Monte Carlo simulations of metasomatic enrichment in the lithosphere and implications for the source of alkaline basalts

One hypothesis for the origin of alkaline lavas erupted on oceanic islands and in intracontinental settings is that they represent the melts of amphibole-rich veins in the lithosphere (or melts of their dehydrated equivalents if metasomatized lithosphere is recycled into the convecting mantle). Amphibole-rich veins are interpreted as cumulates produced by crystallization of low-degree melts of the underlying asthenosphere as they ascend through the lithosphere. We present the results of trace-element modelling of the formation and melting of veins formed in this way with the goal of testing this hypothesis and for predicting how variability in the formation and subsequent melting of such cumulates (and adjacent cryptically and modally metasomatized lithospheric peridotite) would be manifested in magmas generated by such a process. Because the high-pressure phase equilibria of hydrous near-solidus melts of garnet lherzolite are poorly constrained and given the likely high variability of the hypothesized accumulation and remelting processes, we used Monte Carlo techniques to estimate how uncertainties in the model parameters (e.g. the compositions of the asthenospheric sources, their trace-element contents, and their degree of melting; the modal proportions of crystallizing phases, including accessory phases, as the asthenospheric partial melts ascend and crystallize in the lithosphere; the amount of metasomatism of the peridotitic country rock; the degree of melting of the cumulates and the amount of melt derived from the metasomatized country rock) propagate through the process and manifest themselves as variability in the trace-element contents and radiogenic isotopic ratios of model vein compositions and erupted alkaline magma compositions. We then compare the results of the models with amphibole observed in lithospheric veins and with oceanic and continental alkaline magmas. While the trace-element patterns of the near-solidus peridotite melts, the initial anhydrous cumulate assemblage (clinopyroxene +/- garnet +/- olivine +/- orthopyroxene), and the modelled coexisting liquids do not match the patterns observed in alkaline lavas, our calculations show that with further crystallization and the appearance of amphibole (and accessory minerals such as rutile, ilmenite, apatite, etc.) the calculated cumulate assemblages have trace-element patterns that closely match those observed in the veins and lavas. These calculated hydrous cumulate assemblages are highly enriched in incompatible trace elements and share many similarities with the trace-element patterns of alkaline basalts observed in oceanic or continental setting such as positive Nb/La, negative Ce/Pb, and similiar slopes of the rare earth elements. By varying the proportions of trapped liquid and thus simulating the cryptic and modal metasomatism observed in peridotite that surrounds these veins, we can model the variations in Ba/Nb, Ce/Pb, and Nb/U ratios that are observed in alkaline basalts. If the isotopic compositions of the initial low-degree peridotite melts are similar to the range observed in mid-ocean ridge basalt, our model calculations produce cumulates that would have isotopic compositions similar to those observed in most alkaline ocean island basalt (OIB) and continental magmas after similar to 0 center dot 15 Gyr. However, to produce alkaline basalts with HIMU isotopic compositions requires much longer residence times (i.e. 1-2 Gyr), consistent with subduction and recycling of metasomatized lithosphere through the mantle. such as a heterogeneous asthenosphere. These modelling results support the interpretation proposed by various researchers that amphibole-bearing veins represent cumulates formed during the differentiation of a volatile-bearing low-degree peridotite melt and that these cumulates are significant components of the sources of alkaline OIB and continental magmas. The results of the forward models provide the potential for detailed tests of this class of hypotheses for the origin of alkaline magmas worldwide and for interpreting major and minor aspects of the geochemical variability of these magmas.

Travellers and substance use in Ireland: Recommendations for drug and alcohol policy

The Traveller community was traditionally protected from drug use by distinct traditional anti-drug norms and potent family networks within their ‘separateness’ from the ‘settled’ community. Estimations of Traveller substance use remain clouded due to lack of ethnic monitoring in drug reporting systems, and poor service utilization by Travellers. This article draws on a Traveller and substance use regional needs analysis in Ireland, comprising 12 Traveller focus groups and 45 interviews with key stakeholders. Drug activity in terms of both drug dealing and drug use among Travellers is increasing in recent years [Van Hout, M.C. (2009a). Substance misuse in the traveller community: A regional needs assessment. Western Regional Drug Task Force. Series 2. ISBN 978-0-9561479-2-9].   Traditional resiliency factors are dissipating in strength due to increased Traveller housing within marginalized areas experiencing drug activity and increased levels of young Travellers encountering youth drug use within school settings, by way of their attempts ‘to fit in’ and integrate with their ‘settled peers’ [Van Hout, M.C. (2009b). Irish travellers and drug use – An exploratory study. Ethnicity and Inequalities in Health and Social Care, 2(1), 42–49]. Fragmentation of Traveller culture is occurring as Travellers strive to retain their identity within the assimilation process into modern sedentarist Irish society. Treatment and outreach policies need to protect Traveller identity by reducing discriminatory experiences, promoting cultural acceptance with service staff and addressing literacy, implementing peer led approaches and offering flexible therapy modalities.This resource was contributed by The National Documentation Centre on Drug Use.

Differentiated normalization and drug transitions among rural youth in Ireland.

Prevalence surveys in Ireland indicate an increased trend of youth drug use with rural areas reporting comparable drug availability and prevalence of use in urban settings (Currie, C., Nic Gabhainn, S., Godeau, E., Roberts, C., Smith, R., & Currie, D. (Eds.). (2008). Inequalities in young people's health: HBSC international report from the 2005/2006 survey. Copenhagen: WHO Regional Office for Europe). Few studies have explored the contexts and meaning of drug use on rural youth transitions in terms of increased drug prevalence, recent influx of rural drug activity, normative tolerance of recreational drug consumption and fragmentation of traditional rural communities. Qualitative interviews were conducted with 220 young people (15–17 years), and 78 service providers in a rural area of Ireland, in order to yield contextualized narratives of their experiences of drug use and achieve a wider exploration of processes, drug transitions and realities of rural youth. The thematic analysis of the research described varied pathways, attitudes and typologies of rural youth drug use, ranging from abstinent, recreational and moderated to maturing out. The research suggests support for a ‘differentiated’ normalization theory (Shildrick, T. (2002). Young people, illicit drug use and the question of normalisation theory. Journal of Youth Studies, 5, 35–48) in terms of consumerist and normative rural youth drug use transitions in their negotiation of risk within integrating rural and urban dichotomies. In conclusion, it is recommended that drug education programmes need to situate localized rural drug taking behaviours within a wider understanding of rural community life.This resource was contributed by The National Documentation Centre on Drug Use.

Programmed cell death in Trypanosoma cruzi induced by Bothrops jararaca venom

Cells die through a programmed process or accidental death, know as apoptosis or necrosis, respectively. Bothrops jararaca is a snake whose venom inhibits the growth of Trypanosoma cruzi epimastigote forms causing mitochondrion swelling and cell death. The aim of the present work was to determine the type of death induced in epimastigotes of T. cruzi by this venom. Parasite growth was inhibited after venom treatment, and 50% growth inhibition was obtained with 10 µg/ml. Ultrastructural observations confirmed mitochondrion swelling and kinetoplast disorganization. Furthermore, cytoplasmic condensation, loss of mitochondrion membrane potential, time-dependent increase in phosphatidylserine exposure at the outer leaflet plasma membrane followed by permeabilization, activation of caspase like protein and DNA fragmentation were observed in epimastigotes throughout a 24 h period of venom treatment. Taken together, these results indicate that the stress induced in epimastigote by this venom, triggers a programmed cell death process, similar to metazoan apoptosis, which leads to parasite death.

Climate change impact on biodiversity in Switzerland: a review. Journal for Nature Conservation

A noticeable increase in mean temperature has already been observed in Switzerland and summer temperatures up to 4.8 K warmer are expected by 2090. This article reviews the observed impacts of climate change on biodiversity and consider some perspectives for the future at the national level. The following impacts are already evident for all considered taxonomic groups: elevation shifts of distribution toward mountain summits, spread of thermophilous species, colonisation by new species from warmer areas and phenological shifts. Additionally, in the driest areas, increasing droughts are affecting tree survival and fish species are suffering from warm temperatures in lowland regions. These observations are coherent with model projections, and future changes will probably follow the current trends. These changes will likely cause extinctions for alpine species (competition, loss of habitat) and lowland species (temperature or drought stress). In the very urbanised Swiss landscape, the high fragmentation of the natural ecosystems will hinder the dispersal of many species towards mountains. Moreover, disruptions in species interactions caused by individual migration rates or phenological shifts are likely to have consequences for biodiversity. Conversely, the inertia of the ecosystems (species longevity, restricted dispersal) and the local persistence of populations will probably result in lower extinction rates than expected with some models, at least in 21st century. It is thus very difficult to estimate the impact of climate change in terms of species extinctions. A greater recognition by society of the intrinsic value of biodiversity and of its importance for our existence will be essential to put in place effective mitigation measures and to safeguard a maximum number of native species.

Nonenzymatic oxidation of trienoic fatty acids contributes to reactive oxygen species management in Arabidopsis.

In higher plants such as Arabidopsis thaliana, omega-3 trienoic fatty acids (TFAs), represented mainly by alpha-linolenic acid, serve as precursors of jasmonic acid (JA), a potent lipid signal molecule essential for defense. The JA-independent roles of TFAs were investigated by comparing the TFA- and JA-deficient fatty acid desaturase triple mutant (fad3-2 fad7-2 fad8 (fad3 fad7 fad8)) with the aos (allene oxide synthase) mutant that contains TFAs but is JA-deficient. When challenged with the fungus Botrytis, resistance of the fad3 fad7 fad8 mutant was reduced when compared with the aos mutant, suggesting that TFAs play a role in cell survival independently of being the precursors of JA. An independent genetic approach using the lesion mimic mutant accelerated cell death2 (acd2-2) confirmed the importance of TFAs in containing lesion spread, which was increased in the lines in which the fad3 fad7 fad8 and acd2-2 mutations were combined when compared with the aos acd2-2 lines. Malondialdehyde, found to result from oxidative TFA fragmentation during lesion formation, was measured by gas chromatography-mass spectrometry. Its levels correlated with the survival of the tissue. Furthermore, plants lacking TFAs overproduced salicylic acid (SA), hydrogen peroxide, and transcripts encoding several SA-regulated and SA biosynthetic proteins. The data suggest a physiological role for TFAs as sinks for reactive oxygen species.

Jasmonates and related oxylipins in plant responses to pathogenesis and herbivory.

The vigorous production of oxygenated fatty acids (oxylipins) is a characteristic response to pathogenesis and herbivory, and is often accompanied by the substantial release of small and reactive lipid-fragmentation products. Some oxylipins, most notably those of the jasmonate family, have key roles as potent regulators. Recent advances have been made in understanding oxylipin-regulated signal transduction in response to attack. Much jasmonate signaling takes place via a genetically defined signal network that is linked to the ethylene, auxin, and salicylic acid signal pathways, but a second aspect of jasmonate signaling is emerging. Some jasmonates and several newly discovered cyclopentenone lipids can activate or repress gene expression through the activities of a conserved electrophilic atom group.

Socio-anthropologie et explication sociologique. Une réaction au texte de Laurence Podselver

(Résumé de l'ouvrage) Au travers d'une analyse socio-historique du rabbinat français, d'une enquête sur Sarcelles et d'un examen du mouvement néo-orthodoxe des Loubavitch, l'auteur brosse un tableau vivant du judaïsme contemporain et des modifications qui le traversent. Laurence Podselver apporte du même coup un éclairage sur les recompositions que connaît l'ensemble du champ religieux aujourd'hui: une affirmation de formes identitaires plus marquées venant se greffer sur l'axe de la sécularisation, de ses adaptations libérales et de ses reconstructions culturelles laïques

Genetic variability of Aedes aegypti in the Americas using a mitochondrial gene: evidence of multiple introductions

To analyze the genetic relatedness and phylogeographic structure of Aedes aegypti, we collected samples from 36 localities throughout the Americas (Brazil, Peru, Venezuela, Guatemala, US), three from Africa (Guinea, Senegal, Uganda), and three from Asia (Singapore, Cambodia, Tahiti). Amplification and sequencing of a fragment of the mitochondrial NADH dehydrogenase subunit 4 gene identified 20 distinct haplotypes, of which 14 are exclusive to the Americas, four to African/Asian countries, one is common to the Americas and Africa, and one to the Americas and Asia. Nested clade analysis (NCA), pairwise distribution, statistical parsimony, and maximum parsimony analyses were used to infer evolutionary and historic processes, and to estimate phylogenetic relationships among haplotypes. Two clusters were found in all the analyses. Haplotypes clustered in the two clades were separated by eight mutational steps. Phylogeographic structure detected by the NCA was consistent with distant colonization within one clade and fragmentation followed by range expansion via long distance dispersal in the other. Three percent of nucleotide divergence between these two clades is suggestive of a gene pool division that may support the hypothesis of occurrence of two subspecies of Ae. aegypti in the Americas.

The future of television : advertising, technology and the pursuit of audiences

La televisió està en crisi. Les noves tecnologies i els dispositius han fragmentat les audiències de televisió en segments més petits. En aquest informe, Marissa Gluck i Meritxell Roca Sales examinen l'explosió dels mitjans de comunicació que han impulsat aquesta fragmentació.

Induction of apoptosis in A549 pulmonary cells by two Paracoccidioides brasiliensis samples

Paracoccidioidomycosis presents a variety of clinical manifestations and Paracoccidioides brasiliensis can reach many tissues, most importantly the lungs. The ability of the pathogen to interact with host surface structures is essential to its virulence. The interaction between P. brasiliensis and epithelial cells has been studied, with particular emphasis on the induction of apoptosis. To investigate the expression of different apoptosis-inducing pathways in human A549 cells, we infected these cells with P. brasiliensis Pb18SP (subcultured) and 18R (recently isolated from cell culture and showing a high adhesion pattern) samples in vitro. The expressions of Bcl-2, Bak and caspase 3 were analysed by flow cytometry and DNA fragmentation using the TUNEL technique. Apoptosis of human A549 cells was induced by P. brasiliensis in a sample and time-dependent manner. Using an in vitro model, our data demonstrates that caspase 3, Bak, Bcl-2 and DNA fragmentation mediate P. brasiliensis-induced apoptosis in A549 cells. The overall mechanism is a complex process, which may involve several signal transduction pathways. These findings could partially explain the efficient behaviour of this fungus in promoting tissue infection and/or blood dissemination.

Analyse des réseaux sociaux appliquée à l'organisation d'événements sportifs : le cas de la World Gymnaestrada Lausanne 2011

Au cours des trente dernières années, de nombreuses villes, régions et pays, ont développé des politiques publiques d'accueil systématique d'événements sportifs. La concurrence globalisée qui en résulte demande des ressources dont les pouvoirs publics ne disposent pas nécessairement. Dès lors, la stratégie de développement par l'accueil d'événements sportifs est généralement rendue possible par un regroupement d'acteurs issus du secteur public, privé et du milieu associatif sous la forme d'une coalition. C'est à cette fragmentation de la gouvernance urbaine et au fonctionnement du réseau qui en découle que s'intéresse ce cahier. En prenant comme cas d'étude la World Gymnaestrada Lausanne 2011, il nous a été possible d'appliquer une analyse des réseaux sociaux à la coalition qui s'est formée autour de la manifestation. Cette approche, récente pour analyser les événements sportifs dans le contexte des villes européennes, nous a permis d'observer une prédominance des pouvoirs publics dans le réseau entourant la manifestation. Les observations suggèrent également que l'organisation de l'événement, et sa réussite, permet aux autorités de la ville de Lausanne de gagner en légitimité auprès des acteurs du réseau.

Miltefosine induces programmed cell death in Leishmania amazonensis promastigotes

In the current study, we evaluated the mechanism of action of miltefosine, which is the first effective and safe oral treatment for visceral leishmaniasis, in Leishmania amazonensis promastigotes. Miltefosine induced a process of programmed cell death, which was determined by the externalization of phosphatidylserine, the incorporation of propidium iodide, cell-cycle arrest at the sub-G0/G1 phase and DNA fragmentation into oligonucleosome-sized fragments. Despite the intrinsic variation that is detected in Leishmania spp, our results indicate that miltefosine causes apoptosis-like death in L. amazonensis promastigote cells using a similar process that is observed in Leishmania donovani.

La recherche biomédicale en Suisse : espace social, discours et pratiques

Cette étude porte sur la recherche biomédicale en Suisse dans une perspective interprétative. Elle s'intéresse à l'usage que font les acteurs scientifiques et institutionnels de la catégorie «biomédical», à la signification qu'ils en donnent et aux processus de structuration de la recherche biomédicale autour de ces enjeux de catégorisation. Nous avons formulé l'hypothèse que le «biomédical» pouvait être considéré comme un label, à savoir une stratégie discursive de positionnement des acteurs, ou pouvait constituer un champ, à savoir un espace social de recherche fortement structuré. Pour pouvoir vérifier la validité de ces hypothèses, trois perspectives analytiques ont été retenues: topographie, discours et pratiques. Dans un premier temps, nous avons établi une topographie de la recherche biomédicale en repérant les acteurs (et leur appartenance disciplinaire) et les institutions qui s'associent au terme «biomédical», que ce soit pour décrire des institutions ou des projets de recherche. Les résultats de cette analyse offrent une première approximation d'un espace de la recherche en donnant une image d'un domaine peu unifié. Ainsi, l'usage de la catégorie «biomédical» dans les projets des chercheurs n'est pas le fait des seuls médecins et biologistes, mais également de représentants d'autres disciplines. La physique, la chimie et les sciences de l'ingénieur occupent ainsi également une place très importante dans cet espace de recherche. Puis, dans une perspective discursive, nous avons analysé le «biomédical» non seulement comme un label, mais également comme un objet-frontière permettant d'articuler différentes significations, de produire du sens là où des univers de recherche pourraient s'opposer, ou à coordonner des politiques qui ne l'étaient pas. L'analyse des différentes définitions du «biomédical» nous a confirmé l'existence d'un espace social marqué par une grande diversité disciplinaire, toutefois articulé autour d'un coeur médical et, plus particulièrement, d'une application médicale (potentielle ou actuelle). De plus, il ne semble pas y avoir de profondes luttes pour l'établissement de limites claires au «biomédical». Finalement, nous avons étudié les différentes activités de la production des savoirs (carrières, financement, collaboration, publication, etc.). Cette analyse a permis de comprendre que la diversité des définitions et des significations que les acteurs attribuent à la catégorie «biomédical» a aussi un ancrage dans la matérialité des réseaux sociotechniques dans lesquels les chercheurs s'inscrivent. Ces éléments confirment l'idée d'une fragmentation et d'une hétérogénéité de l'espace de la recherche biomédicale. En dépit de cette fragmentation, nous avons également montré que différentes mesures et instruments d'action publique visant à organiser et réguler les pratiques des chercheurs sont mis en oeuvre. Néanmoins et paradoxalement, la recherche biomédicale ne constitue pas pour autant un objet de politique scientifique abordé par les autorités politiques, en tous les cas pas sous l'angle de la catégorie «biomédical». Ces différents niveaux d'analyse ont permis d'arriver à la conclusion que la catégorie «biomédical» n'est pas suffisamment institutionnalisée et que le degré d'interaction entre l'ensemble des chercheurs qui en font usage est trop faible pour que l'on puisse considérer le «biomédical» comme un espace social fortement organisé et structuré, à savoir un champ de la recherche biomédicale. Cela est principalement lié au fait que les acteurs ne partagent pas les mêmes définitions de ce qu'est (ou devrait être) le «biomédical», que leurs pratiques de recherche s'inscrivent dans des univers relativement séparés, et que cette diversité ne donne pas lieu à de fortes luttes pour l'imposition d'une définition légitime ou de normes d'excellence scientifiques dominantes. Par contre, les analyses ont permis de confirmer la validité du «biomédical» comme label, puisque les acteurs se servent de cette catégorie pour valoriser leurs pratiques de recherche et se positionner, même si d'autres notions ont émergé ces dernières années («translationnel», «biotech», «medtech», médecine personnalisée, etc.). On peut, in fine, considérer le «biomédical» comme un probable langage commun («objet-frontière») reposant tant sur la scientificisation du médical que sur la médicalisation des sciences («de base» et «techniques »), visant à améliorer les conditions de possibilité d'un dialogue fructueux entre chercheurs fondamentaux et cliniciens.

Major, minor, trace element, Sm-Nd and Sr isotope compositions of mafic rocks from the earliest oceanic crust of the Alpine Tethys

Recent isotopic and biochronologic dating has demonstrated that the Gets nappe contains remnants of the oldest part of the oceanic crust of the Alpine Tethys. The ophiolites are associated with deep sea sediments, platform carbonates and continental crustal elements suggesting a transitional environment between continental and oceanic crust. Therefore, the ophiolites from the Gets nappe provide the opportunity to assess the nature of mantle source and the magma evolution during the final rifting stage of the European lithosphere. Trace clement analyses of mafic rocks can he divided into two sets: (1) P, Zr and Y contents are consistent with those of mid-ocean ridge basalts and REE patterns have a P-MORB affinity. (2) P,Zr Ti and Y contents are compatible with within-plate basalts and are characterized by REE spectra similar to that of T-MORB. Both have Nd isotopic compositions similar to those of synrift magma of the Red Sea and to the Rhine Graben. The model ages are in agreement with an LREE-enriched subcontinental mantle source derived from depleted mantle 800 to 900 Ma ago. Minor, trace element and Sm-Nd compositions suggest that these rocks are basaltic relies of an earliest stage of oceanic spreading i.e. an embryonic ocean. Comparison between REE patterns, Nd and Sr isotope compositions, isotopic and biochronologic ages from different Alpine Tethys ophiolites shows that samples with enriched LREE are from the older ophiolitic suites and are relies of the embryonic ocean floor. Later phases of ocean spreading are characterized by basalts that are depleted in LREE.