1,951 research outputs found
Inflation and unemployment: a layperson's guide to the Phillips curve
Inflation (Finance) ; Unemployment ; Phillips curve
Takeovers and stock price volatility
An examination of the relation between takeovers and stock price volatility. The analysis focuses on the Martingale (efficient markets) Model of stock price behavior and an alternative view in which stock prices reflect values to participants in a market for corporate control. This paper includes a mathematical treatment of the subject.Stock - Prices
Now how large is the safety net?
According to estimates done by researchers at the Richmond Fed, the federal financial safety net covered $25 trillion in liabilities, or 59 percent of all financial liabilities, at the end of 2008. Such expansion of the safety net has weakened market discipline and contributed to instability in the financial sector. Instead of attempting to address the "too big to fail" problem by breaking up large firms, for instance, policymakers ought to focus on credibly scaling back the safety net and making its boundaries transparent.Financial markets
The Fed's entry into check clearing reconsidered
Check collection systems ; Federal Reserve System
The Upper East Side vs Central Harlem: What is responsible for the Dermatology Disparities that shaped these Communities?
Very few studies have been done to understand why there is a paucity of dermatology practices in the Central Harlem (CH) community in Manhattan. This ecological and exploratory study will identify factors such as, geographical location, race, socioeconomic status, health care and medical education, as reasons why there is a disparity between the dermatology services in the CH community versus the Upper East Side (UES) of Manhattan. Thus, examining the differences in the neighborhoods as a mediator, it is hypothesized there is a need for increased dermatology practices to CH, as not catering to the clinical needs of a community can be detrimental to the public health and welfare of its residents. Therefore, initiatives like; improved medical education among dermatology residents, dermatology outreach, incentives to open dermatology practices in CH and free dermatology clinics are a few ideas, which can be implemented to help close this disparity gap
The Nature of Lyman Break Galaxies in Cosmological Hydrodynamic Simulations
What type of objects are being detected as "Lyman break galaxies"?
Are they predominantly the most massive galaxies at that epoch, or are many of
them smaller galaxies undergoing a short-lived burst of merger-induced star
formation? We attempt to address this question using high-resolution
cosmological hydrodynamic simulations including star formation and feedback.
Our CDM simulation, together with Bruzual-Charlot population synthesis
models, reproduces the observed number density and luminosity function of Lyman
break galaxies when dust is incorporated. The inclusion of dust is crucial for
this agreement. In our simulation, these galaxies are predominantly the most
massive objects at this epoch, and have a significant population of older
stars. Nevertheless, it is possible that our simulations lack the resolution
and requisite physics to produce starbursts, despite having a physical
resolution of \la 700 pc at z=3. Thus we cannot rule out merger-induced
starburst galaxies also contributing to the observed population of
high-redshift objects.Comment: 5 pages, contribution to the Proceedings of Rencontres
Internationales de l'IGRAP, Clustering at High Redshift, Marseille 199
Theoretical Modeling of the High Redshift Galaxy Population
We review theoretical approaches to the study of galaxy formation, with
emphasis on the role of hydrodynamic simulations in modeling the high redshift
galaxy population. We present new predictions for the abundance of star-forming
galaxies in the Lambda + cold dark matter model (Omega_m=0.4, Omega_L=0.6),
combining results from several simulations to probe a wide range of redshift.
At a threshold density of one object per arcmin^2 per unit z, these simulations
predict galaxies with star formation rates of 2 msun/yr (z=10), 5 msun/yr
(z=8), 20 msun/yr (z=6), 70-100 msun/yr (z=4-2), and 30 msun/yr (z=0.5). For
galaxies selected at a fixed comoving space density n=0.003 h^3 Mpc^{-3], a (50
Mpc/h)^3 simulation predicts a galaxy correlation function (r/5 Mpc/h)^{-1.8}
in comoving coordinates, essentially independent of redshift from z=4 to z=0.5.
Different cosmological models predict global histories of star formation that
reflect their overall histories of mass clustering, but robust numerical
predictions of the comoving space density of star formation are difficult
because the simulations miss the contribution from galaxies below their
resolution limit. The LCDM model appears to predict a star formation history
with roughly the shape inferred from observations, but it produces too many
stars at low redshift, predicting Omega_* ~ 0.015 at z=0. We conclude with a
brief discussion of this discrepancy and three others that suggest gaps in our
current theory of galaxy formation: small disks, steep central halo profiles,
and an excess of low mass dark halos. While these problems could fade as the
simulations or observations improve, they could also guide us towards a new
understanding of galactic scale star formation, the spectrum of primordial
fluctuations, or the nature of dark matter.Comment: 12 pages, 3 figs. To be published in "Photometric Redshifts and High
Redshift Galaxies", eds. R. Weymann, L. Storrie-Lombardi, M. Sawicki & R.
Brunner, (San Francisco: ASP Conference Series
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