Netiquette Between Students and Their Lecturers on Facebook: Injunctive and Descriptive Social Norms

There is an ongoing discussion if and how students and lecturers should interact with each other on social networks. In this article, we present an empirical study on the so-called netiquette for Facebook contacts between students and their lecturers (hereinafter called SL-contacts). In addition, we investigated the subjective perception of the majority’s behavior. This enabled a comparison between two different kinds of social norms: the injunctive norms (netiquette) and the descriptive norms (majority). Database was an online survey with 2,849 participants (2,550 students and 299 lecturers). SL-contacts were quite rare in our sample and usually initiated by students. Our results showed that the appropriateness of SL-contacts depends on the individual case. In addition, we found that injunctive and descriptive norms are in line with each other. Overall, our results indicate that there is a common ground of understanding, and SL-contacts are less critical than they might appear

AAscan, PCRdesign and MutantChecker: A Suite of Programs for Primer Design and Sequence Analysis for High-Throughput Scanning Mutagenesis

Scanning mutagenesis is a powerful protein engineering technique used to study protein structure-function relationship, map binding sites and design more stable proteins or proteins with altered properties. One of the time-consuming tasks encountered in application of this technique is the design of primers for site-directed mutagenesis. Here we present an open-source multi-platform software AAscan developed to design primers for this task according to a set of empirical rules such as melting temperature, overall length, length of overlap regions, and presence of GC clamps at the 3’ end, for any desired substitution. We also describe additional software tools which are used to analyse a large number of sequencing results for the presence of desired mutations, as well as related software to design primers for ligation independent cloning. We have used AAscan software to design primers to make over 700 mutants, with a success rate of over 80%. We hope that the open-source nature of our software and ready availability of freeware tools used for its development will facilitate its adaptation and further development. The software is distributed under GPLv3 licence and is available at http://www.psi.ch/lbr/aascan.ISSN:1932-620

RNA polymerase I-specific subunits promote polymerase clustering to enhance the rRNA gene transcription cycle.

RNA polymerase I (Pol I) produces large ribosomal RNAs (rRNAs). In this study, we show that the Rpa49 and Rpa34 Pol I subunits, which do not have counterparts in Pol II and Pol III complexes, are functionally conserved using heterospecific complementation of the human and Schizosaccharomyces pombe orthologues in Saccharomyces cerevisiae. Deletion of RPA49 leads to the disappearance of nucleolar structure, but nucleolar assembly can be restored by decreasing ribosomal gene copy number from 190 to 25. Statistical analysis of Miller spreads in the absence of Rpa49 demonstrates a fourfold decrease in Pol I loading rate per gene and decreased contact between adjacent Pol I complexes. Therefore, the Rpa34 and Rpa49 Pol I–specific subunits are essential for nucleolar assembly and for the high polymerase loading rate associated with frequent contact between adjacent enzymes. Together our data suggest that localized rRNA production results in spatially constrained rRNA production, which is instrumental for nucleolar assembly

Drain Field Plate Impact on the Hard-Switching Performance of AlGaN/GaN HEMTs

In this work, an analysis of the impact of drain field plate (FP) length on the semi-ON degradation of AlGaN/GaN high-electron-mobility transistors (HEMTs) is performed. A wafer-level characterization, by means of pulsed stress tests, reveals a faster and more severe decrease of the drain current in the linear region for the samples with longer drain FP. 2-D technology computer-aided design (TCAD) hydrodynamic simulations show that a time and field-dependent hot electrons (HEs) trapping takes place at the passivation/barrier interface. The higher drain current decrease in the longer FP samples can be ascribed to an enhanced HE trapping at the drain FP edge due to a different electric field distribution