1,238 research outputs found
ATLAS IBL Pixel Upgrade
The upgrade for ATLAS detector will undergo different phase towards
super-LHC. The first upgrade for the Pixel detector will consist of the
construction of a new pixel layer which will be installed during the first
shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called
Insertable B-Layer (IBL), will be inserted between the existing pixel detector
and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will
require the development of several new technologies to cope with increase of
radiation or pixel occupancy and also to improve the physics performance which
will be achieved by reducing the pixel size and of the material budget. Three
different promising sensor technologies (planar-Si, 3D-Si and diamond) are
currently under investigation for the pixel detector. An overview of the
project with particular emphasis on pixel module is presented in this paper.Comment: 3 pages, 3 figures, presented at the 12th Topical Seminar on
Innovative Particle and Radiation Detectors (IPRD10) 7 - 10 June 2010, Siena
(IT). Accepted by Nuclear Physics B (Proceedings Supplements) (2011
Machine Learning-Based Elastic Cloud Resource Provisioning in the Solvency II Framework
The Solvency II Directive (Directive 2009/138/EC) is a European Directive issued in November 2009 and effective from January 2016, which has been enacted by the European Union to regulate the insurance and reinsurance sector through the discipline of risk management. Solvency II requires European insurance companies to conduct consistent evaluation and continuous monitoring of risks—a process which is computationally complex and extremely resource-intensive. To this end, companies are required to equip themselves with adequate IT infrastructures, facing a significant outlay.
In this paper we present the design and the development of a Machine Learning-based approach to transparently deploy on a cloud environment the most resource-intensive portion of the Solvency II-related computation. Our proposal targets DISAR®, a Solvency II-oriented system initially designed to work on a grid of conventional computers. We show how our solution allows to reduce the overall expenses associated with the computation, without hampering the privacy of the companies’ data (making it suitable for conventional public cloud environments), and allowing to meet the strict temporal requirements required by the Directive. Additionally, the system is organized as a self-optimizing loop, which allows to use information gathered from actual (useful) computations, thus requiring a shorter training phase. We present an experimental study conducted on Amazon EC2 to assess the validity and the efficiency of our proposal
Atrophy, oxidative switching and ultrastructural defects in skeletal muscle of the ataxia telangiectasia mouse model
Ataxia telangiectasia is a rare, multi system disease caused by ATM kinase deficiency. Atm-knockout mice recapitulate premature aging, immunodeficiency, cancer predisposition, growth retardation and motor defects, but not cerebellar neurodegeneration and ataxia. We explored whether Atm loss is responsible for skeletal muscle defects by investigating myofiber morphology, oxidative/glycolytic activity, myocyte ultrastructural architecture and neuromuscular junctions. Atm-knockout mice showed reduced muscle and fiber size. Atrophy, protein synthesis impairment and a switch from glycolytic to oxidative fibers were detected, along with an increase of in expression of slow and fast myosin types (Myh7, and Myh2 and Myh4, respectively) in tibialis anterior and solei muscles isolated from Atm-knockout mice. Transmission electron microscopy of tibialis anterior revealed misalignments of Z-lines and sarcomeres and mitochondria abnormalities that were associated with an increase in reactive oxygen species. Moreover, neuromuscular junctions appeared larger and more complex than those in Atm wild-type mice, but with preserved presynaptic terminals. In conclusion, we report for the first time that Atm-knockout mice have clear morphological skeletal muscle defects that will be relevant for the investigation of the oxidative stress response, motor alteration and the interplay with peripheral nervous system in ataxia telangiectasia
Variability and spectral energy distributions of low-luminosity active galactic nuclei: a simultaneous X-ray/UV look with Swift
We have observed four low-luminosity active galactic nuclei classified as
Type 1 LINERs with the X-ray Telescope (XRT) and the UltraViolet-Optical
Telescope (UVOT) onboard Swift, in an attempt to clarify the main powering
mechanism of this class of nearby sources. Among our targets, we detect X-ray
variability in NGC 3998 for the first time. The light curves of this object
reveal variations of up to 30% amplitude in half a day, with no significant
spectral variability on this time scale. We also observe a decrease of ~30%
over 9 days, with significant spectral softening. Moreover, the X-ray flux is
~40% lower than observed in previous years. Variability is detected in M 81 as
well, at levels comparable to those reported previously: a flux increase in the
hard X-rays (1-10 keV) of 30% in ~3 hours and variations by up to a factor of 2
within a few years. This X-ray behaviour is similar to that of
higher-luminosity, Seyfert-type, objects. Using previous
high-angular-resolution imaging data from the Hubble Space Telescope (HST), we
evaluate the diffuse UV emission due to the host galaxy and isolate the nuclear
flux in our UVOT observations. All sources are detected in the UV band, at
levels similar to those of the previous observations with HST. The XRT (0.2-10
keV) spectra are well described by single power-laws and the UV-to-X-ray flux
ratios are again consistent with those of Seyferts and radio-loud AGNs of
higher luminosity. The similarity in X-ray variability and broad-band energy
distributions suggests the presence of similar accretion and radiation
processes in low- and high-luminosity AGNs.Comment: 12 pages, 6 figures, in press in MNRA
The Ngillatun ritual: an anthropological analysis in cosmopolitical key from the Mapuche ontology.
A lo largo de los siglos los rituales indígenas han sido interpretados y observados desde múltiples perspectivas, muchas de ellas supeditadas a una visión etnocéntrica que ha sido fruto de las relaciones de poder asimétrico, en ocasiones invisibles, que la colonialidad ha acarreado a lo largo de los años y que concebían a esa alteridad como un simple “objeto de estudio”.
El presente trabajo a partir de la aplicación de la propuesta cosmopolítica pretende superar esa visión antropocéntrica que asumimos sobre el mundo y la naturaleza que nos rodea, aquí naturaleza y cultura pierden los significados aprendidos y socializados desde Occidente. De esta forma el trabajo aborda la perspectiva cosmopolítica del Ngillatun, ritual mapuche, como una herramienta para subvertir el orden político moderno y los modelos impuestos por la hegemonía del poder, incorporando a las dinámicas políticas y sociales que marcan el devenir del pueblo mapuche a las entidades sobrenaturales no-humanas que guían actualmente su acción política frente a las usurpaciones territoriales, la violencia y la marginación por parte de la sociedad dominante.
Al adoptar así una visión desde los términos y conceptos que ellos mismos nos proponen y, sobre todo, prestando especial atención a la relación entre los conceptos de “cosmo” y “política”, apostamos por una forma de entender la relación con los pueblos indígenas ajena a una perspectiva hegemónica del mundo que permita establecer un diálogo ontológico en igualdad.Throughout the centuries, indigenous rituals have been observed and interpreted from multiple perspectives, many of which have been subjugated to ethnocentric views which are a product of often invisible asymmetrical power relations that colonialism/coloniality has created. Under this ethnocentric perspective, alterity is viewed as a simple “object of study”
This project, applying the cosmopolitic approach, attempts to go beyond the anthropocentric view that we have easily accepted regarding nature and the world that surrounds us. Following this approach, nature and culture are regarded in a new light, where the above Western, anthropocentric conceptions lose the meanings that we have learnt and socially accepted. In this way, the following project explores the cosmopolitic perspective of the Ngillatun – ritual of the Mapuche people – as a means of subverting the modern political order and the models imposed by the hegemony of power. In order to do this, we will contribute to study of Mapuche’s social and political dynamics by exploring how non-human supernatural entities currently guide their actions against territorial usurpation, violence and marginalization by the dominant society.
In following this new approach, focusing on the terms and concepts that the Mapuche themselves propose to us, paying special attention to the relation between the concepts “cosmos” and “politics”, a new way to understand our relationship with indigenous peoples, alien to our hegemonic understanding of the world, is proposed which allows us to establish an ontological dialogue in terms of equality.Depto. de Historia de América y Medieval y Ciencias HistoriográficasFac. de Geografía e HistoriaTRUEunpu
Long term X-ray spectral variability of the nucleus of M81
We have analysed the soft X-ray emission from the nuclear source of the
nearby spiral galaxy M81, using the available data collected with ROSAT, ASCA,
BeppoSAX and Chandra. The source flux is highly variable, showing (sometimes
dramatic: a factor of 4 in 20 days) variability at different timescales, from 2
days to 4 years, and in particular a steady increase of the flux by a factor of
>~ 2 over 4 years, broken by rapid flares. After accounting for the extended
component resolved by Chandra, the nuclear soft X-ray spectrum (from
ROSAT/PSPC, BeppoSAX/LECS and Chandra data) cannot be fitted well with a single
absorbed power-law model. Acceptable fits are obtained adding an extra
component, either a multi-color black body (MCBB) or an absorption feature. In
the MCBB case the inner accretion disk would be far smaller than the
Schwartzchild radius for the 3-60X 10^6 solar masses nucleus requiring a
strictly edge-on inclination of the disk, even if the nucleus is a rotating
Kerr black hole. The temperature is 0.27 keV, larger than expected from the
accretion disk of a Schwartzchild black hole, but consistent with that expected
from a Kerr black hole. In the power-law + absorption feature model we have
either high velocity (0.3 c) infalling C_v clouds or neutral C_i absorption at
rest. In both cases the C:O overabundance is a factor of 10.Comment: 30 pages with 15 figures. Accepted for publication in the
Astrophysical Journa
Assessment of exposure to environmental tobacco smoke in young adolescents following implementation of smoke-free policy in Italy
We investigated acute and chronic exposure to environmental tobacco smoke (ETS) in a cohort of young adolescents using urinary cotinine and hair nicotine testing after recent implementation of Italian smoke free legislation. Study subjects were 372 Italian young adolescents, between 10 and 16 years of age from the principal city of Sicily, Palermo. Urine and hair samples were collected between November 2005 and May 2006, when the legislation to ban smoking in all the enclosed places of employment (including bars, restaurants, pubs) was completely enforced. An exhaustive questionnaire including sociodemographic characteristics and active and passive exposure to cigarette smoking was completed. Urinary cotinine was analyzed by radioimmunoassay and hair nicotine by a validated GC/MS method. Based on urinary cotinine results, 2.1% and 89% of the study participants, respectively, showed non-exposure and low acute exposure to ETS, whereas only 1.6% presented very high exposure or a hidden active smoking habit in the recent past. Hair nicotine disclosed non-exposure and low exposure to ETS in 11.8% and 65.6% of the young adolescents, respectively, taking into consideration a larger time-window. High repeated exposure, suggesting active smoking in some cases was observed in 8.6% of the study subjects. Hair nicotine was inversely related to educational level of the adolescents' parents. Overall, due to the implementation of smoke-free legislation and information campaign against smoking, a significant trend toward low exposure to ETS was observed in this study cohort with no association between exposure to ETS and respiratory illnesses
Topiramate Concentrations In Neonates Treated With Prolonged Whole Body Hypothermia For Hypoxic Ischaemic Encephalopathy
AMPK Activators as Novel Drug Candidates for the Treatment of Inflammatory Bowel Diseases
Inflammatory bowel diseases (IBDs), mainly represented by ulcerative colitis and Crohn’s disease, are chronic and idiopathic diseases of the digestive tract. They incidence and prevalence is raising significantly in both developed and developing countries, thus representing a major challenge for the worldwide healthcare systems. The pharmacological armamentarium for the treatment of IBDs is far from being satisfactory, as the therapeutic success of the available drugs is still limited. Accordingly, the development of novel and effective compounds is highly requested. In this context, the serine/threonine heterotrimeric kinase AMPK (adenosine monophosphate-activated protein kinase) seems a sound target to strike.
Known as the central hub of energy homeostasis in eukaryotic cells, AMPK contributes also to the modulation of immune/inflammatory cell functions. Actually, alterations in AMPK expression and/or activity play a key role in the pathophysiology of immune-mediated inflammatory diseases characterized by abnormal immune cell functions, like IBDs. Moreover, AMPK is able to improve intestinal health by enhancing para-cellular junctions, nutrient transporters, autophagy and apoptosis. Accordingly, AMPK activation represents a promising therapeutic strategy for the treatment of intestinal inflammatory disorders. Here we describe a novel heterocyclic derivative, developed as AMPK activator. Tested in C2C12 myoblast cell lines, our compound significantly increased AMPK activity, in a concentration-dependent manner, turning out to be more effective than the well-known activator acadesine (ACA). Moreover, assayed in a mouse model of acute DNBS-induced colitis, the novel heterocycle displayed a relevant anti-inflammatory efficacy, proving to ameliorate both systemic- and tissue-related inflammatory parameters like body and spleen weight, colon length, macroscopic damage, TNF and MDA levels. Also in this case, our compound turned out to be significantly more active that the known reference ACA, thus imposing itself as a novel and valuable drug candidate for the treatment of IBDs
An Extreme Mountain Ultra-Marathon Decreases the Cost of Uphill Walking and Running
Purpose: To examine the effects of the world's most challenging mountain ultramarathon (MUM, 330 km, cumulative elevation gain of +24,000 m) on the energy cost and kinematics of different uphill gaits. Methods: Before (PRE) and immediately after (POST) the competition, 19 male athletes performed three submaximal 5-min treadmill exercise trials in a randomized order: walking at 5 km.h-1, +20%; running at 6 km.h-1, +15%; and running at 8 km.h-1, +10%. During the three trials, energy cost was assessed using an indirect calorimetry system and spatiotemporal gait parameters were acquired with a floor-level high-density photoelectric cells system. Results: The average time of the study participants to complete the MUM was 129 h 43 min 48 s (range: 107 h 29 min 24 s to 144 h 21 min 0 s). Energy costs in walking (-11.5 +/- 5.5%, P < 0.001), as well as in the first (-7.2 +/- 3.1%, P = 0.01) and second (-7.0 +/- 3.9%, P = 0.02) running condition decreased between PRE and POST, with a reduction both in the heart rate (-11.3, -10.0, and -9.3%, respectively) and oxygen uptake only for the walking condition (-6.5%). No consistent and significant changes in the kinematics variables were detected (P-values from 0.10 to 0.96). Conclusion: Though fatigued after completing the MUM, the subjects were still able to maintain their uphill locomotion patterns noted at PRE. The decrease (improvement) in the energy costs was likely due to the prolonged and repetitive walking/running, reflecting a generic improvement in the mechanical efficiency of locomotion after ~130 h of uphill locomotion rather than constraints imposed by the activity on the musculoskeletal structure and function
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