133 research outputs found

    Grid Data Management in Action: Experience in Running and Supporting Data Management Services in the EU DataGrid Project

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    In the first phase of the EU DataGrid (EDG) project, a Data Management System has been implemented and provided for deployment. The components of the current EDG Testbed are: a prototype of a Replica Manager Service built around the basic services provided by Globus, a centralised Replica Catalogue to store information about physical locations of files, and the Grid Data Mirroring Package (GDMP) that is widely used in various HEP collaborations in Europe and the US for data mirroring. During this year these services have been refined and made more robust so that they are fit to be used in a pre-production environment. Application users have been using this first release of the Data Management Services for more than a year. In the paper we present the components and their interaction, our implementation and experience as well as the feedback received from our user communities. We have resolved not only issues regarding integration with other EDG service components but also many of the interoperability issues with components of our partner projects in Europe and the U.S. The paper concludes with the basic lessons learned during this operation. These conclusions provide the motivation for the architecture of the next generation of Data Management Services that will be deployed in EDG during 2003.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, LaTeX, PSN: TUAT007 all figures are in the directory "figures

    Photoelastic coupling in gallium arsenide optomechanical disk resonators

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    We analyze the magnitude of the radiation pressure and electrostrictive stresses exerted by light confined inside GaAs semiconductor WGM optomechanical disk resonators, through analytical and numerical means, and find the electrostrictive force to be of prime importance. We investigate the geometric and photoelastic optomechanical coupling resulting respectively from the deformation of the disk boundary and from the strain-induced refractive index changes in the material, for various mechanical modes of the disks. Photoelastic optomechanical coupling is shown to be a predominant coupling mechanism for certain disk dimensions and mechanical modes, leading to total coupling gom_{om} and g0_0 reaching respectively 3 THz/nm and 4 MHz. Finally, we point towards ways to maximize the photoelastic coupling in GaAs disk resonators, and we provide some upper bounds for its value in various geometries

    Influence of metabolic syndrome on hypertension-related target organ damage

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    OBJECTIVES: The aim of our study was to analyse, in a wide group of essential hypertensive patients without diabetes mellitus, the influence of metabolic syndrome (MS) (defined according to the criteria laid down in the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults) on markers of preclinical cardiac, renal and retinal damage. DESIGN: Cross-sectional study. SETTING: Outpatient hypertension clinic. SUBJECTS AND METHODS: A total of 353 young and middle-aged hypertensives, free from cardiovascular and renal diseases (and 37% of whom had MS), underwent echocardiographic examination, microalbuminuria determination and non-mydriatic retinography. RESULTS: When compared with subjects without MS, hypertensive patients with MS exhibited more elevated left ventricular (LV) mass (either normalized by body surface area or by height elevated by a power of 2.7), higher myocardial relative wall thickness, albumin excretion rate (AER) and a greater prevalence of LV hypertrophy (57.7% vs. 25.1%; P < 0.00001), of microalbuminuria (36.2% vs. 19.3%; P = 0.002) and of hypertensive retinopathy (87.7% vs. 48.4%; P < 0.00001). These results held even after correction for age, 24-h blood pressures, duration of hypertension, previous antihypertensive therapy, and gender distribution. The independent relationships between LV mass and MS, and between AER and MS, were confirmed in multivariate regression models including MS together with its individual components. CONCLUSIONS: MS may amplify hypertension-related cardiac and renal changes, over and above the potential contribution of each single component of this syndrome. As these markers of target organ damage are well-known predictors of cardiovascular events, our results may partly explain the enhanced cardiovascular risk associated with MS

    Gulliver - Guided Navigation inside the Computer

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    Gulliver was born from the requirement for a tool able to develop computers architecture projects primarily for didactic purposes. Using Gulliver it is possible:- to define computei.- architectures in an incremental way, starting from a minimal structure building up to more complex ones;- to define symbolic program languages coherently with the model of the architecture implemented;- to simulate functionality of the architecture and the language proposed for each stage of the development.Such a system is of considerable utility both for the teacher, who can strengthen the effect of a traditional lesson by simple experiments directed at the topic to be deepened, and for the student as an instrument of study and/or for the autoevaluation of the learning level acquired in the subject. Finally, Gulliver can be considered to be the nucleus of a development tool for system architectural projects

    Relationship between albumin excretion rate and aortic stiffness in untreated essential hypertensive patients

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    OBJECTIVES: To evaluate, in a group of nondiabetic essential hypertensive patients with normal renal function, the relationship between albumin excretion rate (AER) and carotid-femoral pulse wave velocity (PWV), as an index of aortic stiffness. DESIGN: Cross-sectional study. SETTING: Outpatient hypertension clinic. SUBJECTS: Seventy patients with mild-to-moderate essential hypertension, aged 42 +/- 8 years, never pharmacologically treated. All subjects underwent routine laboratory tests, 24-h ambulatory blood pressure (BP) monitoring, measurement of carotid-femoral PWV, by means of a computerized method, and AER. RESULTS: Microalbuminuric patients (AER > or = 20 microg min(-1); n = 19), when compared with normoalbuminuric subjects, showed more elevated 24-h BP (136/88 +/- 10/10 vs. 128/83 +/- 7/6 mmHg; P < 0.001 and P = 0.013, for systolic and diastolic BP respectively) and higher values of carotid-femoral PWV (10.4 +/- 2 m s(-1) vs. 9.2 +/- 1.3; P = 0.006). This latter difference remained statistically significant, even after correction by ancova for 24-h systolic and diastolic BP, and body mass index (BMI, P = 0.016). Univariate regression analysis disclosed a tight correlation between AER and carotid-femoral PWV (r = 0.42; P = 0.0003). This association was confirmed in a multiple regression model (beta = 0.35; P = 0.009) in which, as independent variables, besides PWV, 24-h BP, age, serum glucose values, smoking status, gender and BMI, were added. CONCLUSIONS: Our results seem to confirm that microalbuminuria may represent the early renal manifestation of a widespread vascular dysfunction, and therefore it is an integrated marker of cardiovascular risk

    test of cloud federation in chain reds project

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    Cloud Computing is considered a successful technology, involving distributed computation infrastructures, which take advantage of the virtualization of physical resources to actuate useful scale economies. In cloud ecosystems today, attention increasingly focuses on cooperation issues, mostly in the wider context of federation. Cloud federation refers to the process of interconnecting different cloud infrastructures for resource load balancing and to manage demand spikes. One of the biggest advantages of a federated cloud consists of the possibility of distributing the workload over different cloud providers, rather than obtaining cloud services from just a single supplier. In addition, federation could be very important for Big Data, for example, to implement policies allowing migration for virtual machines involved in data analysis next to storage hosting Big Data. Federation, automation, standards, and interoperability are crucial for cloud computing services to be successful in the near future. Standards are crucial for both interoperability and federation, and federation is the first step toward interoperability. The idea we describe in this paper comes from the assumption that some of Cloud Infrastructure offering IaaS (e.g., OpenStack, OpenNebula) provide interfaces based on the OCCI standard, but lack an interconnecting cooperation/federation awareness layer. We propose a software infrastructure able to provide a homogeneous interface among different Cloud managers, in order to coordinate the IaaS resources in a transparent and distributed manner. We have implemented such software, based on CLEVER, a novel Cloud Middleware jointly developed by INFN Catania and the University of Messina, which uses XMPP as interconnecting communication protocol. We also present: an interface for the Catania Science Gateway Framework implementing a simple dashboard a testbed used in the framework of the CHAIN-REDS Project, which includes sites belonging to the EGI Federated Cloud. This work shows that cloud federation using standards is feasible

    A Model for Accomplishing and Managing Dynamic Cloud Federations

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    Cloud computing is not just a promising approach to the service provisioning: nowadays it represents the reference model in such field. Several cloud service providers have emerged as de facto standards and an increasing number of companies are choosing to migrate their business in the Cloud "ecosystem". Nevertheless, each provider adopts a particular interface to manage its services and uses a proprietary technology. In this paper we present a cloud federation model which is able to provide scalability and flexibility to small clouds. The idea is to benefit of renting seamless resources according to federation agreements among operators. The challenge here is to overcome all the problems raising trying to merge small clouds with heterogeneous administrative domains

    Crowded space: A review on radar measurements for space debris monitoring and tracking

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    Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous review has been done in this paper, in order to find and classify the considerable amounts of data provided by the scientific community that deal with RADAR measurement for the debris monitoring and tracking. The information gathered is organized based on the volume of found data and classified taking into account the geographical location of the facilities

    Monitoring the December 2015 summit eruptions of Mt. Etna (Italy): Implications on eruptive dynamics

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    A lengthy period of eruptive activity fromthe summit craters ofMt. Etna started in January 2011. It culminated in early December 2015 with a spectacular sequence of intense eruptive events involving all four summit craters (Voragine, Bocca Nuova,NewSoutheast Crater, and Northeast Crater). The activity consisted of high eruption columns, Strombolian explosions, lava flows andwidespread ash falls that repeatedly interferedwith air traffic. The most powerful episode occurred on 3 December 2015 from the Voragine. After three further potent episodes fromthe Voragine, activity shifted to the NewSoutheast Crater on 6 December 2015, where Strombolian activity and lava flow emission lasted for two days and were fed by the most primitive magma of the study period. Activity once more shifted to the Northeast Crater, where ash emission and weak Strombolian activity took place for several days. Sporadic ash emissions from all craters continued until 18 December, when all activity ceased. Although resembling the summit eruptions of 1998–1999, which also involved all four summit craters, thismultifaceted eruptive sequence occurred in an exceptionally short time window of less than three days, unprecedented in the recent activity of Mt. Etna. It also produced important morphostructural changes of the summit area with the coalescence of Voragine and Bocca Nuova in a single large crater, the “Central Crater”, reproducing themorphological setting of the summit cone before the formation of Bocca Nuova in 1968. The December 2015 volcanic crisis was followed closely by the staff of the Etna Observatory to monitor the on-going activity and forecast its evolution, in accordance with protocols agreed with the Italian Civil Protection Department.Published53-695V. Dinamica dei processi eruttivi e post-eruttiviJCR Journa

    Quantitative value of aldosterone-renin ratio for detection of aldosterone-producing adenoma: The Aldosterone-Renin Ratio for Primary Aldosteronism (AQUARR) study

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    Background Current guidelines recommend use of the aldosterone\u2010renin ratio (ARR) for the case detection of primary aldosteronism followed by confirmatory tests to exclude false\u2010positive results from further diagnostic workup. We investigated the hypothesis that this could be unnecessary in patients with a high ARR value if the quantitative information carried by the ARR is taken into due consideration. Methods and Results We interrogated 2 large data sets of prospectively collected patients studied with the same predefined protocol, which included the captopril challenge test. We used an unambiguous diagnosis of aldosterone\u2010producing adenoma as reference index. We also assessed whether the post\u2010captopril ARR and plasma aldosterone concentration fall furnished a diagnostic gain over baseline ARR values. We found that the false\u2010positive rate fell exponentially, and, conversely, the specificity increased with rising ARR values. At receiver operating characteristics curves and diagnostic odds ratio analysis, the high baseline ARR values implied very high positive likelihood ratio and diagnostic odds ratio values. The baseline and post\u2010captopril ARR showed similar diagnostic accuracy (area under the receiver operating characteristics curve) in both the exploratory and validation cohorts, indicating lack of diagnostic gain with this confirmatory test (between\u2010area under the curve difference, 0.005; 95% CI, 120.031 to 0.040; P=0.7 for comparison, and 0.05; 95% CI, 120.061 to 0.064; P=0.051 for comparison, respectively). Conclusions These results indicate that the ARR conveys key quantitative information that, if properly used, can simplify the diagnostic workup, resulting in saving of money and resources. This can offer the chance of diagnosis and ensuing adrenalectomy to a larger number of hypertensive patients, ultimately resulting in better control of blood pressure
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