641 research outputs found

    Plant Conservation Centres in Sicily: The ‘Valle Maria’ Regional Centre (Godrano, Palermo) and the case study of the rare Centaurea erycina (Asteraceae).

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    The role of the ‘Valle Maria’ Regional Centre and its activity in plant conservation thank to the collaboration with the University of Palermo, Dept. STEBICEF is discussed. The case study on propagation of Centaurea erycina, a narrow Sicilian endemic is presented

    Non-linear unbalanced Bessel beams: Stationary conical waves supported by nonlinear losses

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    Nonlinear losses accompanying Kerr self-focusing substantially impacts the dynamic balance of diffraction and nonlinearity, permitting the existence of localized and stationary solutions of the 2D+1 nonlinear Schrodinger equation which are stable against radial collapse. These are featured by linear conical tails that continually refill the nonlinear, central spot. An experiment shows that the discovered solution behaves as strong attractor for the self-focusing dynamics in Kerr media.Comment: 4 pages, 2 figures; experimental verification adde

    Space-Time Recovery of Arbitrarily Shaped Wave-Packets by Means of Three Dimensional Imaging Technique

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    We study numerically and experimentally self-focusing dynamics of femtosecond light pulses. By demonstrating the potential of three dimensional imaging technique for quantitative recovery of complex (arbitrarily shaped) wave packets, we monitor space-time transformation dynamics of 150-fs light pulse, which undergoes self-focusing and filamentation in water. Peculiar spatiotemporal and spectral features reveal conical nature of resulting wave-packet

    Culinary tourism experiences in agri-tourism destinations and sustainable consumption-Understanding Italian tourists' motivations

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    Culinary tourism represents an emerging component of the tourism industry and encompasses all the traditional values associated with the new trends in tourism: respect for culture and tradition, authenticity and sustainability. Italy is known worldwide for the richness and variety of its gastronomy, and agri-tourism represents one of the most important places where culinary tourists can experience local food and beverages. By using a modified version of Kim and Eves’ motivational scale, the present study aims to investigate which motivational factors aect the frequency of culinary tourists to experience local food and beverages in agri-tourism destinations. The findings of the present study reveal that the social and environmental sustainability, among the other motivations, has shown to play a crucial role in influencing Italian tourists’ frequency to experience local food and beverage in agri-tourism destinations

    Optimal design algorithm for seismic retrofitting of RC columns with steel jacketing technique

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    Steel jacketing (SJ) of beams and columns is widely employed as retrofitting technique to provide additional deformation and strength capacity to existing reinforced concrete (RC) frame structures. The latter are many times designed without considering seismic loads, or present inadequate seismic detailing. The use of SJ is generally associated with non-negligible costs depending on the amount of structural work and non-structural manufacturing and materials. Moreover, this kind of intervention results in noticeable downtime for the building. This paper presents a new optimization framework which is aimed at obtaining minimization of retrofitting costs by optimizing the position and the amount of steel jacketing retrofitting. The proposed methodology is applied to the case study of a 3D RC frame realized in OpenSEES and handled within the framework of a genetic algorithm. The algorithm iterates geometric and mechanical parameters configurations, based on the outcomes of static pushover analysis, in order to match the optimal retrofitting solution, intended as the one minimizing the costs and, at the same time, maintaining a specified safety level. Results of the proposed framework will provide optimized location and amount of steel-jacketing reinforcement. It is finally shown that the use of engineering optimization methods can be effectively used to limit retrofitting costs without a substantial modification of structural safety

    Characterization of charge sharing and fluorescence effects by multiple counts analysis in a Pixie-II based detection system

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    In CdTe X-ray photon counting detectors (PCD) featuring small pixel sizes (<100μm), charge-sharing and fluorescences emitted by Cd and Te are responsible for multiple counts from a single interacting photon. These effects can impair the imaging and spectroscopic performance of PCDs. Multiple counts can be partially or totally discriminated by properly setting the energy threshold implemented by the PCD system. Using monochromatic radiation and the Pixirad-1/Pixie-II CdTe PCD, this work characterizes and quantifies clusters of multiple counts as a function of energy and threshold

    PRIMI DATI SUGLI INNESTI DI ABIES NEBRODENSIS (LOJAC.) MATTEI ESEGUITI SU ABETI ESOTICI NELL\u2019AREA DI INDIGENATO (MADONIE)

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    C2 = PRIMI DATI SUGLI INNESTI DI ABIES NEBRODENSIS (LOJAC.) MATTEI ESEGUITI SU ABETI ESOTICI NELL\u2019AREA DI INDIGENATO (MADONIE) R. SCHICCHI, P. BONOMO, M. CANDORE, G. DI NOTO, A. PUCCI, F. TRAPANI, P. MARINO Dipartimento di Biologia Ambientale e Biodiversit\ue0 dell'Universit\ue0, via Archirafi 38, 90123 Palermo (I) [email protected] Abies nebrodensis \ue8 una specie endemica relitta, gravemente minacciata di estinzione, la cui popolazione naturale \ue8 costituita da 30 individui distribuiti discontinuamente in una piccola area del territorio di Polizzi Generosa, all\u2019interno del Parco naturale delle Madonie in Sicilia. La minaccia di estinzione \ue8 dovuta, oltre all'esiguit\ue0 della popolazione, al ridotto numero di piante mature (ventiquattro) e al pericolo di inquinamento genetico incombente. A partire dall\u2019inizio degli anni \u201880 del secolo scorso, infatti, sono stati introdotti nella vicinanze dell\u2019area di indignato individui di abeti esotici (Abies alba Mill., A. cephalonica Loudon, e A. nordmanniana (Stefen) Spach) che, avendo raggiunto la maturit\ue0 sessuale, potrebbero mettere a rischio l\u2019integrit\ue0 genetica della progenie dell\u2019abete locale (Raimondo & Schicchi, 2005). Nell\u2019ambito del progetto \u201cConservazione di Abies nebrodensis e ripristino delle torbiere di Geraci Siculo\u201d, in corso di attuazione da parte dell\u2019Ente Parco delle Madonie, del Dipartimento di Biologia ambientale e Biodiversit\ue0 di Palermo e di altri partners locali, un\u2019azione di salvaguardia prevede l\u2019innesto degli abeti esotici con marze di A. nebrodensis, valorizzando la positiva esperienza effettuata con il progetto Life Natura (1). A tal fine, nel periodo compreso tra la terza decade di aprile e la seconda decade di maggio sono stati effettuati circa 350 innesti in contrada Comunello, nel territorio di Isnello. Le marze sono state prelevate da individui maturi di A. nebrodensis di oltre 30 anni di et\ue0, introdotti nelle opere di ripopolamento che, in seguito ai risultati delle analisi genetiche, sono geneticamente correlati agli esemplari della popolazione naturale. Gli innesti sono stati eseguiti a spacco ma soprattutto a corona, previa capitozzatura dei soggetti di A. alba e A. cephalonica, a un\u2019altezza di circa 2 m per evitare possibili danneggiamenti da parte del bestiame. Nei soggetti sono stati, comunque, rilasciati temporaneamente alcuni palchi che, continuando a svolgere le normali funzioni vitali, agevoleranno l\u2019attecchimento delle marze. Queste ultime sono state opportunamente sagomate e inserite tra la corteccia e il legno sia nel fusto capitozzato che in alcuni rami laterali. Esse sono state tenute strettamente aderenti ai soggetti tramite nastro adesivo e protette da due sacchetti, rispettivamente di polietilene e di carta, per creare condizioni micro-climatiche ottimali alla sopravvivenza delle marze. Dalla terza decade di maggio \ue8 iniziato, con cadenza settimanale, il monitoraggio degli innesti e la foratura, ove necessario, del sacchetto di plastica per eliminare l\u2019umidit\ue0 in eccesso. Dopo 40 giorni \ue8 stato possibile constatare che oltre il 90% degli innesti \ue8 attecchito. Anche alcuni innesti eseguiti a scopo sperimentale su Pseudotsuga menziesii Franco sono vitali. Durante la fine di luglio e agosto si prevede una graduale scopertura delle marze. Gli esiti di questa azione, tuttavia, potranno essere valutati compiutamente all\u2019inizio della prossima primavera. La tecnica dell\u2019innesto riveste notevole importanza poich\ue9 permette di eliminare o ridurre una delle minacce pi\uf9 consistenti a carico della popolazione naturale di A. nebrodensis, trasformando la stessa in un punto di forza nell\u2019ambito della strategia di conservazione della specie. Essa, infatti, potr\ue0 contribuire a incrementare la popolazione dell\u2019endemico A. nebrodensis, valorizzando come portainnesti piante che se non abbattute costituirebbero un serio pericolo per la conservazione dell\u2019abete delle Madonie. Raimondo F. M., Schicchi R., 2005. Rendiconto sul progetto LIFE Natura n\ub0 LIFE2000NAT/IT/7228 \u201cConservazione in situ ed ex situ di Abies nebrodensis (Lojac.) Mattei\u201d. Tipolitografia Luxograph, Palermo

    Hodgkin's disease presenting below the diaphragm. The experience of the Gruppo Italiano Studio Linfomi (GISL)

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    Background and Objective. Infradiaphragmatic Hodgkin\ub4s disease is rare, making up 5-12% of cases in clinical stages I and II; consequently, several questions concerning prognosis and treatment strategy remain to be answered. The aim of this study was to analyze the clinical and prognostic characteristics and outcome of his condition. Methods. A series of 282 patients with CS I-II Hodgkin\ub4s disease (HD) was investigated. In 31 patients the disease was confined below the diaphragm (BDHD), and in the remaining above the diaphragm (ADHD). The presenting features and outcomes were compared in the two groups. Results. The BDHD group was older (p < 0.0002), had a higher frequency of males (p < 0.08) and a different histological subtype group distribution (p < 0.0001). Stage II BDHD patients had a worse overall survival rate (OS) than stage II ADHD patients (68.8% vs 86.6% at 8 years, p < 0.01) if age is not considered; patients with more than 40 years of age, in fact, had the same survival rates as those with ADHD. BDHD patients with intra-abdominal disease alone had worse prognostic factors and OS (p = 0.12) than patients with inguinal-femoral nodes. Interpretation and Conclusions. Although BDHD patients present distinct features, they have the same OS and relapse-free survival rate as age-adjusted ADHD patients. According to our experience patients with stage I peripheral BDHD respond well to radiotherapy-based regimens. Those with stage II and or intra-abdominal disease are more challenging; chemotherapy or a combined therapy seem to be more suitable approaches for these patients

    Detection of sub-shot-noise spatial correlation in high-gain parametric down-conversion

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    Using a 1GW-1ps pump laser pulse in high gain parametric down-conversion allows us to detect sub-shot-noise spatial quantum correlation with up to one hundred photoelectrons per mode, by means of a high efficiency CCD. The statistics is performed in single-shot over independent spatial replica of the system. The paper highlights the evidence of quantum correlation between symmetrical signal and idler spatial areas in the far field, in the high gain regime. In accordance with the predictions of numerical calculations the observed transition from the quantum to the classical regime is interpreted as a consequence of the narrowing of the down-converted beams in the very high gain regime.Comment: 4,2 pages, 4 figure
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