1,407 research outputs found
Magnetic properties of the honeycomb oxide NaCoTeO
We have studied the magnetic properties of NaCoTeO, which
features a honeycomb lattice of magnetic Co ions, through macroscopic
characterization and neutron diffraction on a powder sample. We have shown that
this material orders in a zig-zag antiferromagnetic structure. In addition to
allowing a linear magnetoelectric coupling, this magnetic arrangement displays
very peculiar spatial magnetic correlations, larger in the honeycomb planes
than between the planes, which do not evolve with the temperature. We have
investigated this behavior by Monte Carlo calculations using the
-- model on a honeycomb lattice with a small interplane
interaction. Our model reproduces the experimental neutron structure factor,
although its absence of temperature evolution must be due to additional
ingredients, such as chemical disorder or quantum fluctuations enhanced by the
proximity to a phase boundary.Comment: 9 pages, 13 figure
Magnetic order in the frustrated Ising-like chain compound SrNiIrO
We have studied the field and temperature dependence of the magnetization of
single crystals of Sr3NiIrO6. These measurements evidence the presence of an
easy axis of anisotropy and two anomalies in the magnetic susceptibility.
Neutron powder diffraction realized on a polycrystalline sample reveals the
emergence of magnetic reflections below 75 K with magnetic propagation vector k
~ (0, 0, 1), undetected in previous neutron studies [T.N. Nguyen and H.-C zur
Loye, J. Solid State Chem., 117, 300 (1995)]. The nature of the magnetic ground
state, and the presence of two anomalies common to this family of material, are
discussed on the basis of the results obtained by neutron diffraction,
magnetization measurements, and symmetry arguments
Anisotropic interactions opposing magnetocrystalline anisotropy in SrNiIrO
We report our investigation of the electronic and magnetic excitations of
SrNiIrO by resonant inelastic x-ray scattering at the Ir L edge.
The intra- electronic transitions are analyzed using an atomic model,
including spin-orbit coupling and trigonal distortion of the IrO
octahedron, confronted to {\it ab initio} quantum chemistry calculations. The
Ir spin-orbital entanglement is quantified and its implication on the magnetic
properties, in particular in inducing highly anisotropic magnetic interactions,
is highlighted. These are included in the spin-wave model proposed to account
for the dispersionless magnetic excitation that we observe at 90 meV. By
counterbalancing the strong Ni easy-plane anisotropy that manifests
itself at high temperature, the anisotropy of the interactions finally leads to
the remarkable easy-axis magnetism reported in this material at low
temperature
Analysis of residual content of used syringes collected from low threshold facilities in Lausanne, Switzerland.
For the first time in Switzerland, an analysis of residual contents from used syringes collected from low threshold facilities was performed. This preliminary study is part of a wider project aiming to understand patterns of injecting drug use over time.
Among the 100,000 syringes exchanged annually by the ABS foundation (Accueil Bas Seuil), 113 were collected following a purposive sampling method and analysed by gas chromatography coupled with mass spectrometry (GC-MS).
Four syringes (4% of the sample population) contained no substances take into consideration the limit of the method. Cocaine was the most commonly observed compound and was detected in 77 syringes (68%), whilst users reported syringes with cocaine among those analysed in this study. Heroin was detected in 49 syringes (43%) and reported by 53 users returning syringes; midazolam was detected in 31 syringes (27%) and reported as the medicine Dormicum(®) in 22 occurrences. No new or unusual illicit drug was detected in the sample.
The results show the presence of cocaine in more than half of the sample, an absence of new or unusual illicit drugs, as well as very few traces of methadone, which suggests that this substitution drug is rarely injected. This preliminary study also demonstrates the potential of this developed methodology for monitoring purposes. An ongoing and more systematic approach could allow to detect modifications in drug use patterns among the target population as well as the appearance of new and hazardous substances. Such systematic and timely results could allow an adaptation of harm reduction interventions
An approach to map geography mark-up language data to resource description framework schema
GML serves as premier modeling language used to represent data of geographic information related to geography locations. However, a problem of GML is its ability to integrate with a variety of geographical and GPS applications. Since, GML saves data in coordinates and in topology for the purpose to integrate data with variety of applications on semantic web, data be mapped to Resource Description Framework (RDF) and Resource Description Framework Schema (RDFS). An approach of mapping GML metadata to RDFS is presented in this paper. This study focuses on the methodology to convert GML data in semantics to represent in extended and enriched form such as RDFS as representation in RDF is not sufficient over semantic web. Firstly, we have GML script from case study and parse it using GML parser and get XML file. XML file parse using Java and get text file to extract GML features and then get a graph form of these features. After that we designed methodology of prototype tool to map GML features to RDFS. Tool performed features by features mapping and extracted results are represented in the tabular form of mapping GML metadata to RDFS. © 2020, Springer Nature Singapore Pte Ltd.E
MISE EN PLACE D’UNE DÉMARCHE QUALITÉ DANS LE CADRE DE L’ÉCHANTILLONNAGE D’UNE POPULATION DE GRANDE ALOSE (ALOSA ALOSA).
National audienceIf the protocols of data acquisition are not formalized enough, in ecology or in population dynamics, we run the risk that, with time and different operators, there will be a non-measurable drift. The consequences may be serious when it comes to interpretations. To limit these risks, we have tried to standardize all stages of sampling data acquisition on functioning of the Alosa alosa population in the Gironde Garonne Dordogne drainage basin. After a detailed analysis of the acquisition stage, we have split it into 3 main parts: the sampling procedure, the operative mode of sampling in the field and the operative mode of cleaning and mounting scales in the laboratory. Each part is shown chronologically; each task is explained and the exact path of information is specified throughout the transcriber chain (fish, scales, and data). Supplementary difficulties are essentially due to the time necessary to write the protocol in due form. On the other hand, at the moment of the carrying out the study, security and standardization save time for the data reliability.Pour éviter les risques de dérives méthodologiques ou d'hétérogénéité au fil du temps ou des opérateurs il est nécessaire pour une bonne qualité des travaux réalisés en écologie comme en dynamique des populations de disposer de protocoles d'acquisition de données formalisés suffisamment détaillés. Dans le cadre de l'analyse du fonctionnement de la population de grande alose Alosa alosa du bassin versant Gironde Garonne Dordogne (France) nous avons mené un travail de standardisation des différentes étapes de l'acquisition des données d'échantillonnage. Après une analyse détaillée et exhaustive de la démarche d'acquisition nous avons identifié trois parties : la procédure d'échantillonnage, le mode opératoire des prélèvements sur le terrain et le mode opératoire de la préparation et du montage des écailles au laboratoire. Chacune de ces parties est présentée chronologiquement, le cheminement de l'information est précisé au long de la chaîne des transcripteurs (poissons, écailles, données) et certaines étapes clés sont précisées à titre d'illustration. Les contraintes supplémentaires engendrées par cette formalisation sont essentiellement dues au temps requis pour la rédaction des protocoles selon les normes de l'assurance qualité ; en revanche au cours de la réalisation de l'étude cette démarche apporte un gain de temps et une amélioration de fiabilité des données en la sécurisant et en la standardisant. C'est également une étape indispensable pour envisager l'accréditation de laboratoire
Are N=1 and N=2 supersymmetric quantum mechanics equivalent?
After recalling different formulations of the definition of supersymmetric
quantum mechanics given in the literature, we discuss the relationships between
them in order to provide an answer to the question raised in the title.Comment: 15 page
Study of a Solution with COTS for the LHCb Calorimeter Upgrade
AbstractWe present a solution made out of Components Out of Shelf (COTS) for the analog processing of the signal of the LHCb calorimeters in the framework of the foreseen upgrade of the detector. The present proposal is based on the current functional solution, yet, to meet the stringent noise requirements, a number of modifications are proposed. Preliminary results on the prototype boards show promising results
Data-Driven Audiogram Classification for Mobile Audiometry
Recent mobile and automated audiometry technologies have allowed for the democratization of hearing healthcare and enables non-experts to deliver hearing tests. The problem remains that a large number of such users are not trained to interpret audiograms. In this work, we outline the development of a data-driven audiogram classification system designed specifically for the purpose of concisely describing audiograms. More specifically, we present how a training dataset was assembled and the development of the classification system leveraging supervised learning techniques. We show that three practicing audiologists had high intra- and inter-rater agreement over audiogram classification tasks pertaining to audiogram configuration, symmetry and severity. The system proposed here achieves a performance comparable to the state of the art, but is signific
Polarization resolved Cu -edge resonant inelastic x-ray scattering of orbital and spin excitations in NdBaCuO
High resolution resonant inelastic x-ray scattering (RIXS) has proven
particularly effective in the determination of crystal field and spin
excitations in cuprates. Its strength lies in the large Cu resonance
and in the fact that the scattering cross section follows quite closely the
single-ion model predictions, both in the insulating parent compounds and in
the superconducting doped materials. However, the spectra become increasingly
broader with (hole) doping, hence resolving and assigning spectral features has
proven challenging even with the highest energy resolution experimentally
achievable. Here we have overcome this limitation by measuring the complete
polarization dependence of the RIXS spectra as function of momentum transfer
and doping in thin films of NdBaCuO. Besides
confirming the previous assignment of and spin excitations (magnon,
bimagnon) in the antiferromagnetic insulating parent compound, we unequivocally
single out the actual spin-flip contribution at all dopings. We also
demonstrate that the softening of excitations is mainly attributed to the
shift of the peak to lower energy loss. These results provide a definitive
assessment of the RIXS spectra of cuprates and demonstrate that RIXS
measurements with full polarization control are practically feasible and highly
informative.Comment: 14 pages, 10 figure
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