard diffusion is not always
Gaussian
Sistemi di accumulo per la gestione degli impianti eolici
No full textL’integrazione nel sistema elettrico di impianti a fonti rinnovabili non programmabili è vincolata al rispetto di regole tecniche operative. I sistemi di accumulo, opportunamente abbinati con questi impianti, possono essere utilizzati per un’efficiente programmazione oraria della produzion
L’attività del sistema nervoso autonomo durante un falso ricordo: una revisione sistematica della letteratura
No full textTransport and fluctuation-dissipation relations in asymptotic and preasymptotic diffusion across channels with variable section
No full textLa fattibilità economica del nucleare nel mercato elettrico italiano
No full textIn questo lavoro si effettua un’analisi finanziaria con l’obiettivo di determinare la convenienza economica dell’investimento nella produzione di energia elettrica da fonte nucleare all’interno del mercato elettrico italiano. A tal fine, sono valutate le varie voci di costo di un impianto tipo con tecnologia European Pressurized Reactor (EPR) tenendo conto di due possibili scenari, caratterizzati da differenti modalità di finanziamento. Sono inoltre effettuate simulazioni di mercato per 40 anni in presenza di impianti nucleari al fine di valutare l’impatto sui prezzi e sulla redditività
Wind farm stability analysis in the presence of variable-speed generators
No full textVariable-speed technologies have been adopted to improve the efficiency of electricity generation in wind farms. Among these technologies, doubly-fed induction generators have widely spread and their stability issues have been experienced and analysed. In recent years, permanent-magnet synchronous generators have been also exploited, connected to the grid through full-scale converters, ensuring high flexibility, reducing losses and weight. The presence of these technologies heightens the necessity of deeply investigating wind turbine behaviour under different disturbances.
In this paper, a small- and large-disturbance stability analysis is carried out in order to compare dynamic characteristic of wind farm equipped with the aforementioned generation technologies. To this purpose, a detailed model of wind turbine, together with relevant control schemes, is adopted for each generator of a real-sized wind farm. The compliance of the plant with fault-ride-through requirements imposed by transmission system operator is also verified
Executive Functions: a relevant feature of cognitive decline. Clinical impact of experimental evidence
No full textBoth physiological and pathological decline in aging is characterized by a loss of cognitive functioning from mild to severe. This decline involves many cognitive domains, and it is characterized by memory difficulties, poor mental flexibility, lower ability to inhibit responses and appropriately respond to environmental stim- uli. According to its severity, cognitive decline can affect daily life activities. However, in the classification of Mild Cognitive Decline (MCD), low attentional focus in the clinical field was directed toward executive functioning, a cognitive domain highly relevant for goal-directed behaviors and positive daily functioning. Analyzing the main features of executive functioning in MCD and the main differences from healthy to pathological aging can help define the impaired trend of functioning, which affects decline. Clinicians should consider including executive functioning in the diagnostic classification of MCD. This new classification would be useful for developing novelty treatments focused on enhancing this domain to reduce the impact on the daily life of elderly people. Experimental evidence on executive functioning in MCI may clarify these aspects
A model to understand risk behavior: interoception awareness and motivational systems in the binge watching
No full textThis study aims to test the interoceptive-motivational hypothesis as a possible marker for the risk
of developing binge-watching (BW) as a behavioral addiction. Like other risky behaviors, BW can
be included in a model that includes the interaction of personological and physiological factors as
predictors of the behavioral outcome. On a sample of 741 young adults, a structural equation
model considered the association between the interoceptive indices (MAIA questionnaire), inhi
bition/activation systems (BIS/BAS questionnaire) of the motivational theory, and BW pattern
(BWAQ questionnaire). The results suggested a different interaction between the variables when
BW was considered as a leisure activity and as an at-risk behavior. While in the first case,
interoception and BIS/BAS systems interact, and BIS and interoception positively affect the in
crease of BW as a leisure activity, in BW as at-risk behavior, the interoceptive-motivational link is
lost, and a different pattern of association with the behavior emerges. BIS and BW are still
positively associated with the problematic expression of the behavior. The result would suggest
that persons exhibiting better interoceptive sensitivity display lower risk of addictive BW. Finally,
the interoceptive-motivational model, if confirmed in other at-risk behaviors, would provide a
new perspective in the field of behavioral addictions
The instinct to eat: the role of autonomic nervous system in influencing executive response toward food stimuli.
No full textThe current society, characterized by a food-abundant environment may contribute to the tendency to overeat and weight gain. Previous research confirms an altered attentional response towards food stimuli which can influence dysregulated eating behavior via executive functions. The Neurovisceral Integration Model, proposing a role of the integration between biological and cognitive systems in the environmental adaptation of the organism. It may indicate a role of the autonomic response (via heart rate variability; HRV) in influencing executive response toward food stimuli.
One-hundred and twenty young adults (age range: 18-30 years) participated at the study. The 26 percent of the sample presented overweight condition. All the participants completed modified version of the Stroop task with food stimuli (hypercaloric and hypocaloric). HRV was recorded in resting (5 minutes), reactivity (during the task) and recovery (3 minutes). No differences emerged between overweight and normal weight condition in HRV indices (p> 0.05). However, a mediator role of HRV was reported in the association between executive performances and weight condition, particularly in case of hypercaloric food stimuli. These preliminary results support the evidence of a mediator role of autonomic system in influencing executive response toward food stimuli in general population
Planning and Operating Combined Wind-Storage System in Electricity Market
No full textThe increasing penetration of renewable sources in power systems yields various issues in network operation. Most of them are related to uncertainties of energy production. In particular, the variability of wind source does not allow for accurate forecasting of power generation. Production plans may not be accomplished, incurring penalties for system unbalance. For this reason, the use of an energy storage system can improve integration of wind energy in production planning and dispatch. In this paper, an approach for planning and operating an energy storage system for a wind farm in the electricity market is proposed. To this purpose, electrochemical batteries are employed to compensate for generation variations in order to set up a reliable hourly delivery profile, complying with market requirements. The delivery plan can be settled according to energy prices, as well. Moreover, an economic feasibility analysis is carried out on the combined wind-storage system
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