Proximity Induced Superconductivity in CdTe-HgTe Core-Shell Nanowires

In this letter we report on proximity superconductivity induced in CdTe-HgTe core-shell nanowires, a quasi-one-dimensional heterostructure of the topological insulator HgTe. We demonstrate a Josephson supercurrent in our nanowires contacted with superconducting Al leads. The observation of a sizable $I_c R_n$ product, a positive excess current and multiple Andreev reflections up to fourth order further indicate a high interface quality of the junctions.Comment: Accepted for publication in Nano Letter

Approximated and User Steerable tSNE for Progressive Visual Analytics

Progressive Visual Analytics aims at improving the interactivity in existing analytics techniques by means of visualization as well as interaction with intermediate results. One key method for data analysis is dimensionality reduction, for example, to produce 2D embeddings that can be visualized and analyzed efficiently. t-Distributed Stochastic Neighbor Embedding (tSNE) is a well-suited technique for the visualization of several high-dimensional data. tSNE can create meaningful intermediate results but suffers from a slow initialization that constrains its application in Progressive Visual Analytics. We introduce a controllable tSNE approximation (A-tSNE), which trades off speed and accuracy, to enable interactive data exploration. We offer real-time visualization techniques, including a density-based solution and a Magic Lens to inspect the degree of approximation. With this feedback, the user can decide on local refinements and steer the approximation level during the analysis. We demonstrate our technique with several datasets, in a real-world research scenario and for the real-time analysis of high-dimensional streams to illustrate its effectiveness for interactive data analysis

Cannabis legalisation and testing for cannabis use in safety- and risk-sensitive environments

The legalisation of cannabis by the High Court of South Africa, which was confirmed by the Constitutional Court, imposes challenges to occupational medical practitioners acting as medical review officers in compliance testing and fit-for-service medical examinations. The lipophilic character of the psychoactive component of cannabis, delta-9-tetrahydrocannabinol (Δ9-THC), and its prolonged elimination half-life, create challenges for the ethically and scientifically correct management of the legal use of cannabis in risk-sensitive environments. Important issues to consider in testing for cannabis use are: the stance of ‘zero tolerance’; screening and confirmation cut-off concentrations; and the bio-matrices used for testing. Constitutional rights relate to privacy, freedom, autonomy, freedom of religion and the equal enjoyment of rights and privileges, which must be balanced against the health and safety of others

Unusual cause of mechanical ileus: abdominal cocoon syndrome

A 38-year-old black male patient was admitted with diarrhea and nausea over two days and aggravating pain in the meso- and epigastium that resolved after urination. He had no surgical history and only an episode of pulmonary tuberculosis five years earlier, for which he was properly treated. Physical examination revealed a tender and distended abdomen with clangorous sounds. His temperature was 36.1°C. Routine laboratory blood analyses were normal. An abdominal ultrasound revealed diffuse distention of the small intestine. A computed tomography (CT) scan showed a conglomerate of dilated small bowel loops in the meso- and hypogastrium, suggestive for a supravesical mechanical small bowel obstruction. Peritoneal thickening was seen in the right epigastrium (Figure A, white arrow). An explorative laparoscopy revealed a whitish, thickened membrane encapsulating the small bowels as a ‘cocoon’ (Figure B). Extensive adhesiolysis released an intestinal kinking in the lower abdomen, just above the bladder. No resection was needed. Histopathology of the membrane showed fibrocollagenous tissue with mixed inflammatory infiltrate

Spin injection across magnetic/non-magnetic interfaces with finite magnetic layers

We have reconsidered the problem of spin injection across ferromagnet/non-magnetic-semiconductor (FM/NMS) and dilute-magnetic-semiconductor/non-magnetic-semiconductor interfaces, for structures with \textit{finite} magnetic layers (FM or DMS). By using appropriate physical boundary conditions, we find expressions for the resistances of these structures which are in general different from previous results in the literature. When the magnetoresistance of the contacts is negligible, we find that the spin-accumulation effect alone cannot account for the $d$ dependence observed in recent magnetoresistance data. In a limited parameter range, our formulas predict a strong $d$ dependence arising from the magnetic contacts in systems where their magnetoresistances are sizable.Comment: 6 pages, 3 eps figs. (extended version- new title + two new figures added

How does Internationalisation affect the productivity of R&D activities in large innovative firms? A conditional nonparametric investigation

This work explores the relationship between multinational R&D and innovation productivity among top corporate knowledge and R&D producers by adopting a twofold concept of internationalisation: (1) the firm’s degree of R&D internationalisation, and (2) the firm’s geographic diversification. We model the patent production process with an appropriate and robust conditional Data Envelopment Analysis (DEA) estimator, using a unique database of firms that matches financial indicators and patent information. Our results reinforce the fundamental role of internationalisation in the knowledge production process when the internationalisation process is properly and strategically managed. We interpret our empirical evidence through the theoretical lens of the learning theory of internationalisation, and we postulate that a high R&D intensity is a key driver to overcoming the challenges of internationalisation

A navigation aid for the visually impaired

The explosion of new technologies in recent times has created many as yet unexplored possibilities in the area of assistive technology. Assistive technology may be thought of as any technology that alleviates the affects of an impairment, disability or handicap. One of the greatest challenges facing designers of assistive technologies is to accurately define the user requirements. The background research chapter of this report attempts to define the user requirements for a navigation aid that can be used any person, regardless of visual ability, both through literature surveys and through dialogue with potential end users. The conclusions drawn from this research are used as a basis for an investigation into possible technological solutions, culminating in a technical summary. Subsequently, the design and implementation of a software package capable of providing environmental information and navigational suggestions is discussed in the final chapters The package is designed to be flexible enough to act as a basis for further research and eventual implementation of a fully functioning navigation aid

The incidence of associated fractures of the upper limb in fractures of the radial head

Radial head fractures are common injuries. In American publications, one-third of the patients with these fractures have been shown to have associated injuries. The aim of this retrospective study is to describe the epidemiology of radial head fractures and associated fractures of the ipsilateral upper extremity in a European population. This study describes the epidemiology of radial head and associated fractures of the upper extremity in a Dutch population by a retrospective radiographic review of all patients with a radial head fracture between 1 January 2006 and 1 July 2007. A total of 147 radial head fractures were diagnosed in 145 patients. The incidence in the general population was 2.5 per 10.000 per year. The average age was 45.9 (SD 17.3) years and male–female ratio was 2:3. The mean age of males was significantly lower (37.1, SD 14.2 years) than of women (53.9, SD 16.4 years). Associated fracture of the upper extremity was found in 10.2%. Coronoid fractures were most common (4.1%). Associated upper limb fractures in patients with a radial head fracture are common in the European population. It is of clinical importance to suspect associated lesions and to perform a thorough physical examination and additional radiological examination on demand

Lower and upper bounds for the Rayleigh conductivity of a perforated plate

International audienceLower and upper bounds for the Rayleigh conductivity of a perforation in a thick plate are usually derived from intuitive approximations and by physical reasoning. This paper addresses a mathematical justification of these approaches. As a byproduct of the rigorous handling of these issues, some improvements to previous bounds for axisymmetric holes are given as well as new estimates for inclined perforations. The main techniques are a proper use of the variational principles of Dirichlet and Kelvin in the context of Beppo-Levi spaces. The derivations are validated by numerical experiments in the two-dimensional axisymmetric case and the full three-dimensional one