110 research outputs found
Sexualité et procréation chez les Mvae (Cameroun)
Chez les Mvae du Sud-Cameroun (groupe Beti Fang), l'étiologie de la maladie associée à la stérilité permet de penser le corps féminin dans ses rapports au corps masculin et d'établir le lien entre le corps social et l'univers. Dans le premier cas, les interdits sexuels, provisoires ou permanents, établissent les cadres culturels de la sexualité socialement proscrite, dans un régime de relative liberté sexuelle ; en cas de rupture d'interdit, l'origine de la maladie est attribuée au comportement de la femme, et renvoie à une théorie des liquides corporels et de leurs contacts. Dans le deuxième cas, l'origine de la maladie est attribuée à une action maléfique extérieure au corps de la femme et intérieure au corps social. Ces deux niveaux d'interprétation forment un continuum, dont l'étude nous amène au plus profond de la société mvae. (Résumé d'auteur
Trigger and readout electronics for the STEREO experiment
The STEREO experiment will search for a sterile neutrino by measuring the
anti-neutrino energy spectrum as a function of the distance from the source,
the ILL nuclear reactor. A dedicated electronic system, hosted in a single
microTCA crate, was designed for this experiment. It performs triggering in two
stages with various selectable conditions, processing and readout via UDP/IPBUS
of 68 photomultiplier signals continuously digitized at 250 MSPS. Additionally,
for detector performance monitoring, the electronics allow on-line calibration
by driving LED synchronously with the data acquisition. This paper describes
the electronics requirements, architecture and the performances achieved.Comment: Topical Workshop on Electronics for Particle Physics (TWEPP) 2015,
Lisboa. 9 pages, 9 figure
NIKEL: Electronics and data acquisition for kilopixels kinetic inductance camera
A prototype of digital frequency multiplexing electronics allowing the real
time monitoring of microwave kinetic inductance detector (MKIDs) arrays for
mm-wave astronomy has been developed. Thanks to the frequency multiplexing, it
can monitor simultaneously 400 pixels over a 500 MHz bandwidth and requires
only two coaxial cables for instrumenting such a large array. The chosen
solution and the performances achieved are presented in this paper.Comment: 21 pages, 14 figure
MIMAC : A micro-tpc matrix for directional detection of dark matter
Directional detection of non-baryonic Dark Matter is a promising search
strategy for discriminating WIMP events from background. However, this strategy
requires both a precise measurement of the energy down to a few keV and 3D
reconstruction of tracks down to a few mm. To achieve this goal, the MIMAC
project has been developed. It is based on a gaseous micro-TPC matrix, filled
with CF4 and CHF3. The first results on low energy nuclear recoils (H, F)
obtained with a low mono-energetic neutron field are presented. The discovery
potential of this search strategy is discussed and illustrated by a realistic
case accessible to MIMAC.Comment: 6 pages, Proc. of the fifth international symposium on large TPCs for
low energy rare event detection, Paris, France, Dec. 2010. To appear in
Journal of Physic
Design and construction of a Cherenkov imager for charge measurement of nuclear cosmic rays
A proximity focusing Cherenkov imager called CHERCAM, has been built for the
charge measurement of nuclear cosmic rays with the CREAM instrument. It
consists of a silica aerogel radiator plane across from a detector plane
equipped with 1,600 1" diameter photomultipliers. The two planes are separated
by a ring expansion gap. The Cherenkov light yield is proportional to the
charge squared of the incident particle. The expected relative light collection
accuracy is in the few percents range. It leads to an expected single element
separation over the range of nuclear charge Z of main interest 1 < Z < 26.
CHERCAM is designed to fly with the CREAM balloon experiment. The design of the
instrument and the implemented technical solutions allowing its safe operation
in high altitude conditions (radiations, low pressure, cold) are presented.Comment: 24 pages, 19 figure
Tests at 2K of the beta 0.35 spoke cryomodule prototype with the MTCA.4-based Low Level RF system prototype for the MYRRHA R&D
Within the framework of the first phase of MYRRHA (Multi-purpose hYbrid
Research Reactor for High-tech Applications) project, called MINERVA, IJCLab
was in charge of a fully equipped Spoke cryomodule prototype development,
tested at 2K. It integrates two superconducting single spoke cavities, the RF
power couplers and the Cold Tuning Systems associated. On the control side, a
MTCA.4-based Low Level Radio Frequency (LLRF) system prototype and the
Software/EPICS developments has been realized by IJCLab and the SCK CEN in
collaboration with the company IOxOS Technologies. The final version of the
global system and the results of the tests at 2K will show with some
perspectives.Comment: Poster pr\'esent\'e au LLRF Workshop 2023 (LLRF2023, arXiv :
2310.03199
High Current, High frequency ECRIS development program for LHC heavy ion beam application
A research program with the aim of producing pulsed currents with hitherto unequalled intensity of Pb27+, with length and repetition ratecompatible with those desired by CERN (1 mAe / 400 ms / 10 Hz in the context of future heavy ion collisions at LHC) is organised in acollaboration between CERN/GSI/CEA-Grenoble and IN2P3-ISNG.Two main experimental programs will be carried out : (i) tests with the LNS-Catania team on the SERSE superconducting source with a 28 GHzgyrotron, (ii) tests on a non-superconducting source (new source at Grenoble) with a 28 GHz gyrotron. For this purpose CEA/DRFMC hasborrowed from CEA a 28 GHz - 10 kW gyrotron transmitter.The project includes also the construction of a source body, by ISNG, with conventional coils and permanent magnets for working at the frequencyof about 28 GHz and biased up to 60 kV. This source called PHOENIX will run on a test bench at ISN. PHOENIX is an improvement of thepresent ECR4-14.5 GHz/CERN source, having a mirror ratio R=2 at 14.5 GHz, and R=1.7 at 28 GHz (possibly reaching 2.1 T on the axis of thesource), and with a plasma volume up to 2.5 larger.Experiments at 28 GHz will be performed on the SERSE source in Catania at INFN/LNS where both the axial and the hexapolar fields will bevaried so that the mirror ratio is continuously varied up to R=1.6 ; the SERSE source will be also operated at lower magnetic fields such as thosewhich can be produced by conventional magnets (less than 2 T axial field at injection - far from the 28 GHz High-B mode)
Lichenological exploration of Algeria: historical overview and annotated bibliography, 1799-2013
yesDespite more than two centuries of almost uninterrupted surveys and studies of Algerian lichenology, the history and lichen diversity of Algeria are still poorly understood. During the preparation of a forthcoming checklist of Algerian lichens it was considered necessary to provide the present historical overview of lichenological exploration of the country from 1799 to 2013, supported by a reasonably comprehensive annotated bibliography of 171 titles
Chemical Magnetoreception: Bird Cryptochrome 1a Is Excited by Blue Light and Forms Long-Lived Radical-Pairs
Cryptochromes (Cry) have been suggested to form the basis of light-dependent magnetic compass orientation in birds. However, to function as magnetic compass sensors, the cryptochromes of migratory birds must possess a number of key biophysical characteristics. Most importantly, absorption of blue light must produce radical pairs with lifetimes longer than about a microsecond. Cryptochrome 1a (gwCry1a) and the photolyase-homology-region of Cry1 (gwCry1-PHR) from the migratory garden warbler were recombinantly expressed and purified from a baculovirus/Sf9 cell expression system. Transient absorption measurements show that these flavoproteins are indeed excited by light in the blue spectral range leading to the formation of radicals with millisecond lifetimes. These biophysical characteristics suggest that gwCry1a is ideally suited as a primary light-mediated, radical-pair-based magnetic compass receptor
Human Cryptochrome-1 Confers Light Independent Biological Activity in Transgenic Drosophila Correlated with Flavin Radical Stability
Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome - 1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism
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