Horizontal Stratification in Access to Danish University Programmes

In this paper, we use register data to examine horizontal stratification within university institutions and university fields of study in Denmark, a country that has experienced a reduction of the social class gap in access to higher education. First, we argue that it is important to use a relatively detailed classification of parents’ occupations to determine how students are endowed with different forms of capital, even when their parents would typically be characterised as belonging to the same social group. Second, we distinguish among disciplines and among university institutions to explain the dynamics of horizontal stratification in the Danish university system. Using unique and exhaustive register data, including all higher education institutions and the entire 1984 cohort as of the age of 24, we uncover distinct differences in the magnitude and type of horizontal stratification in different fields of study and university institutions. Most importantly, we find distinct patterns of horizontal stratification by field of study and parental occupation that would have remained hidden had we used more aggregated classifications for field of study and social origin.</jats:p

Untersuchungen zur Regulation der Transkription bei Methanosarcina mazei

To investigate the Methanosarcina mazei regulation of transcription, an in vitro transcription system with purified Methanococcus thermolithotrophicus RNA polymerase and recombinant TBP and TFB from Methanosarcina mazei was established. First, the tfb gene was identified in a genomic lambda-genebank of Methanosarcina mazei S-6, then the gene was sequenced and cloned. Analysis of TBP and TFB amino acid sequences revealed characteristic archaeal features for these proteins. Then TBP and TFB were expressed in E. coli and purified by means of column-chromatography. The functional activity of recombinant TBP and TFB was demonstrated in the in vitro transcription system of Methanococcus thermolithotrophicus. The purified RNA polymerase from Methanosarcina mazei showed no specific activity, therefore the RNA polymerase from Methanococcus thermolithotrophicus was purified for the use in the cell-free transcription system. Analysis of in vitro transcription of the Methanosarcina mazei heat shock genes grpE, dnaK, and dnaJ, which have the in vivo organization 5’-grpE-dnaK-dnaJ-3’, showed only transcription of grpE. The in vitro transcriptional start site of grpE, determined by means of primer extension, is identical with the in vivo transcriptional start site. In transcription of the dnaK gene there is only a weak transcript detectable, which is possibly an unspecific one, and there is no transcription of dnaJ. In vivo there are hints for a monocistronic mode of transcription for these genes, so probably activation for transcription of dnaK and dnaJ is required, which is also suggested by the weakly conserved TATA-box of these genes. A noticeable fivefold direct repeat upstream of dnaK had no influence on in vitro transcription. The gene of the archaeal transcription factor TFE was also cloned, afterwards the protein was expressed in E. coli and purified by means of column-chromatography. Analysis of the amino acid sequence revealed the typical characteristics of archaeal homologues. The functional activity of the recombinant protein was demonstrated in the established cell-free transcription system. It was shown that there is a strong stimulation of transcription when sub-optimal TBP concentrations were used, whereas at optimal TBP concentration only a weak stimulatory effect is detectable. It was not possible to show a clear specific in vitro transcription inhibition for the glnK gene from Methanosarcina mazei by the potential repressor AmtR, because of the inhibitory effect of the protein on transcription of other genes as well, which is probably caused by an unspecific DNA affinity. Nevertheless the inhibitory effect on transcription of glnK is stronger, and it was shown that there is probably a binding of AmtR to a potential binding site 495 bp upstream of the transcriptional start site of the glnK gene. Preincubation of AmtR and TBP/TFB, respectively, with promoter DNA of glnK, followed by in vitro transcription or gel retardation assays showed that there is no specific binding of AmtR to another potential binding site in the TATA-box region. AmtR shifts unaffected by the used DNA the DNA-TBP-TFB complex, and AmtR even can form a DNA-TBP-AmtR complex. So in the presence of DNA there is an interaction between TBP and AmtR, but without DNA, there was no direct interaction detectable. These results indicate a regulatory function of AmtR

Academics’ Attitudes Toward Engaging in Public Discussions: Experimental Evidence on the Impact of Engagement Conditions

Growing demands and expectations on the side of policy makers and the public have changed the conditions for academics’ engagement in public discussions. At the same time, risks related to this engagement for the professional and even private lives of academics have become apparent. Conducting a survey experiment among 4091 tenured professors in Germany, we study how these conditions causally affect academics’ attitudes toward engaging. Consistent with the crowding-out of intrinsic motivation, we find less-positive attitudes when emphasizing demands for engagement by public authorities and public expectations toward science’s societal relevance. Effects are particularly strong among professors endorsing science–society relations. Moreover, effects are similar when highlighting risks associated with engagement, but more pronounced for females and younger professors. Emphasizing public support for academics’ engagement has no discernible effects. We conclude that considering individual incentive structures and safeguarding against negative repercussions may promote academics’ engagement and an adequate representation of the diversity of academics in the public

There’s no such thing as mental retirement: older workers willingly engage in learning

A study shows workers' intrinsic willingness to learn, regardless of employer requirement and financial constraints - by Stephan L. Thomsen, Jens Ruhose and Insa Weilag

Presynaptic Calcium Signalling in Cerebellar Mossy Fibres

Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX)-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1 s affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette