A new stochastic algorithm inspired on genetic algorithms to estimate signals with finite rate of innovation from noisy samples

In early 2000, it was shown that it is possible to develop exact sampling schemes for a large class of parametric non-bandlimited noiseless signals, namely certain signals of finite rate of innovation. In particular, signals x(t) that are linear combinations of a finite number of Diracs per unit of time can be acquired by linear filtering followed by uniform sampling. However, when noise is present, many of the early proposed schemes can become ill-conditioned. Recently, a novel stochastic algorithm based on Gibbs sampling was proposed by Tan & Goyal [IEEE Trans. Sign. Proc., 56 (10) 5135] to recover the filtered signal z(t) of x(t) by observing noisy samples of z(t). In the present paper, by blending together concepts of evolutionary algorithms with those of Gibbs sampling, a novel stochastic algorithm which substantially improves the results in the cited reference is proposed.     

Fabrication of Multifunctional Composite Nanofibers by Green Electrospinning

The present work takes advantage of green electrospinning to create novel composite multifunctional nanofibers (NFs) bearing inorganic nanoparticles (NPs), more specifically quantum dots (QDs), cerium oxide nanoparticles (CeO₂ NPs) and iron oxide nanoparticles (Fe₃O₄ NPs). This is achieved by first encapsulating the desired inorganic NPs into polymer particles by the use of miniemulsion polymerization, and second, spinning the hybrid polymer particles using polyvinyl alcohol (PVA) as template polymer. It is proved that using green electrospinning, it is not only possible to ensure an excellent distribution and encapsulation of the inorganic NPs along the NFs, but also allows to control and change the concentration, size, and type of the inorganic NPs without altering the NFs size, a fact that is not possible by conventional solution electrospinning. As proof of concept, NFs with up to three different types of inorganic NPs have been created in a single electrospinning step, but this technology allows to incorporate as much inorganic NPs as desired without altering the NFs morphology and ensuring a good distribution and encapsulation of the NPs. This paper demonstrates that green electrospinning is a powerful and attractive technology to create multifunctional NFs that are promising materials for sensing and biomedical applications.     

Scheduling in sports: An annotated bibliography

Sports have worldwide appeal. Professional sport leagues involve significant investments in players. Events such as the Olympics Games, the Football World Cup and the major golf and tennis tournaments generate huge worldwide television audiences and many sports are multi-million dollar industries. A key aspect of sporting events is the ability to generate schedules that optimize logistic issues and that are seen as fair to all those who have an interest. This is not just restricted to generating the fixtures, but also to other areas such as assigning officials to the games in the competitions. This paper provides an annotated bibliography for sports scheduling articles. This area can be traced back over 40 years. It is noticeable that the number of papers has risen in recent years, demonstrating that scientific interest is increasing in this area.     

Theoretical chemical characterization of phosphate-metal-humic complexes and relationships with their effects on both phosphorus soil fixation and phosphorus availability for plants

BACKGROUND: Previous studies showed that phosphate can be complexed by humic acids (HA) through stable metal (M) bridges (PMHA). We studied the thermodynamic properties of PMHA and their relationships with the ability of PMHA to both decrease soil P fixation and increase P availability for plants. With this aim, we studied the theoretical stability of PFeHA, PAlHA and PCaHA by molecular modelling methods in relation to the degree and intensity of P absorption in soils and the ability of plants to take up complexed P. RESULTS: A density functional theory (DFT) quantum chemical study enabled us to obtain stable structures for the three PMHA complexes in water solution. The theoretical stabilities (ΔG⁰) were consistent with that for apparent stability obtained by Scatchard method, PFeHA ≥ PAlHA > PCaHA, though the differences were clearer by the DFT method. Also the reduction of soil P fixation and the release of P from PMHA in the presence of an anionic resin confirmed the stability order of the different PMHA. Plant studies confirmed the ability of diverse plant species to take up both P and metal complexed in PMHA. CONCLUSION: The results indicated the potential efficiency of PMHA‐based fertilizers to optimize P fertilization for crops cultivated in soils with high P fixation ability. Copyright © 2012 Society of Chemical Industry     

Influence of chitosan derivatization on its physicochemical characteristics and its use as enzyme support

Chitosan was derivatized by two methodologies for analyzing their effect on chitosan physicochemical characteristics and its applicability as carrier for Bacillus circulans β‐galactosidase immobilization. Glutaraldehyde (GA) and epichlorohydrin (EPI) were used for crosslinking and activation of chitosan, producing the corresponding supports (C‐GA and C‐EPI‐EPI) after a one‐step and a two‐step process, respectively. The spherical shape and mean diameter of chitosan particles was not significantly affected by polymer derivatization, while Fourier transform infrared analysis showed that in both cases, chitosan polymer was chemically modified. TGA analysis indicated that C‐EPI‐EPI was the most thermally stable. The high degree of activation of C‐EPI‐EPI (586 μmol of aldehydes/g) resulted in the highest loss of activity during immobilization; hence a support with 100 μmol of aldehydes/g was produced (C‐EPI‐EPI₁₀₀). The highest expressed activity (89.3 IU/g) was obtained with the enzyme immobilized in C‐GA, while the biocatalyst with highest thermal stability at 60°C was obtained with C‐EPI‐EPI₁₀₀ (half‐life was 84‐fold higher than the one of the soluble enzyme). The best compromise between biocatalyst expressed activity and thermal stability corresponded to β‐galactosidase immobilized in C‐EPI‐EPI₁₀₀. According to this study, chitosan derivatized with EPI is a thermally stable carrier appropriate for producing highly stable immobilized B. circulans β‐galactosidase. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40171.     

A Methodology for Building Translator-oriented Dictionary Systems

Interaction between humans and translation tools has been deeply studied in the field of machine-aided translation. However, support tools for translation are often designed without the co-operation of human translators. The underlying idea is that human translators must adapt to the new technologies, and it seems that new computerised tools would not need to consider translators' practical use and experience. On the contrary, we argue that it is worthwhile and necessary to analyse the behaviour of translators in order to fit the tools to their needs. This paper presents an experiment to incorporate human translators' expertise into an already constructed lexical system. We focus on the design methodology that could be applied for the improvement of other similar tools.     

Evolution of the film properties of 3-methacryloxypropyl trimethoxysilane containing waterborne acrylic coatings during storage

The use of alkoxysilane monomers is one of the most attractive methods to obtain one-pot self-crosslinkable latexes for coating applications. The copolymerization kinetics shows that the alkoxysilane monomer is effectively incorporated into the copolymer. However, the hydrolysis and condensation reactions that give the latex the self-crosslinking ability can also prematurely happen. As a result, the microstructure of the latex, and consequently of the dried polymer film, will change during the storage. Herein, the evolution of key film properties, such as, water uptake and tensile strength as a function of the storage time of latexes with different alkoxysilane monomer loadings is presented. As storage time increases, there is an improvement on the mechanical properties, obtaining a harder polymer as the result of the development of the hydrolysis and condensation reactions during the first 4 weeks. However, for more extended storage periods (17 weeks) there is a significant decrease in the mechanical performance, because the crosslinking in the latex has developed enough to hinder the film formation.     

An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles

This work presents an alternative approach for fabricating electrospun submicron highly hydrophilic fiber mats loaded with silver nanoparticles. These fiber mats show a high efficient antibacterial behavior, very attractive for applications like wound healing and skin regeneration processes. The fabrication method is divided in two steps. First, poly(acrylic acid) (PAA) and β‐cyclodextrin (β‐CD) submicron fibers were electrospun and further stabilized using a thermal treatment, yielding stable hydrogel‐like fibers with diameters ranging from 100 nm up to several microns. In the second step, silver ions were loaded into the fibers and then reduced to silver nanoparticles in‐situ. The electrospinning parameters were adjusted to achieve the desired properties of the fiber mat (density, size) and afterwards, the characteristics of the silver nanoparticles (amount, size, aggregation) were tuned by controlling the silver ion loading mechanism. Highly biocide surfaces were achieved showing more than 99.99% of killing efficiency. The two‐step process improves the reproducibility and tunability of the fiber mats. To our knowledge, this is the first time that stable hydrogel fibers with a highly biocide behavior have been fabricated using electrospinning. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of imipenem and sulbactam on sessile cells of Acinetobacter baumannii growing in biofilm

The effect of the age of biofilms formed by Acinetobacter baumannii on the activity of sulbactam and imipenem on sessile cells was investigated. Against cells of young biofilms both antibiotics were rapidly bactericidal. As the biofilm aged, sulbactam lost most of its activity, but imipenem continued to be bactericidal to some extent. This fact probably reflects the ability of imipenem to exert bactericidal activity on slow-growing bacteria.