The Chandra X-Ray Optics

Significant advances in science always take place when the state of the art in instrumentation improves dramatically. NASA's Chandra X-Ray Observatory represents such an advance. Launched in July of 1999, Chandra is an observatory designed to study the x-ray emission from all categories of astronomical objects --- from comets, planets, and normal stars to quasars, galaxies, and clusters of galaxies. At the heart of this observatory is the precision X-Ray optic that has been vital for Chandra's outstanding success and which features an angular resolution improved by an order of magnitude compared to its forerunners. The Chandra mission is now entering its 13-th year of operation. Given that the Observatory was designed for a minimum of 3 years of operation testifies to its robust and carefully thought out design. We review the design and construction of the remarkable telescope, present examples of its usage for astronomy and astrophysics, and speculate upon the future.Comment: 14 pages, 11 figures, invited paper for Optical Engineerin

Predictors of Parent Engagement Based on Child Care Providers’ Perspectives

Objective: Determine the predictors of child care providers’ parent engagement regarding child nutrition in child care centers (CCCs) and family child care homes (FCCHs). Design: Cross-sectional. Setting: Child care centers and FCCHs. Participants: Child care center directors (n = 337) and FCCH providers (n = 1,153) completed a self-administered survey. Main outcome measures: Fifteen variables were examined as predictors for parent engagement: providers’ perceived barriers to communication, participation in Go Nutrition and Physical Self-Assessment in Child Care, National Association for the Education of Young Children accreditation, participation in Quality Ratings and Improvement Systems, feeding practices, and professional development. Analysis: Structural equation modeling examined the relation between variables for CCCs and for FCCHs. Results: For CCCs, NAEYC accreditation, providers’ perceived barriers regarding parents’ cultural beliefs about food, parents not liking the taste of healthy foods, and parents prioritizing other food-related topics over healthy eating significantly predicted parent engagement. For FCCHs, participation in Go Nutrition and Physical Self-Assessment in Child Care, perceiving parents to be busy, not wanting to offend parents, and practicing family-style dining were significantly related to parent engagement. For both CCCs and FCCHs, professional development regarding child nutrition was related to parent engagement. Conclusions and implications: Focusing professional development on child care contexts and addressing providers’ perceived barriers may improve parent engagement

‘Read for Nutrition’ programme improves preschool children’s liking and consumption of target vegetable

Objective: To determine whether the ‘Read for Nutrition’ programme would increase liking and consumption of broccoli (a target vegetable) in preschool children and test acceptability and practicality of the programme. Design: Pilot pre-post intervention study, where childcare teachers received training and coaching followed by reading the book ‘Monsters Don’t Eat Broccoli’ multiple times with the children during a three-week intervention. Setting: Five classrooms of Educare, Lincoln, Nebraska in 2018. Participants: Sixty-nine (11 to 16 children per classroom) preschool-aged children and sixteen teachers (minimum, three per classroom). Results: Average total consumption of broccoli increased 35 % (0·14 ounces or 0·05th cup) after the ‘Read for Nutrition’ programme (t = 2·66; P = 0·01; 95 % CIs (0·035, 0·246)) for all children. Proportional consumption increased for children who received ≥ five exposures to the book (t46 = 2·77; P = 0·008). Exposures to the book predicted proportional consumption (β = 0·365; P = 0·002). Liking of broccoli increased (W69 = 2·2, P = 0·03) as well. Teachers rated the programme as acceptable, practical and enjoyable to children and to themselves. Conclusions: Programmes such as ‘Read for Nutrition’ have the potential to improve children’s vegetable liking and consumption in early care and education settings with only book readings and no exposure to a real vegetable

The Three-Dimensional Structure of Cassiopeia A

We used the Spitzer Space Telescope's Infrared Spectrograph to map nearly the entire extent of Cassiopeia A between 5-40 micron. Using infrared and Chandra X-ray Doppler velocity measurements, along with the locations of optical ejecta beyond the forward shock, we constructed a 3-D model of the remnant. The structure of Cas A can be characterized into a spherical component, a tilted thick disk, and multiple ejecta jets/pistons and optical fast-moving knots all populating the thick disk plane. The Bright Ring in Cas A identifies the intersection between the thick plane/pistons and a roughly spherical reverse shock. The ejecta pistons indicate a radial velocity gradient in the explosion. Some ejecta pistons are bipolar with oppositely-directed flows about the expansion center while some ejecta pistons show no such symmetry. Some ejecta pistons appear to maintain the integrity of the nuclear burning layers while others appear to have punched through the outer layers. The ejecta pistons indicate a radial velocity gradient in the explosion. In 3-D, the Fe jet in the southeast occupies a "hole" in the Si-group emission and does not represent "overturning", as previously thought. Although interaction with the circumstellar medium affects the detailed appearance of the remnant and may affect the visibility of the southeast Fe jet, the bulk of the symmetries and asymmetries in Cas A are intrinsic to the explosion.Comment: Accepted to ApJ. 54 pages, 21 figures. For high resolution figures and associated mpeg movie and 3D PDF files, see http://homepages.spa.umn.edu/~tdelaney/pape

The X-ray Spectrum of the Vela Pulsar Resolved with Chandra

We report the results of the spectral analysis of two observations of the Vela pulsar with the Chandra X-ray observatory. The spectrum of the pulsar does not show statistically significant spectral lines in the observed 0.25-8.0 keV band. Similar to middle-aged pulsars with detected thermal emission, the spectrum consists of two distinct components. The softer component can be modeled as a magnetic hydrogen atmosphere spectrum - for the pulsar magnetic field $B=3\times 10^{12}$ G and neutron star mass $M=1.4 M_\odot$ and radius $R^\infty =13$ km, we obtain \tef^\infty =0.68\pm 0.03 MK, $L_{\rm bol}^\infty = (2.6\pm 0.2)\times 10^{32}$ erg s$^{-1}$, $d=210\pm 20$ pc (the effective temperature, bolometric luminosity, and radius are as measured by a distant observer). The effective temperature is lower than that predicted by standard neutron star cooling models. A standard blackbody fit gives $T^\infty =1.49\pm 0.04$ MK, $L_{\rm bol}^\infty=(1.5\pm 0.4)\times 10^{32} d_{250}^2$ erg s$^{-1}$ ($d_{250}$ is the distance in units of 250 pc); the blackbody temperature corresponds to a radius, $R^\infty =(2.1\pm 0.2) d_{250}$ km, much smaller than realistic neutron star radii. The harder component can be modeled as a power-law spectrum, with parameters depending on the model adopted for the soft component - $\gamma=1.5\pm 0.3$, $L_x=(1.5\pm 0.4)\times 10^{31} d_{250}^2$ erg s$^{-1}$ and $\gamma=2.7\pm 0.4$, $L_x=(4.2\pm 0.6)\times 10^{31} d_{250}^2$ erg s$^{-1}$ for the hydrogen atmosphere and blackbody soft component, respectively ($\gamma$ is the photon index, $L_x$ is the luminosity in the 0.2--8 keV band). The extrapolation of the power-law component of the former fit towards lower energies matches the optical flux at $\gamma\simeq 1.35$--1.45.Comment: Submitted to ApJ, three figures; color figure 1 can be found at http://www.xray.mpe.mpg.de/~zavlin/pub_list.htm

Nutrition Education Resources in North Carolina–Based Head Start Preschool Programs: Administrator and Teacher Perceptions of Availability and Use

Objective: The purpose of this study was to provide new insight into common barriers to the availability and use of nutrition education (NE) resources in Head Start preschool programs based on administrator and teacher perceptions. Methods: In-depth, semistructured phone interviews (n = 63) were conducted with administrators (n = 31) and teachers (n = 32) from North Carolina–based Head Start programs. Interviews were audio-recorded and transcribed verbatim. Data were analyzed qualitatively using content analysis to identify common themes. Results: Five emergent themes were identified within the areas of NE resource availability and use and barriers to NE resource availability and use. Participants expressed desire for greater organization of existing NE material resources, increased community support, and professional development opportunities for teachers specific to NE. Funding and time constraints were reported as affecting NE resources. Conclusions and Implications: Creative strategies for addressing NE resource availability and use and barriers (e.g., NE integration with educational standards) in Head Start are needed

Comparison of Parent and Child Ratings of Fruit and Vegetable Liking to Assess Parent Accuracy as Proxy Reporters

This study examined the accuracy of parent-report child fruit/ vegetable (FV) liking. Child/parent dyads (n = 24) were recruited from six Head Start preschools in North Carolina. Liking for 10 FVs was assessed using a validated pictorial tool for children; a similar scale was used for parents. Negative relationships were observed between parent/child for one fruit (grapes) and one vegetable (broccoli). Positive relationships were observed among oranges, grapes, and overall fruit rankings. Parents tended to rank children’s liking of fruits higher than their children, while children ranked liking vegetables higher. Findings suggest parents may not be accurate respondents for preschool children’s FV liking

Comparison of Parent and Child Ratings of Fruit and Vegetable Liking to Assess Parent Accuracy as Proxy Reporters

This study examined the accuracy of parent-report child fruit/ vegetable (FV) liking. Child/parent dyads (n = 24) were recruited from six Head Start preschools in North Carolina. Liking for 10 FVs was assessed using a validated pictorial tool for children; a similar scale was used for parents. Negative relationships were observed between parent/child for one fruit (grapes) and one vegetable (broccoli). Positive relationships were observed among oranges, grapes, and overall fruit rankings. Parents tended to rank children’s liking of fruits higher than their children, while children ranked liking vegetables higher. Findings suggest parents may not be accurate respondents for preschool children’s FV liking

Eating Smart and Moving More for Head Start: A Pilot Study

Our study examined the relationship between improved personal health behaviors of Head Start teachers’ and the promotion of positive health behaviors in their classroom. Thirty-three Head Start teachers across 7 centers received six 30-minute nutrition education lessons. Dietary intake, physical activity, and self-efficacy for promoting positive health behaviors in the classroom were measured at baseline and post-intervention. Significant improvements were observed for dietary intake and physical activity. Self-efficacy for promoting health behaviors in the classroom did not significantly improve. Additional education is needed to improve health promotion practices. Lessons learned contributed to program refinement. Implications for Extension are discussed