279 research outputs found
Representativeness of observed couple interactions: Couples can tell, and it does make a difference
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
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
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
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
Establishing an extensive and highly durable, longâterm, seafloor network of autonomous broadband seismic stations to complement the landâbased 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 landâbased seismic stations to build intriguing but incomplete images of the Earthâs 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 twoâthirds ocean, increasing the number of seismic stations located in the oceans is critical for better resolution of the Earthâs interior and tectonic structures. A recommendation for a longâterm 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 longâterm autonomous oceanâbottom 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 Earthâs interior at all depths. A second prime result would be enriched understanding of largeâearthquake 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 longâlasting, 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 highâinterest locale is the central South Pacific Ocean
The Nature of Infrared Emission in the Local Group Dwarf Galaxy NGC 6822 As Revealed by Spitzer
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
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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