67 research outputs found

    Modeling the Galactic center gamma-ray emission with more realistic cosmic-ray dynamics

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    Very-high-energy gamma-ray observations of the Galactic center (GC) show extended emission that is strongly correlated with the morphology of the central molecular zone (CMZ). The best explanation for that emission is a hadronic interaction between cosmic rays (CRs) and ambient gas, where a CR central and continuous source accelerates protons up to 1 PeV ("PeVatron"). However, current models assume very simplistic CR dynamics. Our goal is to verify if more realistic CR dynamics for the GC environment are consistent with current gamma-ray observations, and whether they could be constrained by upcoming observations with the Cherenkov Telescope Array (CTA). We generated synthetic gamma-ray maps using a CR transport model with spherical injection, different diffusion regimes (in and out of the CMZ), polar advection, and mono-energetic particles of 1 PeV, and including different CR populations injected from the Arches, Quintuplet, and nuclear clusters of young massive stars, plus supernova Sgr A East. We adopted two different 3D gas distributions consistent with the observed gas column density, either with or without an inner cavity. In order to reproduce the existing observations detected by the High Energy Stereoscopic System (HESS), a ring-like gas distribution, with its mass set by the standard Galactic CO-to-H2_2 conversion factor, and CR acceleration from all relevant sources are required. For a conversion factor one order of magnitude lower, injection rates that are ten times higher are needed. We show that CTA will be able to differentiate between models with different CR dynamics, proton sources, and CMZ morphology, owing to its unprecedented sensitivity and angular resolution. More realistic CR dynamics suggest that the CMZ has a large inner cavity and that the GC PeVatron is a composite CR population accelerated by the Arches, Quintuplet, and nuclear star clusters, and Sgr A East.Comment: Accepted for publication in A&A. 15 pages, 11 figure

    Liquid biopsy for improving diagnosis and monitoring of CNS lymphomas:A RANO review

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    BACKGROUND: The utility of liquid biopsies is well documented in several extracranial and intracranial (brain/leptomeningeal metastases, gliomas) tumors. METHODS: The RANO (Response Assessment in Neuro-Oncology) group has set up a multidisciplinary Task Force to critically review the role of blood and cerebrospinal fluid (CSF)-liquid biopsy in CNS lymphomas, with a main focus on primary central nervous system lymphomas (PCNSL). RESULTS: Several clinical applications are suggested: diagnosis of PCNSL in critical settings (elderly or frail patients, deep locations, and steroid responsiveness), definition of minimal residual disease, early indication of tumor response or relapse following treatments, and prediction of outcome. CONCLUSIONS: Thus far, no clinically validated circulating biomarkers for managing both primary and secondary CNS lymphomas exist. There is need of standardization of biofluid collection, choice of analytes, and type of technique to perform the molecular analysis. The various assays should be evaluated through well-organized central testing within clinical trials.</p

    TRY plant trait database – enhanced coverage and open access

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    Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Galactic center gamma-ray production by cosmic rays from stellar winds and Sgr A East

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    Context. The High Energy Stereoscopic System, the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope, and the Very Energetic Radiation Imaging Telescope Array System have observed diffuse gamma-ray emission strongly correlated with the central molecular zone in the Galactic center. The most accepted scenario to generate this emission is via a hadronic interaction between cosmic rays (CRs) and ambient gas, where CRs are accelerated from a central and continuous source of 1 PeV protons. Aims. We explore the influence of the three-dimensional (3D) shape of the central molecular zone on the indirect observation of the CR energy density via gamma-ray detection. Methods. We simulated synthetic gamma-ray maps using a CR diffusion model with spherical injection, one isotropic diffusion coefficient, no advection, and mono-energetic particles of 1 PeV. Also, we used two different 3D gas distributions considering the observed gas column density, both with and without an inner cavity. Results. We find that when using a persistent CR source, a disk-like gas distribution is needed to reproduce the existing CR indirect observations. This is in agreement with the continuous gas distribution implied by some dynamical models and studies based on the comparison of emission and absorption molecular lines. However, it contradicts several models of the central molecular zone, which imply that this structure has a significant inner cavity. This tension can be reconciled by an additional, impulsive CR injection. Conclusions. If the central molecular zone has a cavity, a composite CR population, coming from the stellar winds of the Wolf-Rayet stars in the central 0.5 pc and the supernova Sgr A East, produces a good match to the observed gamma-ray morphology in the Galactic center

    Prevalence of anxiety in patients admitted to a university hospital in southern Brazil and associated factors

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    Objective: To identify the prevalence of anxiety in adults hospitalized in the clinical ward of a university hospital and to analyze the possible associated factors. Method: A cross-sectional study was performed in a university hospital. All interviewees answered a specific questionnaire and the Hospital Anxiety and Depression Scale. A Poisson regression was used to calculate prevalence ratios with 95% confidence intervals. Results: 282 patients were enrolled. The prevalence of anxiety was 33.7% (95%CI 28.2 - 39.3). Characteristics associated with the outcome were female gender (RP 2.44), age &#8805; 60 years (PR 0.65), consultation in primary health care (PR 2.37), estimated time of contact between patient and student > 30 min (RP 1.36), high blood pressure (PR 1.57), diabetes mellitus (PR 1.43), and obesity (RP 1.43). Conclusion: This study found prevalence of high anxiety. It may be associated with certain characteristics of the patients (gender, age, chronic diseases); the medical appointment in primary care and time (estimated by the patient) that the student remained with this patient. The need for a focused approach to mental health care within the hospital has been discussed for a long time. The particularity of this study refers to the environment of a university hospital and to what extent the environment and the patient's relationship with the student are associated with higher prevalence of anxiety

    Hydrothermal activity within a sedimentary succession: aragonites as indicators of Mesozoic Rifting (Iberian Basin, Spain)

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    Pseudo-hexagonal aragonite crystals occur profusely at various locations within the Upper Triassic sequences in Europe, America and Africa. In the Spanish Iberian Basin, they are associated with corrensite and gypsum, which characterize saline mudflat and salt-pond facies. Similarly, shaped crystals occur as dolomite, quartz, chalcedony or even copper pseudomorphs after aragonite in several parts of North and South America, and they are currently forming in association with hydrothermal spring deposits in Kenya. In Spain, this aragonite was first described at Molina de AragĂłn (Spain). Its origin has previously been explained as resulting from burial diagenetic processes, although petrographical, geochemical, stable isotope, and fluid inclusion evidence suggest a formation in other conditions. The aragonite crystals occur dominantly at locations near outcrops of pre-Hettangian alkaline magmatism, along Middle-to-Late Jurassic NW-SE faults. The formation of these aragonite crystals is interpreted as the result of upwards flow of hydrothermal fluids through the Middle-to-Late Jurassic synrift faults and the interaction with infiltrated shallow marine water. This hydrothermal circulation caused also the transformation of Mg-rich clay into corrensite. The pseudomorphs after aragonite found in other areas of the world appear related to sequences of similar depositional environments and interaction of magmatic intrusions within rifting settings. Such aragonite crystals may therefore help to unravel the geological and tectonic history in their area of occurrence

    Detecting implicit expressions of affect in text using EmotiNet and its extensions

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    In the past years, an important volume of research in Natural Language Processing has concentrated on the development of automatic systems to deal with affect in text. The different approaches considered dealt mostly with explicit expressions of emotion, at word level. Nevertheless, expressions of emotion are often implicit, inferrable from situations that have an affective meaning. Dealing with this phenomenon requires automatic systems to have “knowledge” on the situation, and the concepts it describes and their interaction, to be able to “judge” it, in the same manner as a person would. This necessity motivated us to develop the EmotiNet knowledge base — a resource for the detection of emotion from text based on commonsense knowledge on concepts, their interaction and their affective consequence. In this article, we briefly present the process undergone to build EmotiNet and subsequently propose methods to extend the knowledge it contains. We further on analyse the performance of implicit affect detection using this resource. We compare the results obtained with EmotiNet to the use of alternative methods for affect detection. Following the evaluations, we conclude that the structure and content of EmotiNet are appropriate to address the automatic treatment of implicitly expressed affect, that the knowledge it contains can be easily extended and that overall, methods employing EmotiNet obtain better results than traditional emotion detection approaches.The work of the authors affiliated to the Department of Software and Computing Systems at the University of Alicante has been supported by the Spanish Ministry of Science and Innovation (grant no. TIN2009-13391-C04-01), by the Spanish Ministry of Education under the FPU Program (AP2007-03076), and by the Valencian Ministry of Education (grant no. PROMETEO/2009/119 and ACOMP/2010/288)

    Topographic and hydrological controls on Subglacial Lake Ellsworth, West Antarctica

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    Subglacial Lake Ellsworth (SLE) was identified using reconnaissance data collected in the 1970s, here we present more detailed surveys. SLE lies beneath 3.2 km of ice in a subglacial valley in West Antarctica. It has an area of only similar to 18 km(2), is dissimilar to the large tectonically-controlled lakes beneath East Antarctica and is a strong candidate for in situ exploration. Our analysis indicates that the ice above SLE is floating on a fluid whose density is 950-1013 kg m(-3). This could indicate freshwater, but certainly precludes seawater, or high salt, acid, or clathrate content. The water in the lake is unlikely to be produced solely by local melt; it is more likely delivered via subglacial drainage. Our surveys show no identifiable hydrological barrier to outflow, meaning SLE is effectively full; new water entering the lake is likely balanced by outflow, which would drain into another lake that we have also identified
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