6,628 research outputs found
Generalized wordlength patterns and strength
Xu and Wu (2001) defined the \emph{generalized wordlength pattern} of an arbitrary fractional factorial design (or orthogonal array) on
factors. They gave a coding-theoretic proof of the property that the design
has strength if and only if . The quantities are
defined in terms of characters of cyclic groups, and so one might seek a direct
character-theoretic proof of this result. We give such a proof, in which the
specific group structure (such as cyclicity) plays essentially no role.
Nonabelian groups can be used if the counting function of the design satisfies
one assumption, as illustrated by a couple of examples
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Federal Programs Available to Unemployed Workers
[Excerpt] Four groups of federal programs target unemployed workers: unemployment insurance, health care assistance, job search assistance, and training. This report presents information on federal programs targeted to unemployed workers specifically, but does not attempt to discuss means-tested programs (such as Medicaid or SSI) that are available regardless of employment status.
This report will be updated with major new legislation
Estimation of the geophysical properties of the ocean surface using aircraft microwave measurements
An improved model of the effects of sea state on microwave signature has been developed which incorporates the different effects of whitecaps and streaks to define the response of microwave channels to wind speed. This model has been demonstrated to agree with recent measurements. An approximation model has also been incorporated to describe the effects of precipitation on microwave radiation through a computationally rapid routine. The use of these models and a new technique to allow the selection of the most climatologically appropriate D-matrix is demonstrated in the inversion of data collected over the bering Sea. Surface wind speed agrees very well with observations while good results are obtained for integrated water vapor, and liquid water
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Federal Programs Available to Unemployed Workers
[Excerpt] Four groups of federal programs target unemployed workers: unemployment insurance programs, health care assistance, job search assistance, and training. This report describes these programs, how they interact with each other, and their funding.
Unemployed workers and their families may experience substantial income loss. If the unemployed worker’s family income is low enough, there are a number of means-tested benefits and programs for which the unemployed worker’s family might qualify (e.g., Temporary Assistance for Needy Families, SSI, or Medicaid). Eligibility for such benefits is not conditional on an individual’s current employment status. This report does not attempt to discuss these means-tested benefits and programs
Patterns of gene expression in schistosomes: localization by whole mount in situ hybridization
rom the identification of genes to the characterization of their functions and interactions. Developmental biologists have long used whole mount in situ hybridization (WISH) to determine gene expression patterns, as a vital tool for formulating and testing hypotheses about function. This paper describes the application of WISH to the study of gene expression in larval and adult schistosomes. Fixed worms were permeablized by proteinase K treatment for hybridization with digoxygenin-labelled RNA probes, with binding being detected by alkaline phosphatase-coupled anti-digoxygenin antibodies, and BM Purple substrate. Discrete staining patterns for the transcripts of the molecules Sm29, cathepsin L, antigen 10.3 and chorion were observed in the tegument cell bodies, gut epithelium, oesophageal gland and vitelline lobules, respectively, of adult worms. Transcripts of the molecules SGTP4, GP18-22 and cathepsin L were localized to tegument cell bodies and embryonic gut, respectively, of lung schistosomula. We also showed that Fast Red TR fluorescent substrate can refine the pattern of localization permitting use of confocal microscopy. We believe that method of WISH will find broad application, in synergy with other emerging post-genomic techniques, such as RNA interference, to studies focused at increasing our molecular understanding of schistosomes
Antiferromagnetic Domain Wall Engineering in Chromium Films
We have engineered an antiferromagnetic domain wall by utilizing a magnetic
frustration effect of a thin iron cap layer deposited on a chromium film.
Through lithography and wet etching we selectively remove areas of the Fe cap
layer to form a patterned ferromagnetic mask over the Cr film. Removing the Fe
locally removes magnetic frustration in user-defined regions of the Cr film. We
present x-ray microdiffraction microscopy results confirming the formation of a
90{\deg} spin-density wave propagation domain wall in Cr. This domain wall
nucleates at the boundary defined by our Fe mask.Comment: submitted to AP
Interplay of charge and spin correlations in nickel perovskites
Analyzing the motion of low--spin holes in a high--spin
background, we derive a sort of generalized t--J Hamiltonian for the planes of Sr--doped nickelates. In addition to the rather complex
carrier--spin and spin--spin couplings we take into account the coupling of the
doped holes to in--plane oxygen breathing modes by a Holstein--type interaction
term. Because of strong magnetic confinement effects the holes are nearly
entirely prelocalized and the electron--phonon coupling becomes much more
effective in forming polarons than in the isostructural cuprates. In the light
of recent experiments on we discuss how the variety of
the observed transport and charge/spin--ordering phenomena can be qualitatively
understood in terms of our model Hamiltonian.Comment: 2 pages, LTpaper.sty, Proc. XXI Int. Conf. on Low Temp. Phys. Prague
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Structures and functions of carotenoids bound to reaction centers from purple photosynthetic bacteria
The photoprotective function of 15,15'-cis-carotenoids bound to the photosynthetic reaction centers (RCs) of purple bacteria has been studied using carotenoids reconstituted into carotenoidless RCs from Rhodobacter sphaeroides strain R26.1. The triplet-energy level of the carotenoid has been proposed to affect the quenching of the triplet state of special-pair bacteriochlorophyll (P). This was investigated using microsecond flash photolysis to detect the carotenoid triplets as a function of the number of conjugated double bonds, n. The carotenoid triplet signals were extracted by using singular-value decomposition (SVD) of the huge matrices data, and were confirmed for those having n = 8 to 11. This interpretation assumes that the reconstituted carotenoids occupy the same binding site in the RC. We have been able to confirm this assumption using X-ray crystallography to determine the structures of carotenoidless, wild-type carotenoid-containing, and 3,4-dihydro-spheroidene-reconstituted RCs. The X-ray study also emphasized the importance of the methoxy group of the carotenoids for binding to the RCs. Electroabsorption (Stark) spectroscopy was used to investigate the effect of the carotenoid on the electrostatic field around P. This electrostatic field changed by 10 % in the presence of the carotenoid
Observing the Symmetry of Attractors
We show how the symmetry of attractors of equivariant dynamical systems can
be observed by equivariant projections of the phase space. Equivariant
projections have long been used, but they can give misleading results if used
improperly and have been considered untrustworthy. We find conditions under
which an equivariant projection generically shows the correct symmetry of the
attractor.Comment: 28 page LaTeX document with 9 ps figures included. Supplementary
color figures available at http://odin.math.nau.edu/~jws
Resonant Inelastic X-Ray Scattering from Valence Excitations in Insulating Copper-Oxides
We report resonant inelastic x-ray measurements of insulating LaCuO
and SrCuOCl taken with the incident energy tuned near the Cu K
absorption edge. We show that the spectra are well described in a shakeup
picture in 3rd order perturbation theory which exhibits both incoming and
outgoing resonances, and demonstrate how to extract a spectral function from
the raw data. We conclude by showing {\bf q}-dependent measurements of the
charge transfer gap.Comment: minor notational changes, discussion of anderson impurity model
fixed, references added; accepted by PR
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