bluuebunny/crossref_metadata_2025_split huggingface dataset:
Associations between bottle-feeding intensity and maternal encouragement of bottle-emptying
Authors: Ventura Alison K , Garcia Patsy , Schaffner Andrew A 
Published: September 2017

AbstractObjectiveTo explore longitudinal associations between bottle-feeding and maternal encouragement of infant bottle-emptying during the first 6 months of infancy.DesignMothers completed questionnaires during the third trimester of pregnancy, then monthly during the first 6 months postpartum. Questionnaires assessed family demographics, maternal and infant weight status, infant feeding patterns and maternal encouragement of infant bottle-emptying.SettingThe Infant Feeding Practices Study 2, conducted by the US Centers for Disease Control and Prevention and the Food and Drug Administration.SubjectsMothers (n1776).ResultsRepeated-measures regression was used to explore associations between bottle-feeding intensity (BFI; defined as the percentage of daily feedings that were from a bottle) and encouragement of bottle-emptying. Mothers who reported consistently high or consistently low BFI also exhibited consistently higher or lower frequency of encouraging their infants to empty the bottle (respectively) across the first 6 months of infancy, whereas mothers who reported increases in their BFI also exhibited concomitant increases in the frequency to which they encouraged their infants to finish the bottle. More frequent encouragement of bottle-emptying was also associated with feeding expressed breast milk (P<0·001), and lower parity (P=0·01), pre-pregnancy BMI (P=0·002) and infant birth weight (P=0·001).ConclusionsMore frequent use of bottles for infant feeding was significantly associated with more frequent encouragement of bottle-emptying. Further research using causal designs is needed to better understand whether the use of bottles promotes this controlling feeding practice or whether mothers with more controlling feeding practices opt to bottle-feed.
Quantitative Studies of Endothelial Cell Fibronectin and Filamentous Actin (F-Actin) Coalignment in Response to Shear Stress
Authors: Gong Xianghui , Zhao Xixi , Li Bin , Sun Yan , Liu Meili , Huang Yan , Jia Xiaoling , Ji Jing , Fan Yubo 
Published: September 2017

AbstractBoth fibronectin (FN) and filamentous actin (F-actin) fibers play a critical role for endothelial cells (ECs) in responding to shear stress and modulating cell alignment and functions. FN is dynamically coupled to the F-actin cytoskeleton via focal adhesions. However, it is unclear how ECs cooperatively remodel their subcellular FN matrix and intracellular F-actin cytoskeleton in response to shear stress. Current studies are hampered by the lack of a reliable and sensitive quantification method of FN orientation. In this study, we developed a MATLAB-based feature enhancement method to quantify FN and F-actin orientation. The role of F-actin in FN remodeling was also studied by treating ECs with cytochalasin D. We have demonstrated that FN and F-actin codistributed and coaligned parallel to the flow direction, and that F-actin alignment played an essential role in regulating FN alignment in response to shear stress. Our findings offer insight into how ECs cooperatively remodel their subcellular ECM and intracellular F-actin cytoskeleton in response to mechanical stimuli, and are valuable for vascular tissue engineering.
Studies of synoptic solar activity using Kodaikanal Ca K data
Authors: Raju K. P. 
Published: September 2017

AbstractThe chromospheric network, the bright emission network seen in the chromospheric lines such as Ca ii K and Hα, outline the supergranulation cells. The Ca images are dominated by the chromospheric network and plages which are good indicators of solar activity. Further, the Ca line is a good proxy to the UV irradiance which is particularly useful in the pre-satellite era where UV measurements are not available. The Ca spectroheliograms of the Sun from Kodaikanal have a data span of about 100 years and covers over 9 solar cycles. The archival data is now available in the digitized form. Programs have been developed to obtain the activity indices and the length scales of the chromospheric network from the data. The preliminary results from the analysis are reported here. It is shown that the Ca ii K intensity and the network boundary width are dependent on the solar cycle.
The Influences of Stellar Activity on Planetary Atmospheres
Authors: Johnstone Colin P. 
Published: September 2017

AbstractOn evolutionary timescales, the atmospheres of planets evolve due to interactions with the planet's surface and with the planet's host star. Stellar X-ray and EUV (=’XUV’) radiation is absorbed high in the atmosphere, driving photochemistry, heating the gas, and causing atmospheric expansion and mass loss. Atmospheres can interact strongly with the stellar winds, leading to additional mass loss. In this review, I summarise some of the ways in which stellar output can influence the atmospheres of planets. I will discuss the importance of simultaneously understanding the evolution of the star's output and the time dependent properties of the planet's atmosphere.
Modelling coronal electron density and temperature profiles based on solar magnetic field observations
Authors: Gómez J. M. Rodríguez , Vieira L. E. Antunes , Lago A. Dal , Palacios J. , Balmaceda L. A. , Stekel T. 
Published: September 2017

AbstractThe density and temperature profiles in the solar corona are complex to describe, the observational diagnostics is not easy. Here we present a physics-based model to reconstruct the evolution of the electron density and temperature in the solar corona based on the configuration of the magnetic field imprinted on the solar surface. The structure of the coronal magnetic field is estimated from Potential Field Source Surface (PFSS) based on magnetic field from both observational synoptic charts and a magnetic flux transport model. We use an emission model based on the ionization equilibrium and coronal abundances from CHIANTI atomic database 8.0. The preliminary results are discussed in details.
Nickel-Phosphorous Development for Total Solar Irradiance Measurement
Authors: Carlesso F. , Berni L. A. , Vieira L. E. A. , Savonov G. S. , Nishimori M. , Lago A. Dal , Miranda E. 
Published: September 2017

AbstractThe development of an absolute radiometer instrument is currently a effort at INPE for TSI measurements. In this work, we describe the development of black Ni-P coatings for TSI radiometers absorptive cavities. We present a study of the surface blackening process and the relationships between morphological structure, chemical composition and coating absorption. Ni-P deposits with different phosphorous content were obtained by electroless techniques on aluminum substrates with a thin zincate layer. Appropriate phosphorus composition and etching parameters process produce low reflectance black coatings.
Evolution of the Active Region NOAA 12443 based on magnetic field extrapolations: preliminary results
Authors: Chicrala André , Dallaqua Renato Sergio , Vieira Luis Eduardo Antunes , Lago Alisson Dal , Gómez Jenny Marcela Rodríguez , Palacios Judith , Stekel Tardelli Ronan Coelho , Costa Joaquim Eduardo Rezende , da Silva Rockenbach Marlos 
Published: September 2017

AbstractThe behavior of Active Regions (ARs) is directly related to the occurrence of some remarkable phenomena in the Sun such as solar flares or coronal mass ejections (CME). In this sense, changes in the magnetic field of the region can be used to uncover other relevant features like the evolution of the ARs magnetic structure and the plasma flow related to it. In this work we describe the evolution of the magnetic structure of the active region AR NOAA12443 observed from 2015/10/30 to 2015/11/10, which may be associated with several X-ray flares of classes C and M. The analysis is based on observations of the solar surface and atmosphere provided by HMI and AIA instruments on board of the SDO spacecraft. In order to investigate the magnetic energy buildup and release of the ARs, we shall employ potential and linear force free extrapolations based on the solar surface magnetic field distribution and the photospheric velocity fields.
The influence of eclipses in the stellar radio emission
Authors: Selhorst Caius Lucius , Valio Adriana 
Published: September 2017

AbstractHere we simulate the shape of a planetary transit observed at radio wavelengths. The simulations use a light curve of the K4 star HAT-P-11 and its hot Jupiter companion as proxy. From the HAT-P-11 optical light curve, a prominent spot was identified (1.10 RP and 0.6 IC). On the radio regime, the limb brighting of 30% was simulated by a quadratic function, and the active region was assumed to have the same size of the optical spot. Considering that the planet size is 6.35% of the the stellar radius, for the quiet star regions the transit depth is smaller than 0.5%, however, this value can increase to ~2% when covering an active region with 5.0 times the quiet star brightness temperature.
The long-term evolution of stellar activity
Authors: Gregory Scott G. 
Published: September 2017

AbstractI review the evolution of low-mass stars with outer convective zones over timescales of millions-to-billions of years, from the pre-main sequence to solar-age, ~4.6 Gyr (Bahcallet al.1995; Amelinet al.2010), and beyond. I discuss the evolution of high-energy coronal and chromospheric emission, the links with stellar rotation and magnetism, and the emergence of the rotation-activity relation for stars within young clusters.
Rossby numbers of fully convective and partially convective stars
Authors: Landin Natália R. , Mendes Luiz T. S. 
Published: September 2017

AbstractIn this work, we investigate the stellar magnetic activity in the theoretical point of view, through the use of stellar structure and evolution models. We present theoretical values of convective turnover times and Rossby numbers for low-mass stars, calculated with the ATON stellar structure and evolution code. We concentrate our analysis on fully convective and partially convective stars motivated by recent observations of X-ray emission of slowly rotating fully convective stars, which suggest that the presence of a tachocline is not a central key for magnetic fields generation. We investigate the behavior of the convective turnover time evolution, as well as its radial profile inside the star. A discussion about the location where the convective turnover time is calculated in the stellar interior is also addressed. Our theoretical results are compared to observational data from low-mass stars.
Magnetic fields of weak line T-Tauri stars
Authors: Hill Colin A. ,   the MaTYSSE Collaboration
Published: September 2017

AbstractT-Tauri stars (TTS) are late-type pre-main-sequence (PMS) stars that are gravitationally contracting towards the MS. Those that possess a massive accretion disc are known as classical T-Tauri stars (cTTSs), and those that have exhausted the gas in their inner discs are known as weak-line T-Tauri stars (wTTSs). Magnetic fields largely dictate the angular momentum evolution of TTS and can affect the formation and migration of planets. Thus, characterizing their magnetic fields is critical for testing and developing stellar dynamo models, and trialling scenarios currently invoked to explain low-mass star and planet formation. The MaTYSSE programme (Magnetic Topologies of Young Stars and the Survival of close-in Exoplanets) aims to determine the magnetic topologies of ~30 wTTSs and monitor the long-term topology variability of ~5 cTTSs. We present several wTTSs that have been magnetically mapped thus far (using Zeeman Doppler Imaging), where we find a much wider range of field topologies compared to cTTSs and MS dwarfs with similar internal structures.
Differential rotation of stars with multiple transiting planets
Authors: Netto Yuri , Valio Adriana 
Published: September 2017

AbstractIf a star hosts a planet in an orbit such that it eclipses the star periodically, can be estimated the rotation profile of this star. If planets in multiplanetary system occult different stellar areas, spots in more than one latitude of the stellar disc can be detected. The monitored study of theses starspots in different latitudes allow us to infer the rotation profile of the star. We use the model described in Silva (2003) to characterize the starspots of Kepler-210, an active star with two planets. Kepler-210 is a late K star with an estimated age of 350 ± 50 Myrs, average rotation period of 12.33 days, mass of 0.63 M⊙ and radius of 0.69 R⊙. The planets that eclipses this star have radii of 0.0498 Rs and 0.0635 Rs with orbital periods of 2.4532 ± 0.0007 days and 7.9725 ± 0.0014 days, respectively, where Rs is the star radius.
Solar Radius at Sub-Terahertz Frequencies
Authors: Menezes Fabian , Valio Adriana 
Published: September 2017

AbstractThe visible surface of the Sun, or photosphere, is defined as the solar radius in the optical spectrum range located at 696,000 km (Cox et al. (Ed. 2015)). However, as the altitude increases, the dominant electromagnetic radiation is emitted at other frequencies. Our aim is to measure the solar radius at frequencies of 212 GHz and 405 GHz through out a solar cycle and, therefore, the altitude where these emissions are generated and that variation along the years. Also we tried to verify the the radius dependence on the solar activity cycle, which can be a good indicator of the changes that occur in the atmosphere structure. For this, we used data obtained by the Submillimetric Solar Telescope (SST) created from daily scans made by SST from 1990 to 2015. From these scans a 2D map of the solar disk was constructed. The solar radius is then determined by adjusting a circumference to the points where the brightness is half of the quiet Sun level, which is set as the most common temperature value in the solar map, i.e., the mode of the temperature distribution. Thus, we determined the solar radius at 212 and 405 GHz and the altitude of the emissions respectively. For 212 GHz, we obtained a radius of 976.5”±8” (707±4 Mm), whereas for 405 GHz, we obtained 975.0”±8” (707±5 Mm). optical spectrum range
An Eruptive Complex Solar Flare and Events in its Aftermath
Authors: Luoni M.L. , Francile C. , Mandrini C. H. , Cremades H. 
Published: September 2017

AbstractWe present a study of the M6.6 flare that occurred on 13 February 2011 in AR 11158. The flare was accompanied by a CME and EUV waves. We use multiwavelength observations from the ground: H-alpha Solar Telescope for Argentina (HASTA), and space: Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA), both onboard the Solar and Dynamic Observatory (SDO).
Observable Impacts of Exoplanets on Stellar Hosts – An X-Ray Perspective
Authors: Wolk Scott J. , Pillitteri Ignazio , Poppenhaeger Katja 
Published: September 2017

AbstractSoon after the discovery of hot Jupiters, it was suspected that interaction of these massive bodies with their host stars could give rise to observable signals. We discuss the observational evidence for star-planet interactions (SPI) of tidal and magnetic origin observed in X-rays. Hot Jupiters can significantly impact the activity of their host stars through tidal and magnetic interaction, leading to either increased or decreased stellar activity – depending on the internal structure of the host star and the properties of the hosted planet. We provide several examples of these interactions. In HD 189733, the strongest X-ray flares are preferentially seen in a very restricted range of planetary phases. Hot Jupiters, can also obscure the X-ray signal during planetary transits. Observations of this phenomena have led to the discovery of a thin upper atmospheres in HD 189733A. On the other hand, WASP-18 – an F6 star with a massive hot Jupiter, shows no signs of activity in X-rays or UV. Several age indicators (isochrone fitting, Li abundance) point to a young age (~0.5 – −1.0 Gyr) and thus significant activity was expected. In this system, tidal SPI between the star and the very close-in and massive planet appears to disrupt the surface shear layer and thus nullify the stellar activity.
A new look at sunspot formation using theory and observations
Authors: Losada I. R. , Warnecke J. , Glogowski K. , Roth M. , Brandenburg A. , Kleeorin N. , Rogachevskii I. 
Published: September 2017

AbstractSunspots are of basic interest in the study of the Sun. Their relevance ranges from them being an activity indicator of magnetic fields to being the place where coronal mass ejections and flares erupt. They are therefore also an important ingredient of space weather. Their formation, however, is still an unresolved problem in solar physics. Observations utilize just 2D surface information near the spot, but it is debatable how to infer deep structures and properties from local helioseismology. For a long time, it was believed that flux tubes rising from the bottom of the convection zone are the origin of the bipolar sunspot structure seen on the solar surface. However, this theory has been challenged, in particular recently by new surface observation, helioseismic inversions, and numerical models of convective dynamos. In this article we discuss another theoretical approach to the formation of sunspots: the negative effective magnetic pressure instability. This is a large-scale instability, in which the total (kinetic plus magnetic) turbulent pressure can be suppressed in the presence of a weak large-scale magnetic field, leading to a converging downflow, which eventually concentrates the magnetic field within it. Numerical simulations of forced stratified turbulence have been able to produce strong super-equipartition flux concentrations, similar to sunspots at the solar surface. In this framework, sunspots would only form close to the surface due to the instability constraints on stratification and rotation. Additionally, we present some ideas from local helioseismology, where we plan to use the Hankel analysis to study the pre-emergence phase of a sunspot and to constrain its deep structure and formation mechanism.
The X-ray Light-Curves and CME onset of a M2.5 flare of July 6, 2006
Authors: Mendoza-Torres J. E. , Pérez-León J. E. 
Published: September 2017

AbstractA M2.5 solar flare observed by RHESSI in the 6-100 keV range on July 6, 2006 led to a Coronal Mass Ejection (CME). Two compact sources at 12-100 keV are seen at the beginning of the flare, whose further evolution fits well in a loop. Also, time-profiles of the flare at radio wavelengths are compared. The X-ray light-curves at different bands in the 6-100 keV range and radio time profiles show some peaks superimposed on smooth variations. The aim of this work is to compare the X-ray light-curves, of fluxes integrated over the whole source, with the physical parameters of the sources of the flare. Yashiro and Gopalswamy (2009) have found that the fraction of flares that produce CME increases with the flare energy. Here, we look for the characteristics of an M2.5 flare that could make it a generator of a CME. The idea is, in future works, to look in the light-curves of similar flares at other stars for these features. It is found that the CME onset takes place around the time when an X-ray source at 12-25 keV of Chromospheric evaporation stagnates at the loop apex, before the main peak at the light-curve at 25-50 keV and at the radio emission curves. Probably, the amount of evaporated plasma could play some role in triggering the CME.
The Faint Young Sun and Faint Young Stars Paradox
Authors: Martens Petrus C. 
Published: September 2017

AbstractThe purpose of this paper is to explore a resolution for the Faint Young Sun Paradox that has been mostly rejected by the community, namely the possibility of a somewhat more massive young Sun with a large mass loss rate sustained for two to three billion years. This would make the young Sun bright enough to keep both the terrestrial and Martian oceans from freezing, and thus resolve the paradox. It is found that a large and sustained mass loss is consistent with the well observed spin-down rate of Sun-like stars, and indeed may be required for it. It is concluded that a more massive young Sun must be considered a plausible hypothesis.
Interaction of extra solar planets with their host star
Authors: Silva Douglas , Valio Adriana 
Published: September 2017

AbstractTransit is the passage of the planet in front of its star. During one of these transits, the planet may occult a spot on the photosphere of the star, causing small variations in its light curve. By detecting the same spot in a later transit, it is possible to estimate the stellar rotation period. The comparison between the rotation period of star at the equator and the planets orbital period showed the existence of resonances between these periods. Two types of mechanisms are proposed in the literature: electromagnetic interaction between the stellar and planetary fields and gravitational interaction. Our results have shown that for planets CoRoT-2b, CoRoT-5b and CoRoT-8b, tidal effects seem to dominate, whereas for planets CoRoT-4b and CoRoT-6b electromagnetic interaction dominates over tidal effects. A distinct characteristic of these last two systems is that the orbital period is larger than the rotation period of the star.
What can He II 304 Å tell us about transient seismic emission from solar flares?
Authors: Lindsey C. , Donea A. C. 
Published: September 2017

AbstractAfter neary 20 years since their discovery by Kosovichev and Zharkova, the mechanics of the release of seismic transients into the solar interior from some flares remain a mystery. Seismically emissive flares invariably show the signatures of intense chromosphere heating consistent with pressure variations sufficient to drive seismic transients commensurate with helioseismic observations—under certain conditions. Magnetic observations show the signatures of apparent magnetic changes, suggesting Lorentz-force transients that could likewise drive seismic transients—similarly subject to certain conditions. But, the diagnostic signatures of both of these prospective drivers are apparent over vast regions from which no significant seismic emission emanates. What distinguishes the source regions of transient seismic emission from the much vaster regions that show the signatures of both transient heating and magnetic variations but are acoustically unproductive? Observations of acoustically active flares in He II 304 Å by the Atomospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO) offer a promising new resource with which to address this question.