3,046 research outputs found
Covariance analysis of the airborne laser ranging system
The requirements and limitations of employing an airborne laser ranging system for detecting crustal shifts of the Earth within centimeters over a region of approximately 200 by 400 km are presented. The system consists of an aircraft which flies over a grid of ground deployed retroreflectors, making six passes over the grid at two different altitudes. The retroreflector baseline errors are assumed to result from measurement noise, a priori errors on the aircraft and retroreflector positions, tropospheric refraction, and sensor biases
Stochastic density functional theory
Linear-scaling implementations of density functional theory (DFT) reach their
intended efficiency regime only when applied to systems having a physical size
larger than the range of their Kohn-Sham density matrix (DM). This causes a
problem since many types of large systems of interest have a rather broad DM
range and are therefore not amenable to analysis using DFT methods. For this
reason, the recently proposed stochastic DFT (sDFT), avoiding exhaustive DM
evaluations, is emerging as an attractive alternative linear-scaling approach.
This review develops a general formulation of sDFT in terms of a
(non)orthogonal basis representation and offers an analysis of the statistical
errors (SEs) involved in the calculation. Using a new Gaussian-type basis-set
implementation of sDFT, applied to water clusters and silicon nanocrystals, it
demonstrates and explains how the standard deviation and the bias depend on the
sampling rate and the system size in various types of calculations. We also
develop basis-set embedded-fragments theory, demonstrating its utility for
reducing the SEs for energy, density of states and nuclear force calculations.
Finally, we discuss the algorithmic complexity of sDFT, showing it has CPU
wall-time linear-scaling. The method parallelizes well over distributed
processors with good scalability and therefore may find use in the upcoming
exascale computing architectures
Information-theoretic determination of ponderomotive forces
From the equilibrium condition applied to an isolated
thermodynamic system of electrically charged particles and the fundamental
equation of thermodynamics () subject
to a new procedure, it is obtained the Lorentz's force together with
non-inertial terms of mechanical nature. Other well known ponderomotive forces,
like the Stern-Gerlach's force and a force term related to the Einstein-de
Haas's effect are also obtained. In addition, a new force term appears,
possibly related to a change in weight when a system of charged particles is
accelerated.Comment: 10 page
Умови розвитку методологічної культури майбутнього вчителя у педагогіці Василя Сухомлинського
У статті висвітлюються теоретичні засади та методичні аспекти розвитку методологічної культури майбутнього вчителя у педагогічній спадщині Василя Сухомлинського. Автор акцентує увагу на дослідженні інтерпертації видатним педагогом змісту та умов формування методологічної культури як важливої характеристики професіоналізму вчителя
Ocean warming, not acidification, controlled coccolithophore response during past greenhouse climate change
Current carbon dioxide emissions are an assumed threat to oceanic calcifying plankton
(coccolithophores) not just due to rising sea-surface temperatures, but also because of ocean
acidification (OA). This assessment is based on single species culture experiments that are now
revealing complex, synergistic, and adaptive responses to such environmental change. Despite
this complexity, there is still a widespread perception that coccolithophore calcification will
be inhibited by OA. These plankton have an excellent fossil record, and so we can test for the
impact of OA during geological carbon cycle events, providing the added advantages of exploring
entire communities across real-world major climate perturbation and recovery. Here
we target fossil coccolithophore groups (holococcoliths and braarudosphaerids) expected to
exhibit greatest sensitivity to acidification because of their reliance on extracellular calcification.
Across the Paleocene-Eocene Thermal Maximum (56 Ma) rapid warming event, the biogeography
and abundance of these extracellular calcifiers shifted dramatically, disappearing
entirely from low latitudes to become limited to cooler, lower saturation-state areas. By comparing
these range shift data with the environmental parameters from an Earth system model,
we show that the principal control on these range retractions was temperature, with survival
maintained in high-latitude refugia, despite more adverse ocean chemistry conditions. Deleterious
effects of OA were only evidenced when twinned with elevated temperatures
Notes upon trees and shrubs adapted to central Illinois : with especial reference to their value in ornamental planting
Thesis (B.S)--University of Illinois, 1900.Typescript.Includes bibliographical references
Degenerate distributions in complex Langevin dynamics: one-dimensional QCD at finite chemical potential
We demonstrate analytically that complex Langevin dynamics can solve the sign
problem in one-dimensional QCD in the thermodynamic limit. In particular, it is
shown that the contributions from the complex and highly oscillating spectral
density of the Dirac operator to the chiral condensate are taken into account
correctly. We find an infinite number of classical fixed points of the Langevin
flow in the thermodynamic limit. The correct solution originates from a
continuum of degenerate distributions in the complexified space.Comment: 20 pages, several eps figures, minor comments added, to appear in
JHE
Compensatory Blood-Brotherhood: A Comparative Analysis of Institutionalized Friendship in Two African Societies
- …
