279 research outputs found

    Representativeness of observed couple interactions: Couples can tell, and it does make a difference

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    Research evidence suggests that people's public self-presentations may be biased in socially desirable directions. Using videotaped samples of couple interactions, this study examined the extent to which self-presentational bias occurs in such samples and the impact of such bias on the predictive validity of observed behavior. Each member of 239 couples rated the typicality of their partner's taped socially supportive and undermining behaviors. Separate multi-item, internally consistent measures of typicality of support and undermining were found. Analyses showed that these measures did not appear subject to bias and could identify subgroups that varied notably in the criterion validity of their observational data. These effects appeared for typicality of social support but not for typicality of social undermining. Partner ratings may be a promising tool for isolating invalid samples of observed behavior. One of the most challenging tasks in psychological research is the collection of valid observational data on people in normal social interactions. Such observations are usually interpreted as reflections of more general patterns of behavior because they occur in natural settings, and they are considered valid if they are such reflections. Scientists who conduct observational research, however, have long been aware that various characteristics of the research design can affect participants' behavior during such data collection. For example, Gottman (1979, p. 248) has found evidence that couples' behavior is more negative, with more negative affect reciprocity and less agreement, when assessed in the home rather than in a laboratory setting. A large body of evidence suggests that such effects may occur because people tend to bias their self-presentations of private behavior in socially desirable directions during public interac

    From field experiments to program implementation: Assessing the potential outcomes of an experimental intervention program for unemployed persons

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44031/1/10464_2004_Article_BF00937991.pd

    The effects of dust in simple environments: Large Magellanic Cloud HII regions

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    We investigate the effects of dust on Large Magellanic Cloud (LMC) HII region spectral energy distributions using arcminute-resolution far-ultraviolet (FUV), H-alpha, far-infrared (FIR), and radio images. Widely-used indicators of the amount of light lost to dust (attenuation) at H-alpha and in the FUV correlate with each other, although often with substantial scatter. There are two interesting systematic discrepancies. First, H-alpha attenuations estimated from the Balmer decrement are lower than those estimated from the H-alpha-to-thermal radio luminosity ratio. Our data, at this stage, cannot unambiguously identify the source of this discrepancy. Second, the attenuation at 1500 angstroms and UV spectral slope, beta, correlate, although the slope and scatter are substantially different from the correlation first derived for starbursting galaxies by Calzetti et al. Combining our result with those of Meurer et al. for ultra-luminous infrared galaxies and Calzetti et al. for starbursting galaxies, we conclude that no single relation between beta and 1500 angstrom attenuation is applicable to all star-forming systems.Comment: 15 pages; 11 embedded postscript figures; 1 GIF figure; to appear in ApJ on 20 January 2002, vol. 565, no. 1. Section 5.1 (the discussion of the discrepancies between Balmer-derived and Radio-derived H alpha attenuations) has changed considerably to take into account small number statistics for high-mass stars in the model HII region IMFs. The abstract and conclusions have been modifie

    Star Formation in Galaxies Along the Hubble Sequence

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    Observations of star formation rates (SFRs) in galaxies provide vital clues to the physical nature of the Hubble sequence, and are key probes of the evolutionary properties of galaxies. The focus of this review is on the broad patterns in the star formation properties of galaxies along the Hubble sequence, and their implications for understanding galaxy evolution and the physical processes that drive the evolution. Star formation in the disks and nuclear regions of galaxies are reviewed separately, then discussed within a common interpretive framework. The diagnostic methods used to measure SFRs are also reviewed, and a self-consistent set of SFR calibrations is presented as an aid to workers in the field.Comment: 41 pages, with 9 figures. To appear in Volume 36 of the Annual Review of Astronomy and Astrophysic

    A Plan for a Long-Term, Automated, Broadband Seismic Monitoring Network on the Global Seafloor

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    Establishing an extensive and highly durable, long‐term, seafloor network of autonomous broadband seismic stations to complement the land‐based Global Seismographic Network has been a goal of seismologists for decades. Seismic signals, chiefly the vibrations from earthquakes but also signals generated by storms and other environmental processes, have been processed from land‐based seismic stations to build intriguing but incomplete images of the Earth’s interior. Seismologists have mapped structures such as tectonic plates and other crustal remnants sinking deep into the mantle to obtain information on their chemical composition and physical state; but resolution of these structures from land stations is not globally uniform. Because the global surface is two‐thirds ocean, increasing the number of seismic stations located in the oceans is critical for better resolution of the Earth’s interior and tectonic structures. A recommendation for a long‐term seafloor seismic station pilot experiment is presented here. The overarching instrumentation goal of a pilot experiment is performance that will lead to the installation of a large number of long‐term autonomous ocean‐bottom seismic stations. The payoff of a network of stations separated from one another by a few hundred kilometers under the global oceans would be greatly refined resolution of the Earth’s interior at all depths. A second prime result would be enriched understanding of large‐earthquake rupture processes in both oceanic and continental plates. The experiment would take advantage of newly available technologies such as robotic wave gliders that put an affordable autonomous prototype within reach. These technologies would allow data to be relayed to satellites from seismometers that are deployed on the seafloor with long‐lasting, rechargeable batteries. Two regions are presented as promising arenas for such a prototype seafloor seismic station. One site is the central North Atlantic Ocean, and the other high‐interest locale is the central South Pacific Ocean

    The Nature of Infrared Emission in the Local Group Dwarf Galaxy NGC 6822 As Revealed by Spitzer

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    We present Spitzer imaging of the metal-deficient (Z ~30% Z_sun) Local Group dwarf galaxy NGC 6822. On spatial scales of ~130 pc, we study the nature of IR, H alpha, HI, and radio continuum emission. Nebular emission strength correlates with IR surface brightness; however, roughly half of the IR emission is associated with diffuse regions not luminous at H alpha (as found in previous studies). The global ratio of dust to HI gas in the ISM, while uncertain at the factor of ~2 level, is ~25 times lower than the global values derived for spiral galaxies using similar modeling techniques; localized ratios of dust to HI gas are about a factor of five higher than the global value in NGC 6822. There are strong variations (factors of ~10) in the relative ratios of H alpha and IR flux throughout the central disk; the low dust content of NGC 6822 is likely responsible for the different H alpha/IR ratios compared to those found in more metal-rich environments. The H alpha and IR emission is associated with high-column density (> ~1E21 cm^-2) neutral gas. Increases in IR surface brightness appear to be affected by both increased radiation field strength and increased local gas density. Individual regions and the galaxy as a whole fall within the observed scatter of recent high-resolution studies of the radio-far IR correlation in nearby spiral galaxies; this is likely the result of depleted radio and far-IR emission strengths in the ISM of this dwarf galaxy.Comment: ApJ, in press; please retrieve full-resolution version from http://www.astro.wesleyan.edu/~cannon/pubs.htm

    The Incidence of Highly-Obscured Star-Forming Regions in SINGS Galaxies

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    Using the new capabilities of the Spitzer Space Telescope and extensive multiwavelength data from the Spitzer Infrared Nearby Galaxies Survey (SINGS), it is now possible to study the infrared properties of star formation in nearby galaxies down to scales equivalent to large HII regions. We are therefore able to determine what fraction of large, infrared-selected star-forming regions in normal galaxies are highly obscured and address how much of the star formation we miss by relying solely on the optical portion of the spectrum. Employing a new empirical method for deriving attenuations of infrared-selected star-forming regions we investigate the statistics of obscured star formation on 500pc scales in a sample of 38 nearby galaxies. We find that the median attenuation is 1.4 magnitudes in H-alpha and that there is no evidence for a substantial sub-population of uniformly highly-obscured star-forming regions. The regions in the highly-obscured tail of the attenuation distribution (A_H-alpha > 3) make up only ~4% of the sample of nearly 1800 regions, though very embedded infrared sources on the much smaller scales and lower luminosities of compact and ultracompact HII regions are almost certainly present in greater numbers. The highly-obscured cases in our sample are generally the bright, central regions of galaxies with high overall attenuation but are not otherwise remarkable. We also find that a majority of the galaxies show decreasing radial trends in H-alpha attenuation. The small fraction of highly-obscured regions seen in this sample of normal, star-forming galaxies suggests that on 500pc scales the timescale for significant dispersal or break up of nearby, optically-thick dust clouds is short relative to the lifetime of a typical star-forming region.Comment: Accepted for publication in ApJ; emulateapj style, 30 pages, 18 figures (compressed versions), 3 table
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