1,146 research outputs found

    Gauge invariant perturbation theory and non-critical string models of Yang-Mills theories

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    We carry out a gauge invariant analysis of certain perturbations of D2D-2-branes solutions of low energy string theories. We get generically a system of second order coupled differential equations, and show that only in very particular cases it is possible to reduce it to just one differential equation. Later, we apply it to a multi-parameter, generically singular family of constant dilaton solutions of non-critical string theories in DD dimensions, a generalization of that recently found in arXiv:0709.0471[hep-th]. According to arguments coming from the holographic gauge theory-gravity correspondence, and at least in some region of the parameters space, we obtain glue-ball spectra of Yang-Mills theories in diverse dimensions, putting special emphasis in the scalar metric perturbations not considered previously in the literature in the non critical setup. We compare our numerical results to those studied previously and to lattice results, finding qualitative and in some cases, tuning properly the parameters, quantitative agreement. These results seem to show some kind of universality of the models, as well as an irrelevance of the singular character of the solutions. We also develop the analysis for the T-dual, non trivial dilaton family of solutions, showing perfect agreement between them.Comment: A new reference added

    A gentle introduction to the functional renormalization group: the Kondo effect in quantum dots

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    The functional renormalization group provides an efficient description of the interplay and competition of correlations on different energy scales in interacting Fermi systems. An exact hierarchy of flow equations yields the gradual evolution from a microscopic model Hamiltonian to the effective action as a function of a continuously decreasing energy cutoff. Practical implementations rely on suitable truncations of the hierarchy, which capture nonuniversal properties at higher energy scales in addition to the universal low-energy asymptotics. As a specific example we study transport properties through a single-level quantum dot coupled to Fermi liquid leads. In particular, we focus on the temperature T=0 gate voltage dependence of the linear conductance. A comparison with exact results shows that the functional renormalization group approach captures the broad resonance plateau as well as the emergence of the Kondo scale. It can be easily extended to more complex setups of quantum dots.Comment: contribution to Les Houches proceedings 2006, Springer styl

    A slice of AdS_5 as the large N limit of Seiberg duality

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    A slice of AdS_5 is used to provide a 5D gravitational description of 4D strongly-coupled Seiberg dual gauge theories. An (electric) SU(N) gauge theory in the conformal window at large N is described by the 5D bulk, while its weakly coupled (magnetic) dual is confined to the IR brane. This framework can be used to construct an N = 1 MSSM on the IR brane, reminiscent of the original Randall-Sundrum model. In addition, we use our framework to study strongly-coupled scenarios of supersymmetry breaking mediated by gauge forces. This leads to a unified scenario that connects the extra-ordinary gauge mediation limit to the gaugino mediation limit in warped space.Comment: 47 Pages, axodraw4j.st

    Upper gastrointestinal Crohn's disease

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    Symptomatic gastroduodenal manifestations of Crohn's disease are rare, with less than 4% of patients being clinically symptomatic. Gastroduodenal involvement may, however, be found endoscopically in 20% and in up to 40% of cases histologically, most frequently as Helicobacter pylori-negative focal gastritis, usually in patients with concomitant distal ileal disease. In practice, the activity of concomitant distal Crohn's disease usually determines the indication for therapy, except in the presence of obstructive gastroduodenal symptoms. With the few data available, it seems correct to say that localized gastroduodenal disease should be treated with standard medical therapy used for more distal disease, with the exception of the galenic formulation of sulfasalazine and mesalazine with pH-dependent release. The presence of symptoms of obstruction needs aggressive therapy. If medical therapy with steroids and immunomodulatory drugs does not alleviate the symptoms, balloon dilation and surgery are the options to consider. [Ed.]]]> oai:serval.unil.ch:BIB_5E8B8CEC2A7F 2022-05-07T01:18:50Z openaire documents urnserval <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_5E8B8CEC2A7F Agniṣṭoma and the nature of sacrifice Bronkhorst, Johannes info:eu-repo/semantics/bookPart incollection 2016 On Meaning and Mantras: Essays in Honor of Frits Staal, pp. 79-99 Thompson, George (ed.) Payne, Richard K. (ed.) info:eu-repo/semantics/altIdentifier/isbn/978-1-886439-64-1 eng https://serval.unil.ch/resource/serval:BIB_5E8B8CEC2A7F.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_5E8B8CEC2A7F4 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_5E8B8CEC2A7F4 info:eu-repo/semantics/publishedVersion info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_5E8C17A3E220 2022-05-07T01:18:50Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_5E8C17A3E220 Selective regulation of acid-sensing ion channel 1 by serine proteases. info:doi:10.1074/jbc.M407381200 info:eu-repo/semantics/altIdentifier/doi/10.1074/jbc.M407381200 info:eu-repo/semantics/altIdentifier/pmid/15247234 Poirot, O. Vukicevic, M. Boesch, A. Kellenberger, S. info:eu-repo/semantics/article article 2004 Journal of Biological Chemistry, vol. 279, no. 37, pp. 38448-38457 info:eu-repo/semantics/altIdentifier/pissn/0021-9258[print], 0021-9258[linking] <![CDATA[Acid-sensing ion channels (ASICs) are neuronal Na(+) channels that belong to the epithelial Na(+) channel/degenerin family. ASICs are transiently activated by a rapid drop in extracellular pH. Conditions of low extracellular pH, such as ischemia and inflammation in which ASICs are thought to be active, are accompanied by increased protease activity. We show here that serine proteases modulate the function of ASIC1a and ASIC1b but not of ASIC2a and ASIC3. We show that protease exposure shifts the pH dependence of ASIC1a activation and steady-state inactivation to more acidic pH. As a consequence, protease exposure leads to a decrease in current response if ASIC1a is activated by a pH drop from pH 7.4. If, however, acidification occurs from a basal pH of approximately 7, protease-exposed ASIC1a shows higher activity than untreated ASIC1a. We provide evidence that this bi-directional regulation of ASIC1a function also occurs in neurons. Thus, we have identified a mechanism that modulates ASIC function and may allow ASIC1a to adapt its gating to situations of persistent extracellular acidification

    Production of volatile fatty acids from slaughterhouse blood by mixed-culture fermentation

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    The volatile fatty acids (VFA) production potential from animal blood and the factors affecting this process were investigated in this study. In order to simulate an industrial process different operation modes, batch, fed batch and semi-continuous, were also evaluated. Due to high ammonia concentration in fermentation broth, VFA concentration up to 100 g L-1 was achieved without addition of buffer and methanogen inhibitor. In general, acetic, n-butyric and iso-valeric acids were the most predominant species, although different operational conditions affected the VFA concentration, profile, production rate and yield. The microbial community analysis was conducted on the reactors with the best performance, revealing that 70-90% of the microbial population was from the Clostridiales order with a strong presence from the Sporanaerobacter genus. These results demonstrated the feasibility of a VFA-platform bio-refinery using high-protein wastes as substrate via mixed-culture fermentation under non-sterilised conditions

    Social sciences research in neglected tropical diseases 2: A bibliographic analysis

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    The official published version of the article can be found at the link below.Background There are strong arguments for social science and interdisciplinary research in the neglected tropical diseases. These diseases represent a rich and dynamic interplay between vector, host, and pathogen which occurs within social, physical and biological contexts. The overwhelming sense, however, is that neglected tropical diseases research is a biomedical endeavour largely excluding the social sciences. The purpose of this review is to provide a baseline for discussing the quantum and nature of the science that is being conducted, and the extent to which the social sciences are a part of that. Methods A bibliographic analysis was conducted of neglected tropical diseases related research papers published over the past 10 years in biomedical and social sciences. The analysis had textual and bibliometric facets, and focussed on chikungunya, dengue, visceral leishmaniasis, and onchocerciasis. Results There is substantial variation in the number of publications associated with each disease. The proportion of the research that is social science based appears remarkably consistent (<4%). A textual analysis, however, reveals a degree of misclassification by the abstracting service where a surprising proportion of the "social sciences" research was pure clinical research. Much of the social sciences research also tends to be "hand maiden" research focused on the implementation of biomedical solutions. Conclusion There is little evidence that scientists pay any attention to the complex social, cultural, biological, and environmental dynamic involved in human pathogenesis. There is little investigator driven social science and a poor presence of interdisciplinary science. The research needs more sophisticated funders and priority setters who are not beguiled by uncritical biomedical promises

    Plant cell culture technology in the cosmetics and food industries : current state and future trends

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    The production of drugs, cosmetics, and food which are derived from plant cell and tissue cultures has a long tradition. The emerging trend of manufacturing cosmetics and food products in a natural and sustainable manner has brought a new wave in plant cell culture technology over the past 10 years. More than 50 products based on extracts from plant cell cultures have made their way into the cosmetics industry during this time, whereby the majority is produced with plant cell suspension cultures. In addition, the first plant cell culture-based food supplement ingredients, such as Echigena Plus and Teoside 10, are now produced at production scale. In this mini review, we discuss the reasons for and the characteristics as well as the challenges of plant cell culture-based productions for the cosmetics and food industries. It focuses on the current state of the art in this field. In addition, two examples of the latest developments in plant cell culture-based food production are presented, that is, superfood which boosts health and food that can be produced in the lab or at home

    Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

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    Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

    The unfolded protein response in immunity and inflammation.

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    The unfolded protein response (UPR) is a highly conserved pathway that allows the cell to manage endoplasmic reticulum (ER) stress that is imposed by the secretory demands associated with environmental forces. In this role, the UPR has increasingly been shown to have crucial functions in immunity and inflammation. In this Review, we discuss the importance of the UPR in the development, differentiation, function and survival of immune cells in meeting the needs of an immune response. In addition, we review current insights into how the UPR is involved in complex chronic inflammatory diseases and, through its role in immune regulation, antitumour responses.This work was supported by the Netherlands Organization for Scientific Research Rubicon grant 825.13.012 (J.G.); US National Institutes of Health (NIH) grants DK044319, DK051362, DK053056 and DK088199, and the Harvard Digestive Diseases Center (HDDC) grant DK034854 (R.S.B.); National Institutes of Health grants DK042394, DK088227, DK103183 and CA128814 (R.J.K.); and European Research Council (ERC) Starting Grant 260961, ERC Consolidator Grant 648889, and the Wellcome Trust Investigator award 106260/Z/14/Z (A.K.).This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nri.2016.6
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