Personnaliser le traitement multi-risques du patient diabétique de type 2 : quelles cibles viser?

Conference (2011, December 13)

17-O-Actetyl-10-hydroxycorynantheol, a selective antiplasmodial alkaloid isolated from Strychnos usambarensis leaves

Conference (2011, December 13)

In the course of our investigations on Strychnos usambarensis leaves in order to isolate isostrychnopentamine, the main alkaloid responsible for the antiplasmodial activity of the plant, a new tertiary ... [more ▼]

In the course of our investigations on Strychnos usambarensis leaves in order to isolate isostrychnopentamine, the main alkaloid responsible for the antiplasmodial activity of the plant, a new tertiary indolic alkaloid has been isolated: 17-O-acetyl, 10-hydroxycorynantheol 1. Its structure was determined by means of spectroscopic and spectrometric methods such as UV, IR, CD, NMR and ESI-MS. 17-O-acetyl, 10-hydroxycorynantheol 1 is one of the most active monomeric indole alkaloid known to date showing an in vitro activity against Plasmodium falciparum close to 5 µM and a high selectivity. [less ▲]

Marx et la division du travail

Conference given outside the academic context (2011)

Astrophysical parameters and multiplicity of massive stars: a mathematical approach

Doctoral thesis (2011)

Often quoted for their crucial role in the ecology of galaxies, massive stars remain mysterious. The exact process leading to their formation, their stability or their stellar winds are so many questions ... [more ▼]

Often quoted for their crucial role in the ecology of galaxies, massive stars remain mysterious. The exact process leading to their formation, their stability or their stellar winds are so many questions which are still unanswered. Since the lifetime of these objects is too short to allow them to move far away from their birth places, the large majority of massive stars are located in young open clusters or in OB associations. The observations of massive stars in these locations thus provide with promising information on their formation mechanisms. One of the most interesting properties, in this context, is their multiplicity. Indeed, the proportion of multiple systems, the values of orbital periods, of eccentricities, or of mass ratios are parameters directly linked to the formation mechanism and to the dynamical interactions occurring during the earliest stages of their existence. Moreover, constraining this multiplicity with a sufficient accuracy allows to obtain a better determination of the nature and physical parameters of massive stars. The present work is devoted to the study of the O star populations located in the young open cluster NGC2244 and in the surrounding Mon OB2 association as well as in several OB associations of the Cygnus complex. We establish not only the multiplicity of about thirty stars but also their fundamental parameters such as their masses or their N content. However, the complexity of observed spectra of multiple systems makes these objects difficult to investigate. Their analysis thus requires the development and the utilization of mathematical tools such as the "disentangling" which allows to separate the spectra of the components from the observed ones or such as the Doppler tomography which aims at mapping the wind interactions seen in some binary systems. The first part of this dissertation is dedicated to the development and to the characterization of these mathematical methods whilst the second part focuses on the study of populations of massive stars. We refine the orbital and physical parameters of systems already known as multiple. In this context, the analysis of the two components of LZ Cep system reveals modified abundances for the secondary star, confirming a mass transfer from the secondary towards to primary. We also detect for the first time a third star in the HD150136 system. This object, composed of an O3, an O5.5 and an O6.5, constitutes a new test to apply these mathematical methods and thus to better constrain the physical properties of the system as well as those of each component. Moreover, we find, in the population of NGC2244, of Mon OB2 and of the Cygnus OB associations, six new binary systems and derive the orbital solutions for five of them. These results show that NGC2244 hosts only one long-period binary and none with a short period whilst four short-period and no long-period systems are detected in the Cygnus complex. This obvious lack of short-period system in NGC2244 contrasts with the O star populations in other young open clusters such as NGC6231 or IC 2944. Besides the multiplicity, the fundamental parameters such as the N content also allows us to, notably, adapt the so-called Hunter-diagram to galactic O stars. Moreover, we have obtained photometric data for six O-type stars in NGC2244 and Mon OB2 with the CoRoT satellite. These data of unprecedented quality allow us to detect the presence, in the O star light curves, of red noise which is supposed to originate from either the sub-surface convection zone, the granulation or an onset of clumping in the winds of the stars. We also highlight the existence of non-radial pulsations in the light curve of Plaskett’s Star as well as a hot spot located between the two components of that system. In addition, numerous frequencies, extracted from the CoRoT light curves, reveal, for some of the observed stars, solar-like oscillations or beta Cephei-like pulsations. This analysis thus gives a first observational constraint on the bright end of the massive star instability strip. [less ▲]

"Les langues: le coeur et la raison"

Conference (2011, December 12)

auditory sensitivity in birds: sex differences and noise impacts

Doctoral thesis (2011)

Coupure n’est pas renversement. La dialectique marxienne au prisme d’Althusser

Scientific conference (2011, December 12)

Characterization of the inhibition of metallo-β-lactamases of subclass B1 by VHHs cAbVIM4 and cAbBCII10

Poster (2011, December 10)

Singing the ‘dagong’ via the web: suffering, longings and ideals. An exploration of the everyday politics of migrant labour in South China

Conference (2011, December 10)

Since the 1980s, new forms of labour, new subjectivities and attitudes related to the market and to flexible capitalism have been more and more prized in the PRC coexisting with older strands of ... [more ▼]

Since the 1980s, new forms of labour, new subjectivities and attitudes related to the market and to flexible capitalism have been more and more prized in the PRC coexisting with older strands of narratives and cultural productions linked to Mao-era state-socialism. The process of cultural re-invention and of contention around “migrant labour” provides a particularly interesting vintage point in order to delve into the twin dynamics of rural workers’ unstable identification processes (at the individual and collective levels) and at the state project of legitimation. Within this paper, I intend to explore how the new media cultures inform and relate to the cultural politics of migrant labour in today’s China, including the shaping of new subjectivities, by examining rural workers’ use of the internet to narrate both their hometown and their experience of labour. I will look specifically at the everyday politics of rural workers’ practices of “song writing” via the internet and will delve upon the following questions: how does this practice of song writing/listening inform the politics of identity formation among rural labourers? how can one relate rural migrant workers’ song writing to the increasingly “on the ground” organized waves of labour protests in South China? I will argue that the virtual space which this practice provides a useful vintage point in order to examine how state and non-state actors can engage each other and how the Party-state is constantly re-inventing novel ways to shape its system of ideological signs. The datas used for this paper will include songs and poems by rural workers, an extensive analysis by the author of the Shenzhen mainstream written press, participant observation, in-depth interviews, and a large body of unpublished letters to the editor of several migrants’ magazines. [less ▲]

Evaluation comparative des statuts de races de poules locales : Algérie, Vietnam, Congo (RDC).

Conference (2011, December 09)