Attività lisozima-simile e citotossica nel muco di Actina equina (Cnidaria, Anthozoa)

2008

A self-consistent approach to the hard and soft states of 4U 1705-44

2010

We analyzed two XMM-Newton observations of the bright atoll source 4U 1705-44, which can be considered a prototype of the class of the persistent NS LMXBs showing both hard and soft states. The first observation was performed when the source was in a hard low flux state, the second during a soft, high-flux state. Both the spectra show broad iron emission lines. We fit the spectra using a two-component model, together with a reflection model specifically suited to the case of a neutron star, where the incident spectrum has a blackbody shape. In the soft state, the reflection model, convolved with a relativistic smearing component, consistently describes the broad features present in the spec…

BeppoSAX observation of 4U 1705-44: detection of hard X-ray emission in the soft state

2007

4U 1705-44 is one of the best studied type I X-ray burster and atoll sources. Since it covers a wide range in luminosity (from a few to 50 x 10^{36} erg s^{-1}) and shows clear spectral state transitions, it represents a good laboratory to test the accretion models proposed for atoll sources. We analysed the energy spectrum accumulated with BeppoSAX observations (43.5 ksec) in August 2000 when the source was in a soft spectral state. The continuum of the wide band energy spectrum is well described by the sum of a blackbody (kT_{bb}~0.56 keV) and a Comptonized component (seed-photon temperature kT_W~1 keV, electron temperature kT_e~2.7 keV, and optical depth ~11). A hard tail was detected at…

Die Anwendung der Dynamischen Optimierung bei der Sozial-Sanitären Bezirkseinteilung

1979

Nach einer kurzen Analyse des Problems der optimalen Aufteilung eines geographischen Gebietes in sozial-sanitare Bezirke wird in der vorliegenden Arbeit fur die Losung eines solchen Problems ein Modell dynamischer Programmierung verwendet. Es werden dann zwei Algorithmen vorgeschlagen: der erste, der von der territorialen Einheit ausgeht, soll die zulassigen sozial-sanitaren Bezirke unter Berucksichtigung der Faktoren Nahe, Dichte und begrenzter Bevolke-rungsunterschied ermitteln; der zweite errechnet jene Gesamtheit der zulassigen Bezirke, die, jede territoriale Einheit nur einmal „deckend“, eine Zielfunktion auf ein Minimum reduziert, die das Gleichgewicht zwischen Angebot und Nachfrage d…

Broadband observations of the X-ray burster 4U1705-44 with Beppo SAX

2016

4U 1705-44 is one of the most-studied type I X-ray burster and Atoll sources. This source represents a perfect candidate to test different models proposed to self-consistently track the physical changes occurring between different spectral states because it shows clear spectral state transitions. The broadband coverage, the sensitivity and energy resolution of the BeppoSAX satellite offers the opportunity to disentangle the components that form the total X-ray spectrum and to study their changes according to the spectral state. Using two BeppoSAX observations carried out in August and October 2000, respectively, for a total effective exposure time of about 100 ks, we study the spectral evol…

A relativistic iron emission line from the neutron star low-mass X-ray binary GX 3+1

2012

We present the results of a spectroscopic study of the Fe K{\alpha} emission of the persistent neutron-star atoll low-mass X-ray binary and type I X-ray burster GX 3+1 with the EPIC-PN on board XMM-Newton. The source shows a flux modulation over several years and we observed it during its fainter phase, which corresponds to an X-ray luminosity of Lx~10^37 ergs/s. When fitted with a two-component model, the X-ray spectrum shows broad residuals at \sim6-7 keV that can be ascribed to an iron K{\alpha} fluorescence line. In addition, lower energy features are observed at \sim3.3 keV, \sim3.9 keV and might originate from Ar XVIII and Ca XIX. The broad iron line feature is well fitted with a rela…

A relativistically smeared spectrum in the neutron star X-ray binary 4U 1705−44: looking at the inner accretion disc with X-ray spectroscopy

2009

Iron emission lines at 6.4-6.97 keV, identified with fluorescent Kalpha transitions, are among the strongest discrete features in the X-ray band. These are therefore one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disc around a compact object. In this paper we present a recent XMM observation of the X-ray burster 4U 1705-44, where we clearly detect a relativistically smeared iron line at about 6.7 keV, testifying with high statistical significance that the line profile is distorted by high velocity motion in the accretion disc. As expected from disc reflection models, we also find a significant absorption edge at about 8.3 keV; th…

The reflection component in NS LMXBs

2014

Thanks to the good spectral resolution and large effective area of the EPIC/PN instrument on board of XMM-Newton, we have at hand a large number of observations of accreting low-mass X-ray binaries, that allow for the fist time a comprehensive view on the characteristics of the reflection component at different accretion regimes and to probe the effects of a magnetosphere on its formation. We focus here on a comparative analysis of the reflection component from a series of spectroscopic studies on selected sources: 4U 1705-44, observed both in the soft and hard state, the pulsating ms pulsars SAX J1808.4-3658 and IGR J17511-3057, and the intermittent pulsar HETE J1900-2455. Although the sou…

VALUTAZIONE DELLA QUALITA’ DEL LAVORO NEI CANTIERI DI TRAPIANTO MECCANICO DELLE BARBATELLE

2005

The aim of this paper is to assess the quality of the work performed by two machines for transplanting rooted vines, equipped with a laser alignment system, in a plain environment and known physical properties of the soil. Both the distances between plants and between rows with respect to the established one and the percent of missing plants were detected. The results, compared with those detected in a manual working team, showed that the quality of the work performed by the two transplanting machines is similar to that obtained in the manual working team.

Le condizioni dei dispositivi di sicurezza delle macchine operatrici in alcune aziende agricole siciliane

2004

The agricultural machines available in a sample of farms in the Central and Western Sicily were surveyed, in order to evaluate the compliance of their safety conditions with the related laws. Often the regulations of these laws resulted partially or totally not applied. Among the machines moved by p.t.o. the crop protection machines showed the best overall conditions while the harvesting and baling machines showed the worst ones; among the machines not moved by p.t.o. the trailers showed the best overall conditions while the ploughs showed the worst ones. These results are generally caused by an insufficient maintenance and/or the lack of protection and safety devices and/or the year of man…