337 research outputs found

    From spirals to lenticulars: evidence from the rotation curves and mass models of three early-type galaxies

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    Rotation curves have traditionally been difficult to trace for early-type galaxies (ETGs) because they often lack a high-density disk of cold gas as in late-type galaxies (LTGs). We derive rotation curves for three lenticular galaxies from the ATLAS3D survey, combining CO data in the inner parts with deep HI data in the outer regions, extending out to 10-20 effective radii. We also use Spitzer photometry at 3.6 um to decompose the rotation curves into the contributions of baryons and dark matter (DM). We find that (1) the rotation-curve shapes of these ETGs are similar to those of LTGs of similar mass and surface brightness; (2) the dynamically-inferred stellar mass-to-light ratios are small for quiescent ETGs but similar to those of star-forming LTGs; (3) the DM halos follow the same scaling relations with galaxy luminosity as those of LTGs; (4) one galaxy (NGC 3626) is poorly fitted by cuspy DM profiles, suggesting that DM cores may exist in high-mass galaxies too. Our results indicate that these lenticular galaxies have recently transitioned from LTGs to ETGs without altering their DM halo structure (e.g., via a major merger) and could be faded spirals. We also confirm that ETGs follow the same radial acceleration relation as LTGs, reinforcing the notion that this is a universal law for all galaxy types.Comment: Accepted for publication in A&

    A promising new ELISA diagnostic test for cattle babesiosis based on Babesia bigemina Apical Membrane Antigen-1.

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    Babesiosis due to Babesia bigemina is a relevant tick‑borne disease, affecting cattle worldwide. Many surface proteins of the pathogen including the Apical Membrane Antigen 1 (AMA‑1) ‑ have been analysed for vaccine and diagnostic purposes. This study focused on B. bigemina AMA‑1 and on its use for the assessment of diagnostic tests. After bioinformatic analyses, AMA‑1 codifying region was amplified and cloned into an expression vector used to induce protein synthesis in Escherichia coli cells. AMA‑1 was purified by affinity chromatography and used to set up the best condition for an ELISA protocol. Bovine field sera positive to B. bigemina were used to evaluate the presence of anti‑AMA‑1 antibodies. In order to verify the assay specificity, sera positive to Babesia bovis or to the piroplasm Theileria annulata were also included. Significant differences were obtained between sera negative to both B. bigemina and B. bovis and samples positive to B. bigemina, to B. bovis or to both pathogens. No significant reaction was observed with T. annulata positive sera. The results showed that AMA‑1 protein is suitable to be used as antigen in diagnostic assays for babesiosis diagnosis in cattle, as it does not show any cross reaction with anti-T. annulata antibodies

    Microbiological and serological monitoring in hooded crow (Corvus corone cornix) in the Region Lombardia, Italy

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    The health status of 276 hooded crows (Corvus corone cornix) from various provinces of Lombardy was monitored for three years. Bacteriological examination detected E. coli (76%), Campylobacter jejuni (17%), Salmonella typhimurium (11.6%), Yersinia spp. (6.5%), Clamydophila abortus and C. psittaci (2.6%); from six birds showing severe prostration Pasteurella multocida was isolated. Virological and serological tests were negative for Avian Influenza virus (AIV), West Nile virus (WNV) and only three samples were positive for Newcastle disease virus (NDV) but only at serology (titre 1:16)

    Overcoming Language Dichotomies: Toward Effective Program Comprehension for Mobile App Development

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    Mobile devices and platforms have become an established target for modern software developers due to performant hardware and a large and growing user base numbering in the billions. Despite their popularity, the software development process for mobile apps comes with a set of unique, domain-specific challenges rooted in program comprehension. Many of these challenges stem from developer difficulties in reasoning about different representations of a program, a phenomenon we define as a "language dichotomy". In this paper, we reflect upon the various language dichotomies that contribute to open problems in program comprehension and development for mobile apps. Furthermore, to help guide the research community towards effective solutions for these problems, we provide a roadmap of directions for future work.Comment: Invited Keynote Paper for the 26th IEEE/ACM International Conference on Program Comprehension (ICPC'18

    Malin 1: interacting galaxy pair?

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    Malin 1 is a unique, extraordinarily large low surface brightness galaxy. The structure and the origins of the galaxy are poorly understood. The reason for such a situation is an absence of detailed observational data, especially, of high-resolution kinematics. In this Letter we study the stellar kinematics of the inner part (r < 15 kpc) of Malin 1. We present spectroscopic arguments in favour of a small galaxy - Malin 1B - being a companion probably interacting with the main galaxy - Malin 1. This object is clearly seen in many published images of Malin 1 but is not mentioned in any astronomical databases. Malin 1B is located at the projected distance of 14 kpc from the Malin 1's nucleus and has small - 65±\pm16 km/s - relative velocity, which we determined for the first time. We suggest that ongoing interaction with Malin 1B can explain main morphological features of the Malin 1's central region - two-armed spiral structure, a bar, and an external one-armed spiral pattern. We also investigated the large scale environment of Malin 1 and postulate that the galaxy SDSS J123708.91+142253.2 might be responsible for the formation of extended low-surface brightness envelope by means of head-on collision with Malin 1 (in the framework of collision scenario proposed by Mapelli et al. 2008). To test the collisional origins of Malin 1 global structure, more observational data and new numerical models are needed.Comment: 5 pages, 4 figures, accepted for publication in MNRA

    Molecular gas and star formation in the Tidal Dwarf Galaxy VCC 2062

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    The final, definitive version of this paper has been published in A&A, Vol 590, A92, June 2016, doi: 10.1051/0004-6361/201527887. Reproduced with permission from Astronomy & Astrophysics, © ESO.The physical mechanisms driving star formation (SF) in galaxies are still not fully understood. Tidal dwarf galaxies (TDGs), made of gas ejected during galaxy interactions, seem to be devoid of dark matter and have a near-solar metallicity. The latter makes it possible to study molecular gas and its link to SF using standard tracers (CO, dust) in a peculiar environment. We present a detailed study of a nearby TDG in the Virgo Cluster, VCC 2062, using new high-resolution CO(1--0) data from the Plateau de Bure, deep optical imaging from the Next Generation Virgo Cluster Survey (NGVS), and complementary multiwavelength data. Until now, there was some doubt whether VCC 2062 was a true TDG, but the new deep optical images from the NGVS reveal a stellar bridge between VCC 2062 and its parent galaxy, NGC 4694, which is clear proof of its tidal origin. Several high-resolution tracers (\halpha, UV, 8~\mi, and 24~\mi) of the star formation rate (SFR) are compared to the molecular gas distribution as traced by the CO(1-0). Coupled with the SFR tracers, the NGVS data are used with the CIGALE code to model the stellar populations throughout VCC 2062, yielding a declining SFR in the recent past, consistent with the low \halpha/UV ratio, and a high burst strength. HI emission covers VCC 2062, whereas the CO is concentrated near the HI maxima. The CO peaks correspond to two very distinct regions: one with moderate SF to the NE and one with only slightly weaker CO emission but with nearly no SF. Even where SF is clearly present, the SFR is below the value expected from the surface density of the molecular and the total gas as compared to spiral galaxies and other TDGs. After discussing different possible explanations, we conclude that the low surface brightness is a crucial parameter to understand the low SFR.Peer reviewe

    Epiphytic lichens of the sacred natural site &quot;Bosco di Sant&apos;Antonio&quot; (Majella National Park - Abruzzo)

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    Sacred Natural Sites are relevant for biodiversity conservation, as in the case of forest sites that, across centuries, developed old growth structures and are now crucial for the conservation of epiphytic lichens and other specialized forest organisms. In this study, we investigated the epiphytic lichen flora of a small forest patch included in the Majella National Park (Abruzzo), whose old growth features and naturalness reflect its long lasting spiritual role that perfectly fits with the concept of Sacred Natural Site. Results revealed that the "Bosco di Sant'Antonio" hosts a rich and interesting epiphytic lichen flora, thus indicating the potential of this Sacred Natural Site for lichen conservation. Fifty-six species were found including two species newly recorded in Abruzzo, two red-listed species, and the sensitive species Lobaria pulmonaria. This study corroborates the hypothesis that sacred forest sites are relevant for the conservation of specialized epiphytic lichens. In particular, in the Italian forest landscape where old-growth stands are practically absent, sacred forest sites may provide unique old-growth structures and buffer anthropogenic disturbance

    Torque Teno Sus Virus (TTSuV) Prevalence in Wild Fauna of Northern Italy

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    Torque teno sus virus (TTSuV) is a non-enveloped circular ssDNA virus which frequently infects swine and has been associated with hepatic, respiratory, and autoimmune disorders. TTSuV’s pathogenic role is still uncertain, and clear data in the literature on virus reservoirs are lacking. The aims of this study were to investigate the presence of potentially zoonotic TTSuV in wild animals in Northern Italy and to evaluate their role as reservoirs. Liver samples were collected between 2016 and 2020 during four hunting seasons from wild boars (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), and chamois (Rupicapra rupicapra). Samples originated from areas in Northern Italy characterized by different traits, i.e., mountains and flatland with, respectively low and high farm density and anthropization. Viral identification was carried out by end-point PCR with specific primers for TTSuV1a and TTSuVk2a species. TTSuV prevalence in wild boars was higher in the mountains than in the flatland (prevalence of 6.2% and 2.3%, respectively). In wild ruminants only TTSuVk2a was detected (with a prevalence of 9.4%). Our findings shed light on the occurrence and distribution of TTSuV in some wild animal species, investigating their possible role as reservoirs

    Inertial control of the mirror suspensions of the VIRGO interferometer for gravitational wave detection

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    In order to achieve full detection sensitivity at low frequencies, the mirrors of interferometric gravitational wave detectors must be isolated from seismic noise. The VIRGO vibration isolator, called 'superattenuator', is fully effective at frequencies above 4 Hz. Nevertheless, the residual motion of the mirror at the mechanical resonant frequencies of the system are too large for the interferometer locking system and must be damped. A multidimensional feedback system, using inertial sensors and digital processing, has been designed for this purpose. An experimental procedure for determining the feedback control of the system has been defined. In this paper a full description of the system is given and experimental results are presented.Comment: 17 pages, 11 figures, accepted for publication on Review of Scientific Instrument
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