1,408 research outputs found
Economic inequality and the provision of schooling
This paper was presented at the conference "Unequal incomes, unequal outcomes? Economic inequality and measures of well-being" as part of session 3, "Education and crime in urban neighborhoods." The conference was held at the Federal Reserve Bank of New York on May 7, 1999. The authors examine the empirical evidence on the relationship between school finance reform and student outcomes, review the economic literature in the field, and present new evidence of the effects of reform on community and school composition. They argue that if one's goal is to reduce income inequality substantially, one should not look to school finance reform as a particularly effective policy instrument. Even the most optimistic estimates of the impact of school finance reform on the distribution of student performance indicate that these effects are relatively small. Furthermore, the authors note that these small gains may come at a cost - the movement of higher income families into private sector schools, a development that would lead to less diversity within the public schools.Income distribution ; Income ; Education
An analysis of the effect of Chicago school reform on student performance
Education - Middle West - Chicago (Ill.)
Re-analysis of the radio luminosity function of Galactic HII regions
We have re-analyzed continuum and recombination lines radio data available in
the literature in order to derive the luminosity function (LF) of Galactic HII
regions. The study is performed by considering the first and fourth Galactic
quadrants independently. We estimate the completeness level of the sample in
the fourth quadrant at 5 Jy, and the one in the first quadrant at 2 Jy. We show
that the two samples (fourth or first quadrant) include, as well as giant and
super-giant HII regions, a significant number of sub-giant sources. The LF is
obtained, in each Galactic quadrant, with a generalized Schmidt's estimator
using an effective volume derived from the observed spatial distribution of the
considered HII regions. The re-analysis also takes advantage of recently
published ancillary absorption data allowing to solve the distance ambiguity
for several objects. A single power-law fit to the LFs retrieves a slope equal
to -2.23+/-0.07 (fourth quadrant) and to -1.85+/-0.11 (first quadrant). We also
find marginal evidence of a luminosity break at L_knee = 10^23.45 erg s^(-1)
Hz^(-1) for the LF in the fourth quadrant. We convert radio luminosities into
equivalent H_alpha and Lyman continuum luminosities to facilitate comparisons
with extra-galactic studies. We obtain an average total HII regions Lyman
continuum luminosity of 0.89 +/- 0.23 * 10^(53) sec^(-1), corresponding to 30%
of the total ionizing luminosity of the Galaxy.Comment: accepted for publication in Ap
An Analysis of Private School Closings
We add to the small literature on private school supply by exploring exits of K-12 private schools. We find that the closure of private schools is not an infrequent event, and use national survey data from the National Center for Education Statistics to study closures of private schools. We assume that the probability of an exit is a function of excess supply of private schools over the demand, as well as the school's characteristics such as age, size, and religious affiliation. Our empirical results generally support the implications of the model. Working Paper 07-0
Are Debris Disks and Massive Planets Correlated?
Using data from the Spitzer Space Telescope Legacy Science Program
``Formation and Evolution of Planetary Systems'' (FEPS), we have searched for
debris disks around 9 FGK stars (2-10 Gyr), known from radial velocity (RV)
studies to have one or more massive planets. Only one of the sources, HD 38529,
has excess emission above the stellar photosphere; at 70 micron the
signal-to-noise ratio in the excess is 4.7 while at wavelengths < 30 micron
there is no evidence of excess. The remaining sources show no excesses at any
Spitzer wavelengths. Applying survival tests to the FEPS sample and the results
for the FGK survey published in Bryden et al. (2006), we do not find a
significant correlation between the frequency and properties of debris disks
and the presence of close-in planets. We discuss possible reasons for the lack
of a correlation.Comment: 24 pages, 3 figures. Accepted to Astrophysical Journa
Chemical telemetry of OH observed to measure interstellar magnetic fields
We present models for the chemistry in gas moving towards the ionization
front of an HII region. When it is far from the ionization front, the gas is
highly depleted of elements more massive than helium. However, as it approaches
the ionization front, ices are destroyed and species formed on the grain
surfaces are injected into the gas phase. Photodissociation removes gas phase
molecular species as the gas flows towards the ionization front. We identify
models for which the OH column densities are comparable to those measured in
observations undertaken to study the magnetic fields in star forming regions
and give results for the column densities of other species that should be
abundant if the observed OH arises through a combination of the liberation of
H2O from surfaces and photodissociation. They include CH3OH, H2CO, and H2S.
Observations of these other species may help establish the nature of the OH
spatial distribution in the clouds, which is important for the interpretation
of the magnetic field results.Comment: 11 pages, 2 figures, accepted by Astrophysics and Space Scienc
Kepler Observations of V447 Lyr: An Eclipsing U Gem Cataclysmic Variable
We present the results of an analysis of data covering 1.5 years of the dwarf
nova V447 Lyr. We detect eclipses of the accretion disk by the mass donating
secondary star every 3.74 hrs which is the binary orbital period. V447 Lyr is
therefore the first dwarf nova in the Kepler field to show eclipses. We also
detect five long outbursts and six short outbursts showing V447 Lyr is a U Gem
type dwarf nova. We show that the orbital phase of the mid-eclipse occurs
earlier during outbursts compared to quiescence and that the width of the
eclipse is greater during outburst. This suggests that the bright spot is more
prominent during quiescence and that the disk is larger during outburst than
quiescence. This is consistent with an expansion of the outer disk radius due
to the presence of high viscosity material associated with the outburst,
followed by a contraction in quiescence due to the accretion of low angular
momentum material. We note that the long outbursts appear to be triggered by a
short outburst, which is also observed in the super-outbursts of SU UMa dwarf
novae as observed using Kepler.Comment: Accepted by MNRA
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