bluuebunny/crossref_metadata_2025_split huggingface dataset:
Household food security is associated with growth of infants and young children in rural Bangladesh
Authors: Saha Kuntal K , Frongillo Edward A , Alam Dewan S , Arifeen Shams E , Persson Lars Å , Rasmussen Kathleen M 
Published: February 2009

AbstractObjectiveDespite a strong relationship between household food security and the health and nutritional status of adults and older children, the association of household food security with the growth of infants and young children has not been adequately studied, particularly in developing countries. We examined the association between household food security and subsequent growth of infants and young children in rural Bangladesh.DesignWe followed 1343 children from birth to 24 months of age who were born in the Maternal and Infant Nutrition Intervention in Matlab (MINIMat) study in rural Bangladesh. A food security scale was created from data collected on household food security from the mothers during pregnancy. Data on weight and length were collected monthly in the first year and quarterly in the second year of life. Anthropometric indices were calculated relative to the 2006 WHO child growth standards. Growth trajectories were modelled using multilevel models for change controlling for possible confounders.ResultsHousehold food security was associated (P < 0·05) with greater subsequent weight and length gain in this cohort. Attained weight, length and anthropometric indices from birth to 24 months were higher (P < 0·001) among those who were in food-secure households. Proportions of underweight and stunting were significantly (P < 0·05) lower in food-secure households.ConclusionsThese results suggest that household food security is a determinant of child growth in rural Bangladesh, and that it may be necessary to ensure food security of these poor rural households to prevent highly prevalent undernutrition in this population and in similar settings elsewhere in the world.
Height differences and the associations between food insecurity, percentage body fat and BMI among men and women
Authors: Tayie Francis A , Zizza Claire A 
Published: February 2009

AbstractObjectiveThe present study examined the associations between adult food insecurity (FI) and percentage body fat (%BF) and BMI, stratified by height (HT).Design, setting and subjects%BF, HT and BMI of 2117 men and 1909 women in the National Health and Nutrition Examination Survey 1999–2002 were analysed in relation to adult food security status using multiple regression procedures.ResultsCompared with the fully food-secure, men’s %BF, BMI and HT were lower as FI intensified. Marginal food security among women was associated with 1·3 cm shorter HT, P = 0·016. Marginal food security among women who were below median HT was associated with about 2·0 kg/m2 higher BMI, P = 0·042. %BF was not associated with FI among women.ConclusionsFI is associated with shorter HT and lower %BF and BMI in men. Women’s HT should be considered in the reported associations between FI and higher BMI.
Vitamin D deficiency in early childhood: prevalent in the sunny South Pacific
Authors: Grant Cameron C , Wall Clare R , Crengle Sue , Scragg Robert 
Published: February 2009

AbstractObjectiveTo estimate the prevalence of and risk factors for vitamin D deficiency in young urban children in Auckland, New Zealand, where there is no routine vitamin D supplementation.DesignA random sample of urban children. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D <27·5 nmol/l (<11 ng/ml). Logistic regression analysis was used to calculate odds ratios and, from these, relative risks (RR) and 95 % confidence intervals were estimated.SettingAuckland, New Zealand (36°52′S), where the daily vitamin D production by solar irradiation varies between summer and winter at least 10-fold.SubjectsChildren aged 6 to 23 months enrolled from 1999 to 2002.ResultsVitamin D deficiency was present in forty-six of 353 (10 %; 95 % CI 7, 13 %). In a multivariate model there was an increased risk of vitamin D deficiency associated with measurement in winter or spring (RR = 7·24, 95 % CI 1·55, 23·58), Pacific ethnicity (RR = 7·60, 95 % CI 1·80, 20·11), not receiving any infant or follow-on formula (RR = 5·69, 95 % CI 2·66, 10·16), not currently receiving vitamin supplements (RR = 5·32, 95 % CI 2·04, 11·85) and living in a more crowded household (RR = 2·36, 95 % CI 1·04, 4·88).ConclusionsVitamin D deficiency is prevalent in early childhood in New Zealand. Prevalence varies with season and ethnicity. Dietary factors are important determinants of vitamin D status in this age group. Vitamin D supplementation should be considered as part of New Zealand’s child health policy.
Screen time and adiposity in adolescents in Mexico
Authors: Lajous Martín , Chavarro Jorge , Peterson Karen E , Hernández-Prado Bernardo , Cruz-Valdéz Aurelio , Hernández-Ávila Mauricio , Lazcano-Ponce Eduardo 
Published: February 2009

AbstractObjectiveTo assess the association of time spent viewing television, videos and video games with measures of fat mass (BMI) and distribution (triceps and subscapular skinfold thicknesses (TSF, SSF)).DesignCross-sectional validated survey, self-administered to students to assess screen time (television, videos and video games) and lifestyle variables. Trained personnel obtained anthropometry. The association of screen time with fat mass and distribution, stratified by sex, was modelled with multivariable linear regression analysis, adjusting for potential confounders and correlation of observations within schools.SettingState of Morelos, Mexico.SubjectsMales (n3519) and females (n5613) aged 11 to 18 years attending urban and rural schools in Morelos.ResultsIn males, screen time of >5 h/d compared with <2 h/d was significantly associated with a 0·13 (95 % CI 0·04, 0·23) higher BMIZ-score, 0·73 mm (95 % CI 0·24, 1·22) higher SSF and 1·08 mm (95 % CI 0·36, 1·81) higher TSF. The positive association of screen time with SSF was strongest in males aged 11–12 years. Sexual maturity appeared to modify the association in females; a positive association between screen time and SSF was observed in those who had not undergone menarche (Pfor trend = 0·04) but not among sexually mature females (Pfor trend = 0·75).ConclusionScreen time is associated with fat mass and distribution among adolescent males in Mexico. Maturational tempo appears to affect the relationship of screen time with adiposity in boys and girls. Findings suggest that obesity preventive interventions in the Mexican context should explore strategies to reduce screen time among youths in early adolescence.
Search for Transiting Exoplanets with HATNet
Authors: Bakos G. Á. , Noyes R. W. , Kovács G. , Latham D. W. , Torres G. , Sasselov D. , Pál A. , Sipőcz B. , Kovács Gábor 
Published: February 2009

AbstractHATNet is a network of six identical, fully automated wide field telescopes, four of which are located in Arizona, and two at Hawaii. The purpose of the network is to search for transiting extrasolar planets around relatively bright stars (8 <I< 12). The longitudinal coverage of 3.5 hours greatly enhances transit detection efficiency. HATNet has been operational since 2004, and has taken more than 1/2 million science frames at 5-min integrations, covering about 7% of the sky. Photometric precision reaches 3mmag rms at 5.5 min cadence atI≈ 8, and is 1% atI≈ 11.3. Hundreds of transitcandidateshave been detected in the data, and have been subject to vigorous follow-up by various 1m-class facilities, both spectroscopy and follow-up photometry. A fraction of the candidates that have survived these steps as not being false alarms have been observed by high resolution and precision spectrographs (primarily Keck/HIRES), to confirm their planetary nature and characterize their properties. So far nine transiting planets have been reported, making HATNet a very successful survey.
Transits against Fainter Stars: The Power of Image Deconvolution
Authors: Sackett Penny D. , Gillon Michaël , Bayliss Daniel D. R. , Weldrake David T. F. , Tingley Brandon 
Published: February 2009

AbstractCompared to bright star searches, surveys for transiting planets against fainter (V = 12–18) stars have the advantage of much higher sky densities of dwarf star primaries, which afford easier detection of small transiting bodies. Furthermore, deep searches are capable of probing a wider range of stellar environments. On the other hand, for a given spatial resolution and transit depth, deep searches are more prone to confusion from blended eclipsing binaries. We present a powerful mitigation strategy for the blending problem that includes the use of image deconvolution and high-resolution imaging. The techniques are illustrated with Lupus-TR-3 and very recent IR imaging with PANIC on Magellan. The results are likely to have implications for the CoRoT and KEPLER missions designed to detect transiting planets of terrestrial size.
Predicting the Yields of Photometric Surveys for Transiting Planets
Authors: Beatty Thomas G. 
Published: February 2009

AbstractObserving extrasolar planetary transits is one of the only ways that we may infer the masses and radii of planets outside the Solar System. As such, the detections made by photometric transit surveys are one of the only foreseeable ways that the areas of planetary interiors, system dynamics, migration, and formation will acquire more data. Predicting the yields of these surveys therefore serves as a useful statistical tool. Predictions allows us to check the efficiency of transit surveys (“are we detecting all that we should?”) and to test our understanding of the relevant astrophysics (“what parameters affect predictions?”). Furthermore, just the raw numbers of how many planets will be detected by a survey can be interesting in its own right. Here, we look at two different approaches to modeling predictions (forward and backward), and examine three different transit surveys (TrES, XO, and Kepler). In all cases, making predictions provides valuable insight into both extrasolar planets and the surveys themselves, but this must be tempered by an appreciation of the uncertainties in the statistical cut-offs used by the transit surveys.
Searching for the secondary eclipse of CoRoT-Exo-2b and its transit timing variations
Authors: Alonso Roi , Aigrain Suzanne , Pont Frédéric , Mazeh Tsevi ,   the CoRoT Exoplanet Science Team
Published: February 2009

AbstractWith more than 80 transits observed in the CoRoT lightcurve with a cadence of 32 s, CoRoT-Exo-2b provides an excellent case to search for the secondary eclipse of the planet, with an expected signal of less than 10−4 in relative flux. The activity of the star causes a modulation on the flux that makes the detection of this signal challenging. We describe the technique used to seek for the secondary eclipse, that leads to a tentative 2.5σ detection of a 5.5×10−5 eclipse. If the effect of the spots are not taken into account, the times of transit centers will also be affected. They could lead to an erroneous detection of periodic transit timing variations of ~20 s and with a 7.45 d period. By measuring the transit central times at different depths of the transit (transit bisectors), we show that there are no such periodic variations in the CoRoT-Exo-2b O-C residuals larger than ~10 s.
Towards the Albedo of an Exoplanet: MOST Satellite Observations of Bright Transiting Exoplanetary Systems
Authors: Rowe Jason F. , Matthews Jaymie M. , Seager Sara , Sasselov Dimitar , Kuschnig Rainer , Guenther David B. , Moffat Anthony F. J. , Rucinski Slavek M. , Walker Gordon A. H. , Weiss Werner W. 
Published: February 2009

AbstractThe Canadian MOST satellite is a unique platform for observations of bright transiting exoplanetary systems. Providing nearly continuous photometric observations for up to 4 weeks, MOST can produce important observational data to help us learn about the properties of exosolar planets. We review our current observations of HD 209458 and HD 189733 with implications for the albedo and our progress towards detecting reflected light from an exoplanet.
What to Expect from Transiting Multiplanet Systems
Authors: Fabrycky Daniel C. 
Published: February 2009

AbstractSo far radial velocity measurements have discovered ~25 stars to host multiple planets. The statistics imply that many of the known hosts of transiting planets should have additional planets, yet none have been solidly detected. They will be soon, via complementary search methods of RV, transit-time variations of the known planet, and transits of the additional planet. When they are found, what can transit measurements add to studies of multiplanet dynamical evolution? First, mutual inclinations become measurable, for comparison to the solar system's disk-like configuration. Such measurements will give important constraints to planet-planet scattering models, just as the radial velocity measurements of eccentricity have done. Second, the Rossiter-McLaughlin effect measures stellar obliquity, which can be modified by two-planet dynamics with a tidally evolving inner planet. Third, transit-time variations are exquisitely sensitive to planets in mean motion resonance. Two planets differentially migrating in the disk can establish such resonances, and tidal evolution of the planets can break them, so the configuration and frequency of these resonances as a function of planetary parameters will constrain these processes.
Transits and secondary eclipses of HD 189733 with Spitzer
Authors: Agol Eric , Cowan Nicolas B. , Bushong James , Knutson Heather , Charbonneau David , Deming Drake , Steffen Jason H. 
Published: February 2009

AbstractWe present limits on transit timing variations and secondary eclipse depth variations at 8 microns with the Spitzer Space Telescope IRAC camera. Due to the weak limb darkening in the infrared and uninterrupted observing, Spitzer provides the highest accuracy transit times for this bright system, in principle providing sensitivity to secondary planets of Mars mass in resonant orbits. Finally, the transit data provides tighter constraints on the wavelength-dependent atmospheric absorption by the planet.
Planetary Transits and Tidal Evolution
Authors: Jackson Brian , Barne Rory , Greenberg Richard 
Published: February 2009

AbstractTransiting planets are generally close enough to their host stars that tides may govern their orbital and thermal evolution. We present calculations of the tidal evolution of recently discovered transiting planets and discuss their implications. The tidal heating that accompanies this orbital evolution can be so great that it controls the planet's physical properties and may explain the large radii observed in several cases, including, for example, TrES-4. Also, since a planet's transit probability depends on its orbit, it evolves due to tides. Current values depend sensitively on the physical properties of the star and planet, as well as on the system's age. As a result, tidal effects may introduce observational biases in transit surveys, which may already be evident in current observations. Transiting planets tend to be younger than non-transiting planets, an indication that tidal evolution may have destroyed many close-in planets. Also the distribution of the masses of transiting planets may constrain the orbital inclinations of non-transiting planets.
The extrasolar planet atmosphere and exosphere: Emission and transmission spectroscopy
Authors: Tinetti Giovanna , Beaulieu Jean-Philippe 
Published: February 2009

AbstractWe have now entered a phase of extrasolar planets characterization: probing their atmospheres for molecules, constraining their horizontal and vertical temperature profiles and estimating the contribution of clouds and hazes. We review here the current situation with ground-based and space-based observations, and present the transmission spectra of HD189733b in the spectral range 0.5-24 microns.
Spectrum and atmosphere models of irradiated transiting giant planets
Authors: Hubeny Ivan , Burrows Adam 
Published: February 2009

AbstractWe show that a consistent fit to observed secondary eclipse data for several strongly irradiated transiting planets demands a temperature inversion (stratosphere) at altitude. Such a thermal inversion significantly influences the planet/star contrast ratios at the secondary eclipse, their wavelength dependences, and, importantly, the day-night flux contrast during a planetary orbit. The presence of the thermal inversion/stratosphere seems to roughly correlate with the stellar flux at the planet. Such temperature inversions might be caused by an upper-atmosphere absorber whose exact nature is still uncertain.
The Atmospheres of Extrasolar Super-Earths
Authors: Miller-Ricci Eliza , Seager Sara , Sasselov Dimitar 
Published: February 2009

AbstractExtrasolar super-Earths (1-10 M⊕) are likely to exist with a wide range of atmospheres. While a number of these planets have already been discovered through radial velocities and microlensing, it will be the discovery of the firsttransitingsuper-Earths that will open the door to a variety of follow-up observations aimed at characterizing their atmospheres. Super-Earths may fill a large range of parameter space in terms of their atmospheric composition and mass. Specifically, some of these planets may have high enough surface gravities to be able to retain large hydrogen-rich atmosphseres, while others will have lost most of their hydrogen to space over the planet's lifetime, leaving behind an atmosphere more closely resembling that of Earth or Venus. The resulting composition of the super-Earth atmosphere will therefore depend strongly on factors such as atmospheric escape history, outgassing history, and the level of stellar irradiation that it receives. Here we present theoretical models of super-Earth emission and transmission spectra for a variety of possible outcomes of super-Earth atmospheric composition ranging from hydrogen-rich to hydrogen-poor. We focus on how observations can be used to differentiate between the various scenarios and constrain atmospheric composition.
Radiative Hydrodynamical Studies of Irradiated Atmospheres
Authors: Dobbs-Dixon Ian 
Published: February 2009

AbstractTransiting planets provide a unique opportunity to study the atmospheres of extra-solar planets. Radiative hydrodynamical models of the atmosphere provide a crucial link between the physical characteristics of the atmosphere and the observed properties. Here I present results from 3D simulations which solve the full Navier-Stokes equations coupled to a flux-limited diffusion treatment of radiation transfer. Variations in opacity amongst models leads to a variation in the temperature differential across the planet, while atmospheric dynamics becomes much more variable at longer orbital periods. I also present 3D radiative simulations illustrating the importance of distinguishing between optical and infrared opacities.
KEPLER: Search for Earth-Size Planets in the Habitable Zone
Authors: Borucki William , Koch David , Batalha Natalie , Caldwell Douglas , Christensen-Dalsgaard Jorgen , Cochran William D. , Dunham Edward , Gautier Thomas N. , Geary John , Gilliland Ronald , Jenkins Jon , Kjeldsen Hans , Lissauer Jack J. , Rowe Jason 
Published: February 2009

AbstractTheKepler Missionis a space-based mission whose primary goal is to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for patterns of transits with a differential photometric precision of 20 ppm at V = 12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.This paper provides a short overview of the mission, a brief history of the mission development, expected results, new investigations by the recently chosen Participating Scientists, and the plans for the Guest Observer and Astrophysical Data Programs.
The NASA EPOXI mission of opportunity to gather ultraprecise photometry of known transiting exoplanets
Authors: Christiansen Jessie L. , Charbonneau David , A'Hearn Michael F. , Deming Drake , Holman Matthew J. , Ballard Sarah , Weldrake David T. F. , Barry Richard K. , Kuchner Marc J. , Livengood Timothy A. , Pedelty Jeffrey , Schultz Alfred , Hewagama Tilak , Sunshine Jessica M. , Wellnitz Dennis D. , Hampton Don L. , Lisse Carey M. , Seager Sara , Veverka Joseph F. 
Published: February 2009

AbstractThe NASA Discovery mission EPOXI, utilizing the Deep Impact flyby spacecraft, comprises two phases: EPOCh (Extrasolar Planet Observation and Characterization) and DIXI (Deep Impact eXtended Investigation). With EPOCh, we use the 30-cm high resolution visible imager to obtain ultraprecise photometric light curves of known transiting planet systems. We will analyze these data for evidence of additional planets, via transit timing variations or transits; for planetary moons or rings; for detection of secondary eclipses and the constraint of geometric planetary albedos; and for refinement of the system parameters. Over a period of four months, EPOCh observed four known transiting planet systems, with each system observed continuously for several weeks. Here we present an overview of EPOCh, including the spacecraft and science goals, and preliminary photometry results.
Measurements of Stellar Properties through Asteroseismology: A Tool for Planet Transit Studies
Authors: Kjeldsen Hans , Bedding Timothy R. , Christensen-Dalsgaard Jørgen 
Published: February 2009

AbstractOscillations occur in stars of most masses and essentially all stages of evolution. Asteroseismology is the study of the frequencies and other properties of stellar oscillations, from which we can extract fundamental parameters such as density, mass, radius, age and rotation period. We present an overview of asteroseismic analysis methods, focusing on how this technique may be used as a tool to measure stellar properties relevant to planet transit studies. We also discuss details of the Kepler Asteroseismic Investigation – the use of asteroseismology on the Kepler mission in order to measure basic stellar parameters. We estimate that applying asteroseismology to stars observed by Kepler will allow the determination of stellar mean densities to an accuracy of 1%, radii to 2–3%, masses to 5%, and ages to 5–10% of the main-sequence lifetime. For rotating stars, the angle of inclination can also be determined.
The WHAT Project
Authors: Shporer A. , Bakos G. Á. , Mazeh T. , Kovács G. , Sipőcz B. 
Published: February 2009

AbstractWHAT is a small-aperture short focal length automated telescope with an 8.2° × 8.2° field of view, located at the Wise Observatory, Israel. The system is similar to the HATNet telescopes and is aimed at searching for transiting extrasolar planets and variable objects. Operational since 2004, WHAT has accumulated ~100000 exposures of several fields and was part of the discovery of the transiting planet HD147506b. Further description of WHAT can be found at: http://wise-obs.tau.ac.il/~what.
TEST The Tautenburg Exoplanet Search Telescope
Authors: Eigmüller Philipp , Eislöffel Jochen 
Published: February 2009

AbstractThe Tautenburg Exoplanet Search Telescope (TEST) is a robotic telescope system. The telescope uses a folded Schmidt Camera with a 300mm main mirror. The focal length is 940mm and it gives a 2.2° × 2.2° field of view. Dome, mount, and CCD cameras are controlled by a software bundle made by Software Bisque. The automation of the telescope includes selection of the night observing program from a given framework, taking darks and skyflats, field identification, guiding, data taking, and archiving. For the search for transiting exoplanets and variable stars an automated psf photometry based on IRAF and a lightcurve analysis based on ESO-Midas are conducted. The images and the results are managed using a PostgreSQL database.