Suppression of decoherence in a graphene monolayer ring

The influence of high magnetic fields on coherent transport is investigated. A monolayer graphene quantum ring is fabricated and the Aharonov-Bohm effect is observed. For increased magnitude of the magnetic field higher harmonics appear. This phenomenon is attributed to an increase of the phase coherence length due to reduction of spin flip scattering

PFTijah: text search in an XML database system

This paper introduces the PFTijah system, a text search system that is integrated with an XML/XQuery database management system. We present examples of its use, we explain some of the system internals, and discuss plans for future work. PFTijah is part of the open source release of MonetDB/XQuery

Berry Phase Transition in Twisted Bilayer Graphene

The electronic dispersion of a graphene bilayer is highly dependent on rotational mismatch between layers and can be further manipulated by electrical gating. This allows for an unprecedented control over electronic properties and opens up the possibility of flexible band structure engineering. Here we present novel magnetotransport data in a twisted bilayer, crossing the energetic border between decoupled monolayers and coupled bilayer. In addition a transition in Berry phase between pi and 2pi is observed at intermediate magnetic fields. Analysis of Fermi velocities and gate induced charge carrier densities suggests an important role of strong layer asymmetry for the observed phenomena.Comment: 20 pages main paper + 10 pages supporting informatio

Sound ranking algorithms for XML search

Ranking algorithms for XML should reflect the actual combined content and structure constraints of queries, while at the same time producing equal rankings for queries that are semantically equal. Ranking algorithms that produce different rankings for queries that are semantically equal are easily detected by tests on large databases: We call such algorithms not sound. We report the behavior of different approaches to ranking content-and-structure queries on pairs of queries for which we expect equal ranking results from the query semantics. We show that most of these approaches are not sound. Of the remaining approaches, only 3 adhere to the W3C XQuery Full-Text standard

IR area array status

Leading array technologies are defined and the status of HgCdTe hybrid focal plane development is reported. The liquid phase epitaxy system for HgCdTe production is also discussed

The Impact of Physical Abuse & Exposure to Parental IPV on Young Adolescents in Poland: a Clinical Assessment and Comparison of Psychological Outcomes

This study explores characteristics of youth who experienced domestic violence in Poland. Specifically, young adolescents who were victims of physical abuse perpetrated by parents and young adolescents who were exposed to parental intimate partner violence (IPV) were studied to determine whether the groups had similar or different psychological outcomes. Additionally, the study looked into ways by which these youth cope with stress and demonstrate self-efficacy. Data were collected from 90 youth aged 11 to 14 years using quota sampling; 30 were victims of physical abuse, 30 were victims of exposure to parental IPV, and 30 were members of a comparison group. Parents gave written consent for participation while adolescents provided verbal assent and subsequently completed questionnaires. Analyses revealed that adolescents who experienced physical abuse showed higher levels of trait anxiety and outwardly directed anger, and a lower sense of self-efficacy, than adolescents exposed to IPV. In contrast, those exposed to parental IPVexhibited a lower level of trait anxiety, a higher level of inwardly directed anger, and a greater sense of strength and perseverance. No statistically significant differences existed between groups in terms of coping with stress. The findings suggests that adolescents experiencing different types of family violence victimizationmay have different outcomes, which could call for differential treatment. Future research should more closely examine victims of physical abuse and exposure to IPV in Poland to see if findings hold. This would help clinicians recognize outcomes associated with different experiences and tailor appropriate strategies

Unconventional magnetism in all-carbon nanofoam

We report production of nanostructured carbon foam by a high-repetition-rate, high-power laser ablation of glassy carbon in Ar atmosphere. A combination of characterization techniques revealed that the system contains both sp2 and sp3 bonded carbon atoms. The material is a novel form of carbon in which graphite-like sheets fill space at very low density due to strong hyperbolic curvature, as proposed for ?schwarzite?. The foam exhibits ferromagnetic-like behaviour up to 90 K, with a narrow hysteresis curve and a high saturation magnetization. Such magnetic properties are very unusual for a carbon allotrope. Detailed analysis excludes impurities as the origin of the magnetic signal. We postulate that localized unpaired spins occur because of topological and bonding defects associated with the sheet curvature, and that these spins are stabilized due to the steric protection offered by the convoluted sheets.Comment: 14 pages, including 2 tables and 7 figs. Submitted to Phys Rev B 10 September 200

Medical consent for a minor - an alternative proposal

Under current South African law, in terms of Child Care Act 74 of 1983,1 consent for elective surgery, HIV testing and therapy can only be given by the biological mother, married father or legal guardian of a minor. Where the consent of a parent or legal guardian cannot be obtained, permission for a medical procedure must be sought from the Minister of Social Development if in the opinion of a medical practitioner the procedure is necessary, i.e. consent by proxy. While we can accept that the intention of the law is to protect the welfare of the child, we find that this prejudices those patients requiring consent via the social service department. This procedure has in the past often led to delays and/or cancellations of the intended surgery or institution of appropriate therapy. It is a protracted pathway and at times a frustrating endeavour