2,439 research outputs found
Test of the relation between travel and activities times : different representations of a demand derived from activity participation
The paper tests linear and non-linear specifications of the relationship between travel times and activity times, in 4 four French and three Swiss cities, observed at two different periods. First, following Kitamura et al. (1992), we test proportional assignment of total daily available time to activities (including transport). Second, proportionality is tested between (1) daily travel time associated with a given purpose with respect of the daily activity duration and (2) the travel time associated with the duration of the activity at destination. This last specification tests the travel time ratio proposed by Dijst and Vidakovic (2000). Third, because of the non appropriateness of the OLS method for analysing non-normally distributed duration data, we estimate travel time budgets in the duration model framework. We obtain non-linear relation between travel time and activity times. Only daily leisure time and daily travel time are fixed proportion of total daily available time. At disaggregated level, the trip duration do not show proportionality with activity duration. Leisure and shopping activities exhibit increasing and convex relation with travel time.TIME USE;TRAVEL TIME;ACTIVITY BASED ANALYSIS
Willingness to pay for environmental attributes of non-food agricultural products: a real choice experiment
This paper investigates consumersâ willingness to pay (WTP) a price premium for two environmental attributes of a non-food agricultural product. We study individual preferences for roses associated with an eco-label and a carbon footprint using an economic experiment combining discrete choice questions and real economic incentives involving real purchases of roses against cash. The data are analyzed with a mixed logit model and reveal significant premiums for both environmental attributes of the product.WILLINGNESS TO PAY;ENVIRONMENTAL ATTRIBUTES;NON-FOOD PRODUCT;REAL CHOICE EXPERIMENT;MIXED LOGIT
Raisons et pratiques de la pendularité intensive : le temps de trajet, entre temps subi et temps choisi
Cet article Ă©tudie les raisons conduisant certains individus Ă consacrer des temps importants Ă leur mobilitĂ©, par une approche mixte, en mobilisant les mĂ©thodologies quantitatives et qualitatives. Dans la littĂ©rature, le temps de trajet est traditionnellement considĂ©rĂ© comme un temps inutile et non-productif, voire comme le pire temps de la journĂ©e. Dans ces conditions, le comportement des pendulaires intensifs qui passent plus de deux heures quotidiennes Ă se dĂ©placer, constitue sinon une remise en question, du moins un contre-exemple Ă cette conception du temps de trajet. Tout d'abord, une analyse quantitative des budgets-temps de transport (BTT) dans huit villes (Berne, Bruxelles, GenĂšve, Grenoble, Lyon, Rennes, Strasbourg et Zurich) explore les temps de transport dans ces villes par la mĂ©thode des modĂšles de durĂ©es. Un premier rĂ©sultat est quâenviron 20% des individus de l'Ă©chantillon de chaque ville font face Ă des dĂ©placements de longue durĂ©e (plus de 100 minutes). Ensuite, le modĂšle de durĂ©es estimĂ© suggĂšre un comportement atypique de ces individus, qui nâest pas explicable uniquement par leurs caractĂ©ristiques renseignĂ©es dans les enquĂȘtes de mobilitĂ©s.Ensuite, les rĂ©sultats des entretiens qualitatifs dâindividus, dont les BTT sont supĂ©rieurs Ă deux heures sont prĂ©sentĂ©s. Diverses dimensions illustrent les choix ou les obligations qui causent ces BTT extrĂȘmes. Lâapproche sociologique qualitative complĂšte lâapproche Ă©conomĂ©trique quantitative et illustre que lâallocation de temps au transport nâest pas uniquement dĂ©terminĂ©e par lâactivitĂ© Ă destination et les modes de transport, mais aussi par dâautres Ă©lĂ©ments tels que les convictions personnelles, les interactions avec les autres membres du mĂ©nage, la perception de ce temps de transport, etc. Notamment, le temps de transport peut ĂȘtre perçu comme un temps support dâautres activitĂ©s (ex. travailler, Ă©couter de la musique, etc.).TEMPS DE TRANSPORT;PENDULARITE;APPROPRIATION DES TEMPS DE TRANSPORT;MODELE DE SURVIE;APPROCHE MIXTE
Liquid friction on charged surfaces: from hydrodynamic slippage to electrokinetics
Hydrodynamic behavior at the vicinity of a confining wall is closely related
to the friction properties of the liquid/solid interface. Here we consider,
using Molecular Dynamics simulations, the electric contribution to friction for
charged surfaces, and the induced modification of the hydrodynamic boundary
condition at the confining boundary. The consequences of liquid slippage for
electrokinetic phenomena, through the coupling between hydrodynamics and
electrostatics within the electric double layer, are explored. Strong
amplification of electro-osmotic effects is revealed, and the non-trivial
effect of surface charge is discussed. This work allows to reconsider existing
experimental data, concerning Zeta potentials of hydrophobic surfaces and
suggest the possibility to generate ``giant'' electro-osmotic and
electrophoretic effects, with direct applications in microfluidics
Le niveau de comprĂ©hension de lâanglais des Ă©tudiants en mĂ©decine peut ĂȘtre amĂ©liorĂ©. RĂ©sultats dâune stratĂ©gie dâĂ©valuation systĂ©matique
Objectives
To describe the level of English of a population of medical students and the improvement after the implementation of systematic assessment that all students achieve a minimal level.
Population and methods
For the past 5Â years, all medical students in our medical school have been taking the Test of English for International Communication (TOEIC). The baseline population (students entering second year in 2004) had no specific obligation. After 2004, a score above 600 was mandatory for graduation. Teaching was oriented towards training for the TOEIC and the number of hours was more important for low-level students.
Results
The mean score has increased from 618 ± 146 in 2004, to 687 ± 94, 717 ± 97, 733 ± 96 and 731 ± 104 for the next four years. The proportion of students who do not achieve a score of 550 (B1 level of the European framework) has decreased from 30 to 0%.
Discussion
Improving the level of English of French medical students is possible, if this is made a priority. The objective, as set in engineering studies, that all medical students reach a B2 level would require national guidelines
Evaluation dâune procĂ©dure de recherche rĂ©trospective des infections du site opĂ©ratoire au Centre Hospitalier Universitaire dâAngers
National audienc
De la longévité coopérative: une étude de la dynamique des coopératives agricoles françaises
Le paysage coopératif agricole est en forte transformation depuis de nombreuses années, entre disparitions, fusions et consolidations. Différents travaux théoriques ont tenté de proposer une explication des particularités coopératives en termes d\u27efficacité et de capacité à survivre. Nous en présentons ici les grandes propositions de recherche. Notre travail est centré sur une contribution empirique. A ce titre, la mobilisation de méthodes simples d\u27analyse de survie permet de mettre en évidence une dynamique temporelle favorable aux coopératives vis-à -vis des autres entreprises avec lesquelles elles sont en concurrence. Cette dynamique s\u27accompagne de trajectoires sectorielles particuliÚres et de dynamiques spécifiques suivant les régions. En conclusion, nous proposons quelques pistes d\u27explication de ces dynamiques
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