1,756 research outputs found
On vote-taking and complete decoding of certain error-correcting codes
It is shown how complete decoding of maximum distance separable codes can be accomplished by a vote-taking algorithm or an equivalent distance correlation method. It is also indicated where this method of decoding might find application
Pennsylvania v. Conroy: Expanded Administrative Expense Priority for State-Funded CERCLA Cleanups Note
In Pennsylvania v. Conroy, the United States Court of Appeals for the Third Circuit affirmed the decision of the United States District Court for the Western District of Pennsylvania. The court held that cleanup expenses incurred by a state environmental agency to remove the threat posed by hazardous wastes should be treated as administrative expenses under the Bankruptcy Code. Thus, the Third Circuit afforded state response costs high priority when the assets of the bankruptcy estate were distributed. In addition, this case expanded prior decisions by holding that administrative and legal costs incurred by a state agency, usually around 10% of the total costs, should also be awarded to the agency. This expansion is the most important contribution of Conroy. This paper will suggest amending the Bankruptcy Code to include an express administrative expense priority for hazardous waste remediation. Such an amendment is necessary, since neither the courts nor Congress has resolved the issue. Since 1986, however, the trend in the federal circuit courts has been toward affording state cleanup costs a high priority
Detection of large scale intrinsic ellipticity-density correlation from the Sloan Digital Sky Survey and implications for weak lensing surveys
The power spectrum of weak lensing shear caused by large-scale structure is
an emerging tool for precision cosmology, in particular for measuring the
effects of dark energy on the growth of structure at low redshift. One
potential source of systematic error is intrinsic alignments of ellipticities
of neighbouring galaxies (II correlation) that could mimic the correlations due
to lensing. A related possibility pointed out by Hirata and Seljak (2004) is
correlation between the intrinsic ellipticities of galaxies and the density
field responsible for gravitational lensing shear (GI correlation). We present
constraints on both the II and GI correlations using 265 908 spectroscopic
galaxies from the SDSS, and using galaxies as tracers of the mass in the case
of the GI analysis. The availability of redshifts in the SDSS allows us to
select galaxies at small radial separations, which both reduces noise in the
intrinsic alignment measurement and suppresses galaxy- galaxy lensing (which
otherwise swamps the GI correlation). While we find no detection of the II
correlation, our results are nonetheless statistically consistent with recent
detections found using the SuperCOSMOS survey. In contrast, we have a clear
detection of GI correlation in galaxies brighter than L* that persists to the
largest scales probed (60 Mpc/h) and with a sign predicted by theoretical
models. This correlation could cause the existing lensing surveys at z~1 to
underestimate the linear amplitude of fluctuations by as much as 20% depending
on the source sample used, while for surveys at z~0.5 the underestimation may
reach 30%. (Abridged.)Comment: 16 pages, matches version published in MNRAS (only minor changes in
presentation from original version
Precision Cosmology from the Lyman-alpha Forest: Power Spectrum and Bispectrum
We investigate the promise of the Ly-alpha forest for high precision
cosmology in the era of the Sloan Digital Sky Survey using low order N-point
statistics. We show that with the existing data one can determine the
amplitude, slope and curvature of the slope of the matter power spectrum with a
few percent precision. Higher order statistics such as the bispectrum provide
independent information that can confirm and improve upon the statistical
precision from the power spectrum alone. The achievable precision is comparable
to that from the cosmic microwave background with upcoming satellites, and
complements it by measuring the power spectrum amplitude and shape at smaller
scales. Since the data cover the redshift range 2<z<4, one can also extract the
evolution of the growth factor and Hubble parameter over this range, and
provide useful constraints on the presence of dark energy at z>2.Comment: 14 pages, 17 figures, accepted to MNRAS; minor changes made (section
2) and references adde
Anaerobes and short-chain fatty acids in crevicular fluid from adults with chronic periodontitis
Pathogeny of adult chronic periodontitis is still unclear. Bacteriological and chemical analysis of crevicular fluid have shown, in active sites of the disease, a simultaneous presence of anaerobes and their major by-product: short-chain fatty acids. The last can decrease «in vitro» the neutrophil intracellular pH, whenever these cells are incubated in an acid medium. Clinical investigations are scarce which hold out data useful to attempt verifying this possible physiopathological mechanism. This work shows the presence of anaerobes in the active periodontal pockets, together with the presence of short-chain fatty acids likely to reach a concentration level comparable to that used for inhibiting neutrophils «in vitro».Forthcoming studies should investigate about a possible intracellular pH drop in the neutrophils and other cells of the inflamed periodontium.La pathogĂ©nie des parodontites chroniques de lâadulte nâest pas encore bien comprise. Des analyses bactĂ©riologiques et chimiques du liquide crĂ©viculaire ont permis de mettre en Ă©vidence, dans des sites actifs de la maladie, des germes anaĂ©robies et leurs principaux produits cataboliques: les acides gras Ă courte chaĂźne.Ceux-ci peuvent rĂ©duire «in vitro» le pH intracellulaire des neutrophiles en suspension dans un tampĂłn acide. Peu dâĂ©tudes prĂ©sentent des donnĂ©es cliniques permettant de vĂ©rifier «in vivo» cet Ă©ventuel mĂ©canisme physiopathologique. Ce travail montre la prĂ©sence simultanĂ©e, dans des poches parodontales, de germes anaĂ©robies et dâacides gras Ă courte chaĂźne Ă des concentrations similaires Ă celles utilisĂ©es pour inhiber «in vitro» des neutrophiles. Dâautres travaux devront Ă©tudier la chute Ă©ventuelle du pH intracellulaire des cellules du parodonte en Ă©tat dâinflammation chronique
Ring-type singular solutions of the biharmonic nonlinear Schrodinger equation
We present new singular solutions of the biharmonic nonlinear Schrodinger
equation in dimension d and nonlinearity exponent 2\sigma+1. These solutions
collapse with the quasi self-similar ring profile, with ring width L(t) that
vanishes at singularity, and radius proportional to L^\alpha, where
\alpha=(4-\sigma)/(\sigma(d-1)). The blowup rate of these solutions is
1/(3+\alpha) for 4/d\le\sigma<4, and slightly faster than 1/4 for \sigma=4.
These solutions are analogous to the ring-type solutions of the nonlinear
Schrodinger equation.Comment: 21 pages, 13 figures, research articl
The Masses and Shapes of Dark Matter Halos from Galaxy-Galaxy Lensing in the CFHTLS
We present the first galaxy-galaxy weak lensing results using early data from
the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). These results are
based on ~22 sq. deg. of i' data. From this data, we estimate the average
velocity dispersion for an L* galaxy at a redshift of 0.3 to be 137 +- 11 km/s,
with a virial mass, M_{200}, of 1.1 +- 0.2 \times 10^{12} h^{-1} Msun and a
rest frame R-band mass-to-light ratio of 173 +- 34 h Msun/Lsun. We also
investigate various possible sources of systematic error in detail.
Additionally, we separate our lens sample into two sub-samples, divided by
apparent magnitude, thus average redshift. From this early data we do not
detect significant evolution in galaxy dark matter halo mass-to-light ratios
from a redshift of 0.45 to 0.27. Finally, we test for non-spherical galaxy dark
matter halos. Our results favor a dark matter halo with an ellipticity of ~0.3
at the 2-sigma level when averaged over all galaxies. If the sample of
foreground lens galaxies is selected to favor ellipticals, the mean halo
ellipticity and significance of this result increase.Comment: 12 pages, 11 figures, accepted to ApJ, uses emulateap
Detection of intrinsic cluster alignments to 100 Mpc/h in the SDSS
We measure the large-scale intrinsic alignments of galaxy clusters in the
Sloan Digital Sky Survey (SDSS) using subsets of two cluster catalogues: 6625
clusters with 0.1<z<0.3 from the maxBCG cluster catalogue (Koester et al. 2007,
7500 sq. deg.), and 8081 clusters with 0.08<z<0.44 from the Adaptive Matched
Filter catalogue (Dong et al. 2008, 6500 sq. deg.). We search for two types of
cluster alignments using pairs of clusters: the alignment between the projected
major axes of the clusters (`correlation' alignment), and the alignment between
one cluster major axis and the line connecting it to the other cluster in the
pair (`pointing' alignment). In each case, we use the cluster member galaxy
distribution as a tracer of the cluster shape. All measurements are carried out
with each catalogue separately, to check for dependence on cluster selection
procedure. We find a strong detection of the pointing alignment on scales up to
100 Mpc/h, at the 6 or 10-sigma level depending on the cluster selection
algorithm used. The correlation alignment is only marginally detected up to ~20
Mpc/h, at the 2 or 2.5-sigma level. These results support our current
theoretical understanding of galaxy cluster intrinsic alignments in the LCDM
paradigm, although further work will be needed to understand the impact of
cluster selection effects and observational measurement errors on the amplitude
of the detection.Comment: 6 pages, 2 figures, submitted to MNRAS; minor revisions to address
referee comments primarily in section 5, no changes to result
Sensor Fusion of Structure-from-Motion, Bathymetric 3D, and Beacon-Based Navigation Modalities
This paper describes an approach for the fusion of 30
data underwater obtained from multiple sensing modalities.
In particular, we examine the combination of imagebased
Structure-From-Motion (SFM) data with bathymetric
data obtained using pencil-beam underwater sonar, in
order to recover the shape of the seabed terrain. We also
combine image-based egomotion estimation with acousticbased
and inertial navigation data on board the underwater
vehicle.
We examine multiple types of fusion. When fusion is
pe?$ormed at the data level, each modality is used to extract
30 information independently. The 30 representations
are then aligned and compared. In this case, we use
the bathymetric data as ground truth to measure the accuracy
and drijl of the SFM approach. Similarly we use
the navigation data as ground truth against which we measure
the accuracy of the image-based ego-motion estimation.
To our knowledge, this is the frst quantitative evaluation
of image-based SFM and egomotion accuracy in a
large-scale outdoor environment.
Fusion at the signal level uses the raw signals from multiple
sensors to produce a single coherent 30 representation
which takes optimal advantage of the sensors' complementary
strengths. In this papel; we examine how lowresolution
bathymetric data can be used to seed the higherresolution
SFM algorithm, improving convergence rates,
and reducing drift error. Similarly, acoustic-based and inertial
navigation data improves the convergence and driji
properties of egomotion estimation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86044/1/hsingh-35.pd
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