The structure of academic self-concept. A methodological review and empirical illustration of central models

The structure of academic self-concept (ASC) is assumed to be multidimensional and hierarchical. This methodological review considers the most central models depicting the structure of ASC: a higher-order factor model, the Marsh/Shavelson model, the nested Marsh/Shavelson model, a bifactor representation based on exploratory structural equation modeling, and a first-order factor model. We elaborate on how these models represent the theoretical assumptions on the structure of ASC and outline their inherent psychometric properties. We analyzed these models using a data set of German 10th-grade students (N = 1,232) including a wide range of domain-specific ASCs as well as general ASC. The correlations among ASCs and between ASCs and academic achievement varied depending on the structural model used. We conclude with discussing recommendations for research purposes and advantages and limitations of each ASC model. Our approach may also guide research on other affective or motivational constructs (e.g., academic anxiety or interest). (DIPF/Orig.

Chemiker machen Karriere. Und Chemikerinnen? Eine Annäherung an die Karrierebilder im Fachdiskurs der Chemie

"Ausgehend von der These, dass die jeweilige wissenschaftliche Fachkultur den Rahmen für Berufskarrieren bildet, wurde der spezifische Fachdiskurs über Karrieren von Chemiker/- innen im Fachmagazin Nachrichten aus der Chemie untersucht. Die Leitfrage lautete: Werden Karrieren von Chemiker/-innen in der Community geschlechterdifferent präsentiert? Falls ja, worin unterscheiden sie sich? Die Analyse der Nachrichten zeigt, dass die Karriere von Chemiker/-innen einem mehrjährigen Entwicklungsprozess folgt. Er wird von einer zeitlichen Abfolge bestimmter Karrierestationen determiniert, die in der Regel mit einem Prestige- oder Statusgewinn in der Community einhergehen. Große fachliche und institutionelle Hürden zu überwinden, wird als notwendiges Merkmal einer erfolgreichen Karriere gewertet. Festhalten lässt sich Folgendes: 1. Karrieren von Chemiker/-innen folgen einem hindernisreichen Weg, scheinbar ohne Privatleben und ohne Bezug zum (sozialen) Geschlecht der Person. 2. Chemikerinnen können beruflich erfolgreich in der Chemie sein. Sie werden jedoch präsentiert als Chemiker, bleiben als Chemikerin eher unsichtbar. 3. In der Regel wird Geschlecht nicht thematisiert - wenn doch, dann eher als Hemmnis für eine Karriere von Chemikerinnen." (Autorenreferat)"This article aims to analyze a specific discourse on the careers of female and male chemists in the journal Nachrichten aus der Chemie. The article is based on the assumption that the scientific culture in the field of chemistry frames these careers. Are chemists' careers presented in a gender-sensitive way? And if so, how does this presentation differ? Based on content analyses of the Nachrichten, the study shows that the chemists' careers follow a multi-annual development process which is determined by a chronology of identified career steps. These generally go hand in hand with an increase in prestige or status in the community. A key characteristic of a successful career in chemistry is having to overcome difficulties at every stage in one's career. In conclusion, it is apparent that (1) the careers of male and female chemists follow a career path which is full of obstacles and apparently leaves no space for a private life, without regard to sex and gender roles; (2) female chemists do climb the career ladder, but these women are presented as male/ masculine chemists. (3) The journal does not generally refer to sex and gender; where gender does play a role, it is presented as an obstacle which women have to overcome." (author's abstract

Outbreak of leptospirosis among triathlon participants in Germany, 2006

<p>Abstract</p> <p>Background</p> <p>In August 2006, a case of leptospirosis occurred in an athlete after a triathlon held around Heidelberg and in the Neckar river. In order to study a possible outbreak and to determine risk factors for infection an epidemiological investigation was performed.</p> <p>Methods</p> <p>Participants of the triathlon were contacted by e-mail and were asked to fill out a standardized questionnaire. In addition, they were asked to supply a serum sample for laboratory diagnosis of leptospirosis. A confirmed case patient was defined as a clinical case (i.e. fever and at least one additional symptom suggestive for leptospirosis) with at least two of the following tests positive: ELISA IgM, latex agglutination testing, or microscopic agglutination testing. Rainfall and temperature records were obtained.</p> <p>Results</p> <p>A total of 142 of 507 triathletes were contacted; among these, five confirmed leptospirosis cases were found. Open wounds were identified as the only significant risk factor for illness (p = 0.02). Heavy rains that preceded the swimming event likely increased leptospiral contamination of the Neckar River.</p> <p>Discussion</p> <p>This is the first outbreak of leptospirosis related to a competitive sports event in Germany. Among people with contact to freshwater, the risk of contracting leptospirosis should be considered by health care providers also in temperate countries, particularly in the summer after heavy rains.</p

Characterization of Total RNA, CD44, FASN, and PTEN mRNAs from Extracellular Vesicles as Biomarkers in Gastric Cancer Patients

In-depth characterization has introduced new molecular subtypes of gastric cancer (GC). To identify these, new approaches and techniques are required. Liquid biopsies are trendsetting and provide an easy and feasible method to identify and to monitor GC patients. In a prospective cohort of 87 GC patients, extracellular vesicles (EVs) were isolated from 250 µL of plasma. The total RNA was isolated with TRIZOL. The total RNA amount and the relative mRNA levels of CD44, PTEN, and FASN were measured by qRT-PCR. The isolation of EVs and their contained mRNA was possible in all 87 samples investigated. The relative mRNA levels of PTEN were higher in patients already treated by chemotherapy than in chemo-naïve patients. In patients who had undergone neoadjuvant chemotherapy followed by gastrectomy, a decrease in the total RNA amount was observed after neoadjuvant chemotherapy and gastrectomy, while FASN and CD44 mRNA levels decreased only after gastrectomy. The amount of RNA and the relative mRNA levels of FASN and CD44 in EVs were affected more significantly by chemotherapy and gastrectomy than by chemotherapy alone. Therefore, they are a potential biomarker for monitoring treatment response. Future analyses are needed to identify GC-specific key RNAs in EVs, which could be used for the diagnosis of gastric cancer patients in order to determine their molecular subtype and to accompany the therapeutic response

Dimerization of melanocortin 4 receptor controls puberty onset and body size polymorphism

Xiphophorus fish exhibit a clear phenotypic polymorphism in puberty onset and reproductive strategies of males. In X. nigrensis and X. multilineatus, puberty onset is genetically determined and linked to a melanocortin 4 receptor (Mc4r) polymorphism of wild-type and mutant alleles on the sex chromosomes. We hypothesized that Mc4r mutant alleles act on wild-type alleles by a dominant negative effect through receptor dimerization, leading to differential intracellular signaling and effector gene activation. Depending on signaling strength, the onset of puberty either occurs early or is delayed. Here, we show by Förster Resonance Energy Transfer (FRET) that wild-type Xiphophorus Mc4r monomers can form homodimers, but also heterodimers with mutant receptors resulting in compromised signaling which explains the reduced Mc4r signaling in large males. Thus, hetero- vs. homo- dimerization seems to be the key molecular mechanism for the polymorphism in puberty onset and body size in male fish

Between Metabolite Relationships: an essential aspect of metabolic change

Not only the levels of individual metabolites, but also the relations between the levels of different metabolites may indicate (experimentally induced) changes in a biological system. Component analysis methods in current ‘standard’ use for metabolomics, such as Principal Component Analysis (PCA), do not focus on changes in these relations. We therefore propose the concept of ‘Between Metabolite Relationships’ (BMRs): common changes in the covariance (or correlation) between all metabolites in an organism. Such structural changes may indicate metabolic change brought about by experimental manipulation but which are lost with standard data analysis methods. These BMRs can be analysed by the INdividual Differences SCALing (INDSCAL) method. First the BMR quantification is described and subsequently the INDSCAL method. Finally, two studies illustrate the power and the applicability of BMRs in metabolomics. The first study is about the induced plant response of cabbage to herbivory, of which BMRs are a considerable part. In the second study—a human nutritional intervention study of green tea extract—standard data analysis tools did not reveal any metabolic change, although the BMRs were considerably affected. The presented results show that BMRs can be easily implemented in a wide variety of metabolomic studies. They provide a new source of information to describe biological systems in a way that fits flawlessly into the next generation of systems biology questions, dealing with personalized responses

Acute and medium term effects of a 10-week running intervention on mood state in apprentices

Exercise and physical activity have proven benefits for physical and psychological well-being. However, it is not clear if healthy young adults can enhance mood in everyday life through regular exercise. Earlier studies mainly showed positive effects of acute exercise and exercise programs on psychological well-being in children, older people and in clinical populations. Few studies controlled participants' physical activity in daily life, performed besides the exercise program, which can impact results. In addition the transition from mood enhancement induced by acute exercise to medium or long-term effects due to regular exercise is not yet determined. The purpose of this pilot study was to examine the acute effects of an aerobic running training on mood and trends in medium term changes of mood in everyday life of young adults. We conducted a 10-week aerobic endurance training with frequent mood assessments and continuous activity monitoring. 23 apprentices, separated into experimental and control group, were monitored over 12 weeks. To control the effectiveness of the aerobic exercise program, participants completed a progressive treadmill test pre and post the intervention period. The three basic mood dimensions energetic arousal, valence and calmness were assessed via electronic diaries. Participants had to rate their mood state frequently on 3 days a week at five times of measurement within 12 weeks. Participants' physical activity was assessed with accelerometers. All mood dimensions increased immediately after acute endurance exercise but results were not significant. The highest acute mood change could be observed in valence (p = 0.07; η(2) = 0.27). However, no medium term effects in mood states could be observed after a few weeks of endurance training. Future studies should focus on the interaction between acute and medium term effects of exercise training on mood. The decreasing compliance over the course of the study requires the development of strategies to maintain compliance over longer periods

Neutral tritium gas reduction in the KATRIN differential pumping sections

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to measure the effective electron anti-neutrino mass with an unprecedented sensitivity of $0.2\,\mathrm{eV}/\mathrm{c}^2$, using $\beta$-electrons from tritium decay. The electrons are guided magnetically by a system of superconducting magnets through a vacuum beamline from the windowless gaseous tritium source through differential and cryogenic pumping sections to a high resolution spectrometer and a segmented silicon pin detector. At the same time tritium gas has to be prevented from entering the spectrometer. Therefore, the pumping sections have to reduce the tritium flow by more than 14 orders of magnitude. This paper describes the measurement of the reduction factor of the differential pumping section performed with high purity tritium gas during the first measurement campaigns of the KATRIN experiment. The reduction factor results are compared with previously performed simulations, as well as the stringent requirements of the KATRIN experiment.Comment: 19 pages, 4 figures, submitted to Vacuu