98 research outputs found

    Incidence of Behavior Problems in Toddlers and Preschool Children from Families Living in Poverty

    Get PDF
    Few studies have examined the incidence of behavior problems in toddlers and preschool children from families living in poverty. The available research suggests behavior problems occur at higher rates in children living in poverty and may have long-term negative outcomes if not identified and properly treated. This study included an ethnically representative sample of 357 children, five years of age and younger, from a diverse, low-income, urban area. All families’ incomes met the federal threshold for living in poverty. Behavior problems were assessed by parent report through a questionnaire specifically designed for low-income families. Boys and younger children were reported as demonstrating a higher rate of externalizing behaviors than girls and older children. The overall rate of children scoring at least one standard deviation above the sample\u27s mean for challenging behaviors was 17.4% and was not related to the child\u27s gender, age or ethnicity. This study also sampled children\u27s positive behaviors, which is unique in studies of behavior problems. Gender and age were not related to the frequency of reported positive behaviors. Ethnicity did influence scores on the positive scale. African American children appeared to present their parents more difficulty on items reflecting cooperative behaviors than Caucasian or Latino children. The implications of the study are discussed based on the recognized need for universal screening of behavior problems in young children and the small number professional training programs targeting the identification and treatment of early childhood behavior problems, despite the availability of evidence-based treatment programs tailored to young children in low-income families

    Using Group Model Building to Understand Factors That Influence Childhood Obesity in an Urban Environment

    Get PDF
    Background: Despite increased attention, conventional views of obesity are based upon individual behaviors, and children and parents living with obesity are assumed to be the primary problem solvers. Instead of focusing exclusively on individual reduction behaviors for childhood obesity, greater focus should be placed on better understanding existing community systems and their effects on obesity. The Milwaukee Childhood Obesity Prevention Project is a community-based coalition established to develop policy and environmental change strategies to impact childhood obesity in Milwaukee, Wisconsin. The coalition conducted a Group Model Building exercise to better understand root causes of childhood obesity in its community. Methods: Group Model Building is a process by which a group systematically engages in model construction to better understand the systems that are in place. It helps participants make their mental models explicit through a careful and consistent process to test assumptions. This process has 3 main components: (1) assembling a team of participants; (2) conducting a behavior-over-time graphs exercise; and (3) drawing the causal loop diagram exercise. Results: The behavior-over-time graph portion produced 61 graphs in 10 categories. The causal loop diagram yielded 5 major themes and 7 subthemes. Conclusions: Factors that influence childhood obesity are varied, and it is important to recognize that no single solution exists. The perspectives from this exercise provided a means to create a process for dialogue and commitment by stakeholders and partnerships to build capacity for change within the community

    Clusters at Half Hubble Time: Galaxy Structure and Colors in RXJ0152.7-1357 and MS1054-03

    Full text link
    We study the photometric and structural properties of spectroscopically confirmed members in the two massive X-ray--selected z=0.83 galaxy clusters MS1054-03 and RXJ0152-1357 using three-band mosaic imaging with the Hubble Space Telescope Advanced Camera for Surveys. The samples include 105 and 140 members of MS1054-03 and RXJ0152-1357, respectively, with ACS F775W magnitude < 24.0. We develop a promising new structural classification method, based on a combination of the best-fit Sersic indices and the normalized root-mean-square residuals from the fits; the resulting classes agree well with the visual ones, but are less affected by galaxy orientation. We examine the color--magnitude relations in detail and find that the color residuals correlate with the local mass density measured from our weak lensing maps; we identify a threshold density of Σ≈0.1\Sigma \approx 0.1, in units of the critical density, above which the star formation appears to cease. For RXJ0152-1357, we also find a trend in the color residuals with velocity, resulting from an offset of about 980 km/s in the mean redshifts of the early- and late-type galaxies. Analysis of the color--color diagrams indicates that a range of star formation time-scales are needed to reproduce the loci of the galaxy colors. We also identify some cluster galaxies whose colors can only be explained by large amounts, AV≈1A_V \approx 1 mag, of internal dust extinction. [Abstract shortened]Comment: 30 pages, emulateapj format; 23 figures, many in color. Accepted by ApJ; scheduled for the 10 June 2006 issue. Some figures degraded; for a higher resolution version, see: http://astro.wsu.edu/blakeslee/z1clusters

    ACS Observations of a Strongly Lensed Arc in a Field Elliptical

    Full text link
    We report the discovery of a strongly lensed arc system around a field elliptical galaxy in Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) images of a parallel field observed during NICMOS observations of the HST Ultra-Deep Field. The ACS parallel data comprise deep imaging in the F435W, F606W, F775W, and F850LP bandpasses. The main arc is at a radius of 1.6 arcsec from the galaxy center and subtends about 120 deg. Spectroscopic follow-up at Magellan Observatory yields a redshift z=0.6174 for the lensing galaxy, and we photometrically estimate z_phot = 2.4\pm0.3 for the arc. We also identify a likely counter-arc at a radius of 0.6 arcsec, which shows structure similar to that seen in the main arc. We model this system and find a good fit to an elliptical isothermal potential of velocity dispersion σ≈300\sigma \approx 300 \kms, the value expected from the fundamental plane, and some external shear. Several other galaxies in the field have colors similar to the lensing galaxy and likely make up a small group.Comment: Accepted for publication in ApJ Letters. 10 pages, 3 figures. Figures have been degraded to meet size limit; a higher resolution version and addtional pictures available at http://acs.pha.jhu.edu/~jpb/UDFparc

    Development of Quality Control Ranges for Biocide Susceptibility Testing

    Get PDF
    Every laboratory test needs validation by quality controls. For biocide susceptibility testing (BST), neither quality control (QC) strains nor QC ranges applicable to these strains are currently available. As QC strains, four well-defined laboratory reference strains (Staphylococcus aureus ATCC¼ 6538, Enterococcus hirae ATCC¼ 10541, Escherichia coli ATCC¼ 10536 and Pseudomonas aeruginosa ATCC¼ 15442), which have been used previously for biocide efficacy testing, were selected. In an interlaboratory trial with eleven participating laboratories, BST QC ranges should be developed for the aforementioned four strains and the four biocides benzalkonium chloride, chlorhexidine, octenidine and polyhexanide. The performance of three different lots of tryptic soy broth was explored using the broth microdilution method and the data were subsequently evaluated using the RangeFinder software. As a result, QC ranges were defined for all reference strain–biocide combinations, except for P. aeruginosa ATCC¼ 15442 with the two biocides chlorhexidine and polyhexanide. The development of the latter two QC ranges was not possible, due to the limited solubility of the biocides in the test range required for P. aeruginosa ATCC¼ 15442. The newly developed QC ranges comprise three to five dilution steps. The establishment of QC ranges will contribute to the validation of BST in the future

    Discovery of Two Distant Type Ia Supernovae in the Hubble Deep Field North with the Advanced Camera for Surveys

    Get PDF
    We present observations of the first two supernovae discovered with the recently installed Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The supernovae were found in Wide Field Camera images of the Hubble Deep Field North taken with the F775W, F850LP, and G800L optical elements as part of the ACS guaranteed time observation program. Spectra extracted from the ACS G800L grism exposures confirm that the objects are Type Ia supernovae (SNe Ia) at redshifts z=0.47 and z=0.95. Follow-up HST observations have been conducted with ACS in F775W and F850LP and with NICMOS in the near-infrared F110W bandpass, yielding a total of 9 flux measurements in the 3 bandpasses over a period of 50 days in the observed frame. We discuss many of the important issues in doing accurate photometry with the ACS. We analyze the multi-band light curves using two different fitting methods to calibrate the supernovae luminosities and place them on the SNe Ia Hubble diagram. The resulting distances are consistent with the redshift-distance relation of the accelerating universe model, although evolving intergalactic grey dust remains as a less likely possibility. The relative ease with which these SNe Ia were found, confirmed, and monitored demonstrates the potential ACS holds for revolutionizing the field of high-redshift SNe Ia, and therefore of testing the accelerating universe cosmology and constraining the "epoch of deceleration".Comment: 11 pages, 8 embedded figures. Accepted for publication in Ap

    FIGS -- Faint Infrared Grism Survey: Description and Data Reduction

    Get PDF
    The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST) WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four deep fields. Two fields are located in the Great Observatories Origins Deep Survey-North (GOODS-N) area and two fields are located in the Great Observatories Origins Deep Survey-South (GOODS-S) area. One of the southern fields selected is the Hubble Ultra Deep Field. Each of these four fields were observed using the WFC3/G102 grism (0.8ÎŒm\mu m-1.15ÎŒm\mu m continuous coverage) with a total exposure time of 40 orbits (~ 100 kilo-seconds) per field. This reaches a 3 sigma continuum depth of ~26 AB magnitudes and probes emission lines to ≈10−17 erg s−1 cm−2\approx 10^{-17}\ erg\ s^{-1} \ cm^{-2}. This paper details the four FIGS fields and the overall observational strategy of the project. A detailed description of the Simulation Based Extraction (SBE) method used to extract and combine over 10000 spectra of over 2000 distinct sources brighter than m_F105W=26.5 mag is provided. High fidelity simulations of the observations is shown to significantly improve the background subtraction process, the spectral contamination estimates, and the final flux calibration. This allows for the combination of multiple spectra to produce a final high quality, deep, 1D-spectra for each object in the survey.Comment: 21 Pages. 17 Figures. To appear in Ap

    Does Stellar Feedback Create HI Holes? An HST/VLA Study of Holmberg II

    Full text link
    We use deep HST/ACS F555W and F814W photometry of resolved stars in the M81 Group dwarf irregular galaxy Ho II to study the hypothesis that the holes identified in the neutral ISM (HI) are created by stellar feedback. From the deep photometry, we construct color-magnitude diagrams (CMDs) and measure the star formation histories (SFHs) for stars contained in HI holes from two independent holes catalogs, as well as select control fields, i.e., similar sized regions that span a range of HI column densities. Converting the recent SFHs into stellar feedback energies, we find that enough energy has been generated to have created all holes. However, the required energy is not always produced over a time scale that is less than the estimated kinematic age of the hole. The combination of the CMDs, recent SFHs, and locations of young stars shows that the stellar populations inside HI holes are not coherent, single-aged, stellar clusters, as previously suggested, but rather multi-age populations distributed across each hole. From a comparison of the modeled and observed integrated magnitudes, and the locations and energetics of stars inside of HI holes, we propose a potential new model: a viable mechanism for creating the observed HI holes in Ho II is stellar feedback from multiple generations of SF spread out over tens or hundreds of Myr, and thus, the concept of an age for an HI hole is intrinsically ambiguous. We further find that \halpha and 24 micron emission, tracers of the most recent star formation, do not correlate well with the positions of the HI holes. However, UV emission, which traces star formation over roughly the last 100 Myr, shows a much better correlation with the locations of the HI holes.Comment: Accepted for Publication in The Astrophysical Journal; 28 Pages, 31 Figures, a version of this paper with full resolution figures is available at http://homepages.spa.umn.edu/~dweisz/ho_ii_weisz.pd
    • 

    corecore