Magnetic orientation of the Common Toad: establishing an arena approach for adult anurans

<p>Abstract</p> <p>Background</p> <p>Magnetic orientation is a taxonomically widespread phenomenon in the animal kingdom, but has been little studied in anuran amphibians. We collected Common Toads (<it>Bufo bufo</it>) during their migration towards their spawning pond and tested them shortly after displacement for possible magnetic orientation in arena experiments. Animals were tested in two different set-ups, in the geomagnetic field and in a reversed magnetic field. To the best of our knowledge, this is the first study testing orientation of adult anurans with a controlled magnetic field of a known strength and alignment.</p> <p>Results</p> <p>After displacement, toads oriented themselves unimodally under the geomagnetic field, following their former migration direction (d-axis). When the magnetic field was reversed, the distribution of bearings changed from a unimodal to a bimodal pattern, but still along the d-axis. The clustering of bearings was only significant after the toads reached the outer circle, 60.5 cm from their starting point. At a virtual inner circle (diameter 39 cm) and at the start of the experiment, orientation of toads did not show any significant pattern.</p> <p>Conclusions</p> <p>The experimental set-up used in our study is suitable to test orientation behaviour of the Common Toad. We speculate that toads had not enough time to relocate their position on an internal map. Hence, they followed their former migration direction. Bimodality in orientation when exposed to the reversed magnetic field could be the result of a cue conflict, between magnetic and possibly celestial cues. For maintaining their migration direction toads use, at least partly, the geomagnetic field as a reference system.</p

Im Profil

Der Profil-Begriff findet in den Sozialwissenschaften, wenn überhaupt, nur sehr einseitige Anwendung zur tendenziell statischen Darstellung von individueller Komplexität. In dieser tradierten Form hielten Profile auch Einzug auf allen frühen Kommunikationsplattformen des Internet – als demographisches Infoblatt mit Foto, das ein körperlich abwesendes Individuum im Cyberspace repräsentiert. Die Evolution des Web 2.0 hat nun aber in den letzten Jahren Entwicklungen mit sich gebracht, die das Phänomen des Profils praktisch so sehr verändern, dass es nur mehr mit einer entsprechenden theoretischen Neubestimmung des Begriffs erfassbar bleiben kann. Die Arbeit zeigt am Beispiel des sozialen Netzwerks Facebook, dass nur eine starke Dynamisierung und kommunikationswissenschaftliche Fundierung das Konzept des Profils in die Lage versetzen kann, dem Sein und Werden im Web 2.0, das die kommunikativen Handlungsräume von immer mehr Menschen erweitert, auf die Spur zu kommen.Within the discourse of the social sciences, the concept of profile is put to its intended use mainly to statically reconstruct and visualize the inner complexity of individuals. Such – as sociodemographic info sheet including a personal image – profiles got implemented in all social media sites of the World Wide Web at an early stage, to represent physically absent individuals within the realm of cyberspace. In the meantime, the evolution of the so called Web 2.0 changed the practical potentials and capabilities of profiles in a manner, that only a theoretical redefinition of the concept will be able to put it to a an appropriate analytical use again. Based on the illustrative material of the social network Facebook, this thesis wants to demonstrate, that only a strong dynamization and a new foundation in terms of communication science will enable the concept of profile, to adequately describe the dynamic interactions of so many individuals, who already use the options of Web 2.0 to extend their social space

Advice on comparing two independent samples of circular data in biology

LL is supported by the Austrian Science Fund (FWF, Grant Number: P32586). EPM receives funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No 948728). This research was funded in whole, or in part, by the Austrian Science Fund (FWF) P32586.Many biological variables are recorded on a circular scale and therefore need different statistical treatment. A common question that is asked of such circular data involves comparison between two groups: Are the populations from which the two samples are drawn differently distributed around the circle? We compared 18 tests for such situations (by simulation) in terms of both abilities to control Type-I error rate near the nominal value, and statistical power. We found that only eight tests offered good control of Type-I error in all our simulated situations. Of these eight, we were able to identify the Watson’s U2 test and a MANOVA approach, based on trigonometric functions of the data, as offering the best power in the overwhelming majority of our test circumstances. There was often little to choose between these tests in terms of power, and no situation where either of the remaining six tests offered substantially better power than either of these. Hence, we recommend the routine use of either Watson’s U2 test or MANOVA approach when comparing two samples of circular data.Publisher PDFPeer reviewe

Model selection versus traditional hypothesis testing in circular statistics : a simulation study

L.L. was partially funded by the Austrian Science Fund [FWF, grant number: P32586].Many studies in biology involve data measured on a circular scale. Such data require different statistical treatment from those measured on linear scales. The most common statistical exploration of circular data involves testing the null hypothesis that the data show no aggregation and are instead uniformly distributed over the whole circle. The most common means of performing this type of investigation is with a Rayleigh test. An alternative might be to compare the fit of the uniform distribution model to alternative models. Such model-fitting approaches have become a standard technique with linear data, and their greater application to circular data has been recently advocated. Here we present simulation data that demonstrate that such model-based inference can offer very similar performance to the best traditional tests, but only if adjustment is made in order to control type I error rate.Publisher PDFPeer reviewe

Grouped circular data in biology : advice for effectively implementing statistical procedures

Open access funding provided by Austrian Science Fund (FWF). LL was partially funded by the Austrian Science Fund (FWF, Grant Number: P32586).The most common statistical procedure with a sample of circular data is to test the null hypothesis that points are spread uniformly around the circle without a preferred direction. An array of tests for this has been developed. However, these tests were designed for continuously distributed data, whereas often (e.g. due to limited precision of measurement techniques) collected data is aggregated into a set of discrete values (e.g. rounded to the nearest degree). This disparity can cause an uncontrolled increase in type I error rate, an effect that is particularly problematic for tests that are based on the distribution of arc lengths between adjacent points (such as the Rao spacing test). Here, we demonstrate that an easy-to-apply modification can correct this problem, and we recommend this modification when using any test, other than the Rayleigh test, of circular uniformity on aggregated data. We provide R functions for this modification for several commonly used tests. In addition, we tested the power of a recently proposed test, the Gini test. However, we concluded that it lacks sufficient increase in power to replace any of the tests already in common use. In conclusion, using any of the standard circular tests (except the Rayleigh test) without modifications on rounded/aggregated data, especially with larger sample sizes, will increase the proportion of false-positive results—but we demonstrate that a simple and general modification avoids this problem.Publisher PDFPeer reviewe

The multivariate analysis of variance as a powerful approach for circular data

LL is supported by the Austrian Science Fund (FWF, Grant Number: P32586). EPM receives funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 948728).Background A broad range of scientific studies involve taking measurements on a circular, rather than linear, scale (often variables related to times or orientations). For linear measures there is a well-established statistical toolkit based on linear modelling to explore the associations between this focal variable and potentially several explanatory factors and covariates. In contrast, statistical testing of circular data is much simpler, often involving either testing whether variation in the focal measurements departs from circular uniformity, or whether a single explanatory factor with two levels is supported. Methods We use simulations and example data sets to investigate the usefulness of a MANOVA approach for circular data in comparison to commonly used statistical tests. Results Here we demonstrate that a MANOVA approach based on the sines and cosines of the circular data is as powerful as the most-commonly used tests when testing deviation from a uniform distribution, while additionally offering extension to multi-factorial modelling that these conventional circular statistical tests do not. Conclusions The herein presented MANOVA approach offers a substantial broadening of the scientific questions that can be addressed statistically using circular data.Publisher PDFPeer reviewe

Exploring Design Principles and Design Features for a Business Game to Teach the Relationship Between Business Models and Business Processes

Both business models and business processes represent crucial concepts for research and practice. Since both topics affect each other directly, understanding their connection is essential. However, literature does not provide a teaching concept focusing on their relationship. Using a business game could provide a suitable solution for that purpose due to its features. Therefore, the goal of this paper is to design and evaluate a business game that can be used to teach the relationship between business models and business processes. Towards this end, we apply a design science research approach to build the business game. Based on our identified design requirements, we introduce a set of design principles guiding our design process. Moreover, we demonstrate a prototypical instantiation using design features and evaluate our results with focus groups. Our work contributes to the design knowledge base of business games in the context of business models and business processes

Empathic Patterns in Complex Discourse

Successful functioning at organizational settings in a complex, shifting and vague era, such as the Covid- 19 pandemic, requires soft skills. The present study attempts to contribute to the existing body of knowledge on empathy - an essential 21st century soft skill - by honing on the explicit and expressive aspects of empathic competencies. In accordance with our aim to identify, transcribe and demonstrate empathic patterns in complex interactions in the field of education, we conducted a collaborative qualitative analysis of videotaped simulations of emotionally charged interactions, which occur in school and other educational settings. This led to the development of the Empathic Patterns in Interpersonal Communication (EPIC) conceptual model addressing cognitive, emotional and behavioral elements of empathy. The importance of EPIC, which represents an initial step in conceptualizing empathic patterns, is that it could be implemented as a practical tool that encourages effective communication among students and teachers