149 research outputs found
The influence of mercury vapor on the electrical resistance of chalcogenide amorphous films
Using the planar structures "Ni layer - chalcogenide amorphous film - Ni layer" and "graphite probe - chalcogenide amorphous film graphite probe" samples, the influence of mercury vapor on the electrical resistance of amorphous films of the Se-Te, Se-Sb and Se-As systems was investigated. It was established that exposure of samples in mercury vapor leads to a decrease in their electrical resistance by 4-7 orders of magnitude. As the temperature and mercury concentration increase, the transition time from a high-resistance state to a low-resistance state decreases. When introducing Te, Sb, and As into amorphous selenium and increasing their concentration in the composition of the films, the transition time increases, and the value of the change in resistance decreases. It was established that the change in resistance is mainly determined by the change in surface conductivity of chalcogenide films. A decrease in the electrical resistance of selenium-containing amorphous films modified with mercury is caused by the formation of HgSe crystalline inclusions in their matrix
Capacitively Enhanced Thermal Escape in Underdamped Josephson Junctions
We have studied experimentally the escape dynamics in underdamped
capacitively shunted and unshunted Josephson junctions with submicroampere
critical currents below 0.5 K temperatures. In the shunted junctions, thermal
activation process was preserved up to the highest temperature where the escape
in the unshunted junctions exhibits the phase diffusion. Our observations in
the shunted junctions are in good agreement with the standard thermal
activation escape, unlike the results in the unshunted junctions.Comment: 4 pages, 3 figure
Paradoxical effect of baclofen on social behavior in the fragile X syndrome mouse model
Introduction: Fragile X syndrome (FXS) is a common monogenetic cause of intellectual disability, autism spectrum features, and a broad range of other psychiatric and medical problems. FXS is caused by the lack of the fragile X mental retardation protein (FMRP), a translational regulator of specific mRNAs at the postsynaptic compartment. The absence of FMRP leads to aberrant synaptic plasticity, which is believed to be caused by an imbalance in excitatory and inhibitory network functioning of the synapse. Evidence from studies in mice demonstrates that GABA, the major inhibitory neurotransmitter in the brain, and its receptors, is involved in the pathogenesis of FXS. Moreover, several FXS phenotypes, including social behavior deficits, could be corrected in Fmr1 KO mice after acute treatment with GABAB agonists. Methods: As FXS would probably require a lifelong treatment, we investigated the effect of chronic treatment with the GABAB agonist baclofen on social behavior in Fmr1 KO mice on two behavioral paradigms for social behavior: the automated tube test and the three-chamber sociability test. Results: Unexpectedly, chronic baclofen treatment resulted in worsening of the FXS phenotypes in these behavior tests. Strikingly, baclofen treatment also affected wild-type animals in both behavioral tests, inducing a phenotype similar to that of untreated Fmr1 KO mice. Conclusion: Altogether, the disappointing results of recent clinical trials with the R-baclofen enantiomer arbaclofen and our current results indicate that baclofen should be reconsidered and further evaluated before its application in targeted treatment for FXS
Strangeness Enhancement in and Interactions at SPS Energies
The systematics of strangeness enhancement is calculated using the HIJING and
VENUS models and compared to recent data on , and
collisions at CERN/SPS energies (). The HIJING model is used to
perform a {\em linear} extrapolation from to . VENUS is used to
estimate the effects of final state cascading and possible non-conventional
production mechanisms. This comparison shows that the large enhancement of
strangeness observed in collisions, interpreted previously as possible
evidence for quark-gluon plasma formation, has its origins in non-equilibrium
dynamics of few nucleon systems. % Strangeness enhancement %is therefore traced
back to the change in the production dynamics %from to minimum bias
and central collisions. A factor of two enhancement of at
mid-rapidity is indicated by recent data, where on the average {\em one}
projectile nucleon interacts with only {\em two} target nucleons. There appears
to be another factor of two enhancement in the light ion reaction relative
to , when on the average only two projectile nucleons interact with two
target ones.Comment: 29 pages, 8 figures in uuencoded postscript fil
ϒ production in p–Pb collisions at √sNN=8.16 TeV
ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio
(Anti-)deuteron production in pp collisions at 1as=13TeV
The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at s=13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (d Nch/ d \u3b7 3c 26) as measured in p\u2013Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p\u2013Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and statistical hadronisation models (SHM)
Multiplicity dependence of inclusive J/psi production at midrapidity in pp collisions at root s=13 TeV
Measurements of the inclusive J/psi yield as a function of charged-particle pseudorapidity density dN(ch)/d eta in pp collisions at root s = 13 TeV with ALICE at the LHC are reported. The J/psi meson yield is measured at midrapidity (vertical bar y vertical bar <0.9) in the dielectron channel, for events selected based on the charged-particle multiplicity at midrapidity (vertical bar eta vertical bar <1) and at forward rapidity (-3.7 <eta <-1.7 and 2.8 <eta <5.1); both observables are normalized to their corresponding averages in minimum bias events. The increase of the normalized J/psi yield with normalized dN(ch)/d eta is significantly stronger than linear and dependent on the transverse momentum. The data are compared to theoretical predictions, which describe the observed trends well, albeit not always quantitatively. (C) 2020 European Organization for Nuclear Research. Published by Elsevier B.V.Peer reviewe
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