8 research outputs found
A Grid of Synthetic Stellar UV Fluxes
We present preliminary results of a large project aimed at creating an
extended theoretical and observational database of stellar spectra in the
ultraviolet wavelength range. This library will consist of IUE spectra at low
and high resolution, and a set of LTE and NLTE theoretical fluxes. A first grid
of 50 model fluxes with solar metallicity, in the wavelength interval 1000 -
4400 AA, is reported here. Calculations are based on the Kurucz (1993) SYNTHE
code. The models span effective temperatures between 10,000 K and 50,000 K, and
a surface gravity in the range 2.5 <= log g <= 5.0 dex.Comment: 2 pages, 1 figure, To appear in proceedings, "New Quests in Stellar
Astrophysics: The Link Between Stars and Cosmology ", March 26-30, 2001, Eds.
M. Chavez, A. Bressan, A. Buzzoni & D. Mayy
Statistical Properties of the GALEX/SDSS matched source catalogs, and classification of the UV sources
We use the Galaxy Evolution Explorer (GALEX) Medium and All-Sky-Imaging
Survey (MIS & AIS) data from the first public data release (GR1), matched to
the Sloan Digital Sky Survey (SDSS) DR3 catalog, to perform source
classification. The GALEX surveys provide photometry in far- and near-UV bands
and the SDSS in five optical bands (u,g,r,i,z). The GR1/DR3 overlapping areas
are 363[83]deg^2 for the GALEX AIS[MIS], for sources within the 0.5deg central
area of the GALEX fields. Our sample covers mostly |b|>30deg galactic
latitudes. We present statistical properties of the GALEX/SDSS matched sources
catalog, containing >2x10^6 objects detected in at least one UV band. We
classify the matched sources by comparing the seven-band photometry to model
colors constructed for different classes of astrophysical objects. For sources
with photometric errors <0.3 mag, the corresponding typical AB-magnitude limits
are m_FUV~21.5, m_NUV~22.5 for AIS, and m_FUV~24, m_NUV~24.5 for MIS. At AIS
depth, the number of Galactic and extragalactic objects are comparable, but the
latter predominate in the MIS. Based on our stellar models, we estimate the
GALEX surveys detect hot White Dwarfs throughout the Milky Way halo (down to a
radius of 0.04 R_sun at MIS depth), providing an unprecedented improvement in
the Galactic WD census. Their observed surface density is consistent with Milky
Way model predictions. We also select low-redshift QSO candidates, extending
the known QSO samples to lower magnitudes, and providing candidates for
detailed z~1 follow-up investigations. SDSS optical spectra available for a
large subsample confirm the classification for the photometrically selected
candidates with 97% purity for single hot stars, ~45%(AIS)/31%(MIS) for
binaries containing a hot star and a cooler companion, and about 85% for QSOs.Comment: 33 pages, 11 figures, accepted for the GALEX special issue of ApJS.
For a version with full resolution figures see
http://dolomiti.pha.jhu.edu/publgoto.htm
Measurement of the Z/gamma* + b-jet cross section in pp collisions at 7 TeV
The production of b jets in association with a Z/gamma* boson is studied
using proton-proton collisions delivered by the LHC at a centre-of-mass energy
of 7 TeV and recorded by the CMS detector. The inclusive cross section for
Z/gamma* + b-jet production is measured in a sample corresponding to an
integrated luminosity of 2.2 inverse femtobarns. The Z/gamma* + b-jet cross
section with Z/gamma* to ll (where ll = ee or mu mu) for events with the
invariant mass 60 < M(ll) < 120 GeV, at least one b jet at the hadron level
with pT > 25 GeV and abs(eta) < 2.1, and a separation between the leptons and
the jets of Delta R > 0.5 is found to be 5.84 +/- 0.08 (stat.) +/- 0.72 (syst.)
+(0.25)/-(0.55) (theory) pb. The kinematic properties of the events are also
studied and found to be in agreement with the predictions made by the MadGraph
event generator with the parton shower and the hadronisation performed by
PYTHIA.Comment: Submitted to the Journal of High Energy Physic
Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study
Background Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours.Methods In this retrospective, international, cross-sectional study, centres were invited to participate in June 22, 2022; each centre joining the study was asked to provide data from medical records on all surgical thyroidectomies consecutively performed from Jan 1, 2019, to Dec 31, 2021. Patients with indeterminate thyroid nodules were divided into three groups according to when they underwent surgery: from Jan 1, 2019, to Feb 29, 2020 (global prepandemic phase), from March 1, 2020, to May 31, 2021 (pandemic escalation phase), and from June 1 to Dec 31, 2021 (pandemic decrease phase). The main outcomes were, for each phase, the number of surgeries for indeterminate thyroid nodules, and in patients with a postoperative diagnosis of thyroid cancers, the occurrence of tumours larger than 10 mm, extrathyroidal extension, lymph node metastases, vascular invasion, distant metastases, and tumours at high risk of structural disease recurrence. Univariate analysis was used to compare the probability of aggressive thyroid features between the first and third study phases. The study was registered on ClinicalTrials.gov, NCT05178186.Findings Data from 157 centres (n=49 countries) on 87 467 patients who underwent surgery for benign and malignant thyroid disease were collected, of whom 22 974 patients (18 052 [78 center dot 6%] female patients and 4922 [21 center dot 4%] male patients) received surgery for indeterminate thyroid nodules. We observed a significant reduction in surgery for indeterminate thyroid nodules during the pandemic escalation phase (median monthly surgeries per centre, 1 center dot 4 [IQR 0 center dot 6-3 center dot 4]) compared with the prepandemic phase (2 center dot 0 [0 center dot 9-3 center dot 7]; p<0 center dot 0001) and pandemic decrease phase (2 center dot 3 [1 center dot 0-5 center dot 0]; p<0 center dot 0001). Compared with the prepandemic phase, in the pandemic decrease phase we observed an increased occurrence of thyroid tumours larger than 10 mm (2554 [69 center dot 0%] of 3704 vs 1515 [71 center dot 5%] of 2119; OR 1 center dot 1 [95% CI 1 center dot 0-1 center dot 3]; p=0 center dot 042), lymph node metastases (343 [9 center dot 3%] vs 264 [12 center dot 5%]; OR 1 center dot 4 [1 center dot 2-1 center dot 7]; p=0 center dot 0001), and tumours at high risk of structural disease recurrence (203 [5 center dot 7%] of 3584 vs 155 [7 center dot 7%] of 2006; OR 1 center dot 4 [1 center dot 1-1 center dot 7]; p=0 center dot 0039).Interpretation Our study suggests that the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic period could have led to an increased occurrence of aggressive thyroid tumours. However, other compelling hypotheses, including increased selection of patients with aggressive malignancies during this period, should be considered. We suggest that surgery for indeterminate thyroid nodules should no longer be postponed even in future instances of pandemic escalation.Funding None.Copyright (c) 2023 Published by Elsevier Ltd. All rights reserved
COVID-19: Is There Evidence for the Use of Herbal Medicines as Adjuvant Symptomatic Therapy?
Background: Current recommendations for the self-management of SARS-Cov-2 disease (COVID-19) include self-isolation, rest, hydration, and the use of NSAID in case of high fever only. It is expected that many patients will add other symptomatic/adjuvant treatments, such as herbal medicines.
Aims: To provide a benefits/risks assessment of selected herbal medicines traditionally indicated for “respiratory diseases” within the current frame of the COVID-19 pandemic as an adjuvant treatment.
Method: The plant selection was primarily based on species listed by the WHO and EMA, but some other herbal remedies were considered due to their widespread use in respiratory conditions. Preclinical and clinical data on their efficacy and safety were collected from authoritative sources. The target population were adults with early and mild flu symptoms without underlying conditions. These were evaluated according to a modified PrOACT-URL method with paracetamol, ibuprofen, and codeine as reference drugs. The benefits/risks balance of the treatments was classified as positive, promising, negative, and unknown.
Results: A total of 39 herbal medicines were identified as very likely to appeal to the COVID-19 patient. According to our method, the benefits/risks assessment of the herbal medicines was found to be positive in 5 cases (Althaea officinalis, Commiphora molmol, Glycyrrhiza glabra, Hedera helix, and Sambucus nigra), promising in 12 cases (Allium sativum, Andrographis paniculata, Echinacea angustifolia, Echinacea purpurea, Eucalyptus globulus essential oil, Justicia pectoralis, Magnolia officinalis, Mikania glomerata, Pelargonium sidoides, Pimpinella anisum, Salix sp, Zingiber officinale), and unknown for the rest. On the same grounds, only ibuprofen resulted promising, but we could not find compelling evidence to endorse the use of paracetamol and/or codeine.
Conclusions: Our work suggests that several herbal medicines have safety margins superior to those of reference drugs and enough levels of evidence to start a clinical discussion about their potential use as adjuvants in the treatment of early/mild common flu in otherwise healthy adults within the context of COVID-19. While these herbal medicines will not cure or prevent the flu, they may both improve general patient well-being and offer them an opportunity to personalize the therapeutic approaches
Strengthening Teaching Digital Competencies: An Imperative in the Face of the Integration of Artificial Intelligence in Higher Education
La rápida evolución de la Inteligencia Artificial (IA) está transformando diversos sectores, incluida la educación superior. La integración efectiva de la IA en los procesos de enseñanza-aprendizaje ofrece oportunidades sin precedentes, como la personalización del aprendizaje, la generación de recursos multimedia enriquecidos y la automatización de tareas administrativas. Sin embargo, a pesar de su potencial, la adopción de estas tecnologías emergentes se ve obstaculizada por la falta de competencias digitales en el cuerpo docente. Este artículo explora el diagnóstico del nivel actual de habilidades tecnológicas de los profesores universitarios, analiza los desafíos y el contexto que enmarcan esta problemática, y presenta una propuesta metodológica para evaluar y fortalecer las competencias digitales necesarias para una integración exitosa de la IA en la enseñanza superior.The rapid evolution of Artificial Intelligence (AI) is transforming various sectors, including higher education. The effective integration of AI into teaching-learning processes offers unprecedented opportunities, such as the personalization of learning, the generation of rich multimedia resources and the automation of administrative tasks. However, despite their potential, the adoption of these emerging technologies is hampered by a lack of digital skills among faculty. This article explores the diagnosis of the current level of technological skills of university professors, analyzes the challenges and context that frame this problem, and presents a methodological proposal to evaluate and strengthen the digital competencies necessary for a successful integration of AI in teaching superior grades