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Kurzfassung Die zunehmende Nachfrage nach effizienten elektrischen Maschinen mit hohen Leistungsdichten in der Automobilindustrie fuhrt ebenso zu steigenden Anforderungen an die Herstellung von der...

In this work, a new nonlinear dynamic (6D) system of equations is proposed that describes the process of magnetic field generation. This system of equations is an alternative to the Rikitake dynamo system describing chaotic magnetic field reversals.The behavior of the new dynamical system is studied by analyzing the stability of equilibrium points. For fixed parameters of the 6D dynamical system, the spectrum of Lyapunov exponents and the Kaplan-York dimension are calculated. The presence of two positive Lyapunov exponents demonstrates the hyperchaotic behavior of the 6D dynamical system. The fractional Kaplan-York dimension indicates the fractal structure of strange attractors. We have shown that an adaptive controller is used to stabilize the novel 6D chaotic system with unknown system parameters. An active control method is derived to achieve global chaotic synchronization of two identical novels 6D chaotic systems with unknown system parameters. Based on the results obtained in Matlab-Simulink and LabVIEW models, a chaotic signal generator for the 6D chaotic system is implemented in the Multisim environment. The results of chaotic behavior simulation in the Multisim environment show similar behavior when comparing simulation results in Matlab-Simulink and LabVIEW models.

In this paper, Matlab-Simulink and LabView models are constructed for a new nonlinear dynamic system of equations in an eight-dimensional (8D) phase space. For fixed parameters of the 8D dynamical system, the spectrum of Lyapunov exponents and the Kaplan-York dimension are calculated. The presence of two positive Lyapunov exponents demonstrates the hyperchaotic behavior of the 8D dynamical system. The fractional Kaplan-York dimension indicates the fractal structure of strange attractors. We have shown that an adaptive controller is used to stabilize the novel 8D chaotic system with unknown system parameters. An active control method is derived to achieve global chaotic synchronization of two identical novel 8D chaotic systems with unknown system parameters. Based on the results obtained in Matlab-Simulink and LabView models, a chaotic signal generator for the 8D chaotic system is implemented in the Multisim environment. The results of chaotic behavior simulation in the Multisim environment show similar behavior when comparing simulation results in Matlab-Simulink and LabView models.

Observable signatures of the quantum nature of gravity at low energies have recently emerged as a promising new research field. One prominent avenue is to test for gravitationally induced entanglement between two mesoscopic masses prepared in spatial superposition. Here we analyze such proposals and what one can infer from them about the quantum nature of gravity, as well as the electromagnetic analogues of such tests. We show that it is not possible to draw conclusions about mediators: even within relativistic physics, entanglement generation can equally be described in terms of mediators or in terms of non-local processes -- relativity does not dictate a local channel. Such indirect tests therefore have limited ability to probe the nature of the process establishing the entanglement as their interpretation is inherently ambiguous. We also show that cosmological observations already demonstrate some aspects of quantization that these proposals aim to test. Nevertheless, the proposed experiments would probe how gravity is sourced by spatial superpositions of matter, an untested new regime of quantum physics., 23 pages, 3 figures

We test the degree to which interacting Bosonic systems can be approximated by a classical field as total occupation number is increased. This is done with our publicly available code repository, \href{https://github.com/andillio/QIBS}{QIBS}, a massively parallel solver for these systems. We use a number of toy models well studied in the literature and track when the classical field description admits quantum corrections, called the quantum breaktime. This allows us to test claims in the literature regarding the rate of convergence of these systems to the classical evolution. We test a number of initial conditions, including coherent states, number eigenstates, and field number states. We find that of these initial conditions, only number eigenstates do not converge to the classical evolution as occupation number is increased. We find that systems most similar to scalar field dark matter exhibit a logarithmic enhancement in the quantum breaktime with total occupation number. Systems with contact interactions or with field number state initial conditions, and linear dispersions, exhibit a power law enhancement. Finally, we find that the breaktime scaling depends on both model interactions and initial conditions., To be submitted to Phys Rev D

We introduce a numerical method and python package, https://github.com/andillio/CHiMES, that simulates quantum systems initially well approximated by mean field theory using a second order extension of the classical field approach. We call this the field moment expansion method. In this way, we can accurately approximate the evolution of first and second field moments beyond where the mean field theory breaks down. This allows us to estimate the quantum breaktime of a classical approximation without any calculations external to the theory. We investigate the accuracy of the field moment expansion using a number of well studied quantum test problems. Interacting Bosonic systems similar to scalar field dark matter are chosen as test problems. We find that successful application of this method depends on two conditions: the quantum system must initially be well described by the classical theory, and that the growth of the higher order moments be hierarchical., Accepted to Phys. Rev. D

In recent years, experiments with flows of liquid metals in a helical magnetic field have been actively carried out. The study of the processes of mixing and crystallization of a liquid metal is of practical importance for metallurgy. With the development of nanotechnology, more and more new types of nanofluids (hybrid, ternary nanofluids) are being synthesized, and the thermophysical characteristics of which can compete with liquid metals. This circumstance served as a motivation for conducting this theoretical study. In this study, the criterion for the onset of convection in a Darcy–Brinkman porous medium layer saturated by an electrically conductive nanofluid under a helical magnetic field is investigated. The Brownian motion and thermophoresis effects are combined in the model for nanofluids, whereas the Darcy–Brinkman model is used for porous media. Instead of prescribing the nanoparticle volume fraction on the borders, we adopted a boundary condition in which the nanoparticle flow is considered to be zero. In the absence of a temperature gradient, a new type of instability in a helical magnetic field in a thin layer of a nanofluid is considered. The growth rate and the region of the development of this instability are numerically obtained depending on the profile of the azimuthal magnetic field (the magnetic Rossby number [Formula: see text]) and the radial wave number [Formula: see text]. In the presence of temperature, the stationary regime of nonuniformly rotating magnetoconvection is studied. The accurate analytical equation for the critical Rayleigh–Darcy number in terms of various non-dimensional parameters is determined using the linear stability theory. The results show that rotation and the axial (vertical) part of the helical magnetic field retard the onset of convection. While the azimuthal part of the helical magnetic field has a destabilizing effect at positive Rossby numbers [Formula: see text]. The conditions for stabilization and destabilization of stationary convection in a helical magnetic field are determined for metal oxide, metallic, and semiconductor nanofluids.

Axion-like particles (ALPs) are promising dark matter candidates. They are typically described by a classical field, motivated by large phase space occupation numbers. Here we show that such a description is accompanied by a quantum effect: squeezing due to gravitational self-interactions. For a typical QCD axion today, the onset of squeezing is reached on $\mathrm{\mu s}$-scales and grows over millennia. Thus within the usual models based on the classical Schr\"odinger-Poisson equation, a type of Gross-Pitaevskii equation, any viable ALP is nonclassical. We also show that squeezing may be relevant on the scales of other self-gravitating systems such as galactic haloes, or solitonic cores. Conversely, our results highlight the incompleteness and limitations of the classical single field description of ALPs., Comment: 13 pages, 3 figures, extended discussion and minor changes

This study investigates the combined influence of the Hall current and the axial magnetic field on the criterion for the onset of convection in a nonuniformly rotating layer of electrically conductive nanofluids taking into account the effects of Brownian diffusion and thermophoresis. The analytical and numerical computations are presented for water-based nanofluids with alumina nanoparticles. In the absence of a temperature gradient, a new type of magnetorotational instability in an axial magnetic field in a thin layer of a nanofluid is considered. The growth rate and regions of development of this instability are numerically obtained depending on the angular velocity profile (the Rossby number Ro) and the radial wavenumber k. In the presence of temperature and nanoparticle concentration gradients, the stationary regime of nonuniformly rotating magnetoconvection is studied. The exact analytical expression for critical Rayleigh number [Formula: see text] is obtained in terms of various nondimensional parameters. The results indicate that the increase in the Lewis number, the modified diffusivity ratio, and the concentration Rayleigh number is to accelerate the onset of convection. The increase in the Hall current parameter can delay or enhance the onset of convective instability. Rotation profiles with negative Rossby numbers lower the threshold for the development of thermal instability and stimulate the onset of convection. The conditions for stabilization and destabilization of stationary convection in an axial magnetic field are determined. The results are represented graphically and verified numerically.

Die Autoren beleuchten hochschulische Bildungsmöglichkeiten mit Massive Open Online Cours (MOOC) von der Erstellung bis zur Durchführung derartiger Kurse. Dabei scheinen die beliebige Wiederholbarkeit von Vorlesungen und die dauernde Abrufbarkeit von Lektionen wesentlich zum Erfolg des Formats beizutragen. (DIPF/Orig.)

Recent developments in vehicle electrification lead to increasing requirements for electrical machines regarding power output and cost-effective manufacturing. Here, the stator is one of the main active electromagnetic subassemblies, offering significant potential to raise total power output. Therefore, recent studies focus on maximizing copper fill factors by enhancing stator-winding technologies or by inventing new manufacturing approaches.

We perform the first test of dark matter (DM) stress-energy evolution through cosmic history, using cosmic microwave background measurements supplemented with baryon acoustic oscillation data and the Hubble Space Telescope key project data. We constrain the DM equation of state (EoS) in 8 redshift bins, and its sound speed and (shear) viscosity in 9 redshift bins, finding no convincing evidence for non-$\Lambda$CDM values in any of the redshift bins. Despite this enlarged parameter space, the sound speed and viscosity are constrained relatively well at late times (due to the inclusion of CMB lensing), whereas the EoS is most strongly constrained around recombination. These results constrain for the first time the level of "coldness" required of DM across various cosmological epochs at both the background and perturbative levels. We show that simultaneously allowing time dependence for both the EoS and sound speed parameters shifts the posterior of the DM abundance before recombination to a higher value, while keeping the present day DM abundance similar to the $\Lambda$CDM value. This shifts the posterior for the present day Hubble constant compared to $\Lambda$CDM, suggesting that DM with time-dependent parameters is well-suited to explore possible solutions to persistent tensions within the $\Lambda$CDM model. We perform a detailed comparison with our previous study involving a vanishing sound speed and viscosity using the same datasets in order to explain the physical mechanism behind these shifts., Comment: 20 pages, 10 figures, 5 tables; updated to match version published in PRD

Against the background of rising electro mobility concepts for vehicles, corresponding demands on electric machines with regard to their efficiency and power density remarkably influence stator production of such machines in terms of required power output. Here, fundamental parameters that must be considered when designing stators are magnetic properties of the stator core and the electric properties of the winding. Furthermore, the performance of stators is influenced by geometrical properties such as copper filling of the stator grooves and the inner radius of the stator core. In order to increase copper fill factors within the stator body, several stator production technologies have recently been developed and investigated, e.g. hairpin, flyer winding and insertion technology. In addition to those technologies, the so called flatpack bending process constitutes a new process for stator production in which the pre-bent winding is first inserted into a flat, comb like shaped stator core. This assembly is subsequently rounded in a multi-stage rotary draw bending process, obtaining high copper filling ratios. However, the main challenge for this bending and subsequent springback procedure arises from the roundness deviations occurring along current process chains. For this reason, a simulation model has been created in the framework of a collaborative research project between SEG Automotive and the Institute for Metal Forming Technology, Stuttgart, aiming to better understand and to improve this stator flatpack bending process. For an extensive validation of this model, various parameters need to be examined and their influence to be evaluated. In this study, simulations were performed using this numerical model, in which levels of yield strength of the material to be formed were varied in order to calculate their influences on the outer radius. For validation objectives of simulation results, bending experiments were subsequently conducted, so samples obtained were evaluated using 3D scan technology. As a result, only a maximum difference of 0.3 mm of bent stator core was observed by comparing the numerically calculated results and the results measured during the experiments.

Constraints on the properties of the cosmological dark matter have previously been obtained in a model-independent fashion using the Generalised Dark Matter (GDM) framework. Here we extend that work in several directions: We consider the inclusion of WiggleZ matter power spectrum data, and show that this improves the constraints on the two perturbative GDM parameters, $c^2_s$ and $c^2_\text{vis}$, by a factor of 3, for a conservative choice of wavenumber range. A less conservative choice can yield an improvement of up to an order of magnitude compared to previous constraints. In order to examine the robustness of this result we develop a GDM halo model to explore how non-linear structure formation could proceed in this framework, since currently GDM has only been defined perturbatively and only linear theory has been used when generating constraints. We then examine how the halo model affects the constraints obtained from the matter power spectrum data. The less-conservative wavenumber range shows a significant difference between linear and non-linear modelling, with the latter favouring GDM parameters inconsistent with $\Lambda$CDM, underlining the importance of careful non-linear modelling when using this data. We also use this halo model to establish the robustness of previously obtained constraints, particularly those that involve weak gravitational lensing of the cosmic microwave background. Additionally, we show how the inclusion of neutrino mass as a free parameter affects previous constraints on the GDM parameters., Comment: 27 pages, 10 figures. Updated to match published version: a few minor clarifications on the choices in the halo model construction and relation to WDM and an additional plot showing the mass function

We revisit the status of scalar-tensor theories with applications to dark energy in the aftermath of the gravitational wave signal GW170817 and its optical counterpart GRB170817A. At the level of the cosmological background, we identify a class of theories, previously declared unviable in this context, whose anomalous gravitational wave speed is proportional to the scalar equation of motion. As long as the scalar field is assumed not to couple directly to matter, this raises the possibility of compatibility with the gravitational wave data, for any cosmological sources, thanks to the scalar dynamics. This newly "rescued" class of theories includes examples of generalised quintic galileons from Horndeski theories. Despite the promise of this leading order result, we show that the loophole ultimately fails when we include the effect of large scale inhomogeneities., Updated with corrections to the gravitational wave propagation coming from higher order terms in the presence of large scale inhomogeneities. These close off any remaining loopholes. References added

Federated learning is an emerging collaborative machine-learning paradigm for training models directly on edge devices. The data remains on the edge device and this method is robust under real-world edge data distributions. We present a new asynchronous federated-learning algorithm (‘asynchronous federated learning’) and study its convergence rate when distributed across many edge devices, with hard data constraints, relative to training the same model on a single device. We compare asynchronous federated learning to an existing synchronous method. We evaluate its robustness in real-world situations; for example, devices joining part-way through training or devices with heterogeneous compute resources. We then apply asynchronous federated learning to a challenging geospatial application, namely image-based geolocation using a state-of-the-art convolutional neural network. Our results lay the groundwork for deploying large-scale federated learning as a tool to automatically learn, and continually update, a machine-learned model that encodes location.

International audience; Continuous environmental change-such as slowly rising temperatures-may create permanent maladaptation of natural populations: Even if a population adapts evolutionarily, its mean phenotype will usually lag behind the phenotype favored in the current environment, and if the resulting phenotypic lag becomes too large, the population risks extinction. We analyze this scenario using a moving-optimum model, in which one or more quantitative traits are under stabilizing selection towards an optimal value that increases at a constant rate. We have recently shown that, in the limit of infinitely small mutations and high mutation rate, the evolution of the phenotypic lag converges to an Ornstein-Uhlenbeck process around a long-term equilibrium value. Both the mean and the variance of this equilibrium lag have simple analytical formulas. Here, we study the properties of this limit and compare it to simulations of an evolving population with finite mutational effects. We find that the small-jumps limit provides a reasonable approximation, provided the mean lag is so large that the optimum cannot be reached by a single mutation. This is the case for fast environmental change and/or weak selection. Our analysis also provides insights into population extinction: Even if the mean lag is small enough to allow a positive growth rate, stochastic fluctuations of the lag will eventually cause extinction. We show that the time until this event follows an exponential distribution, This study benefited from a PHC Amadeus exchange grant (project number 31642SJ) to whose mean depends strongly on a composite parameter that relates the speed of environmental change to the adaptive potential of the population.

International audience; According to a recent survey, ecologists and evolutionary biologists feel that theoretical and empirical research should coexist in a tight feedback loop but believe that the two domains actually interact very little. We evaluate this perception using a citation network analysis for two data sets, representing the literature on sexual selection and speciation. Overall, 54%-60% of citations come from a paper's own category, whereas 17%-23% are citations across categories. These cross-citations tend to focus on highly cited papers, and we observe a positive correlation between the numbers of citations a study receives within and across categories. We find evidence that reviews can function as integrators between the two literatures, argue that theoretical models are analogous to specific empirical study systems, and complement our analyses by studying a cocitation network. We conclude that theoretical and empirical research are more tightly connected than generally thought but that avenues exist to further increase this integration.

Cold Dark Matter (CDM) is a crucial constituent of the current concordance cosmological model. Having a vanishing equation of state (EoS), its energy density scales with the inverse cosmic volume and is thus uniquely described by a single number, its present abundance. We test the inverse cosmic volume law for Dark Matter (DM) by allowing its EoS to vary independently in eight redshift bins in the range $z=10^5$ and $z=0$. We use the latest measurements of the Cosmic Microwave Background radiation from the Planck satellite and supplement them with Baryon Acoustic Oscillation (BAO) data from the 6dF and SDSS-III BOSS surveys, and with the Hubble Space Telescope (HST) key project data. We find no evidence for nonzero EoS in any of the eight redshift bins. With Planck data alone, the DM abundance is most strongly constrained around matter-radiation equality $\omega^{\rm eq}_g = 0.1193^{+0.0036}_{-0.0035}$ (95% c.l.), whereas its present day value is more weakly constrained $\omega^{(0)}_g = 0.16^{+0.12}_{-0.10}$ (95% c.l.). Adding BAO or HST data does not significantly change the $\omega^{\rm eq}_g$ constraint, while $\omega^{(0)}_g$ tightens to $0.160^{+0.069}_{-0.065} $ (95% c.l.) and $0.124^{+0.081}_{-0.067}$ (95% c.l.) respectively. Our results constrain for the first time the level of "coldness" required of the DM across various cosmological epochs and show that the DM abundance is strictly positive at all times., Comment: 6 pages, 4 figures, changed color scheme for figures

Der Horizon Report als wichtiger Gradmesser fur den Einsatz digitaler Technologien in Unterricht und Lehre streicht seit Jahren die Bedeutung von Mobile Learning bzw. Bring Your Own Device (BYOD) heraus. Gleichzeitig werden die damit verbundenen Herausforderungen, die sich aus der Verschmelzung von formellen und informellen sowie digitalen und physischen Lernwelten ergeben, thematisiert. Massive Open Online Courses (MOOCs) konnen bei der Zusammenfuhrung unterschiedlicher Lernwelten helfen. Sie sind in ihrer klassischen Definition fur alle Interessierten online verfugbar und frei zuganglich und damit pradestiniert fur das zeit- und ortsunabhangige Lernen. Ihre Nutzung auf mobilen Endgeraten liegt auf der Hand. Allerdings sind die gangigen Funktionalitaten eines MOOC wie das Abspielen von Videos, die Beantwortung von Selbsttestfragen oder die Beteiligung an Diskussionsforen sehr haufig nicht auf die Darstellung kleiner Displays ausgelegt. Ausgehend von einer kurzen allgemeinen Einfuhrung zu MOOCs beschaftigt sich der Beitrag mit ihrem Einsatzpotenzial auf mobilen Endgeraten. Gleichzeitig werden damit verbundene Herausforderungen thematisiert und Handlungsempfehlungen fur die fur mobile Endgerate optimierte Konzeption von MOOCs gegeben.

The automotive industry is currently experiencing an unprecedented amount of innovation and introducing new technologies in almost every field. Even with all of these exciting new developments, one of the most important points is to maintain or improve the reliability and lifetime of cars. In response to these demands, automotive manufacturers and suppliers have worked to strengthen their expertise in this area.

The Kalman filter is a well-established approach to get information on the time-dependent state of a system from noisy observations. It was developed in the context of the Apollo project to see the deviation of the true trajectory of a rocket from the desired trajectory. Afterwards it was applied to many different systems with small numbers of components of the respective state vector (typically about 10). In all cases the equation of motion for the state vector was known exactly. The fast dissipative magnetization dynamics is often investigated by x-ray magnetic circular dichroism movies (XMCD movies), which are often very noisy. In this situation the number of components of the state vector is extremely large (about 10(5)), and the equation of motion for the dissipative magnetization dynamics (especially the values of the material parameters of this equation) is not well known. In the present paper it is shown by theoretical considerations that - nevertheless - there is no principle problem for the use of the Kalman filter to denoise XMCD movies of fast dissipative magnetization dynamics.

We demonstrate that the Vlasov equation describing collisionless self-gravitating matter may be solved with the so-called Schr\"odinger method (ScM). With the ScM, one solves the Schr\"odinger-Poisson system of equations for a complex wave function in d dimensions, rather than the Vlasov equation for a 2d-dimensional phase space density. The ScM also allows calculating the d-dimensional cumulants directly through quasi-local manipulations of the wave function, avoiding the complexity of 2d-dimensional phase space. We perform for the first time a quantitive comparison of the ScM and a conventional Vlasov solver in d=2 dimensions. Our numerical tests were carried out using two types of cold cosmological initial conditions: the classic collapse of a sine wave and those of a gaussian random field as commonly used in cosmological cold dark matter N-body simulations. We compare the first three cumulants, that is, the density, velocity and velocity dispersion, to those obtained by solving the Vlasov equation using the publicly available code ColDICE. We find excellent qualitative and quantitative agreement between these codes, demonstrating the feasibility and advantages of the ScM as an alternative to N-body simulations. We discuss, the emergence of effective vorticity in the ScM through the winding number around the points where the wave function vanishes. As an application we evaluate the background pressure induced by the non-linearity of large scale structure formation, thereby estimating the magnitude of cosmological backreaction. We find that it is negligibly small and has time dependence and magnitude compatible with expectations from the effective field theory of large scale structure., Comment: 29 pages, 14 figures, corresponds to published version

International audience; The large body of theory on speciation with gene flow has brought to light fundamental differences in the effects of two types of mating rules on speciation: preference/trait rules, in which divergence in both (female) preferences and (male) mating traits is necessary for assortment, and matching rules, in which individuals mate with like individuals on the basis of the presence of traits or alleles that they have in common. These rules can emerge from a variety of behavioral or other mechanisms in ways that are not always obvious. We discuss the theoretical properties of both types of rules and explain why speciation is generally thought to be more likely under matching rather than preference/trait rules. We furthermore discuss whether specific assortative mating mechanisms fall under a preference/trait or matching rule, present empirical evidence for these mechanisms, and propose empirical tests that could distinguish between them. The synthesis of the theoretical literature on these assortative mating rules with empirical studies of the mechanisms by which they act can provide important insights into the occurrence of speciation with gene flow. Finally, by providing a clear framework we hope to inspire greater alignment in the ways that both theoreticians and empiricists study mating rules and how these rules affect speciation through maintaining or eroding barriers to gene flow among closely related species or populations.

Massive Open Online Courses (MOOCs) und Open Educational Resources (OER) sind Schlagworte der heutigen Bildungswelt. In diesem Beitrag fuhren wir in beide ein und erklaren ihre Abhangigkeit und ihren Zusammenhang. Anhand zweier Beispiele – „oncampus an der Fachhochschule Lubeck sowie „iMooX“ von zwei Grazer Universitaten“ – werden erste Erfahrungen mit MOOCs und OER aufgezeigt. In der abschliesenden Diskussion sind sowohl die Herausforderungen als auch die bereits ersichtlichen Vorteile Teil der Betrachtung. Der Beitrag schliest mit der Erkenntnis, dass OER ein wichtiger Bestandteil des Bildungssystems von morgen sind.

We investigate large scale structure formation of collisionless dark matter in the phase space description based on the Vlasov-Poisson equation. We present the Schrödinger method, originally proposed by \cite{WK93} as numerical technique based on the Schrödinger Poisson equation, as an analytical tool which is superior to the common standard pressureless fluid model. Whereas the dust model fails and develops singularities at shell crossing the Schrödinger method encompasses multi-streaming and even virialization.

bstract: In general, participants use MOOCs for individual learning purposes by selecting certain contents of a MOOC in which they are interested. Simultaneously, MOOCs are used in the context of online-lectures offered to students who must or may enroll for a specific course to earn credits. However, many participants do not successfully complete all units of a MOOC. Therefore, completion rates —in general— are rather low. Certificates like PDF-documents or electronic badges can be an adequate stimulation to complete a course. This research raises the questions, how the certification of MOOC-participants can be managed and if certificates have an impact on completion rates. Firstly, general aspects of certification are discussed. This is followed by a practical insight into the certification practice based on experiences of the Austrian MOOC-platform iMooX operators. As a conclusion, results are summarized and related challenges and further research questions are addressed. De forma general, los participantes de los cursos MOOC acuden a ellos por deseos personales de aprender, por lo que seleccionan ciertos contenidos del MOOC en el que están interesados. A su vez, los MOOC también se emplean en el contexto de clases en línea que se ofrecen al alumnado que necesita alcanzar créditos académicos en su formación. Sin embargo, muchos participantes no finalizan todo el curso MOOC y las tasas de éxito son, en general, relativamente bajas. Los certificados en forma de documentos PDF, o distintivos en forma de credencial (badges), pueden resultar de estímulo para finalizar estos cursos. Esta investigación analiza cómo se puede afrontar la certificación de los participantes en un curso MOOC y si la certificación tiene, de alguna manera, incidencia en las tasas de éxito. En primer lugar, se discuten aspectos generales de la certificación y, a continuación, se realiza un análisis práctico con base en la plataforma MOOC austriaca iMooX. Las conclusiones muestran los principales retos e investigaciones derivadas del estudio y su desarrollo futuro.

MOOCs (Massive Open Online Courses) have developed into one of the most prominent instruments of technology-enhanced learning, and their much-praised potential has often been connected to one of their core components: openness. In theory, this feature not only ensures free access to content, but also affects other aspects that enable participants to make the most of their learning experience, like re-using and copying materials or even creating derivative works. In practice, however, most MOOCs do not subscribe to these more advanced principles of openness, especially those provided by for-profit platforms.

Purpose To determine the efficacy and feasibility of induction chemotherapy (ICT) with docetaxel, cisplatin and 5-fluorouracil followed by radiotherapy and cetuximab (C) in patients with locally advanced head and neck cancer. Patients and methods Forty-nine previously untreated patients with local advanced stage III and IV squamous cell carcinoma of the head and neck (SCCHN) received three courses of ICT consisting of docetaxel 75 mg/m2 day 1, cisplatin 75 mg/m2 day 1 and infusional 5-fluorouracil 750 mg/m2/day on days 1–5 followed by radiotherapy plus C at 250 mg/m2/week (after an initial loading dose of 400 mg/m2). Results After completion of ICT 44 of 49 patients received radiotherapy plus C. Three months after therapy completion tumour response was observed in 33 patients and after two years, 25 patients were in complete remission (CR). The most common grade 4 toxicity during the whole treatment period was dermatitis (30%), followed by mucositis (27%) and neutropenia (17%) without fever. One toxic related death was observed during ICT. Two-year progression-free survival (PFS) rate was 59% and two-year overall survival (OS) rate was 63%, respectively. Conclusion Concurrent radiotherapy plus C after three courses of ICT was feasible and was associated with promising CR, PFS and OS rates. Further optimisation of dose and sequence is warranted.

We calculate the halo correlation function in redshift space using the Gaussian streaming model (GSM). To determine the scale-dependent functions entering the GSM, we use local Lagrangian bias together with convolution Lagrangian perturbation theory (CLPT), which constitutes an approximation to the Post-Zel'dovich approximation. On the basis of $N$-body simulations, we demonstrate that a smoothing of the initial conditions with the Lagrangian radius improves the Zel'dovich approximation and its ability to predict the displacement field of protohalos. Based on this observation, we implement a ``truncated'' CLPT by smoothing the initial power spectrum and investigate the dependence of the streaming model ingredients on the smoothing scale. We find that the real space correlation functions of halos and their mean pairwise velocity are optimized if the coarse graining scale is chosen to be $1\text{ }\text{ }\mathrm{Mpc}/h$ at $z=0$, while the pairwise velocity dispersion is optimized if the smoothing scale is chosen to be the Lagrangian size of the halo. We compare theoretical results for the halo correlation function in redshift space to measurements within the Horizon run 2 $N$-body simulation halo catalog. We find that this simple two-filter smoothing procedure in the spirit of the truncated Zel'dovich approximation significantly improves the $\mathrm{GSM}+\mathrm{CLPT}$ prediction of the redshift space halo correlation function over the whole mass range from large galaxy to galaxy cluster--sized halos. We expect that the necessity for two filter scales is an artifact of our local bias model, and that once a more physical bias model is implemented in CLPT, the only physically relevant smoothing scale will be related to the Lagrangian radius, in accord with our findings based on $N$-body simulations.

In this chapter, we discuss why open educational resources (OER) and MOOCs are a necessary and powerful combination, especially in German-speaking Europe. We begin with an introduction to open online courses and an overview of copyright law in Germany and Austria. We then describe the evolution of OER MOOCs in Austria and Germany, especially the development of two MOOC platforms. Finally, we present examples of the impact of OER on MOOCs to conclude that an approach combining OER and MOOCs can be very valuable to foster new and innovative didactical approaches as well as future education.

The extent to which sexual selection is involved in speciation with gene flow remains an open question and the subject of much research. Here, we propose that some insight can be gained from considering the concept of magic traits (i.e., traits involved in both reproductive isolation and ecological divergence). Both magic traits and other, “non-magic”, traits can contribute to speciation via a number of specific mechanisms. We argue that many of these mechanisms are likely to differ widely in the extent to which they involve sexual selection. Furthermore, in some cases where sexual selection is present, it may be prone to inhibit rather than drive speciation. Finally, there are a priori reasons to believe that certain categories of traits are much more effective than others in driving speciation. The combination of these points suggests a classification of traits that may shed light on the broader role of sexual selection in speciation with gene flow. In particular, we suggest that sexual selection can act as a driver of speciation in some scenarios, but may play a negligible role in potentially common categories of magic traits, and may be likely to inhibit speciation in common categories of non-magic traits.

Whereas a rich literature exists for estimating population genetic divergence, metrics of phenotypic trait divergence are lacking, particularly for comparing multiple traits among three or more populations. Here, we review and analyze via simulation Hedges’ g, a widely used parametric estimate of effect size. Our analyses indicate that g is sensitive to a combination of unequal trait variances and unequal sample sizes among populations and to changes in the scale of measurement. We then go on to derive and explain a new, non-parametric distance measure, “Δp”, which is calculated based upon a joint cumulative distribution function (CDF) from all populations under study. More precisely, distances are measured in terms of the percentiles in this CDF at which each population’s median lies. Δp combines many desirable features of other distance metrics into a single metric; namely, compared to other metrics, p is relatively insensitive to unequal variances and sample sizes among the populations sampled. Furthermore, a key feature of Δp—and our main motivation for developing it—is that it easily accommodates simultaneous comparisons of any number of traits across any number of populations. To exemplify its utility, we employ Δp to address a question related to the role of sexual selection in speciation: are sexual signals more divergent than ecological traits in closely related taxa? Using traits of known function in closely related populations, we show that traits predictive of reproductive performance are, indeed, more divergent and more sexually dimorphic than traits related to ecological adaptation [Current Zoology 58 (3): 423-436, 2012].

The extent to which sexual selection is involved in speciation with gene flow remains an open question and the subject of much research. Here, we propose that some insight can be gained from considering the concept of magic traits (i.e., traits involved in both reproductive isolation and ecological divergence). Both magic traits and other, “non-magic”, traits can contribute to speciation via a number of specific mechanisms. We argue that many of these mechanisms are likely to differ widely in the extent to which they involve sexual selection. Furthermore, in some cases where sexual selection is present, it may be prone to inhibit rather than drive speciation. Finally, there are a priori reasons to believe that certain categories of traits are much more effective than others in driving speciation. The combination of these points suggests a classification of traits that may shed light on the broader role of sexual selection in speciation with gene flow. In particular, we suggest that sexual selection can act as a driver of speciation in some scenarios, but may play a negligible role in potentially common categories of magic traits, and may be likely to inhibit speciation in common categories of non-magic traits [Current Zoology 58 (3): 507–513, 2012].