92 research outputs found

    The Library of Babel

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    We show that heavy pure states of gravity can appear to be mixed states to almost all probes. Our arguments are made for AdS5\rm{AdS}_5 Schwarzschild black holes using the field theory dual to string theory in such spacetimes. Our results follow from applying information theoretic notions to field theory operators capable of describing very heavy states in gravity. For certain supersymmetric states of the theory, our account is exact: the microstates are described in gravity by a spacetime ``foam'', the precise details of which are invisible to almost all probes.Comment: 7 pages, 1 figure, Essay receiving honorable mention in the 2005 Gravity Research Foundation essay competitio

    Clinical spectrum of hypothyroidism: a cross sectional study in Puducherry, South India

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    Background: Hypothyroidism is characterised by underactive thyroid gland where there is reduced synthesis and secretion of thyroid hormones by the gland. With nearly one fifth of the population affected by hypothyroidism it is important to understand the clinical presentation of the disease. The present study aims to explore various clinical signs and symptoms of patients with hypothyroidism in Puducherry, South India.Methods: The study was carried out as a cross sectional study in a tertiary care medical college hospital, Puducherry among 213 patients who are admitted for various reasons and found to have hypothyroidism on laboratory investigations. With help of specialists in various fields all the patients were evaluated thoroughly and findings of the history and examination were noted down. Data entry was done in Epi Data version 3. Means and proportions were calculated using the software SPSS version 21.Results: Most of the hypothyroid patients (168/213) were females, giving a female: male ratio of approximately 3.4: 1. Primary hypothyroidism was found in most of the study participants (91%) and sub clinical hypothyroidism was seen in 6.2% of the patients. Commonest clinical presentation of the hypothyroid patients were fatigue (83.6%), weight gain (66.7%), were dry/coarse skin (52.1%) and voice change (50.7%).Conclusions: The commonest symptom being fatigue and weight gain while the commonest clinical sign was dry skin and voice change.

    Multi-Trace Superpotentials vs. Matrix Models

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    We consider N = 1 supersymmetric U(N) field theories in four dimensions with adjoint chiral matter and a multi-trace tree-level superpotential. We show that the computation of the effective action as a function of the glueball superfield localizes to computing matrix integrals. Unlike the single-trace case, holomorphy and symmetries do not forbid non-planar contributions. Nevertheless, only a special subset of the planar diagrams contributes to the exact result. Some of the data of this subset can be computed from the large-N limit of an associated multi-trace Matrix model. However, the prescription differs in important respects from that of Dijkgraaf and Vafa for single-trace superpotentials in that the field theory effective action is not the derivative of a multi-trace matrix model free energy. The basic subtlety involves the correct identification of the field theory glueball as a variable in the Matrix model, as we show via an auxiliary construction involving a single-trace matrix model with additional singlet fields which are integrated out to compute the multi-trace results. Along the way we also describe a general technique for computing the large-N limits of multi-trace Matrix models and raise the challenge of finding the field theories whose effective actions they may compute. Since our models can be treated as N = 1 deformations of pure N =2 gauge theory, we show that the effective superpotential that we compute also follows from the N = 2 Seiberg-Witten solution. Finally, we observe an interesting connection between multi-trace local theories and non-local field theory.Comment: 35 pages, LaTeX, 6 EPS figures. v2: typos fixed, v3: typos fixed, references added, Sec. 5 added explaining how multi-trace theories can be linearized in traces by addition of singlet fields and the relation of this approach to matrix model

    Simultaneous estimation of states and inputs in a planar solid oxide fuel cell using nonlinear adaptive observer design

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    An adaptive nonlinear observer design for the planar solid oxide fuel cell (SOFC) is presented in this work. This observer is based on a lumped parameter model of the SOFC and it can simultaneously estimate the inputs and the states of the system. Considering the inputs as unknown parameters is advantageous because some of the input parameters are not practically measurable in a SOFC stack. The asymptotic stability of the proposed observer is proven using the Lyapunov function method and is based on the concept of input-to-state stability for cascaded systems. The simulations show that the developed observer can track the temperature and species concentration profiles in the planar SOFC during step changes in the input variables and can simultaneously predict the input variables. The adaptive observer presented is valid for a wide operating range, requires fewer variables to be measured, and is robust to fluctuations in the input variables

    Clinical Profile and Outcomes of COVID-19 in Renal Transplant Recipients

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    There is minimal information on coronavirus disease 2019 (COVID-19) in developing countries regarding renal transplant recipients (RTRs). This paper aimed to study the clinical profile, immunosuppressive regimen, treatment, and outcomes in an RTR with COVID-19. This retrospective study was conducted in the nephrology department of Sri Aurobindo Medical College & Postgraduate Institute, Indore (MP), India, from April 1, 2020 to December 15, 2020. We studied 15 patients, of which 13 were treated at our hospital and two were treated in OPD. The median age of transplant recipients was 45 (Interquartile range [IQR]: 26–62) years, the majority being males, and recipients presented at a median of 4 (IQR: 0.3–11) years after transplant. The most common comorbidities included hypertension in 14 (94%) and diabetes 3 (20%) patients. The presenting symptoms at presentation were cough (80%), headache (52%), fever (46%), and breathlessness (26%). Clinical severity as per computerized tomography (CT) severity score ranged from mild (20%), moderate (53%), and severe (27%). Strategies to modify immunosuppressants included discontinuation of antimetabolites without changes in calcineurin inhibitors and steroids (100%). Antiviral therapy (Favipiravir and Remdesivir) was associated with better outcomes and reduced hospital stay. Risk factors for mortality included ABO-incompatibility, severity of disease, high Coronavirus Disease 2019 (COVID-19) Reporting and Data System (CO-RADS) score, allograft dysfunction before COVID-19 infection, acute kidney injury, elevated inflammatory markers, and intensive care unit/ventilator requirement. Overall patient mortality was 13.2%. Risk factor for mortality in COVID-19 positive with RTR appears to be ABO-incompatible transplant, having a previous history of rejection, and patient requiring ventilatory support

    A PROSPECTIVE OBSERVATIONAL STUDY ON PREVALENCE OF HYPOTHYROIDISM IN A TERTIARY CARE TEACHING HOSPITAL

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    Objective: To determine the prevalence of hypothyroidism in a rural population of Nandyal.Methods: A prospective study was conducted in Santhiram medical college and general hospital, Nandyal from July 2017 to December 2017, to study the prevalence of hypothyroidism among the population. Results: In this study, 1000 patients were evaluated for the thyroid functioning, among them n=104(10.4%) showing positive results in hypothyroidism. The positive 104 patients showed that n=63 (60.57%) of the population are in the age limit of 21-40. Out of the same population are n=11 (10.6%) are male and female are n=93 (89.43%). In age group distribution more prevalence was observed in 21-30 y of age group n=36 (34.61%). In this study, sub-clinical hypothyroidism was prevalent in females n=80 (76.92%) than males n=10 (9.61%).Conclusion: Our study demonstrates that hypothyroidism was higher in a female with age group as 21-40 y and there is a significant prevalence of hypothyroidism in the study population

    Planar SOFC system modelling and simulation including a 3D stack module

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    A solid oxide fuel cell (SOFC) system consists of a fuel cell stack with its auxiliary components. Modelling an entire SOFC system can be simplified by employing standard process flowsheeting software. However, no in-built SOFC module exists within any of the commercial flowsheet simulators. In Amiri et al. (Comput. Chem. Eng., 2015, 78:10-23), a rigorous SOFC module was developed to fill this gap. That work outlined a multi-scale approach to SOFC modelling and presented analyses at compartment, channel and cell scales. The current work extends the approach to stack and system scales. Two case studies were conducted on a simulated multilayer, planar SOFC stack with its balance of plant (BoP) components. Firstly, the effect of flow maldistribution in the stack manifold on the SOFC's internal variables was examined. Secondly, the interaction between the stack and the BoP was investigated through the effect of recycling depleted fuel. The results showed that anode gas recycling could be used for managing the gradients within the stack, while also improving fuel utilisation and water management

    On q-series and continued fractions

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    In this paper we have established interesting results involving continued fraction. Special cases of the result established herein have also been discussed

    RNF166 Determines Recruitment of Adaptor Proteins during Antibacterial Autophagy

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    Xenophagy is a form of selective autophagy that involves the targeting and elimination of intracellular pathogens through several recognition, recruitment, and ubiquitination events. E3 ubiquitin ligases control substrate selectivity in the ubiquitination cascade; however, systematic approaches to map the role of E3 ligases in antibacterial autophagy have been lacking. We screened more than 600 putative human E3 ligases, identifying E3 ligases that are required for adaptor protein recruitment and LC3-bacteria colocalization, critical steps in antibacterial autophagy. An unbiased informatics approach pinpointed RNF166 as a key gene that interacts with the autophagy network and controls the recruitment of ubiquitin as well as the autophagy adaptors p62 and NDP52 to bacteria. Mechanistic studies demonstrated that RNF166 catalyzes K29- and K33-linked polyubiquitination of p62 at residues K91 and K189. Thus, our study expands the catalog of E3 ligases that mediate antibacterial autophagy and identifies a critical role for RNF166 in this process.Leona M. and Harry B. Helmsley Charitable Trust (2014PG-IBD016)National Institutes of Health (U.S.) (R01DK097485)National Institutes of Health (U.S.) (U19AI109725)National Institutes of Health (U.S.) (P30DK043351

    Entropy of near-extremal black holes in AdS_5

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    We construct the microstates of near-extremal black holes in AdS_5 x S^5 as gases of defects distributed in heavy BPS operators in the dual SU(N) Yang-Mills theory. These defects describe open strings on spherical D3-branes in the S^5, and we show that they dominate the entropy by directly enumerating them and comparing the results with a partition sum calculation. We display new decoupling limits in which the field theory of the lightest open strings on the D-branes becomes dual to a near-horizon region of the black hole geometry. In the single-charge black hole we find evidence for an infrared duality between SU(N) Yang-Mills theories that exchanges the rank of the gauge group with an R-charge. In the two-charge case (where pairs of branes intersect on a line), the decoupled geometry includes an AdS_3 factor with a two-dimensional CFT dual. The degeneracy in this CFT accounts for the black hole entropy. In the three-charge case (where triples of branes intersect at a point), the decoupled geometry contains an AdS_2 factor. Below a certain critical mass, the two-charge system displays solutions with naked timelike singularities even though they do not violate a BPS bound. We suggest a string theoretic resolution of these singularities.Comment: LaTeX; v2: references and a few additional comments adde
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