Impurity and spin effects on the magneto-spectroscopy of a THz-modulated nanostructure

We present a grid-free DFT model appropriate to explore the time evolution of electronic states in a semiconductor nanostructure. The model can be used to investigate both the linear and the nonlinear response of the system to an external short-time perturbation in the THz regime. We use the model to study the effects of impurities on the magneto-spectroscopy of a two-dimensional electron gas in a nanostructure excited by an intense THz radiation. We do observe a reduction in the binding energy of the impurity with increasing excitation strength, and at a finite magnetic field we find a slow onset of collective spin-oscillations that can be made to vanish with a stronger excitation.Comment: LaTeX,10 pages with 11 embedded postscript figure

Patient-Specific Computational Modeling of Upper Extremity Arteriovenous Fistula Creation: Its Feasibility to Support Clinical Decision-Making

<div><h3>Introduction</h3><p>Inadequate flow enhancement on the one hand, and excessive flow enhancement on the other hand, remain frequent complications of arteriovenous fistula (AVF) creation, and hamper hemodialysis therapy in patients with end-stage renal disease. In an effort to reduce these, a patient-specific computational model, capable of predicting postoperative flow, has been developed. The purpose of this study was to determine the accuracy of the patient-specific model and to investigate its feasibility to support decision-making in AVF surgery.</p> <h3>Methods</h3><p>Patient-specific pulse wave propagation models were created for 25 patients awaiting AVF creation. Model input parameters were obtained from clinical measurements and literature. For every patient, a radiocephalic AVF, a brachiocephalic AVF, and a brachiobasilic AVF configuration were simulated and analyzed for their postoperative flow. The most distal configuration with a predicted flow between 400 and 1500 ml/min was considered the preferred location for AVF surgery. The suggestion of the model was compared to the choice of an experienced vascular surgeon. Furthermore, predicted flows were compared to measured postoperative flows.</p> <h3>Results</h3><p>Taken into account the confidence interval (25^th and 75^th percentile interval), overlap between predicted and measured postoperative flows was observed in 70% of the patients. Differentiation between upper and lower arm configuration was similar in 76% of the patients, whereas discrimination between two upper arm AVF configurations was more difficult. In 3 patients the surgeon created an upper arm AVF, while model based predictions allowed for lower arm AVF creation, thereby preserving proximal vessels. In one patient early thrombosis in a radiocephalic AVF was observed which might have been indicated by the low predicted postoperative flow.</p> <h3>Conclusions</h3><p>Postoperative flow can be predicted relatively accurately for multiple AVF configurations by using computational modeling. This model may therefore be considered a valuable additional tool in the preoperative work-up of patients awaiting AVF creation.</p> </div

Optical creation of vibrational intrinsic localized modes in anharmonic lattices with realistic interatomic potentials

Using an efficient optimal control scheme to determine the exciting fields, we theoretically demonstrate the optical creation of vibrational intrinsic localized modes (ILMs) in anharmonic perfect lattices with realistic interatomic potentials. For systems with finite size, we show that ILMs can be excited directly by applying a sequence of femtosecond visible laser pulses at THz repetition rates. For periodic lattices, ILMs can be created indirectly via decay of an unstable extended lattice mode which is excited optically either by a sequence of pulses as described above or by a single picosecond far-infrared laser pulse with linearly chirped frequency. In light of recent advances in experimental laser pulse shaping capabilities, the approach is experimentally promising.Comment: 20 pages, 7 eps figures. Accepted, Phys. Rev.

Bendable, low-loss Topas fibers for the terahertz frequency range

We report on a new class of polymer photonic crystal fibers for low-loss guidance of THz radiation. The use of the cyclic olefin copolymer Topas, in combination with advanced fabrication technology, results in bendable THz fibers with unprecedented low loss and low material dispersion in the THz regime.We demonstrate experimentally how the dispersion may be engineered by fabricating both high- and low-dispersion fibers with zero-dispersion frequency in the regime 0.5-0.6 THz. Near-field, frequencyresolved characterization with high spatial resolution of the amplitude and phase of the modal structure proves that the fiber is single-moded over a wide frequency range, and we see the onset of higher-order modes at high frequencies as well as indication of microporous guiding at low frequencies and high porosity of the fiber. Transmission spectroscopy demonstrates low-loss propagation (< 0.1 dB/cm loss at 0.6 THz) over a wide frequency range.Imaging Science and TechnologyApplied Science

EFL Academic writing. What should Dutch business communication students learn?

Contains fulltext : 155467.pdf (publisher's version ) (Open Access)Many Dutch university students are expected to read and write academic research papers in English. In this article, we discuss a number of areas of EFL academic writing that are relevant for first-year Dutch business communication students. These students need to become familiar with quantitative research in the field of international business communication (corpus analyses, experiments, surveys) and with the English conventions for reporting such research. The relevant areas of EFL academic writing include the conventions of empirical research articles and research posters in terms of structure, phrasing, tense use, expressing caution, and referencing. We will illustrate our discussion with examples of exercises from a course we have designed to enable students to practise their skills in the various areas. We also present the results of a survey among our students regarding their experience of the course and student exam scores showing how well they have mastered various aspects of academic writing discussed in the course.Van Schools tot Scriptie II. Een colloquium over universitair taalvaardigheidonderwijs, 04 juli 201

The Netherlands

Item does not contain fulltextThe Netherlands can be regarded as a multilingual society, in which the majority – and official – language of the Netherlands, Dutch, is used in different everyday contexts alongside immigrant languages such as Arabic and Turkish and foreign languages such as French and German. In the northern province of Fryslân, the regional language Frisian, which is recognized officially by law, is widely used in society alongside Dutch. Dutch language policy through the years can be seen to be cognizant of the cultural diversity and multilingualism in Dutch society. In education, while English is compulsory as the first foreign language in primary and secondary education, other foreign languages are offered as options too. In the province of Fryslân, Frisian as an additional language to English is compulsory at primary school and the first two years of secondary school, although schools may opt out of the latter obligation if there is an insufficient number of Frisian teachers available. While the initiative to offer minority language education has ceased, the minority languages Turkish and Arabic are offered as optional foreign languages in secondary education. On the whole, this would suggest that Dutch language policy follows Europe’s “one-plus-two” foreign language policy, a language policy which also aims to promote intercultural exchange in a multilingual society and multilingual world. In the course of this chapter, we will consider to what extent this European ideal is achieved in educational practice