937 research outputs found
Physics potential of the CERN-MEMPHYS neutrino oscillation project
We consider the physics potential of CERN based neutrino oscillation
experiments consisting of a Beta Beam (BB) and a Super Beam (SPL) sending
neutrinos to MEMPHYS, a 440 kt water \v{C}erenkov detector at Frejus, at a
distance of 130 km from CERN. The discovery reach and the
sensitivity to CP violation are investigated, including a detailed discussion
of parameter degeneracies and systematical errors. For SPL sensitivities
similar to the ones of the phase II of the T2K experiment (T2HK) are obtained,
whereas the BB may reach significantly better sensitivities, depending on the
achieved number of total ion decays. The results for the CERN-MEMPHYS
experiments are less affected by systematical uncertainties than T2HK. We point
out that by a combination of data from BB and SPL a measurement with
antineutrinos is not necessary and hence the same physics results can be
obtained within about half of the measurement time compared to one single
experiment. Furthermore, it is shown how including data from atmospheric
neutrinos in the MEMPHYS detector allows to resolve parameter degeneracies and,
in particular, provides sensitivity to the neutrino mass hierarchy and the
octant of .Comment: 32 pages, 17 figures, minor improvements on the text wrt to v2,
version to appear in JHE
PARISROC, a Photomultiplier Array Integrated Read Out Chip
PARISROC is a complete read out chip, in AMS SiGe 0.35 !m technology, for
photomultipliers array. It allows triggerless acquisition for next generation
neutrino experiments and it belongs to an R&D program funded by the French
national agency for research (ANR) called PMm2: ?Innovative electronics for
photodetectors array used in High Energy Physics and Astroparticles?
(ref.ANR-06-BLAN-0186). The ASIC (Application Specific Integrated Circuit)
integrates 16 independent and auto triggered channels with variable gain and
provides charge and time measurement by a Wilkinson ADC (Analog to Digital
Converter) and a 24-bit Counter. The charge measurement should be performed
from 1 up to 300 photo- electrons (p.e.) with a good linearity. The time
measurement allowed to a coarse time with a 24-bit counter at 10 MHz and a fine
time on a 100ns ramp to achieve a resolution of 1 ns. The ASIC sends out only
the relevant data through network cables to the central data storage. This
paper describes the front-end electronics ASIC called PARISROC.Comment: IEEE Nuclear Science Symposium an Medical Imaging Conference (2009
NSS/MIC
MEMPHYS:A large scale water Cerenkov detector at Fr\'ejus
A water \v{C}erenkov detector project, of megaton scale, to be installed in
the Fr\'ejus underground site and dedicated to nucleon decay, neutrinos from
supernovae, solar and atmospheric neutrinos, as well as neutrinos from a
super-beam and/or a beta-beam coming from CERN, is presented and compared with
competitor projects in Japan and in the USA. The performances of the European
project are discussed, including the possibility to measure the mixing angle
and the CP-violating phase .Comment: 1+33 pages, 14 figures, Expression of Interest of MEMPHYS projec
Acyl-Imidazoles A Privileged Ester Surrogate for Enantioselective Synthesis
International audienceSince the first report by Evans in asymmetric FriedelâCrafts reactions, the use of acylâimidazoles has blossomed as powerful ester/amide surrogates. The imidazole scaffold indeed displays stability and special activation features allowing both better reactivity and selectivity in traditional ester/amide functionalizations: αâ(enolate chemistry), ÎČâ(conjugate additions), α,ÎČâ(cycloadditions) or Îł/ÎŽâ(vinylogous). An overview of the contemporary and growing interest in acylâimidazoles in metalâ and organoâcatalyzed transformations (bioâhybrid catalytic systems will be fully described in a backâtoâback Minireview) will be highlighted. Moreover, postâfunctionalization expediencies are also going to be discussed in this Minireview
BAORadio : Cartographie 3D de la distribution de gaz H dans l'Univers
3D mapping of matter distribution in the universe through the 21 cm radio
emission of atomic hydrogen is a complementary approach to optical surveys for
the study of the Large Scale Structures, in particular for measuring the BAO
(Baryon Acoustic Oscillation) scale up to redshifts z <~ 3 and constrain dark
energy. We propose to carry such a survey through a novel method, called
intensity mapping, without detecting individual galaxies radio emission. This
method requires a wide band instrument, 100 MHz or larger, and multiple beams,
while a rather modest angular resolution of 10 arcmin would be sufficient. The
instrument would have a few thousand square meters of collecting area and few
hundreds of simultaneous beams. These constraints could be fulfilled with a
dense array of receivers in interferometric mode, or a phased array at the
focal plane of a large antenna
DNA-Based Asymmetric Inverse Electron-Demand Hetero-Diels-Alder
International audienceWhile artificial cyclases hold great promise in chemical synthesis, this work presents the first example of a DNA-catalyzed inverse electron-demand hetero-Diels-Alder (IEDHDA) between dihydrofuran and various α,ÎČ-unsaturated acyl imidazoles. The resulting fused bicyclic O,O-acetals containing three contiguous stereogenic centers are obtained in high yields (up to 99â%) and excellent diastereo- (up to >99:1 dr) and enantioselectivities (up to 95â% ee) using a low catalyst loading. Most importantly, these results show that the concept of DNA-based asymmetric catalysis can be expanded to new synthetic transformations offering an efficient, sustainable, and highly selective tool for the construction of chiral building blocks
GPCR-OKB: the G protein coupled receptor oligomer knowledge base
Rapid expansion of available data about G Protein Coupled Receptor (GPCR) dimers/oligomers over the past few years requires an effective system to organize this information electronically. Based on an ontology derived from a community dialog involving colleagues using experimental and computational methodologies, we developed the GPCR-Oligomerization Knowledge Base (GPCR-OKB). GPCR-OKB is a system that supports browsing and searching for GPCR oligomer data. Such data were manually derived from the literature. While focused on GPCR oligomers, GPCR-OKB is seamlessly connected to GPCRDB, facilitating the correlation of information about GPCR protomers and oligomers
- âŠ