15,375 research outputs found
Optimization Aspects of Carcinogenesis
Any process in which competing solutions replicate with errors and numbers of
their copies depend on their respective fitnesses is the evolutionary
optimization process. As during carcinogenesis mutated genomes replicate
according to their respective qualities, carcinogenesis obviously qualifies as
the evolutionary optimization process and conforms to common mathematical
basis. The optimization view accents statistical nature of carcinogenesis
proposing that during it the crucial role is actually played by the allocation
of trials. Optimal allocation of trials requires reliable schemas' fitnesses
estimations which necessitate appropriate, fitness landscape dependent,
statistics of population. In the spirit of the applied conceptual framework,
features which are known to decrease efficiency of any evolutionary
optimization procedure (or inhibit it completely) are anticipated as
"therapies" and reviewed. Strict adherence to the evolutionary optimization
framework leads us to some counterintuitive implications which are, however, in
agreement with recent experimental findings, such as sometimes observed more
aggressive and malignant growth of therapy surviving cancer cells
Overlaps after quantum quenches in the sine-Gordon model
We present a numerical computation of overlaps in mass quenches in
sine-Gordon quantum field theory using truncated conformal space approach
(TCSA). To improve the cut-off dependence of the method, we use a novel running
coupling definition which has a general applicability in free boson TCSA. The
numerical results are used to confirm the validity of a previously proposed
analytical Ansatz for the initial state in the sinh-Gordon quench.Comment: 13 pages, 4 pdf figure
Compatibility of alternative fuels with advanced automotive gas turbine and stirling engines. A literature survey
The application of alternative fuels in advanced automotive gas turbine and Stirling engines is discussed on the basis of a literature survey. These alternative engines are briefly described, and the aspects that will influence fuel selection are identified. Fuel properties and combustion properties are discussed, with consideration given to advanced materials and components. Alternative fuels from petroleum, coal, oil shale, alcohol, and hydrogen are discussed, and some background is given about the origin and production of these fuels. Fuel requirements for automotive gas turbine and Stirling engines are developed, and the need for certain reseach efforts is discussed. Future research efforts planned at Lewis are described
Creating temperature dependent Ni-MH battery models for low power mobile devices
In this paper the methodology and the results of creating temperature
dependent battery models for ambient intelligence applications is presented.
First the measurement technology and the model generation process is presented
in details, and then the characteristic features of the models are discussed.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Initial states in integrable quantum field theory quenches from an integral equation hierarchy
We consider the problem of determining the initial state of integrable
quantum field theory quenches in terms of the post-quench eigenstates. The
corresponding overlaps are a fundamental input to most exact methods to treat
integrable quantum quenches. We construct and examine an infinite integral
equation hierarchy based on the form factor bootstrap, proposed earlier as a
set of conditions deter- mining the overlaps. Using quenches of the mass and
interaction in Sinh-Gordon theory as a concrete example, we present theoretical
arguments that the state has the squeezed coherent form expected for integrable
quenches, and supporting an Ansatz for the solution of the hierarchy. Moreover
we also develop an iterative method to solve numerically the lowest equation of
the hierarchy. The iterative solution along with extensive numerical checks
performed using the next equation of the hierarchy provide a strong numerical
evidence that the proposed Ansatz gives a very good approximation for the
solution.Comment: 36 pages, pdflatex file, 11 pdf figures. v2: revised version,
accepted for publicatio
Major loop reconstruction from switching of individual particles
Major hysteresis loops of groups of isolated 60 mm square garnet particles of a regular
two-dimensional array, have been measured magnetooptically. Individual loops for each particle
were measured, and the statistics of the distribution of coercivities and interaction fields was
determined. It is shown that from the measured coercivity distribution and calculated magnetostatic
interaction fields the major hysteresis loop can be reconstructed. The switching sequence, and the
major loop of an assembly of 535 particles were calculated numerically for two cases: first, when
calculating the magnetostatic interaction, the 25 particles were assumed to be isolated; second, the
major loop of the same 25 particles, embedded into a 939 square, was reconstructed taking into
account the interactions among all 81 particles. The numerically simulated major hysteresis loops
agree very well with the measured loops, demonstrating the reliability of numerical modeling
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