3,593 research outputs found
The HI Mass Function and Velocity Width Function of Void Galaxies in the Arecibo Legacy Fast ALFA Survey
We measure the HI mass function (HIMF) and velocity width function (WF)
across environments over a range of masses ,
and profile widths , using a catalog of
~7,300 HI-selected galaxies from the ALFALFA Survey, located in the region of
sky where ALFALFA and SDSS (Data Release 7) North overlap. We divide our galaxy
sample into those that reside in large-scale voids (void galaxies) and those
that live in denser regions (wall galaxies). We find the void HIMF to be well
fit by a Schechter function with normalization
, characteristic mass
, and low-mass-end slope
. Similarly, for wall galaxies, we find best-fitting
parameters ,
, and . We
conclude that void galaxies typically have slightly lower HI masses than their
non-void counterparts, which is in agreement with the dark matter halo mass
function shift in voids assuming a simple relationship between DM mass and HI
mass. We also find that the low-mass slope of the void HIMF is similar to that
of the wall HIMF suggesting that there is either no excess of low-mass galaxies
in voids or there is an abundance of intermediate HI mass galaxies. We fit a
modified Schechter function to the ALFALFA void WF and determine its
best-fitting parameters to be ,
, and high-width slope
. For wall galaxies, the WF parameters are:
, ,
and . Because of large uncertainties on
the void and wall width functions, we cannot conclude whether the WF is
dependent on the environment.Comment: Accepted for publication at MNRAS, 14 pages, 12 figure
A Contextual Approach to Social Skills Assessment in the Peer Group: Who Is the Best Judge?
Using a contextual approach to social skills assessment in the peer group, this study examined the criterion- related validity of contextually relevant social skills and the incremental validity of peers and teachers as judges of children’s social skills. Study participants included 342 (180 male and 162 female) students and their classroom teachers (N = 22) from rural communities. As expected, contextually relevant social skills were significantly related to a variety of social status indicators (i.e., likability, peer- and teacher-assessed popularity, reciprocated friendships, clique centrality) and positive school functioning (i.e., school liking and academic competence). Peer-assessed social skills, not teacher-assessed social skills, demonstrated consistent incremental validity in predicting various indicators of social status outcomes; peer- and teacher-assessed social skills alike showed incremental validity in predicting positive school functioning. The relation between contextually relevant social skills and study outcomes did not vary by child gender. Findings are discussed in terms of the significance of peers in the assessment of children’s social skills in the peer group as well as the usefulness of a contextual approach to social skills assessment
A Contextual Approach to Social Skills Assessment in the Peer Group: Who Is the Best Judge?
Using a contextual approach to social skills assessment in the peer group, this study examined the criterion- related validity of contextually relevant social skills and the incremental validity of peers and teachers as judges of children’s social skills. Study participants included 342 (180 male and 162 female) students and their classroom teachers (N = 22) from rural communities. As expected, contextually relevant social skills were significantly related to a variety of social status indicators (i.e., likability, peer- and teacher-assessed popularity, reciprocated friendships, clique centrality) and positive school functioning (i.e., school liking and academic competence). Peer-assessed social skills, not teacher-assessed social skills, demonstrated consistent incremental validity in predicting various indicators of social status outcomes; peer- and teacher-assessed social skills alike showed incremental validity in predicting positive school functioning. The relation between contextually relevant social skills and study outcomes did not vary by child gender. Findings are discussed in terms of the significance of peers in the assessment of children’s social skills in the peer group as well as the usefulness of a contextual approach to social skills assessment
Theme Overview: Agriculture and Water Quality in the Cornbelt: Overview of Issues and Approaches
Resource /Energy Economics and Policy, Q25,
- …