628 research outputs found

    Information measures of hydrogenic systems, Laguerre polynomials and spherical harmonics

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    AbstractFisher's information and Shannon's entropy are two complementary information measures of a probability distribution. Here, the probability distributions which characterize the quantum-mechanical states of a hydrogenic system are analyzed by means of these two quantities. These distributions are described in terms of Laguerre polynomials and spherical harmonics, whose characteristics are controlled by the three integer quantum numbers of the corresponding states. We have found the explicit expression for the Fisher information, and a lower bound for the Shannon entropy with the help of an isoperimetric inequality

    First Record Along The Uruguayan Coast Of The Largest Sea Nettle Jellyfish, Chrysaora Plocamia (lesson, 1830) (cnidaria: Scyphozoa)

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    Chrysaora plocamia is one of the 15 species of the jellyfish genus Chrysaora. This species has an unusualdistribution pattern, occurring on both Atlantic and Pacific coasts of South America. It is distributed along the southeastern Pacific Ocean, encompassing coastal areas of Peru and Chile, and reaching the Patagonian coast of Argentina in the southwestern Atlantic. During two separate events, two large specimens of Chrysaora were collected on the east coast of Uruguay at La Paloma. Based on morphology and molecular data, these specimens were identified as Chrysaora plocamia. These records are described along with oceanographic features observed at that time. Unusual oceanographic and atmospheric conditions may explain the presence of these specimens 1,100 km north of the current northernmost known distribution. © 2016 Check List and Authors.12

    Configuration Complexities of Hydrogenic Atoms

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    The Fisher-Shannon and Cramer-Rao information measures, and the LMC-like or shape complexity (i.e., the disequilibrium times the Shannon entropic power) of hydrogenic stationary states are investigated in both position and momentum spaces. First, it is shown that not only the Fisher information and the variance (then, the Cramer-Rao measure) but also the disequilibrium associated to the quantum-mechanical probability density can be explicitly expressed in terms of the three quantum numbers (n, l, m) of the corresponding state. Second, the three composite measures mentioned above are analytically, numerically and physically discussed for both ground and excited states. It is observed, in particular, that these configuration complexities do not depend on the nuclear charge Z. Moreover, the Fisher-Shannon measure is shown to quadratically depend on the principal quantum number n. Finally, sharp upper bounds to the Fisher-Shannon measure and the shape complexity of a general hydrogenic orbital are given in terms of the quantum numbers.Comment: 22 pages, 7 figures, accepted i

    Maximal Violation of Bell Inequalities using Continuous Variables Measurements

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    We propose a whole family of physical states that yield a violation of the Bell CHSH inequality arbitrarily close to its maximum value, when using quadrature phase homodyne detection. This result is based on a new binning process called root binning, that is used to transform the continuous variables measurements into binary results needed for the tests of quantum mechanics versus local realistic theories. A physical process in order to produce such states is also suggested. The use of high-efficiency spacelike separated homodyne detections with these states and this binning process would result in a conclusive loophole-free test of quantum mechanics.Comment: 7 pages, 5 figures, to appear in PRA in a slightly different versio

    Drude model and Lifshitz formula

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    Since nearly 10 years, it is known that inserting the permittivity of the Drude model into the Lifshitz formula for free energy causes a violation of the third law of thermodynamics. In this paper we show that the standard Matsubara formulation for free energy contains a contribution that is non-perturbative in the relaxation parameter. We argue that the correct formula must have a perturbative expansion and conclude that the standard Matsubara formulation with the permittivity of the Drude model inserted is not correct. We trace the non-perturbative contribution in the complex frequency plane, where it shows up as a self-intersection or a bifurcation of the integration path.Comment: accepted for publication in EPJ

    Implant of Port-o-Cath for antineoplastic chemotherapy in a canine: case report

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    O Port-o-Cath é um cateter venoso central totalmente implantável, o qual permite a infusão de quimioterápicos, hemoderivados, nutrição parenteral e coleta de sangue. Este trabalho relata o caso de um canino com um tumor no membro pélvico que foi tratado cirurgicamente e recebeu o cateter para a quimioterapia antineoplásica. A paciente possuía um sarcoma sinovial, tumor incomum em cães, que acomete normalmente as articulações e exige terapia multimodal. O tratamento foi feito em duas etapas; na primeira, o membro foi amputado e, na segunda, foi realizado o implante do Port-o-Cath e exérese de nódulo metastático. A cadela respondeu satisfatoriamente à cirurgia e realizou as sessões de quimioterapia com perfeito funcionamento do cateter, indo a óbito por outras causas 90 dias após o procedimento. O implante de Port-o-Cath para a quimioterapia é um grande aliado à terapia multimodal preconizada para o câncer, podendo o cateter ser considerado em pacientes que necessitem de medicação quimioterápica por longo período.The Port-a-Cath is a totally implantable central venous catheter that allows the infusion of chemotherapeutic agents, blood products, parenteral nutrition, and blood sample collection. This work reports the case of a dog with a tumor in the pelvic limb that was treated surgically and received the catheter for cancer chemotherapy. The patient was diagnosed with synovial sarcoma, an uncommon tumor in dogs that usually affects the joints and requires multimodal therapy. The treatment was done in two steps, in the first the limb was amputated and in the second the Port-a-Cath implantation and the excision of the metastatic nodule were performed. The dog responded well to surgery and chemotherapy sessions held with proper functioning of the catheter, and died from other causes 90 days after the procedure. The implantation of Port-a-Cath for chemotherapy is a great ally of multimodal therapy recommended for cancer, so this catheter may be considered for patients requiring chemotherapy medication for a long period

    Leading order analysis of neutrino induced dimuon events in the CHORUS experiment

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    We present a leading order QCD analysis of a sample of neutrino induced charged-current events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. % with Eμ1,Eμ2>5E_{\mu 1},E_{\mu 2} > 5 GeV and Q2>3Q^2 > 3 GeV2^2 collected %between 1995 and 1998. The analysis yields a value of the charm quark mass of \mc = (1.26\pm 0.16 \pm 0.09) \GeVcc and a value of the ratio of the strange to non-strange sea in the nucleon of κ=0.33±0.05±0.05\kappa = 0.33 \pm 0.05 \pm 0.05, improving the results obtained in similar analyses by previous experiments.Comment: Submitted to Nuclear Physics

    Understanding CO oxidation reaction on platinum nanoparticles

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    To understand how the CO oxidation reaction proceeds on nanoparticles, which have complex surface structures, the behavior of the nanoparticles has to be related to that of single crystal electrodes with a well-defined surface structure. However, the direct extrapolation of the results is not possible because significant differences in the behavior between both type of surfaces are observed. In single crystal electrodes in both acidic and alkaline media, the reaction initiates on defects on the CO adlayer. These defects can be already present on the surface, as surface defects or steps, or generated during the formation of the CO adlayer. In the case of steps, the oxidation starts on the lower part of the step. The only difference between the reaction behavior between acidic and alkaline solutions is the lower mobility of the CO in alkaline solutions, which generates adlayers with higher number of defects and give rise to multiple stripping peaks in stepped surfaces. Using these results, the differences of the behavior between single crystal electrodes and nanoparticles can be rationalized. In spite of the fact that nanoparticles have small ordered domains, the presence of sites in which the reaction is initiated, equivalent to the site in the lower part of the step, is almost negligible, and thus, the oxidation reaction takes place at higher potential values than in stepped surfaces with similar domain size. Also the effect of nanoparticle agglomeration in the oxidation has been rationalized.This work has been financially supported by the MINECO-FEDER (projects CTQ 2013-44083-P and CTQ2013-48280-C3-3-R) and Generalitat Valenciana (project PROMETEO/2014/013). M.J.S. Farias acknowledges financial support from the CAPES – Brasil (PNPD)

    Charged-Particle Multiplicities in Charged-Current Neutrino-- and Anti-Neutrino--Nucleus Interactions

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    The CHORUS experiment, designed to search for νμντ\nu_{\mu}\to\nu_{\tau} oscillations, consists of a nuclear emulsion target and electronic detectors. In this paper, results on the production of charged particles in a small sample of charged-current neutrino-- and anti-neutrino--nucleus interactions at high energy are presented. For each event, the emission angle and the ionization features of the charged particles produced in the interaction are recorded, while the standard kinematic variables are reconstructed using the electronic detectors. The average multiplicities for charged tracks, the pseudo-rapidity distributions, the dispersion in the multiplicity of charged particles and the KNO scaling are studied in different kinematical regions. A study of quasi-elastic topologies performed for the first time in nuclear emulsions is also reported. The results are presented in a form suitable for use in the validation of Monte Carlo generators of neutrino--nucleus interactions.Comment: 17 pages, 5 figure

    Associated Charm Production in Neutrino-Nucleus Interactions

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    In this paper a search for associated charm production both in neutral and charged current ν\nu-nucleus interactions is presented. The improvement of automatic scanning systems in the {CHORUS} experiment allows an efficient search to be performed in emulsion for short-lived particles. Hence a search for rare processes, like the associated charm production, becomes possible through the observation of the double charm-decay topology with a very low background. About 130,000 ν\nu interactions located in the emulsion target have been analysed. Three events with two charm decays have been observed in the neutral-current sample with an estimated background of 0.18±\pm0.05. The relative rate of the associated charm cross-section in deep inelastic ν\nu interactions, σ(ccˉν)/σNCDIS=(3.622.42+2.95(stat)±0.54(syst))×103\sigma(c\bar{c}\nu)/\sigma_\mathrm{NC}^\mathrm{DIS}= (3.62^{+2.95}_{-2.42}({stat})\pm 0.54({syst}))\times 10^{-3} has been measured. One event with two charm decays has been observed in charged-current νμ\nu_\mu interactions with an estimated background of 0.18±\pm0.06 and the upper limit on associated charm production in charged-current interactions at 90% C.L. has been found to be σ(ccˉμ)/σCC<9.69×104\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}.Comment: 10 pages, 4 figure
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