Ergodicity properties of pp -adic (2,1)(2,1)-rational dynamical systems with unique fixed point

We consider a family of $(2,1)$-rational functions given on the set of $p$-adic field $Q_p$. Each such function has a unique fixed point. We study ergodicity properties of the dynamical systems generated by $(2,1)$-rational functions. For each such function we describe all possible invariant spheres. We characterize ergodicity of each $p$-adic dynamical system with respect to Haar measure reduced on each invariant sphere. In particular, we found an invariant spheres on which the dynamical system is ergodic and on all other invariant spheres the dynamical systems are not ergodic

Antibacterial Activity of Culture Extracts of Penicillium chrysogenum PCL501: Effects of Carbon Sources

Penicillium chrysogenum PCL501 produced β-lactam antibiotics when fermented with different agro-wastes: cassava shavings, corncob, sawdust and sugarcane pulp. In vitro antibacterial activity of the culture extracts was tested against four clinical bacterial isolates, namely, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. All the culture extracts and standard drug (commercial Benzyl Penicillin) inhibited the growth B. subtilis and E. coli; the potency varied with carbon source. Antibacterial activity of extracts from cultures containing cassava shavings and sugarcane pulp was comparable with that of the standard drug. The MIC against the susceptible organisms was 0.20mg/ml for the standard drug and ranged from 0.40 to 1.50mg/ml for the culture extracts. Neither the culture extracts nor the standard drug inhibited K. pneumoniae and P. aeruginosa; the bacterial strains produced β-lactamase enzymes. Cassava shavings and sugarcane pulp are indicated as suitable cheap carbon sources for the production of antibiotics by Penicillium chrysogenum PCL501

Local and global stability indices for a riddled basin attractor of a piecewise linear map

AcceptedArticleWe consider a piecewise expanding linear map with a Milnor attractor whose basin is riddled with the basin of a second attractor. To characterize the local geometry of this riddled basin, we calculate a stability index for points within the attractor as well as introducing a global stability index for the attractor as a set. Our results show that for Lebesgue almost all points in attractor the index is positive and we characterise a parameter region where some points have negative index. We show there exists a dense set of points for which the index is not converge. Comparing to recent results of Keller, we show that the stability index for points in the attractor can be expressed in terms of a global stability index for the attractor and Lyapunov exponents for this point.University of ExeterMinistry of Education MalaysiaUniversiti Malaysia Terenggan

Uniqueness of Gibbs Measure for Models With Uncountable Set of Spin Values on a Cayley Tree

We consider models with nearest-neighbor interactions and with the set $[0,1]$ of spin values, on a Cayley tree of order $k\geq 1$. It is known that the "splitting Gibbs measures" of the model can be described by solutions of a nonlinear integral equation. For arbitrary $k\geq 2$ we find a sufficient condition under which the integral equation has unique solution, hence under the condition the corresponding model has unique splitting Gibbs measure.Comment: 13 page

Testing Asset Pricing Models in Emerging Markets: An Examination of Higher Order Co-Moments and Alternative Factor Models

For emerging market returns there is strong evidence that the departure from normality is primarily driven by kurtosis and not skewness. This paper investigates the empirical validity of a return generating process that includes quadratic and cubic market returns as factors of pricing for an emerging market. Following Barone-Adesi et al. (2004) a multivariate test of a three-moment pricing model is developed. The empirical evidence in the market returns support the stylized facts typical for an emerging market and reveal that any return generating process that includes only a quadratic term (coskewness) may be misspecified. However comparison of higher order market return factors with Fama French factors indicates that while risk exposure to these higher order co-moments factors especially cokurtosis is important the co-moments do not possess sufficient explanatory power to render Fama French factor redundant.Higher Order Co-Moments, Asset Pricing, Emerging Markets

Self-sustained hydrodynamic oscillations in lifted jet diffusion flames: Origin and control

We use direct numerical simulation (DNS) of the Navier–Stokes equations in the low-Mach-number limit to investigate the hydrodynamic instability of a lifted jet diffusion flame. We obtain steady solutions for flames using a finite rate reaction chemistry, and perform a linear global stability analysis around these steady flames. We calculate the direct and adjoint global modes and use these to identify the regions of the flow that are responsible for causing oscillations in lifted jet diffusion flames, and to identify how passive control strategies might be used to control these oscillations. We also apply a local stability analysis to identify the instability mechanisms that are active. We find that two axisymmetric modes are responsible for the oscillations. The first is a high-frequency mode with wavemaker in the jet shear layer in the premixing zone. The second is a low-frequency mode with wavemaker in the outer part of the shear layer in the flame. We find that both of these modes are most sensitive to feedback involving perturbations to the density and axial momentum. Using the local stability analysis, we find that the high-frequency mode is caused by a resonant mode in the premixing region, and that the low-frequency mode is caused by a region of local absolute instability in the flame, not by the interaction between resonant modes, as proposed in Nichols et al. (Phys. Fluids, vol. 21, 2009, article 015110). Our linear analysis shows that passive control of the low-frequency mode may be feasible because regions up to three diameters away from the fuel jet are moderately sensitive to steady control forces.This work was funded by the European Research Council through project ALORS 2590620.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/jfm.2015.29

Porosity enhancement of biochar derived from rubber sawdust using steam injection at low temperature

Biochar is extremely interesting for energy and environment applications such assoil amender, sorbent materials and biofuels. In this study, rubber sawdust (RS) was prepared through the pyrolysis at 400 and 600°C with low and high heating rate (7 and 20°C/min) for 60 minutes.The pyrolytic parameters have a strong influence on biochar properties. Biochar yield was decreased from 33.1 to 22.6 wt% due to increasing of pyrolytic temperature. The higest BET surface area of biochar previous enhanced porosity was found about 410 m2/g at 600°C with 20°C/min of heating rate with particle size 0.3-1 mm. Afterwards, biochar porosity was enhanced through the steam injection process. Furthermore, the physicochemical properties of biochar product (i.e. surface morphology, BET surface area, and N2adsorption isotherm) will be characterized. (Texte intégral

Porosity enhancement of biochar derived from rubber sawdust using steam injection at low temperature

Biochar is extremely interesting for energy and environment applications such assoil amender, sorbent materials and biofuels. In this study, rubber sawdust (RS) was prepared through the pyrolysis at 400 and 600°C with low and high heating rate (7 and 20°C/min) for 60 minutes.The pyrolytic parameters have a strong influence on biochar properties. Biochar yield was decreased from 33.1 to 22.6 wt% due to increasing of pyrolytic temperature. The higest BET surface area of biochar previous enhanced porosity was found about 410 m2/g at 600°C with 20°C/min of heating rate with particle size 0.3-1 mm. Afterwards, biochar porosity was enhanced through the steam injection process. Furthermore, the physicochemical properties of biochar product (i.e. surface morphology, BET surface area, and N2adsorption isotherm) will be characterized. (Texte intégral

Draft environmental report on Cape Verde

Faced with recurrent drought and famine during five centuries of human occupation, the small and densely populated Cape Verde Islands have a history of severe environmental problems. The arid climate and steep, rocky terrain provide scant resources for traditional subsistance farming under the best conditions, and in years of low rainfall the failure of rainfed crops causes massive food shortages. Agricultural use of steep slopes where rainfall is highest has led to soil erosion, as has removal of the island's vegetation for fuel and livestock. Pressure on the vegetation is particularly severe in dry years. International aid can provide relief from famine, and the introduction of modern agricultural and conservation techniques can improve the land and increase yield, but it is unlikely that Cape Verde can ever be entirely self -sufficient in food. Ultimately, the solution of Cape Verde's economic and environmental problems will probably require the development of productive urban jobs so the population can shift away from the intensive and destructive use of land for subsistance farming. In the meantime, the people of Cape Verde can best be served by instituting fundamental measures to conserve and restore the land so that it can be used to its fullest potential. The primary environmental problems in Cape Verde today are: 1. Soil degradation. Encouraged by brief but heavy rains and steep slopes, soil erosion is made worse by lack of vegetation. Soils are also low in organic matter due to the practice of completely removing crop plants and natural vegetation for food, fuel or livestock feed. 2. Water shortage. Brief and erratic rainfall in combination with rapid runoff makes surface water scarce and difficult to use. Groundwater supplies can be better developed but capabilities are poorly known and the complex nature of the geological substrate makes estimation difficult. Water is the critical limiting factor to the agricultural capability of the islands. 3. Fuel shortage. Demand for fuel is intense and has resulted in the virtual elimination of native vegetation. Fuelwood supplies are becoming more and more scarce and costly. Development of managed fuelwood plantations and alternate energy sources is required. 4. Inappropriate land use. Much of the land now used for raising crops or livestock is too steep or too arid for these purposes, causing erosion and destruction of vegetation. Improving yield in more appropriate areas and encouraging less damaging uses of the remaining marginal lands can help to alleviate this problem

Jet coherence in QCD media: the antenna radiation spectrum

We study the radiation of a highly energetic partonic antenna in a colored state traversing a dense QCD medium. Resumming multiple scatterings of all involved constituents with the medium we derive the general gluon spectrum which encompasses both longitudinal color coherence between scattering centers in the medium, responsible for the well known Landau-Pomeranchuk-Migdal (LPM) effect, and transverse color coherence between partons inside a jet, leading, in vacuum, to angular ordering of the parton shower. We discuss shortly the onset of transverse decoherence which is reached in opaque media. In this regime, the spectrum consists of independent radiation off the antenna constituents.Comment: 15 pages, 2 figures, paper shortened and partly rewritten, references added, results unchange