2,925 research outputs found
Legal Rules and Bankruptcy Rates: Historical Evidence from the States
Since the early twentieth century, observers have attributed the wide variation in state bankruptcy rates to variation in state legal rules such as garnishment and bankruptcy exemptions. Recent econometric analyses, however, conclude that legal rules do not matter. We explore the impact of legal rules on bankruptcy rates using a new techniqueâfixed effects vector decompositionâto exploit historical variation in legal rules. The technique allows us to estimate the impact of timeinvariant legal rules in a fixed effects framework. We find that the variation in state legal rules explains much of the variation in state wage earner bankruptcy rates for 1926 to 1932.Bankruptcy, fixed effects vector decomposition, law and economics
New Evidence on Race Discrimination Under Separate But Equal
Recently uncovered data on teachersâ salaries in Virginia in 1906 allow for more precise and consistent estimations of marginal returns to certification and formal education than had been available in previous studies. Virginia\u27s âseparate but equalâ educational system paid black teachers in rural counties lower wages than it paid white teachers and on average paid a lower premium to blacks for certification and formal education than it paid to whites. In incorporated cities, returns to certification and normal school education were about the same for black teachers and white teachers, although average salaries were lower for black teachers
The Evolution of Garnishment and Wage Assignment Law in Illinois
Recent research shows that, despite high interest rates, wage earners in the early twentieth century frequently obtained credit from retail shops, from loan sharks, and from the emerging formal consumer credit market. When wage earners defaulted, the options for collection available to their creditors were governed by state laws on garnishment and wage assignment. These important laws varied widely from state to state, and little is known about their origins or evolution. In Illinois, the law put significant restrictions on creditors in the late nineteenth century, but the restrictions were removed in the first quarter of the twentieth century. This article shows how this dramatic shift resulted from the interaction of legislative and judicial activity and was driven by both interest group politics and judicial action
Merger of Black Holes in the Galactic Center
We present the results of three body simulations focused on understanding the
fates of intermediate mass black holes (IBH) that drift within the central 0.5
pc of the Galaxy. In particular, we modeled the interactions between pairs of
black holes as they orbit a central blac k hole of mass
. The simulations performed assume a
Schwarzschild geometry and account for Chandrasekhar dynamical friction as well
as acceleration resulting from energy lost due to gravitational radiation.
We found the branching ratio for one of the orbiting IBHs to merge with the
CBH was 0.95 and is independent of the inner IBH's initial eccentricity as well
as the rate of sinking. This, coupled with an infall rate of yrs
for an IBH to drift into the Galactic center, results in an IBH-CBH merger
every Myrs. Lastly we found that the IBH-IBH-CBH triple body
system ``resets'' itself, in the sense that a system with an inner I BH with an
initially circular orbit generally left behind an IBH with a large
eccentricity, whereas a system in which the inner IBH had a high eccentricity
() usually left a remnant with low eccentricity. Branching ratios
for different outcomes are also similar in the two cases.Comment: Official paper to appear in November 2008 issue of Ap
On Signatures of Atmospheric Features in Thermal Phase Curves of Hot Jupiters
Turbulence is ubiquitous in Solar System planetary atmospheres. In hot
Jupiter atmospheres, the combination of moderately slow rotation and thick
pressure scale height may result in dynamical weather structures with unusually
large, planetary-size scales. Using equivalent-barotropic, turbulent
circulation models, we illustrate how such structures can generate a variety of
features in the thermal phase curves of hot Jupiters, including phase shifts
and deviations from periodicity. Such features may have been spotted in the
recent infrared phase curve of HD 189733b. Despite inherent difficulties with
the interpretation of disk-integrated quantities, phase curves promise to offer
unique constraints on the nature of the circulation regime present on hot
Jupiters.Comment: 22 pages, 6 figures, 1 table, accepted for publication in Ap
Toward Eclipse Mapping of Hot Jupiters
Recent Spitzer infrared measurements of hot Jupiter eclipses suggest that
eclipse mapping techniques could be used to spatially resolve the day-side
photospheric emission of these planets using partial occultations. As a first
step in this direction, we simulate ingress/egress lightcurves for the three
brightest known eclipsing hot Jupiters and evaluate the degree to which
parameterized photospheric emission models can be distinguished from each other
with repeated, noisy eclipse measurements. We find that the photometric
accuracy of Spitzer is insufficient to use this tool effectively. On the other
hand, the level of photospheric details that could be probed with a few JWST
eclipse measurements could greatly inform hot Jupiter atmospheric modeling
efforts. A JWST program focused on non-parametric eclipse map inversions for
hot Jupiters should be actively considered.Comment: 32 pages, 6 figures, 3 tables, accepted for publication in Ap
Early Evidence for Using a Train-the-Trainer Program to Teach Debriefing for Meaningful Learning
Background Competent debriefers are essential to promote positive learner outcomes. While important, providing training to faculty may be difficult. The Train-The-Trainer (TTT) model is a successful approach for efficiently training large groups of individuals. Methods This study used a purposive, descriptive research design to test the feasibility and effectiveness of a TTT program for teaching debriefers how to implement and train others to use Debriefing for Meaningful Learning (DML). Results With training, assessment, and individualized feedback, trainers and trainees alike improved their ability to use DML, as well as self-assess their debriefing. Conclusion The TTT program was a successful, feasible, cost-effective way to provide DML training
Pigment signatures of algal communities and their implications for glacier surface darkening
Blooms of pigmented algae darken the surface of glaciers and ice sheets, thereby enhancing solar energy absorption and amplifying ice and snow melt. The impacts of algal pigment and community composition on surface darkening are still poorly understood. Here, we characterise glacier ice and snow algal pigment signatures on snow and bare ice surfaces and study their role in photophysiology and energy absorption on three glaciers in Southeast Greenland. Purpurogallin and astaxanthin esters dominated the glacier ice and snow algal pigment pools (mass ratios to chlorophyll a of 32 and 56, respectively). Algal biomass and pigments impacted chromophoric dissolved organic matter concentrations. Despite the effective absorption of astaxanthin esters at wavelengths where incoming irradiance peaks, the cellular energy absorption of snow algae was 95% lower than anticipated from their pigmentation, due to pigment packaging. The energy absorption of glacier ice algae was consequentlyâ~â5âĂâhigher. On bare ice, snow algae may have locally contributed up to 13% to total biological radiative forcing, despite contributing 44% to total biomass. Our results give new insights into the impact of algal community composition on bare ice energy absorption and biomass accumulation during snow melt
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