Studying the effect of using low-discrepancy sequences to initialize population-based optimization algorithms

In this paper, we investigate the use of low-discrepancy sequences to generate an initial population for population-based optimization algorithms. Previous studies have found that low-discrepancy sequences generally improve the performance of a population-based optimization algorithm. However, these studies generally have some major drawbacks like using a small set of biased problems and ignoring the use of non-parametric statistical tests. To address these shortcomings, we have used 19 functions (5 of them quasi-real-world problems), two popular low-discrepancy sequences and two well-known population-based optimization methods. According to our results, there is no evidence that using low-discrepancy sequences improves the performance of population-based search methods.     

Moment condition failure in stock returns: UK evidence

We examine the issue of moments existence in the UK stock market. It is found that the second moment of stock returns is finite, and therefore, the infinite variance stable distribution is ruled out as a candidate for modelling stock returns. In contrast with the US evidence, we cannot rule out the possibility that the fourth moment is finite.     

Synthesis and extraction properties of preorganized host molecules based on tetraamides of thiacalix[4]arene

Template effect of alkali metal ions was employed to prepare three isomers of tetraamide of p-tert-butylthiacalix[4]arene: cone, partial cone and 1,3-alternate. It was demonstrated that pre-organization of four amide fragments attached to the calix[4]arene platform has a strong macrocyclic cooperative effect on the extraction ability of the title hosts.     

Sound absorption by wood in relation to anatomical and mechanical properties

The results of basic research on sound absorption by transverse and longitudinal sections of four Egyptian woods are presented. The amount of sound absorption was determined by laboratory experiments with wood samples in a standing wave apparatus. The specific gravity, maximum crushing strength and hardness of tested samples were also determined in order to study the relationship between wood absorption of sound and its mechanical properties. Cross-sections of the wood samples were also microscopically tested. The results are discussed in terms of two basic mechanisms of sound absorption—the flow resistance and mechanical hysterisis. The results show that sound absorption measurements have potential both as a non-destructive test and for the evaluation of the mechanical properties of woods.     

Electronic structure of (BP)n/(BAs)n (0 0 1) superlattices

An accurate ab initio full potential linear muffin-tin orbital method has been used to investigate the structural, electronic and optical properties of BP, BAs and their (BP)_n/(BAs)_n superlattices (SLs). The exchange-correlation potential is treated with the local density approximation of Perdew and Wang (LDA-PW). The calculated structural properties of BP and BAs compounds are in good agreement with available experimental and theoretical data. It is found that BP, BAs and their alloys exhibit an indirect fundamental band gap. The fundamental band gap decreases with increasing the number of monolayer n. The optical properties show that the static dielectric constant significantly decreases in superlattices compared to their binary compounds.     

On the Number of Trace-One Elements in Polynomial Bases for \mathbb{F}_{2^n}

This paper investigates the number of trace-one elements in a polynomial basis for . A polynomial basis with a small number of trace-one elements is desirable because it results in an efficient and low cost implementation of the trace function. We focus on the case where the reduction polynomial is a trinomial or a pentanomial, in which case field multiplication can also be efficiently implemented. Communicated by: P. Wild     

Application of Secondary Amines in the Synthesis of Some New Spiro Heterocyclic Compounds

1-Anilinocycloalkanecarbonitriles 1a–c were prepared and reacted with active methylene reagents to give compounds 5a–c through 10a–c and reacted with different other reagents such as benzaldehyde, ethyl aminoacetate, ethyl mercaptoacetate, or hydrazine carbothioamide, which afforded the desired spiro heterocycles compounds 11a–c through 14a–c.     

New Disulfiram Derivatives as MAGL-Selective Inhibitors

Monoacylglycerol lipase (MAGL) is a key enzyme in the human endocannabinoid system. It is also the main enzyme responsible for the conversion of 2-arachidonoyl glycerol (2-AG) to arachidonic acid (AA), a precursor of prostaglandin synthesis. The inhibition of MAGL activity would be beneficial for the treatment of a wide range of diseases, such as inflammation, neurodegeneration, metabolic disorders and cancer. Here, the author reports the pharmacological evaluation of new disulfiram derivatives as potent inhibitors of MAGL. These analogues displayed high inhibition selectivity over fatty acid amide hydrolase (FAAH), another endocannabinoid-hydrolyzing enzyme. In particular, compound 2i inhibited MAGL in the low micromolar range. However, it did not show any inhibitory activity against FAAH.     

Novel synthesis of thieno[2,3‐b]pyridine and substituted 2‐thienylthiourea derivatives as antibiotic agents

Derivatives of thieno[2,3‐b]pyridine, 2‐thienylthiourea, 2‐thienylurea, 2‐thienylacetamide incorporating the 2‐phthalimidomethyl moiety have been synthesized. The synthesized compounds were then investigated for antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The compounds were also investigated for antifungal activity against Aspergillus niger and Fusarium oxysporium. The structures of the newly synthesized compounds have been established on the basis of their analytical and spectral data.