2,508 research outputs found
What is the Natural Size of Supersymmetric Violation?
It is well known that if phases and masses in the Minimal Supersymmetric
Standard Model (MSSM) are allowed to have general values, the resulting neutron
EDM () exceeds the experimental upper limit by about . We assume
that the needed suppression is not due to a fine-tuning of phases or masses,
and ask what natural size of violation (CPV) results. We show that (1) the
phase of one of the superpotential parameters, , does not contribute to
any CPV in the MSSM and so is not constrained by \dn; (2) the MSSM contribution
to is tiny, just coming from the CKM phase; (3) the phases in the MSSM
cannot be used to generate a baryon asymmetry at the weak scale, given our
assumptions; and (4) in non-minimal SUSY models, an effective phase can enter
at one loop giving \ecm, \ecm, and
allowing a baryon asymmetry to be generated at the weak scale, without
fine-tunings. Our results could be evaded by a SUSY breaking mechanism which
produced phases for the SUSY breaking parameters that somehow were naturally of
order .Comment: 13pp (no figs), REVTEX (LATEX), TRI-PP-93-
Knowledge Economy Immigration: A Priority for U.S. Growth Policy
Offers economic and political arguments for facilitating immigration of highly educated, skilled workers as a way to support long-term knowledge-based economic growth. Proposes granting green cards to math and science graduates of qualified U.S. colleges
Hydrology of the Central Arctic River Basins of Alaska
The work upon which this report is based was supported in part by funds (Project A-031-ALAS) provided by the United States Department
of Interior, Office of Water Resources Research, as authorized under
the Water Resources Act of 1964, as amended
Measuring Risk Aversion From Excess Returns on a Stock Index
We distinguish the measure of risk aversion from the slope coefficient in the linear relationship between the mean excess return on a stock index and its variance. Even when risk aversion is constant, the latter can vary significantly with the relative share of stocks in the risky wealth portfolio, and with the beta of unobserved wealth on stocks. We introduce a statistical model with ARCH disturbances and a time-varying parameter in the mean (TVP ARCH-N). The model decomposes the predictable component in stock returns into two parts: the time-varying price of volatility and the time-varying volatility of returns. The relative share of stocks and the beta of the excluded components of wealth on stocks are instrumented by macroeconomic variables. The ratio of corporate profit over national income and the inflation rate ore found to be important forces in the dynamics of stock price volatility.
Effects of seasonability and variability of streamflow on nearshore coastal areas: final report
General nature and scope of the study:
This study examines the variability of streamflow in all
gaged Alaskan rivers and streams which terminate in the ocean.
Forty-one such streams have been gaged for varying periods of
time by the U. S. Geological Survey, Water Resources Division.
Attempts have been made to characterize streamflow statistically
using standard hydrological methods. The analysis scheme
which was employed is shown in the flow chart which follows.
In addition to the statistical characterization, the following
will be described for each stream when possible:
1. average period of break-up initiation (10-day period)
2. average period of freeze-up (10-day period)
3. miscellaneous break-up and freeze-up data.
4. relative hypsometric curve for each basin
5. observations on past ice-jam flooding
6. verbal description of annual flow variation
7. original indices developed in this study to relate streamflow
variability to basin characteristics and regional
climate.This study was supported under contract 03-5-022-56, Task Order
#4, Research Unit #111, between the University of Alaska and NOAA,
Department of Commerce to which funds were provided by the Bureau of
Land Management through an interagency agreement
How Big is the Tax Advantage to Debt?
This paper uses an option valuation model of the firm to answer the question, "What magnitude tax advantage to debt is consistent with the range of observed corporate debt ratios?" We incorporate into the model differential personal tax rates on capital gains and ordinary income. We conclude that variations in the magnitude of bankruptcy costs across firms can not by itself account for the simultaneous existence of levered and unlevered firms. When it is possible for the value of the underlying assets to junip discretely to zero, differences across firms in the probability of this jump can account for the simultaneous existence of levered and unlevered firms. Moreover, if the tax advantage to debt is small, the annual rate of return advantage offered by optimal leverage may be so small as to make the firm indifferent about debt policy over a wide range of debt-to-firm value ratios.
Debt Policy and the Rate of Return Premium to Leverage
Equilibrium in the market for real assets requires that the price of those assets be bid up to reflect the tax shields they can offer to levered firms.Thus there must be an equality between the market values of real assets and the values of optimally levered firms. The standard measure of the advantage to leverage compares the values of levered and unlevered assets, and can be misleading and difficult to interpret. We show that a meaningful measure of the advantage to debt is the extra rate of return, net of a market premium for bankruptcy risk, earned by a levered firm relative to an otherwise-identical unlevered firm. We construct an option valuation model to calculate such a measure and present extensive simulation results. We use this model to compute optimal debt maturities, show how this approach can be used for capital budgeting, and discuss its implications for the comparison of bankruptcy costs versus tax shields.
Central Limit Theorems for some Set Partition Statistics
We prove the conjectured limiting normality for the number of crossings of a
uniformly chosen set partition of [n] = {1,2,...,n}. The arguments use a novel
stochastic representation and are also used to prove central limit theorems for
the dimension index and the number of levels
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