1,526 research outputs found
What do we really know about Dark Energy?
In this paper I discuss what we truly know about dark energy. I shall argue
that up to date our single indication for the existence of dark energy comes
from distance measurements and their relation to redshift. Supernovae, CMB
anisotropies and observations of baryon acoustic oscillations, they all simply
tell us that the observed distance to a given redshift is larger than the one
expected from a Friedmann Lemaitre universe with matter only and the locally
measured Hubble parameter.Comment: invited talk at the meeting "Cosmological Tests of General
Relativity" at the Kavli Royal Society Center for the Advancement of Science
organized by Rachel Bean, Pedro Ferreira and Andy Taylor. 14p 2 figs. revised
version: updated to match version in print in Phil. Trans. R. Soc.
Directional Detection of Dark Matter with MIMAC
Directional detection is a promising search strategy to discover galactic
Dark Matter. We present a Bayesian analysis framework dedicated to Dark Matter
phenomenology using directional detection. The interest of directional
detection as a powerful tool to set exclusion limits, to authentify a Dark
Matter detection or to constrain the Dark Matter properties, both from particle
physics and galactic halo physics, will be demonstrated. However, such results
need highly accurate track reconstruction which should be reachable by the
MIMAC detector using a dedicated readout combined with a likelihood analysis of
recoiling nuclei.Comment: 4 pages, 2 figures, to appear in the proceedings of the TAUP 2011
conference held in Munich (5 - 9 September, 2011
Background Rejection in the DMTPC Dark Matter Search Using Charge Signals
The Dark Matter Time Projection Chamber (DMTPC) collaboration is developing
low-pressure gas TPC detectors for measuring WIMP-nucleon interactions. Optical
readout with CCD cameras allows for the detection for the daily modulation in
the direction of the dark matter wind, while several charge readout channels
allow for the measurement of additional recoil properties. In this article, we
show that the addition of the charge readout analysis to the CCD allows us too
obtain a statistics-limited 90% C.L. upper limit on the rejection factor
of for recoils with energies between 40 and 200
keV. In addition, requiring coincidence between charge signals
and light in the CCD reduces CCD-specific backgrounds by more than two orders
of magnitude.Comment: 8 pages, 6 figures. For proceedings of DPF 2011 conferenc
Biology and control of reproduction of sturgeons in fish farm
Over the last century the reproduction of sturgeon has been intensively studied par Russian scientists who established a technology for the ranching of alevins which included artificial fertilization of gametes taken from wild broodfish and larvae rearing. More recently, since 1970, major contributions originated from teams in the USA, the EU, Japan and Iran. A rather good knowledge of the reproductive physiology of sturgeon is now available: gametogenesis, reproductive cycle, ovulation, spermiation and fertilization. The complete life cycle was obtained in captive conditions allowing the production of juveniles and caviar
Directional detection of Dark Matter with MIMAC: WIMP identification and track reconstruction
Directional detection is a promising Dark Matter search strategy. Indeed,
WIMP-induced recoils present a direction dependence toward the Cygnus
constellation, while background-induced recoils exhibit an isotropic
distribution in the galactic rest frame. Taking advantage on these
characteristic features and even in the presence of a sizeable background, we
show for the first time the possibility to constrain the WIMP properties, both
from particle and galactic halo physics, leading to an identification of
non-baryonic Dark Matter. However, such results need highly accurate track
reconstruction which should be reachable by the MIMAC detector using a
dedicated readout combined with a likelihood analysis of recoiling nuclei.Comment: 8 pages, 5 figures, 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
On the Debye temperature in the Slack approximation for an estimation of the thermal conductivity of nonmetallic compounds
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