1,048 research outputs found
First Characterization of the Ultra-Shielded Chamber in the Low-noise Underground Laboratory (LSBB) of Rustrel Pays d'Apt
In compliance with international agreements on nuclear weapons limitation,
the French ground-based nuclear arsenal has been decommissioned in its
totality. One of its former underground missile control centers, located in
Rustrel, 60 km east of Avignon (Provence) has been converted into the
``Laboratoire Souterrain \`a Bas Bruit de Rustrel-Pays d'Apt'' (LSBB). The
deepest experimental hall (500 m of calcite rock overburden) includes a 100
m area of sturdy flooring suspended by and resting on shock absorbers,
entirely enclosed in a 28 m-long, 8 m-diameter, 1 cm-thick steel Faraday cage.
This results in an unparalleled combination of shielding against cosmic rays,
acoustic, seismic and electromagnetic noise, which can be exploited for rare
event searches using ultra low-temperature and superconducting detectors. The
first characterization measurements in this unique civilian site are reported.
For more info see http://home.cern.ch/collar/RUSTREL/rustrel.htmlComment: Homepage and quoted hyperlinks have been updated: see
http://home.cern.ch/collar/RUSTREL/rustrel.htm
Prospects For Identifying Dark Matter With CoGeNT
It has previously been shown that the excess of events reported by the CoGeNT
collaboration could be generated by elastically scattering dark matter
particles with a mass of approximately 5-15 GeV. This mass range is very
similar to that required to generate the annual modulation observed by
DAMA/LIBRA and the gamma rays from the region surrounding the Galactic Center
identified within the data of the Fermi Gamma Ray Space Telescope. To
confidently conclude that CoGeNT's excess is the result of dark matter,
however, further data will likely be needed. In this paper, we make projections
for the first full year of CoGeNT data, and for its planned upgrade. Not only
will this body of data more accurately constrain the spectrum of nuclear recoil
events, and corresponding dark matter parameter space, but will also make it
possible to identify seasonal variations in the rate. In particular, if the
CoGeNT excess is the product of dark matter, then one year of CoGeNT data will
likely reveal an annual modulation with a significance of 2-3. The
planned CoGeNT upgrade will not only detect such an annual modulation with high
significance, but will be capable of measuring the energy spectrum of the
modulation amplitude. These measurements will be essential to irrefutably
confirming a dark matter origin of these events.Comment: 6 pages, 6 figure
Results of an initial trial of a satellite telemetering buoy measuring near surface current
The kinetic dark-mixing in the light of CoGENT and XENON100
Several string or GUT constructions motivate the existence of a dark U(1)_D
gauge boson which interacts with the Standard Model only through its kinetic
mixing. We compute the dark matter abundance in such scenario and the
constraints in the light of the recent data from CoGENT, CDMSII and XENON100.
We show in particular that a region with relatively light WIMPS, M_{Z_D}< 40
GeV and a kinetic mixing 10^-4 < delta < 10^-3 is not yet excluded by the last
experimental data and seems to give promising signals in a near future. We also
compute the value of the kinetic mixing needed to explain the
DAMA/CoGENT/CRESST excesses and find that for M_{Z_D}< 30 GeV, delta ~ 10^-3 is
sufficient to fit with the data.Comment: 6 pages, 5figure
Aktivität und Vorkommen geflügelter Blattläuse auf Freilandpaprika in Spanien
Horizontal mosaic-green-tile traps were placed in various pepper-growing areas of Spain: Aranjuez and
Arganda del Rey (Madrid), Balboa (Badajoz), Cadreita (Pamplona), Mendavia and Sartaguda (Logroño),
Montañana (Zaragoza), Pueblo Nuevo (Valencia) and Torrepacheco (Murcia). These mosaic-greentraps
resembled much better the pepper canopy than the commonly used yellow water traps, as
indicated by absorbance spectrophotometry. Sampling was extended throughout the pepper crop cycle
during 1990, 1991 and 1992. Over that time, 14,363 aphids, belonging to 99 species/taxa were
captured. Aphis was the principal genus captured:
57.5 % of the total (17 % belonging to the species Aphis fabae (Scopoli)). Other abundant species
were: Myzus (Nectarosiphon) persicae (Sulzer) (7.46 %), Diuraphis noxia (Mordvilko) (5.23 %), Brachycaudus
spp. (3.73 %), Sitobion avenae (F.) (2.51 %), Macrosiphum euphorbiae (Thomas) (2.46 %),
Rhopalosiphum spp. (2.20 %) and Therioaphis spp. (1.99 %). The species included in the genus Aphis
were the most abundant in all the regions sampled, although M. (N.) persicae was also predominant in
the Zaragoza and Pamplona region, and D. noxia was frequently found in the Madrid region. A first
aphid peak was observed soon after transplanting (May–June) in most of the regions and years sampled.Horizontale mosaikgrüne Farbfallen wurden in verschiedenen Paprika-Anbaugebieten in Spanien
aufgestellt: Aranjuez und Arganda del Rey (Madrid), Balbao (Badajoz), Cadreita (Pamplona), Mendavia
und Sartaguda (Logroño), Montañana (Zaragoza), Pueblo Nuevo (Valencia) und Torrepacheco
(Murcia). Diese mosaikgrünen Fallen ähnelten sehr viel besser den Farben des Paprikabestandes als
die üblicherweise eingesetzten gelben Wasserfallen wie durch Absorptionsspektrometrie festgestellt
wurde. Die Probennahmen erfolgten während der ganzen Wachstumsphasen des Paprikas in den
Jahren 1990, 1991 und 1992. In diesen Zeiträumen konnten 14363 Blattläuse gefangen werden, die
99 Arten/Taxa angehörten. Die Gattung Aphis wurde mit 57,5 % am häufigsten gefangen, 17 %
gehörten zur Art Aphis fabae (Scopoli). Andere häufig vorkommende Arten waren: Myzus (Nectarosiphon)
persicae (Sulzer) (7,46 %), Diuraphis noxia (Mordvilko) (5,23 %), Brachycaudus spp. (3,73 %),
Sitobion avenae (F.) (2,51 %), Macrosiphum euphorbiae (Thomas) (2,46 %), Rhopalosiphum spp.
(2,20 %) und Therioaphis spp. (1,99 %). Die zur Gattung Aphis gehörenden Arten waren in allen
beprobten Regionen am häufigsten, obgleich M. (N.) persicae in den Regionen Zaragoza und Pamplona
auch sehr häufig vorkam. D. noxia trat häufig in der Madrider Region auf. Ein erster Höhehoug punkt des Blattlausaufretens wurde in den meisten Regionen und Jahren schon bald nach dem
Auspflanzen (Mai–Juni) beobachtet.This
work was supported by the Interministerial Commision for Science and Technology of Spain (Comisión
Interministerial de Ciencia y Tecnología, grant AGR91-0448)..Peer reviewe
Superheated Microdrops as Cold Dark Matter Detectors
It is shown that under realistic background considerations, an improvement in
Cold Dark Matter sensitivity of several orders of magnitude is expected from a
detector based on superheated liquid droplets. Such devices are totally
insensitive to minimum ionizing radiation while responsive to nuclear recoils
of energies ~ few keV. They operate on the same principle as the bubble
chamber, but offer unattended, continuous, and safe operation at room
temperature and atmospheric pressure.Comment: 15 pgs, 4 figures include
The smallest eigenvalue of Hankel matrices
Let H_N=(s_{n+m}),n,m\le N denote the Hankel matrix of moments of a positive
measure with moments of any order. We study the large N behaviour of the
smallest eigenvalue lambda_N of H_N. It is proved that lambda_N has exponential
decay to zero for any measure with compact support. For general determinate
moment problems the decay to 0 of lambda_N can be arbitrarily slow or
arbitrarily fast. In the indeterminate case, where lambda_N is known to be
bounded below by a positive constant, we prove that the limit of the n'th
smallest eigenvalue of H_N for N tending to infinity tends rapidly to infinity
with n. The special case of the Stieltjes-Wigert polynomials is discussed
Estudo piloto sobre resposta de curto prazo corneal à terapia corneal refractiva da miopia de efeitos refractivos distintos
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