Determinants of travel mode choice in Europe: Results from a survey on routine mobility

Understanding the differences in travel behaviour across different countries underlined by trip and individual characteristics are paramount to develop effective policies to nudge a shift towards sustainable mobility. In this study we present a descriptive analysis of the results of a mobility household survey, collecting information on citizen travel behaviour, travel mode choices and the factors influencing them. The study involves five European countries: Hungary, Italy, Norway, Poland and Spain. Results describe how travel mode choice fluctuates with users’ heterogeneity and that different mobility transition policies receive different support from citizens. Instruments implying a direct financial cost are much less accepted than technology- and infrastructure-based policies. Support to policies such as road expansion is also observed. The transition in mobility should then have to deal with households’ beliefs to make them revise their travel behaviours. But the mobility transition is also closely linked to the city development and the distribution of workplace and grocery shopping in the cit

Influenza della risposta sismica locale sul non sincronismo del moto in superficie: validazione empirica delle indicazioni normative

Nella progettazione di opere con significativo sviluppo longitudinale delle fondazioni, il moto sismico può avere caratteristiche variabili lungo lo sviluppo della struttura. Le differenze possono essere causate dalla perdita di sincronismo nella propagazione delle onde, dalle disomogeneità e discontinuità del sottosuolo e dalla diversa risposta locale del terreno. Secondo le prescrizioni delle Norme Tecniche per le Costruzioni (D.M. 14/1/2008), la valutazione degli effetti del moto asincrono indotti sulle strutture può essere effettuata combinando gli effetti dinamici con quelli pseudo-statici causati dallo spostamento relativo massimo tra due punti della struttura. Questi ultimi si possono valutare attraverso una relazione che deriva dalla soluzione di un modello analitico di propagazione delle onde sismiche (Nuti & Vanzi, 2005). Obiettivo di questo studio è verificare le regole presenti nelle NTC attraverso il confronto con valori di spostamento relativo derivanti da registrazioni accelerometriche di eventi sismici reali. L’effetto combinato dei fattori sopra menzionati è stato valutato empiricamente attraverso l’analisi del moto sismico in superficie registrato da coppie di stazioni ac-celerometriche, ubicate a distanze dell’ordine delle centinaia di metri, su terreni con caratteristiche lito-stratigrafiche corrispondenti ad un sito di riferimento (classe A della Normativa) e un sito con amplificazio-ne stratigrafica (classi B, C, D). Gli spostamenti relativi, calcolati secondo tre possibili approcci, mostrano che la formulazione analitica suggerita dalla Normativa è appropriata per descrivere la dipendenza degli spo-stamenti relativi dall’accelerazione di riferimento. Gli spostamenti calcolati secondo le prescrizioni di Nor-mativa, inoltre, risultano mediamente maggiori di quelli misurati sperimentalmente

Is the Vlasov equation valid for Yukawa plasmas?

We analyze the Vlasov dispersion relation for Yukawa plasmas in three dimensions for the purpose of identifying coupling parameter domains where the Vlasov approach is justified and the existence of a well-developed RPA type collective excitation is allowed. We establish a rigorous lower bound for the coupling parameter, below which there can be no real solution to the Vlasov dispersion relation. In the coupling domain, where weakly damped solutions do exist, we have focused on the long-wavelength acoustic regime where we establish more restrictive estimates for the lower bound of the coupling parameter. We also derive a general formula for the corresponding acoustic phase velocity, valid over a wide range of coupling parameter/screening parameter ratios above the lower bound. We conclude that the Vlasov approach is tenable only above a critical coupling value. Comparison with Molecular Dynamics simulation results further highlights the limitations of the Vlasov approximation for weakly coupled Yukawa plasmas

Collective behaviour without collective order in wild swarms of midges

Collective behaviour is a widespread phenomenon in biology, cutting through a huge span of scales, from cell colonies up to bird flocks and fish schools. The most prominent trait of collective behaviour is the emergence of global order: individuals synchronize their states, giving the stunning impression that the group behaves as one. In many biological systems, though, it is unclear whether global order is present. A paradigmatic case is that of insect swarms, whose erratic movements seem to suggest that group formation is a mere epiphenomenon of the independent interaction of each individual with an external landmark. In these cases, whether or not the group behaves truly collectively is debated. Here, we experimentally study swarms of midges in the field and measure how much the change of direction of one midge affects that of other individuals. We discover that, despite the lack of collective order, swarms display very strong correlations, totally incompatible with models of noninteracting particles. We find that correlation increases sharply with the swarm's density, indicating that the interaction between midges is based on a metric perception mechanism. By means of numerical simulations we demonstrate that such growing correlation is typical of a system close to an ordering transition. Our findings suggest that correlation, rather than order, is the true hallmark of collective behaviour in biological systems.Comment: The original version has been split into two parts. This first part focuses on order vs. correlation. The second part, about finite-size scaling, will be included in a separate paper. 15 pages, 6 figures, 1 table, 5 video

Finite-size scaling as a way to probe near-criticality in natural swarms

Collective behaviour in biological systems is often accompanied by strong correlations. The question has therefore arisen of whether correlation is amplified by the vicinity to some critical point in the parameters space. Biological systems, though, are typically quite far from the thermodynamic limit, so that the value of the control parameter at which correlation and susceptibility peak depend on size. Hence, a system would need to readjust its control parameter according to its size in order to be maximally correlated. This readjustment, though, has never been observed experimentally. By gathering three-dimensional data on swarms of midges in the field we find that swarms tune their control parameter and size so as to maintain a scaling behaviour of the correlation function. As a consequence, correlation length and susceptibility scale with the system's size and swarms exhibit a near-maximal degree of correlation at all sizes.Comment: Selected for Viewpoint in Physics; PRL Editor's Suggestio

La transición a la cultura universitaria en la interpretación y las vivencias de estudiantes de Ciencias de la Educación

Este trabajo informa resultados de una investigación dedicada a examinar la perspectiva de estudiantes de Ciencias de la Educación con un año de permanencia en la carrera, sobre cuestiones relacionadas con la transición del nivel medio a la universidad. Centramos el análisis en sus apreciaciones acerca de las modificaciones en la frecuencia de uso de las estrategias empleadas en la universidad y en la escuela, las dificultades en la vida académica y las condiciones de estudio y aprendizaje en cada contexto. Treinta y cuatro estudiantes respondieron un cuestionario estructurado, y quince de ellos participaron en entrevistas. Los procesos de autorregulación revelan una importancia decisiva, tanto por tratarse de las estrategias mayormente desarrolladas en la facultad, como por constituir lo propio del estudio en el nivel superior, especialmente en cuanto al logro de autonomía, la organización del tiempo y la regulación del esfuerzo. Consistentemente, las principales dificultades corresponden a la ausencia de un hábito de estudio ajustado a las nuevas exigencias, lo cual compromete el desempeño académico en la asistencia a clases, la lectura de textos, la constancia, el tiempo de estudio y la preparación de exámenes. La experiencia adquirida durante el tiempo de afiliación y aprendizaje que supone el primer año, ha posibilitado una amplia comprensión de aquello que es indispensable asumir y comprometer en la actuación académica para aspirar a la permanencia exitosa en el sistema de educación superior, lo cual no implica necesariamente que en la práctica los estudiantes pueda actuar conforme a esa comprensión de modo sostenido.</p

La transición a la cultura universitaria en la interpretación y las vivencias de estudiantes de Ciencias de la Educación

Este trabajo informa resultados de una investigación dedicada a examinar la perspectiva de estudiantes de Ciencias de la Educación con un año de permanencia en la carrera, sobre cuestiones relacionadas con la transición del nivel medio a la universidad. Centramos el análisis en sus apreciaciones acerca de las modificaciones en la frecuencia de uso de las estrategias empleadas en la universidad y en la escuela, las dificultades en la vida académica y las condiciones de estudio y aprendizaje en cada contexto. Treinta y cuatro estudiantes respondieron un cuestionario estructurado, y quince de ellos participaron en entrevistas. Los procesos de autorregulación revelan una importancia decisiva, tanto por tratarse de las estrategias mayormente desarrolladas en la facultad, como por constituir lo propio del estudio en el nivel superior, especialmente en cuanto al logro de autonomía, la organización del tiempo y la regulación del esfuerzo. Consistentemente, las principales dificultades corresponden a la ausencia de un hábito de estudio ajustado a las nuevas exigencias, lo cual compromete el desempeño académico en la asistencia a clases, la lectura de textos, la constancia, el tiempo de estudio y la preparación de exámenes. La experiencia adquirida durante el tiempo de afiliación y aprendizaje que supone el primer año, ha posibilitado una amplia comprensión de aquello que es indispensable asumir y comprometer en la actuación académica para aspirar a la permanencia exitosa en el sistema de educación superior, lo cual no implica necesariamente que en la práctica los estudiantes pueda actuar conforme a esa comprensión de modo sostenido

Differential effects on membrane permeability and viability of human keratinocyte cells undergoing very low intensity megasonic fields

Among different therapeutic applications of Ultrasound (US), transient membrane sonoporation (SP) - a temporary, non-lethal porosity, mechanically induced in cell membranes through US exposure - represents a compelling opportunity towards an efficient and safe drug delivery. Nevertheless, progresses in this field have been limited by an insufficient understanding of the potential cytotoxic effects of US related to the failure of the cellular repair and to the possible activation of inflammatory pathway. In this framework we studied the in vitro effects of very low-intensity US on a human keratinocyte cell line, which represents an ideal model system of skin protective barrier cells which are the first to be involved during medical US treatments. Bioeffects linked to US application at 1 MHz varying the exposure parameters were investigated by fluorescence microscopy and fluorescence activated cell sorting. Our results indicate that keratinocytes undergoing low US doses can uptake drug model molecules with size and efficiency which depend on exposure parameters. According to sub-cavitation SP models, we have identified the range of doses triggering transient membrane SP, actually with negligible biological damage. By increasing US doses we observed a reduced cells viability and an inflammatory gene overexpression enlightening novel healthy relevant strategies