146,924 research outputs found
TumorML: Concept and requirements of an in silico cancer modelling markup language
This paper describes the initial groundwork carried out as part of the European Commission funded Transatlantic Tumor Model Repositories project, to develop a new markup language for computational cancer modelling, TumorML. In this paper we describe the motivations for such a language, arguing that current state-of-the-art biomodelling languages are not suited to the cancer modelling domain. We go on to describe the work that needs to be done to develop TumorML, the conceptual design, and a description of what existing markup languages will be used to compose the language specification
Cold cathode gauge experiment (ALSEP)
Cold cathode ionization gages were left on the lunar surface as part of ALSEP (Apollo Lunar Surface Experiment Package) on Apollo missions 12, 14, and 15. An instrument prepared for Apollo 13 did not reach the surface because of the abort of that mission. The gages that reached the lunar surface measured the amounts of gas present in the vicinity of the ALSEP sites. The observed daytime gas concentrations were initially about two orders of magnitude greater than the nighttime observations; this was due to contamination of the landing area by the Apollo operations and equipment, and the daytime measurements showed a decrease with time characterized by a time constant of a few months
Interpretation at the controller's edge: designing graphical user interfaces for the digital publication of the excavations at Gabii (Italy)
This paper discusses the authors’ approach to designing an interface for the Gabii Project’s digital volumes that attempts to fuse elements of traditional synthetic publications and site reports with rich digital datasets. Archaeology, and classical archaeology in particular, has long engaged with questions of the formation and lived experience of towns and cities. Such studies might draw on evidence of local topography, the arrangement of the built environment, and the placement of architectural details, monuments and inscriptions (e.g. Johnson and Millett 2012). Fundamental to the continued development of these studies is the growing body of evidence emerging from new excavations. Digital techniques for recording evidence “on the ground,” notably SFM (structure from motion aka close range photogrammetry) for the creation of detailed 3D models and for scene-level modeling in 3D have advanced rapidly in recent years. These parallel developments have opened the door for approaches to the study of the creation and experience of urban space driven by a combination of scene-level reconstruction models (van Roode et al. 2012, Paliou et al. 2011, Paliou 2013) explicitly combined with detailed SFM or scanning based 3D models representing stratigraphic evidence. It is essential to understand the subtle but crucial impact of the design of the user interface on the interpretation of these models. In this paper we focus on the impact of design choices for the user interface, and make connections between design choices and the broader discourse in archaeological theory surrounding the practice of the creation and consumption of archaeological knowledge. As a case in point we take the prototype interface being developed within the Gabii Project for the publication of the Tincu House. In discussing our own evolving practices in engagement with the archaeological record created at Gabii, we highlight some of the challenges of undertaking theoretically-situated user interface design, and their implications for the publication and study of archaeological materials
Low-energy, planar magnetic defects in BaFe2As2: nanotwins, twins, antiphase and domain boundaries
In BaFe2As2, structural and magnetic planar defects begin to proliferate
below the structural phase transition, affecting descriptions of magnetism and
superconductivity. We study using density-functional theory the stability and
magnetic properties of competing antiphase and domain boundaries, twins and
isolated twins (twin nuclei) - spin excitations proposed and/or observed.
These nanoscale defects have very low surface energy (-~Jm),
with twins favorable to the mesoscale. Defects exhibit smaller moments confined
near their boundaries -- making a uniform-moment picture inappropriate for
long-range magnetic order in real samples. {\it{Nano}}twins explain features in
measured pair distribution functions, so should be considered when analyzing
scattering data. All these defects can be weakly mobile and/or have
fluctuations that lower assessed "ordered" moments from longer spatial and/or
time averaging, and should be considered directly.Comment: 6 pages, 6 figures, 1 tabl
Near-wall, three-dimensional turbulence measurements: A challenge for laser velocimetry
A new laser velocimeter approach is presented, which has distinct advantages in near-wall, two- and three-dimensional turbulence measurement applications. The approach does require placing a probe into the flow; but in return, there are some important benefits, such as, the direct measurement of the crossflow velocity, w, at a grazing incidence, and the ability to size optical components for the scale of the flow rather than the size of the facility. Promising resuls were obtained with this approach for a two-dimensional turbulent boundary layer
Haldane fractional statistics in the fractional quantum Hall effect
We have tested Haldane's ``fractional-Pauli-principle'' description of
excitations around the state in the FQHE, using exact results for
small systems of electrons. We find that Haldane's prediction
for quasiholes and quasiparticles, respectively, describes our results well
with the modification rather than . We also find
that this approach enables us to better understand the {\it energetics\/} of
the ``daughter'' states; in particular, we find good evidence, in terms of the
effective interaction between quasiparticles, that the states and
4/13 should not be stable.Comment: 9 pages, 3 Postscript figures, RevTex 3.0. (UCF-CM-93-005
Testing equality of variances in the analysis of repeated measurements
The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.\ud
\ud
The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies
Computer code to interchange CDS and wave-drag geometry formats
A computer program has been developed on the PRIME minicomputer to provide an interface for the passage of aircraft configuration geometry data between the Rockwell Configuration Development System (CDS) and a wireframe geometry format used by aerodynamic design and analysis codes. The interface program allows aircraft geometry which has been developed in CDS to be directly converted to the wireframe geometry format for analysis. Geometry which has been modified in the analysis codes can be transformed back to a CDS geometry file and examined for physical viability. Previously created wireframe geometry files may also be converted into CDS geometry files. The program provides a useful link between a geometry creation and manipulation code and analysis codes by providing rapid and accurate geometry conversion
What is a quantum simulator?
Quantum simulators are devices that actively use quantum effects to answer
questions about model systems and, through them, real systems. Here we expand
on this definition by answering several fundamental questions about the nature
and use of quantum simulators. Our answers address two important areas. First,
the difference between an operation termed simulation and another termed
computation. This distinction is related to the purpose of an operation, as
well as our confidence in and expectation of its accuracy. Second, the
threshold between quantum and classical simulations. Throughout, we provide a
perspective on the achievements and directions of the field of quantum
simulation.Comment: 13 pages, 2 figure
- …