1,366 research outputs found

    Gaia Data Release 1. Cross-match with external catalogues - Algorithm and results

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    Although the Gaia catalogue on its own will be a very powerful tool, it is the combination of this highly accurate archive with other archives that will truly open up amazing possibilities for astronomical research. The advanced interoperation of archives is based on cross-matching, leaving the user with the feeling of working with one single data archive. The data retrieval should work not only across data archives, but also across wavelength domains. The first step for seamless data access is the computation of the cross-match between Gaia and external surveys. The matching of astronomical catalogues is a complex and challenging problem both scientifically and technologically (especially when matching large surveys like Gaia). We describe the cross-match algorithm used to pre-compute the match of Gaia Data Release 1 (DR1) with a selected list of large publicly available optical and IR surveys. The overall principles of the adopted cross-match algorithm are outlined. Details are given on the developed algorithm, including the methods used to account for position errors, proper motions, and environment; to define the neighbours; and to define the figure of merit used to select the most probable counterpart. Statistics on the results are also given. The results of the cross-match are part of the official Gaia DR1 catalogue.Comment: 18 pages, 8 figures. Accepted for publication by A&

    Intramedullary craniovertebral junction metastasis leading to the diagnosis of underlying renal cell carcinoma

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    Background: Intramedullary spinal cord metastases represent 4–8.5% of the central nervous system metastases and affect only 0.1–0.4% of all patients. Those originating from renal cell carcinoma (RCC) are extremely rare. Of the eight patients described in the literature with metastatic RCC and intramedullary cord lesion, only five were found in the cervical spine. Here, the authors add a 6th case involving an RCC intramedullary metastasis at the C1–C2 level. Case Description: A 78-year-old male patient presented with intermittent cervicalgia of 5 months duration accompanied by few weeks of a progressive severe right hemiparesis, up to hemiplegia. The magnetic resonance imaging (MRI) examination revealed an intramedullary expansive lesion measuring 10 mm×15 mm at the C1–C2 level; it readily enhanced with contrast. A total body computed tomography (CT) scan documented an 85 mm mass involving the right kidney, extending to the ipsilateral adrenal gland, and posteriorly infiltrating the ipsilateral psoas muscle. The subsequent CT-guided fine-needle biopsy confirmed the diagnosis of an RCC (Stage IV). The patient next underwent total surgical total removal of the C1–C2 intramedullary mass, following which he exhibited a slight motor improvement, with the right hemiparesis (2/5). He died after 14 months due to global RCC tumor progression. Conclusion: The present case highlights that a patient without a prior known diagnosis of RCC may present with an intramedullary C1–C2 metastasis. In such cases, global staging is critical to determine whether primary lesion resection versus excision of metastases (e.g., in this case, the C1–C2 intramedullary tumor) are warrante

    Studying the evolution of AGB stars in the Gaia epoch

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    We present asymptotic giant branch (AGB) models of solar metallicity, to allow the interpretation of observations of Galactic AGB stars, whose distances should be soon available after the first release of the Gaia catalogue. We find an abrupt change in the AGB physical and chemical properties, occurring at the threshold mass to ignite hot bottom burning,i.e. 3.5M⊙3.5M_{\odot}. Stars with mass below 3.5M⊙3.5 M_{\odot} reach the C-star stage and eject into the interstellar medium gas enriched in carbon , nitrogen and 17O^{17}O. The higher mass counterparts evolve at large luminosities, between 3×104L⊙3\times 10^4 L_{\odot} and 105L⊙10^5 L_{\odot}. The mass expelled from the massive AGB stars shows the imprinting of proton-capture nucleosynthesis, with considerable production of nitrogen and sodium and destruction of 12C^{12}C and 18O^{18}O. The comparison with the most recent results from other research groups are discussed, to evaluate the robustness of the present findings. Finally, we compare the models with recent observations of galactic AGB stars, outlining the possibility offered by Gaia to shed new light on the evolution properties of this class of objects.Comment: 21 pages, 11 figure, 3 tables, accepted for publication in MNRAS (2016 July 11

    A robust ransac-based planet radius estimation for onboard visual based navigation

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    Individual spacecraft manual navigation by human operators from ground station is expected to be an emerging problem as the number of spacecraft for space exploration increases. Hence, as an attempt to reduce the burden to control multiple spacecraft, future missions will employ smart spacecraft able to navigate and operate autonomously. Recently, image-based optical navigation systems have proved to be promising solutions for inexpensive autonomous navigation. In this paper, we propose a robust image processing pipeline for estimating the center and radius of planets and moons in an image taken by an on-board camera. Our custom image pre-processing pipeline is tailored for resource-constrained applications, as it features a computationally simple processing flow with a limited memory footprint. The core of the proposed pipeline is a best-fitting model based on the RANSAC algorithm that is able to handle images corrupted with Gaussian noise, image distortions, and frame drops. We report processing time, pixel-level error of estimated body center and radius and the effect of noise on estimated body parameters for a dataset of synthetic images

    Long-term bone outcomes in Italian patients with Gaucher disease type 1 or type 3 treated with imiglucerase: A sub-study from the International Collaborative Gaucher Group (ICGG) Gaucher Registry

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    Background: Gaucher disease (GD) is a lysosomal storage disorder. We evaluated the “real-world” effectiveness of first-line imiglucerase on long-term bone outcomes in Italian patients in the International Collaborative Gaucher Group (ICGG) Gaucher Registry. Methods: Patients treated with imiglucerase for ≥2 years and with bone assessments at baseline and during follow-up were selected. Data on bone pain, bone crises, marrow infiltration, avascular necrosis, infarction, lytic lesions, Erlenmeyer flask deformity, bone fractures, mineral density, and imiglucerase dosage were evaluated. Results: Data on bone manifestations were available for 73 of 229 patients (31.9 %). Bone crises frequency decreased significantly from baseline to the most recent follow-up (p < 0.001), with some improvement observed in bone pain prevalence. Bone pain and bone crises prevalence decreased significantly from baseline at 2 to <4 and 4 to <6 years (all p < 0.05). A low median (25th, 75th percentile) baseline imiglucerase dosage was identified in patients reporting bone pain or bone crises (15.0 [13.7, 30.0] and 22.8 [17.5, 36.0] U/kg once every 2 weeks, respectively). Conclusion: Our study suggests that the management of GD in Italy, with regards to imiglucerase dosage, is suboptimal and confirms the need for clinicians to monitor and correctly treat bone disease according to best practice guidelines

    CloudScout: A deep neural network for on-board cloud detection on hyperspectral images

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    The increasing demand for high-resolution hyperspectral images from nano and microsatellites conflicts with the strict bandwidth constraints for downlink transmission. A possible approach to mitigate this problem consists in reducing the amount of data to transmit to ground through on-board processing of hyperspectral images. In this paper, we propose a custom Convolutional Neural Network (CNN) deployed for a nanosatellite payload to select images eligible for transmission to ground, called CloudScout. The latter is installed on the Hyperscout-2, in the frame of the Phisat-1 ESA mission, which exploits a hyperspectral camera to classify cloud-covered images and clear ones. The images transmitted to ground are those that present less than 70% of cloudiness in a frame. We train and test the network against an extracted dataset from the Sentinel-2 mission, which was appropriately pre-processed to emulate the Hyperscout-2 hyperspectral sensor. On the test set we achieve 92% of accuracy with 1% of False Positives (FP). The Phisat-1 mission will start in 2020 and will operate for about 6 months. It represents the first in-orbit demonstration of Deep Neural Network (DNN) for data processing on the edge. The innovation aspect of our work concerns not only cloud detection but in general low power, low latency, and embedded applications. Our work should enable a new era of edge applications and enhance remote sensing applications directly on-board satellite

    BEHAVIOUR OF Aeromonas hydrophila IN SALTED SWORDFISH SAMPLES

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    A challenge test for Aeromonas hydrophila in salted swordfish samples was carried out. Particularly, 24 samples (250g) were experimentally contaminated, salted and stored at two different temperature regimes (fluctuating – F group - and non fluctuating – NF group – regime). The count of A. hydrophila, Enterobacteria and Lactic acid bacteria (LAB) as well as the determination of pH and aw were performed at 0, 19 43, 163, 187, 230, 320 and 368 hours whereas the temperature was monitored continuously by using 6 data-loggers. In both group, the mean concentrations of A. hydrophila did not exceed Log 3 cfu/g and decreased below the mean value of Log 1 cfu/g after 368 hours. However in the F group the A. hydrophila growth was slower and the decrease appeared slightly higher than NF group and this suggests the temperature fluctuations induces a more pronounced behaviour variability of A. hydrophila under stressing conditions

    Donkey milk fermentation by lactococcus lactis subsp. Cremoris and lactobacillus rhamnosus affects the antiviral and antibacterial milk properties

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    Background: Milk is considered an important source of bioactive peptides, which can be produced by endogenous or starter bacteria, such as lactic acid bacteria, that are considered effective and safe producers of food-grade bioactive peptides. Among the various types of milk, donkey milk has been gaining more and more attention for its nutraceutical properties. Methods: Lactobacillus rhamnosus 17D10 and Lactococcus lactis subsp. cremoris 40FEL3 were selected for their ability to produce peptides from donkey milk. The endogenous peptides and those obtained after bacterial fermentation were assayed for their antioxidant, antibacterial, and antiviral activities. The peptide mixtures were characterized by means of LC-MS/MS and then analyzed in silico using the Milk Bioactive Peptide DataBase. Results: The peptides produced by the two selected bacteria enhanced the antioxidant activity and reduced E. coli growth. Only the peptides produced by L. rhamnosus 17D10 were able to reduce S. aureus growth. All the peptide mixtures were able to inhibit the replication of HSV-1 by more than 50%. Seventeen peptides were found to have 60% sequence similarity with already known bioactive peptides. Conclusions: A lactic acid bacterium fermentation process is able to enhance the value of donkey milk through bioactivities that are important for human health
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