5,756 research outputs found
Application of maximum entropy optimal projection design synthesis to a benchmark problem
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76995/1/AIAA-20955-739.pd
Recommended from our members
Initial Report on the Geology of the Northeastern Part of the New Braunfels, Texas
This brief report describes initial progress on geologic mapping and paleontologic studies that are being conducted in the vicinity of New Braunfels, Texas. The primary objective of this work is to produce an accurate geologic map that will be printed on the new 1:100,000-scale map of the New Braunfels, Texas, 30 X 60 minute quadrangle, which is in preparation by the U.S. Geological Survey. A planimetric version has been printed, but the final topographic map is not yet available. Our initial mapping has been completed on 1:24,000-scale topographic maps and is intended for compilation at 1:100,000-scale. Partial funding for the second year of the study has been approved. Work during year two will continue the mapping into quadrangles adjacent to those mapped in year one. Paleontologic work by Dr. Will Elder will continue as part of the in-kind contribution by the U.S. Geological Survey to this effort. Dr. E. G. Wermund has described this project to several groups for whom the geology of this area is of interest. Draft copies of the mapping accomplished to date have been given to the Edwards Underground Water District, potentially for entry by them into a GIS, and copies will be made available to other interested parties as requested. In addition, the South Texas Geological Society has passed a resolution commending this initiative, supporting this new mapping effort, and offering the help of their membership.Bureau of Economic Geolog
Maximum entropy controller synthesis for colocated and noncolocated systems
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77185/1/AIAA-21277-539.pd
Applications of aerospace technology to petroleum extraction and reservoir engineering
Through contacts with the petroleum industry, the petroleum service industry, universities and government agencies, important petroleum extraction problems were identified. For each problem, areas of aerospace technology that might aid in its solution were also identified, where possible. Some of the problems were selected for further consideration. Work on these problems led to the formulation of specific concepts as candidate for development. Each concept is addressed to the solution of specific extraction problems and makes use of specific areas of aerospace technology
Lifelongα-tocopherol supplementation increases the median life span of C57BL/6 mice in the cold but has only minor effects on oxidative damage
The effects of dietary antioxidant supplementation on oxidative stress and life span are confused. We maintained C57BL/6 mice at 7 ± 2°C and supplemented their diet with α-tocopherol from 4 months of age. Supplementation significantly increased (p = 0.042) median life span by 15% (785 days, n = 44) relative to unsupplemented controls (682 days, n = 43) and also increased maximum life span (oldest 10%, p = 0.028). No sex or sex by treatment interaction effects were observed on life span, with treatment having no effect on resting or daily metabolic rate. Lymphocyte and hepatocyte oxidative DNA damage and hepatic lipid peroxidation were unaffected by supplementation, but hepatic oxidative DNA damage increased with age. Using a cDNA macroarray, genes associated with xenobiotic metabolism were significantly upregulated in the livers of female mice at 6 months of age (2 months supplementation). At 22 months of age (18 months supplementation) this response had largely abated, but various genes linked to the p21 signaling pathway were upregulated at this time. We suggest that α-tocopherol may initially be metabolized as a xenobiotic, potentially explaining why previous studies observe a life span extension generally when lifelong supplementation is initiated early in life. The absence of any significant effect on oxidative damage suggests that the life span extension observed was not mediated via any antioxidant properties of α-tocopherol. We propose that the life span extension observed following α-tocopherol supplementation may be mediated via upregulation of cytochrome p450 genes after 2 months of supplementation and/or upregulation of p21 signaling genes after 18 months of supplementation. However, these signaling pathways now require further investigation to establish their exact role in life span extension following α-tocopherol supplementation
Parallel Mapper
The construction of Mapper has emerged in the last decade as a powerful and
effective topological data analysis tool that approximates and generalizes
other topological summaries, such as the Reeb graph, the contour tree, split,
and joint trees. In this paper, we study the parallel analysis of the
construction of Mapper. We give a provably correct parallel algorithm to
execute Mapper on multiple processors and discuss the performance results that
compare our approach to a reference sequential Mapper implementation. We report
the performance experiments that demonstrate the efficiency of our method
On the breaking of collinear factorization in QCD
We investigate the breakdown of collinear factorization for non-inclusive
observables in hadron-hadron collisions. For pure QCD processes, factorization
is violated at the three-loop level and it has a structure identical to that
encountered previously in the case of super-leading logarithms. In particular,
it is driven by the non-commutation of Coulomb/Glauber gluon exchanges with
other soft exchanges. Beyond QCD, factorization may be violated at the two-loop
level provided that the hard subprocess contains matrix element contributions
with phase differences between different colour topologies.Comment: Version 2: minor improvements for journal publicatio
The KLN Theorem and Soft Radiation in Gauge Theories: Abelian Case
We present a covariant formulation of the Kinoshita, Lee, Nauenberg (KLN)
theorem for processes involving the radiation of soft particles. The role of
the disconnected diagrams is explored and a rearrangement of the perturbation
theory is performed such that the purely disconnected diagrams are factored
out. The remaining effect of the disconnected diagrams results in a simple
modification of the usual Feynman rules for the S-matrix elements. As an
application, we show that when combined with the Low theorem, this leads to a
proof of the absense of the corrections to inclusive processes (like the
Drell-Yan process). In this paper the abelian case is discussed to all orders
in the coupling.Comment: 27 pages, LaTeX, 14 figure
Benchmark problems for robust control design
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76996/1/AIAA-20949-475.pd
Loose Groups of Galaxies in the Las Campanas Redshift Survey
A ``friends-of-friends'' percolation algorithm has been used to extract a
catalogue of dn/n = 80 density enhancements (groups) from the six slices of the
Las Campanas Redshift Survey (LCRS). The full catalogue contains 1495 groups
and includes 35% of the LCRS galaxy sample. A clean sample of 394 groups has
been derived by culling groups from the full sample which either are too close
to a slice edge, have a crossing time greater than a Hubble time, have a
corrected velocity dispersion of zero, or contain a 55-arcsec ``orphan'' (a
galaxy with a mock redshift which was excluded from the original LCRS redshift
catalogue due to its proximity to another galaxy -- i.e., within 55 arcsec).
Median properties derived from the clean sample include: line-of-sight velocity
dispersion sigma_los = 164km/s, crossing time t_cr = 0.10/H_0, harmonic radius
R_h = 0.58/h Mpc, pairwise separation R_p = 0.64/h Mpc, virial mass M_vir =
(1.90x10^13)/h M_sun, total group R-band luminosity L_tot = (1.30x10^11)/h^2
L_sun, and R-band mass-to-light ratio M/L = 171h M_sun/L_sun; the median number
of observed members in a group is 3.Comment: 32 pages of text, 27 figures, 7 tables. Figures 1, 4, 6, 7, and 8 are
in gif format. Tables 1 and 3 are in plain ASCII format (in paper source) and
are also available at http://www-sdss.fnal.gov:8000/~dtucker/LCLG . Accepted
for publication in the September 2000 issue of ApJ
- …