Individuality and consistency in foraging behaviour of the Bumblebee Bombus terrestris

PhDMany vertebrates and a few invertebrates are known to show individual-specific consistency in their behaviour across time and situations, sometimes in ways that can be paralleled with human personality. Despite their relatively small brains, bees show remarkable cognitive abilities. It is therefore not unreasonable to speculate that, as other animals with such cognitive abilities, they too would be able to show some form of animal personality. The first three chapters of this work are theoretical and discuss relevant concepts and controversies in the field of animal personality. Chapter 4 explored the possibility of individual bees differing in their ability to learn to associate stimuli with reward. While some bees learned to differentiate between two stimuli with a high degree of accuracy, others made frequent mistakes, independently of the modality or dimension of the stimuli considered. Bees therefore appeared to differ individually in their ability to discriminate between stimuli. Chapter 5 of this work aimed at answering the question of whether individual bees consistently differ in their behaviour, which is a prerequisite to establishing the existence of personality in any animal. Individual bees’ response to novelty (neophobianeophilia) was found to be relatively predictable within a short time scale but not on the long term. Neophobia-neophilia is therefore an episodic personality trait. Chapter 6 was concerned with individual responses to a simulated predation threat. Individual bees were found to vary widely, both qualitatively and quantitatively. These responses were consistent through time and so were other features of their foraging behaviours. Taken together, my findings provide an insight into individual variations in foraging behaviour in the bumblebee Bombus terrestris and represent good evidence for the existence of individual consistency, thus paving the way for further research into personality traits in this species

L’autodétermination dans la mise en place de projet: regards croisés des animateurs socioculturels et des éducateurs sociaux sur leur partique auprès des personnes souffrant de troubles psychiques

Cette recherche exploratoire porte sur le thème de l’autodétermination dans la mise en place de projet avec des personnes qui souffrent de troubles psychiques. Nous avons axé notre démarche sous l’angle du travailleur social et plus particulièrement des animateurs socioculturels et des éducateurs sociaux. Le but de notre recherche est de mettre en lumière la manière dont les professionnels cités ci-dessus estiment favoriser l’autodétermination des personnes souffrant de troubles psychiques dans la mise en place de projet. La partie théorique présente tout d’abord des notions liées à la personne accompagnée telles que le concept de maladie psychique et d’autodétermination. Elle traite aussi de thématiques liées aux animateurs socioculturels et aux éducateurs sociaux telles que le concept de pratique professionnelle, de projet (outil commun aux deux professions) et d’institution. Des notions juridiques qui concernent l’autodétermination sont également abordées. Il s’agit de la capacité de discernement ainsi que des mesures du nouveau droit de l’adulte. La partie pratique de ce travail est basée sur une approche qualitative. Quatre entretiens d’animateurs socioculturels et quatre entretiens d’éducateurs sociaux travaillant dans des institutions qui accueillent des personnes ayant des troubles psychiques ont été réalisés. Ces derniers ont ensuite été croisés dans la partie analytique. Les résultats mettent en évidence la manière dont les professionnels estiment favoriser l’autodétermination des personnes à travers le projet. Ils exposent leurs limites et difficultés dans cette démarche qui sont liées à la personne accompagnée ainsi qu’à son environnement. Il en ressort que les animateurs socioculturels et les éducateurs sociaux ont des pratiques différentes et complémentaires pour favoriser l’autodétermination à travers un projet. Le cadre institutionnel peut représenter un facilitateur ou un frein dans la favorisation de l’autodétermination des personnes ayant des troubles psychiques. L’issue de ce travail met en lumière diverses pistes d’action qui constituent, selon nous, des outils pour les professionnels et leur pratique. Nous avons développé une perspective liée à la culture institutionnelle, une seconde en lien avec les pratiques du professionnel et une dernière en lien avec la personne et son environnement

Scientific evidence on how organic food and farming contributes to sustainable food security

This briefing aims to summarise the most relevant recent scientific publications that critically assess the productivity and sustainability of organic farming methods. The rapid increase in the quantity of scientific literature on this topic reflects the growing importance of the sector as well as the need for accurate data and analysis to inform policy makers. There are currently 2.7 million organic-certified farmers (of which 350.000 are in Europe) who have committed to sustainable farming practices. Can organic food and farming be upscaled in order to contribute to sustainable food system and food security

Adipose Tissue Is a Neglected Viral Reservoir and an Inflammatory Site during Chronic HIV and SIV Infection

International audienceTwo of the crucial aspects of human immunodeficiency virus (HIV) infection are (i) viral persistence in reservoirs (precluding viral eradication) and (ii) chronic inflammation (directly associated with all-cause morbidities in antiretroviral therapy (ART)-controlled HIV-infected patients). The objective of the present study was to assess the potential involvement of adipose tissue in these two aspects. Adipose tissue is composed of adipocytes and the stromal vascular fraction (SVF); the latter comprises immune cells such as CD4+ T cells and macrophages (both of which are important target cells for HIV). The inflammatory potential of adipose tissue has been extensively described in the context of obesity. During HIV infection, the inflammatory profile of adipose tissue has been revealed by the occurrence of lipodystrophies (primarily related to ART). Data on the impact of HIV on the SVF (especially in individuals not receiving ART) are scarce. We first analyzed the impact of simian immunodeficiency virus (SIV) infection on abdominal subcutaneous and visceral adipose tissues in SIVmac251 infected macaques and found that both adipocytes and adipose tissue immune cells were affected. The adipocyte density was elevated, and adipose tissue immune cells presented enhanced immune activation and/or inflammatory profiles. We detected cell-associated SIV DNA and RNA in the SVF and in sorted CD4+ T cells and macrophages from adipose tissue. We demonstrated that SVF cells (including CD4+ T cells) are infected in ART-controlled HIV-infected patients. Importantly, the production of HIV RNA was detected by in situ hybridization, and after the in vitro reactivation of sorted CD4+ T cells from adipose tissue. We thus identified adipose tissue as a crucial cofactor in both viral persistence and chronic immune activation/inflammation during HIV infection. These observations open up new therapeutic strategies for limiting the size of the viral reservoir and decreasing low-grade chronic inflammation via the modulation of adipose tissue-related pathway

Inflammatory control in AIDS-resistant non human primates

International audienceAfrican non human primates are natural hosts of SIV. The infection is non-pathogenic despite plasma viral load levels similar to those in HIV-1 infected humans and SIVmac-infected macaques (MAC) progressing towards AIDS. The most striking difference between non-pathogenic SIV and pathogenic HIV-1/SIVmac infections is the lack of chronic T cell activation in natural hosts. In HIV and SIVmac infections, chronic T cell activation is known to drive CD4+T cell depletion. Intense research efforts are worldwide put on the search of the mechanisms that can control chronic T cell activation in HIV/SIV infections. Innate immune responses play a determinant role in the regulation of T cell activation profiles. Type I interferons (IFN-I) are part of the first-wave response of the innate immune system in viral infections. We compared the IFN-I responses between pathogenic (MAC) and non-pathogenic SIV infections (African Green monkey, AGM) at the level of blood and lymph nodes (LN) during the early and chronic stage of infection. During the acute SIVagm infection, we detected high amounts of IFN-α in the plasma of AGMs, although the mean levels at the peak were three times lower than in MAC. The microarray data revealed a rapid and strong up-regulation of type I Interferon-Stimulated Genes (ISG) in AGMs during acute SIVagm infection. ISGs denote the in vivo activity of IFN-I. Using a functional assay, we demonstrated that low IFN-α concentrations (50 times lower than the IFN-α levels in plasma at the peak) were sufficient to induce strong ISG responses in AGM and MAC cells. Surprisingly, our direct comparison of blood and LNs showed that ISG induction was broader in blood of AGMs than in MAC, while in LN, it was the contrary. Thus, in AGMs, less ISG were induced in LNs as compared to MAC already during the acute phase of infection. Moreover, our tight kinetic analysis showed that this ISG expression was efficiently controlled after day 28 post-infection in AGMs, while in MAC the ISGs expression remained uncontrolled. Finally, we identified genes that were differentially expressed between the two species and which might be involved in the discriminating responses. Altogether, this shows that AGMs are capable to mount a well coordinated and efficient regulative response to innate immune activation

One-loop analysis of the reaction pi N to pi pi N

Single pion production off nucleons is studied in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. Using total and some older differential cross section data to pin down the low-energy constants, most of the recent differential cross sections and angular correlation functions can be described as well as total cross sections at higher energies. We show that the contributions from the one loop graphs are essentially negligible and that the dominant terms at second and third order are related to pion-nucleon scattering graphs with one pion added. We also discuss the possibility of extracting the pion-pion S-wave scattering lengths from the unpolarized data.Comment: 57 pp, LaTeX file, 13 figures (uses epsf

Exploiting the 2-Amino-1,3,4-thiadiazole Scaffold To Inhibit <i>Trypanosoma brucei </i>Pteridine Reductase in Support of Early-Stage Drug Discovery

Pteridine reductase-1 (PTR1) is a promising drug target for the treatment of trypanosomiasis. We investigated the potential of a previously identified class of thiadiazole inhibitors of Leishmania major PTR1 for activity against Trypanosoma brucei (Tb). We solved crystal structures of several TbPTR1-inhibitor complexes to guide the structure-based design of new thiadiazole derivatives. Subsequent synthesis and enzyme- and cell-based assays confirm new, mid-micromolar inhibitors of TbPTR1 with low toxicity. In particular, compound 4m, a biphenyl-thiadiazole-2,5-diamine with IC50 = 16 μM, was able to potentiate the antitrypanosomal activity of the dihydrofolate reductase inhibitor methotrexate (MTX) with a 4.1-fold decrease of the EC50 value. In addition, the antiparasitic activity of the combination of 4m and MTX was reversed by addition of folic acid. By adopting an efficient hit discovery platform, we demonstrate, using the 2-amino-1,3,4-thiadiazole scaffold, how a promising tool for the development of anti-T. brucei agents can be obtained

GENESIS: Co-location of Geodetic Techniques in Space

Improving and homogenizing time and space reference systems on Earth and, more directly, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1mm and a long-term stability of 0.1mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation for predicting natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities which has enunciated geodesy requirements for Earth sciences. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, proposed as a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this white paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology.Comment: 31 pages, 9 figures, submitted to Earth, Planets and Space (EPS