10,226 research outputs found
Do halos exist on the dripline of deformed nuclei?
A study of the effect of deformation and pairing on the development of halo
nuclei is presented. Exploratory three-body calculations show that
both the NN interaction and the deformation/excitation of the core hinder the
formation of the halo. Preliminary self-consistent mean-field calculations are
used to search for regions in the nuclear chart where halos could potentially
develop. These are also briefly discussed.Comment: 5 pages and 3 figures, proceedings for CGS1
Cerebral and cardiovascular effects of analgesic doses of ketamine during a target controlled general anesthesia: a prospective randomized study
Introduction: Ketamine is increasingly being used in various pain settings. The purpose of this study was to
assess the effect of an analgesic dose of ketamine in the bispectral index (BIS), spectral edge frequency (SEF-95), density spectral array (DSA), cerebral oximetry (rSO2) and mean arterial pressure (MAP) during general
anaesthesia with a target controlled infusion.
Methods: A prospective, single-blinded and randomized study on adult patients scheduled for elective spine
surgery was carried out. After anaesthesia induction with propofol, remifentanil and rocuronium, when a stable BIS
value (45-55) was achieved, an automatic recording of BIS, SEF-95, rSO2 and MAP values during 9 min was
performed to establish patients baseline values. Subsequently, patients were randomly assigned to receive a
ketamine bolus dose of 0.2 mg/kg, 0.5 mg/kg or 1 mg/kg; all variables were recorded for additional 9 min after the
ketamine bolus, in the absence of any surgical stimulus. A p-value <0.05 was considered significant in the statistical
analysis.
Results and discussion: Thirty-nine patients were enrolled in the study. Our results show a dose-related
increase of SEF-95 and BIS values. DSA demonstrate a shift in the frequency range and power distribution towards
higher frequencies. Our results do not show significant differences in MAP and rSO2 values.
Conclusion: When ketamine is used intraoperatively in analgesic doses, the anaesthetist should anticipate an
increase in SEF-95 and BIS values which will not be associated with the level of anaesthesia.info:eu-repo/semantics/publishedVersio
On the particle spectrum and the conformal window
We study the SU(3) gauge theory with twelve flavours of fermions in the
fundamental representation as a prototype of non-Abelian gauge theories inside
the conformal window. Guided by the pattern of underlying symmetries, chiral
and conformal, we analyze the two-point functions theoretically and on the
lattice, and determine the finite size scaling and the infinite volume fermion
mass dependence of the would-be hadron masses. We show that the spectrum in the
Coulomb phase of the system can be described in the context of a universal
scaling analysis and we provide the nonperturbative determination of the
fermion mass anomalous dimension gamma*=0.235(46) at the infrared fixed point.
We comment on the agreement with the four-loop perturbative prediction for this
quantity and we provide a unified description of all existing lattice results
for the spectrum of this system, them being in the Coulomb phase or the
asymptotically free phase. Our results corroborate the view that the fixed
point we are studying is not associated to a physical singularity along the
bare coupling line and estimates of physical observables can be attempted on
either side of the fixed point. Finally, we observe the restoration of the U(1)
axial symmetry in the two-point functions.Comment: 40 pages, 22 figure
One,Two,Zero: Scales of Strong Interactions
We discuss our results on QCD with a number of fundamental fermions ranging
from zero to sixteen. These theories exhibit a wide array of fascinating
phenomena which have been under close scrutiny, especially in recent years,
first and foremost is the approach to conformality. To keep this review
focused, we have chosen scale generation, or lack thereof as a guiding theme,
however the discussion will be set in the general framework of the analysis of
the phases and phase transitions of strong interactions at zero and nonzero
temperature.Comment: 15 pages, prepared for IJMPA Special Issue 'Recent Nonperturbative
Developments in QCD-like Theories
Chiral symmetry restoration in QCD with many flavours
We discuss the phases of QCD in the parameter space spanned by the number of
light flavours and the temperature with respect to the realisation of chiral
and conformal symmetries. The intriguing interplay of these symmetries is best
studied by means of lattice simulations, and some selected results from our
recent work are presented here.Comment: 10 pages, proceedings of the 9th International Workshop on Critical
Point and Onset of Deconfinement, 17-21 November, 2014, ZiF, Bielefeld,
German
Mass freezing in growing neutrino quintessence
Growing neutrino quintessence solves the coincidence problem for dark energy
by a growing cosmological value of the neutrino mass which emerges from a
cosmon-neutrino interaction stronger than gravity. The cosmon-mediated
attraction between neutrinos induces the formation of large scale neutrino
lumps in a recent cosmological epoch. We argue that the non-linearities in the
cosmon field equations stop the further increase of the neutrino mass within
sufficiently dense and large lumps. As a result, we find the neutrino induced
gravitational potential to be substantially reduced when compared to linear
extrapolations. We furthermore demonstrate that inside a lump the possible time
variation of fundamental constants is much smaller than their cosmological
evolution. This feature may reconcile current geophysical bounds with claimed
cosmological variations of the fine structure constant.Comment: 15 pages, 12 figures. Version published in PR
All-optical high speed NOR gate based on two photon absorption in silicon wire waveguides
We demonstrate for the first time an all-optical logic NOR gate in submicron size silicon wire waveguides. High speed operation at equivalent 80Gbps data rate was achieved using pump induced non-degenerate two-photon absorption inside the waveguides. The device requires low pulse energy (few pJ) for logic gate operation. (C) 2005 Optical Society of America
Synthesis of sub-5 nm Co-doped SnO nanoparticles and their structural, microstructural, optical and photocatalytic properties
A swift chemical route to synthesize Co-doped SnO nanopowders is
described. Pure and highly stable SnCoO (0 x
0.15) crystalline nanoparticles were synthesized, with mean grain sizes <
5 nm and the dopant element homogeneously distributed in substitutional sites
of the SnO matrix. The UV-visible diffuse reflectance spectra of the
SnCoO samples reveal red shifts, the optical bandgap
energies decreasing with increasing Co concentration. The Urbach energies of
the samples were calculated and correlated with their bandgap energies. The
photocatalytic activity of the SnCoO samples was
investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A
complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02%
(w/w) of SnCoO nanoparticles in 60 min of
irradiation.Comment: 29 pages, 2 tables, 10 figure
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