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Implementing U-prove extension protocols in Magma
No full textImplementing pairings seems easier than it actually is. The aim of this research was to implement the extension protocols of U-prove, designed by Erik Weitenberg, which contain a pairing. The ambition was to find out how difficult it is to implement a pairing. Another reason was to determine whether the extension protocols are applicable and not only work on paper. The implementations are executed in Magma. To understand how Magma works basic protocols are implemented. The theory needed for the implementations is explained. Both extension protocols are successfully implemented with the suitable example that is found. The obstacles that need to be overcome, for this single example, show the difficulty of implementing a pairing.
Exploring the AdS CFT correspondence by looking at black hole entropy
No full textDe begeleider en/of auteur heeft geen toestemming gegeven tot het openbaar maken van de scriptie.
The supervisor and/or the author did not authorize public publication of the thesis.
Reversible Photochemical Control of Singlet Oxygen Generation Using Diarylethene Photochromic Switches
No full textReversible noninvasive control over the generation of singlet oxygen is demonstrated in a bicomponent system comprising a diarylethene photochromic switch and a porphyrin photosensitizer by selective irradiation at distinct wavelengths. The efficient generation of singlet oxygen by the photosensitizer is observed when the diarylethene unit is in the colorless open form. Singlet oxygen generation is not observed when the diarylethene is converted to the closed form. Irradiation of the closed form with visible light (>470 nm) leads to full recovery of the singlet oxygen generating ability of the porphyrin sensitizer.
Electrochemical Deuteration of Metastable MgTi Alloys: An Effective Way to Inhibit Phase Segregation
No full textElectrochemical deuteration of metastable Mg-Ti alloys is studied. To investigate the dynamics of deuterium atoms in the crystal host, the as-prepared hydrides are examined by means of NMR spectroscopy. Remarkably the host compound, which phase segregates upon gas phase deuteration at high temperatures, preserves its original structure during low temperature electrochemical deuteration. Deuterium atoms exchange dynamically between Mg-rich and Ti-rich sites.
Your bytes are your babies. Protect what's precious, keep IT safe
No full textEen gesprek met Gerrit van Dijk (Administratieve Informatie Voorziening) en Willemieke Baan (Donald Smits Centrum voor Informatie Technologie) over de Risk Awareness-campagne Keep IT safe
Read all about it!
No full textHet onderzoek in dit proefschrift is uitgevoerd binnen de interventie ‘Meer Taal, Meer Kans’. Deze interventie is vanaf 2009 uitgevoerd in Leeuwarden en Rotterdam. De doelgroep bestond uit Antilliaanse peuters en hun moeders. De doelen van dit programma waren om de opvattingen van de deelnemende Antilliaanse moeders met betrekking tot hun eigen invloed op de taalontwikkeling van hun kind positiever te maken, om de positieve en warme interactie tussen moeder en kind te stimuleren en om de thuistaalomgeving in zowel het Papiaments als het Nederlands te verrijken.
Kort gezegd waren de voorleesopvattingen van de deelnemende Antilliaanse moeders positief en slechts op een paar onderdelen minder positief dan die van een contrastgroep van hoogopgeleide Nederlandse moeders. Noch de voorleesopvattingen, noch de wederkerigheid kunnen echter omschreven worden als stabiele constructen. Als er naar de individuele scores wordt gekeken is er sprake van een sterke intra- en interindividuele variabiliteit. Wat betreft de tweetaligheid valt op dat de meeste gezinnen een voorkeur hadden voor de Nederlandse taal, terwijl de interventie een tweetalig karakter had.
In de combinatie van de genoemde constructen, zijn er statistische relaties gevonden tussen de hoeveelheid deelname in de interventie, positieve interactie en het aandeel van het kind in het gesprek. Ook bleek dat kinderen uit gezinnen met meer huisbezoeken meer lexicale diversiteit toonden. Hoewel beperkingen met betrekking tot de context en het onderzoeksontwerp ernstige gevolgen hadden voor de interpretatie, blijkt wel dat het onderzoek interessante combinaties van groeps- en procesgegevens opgeleverd heeft. Dit kan toegepast kan worden in diverse (interventie)omgevingen.
The research setting of this dissertation was the intervention programme ‘More Languages, More Opportunities’, which was executed from 2009 onwards in Leeuwarden and Rotterdam. The target group consisted of Antillean toddlers and their mothers. The aims of the intervention were to enhance the beliefs of the participating Antillean mothers towards their own influence in child language development, to stimulate the positive, warm interaction between mother and child, and to improve the home linguistic environment in both Papiamentu and Dutch.
In short, the parental reading beliefs of the participating Antillean mothers were positive and only partially less positive than a contrast group of highly educated Dutch mothers. The mutuality of the interaction is also generally positive and well-balanced. Although a global trend (in- or decrease) over time cannot be detected in the group data, the individual scores show strong intra- and inter-individual variability. With regard to the language use, in spite of the bilingual nature of the intervention, most families showed a clear preference for the Dutch language.
When the constructs were combined, statistical associations were found between the amount of participation in the intervention, positive affection and the proportion of the conversation of the child. In addition, children from families who took part in more home visits were more lexically diverse. Although several context and research design conditions impeded the interpretation of the outcomes, the study demonstrated the importance of combining group and process data, which can be applied in many (intervention) settings.
Direct visualization of magnetoelectric domains
No full textThe coupling between the magnetic and electric dipoles in multiferroic and magnetoelectric materials holds promise for conceptually novel electronic devices. This calls for the development of local probes of the magnetoelectric response, which is strongly affected by defects in magnetic and ferroelectric ground states. For example, multiferroic hexagonal rare earth manganites exhibit a dense network of boundaries between six degenerate states of their crystal lattice, which are locked to both ferroelectric and magnetic domain walls. Here we present the application of a magnetoelectric force microscopy technique that combines magnetic force microscopy with in situ modulating high electric fields. This method allows us to image the magnetoelectric response of the domain patterns in hexagonal manganites directly. We find that this response changes sign at each structural domain wall, a result that is corroborated by symmetry analysis and phenomenological modelling, and provides compelling evidence for a lattice-mediated magnetoelectric coupling. The direct visualization of magnetoelectric domains at mesoscopic scales opens up explorations of emergent phenomena in multifunctional materials with multiple coupled orders.
Structural and mechanistic insights into prokaryotic energy-coupling factor transporters
No full textEnergy-coupling factor (ECF) transporters belong to the ATP-binding cassette (ABC)-transporter family and mediate the uptake of essential micronutrients in many prokaryotic species. Two crystal structures of bacterial ECF transporters have recently been obtained and suggest that transport involves an unprecedented re‑orientation of a membrane protein in the lipid bilayer during catalysis. In this Progress article, I present the new structural insights, discuss a testable model for the transport mechanism and consider the more general implications of these findings for our understanding of membrane transporters.
The effects of trap fisheries on the populations of Caribbean spiny lobster and reef fish species at the Saba Bank
No full textDe begeleider en/of auteur heeft geen toestemming gegeven tot het openbaar maken van de scriptie.
The supervisor and/or the author did not authorize public publication of the thesis.