SamACO: variable sampling ant colony optimization algorithm for continuous optimization

An ant colony optimization (ACO) algorithm offers algorithmic techniques for optimization by simulating the foraging behavior of a group of ants to perform incremental solution constructions and to realize a pheromone laying-and-following mechanism. Although ACO is first designed for solving discrete (combinatorial) optimization problems, the ACO procedure is also applicable to continuous optimization. This paper presents a new way of extending ACO to solving continuous optimization problems by focusing on continuous variable sampling as a key to transforming ACO from discrete optimization to continuous optimization. The proposed SamACO algorithm consists of three major steps, i.e., the generation of candidate variable values for selection, the ants’ solution construction, and the pheromone update process. The distinct characteristics of SamACO are the cooperation of a novel sampling method for discretizing the continuous search space and an efficient incremental solution construction method based on the sampled values. The performance of SamACO is tested using continuous numerical functions with unimodal and multimodal features. Compared with some state-of-the-art algorithms, including traditional ant-based algorithms and representative computational intelligence algorithms for continuous optimization, the performance of SamACO is seen competitive and promising

Parameters influencing potency of Bacillus thuringiensis var. israelensis products

Bioassays of products based on #Bacillus thuringiensis var. #israelensis have been carried out according to standard protocols. Theses analyses revealed that the slopes of the log-probit transformed concentration mortality curves of various products were different from that of the international standards (IPS82 for #Bacillus thuringiensis israelensis). For statistical reasons, this invalidates the tests. Products giving various slopes of the concentration mortality curves will obtain different potencies when estimated at a LC90 level than when estimated at LC50 level, as normally done. The LC90 level is probably pore relevant for the field effect. Changing the median particle size of a product in a non destructive way results in change of slope and LC50 and thereby potency. Therefore, potency of a product as measured in these bioassays is not just a measure of the quantity of #B. thuringiensis israelensis crystal protein present, but a function of product parameters like median particle size. Biochemical methods for quantification of toxin can therefore not relate simply to potency of the products obtained with this method. It is suggested that standard protocols for bioassay may be changed to assure equal particle size of products and samples to obtain parallel close response. (Résumé d'auteur

In Vitro Effect of Sorghum (Sorghum bicolor) Seed Extracts as a Biological Acaricidal Against Some Hard Tick (Ixodidae) in Sulaimani Governorate - Kurdistan Region/Iraq

This study was conducted in Sulaimani governorate in order to identify the biological control of some Ixodidae genera among different flocks of cattle, sheep and goats. Four genera of Ixodidae; Boophilus spp., Hyalomma spp., Rhipicephalus spp. and Haemaphysalis spp., were identified in these infested animals. According to chi–square test, the highest distribution of Boophulis spp., was recorded in cattle (56.51%), and the highest distribution of Hyalomma spp., (49.82%) and Rhipicephalus spp., (28.16%) which were in sheep. The highest number of Haemophasylas spp., was obtained from goats (6.67%), whereas the lowest number of this genus (2.88% and 2.89%) was collected from cattle and sheep respectively. The toxicity of Sorghum bicolor seed extract was tested against the more distributed Ixodidae genera (Boophilus spp. and Hyalomma spp.) by immersion method on mature ticks, four concentrations (23.2, 17.4, 11.6 and 5.8 mg/dl), in addition to the control treatment (0 mg/dl) of the seed were used to evaluate the engorged females in vitro. The results showed that 100% of absolute cumulative mortality of Boophilus spp., was gain after 72 hr by 23.2 mg/dl extract concentration, followed by 17.4 mg/dl which gave 90% mortality, whereas 100% absolute cumulative mortality for Hyalomma spp., was obtained by 23.2 mg/dl extract concentration after 48 hr, followed by 17.4, 11.6 and 5.8 mg/dl concentration that gave 90%, 80% and 40% mortality after 72 hr

Phytochemical Investigation and Antioxidant Effects of Different Solvent Extracts of Pterocephalus Nestorianus Nab. Growing in Kurdistan Region-Iraq

The medicinal plants have been used as a herbal tradition in Kurdistan. Most of the medicinal plants are still not investigated from a phytochemical and biological activity. Therefore, different solvent extraction carried out to study phytochemicals and antioxidant activity of Pterocephalus nestorianus Nab. Through this research, it is reported for the first time that the phytochemicals and antioxidant activity on P. nestorianus Nab. collected at Safeen Mountain in Erbil-Iraq, which was known as a Lawa in Kurdistan. It is used against inflammation and oral diseases. The phytochemical study of four extracts (Hexane, ethyl acetate, methanol and methanol 70%) of P. nestorianus flowers, leaves and roots revealed that it contains rich phytochemical composition. C4H8O2 and CH3OH extracts of P. nestorianus showed a high radical scavenging activity compared with trihydroxy benzoic acid as a standard. The flavonoid and phenolic presence showed strong correlation with the antioxidant activity

The Nucleon Spectral Function at Finite Temperature and the Onset of Superfluidity in Nuclear Matter

Nucleon selfenergies and spectral functions are calculated at the saturation density of symmetric nuclear matter at finite temperatures. In particular, the behaviour of these quantities at temperatures above and close to the critical temperature for the superfluid phase transition in nuclear matter is discussed. It is shown how the singularity in the thermodynamic T-matrix at the critical temperature for superfluidity (Thouless criterion) reflects in the selfenergy and correspondingly in the spectral function. The real part of the on-shell selfenergy (optical potential) shows an anomalous behaviour for momenta near the Fermi momentum and temperatures close to the critical temperature related to the pairing singularity in the imaginary part. For comparison the selfenergy derived from the K-matrix of Brueckner theory is also calculated. It is found, that there is no pairing singularity in the imaginary part of the selfenergy in this case, which is due to the neglect of hole-hole scattering in the K-matrix. From the selfenergy the spectral function and the occupation numbers for finite temperatures are calculated.Comment: LaTex, 23 pages, 21 PostScript figures included (uuencoded), uses prc.sty, aps.sty, revtex.sty, psfig.sty (last included

Noncommutative Scalar Field Coupled to Gravity

A model for a noncommutative scalar field coupled to gravity is proposed via an extension of the Moyal product. It is shown that there are solutions compatible with homogeneity and isotropy to first non-trivial order in the perturbation of the star-product, with the gravity sector described by a flat Robertson-Walker metric. We show that in the slow-roll regime of a typical chaotic inflationary scenario, noncommutativity has negligible impact.Comment: Revtex4, 6 pages. Final version to appear at Phys. Rev.

Premelting of Thin Wires

Recent work has raised considerable interest on the nature of thin metallic wires. We have investigated the melting behavior of thin cylindrical Pb wires with the axis along a (110) direction, using molecular dynamics and a well-tested many-body potential. We find that---in analogy with cluster melting---the melting temperature $T_m (R)$ of a wire with radius $R$ is lower than that of a bulk solid, $T_m^b$, by $T_m (R) = T_m^b -c/R$. Surface melting effects, with formation of a thin skin of highly diffusive atoms at the wire surface, is observed. The diffusivity is lower where the wire surface has a flat, local (111) orientation, and higher at (110) and (100) rounded areas. The possible relevance to recent results on non-rupturing thin necks between an STM tip and a warm surface is addressed.Comment: 10 pages, 4 postscript figures are appended, RevTeX, SISSA Ref. 131/94/CM/S

When fecundity does not equal fitness: evidence of an offspring quantity versus quality trade-off in pre-industrial humans

Maternal fitness should be maximized by the optimal division of reproductive investment between offspring number and offspring quality. While evidence for this is abundant in many taxa, there have been fewer tests in mammals, and in particular, humans. We used a dataset of humans spanning three generations from pre-industrial Finland to test how increases in maternal fecundity affect offspring quality and maternal fitness in contrasting socio-economic conditions. For ‘resource-poor’ landless families, but not ‘resource-rich’ landowning families, maternal fitness returns diminished with increased maternal fecundity. This was because the average offspring contribution to maternal fitness declined with increased maternal fecundity for landless but not landowning families. This decline was due to reduced offspring recruitment with increased maternal fecundity. However, in landowning families, recruited offspring fecundity increased with increased maternal fecundity. This suggests that despite decreased offspring recruitment, maternal fitness is not reduced in favourable socio-economic conditions due to an increase in subsequent offspring fecundity. These results provide evidence consistent with an offspring quantity–quality trade-off in the lifetime reproduction of humans from poor socio-economic conditions. The results also highlight the importance of measuring offspring quality across their whole lifespan to estimate reliably the fitness consequences of increased maternal fecundity

On zero sets in the Dirichlet space

We study the zeros sets of functions in the Dirichlet space. Using Carleson formula for Dirichlet integral, we obtain some new families of zero sets. We also show that any closed subset of E \subset \TT with logarithmic capacity zero is the accumulation points of the zeros of a function in the Dirichlet space. The zeros satisfy a growth restriction which depends on $E$.Comment: Journal of Geometric Analysis (2011

Hydrogen Energy Storage: New Techno-Economic Emergence Solution Analysis

International audienceThe integration of various renewable energy sources as well as the liberalization of electricity markets are established facts in modern electrical power systems. The increased share of renewable sources within power systems intensifies the supply variability and intermittency. Therefore, energy storage is deemed as one of the solutions for stabilizing the supply of electricity to maintain generation-demand balance and to guarantee uninterrupted supply of energy to users. In the context of sustainable development and energy resources depletion, the question of the growth of renewable energy electricity production is highly linked to the ability to propose new and adapted energy storage solutions. The purpose of this multidisciplinary paper is to highlight the new hydrogen production and storage technology, its efficiency and the impact of the policy context on its development. A comprehensive techno/socio/economic study of long term hydrogen based storage systems in electrical networks is addressed. The European policy concerning the different energy storage systems and hydrogen production is explicitly discussed. The state of the art of the techno-economic features of the hydrogen production and storage is introduced. Using Matlab-Simulink for a power system of rated 70 kW generator, the excess produced hydrogen during high generation periods or low demand can be sold either directly to the grid owners or as filled hydrogen bottles. The affordable use of Hydrogen-based technologies for long term electricity storage is verified