373 research outputs found
Characterizing Synchronization in Time Series using Information Measures Extracted from Symbolic Representations
We present a methodology to characterize synchronization in time series based
on symbolic representations. A symbol is linked to a sequence of numbers
through the rank-order of its values. A representation of a time series results
after mapping all sequences into symbols. We propose a transcription scheme
between symbolic representations to study the dynamics of coupled systems. This
scheme allows us to use elements of group theory and to derive information
measures to assess the degree of synchronization. We apply our method to a
prototype non-linear system which displays a rich coupled dynamics.Comment: 9 pages, 4 figure
PMS66 Determinants of Non-Persistence to Antiosteoporotic Drugs by Using Administrative Database
Osteoporosis treatment involves several therapeutic tools, including long-term drug therapy. Subjects with chronic disorders are more likely to be non-adherent and/or non-persistent to treatment than those with other diseases. Adherence is the extent to which patients take medication as prescribed by their physicians, whereas persistence is the time from treatment initiation to discontinuation. Lack of persistence is common among subjects using oral anti-osteoporotic drugs, and leads to increased risk of fragility fracture
Una procedura per la valutazione dei limiti di utilizzo di O-Ring sottoposti ad intensi fasci di neutroni
Si presenta una procedura per la previsione della durata di utilizzo di O-ring in materiale polimerico impiegati nei bersagli per la produzione di fasci di ioni radioattivi. Si sono dapprima condotte prove di tenuta a vuoto e analisi a elementi finiti di un O-ring di riferimento operante con diversi livelli di interferenza con la cava, identificando la precompressione limite per la tenuta e la corrispondente pressione di contatto con la cava. Si sono poi effettuate prove di trazione e di Compression Set su campioni di O-ring in EPDM, preventivamente sottoposti a diversi livelli di irraggiamento in campi misti di neutroni e gamma, analizzando l’effetto della dose assorbita sul comportamento meccanico del materiale e sulle corrispondenti proprietà resistenziali, e definendo opportune leggi costitutive. Si sono infine simulate le progressive modifiche di comportamento della guarnizione indotte dall’irraggiamento, prevedendone la durata in esercizio in termini di tenuta e di resistenza strutturale
Oxidative Stress and NO Signalling in the Root Apex as an Early Response to Changes in Gravity Conditions.
Oxygen influx showed an asymmetry in the transition zone of the root apex when roots were placed horizontally on ground. The influx increased only in the upper side, while no changes were detected in the division and in the elongation zone. Nitric oxide (NO) was also monitored after gravistimulation, revealing a sudden burst only in the transition zone. In order to confirm these results in real microgravity conditions, experiments have been set up by using parabolic flights and drop tower. The production of reactive oxygen species (ROS) was also monitored. Oxygen, NO, and ROS were continuously monitored during normal and hyper- and microgravity conditions in roots of maize seedlings. A distinct signal in oxygen and NO fluxes was clearly detected only in the apex zone during microgravity, with no significant changes in normal and in hypergravity conditions. The same results were obtained by ROS measurement. The detrimental effect of D’orenone, disrupting the polarised auxin transport, on the onset of the oxygen peaks during the microgravity period was also evaluated. Results indicates an active role of NO and ROS as messengers during the gravitropic response, with probable implications in the auxin redistribution
Volcanic forcing improves Atmosphere-Ocean Coupled General Circulation Model scaling performance
Recent Atmosphere-Ocean Coupled General Circulation Model (AOGCM) simulations
of the twentieth century climate, which account for anthropogenic and natural
forcings, make it possible to study the origin of long-term temperature
correlations found in the observed records. We study ensemble experiments
performed with the NCAR PCM for 10 different historical scenarios, including no
forcings, greenhouse gas, sulfate aerosol, ozone, solar, volcanic forcing and
various combinations, such as it natural, anthropogenic and all forcings. We
compare the scaling exponents characterizing the long-term correlations of the
observed and simulated model data for 16 representative land stations and 16
sites in the Atlantic Ocean for these scenarios. We find that inclusion of
volcanic forcing in the AOGCM considerably improves the PCM scaling behavior.
The scenarios containing volcanic forcing are able to reproduce quite well the
observed scaling exponents for the land with exponents around 0.65 independent
of the station distance from the ocean. For the Atlantic Ocean, scenarios with
the volcanic forcing slightly underestimate the observed persistence exhibiting
an average exponent 0.74 instead of 0.85 for reconstructed data.Comment: 4 figure
An algorithm to calculate the transport exponent in strip geometries
An algorithm for solving the random resistor problem by means of the
transfer-matrix approach is presented. Preconditioning by spanning clusters
extraction both reduces the size of the conductivity matrix and speed up the
calculations.Comment: 17 pages, RevTeX2.1, HLRZ - 97/9
Fixed Versus Free Combinations of Antihypertensive Drugs: Analyses Of Real-World Data Of Persistence With Therapy In Italy
Purpose: To analyse the pattern of use and cost of antihypertensive drugs in new users in an Italian population, and explore the patient/treatment factors associated with the risk of therapy discontinuation. Patients and methods: In this retrospective study, information was collected from a population-based electronic primary-care database. Persistence with medication use 1 year from therapy initiation was evaluated for each user using the gap method. Each new user was classified according to his/her pattern of use as: \u201ccontinuer\u201d, \u201cdiscontinuer\u201d \u201cswitching\u201d or \u201cadd-on\u201d. A Cox regression model was used to analyse the factors influencing therapy discontinuation. Primary-care costs comprised specialists\u2019 visits, diagnostic procedures and pharmacologic therapies. Results: Among 14,999 subjects included in persistence analyses, 55.1% of cases initially started on monotherapy were classified as discontinuers vs 36.5% of cases taking combination therapy (42.3% vs 32.7%, respectively, for free and fixed combinations, P < 0.01). Old age, high cardiovascular risk and being in receipt of fixed-combination therapy were associated with greater persistence. Overall, the primary-care cost/person/year of hypertension management was 3c\u20ac95.3 (IQR, 144.9). The monotherapy cost was \u20ac88 per patient (IQR, 132.9), and that for combination therapy was \u20ac151\ub1148.3. The median cost/patient with a fixed combination was lower than that for a free combination (\u20ac98.4 (IQR, 155.3) and \u20ac154.9 (IQR, 182.6), respectively). Conclusion: The initial type of therapy prescribed influences persistence. Prescribing fixed combinations might be a good choice as initial therapy
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DHS Regional Reachback: Rapid Expert Radiation Alarm Assistance.
Following assessments that attacks with radiological and nuclear weapons are possible, detection system deployments are being supported at national and local levels. Detection systems include both, highly sensitive but non-discriminating detectors, as well as detectors and algorithms capable of distinguishing and identifying gamma rays by energy. The latter systems, usually handheld systems based on sodium iodide detectors, also provide analysis of the specific radionuclides present and are referred to as radioisotope identifiers (RIIDs). Studies have shown that sodium iodide based RIIDs fall far short of 100% accurate identifications. The U.S. Department of Homeland Security (DHS) initiated the Regional Reachback (RRB) Program in 2006 to provide rapid expert interpretation of gamma spectroscopic data from radiation alarms from detection systems deployed by state and local authorities. With expert specialists on call 24/7, RRB provides an avenue for local and state authorities to verify routine results, interpret unknown identifications, and notify national response assets if needed. This paper will provide details of the RRE3 program, an outline of the analysis process, a description of the drills and training systems used to maintain specialists response performance, and examples of drills and incidents from the first full year of operation
the isolpharm project a new isol production method of high specific activity beta emitting radionuclides as radiopharmaceutical precursors
The ISOLPHARM project explores the feasibility of exploiting an innovative technology to produce extremely high specific activity beta-emitting radionuclides as radiopharmaceutical precursors. This technique is expected to produce radiopharmaceuticals that are virtually mainly impossible to obtain in standard production facilities, at lower cost and with less environmental impact than traditional techniques. The groundbreaking ISOLPHARM method investigated in this project has been granted an international patent (INFN). As a component of the SPES (Selective Production of Exotic Species) project at the Istituto Nazionale di Fisica Nucleare–Laboratori Nazionali di Legnaro (INFN–LNL), a new facility will produce radioactive ion beams of neutron-rich nuclei with high purity and a mass range of 80–160 amu. The radioactive isotopes will result from nuclear reactions induced by accelerating 40 MeV protons in a cyclotron to collide on a target of UC[Formula: see text]. The uranium in the target material will be [Formula: see text]U, yielding radioactive isotopes that belong to elements with an atomic number between 28 and 57. Isotope separation on line (ISOL) is adopted in the ISOLPHARM project to obtain pure isobaric beams for radiopharmaceutical applications, with no isotopic contaminations in the beam or subsequent trapping substrate. Isobaric contaminations may potentially affect radiochemical and radionuclide purity, but proper methods to separate chemically different elements can be developed
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