849 research outputs found

    Attitudes Toward Anger Management Scale: Development and Initial Validation

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    This article describes the development and preliminary validation of the Attitudes Toward Anger Management Scale (ATAMS), a self-report measure of attitudes toward anger management services. Undergraduate volunteers (N = 415) completed an initial version of the instrument. Principal components analysis yielded a two-factor solution. Convergent and incremental validities were supported

    The Evolution of the Optical and Near-Infrared Galaxy Luminosity Functions and Luminosity Densities to z~2

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    Using Hubble Space Telescope and ground-based U through K- band photometry from the Great Observatories Origins Deep Survey (GOODS), we measure the evolution of the luminosity function and luminosity density in the rest-frame optical (UBR) to z ~ 2, bridging the poorly explored ``redshift desert'' between z~1 and z~2. We also use deep near-infrared observations to measure the evolution in the rest-frame J-band to z~1. Compared to local measurements from the SDSS, we find a brightening of the characteristic magnitude, (M*), by ~2.1, \~0.8 and ~0.7 mag between z=0.1 and z=1.9, in U, B, and R bands, respectively. The evolution of M* in the J-band is in the opposite sense, showing a dimming between redshifts z=0.4 and z=0.9. This is consistent with a scenario in which the mean star formation rate in galaxies was higher in the past, while the mean stellar mass was lower, in qualitative agreement with hierarchical galaxy formation models. We find that the shape of the luminosity function is strongly dependent on spectral type and that there is strong evolution with redshift in the relative contribution from the different spectral types to the luminosity density. We find good agreement in the luminosity function derived from an R-selected and a K-selected sample at z~1, suggesting that optically selected surveys of similar depth (R < 24) are not missing a significant fraction of objects at this redshift relative to a near-infrared-selected sample. We compare the rest-frame B-band luminosity functions from z~0--2 with the predictions of a semi-analytic hierarchical model of galaxy formation, and find qualitatively good agreement. In particular, the model predicts at least as many optically luminous galaxies at z~1--2 as are implied by our observations.Comment: 43 pages; 15 Figures; 5 Tables, Accepted for publication in Ap.

    On the Relation Between Peak Luminosity and Parent Population of Type Ia Supernovae: A New Tool for Probing the Ages of Distant Galaxies

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    We study the properties of Type Ia Supernovae (SNe Ia) as functions of the radial distance from their host galaxy centers. Using a sample of 62 SNe Ia with reliable luminosity, reddening, and decline rate determinations, we find no significant radial gradients of SNe Ia peak absolute magnitudes or decline rates in elliptical+S0 galaxies, suggesting that the diversity of SN properties is not related to the metallicity of their progenitors. We do find that the range in brightness and light curve width of supernovae in spiral galaxies extends to brighter, broader values. These results are interpreted as support for an age, but not metallicity, related origin of the diversity in SNe Ia. If confirmed with a larger and more accurate sample of data, the age-luminosity relation would offer a new and powerful tool to probe the ages and age gradients of stellar populations in galaxies at redshift as high as z12z\sim1-2. The absence of significant radial gradients in the peak (BV)0\rm (B-V)_0 and (VI)0\rm (V-I)_0 colors of SNe Ia supports the redding correction method of Phillips et al (1999). We find no radial gradient in residuals from the SN Ia luminosity-width relation, suggesting that the relation is not affected by properties of the progenitor populations and supporting the reliability of cosmological results based upon the use of SNe Ia as distance indicators.Comment: 19 pages, incl. 3 tables & 3 figures; to appear in Nov 2000 issue of Ap

    Leukotrienes in the rat central nervous system.

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    Relation Between Stellar Mass and Star Formation Activity in Galaxies

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    For a mass-selected sample of 66544 galaxies with photometric redshifts from the Cosmic Evolution Survey (COSMOS), we examine the evolution of star formation activity as a function of stellar mass in galaxies. We estimate the cosmic star formation rates (SFR) over the range 0.2 < z < 1.2, using the rest-frame 2800 A flux (corrected for extinction). We find the mean SFR to be a strong function of the galactic stellar mass at any given redshift, with massive systems (log (M/M(Sun)) > 10.5) contributing less (by a factor of ~ 5) to the total star formation rate density (SFRD). Combining data from the COSMOS and Gemini Deep Deep Survey (GDDS), we extend the SFRD-z relation as a function of stellar mass to z~2. For massive galaxies, we find a steep increase in the SFRD-z relation to z~2; for the less massive systems, the SFRD which also increases from z=0 to 1, levels off at z~1. This implies that the massive systems have had their major star formation activity at earlier epochs (z > 2) than the lower mass galaxies. We study changes in the SFRDs as a function of both redshift and stellar mass for galaxies of different spectral types. We find that the slope of the SFRD-z relation for different spectral type of galaxies is a strong function of their stellar mass. For low and intermediate mass systems, the main contribution to the cosmic SFRD comes from the star-forming galaxies while, for more massive systems, the evolved galaxies are the most dominant population.Comment: 34 pages; 8 figures; Accepted for publication in Ap

    The Age-Redshift Relation for Standard Cosmology

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    We present compact, analytic expressions for the age-redshift relation τ(z)\tau(z) for standard Friedmann-Lema\^ \itre-Robertson-Walker (FLRW) cosmology. The new expressions are given in terms of incomplete Legendre elliptic integrals and evaluate much faster than by direct numerical integration.Comment: 13 pages, 3 figure

    Warm perineal compresses during the second stage of labor for reducing perineal trauma: A meta-analysis

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    OBJECTIVE: Perineal trauma may have a negative impact on women's lives as it has been associated with perineal pain, urinary incontinence and sexual dysfunction. The aim of this systematic review and meta-analysis of randomized controlled trials was to evaluate the effectiveness of warm compresses during the second stage of labor in reducing perineal trauma. METHODS: Electronic databases were searched from inception of each database to May 2019. Inclusion criteria were randomized trials comparing warm compresses (i.e. intervention group) with no warm compresses (i.e. control group) during the second stage of labor. Types of participants included pregnant women planning to have a spontaneous vaginal birth at term with a singleton in a cephalic presentation. The primary outcome was the incidence of intact perineum. Meta-analysis was performed using the Cochrane Collaboration methodology with results being reported as relative risk (RR) with 95% confidence interval (CI). RESULTS: Seven trials, including 2103 participants, were included in this meta-analysis. Women assigned to the intervention group received warm compresses made from clean washcloths or perineal pads immersed in warm tap water. These were held against the woman's perineum during and in between pushes in second stage. Warm compresses usually started when the baby's head began to distend the perineum or when there was active fetal descent in the second stage of labor. We found a higher rate of intact perineum in the intervention group compared to the control group (22.4% vs 15.4%; RR 1.46, 95% CI 1.22 to 1.74); a lower rate of third degree tears (1.9% vs 5.0%; RR 0.38, 95% CI 0.22 to 0.64), fourth degree tears (0.0% vs 0.9%; RR 0.11, 95% CI 0.01 to 0.86) third and fourth degree tears combined (1.9% vs 5.8%; RR 0.34, 95% CI 0.20 to 0.56) and episiotomy (10.4% vs 17.1%; RR 0.61, 95% CI 0.51 to 0.74). CONCLUSION: Warm compresses applied during the second stage of labor increase the incidence of intact perineum and lower the risk of episiotomy and severe perineal trauma

    Designing Future Dark Energy Space Missions: II. Photometric Redshift of Space Weak Lensing Optimized Survey

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    Accurate weak-lensing analysis requires not only accurate measurement of galaxy shapes but also precise and unbiased measurement of galaxy redshifts. The photometric redshift technique appears as the only possibility to determine the redshift of the background galaxies used in the weak-lensing analysis. Using the photometric redshift quality, simple shape measurement requirements, and a proper sky model, we explore what could be an optimal weak-lensing dark energy mission based on FoM calculation. We found that photometric redshifts reach their best accuracy for the bulk of the faint galaxy population when filters have a resolution R~3.2. We show that an optimal mission would survey the sky through 8 filters using 2 cameras (visible and near infrared). Assuming a 5-year mission duration, a mirror size of 1.5m, a 0.5deg2 FOV with a visible pixel scale of 0.15", we found that a homogeneous survey reaching IAB=25.6 (10sigma) with a sky coverage of ~11000deg2 maximizes the Weak Lensing FoM. The effective number density of galaxies then used for WL is ~45gal/arcmin2, at least a factor of two better than ground based survey. This work demonstrates that a full account of the observational strategy is required to properly optimize the instrument parameters to maximize the FoM of the future weak-lensing space dark energy mission.Comment: 25 pages, 39 figures, accepted in A&

    Photometric Redshifts of Galaxies in COSMOS

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    We measure photometric redshifts and spectral types for galaxies in the COSMOS survey. We use template fitting technique combined with luminosity function priors and with the option to simultaneously estimate dust extinction (i.e. E(B-V)) for each galaxy.Our estimated redshifts are accurate to i<25 and z~1.2. Using simulations with sampling and noise characteristics similar to those in COSMOS, the accuracy and reliability is estimated for the photometric redshifts as a function of the magnitude limits of the sample, S/N ratios and the number of bands used. From the simulations we find that the ratio of derived 95% confidence interval in the redshift probability distribution to the estimated photometric redshift (D95) can be used to identify and exclude the catastrophic failures in the photometric redshift estimates. We compare the derived redshifts with high-reliability spectroscopic redshifts for a sample of 868 normal galaxies with z < 1.2 from zCOSMOS. Considering different scenarios, depending on using prior, no prior and/or extinction, we compare the photometric and spectroscopic redshifts for this sample. This corresponds to an rms scatter of 0.031, with a small number of outliers (<2.5%). We also find good agreement (rms=0.10) between photometric and spectroscopic redshifts for Type II AGNs. We compare results from our photometric redshift procedure with three other independent codes and find them in excellent agreement. We show preliminary results, based on photometric redshifts for the entire COSMOS sample (to i < 25 mag.).Comment: 38 pages; 14 Figures; 7 Tables. Accepted for Publication in ApJS. COSMOS Special Issu
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