407 research outputs found

    Paleoecology and paleobiogeography of fossil mollusks from Isabela

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    The Gaia spectrophotometric standard stars survey -II. Instrumental effects of six ground-based observing campaigns

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    The Gaia SpectroPhotometric Standard Stars (SPSS) survey started in 2006, it was awarded almost 450 observing nights, and accumulated almost 100,000 raw data frames, with both photometric and spectroscopic observations. Such large observational effort requires careful, homogeneous, and automated data reduction and quality control procedures. In this paper, we quantitatively evaluate instrumental effects that might have a significant (i.e.,≥\geq1%) impact on the Gaia SPSS flux calibration. The measurements involve six different instruments, monitored over the eight years of observations dedicated to the Gaia flux standards campaigns: DOLORES@TNG in La Palma, EFOSC2@NTT and ROSS@REM in La Silla, [email protected] in Calar Alto, BFOSC@Cassini in Loiano, and [email protected] in San Pedro Martir. We examine and quantitatively evaluate the following effects: CCD linearity and shutter times, calibration frames stability, lamp flexures, second order contamination, light polarization, and fringing. We present methods to correct for the relevant effects, which can be applied to a wide range of observational projects at similar instruments.Comment: 16 pages, 13 figures, accepted for publication in Astron. Nach

    Novel yttrium and zirconium catalysts featuring reduced Ar-BIANH2 ligands for olefin hydroamination (Ar-BIANH2 = bis-arylaminoacenaphthylene)

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    The novel class of bis-arylaminoacenaphthylenes (Ar-BIANH(2)) was employed for the preparation of zirconium and yttrium complexes to be used as catalysts for cyclohydroamination of a number of primary and secondary aminoalkenes. The complex [(2,6-iPr(2)C(6)H(3)-BIAN)Zr(NMe2)(2)(eta(1)-NHMe2)] was isolated and completely characterized, including X-ray diffraction analysis. Despite its easy and almost quantitative isolation, it showed only moderate catalytic performance in the intramolecular hydroamination, irrespective of the cyclization precursor used. On the other hand, in situ generated Y-III complexes obtained using the same class of ligands were found to be very active, leading to the hydroamination of substrates including those normally reluctant in undergoing cyclization such as those featuring an internal non-activated C=C double bond. Electron donating substituents and especially steric hindrance on the ligand improve the performance of the catalysts, allowing us to decrease the catalyst loading to 1 mol% in the latter case

    Geomorphologic Map of Northeastern Sector of San Jorge Gulf (Chubut, Argentina)

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    This paper presents a 1:100,000 scale geomorphologic map of the Northeastern sector of San Jorge Gulf (Chubut Province) in Patagonia, Argentina, covering more than 1,000 km2. Derived from remote sensing data and validated by three field surveys, it has been compiled in order to understand the past and recent evolution of the area with particular reference to sea-level oscillation studies, for which this map is the basic tool. The very low human impact and rates of dynamic landscape change allow the preservation of extensive palaeo deposits and landforms, including those indicative of sea-level variations. The relative change of sea level dominates landscape evolution, allowing the formation of widespread marine and lagoon deposits often interfingering with fluvial deposits and reworked by aeolian process in the framework of consequent beach progradation

    Gaia data release 1: Principles of the photometric calibration of the G band

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    Context. Gaia is an ESA cornerstone mission launched on 19 December 2013 aiming to obtain the most complete and precise 3D map of our Galaxy by observing more than one billion sources. This paper is part of a series of documents explaining the data processing and its results for Gaia Data Release 1, focussing on the G band photometry. Aims. This paper describes the calibration model of the Gaia photometric passband for Gaia Data Release 1. Methods. The overall principle of splitting the process into internal and external calibrations is outlined. In the internal calibration, a self-consistent photometric system is generated. Then, the external calibration provides the link to the absolute photometric flux scales. Results. The Gaia photometric calibration pipeline explained here was applied to the first data release with good results. Details are given of the various calibration elements including the mathematical formulation of the models used and of the extraction and preparation of the required input parameters (e.g. colour terms). The external calibration in this first release provides the absolute zero point and photometric transformations from the Gaia G passband to other common photometric systems. Conclusions. This paper describes the photometric calibration implemented for the first Gaia data release and the instrumental effects taken into account. For this first release no aperture losses, radiation damage, and other second-order effects have not yet been implemented in the calibration.Comment: 15 pages, 16 figures, Gaia data release 1 documentation special volum

    Real life use of bendamustine in elderly patients with lymphoid neoplasia

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    Background. Bendamustine is a cytotoxic alkylating drug with a broad range of indications as a single agent or in combination therapy in lymphoid neoplasia patients. However, its tolerability in elderly patients is still debated. Methods: An observational, retrospective study was carried out; patients with chronic lymphocytic leukemia (CLL) or lymphoma, aged ≥ 65 years old, treated with bendamustine-based regimens in first or subsequent lines between 2010 and 2020 were considered eligible. Results: Overall, 179 patients aged ≥ 65 years were enrolled, 53% between 71 and 79 years old. Cumulative Illness Rating Scale (CIRS) comorbidity score was ≥6 in 54% patients. Overall survival (OS) at 12 months was 95% (95% confidence interval [CI]: 90–97%); after a median follow up of 50 months, median OS was 84 months. The overall response rate was 87%, with 56% complete responses; the median time to progression (TTP) was 61 months. The baseline factors affecting OS by multivariable analysis were sex, histological diagnosis, renal function, and planned bendamustine dose, while only type of lymphoma and bendamustine dose impacted on TTP. Main adverse events were neutropenia (grade ≥ 3: 43%) and infections (any grade: 36%), with 17% of patients requiring hospital admission. Conclusions: The responses to bendamustine, as well as survival, are relevant even in advanced age patients, with a manageable incidence of acute toxicity
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