1,018 research outputs found
Data assimilation and the adjoint method: an example
May 1991.Includes bibliographical references.The following are copies of slides of a talk presenting a method of four dimensional data assimilation based on the adjoint method via considering a simple example.Research supported by U.S. Army Research Office under Grant no. DAAL 03-86-K-0175
Data assimilation and the adjoint method: an overview
May 1991.Includes bibliographical references.In this note a general description of the application of the adjoint method for four dimensional data assimilation is given. The main focus of this discussion is that this method when applied to a discrete model is simply an application of the chair rule of multivariate calculus to compute the gradient of a real valued function of several variables. Several different time differencing schemes are considered, as well as, two examples of discrete models.Research supported by U.S. Army Research Office under Grant no. DAAL 03-86-K-0175
Pliocene Molluscs and Fishes from Northeastern California and Northwestern Nevada
339-413http://deepblue.lib.umich.edu/bitstream/2027.42/48508/2/ID359.pd
Exact Numerical Solution of the BCS Pairing Problem
We propose a new simulation computational method to solve the reduced BCS
Hamiltonian based on spin analogy and submatrix diagonalization. Then we
further apply this method to solve superconducting energy gap and the results
are well consistent with those obtained by Bogoliubov transformation method.
The exponential problem of 2^{N}-dimension matrix is reduced to the polynomial
problem of N-dimension matrix. It is essential to validate this method on a
real quantumComment: 7 pages, 3 figure
An integrated genomic analysis of lung cancer reveals loss of DUSP4 in EGFR-mutant tumors.
To address the biological heterogeneity of lung cancer, we studied 199 lung adenocarcinomas by integrating genome-wide data on copy number alterations and gene expression with full annotation for major known somatic mutations in this cancer. This showed non-random patterns of copy number alterations significantly linked to EGFR and KRAS mutation status and to distinct clinical outcomes, and led to the discovery of a striking association of EGFR mutations with underexpression of DUSP4, a gene within a broad region of frequent single-copy loss on 8p. DUSP4 is involved in negative feedback control of EGFR signaling, and we provide functional validation for its role as a growth suppressor in EGFR-mutant lung adenocarcinoma. DUSP4 loss also associates with p16/CDKN2A deletion and defines a distinct clinical subset of lung cancer patients. Another novel observation is that of a reciprocal relationship between EGFR and LKB1 mutations. These results highlight the power of integrated genomics to identify candidate driver genes within recurrent broad regions of copy number alteration and to delineate distinct oncogenetic pathways in genetically complex common epithelial cancers
Simplified Vacuum Energy Expressions for Radial Backgrounds and Domain Walls
We extend our previous results of simplified expressions for functional
determinants for radial Schr\"odinger operators to the computation of vacuum
energy, or mass corrections, for static but spatially radial backgrounds, and
for domain wall configurations. Our method is based on the zeta function
approach to the Gel'fand-Yaglom theorem, suitably extended to higher
dimensional systems on separable manifolds. We find new expressions that are
easy to implement numerically, for both zero and nonzero temperature.Comment: 30 page
An analysis of identical single-nucleotide polymorphisms genotyped by two different platforms
The overlap of 94 single-nucleotide polymorphisms (SNP) among the 4,720 and 11,120 SNPs contained in the linkage panels of Illumina and Affymetrix, respectively, allows an assessment of the discrepancy rate produced by these two platforms. Although the no-call rate for the Affymetrix platform is approximately 8.6 times greater than for the Illumina platform, when both platforms make a genotypic call, the agreement is an impressive 99.85%. To determine if disputed genotypes can be resolved without sequencing, we studied recombination in the region of the discrepancy for the most discrepant SNP rs958883 (typed by Illumina) and tsc02060848 (typed by Affymetrix). We find that the number of inferred recombinants is substantially higher for the Affymetrix genotypes compared to the Illumina genotypes. We illustrate this with pedigree 10043, in which 3 of 7 versus 0 of 7 offspring must be double recombinants using the genotypes from the Affymetrix and the Illumina platforms, respectively. Of the 36 SNPs with one or more discrepancies, we identified a subset that appears to cluster in families. Some of this clustering may be due to the presence of a second segregating SNP that obliterates a XbaI site (the restriction enzyme used in the Affymetrix platform), resulting in a fragment too long (>1,000 bp) to be amplified
Galactic-Scale Outflow and Supersonic Ram-Pressure Stripping in the Virgo Cluster Galaxy NGC 4388
The Hawaii Imaging Fabry-Perot Interferometer (HIFI) on the University of
Hawaii 2.2m telescope was used to map the Halpha and [O III] 5007 A
emission-line profiles across the entire disk of the edge-on Sb galaxy NGC
4388. We confirm a rich complex of highly ionized gas that extends ~4 kpc above
the disk of this galaxy. Low-ionization gas associated with star formation is
also present in the disk. Evidence for bar streaming is detected in the disk
component and is discussed in a companion paper (Veilleux, Bland-Hawthorn, &
Cecil 1999; hereafter VBC). Non-rotational blueshifted velocities of 50 - 250
km/s are measured in the extraplanar gas north-east of the nucleus. The
brighter features in this complex tend to have more blueshifted velocities. A
redshifted cloud is also detected 2 kpc south-west of the nucleus. The velocity
field of the extraplanar gas of NGC 4388 appears to be unaffected by the
inferred supersonic (Mach number M ~ 3) motion of this galaxy through the ICM
of the Virgo cluster. We argue that this is because the galaxy and the high-|z|
gas lie behind a Mach cone with opening angle ~ 80 degrees. The shocked ICM
that flows near the galaxy has a velocity of ~ 500 km/s and exerts insufficient
ram pressure on the extraplanar gas to perturb its kinematics. We consider
several explanations of the velocity field of the extraplanar gas. Velocities,
especially blueshifted velocities on the N side of the galaxy, are best
explained as a bipolar outflow which is tilted by > 12 degrees from the normal
to the disk. The observed offset between the extraplanar gas and the radio
structure may be due to buoyancy or refractive bending by density gradients in
the halo gas. Velocity substructure in the outflowing gas also suggests an
interaction with ambient halo gas.Comment: 29 pages including 5 figures, Latex, requires aaspp4.sty, to appear
in ApJ, 520 (July 20, 1999 issue
Early Change in Urine Protein as a Surrogate End Point in Studies of IgA Nephropathy: An Individual-Patient Meta-analysis
Background The role of change in proteinuria as a surrogate end point for randomized trials in immunoglobulin A nephropathy (IgAN) has previously not been thoroughly evaluated. Study Design Individual patientâlevel meta-analysis. Setting & Population Individual-patient data for 830 patients from 11 randomized trials evaluating 4 intervention types (renin-angiotensin system [RAS] blockade, fish oil, immunosuppression, and steroids) examining associations between changes in urine protein and clinical end points at the individual and trial levels. Selection Criteria for Studies Randomized controlled trials of IgAN with measurements of proteinuria at baseline and a median of 9 (range, 5-12) months follow-up, with at least 1 further year of follow-up for the clinical outcome. Predictor 9-month change in proteinuria. Outcome Doubling of serum creatinine level, end-stage renal disease, or death. Results Early decline in proteinuria at 9 months was associated with lower risk for the clinical outcome (HR per 50% reduction in proteinuria, 0.40; 95% CI, 0.32-0.48) and was consistent across studies. Proportions of treatment effect on the clinical outcome explained by early decline in proteinuria were estimated at 11% (95% CI, â19% to 41%) for RAS blockade and 29% (95% CI, 6% to 53%) for steroid therapy. The direction of the pooled treatment effect on early change in proteinuria was in accord with the direction of the treatment effect on the clinical outcome for steroids and RAS blockade. Trial-level analyses estimated that the slope for the regression line for the association of treatment effects on the clinical end points and for the treatment effect on proteinuria was 2.15 (95% Bayesian credible interval, 0.10-4.32). Limitations Study population restricted to 11 trials, all having fewer than 200 patients each with a limited number of clinical events. Conclusions Results of this analysis offer novel evidence supporting the use of an early reduction in proteinuria as a surrogate end point for clinical end points in IgAN in selected settings
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
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