891 research outputs found

    Collective instabilities and collisional effects for a 2D model of a beam in a storage ring

    Get PDF
    We consider a collisional 2D model for a beam in a ring. In the smooth focusing approximation the relaxation time scales according to Landau’s theory, but the p.d.f of momentum jumps has a power law decaying queue. A new hybrid regime is found for the equipartitioning due to the interplay between collisional and collective effects. The moments equations of a small perturbation to the KV distribution are analytically determined and the stability conditions follow from Floquet’s theory

    Chemical investigation of a biologically active schinus molle L. leaf extract

    Get PDF
    The pepper tree Schinus molle L. is an evergreen ornamental plant belonging to the Anacardiaceae family, native to South America and widespread throughout the world. It has biological activities and is used in folk medicine. This paper aims to contribute to a deeper knowledge of its chemical composition and biological properties. S. molle leaf extracts were obtained by sequential extraction with solvents of different polarities and subsequently tested on the HL-60 human leukaemia cell line to define a possible cytotoxic activity. Among the investigated extracts, the petroleum ether extract revealed a high cytotoxic activity, and its chemical composition was further investigated. By a silica column chromatography, eight fractions were obtained, and their compositions were determined by GC-MS analysis. Compounds and relative abundance differed widely among the fractions; sesquiterpenes resulted the main component and alcoholic sesquiterpenes the most abundant

    Liquid and vapour phase of lavandin (Lavandula Ă— intermedia) essential oil: chemical composition and antimicrobial activity

    Get PDF
    Essential oils from Lavandula genus and the obtained hybrids are widely used for different purposes such as perfume production in the cosmetic field and for its biological properties. This is the first study on the liquid and vapour phase of Lavandula × intermedia “Grosso” essential oil grown in the Lazio Region, Italy, investigated using headspace coupled to gas chromatography and mass spectrometry (HS-GC/MS). The results showed the most abundant components were linalool and linalyl acetate, followed by 1,8-cineole and terpinen-4-ol, while lavandulyl acetate and borneol were identified as minor compounds, maintaining the same proportion in both the liquid and vapour phase. Furthermore, we tested lavandin liquid and vapour phase essential oil on gram-negative bacteria (Escherichia coli, Acinetobacter bohemicus, and Pseudomonas fluorescens) and gram-positive bacteria (Bacillus cereus and Kocuria marina)

    Stability change of Fourth-Order Resonance with application to Multi-Turn Extraction Schemes

    Get PDF
    Recently, a novel multi-turn extraction scheme was proposed, based on particle trapping inside stable resonances. Numerical simulations and experimental tests conirmed the feasibility of such a scheme for low order resonances. While the 3rd order resonance is generically unstable and those higher than 4th order are generically stable, the 4th order resonance can be either stable or unstable depending on the details of the system under consideration. By means of the normal form approach a general formula to control the stability of the 4th order resonance is derived. Numerical simulations confirm the analytical results and show that by crossing the unstable 4th order resonance the region around the centre of phase space is depleted and particles are trapped only in the four stable islands. This indicates that a four-turn extraction could be envisaged based on this technique

    The social cost of rheumatoid arthritis in Italy: the results of an estimation exercise.

    Get PDF
    The objective of this study is to estimate the mean annual social cost per adult person and the total social cost of rheumatoid arthritis (RA) in Italy. A literature review was performed by searching primary economic studies on adults in order to collect cost data of RA in Italy in the last decade. The review results were merged with data of institutional sources for estimating - following the methodological steps of the cost of illness analysis - the social cost of RA in Italy. The mean annual social cost of RA was € 13,595 per adult patient in Italy. Affecting 259,795 persons, RA determines a social cost of € 3.5 billions in Italy. Non-medical direct cost and indirect cost represent the main cost items (48% and 31%) of the total social cost of RA in Italy. Based on these results, it appears evident that the assessment of the economic burden of RA solely based on direct medical costs evaluation gives a limited view of the phenomenon
    • …
    corecore