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Zimmer M.,EPHE Paris
European Journal of Anaesthesiology | Year: 2014

The direct application of volatile anaesthetic and the application of intense cold to traumatic injuries and surgical sites were important steps in 18th and 19th century anaesthesia. Local tissue temperature could be brought down by the application of ice and salt by the surgeon. Techniques used topical applications of chloroform, Dutch Oil, amyl hydrate, the vaporisation of nebulised ether, methylene and ethylene chloride applied by spray or fumigation and vaginal douche with carbonic acid gas. Mastering the projection of cold was extremely difficult. Keeping the aperture of the device used for the spraying of anaesthetic liquids clear of obstruction became a major challenge for instrument makers. To improve the precision of the jet, a different system of nozzles had to be invented. Nineteenth century medical practitioners were able to call on general anaesthesia, but some individuals and specific indications such as minor surgery called for an alternative approach. The introduction of cocaine in 1884 completely changed common practice. Source

Veuille M.,EPHE Paris
Comptes Rendus - Biologies | Year: 2010

Darwin's book on the Descent of Man and Selection in Relation to Sex (1871) is often viewed as the continuation of The Origin of Species published 12 years earlier (1859), both because of the implicit parallelism between natural selection and sexual selection, and because Darwin himself presents the book as developing a subject (man) which he intentionally omitted in the Origin. But the Descent can also be viewed as the continuation of his book on Variation published three years earlier (1868). Firstly because Darwin's hypothesis of pangenesis links the selection process to the origin of variation through use and disuse, an idea underlying his speculations on the origin of moral sense in humans. Second because like the action of the horticulturist on his domestic crops, sexual selection exerted by one sex on the other sex can develop fancy traits that are not easily accounted for by their utility to the selected organism itself, such as artistic taste, pride, courage, and the morphological differences between human populations. These traits are difficult to reconcile with pangenesis. They add up to other contradictions of the book possibly resulting from Darwin's erroneous inference about the mechanism of inheritance, like those on the determination of sex-ratio, or the confusion between individual adaptation and the advantage to the species. These inconsistencies inaugurate a weakening of the Darwinian message, which will last 50 years after his death. They contributed to the neglect of sexual selection for a century. Darwin however maintained a logical distinction between evolutionary mechanisms and hereditary mechanisms, and an epistemological distinction between evolutionary theory and Pangenesis hypothesis. In the modern context of Mendelian genetics, Darwin's sexual selection retrospectively appears as luminous an idea in its pure principle as natural selection, even though the mechanisms governing the evolution of sexual choice in animals remain largely unresolved. © 2009 Académie des sciences. Source

Cronin A.L.,University Pierre and Marie Curie | Molet M.,University Pierre and Marie Curie | Doums C.,University Pierre and Marie Curie | Doums C.,EPHE Paris | And 2 more authors.
Annual Review of Entomology | Year: 2013

The spectacular success of eusocial insects can be attributed to their sophisticated cooperation, yet cooperation is conspicuously absent during colony foundation when queens are alone. Selection against this solitary stage has led to a dramatically different strategy in thousands of eusocial insect species in which colonies are started by groups of nestmates and the benefits of sociality are retained continuously. Dependent colony foundation (DCF) evolved recurrently multiple times across the ants, bees, and wasps, though its prevalence in termites remains unclear. We review adaptations at both the colony level (reproductive investment shifts from sexuals to workers) and the individual level (wingless queens evolve in ants), and other consequences for life history (invasiveness, parasite transmission). Although few studies have focused on DCF, the accumulated data from anecdotal reports, supported by indirect information including morphology, population genetics, and colony demographics, make it clear that this strategy is more diverse and widespread than is usually recognized. © 2013 by Annual Reviews. All rights reserved. Source

Santos X.,University of Porto | Cheylan M.,EPHE Paris
Biological Conservation | Year: 2013

Wildfires are common disturbances that have a major impact on ecosystems. Recent decades have seen an increase in fire frequency and extension due to the combined effects of climate change and land-use history. We studied the taxonomic and functional response of a reptile assemblage to repeated fires in southern France to understand shifts in dominant species and diversity, as well as the mechanisms that underlie responses according to functional traits of species. In the spring of 2010, we sampled reptiles in areas with three types of fire regime: unburned, burned once (2003) and burned 4-5 times (last fire in 2003) along a fire history of 51-years period. With this field sampling design, we examined the intermediate disturbance hypothesis and the habitat accommodation model of succession as methods to predict reptile responses to natural fire regimes. We also compared habitat structure at the study area between 1944 and 2006 to certify that repeated-fire regimes have modified the habitat for reptiles. The comparison of the habitat structure between both periods demonstrated that repeated-fire regimes modified the landscape from a homogeneous sparse forest to a contrasted heterogeneous mixture of scrubland and dense forest. We found a loss of reptile diversity after one and multiple fires, a result that contradicts the intermediate disturbance hypothesis. Reptile composition differed among the three fire regimes: there was a shift in dominant species and a reduction of beta diversity related to an increase in the number of fires. We also observed a functional response to repeated fires, with an increased frequency of insectivorous reptiles, which live in open areas, are specialists in their ecological niche, and have a short lifespan. These results suggest that reptile replacement according to fire regime accounts for a habitat accommodation model following particular traits of species. Our study indicated that areas subjected to repeated fires have a more strictly Mediterranean reptile assemblage than unburned areas, due to the ability of Mediterranean species to survive thermal environments in open (burned) areas. At a regional scale, changes in dominant species between unburned and repeatedly burned areas might be an argument for maintaining a patchwork of areas burned at variable intervals. However, the increase in fire frequency and extension suggests a future scenario of extinction for species negatively impacted by fire, such as the endangered Hermann's tortoise Testudo hermanni, for which the study area is home to one of the last native populations in the western Mediterranean. © 2013 Elsevier Ltd. Source

The increasing popularity of stem cells in life science research has at least two major causes. On one hand, the study of stem cells may provide insights into one of the major secrets of biology: the mechanisms of cell differentiation. On the other hand, stem cells are potentially promising tools for regenerative therapy. The understanding of how environmental stimuli are translated into phenotypic differentiation through gene expression changes and how the same stimuli at the same time may perturb the normal process of cellular differentiation, growth and maintenance is a central issue for fundamental research but is also essential for the development of efficient and safe procedures for therapeutic use. This article assembles the known facts, as pieces of a puzzle, into a coherent picture around the idea of why stem cells are so sensitive to their culture environment and what practical consequences this implies. © 2013 Future Medicine Ltd. Source

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