Gaia Data Release 1 Carrasco, J M; Evans, D W; Montegriffo, P ...
Astronomy and astrophysics (Berlin),
11/2016, Letnik:
595
Journal Article
Recenzirano
Odprti dostop
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 GaiaG 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.
Roughening of Ti6Al4V by blasting with alumina or zirconia particles improves the mechanical fixation of implants by increasing the surface area available for bone/implant apposition. Additional ...thermal oxidation treatments of the blasted alloy have already shown to be a complementary low-cost solution to enhancing the in vitro biocompatibility and corrosion resistance of the alloy. In this work, the effects of oxidation treatment on a grit blasted Ti6Al4V biomedical alloy have been analysed in order to understand the net effect of the combined treatments on the alloy fatigue properties. Synchrotron radiation diffraction experiments have been performed to measure residual stresses before and after the treatments and microstructural and hardness changes have been determined. Although blasting of Ti6Al4V with small spherical zirconia particles increases the alloy fatigue resistance with respect to unblasted specimens, fatigue strength after oxidation decreases below the unblasted value, irrespective of the type of particle used for blasting. Moreover, at 700°C the as-blasted compressive residual stresses (700MPa) are not only fully relaxed but even moderate tensile residual stresses, of about 120MPa, are found beneath the blasted surfaces. Contrary to expectations, a moderate increase in hardness occurs towards the blasted surface after oxidation treatments. This can be attributed to the fact that grit blasting modifies the crystallographic texture of the Ti6Al4V shifting it to a random texture, which affects the hardness values as shown by additional experiments on cold rolled samples. The results indicate that the oxidation treatment performed to improve biocompatibility and corrosion resistance of grit blasted Ti6Al4V should be carried out with caution since the alloy fatigue strength can be critically diminished below the value required for high load-bearing components.
•Thermal oxidation of blasted Ti6Al4V induces critical microstructural changes.•Residual stress state changes from compressive to tensile at the subsurface.•Fatigue strength of blasted alloy decreases sharply after thermal oxidation.•Grit blasting modifies the crystallographic texture of the blasting affected zone.
A considerable body of research has recently emerged around nonmotor symptoms in Parkinson's disease (PD) and their substantial impact on patients' well-being. A prominent example is constipation ...which occurs in up to two thirds of all PD-patients thereby effecting psychological and social distress and consequently reducing quality of life. Despite the significant clinical relevance of constipation, unfortunately little knowledge exists on effective treatments. Therefore this systematic review aims at providing a synopsis on clinical effects and safety of available treatment options for constipation in PD. For this purpose, three electronic databases (MEDLINE, EMBASE, PsycINFO) were searched for experimental and quasi-experimental studies investigating the efficacy/effectiveness of interventions in the management of PD-associated constipation. Besides, adverse events were analyzed as secondary outcome. In total, 18 publications were identified involving 15 different interventions, of which none can be attributed sufficient evidence to derive strong recommendations. Nevertheless, some evidence indicates that dietetic interventions with probiotics and prebiotics may reduce symptom burden while providing a very favorable side-effects profile. Furthermore, the use of lubiprostone, macrogol and in the specific case of isolated or prominent outlet obstruction constipation injections of botulinum neurotoxin A into the puborectal muscles may as well be moderately supported. In summary, too little attention has been paid to treatment options for constipation in PD leaving abundant room for further research addressing this topic.
This research addresses the determination of residual stresses in sandblasted austenitic steel by ultramicroindentation techniques using a sharp indenter, of which the sensitivity to residual stress ...effects is said to be inferior to that of spherical ones. The introduction of an angular correction in the model of Wang et al. which relates variations in the maximum load to the presence of residual stresses is proposed. Similarly, the contribution to the hardness of grain size refinement and work hardening, developed as a consequence of the severe plastic deformation during blasting, is determined in order to avoid overestimation of the residual stresses. Measurements were performed on polished cross sections along a length of several microns, thus obtaining a profile of the residual stresses. Results show good agreement with those obtained by synchrotron radiation on the same specimens, which validates the method and demonstrates that microindentation using sharp indenters may be sensitive to the residual stress effect.
Research on heritage education has progressed remarkably and a large number of studies point to a greater presence of active methodologies and the use of resources and primary sources in the ...classroom. At this point it seems important to investigate the perceptions and experiences of future history and social science teachers. Thus, this paper studies the value that 506 Spanish and English teachers in initial training place on heritage and its presence in the teaching-learning process of history, as well as their views on the existing connections between methodological perceptions and the use of cultural heritage in the classroom. It is a non-experimental descriptive and quantitative study with data collected through questionnaire. This questionnaire was built ad hoc to analyze the opinions and perceptions of teachers in initial training about history education in Secondary Education. The results show that teachers in initial training value highly or very highly the use of cultural heritage in Secondary Education to promote active methodologies, the critical teaching of history, and the development of historical skills. Teachers in training in Spain value more highly the use of heritage than English teachers. While English teachers in training value more highly the resolution of problems through historical documentary sources, Spanish teachers rate the emotional and motivational aspects higher.
We show that the decoherence phenomena applied to the neutrino system could lead to an observable breaking of the fundamental CPT symmetry. We require specific textures of nondiagonal decoherence ...matrices, with nonzero δCP, for making such observations. Using the information from the CPT conjugate channels νμ→νμ and ν¯μ→ν¯μ and their corresponding backgrounds, we have estimated the sensitivity of the DUNE experiment for testing CPT under the previous conditions. Four scenarios for energy-dependent decoherence parameters, ΓEν=Γ×(Eν/GeV)n, n=−1, 0, 1, and 2, are taken into account, and for most of them, DUNE is able to achieve a 5σ discovery potential, having Γ in O(10−23 GeV) for δCP=3π/2. Meanwhile, for δCP=π/2, we reach 3σ for Γ in O(10−24 GeV).
Ionosonde data and crustal earthquakes with magnitude M≥6.0 observed in Greece during the 2003–2015 period were examined to check if the relationships obtained earlier between precursory ionospheric ...anomalies and earthquakes in Japan and central Italy are also valid for Greek earthquakes. The ionospheric anomalies are identified on the observed variations of the sporadic E-layer parameters (h′Es, foEs) and foF2 at the ionospheric station of Athens. The corresponding empirical relationships between the seismo-ionospheric disturbances and the earthquake magnitude and the epicentral distance are obtained and found to be similar to those previously published for other case studies. The large lead times found for the ionospheric anomalies occurrence may confirm a rather long earthquake preparation period. The possibility of using the relationships obtained for earthquake prediction is finally discussed. Keywords. Ionosphere (Ionospheric disturbances)
This work deals with the surface modification of 316LVM stainless steel by Si+ ion implantation and the in vitro study of its effect on the short-term corrosion behaviour and ion release. In order to ...achieve a high Si content close to the surface, the experimental set up was designed with different implantation doses, acceleration voltages and angles of incidence. Corrosion tests were carried out by Electrochemical Impedance Spectroscopy (EIS). A special feature of this paper is the evaluation of the EIS data obtained through a critical analysis of the existing equivalent electrical circuits, in order to establish adequate parameters and scientific criteria to propose a classification of the corrosion response of the investigated surfaces. It has been demonstrated that doses of Si+ ion implantation equal to 2.5 × 1016 ion/cm2 and an acceleration voltages of 50 keV enhanced the corrosion protection. In contrast, higher ion-implantation dose (1 × 1017 ion/cm2) and acceleration voltage (80 keV) produced worse results, probably due to the development of strain induced α’-martensite. The quantity of relevant ions (Cr, Fe, Mn, Mo, Ni and Si) released to the medium was determined by an optimized Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) method. It has been shown that a better corrosion resistance is accompanied by a reduction in the amount of ions released.
Display omitted
•Impedance measurements show that Si-ion implantation can enhance corrosion behaviour.•High doses of implantation might develop strain induced martensite.•The ICP-OES method has permitted an accurate analysis of Cr, Fe, Mn, Mo, Ni and Si.•A better corrosion resistance is accompanied of a lower amount of ions released.
We present a new transcriptome assembly of the Pacific whiteleg shrimp (Litopenaeus vannamei), the species most farmed for human consumption. Its functional annotation, a substantial improvement over ...previous ones, is provided freely. RNA-Seq with Illumina HiSeq technology was used to analyze samples extracted from shrimp abdominal muscle, hepatopancreas, gills and pleopods. We used the Trinity and Trinotate software suites for transcriptome assembly and annotation, respectively. The quality of this assembly and the affiliated targeted homology searches greatly enrich the curated transcripts currently available in public databases for this species. Comparison with the model arthropod Daphnia allows some insights into defining characteristics of decapod crustaceans. This large-scale gene discovery gives the broadest depth yet to the annotated transcriptome of this important species and should be of value to ongoing genomics and immunogenetic resistance studies in this shrimp of paramount global economic importance.
Mitochondrial DNA is a valuable taxonomic marker due to its relatively fast rate of evolution. In Trypanosoma cruzi, the causative agent of Chagas disease, the mitochondrial genome has a unique ...structural organization consisting of 20-50 maxicircles (∼20 kb) and thousands of minicircles (0.5-10 kb). T. cruzi is an early diverging protist displaying remarkable genetic heterogeneity and is recognized as a complex of six discrete typing units (DTUs). The majority of infected humans are asymptomatic for life while 30-35% develop potentially fatal cardiac and/or digestive syndromes. However, the relationship between specific clinical outcomes and T. cruzi genotype remains elusive. The availability of whole genome sequences has driven advances in high resolution genotyping techniques and re-invigorated interest in exploring the diversity present within the various DTUs.
To describe intra-DTU diversity, we developed a highly resolutive maxicircle multilocus sequence typing (mtMLST) scheme based on ten gene fragments. A panel of 32 TcI isolates was genotyped using the mtMLST scheme, GPI, mini-exon and 25 microsatellite loci. Comparison of nuclear and mitochondrial data revealed clearly incongruent phylogenetic histories among different geographical populations as well as major DTUs. In parallel, we exploited read depth data, generated by Illumina sequencing of the maxicircle genome from the TcI reference strain Sylvio X10/1, to provide the first evidence of mitochondrial heteroplasmy (heterogeneous mitochondrial genomes in an individual cell) in T. cruzi.
mtMLST provides a powerful approach to genotyping at the sub-DTU level. This strategy will facilitate attempts to resolve phenotypic variation in T. cruzi and to address epidemiologically important hypotheses in conjunction with intensive spatio-temporal sampling. The observations of both general and specific incidences of nuclear-mitochondrial phylogenetic incongruence indicate that genetic recombination is geographically widespread and continues to influence the natural population structure of TcI, a conclusion which challenges the traditional paradigm of clonality in T. cruzi.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
