An ancestral core haplotype defines the critical region harbouring the North Carolina macular dystrophy gene (MCDR1)

Autosomal dominant North Carolina macular dystrophy (NCMD) or central areolar pigment epithelial dystrophy (CAPED) is an allelic disorder that maps to an approximately 7.2 cM interval between DNA markers at D6S424 and D6S1671 on 6q14-q16.2. The further refinement of the disease locus has been hindered by the lack of additional recombination events involving the critical region. In this study, we have identified three multigeneration families of German descent who express the NCMD phenotype. Genotyping was carried out with a series of markers spanning approximately 53 cM around the NCMD locus, MCDR1. Genetic linkage between the markers and the disease phenotype in each of the families could be shown. Disease associated haplotypes were constructed and provide evidence for an ancestral founder for the German NCMD families. This haplotype analysis suggests that a 4.0 cM interval flanked by markers at D6S249 and D6S475 harbours the gene causing NCMD, facilitating further positional cloning approaches.     

Learning with video‐based examples – Are you sure you do not need help?

This study investigated help‐seeking activities in a computer‐based environment teaching argumentative skills by videos of argumentative dialogues of teachers who discussed controversy issues in the context of a workshop. Learners, all of them students of educational sciences, solved learning tasks on the presented argumentative dialogues and reflected on their response certitude. Forty‐three students voluntary took part in the study. Two experimental groups varied according to the type of task they solved. Group 1 got adjunct questions, so‐called self‐explanation prompts that elicited elaboration of the video content. Group 2 answered multiple‐choice tasks that assessed the same knowledge. After each task, participants of both groups (a) had to judge the certainty of their response being correct (i.e., the marking of the multiple‐choice task or the written self‐explanations) and (b) were offered to use the help function on demand. Results revealed the relevance of learners' response certitude with respect to their help use. Low response certitude about the correctness of a task solution led to higher help use which was positively related to learning outcome. However, learners' response certitude was unrelated to the actual correctness of their task solution. Type of task had no influence on response certitude, help use or learning outcome.     

Online help-seeking in communities of practice: Modeling the acceptance of conceptual artifacts

Interactive online help systems are considered to be a fruitful supplement to traditional IT helpdesks, which are often overloaded. They often comprise user-generated FAQ collections playing the role of technology-based conceptual artifacts. Two main questions arise: how the conceptual artifacts should be used, and which factors influence their acceptance in a community of practice (CoP). Firstly, this paper offers a theoretical frame and a usage scenario for technology-based conceptual artifacts against the theoretical background of the academic help-seeking and CoP approach. Each of the two approaches is extensively covered by psychological and educational research literature, however their combination is not yet sufficiently investigated. Secondly, the paper proposes a research model explaining the acceptance of conceptual artifacts. The model includes users' expectations toward the artifact, perceived social influence and users' roles in the CoP as predictors of artifact use intention and actual usage. A correlational study conducted in an academic software users' CoP and involving structural equations modeling validates the model, suggesting thus a research line that is worth further pursuing. For educational practice, the study suggests three ways of supporting knowledge sharing in CoPs, i.e. use of technology-based conceptual artifacts, roles and division of labor, and purposeful communication in CoPs.     

Learning argumentation skills through the use of prompts for self-explaining examples.

Learning with self-explaining examples is an effective method in well-structured domains. The authors analyzed this method in teaching the complex skill of argumentation, experimentally comparing 4 conditions (N = 71 student teachers) that differed with respect to whether and how the processing of the examples was supported by self-explanation prompts. They found that examples of argumentation could be successfully used to teach declarative knowledge about argumentation. However, when the skill of argumentation is to be fostered, prompts that direct the learners' attention to the principles of argumentation should be used. The authors demonstrate that learning with self-explaining examples is also a promising method of enhancing skills in ill-structured domains such as argumentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning to teach with worked-out examples: a computer-based learning environment for teachers

Abstract   Learning from worked-out examples has been shown to be very effective in initial cognitive skill acquisition. In order to fully exploit the potential of example-based learning, teachers should, however, know how to effectively employ such examples in classroom instruction. Therefore, we have designed a computer-based learning environment in which mathematics and science teachers learn how to effectively employ worked-out examples. The learning environment was developed according to approved design criteria. The topics that are addressed in the learning environment were chosen in response to the results of a needs assessment that analysed schoolbooks and classroom videos, and took interviews with teachers into account. In experiments as well as in several teacher trainings on example-based learning, the computer-based learning environment was evaluated and improved accordingly. On a more general level, our research and development project showed that a computer-based learning programme could be a sensible tool that supports follow-up work in teacher training contexts.     

Computer-supported example-based learning: When instructional explanations reduce self-explanations

We investigated whether the findings from worked-out example research on the effects of self-explanation prompts and on instructional explanations can be generalized to other example types – in this case: solved example problems. Whereas worked-out examples consist of a problem formulation, solution steps, and the final solution, solved example problems merely provide the problem formulation and the solution. We employed a first module of a computer-based environment for student teachers presenting solved example problems from which they learned how to select and to design worked-out examples for high school students. The participants (47 student teachers for German low- and medium-track schools and 33 student teachers for high-track schools) were randomly assigned to the cells of our 2 × 2 design (with vs. without self-explanation prompts; with vs. without instructional explanations). The effects of the different program versions on objective and subjective learning outcomes, on the perceived helpfulness of the program, and on the learning time were analyzed. As learning process data, the written and spoken self-explanations were assessed. The following main results were obtained: Particularly self-explanation prompts had favorable effects on learning outcomes, whereas instructional explanations can reduce the student teacher’s self-explanation activities and thereby the learning outcomes. Whereas “objectively” the most favorable learning outcomes were obtained when only self-explanation prompts were employed, the student teachers perceived their learning outcome best when only instructional explanations were provided. It can be concluded that the status of self-explanation prompts and of instructional explanations is comparable irrespective of the example type presented for learning.     

Soluble interleukin-1 receptor antagonist serum levels in smokers and nonsmokers with Graves' ophthalmopathy undergoing orbital radiotherapy

Interleukin-1 (IL-1) plays an important role in the pathogenesis of Graves' ophthalmopathy (GO). Impaired antagonism of the proinflammatory cytokine IL-1 by the naturally occurring IL-1 receptor antagonist (IL-1RA) has been implicated in the initiation and perpetuation of various autoimmune diseases and may play a role in the evolution of GO. Cigarette smoking appears to adversely affect the course of GO. We have evaluated the course of IL-1 alpha, IL-1 beta, and soluble IL-1RA (sIL-1RA) serum levels in smokers and nonsmokers with GO undergoing orbital radiotherapy (OR). We prospectively studied the eye status of 27 randomly selected patients (mean age 47.3 +/- 11.0 yr; 20 females; 18 smokers) with active, moderately severe GO before and 3 and 6 months following OR, respectively. None had received any previous treatment for GO, and all patients were kept euthyroid on carbimazole. Serum concentrations of IL-1 alpha, IL-1 beta, and sIL-1RA were measured using highly sensitive enzyme linked immunosorbent assay systems. Baseline sIL-1RA levels were negatively correlated with the number of cigarettes smoked before and following OR (P < 0.0001). Patients with no or minor therapeutic response to OR (n = 8), all of whom were smokers, revealed mean baseline sIL-1RA levels of 114 +/- 85 pg/mL, which increased to 172 +/- 103 pg/mL at 3 months and 149 +/- 96 pg/mL at 6 months after initiation of OR, respectively. By contrast, patients with a good clinical response (n = 19, 9 nonsmokers), revealed significantly higher baseline sIL-1RA levels at 294 +/- 148 pg/mL (P = 0.004), which increased to 845 +/- 668 pg/mL at 3 months (P = 0.01) and 634 +/- 337 pg/mL at 6 months (P < 0.001), respectively, following initiation of OR. Serum concentrations of IL-1 alpha IL-1 beta were below 3.9 pg/mL in all patients with GO who were studied, and were not correlated with gender, age, smoking status, clinical course, or outcome. Low baseline levels and impaired surge of sIL-1RA serum levels following OR were strongly correlated with smoking status and a less favorable therapeutic outcome in patients with active, moderately severe GO. Measurement of sIL-1RA may contribute to predict the therapeutic response to OR in patients with active, moderately severe GO. Strategies designed to raise local or systemic concentrations of sIL-1RA may be of benefit to patients with GO.     

Endocrinologic and metabolic complications of Alagille syndrome]

BACKGROUND: First language acquisition depends on intermodal perception, especially auditive, tactile-kinesthetic, and partly visual in addition to sensomotoric integration. The influence of the vestibular function for a physiological language development is still unknown. PATIENT: A case history of a child with bilateral aplasia of all semicircular canals, normacusis in the right ear, and severe sensorineural hearing loss in the left (hearing aid supplied), without mental deficiency, allows us to draw initial conclusions. RESULTS: Logopedic diagnostics revealed only a mild articulation disorder (interdental sigmatism, inconstant gammacism) as a possible consequence of recurrent middle ear effusions since early childhood. Language development diagnostics did not demonstrate any significant norm deviation. CONCLUSIONS: In contrast to the statomotoric disorder, no evidence for a specific language impairment was found. Our report elucidates the importance of a selected diagnostic imaging (spiral CT and MIP MRI) in the phoniatric-ped-audiological field.