469 research outputs found
Wirtschaftswunder: A Study into the Causes and Catalysts of the German Economic Miracle
The purpose of this paper is to analyze the West German economy to find the reason for “Wirtschaftswunder,” the German economic miracle, and contrast the decisions made after WWII to those made after WWI. The approaches of foreign powers in these periods are also analyzed. After WWI, the subsequent hyperinflation and economic collapse is mainly found to be a result of poor economic decisions within German institutions, although the collapse was almost certainly supplemented by poor foreign policy decisions by the Allied Powers. Wirtschaftswunder was made possible by Ludwig Erhard’s reforms, which are found to have been much more important to West Germany’s success and successful denazification than the Marshall Plan. The best plan for economic recovery for Germany was one of least economic interference. In the years immediately following WWII, the Allied Powers were extremely influential in governmental institutions, but this was only to help stabilize the devastated country for a short period of time after the war and help rebuild its political institutions so it could return to self-governance. West Germany’s economy was allowed to grow, unhindered by large reparations payments, catching up to its productivity capacity that was never truly eliminated by Allied bombing during the war
A Universal Stellar Initial Mass Function? A Critical Look at Variations
Few topics in astronomy initiate such vigorous discussion as whether or not
the initial mass function (IMF) of stars is universal, or instead sensitive to
the initial conditions of star formation. The distinction is of critical
importance: the IMF influences most of the observable properties of stellar
populations and galaxies, and detecting variations in the IMF could provide
deep insights into the process by which stars form. In this review, we take a
critical look at the case for IMF variations, with a view towards whether other
explanations are sufficient given the evidence. Studies of the field, local
young clusters and associations, and old globular clusters suggest that the
vast majority were drawn from a "universal" IMF: a power-law of Salpeter index
() above a few solar masses, and a log normal or shallower
power-law () between a few tenths and a few solar masses
(ignoring the effects of unresolved binaries). The shape and universality of
the IMF at the stellar-substellar boundary is still under investigation and
uncertainties remain large, but most observations are consistent with a IMF
that declines () well below the hydrogen burning limit.
Observations of resolved stellar populations and the integrated properties of
most galaxies are also consistent with a "universal IMF", suggesting no gross
variations in the IMF over much of cosmic time. There are indications of
"non-standard" IMFs in specific local and extragalactic environments, which
clearly warrant further study. Nonetheless, there is no clear evidence that the
IMF varies strongly and systematically as a function of initial conditions
after the first few generations of stars.Comment: 49 pages, 5 figures, to appear in Annual Reviews of Astronomy and
Astrophysics (2010, volume 48
Recent Results and Perspectives for Precision Astrometry and Photometry with Adaptive Optics
Large ground-based telescopes equipped with adaptive optics (AO) systems have
ushered in a new era of high-resolution infrared photometry and astrometry.
Relative astrometric accuracies of <0.2 mas have already been demonstrated from
infrared images with spatial resolutions of 55-95 mas resolution over 10-20''
fields of view. Relative photometric accuracies of 3% and absolute photometric
accuracies of 5%-20% are also possible. I will review improvements and current
limitations in astrometry and photometry with adaptive optics of crowded
stellar fields. These capabilities enable experiments such as measuring orbits
for brown dwarfs and exoplanets, studying our Galaxy's supermassive black hole
and its environment, and identifying individual stars in young star clusters,
which can be used test the universality of the initial mass function.Comment: SPIE Conference Proceedin
Kinematic Masses of Super Star Clusters in M82 from High-Resolution Near-Infrared Spectroscopy
Using high-resolution (R~22,000) near-infrared (1.51 -- 1.75 microns) spectra
from Keck Observatory, we measure the kinematic masses of two super star
clusters in M82. Cross-correlation of the spectra with template spectra of cool
evolved stars gives stellar velocity dispersions of sigma_r=15.9 +/- 0.8 km/s
for MGG-9 and sigma_r=11.4 +/- 0.8 km/s for MGG-11. The cluster spectra are
dominated by the light of red supergiants, and correlate most closely with
template supergiants of spectral types M0 and M4.5. We fit King models to the
observed profiles of the clusters in archival HST/NICMOS images to measure the
half-light radii. Applying the virial theorem, we determine masses of 1.5 +/-
0.3 x 10^6 M_sun for MGG-9 and 3.5 +/- 0.7 x 10^5 M_sun for MGG-11. Population
synthesis modelling suggests that MGG-9 is consistent with a standard initial
mass function, whereas MGG-11 appears to be deficient in low-mass stars
relative to a standard IMF. There is, however, evidence of mass segregation in
the clusters, in which case the virial mass estimates would represent lower
limits.Comment: 16 pages, 8 figures; ApJ, in pres
Using an Initiative to Focus Programming Efforts: A Case Study of the Ohio 4-H Workforce Preparation Initiative
Extension is facing many challenges, including increasingly complex and changing societal conditions. One method to address these challenges is to implement targeted efforts around programmatic or organizational themes organized as an initiative. We use the Ohio 4-H Workforce Preparation Initiative as a case study to illustrate how the process of focusing and redirecting programming efforts can be an effective strategy for addressing issues important to Extension clientele. We also describe in general the benefits of using a change process or model to organize such efforts and specifically how Kotter\u27s (1996) model fits well with our concept of an initiative
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