Non-parametric adaptive locally asymptotically optimum detection in additive noise

In this paper, a new approach to non-parametric signal detection with independent noise sampling is presented. The present approach is based on the locally asymptotically optimum (LAO) methodology, which is valid for vanishingly small signals and very large sample sizes, and on semi-parametric statistics. Its unique feature and essential difference from other techniques is that LAO non-parametric detectors are optimum according to the Neyman-Pearson criterion by being asymptotically uniformly most powerful at false alarm level α (AUMP (α)) and adaptive in the sense that no loss in Fisher's information number is incurred when the underlying noise process is no longer parametrically defined. Accordingly, they are robust against deviations from the postulated noise model and, unlike other non-parametric detectors, are distribution-free under both hypotheses H₀ (“noise only present”) and H₁ (“signal and noise present”). Non-parametric LAO detectors are derived from an asymptotic stochastic expansion of the log-likelihood ratio for coherent and narrowband incoherent “on-off” signals. Moreover, under the present framework it is shown that, in direct contrast to already known results, the non-parametric sign detector is AUMP (α) and adaptive even for non-constant signal samples.     

A Conceptual Characterization of Online Videos Explaining Natural Selection

Educational videos on the Internet comprise a vast and highly diverse source of information. Online search engines facilitate access to numerous videos claiming to explain natural selection, but little is known about the degree to which the video content match key evolutionary content identified as important in evolution education research. In this study, we therefore analyzed the content of 60 videos accessed through the Internet, using a criteria catalog with 38 operationalized variables derived from research literature. The variables were sorted into four categories: (a) key concepts (e.g. limited resources and inherited variation), (b) threshold concepts (abstract concepts with a transforming and integrative function), (c) misconceptions (e.g. that evolution is driven by need), and (d) organismal context (e.g. animal or plant). The results indicate that some concepts are frequently communicated, and certain taxa are commonly used to illustrate concepts, while others are seldom included. In addition, evolutionary phenomena at small temporal and spatial scales, such as subcellular processes, are rarely covered. Rather, the focus is on population-level events over time scales spanning years or longer. This is consistent with an observed lack of explanations regarding how randomly occurring mutations provide the basis for variation (and thus natural selection). The findings imply, among other things, that some components of natural selection warrant far more attention in biology teaching and science education research.     

Guidance in inquiry-based instruction – an attempt to disentangle a manifold construct

Inquiry-based instruction is an important teaching strategy in science education that can be implemented to achieve different learning goals (e.g. the learning of science content or of inquiry skills and strategies). Inquiry-based instruction is often combined with guidance attempting to assist students to effectively engage in inquiry activities and, through this engagement, reach the intended goals. In recent research, the type and amount of guidance needed to foster student’s learninghas received considerable attention. One challenge in interpreting the results of this line of research is the manifold meanings of the term ‘guidance’ and its implementation in inquiry-based instruction. Moreover, the effectiveness of a particular type and amount of guidance may also depend on the learning goal that is to be achieved. In this paper, we draw on existing research and theoretical considerations in attempting to disentangle three major dimensions in which the implementation of guidance may vary: (a) the degree of autonomy, (b) the degree of conceptual information, and (c) the cognitive domain of guidance. We discuss how these dimensions can be used to capture and systemise fidings of existing studies as well as to infer desiderata for further research on the role of guidance in inquiry-based instruction.     

Teaching evaluation: antecedents of teachers’ perceived usefulness of follow-up sessions and perceived stress related to the evaluation process

This study examines teaching evaluation based on student feedback which is intended to contribute to teachers’ professional development. Although studies have highlighted that teaching evaluation is a potential source of professional development and that follow-up sessions are crucial to this benefit, little attention has been paid to the usefulness of follow-up sessions as perceived by the teachers involved. Based on 217 teacher responses and analysis done with Structural Equation Modelling, this article provides additional insight into teaching evaluation by investigating possible antecedents for teachers’ perceived usefulness of follow-up sessions and for evaluation-related stress. Our results indicate that the perceived developmental purposes of teaching evaluation, recognition of the person conducting follow-up sessions and perceived clear communication from leaders are positively related to teachers’ perceived usefulness of follow-up sessions. Higher levels of perceived control purposes are related to higher levels of reported stress among the evaluated teachers.     

Differentiating Different Types of Cognitive Load: a Comparison of Different Measures

Recent studies about learning and instruction use cognitive load measurement to pay attention to the human cognitive resources and to the consumption of these resources during the learning process. In order to validate different measures of cognitive load for different cognitive load factors, the present study compares three different methods of objective cognitive load measurement and one subjective method. An experimental three-group design (N = 78) was used, with exposure to seductive details (extraneous cognitive load factor), mental animation tasks (germane cognitive load factor), or the basic learning instruction (control group). Cognitive load was measured by the rhythm method (Park and Brünken 2015), the index of cognitive activity (ICA) (Marshall 2007), and the subjective ratings of mental effort and task difficulty (Paas 1992). Eye-tracking data were used to analyze the attention allocation and as an indicator for cognitive activity. The results show a significantly higher cognitive load for the mental animation group in contrast to the control and the seductive detail group, indicated by rhythm method and subjective ratings, as well as a higher cognitive activity, indicated by eye tracking. Furthermore, the mental animation group shows significantly higher comprehension performance in contrast to the seductive detail group and significantly higher transfer performance in contrast to the control group. The ICA values showed no significant differences in cognitive load. The results provide evidence for the benefits of combining eye-tracking analysis and the results of cognitive load ratings or secondary task performance for a direct and continuous cognitive load assessment and for a differentiating access to the single cognitive load factors.     

Quantification of wall surface heterogeneity and its influence on species diversity at medieval castles – implications for the environmentally friendly preservation of cultural heritage

Historic buildings are important for cultural history and provide a variety of habitats for animals and plants. Especially structural heterogeneity of wall surfaces is perceived to support biological diversity. Nevertheless, in traditional approaches goals of biodiversity preservation and monument restoration are perceived to interfere and to be mutually exclusive. As a consequence, priority is often given to constructional restoration accepting the loss of local populations and biodiversity. At walls of medieval castles, including an experimental restoration project where conventional and less intensive restoration techniques were applied, we relate species composition and richness to wall properties. Especially wall surface structure is quantified using a novel approach. The study focuses on lichens, mosses and vascular plants. Boosted regression tree analyses and non-metric multidimensional scaling techniques are applied to detect the influence of abiotic site conditions on biodiversity. We find species richness to be promoted by wall surface heterogeneity. However, species composition is more affected by restoration approaches than species richness. Lichen composition varies considerably while vascular plants and mosses are less affected by wall properties. We suggest strategies that are combining both societal targets, the preservation of historic monuments and of species diversity. Careful restoration is capable of supporting both, the maintenance of cultural heritage and of rare and unique anthropogenic habitats. Wall surface heterogeneity needs to be witnessed for both aspects as it affects both species composition as well as the effectiveness of cleaning methods.     

Informationen des Deutschen Olympischen Sportbunds (DOSB)

DOSB-Informationen

Informationen des Deutschen Olympischen Sportbunds (DOSB)     

4D spinless topological insulator in a periodic electric circuit

According to the mathematical classification of topological band structures, there exist a number of fascinating topological states in dimensions larger than three with exotic boundary phenomena and interesting topological responses. While these topological states are not accessible in condensed matter systems, recent works have shown that synthetic systems, such as photonic crystals or electric circuits, can realize higher-dimensional band structures. Here, we argue that, because of its symmetry properties, the 4D spinless topological insulator is particularly well suited for implementation in these synthetic systems. We explicitly construct a 2D electric circuit lattice, whose resonance frequency spectrum simulates the 4D spinless topological insulator. We perform detailed numerical calculations of the circuit lattice and show that the resonance frequency spectrum exhibits pairs of 3D Weyl boundary states, a hallmark of the nontrivial topology. These pairs of 3D Weyl states with the same chirality are protected by classical time-reversal symmetry that squares to +1, which is inherent in the proposed circuit lattice. We also discuss how the simulated 4D topological band structure can be observed in experiments.     

Linking Survey and Media Content Data: Opportunities,Considerations, and Pitfalls

In media effects research a fundamental choice is often made between (field) experiments or observational studies that rely on survey data in combination with data about the information environment or media coverage. Such studies linking survey data and media content data are often dubbed “linkage studies.” On the one hand, such designs are the state of the art in our field and on the other hand, they come with a long list of challenges and choices. This article reviews the rationales for linkage studies, outlines different types of linkage studies, reviews the state-of-the-art in this area, discusses which survey and content items to use in an analysis, reviews different types of analyses, outlines considerations for alternative specifications, and provides a step-by-step example.     

Predicting Students’ Skills in the Context of Scientific Inquiry with Cognitive,Motivational, and Sociodemographic Variables

Research on predictors of achievement in science is often targeted on more traditional content-based assessments and single student characteristics. At the same time, the development of skills in the field of scientific inquiry constitutes a focal point of interest for science education. Against this background, the purpose of this study was to investigate to which extent multiple student characteristics contribute to skills of scientific inquiry. Based on a theoretical framework describing nine epistemological acts, we constructed and administered a multiple-choice test that assesses these skills in lower and upper secondary school level (n?=?780). The test items contained problem-solving situations that occur during chemical investigations in school and had to be solved by choosing an appropriate inquiry procedure. We collected further data on 12 cognitive, motivational, and sociodemographic variables such as conceptual knowledge, enjoyment of chemistry, or language spoken at home. Plausible values were drawn to quantify students’ inquiry skills. The results show that students’ characteristics predict their inquiry skills to a large extent (55%), whereas 9 out of 12 variables contribute significantly on a multivariate level. The influence of sociodemographic traits such as gender or the social background becomes non-significant after controlling for cognitive and motivational variables. Furthermore, the performance advance of students from upper secondary school level can be explained by controlling for cognitive covariates. We discuss our findings with regard to curricular aspects and raise the question whether the inquiry skills can be considered as an autonomous trait in science education research.