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The presence of cooperative learning in Spanish classes: observation and analysis of problems
Hanzalová, Marie Anna ; González Lozano, Javier (advisor) ; Čermák, Petr (referee)
The primary objective of the present study was to conduct an analysis of the presence of cooperative learning in Spanish as a foreign language (ELE) classes in the Czech Republic, with a specific focus on identifying the main challenges encountered by secondary school teachers during this process. To accomplish this goal, a mixed-method research approach was employed, utilizing an online questionnaire specifically designed for Spanish teachers. The initial section of the questionnaire encompassed an investigation into the participants' level of familiarity with the term "cooperative learning," as well as their knowledge and utilization of various cooperative techniques. Furthermore, the study explored the specific areas in which cooperative learning was applied, the essential prerequisites for its successful implementation, and the associated benefits linked to this pedagogical methodology. Conversely, the subsequent section of the questionnaire centred around examining the perceived obstacles encountered by teachers, students, and external factors that negatively impact the integration of cooperative learning within the classroom environment. The research findings underscored the widespread awareness regarding the concept of cooperative learning, with each teacher, on average, demonstrating...
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The Role of Charge Regulation in Weak Polyampholytes
Lunkad, Raju ; Košovan, Peter (advisor) ; de Sousa Dias, Rita (referee) ; Gonzalez, Jose Luis Garces (referee)
A weak polyampholyte is a polymer that consists of both acid and base groups along the chain. In aqueous solutions, these groups dissociate in a certain pH range, leading to a dramatic change in the overall charge of the polyampholyte from positive to negative as the pH increases. The ability of weak ampholytes to switch their charge in response to changes in pH makes them useful in various applications. Despite the considerable research on weak polyampholytes, the understanding of some aspects is still insufficient. To address this, I systematically investigated the charge regulation of weak polyam- pholytes, specifically peptides, both in solution and during their interaction with polyelectrolytes. Furthermore, I also looked at the charge regulation of polyzwitterions. All these studies were carried out using a simple coarse-grained bead-spring model in Langevin dynamics simulations. In addition, I used the constant-pH ensemble to account for the ionization reactions of acid and base groups in the implicit solvent. Through our simulations, we made significant advancements in understanding how charges and the ionization states of acid and base groups in various peptides and polyzwitterions respond to pH changes. By comparing simulation results with the ideal results predicted by the...
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Direct construction of reciprocal mass matrix and higher order fininite element method
Cimrman, Robert ; Kolman, Radek ; González, J. A. ; Park, K. C.
When solving dynamical problems of computational mechanics, such as contact-impact problems or cases involving complex structures under fast loading conditions, explicit time-stepping algorithms are usually preferred over implicit ones. The explicit schemes are normally combined with the lumped (diagonal) mass matrix so that the calculations are efficient and moreover dispersion errors in wave propagation are partially eliminated. As an alternative to lumping with advantageous properties, the reciprocal mass matrix is an inverse mass matrix that has the same sparsity structure as the original consistent mass matrix, preserves the total mass, captures well the desired frequency spectrum and leads thus to efficient and accurate calculations. In the contribution we comment on the usability of the reciprocal mass matrix in connection with higher order FEM.
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Localized formulation of bipenalty method in contact-impact problems
Kolman, Radek ; González, J. A. ; Dvořák, Radim ; Kopačka, Ján ; Park, K.C.
Often, the finite element method together with direct time integration is used for modelling of contact-impact problems of bodies. For direct time integration, the implicit or explicit time stepping are gen-\nerally employed. It is well known that the time step size in explicit time integration is limited by the stability limit. Further, the trouble comes with the task of impact of bodies with different critical time step sizes for each body in contact. In this case, this numerical strategy based on explicit time stepping with the same time step size for both bodies is not effective and is not accurate due to the dispersion behaviour and spurious stress oscillations. For that reason, a numerical methodology, which allows independent time stepping for each body with its time step size, is needed to develop. In this paper, we introduce the localized variant of the bipenalty method in contact-impact problems with the governing equations derived based on the Hamilton’s principle. The localized bipenalty method is applied into the impact problems of bars as an one-dimensional problem. The definition of localized gaps is presented and applied into the full concept of the localized bipenalty method.
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How can crises generate a paradigm shift in political discourse on abortion?
Boonstra, Maryse ; González, María José (advisor) ; Stepanovic, Vera (referee)
Crises and their aftermath effects can have a detrimental impact on gender equality, specifically on Sexual and Reproductive Health Rights (SRHR), which concerns well-being in all matters related to the reproductive system (United Nations Population Fund, 2022), among which abortion services. Crises can contribute to a change in political discourse by exposing faults in the system which may motivate political actors to advocate for policy changes. The effects of crises have often been studied in relation to public opinion or financial impact. However, little is known about the effects of crises on SRHR and the political discourse surrounding this topic. This is despite the fact that SRHR have been recognised as a crucial policy field by organisations such as the UN (United Nations Sustainable Development Group, 2017). This thesis explores how crises can generate a paradigm shift in the political discourse on abortion by conducting a content analysis of the reports and debates on SRHR in the European Parliament during the post-crisis periods of the Eurocrisis and the COVID-19 crisis. The research finds an increased commitment of the European Parliament to abortion accessibility after the COVID-19 crisis. It also shows that this commitment was less present after the Eurocrisis. These findings indicate that...
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Inverse mass matrix for higher-order finite element method in linear free-vibration problems
Kolman, Radek ; González, J.G. ; Cimrman, Robert ; Kopačka, Ján ; Cho, S.S. ; Park, B.G.
In the paper, we present adirect inverse mass matrix in the higher-orderfinite element method forsolid mechanics. The direct inverse mass matrix is sparse, has the same structure as the consistent mass matrixand preserves the total mass. The core of derivation of the semi-discrete mixed form is based on the Hamilton’s principle of leastaction. The cardinal issue is finding the relationship between discretized velocities and discretized linear momentum. Finally, the simple formula for the direct inversemass matrix is presented as well as thechoice of density-weighted dual shape functions for linear momentum with respect to the displacement shape functionwith achoice of the lumping mass method for obtaining the correct and positive definitive velocity-linear momentum operator. The application of Dirichlet boundaryconditions into the direct inversemass matrix forafloating system is achieved usingthe projection operator. The suggested methodology is tested on a free-vibration problem of heterogeneous bar for different ordersof shape functions.
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Recent progress in numerical methods for explicit finite element analysis
Kolman, Radek ; Kopačka, Ján ; Gonzalez, J. ; Gabriel, Dušan ; Cho, S.S. ; Plešek, Jiří ; Park, K.C.
In this paper, a recent progress in explicit finite element analysis is discussed. Properties and behaviour of classical explicit time integration in finite element analysis of elastic wave propagation and contact-impact problems based on penalty method in contact-impact problems are summarized. Further, stability properties of explicit time scheme and the penalty method as well as existence of spurious oscillations in transient dynamics are mentioned. The novel and recent improving and progress in explicit analysis based on a local time integration with pullback interpolation for different local stable time step sizes, bipenalty stabilization for enforcing of contact constrains with preserving of stability limit for contact-free problems and using a direct inversion of mass matrix are presented. Properties of the employed methods are shown for one-dimensional cases of wave propagation and contact-impact problems.
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Flows along arch filaments observed in the GRIS `very fast spectroscopic mode'
Gonzalez Manrique, S. J. ; Denker, C. ; Kuckein, C. ; Pastor Yabar, A. ; Collados Vera, M. ; Verma, M. ; Balthasar, H. ; Diercke, A. ; Fischer, C.E. ; Gömöry, P. ; Bello González, N. ; Schlichenmaier, R. ; Cubas Armas, M. ; Berkefeld, T. ; Feller, A. ; Hoch, S. ; Hofmann, A. ; Lagg, A. ; Nicklas, H. ; Orozco Suárez, D. ; Schmidt, D. ; Schmid, W. ; Sigwarth, M. ; Sobotka, Michal ; Solanki, S.K. ; Soltau, D. ; Staude, J. ; Strassmeier, K.G. ; Volkmer, R. ; von der Lühe, O. ; Waldmann, T.A.
A new generation of solar instruments provides improved spectral, spatial, and temporal resolution, thus facilitating a better understanding of dynamic processes on the Sun. High-resolution observations often reveal multiple-component spectral line profiles, which provides information about the chromospheric velocity and magnetic fine structure. We observed an emerging flux region, including two small pores and an arch filament system, on 2015 April 17 with the "very fast spectroscopic mode" of the GREGOR Infrared Spectrograph (GRIS) situated at the 1.5-meter GREGOR solar telescope at Observatorio del Teide, Tenerife, Spain. We discuss this method of obtaining fast (one per minute) spectral scans of the solar surface and its potential to follow dynamic processes on the Sun. We demonstrate the performance of the "very fast spectroscopic mode" by tracking chromospheric high-velocity features in the arch filament system.
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An explicit time scheme with local time stepping for one-dimensional wave propagation in a bimaterial bar
Kolman, Radek ; Cho, S.S. ; Gonzalez, J.G. ; Park, K.C. ; Berezovski, A.
In this paper, we test a two-time step explicit scheme with local time stepping. The standard explicit time scheme in finite element analysis is not able to keep accuracy of stress distribution through meshes with different local Courant numbers for each finite element. The used two-time step scheme with the diagonal mass matrix is based on the modification of the central difference method with pullback interpolation. We present a numerical example of one-dimensional wave propagation in a bimaterial elastic bar. Based on numerical tests, the employed time scheme with pullback interpolation and local stepping technique is able to eliminate spurious oscillations in stress distribution in numerical modelling of shock wave propagation in heterogeneous materials.
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