University Of Neuchgtel

La Chaux-de-Fonds, Switzerland

University Of Neuchgtel

La Chaux-de-Fonds, Switzerland
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Bouattour A.,Institute Pasteur Of Tunis | Garnier M.,Institute Pasteur Paris | M'Ghirbi Y.,Institute Pasteur Of Tunis | Sarih M.,Institute Pasteur Of Casablanca | And 5 more authors.
Vector-Borne and Zoonotic Diseases | Year: 2010

Tick-borne relapsing fever (TBRF) is caused by Borrelia species transmitted to humans by infected Ornithodoros sp. ticks. The disease has been rarely described in North Africa, and in Tunisia the local transmission of TBRF seems to have disappeared or is undiagnosed. A longitudinal study was conducted in 14 sites located in four different bioclimatic zones of Tunisia to assess both the distribution of Ornithodoros sp. and their infection rate with the relapsing fever Borrelia sp. Three polymerase chain reaction methods targeting the 16S rRNA, the intergenic spacer, and the fla (flagellin) genes were used and phylogenetic analyses were carried out. Three hundred and fifty-eight specimens of Ornithodoros were collected: O. erraticus (previously termed "small variety") (n=190) and O. normandi (n=168). Borrelia crocidurae DNA was detected in 15.1% of O. erraticus (small variety) (24 out of the 159 randomly selected for testing) collected in rodent burrows situated in the arid and Saharan areas in southern Tunisia. Molecular analysis targeting the 16S rRNA gene and the noncoding intergenic spacer domain showed good resolution for this Borrelia sp., although no molecular polymorphism was evidenced according to location. In contrast, none of the 133 O. normandi, also randomly selected for testing, was infected by Borrelia sp. and these ticks were restricted to the subhumid and semiarid zones in northern Tunisia. Both O. erraticus (small variety) and O. normandi were found in Tunisia and the high B. crocidurae infection rate found in O. erraticus highlights the risk of TBRF transmission in the southern part of the country. © Copyright 2010, Mary Ann Liebert, Inc.

Breschi E.,University of Neuchgtel | Kazakov G.,Saint Petersburg State Polytechnic University | Schori C.,University of Neuchgtel | Di Domenico G.,University of Neuchgtel | And 3 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We report on light shift and broadening in the atomic-motion-induced Ramsey narrowing of dark resonances prepared in alkali-metal vapors contained in wall-coated cells without buffer gas. The atomic-motion-induced Ramsey narrowing is due to the free motion of the polarized atomic spins in and out of the optical interaction region before spin relaxation. As a consequence of this effect, we observe a narrowing of the dark resonance linewidth as well as a reduction of the ground states' light shift when the volume of the interaction region decreases at constant optical intensity. The results can be intuitively interpreted as a dilution of the intensity effect similar to a pulsed interrogation due to the atomic motion. Finally the influence of this effect on the performance of compact atomic clocks is discussed. © 2010 The American Physical Society.

Di Domenico G.,University Of Neuchgtel | Devenoges L.,University Of Neuchgtel | Stefanov A.,Swiss Federal Office of Metrology | Joyet A.,University Of Neuchgtel | Thomann P.,University Of Neuchgtel
EPJ Applied Physics | Year: 2011

Ramsey fringes observed in an atomic fountain are formed by the superposition of the individual atomic signals. Due to the atomic beam residual temperature, the atoms have slightly different trajectories and thus are exposed to a different average magnetic field, and a velocity-dependent Ramsey interaction time. As a consequence, both the velocity distribution and magnetic field profile are imprinted in the Ramsey fringes observed on Zeeman sensitive microwave transitions. In this work, we perform a Fourier analysis of the measured Ramsey signals to retrieve both the time-averaged magnetic field associated with different trajectories and the velocity distribution of the atomic beam. We use this information to reconstruct Ramsey fringes and establish an analytical expression for the value of the microwave frequency for which individual Ramsey fringes add most constructively and are thus visible in the microwave spectrum. © EDP Sciences, 2011.

Gonzalez-Pacanowski T.,International University of Catalonia | Medina-Aguerrebere P.,University Of Neuchgtel
Profesional de la Informacion | Year: 2011

Patients are turning increasingly to blogs to learn about health and to share experiences related to this area. These blogs are written by patients or health professionals and constitute an exceptional aid for the promotion of education in health issues for this population. The high educational level of the bloggers, the variety of sources of information used and the different aims pursued make these blogs full participants in the health area. The article concludes that the blog is a new meeting point between doctor and patient that has a positive impact on the improvement of the health service offered by hospitals.

Burri C.,University of Neuchgtel | Dupasquier C.,University of Neuchgtel | Bastic V.,University of Neuchgtel | Gern L.,University of Neuchgtel
Vector-Borne and Zoonotic Diseases | Year: 2011

This study is part of a project that aimed to better understand the role of small mammals in the maintenance of the tick-borne encephalitis virus at four different sites in Switzerland. Here we focused on the detection of three intracellular pathogens, Anaplasma phagocytophilum, Rickettsia spp., and Babesia spp., in field-derived ticks that detached from 79 small mammals. We analyzed 465 Ixodes ricinus larvae after their molt and 14 semiengorged I. trianguliceps that were feeding on rodents. No pathogen was detected in I. trianguliceps. In I. ricinus, the most frequently detected pathogen was Rickettsia spp. (7.3%). All Rickettsia spp. identified DNA belonged to R. helvetica except one DNA sample that was identified as R. monacensis. The prevalence of Babesia spp. reached 2.4% and identification at the species level revealed B. venatorum (1.7%) and B. microti (0.4%). A. phagocytophilum was not detected in I. ricinus that detached from rodents. To verify the absence of A. phagocytophilum at the four sites, additional questing nymphs collected at these sites were analyzed for A. phagocytophilum. This pathogen was detected at one site only, where 2% (2/100) of questing ticks were infected. Some of these emerging pathogens are described for the first time in molted larvae that fed on rodents. The presence of medically relevant pathogens, with a global prevalence of 9.9%, highlights the importance to inform the medical corporation on the risk for human health in these areas. © 2011, Mary Ann Liebert, Inc.

Perret C.,Électricité de France | Hauet A.,Électricité de France | Parrel D.,Électricité de France | Saysset G.,Électricité de France | And 2 more authors.
Houille Blanche | Year: 2012

EDF runs a complete hydrometeorological measurement network focused on French mountainous regions. Rain, snow water equivalent and stream flows are monitored in order to forecast inflows in hydroloeletric reservoirs. Indeed, half of the gauging stations and 60 % of the rain gauges of this network are located at an altitude higher than 600 m. This paper presents an overview of this network, how it has been specifically adapted to its mountainous environment, and details the last methodological enhancements of the stream flow measurement by dilution of a fluorescent dye. The dilution technique is advantageous to face operating difficulties in torrential flow conditions. © 2012 Société Hydrotechnique de France.

Di Domenico G.,University Of Neuchgtel | Devenoges L.,University Of Neuchgtel | Dumas C.,University Of Neuchgtel | Thomann P.,University Of Neuchgtel
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We use two-laser optical pumping on a continuous atomic fountain in order to prepare cold cesium atoms in the same quantum ground state. A first laser excites the F=4 ground state to pump the atoms toward F=3 while a second π-polarized laser excites the F=3→F⊃'=3 transition of the D 2 line to produce Zeeman pumping toward m=0. To avoid trap states, we implement the first laser in a two-dimensional optical lattice geometry, thereby creating polarization gradients. This configuration has the advantage of simultaneously producing Sisyphus cooling when the optical lattice laser is tuned between the F=4→F⊃'=4 and F=4→F⊃'=5 transitions of the D2 line, which is important to remove the heat produced by optical pumping. Detuning the frequency of the second π-polarized laser reveals the action of a mechanism improving both laser cooling and state-preparation efficiency. A physical interpretation of this mechanism is discussed. © 2010 The American Physical Society.

Gold S.,University of Neuchgtel
Journal on Chain and Network Science | Year: 2012

As stocks of fossil fuels become harder to access and exploit worldwide, renewable energies as a sustainable option have entered the limelight in recent years. Bio-energy plays an essential role in the current mix of renewable energy technologies. In Germany, the state fosters insistently biogas technology within the concert of bio-energy options. Literature suggests that long-term stable economic ties with supplying farmers are the pivotal managerial challenge of bio-energy plant operators to secure a constant and competitively priced feedstock supply. Biogas plant operators are generally in a vulnerable position vis-à-vis their suppliers due to their substantial specific capital investment and a rather restricted economically viable catchment area. Transactional uncertainty due to volatile agricultural market prices, changing yield quantities, and unpredictable behaviour of suppliers makes biogas plant operators aim for effective governance. The study aims by means of in-depth interviews to explore how biogas plant operators perceive their specific situation of transactional uncertainty and which instruments (concerning formal and relational contracts) they use for securing stable and constant feedstock supply. Findings indicate that mutually reinforcing interaction of formal contracts, business partnerships, and equity participation with relational contracts proves to be successful in establishing long-term stable feedstock supply. While the specific rural societal culture has an ambiguous impact on governance design, local rootedness of biogas plant operators provide high levels of social capital and thus clearly facilitate the search for effective solutions that satisfy all parties.

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