4,936 research outputs found
Relative entropy as a measure of inhomogeneity in general relativity
We introduce the notion of relative volume entropy for two spacetimes with
preferred compact spacelike foliations. This is accomplished by applying the
notion of Kullback-Leibler divergence to the volume elements induced on
spacelike slices. The resulting quantity gives a lower bound on the number of
bits which are necessary to describe one metric given the other. For
illustration, we study some examples, in particular gravitational waves, and
conclude that the relative volume entropy is a suitable device for quantitative
comparison of the inhomogeneity of two spacetimes.Comment: 15 pages, 7 figure
On the coexistence of position and momentum observables
We investigate the problem of coexistence of position and momentum
observables. We characterize those pairs of position and momentum observables
which have a joint observable
Note and Comment
Special Assessments Upon Cemetaries - Though the power to tax cemeteries would seem to be\u27entirely clear, very commonly land devoted to such purpose is declared by constitution or statute to be exempt. See CooLY, TAxATION, (3rd ed.) 354. So also in the case of special assessments such land, in the absence of a clear exemption, is liable thereto. Bloomington Cemetery Assoc. v. People, i39 IIl. 16, 28 N. E. io76; Mullins v. Cemetery Assoc., 239 Mo. 681, i44 S. W. iog; Buffalo City Cemetery v. Buffalo, 46 N. Y. 5o3; Lima v. Lima Cemetery Assoc., 42 Oh. St. 128, 5! Am. Rep. 8ag. It may be suggested, in view of the theory upon which special assessments go; that the owner of the land gets back the amount assessed in benefits from an enhanced value of the property, land dedicated to cemetery purposes perpetually would not be subject to such assessments. This contention wa urged in Garden Cemetery Corporation v. Baker, 218 Mass. 339, 105 N. E. io7o (x9r4), and under the facts there presented was rejected, the court distinguishing Mount Auburn Cemetery v. Cambridge, i5o Mass. 12. Where all the lots are sold and used for burial and under the law the company cannot divert the land to other uses, perhaps the argument might be difficult to meet. Exemption from special assessment, then, in general, it would seem, must be found, if at all, in some provision or provisions of the conititution, statutes, or charter, or in some inherent difficulty in the collection of the assessments
Environment and Obesity in the National Children\u27s Study
Objective: In this review we describe the approach taken by the National Children’s Study (NCS), a 21-year prospective study of 100,000 American children, to understanding the role of environmental factors in the development of obesity.
Data sources and extraction: We review the literature with regard to the two core hypotheses in the NCS that relate to environmental origins of obesity and describe strategies that will be used to test each hypothesis.
Data synthesis: Although it is clear that obesity in an individual results from an imbalance between energy intake and expenditure, control of the obesity epidemic will require understanding of factors in the modern built environment and chemical exposures that may have the capacity to disrupt the link between energy intake and expenditure. The NCS is the largest prospective birth cohort study ever undertaken in the United States that is explicitly designed to seek information on the environmental causes of pediatric disease.
Conclusions: Through its embrace of the life-course approach to epidemiology, the NCS will be able to study the origins of obesity from preconception through late adolescence, including factors ranging from genetic inheritance to individual behaviors to the social, built, and natural environment and chemical exposures. It will have sufficient statistical power to examine interactions among these multiple influences, including gene–environment and gene–obesity interactions. A major secondary benefit will derive from the banking of specimens for future analysis
Rotary atomizer drop size distribution database
Wind tunnel measurements of drop Size distributions from Micronair A U4000 and A U5000 rotary atomizers were collected to develop a database for model use. The measurements varied tank mix, flow rate, air speed, and blade angle conditions, which were correlated by multiple regressions (average R-2 = 0.995 for A U4000 and 0.988 for AU5000). This database replaces an outdated set of rotary atomizer data measured in the 1980s by the USDA Forest Service and fills in a gap in data measured in the 1990s by the Spray Drift Task Force. Since current USDA Forest Service spray projects rely on rotary atomizers, the creation of the database (and its multiple regression interpolation) satisfies a need seen for ten years
Characterization of the Response of Primary Cells Relevant to Dialysis-Related Amyloidosis to β2-Microglobulin Monomer and Fibrils
The formation of insoluble amyloid fibrils is associated with an array of devastating human diseases. Dialysis-related amyloidosis (DRA) is a severe complication of hemodialysis that results in the progressive destruction of the bones and joints. Elevated concentrations of β2-microglobulin (β2m) in the serum of subjects on hemodialysis promote the formation of amyloid fibrils in the osteoarticular tissues, but the cellular basis for the destruction of these tissues in DRA is poorly understood. In this study we performed a systematic analysis of the interaction of monomeric and fibrillar β2m with primary human cells of the types present in the synovial joints of subjects with DRA. Building upon observations that macrophages infiltrate β2m amyloid deposits in vivo we demonstrate that monocytes, the precursors of macrophages, cannot degrade β2m fibrils, and that both monomeric β2m and fibrillar β2m are cytotoxic to these cells. β2m fibrils also impair the formation of bone resorbing osteoclasts from monocytes and reduce the viability of osteoblasts, the cell type that produces bone. As a consequence, we predict that β2m amyloid will disrupt the remodelling of the bone, which is critical for the maintenance of this tissue. Moreover, we show that β2m fibrils reduce the viability of chondrocytes, rationalizing the loss of cartilage in DRA. Together, our observations demonstrate that β2m cytotoxicity has multiple cellular targets in the osteoarticular tissues and is likely to be a key factor in the bone and joint destruction characteristic of DRA
Decoherence produces coherent states: an explicit proof for harmonic chains
We study the behavior of infinite systems of coupled harmonic oscillators as
t->infinity, and generalize the Central Limit Theorem (CLT) to show that their
reduced Wigner distributions become Gaussian under quite general conditions.
This shows that generalized coherent states tend to be produced naturally. A
sufficient condition for this to happen is shown to be that the spectral
function is analytic and nonlinear. For a rectangular lattice of coupled
oscillators, the nonlinearity requirement means that waves must be dispersive,
so that localized wave-packets become suppressed. Virtually all harmonic
heat-bath models in the literature satisfy this constraint, and we have good
reason to believe that coherent states and their generalizations are not merely
a useful analytical tool, but that nature is indeed full of them. Standard
proofs of the CLT rely heavily on the fact that probability densities are
non-negative. Although the CLT generally fails if the probability densities are
allowed to take negative values, we show that a CLT does indeed hold for a
special class of such functions. We find that, intriguingly, nature has
arranged things so that all Wigner functions belong to this class.Comment: Final published version. 17 pages, Plain TeX, no figures. Online at
http://astro.berkeley.edu/~max/gaussians.html (faster from the US), from
http://www.mpa-garching.mpg.de/~max/gaussians.html (faster from Europe) or
from [email protected]
Association of eNOS polymorphisms with primary angle-closure glaucoma
Author version made available in accordance with the publisher's policy.Purpose: Recently, several studies have investigated genetic associations between Cytochrome P450 (CYP1B1), Endothelial nitric oxide synthase (eNOS) and Neurotrophin-4 (NTF4) with primary angle-closure glaucoma (PACG) in various ethnic groups. Here we investigate the association of these candidate genes with PACG in samples from Australia and Nepal.
Method: A total of 235 patients with PACG (106 Nepalese and 129 Australian) and 492 controls (204 Nepalese and 288 Australian) were included. Tag single nucleotide polymorphisms (SNPs) were selected to cover the majority of common variation within the candidate genes and genotyped in DNA extracted from peripheral whole blood. Allele and haplotype analyses were conducted in PLINK. Bonferroni correction was applied for the total number of SNPs in this study (p=0.05/15=0.003)
Results: In the Australian cohort, one eNOS SNP rs3793342 shows significance association with PACG in the Australian cohort after Bonferroni correction (p-value 0.003, OR 0.5 95% CI 0.3-0.8). After adjusting the results for sex and age both SNPs rs3793342 and rs7830 showed significance after Bonferroni correction (p-value of 0.001 and 0.003, respectively). The eNOS haplotype of all 7 typed SNPs showed significant association with a global p-value of 0.019, with the CGCAATC haplotype giving a specific p-value of 0.008 and odds ratio of 1.5 (95% CI 0.9-2.4). In the Nepalese cohort, SNPs in CYP1B1 and NTF4 genes showed borderline association with PACG but did not survive Bonferroni correction.
Conclusions: The present data support the involvement of common variations in eNOS with PACG pathogenesis. Differences were observed in the two populations studied, and additional replication studies in other populations are necessary to confirm these association
A cross-ethnicity investigation of genes previously implicated in primary angle closure glaucoma
Purpose: To investigate the underlying genetic variation between candidate genes and primary angle closure glaucoma
(PACG) in both Nepalese and Australian populations.
Methods: A total of 213 patients with PACG (106 Nepalese and 107 Australian) and 492 age and sex matched controls
(204 Nepalese and 288 Australian) were included in the current study. Three candidate genes were selected; methyltetrahydrofolate
reductase (MTHFR), calcitonin receptor-like receptor gene (CALCRL), and membrane frizzled-related
protein (MFRP). Tag single nucleotide polymorphisms (SNPs) were selected and genotyped to capture the majority of
common variation across each locus. Allele and haplotype analyses were conducted using PLINK.
Results: SNPs in the nanophthalmos gene MFRP were found to be nominally associated with PACG under the allelic
model. Two SNPs were associated in the Australian cohort (rs948414; p=0.02 and rs36015759; p=0.02), and a single SNP
in the Nepalese cohort (rs10790289; p=0.03), however these SNPs failed to remain significant after adjustment for sex
and age. A haplotype at the CALCRL gene (AATACAGAT) was associated in the Australian cohort (corrected p-value=
0.024). No association was observed in either cohort for MTHFR.
Conclusions: This study implicates genetic variation at the CALCRL gene in the pathogenesis of PACG in an Australian
Caucasian cohort. Additionally, the MFRP gene shows tendency to be associated with PACG in both the Australian and
Nepalese cohorts. Further investigation in a larger cohort is warranted to confirm these findings. No statistically significant
associations were identified between MTHFR and PACG in either population
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