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THE UNAM-KIAS CATALOG OF ISOLATED GALAXIES
Herná,ndez-Toledo, H. M.,Vá,zquez-Mata, J. A.,Martí,nez-Vá,zquez, L. A.,Choi, Yun-Young,Park, Changbom American Institute of Physics 2010 The Astronomical journal Vol.139 No.6
<P>A new catalog of isolated galaxies from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) is presented. A total of 1520 isolated galaxies were found in 1.4 sr of sky. The selection criteria in this UNAM-KIAS catalog are a variation on the criteria developed by Karachentseva, including full redshift information. Through an image processing pipeline that takes advantage of the high-resolution (~0<img entity='farcs' SRC='http://ej.iop.org/icons/Entities/farcs.gif' ALT='farcs' ALIGN='BOTTOM' />4 pixel<SUP>–1</SUP>) and high dynamic range of the SDSS images, a uniform g-band morphological classification for all these galaxies is presented. We identify 80% (Sa-Sm) spirals (50% later than Sbc types) on one hand, and a scarce population of early-type E (6.5%) and S0 (8%) galaxies amounting to 14.5% on the other hand. This magnitude-limited catalog is ~80% complete at 16.5, 15.6, 15.2, 14.6, and 14.4 mag in the ugriz bands, respectively. Some representative physical properties including SDSS magnitudes and color distributions, color-color diagrams, absolute magnitude-color, and concentration-color diagrams as a function of morphological type are presented. The UNAM-KIAS Morphological Atlas is also released along with this paper. For each galaxy of a type later than Sa, a mosaic is presented that includes (1) a g-band logarithmic image, (2) a g-band filtered-enhanced image where a Gaussian kernel of various sizes was applied, and (3) a red giant branch color image from the SDSS database. For E/S0/Sa galaxies, in addition to the images in (1), (2), and (3), plots of r-band surface brightness and geometric profiles (ellipticity ε, position angle PA, and A<SUB>4</SUB>/B<SUB>4</SUB> coefficients of the Fourier series expansions of deviations of a pure ellipse) are provided. The size of the sample, the redshift completeness, the availability of high-quality multicolor photometric data and detailed morphological and spectroscopic information make the UNAM-KIAS catalog of isolated galaxies a suitable sample to address important issues such as (1) comparative studies of environmental effects, (2) constraining the currently competing scenarios of galaxy formation and evolution, (3) the nature and evolution of elliptical and spiral galaxies in the field, (4) the spectral properties of a statistically significant number of isolated galaxies and their evolution as a function of redshift, and (5) the fraction of active galactic nuclei in isolated environments, among other important topics. The optimization and estimation of new structural parameters as well as important information to complement existing ones in other wavelengths is being carried out.</P>
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Akram Herná,ndez-Vá,squez,Horacio Chacó,n-Torrico 한국역학회 2019 Epidemiology and Health Vol.41 No.-
OBJECTIVES: Early initiation of breastfeeding (EIBF) is one of the most cost-effective strategies to reduce neonatal mortality. We sought to determine the prevalence and determinants of EIBF in Peru. METHODS: We performed a cross-sectional analytical study of the 2018 Peruvian Demographic and Family Health Survey as a secondary data source. In total, 19,595 children born during the 5 years prior to the survey were included in the study. The dependent variable (EIBF status), socio-demographic variables, and pregnancy-related variables were analyzed using a multivariate logistic regression model to identify the determinants of EIBF. RESULTS: The prevalence of EIBF in the study population was 49.7%. Cesarean deliveries were associated with a lower likelihood of EIBF (adjusted odds ratio [aOR], 0.06; 95% confidence interval [CI], 0.05 to 0.07) than were vaginal deliveries. Newborns born at public health centers (aOR, 1.37; 95% CI, 1.15 to 1.65) had a higher rate of EIBF than those not born at public or private health centers. Women from the jungle region (aOR, 2.51; 95% CI, 2.17 to 2.89) had higher odds of providing EIBF than those from the coast. Mothers with more than a secondary education (aOR, 0.65; 95% CI, 0.55 to 0.76) were less likely to breastfeed during the first hour of the newborn’s life than women with primary or no education. CONCLUSIONS: More than half of Peruvian children do not breastfeed during the first hour after birth. The major determinants of EIBF status were the delivery mode and the region of maternal residence. Strategies are needed to promote early breastfeeding practices.
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Yaw motion analysis of a FPSO turret mooring system under wave drift forces
Sanchez-Mondragon, J.,Vá,zquez-Herná,ndez, A.O.,Cho, S.K.,Sung, H.G. Elsevier 2018 Applied ocean research Vol.74 No.-
<P><B>Abstract</B></P> <P>In order to evaluate the dynamic behavior of a FPSO-turret system, experimental tests in engineering wave basin have been performed. During the realization of experimental test large slow yaw rotations were detected in the dynamic behavior of the vessel during regular and irregular wave conditions tests. In order to study this phenomenon, an analytical method was developed in order to predict the maximum yaw angle reached under the slow yaw varying oscillations of a single point moored FPSO-turret system dependent of the regular mean wave drift forces and the turret position. The results for the proposed analytical method were verified by comparing it with experimental and simulated results. Then, the proposed method allows to identify the critical regular wave periods than can provoke large yaw rotations as an alternative for the stability tests by bifurcation analysis. On the other hand, the performed yaw motion simulations take into account the following aspects: the turret position, and the force and momentum associated with the mooring system variations (in function of the FPSO center of gravity positions and regular mean wave drift forces). Analyzing the time domain simulations it is possible to identify that large yaw motion is reached faster when the turret is near the CG and so, as the turret moves away, the yaw motions become slower.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Analytical yaw stability condition is developed. </LI> <LI> FPSO-turret dynamic study under wave drift forces on regular wave conditions. </LI> <LI> Numerical simulations and experimental results compared the yaw stability condition. </LI> <LI> Turret position configuration variations associated with yaw instabilities. </LI> </UL> </P>
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The Delta Scuti star 38 Eri from the ground and from space
Paparó,, M,Kollá,th, Z,Shobbrook, R R,Matthews, J M,Antoci, V,Benkő,, J M,Park, N-K,Mirtorabi, M T,Luedeke, K,Kusakin, A,Bogná,r, Zs,Só,dor, Á,Garcí,a-Hern&aac Oxford University Press 2018 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.477 No.4
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Valdé,s Herná,ndez, Maria del Carmen,Cox, Simon R.,Kim, Jaeil,Royle, Natalie A.,Muñ,oz Maniega, Susana,Gow, Alan J.,Anblagan, Devasuda,Bastin, Mark E.,Park, Jinah,Starr, John M.,Ward Elsevier 2017 NEUROBIOLOGY OF AGING Vol.52 No.-
<P>Structural measures of the hippocampus have been linked to a variety of memory processes and also to broader cognitive abilities. Gross volumetry has been widely used, yet the hippocampus has a complex formation, comprising distinct subfields which may be differentially sensitive to the deleterious effects of age, and to different aspects of cognitive performance. However, a comprehensive analysis of multidomain cognitive associations with hippocampal deformations among a large group of cognitively normal older adults is currently lacking. In 654 participants of the Lothian Birth Cohort 1936 (mean age = 72.5, SD = 0.71 years), we examined associations between the morphology of the hippocampus and a variety of memory tests (spatial span, letter-number sequencing, verbal recall, and digit backwards), as well as broader cognitive domains (latent measures of speed, fluid intelligence, and memory). Following correction for age, sex, and vascular risk factors, analysis of memory subtests revealed that only right hippocampal associations in relation to spatial memory survived type 1 error correction in subiculum and in CA1 at the head (<I>β</I> = 0.201, <I>p</I> = 5.843 × 10<SUP>−4</SUP>, outward), and in the ventral tail section of CA1 (<I>β</I> = −0.272, <I>p</I> = 1.347 × 10<SUP>−5</SUP>, inward). With respect to latent measures of cognitive domains, only deformations associated with processing speed survived type 1 error correction in bilateral subiculum (<I>β</I><SUB><I>absolute</I></SUB> ≤ 0.247, <I>p</I> < 1.369 × 10<SUP>−4</SUP>, outward), bilaterally in the ventral tail section of CA1 (<I>β</I><SUB><I>absolute</I></SUB> ≤ 0.242, <I>p</I> < 3.451 × 10<SUP>−6</SUP>, inward), and a cluster at the left anterior-to-dorsal region of the head (<I>β</I> = 0.199, <I>p</I> = 5.220 × 10<SUP>−6</SUP>, outward). Overall, our results indicate that a complex pattern of both inward and outward hippocampal deformations are associated with better processing speed and spatial memory in older age, suggesting that complex shape-based hippocampal analyses may provide valuable information beyond gross volumetry.</P>
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Detonation onset in a thermally stratified constant volume reactor
Sow, Aliou,Lee, Bok Jik,Herná,ndez Pé,rez, Francisco E.,Im, Hong G. Elsevier 2019 Proceedings of the Combustion Institute Vol.37 No.3
<P><B>Abstract</B></P> <P>Understanding detonation development from a flame kernel initiated by a pre-ignition event is important for modern internal combustion (IC) engines operating at boosted conditions. To provide fundamental insights into the effects of bulk gas temperature stratification on the characteristics of detonation development, one-dimensional high fidelity simulations were conducted for a constant volume reactor filled with a thermally stratified reactive stoichiometric hydrogen/air mixture. A linear temperature variation in the upstream end-gas was introduced to represent the thermal stratification of the bulk mixture, and the evolution from the initial deflagration flame front to detonation development was examined. The results showed that the bulk-gas temperature gradient has a significant effect on the run-up time and intensity of the developing detonation. Detailed analyses further revealed that the mechanism of detonation development is qualitatively different for the positive and negative temperature gradient cases. In the former, the detonation development is initiated by the end-gas autoignition at the wall, while the latter exhibits detonation development following the process of the self-acceleration of the flame similar to the deflagration-to-detonation transition. This behavior is attributed to the longer residence time in the end-gas allowing the reinforcement by the interaction of incident and reflected pressure waves during the flame propagation, and results in the peak pressure even higher than the case with the same level of positive temperature gradient. Furthermore, yet another detonation development pattern was observed for the negative temperature gradient condition in the presence of a uniform temperature region just ahead of the flame. In this case, autoignition was found to start in the middle of the bulk end-gas, and subsequently leads to the transition to detonation. The results demonstrate the importance of the bulk gas conditions in predicting the detonation development, which corroborate the existing theoretical framework.</P>
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