1,330 research outputs found

    Holographic Anomalous Conductivities and the Chiral Magnetic Effect

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    We calculate anomaly induced conductivities from a holographic gauge theory model using Kubo formulas, making a clear conceptual distinction between thermodynamic state variables such as chemical potentials and external background fields. This allows us to pinpoint ambiguities in previous holographic calculations of the chiral magnetic conductivity. We also calculate the corresponding anomalous current three-point functions in special kinematic regimes. We compare the holographic results to weak coupling calculations using both dimensional regularization and cutoff regularization. In order to reproduce the weak coupling results it is necessary to allow for singular holographic gauge field configurations when a chiral chemical potential is introduced for a chiral charge defined through a gauge invariant but non-conserved chiral density. We argue that this is appropriate for actually addressing charge separation due to the chiral magnetic effect.Comment: 17 pages, 1 figure. v2: 18 pages, 1 figure, discussion clarified throughout the text, references added, version accepted for publication in JHE

    Two highly divergent alcohol dehydrogenases of melon exhibit fruit ripening-specific expression and distinct biochemical characteristics

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    Alcohol dehydrogenases (ADH) participate in the biosynthetic pathway of aroma volatiles in fruit by interconverting aldehydes to alcohols and providing substrates for the formation of esters. Two highly divergent ADH genes (15% identity at the amino acid level) of Cantaloupe Charentais melon (Cucumis melo var. Cantalupensis) have been isolated. Cm-ADH1 belongs to the medium-chain zinc-binding type of ADHs and is highly similar to all ADH genes expressed in fruit isolated so far. Cm-ADH2 belongs to the short-chain type of ADHs. The two encoded proteins are enzymatically active upon expression in yeast. Cm-ADH1 has strong preference for NAPDH as a co-factor, whereas Cm-ADH2 preferentially uses NADH. Both Cm-ADH proteins are much more active as reductases with Kms 10–20 times lower for the conversion of aldehydes to alcohols than for the dehydrogenation of alcohols to aldehydes. They both show strong preference for aliphatic aldehydes but Cm-ADH1 is capable of reducing branched aldehydes such as 3-methylbutyraldehyde, whereas Cm-ADH2 cannot. Both Cm-ADH genes are expressed specifically in fruit and up-regulated during ripening. Gene expression as well as total ADH activity are strongly inhibited in antisense ACC oxidase melons and in melon fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. These data suggest that each of the Cm-ADH protein plays a specific role in the regulation of aroma biosynthesis in melon fruit

    Institutions, Human Capital, and Development

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    In this article, we revisit the relationship among institutions, human capital, and development. We argue that empirical models that treat institutions and human capital as exogenous are misspecified, both because of the usual omitted variable bias problems and because of differential measurement error in these variables, and that this misspecification is at the root of the very large returns of human capital, about four to five times greater than that implied by micro (Mincerian) estimates, found in the previous literature. Using cross-country and cross-regional regressions, we show that when we focus on historically determined differences in human capital and control for the effect of institutions, the impact of institutions on long-run development is robust, whereas the estimates of the effect of human capital are much diminished and become consistent with micro estimates. Using historical and cross-country regression evidence, we also show that there is no support for the view that differences in the human capital endowments of early European colonists have been a major factor in the subsequent institutional development of former colonies.Comisión Nacional de Investigación Ciencia y Tecnología (Chile) (CONICYT/Programa de Investigación Asociativa (project SOC1102))United States. Army Research Office (ARO MURI W911NF-12-1-0509

    The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?

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    The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework

    A Fuzzy Inference System for Closed-Loop Deep Brain Stimulation in Parkinson’s Disease

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    Parkinsons disease is a complex neurodegenerative disorder for which patients present many symptoms, tremor being the main one. In advanced stages of the disease, Deep Brain Stimulation is a generalized therapy which can significantly improve the motor symptoms. However despite its beneficial effects on treating the symptomatology, the technique can be improved. One of its main limitations is that the parameters are fixed, and the stimulation is provided uninterruptedly, not taking into account any fluctuation in the patients state. A closed-loop system which provides stimulation by demand would adjust the stimulation to the variations in the state of the patient, stimulating only when it is necessary. It would not only perform a more intelligent stimulation, capable of adapting to the changes in real time, but also extending the devices battery life, thereby avoiding surgical interventions. In this work we design a tool that learns to recognize the principal symptom of Parkinsons disease and particularly the tremor. The goal of the designed system is to detect the moments the patient is suffering from a tremor episode and consequently to decide whether stimulation is needed or not. For that, local field potentials were recorded in the subthalamic nucleus of ten Parkinsonian patients, who were diagnosed with tremor-dominant Parkinsons disease and who underwent surgery for the implantation of a neurostimulator. Electromyographic activity in the forearm was simultaneously recorded, and the relation between both signals was evaluated using two different synchronization measures. The results of evaluating the synchronization indexes on each moment represent the inputs to the designed system. Finally, a fuzzy inference system was applied with the goal of identifying tremor episodes. Results are favourable, reaching accuracies of higher 98.7 % in 70 % of the patients.Centro de Investigación Biomédica en RedDepto. de Psicología Experimental, Procesos Cognitivos y LogopediaDepto. de Radiología, Rehabilitación y FisioterapiaFac. de PsicologíaFac. de MedicinaTRUEpu

    Classificação do atendimento pré-hospitalar pediátrico como instrumento para otimizar a alocação de recursos no atendimento do trauma na cidade de São Paulo, Brasil

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    PURPOSE: To evaluate the pediatric prehospital care in São Paulo, the databases from basic life support units (BLSU) and ALSU, and to propose a simple and effective method for evaluating trauma severity in children at the prehospital phase. METHODS: A single firemen headquarter coordinates all prehospital trauma care in São Paulo city. Two databases were analyzed for children from 0 to 18 years old between 1998 and 2001: one from the Basic Life Support Units (BLSU - firemen) and one from the Advanced Life Support Units (ALSU - doctor and firemen). During this period, advanced life support units provided medical reports from 604 victims, while firemen provided 12.761 reports (BLSU+ALSU). Pre-Hospital Pediatric Trauma Classification is based on physiological status, trauma mechanism and anatomic injuries suggesting high energy transfer. In order to evaluate the proposed classification, it was compared to the Glasgow Coma Score and to the Revised Trauma Score. RESULTS: There was a male predominance in both databases and the most common trauma mechanism was transport related, followed by falls. Mortality was 1.6% in basic life support units and 9.6% in ALSU. There was association among the proposed score, the Glasgow Coma Score and to the Revised Trauma Score (p<0.0001). CONCLUSION: Pre-Hospital Pediatric Trauma Classification is a simple and reliable method for assessment, triage and recruitment of pediatric trauma resources.OBJETIVO: Avaliar o atendimento pré-hospitalar de crianças e adolescentes em São Paulo, avaliar o banco de dados das Unidades de Suporte Básico (UR) e Avançado (USA) e propor um método simples e eficaz para a avaliação da gravidade do trauma pediátrico na fase pré-hospitalar. MÉTODOS: Uma única central do Corpo de Bombeiros (COBOM) coordena todo o atendimento pré-hospitalar em São Paulo. Dois bancos de dados foram analisados para crianças de 0 a 18 anos de idade, entre 1998 e 2001: um das Unidades de Suporte Básico de Vida (UR- bombeiros) e outra de Unidades de Suporte Avançado (USA - médico e bombeiros). Neste período, o Serviço de Atendimento Médico de Urgência do Estado de São Paulo (SAMU) forneceu relatórios médicos de 604 vítimas, enquanto os bombeiros forneceram relatórios de 12.761 vitimas (UR+USA). A classificação do trauma pré-hospitalar pediátrico é baseada na condição fisiológica, mecanismo de trauma e lesões anatômicas das vítimas. A classificação do trauma pré-hospitalar pediátrico foi comparada à Escala de Coma de Glasgow (GCS) e ao Escore de Trauma Revisado (RTS). RESULTADOS: Houve predominância do sexo masculino em ambos bancos de dados. O mecanismo de trauma mais freqüente foi relacionado a transporte, seguido de quedas. A mortalidade foi 1,6% nas Unidades Básicas e 9,6% no Suporte Avançado. Houve associação entre a classificação do trauma pré-hospitalar pediátrico, Escala de Coma de Glasgow (GCS) e ao Escore de Trauma Revisado (RTS) GCS e RTS (p<0,0001). CONCLUSÃO: A classificação do trauma pré-hospitalar pediátrico é um método simples e confiável para a avaliação, triagem e recrutamento de recursos para o atendimento pré-hospitalar do trauma pediátrico.Universidade Federal de São Paulo (UNIFESP) Department of SurgeryUNIFESP, Department of SurgerySciEL

    Influence of GB virus C on IFN-γ and IL-2 production and CD38 expression in T lymphocytes from chronically HIV-infected and HIV-HCV-co-infected patients

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    This study was designed to assess the effect of GB virus (GBV)-C on the immune response to human immunodeficiency virus (HIV) in chronically HIV-infected and HIV- hepatitis C virus (HCV)-co-infected patients undergoing antiretroviral therapy. A cohort of 159 HIV-seropositive patients, of whom 52 were HCV-co-infected, was included. Epidemiological data were collected and virological and immunological markers, including the production of interferon gamma (IFN-γ) and interleukin (IL)-2 by CD4, CD8 and Tγδ cells and the expression of the activation marker, CD38, were assessed. A total of 65 patients (40.8%) presented markers of GBV-C infection. The presence of GBV-C did not influence HIV and HCV replication or TCD4 and TCD8 cell counts. Immune responses, defined by IFN-γ and IL-2 production and CD38 expression did not differ among the groups. Our results suggest that neither GBV-C viremia nor the presence of E2 antibodies influence HIV and HCV viral replication or CD4 T cell counts in chronically infected patients. Furthermore, GBV-C did not influence cytokine production or CD38-driven immune activation among these patients. Although our results do not exclude a protective effect of GBV-C in early HIV disease, they demonstrate that this effect may not be present in chronically infected patients, who represent the majority of patients in outpatient clinics.Universidade Federal de São Paulo (UNIFESP) Laboratório de Virologia e Imunologia Disciplina de InfectologiaFleury Medicina DiagnósticaUNIFESP, Laboratório de Virologia e Imunologia Disciplina de InfectologiaSciEL

    Evaluation of guidance provided by international standards on metrics and timelines for run-life estimation of oil and gas equipment

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    Run-life is a concept used in the oil and gas industry to express time to failure for running equipment. When estimating this as part of reliability engineering activities, different metrics and time periods are considered. One metric is the traditional ‘mean time to failure’ (MTTF), but alternatives such as ‘average run-time’ or ‘average run-life’ can also be considered. For calculating these metrics, different time periods can be used. For example, when estimating the MTTF of well completion equipment, operating times or running times are normally used. However, the periods can also include idle time, where the item is technically available, but associated parts of the production facility might not be. For consistency across the industry, on how to interpret the metrics and what to include in calculating them when performing estimations, ISO 14224 (2016) and IEC 60050-192 (2015) in tandem provide guidance to ensure quality in reliability data collection and analysis. While MTTF is defined and a theoretical basis is given, guidance on when to use the different timelines for the estimation is sparse. Neither ‘run-time’ nor ‘run-life’ is explicitly defined in these standards. They provide no guidance on how to interpret and use the metrics ‘average run-time’ and ‘average run-life’, despite these sometimes replacing the MTTF in reliability analyses. In this article, we discuss the variation in metrics and associated timeline definitions. A main purpose is to identify improvement potentials in the international standards and suggest how to achieve appropriate guidance for consistent interpretation and use of time-to-failure metrics in the oil and gas industry. An additional purpose is to clarify whether all these metrics are really needed. There is particularly confusion around ‘run-time’, which some interpret as a reliability metric and some as an item’s cumulative running time. One suggestion is that the standards focus more on ‘running time’, by adding a formal definition, and clarify how it compares with operating time and run-time, and when to use it. We also suggest introducing ‘running time to failure’ and ‘operating time to failure’, which would be consistent with existing terminology, while clarifying the timeline being referred to. We use examples from well drilling and completion systems, to show the reliability implications for modeling and calculations.publishedVersio

    Challenges and recent progress in drug discovery for tropical diseases

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    Infectious tropical diseases have a huge effect in terms of mortality and morbidity, and impose a heavy economic burden on affected countries. These diseases predominantly affect the world’s poorest people. Currently available drugs are inadequate for the majority of these diseases, and there is an urgent need for new treatments. This Review discusses some of the challenges involved in developing new drugs to treat these diseases and highlights recent progress. While there have been notable successes, there is still a long way to go.</p

    Quality changes and shelf-life prediction of a fresh fruit and vegetables purple smoothie

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    The sensory, microbial and bioactive quality changes of untreated (CTRL) and mild heat−treated (HT; 90 ºC/45 s) smoothies were studied and modelled throughout storage (5, 15 and 25 ºC). The overall acceptability was better preserved in HT samples being highly correlated (hierarchical clustering) with the flavour. The sensory quality data estimated smoothie shelf−life (CTRL/HT) of 18/55 (at 5 ºC), 4.5/12 (at 15 ºC), 2.4/5.8 (at 25 ºC) days. The yeast and moulds growth rate was lower in HT compared to CTRL while a lag phase for mesophiles/psychrophiles was observed in HT−5/15 ºC. HT and 5 ºC−storage stabilized the phenolics content. FRAP reported the best correlation (R2=0.94) with the studied bioactive compounds, followed by ABTS (R2=0.81) while DPPH was the total antioxidant capacity method with the lowest adjustment (R2=0.49). Conclusively, modelling was used to estimate the shelf−life of a smoothie based on quality retention after a short time−high temperature heat treatment that better preserved microbial and nutritional quality during storage.The financial support of this research was provided by the Ministerio Español de Economía y Competitividad MINECO (Projects AGL2013−48830−C2−1−R and AGL2013−48993−C2−1−R) and by FEDER funds. G.A. González−Tejedor thanks to Panamá Government for the scholarship to carry out his PhD Thesis. A. Garre (BES−2014−070946) is grateful to the MINECO for awarding him a pre−doctoral grant. We are also grateful to E. Esposito and N. Castillejo for their skilful technical assistance
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