48 research outputs found
Substance use genetics: Uncovering genes and testing gene-environment interplay
No full textContains fulltext :
237193.pdf (Publisher’s version ) (Open Access)Radboud University, 30 september 2021Promotores : Vink, J.M., Verweij, C.J.H. Co-promotor : Abdellaoui, A.465 p
Josephson effects in carbon nanotube mechanical resonators and graphene
No full textQuantum NanoscienceApplied Science
The calibration of the numerical wave model SWAN along the Petten Transect
No full textBecause of recent measurements and the first results of new calculations on the sea dike of Petten, Noord-Holland, the question has risen whether or not the sea dikes along the Dutch coast are high enough. A criterion which indicates whether or not a dike is high enough is the level above NAP which is exceeded by 2 % of the uprunning waves under conditions with a return period of ten thousand years (called 'survival conditions'). To calculate this level, wave parameters and the waterdepth at the toe of the dike must be obtained. The numerical wave model SWAN translates deep water wave conditions to shallow water wave conditions and so provides the wave parameters at the toe of the dike. The first aim of this study is to obtain a set of coefficients in SWAN which results in better predicted wave parameter values along the Petten transect. The second aim of this study is to obtain the 2 % run-up value of the Petten sea dike, under survival conditions, using the parameter values of Hsig and Tpeak at the toe of the dike, that are computed with the calibrated SWAN coefficients. First a sensitivity analysis has been carried out to determine which coefficients in the source terms of the actionbalance in SWAN are of great influence. These turned out to be the coefficients that control depth-induced breaking, the bottomfriction and the wave-wave interactions. Secondly these coefficients have been calibrated using measurements obtained from measuring points along the Petten transect during two storms in January 1995. After the calibration two kinds of verifications have been carried out: In the first kind of verification a comparison of SWAN results, obtained with the several calibration sets, has been made against the measurements which were also used in the calibration calculations. From this verification resulted one set of coefficients (called the best calibrated set) which did make the SWAN results come closer to the measurements than the original set of coefficients did. The second kind of verification was to investigate whether the best calibrated set of coefficients did improve the predictions of the wave parameters at four other times (at which independent observations were available). In three of the four cases the measurements were a little bit better approximated with the best calibrated set than with the original set of coefficients. Finally the wave parameters at the toe of the dike, obtained from SWAN calculations with the calibrated set of coefficients under survival conditions, have been used in the Van der Meer run-up formulas to calculate the 2% wave run-up. The resulting run-up turned out to be larger than the permitted value of the wave run-up for the Petten sea dike. The main conclusions are: - that, because the calibrated set produced only slightly better predictions of the wave parameters, the original set already predicts the wave parameters very well. - that, under conditions with a return period of ten thousand years, the Petten sea dike is lower than the 2% wave run-up, predicted by SWAN and the Van der Meer formulasHydraulic EngineeringCivil Engineering and Geoscience
Effect of mechanical resonance on Josephson dynamics
No full textWe study theoretically dynamics in a Josephson junction coupled to a mechanical resonator looking at the signatures of the resonance in dc electrical response of the junction. Such a system can be realized experimentally as a suspended ultraclean carbon nanotube brought in contact with two superconducting leads. A nearby gate electrode can be used to tune the junction parameters and to excite mechanical motion. We augment theoretical estimations with the values of setup parameters measured in one of the samples fabricated. We show that charging effects in the junction give rise to a mechanical force that depends on the superconducting phase difference and can excite the resonant mode. We develop a model that encompasses the coupling of electrical and mechanical dynamics. We compute the mechanical response (the effect of mechanical motion) in the regime of phase and dc voltage bias. We thoroughly investigate the regime of combined ac and dc bias where Shapiro steps are developed and reveal several distinct regimes characteristic for this effect. Our results can be immediately applied in the context of experimental detection of the mechanical motion in realistic superconducting nanomechanical devices.QN/Quantum NanoscienceApplied Science
Testing the prediction from sexual selection of a positive genetic correlation between human mate preferences and corresponding traits
No full textSexual selection can cause evolution in traits that affect mating success, and it has thus been implicated in the evolution of human physical and behavioural traits that influence attractiveness. We use a large sample of identical and nonidentical female twins to test the prediction from mate choice models that a trait under sexual selection will be positively genetically correlated with preference for that trait. Six of the eight preferences we investigated, i.e. height, hair colour, intelligence, creativity, exciting personality, and religiosity, exhibited significant positive genetic correlations with the corresponding traits, while the personality measures ‘easy going’ and ‘kind and understanding’ exhibited no phenotypic or genetic correlation between preference and trait. The positive results provide important evidence consistent with the involvement of sexual selection in the evolution of these human traits
