La guerre du Golfe, la presse et les cartes en Équateur: la banalisation d'un conflit multinational (janvier 1991)

Cette première guerre retransmise «en direct» par les chaînes de télévision du monde entier — ce qui n’exclut pas la censure —, se caractérise par la quasi-unicité des sources d’information primaire, la recherche du sensationnalisme et la banalisation d’affrontements multinationaux. Le dépouillement des deux principaux quotidiens équatoriens permet de lier le volume d’information aux phases des hostilités et d’analyser le langage cartographique et les messages à transmettre à l’humanité

Northern High-Latitude Ecosystems Respond to Climate Change

The northern high latitudes are an area of particular importance to global climate change. As a system dependent on freezing conditions, the top of the planet contains vast amounts of carbon in biomass, soils, and permafrost that have the potential to interact with the atmosphere through the biosphere, hydrosphere, lithosphere, and cryosphere. If released en masse, this carbon would greatly exacerbate the levels of greenhouse gases in the atmosphere. Over the past 2 years, a growing body of research has provided evidence of substantial but idiosyncratic environmental changes, with some surprising aspects, across the region. This article reviews some recent findings and presents a new analysis of northern vegetation photosynthetic and productivity trends tracked from Earth observing satellites

A milestone toward understanding PDR properties in the extreme environment of LMC-30Dor

More complete knowledge of galaxy evolution requires understanding the process of star formation and interaction between the interstellar radiation field and the interstellar medium in galactic environments traversing a wide range of physical parameter space. Here we focus on the impact of massive star formation on the surrounding low metallicity ISM in 30 Doradus in the Large Magellanic Cloud. A low metal abundance, as is the case of some galaxies of the early universe, results in less ultra-violet shielding for the formation of the molecular gas necessary for star formation to proceed. The half-solar metallicity gas in this region is strongly irradiated by the super star cluster R136, making it an ideal laboratory to study the structure of the ISM in an extreme environment. Our spatially resolved study investigates the gas heating and cooling mechanisms, particularly in the photo-dissociation regions where the chemistry and thermal balance are regulated by far-ultraviolet photons (6 eV< h\nu <13.6 eV). We present Herschel observations of far-infrared fine-structure lines obtained with PACS and SPIRE/FTS. We have combined atomic fine-structure lines from Herschel and Spitzer observations with ground-based CO data to provide diagnostics on the properties and the structure of the gas by modeling it with the Meudon PDR code. We derive the spatial distribution of the radiation field, the pressure, the size, and the filling factor of the photodissociated gas and molecular clouds. We find a range of pressure of ~ 10^5 - 1.7x10^6 cm^{-3} K and a range of incident radiation field G_UV ~ 10^2 - 2.5x10^4 through PDR modeling. Assuming a plane-parallel geometry and a uniform medium, we find a total extinction of 1-3 mag , which correspond to a PDR cloud size of 0.2 to 3pc, with small CO depth scale of 0.06 to 0.5pc. We also determine the three dimensional structure of the gas. (Abridged)Comment: 20 pages, 23 figures, accepted in A&

OH+ in astrophysical media: state-to-state formation rates, Einstein coefficients and inelastic collision rates with He

The rate constants required to model the OH$^+$ observations in different regions of the interstellar medium have been determined using state of the art quantum methods. First, state-to-state rate constants for the H$_2(v=0,J=0,1)$+ O$^+$($^4S$) $\rightarrow$ H + OH$^+(X ^3\Sigma^-, v', N)$ reaction have been obtained using a quantum wave packet method. The calculations have been compared with time-independent results to asses the accuracy of reaction probabilities at collision energies of about 1 meV. The good agreement between the simulations and the existing experimental cross sections in the $0.01-$1 eV energy range shows the quality of the results. The calculated state-to-state rate constants have been fitted to an analytical form. Second, the Einstein coefficients of OH$^+$ have been obtained for all astronomically significant ro-vibrational bands involving the $X^3\Sigma^-$ and/or $A^3\Pi$ electronic states. For this purpose the potential energy curves and electric dipole transition moments for seven electronic states of OH$^+$ are calculated with {\it ab initio} methods at the highest level and including spin-orbit terms, and the rovibrational levels have been calculated including the empirical spin-rotation and spin-spin terms. Third, the state-to-state rate constants for inelastic collisions between He and OH$^+(X ^3\Sigma^-)$ have been calculated using a time-independent close coupling method on a new potential energy surface. All these rates have been implemented in detailed chemical and radiative transfer models. Applications of these models to various astronomical sources show that inelastic collisions dominate the excitation of the rotational levels of OH$^+$. In the models considered the excitation resulting from the chemical formation of OH$^+$ increases the line fluxes by about 10 % or less depending on the density of the gas

High-resolution absorption spectroscopy of the OH 2Pi 3/2 ground state line

The chemical composition of the interstellar medium is determined by gas phase chemistry, assisted by grain surface reactions, and by shock chemistry. The aim of this study is to measure the abundance of the hydroxyl radical (OH) in diffuse spiral arm clouds as a contribution to our understanding of the underlying network of chemical reactions. Owing to their high critical density, the ground states of light hydrides provide a tool to directly estimate column densities by means of absorption spectroscopy against bright background sources. We observed onboard the SOFIA observatory the 2Pi3/2, J = 5/2 3/2 2.5 THz line of ground-state OH in the diffuse clouds of the Carina-Sagittarius spiral arm. OH column densities in the spiral arm clouds along the sightlines to W49N, W51 and G34.26+0.15 were found to be of the order of 10^14 cm^-2, which corresponds to a fractional abundance of 10^-7 to 10^-8, which is comparable to that of H_2O. The absorption spectra of both species have similar velocity components, and the ratio of the derived H_2O to OH column densities ranges from 0.3 to 1.0. In W49N we also detected the corresponding line of ^18OH

Petrology and Geochemistry of Serpentinites Associated with the Ultra-High Pressure Lago di Cignana Unit (ItalianWestern Alps)

In the Western Alps, the ophiolitic Zermatt–Saas Zone (ZSZ) and the Lago di Cignana Unit (LCU) record oceanic lithosphere subduction to high (540°C, 2·3GPa) and ultra-high pressure (600°C, 3·2GPa), respectively. The top of the Zermatt–Saas Zone in contact with the Lago di Cignana Unit consists of olivine þ Ti-clinohumite-bearing serpentinites (the Cignana serpentinite) hosting olivine þ Ti-clinohumite veins and dykelets of olivine þ Ti-chondrodite þ Ti-clinohumite. The composition of this serpentinite reveals a refertilized oceanic mantle peridotite protolith that became subsequently enriched in fluid-mobile elements (FME) during oceanic serpentinization. The olivine þ Ti-clinohumite veins in the Cignana serpentinite display Rare Earth Element (REE) and FME compositions quite similar to the host-rock, which suggests closed-system dehydration of this serpentinite during subduction. The Ti-chondrodite-bearing dykelets are richer in REE and FME than the host-rock and the dehydration olivine þ Ti-clinohumite veins: their Nd composition points to a mafic protolith, successively overprinted by oceanic metasomatism and by subduction zone recrystallization. These dykelets are comparable in composition to eclogites within the ultra-high pressure LCU that derive from subducted oceanic mafic crust. Different from the LCU, serpentinites from the core domains of the ZSZ display REE compositions indicating a depleted mantle protolith. The oceanic serpentinization of these rocks led to an increase in FME and to seawater-like Sr isotope compositions. The serpentinites sampled at increasing distance from the ultra-high pressure LCU reveal different mantle protoliths, still preserve an oceanic geochemical imprint and contain mafic dykelets affected by oceanic metasomatism. The subduction zone history of these rocks thus occurred under relatively closed system conditions, the only possible change during subduction being an enrichment in As and Sb recorded by the serpentinites closer to the crustal LCU. The ZSZ and Cignana serpentinites thus likely evolved in a slab setting and were weakly exposed to interaction with slab-derived fluids characteristic of plate interface settings. Our data suggest two possible scenarios for the evolution of the studied ZSZ and Cignana serpentinites. They are either part of a coherent ophiolite unit whose initial lithospheric mantle was variably affected by depletion and re-fertilization processes, or they belong to separate tectonic slices derived from two different oceanic mantle sections. In the Cignana serpentinite atop the ZSZ, the presence of Ti-chondrodite dykelets similar in composition to the LCU eclogites suggests these two domains were closely associated in the oceanic lithosphere and shared the same evolution to ultra-high pressure conditions during Alpine subduction

The Nineteenth Century Engagement Between Geological and Adventist Thought and its Bearing on the Twentieth Century Flood Geology Movement

The Seventh-day Adventist Church has from the early years of its existence reacted to the perceived challenge of geological thought to their nascent theology. In particular, the Sabbath of the fourth Commandment in Genesis 2 and the catastrophic global Flood described in Genesis 7 and 8 were targeted. The nineteenth century Adventist response has been one of shifting focus, changing strategies, and increasing intensity. Ellen White, the church’s co-founder and prophetess, was one of the first to sound a warning on theological implications of geology. Her perception of geology contained many pre-nineteenth century concepts disconnected from contemporary geological thinking. Long-time editor Uriah Smith used external documents, notably Presbyterian writings to guide the Adventist congregation with ways of responding to geological thought as it impacted on their faith. The first authentic Adventist evaluation of geology and its perceived link with evolution by Alonzo Jones took place in the mid-1880s. With his spirited response, Jones criticised geological stratigraphic concepts in order to neutralise the threat of burgeoning theistic evolutionary thought. His searching in the geological literature involved the use of contextomy. George McCready Price next ventured to nullify the established stratigraphic principles of geology in order to justify a single, global flood-based hypothesis to explain all fossiliferous sedimentary formations. To achieve this, he presented from established scientists selected citations out of their intended context. A special case is presented on Price’s questionable use of the reports of American field geologists McConnell and Willis on thrust faults in the Rocky Mountains. Price modified diagrams and failed to convey unmistakable evidence of a dynamic cause of complex stratigraphy to present his case for the global existence of reverse sequences of rock strata. He argued that since the geologists’ evidence for a fossil sequence of life in the rock stratigraphy is so greatly flawed, there must have been a single catastrophic event that better explained this. Adventist engagement with geological thought during this period saw a noticeable increase in the disregard of intellectual integrity. This study argues that intellectual dishonesty is not a valid way to support a preconceived interpretation of the scriptural narrative. History provides several examples where skewed accounts of events due to questionable intellectual sincerity have eventually been corrected. This research provides access points for interested persons to further investigate the historical aspects of the nineteenth century geology and Adventist thought engagement

A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments

Most speech and language technologies are trained with massive amounts of speech and text information. However, most of the world languages do not have such resources or stable orthography. Systems constructed under these almost zero resource conditions are not only promising for speech technology but also for computational language documentation. The goal of computational language documentation is to help field linguists to (semi-)automatically analyze and annotate audio recordings of endangered and unwritten languages. Example tasks are automatic phoneme discovery or lexicon discovery from the speech signal. This paper presents a speech corpus collected during a realistic language documentation process. It is made up of 5k speech utterances in Mboshi (Bantu C25) aligned to French text translations. Speech transcriptions are also made available: they correspond to a non-standard graphemic form close to the language phonology. We present how the data was collected, cleaned and processed and we illustrate its use through a zero-resource task: spoken term discovery. The dataset is made available to the community for reproducible computational language documentation experiments and their evaluation.Comment: accepted to LREC 201

Interleukin-4 (IL-4), but not IL-10, regulates the synthesis of IL-6, IL-8 and leukemia inhibitory factor by human bone marrow stromal cells

AbstractLeukemia inhibitory factor (LIF), interleukin 6 (IL-6) and IL-8 are important regulators of inflammation and hematopoiesis. Human bone marrow stromal cells regulate marrow hematopoiesis by secreting cytokines. By using reverse-transcriptase polymerase chain reaction (RT-PCR), we demonstrate that human bone marrow stromal cells constitutively express LIF, IL-6 and IL-8 transcripts. By using specific ELISAs, we found that their spontaneous productions of LIF, IL-6 and IL-8 are elevated in response to serum and after stimulation with the pro-inflammatory cytokines IL-1α and TNF-α. The anti-inflammatory cytokine IL-4 reduces their serum- and cytokine-induced LIF secretion. By contrast, IL-4 stimulates their serum- and IL-1α-induced IL-6 synthesis. IL-4 has no effect on the serum-induced IL-8 synthesis by marrow stromal cells, but stimulates their cytokine-induced IL-8 production. The anti-inflammatory cytokine IL-10 has no effect on the serum- and cytokine-induced LIF, IL-6 and IL-8 synthesis by bone marrow stromal cells. RT-PCR experiments reveal the presence of IL-4 receptor α-chain mRNA and IL-10 receptor mRNA in cultured bone marrow stromal cells. The differential regulation by IL-4 of two related cytokines, such as LIF and IL-6, and the enhanced effect of this ‘anti-inflammatory’ cytokine on IL-6 and IL-8 synthesis highlight the tightly controlled regulation and the complexity of the cytokine production within the human bone marrow

PLIF Measurements of Nitric Oxide and Hydroxyl Radicals Distributions in Swirled Stratified Premixed Flames

Environmental and economic concerns have pushed aeronautical authorities to set stringent environmental regulations on fuel consumption, noise production, and pollutant emission. Engine manufacturers are developing novel staged injection concepts to ensure their respect. The injection staging creates a fuel-air mixture stratification involving new combustion processes not fully understood. This paper presents the experimental investigation of NO production for known swirled and / or stratified lean premixed flames. The fuel staging parameter defined as the stratification ratio is studied for values of 1, 2, and 3, while the swirl fractions are 0, 25 and 33%, changing the flowfield from non-swirling cond itions to high swirl numbers (up to 0.55). The implementation of simultaneous OH- and NOPLIF imaging techniques is achieved using high energy pulsed laser systems, able, for instance, to deliver 30 mJ/ pulse around the 226-nm UV wavelength for NO excitation. OH-PLIF is used to characterize the flame structure through the commonly extracted curvature, and also through the measurement of the flame thickness. These results show to be more accurate than thickness obtained from temperature profiles measured by Raman/ Rayleigh laser diagnostics. NO-PLIF is used to quantify the pollutant concentration. To this end, preliminary work was done to select the Q1 (29.5) transition as it the least temperature dependent excitation scheme with high fluorescence levels. After realizing a specific calibration of the NO-PLIF technique, the stud ied flames presented concentrations ranging from traces (20 ppm) to high levels (230 ppm). Further analysis of these results reveals that for high stratification ratios the prompt NO is favored and is responsible for the elevated level of NO pollutant