Amenability of groups and GG-sets

This text surveys classical and recent results in the field of amenability of groups, from a combinatorial standpoint. It has served as the support of courses at the University of G\"ottingen and the \'Ecole Normale Sup\'erieure. The goals of the text are (1) to be as self-contained as possible, so as to serve as a good introduction for newcomers to the field; (2) to stress the use of combinatorial tools, in collaboration with functional analysis, probability etc., with discrete groups in focus; (3) to consider from the beginning the more general notion of amenable actions; (4) to describe recent classes of examples, and in particular groups acting on Cantor sets and topological full groups

Polyaniline/palladium nanohybrids for moisture and hydrogen detection.

Palladium nanoparticles display fascinating electronic, optical and catalytic properties, thus they can be used for various applications such as sensor fabrication. Conducting polymers such as polyaniline have also been widely used in sensor technology due to its cost effectiveness, versatility, and ease of synthesis. In this research, attention was given to unify the exceptional properties of these two materials and construct palladium nanoparticle coated polyaniline films to detect hydrogen and moisture. Electrochemical polymerization of aniline was carried out on gold sputtered epoxy resin boards. Polyaniline film was generated across a gap of 0.2 mm created by a scratch made on the gold coating prior to electrochemical polymerization. A palladium nanoparticle dispersion was prepared using sonochemical reduction method and coated on to polyaniline film using drop-drying technique. Polyaniline only films were also fabricated for comparative analysis. Sensitivity of films towards humidity and hydrogen was evaluated using impedance spectroscopy in the presence of the respective species. According to the results, polyaniline films exhibited an impedance drop in the presence of humidity and the response was significantly improved once palladium nanoparticles were incorporated. Interestingly, polyaniline only films did not respond to hydrogen. Nevertheless, palladium nanoparticle coated polyaniline films exhibited remarkable response towards hydrogen

Garotas de loja, história social e teoria social [Shop Girls, Social History and Social Theory]

Shop workers, most of them women, have made up a significant proportion of Britain’s labour force since the 1850s but we still know relatively little about their history. This article argues that there has been a systematic neglect of one of the largest sectors of female employment by historians and investigates why this might be. It suggests that this neglect is connected to framings of work that have overlooked the service sector as a whole as well as to a continuing unease with the consumer society’s transformation of social life. One element of that transformation was the rise of new forms of aesthetic, emotional and sexualised labour. Certain kinds of ‘shop girls’ embodied these in spectacular fashion. As a result, they became enduring icons of mass consumption, simultaneously dismissed as passive cultural dupes or punished as powerful agents of cultural destruction. This article interweaves the social history of everyday shop workers with shifting representations of the ‘shop girl’, from Victorian music hall parodies, through modernist social theory, to the bizarre bombing of the Biba boutique in London by the Angry Brigade on May Day 1971. It concludes that progressive historians have much to gain by reclaiming these workers and the service economy that they helped create

Electrochemically synthesized polymers in molecular imprinting for chemical sensing

This critical review describes a class of polymers prepared by electrochemical polymerization that employs the concept of molecular imprinting for chemical sensing. The principal focus is on both conducting and nonconducting polymers prepared by electropolymerization of electroactive functional monomers, such as pristine and derivatized pyrrole, aminophenylboronic acid, thiophene, porphyrin, aniline, phenylenediamine, phenol, and thiophenol. A critical evaluation of the literature on electrosynthesized molecularly imprinted polymers (MIPs) applied as recognition elements of chemical sensors is presented. The aim of this review is to highlight recent achievements in analytical applications of these MIPs, including present strategies of determination of different analytes as well as identification and solutions for problems encountered

Yield and quality of winter oilseed rape in response to different systems of foliar fertilization

The aim of this study was to determine the effect of different systems of foliar fertilization on the yield of winter oilseed rape (Brassica napus L.), the mineral composition of post-harvest biomass and the processing suitability of seeds. In winter oilseed rape grown on boulder clay, intensified foliar fertilization increased seed yield (by 0.43-0.69 Mg ha-1 87% dry matter, DM), straw yield (by 0.59-1.69 Mg ha-1 DM), and decreased the harvest index (by 2-3%). The seeds of winter oilseed rape accumulated more N, P, Ca, Zn, Cu, Mn and Fe than straw. The concentrations of P, Mg and S were higher in straw than in seeds. Foliar fertilization increased the N, P and K content (by 2.0, 0.35 and 1.15 g kg-1 DM, respectively) and decreased the Mg and S content of straw (by 2.08 and 0.77 g kg-1 DM, respectively). A chemical analysis of seeds revealed significant changes only in the concentrations of K, S (increase by 0.57 and 0.55 g kg-1 DM, respectively) and P (decrease by 0.90 g kg-1 DM, respectively) under the influence of foliar fertilization. Intensified foliar fertilization increased the concentrations of Cu and Zn and decreased the levels of Mn and Fe in straw and seeds. The nutritional value of seeds deteriorated (crude fat content decreased by around 5.5 g kg-1 DM, but the composition of fatty acids (FAs), and the proportions of saturated FAs, monounsaturated FAs and polyunsaturated FAs were not significantly altered) with an increase in foliar fertilization levels. Foliar application of macronutrients and micronutrients improved the feed value of winter oilseed rape seeds. Intensified foliar fertilization reduced the content of alkenyl (by approx. 47%) and indole (by approx. 6%) glucosinolates in seeds, mostly due to a decrease in the concentrations of progoitrin, gluconapin and 4-OH-glucobrassicin

Spectral multipliers for a distinguished Laplacian on certain groups of exponential growth

We prove that on Iwasawa AN groups coming from arbitrary semisimple Lie groups there is a Laplacian with a nonholomorphic functional calculus, not only for L^1(AN), but also for L^p(AN), where 1<p< 1e. This yields a spectral multiplier theorem analogous to the ones known for sublaplacian on stratified groups