Survey on the chemical composition of several tropical wood species

Variability in the chemical composition of 614 species is described in a database containing measurements of wood polymers (cellulose, lignin and pentosan), as well as overall extraneous components (ethanol-benzene, or hot water extracts and ash, with a focus on silica content). These measurements were taken between 1945 and 1990 using the same standard protocol. In all, 1,194 trees belonging to 614 species, 358 genera and 89 families were measured. At species level, variability (quantified by the coefficient of variation) was rather high for density (27%), much lower for lignin and cellulose (14% and 10%) and much higher for ethanol/benzene extractives, hot water extractives and ash content (81%, 60% and 76%). Considering trees with at least five different specimens, and species with at least 10 different trees, it was possible to investigate within-tree and withinspecies variability. Large differences were found between trees of a given species for extraneous components, and more than one tree should be needed per species. For density, lignin, pentosan and cellulose, the distribution of values was nearly symmetrical, with mean values of 720 kg/m3 for density, 29.1% for lignin, 15.8% for pentosan, and 42.4% for cellulose. There were clear differences between species for lignin content. For extraneous components, the distribution was very dissymmetrical, with a minority of woods rich in this component composing the high value tail. A high value for any extraneous component, even in only one tree, is sufficient to classify the species in respect of that component. Siliceous woods identified by silica bodies in anatomy have a very high silica content and only those species deserve a silica study

Survey on the chemical composition of several tropical wood species

Variability in the chemical composition of 614 species is described in a database containing measurements of wood polymers (cellulose, lignin and pentosan), as well as overall extraneous components (ethanol-benzene, or hot water extracts and ash, with a focus on silica content). These measurements were taken between 1945 and 1990 using the same standard protocol. In all, 1,194 trees belonging to 614 species, 358 genera and 89 families were measured. At species level, variability (quantified by the coefficient of variation) was rather high for density (27%), much lower for lignin and cellulose (14% and 10%) and much higher for ethanol/benzene extractives, hot water extractives and ash content (81%, 60% and 76%). Considering trees with at least five different specimens, and species with at least 10 different trees, it was possible to investigate within-tree and withinspecies variability. Large differences were found between trees of a given species for extraneous components, and more than one tree should be needed per species. For density, lignin, pentosan and cellulose, the distribution of values was nearly symmetrical, with mean values of 720 kg/m3 for density, 29.1% for lignin, 15.8% for pentosan, and 42.4% for cellulose. There were clear differences between species for lignin content. For extraneous components, the distribution was very dissymmetrical, with a minority of woods rich in this component composing the high value tail. A high value for any extraneous component, even in only one tree, is sufficient to classify the species in respect of that component. Siliceous woods identified by silica bodies in anatomy have a very high silica content and only those species deserve a silica study

Edition de l'ouvrage : Atlas des bois tropicaux - 1ère édition - Caractéristiques technologiques et utilisations de 283 essences tropicales (et 17 tempérées) - projet OIBT TMT-SPD 010/12 Rev.1 (M)

* Au milieu des années 1980, l'Organisation Internationale des Bois tropicaux (OIBT) a confié au Centre technique forestier tropical (CTFT, département forestier du CIRAD) la conception et la réalisation d'un logiciel de gestion des caractéristiques technologiques des bois tropicaux. La première version de ce logiciel fonctionnait à l'aide du système d'exploitation DOS. Il fût un des premiers logiciels du genre, sinon le premier, dont l'objectif était de contribuer à promouvoir et développer la commercialisation et l'utilisation des bois tropicaux, notamment des essences secondaires. Par la suite, l'équipe Bois tropicaux du CTFT-CIRAD a fait évoluer ce logiciel et l'a progressivement enrichi (augmentation du nombre d'essences décrites et du nombre de caractéristiques présentées). Vers le milieu des années 1990, ce logiciel a été transféré sous le système d'exploitation Windows et a été plus largement diffusé sous le nom " Tropix ". L'Unité de Recherche Bois tropicaux puis l'Unité BioWooEB du Cirad ont fait évoluer ce logiciel et l'ont enrichi. Sa dernière version 7.5.1 (2015) présente les caractéristiques technologiques de 245 essences, dont 17 tempérées. Aujourd'hui, ce logiciel est largement utilisé par les opérateurs de la filière-bois, en France et à l'étranger. * Entre 1986 et 1990, trois ouvrages de référence sur les bois tropicaux ont été successivement publiés : - l'Atlas des bois tropicaux - Tome 1 Afrique (ATIBT – CTFT), publié en français et en anglais. - l'Atlas des bois tropicaux - Tome 2 Asie-Australie-Océanie (ATIBT), publié en français et en anglais. - l'Atlas des bois tropicaux d'Amérique Latine (CTFT – OIBT – ATIBT), publié en français, en anglais et en espagnol (sur financement OIBT). Ces trois ouvrages sont toujours très utilisés par les opérateurs des filières bois tropicales mais sont épuisés et certaines informations nécessitent une réactualisation et des compléments. Ces opérateurs sont donc demandeurs d'un ouvrage sur les essences tropicales présentant des données et informations actualisées qui répondent à leurs attentes et à leurs besoins. Le logiciel Tropix 7.5.1 présentant l'essentiel de ces données et informations, il est apparu opportun de les organiser et de les présenter sous la forme d'un ouvrage (papier et électronique) " L'Atlas des bois tropicaux ", pour succéder aux trois ouvrages sur les bois d'Afrique, d'Amérique latine et d'Asie-Océanie. Dans le cadre de son programme thématique Transparence du commerce et des marchés (TMT), l'Organisation internationale des Bois tropicaux a accepté de soutenir financièrement la conception et la réalisation de ce nouvel ouvrage à travers le projet TMT-SPD 010/12 Rev.1 (M) intitulé " Edition de l'ouvrage : Atlas des bois tropicaux - 1ère édition – Caractéristiques technologiques et utilisations de 273 essences tropicales (et 17 tempérées) ". Le contenu de cet Atlas présente de nombreux compléments par rapport à la dernière version de Tropix qui a été largement remaniée, mise à jour et complétée : - 55 nouvelles essences sont décrites en plus des 245 actuelles, soit un total de 300 essences dont les principales caractéristiques technologiques et les utilisations effectives ou potentielles sont présentées, - les valeurs de pouvoir calorifique inférieur et de conductivité thermique des bois ont été ajoutées aux descriptifs technologiques, - les programmes de séchage ont été entièrement remaniés en utilisant comme référence les programmes édités par Cathild Industrie, - chacune des 300 essences décrites est illustrée à l'aide de trois types de photographies : . deux macrophotographies grossissement 20 et grossissement 115, . deux photos de débit sur dosse et sur quartier (ou faux quartier), . une photo d'un ouvrage réalisé à partir du bois décrit (lorsque ce type de photo était disponible) : construction, aménagement extérieur, menuiserie, meuble, instrument de musique, objet d'art… Cet ouvrage a vocation à constituer un outil de référence pour tous les opérateurs de la filièrebois, en France et à l'étranger, mais aussi pour les établissements de recherche et d'enseignement, pour les institutionnels, ainsi que pour les donneurs d'ordre, les architectes, les maitres d'oeuvre, les maitres d'ouvrage, et de façon générale pour tous les professionnels qui transforment et mettent en oeuvre des bois tempérés ou tropicaux, ou qui projettent de le faire. (Résumé d'auteur

Variétés linguistiques et intelligibilité : enjeux sociolinguistiques pour la synthèse de parole

Cet article discute de l’opportunité de développer des systèmes de synthèse de parole qui utilisent une variété linguistique plus familière. Les résultats de trois expériences présentées ici, en particulier la troisième qui repose sur une tâche plus élaborée de décision lexicale, font ressortir que les stimuli produits en français québécois sont plus facilement reconnus par des locuteurs québécois que ceux produits dans une variété européenne. Cela suggère que la variété linguistique utilisée peut agir à la façon d’un filtre qui facilite ou, au contraire, gêne la perception et le traitement des mots.This paper is related to the opportunity of using a vernacular variety in speech synthesis instead of a more formal one. The results of three experiments, especially those of the more elaborated one based on a lexical decision task, point out that stimuli spoken in a Quebec French variety are more easily processed by Quebec French speaking subjects than those spoken in an European variety. These results suggest that the linguistic variety acts as a filter that may facilitate or, on the contrary, impede and slow down the processing of words

Diagnostic préalable du marché alimentaire local sur le Pays de la Haute vallée de l'Aude et des Pyrénées Audoises

Ce rapport est le résultat de l’étude exécutée par les élèves de l’École d’Ingénieurs de Purpan sur le Pays de la Haute Vallée de l’Aude. Le diagnostic a révélé que ce territoire d’arrière-pays est composé d’entités territoriales multiples avec une démographie, des paysages et des activités économiques variés. Sur cet ancien bassin industriel, le tourisme et l’agriculture ont progressivement pris le pas sur l’industrie en tant qu’activité économique mais ne sont cependant pas exploités à leur optimum. Le principal enjeu de développement du territoire révélé est d’organiser conjointement les filières du tourisme, du bois et de production/distribution des produits locaux. Aussi, le maintien de la qualité de vie avec en autre le développement des transports et des services à la population a été identifié comme enjeux de développement sur le territoire. Afin de répondre à ces enjeux, le pays pourra mettre en action les préconisations formulées. Elles ont comme objectif d’exploiter les potentialités du territoire de manière cohérente. Parmi ces préconisations, la structuration et la coordination des activités et des acteurs est primordiale. Pour cela, il est important de fédérer la population autour d’une identité commune et de la mobiliser autour d’objectifs communs

Impact of improved systems on rice and common carp Cyprinus carpio multitrophic tropical aquaculture, Antananarivo, Madagascar

Flooded rice fields are ecosystems favorable to the growth and production of many aquatic organisms. They can even play a major role in the feeding and nutrition of local communities, as a source of self-recruiting species or by supporting the production of farmed fish in association with rice. In Madagascar, integrated rice-fish aquaculture systems are a 150+ years-old tradition. The initial species was goldfish Carassius auratus, locally known as Trondro gasy (meaning, “the Malagasy fish”) but now, the common carp (Cyprinus carpio) took over as the main produced species, sometimes in polyculture with tilapia. Although traditional, the technology has recently been improved by several organizations (FAO, APDRA) by building larger and higher side dykes and digging a canal in the middle of the field, which serves as a refuge area for fish when the field is drained. However, this also implies an approximate 10% loss of space for rice production, a basic food commodity for local populations, which is supposedly compensated by higher rice productivity in integrated system. The first aim of this farm experiment was therefore to assess the productivity of these systems by characterizing the importance of the different trophic compartments in traditional (rice + self recruiting species) and integrated systems (rice+carps improved systems, Fig. 1). However, nutrient availability can be a limiting factor, as feed and fertilizers are expensive. Trophic deadlocks can then be suspected in iron-rich areas due to phosphorous chelation in sediments. As common carp is a detritivore/omnivore fast-growing species which trophic behavior (bioturbation) involves re-suspending sediments, it is expected that its introduction in inundated rice field will improve nutrient availability and increase rice and fish production. The second scientific question is then focused on determining the nutrient pathways and deadlocks, and how they impact the common carp, rice and fish production. (Résumé d'auteur

Extinction map of the Small Magellanic Cloud based on SIRIUS and 6X 2MASS point source catalogs

In this paper, we present the first extinction map of the Small Magellanic Cloud (SMC) constructed using the color excess at near-infrared wavelengths. Using a new technique named "X percentile method", which we developed recently to measure the color excess of dark clouds embedded within a star distribution, we have derived an E(J – H) map based on the SIRIUS and 6X Two Micron All Sky Survey (2MASS) star catalogs. Several dark clouds are detected in the map derived from the SIRIUS star catalog, which is deeper than the 6X 2MASS catalog. We have compared the E(J – H) map with a model calculation in order to infer the locations of the clouds along the line of sight, and found that many of them are likely to be located in or elongated toward the far side of the SMC. Most of the dark clouds found in the E(J – H) map have counterparts in the CO clouds detected by Mizuno et al. with the NANTEN telescope. A comparison of the E(J – H) map with the virial mass derived from the CO data indicates that the dust-to-gas ratio in the SMC varies in the range A_V /N_H = 1-2 × 10^(–22) mag H^-1 cm^2 with a mean value of ~1.5 × 10^(–22) mag H^-1 cm^2. If the virial mass underestimates the true cloud mass by a factor of ~2, as recently suggested by Bot et al., the mean value would decrease to ~8×10^(–23) mag H^-1 cm^2, in good agreement with the value reported by Gordon et al., 7.59 × 10^(–23) mag H^-1 cm^2

Statistical study of dust properties in LMC molecular clouds

The objective of this paper is to construct a catalog providing the dust properties and the star formation efficiency (SFE) of the molecular clouds in the Large Magellanic Cloud (LMC). We use the infrared (IR) data obtained with the Spitzer telescope as part of the ``Surveying the Agents of a Galaxy's Evolution'' (SAGE) Legacy survey as well as the IRAS data. We also work with extinction (Av) maps of the LMC. A total of 272 molecular clouds have been detected in the LMC in a previous molecular survey, accounting for 230 giant molecular clouds and 42 smaller clouds. We perform correlations between the IR emission/extinction, and atomic and molecular gas tracers. We compare the atomic gas that surrounds the molecular cloud with the molecular gas in the cloud. Using a dust emission model, we derive the physical properties of dust in and outside the clouds: equilibrium temperature, emissivity and extinction. We also determine the luminosity of the interstellar radiation field intercepted by the cloud, and the total IR luminosity. Statistically, we do not find any significant difference in the dust properties between the atomic and the molecular phases. In particular we do not find evidence for a systematic decrease of the dust temperature in the molecular phase, with respect to the surrounding, presumably atomic gas. This is probably because giant molecular clouds are the sites of star formation, which heat the dust, while the smallest clouds are unresolved. The ratio between the IR luminosity and the cloud mass (LDust/Mgas) does not seem to correlate with Mgas. The highest value of the ratio we derived is 18.1 Lsol/Msol in the 30 Doradus region, which is known to be the most prominent star formation region of the LMC, while the most likely value is 0.5 and is representative of quiescent clouds. We provide a prescription to associate the various stages of star formation with its LDust/Mgas.Comment: Accepted for publication in A

Transient Activity in the Human Calcarine Cortex During Visual-Mental Imagery: An Event-Related fMRI Study

Although it is largely accepted that visual-mental imagery and perception draw on many of the same neural structures, the existence and nature of neural processing in the primary visual cortex (or area V1) during visual imagery remains controversial. We tested two general hypotheses: The first was that V1 is activated only when images with many details are formed and used, and the second was that V1 is activated whenever images are formed, even if they are not necessarily used to perform a task. We used event-related functional magnetic resonance imaging (ER-fMRI) to detect and characterize the activity in the calcarine sulcus (which contains the primary visual cortex) during single instances of mental imagery. The results revealed reproducible transient activity in this area whenever participants generated or evaluated a mental image. This transient activity was strongly enhanced when participants evaluated characteristics of objects, whether or not details actually needed to be extracted from the image to perform the task. These results show that visual imagery processing commonly involves the earliest stages of the visual system.Psycholog

Technological characteristics of 245 tropical and temperate timbers species

Developed by the Cirad's "Mediterranean and Tropical Forest Products Research Unit", the new release of TROPIX software (version 7) presents the main characteristics of 245 tropical or temperate wood species. For each species, TROPIX provides data and information on: the scientific and local names of the species described, their origins (distribution maps) and any commercial restriction according to the CITES regulation; appearance of the log or wood, including pictures of wood and wood utilisations; leading physical and mechanical properties; natural durability against fungi / dry wood borers / termites, and preservation; drying behaviour, including a drying schedule given for information; processing behaviour (sawing, machining, assembling); appearance grading and visual grading for structural applications; actual and potential uses and reaction to fire. Some of this information is displayed in graphical format. TROPIX 7 allows multicriteria search using preselected search terms or similarity to a different species. It also allows graphical species comparisons based on one or two physical or mechanical properties. Multicriteria searches results, graphics and technical sheets can be printed or exported as files. (Résumé d'auteur