256 research outputs found
Terrain Sculptor: generalizing terrain models for relief shading
Shaded relief derived from high-resolution terrain models often contains distracting terrain details that need to be removed for medium- and small- scale mapping. When standard raster filter operations are applied to digital terrain data, important ridge tops and valley edges are blurred, altering the characteristic shape of these features in the resulting shaded relief. This paper introduces Terrain Sculptor, a software application that prepares generalized terrain models for relief shading. The application uses a generalization methodology based on a succession of raster operations. Curvature coefficients detect and accentuate important relief features. Terrain Sculptor offers a graphical user interface to adjust the algorithm to various scales and terrain resolutions
Metabolic effects of a mixed and a high-carbohydrate low-fat diet in man, measured over 24 h in a respiration chamber
1. The relation between dietary carbohydrate:lipid ratio and the fuel mixture oxidized during 24 h was investigated in eleven healthy volunteers (six females, and five males) in a respiration chamber. Values of the fuel mixture oxidized were estimated by continuous indirect calorimetry and urinary nitrogen measurements. 2. The subjects were first given a mixed diet for 7 d and spent the last 24 h of the 7 d period in a respiration chamber for continuous gas-exchange measurement. The fuels oxidized during 2·5 h of moderate exercise were also measured in the respiration chamber. After an interval of 2 weeks from the end of the mixed-diet period, the same subjects were given an isoenergetic high-carbohydrate low-fat diet for 7 d, and the same experimental regimen was repeated. 3. Dietary composition markedly influenced the fuel mixture oxidized during 24 h and this effect was still present 12 h after the last meal in the postabsorptive state. However, the diets had no influence on the substrates oxidized above resting levels during exercise. With both diets, the 24 h energy balance was slightly negative and the energy deficit was covered by lipid oxidation. 4. With the high-carbohydrate low-fat diet, the energy expenditure during sleep was found to be higher than that with the mixed diet. 5. It is concluded that: (a) the composition of the diet did not influence the fuel mixture utilized for moderate exercise, (b) the energy deficit calculated for a 24 h period was compensated by lipid oxidation irrespective of the carbohydrate content of the diet, (c) energy expenditure during sleep was found to be higher with the high-carbohydrate low-fat diet than with the mixed die
Superalgebra for M-theory on a pp-wave
We study the superalgebra of the M-theory on a fully supersymmetric pp-wave.
We identify the algebra as the special unitary Lie superalgebra, su(2|4;2,0) or
su(2|4;2,4), and analyze its root structure. We discuss the typical and
atypical representations deriving the typicality condition explicitly in terms
of the energy and other four quantum numbers. We classify the BPS multiplets
preserving 4,8,12,16 real supercharges and obtain the corresponding spectrum.
We show that in the BPS multiplet either the lowest energy floor is an su(2)
singlet or the highest energy floor is an su(4) singlet.Comment: 22 pages, 1 figure; Section on examples revised, Refs added; Typ
Realizations of the Lie superalgebra q(2) and applications
The Lie superalgebra q(2) and its class of irreducible representations V_p of
dimension 2p (p being a positive integer) are considered. The action of the
q(2) generators on a basis of V_p is given explicitly, and from here two
realizations of q(2) are determined. The q(2) generators are realized as
differential operators in one variable x, and the basis vectors of V_p as
2-arrays of polynomials in x. Following such realizations, it is observed that
the Hamiltonian of certain physical models can be written in terms of the q(2)
generators. In particular, the models given here as an example are the
sphaleron model, the Moszkowski model and the Jaynes-Cummings model. For each
of these, it is shown how the q(2) realization of the Hamiltonian is helpful in
determining the spectrum.Comment: LaTeX file, 15 pages. (further references added, minor changes in
section 5
Irreducible holonomy algebras of Riemannian supermanifolds
Possible irreducible holonomy algebras \g\subset\osp(p,q|2m) of Riemannian
supermanifolds under the assumption that \g is a direct sum of simple Lie
superalgebras of classical type and possibly of a one-dimensional center are
classified. This generalizes the classical result of Marcel Berger about the
classification of irreducible holonomy algebras of pseudo-Riemannian manifolds.Comment: 27 pages, the final versio
Estimating network related risks: A methodology and an application in the transport sector
Networks such as
transportation, water, and power are critical lifelines for society. Managers
plan and execute interventions to guarantee the operational state of their
networks under various circumstances, including after the occurrence of
(natural) hazard events. Creating an intervention program demands knowing the
probable direct and indirect consequences (i.e., risk) of the various hazard
events that could occur in order to be able to mitigate their effects. This paper
introduces a methodology to support network managers in the quantification of
the risk related to their networks. The methodology is centered on the
integration of the spatial and temporal attributes of the events that need to
be modeled to estimate the risk. Furthermore, the methodology supports the
inclusion of the uncertainty of these events and the propagation of these
uncertainties throughout the risk modeling. The methodology is implemented
through a modular simulation engine that supports the updating and swapping
of models according to the needs of network managers. This work demonstrates
the usefulness of the methodology and simulation engine through an
application to estimate the potential impact of floods and mudflows on a road
network located in Switzerland. The application includes the modeling of
(i)Â multiple time-varying hazard events; (ii)Â their physical and functional
effects on network objects (i.e., bridges and road sections); (iii)Â the
functional interrelationships of the affected objects; (iv)Â the resulting
probable consequences in terms of expected costs of restoration, cost of
traffic changes, and duration of network disruption; and (v)Â the restoration
of the network.</p
The Morphology of N=6 Chern-Simons Theory
We tabulate various properties of the language of N=6 Chern-Simons Theory, in
the sense of Polyakov. Specifically we enumerate and compute character formulas
for all syllables of up to four letters, i.e. all irreducible representations
of OSp(6|4) built from up to four fundamental fields of the ABJM theory. We
also present all tensor product decompositions for up to four singletons and
list the (cyclically invariant) four-letter words, which correspond to
single-trace operators of length four. As an application of these results we
use the two-loop dilatation operator to compute the leading correction to the
Hagedorn temperature of the weakly-coupled planar ABJM theory on R \times S^2.Comment: 41 pages, 1 figure; v2: minor correction
Metabolic effects of a mixed and a high-carbohydrate low-fat diet in man, measured over 24 h in a respiration chamber
Vaccine-Induced Immunity in Baboons by Using DNA and Replication-Incompetent Adenovirus Type 5 Vectors Expressing a Human Immunodeficiency Virus Type 1 gag Gene
This is the published version. Copyright 2003 American Society for Microbiology.The cellular immunogenicity of formulated plasmid DNA and replication-defective human adenovirus serotype 5 (Ad5) vaccine vectors expressing a codon-optimized human immunodeficiency virus type 1 gag gene was examined in baboons. The Ad5 vaccine was capable of inducing consistently strong, long-lived CD8+-biased T-cell responses and in vitro cytotoxic activities. The DNA vaccine-elicited immune responses were weaker than those elicited by the Ad5 vaccine and highly variable; formulation with chemical adjuvants led to moderate increases in the levels of Gag-specific T cells. Increasing the DNA-primed responses with booster doses of either Ad5 or modified vaccinia virus Ankara vaccines suggests a difference in the relative levels of cytotoxic and helper responses. The implications of these results are discussed
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