3,575 research outputs found
Worst-case evaluation complexity of non-monotone gradient-related algorithms for unconstrained optimization
Evaluation of neck circumference as a predictor of elevated cardiometabolic risk outcomes in 5–8-year-old Brazilian children
Background: Childhood overweight and obesity is a global health problem that continues to worsen in many low- and middle-income countries. Low-cost measurements for monitoring overweight and relative metabolic risk, such as neck circumference (NC), should be evaluated in different populations and age groups. /
Aim: To test associations of NC and BMI with cardiometabolic parameters in 5-8-year-old Brazilian children. /
Methods: This cross-sectional study carried out from 2004–2006 measured height, weight and NC by anthropometry, and estimated fat and fat-free mass by bioelectrical impedance. Cardiometabolic risk factors assessed were systolic and diastolic blood pressure, high- and low-density lipoprotein cholesterol, triglycerides, and homeostatic model assessment of insulin resistance (HOMA). Associations of NC and BMI with cardiometabolic risk factors were tested using multiple regression and precision-recall plot analysis. /
Results: Analyses included 371 children (52% female). NC associated positively with BMI, fat mass, and fat-free mass, and with systolic blood pressure and HOMA following adjustment for age in sex-stratified multiple regression models. However, the latter relationships largely disappeared following adjustment for BMI. Area under the curve for NC or BMI in association with systolic blood pressure or HOMA >90th percentile was low in the pooled sample, indicating poor classifier performance. /
Conclusions: NC and BMI demonstrated similar associations with cardiometabolic risk factors, although NC mostly did not correlate with risk factors independently of BMI. In contrast to previous studies, NC was a poor classifier of cardiometabolic risk factors in children. The association of NC with both fat and fat-free mass may aid in explaining its poor performance
GYES, a multifibre spectrograph for the CFHT
We have chosen the name of GYES, one of the mythological giants with one
hundred arms, offspring of Gaia and Uranus, for our instrument study of a
multifibre spectrograph for the prime focus of the Canada-France-Hawaii
Telescope. Such an instrument could provide an excellent ground-based
complement for the Gaia mission and a northern complement to the HERMES project
on the AAT. The CFHT is well known for providing a stable prime focus
environment, with a large field of view, which has hosted several imaging
instruments, but has never hosted a multifibre spectrograph. Building upon the
experience gained at GEPI with FLAMES-Giraffe and X-Shooter, we are
investigating the feasibility of a high multiplex spectrograph (about 500
fibres) over a field of view 1 degree in diameter. We are investigating an
instrument with resolution in the range 15000 to 30000, which should provide
accurate chemical abundances for stars down to 16th magnitude and radial
velocities, accurate to 1 km/s for fainter stars. The study is led by
GEPI-Observatoire de Paris with a contribution from Oxford for the study of the
positioner. The financing for the study comes from INSU CSAA and Observatoire
de Paris. The conceptual study will be delivered to CFHT for review by October
1st 2010.Comment: Contributed talk at the Gaia ELSA conference 2010, S\`evres 7-11 June
2010, to be published on the EAS Series, Editors: C. Turon, F. Arenou & F.
Meynadie
Looking backward: From Euler to Riemann
We survey the main ideas in the early history of the subjects on which
Riemann worked and that led to some of his most important discoveries. The
subjects discussed include the theory of functions of a complex variable,
elliptic and Abelian integrals, the hypergeometric series, the zeta function,
topology, differential geometry, integration, and the notion of space. We shall
see that among Riemann's predecessors in all these fields, one name occupies a
prominent place, this is Leonhard Euler. The final version of this paper will
appear in the book \emph{From Riemann to differential geometry and relativity}
(L. Ji, A. Papadopoulos and S. Yamada, ed.) Berlin: Springer, 2017
Comparing six evolutionary population synthesis models through spectral synthesis on galaxies
We compare six popularly used evolutionary population synthesis (EPS) models
(BC03, CB07, Ma05, GALEV, GRASIL, Vazdekis/Miles) through fitting the full
optical spectra of six representative types of galaxies (star-forming and
composite galaxies, Seyfert 2s, LINERs, E+A and early-type galaxies), which are
taken from the Sloan Digital Sky Survey (SDSS). Throughout our paper, we use
the simple stellar populations (SSPs) from each EPS model and the software
STARLIGHT to do our fits. Our main results are: Using different EPS models the
resulted numerical values of contributed light fractions change obviously, even
though the dominant populations are consistent. The stellar population
synthesis does depend on the selection of age and metallicity, while it does
not depend on the stellar evolution track much. The importance of young
populations decreases from star-forming, composite, Seyfert 2, LINER to
early-type galaxies, and E+A galaxies lie between composite galaxies and
Seyfert 2s in most cases. We conclude that different EPS models do derive
different stellar populations, so that it is not reasonable to directly compare
stellar populations estimated from different EPS models. To get reliable
results, we should use the same EPS model for the compared samples.Comment: 13 pages, 4 figures, accepted for publication in A&
On the Existence of Undistorted Progressive Waves (UPWs) of Arbitrary Speeds in Nature
We present the theory, the experimental evidence, and fundamental physical
consequences concerning the existence of families of undistorted progressive
waves (UPWs) of arbitrary speeds , which are solutions of the
homogeneous wave equation, Maxwell equations, and Dirac and Weyl equations.Comment: 77 pages, Latex article, with figures. Includes corrections to the
published versio
Incidence of rotavirus infection in children with gastroenteritis attending Jos university teaching hospital, Nigeria
This study was conducted to determine the incidence of rotavirus infection in children with gastroenteritis attending Jos university teaching hospital, Plateau State. A total of 160 children with acute diarrhea were selected by random sampling. Stool samples were obtained and assayed for rotavirus antigens by enzyme linked immunosorbent assay technique using standard diagnostic BIOLINE Rotavirus kit. Demographic data of parents were also recorded. Rotavirus were detected in faeces of 22(13.8%) children with acute diarrhea, 90.9% of positive cases of rotavirus gastroenteritis were under 2 years of age with highest prevalence in children 7-12 months of age. Males excreted rotavirus at a significant higher rate than females (P < 0.05). Rotavirus excretion was highest when all three symptoms (diarrhea, fever and vomiting) occurred in the same child (7.5%) and lower when 2 symptoms occurred together (diarrhea and vomiting) with 3.8%, diarrhea and fever with 1.3% and lowest when diarrhea occurred alone with 1.3%. Playing with toys, attending day care, distance of source of water from toilet, eating of food not requiring cooking and playing with other children may serve as predisposing factors of rotavirus disease in these children
Polimiosite : investigação clínica em duas irmãs
We present an investigation of a case of polymyositis affecting two sisters of one same parenthood. Their cases have been documented for almost two decades, being investigated by means of a diagnostic protocol which combined clinical findings as well as laboratorial, histopathological and image tests. In both cases, clinical manifestations started in childhood, without signs of involvement of the central and peripheral nervous system. Both patients proved to respond to a therapeutics based on corticosteroids. The degree of relatedness between their parents corroborate the notion that genetic factors may contribute to the development of the disease. ___________________________________________________________________________________________________ RESUMOApresentamos a investigação de dois casos de polimiosite, ocorridos entre irmãs de uma mesma
filiação. Seus casos foram documentados ao longo de quase duas décadas, tendo sido diagnosticados utilizando-
se de protocolo diagnóstico que combinou achados clínicos, exames laboratoriais, histopatológicos e por
imagem. Em ambos os casos, as manifestações clínicas se iniciaram ainda na infância, sendo constatada
ausência de acometimento do sistema nervoso central ou periférico. Ambas as pacientes responderam
satisfatoriamente a terapia baseada em corticosteróide. O grau de parentesco entre os genitores das pacientes
sugere que fatores genéticos podem predispor ao desenvolvimento da doença
Applied immuno-epidemiological research: an approach for integrating existing knowledge into the statistical analysis of multiple immune markers.
BACKGROUND: Immunologists often measure several correlated immunological markers, such as concentrations of different cytokines produced by different immune cells and/or measured under different conditions, to draw insights from complex immunological mechanisms. Although there have been recent methodological efforts to improve the statistical analysis of immunological data, a framework is still needed for the simultaneous analysis of multiple, often correlated, immune markers. This framework would allow the immunologists' hypotheses about the underlying biological mechanisms to be integrated. RESULTS: We present an analytical approach for statistical analysis of correlated immune markers, such as those commonly collected in modern immuno-epidemiological studies. We demonstrate i) how to deal with interdependencies among multiple measurements of the same immune marker, ii) how to analyse association patterns among different markers, iii) how to aggregate different measures and/or markers to immunological summary scores, iv) how to model the inter-relationships among these scores, and v) how to use these scores in epidemiological association analyses. We illustrate the application of our approach to multiple cytokine measurements from 818 children enrolled in a large immuno-epidemiological study (SCAALA Salvador), which aimed to quantify the major immunological mechanisms underlying atopic diseases or asthma. We demonstrate how to aggregate systematically the information captured in multiple cytokine measurements to immunological summary scores aimed at reflecting the presumed underlying immunological mechanisms (Th1/Th2 balance and immune regulatory network). We show how these aggregated immune scores can be used as predictors in regression models with outcomes of immunological studies (e.g. specific IgE) and compare the results to those obtained by a traditional multivariate regression approach. CONCLUSION: The proposed analytical approach may be especially useful to quantify complex immune responses in immuno-epidemiological studies, where investigators examine the relationship among epidemiological patterns, immune response, and disease outcomes
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