100 years of microbial electricity production : three concepts for the future

Bioelectrochemical systems (BES) have been explored according to three main concepts: to produce energy from organic substrates, to generate products and to provide specific environmental services. In this work, by using an engineering approach, biological conversion rates are calculated for BES resp. anaerobic digestion. These rates are compared with currents produced by chemical batteries and chemical fuel cells in order to position BES in the energy-market. To evaluate the potential of generating various products, the biochemistry behind the biological conversion rates is examined in relation to terminal electron transfer molecules. By comparing kinetics rather than thermodynamics, more insight is gained in the biological bottlenecks that hamper a BES. The short-term future for BES research and its possible application is situated in smart niches in sustainable environmental development, i.e. in processes where no large currents or investment cost intensive reactors are needed to obtain the desired results. Some specific examples are identified

International Large Scale Assessment of Vocational Education and Training (VET-LSA)

Berufsausbildung, Bildungsniveau, Vergleich, Europa, Vocational training, Educational level, Comparison, Europe

netgwas: An R Package for Network-Based Genome-Wide Association Studies

Graphical models are powerful tools for modeling and making statistical inferences regarding complex associations among variables in multivariate data. In this paper we introduce the R package netgwas, which is designed based on undirected graphical models to accomplish three important and interrelated goals in genetics: constructing linkage map, reconstructing linkage disequilibrium (LD) networks from multi-loci genotype data, and detecting high-dimensional genotype-phenotype networks. The netgwas package deals with species with any chromosome copy number in a unified way, unlike other software. It implements recent improvements in both linkage map construction (Behrouzi and Wit, 2018), and reconstructing conditional independence network for non-Gaussian continuous data, discrete data, and mixed discrete-and-continuous data (Behrouzi and Wit, 2017). Such datasets routinely occur in genetics and genomics such as genotype data, and genotype-phenotype data. We demonstrate the value of our package functionality by applying it to various multivariate example datasets taken from the literature. We show, in particular, that our package allows a more realistic analysis of data, as it adjusts for the effect of all other variables while performing pairwise associations. This feature controls for spurious associations between variables that can arise from classical multiple testing approach. This paper includes a brief overview of the statistical methods which have been implemented in the package. The main body of the paper explains how to use the package. The package uses a parallelization strategy on multi-core processors to speed-up computations for large datasets. In addition, it contains several functions for simulation and visualization. The netgwas package is freely available at https://cran.r-project.org/web/packages/netgwasComment: 32 pages, 9 figures; due to the limitation "The abstract field cannot be longer than 1,920 characters", the abstract appearing here is slightly shorter than that in the PDF fil

Adsorption of aminefluorides onto glass and the determination of surface free energy, zeta potential and adsorbed layer thickness

Aminefluorides are known to affect bacterial adhesion to enamel. In order to obtain information on the structure of adsorbed aminefluoride coatings, dihydroaminefluoride (AmF 297) and oleylaminefluoride (AmF 335) were adsorbed onto glass from solutions with concentrations up to 10 mM. Surface tensions of the solutions were measured at 25°C. After coating the glass surfaces, surface free energies, zeta potentials and adsorbed layer thicknesses were determined from contact angles, electrophoresis and ellipsometry, respectively. Surface free energies decreased after coating with both types of aminefluoride from 109 to _ 45 mJ m-*. Coating with only high concentrations (> 5 mA4) of AmF 297 again resulted in surface free energies above 100 mJ m-‘. Zeta potentials, originally - 45 mV, became positive after coating with both types of aminefluoride (approximately + 5 mV). Coating with only AmF 297 at concentrations above 5 mM gave zeta potentials of + 20 mV. Adsorbed layer thicknesses were in the monolayer range, though AmF 297 on its own clearly formed thicker layers at higher concentrations. Both surfactants showed a tendency to form micelles in solution at concentrations higher than 1 n&f. The results indicate that both aminefluorides adsorb with the positively charged, polar group towards the glass, but only AmF 297 can form double layers at higher concentrations. The second layer, however, adsorbs with the positively charged polar groups towards the solution and is bound to the first layer by relatively weak forces between the hydrocarbon chains. Gentle rinsing with distilled water is sufficient to remove the double layers. This paper shows how a combination of surface techniques can yield a detailed picture of the structure and orientation of adsorbed layers on solid substrata

Do crowded classrooms crowd out learning?

The concern that learning performance may be adversely affected by increased class size appears to be unfounded. But unchecked, the negative peer effect could hinder student achievement.Education Bangladesh ,School children Food ,Nutrition programs ,Food aid ,

Do crowded classrooms crowd out learning?

The concern that learning performance may be adversely affected by increased class size appears to be unfounded. But unchecked, the negative peer effect could hinder student achievement.Education Bangladesh ,School children Food ,Nutrition programs ,Food aid ,

Teachers'salaries in Latin America : a comparative analysis

Data from household surveys of 12 Latin American countries were used to assess how teachers'salaries compare with those of workers in other occupations. The results show that salaries vary among countries, ranging from an apparent 35 percent underpayment in Bolivia (compared with the contol group) to a 65 percent overypayment in Colombia. But when statistical controls are introduced for differences in education, hours worked, and gender composition between the teachers group and the comparator group, much of the earnings differential disappears. The authors conclude that the data do not support the position that teachers are either overpaid or underpaid.Teaching and Learning,Skills Development and Labor Force Training,Gender and Education,ICT Policy and Strategies,Primary Education

Spreading pressures of water and n-propanol on polymer surfaces

Spreading pressures of water and n-propanol on polytetrafluoroethylene (PTFE), polystyrene (PS), polymethylmethacrylate (PMMA), polycarbonate (PC), and glass are determined from ellipsometrically measured adsorption isotherms by graphical integration, yielding for water 9, 37, 26, 33, and 141 erg · cm−2 on PTFE, PS, PMMA, PC, and glass, respectively, while for n-propanol 5, 38, 26, 23, and 37 erg · cm−2, respectively. The spreading pressures for water as well as n-propanol are comparable to values previously obtained from contact angle data with water, water/n-propanol mixtures and α-bromonaphthalene using the geometric mean equation. This method yielded spreading pressures of 9, 14, 30, 27, and 70 erg · cm−2 for PTFE, PS, PMMA, PC, and glass, respectively. The numerical correspondence between the spreading pressures for water and n-propanol determined ellipsometrically with the values derived from contact angles indicates the necessity as well as the validity of taking the spreading pressures of water/n-propanol mixtures into account as a constant, if surface free energies of high energy substrata are approximated by contact angle measurements