2,384 research outputs found

    Limit on the tau neutrino mass from the ALEPH experiment

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    WLCG Input to Pisa workshop on Resilience-Explicit Computing in Grids

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    This document summarizes the input from the Worldwide LHC Computing Grid (WLCG) to the workshop held on Resilience-Explicit Computing in Grids in Pisa, July 14th 2008. The techniques on which WLCG services have been built have been described in numerous papers, including [1][2][3]. They are based on many years of experience in delivering reliable services, using knowledge gained from the LEP era and from other High Energy Physics experiments around the world

    POOL File Catalog, Collection and Metadata Components

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    The POOL project is the common persistency framework for the LHC experiments to store petabytes of experiment data and metadata in a distributed and grid enabled way. POOL is a hybrid event store consisting of a data streaming layer and a relational layer. This paper describes the design of file catalog, collection and metadata components which are not part of the data streaming layer of POOL and outlines how POOL aims to provide transparent and efficient data access for a wide range of environments and use cases - ranging from a large production site down to a single disconnected laptops. The file catalog is the central POOL component translating logical data references to physical data files in a grid environment. POOL collections with their associated metadata provide an abstract way of accessing experiment data via their logical grouping into sets of related data objects.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, 1 eps figure, PSN MOKT00

    Circunstancias ambientales que pueden haber influido en la pandemia por COVID-19

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    La pandemia por COVID-19 ha desatado un estremecimiento en las bases sociales en todos los países del mundo, con unas circunstancias que tendrán implicaciones sanitarias, culturales, económicas y sociales que marcarán el inicio del siglo XXI. Para conocer los eventos que desencadenaron esta epidemia, podemos analizar a través de una serie de preguntas cuáles fueron los hechos objetivos que marcaron su inicio; al mirar en retrospectiva estos hechos podríamos tener una luz sobre cómo prevenir eventos de esta índole en el futuro. ¿Cuáles fueron las circunstancias que desencadenaron la pandemia? ¿Fue una serie de transmisiones zoonóticas que produjeron la infección en los humanos? ¿El ambiente ha tenido algo que ver? El desafio de las grandes potencias mundiales para mantener la hegemonía dará curso a una plétora de investigaciones acerca de la biología del virus, las variables epidemiológicas, posibles vacunas y las formas de prevención de los desenlaces fatales en las personas con enfermedades crónicas de riesgo cardiovascular. En el presente manuscrito se pretende analizar algunos de estos cuestionamientos

    Implications of the ALEPH tau-Lepton Decay Data for Perturbative and Non-Perturbative QCD

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    We use ALEPH data on hadronic τ\tau decays in order to calculate Euclidean coordinate space correlation functions in the vector and axial-vector channels. The linear combination VAV-A receives no perturbative contribution and is quantitatively reproduced by the instanton liquid model. In the case of V+AV+A the instanton calculation is in good agreement with the data once perturbative corrections are included. These corrections clearly show the evolution of αs\alpha_s. We also analyze the range of validity of the Operator Product Expansion (OPE). In the VAV-A channel we find a dimension d=6d=6 contribution which is comparable to the original SVZ estimate, but the instanton model provides a different non-singular term of the same magnitude. In the V+AV+A case both the OPE and the instanton model predict the same d=4d=4 power correction induced by the gluon condensate, but it is masked by much larger perturbative contributions. We conclude that the range of validity of the OPE is limited to x\lsim0.3 fm, whereas the instanton model describes the data over the entire range.Comment: 4 pages, 6 figure

    IL-1 and senescence: Friends and foe of EGFR neutralization and immunotherapy

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    Historically, senescence has been considered a safe program in response to multiple stresses in which cells undergo irreversible growth arrest. This process is characterized by morphological and metabolic changes, heterochromatin formation, and secretion of inflammatory components, known as senescence-associated secretory phenotype (SASP). However, recent reports demonstrated that anti-cancer therapy itself can stimulate a senescence response in tumor cells, the so-called therapy-induced senescence (TIS), which may represent a temporary bypass pathway that promotes drug resistance. In this context, several studies have shown that EGFR blockage, by TKIs or moAbs, promotes TIS by increasing IL-1 cytokine production, thus pushing cells into a "pseudo-senescent" state. Today, senotherapeutic agents are emerging as a potential strategy in cancer treatment thanks to their dual role in annihilating senescent cells and simultaneously preventing their awakening into a resistant and aggressive form. Here, we summarize classic and recent findings about the cellular processes driving senescence and SASP, and we provide a state-of-the-art of the anti-cancer strategies available so far that exploits the activation and/or blockade of senescence-based mechanisms

    Test of the Running of αs\alpha_s in τ\tau Decays

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    The τ\tau decay rate into hadrons of invariant mass smaller than s0ΛQCD\sqrt{s_0}\gg\Lambda_{\rm QCD} can be calculated in QCD assuming global quark--hadron duality. It is shown that this assumption holds for s0>0.7s_0>0.7~GeV2^2. From measurements of the hadronic mass distribution, the running coupling constant αs(s0)\alpha_s(s_0) is extracted in the range 0.7~GeV2<s0<mτ2^2<s_0<m_\tau^2. At s0=mτ2s_0=m_\tau^2, the result is αs(mτ2)=0.329±0.030\alpha_s(m_\tau^2)=0.329\pm 0.030. The running of αs\alpha_s is in good agreement with the QCD prediction.Comment: 9 pages, 3 figures appended; shortened version with new figures, to appear in Physical Review Letters (April 1996

    Climate variability during MIS 20–18 as recorded by alkenone-SST and calcareous plankton in the Ionian Basin (central Mediterranean)

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    This study shows the first Mediterranean high-resolution record of alkenone-derived sea surface temperature (SST) in the marine sediments outcropping at the Ideale section (IS) (southern Italy, central Mediterranean) from late marine isotope stage (MIS) 20 - through early MIS 18. The SST pattern evidences glacial-interglacial up to submillennial-scale temperature variation, with lower values (~13 °C) in late MIS 20 and substage 19b, and higher values (up to 21 °C) in MIS 19c and in the interstadials of MIS 19a. The SST data are combined with the new calcareous plankton analysis and the available, chronologically well-constrained carbon and oxygen isotope records in the IS. The multi-proxy approach, together with the location of the IS near the Italian coasts, the lower circalittoral-upper bathyal depositional setting, and high sedimentation rate allow to document long-and short-term paleoenvironmental modifications (sea level, rainfall, inorganic/organic/fresh water input to the basin), as a response to regional and global climate changes. The combined proxies reveal the occurrence of a terminal stadial event in late MIS 20 (here Med-HTIX), and warm-cold episodes (here Med-BATIX and Med-YDTIX) during Termination IX (TIX), which recall those that occurred through the last termination (TI). During these periods and the following ghost sapropel layer (insolation cycle 74, 784 ka) in the early MIS 19, high frequency internal changes are synchronously recorded by all proxies. The substage MIS 19c is warm but quite unstable, with several episodes of paleoenvironmental changes, associated with fluctuating tropical-subtropical water inflow through the Gibraltar Strait, variations of the cyclonic regime in the Ionian basin, and the southward shift of westerly winds and winter precipitation over southern Europe and Mediterranean basin. Three high-amplitude millennial-scale oscillations in the patterns of SST and calcareous plankton key taxa during MIS 19a are interpreted as linked to changes in temperature as well as in salinity due to periodical water column stratification and mixing. The main processes involved in the climate variability include changes in oceanographic exchanges through the Gibraltar Strait during modulations of Atlantic meridional overturning circulation and/or variations in atmospheric dynamics related to the influence of westerly and polar winds acting in the paleo-Ionian basin. A strong climate teleconnection between the North Atlantic and Mediterranean is discussed, and a prominent role of atmospheric processes in the central Mediterranean is evidenced by comparing data sets at the IS with Italian and extra-Mediterranean marine and terrestrial records

    Testing QCD with Hypothetical Tau Leptons

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    We construct new tests of perturbative QCD by considering a hypothetical tau lepton of arbitrary mass, which decays hadronically through the electromagnetic current. We can explicitly compute its hadronic width ratio directly as an integral over the e^+ e^- annihilation cross section ratio, R_{e^+e^-}. Furthermore, we can design a set of commensurate scale relations and perturbative QCD tests by varying the weight function away from the form associated with the V-A decay of the physical tau. This method allows the wide range of the R_{e^+e^-} data to be used as a probe of perturbative QCD.Comment: 4 pages, 4 figure
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