2,752 research outputs found
Improving users’ comprehension of changes with animation and sound: an empirical assessment
Animation or sound is often used in user interfaces as an attempt to improve users' perception and comprehension of evolving situations and support them in decision-making. However, empirical data establishing their real effectiveness on the comprehension of changes are still lacking. We have carried out an experiment using four combinations of visual and auditory feedback in a split attention task. The results not only confirm that such feedback improves the perception of changes, but they also demonstrate that animation and sound used alone or combined bring major improvements on the comprehension of a changing situation. Based on these results, we propose design guidelines about the most efficient combinations to be used in user interfaces
The impact of perceptions in averting-decision models: An application of the special regressor method to drinking water choices
Individuals are commonly surveyed about their perception or assessment of risk and these variables are often used to explain individuals’ actions to protect themselves against these risks. Perceptions appear as endogenous variables in traditional theoretical averting-decision models but, quite surprisingly, endogeneity of perceived risk is not always controlled for in empirical studies. In this article, we present different models that can be useful to the practitioner when estimating binary averting-decision models featuring an endogenous discrete variable (such as risk perception). In particular we compare the traditional bivariate probit model with the special regressor model, which is less well known and relies on a different set of assumptions. In the empirical illustration using household data from Australia, Canada, and France, we study how the perceived health impacts of tap water affect a household’s decision to drink water from the tap. Individuals’ perceptions are found to be endogenous and significant for all models, but the estimated marginal effect is sensitive to the model and underlying assumptions. The special regressor appears to be a valuable alternative to the more common bivariate probit model
Improvement of the soil-crop model AZODYN under conventional, low-input and organic conditions
The use of mechanistic crop modelling, simulating the dynamics of crop N requirements and nitrogen supply from the soil and fertilizers, can provide sound advice to users. This paper describes a methodological way to improve soil-crop modeling used for N management of conventional and organic wheat
In situ CCVD synthesis of carbon nanotubes within a commercial ceramic foam
Consolidated nanocomposite foams containing a large quantity of carbon nanotubes (CNTs) within millimetre-sized pores are prepared for the first time. A commercial ceramic foam is impregnated by a 60 g L21 slurry of a (Mg(12x)(Co0.75Mo0.25)xO solid solution (x = 0.01, 0.05, 0.1 and 0.2) powder in ethanol. Three successive impregnations led to deposits several tens of mm thick, with a good coverage of the commercial-ceramic pore walls but without closing the pores. The materials were submitted to a CCVD treatment in H2–CH4 atmosphere in order to synthesise the CNTs. When using attrition-milled powders, the carbon is mostly in the form of nanofibres or disordered carbon rather than CNTs. Using non-milled powders produces a less-compact deposit
of catalytic material with a higher adherence to the walls of the ceramic foam. After CCVD, the carbon is mostly in the form of high-quality CNTs, as when using powder beds, their quantity being 2.5 times higher. The so-obtained consolidated nanocomposite materials show a multi-scale pore structuration
Endogenous Variables in Binary Choice Models
The main purpose of this article is to offer practical insights to econometricians wanting to estimate binary choice models featuring a continuous endogenous regressor. We use simulated data to investigate the performance of Lewbel’s special regressor method, an estimator that is relatively easy to implement and that relies on different identification conditions than more common control function and Maximum Likelihood estimators. Our findings confirm that the large support condition is crucial for the special regressor method to perform well and that one should be very cautious when implementing heteroscedasticity corrections and trimming since these could severely bias the final estimates
Effects of the vasoactive intestinal peptide (VIP) and related peptides on glioblastoma cell growth in vitro
The growth rate of numerous cancer cell lines is regulated in part by actions of neuropeptides of the vasoactive intestinal peptide (VIP) family, which also includes pituitary adenylate cyclase-activating peptide (PACAP), glucagon, and peptide histidine/isoleucine (PHI). The aim of this work was to investigate the effect of these peptides on the growth of the rat glioblastoma cell line C6 in vitro. We also sought to determine which binding sites were correlated with the effects observed. Proliferation studies performed by means of a CyQuant trade mark assay showed that VIP and PACAP strongly stimulated C6 cell proliferation at most of the concentrations tested, whereas PHI increased cell proliferation only when associated with VIP. Two growth hormone-releasing factor (GRF) derivatives and the VIP antagonist hybrid peptide neurotensin-VIP were able to inhibit VIP-induced cell growth stimulation, even at very low concentrations. Binding experiments carried out on intact cultured C6 cells, using 125I-labeled VIP and PACAP as tracers, revealed that the effects of the peptides on cell growth were correlated with the expression on C6 cells of polyvalent high-affinity VIP-PACAP binding sites and of a second subtype corresponding to very high-affinity VIP-selective binding species. The latter subtype, which interacted poorly with PACAP with a 10,000-fold lower affinity than VIP, might mediate the antagonist effects of neurotensin- VIP and of both GRF derivatives on VIP-induced cell growth stimulation
Carafe ou bouteille ? Le rôle de la qualité de l’environnement dans la décision du consommateur
Une part importante de la population française déclare lors d’enquêtes d’opinion ne pas boire l’eau du robinet, bien que la qualité de l’eau distribuée par ce canal fasse l’objet de contrôles sanitaires rigoureux et que le prix de l’eau en bouteille soit environ cent fois plus élevé que le prix de l’eau du robinet. On cherche alors à identifier les facteurs qui incitent les ménages à choisir l’eau du robinet comme eau de boisson. Sur un échantillon de ménages répartis sur la France entière, on montre que, outre les caractéristiques sociodémographiques (niveau de revenu, niveau d’éducation, type d’habitat), la qualité de l’environnement immédiat du ménage, mesurée ici par la qualité des eaux brutes, influence également sa décision de boire l’eau du robinet.
Carafe ou bouteille ? Le rôle de la qualité de l'environnement dans la décision du consommateur
Les cobénéfices des politiques climatiques : un concept opérant pour les négociations climat ?
International audienceThis paper analyzes the challenges related to the assessment of co-benefits of climate policies underpinned by the implementation of multi-objective policies which seek synergies between climate policies and other development objectives (poverty alleviation, employment, health etc.). The analysis highlights the increasing interest in co-benefits in the latest 5th IPCC report, in particular by integrated models. Nevertheless, the quantified evaluation of co-benefits is still confronted to several methodological limitations which reduce the scope of co-benefits, particularly at the global level. In a growing context of climate-development approaches in climate negotiations, this article insists on the need to also assess cobenefits of other policies which induce a significant part of GHG emissions. Considering climate policies focused only on Greehouse Gases emissions reduction limits the range of policy instruments to carbon taxation, tradable carbon emissions permits or dedicated mitigation and adaptation funds. This also hinders the integration of climate objectives in non-climate policies. Analyzing impacts of developmentpolicies on Green Gases emissions in the form of co-benefits requires to broaden the range of policy instruments and to take into account other drivers of emissions such as land dynamics. Including these mechanisms in integrated models therefore represents new scientific frontiers for integrated models in the coming years.Cet article 1 examine les enjeux sous-jacents à l'évaluation des cobénéfices des politiques climatiques dans le cadre de la mise en oeuvre de politiques multi-objectifs, au sein lesquelles des synergies sont recherchées entre la lutte contre le changement climatique et des objectifs de développement (emploi, santé, sortie de la pauvreté, etc.). L'analyse du cinquième rapport du groupe III du GIEC montre en effet un intérêt grandissant dans la littérature pour les évaluations quantifiées des cobénéfices, en particulier à l'aide de modèles numériques intégrés. Néanmoins, l'évaluation quantifiée à une échelle globale des cobénéfices est confrontée à des difficultés d'ordre méthodologique qui expliquent l'écart entre les pratiques des modélisateurs et la vision théorique des économistes qui repose sur l'analyse coûts-bénéfices. L'article revient enfin sur la nécessité d'élargir le champ d'investigation de l'évaluation des cobénéfices aux politiques non climatiques qui déterminent une part importante des émissions de GES, et constituent un des enjeux majeurs des approches intégrées climat-développement qui montent en puissance dans les négociations climat en cours. Abstract – Co-benefits of climate policies: a potential keystone of climate negotiations? This paper analyzes the challenges related to the assessment of co-benefits of climate policies underpinned by the implementation of multi-objective policies which seek synergies between climate policies and other development objectives (poverty alleviation, employment, health etc.). The analysis highlights the increasing interest in co-benefits in the latest 5th IPCC report, in particular by integrated models. Nevertheless, the quantified evaluation of co-benefits is still confronted to several methodological limitations which reduce the scope of co-benefits, particularly at the global level. In a growing context of climate-development approaches in climate negotiations, this article insists on the need to also assess co-benefits of other policies which induce a significant part of GHG emissions. Considering climate policies focused only on Greehouse Gases emissions reduction limits the range of policy instruments to carbon taxation, tradable carbon emissions permits or dedicated mitigation and adaptation funds. This also hinders the integration of climate objectives in non-climate policies. Analyzing impacts of development policies on Green Gases emissions in the form of co-benefits requires to broaden the range of policy instruments and to take into account other drivers of emissions such as land dynamics. Including these mechanisms in integrated models therefore represents new scientific frontiers for integrated models in the coming years
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