10,693 research outputs found
Behavioral Economics and Developmental Science: A New Framework to Support Early Childhood Interventions
Public policies have actively responded to an emergent social and neuroscientific evidence base documenting the benefits of targeting services to children during the earliest period of their development. But problems of low utilization, inconsistent participation, and low retention continue to present themselves as challenges. Although most interventions recognize and address structural and psycho-social barriers to parent’s engagement, few take seriously the decision making roles of parents. Using insights from the behavioral sciences, we revisit assumptions about the presumed behavior of parents in a developmental context. We then describe ways in which this framework informs features of interventions that can be designed to augment the intended impacts of early development, education and care initiatives by improving parent engagement
Structure of large random hypergraphs
The theme of this paper is the derivation of analytic formulae for certain
large combinatorial structures. The formulae are obtained via fluid limits of
pure jump type Markov processes, established under simple conditions on the
Laplace transforms of their Levy kernels. Furthermore, a related Gaussian
approximation allows us to describe the randomness which may persist in the
limit when certain parameters take critical values. Our method is quite
general, but is applied here to vertex identifiability in random hypergraphs. A
vertex v is identifiable in n steps if there is a hyperedge containing v all of
whose other vertices are identifiable in fewer than n steps. We say that a
hyperedge is identifiable if every one of its vertices is identifiable. Our
analytic formulae describe the asymptotics of the number of identifiable
vertices and the number of identifiable hyperedges for a Poisson random
hypergraph on a set of N vertices, in the limit as N goes to infinity.Comment: Revised version with minor conceptual improvements and additional
discussion. 32 pages, 5 figure
"Invisible AGN" I: Sample Selection and Optical/Near-IR Spectral Energy Distributions
In order to find more examples of the elusive high-redshift molecular
absorbers, we have embarked on a systematic discovery program for highly
obscured, radio-loud "invisible AGN" using the VLA Faint Images of the Radio
Sky at Twenty centimeters (FIRST) radio survey in conjunction with Sloan
Digital Sky Survey (SDSS) to identify 82 strong (> 300 mJy) radio sources
positionally coincident with late-type, presumably gas-rich galaxies. In this
first paper, the basic properties of this sample are described including the
selection process and the analysis of the spectral-energydistributions (SEDs)
derived from the optical (SDSS) + near-IR (NIR) photometry obtained by us at
the Apache Point Observatory 3.5m. The NIR images confirm the late-type galaxy
morphologies found by SDSS for these sources in all but a few (6 of 70) cases
(12 previously well-studied or misclassified sources were culled). Among 70
sources in the final sample, 33 show galaxy type SEDs, 17 have galaxy
components to their SEDs, and 20 have quasar power-law continua. At least 9
sources with galaxy SEDs have K-band flux densities too faint to be giant
ellipticals if placed at their photometric redshifts. Photometric redshifts for
this sample are analyzed and found to be too inaccurate for an efficient
radio-frequency absorption line search; spectroscopic redshifts are required. A
few new spectroscopic redshifts for these sources are presented here but more
will be needed to make significant progress in this field. Subsequent papers
will describe the radio continuum properties of the sample and the search for
redshifted H I 21 cm absorption.Comment: 32 pages, 9 figures, accepted by A
A Radio Spectral Line Study of the 2-Jy IRAS-NVSS Sample: Part I
We present results from an on-going survey for the HI 21 cm line and the OH
18 cm lines in IR galaxies with the Arecibo 305 m Radio Telescope. The
observations of 85 galaxies extracted from the 2 Jy IRAS-NVSS sample in the
R.A. (B1950) range 20 h-00 h are reported in this paper. We detected the HI 21
cm line in 82 of these galaxies, with 18 being new detections, and the OH 18 cm
lines in 7 galaxies, with 4 being new detections. In some cases, the HI spectra
show the classic double-horned or single-peaked emission profiles. However, the
majority exhibit distorted HI spectral features indicating that the galaxies
are in interacting and/or merging systems. From these HI and OH observations,
various properties of the sample are derived and reported.Comment: 38 pages, 7 figures, 9 tables. Accepted for publication in A
On the X-ray Properties of OH Megamaser Sources: Chandra Snapshot Observations
We present Chandra snapshot observations for a sample of 7 sources selected
from the Arecibo OH megamaser (OHM) survey at z~0.13-0.22 and with far-infrared
luminosities in excess of 10^{11} L_sun. In contrast with the known H2O
megamasers, which are mostly associated with powerful Active Galactic Nuclei
(AGN), the situation is far less clear for OHMs, which have been poorly studied
in the X-ray band thus far. All of the observed sources are X-ray weak, with
only one OHM, IRAS FSC 03521+0028 (z=0.15), being detected by Chandra (with 5
counts). The results from this pilot program indicate that the X-ray emission,
with luminosities of less than ~10^{42} erg/s, is consistent with that from
star formation (as also suggested in some cases by the optical spectra) and
low-luminosity AGN emission. If an AGN is present, its contribution to the
broad-band emission of OHM galaxies is likely modest. Under reasonable
assumptions about the intrinsic X-ray spectral shape, the observed count
distribution from stacking analysis suggests absorption of ~10^{22} cm^{-2}.Comment: 8 pages, 3 figures, accepted for publication in MNRA
Fortran 4 program for two-impulse rendezvous analysis
Program determines if rendezvous in near space is possible, and performs an analysis to determine the approximate required values of the magnitude and direction of two thrust applications of the upper stage of a rocket firing. The analysis is performed by using ordinary Keplerian mechanics
The Economic Impacts of the Regional Greenhouse Gas Initiative on Ten Northeast and Mid-Atlantic States
Assesses outcomes of the first U.S. market-based program to reduce emissions of carbon dioxide from power plants, including impact on electricity markets, power companies' costs, and consumer prices; use of auction proceeds; and states' economic benefits
Recommended from our members
Injectable and Spatially Patterned Microporous Annealed Particle (MAP) Hydrogels for Tissue Repair Applications.
Spatially patterned hydrogels are becoming increasingly popular in the field of regenerative medicine and tissue repair because of their ability to guide cell infiltration and migration. However, postfabrication technologies are usually required to spatially pattern a hydrogel, making these hydrogels difficult to translate into the clinic. Here, an injectable spatially patterned hydrogel is reported using hyaluronic acid (HA)-based particle hydrogels. These particle hydrogels are sequentially loaded into a syringe to form a pattern and, once injected, they maintain the pattern. The applicability of this hydrogel in a wound healing skin model, a subcutaneous implant model, as well as a stroke brain model is examined and distinct patterning in all models tested is shown. This injectable and spatially patterned hydrogel can be used to create physical or biochemical gradients. Further, this design can better match the scaffold properties within the physical location of the tissue (e.g., wound border vs wound center). This allows for better design features within the material that promote repair and regeneration
- …
