2,211 research outputs found
A family of methods for solving nonlinearequations using quadratic interpolation
AbstractA two-parameter derivative-free family of methods for finding the simple and real roots of nonlinear equations is presented. The approximation process is carried out by using interpolation on three successive points (χκ, Yκ) to determine the coefficients c, d, e in the general quadratic equation aχ2 + by2 + cχ + dy + e = 0 in the terms of the coefficients a, b. Different choices of a, b correspond to different quadratic forms. Muller and inverse parabolic interpolation methods are seen as special cases of the family. Geometrical relationships with other methods are established. It is shown that the order of convergence is 1.84. Some numerical examples are given
Iterative Methods and Dynamics for Nonlinear Problems
Kim, Y.; Cordero Barbero, A.; Sharma, J.; Soleymani, F.; Torregrosa Sánchez, JR.; Wang, X. (2017). Iterative Methods and Dynamics for Nonlinear Problems. Discrete Dynamics in Nature and Society. 1-1. doi:10.1155/2017/8592140S1
Mechanical versus thermodynamical melting in pressure-induced amorphization: the role of defects
We study numerically an atomistic model which is shown to exhibit a one--step
crystal--to--amorphous transition upon decompression. The amorphous phase
cannot be distinguished from the one obtained by quenching from the melt. For a
perfectly crystalline starting sample, the transition occurs at a pressure at
which a shear phonon mode destabilizes, and triggers a cascade process leading
to the amorphous state. When defects are present, the nucleation barrier is
greatly reduced and the transformation occurs very close to the extrapolation
of the melting line to low temperatures. In this last case, the transition is
not anticipated by the softening of any phonon mode. Our observations reconcile
different claims in the literature about the underlying mechanism of pressure
amorphization.Comment: 7 pages, 7 figure
Supersonic Electroweak Baryogenesis: Achieving Baryogenesis for Fast Bubble Walls
Standard electroweak baryogenesis in the context of a first order phase
transition is effective in generating the baryon asymmetry of the universe if
the broken phase bubbles expand at subsonic speed, so that CP asymmetric
currents can diffuse in front of the wall. Here we present a new mechanism for
electroweak baryogenesis which operates for supersonic bubble walls. It relies
on the formation of small bubbles of the symmetric phase behind the bubble
wall, in the broken phase, due to the heating of the plasma as the wall passes
by. We apply the mechanism to a model in which the Higgs field is coupled to
several singlets, and find that enough baryon asymmetry is generated for
reasonable values of the parameter space
Gravitational Charged Perfect Fluid Collapse in Friedmann Universe Models
This paper is devoted to study the gravitational charged perfect fluid
collapse in the Friedmann universe models with cosmological constant. For this
purpose, we assume that the electromagnetic field is so weak that it does not
introduce any distortion into the geometry of the spacetime. The results
obtained from the junction conditions between the Friedmann and the
Reissner-Nordstrm de-Sitter spacetimes are used to solve the field
equations. Further, the singularity structure and mass effects of the
collapsing system on time difference between the formation of apparent horizons
and singularity have been studied. This analysis provides the validity of
Cosmic Censorship Hypothesis. It is found that the electric field affects the
area of apparent horizons and their time of formation.Comment: 17 pages, accepted for publication in Astrophys. Space Sc
Commercial products from bio-active extractives in cypress milling residues.
Extractive components obtained from milling residues of white cypress were studied for chemical identity and bioactivity with a view to developing a commercial use for these components, thus increasing the value of the residues and improving the economics of cypress sawn wood production. Extracts obtained by solvent or steam extraction techniques from cypress sawdust were each fractionated by a range of techniques into groups of similar compounds. Crude extracts and fractions were screened against a range of agricultural pests and diseases, including two fungi, subterranean termites, fruit spotting bugs, two-spotted mites, thrips, heliothis, banana scab moths, silverleaf whiteflies, cattle tick adults and larvae, and ruminant gastrointestinal nematodes. Additional screening was undertaken where encouraging results were achieved, for two-spotted mites, thrips, silverleaf whiteflies, cattle tick adults and ruminant gastrointestinal nematodes.
After considering degrees of efficacy against, and economic importance of, the agricultural pests, and likely production costs of extracts and fractions, the crude extract (oil) produced by steam distillation was chosen for further study against silverleaf whitefly. A useful degree of control was achievable when this oil was applied to tomato or eggplant at 0.1%, with much less harmful effects on a beneficial insect. Activity of the oil against silverleaf whitefly was undiminished 3.5 years after it was generated. There was little benefit from supplementing the extract with co-formulated paraffinic oil. From the steam distilled oil, fifty-five compounds were characterised, thirty-five compounds representing 92.478 % of the oil, with guaiol (20.8%) and citronellic acid (15.9%) most abundant. These two compounds, and a group of oxygenated compounds containing bulnesol and a range of eudesmols, were found to account for most of the activity against silverleaf whitefly. This application was recommended for first progression to commercialisation
Generation of long-living entanglement using cold trapped ions with pair cat states
With the reliance in the processing of quantum information on a cold trapped
ion, we analyze the entanglement entropy in the ion-field interaction with pair
cat states. We investigate a long-living entanglement allowing the
instantaneous position of the center-of-mass motion of the ion to be explicitly
time dependent. An analytic solution for the system operators is obtained. We
show that different nonclassical effects arise in the dynamics of the
population inversion, depending on the initial states of the vibrational
motion. We study in detail the entanglement degree and demonstrate how the
input pair cat state is required for initiating the long living entanglement.
This long living entanglement is damp out with an increase in the number
difference . Owing to the properties of entanglement measures, the results
are checked using another entanglement measure (high order linear entropy).Comment: 15 pages, 7 figures, Sub. Appl. Phys. B: Laser and Optic
Achieving food security in the face of climate change: Final report from the Commission on Sustainable Agriculture and Climate Change
To bring our interconnected food and climate systems within a ‘safe operating space’ for people and the planet, the Commission on Sustainable Agriculture and Climate Change has outlined seven major areas for policy action. Throughout 2011, the Commission worked to harvest the practical solutions detailed in the many recent authoritative reports on food security and climate change. By combining this thorough review of the substantive evidence base with the diverse perspectives and disciplinary expertise, the 13 Commissioners have crafted a succinct roadmap for policy makers. The Commission offers no ‘one-size-fits-all’ solution, but rather points the way forward to foster national, regional and sectoral innovation that can aggregate up to meaningful global change
Achieving food security in the face of climate change: Summary for policy makers from the Commission on Sustainable Agriculture and Climate Change
The Commission on Sustainable Agriculture and Climate Change has reviewed the scientific evidence to identify a
pathway to achieving food security in the context of climate change. Food systems must shift to better meet human
needs and, in the long term, balance with planetary resources. This will demand major interventions, at local to
global scales, to transform current patterns of food production, distribution and consumption. Investment,
innovation, and deliberate effort to empower the world's most vulnerable populations will be required to construct a
global food system that adapts to climate change and ensures food security while minimizing greenhouse gas
emissions and sustaining our natural resource base. Greatly expanded investments in sustainable agriculture, including
improving supporting infrastructure and restoring degraded ecosystems, are an essential component of long-term
economic development. The sooner they are made, the greater the benefits will be
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