378 research outputs found
Molecular and clinical pharmacology of psoriasis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136054/1/cpt1974165part2919.pd
Perturbation expansions for a class of singular potentials
Harrell's modified perturbation theory [Ann. Phys. 105, 379-406 (1977)] is
applied and extended to obtain non-power perturbation expansions for a class of
singular Hamiltonians H = -D^2 + x^2 + A/x^2 + lambda/x^alpha, (A\geq 0, alpha
> 2), known as generalized spiked harmonic oscillators. The perturbation
expansions developed here are valid for small values of the coupling lambda >
0, and they extend the results which Harrell obtained for the spiked harmonic
oscillator A = 0. Formulas for the the excited-states are also developed.Comment: 23 page
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Containerization on Petascale HPC Clusters
Containerization technologies provide a mechanism to encapsulate applications and many of their dependencies, facilitating software portability and reproducibility on HPC systems. However, in order to access many of the architectural features that enable HPC system performance, compatibility between certain components of the container and host are required, resulting in a trade-off between portability and performance. In this work, we discuss our early experiences running three state-of-the-art containerization technologies on the petascale Frontera system. We present how we build the containers to ensure performance and security and their performance at scale.We ran microbenchmarks at a scale of 4,096 nodes and demonstrate the near-native performance and minimal memory overheads by the containerized environments at 70,000 processes on 1,296 nodes with a scientific application MILC - a quantum chromodynamics code.UT Austin-Portugal Program, a collaboration between the Portuguese Foundation of Science and Technology and the University of Texas at Austin, award UTA18-001217Texas Advanced Computing Center (TACC
The impact of adolescent exposure to medical marijuana laws on high school completion, college enrollment and college degree completion
Background: There is concern that medical marijuana laws (MMLs) could negatively affect adolescents. To better understand these policies, we assess how adolescent exposure to MMLs is related to educational attainment. Methods: Data from the 2000 Census and 2001-2014 American Community Surveys were restricted to individuals who were of high school age (14-18) between 1990 and 2012 (n = 5,483,715). MML exposure was coded as: (i) a dichotomous any MML indicator, and (ii) number of years of high school age exposure. We used logistic regression to model whether MMLs affected: (a) completing high school by age 19; (b) beginning college, irrespective of completion; and (c) obtaining any degree after beginning college. A similar dataset based on the Youth Risk Behavior Survey (YRBS) was also constructed for confirmatory analyses assessing marijuana use. Results: MMLs were associated with a 0.40 percentage point increase in the probability of not earning a high school diploma or GED after completing the 12th grade (from 3.99% to 4.39%). High school MML exposure was also associated with a 1.84 and 0.85 percentage point increase in the probability of college non-enrollment and degree non-completion, respectively (from 31.12% to 32.96% and 45.30% to 46.15%, respectively). Years of MML exposure exhibited a consistent dose response relationship for all outcomes. MMLs were also associated with 0.85 percentage point increase in daily marijuana use among 12th graders (up from 1.26%). Conclusions: Medical marijuana law exposure between age 14 to 18 likely has a delayed effect on use and education that persists over time. (C) 2016 Elsevier Ireland Ltd. All rights reserved
Variational analysis for a generalized spiked harmonic oscillator
A variational analysis is presented for the generalized spiked harmonic
oscillator Hamiltonian operator H, where H = -(d/dx)^2 + Bx^2+ A/x^2 +
lambda/x^alpha, and alpha and lambda are real positive parameters. The
formalism makes use of a basis provided by exact solutions of Schroedinger's
equation for the Gol'dman and Krivchenkov Hamiltonian (alpha = 2), and the
corresponding matrix elements that were previously found. For all the discrete
eigenvalues the method provides bounds which improve as the dimension of the
basis set is increased. Extension to the N-dimensional case in arbitrary
angular-momentum subspaces is also presented. By minimizing over the free
parameter A, we are able to reduce substantially the number of basis functions
needed for a given accuracy.Comment: 15 pages, 1 figur
PADLL: Taming Metadata-intensive HPC Jobs Through Dynamic, Application-agnostic QoS Control
Modern I/O applications that run on HPC infrastructures are increasingly
becoming read and metadata intensive. However, having multiple concurrent
applications submitting large amounts of metadata operations can easily
saturate the shared parallel file system's metadata resources, leading to
overall performance degradation and I/O unfairness. We present PADLL, an
application and file system agnostic storage middleware that enables QoS
control of data and metadata workflows in HPC storage systems. It adopts ideas
from Software-Defined Storage, building data plane stages that mediate and rate
limit POSIX requests submitted to the shared file system, and a control plane
that holistically coordinates how all I/O workflows are handled. We demonstrate
its performance and feasibility under multiple QoS policies using synthetic
benchmarks, real-world applications, and traces collected from a production
file system. Results show that PADLL can enforce complex storage QoS policies
over concurrent metadata-aggressive jobs, ensuring fairness and prioritization.Comment: To appear at 23rd IEEE/ACM International Symposium on Cluster, Cloud
and Internet Computing (CCGrid'23
Sums of magnetic eigenvalues are maximal on rotationally symmetric domains
The sum of the first n energy levels of the planar Laplacian with constant
magnetic field of given total flux is shown to be maximal among triangles for
the equilateral triangle, under normalization of the ratio (moment of
inertia)/(area)^3 on the domain. The result holds for both Dirichlet and
Neumann boundary conditions, with an analogue for Robin (or de Gennes) boundary
conditions too. The square similarly maximizes the eigenvalue sum among
parallelograms, and the disk maximizes among ellipses. More generally, a domain
with rotational symmetry will maximize the magnetic eigenvalue sum among all
linear images of that domain. These results are new even for the ground state
energy (n=1).Comment: 19 pages, 1 figur
Asymptotic iteration method for eigenvalue problems
An asymptotic interation method for solving second-order homogeneous linear
differential equations of the form y'' = lambda(x) y' + s(x) y is introduced,
where lambda(x) \neq 0 and s(x) are C-infinity functions. Applications to
Schroedinger type problems, including some with highly singular potentials, are
presented.Comment: 14 page
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Neuropsychological Test Performance in African-American and White Patients with Alzheimer's Disease
Little information exists on the performance of black versus white patients with Alzheimer's disease on neuropsychological tests for dementia.In this study, we compared performance on the CERAD (Consortium to Establish a Registry for Alzheimer's Disease) neuropsychological battery between white (n equals 830) and black (n equals 158) patients with Alzheimer's disease enrolled in the CERAD study at 23 university medical centers in the United States. The black patients were older, had fewer years of formal education, and were more impaired in their activities of daily living than were the white patients. After controlling for these characteristics and for duration of the disease and severity of dementia, there were differences in the performance of black and white patients on several of the cognitive measures. Black patients scored lower than whites on tests of visual naming and constructional praxis and on the Mini-Mental State Examination. There were no statistical differences in performance on tests of fluency and word list memory. These findings suggest that cultural or experiential differences may modify performance on specific neuropsychological tests. These factors, in addition to age and educational background, should be considered when interpreting performance on neuropsychological tests in elderly black patients with dementia
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