Magnetically suspended flywheel system study

A program to study the application of a graphite/epoxy, magnetically suspended, pierced disk flywheel for the combined function of spacecraft attitude control and energy storage (ACES) is described. Past achievements of the program include design and analysis computer codes for the flywheel rotor, a magnetically suspended flywheel model, and graphite/epoxy rotor rings that were successfully prestressed via interference assembly. All hardware successfully demonstrated operation of the necessary subsystems which form a complete ACES design. Areas of future work include additional rotor design research, system definition and control strategies, prototype development, and design/construction of a UM/GSFC spin test facility. The results of applying design and analysis computer codes to a magnetically suspended interference assembled rotor show specific energy densities of 42 Wh/lb (92.4 Wh/kg) are obtained for a 1.6 kWh system

A simple reactive-transport model of calcite precipitation in soils and other porous media

Calcite formation in soils and other porous media generally occurs around a localised source of reactants, such as a plant root or soil macro-pore, and the rate depends on the transport of reactants to and from the precipitation zone as well as the kinetics of the precipitation reaction itself. However most studies are made in well mixed systems, in which such transport limitations are largely removed. We developed a mathematical model of calcite precipitation near a source of base in soil, allowing for transport limitations and precipitation kinetics. We tested the model against experimentally-determined rates of calcite precipitation and reactant concentration–distance profiles in columns of soil in contact with a layer of HCO3−-saturated exchange resin. The model parameter values were determined independently. The agreement between observed and predicted results was satisfactory given experimental limitations, indicating that the model correctly describes the important processes. A sensitivity analysis showed that all model parameters are important, indicating a simpler treatment would be inadequate. The sensitivity analysis showed that the amount of calcite precipitated and the spread of the precipitation zone were sensitive to parameters controlling rates of reactant transport (soil moisture content, salt content, pH, pH buffer power and CO2 pressure), as well as to the precipitation rate constant. We illustrate practical applications of the model with two examples: pH changes and CaCO3 precipitation in the soil around a plant root, and around a soil macro-pore containing a source of base such as urea

Foodborne disease outbreaks in Australia 2001-2009

BACKGROUND: Analysis of surveillance data from foodborne disease outbreaks can help identify high-risk aetiological agents, food vehicles and settings. This information may help prevent future illness by informing the development of public health policy

A randomised trial of an internet weight control resource: The UK Weight Control Trial [ISRCTN58621669]

BACKGROUND: Obesity treatment is notoriously unsuccessful and one of the barriers to successful weight loss reported by patients is a lack of social support. The Internet offers a novel and fast approach to the delivery of health information, enabling 24-hour access to help and advice. However, much of the health information available on the Internet is unregulated or not written by qualified health professionals to provide unbiased information. The proposed study aims to compare a web-based weight loss package with traditional dietary treatment of obesity in participants. The project aims to deliver high quality information to the patient and to evaluate the effectiveness of this information, both in terms of weight loss outcomes and cost-effectiveness. METHODS: This study is a randomised controlled trial of a weight loss package against usual care provided within General Practice (GP) surgeries in Leeds, UK. Participants will be recruited via posters placed in participating practices. A target recruitment figure of 220 will enable 180 people to be recruited (allowing for 22% dropout). Participants agreeing to take part in the study will be randomly allocated using minimisation to either the intervention group, receiving access to the Internet site, or the usual care group. The primary outcome of the study will be the ability of the package to promote change in BMI over 6 and 12 months compared with traditional treatment. Secondary outcomes will be the ability of the Internet package to promote change in reported lifestyle behaviours. Data will be collected on participant preferences, adherence to treatment, health care use and time off work. Difference in cost between groups in provision of the intervention and the cost of the primary outcome will also be estimated. CONCLUSION: A positive result from this study would enhance the repertoire of treatment approaches available for the management of obesity. A negative result would be used to inform the research agenda and contribute to redefining future strategies for tackling obesity

A Different Approach to Horse Handling, Based on the Jeffery Method

A method of horse training is discussed, which is based on an old technique known in Australia as the Jeffery method. It uses several behavioral principles, including understanding horse behavior, reinforcement for desired behavior, and flight distance principles

A Different Approach to Horse Handling, Based on the Jeffery Method

A method of horse training is discussed which is based on an old technique known in Australia as the Jeffery method. It makes use of several behavioral principles, including understanding of horse behavior, reinforcement for desired behavior, and use of flight distance principles

Direct observation of size scaling and elastic interaction between nano-scale defects in collision cascades

Using in-situ transmission electron microscopy, we have directly observed nano-scale defects formed in ultra-high purity tungsten by low-dose high energy self-ion irradiation at 30K. At cryogenic temperature lattice defects have reduced mobility, so these microscope observations offer a window on the initial, primary damage caused by individual collision cascade events. Electron microscope images provide direct evidence for a power-law size distribution of nano-scale defects formed in high-energy cascades, with an upper size limit independent of the incident ion energy, as predicted by Sand et al. [Eur. Phys. Lett., 103:46003, (2013)]. Furthermore, the analysis of pair distribution functions of defects observed in the micrographs shows significant intra-cascade spatial correlations consistent with strong elastic interaction between the defects

Current Star Formation in the Ophiuchus and Perseus Molecular Clouds: Constraints and Comparisons from Unbiased Submillimeter and Mid-Infrared Surveys. II

We present a census of the population of deeply embedded young stellar objects (YSOs) in the Ophiuchus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the "Cores to Disks" (c2d) legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. We have applied a method developed for identifying embedded protostars in Perseus to these datasets and in this way construct a relatively unbiased sample of 27 candidate embedded protostars with envelopes more massive than our sensitivity limit (about 0.1 M_sun). Embedded YSOs are found in 35% of the SCUBA cores - less than in Perseus (58%). On the other hand the mid-infrared sources in Ophiuchus have less red mid-infrared colors, possibly indicating that they are less embedded. We apply a nearest neighbor surface density algorithm to define the substructure in each of the clouds and calculate characteristic numbers for each subregion - including masses, star formation efficiencies, fraction of embedded sources etc. Generally the main clusters in Ophiuchus and Perseus (L1688, NGC1333 and IC348) are found to have higher star formation efficiencies than small groups such as B1, L1455 and L1448, which on the other hand are completely dominated by deeply embedded protostars. We discuss possible explanations for the differences between the regions in Perseus and Ophiuchus, such as different evolutionary timescales for the YSOs or differences, e.g., in the accretion in the two clouds.Comment: Accepted for publication in ApJ (56 pages, 13 figures; abstract abridged). Version with full-resolution figures available at http://www.astro.uni-bonn.de/~jes/paper120.pd

Connected component identification and cluster update on GPU

Cluster identification tasks occur in a multitude of contexts in physics and engineering such as, for instance, cluster algorithms for simulating spin models, percolation simulations, segmentation problems in image processing, or network analysis. While it has been shown that graphics processing units (GPUs) can result in speedups of two to three orders of magnitude as compared to serial codes on CPUs for the case of local and thus naturally parallelized problems such as single-spin flip update simulations of spin models, the situation is considerably more complicated for the non-local problem of cluster or connected component identification. I discuss the suitability of different approaches of parallelization of cluster labeling and cluster update algorithms for calculations on GPU and compare to the performance of serial implementations.Comment: 15 pages, 14 figures, one table, submitted to PR

Rice genotype differences in tolerance of zinc-deficient soils: evidence for the importance of root-induced changes in the rhizosphere

The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fpls.2015.01160Zinc (Zn) deficiency is a major constraint to rice production and Zn is also often deficient in humans with rice-based diets. Efforts to breed more Zn-efficient rice are constrained by poor understanding of the mechanisms of tolerance to deficiency. Here we assess the contributions of root growth and root Zn uptake efficiency, and we seek to explain the results in terms of specific mechanisms. We made a field experiment in a highly Zn-deficient rice soil in the Philippines with deficiency-tolerant and -sensitive genotypes, and measured growth, Zn uptake and root development. We also measured the effect of planting density. Tolerant genotypes produced more crown roots per plant and had greater uptake rates per unit root surface area; the latter was at least as important as root number to overall tolerance. Tolerant and sensitive genotypes took up more Zn per plant at greater planting densities. The greater uptake per unit root surface area, and the planting density effect can only be explained by root-induced changes in the rhizosphere, either solubilizing Zn, or neutralizing a toxin that impedes Zn uptake (possibly HCO − 3 HCO3− or Fe2+), or both. Traits for these and crown root number are potential breeding targets.This research was funded by a grant from the UK's Biotechnology and Biological Sciences Research Council (BBSRC, Grant Ref. BB/J011584/1) under the Sustainable Crop Production Research for International Development (SCPRID) programme, a joint multi-national initiative of BBSRC, the UK Government's Department for International Development (DFID) and (through a grant awarded to BBSRC) the Bill & Melinda Gates Foundation. Support to AKN in the form of a fellowship awarded by the Japan Society for the Promotion of Science (JSPS) is gratefully acknowledged