5,987 research outputs found
The Shane Wirtanen counts: Observability of the galaxy correlation function
For an explicit test of the ability to recover the galaxy two-point correlation function from the Lick catalog of Shane and Wirtanen, we have applied the reduction and analysis methods of Seidner et al. and Groth and Peebles to model galaxy distributions that have known plate and field "errors" and that are high-fidelity simulations of the Lick sample. The model galaxy space distribution is constructed with the Soneira-Peebles prescription, which generates model distributions which have two-, three-, and four-point correlation functions in good agreement with the observed correlation functions. The space distribution is projected onto the sky with and without plate "errors." The Seidner et al. analysis recovers the plate factors in the former case with an error of 6.3%, as originally estimated. The two-point correlation function estimated from the "corrected" model catalog reproduces the built-in correlation function including the break from the power law. This is also true if the angular scale of the break is increased or decreased by a factor of 1.76 from the observed
value. We also compare a map of the corrected counts with a map of the counts projected without plate errors and find that the corrected map is a good visual representation of the galaxy distribution. Finally, we construct a simulation which includes systematic variations in plate sensitivity with observer and time-so called "plate shape gradients." Once again, the correlation function of the model catalog reproduces the built in correlation function
The Effects of Surface Disturbances on the Leaching of Heavy Metals
The harmful effects of heavy metal contamination of
surface waters impacted by gold mining activity are well
documented. An examination was conducted on the effects of
surface disturbances in Wade Creek on the concentrations
of heavy metals in solution, and whether Thiobacillus
ferrooxidans, a bacteria found in heavy metal contaminated
drainages from placer mines, is found in the drainage.
Thiobacillus ferrooxidans was not detected in this
particular setting. The effects of mining activity and relandscaping
of stockpiled tailings showed in a short
distance, a net increase of dissolved arsenic, copper,
zinc, and iron. However, the long distance impact of
dissolved metals was minimal. Generally, it seems that the
dampening of the total suspended solids had a direct
effect on the removal of metals dissolved in solution.The research on which the report is based was financed in part by the
United States Department of the Interior, Geological Survey, through
grant number 14-08-0001-61313 to the Water Research Center
Non-Cointegration and Econometric Evaluation of Models of Regional Shift and Share
This paper tests for cointegration between regional output of an industry and national output of the same industry. An equilibrium economic theory is presented to argue for the plausibility of cointegration, however, regional economic forecasting using the shift and share framework often acts as if cointegration does not exist. Data analysis on broad industrial sectors for 20 states finds very little evidence for cointegration. Forecasting models with and without imposing cointegration are than constructed and used to forecast out of sample. The simplest, non-cointegrating models are the best.
Deep crustal heating by neutrinos from the surface of accreting neutron stars
We present a new mechanism for deep crustal heating in accreting neutron
stars. Charged pions () are produced in nuclear collisions on the
neutron star surface during active accretion and upon decay they provide a flux
of neutrinos into the neutron star crust. For massive and/or compact neutron
stars, neutrinos deposit of heat per
accreted nucleon into the inner crust. The strength of neutrino heating is
comparable to the previously known sources of deep crustal heating, such as
from pycnonuclear fusion reactions, and is relevant for studies of cooling
neutron stars. We model the thermal evolution of a transient neutron star in a
low-mass X-ray binary, and in the particular case of the neutron star
MXB~1659-29 we show that additional deep crustal heating requires a higher
thermal conductivity for the neutron star inner crust. A better knowledge of
pion production cross sections near threshold would improve the accuracy of our
predictions.Comment: 12 pages, 9 figures, 3 tables; [Added a new figure and edited the
text in response to Referee's remarks and suggestions
Microbial ecology of Thiobacillus ferrooxidans
FINAL TECHNICAL REPORT
TO
U.S. DEPARTMENT OF THE INTERIOR
Geological Survey
Washington. D.C.The contents of this report were developed in part under a grant from
the Department of the Interior, U.S. Geological Survey. Grant number 14-08-0001-61313
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