879 research outputs found

    A new sample of bright galaxy pairs in UZC

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    We present a new sample of bright galaxy pairs extracted applying an objective selection code to UZC catalog.The sample is volume limited to Mzw_{zw} = -18.9 +5 log h{\it h} and contains 89 galaxy pairs.We analyze the kinematical, morphological and photometrical properties of galaxies belonging to this sample. We show that velocity separation, ∣Δvr∣| \Delta v_{r} |, between pair members is significantly lower in spiral type (S+S) pairs than in early-type (E+E) and mixed (E+S) pairs.This indicates that truly isolated galaxy pairs are more likely to be found among S+S pairs. We show that ellipticals are rare and underluminous in B and that late spirals (T ≄\ge 4) are overluminous. We confirm that the formation of bright ellipticals is a phenomenon linked to group/cluster environment, while galaxy-galaxy interaction may enhance blue luminosity of disk galaxies through SF phenomena. This last statement is supported by the presence of strong FIR emission from early spirals in this sample and by the high frequency of AGN/SB phenomenon, revealed mainly in pairs of low relative radial velocity separation and showing signs of interaction.Comment: A & A accepted, 6 pages, 6 figure

    Selection and micropropagation of valuable caper genotypes

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    The high quality of the various biotypes present in the natural or cultivated state is one of the main features for caper production. Up to now, however, no selection activity has been carried out in order to identify the most suitable accessions for providing better quality products. In this paper, we report the first results of a selection of caper genotypes characterised by significant qualitative traits. A micropropagation protocol was evaluated in order to improve and allow the multiplication of the most promising Capparis spinosa L. subsp. spinosa genotypes, selected in Salina (Aeolian Islands), Sicily (Italy), in collaboration with the most important local growers

    Studying the evolution of large-scale structure with the VIMOS-VLT Deep Survey

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    The VIMOS-VLT Deep Survey (VVDS) currently offers a unique combination of depth, angular size and number of measured galaxies among surveys of the distant Universe: ~ 11,000 spectra over 0.5 deg2 to I_{AB}=24 (VVDS-Deep), 35,000 spectra over ~ 7 deg2 to I_{AB}=22.5 (VVDS-Wide). The current ``First Epoch'' data from VVDS-Deep already allow investigations of galaxy clustering and its dependence on galaxy properties to be extended to redshifts ~1.2-1.5, in addition to measuring accurately evolution in the properties of galaxies up to z~4. This paper concentrates on the main results obtained so far on galaxy clustering. Overall, L* galaxies at z~ 1.5 show a correlation length r_0=3.6\pm 0.7. As a consequence, the linear galaxy bias at fixed luminosity rises over the same range from the value b~1 measured locally, to b=1.5 +/- 0.1. The interplay of galaxy and structure evolution in producing this observation is discussed in some detail. Galaxy clustering is found to depend on galaxy luminosity also at z~ 1, but luminous galaxies at this redshift show a significantly steeper small-scale correlation function than their z=0 counterparts. Finally, red galaxies remain more clustered than blue galaxies out to similar redshifts, with a nearly constant relative bias among the two classes, b_{rel}~1.4, despite the rather dramatic evolution of the color-density relation over the same redshift range.Comment: 14 pages. Extended, combined version of two invited review papers presented at: 1) XXVIth Astrophysics Moriond Meeting: "From Dark Halos to Light", March 2006, proc. edited by L.Tresse, S. Maurogordato and J. Tran Thanh Van (Editions Frontieres); 2) Vulcano Workshop 2006 "Frontier Objects in Astrophysics and Particle Physics", May 2006, proc. edited by F. Giovannelli & G. Mannocchi, Italian Physical Society (Editrice Compositori, Bologna

    The Th17 axis in psoriatic disease : pathogenetic and therapeutic implications

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    Psoriasis and psoriatic arthritis represent two paradigmatic conditions characterized by chronic inflammation and possibly autoimmunity, despite the absence of known serum autoantibodies. The two diseases, albeit strongly correlated from clinical, genetic, and epidemiogical standpoints, manifest significant differences in terms of etiology and pathogenetic mechanisms. Nonetheless, Th17 cells appear crucial to both diseases, and IL23 is the cytokine involved in determining the fate of naive CD4+ cells to differentiate into a pathogenic phenotype. This basic experimental observation led to a clear understanding of the immune dysfunction causing psoriasis and psoriatic arthritis but, more importantly, also led to new therapeutic approaches. In recent years, monoclonal antibodies directed to IL12/IL23 (ustekinumab) or IL17 (secukinumab, ixekizumab, brodalumab) are being investigated or have proven to be beneficial for patients with psoriatic disease, thus further supporting the view that Th17 cells play a pivotal role in disease onset and perpetuation. These most recent reports indeed represent significant developments that may allow overcoming the TNF\u3b1 pathway as the major therapeutic target in chronic inflammation
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