84 research outputs found
Solutions of systems with the Caputo-Fabrizio fractional delta derivative on time scales
Caputo-Fabrizio fractional delta derivatives on an arbitrary time scale are
presented. When the time scale is chosen to be the set of real numbers, then
the Caputo-Fabrizio fractional derivative is recovered. For isolated or partly
continuous and partly discrete, i.e., hybrid time scales, one gets new
fractional operators. We concentrate on the behavior of solutions to initial
value problems with the Caputo-Fabrizio fractional delta derivative on an
arbitrary time scale. In particular, the exponential stability of linear
systems is studied. A necessary and sufficient condition for the exponential
stability of linear systems with the Caputo-Fabrizio fractional delta
derivative on time scales is presented. By considering a suitable fractional
dynamic equation and the Laplace transform on time scales, we also propose a
proper definition of Caputo-Fabrizio fractional integral on time scales.
Finally, by using the Banach fixed point theorem, we prove existence and
uniqueness of solution to a nonlinear initial value problem with the
Caputo-Fabrizio fractional delta derivative on time scales.Comment: This is a preprint of a paper whose final and definite form is with
'Nonlinear Analysis: Hybrid Systems', ISSN: 1751-570X, available at
[http://www.journals.elsevier.com/nonlinear-analysis-hybrid-systems].
Submitted 21/May/2018; Revised 07/Oct/2018; Accepted for publication
01-Dec-201
Universality in Systems with Power-Law Memory and Fractional Dynamics
There are a few different ways to extend regular nonlinear dynamical systems
by introducing power-law memory or considering fractional
differential/difference equations instead of integer ones. This extension
allows the introduction of families of nonlinear dynamical systems converging
to regular systems in the case of an integer power-law memory or an integer
order of derivatives/differences. The examples considered in this review
include the logistic family of maps (converging in the case of the first order
difference to the regular logistic map), the universal family of maps, and the
standard family of maps (the latter two converging, in the case of the second
difference, to the regular universal and standard maps). Correspondingly, the
phenomenon of transition to chaos through a period doubling cascade of
bifurcations in regular nonlinear systems, known as "universality", can be
extended to fractional maps, which are maps with power-/asymptotically
power-law memory. The new features of universality, including cascades of
bifurcations on single trajectories, which appear in fractional (with memory)
nonlinear dynamical systems are the main subject of this review.Comment: 23 pages 7 Figures, to appear Oct 28 201
Tunable variation of optical properties of polymer capped gold nanoparticles
Optical properties of polymer capped gold nanoparticles of various sizes
(diameter 3-6 nm) have been studied. We present a new scheme to extract size
dependent variation of total dielectric function of gold nanoparticles from
measured UV-Vis absorption data. The new scheme can also be used, in principle,
for other related systems as well. We show how quantum effect, surface atomic
co - ordination and polymer - nanoparticle interface morphology leads to a
systematic variation in inter band part of the dielectric function of gold
nanoparticles, obtained from the analysis using our new scheme. Careful
analysis enables identification of the possible changes to the electronic band
structure in such nanoparticles.Comment: 13 pages,7 figures, 1 tabl
Compendium of Current Single Event Effects Results from NASA Goddard Space Flight Center and NASA Electronic Parts and Packaging Program
We present the results of single event effects (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results
NASA Goddard Space Flight Center's Compendium of Recent Single Event Effects Results
We present the results of single event effects (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results
Electronic Structure and Bonding of Icosahedral Core-Shell Gold-Silver Nanoalloy Clusters Au_(144-x)Ag_x(SR)_60
Atomically precise thiolate-stabilized gold nanoclusters are currently of
interest for many cross-disciplinary applications in chemistry, physics and
molecular biology. Very recently, synthesis and electronic properties of
"nanoalloy" clusters Au_(144-x)Ag_x(SR)_60 were reported. Here, density
functional theory is used for electronic structure and bonding in
Au_(144-x)Ag_x(SR)_60 based on a structural model of the icosahedral
Au_144(SR)_60 that features a 114-atom metal core with 60 symmetry-equivalent
surface sites, and a protecting layer of 30 RSAuSR units. In the optimal
configuration the 60 surface sites of the core are occupied by silver in
Au_84Ag_60(SR)_60. Silver enhances the electron shell structure around the
Fermi level in the metal core, which predicts a structured absorption spectrum
around the onset (about 0.8 eV) of electronic metal-to-metal transitions. The
calculations also imply element-dependent absorption edges for Au(5d)
\rightarrow Au(6sp) and Ag(4d) \rightarrow Ag(5sp) interband transitions in the
"plasmonic" region, with their relative intensities controlled by the Ag/Au
mixing ratio.Comment: 4 figure
Toxocariasis: a silent threat with a progressive public health impact
Background: Toxocariasis is a neglected parasitic zoonosis that afflicts millions of the pediatric and adolescent populations worldwide, especially in impoverished communities. This disease is caused by infection with the larvae of Toxocara canis and T. cati, the most ubiquitous intestinal nematode parasite in dogs and cats, respectively. In this article, recent advances in the epidemiology, clinical presentation, diagnosis and pharmacotherapies that have been used in the treatment of toxocariasis are reviewed.
Main text: Over the past two decades, we have come far in our understanding of the biology and epidemiology of toxocariasis. However, lack of laboratory infrastructure in some countries, lack of uniform case definitions and limited surveillance infrastructure are some of the challenges that hindered the estimation of global disease burden. Toxocariasis encompasses four clinical forms: visceral, ocular, covert and neural. Incorrect or misdiagnosis of any of these disabling conditions can result in severe health consequences and considerable medical care spending. Fortunately, multiple diagnostic modalities are available, which if effectively used together with the administration of appropriate pharmacologic therapies, can minimize any unnecessary patient morbidity.
Conclusions: Although progress has been made in the management of toxocariasis patients, there remains much work to be done. Implementation of new technologies and better understanding of the pathogenesis of toxocariasis can identify new diagnostic biomarkers, which may help in increasing diagnostic accuracy. Also, further clinical research breakthroughs are needed to develop better ways to effectively control and prevent this serious disease
Full-order observers for linear fractional multi-order difference systems
The paper is devoted to the construction of observers for linear fractional multi–order difference systems with Riemann–Liouville– and Grünwald–Letnikov–type operators. Basing on the Z-transform method the sufficient condition for the existence of the presented observers is established. The behaviour of the constructed observer is demonstrated in numerical examples
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