4,044 research outputs found

    Effect of anisotropy on the onset of convection in rotating bi-disperse Brinkman porous media

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    AbstractThermal convection in a horizontally isotropic bi-disperse porous medium (BDPM) uniformly heated from below is analysed. The combined effects of uniform vertical rotation and Brinkman law on the stability of the steady state of the momentum equations in a BDPM are investigated. Linear and nonlinear stability analysis of the conduction solution is performed, and the coincidence between linear instability and nonlinear stability thresholds in theL2L^2L2-norm is obtained

    Hub-and-Spoke or else? Free trade agreements in the 'enlarged' European Union

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    The object of this paper is to estimate if and how the Central European Free Trade Agreement (CEFTA) and the Baltic Free Trade Agreement (BFTA) exerted a significant impact on intra-European trade, effectively reducing the influence of the European Association Agreements (EAs) in shaping the European trade structure as a hub-and-spoke system - with the EU15 being the hub and the CEECs the spoke. This paper analyses bilateral trade flows between eight CEECs and EU-23. We estimate a gravity equation using a system GMM dynamic panel data approach. Results support the assumptions that gravity forces and "persistence effects" matter. With respect to the effect of free trade agreements, evidence is found that Free trade agreements between CEECs matter: There is evidence that the presence of intra-periphery agreements helped expand intra-periphery trade and limited the emergence of a "hub-and-spoke" relationship between CEECs and EU. This results have important policy implications for the trade strategy of "future" EU members of the Southeastern European Countries as well as of the Southern Mediterranean Countries. According to the empirical results, these countries should move towards a regional free-trade area as exemplified by the CEFTA and the BFTA to avoid "hub-and-spoke" effects.Trade flows, regional integration, EU eastward enlargement, gravity model, dynamic panel data

    Psychosocial Training: A Case of Self-Efficacy Improvement in an Italian School

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    The changes that the regulatory institutions have imposed on the Italian school system over the last decades may actually result in contradictory effects at the individual and organizational levels: resistance or indifference on the one hand and training or coping strategies on the other. The paper focuses on the impact of such changes on teachers, as professional workers within public schools and individual participants of change. The paper refers to psychosocial training as a coping strategy, analysing how school teachers deal with work-related stress, and what impact a training intervention might have on some individual dimensions. Subsequently, in the longitudinal study presented, we analysed whether the training intervention conducted was effective in terms of learning and change. The case under consideration is a primary school located in the South of Italy, and the participants in the training and research were 92 female teachers. In order to investigate the effectiveness of the designed and applied training programme, we measured how some important psychological dimensions have changed over time: self-efficacy, job satisfaction and interpersonal strain. According to a sociological learning approach, the results suggest the effectiveness of training programmes as enablers of change and solutions to some change paradoxes; when they respond to the identified needs, they are based on practical activities that require a collective participation, they focus on social relationships and processes and the knowledge is created through the transformation of experience. In the school context, the psychosocial training might represent a solution, if not a prevention strategy, for change management

    Engaging Public Servants: Public Service Motivation, Work Engagement and Work-Related Stress

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    Considering the ongoing international debate on the role of public administrations in economic systems, public service motivation (PSM) has significantly and increasingly attracted the attention of practitioners and scholars in the past two decades. Following the research streams that have investigated topics of organizational behavior in the public context, this study examines the influence of PSM on the feeling of job satisfaction for public employees. The novelty of the study lies in linking some features of the work context considered to be more prevalent in public organizations with specific job characteristics, seen as determinant antecedents of job satisfaction. Based on two complementary studies conducted in an Italian public administration, this paper shows how PSM influences job satisfaction, job engagement, and life satisfaction. Additionally, the findings display how job engagement affects both job and life satisfaction in these particular contexts. Furthermore, the paper sheds new light on how to deal with such problems and at the same time opens new avenues for investigation

    Analysis of a model for waterborne diseases with Allee effect on bacteria

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    A limitation of current modeling studies in waterborne diseases (one of the leading causes of death worldwide) is that the intrinsic dynamics of the pathogens is poorly addressed, leading to incomplete, and often, inadequate understanding of the pathogen evolution and its impact on disease transmission and spread. To overcome these limitations, in this paper, we consider an ODEs model with bacterial growth inducing Allee effect. We adopt an adequate functional response to significantly express the shape of indirect transmission. The existence and stability of biologically meaningful equilibria is investigated through a detailed discussion of both backward and Hopf bifurcations. The sensitivity analysis of the basic reproduction number is performed. Numerical simulations confirming the obtained results in two different scenarios are shown

    Estimating an Injury Crash Rate Prediction Model based on severity levels evaluation: The case study of single-vehicle run-off-road crashes on rural context

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    Abstract In general in case of crash situations the quality of collected data is very limited and several information are usually unreliable. Thus it is recognised that a significant effort is required in order to improve the quality of the crash prediction models moreover a crucial role is played by the identification of the factors influencing the crashes occurrence and the levels of severity estimation. In this paper two injury crash rate prediction models related to single-vehicle run-off-road crashes type are calibrated and in particular significant attributes estimated are identified not only with roadway geometric characteristics and surface conditions, but also with gender/number-of-drivers. To this aim a survey of injury crashes on two-lane rural roads collected in the Southern Italy was considered and analysed. Finally before the calibration step, a preliminary analysis of the data was provided through the estimation of the levels of severity by multinomial logit; in fact by this model only segments with highest values of severity are identified and involved in the calibration procedure

    Gene expression in mdx mouse muscle in relation to age and exercise: aberrant mechanical-metabolic coupling and implications for pre-clinical studies in duchenne muscular dystrophy

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    Weakness and fatigability are typical features of Duchenne muscular dystrophy patients and are aggravated in dystrophic mdx mice by chronic treadmill exercise. Mechanical activity modulates gene expression and muscle plasticity. Here, we investigated the outcome of 4 (T4, 8 weeks of age) and 12 (T12, 16 weeks of age) weeks of either exercise or cage-based activity on a large set of genes in the gastrocnemius muscle of mdx and wild-type (WT) mice using quantitative real-time PCR. Basal expression of the exercise-sensitive genes peroxisome-proliferator receptor γ coactivator 1α (Pgc-1α) and Sirtuin1 (Sirt1) was higher in mdx versus WT mice at both ages. Exercise increased Pgc-1α expression in WT mice; Pgc-1α was downregulated by T12 exercise in mdx muscles, along with Sirt1, Pparγ and the autophagy marker Bnip3. Sixteen weeks old mdx mice showed a basal overexpression of the slow Mhc1 isoform and Serca2; T12 exercise fully contrasted this basal adaptation as well as the high expression of follistatin and myogenin. Conversely, T12 exercise was ineffective in WT mice. Damage-related genes such as gp91-phox (NADPH-oxidase2), Tgfβ, Tnfα and c-Src tyrosine kinase were overexpressed in mdx muscles and not affected by exercise. Likewise, the anti-inflammatory adiponectin was lower in T12-exercised mdx muscles. Chronic exercise with minor adaptive effects in WT muscles leads to maladaptation in mdx muscles with a disequilibrium between protective and damaging signals. Increased understanding of the pathways involved in the altered mechanical-metabolic coupling may help guide appropriate physical therapies while better addressing pharmacological interventions in translational researchWeakness and fatigability are typical features of Duchenne muscular dystrophy patients and are aggravated in dystrophic mdx mice by chronic treadmill exercise. Mechanical activity modulates gene expression and muscle plasticity. Here, we investigated the outcome of 4 (T4, 8 weeks of age) and 12 (T12, 16 weeks of age) weeks of either exercise or cage-based activity on a large set of genes in the gastrocnemius muscle of mdx and wildtype (WT) mice using quantitative real-time PCR. Basal expression of the exercise-sensitive genes peroxisome-proliferator receptor g coactivator 1α (Pgc-1α) and Sirtuin1 (Sirt1) was higher in mdx versus WT mice at both ages. Exercise increased Pgc-1α expression in WT mice; Pgc-1α was downregulted by T12 exercise in mdx muscles, along with Sirt1, Pparγ and the autophagy marker Bnip3. Sixteen weeks old mdx mice showed a basal over expression of the slowMhc1 isoform and Serca2; T12 exercise fully contrasted this basal adaptation as well as the high expression of follistatin and myogenin. Conversely, T12 exercise was ineffective in WT mice. Damage-related genes such as gp91-phox (NADPH-oxidase2), Tgfβ, Tnfα and c-Src tyrosine kinase were overexpressed in mdx muscles and not affected by exercise. Likewise, the anti-inflammatory adiponectin was lower in T12-exercised mdx muscles. Chronic exercise with minor adaptive effects in WT muscles leads to maladaptation in mdx muscles with a disequilibrium between protective and damaging signals. Increased understanding of the pathways involved in the altered mechanical-metabolic coupling may help guide appropriate physical therapies while better addressing pharmacological interventions in translational research

    Favouring behavioural change of household’s energy consumption through social media and cooperative play

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    A change in how individuals consume energy is a key step in fighting climate change since it represents a crucial contribution to a more collective and sustainable lifestyle adoption. To carry out such process, designers and scientists are seeking new ways to increase public discussion and social involvement in energy reduction issues. In relation to this, the emphasis is on raising collective awareness to enable behavioural change and to inspire people in making sustainable decisions on energy consumption. This article draws on techniques and approaches from social science, gameful design and sustainability. It defines and discusses cooperative play as a privileged path for developing energy-related mobile applications. We present here an overview of multiple perspectives, in terms of content and methodology, to contribute to elaborating design methodologies that can favour behavioural change on households’ energy consumption
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