Structural and dynamic properties of linker histone H1 binding to DNA

Found in all eukaryotic cells, linker histones H1 are known to bind to and rearrange nucleosomal linker DNA. In vitro, the fundamental nature of H1∕DNA interactions has attracted wide interest among research communities-from biologists to physicists. Hence, H1∕DNA binding processes and structural and dynamical information about these self-assemblies are of broad importance. Targeting a quantitative understanding of H1 induced DNA compaction mechanisms, our strategy is based on using small-angle x-ray microdiffraction in combination with microfluidics. The usage of microfluidic hydrodynamic focusing devices facilitates a microscale control of these self-assembly processes, which cannot be achieved using conventional bulk setups. In addition, the method enables time-resolved access to structure formation in situ, in particular, to transient intermediate states. The observed time dependent structure evolution shows that the H1∕DNA interaction can be described as a two-step process: an initial unspecific binding of H1 to DNA is followed by a rearrangement of molecules within the formed assemblies. The second step is most likely induced by interactions between the DNA and the H1's charged side chains. This leads to an increase in lattice spacing within the DNA∕protein assembly and induces a decrease in the correlation length of the mesophases, probably due to a local bending of the DNA.     

Bildungsexpansion und Bildungsbeteiligung

Die vorliegende Untersuchung ist ein Beitrag, die Frage zu kl?ren, warum in der westdeutschen Nachkriegszeit immer mehr Schulpflichtige nach Abschluss der Grundschule das Gymnasium besuchen. Ausgehend von einem entscheidungstheoretischen Modell der subjektiven Werterwartung werden Mechanismen der elterlichen Bildungsentscheidung aufgezeigt. Dabei wird davon ausgegangen, dass sowohl zunehmende Bildungsmotivationen als auch Ver?nderungen in der subjektiven Bewertung von Kosten und Nutzen für eine h?here Bildung wichtige Voraussetzungen für die zunehmende Bildungsbeteiligung, aber auch Folgen der Bildungsexpansion waren. Die empirischen Analysen für drei Zeitpunkte in den 60er, 70er und 80er Jahren best?tigen diese Annahmen weitgehend. Ebenso wurde empirisch belegt, welch wichtige Rolle neben den Bildungsintentionen von Eltern und dem vorhergehenden Bildungsverlauf ihrer Kinder auch strukturelle Momente der Bildungsexpansion und ihre Eigendynamik beim tats?chlichen Bildungsübergang spielen. Schlie?lich gibt es Hinweise dafür, dass die Persistenz klassenspezifischer Bildungsungleichheiten auf einer konstanten Balance von Nutzen und Kosten zwischen den sozialen Klassen basiert.     

Davvin and Sámás ‐‐ a Saami Language Project: From a ‘condescending’ thought to a real foundation

Abstract

The creation of a written language in a small linguistic society based on existing oral dialects can be a very intriguing and delicate matter. It demands a sense of compromise from the speakers of the language and a readiness and understanding from the surrounding ‘host’ society. This article describes the development of a Nordic co‐production in the Saami language.     

Follow-up of a preschool epidemiological sample: cross-age continuities and predictions of later adjustment with internalizing and externalizing dimensions of behavior

The continuity of behavioral adjustment from preschool through elementary school and junior high school years was examined. 541 children aged 9-15 years from a preschool epidemiological study were relocated and behavior checklist data obtained. Analyses focused on the relationship between internalizing and externalizing behavior dimensions from the preschool to follow-up periods. It was found that preschool externalizing symptoms were positively correlated with later externalizing and internalizing symptoms in the entire sample. Preschool internalizing symptoms, however, were predictive of later internalizing symptoms only for 2-year-old girls and 5- and 6-year-old boys. Similar results were obtained for clinically disturbed preschoolers. Results are consistent with previous findings regarding the longitudinal continuity of externalizing behavior but are at odds with reports of equal or greater stability of internalizing behavior. Given the magnitude of obtained correlations, even when significant, the results support the view that discontinuity rather than continuity in behavioral adjustment from preschool to later ages is the rule. The importance of examining other mediating variables in the prediction of behavioral adjustment and the need for models of development that encompass both stability and change are discussed.     

Analgesics use in competitive triathletes: its relationship to doping and on predicting its usage

The two major objectives of this study were (i) to assess variables that predict the use of analgesics in competitive athletes and (ii) to test whether the use of analgesics is associated with the use of doping. A questionnaire primarily addressing the use of analgesics and doping was distributed among 2,997 triathletes. Binary logistic regression analysis was performed to predict the use of analgesics. Moreover, the randomised response technique (RRT) was used to estimate the prevalence of doping in order to assess whether users of analgesics have a higher potential risk for doping than non-users. Statistical power analyses were performed to determine sample size. The bootstrap method was used to assess the statistical significance of the prevalence difference for doping between users and non-users of analgesics. Four variables from a pool of 16 variables were identified that predict the use of analgesics. These were: “version of questionnaire (English)”, “gender (female)”, “behaviour in case of pain (continue training)”, and “hours of training per week (>12 h/week)”. The 12-month prevalence estimate for the use of doping substances (overall estimate 13.0%) was significantly higher in athletes that used analgesics (20.4%) than in those athletes who did not use analgesics (12.4%). The results of this study revealed that athletes who use analgesics prior to competition may be especially prone to using doping substances. The predictors of analgesic use found in the study may be of importance to prepare education material and prevention models against the misuse of drugs in athletes.     

The impact of physical growth and relative age effect on assessment in physical education

Physical education (PE) is perhaps the school subject most likely to produce relative age effects (RAE). Like in sports, physical maturity gives students an advantage in PE, which might well be mistaken for superior ability. The aim of the present study is to investigate the extent to which physical growth, measured as height, and RAE reflect the assessment in Norwegian PE. Furthermore, we wanted to examine whether there is any gender differences in the assessment in PE as a function of physical growth and RAE. The participants (n?=?2978) were pupils in the last three years of secondary school (13–16 years old). A custom-made questionnaire was designed to collect the necessary data. The correlations between height and mark in PE for boys in 8th, 9th, and 10th grades are respectively r?=?0.14, r?=?0.32, and r?=?0.29. For girls, the correlations are r?=?0.11, r?=?0.33, and r?=?0.21. All correlations are significant (p?<?.05). The number of pupils achieving top marks was 114 in the first half of the year, whereas it was 65 in the second half of the year. The present study showed that physical growth has an impact on the pupils’ PE attainment. The physical growth is of course also mediated by the pupils’ age. RAEs were found in PE attainments also in the Norwegian school system for both genders, despite all the intentions expressed in the PE curriculum.     

Measuring social capital through network analysis and its influence on individual performance

Studies of social networks highlight the importance of network structure or structural properties of a given network and its impact on performance outcome. One of the important properties of this network structure is referred to as social capital, which is the network of contacts and the associated values attached to these networks of contacts. This study provides empirical evidence of the influence of social capital and performance within the context of academic collaboration (coauthorship) and suggests that the collaborative process involves social capital embedded within relationships and network structures among direct coauthors. Association between scholars' social capital and their citation-based performance measures is examined. To overcome the limitations of traditional social network metrics for measuring the influence of scholars' social capital within coauthorship networks, the traditional social network metrics is extended by proposing two new measures, of which one is non-weighted (the power–diversity index) and the other (power–tie–diversity index) is weighted by the number of collaboration instances. The Spearman's correlation rank test is used to examine the association between scholars' social capital measures and their citation-based performance. Results suggest that research performance of authors is positively correlated with their social capital measures. The power–diversity index and power–tie–diversity index serve as indicators of power and influence of an individual's ability to control communication and information.     

Halite – A new calibration material for microdrilling resistance measurements

This paper aims at proposing a new calibration material for microdrilling resistance measurements. Microdrilling resistance is a microdestructive method mainly used in built heritage in order to determine the strength profile in depth. This method is suitable to detect changes in the material cohesion, either due to a different state of preservation or to the action of a consolidant. Calibration materials are often used in microdrilling measurements in order to characterise the drill bit initial value and to correct the variations existing within the initial values of a set of drill bits. Calibration materials are also useful to detect the wear effect on a drill bit due to an abrasive stone. Moreover, such materials can be used for comparing results obtained with different microdrilling machines. In this work, halite was chosen to be tested as a calibration material due to its properties, as low hardness and isotropy. Halite single crystals and halite salt stone from different provenances were tested in order to evaluate the suitability of this material to the requests of a calibration material for microdrilling resistance applications, as for instance being homogeneous, non-abrasive, sensitive and available worldwide. Experimental results show that halite from different provenances is very homogeneous, especially in the crystalline form. This form of halite is slightly more expensive than stone halite; however its costs are comparable to ARS and significantly lower than Macor (other calibration materials commonly used for microdrilling resistance measurements). Due to the advantages of halite for calibration purposes, this material should be further tested by other authors in order to validate our conclusions.