Internet et la liberté d'expression : l'exemple des critiques dirigées contre les oligopoles

"Mémoire présenté à la Faculté des études supérieures en vue de l'obtention du grade de maîtrise en droit option droit des technologies de l'information"Ce mémoire de maîtrise présente une situation dans laquelle un citoyen ordinaire tente de diffuser sur Internet une opinion critique qu'il dirige contre une grande entreprise commerciale et tente d'analyser les éléments favorables à la diffusion de cette opinion critique ainsi que les embûches qui sont à prévoir. Cet exemple permet d'illustrer les forces et les faiblesses d'Internet en matière de liberté d'expression. Il permet de poser une mise en garde concernant les dangers de transposer les limites actuelles à la liberté d'expression des citoyens au contexte d'Internet. La première partie de l'analyse souligne les caractéristiques d'Internet et les différentes façons d'aborder la question de la liberté d'expression sur Internet selon les approches libertaire, libérale ou interventionniste, pour finalement faire le point sur l'apport d'Internet en matière d'information et de communication. La deuxième partie de l'analyse aborde la question de l'efficience en identifiant les éléments qui encouragent l'exercice de la liberté d'expression et ceux qui découragent les utilisateurs de s'exprimer sur Internet. L'exemple des critiques dirigées contre les oligopoles permet d'illustrer la nécessité d'établir des règles propres à Internet en matière de liberté d'expression. Cet exemple fait ressortir le caractère inadéquat des limites actuelles à la liberté d'expression établies par le droit de la presse, le droit de la radiodiffusion, le droit de propriété et le droit de la propriété intellectuelle. L'auteur vient à la conclusion qu'en matière de liberté d'expression, il serait souhaitable: 1) Que Internet soit considéré comme un espace public de discussion; 2) Que la préséance des intérêts économiques sur les intérêts démocratiques au niveau du développement de la société de l'information soit avouée; 3) Que les inégalités en termes d'opportunités d'expression soient reconnues; 4) Que les limites imposées en vertu des règles du droit de la propriété soient reconsidérées à la lumière des caractéristiques d'Internet.This master thesis presents a case in which an ordinary citizen tries to spread on the Internet a criticizing opinion aimed at a large company, and attempts to analyse what are the elements in favour of this criticism broadcasting, as weil as the obstacles to be expected. This example allows us to illustrate the strengths and weaknesses of the Internet in matter of freedom of speech. It also allows to put forward a warning concerning the risks of transposing current Iimits of freedom of speech in an Internet context. The first part of the analysis underlines the Internet's characteristics and the different ways to broach the subject of freedom of speech over the Internet, following severaI approaches, to finally focus on the Internet's contribution in matter of information and communication. The second part of the analysis deals with the question of efficiency, while identifying the elements that encourage the exercise of freedom of speech and those that discourage Internet users from expressing themselves. The example of criticism aimed toward large companies allows to illustrate the need to establish the Internet's own rules in matter of freedom of speech. What emerges from this example is the inadequate character of current limits to freedom of speech as set up by freedom of the press, broadcasting law, property and intellectual property law. The author concludes that in matter of freedom of speech, it wouId be recommended: 1) that the Internet be considered as a public forum; 2) that the predominance of economic interests over democratic interests in the development of the information society be admitted; 3) that the inequalities in terms of expression opportunities be recognized; 4) that the limits imposed in accordance with property law be reconsidered in an Internet context

Characterizing the Feeding Habits of the Testate Amoebae Hyalosphenia papilio and Nebela tincta along a Narrow "Fen-Bog" Gradient Using Digestive Vacuole Content and (13)C and (15)N Isotopic Analyses.

International audiencePopulation dynamics and feeding habits of the testate amoebae Nebela tincta and Hyalosphenia papilio were studied along a short "fen" to "bog" gradient in a Sphagnum-dominated mire (Jura, France). Samples were collected in living "top segments" (0-3cm) and early declining "bottom segments" (3-6cm) of Sphagnum fallax peat. Observations of digestive vacuole content and stable isotope analyses ((13)C and (15)N) were used to establish the feeding behavior of both testate amoeba species. Owing to their vertical distribution, the feeding habit of H. papilio was described from top segments, and that of N. tincta from bottom segments. Among identified food sources, those most frequently ingested by N. tincta were spores and mycelia of fungi (55%), microalgae (25%) and cyanobacteria (8.5%). For H. papilio, the most frequently ingested prey were ciliates (55%) and microalgae (35%). Nonmetric Multidimensional Scaling analysis clearly demonstrated that the two species did not have the same feeding habit along the "fen-bog" gradient, and furthermore that a significant spatial split exists in the feeding behavior of H. papilio. Additionally, isotope analyses suggested that H. papilio and N. tincta did not have the same trophic position in the microbial food web, probably resulting from their different feeding strategies

Phenoloxidase and peroxidase activities in Sphagnum-dominated peatland in a warming climate

International audiencePeatlands still suffer from the scarcity of available data about the characterization and the response to climate forcing of the main oxidative enzymes that occur over the seasons. In the present study, phenoloxidase and peroxidase activities were examined in Sphagnum lawns along a narrow fen-bog gradient under experimental elevated temperatures. We showed that peroxidase activities from Sphagnum mosses were 1000-fold higher than those of phenoloxidases irrespective of seasons and sampling areas. Peroxidase activities increased (+30%) with the rise of air temperatures (an average of 1 °C), while warming did not alter phenoloxidase activities. These results suggest that the monitoring of peroxidase activities in peatlands may represent a suitable and forward indicator of the impact of climate warming on carbon cycle in peatlands

Effect of a temperature gradient on Sphagnum fallax and its associated living microbial communities: a study under controlled conditions.

International audienceMicrobial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25°C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0-3 cm and 3-6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities

Occurrence and distribution of glycerol dialkyl glycerol tetraethers in a French peat bog

International audienceThe present study was aimed at examining the distribution and abundance of glycerol dialkyl glycerol tetraethers (GDGTs) of archaeal and bacterial origin in peat samples from surface and deep (ca. 50 cm) horizons of a peat bog in the Jura Mountains (northeastern France). Two principal types of GDGTs are present: extractable GDGTs, recoverable by solvent extraction, and non-extractable GDGTs, linked to the soil matrix. Within the extractable pool, “free” (i.e. core lipids) and “bound” (i.e. intact polar and/or ester-bound lipids) GDGTs can be distinguished. Extractable “free” and “bound” GDGTs were extracted using both accelerated solvent extraction (ASE) and a modified Bligh and Dyer technique. Both methods were shown to allow adequate extraction of “free” archaeal and bacterial GDGTs from soil samples. Both extraction protocols afforded similar relative distributions of archaeal and bacterial GDGTs, although poorer extraction of “bound” GDGTs was observed for ASE relative to Bligh and Dyer. Even though only low amounts of bacterial GDGTs were released after acid hydrolysis of solvent-extracted samples, non-extractable and total extractable GDGTs showed different distribution patterns in some samples. Consequently, these two lipid pools potentially reflect different proxy records of mean annual air temperature (MAAT) and pH. Last, the distribution of bacterial GDGTs differed between the different samples. Samples from deep horizons gave lower GDGT-derived MAAT values than those from surficial horizons, in agreement with measured soil temperatures at 7 cm and 50 cm depths from April to September. MAAT estimates more closely resemble spring and summer temperatures rather than annual soil temperature. The variability in bacterial GDGT distribution and resulting MAAT estimates probably also reflects the heterogeneity of peat samples and the variation in several environmental factors such as peat moisture level and oxygen availability

Experimental climate effect on seasonal variability of polyphenol/phenoloxidase interplay along a narrow fen-bog ecological gradient in Sphagnum fallax

International audienceExtracellular phenoloxidase enzymes play an important role in the stability of soil carbon storage by contributing to the cycling of complex recalcitrant phenolic compounds. Climate warming could affect peatland functioning through an alteration of polyphenol/phenoloxidase interplay, which could lead them to becoming weaker sinks of carbon. Here, we assessed the seasonal variability of total phenolics and phenoloxidases subjected to 2-3 °C increase in air temperature using open-top chambers. The measurements were performed along a narrow fen-bog ecological gradient over one growing season. Climate warming had a weak effect on phenoloxidases, but reduced phenolics in both fen and bog areas. Multivariate analyses revealed a split between the areas and also showed that climate warming exacerbated the seasonal variability of polyphenols, culminating in a destabilization of the carbon cycle. A negative relationship between polyphenols and phenoloxidases was recorded in controls and climate treatments suggesting an inhibitory effect of phenolics on phenoloxidases. Any significant decrease of phenolics through repeatedly elevated temperature would greatly impact the ecosystem functioning and carbon cycle through an alteration of the interaction of polyphenols with microbial communities and the production of extracellular enzymes. Our climate treatments did not have the same impact along the fen-bog gradient and suggested that not all the peatland habitats would respond similarly to climate forcing

Resident CD11b(+)Ly6C(-) Lung Dendritic Cells Are Responsible for Allergic Airway Sensitization to House Dust Mite in Mice.

peer reviewedConventional dendritic cells (DCs) are considered to be the prime initiators of airway allergy. Yet, it remains unclear whether specific DC subsets are preferentially involved in allergic airway sensitization. Here, we systematically assessed the respective pro-allergic potential of individually sorted lung DC subsets isolated from house dust mite antigen (HDM)-treated donor mice, following transfer to naive recipients. Transfer of lung CD11c(+)CD11b(+) DCs, but not CD11c(+)CD11b(-)CD103(+) DCs, was sufficient to prime airway allergy. The CD11c(+)CD11b(+) DC subpopulation was composed of CD11c(+)CD11b(+)Ly6C(+) inflammatory monocyte-derived cells, whose numbers increase in the lungs following HDM exposure, and of CD11c(+)CD11b(+)Ly6C(-) DCs, which remain stable. Counterintuitively, only CD11c(+)CD11b(+)Ly6C(-) DCs, and not CD11c(+)CD11b(+)Ly6C(+) DCs, were able to convey antigen to the lymph nodes and induce adaptive T cell responses and subsequent airway allergy. Our results thus support that lung resident non-inflammatory CD11c(+)CD11b(+)Ly6C(-) DCs are the essential inducers of allergic airway sensitization to the common aeroallergen HDM in mice

Recent developments on micrometric fission chambers for high neutron fluxes

ISBN 9781424452071International audiencewith the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world