Institution
Open University in the Netherlands
Education•Heerlen, Netherlands•
About: Open University in the Netherlands is a education organization based out in Heerlen, Netherlands. It is known for research contribution in the topics: Educational technology & Computer science. The organization has 407 authors who have published 663 publications receiving 13522 citations.
Topics: Educational technology, Computer science, Higher education, Collaborative learning, Learning analytics
Papers published on a yearly basis
Papers
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TL;DR: Caution should still be exercised when new sunscreens are developed and research that includes sunscreen NP stabilization, chronic exposures, and reduction of NPs' free-radical production should receive full attention.
Abstract: Sunscreens are used to provide protection against adverse effects of ultraviolet (UV)B (290-320 nm) and UVA (320-400 nm) radiation. According to the United States Food and Drug Administration, the protection factor against UVA should be at least one-third of the overall sun protection factor. Titanium dioxide (TiO2) and zinc oxide (ZnO) minerals are frequently employed in sunscreens as inorganic physical sun blockers. As TiO2 is more effective in UVB and ZnO in the UVA range, the combination of these particles assures a broad-band UV protection. However, to solve the cosmetic drawback of these opaque sunscreens, microsized TiO2 and ZnO have been increasingly replaced by TiO2 and ZnO nanoparticles (NPs) (<100 nm). This review focuses on significant effects on the UV attenuation of sunscreens when microsized TiO2 and ZnO particles are replaced by NPs and evaluates physicochemical aspects that affect effectiveness and safety of NP sunscreens. With the use of TiO2 and ZnO NPs, the undesired opaqueness disappears but the required balance between UVA and UVB protection can be altered. Utilization of mixtures of micro- and nanosized ZnO dispersions and nanosized TiO2 particles may improve this situation. Skin exposure to NP-containing sunscreens leads to incorporation of TiO2 and ZnO NPs in the stratum corneum, which can alter specific NP attenuation properties due to particle-particle, particle-skin, and skin-particle-light physicochemical interactions. Both sunscreen NPs induce (photo)cyto- and genotoxicity and have been sporadically observed in viable skin layers especially in case of long-term exposures and ZnO. Photocatalytic effects, the highest for anatase TiO2, cannot be completely prevented by coating of the particles, but silica-based coatings are most effective. Caution should still be exercised when new sunscreens are developed and research that includes sunscreen NP stabilization, chronic exposures, and reduction of NPs' free-radical production should receive full attention.
710 citations
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TL;DR: A team is more than a group of people in the same space, physical or virtual as discussed by the authors, and increasing attention has been devoted to the social bases of cognition, taking into consideration how...
Abstract: A team is more than a group of people in the same space, physical or virtual. In recent years, increasing attention has been devoted to the social bases of cognition, taking into consideration how ...
677 citations
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01 Jan 2011TL;DR: Manouselis, N., Drachsler, H., Vuorikari, R., Hummel, H. K., & Koper, R. (2011).
Abstract: Manouselis, N., Drachsler, H., Vuorikari, R., Hummel, H. G. K., & Koper, R. (2011). Recommender Systems in Technology Enhanced Learning. In P. B. Kantor, F. Ricci, L. Rokach, & B. Shapira (Eds.), Recommender Systems Handbook (pp. 387-415). Berlin: Springer.
360 citations
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TL;DR: Cognitive load theory has progressed and advanced rapidly over the last few years as discussed by the authors, and contributions to the 3rd International Cognitive Load Theory Conference (2009), Heerlen, The Netherlands.
Abstract: Over the last few years, cognitive load theory has progressed and advanced rapidly. The articles in this special issue, which document those advances, are based on contributions to the 3rd International Cognitive Load Theory Conference (2009), Heerlen, The Netherlands. The articles of this special issue on cognitive load theory discuss new conceptualizations of the different categories of cognitive load, an integrated research perspective of process-oriented and cognitive load approaches to collaborative learning, an integrated research perspective of cognitive and social-cognitive approaches to example-based learning, and a specification of the theory focusing on the acquisition of generalized knowledge structures as a means to facilitate flexible problem-solving skills. This article provides a short introduction to the theory, discusses some of its recent advances, and provides an overview of the contributions to this issue.
305 citations
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TL;DR: A conceptual framework that provide guidelines for choosing maintenance function performance indicators is proposed and seeks to align maintenance objectives with manufacturing and corporate objectives, and provides a link between the maintenance objectives, maintenance process/efforts and maintenance results.
293 citations
Authors
Showing all 432 results
Name | H-index | Papers | Citations |
---|---|---|---|
Peter Nijkamp | 97 | 2407 | 50826 |
Paul A. Kirschner | 82 | 545 | 33626 |
Fred Paas | 78 | 307 | 31331 |
Jeroen J. G. van Merriënboer | 70 | 374 | 28154 |
Matthias Jarke | 62 | 595 | 16345 |
Martin Valcke | 54 | 421 | 13259 |
Tamara van Gog | 52 | 204 | 10832 |
Rob Koper | 50 | 280 | 8773 |
Carolien Kroeze | 49 | 240 | 11023 |
Henny P. A. Boshuizen | 46 | 124 | 9654 |
Beatrice van der Heijden | 46 | 274 | 9353 |
Lilian Lechner | 44 | 189 | 6408 |
Marcus Specht | 41 | 322 | 6375 |
Stefan C. Dekker | 39 | 127 | 5668 |
Liesbeth Kester | 38 | 121 | 4346 |