Dinosaur Fossils Predict Body Temperatures

Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 °C at 12 kg to approximately 41 °C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy

SPARCS: a web server to analyze (un)structured regions in coding RNA sequences.

International audienceMore than a simple carrier of the genetic information, messenger RNA (mRNA) coding regions can also harbor functional elements that evolved to control different post-transcriptional processes, such as mRNA splicing, localization and translation. Functional elements in RNA molecules are often encoded by secondary structure elements. In this aticle, we introduce Structural Profile Assignment of RNA Coding Sequences (SPARCS), an efficient method to analyze the (secondary) structure profile of protein-coding regions in mRNAs. First, we develop a novel algorithm that enables us to sample uniformly the sequence landscape preserving the dinucleotide frequency and the encoded amino acid sequence of the input mRNA. Then, we use this algorithm to generate a set of artificial sequences that is used to estimate the Z-score of classical structural metrics such as the sum of base pairing probabilities and the base pairing entropy. Finally, we use these metrics to predict structured and unstructured regions in the input mRNA sequence. We applied our methods to study the structural profile of the ASH1 genes and recovered key structural elements. A web server implementing this discovery pipeline is available at http://csb.cs.mcgill.ca/sparcs together with the source code of the sampling algorithm

L'argent, la vie, la mort : les recherches sociales de Louis-René Villermé sur la mortalité différentielle selon le revenu (1822-1830)

Louis-René Villermé, by his computations in political economy performed under the aegis of the Royal Academy of Medicine, based on administrative data, overthrows a timeless and fundamental topos of universal culture (money is powerless against death). Villermé establishes instead the existence of a direct relationship between ease (hence money) and longevity, and, naturally, of an inverse relationship between this same ease and mortality. A deep cultural revolution is at stake here concerning the perception of the relationships between money, life and death. The paper raises afterwards the question of the reasons why these daring results of political arithmetic of the years 1825 have only been accepted with a certain reticence by the official depositaries of the strictly statistical tradition of the Académie Royale des Sciences, i.e. the jury for the prize of statistics Auget de Montyon, and principally its referee Coquebert de Montbret.Louis-René Villermé, par ses calculs d'arithmétique politique au nom de l'Académie Royale de Médecine, sur des données administratives, renverse un topos immémorial et fondamental de la culture universelle (l'impuissance de l'argent face à la mort). Villermé établit au contraire l'existence d'une relation directe entre l'aisance (donc l'argent) et la longévité, et naturellement, d'une relation inverse entre cette même aisance (donc toujours l'argent) et la mortalité. C'est bien d'une révolution culturelle profonde qu'il s'agit quant à la perception des rapports respectifs de l'argent, de la vie et de la mort. On s'interrogera ensuite sur les raisons pour lesquelles ces résultats pour le moins audacieux de l'arithmétique politique des années 1825 n'ont été accueillis qu'avec une certaine réticence - et même une réticence certaine - par les dépositaires officiels de la tradition strictement statistique de l'Académie Royale des Sciences, c'est-à-dire le jury du prix de statistique Auget de Montyon, principalement, le rapporteur Coquebert de Montbret

The Formation of the Bicoid Morphogen Gradient Requires Protein Movement from Anteriorly Localized mRNA

New quantitative data show that the Bicoid morphogen gradient is generated from a dynamic localized source and that protein gradient formation requires protein movement along the anterior-posterior axis

Gene profiling of the erythro- and megakaryoblastic leukaemias induced by the Graffi murine retrovirus

<p>Abstract</p> <p>Background</p> <p>Acute erythro- and megakaryoblastic leukaemias are associated with very poor prognoses and the mechanism of blastic transformation is insufficiently elucidated. The murine Graffi leukaemia retrovirus induces erythro- and megakaryoblastic leukaemias when inoculated into NFS mice and represents a good model to study these leukaemias.</p> <p>Methods</p> <p>To expand our understanding of genes specific to these leukaemias, we compared gene expression profiles, measured by microarray and RT-PCR, of all leukaemia types induced by this virus.</p> <p>Results</p> <p>The transcriptome level changes, present between the different leukaemias, led to the identification of specific cancerous signatures. We reported numerous genes that may be potential oncogenes, may have a function related to erythropoiesis or megakaryopoiesis or have a poorly elucidated physiological role. The expression pattern of these genes has been further tested by RT-PCR in different samples, in a Friend erythroleukaemic model and in human leukaemic cell lines.</p> <p>We also screened the megakaryoblastic leukaemias for viral integrations and identified genes targeted by these integrations and potentially implicated in the onset of the disease.</p> <p>Conclusions</p> <p>Taken as a whole, the data obtained from this global gene profiling experiment have provided a detailed characterization of Graffi virus induced erythro- and megakaryoblastic leukaemias with many genes reported specific to the transcriptome of these leukaemias for the first time.</p

Modelled spatial distribution of marine fish and projected modifications in the North Atlantic Ocean.

International audienceThe objectives of this work were to examine the past, current and potential influence of global climate change on the spatial distribution of some commercially exploited fish and to evaluate a recently proposed new ecological niche model (ENM) called nonparametric probabilistic ecological niche model (NPPEN). This new technique is based on a modified version of the test called Multiple Response Permutation Procedure (MRPP) using the generalized Mahalanobis distance. The technique was applied in the extratropical regions of the North Atlantic Ocean on eight commercially exploited fish species using three environmental parameters (sea surface temperature, bathymetry and sea surface salinity). The numerical procedure and the model allowed a better characterization of the niche (sensu Hutchinson) and an improved modelling of the spatial distribution of the species. Furthermore, the technique appeared to be robust to incomplete or bimodal training sets. Despite some potential limitations related to the choice of the climatic scenarios (A2 and B2), the type of physical model (ECHAM 4) and the absence of consideration of biotic interactions, modelled changes in species distribution explained some current observed shifts in dominance that occurred in the North Atlantic sector, and particularly in the North Sea. Although projected changes suggest a poleward movement of species, our results indicate that some species may not be able to track their climatic envelope and that climate change may have a prominent influence on fish distribution during this century. The phenomenon is likely to trigger locally major changes in the dominance of species with likely implications for socio-economical systems. In this way, ENMs might provide a new management tool against which changes in the resource might be better anticipated

La démocratie participative comme mécanisme de production d'un sous-système d'élites de la participation: le cas des agriculteurs familiaux dans le programme de développement territorial rural durable au Brésil, territoire d'Aguas Emendadas

National audienceCet article se propose d'étudier la participation des agriculteurs familiaux au "développement rural durable" dans une configuration territoriale impliquant une action publique multi-niveau. Guidés par une posture scientifique qui tente de dépasser l'analyse réifiée des instances participatives, nous choisissons de concilier la sociologie de l'action publique territorialisée avec celle des trajectoires militantes et des répertoires d'action collective des participants. Au travers de l'exemple choisi, nous cherchons à comprendre les effets que peut induire la participation d'une catégorie traditionnellement exclue de l'élaboration des politiques publiques sur l'évolution des rapports historiques de pouvoir et de domination politique au Brésil. Nous questionnons ainsi la classique dichotomie entre l'acteur et le système en analysant l'interaction entre les règles du jeu des arènes participatives et les rapports de pouvoir du policy making territorialisé. La première partie décrit les spécificités du dispositif territorial et ses récentes évolutions. Elle révèle qu'au vu des intentions initiales, la configuration du programme territorial repose sur une contradiction. L'espace prévu pour la catégorie de l'agriculture familiale est limité : d'abord parce que ses représentants partagent la décision avec des acteurs mieux armés en termes de ressources, puis, parce que les structures fédérales restent prégnantes dans le circuit décisionnel de l'action publique territoriale. Pour autant, ceci n'a pas empêché que se constitue une "coalition" de représentants de l'agriculture familiale formée par un groupe de leaders des communautés d'agriculteurs qui ont investi et monopolisé le dispositif participatif. La seconde partie met à jour les trajectoires militantes et les répertoires d'actions collectives de ces "élites de la participation" qui forment le "noyau dur" des instances participatives. La troisième partie renseigne sur le "militantisme institutionnel" de ces participants qui a été acquis au travers de leur longévité dans l'espace participatif. Cette trajectoire présente par ailleurs les contours d'un processus de "spécialisation" qui contribue à institutionnaliser la "domination" de ces leaders qui revendiquent le monopole légitime de la représentation des communautés des agriculteurs familiaux. Le cadrage des projets de développement territorial rural durable depuis leur élaboration jusqu'à leur mise en oeuvre reste néanmoins dominé par l'expertise dont les techniciens restent les principaux détenteurs

The participation of family farmers in the territorial sustainable rural development program in Brazil: trajectories, projects, networks/coalitions (Territory Aguas Emendadas)

International audienceThe communication's case study deals with the trajectories of Brazilian family farmers of Aguas Emendadas territory (Federal District) in participative procedures and the effects of this participation device proposed by Agrarian Development Ministry among the PDSTR (Sustainable Development Program of Rural territories). The social and political resources distribute very unevenly the chances of family farmers to integrate and stay in participation procedures. The legitimacy of the participants of the rural "civil society" is based on three main elements: their capacity to represent farmers' communities; their institutional activism: negotiations and formalization with public administration technicians and officials in order to select "good" policy projects; the dominion of the expertise. However, we observe the appearance of sector-based "elite of the participation" among family farmer. To conclude, this participative policy making constitutes an hybridization between several models of public action and between several political practices of participation

A new method for estimating locomotion type in large ground birds

Estimating the locomotion type of fossil ground birds is necessary for a better understanding of their ecology. Until now, only one method has allowed us to estimate the locomotion of fossil ground birds, but its application is complicated in the majority of fossil cases because it requires data from the three bones from the same hindlimb of one individual. Here, we propose a new method using only the maximum length and minimum width of the tarsometatarsus to estimate the locomotion of these fossil birds. This method is easy to apply and better distinguishes the intermediate cases between graviportal (walking) and cursorial (running) birds. This study shows that the species of large ground birds of the families Gastornithidae and Brontornithidae were all graviportal, probably because of their large body mass. More unexpectedly, it also shows that some Phorusrhacidae (e.g. Paraphysornis), usually described as cursorial birds, were in fact graviportal, probably because of their considerable body mass. All these new data about locomotion provide a better understanding of the ecology of fossil ground birds