Controlling the cold collision shift in high precision atomic interferometry

We present here a new method based on a transfer of population by adiabatic passage that allows to prepare cold atomic samples with a well defined ratio of atomic density and atom number. This method is used to perform a measurement of the cold collision frequency shift in a laser cooled cesium clock at the percent level, which makes the evaluation of the cesium fountains accuracy at the $10^{-16}$ level realistic. With an improved set-up, the adiabatic passage would allow measurements of atom number-dependent phase shifts at the $10^{-3}$ level in high precision experiments.Comment: 4 pages, 3 figures, 2 table

[Protocol] Visual feedback of the individual's medical imaging results for changing health behaviours in clinical and non-clinical populations

Primary objective To assess the extent to which presentation to the individual of images of their own body created during medical imaging procedures increases or decreases health behaviours such as: 1. dietary fat intake; 2. physical activity levels; 3. smoking; 4. alcohol use; 5. damaging exposure to sunlight or other sources of ultraviolet radiation. This will be considered in comparison to the impact of communicating the same findings in a way which does not involve showing the person the source images derived from the imaging procedure (such as solely through oral feedback, or a written report). Secondary objective A secondary objective is to determine the impact of this feedback on consumers': 1. understanding of the relevant condition and of the risk information they have been given; 2. perceived severity and risk of disease; 3. perceived control over the disease risk; 4. perceived effectiveness of the risk-reducing behaviour; 5. emotional response, including general anxiety and condition-specific worry

What makes a host profitable? Parasites balance host nutritive resources against immunity

Numerous host qualities can modulate parasite fitness, and among these, host nutritive resources and immunity are of prime importance. Indeed, parasite fitness increases with the amount of nutritive resources extracted from the host body and decreases with host immune response. To maximize fitness, parasites have therefore to balance these two host components. Yet, because host nutritive resources and immunity both increase with host body condition, it is unclear whether parasites perform better on hosts in prime, intermediate, or poor condition. We investigated blood meal size and survival of the ectoparasitic louse fly Crataerina melbae in relation to body condition and cutaneous immune response of their Alpine swift (Apus melba) nestling hosts. Louse flies took a smaller blood meal and lived a shorter period of time when feeding on nestlings that were experimentally food deprived or had their cutaneous immune response boosted with methionine. Consistent with these results, louse fly survival was the highest when feeding on nonexperimental nestlings in intermediate body condition. Our findings emphasize that although hosts in poor condition had a reduced immunocompetence, parasites may have avoided them because individuals in poor condition did not provide adequate resources. These findings highlight the fact that giving host immunocompetence primary consideration can result in a biased appraisal of host-parasite interactions

Testing Lorentz Invariance using Zeeman Transitions in Atomic Fountains

Lorentz Invariance (LI) is the founding postulate of Einstein's 1905 theory of relativity, and therefore at the heart of all accepted theories of physics. It characterizes the invariance of the laws of physics in inertial frames under changes of velocity or orientation. This central role, and indications from unification theories hinting toward a possible LI violation, have motivated tremendous experimental efforts to test LI. A comprehensive theoretical framework to describe violations of LI has been developed over the last decade: the Lorentz violating Standard Model Extension (SME). It allows a characterization of LI violations in all fields of present day physics using a large (but finite) set of parameters which are all zero when LI is satisfied. All classical tests (e.g. Michelson-Morley or Kennedy-Thorndike experiments) can be analyzed in the SME, but it also allows the conception of new types of experiments, not thought of previously. We have carried out such a conceptually new LI test, by comparing particular atomic transitions (particular orientations of the involved nuclear spins) in the $^{133}$Cs atom using a cold atomic fountain clock. This allows us to test LI in a previously largely unexplored region of the SME parameter space, corresponding to first measurements of four proton parameters and an improvement by 11 and 12 orders of magnitude on the determination of four others. In spite of the attained accuracies, and of having extended the search into a new region of the SME, we still find no indication of LI violation.Comment: 5 pages, in proceedings of the IEEE-FCS, (2005). New version with typo in Tab. III correcte

Selective disappearance of individuals with high levels of glycated haemoglobin in a free-living bird

This work was supported by the ANR (ANR-06-JCJC0082 to B.D.), the CNRS (PEPS INEE and PICS France–Switzerland to B.D.), the French Ministe`re de l’Enseignement Supe´rieur et de la Recherche (PhD fellowship to C.R.), the Re´gion Rhoˆne-Alpes (Explora’doc mobility grant to C.R.), the University of Aberdeen (stipend to C.R.), the L’Ore´al Foundation-UNESCO ‘For Women in Science’ program (fellowship to C.R.) and the Rectors’ Conference of the Swiss Universities (grant to C.R. and P.B.).Peer reviewedPostprin

Black Spots: Roads and Risk in Rural Kenya

This dissertation examines “post-agrarian” transformations in Kenyan rural areas. But where rural transformation is usually written as a story about land, Black Spots is a story about roads. Kenya’s massive investment in roads infrastructure over the last decade has intersected with the decline in smallholder agriculture in such a way that, for many rural residents, fortunes are now imagined on the road rather than on the land. Roadside trade, transport, and even salvage from crashes provide supplementary livings for rural populations facing declining agricultural opportunities. The dissertation argues that in the context of austerity policies and rural abandonment, road work and its “fast money” not only expose roadside residents to physical danger, but also entrench entrepreneurial risk ideology into local imaginaries. With the road accident as a lens illuminating a wider landscape of rural hazard, the dissertation shows how rural residents refashion relationships to land, work, technology, and loss in high-risk environments. At the same time, it demonstrates the limits of “risk”—that is, a calculated engagement with potential loss, conducted in the interest of profit—as a framework for managing contingency. In this sense, Black Spots is both an ethnography of risk and of what risk fails to capture. It tracks how rural residents learn to engage bodily and economic hazard and to understand it as risk; how they coordinate the disparate temporalities and technologies of life on the road and life on the land; and how they withstand loss when these attempts do not go as planned. The dissertation thus advances two parallel concerns: on the one hand, it demonstrates how economic practice is at once bodily and reasoned. On the other, it considers how experiences of and ideas about contingency are shaped in relation to shifting economic, social, and infrastructural possibilities

Les comportements face au VIH/sida des hommes qui ont des rapports sexuelles avec des hommes : Enquête Gaysurvey 2014

Depuis 1987, Gaysurvey est une enquête menée périodiquement en Suisse parmi les hommes qui ont des relations sexuelles avec des hommes (HSH). Elle s'inscrit dans le dispositif de surveillance du VIH, établi par l'Office fédéral de la santé publique, en tant qu'instrument de suivi des comportements face au VIH/Sida dans ce groupe-cible. Elle a déjà été réalisée à dix reprises. L'enquête Gaysurvey 2014 était disponible en ligne sur Internet et consistait en un questionnaire anonyme auto-administré. Le nombre de participant est de 834 personnes. Pour sa onzième édition, Gaysurvey reste un instrument pertinent du suivi des comportements des HSH face au VIH/Sida. Certaines tendances observées ces dernières années ont été confirmées, de nouveaux thèmes ont été abordés et de nouveaux éléments de réflexions apportés

Cold Atom Clock Test of Lorentz Invariance in the Matter Sector

We report on a new experiment that tests for a violation of Lorentz invariance (LI), by searching for a dependence of atomic transition frequencies on the orientation of the spin of the involved states (Hughes-Drever type experiment). The atomic frequencies are measured using a laser cooled $^{133}$Cs atomic fountain clock, operating on a particular combination of Zeeman substates. We analyze the results within the framework of the Lorentz violating standard model extension (SME), where our experiment is sensitive to a largely unexplored region of the SME parameter space, corresponding to first measurements of four proton parameters and improvements by 11 and 13 orders of magnitude on the determination of four others. In spite of the attained uncertainties, and of having extended the search into a new region of the SME, we still find no indication of LI violation.Comment: 4 pages, accepted for Physical Review Letter

Effects of Common Origin and Common Rearing Environment on Variance in Ectoparasite Load and Phenotype of Nestling Alpine Swifts

Knowledge of the quantitative genetics of resistance to parasitism is key to appraise host evolutionary responses to parasite selection. Here, we studied effects of common origin (i.e. genetic and pre-hatching parental effects) and common rearing environment (i.e. post-hatching parental effects and other environment effects) on variance in ectoparasite load in nestling Alpine swifts (Apusmelba). This colonial bird is intensely parasitized by blood sucking louse-flies that impair nestling development and survival. By cross-fostering half of the hatchlings between pairs of nests, we show strong significant effect of common rearing environment on variance (90.7% in 2002 and 90.9% in 2003) in the number of louse-flies per nestling and no significant effect of common origin on variance in the number of louse-flies per nestling. In contrast, significant effects of common origin were found for all the nestling morphological traits (i.e. body mass, wing length, tail length, fork length and sternum length) under investigation. Hence, our study suggests that genetic and pre-hatching parental effects play little role in the distribution of parasites among nestling Alpine swifts, and thus that nestlings have only limited scope for evolutionary responses against parasites. Our results highlight the need to take into consideration environmental factors, including the evolution of post-hatching parental effects such as nest sanitation, in our understanding of host-parasite relationship

Guide d'introduction à l'évaluation d'impact sur la santé en Suisse

Ce guide traite de l’Evaluation d’Impact sur la Santé (EIS) et des étapes du processus EIS. L’EIS est un outil novateur d’aide à la décision qui vise à évaluer les effets potentiels, positifs et négatifs sur la santé des politiques publiques, au travers de recommandations pour en maximiser les impacts positifs et atténuer les impacts négatifs. C’est le premier document qui décrit en détail le processus EIS en Suisse. Il se différencie des autres guides EIS existants dans la littérature internationale en ce sens qu’il découle directement des expériences réalisées par les Cantons (Genève, Jura et Tessin), cantons pionniers dans le domaine de l’EIS en Suisse