55 research outputs found

    Disordered Systems and the Replica Method in AdS/CFT

    Full text link
    We formulate a holographic description of effects of disorder in conformal field theories based on the replica method and the AdS/CFT correspondence. Starting with nn copies of conformal field theories, randomness with a gaussian distribution is described by a deformation of double trace operators. After computing physical quantities, we take the n0n \to 0 limit at the final step. We compute correlation functions in the disordered systems by using the holographic replica method as well as the formulation in the conformal field theory. We find examples where disorder changes drastically the scaling of two point functions. The renormalization group flow of the effective central charge in our disordered systems is also discussed.Comment: 26 pages, references added, published versio

    The holographic superconductors in higher-dimensional AdS soliton

    Full text link
    We explore the behaviors of the holographic superconductors at zero temperature for a charged scalar field coupled to a Maxwell field in higher-dimensional AdS soliton spacetime via analytical way. In the probe limit, we obtain the critical chemical potentials increase linearly as a total dimension dd grows up. We find that the critical exponent for condensation operator is obtained as 1/2 independently of dd, and the charge density is linearly related to the chemical potential near the critical point. Furthermore, we consider a slightly generalized setup the Einstein-Power-Maxwell field theory, and find that the critical exponent for condensation operator is given as 1/(42n)1/(4-2n) in terms of a power parameter nn of the Power-Maxwell field, and the charge density is proportional to the chemical potential to the power of 1/(2n)1/(2-n).Comment: LaTeX, 16 pages, 5 figures, typos corrected, one reference added, version to appear in European Physical Journal

    Some No-go Theorems for String Duals of Non-relativistic Lifshitz-like Theories

    Full text link
    We study possibilities of string theory embeddings of the gravity duals for non-relativistic Lifshitz-like theories with anisotropic scale invariance. We search classical solutions in type IIA and eleven-dimensional supergravities which are expected to be dual to (2+1)-dimensional Lifshitz-like theories. Under reasonable ansaetze, we prove that such gravity duals in the supergravities are not possible. We also discuss a possible physical reason behind this.Comment: 18 pages, Latex, flux conditions clarified (v2), brief summary of results added (v3

    Thermodynamics and classification of cosmological models in the Horava-Lifshitz theory of gravity

    Full text link
    We study thermodynamics of cosmological models in the Horava-Lifshitz theory of gravity, and systematically investigate the evolution of the universe filled with a perfect fluid that has the equation of state p=wρp=w\rho, where pp and ρ\rho denote, respectively, the pressure and energy density of the fluid, and ww is an arbitrary real constant. Depending on specific values of the free parameters involved in the models, we classify all of them into various cases. In each case the main properties of the evolution are studied in detail, including the periods of deceleration and/or acceleration, and the existence of big bang, big crunch, and big rip singularities. We pay particular attention on models that may give rise to a bouncing universe.Comment: revtex4, 21 figures. New references added & some changes made in Introduction. Version to appear in JCA

    Opposing authigenic controls on the isotopic signature of dissolved iron in hydrothermal plumes

    Get PDF
    Iron is a scarce but essential micronutrient in the oceans that limits primary productivity in many regions of the surface ocean. The mechanisms and rates of Fe supply to the ocean interior are still poorly understood and quantified. Iron isotope ratios of different Fe pools can potentially be used to trace sources and sinks of the global Fe biogeochemical cycle if these boundary fluxes have distinct signatures. Seafloor hydrothermal vents emit metal rich fluids from mid-ocean ridges into the deep ocean. Iron isotope ratios have the potential to be used to trace the input of hydrothermal dissolved iron to the oceans if the local controls on the fractionation of Fe isotopes during plume dispersal in the deep ocean are understood. In this study we assess the behaviour of Fe isotopes in a Southern Ocean hydrothermal plume using a sampling program of Total Dissolvable Fe (TDFe), and dissolved Fe (dFe). We demonstrate that δ56Fe values of dFe (δ56dFe) within the hydrothermal plume change dramatically during early plume dispersal, ranging from −2.39 ± 0.05‰ to −0.13 ± 0.06‰ (2 SD). The isotopic composition of TDFe (δ56TDFe) was consistently heavier than dFe values, ranging from −0.31 ± 0.03‰ to 0.78 ± 0.05‰, consistent with Fe oxyhydroxide precipitation as the plume samples age. The dFe present in the hydrothermal plume includes stabilised dFe species with potential to be transported to the deep ocean. We estimate that stable dFe exported from the plume will have a δ56Fe of −0.28 ± 0.17‰. Further, we show that the proportion of authigenic iron-sulfide and iron-oxyhydroxide minerals precipitating in the buoyant plume exert opposing controls on the resultant isotope composition of dissolved Fe passed into the neutrally buoyant plume. We show that such controls yield variable dissolved Fe isotope signatures under the authigenic conditions reported from modern vent sites elsewhere, and so ought to be considered during iron isotope reconstructions of past hydrothermalism from ocean sediment records

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

    Get PDF
    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Lance-headed viper (Bothrops moojeni) bite wounding the eye Acidente botrópico (Bothrops moojeni) com ferimento ocular

    No full text
    A 5-year-old girl was bitten in her left eye by a lance-headed viper identified as Bothrops moojeni, measuring 115 cm of length. There was severe facial swelling and left exophthalmus, and enucleation of the eye was necessary. The patient apparently had mild systemic envenoming, but local inflammatory signs and histological evidence of necrosis suggest that both the mechanical trauma and the local action of the venom had a role in the genesis of the eye lesion. It is arguable if the loss of the eye could be prevented even if the antivenom was administered earlier.<br>Uma menina de 5 anos de idade foi picada no olho esquerdo por uma serpente da espécie Bothrops moojeni, que media 115 cm de comprimento. Houve intenso edema facial e ex-oftalmia; enucleação do olho foi necessária. A paciente aparentemente apresentou um envenenamento sistêmico leve, mas os sinais inflamatórios locais e a evidência histológica de necrose sugerem que tanto o traumatismo mecânico como a ação local do veneno tiveram um papel na gênese da lesão ocular. É questionável se o prognóstico da lesão ocular teria sido diferente se o antiveneno tivesse sido administrado em dose adequada mais precocemente

    Agreement between premortem and postmortem diagnoses in patients with acquired immunodeficiency syndrome observed at a brazilian teaching hospital

    No full text
    Acquired immunodeficiency syndrome (AIDS) is one of the main causes of death in adults worldwide. More commonly than in the general population, in patients with AIDS there is substantial disagreement between causes of death which are clinically suspected and those established by postmortem examination. The findings of 52 postmortem examinations were compared to the premortem (clinical) diagnoses, and there was 46% agreement between them. Fifty two percent of the patients had more than one postmortem diagnosis, and 48% had at least one AIDS-related disease not suspected clinically. Cytomegalovirus infection was the commonest (30.7%) autopsy finding, but not a single case had been suspected premortem. Bacterial infection, tuberculosis, and histoplasmosis were also common, sometimes not previously suspected, postmortem findings. This study shows that multiple infections occur simultaneously in AIDS patients, and that many among them are never suspected before the postmortem examination. These findings suggest that an aggressive investigation of infections and cancers should be done in patients with AIDS, particularly in those who do not respond to therapy of an already recognized condition<br>Concordância entre diagnósticos clínicos e de necrópsia em pacientes com síndrome da imunodeficiência adquirida observados em um hospital universitário brasileiro A síndrome da imunodeficiência adquirida (SIDA) é uma das principais causas de morte em adultos em todo mundo. Com maior freqüência do que ocorre na população geral, há em pacientes com SIDA uma substancial discordância entre as causas de morte clinicamente suspeitadas e as estabelecidas pelas autópsias. Revisamos os achados de 52 necrópsias de pacientes com SIDA e seus respectivos diagnósticos clínicos, e encontramos 46% de concordância entre eles. Cinquenta e dois por cento dos pacientes tiveram mais de um diagnóstico necroscopicamente definido e 48% tiveram pelo menos uma doença relacionada à SIDA, não suspeitada clinicamente. Infecção pelo citomegalovírus foi o achado necroscópico mais comum (30,7%) e em nenhum dos casos o diagnóstico foi suspeitado em vida. Infecção bacteriana, tuberculose, e histoplasmose foram também achados freqüentes de necrópsia, por vezes não suspeitados anteriormente. Este estudo demonstra que múltiplas infecções ocorrem simultaneamente em pacientes com SIDA, sendo que muitas delas sequer são suspeitadas clinicamente. Estes achados sugerem que investigação agressiva de infecções e neoplasias deva ser feita em pacientes com SIDA, particularmente naqueles que não respondem ao tratamento de uma patologia já diagnosticad
    corecore