Error propagation through a bayesian network for biomass estimation in neotropical forests

The above-ground biomass (AGB) of tropical forests is a crucial variable for the global ecological problems. It concerns both scientists and decision makers, especially through the recently set carbon market. Estimations of AGB from tree inventories are also a crucial point for the development of new methods of estimation, especially from above (plane, satellite). Tree inventories are the actual material for assessing carbon stocks. They produce a large range of datasets. Some cover small area and give hi-quality information: diameter at breast height (DBH), species Latin names, heights, ... Some datasets cover very large areas but give low-quality information: range of DBH instead of precise measure, family name or even no floristic specification, no heights, ... In addition, some other databases are required, like wood density data and weighted trees. For this study located in French Guiana, we use all of those kinds of datasets. To make correct inferences about biomass stocks and their evolution, it is essential to quantify the uncertainty associated with AGB estimates. It is also essential to answer those two questions: 1- Where does the uncertainty come from, and 2- How does it change with the data quality. To answer those questions, we calculate the AGB with a full hierarchical Bayesian model. It allows us to propagate errors through the model until the final AGB distribution. We can then perform a sensibility analysis, changing the error laws. The error laws are describing the uncertainty associated with every field measure. Both width and shapes may vary. Finally, we discuss the changes in AGB posterior distribution with the changes in error laws and data type. We also give some implication for both previous work and future experiments. (Résumé d'auteur

Strictness of Environmental Policy and Investment in Abatement

In this paper we model an oligopoly where .rms invest in abatement technologies and emissions are taxed by the government. We show that a stricter environmental policy does not necessarily lead to an increase in .rms.R&D investment into cleaner production methods. In fact, the emission-to-output ratio may be a U-shaped function of the environmental damage parameter. This result holds both when the government can commit and in the social optimum. When the government cannot commit, this relationship is ambiguous except in markets with few .rms. Our results further suggest that if the emission-to-output ratio is decreasing throughout, output is a U-shaped function of the environmental damage.Environmental innovation; environmental taxation; commitment; oligopoly

Entry and Exit in a Liberalised Market.

We analyze the determinants of entry and exit in the European Airline Markets in the post-liberalization period. Unlike previous studies, we find that the presence of charter or seasonal operators and the level of quality provided by the incumbents are relevant to explain entry and exit. Differential traits in the main low cost airlines' entry and exit behavior are also analysed.Entry, Exit, Airlines, Conditional Logit

Flexible vs Dedicated Technology Adoption in the Presence of a Public Firm

We study firms' adoption of flexible versus dedicated technologies in the context of a mixed versus a private duopoly with product differentiation. The flexible technology allows a firm to become multiproduct or multimarket without bearing additional costs. We find that a configuration where both firms adopt flexible technologies is more likely to arise in equilibrium in the private duopoly. A similar result occurs when both firms use a dedicated technology in the case of either almost independent products or products that are close substitutes. Privatization of the public firm is socially beneficial only in limited circumstances.Flexible Technology, Privatization, Public Firm, Mixed Duopoly.

La Intervención social de la policía vista desde una comisaría urbana: la comisaría de centro de Madrid.

Sin resume

Response perseveration and the triarchic model of psychopathy in an undergraduate sample.

This study aimed to extend previously reported links between distinctive configurations of traits in the psychopathic personality and maladaptive response perseveration, by examining performance in the Card Perseveration Task (CPT) within the framework of the triarchic model of psychopathy in a mixed-gender undergraduate sample. A computerized version of the CPT was administered to 222 undergraduates (142 women) assessed for triarchic psychopathy dimensions using the Triarchic Psychopathy Measure (TriPM). Maladaptive response perseveration (more cards played and less money earned) was uniquely associated with trait boldness scores for both women and men. Moreover, analyses of response times following feedback indicated that poor performance on the CPT was related to lack of overall reflection. Further mediation analyses did not reveal significant effects of trait boldness on the response perseveration deficit through reflection times. Our results provide new evidence for the role of trait boldness in the failure to suspend reward-approach behavior in the face of increasing punishment contingencies, probably due to an absence of fear or insensitivity to punishment cues rather than to an unreflective response style

Confronting satellite and field measurement data to improve the understanding of carbon uptake by tree growth in French Guiana

Climate models predict a range of changes in the amazonian region, including increased frequency of extreme climatic events, increased average temperatures, increased atmospheric CO2 and reduced rainfall intensity. Understanding tree growth response to climate is important because wood production is the main way carbon enters the forest ecosystem. The response of tropical tree growth to changing climate could drive a change in the direction of the flux from terrestrial ecosystems to the atmosphere. Recently, the intra-annual variation of chlorophyll activity in Amazonia and in French Guiana has been assessed with the Enhanced Vegetation Index (EVI) from the MODIS satellite data. As unexpected, peak of biomass increment (early wet season), estimated with diameter increment, were not correlated with peak of chlorophyll activity (early dry season) in French Guiana. In our assumption, this could reflect different timing in the use of photosynthesis products by the plant for primary growth, i.e. shoot growth and leaves production, and secondary growth, i.e. diameter increment. Here we use three datasets covering French Guiana at an intra-annual time scale, MODIS EVI data, modeled intra-annual tree growth data and climate data, to (i) disentangling the timing of carbon use by the trees for primary growth and secondary growth; (ii) analyze the climate determinants of these two components of growth; and (iii) predict the effect of climate change with IPCC scenarios outputs on the carbon entry in the forests of French Guiana. (Résumé d'auteur