150 research outputs found
Determination of pulsation periods and other parameters of 2875 stars classified as MIRA in the All Sky Automated Survey (ASAS)
We have developed an interactive PYTHON code and derived crucial ephemeris
data of 99.4% of all stars classified as 'Mira' in the ASAS data base,
referring to pulsation periods, mean maximum magnitudes and, whenever possible,
the amplitudes among others. We present a statistical comparison between our
results and those given by the AAVSO International Variable Star Index (VSX),
as well as those determined with the machine learning automatic procedure of
Richards et al. 2012. Our periods are in good agreement with those of the VSX
in more than 95% of the stars. However, when comparing our periods with those
of Richards et al, the coincidence rate is only 76% and most of the remaining
cases refer to aliases. We conclude that automatic codes require still more
refinements in order to provide reliable period values. Period distributions of
the target stars show three local maxima around 215, 275 and 330 d, apparently
of universal validity, their relative strength seems to depend on galactic
longitude. Our visual amplitude distribution turns out to be bimodal, however
1/3 of the targets have rather small amplitudes (A 2.5) and could
refer to semi-regular variables (SR). We estimate that about 20% of our targets
belong to the SR class. We also provide a list of 63 candidates for period
variations and a sample of 35 multiperiodic stars which seem to confirm the
universal validity of typical sequences in the double period and in the
Petersen diagramsComment: 14 pages, 14 figures, and 8 tables. Accepted to The Astrophysical
Journal Supplement Series, September 201
"Justificaciones discursivas para el consumo de marihuana y cocaína en jóvenes de estratos medios altos en la ciudad de Temuco". CORECE IX región-Universidad Católica de Temuco-Harmos Ltda.
Estudio que tiene por objetivo comprender las elaboraciones discursivas de jóvenes de enseñanza media, universitaria y del
mundo laboral respecto del consumo de marihuana y cocaína y elaborar propuestas comunicacionales apropiadas al discurso de los jóvenes para la prevención del consumo de marihuana y cocaína
Seismic imaging of the Northern Andean subduction zone from teleseismic tomography: a torn and fragmented Nazca slab
The Nazca-South America subduction zone in Ecuador is characterized by a complicated along-strike geometry as the slab transitions from flat slab subduction in the south, with the Peruvian flat slab, to what has been characterized as ‘normal’ dipping subduction beneath central Ecuador. Plate convergence additionally changes south to north as the trench takes on a convex shape. Highly heterogeneous bathymetry at the trench, including the aseismic oceanic
Carnegie Ridge (CR), and sparse intermediate-depth seismicity has led many to speculate about the behaviour of the downgoing plate at depth. In this study, we present a finite-frequency teleseismic P-wave tomography model of the northern Andes beneath Ecuador and Colombia from 90 to 1200 km depth. Our model builds on prior tomography models in South America by adding relative traveltime residuals recorded at stations in Ecuador. The complete
data set is comprised of 114 096 relative traveltime residuals from 1133 stations across South America, with the added data serving to refine the morphology of the Nazca slab in the mantle beneath the northern Andes. Our tomography model shows a Nazca slab with a fragmented along-strike geometry and the first teleseismic images of several proposed slab tears in this region. At the northern edge of the Peruvian flat slab in southern Ecuador, we image a shallow
tear at 95–200 km depth that appears to connect mantle flow from beneath the flat slab to the Ecuadorian Arc. Beneath central Ecuador at the latitudes of the CR, the Nazca slab is continuous into the lower mantle. Beneath southern Colombia, the Malpelo Tear breaks the Nazca slab below ∼200 km depth
PainPoints: A Framework for Language-based Detection of Chronic Pain and Expert-Collaborative Text-Summarization
Chronic pain is a pervasive disorder which is often very disabling and is
associated with comorbidities such as depression and anxiety. Neuropathic Pain
(NP) is a common sub-type which is often caused due to nerve damage and has a
known pathophysiology. Another common sub-type is Fibromyalgia (FM) which is
described as musculoskeletal, diffuse pain that is widespread through the body.
The pathophysiology of FM is poorly understood, making it very hard to
diagnose. Standard medications and treatments for FM and NP differ from one
another and if misdiagnosed it can cause an increase in symptom severity. To
overcome this difficulty, we propose a novel framework, PainPoints, which
accurately detects the sub-type of pain and generates clinical notes via
summarizing the patient interviews. Specifically, PainPoints makes use of large
language models to perform sentence-level classification of the text obtained
from interviews of FM and NP patients with a reliable AUC of 0.83. Using a
sufficiency-based interpretability approach, we explain how the fine-tuned
model accurately picks up on the nuances that patients use to describe their
pain. Finally, we generate summaries of these interviews via expert
interventions by introducing a novel facet-based approach. PainPoints thus
enables practitioners to add/drop facets and generate a custom summary based on
the notion of "facet-coverage" which is also introduced in this work
The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence
The collapse of a mine tailings dam and subsequent flood in SE Brazil on 5 November 2015 was preceded by a small-magnitude seismic sequence. In this report, we explore the spatiotemporal associations between the seismic events and the accident and discuss their possible connection. We also analyze the signals generated by the turbulent mudflow, as recorded by the Brazilian Seismographic Network (RSBR). In light of our observations, we propose as possible contributing factor for the dam collapse either ground shaking and/or soil liquefaction triggered by the earthquakes. The possibility of such a small-magnitude earthquake contributing to the collapse of a tailings dam raises important concerns regarding safety and related legislation of dams in Brazil and the world. ©2016. American Geophysical Union.H.A.D. and M.A. acknowledge support from Sao Paulo Research Foundation FAPESP grant 2014/09455-3 and CNPq grant 30.6547/2013-9.Peer reviewe
Factors associated with producing a scientific publication during medical training: evidence from a cross-sectional study of 40 medical schools in Latin America [version 2; peer review: 2 approved]
"Background: Scientific publication during medical training is key to
promoting enduring cutting-edge knowledge. The promotion of
science among medical students in Latin America is a multisectoral
issue that is hampered by the lack of governmental knowledge to
invest in national research, as well as by the lack of support from local
universities. This study aims to determine the factors associated with
the production of a scientific publication during medical training
among Latin American medical students of local scientific societies.
Methods: This is a secondary data analysis of a cross-sectional study
conducted in 2016 that assessed the use of information and
communication technologies (ICTs) among medical students from 40
local scientific societies of medical students affiliated with FELSOCEM.
Teams from each local scientific society surveyed self-reported
scientific publications and explored their association with
socioeconomic, academic, and research training conditions. We applied nested models to identify the covariates associated with selfreported scientific publication, obtaining a parsimonious mixedeffects multilevel model grouped by medical scientific society.
Results: Of 11,587 participants, the prevalence of scientific
publications increased in 36% among medical students affiliated to a
Scientific Society of Medical Students [parsimonious prevalence ratio
(pPR)=1.36, 95%CI=1.16–1.59], 51% among medical students with
advanced English proficiency [pPR=1.51, 95%CI=1.21 – 1.87], 85%
among medical students who attended a scientific writing skills course
[pPR=1.85, 95%CI=1.59–2.15], 81% among medical students who use
Sci-Hub [pPR=1.81, 95%CI=1.50–2.20], and 108% among medical
students who have access to a pirated academic account [pPR=2.08,
95%CI=1.83–2.36].
Conclusions: Producing a scientific publication among medical
students is associated with being affiliated to a scientific society of
medical students, English proficiency, training in scientific writing, use
of Sci-Hub, and pirated academic accounts. The results will help
clinical educators and medical programs improve resources for
training students in high-quality research
Triggered crustal earthquake swarm across subduction segment boundary after the 2016 Pedernales, Ecuador megathrust earthquake
Megathrust ruptures and the ensuing postseismic deformation cause stress changes that may induce seismicity on upper plate crustal faults far from the coseismic rupture area. In this study, we analyze seismic swarms that occurred in the north Ecuador area of Esmeraldas, beginning two months after the 2016 M 7.8 Pedernales, Ecuador megathrust earthquake. The Esmeraldas region is 70 km from the Pedernales rupture area in a separate segment of the subduction zone. We characterize the Esmeraldas sequence, relocating the events using manual arrival time picks and a local a-priori 3D velocity model. The earthquake locations from the Esmeraldas sequence outline an upper plate fault or shear zone. The sequence contains one major swarm and several smaller swarms. Moment tensor solutions of several events include normal and strike-slip motion and non-double-couple components. During the main swarm, earthquake hypocenters increase in distance from the first event over time, at a rate of a few hundred meters per day, consistent with fluid diffusion. Events with similar waveforms occur within the sequence, and a transient is seen in time series of nearby GPS stations concurrent with the seismicity. The events with similar waveforms and the transient in GPS time series suggest that slow aseismic slip took place along a crustal normal fault during the sequence. Coulomb stress calculations show a positive Coulomb stress change in the Esmeraldas region, consistent with seismicity being triggered by the Pedernales mainshock and large aftershocks. The characteristics of the seismicity indicate that postseismic deformation involving fluid flow and slow slip activated upper plate faults in the Esmeraldas area. These findings suggest the need for further investigation into the seismic hazard potential of shallow upper plate faults and the potential for megathrust earthquakes to trigger slow-slip and shallow seismicity across separate segments of subduction zones
Women's knowledge about cervical cancer risk factors, screening, and reasons for non-participation in cervical cancer screening programme in Estonia
<p>Abstract</p> <p>Background</p> <p>The attendance rate in Estonian cervical cancer screening programme is too low therefore the programme is hardly effective. A cross-sectional population based survey was performed to identify awareness of cervical cancer risk factors, reasons why women do not want to participate in cervical screening programme and wishes for better organisation of the programme.</p> <p>Method</p> <p>An anonymous questionnaire with a covering letter and a prepaid envelope was sent together with the screening invitation to 2942 randomly selected women. Results are based on the analysis of 1054 (36%) returned questionnaires.</p> <p>Results</p> <p>Main reasons for non-participation in the national screening programme were a recent visit to a gynaecologist (42.3%), fear to give a Pap-smear (14.3%), long appointment queues (12.9%) and unsuitable reception hours (11.8%). Fear to give a Pap-smear was higher among women aged 30 and 35 than 50 and 55 (RR 1.46; 95% CI: 0.82-2.59) and women with one or no deliveries (RR 1.56, 95% CI: 0.94-2.58). In general, awareness of cervical cancer risk factors is poor and it does not depend on socio-demographic factors. Awareness of screening was higher among Estonians than Russians (RR 1.64, 95% CI: 1.46-1.86). Most women prefer to receive information about screening from personally mailed invitation letters (74.8%).</p> <p>Conclusions</p> <p>Women need more information about cervical cancer risk factors and the screening programme. They prefer personally addressed information sharing. Minority groups should be addressed in their own language. A better collaboration with service providers and discouraging smears outside the programme are also required.</p
Fast Localization of Optic Disc and Fovea in Retinal Images for Eye Disease Screening
ABSTRACT Optic disc (OD) and fovea locations are two important anatomical landmarks in automated analysis of retinal disease in color fundus photographs. This paper presents a new, fast, fully automatic optic disc and fovea localization algorithm developed for diabetic retinopathy (DR) screening. The optic disc localization methodology comprises of two steps. First, the OD location is identified using template matching and directional matched filter. To reduce false positives due to bright areas of pathology, we exploit vessel characteristics inside the optic disc. The location of the fovea is estimated as the point of lowest matched filter response within a search area determined by the optic disc location. Second, optic disc segmentation is performed. Based on the detected optic disc location, a fast hybrid level-set algorithm which combines the region information and edge gradient to drive the curve evolution is used to segment the optic disc boundary. Extensive evaluation was performed on 1200 images (Messidor) composed of 540 images of healthy retinas, 431 images with DR but no risk of macular edema (ME), and 229 images with DR and risk of ME. The OD location methodology obtained 98.3% success rate, while fovea location achieved 95% success rate. The average mean absolute distance (MAD) between the OD segmentation algorithm and "gold standard" is 10.5% of estimated OD radius. Qualitatively, 97% of the images achieved Excellent to Fair performance for OD segmentation. The segmentation algorithm performs well even on blurred images
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