408 research outputs found
Mediating Africa Today Through the Cinema of Yole!Africa:A Conversation Between Matthias De Groof and Petna Ndaliko Katondolo
No full textThis conversation pursues the question of how Africa can be mediated. Through a discussion between the filmmakers Matthias De Groof and Petna Ndaliko Katondolo about their respective works produced at Yolé!Africa—Ndaliko Katondolo’s films Mahere (2023) and Kapita (2017) on the one hand, and De Groof’s film Tantalum (produced by Ndaliko Katondolo, 2024) on the other—a light will be shed on the importance of media-geology and geo-mythology in relation to the ways in which Africa is mediated. YoléAfrica is an educational center located in Goma, Democratic Republic of Congo, which serves as an empowering hub for film activism, as well as provides a platform for community development through its arts education and agro-liberation initiatives (it houses Yolé!Ekolojia). The center organizes the annual Ishango Encounter, an international film festival, and otherwise gathers Congolese activists and filmmakers to create awareness and healing through film
Fast and Alfvén waves driven by azimuthal footpoint motions - II. Random driver
Get PDFThe excitation of Alfven and fast magneto-acoustic waves in coronal loops driven by footpoint motions is studied in linear, ideal MHD. The analysis is restricted to azimuthally polarized footpoint motions so that only Alfven waves are directly excited to couple to fast magneto-acoustic waves at later times. In the companion paper De Groof et al. (2002) (hereafter referred to as Paper I), the behaviour of the MHD waves is studied in case of a monochromatic driver. In the present study, the effects of a more realistic random driver are investigated. First, we consider loops of equal length and width in order to limit the number of quasi-modes in the frequency range of the driver so that the influence of quasi-modes in the system can easily be detected. In contrast to the single resonant surface which was found in case of a periodic driver (see Paper I), a random pulse train excites a variety of resonant Alfven waves and consequently the small length scales built up are spread over the whole width of the loop. The specific effects of the quasi-modes are not so easily recognized as for radial footpoint motions (De Groof & Goossens 2000) since the resonances corresponding to directly and indirectly excited Alfven waves are mixed together. In the second part of the paper, longer loops are considered. Since more quasi-modes are involved, the resonant surfaces are more numerous and widely spread throughout the whole loop volume. On the other hand, it takes more time for the MHD waves to cross the loop and to form standing waves. Nevertheless this negative effect does not have too much impact since the simulations show that after a small time interval, resonant surfaces are created all over the loop, with length scales which are short enough for effective dissipation.status: Publishe
Toll-like receptor 3 increases antigen-presenting cell responses to a pro-apoptotic stimulus, yet does not contribute to systemic lupus erythematosus genetic susceptibility
No full textThis work was supported by grants from the WELBIO, Fonds National de la Recherche Scientifique and Fonds
Spéciaux pour la Recherche (Communauté française de Belgique), and by Instituto de Salud Carlos III
(grants PI11/01048 and RD12/0009/0008 that are partially financed by the European Regional Development Fund of the European Union).De Groof, A., Ducreux, J., Vidal-Bralo, L., Tyteca, D., Galant, C., Marot, L., Coulie, P.G., van den Eynde, B.J., Rodriguez-Martinez, L., Santos, M.J., Suarez, A., Carreira, P., Marchini, M., Gonzàlez, A., Houssiau, F.A., Lauwerys, B.R
Commercial integration and fiscal policy in interdependent, financially integrated two-sector economies with real and nominal wage rigidity
Get PDFMacroeconomic Models;Economic Integration;international economics
The twin-debt problem in an interdependent world
Get PDFGovernment Expenditure;External Debt;monetary economics
Aspects of goods market integration: A two-country-two-sector analysis
Get PDFEconomic Integration;Fiscal Policy;Models
Fast and Alfvén waves driven by azimuthal footpoint motions - I. Periodic driver
Get PDFThe excitation of Alfven and fast magneto-acoustic waves in coronal loops driven by footpoint motions is studied in linear, ideal MHD. The analysis is restricted to azimuthally polarized footpoint motions so that only Alfven waves are directly excited which couple to fast magneto-acoustic waves at later times. In the present study a periodic driver is applied at one end of the loop. The effects of a more realistic random driver are studied in the companion paper De Groof & Goossens (2002) (hereafter referred to as Paper II). The first part of the paper is devoted to the study of resonant absorption and phase-mixing in the absence of coupling (azimuthal wavenumber k(y) = 0). Since the density varies across the loop, resonances occur at the magnetic surfaces where the driving frequency equals the local Alfven frequency. In a second part where Alfven waves with k(y) not equal 0 coupling to fast waves are taken into account, we find that the behaviour of the MHD waves is strongly dependent on the driving frequency omega(d). Especially driving frequencies equal to a quasi-mode frequency seem to make the difference. The fast waves excited in these cases are global oscillations of the system and form quasi-modes as they are damped through the resonant coupling with Alfven modes. Since these resonances occur at the same location where the original Alfven wave peaks, the resonant peak is further amplified. While in most cases coupling has a negative effect on the growth of the directly excited Alfven waves, driving with a quasi-mode frequency leads to a faster growth of the resonant peaks and a more efficient decrease in length scales than in the uncoupled case.status: Publishe
Financial integration and fiscal policy in interdependent two-sector economies with real and nominal wage rigidity
Get PDFEconomic Integration;Models;econometrics
Quantitative assessment of random field models in finite element buckling analyses of composite cylinders
No full textLarge scatter characterizes the collapse load of thin-walled structures due to their imperfection sensitivity. Random fields can be used to include imperfections in a finite element model, which can highly increase the credibility of the finite element (FE) model. Principal component analysis (PCA) and analytical covariance functions are matched to available correlation information of geometrical imperfection measurements. The random fields are realized by Karhunen-Lo`eve expansion combined with Monte Carlo methods. The results of the different covariance models are compared with the deterministic collapse loads of the measured imperfections in the FE-model. This approach isolates the effect of the different covariance models from other inaccuracies such as boundary conditions, loading imperfections, etc. The results show that random fields can be used to improve predictions and the understanding of the structural behavior of thin-walled structures, especially when these predictions are based on imperfection data, using PCA. Caution is recommended when using analytical covariance functions since they may fail to capture the complete behavior of the structure
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