The CDMS and EDELWEISS collaborations have combined the results of their direct searches for dark matter using cryogenic germanium detectors. The total data set represents 614 kg.d equivalent ...exposure. A straightforward method of combination was chosen for its simplicity before data were exchanged between experiments. The results are interpreted in terms of limits on spin-independent WIMP-nucleon cross-section. For a WIMP mass of 90 GeV/c^2, where this analysis is most sensitive, a cross-section of 3.3 x 10^{-44} cm^2 is excluded at 90% CL. At higher WIMP masses, the combination improves the individual limits, by a factor 1.6 above 700 GeV/c^2. Alternative methods of combining the data provide stronger constraints for some ranges of WIMP masses and weaker constraints for others.
Muon-induced neutrons constitute a prominent background component in a number of low count rate experiments, namely direct searches for Dark Matter. In this work we describe a neutron detector to ...measure this background in an underground laboratory, the Laboratoire Souterrain de Modane. The system is based on 1 m3 of Gd-loaded scintillator and it is linked with the muon veto of the EDELWEISS-II experiment for coincident muon detection. The system was installed in autumn 2008 and passed since then a number of commissioning tests proving its full functionality. The data-taking is continuously ongoing and a count rate of the order of 1 muon-induced neutron per day has been achieved.
This paper describes precise measurements of the thermal neutron flux in the LSM underground laboratory in proximity of the EDELWEISS-II dark matter search experiment together with short measurements ...at various other locations. Monitoring of the flux of thermal neutrons is accomplished using a mobile detection system with low background proportional counter filled with \(^3\)He. On average 75 neutrons per day are detected with a background level below 1 count per day (cpd). This provides a unique possibility of a day by day study of variations of the neutron field in a deep underground site. The measured average 4\(\pi\) neutron flux per cm\(^{2}\) in the proximity of EDELWEISS-II is \(\Phi_{MB}=3.57\pm0.05^{stat}\pm0.27^{syst}\times 10^{-6}\) neutrons/sec. We report the first experimental observation that the point-to-point thermal neutron flux at LSM varies by more than a factor two.
The EDELWEISS-II collaboration has performed a direct search for WIMP dark matter with an array of ten 400 g heat-and-ionization cryogenic detectors equipped with interleaved electrodes for the ...rejection of near-surface events. Six months of continuous operation at the Laboratoire Souterrain de Modane have been achieved. The observation of one nuclear recoil candidate above 20 keV in an effective exposure of 144 kgd is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 1.0x10^-7 pb is excluded at 90%CL for a WIMP mass of 80 GeV/c2. This result demonstrates for the first time the very high background rejection capabilities of these simple and robust detectors in an actual WIMP search experiment.
The technology of scintillating bolometers based on zinc molybdate (ZnMoO\(_4\)) crystals is under development within the LUMINEU project to search for 0\(\nu\)2\(\beta\) decay of \(^{100}\)Mo with ...the goal to set the basis for large scale experiments capable to explore the inverted hierarchy region of the neutrino mass pattern. Advanced ZnMoO\(_4\) crystal scintillators with mass of \(\sim\)~0.3 kg were developed and Zn\(^{100}\)MoO\(_4\) crystal from enriched \(^{100}\)Mo was produced for the first time by using the low-thermal-gradient Czochralski technique. One ZnMoO\(_4\) scintillator and two samples (59 g and 63 g) cut from the enriched boule were tested aboveground at milli-Kelvin temperature as scintillating bolometers showing a high detection performance. The first results of the low background measurements with three ZnMoO\(_4\) and two enriched detectors installed in the EDELWEISS set-up at the Modane Underground Laboratory (France) are presented.
A new design of a cryogenic germanium detector for dark matter search is presented, taking advantage of the coplanar grid technique of event localisation for improved background discrimination. ...Experiments performed with prototype devices in the EDELWEISS II setup at the Modane underground facility demonstrate the remarkably high efficiency of these devices for the rejection of low-energy \(\beta\), approaching 10\(^5\) . This opens the road to investigate the range beyond 10\(^{-8}\) pb in the WIMP-nucleon collision cross-sections, as proposed in the EURECA project of a one-ton cryogenic detector mass.
This study aimed to explore whether a computerized cognitive stimulation program (CCS) induced differential effects in older adults with mild cognitive impairment (MCI) according to the severity of ...white matter hyperintensities (WMH), which are associated with cognitive impairment and increased risk of progression to Alzheimer's disease because of the damage they cause to cortical and subcortical networks.
Twenty-nine MCI patients with no or little WMH (MCI-non-WMH) and 22 MCI patients with moderate or severe WMH (MCI-WMH) attended a 24-session CCS program (two sessions per week for a duration of 3 months) focused on executive functions, attention, and processing speed. Cognitive and psychosocial assessments were performed at baseline, postintervention, and 3 months after the intervention.
Both groups improved on several cognitive measures after the intervention. However, the MCI-non-WMH group improved on a higher number of cognitive measures than the MCI-WMH group. At postintervention assessment, CCS had a more beneficial effect on the MCI-non-WMH group than on the MCI-WMH group with regard to improving categorical fluency (4.6±6.8 vs 0.4±6.4; effect size=0.37;
=0.002). During the 3-month follow-up assessment, significantly higher score improvements were observed in the MCI-non-WMH group for the paired-associate learning test (6.4±3 vs 4.7±3.5 points; effect size=0.43;
=0.005) as well as categorical fluency (3.8±7.8 vs -0.7±6 points; effect size=0.55;
=0.0003).
These findings suggest that WMH severity was related to cognitive improvement induced by a CCS program and highlight the importance of considering WMH in interventional studies on subjects with MCI.
L’article présente des résultats sur la compréhension de la mort des végétaux de 40 enfants de six et de dix ans, appréhendée grâce à trois types de questionnements : des questions fermées sur la ...généralisation de la mort, des questions ouvertes sur les causes invoquées et des questions à choix de raisonnements (intentionnel, téléologique, vitaliste, essentialiste). Les résultats valident la plupart de nos hypothèses sur l’effet de la typicalité des végétaux et le choix d’explications vitalistes, surtout pour les plus jeunes, contrairement au raisonnement essentialiste plus abstrait, parce que faisant référence à des facteurs internes, plus fréquent chez les enfants de dix ans que chez ceux de six ans. Cette étude s’inscrit dans une approche actuelle du développement conceptuel.
This paper presents results of a study about the knowledge of plants’ death from 40 children of six and ten year-old. Three kinds of measures were available: questions about plants’ death according to typicality, free questions on causes of death and attributions of several kinds of explanations (intentional, teleological, vitalistic and essentialist). Results validated almost all our hypotheses, because typicality appeared to have an influence on the generalisation of death, and young children had more a vitalistic thinking more linked to feeding then essentialism which is more abstract. Such a way of reasoning was most frequent in older children. This kind of study belongs to a current theoretical approach of conceptual development.
PDF
