Silicon and III-V compound nanotubes: structural and electronic properties

Unusual physical properties of single-wall carbon nanotubes have started a search for similar tubular structures of other elements. In this paper, we present a theoretical analysis of single-wall nanotubes of silicon and group III-V compounds. Starting from precursor graphene-like structures we investigated the stability, energetics and electronic structure of zigzag and armchair tubes using first-principles pseudopotential plane wave method and finite temperature ab-initio molecular dynamics calculations. We showed that (n,0) zigzag and (n,n) armchair nanotubes of silicon having n > 6 are stable but those with n < 6 can be stabilized by internal or external adsorption of transition metal elements. Some of these tubes have magnetic ground state leading to spintronic properties. We also examined the stability of nanotubes under radial and axial deformation. Owing to the weakness of radial restoring force, stable Si nanotubes are radially soft. Undeformed zigzag nanotubes are found to be metallic for 6 < n < 11 due to curvature effect; but a gap starts to open for n > 12. Furthermore, we identified stable tubular structures formed by stacking of Si polygons. We found AlP, GaAs, and GaN (8,0) single-wall nanotubes stable and semiconducting. Our results are compared with those of single-wall carbon nanotubes.Comment: 11 pages, 10 figure

Production of linalool, cis- and trans-nerolidol, and trans,trans-farnesol by Saccharomyces fermentati growing as a film on simulated wine

Linalool, cis-nerolidol, trans-nerolidol, and trans,trans-farnesol are produced in low concentrations by the wine yeast Saccharomyces fermentati growing as a film for 10 weeks on the surface of a simulated fino sherry containing ethanol as the only volatile carbon containing compound. lt is not known whether Saccharomyces cerevisiae also produces terpenes while fermenting grape juice to wine. However, caution seems advisable in differentiating among Vitis vinifera cultivars on the basis of terpenes found in the wines.Die Bildung von Linalool, cis- und trans-Nerolidol sowie trans,trans-Farnesol durch eine Decke von Saccharomyces fermentati auf einem ModellweinDie deckenbildende Form von Saccharomyces fermentati erzeugte im Verlauf von 10 Wochen auf einem simulierten Fino-Sherry, der als einzige flüchtige Kohlenstoffverbindung Äthanol enthielt, geringe Mengen von Linalool, cis-Nerolidol, trans-Nerolidol und trans,trans-Farnesol. Es ist zwar nicht bekannt, ob Saccharomyces cerevisiae bei der Vergärung von Traubensaft ebenfalls Terpene bildet; trotzdem scheint Vorsicht geboten zu sein, wenn Vitis-vinifera-Sorten aufgrund der in den Weinen gefundenen Terpene charakterisiert werden

Metacarpophalangeal pattern profile analysis in fragile X syndrome

We analyzed the metacarpophalangeal pattern profile (MCPP) on 18 male individuals from 16 families with fragile X—fra (X), or Martin-Bell—syndrome and calculated a mean syndrome profile. Fourteen of 18 individuals with fra (X) syndrome had significant positive correlations which indicated clinical homogeneity. Discriminant analysis of individuals with fra (X) syndrome compared with a sample of normal individuals produced a correct classification rate of 88% based on a function of 3 MCPP variables that may provide a useful tool in screening individuals for the fra (X) syndrome. Discriminant and correlation analyses of individuals with Sotos sequence and individuals with fra (X) syndrome did not identify MCPP similarities. Therefore, there was no MCPP evidence in our study of patients with Sotos sequence and fra (X) chromosome expression

Working time flexibility components and working time regimes in Europe: using company-level data across 21 countries

Working time ?exibility comprises a wide variety of arrangements, from part-time, overtime, to long-term leaves. Theoretical approaches to grouping these arrangements have been developed, but empirical underpinnings are rare. This article investigates the bundles that can be found for various ?exible working time arrangements, using the Establishment Survey on Working Time and Work–Life Balance, 2004/2005, covering 21 EU member states and 13 industries. The results from the factor analyses con?rmed that working time arrangements can be grouped into two bundles, one for the employee-centred arrangements and second for the employer-centred arrangements, and that these two bundles are separate dimensions.Wealso tested the stability of the factor analysisoutcome, showing that although we ?nd some deviations from the pan-Europe and pan-industry outcome, the naming of the components as ?exibility for employees and ?exibility for employers can be considered rather stable. Lastly, we ?nd three country clusters for the 21 European countries using the bundle approach. The ?rst group includes the Northern European countries along side Poland and Czech Republic, the second group the continental European countries with UK and Ireland, and lastly, the southern European countries with Hungary and Slovenia

Food chain approach to lowering the saturated fat of milk and dairy products

Lactating cow diets were supplemented with high oleic acid sunflower oil over two production periods spanning two years, to modify the milk fat, partially replacing saturated fatty acids (SFA) with cis-monounsaturated fatty acids (MUFA). The resulting milk was used for ultra-high temperature (UHT) milk, butter and Cheddar cheese production, and fatty acid profiles were compared with those of conventionally-produced products. Fat from products made with modified milk had lower SFA and higher cis- and trans-MUFA concentrations than that of conventional products. This was consistent over production periods, demonstrating that this food chain approach could be adopted on a wider scale

The design, construction and performance of the MICE scintillating fibre trackers

This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 ElsevierCharged-particle tracking in the international Muon Ionisation Cooling Experiment (MICE) will be performed using two solenoidal spectrometers, each instrumented with a tracking detector based on diameter scintillating fibres. The design and construction of the trackers is described along with the quality-assurance procedures, photon-detection system, readout electronics, reconstruction and simulation software and the data-acquisition system. Finally, the performance of the MICE tracker, determined using cosmic rays, is presented.This work was supported by the Science and Technology Facilities Council under grant numbers PP/E003214/1, PP/E000479/1, PP/E000509/1, PP/E000444/1, and through SLAs with STFC-supported laboratories. This work was also supportedby the Fermi National Accelerator Laboratory, which is operated by the Fermi Research Alliance, under contract No. DE-AC02-76CH03000 with the U.S. Department of Energy, and by the U.S. National Science Foundation under grants PHY-0301737,PHY-0521313, PHY-0758173 and PHY-0630052. The authors also acknowledge the support of the World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan

The University of Akron Human Powered Vehicle Team

The University of Akron Human Powered Vehicle Team’s 2016 vehicle, Klokan, was designed, manufactured and tested with safety, reliability, performance and ease of use in mind. The vehicle is a fully faired tadpole trike with a lightweight aluminum frame constructed from 6061-T6 tubing having a total weight of 8.9 lbs. To complement the lightweight frame, the fairing is constructed from polycarbonate, PETG and carbon fiber strips which combine into a lightweight, easy to manufacture weather barrier and aerodynamic structure. Klokan was designed to be a safe and efficient mode of everyday transportation which ensures that riders are sufficiently protected by a rollover protection system (RPS) which was designed to meet the ASME HPVC requirements with a minimum safety factor of two. The project scope includes all aspects of design and fabrication to create a vehicle that is easy to manufacture, easy to use, safe, and low cost to facilitate its usability in everyday situations. The team completed research on how to improve the manufacturability, reliability, and performance through analysis of designs, computer based modeling, and physical testing to validate that the bike meets team goals as well as exceeding the requirements set by the ASME Human Powered Vehicle Competition. The frame was designed in a manner that reduces welding through the use of bends and allows for precision fixturing to be manufactured and used to construct multiple frames quickly and efficiently. The fairing’s modular construction reduces the need for specialized tooling while minimizing weight and construction time. The team designed and successfully implemented an innovative rollover warning system which actively monitors the percentage of vehicle load on each tire and warns the driver through audible tone and visual warning light prior to a dangerous rollover becoming imminent

Population policies and education: exploring the contradictions of neo-liberal globalisation

The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives

No straight lines – young women’s perceptions of their mental health and wellbeing during and after pregnancy: a systematic review and meta-ethnography

Background: Young mothers face mental health challenges during and after pregnancy including increased rates of depression compared to older mothers. While the prevention of teenage pregnancy in countries such as the United States and the United Kingdom has been a focus for policy and research in recent decades, the need to understand young women’s own experiences has been highlighted. The aim of this meta-ethnography was to examine young women’s perceptions of their mental health and wellbeing during and after pregnancy to provide new understandings of those experiences. Methods: A systematic review and meta-ethnographic synthesis of qualitative research was conducted. Seven databases were systematically searched and forward and backward searching conducted. Papers were included if they were from Organisation for Economic Co-operation and Development countries and explored mental health and wellbeing experiences of young mothers (age under 20 in pregnancy; under 25 at time of research) as a primary research question – or where evidence about mental health and wellbeing from participants was foregrounded. Nineteen papers were identified and the Critical Appraisal Skills Programme checklist for qualitative research used to appraise the evidence. Following the seven-step process of meta-ethnography, key constructs were examined within each study and then translated into one another. Results: Seven translated themes were identified forming a new line of argument wherein mental health and wellbeing was analysed as relating to individual bodily experiences; tied into past and present relationships; underpinned by economic insecurity and entangled with feelings of societal surveillance. There were ‘no straight lines’ in young women’s experiences, which were more complex than dominant narratives around overcoming adversity suggest. Conclusions: The synthesis concludes that health and social care professionals need to reflect on the operation of power and stigma in young women’s lives and its impact on wellbeing. It adds to understanding of young women’s mental health and wellbeing during and after pregnancy as located in physical and structural factors rather than individual capacities alone