10,711 research outputs found

    New Zealand Guidelines for cyanobacteria in recreational fresh waters: Interim Guidelines

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    This document is divided into four main sections, plus 14 appendices. Section 1. Introduction provides an overview of the purpose and status of the document as well as advice on who should use it. Section 2. Framework provides a background to the overall guidelines approach, recommendations on agency roles and responsibilities, and information on the condition of use of this document. Section 3. Guidelines describes the recommended three-tier monitoring and action sequence for planktonic and benthic cyanobacteria. Section 4. Sampling provides advice on sampling planktonic and benthic cyanobacteria. The appendices give further background information and include templates for data collection and reporting, including: • background information on known cyanotoxins and their distribution in New Zealand • information on the derivation of guideline values • photographs of typical bloom events • a list of biovolumes for common New Zealand cyanobacteria • templates for field assessments • suggested media releases and warning sign templates. A glossary provides definitions for abbreviations and terms used in these guidelines

    Three Dimensional Mapping of Texture in Dental Enamel

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    We have used synchrotron x-ray diffraction to study the crystal orientation in human dental enamel as a function of position within intact tooth sections. Keeping tooth sections intact has allowed us to construct 2D and 3D spatial distribution maps of the magnitude and orientation of texture in dental enamel. We have found that the enamel crystallites are most highly aligned at the expected occlusal points for a maxillary first premolar, and that the texture direction varies spatially in a three dimensional curling arrangement. Our results provide a model for texture in enamel which can aid researchers in developing dental composite materials for fillings and crowns with optimal characteristics for longevity, and will guide clinicians to the best method for drilling into enamel, in order to minimize weakening of remaining tooth structure, during dental restoration procedure

    A linear-time algorithm for finding a complete graph minor in a dense graph

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    Let g(t) be the minimum number such that every graph G with average degree d(G) \geq g(t) contains a K_{t}-minor. Such a function is known to exist, as originally shown by Mader. Kostochka and Thomason independently proved that g(t) \in \Theta(t*sqrt{log t}). This article shows that for all fixed \epsilon > 0 and fixed sufficiently large t \geq t(\epsilon), if d(G) \geq (2+\epsilon)g(t) then we can find this K_{t}-minor in linear time. This improves a previous result by Reed and Wood who gave a linear-time algorithm when d(G) \geq 2^{t-2}.Comment: 6 pages, 0 figures; Clarification added in several places, no change to arguments or result

    A High-Density Linkage Map of the Ancestral Diploid Strawberry, Fragaria iinumae, Constructed with Single Nucleotide Polymorphism Markers from the IStraw90 Array and Genotyping by Sequencing

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    Fragaria iinumae Makino is recognized as an ancestor of the octoploid strawberry species, which includes the cultivated strawberry, Fragaria ×ananassa Duchesne ex Rozier. Here we report the construction of the first high-density linkage map for F. iinumae. The F. iinumae linkage map (Fii map) is based on two high-throughput techniques of single nucleotide polymorphism (SNP) genotyping: the IStraw90 Array (hereafter “Array”), and genotyping by sequencing (GBS). The F2 generation mapping population was derived by selfing F. iinumae hybrid F1D, the product of a cross between two divergent F. iinumae accessions collected from Hokkaido, Japan. The Fii map consists of seven linkage groups (LGs) and has an overall length of 451.7 cM as defined by 496 loci populated by 4173 markers: 3280 from the Array and 893 from GBS. Comparisons with two versions of the Fragaria vesca ssp. vesca L. ‘Hawaii 4’ pseudo-chromosome (PC) assemblies reveal substantial conservation of synteny and colinearity, yet identified differences that point to possible genomic divergences between F. iinumae and F. vesca, and/or to F. vesca genomic assembly errors. The Fii map provides a basis for anchoring a F. iinumae genome assembly as a prerequisite for constructing a second diploid reference genome for Fragaria

    Root branching affects the mobilisation of root-reinforcement in direct shear

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    The contribution of roots to the mechanical behaviour of soil has typically only been studied for the ultimate limit state. In these approaches, roots are typically modelled as straight and unbranched structures. This approach overlooks the fact that roots may have to deform significantly to mobilise their strength, a process that will be influenced by root architecture effects such as branching, amongst others. Sequential mobilisation of roots affects the peak root-reinforcement, thus differences in mobilisation are important to consider when quantifying root-reinforcement. In this paper, the effect of root branching was modelled using a large-deformation Euler-Bernoulli beam-spring model. The effect of soil was incorporated using non-linear springs, similar to p-y and t-z theory used for foundation piles. By connecting multiple beams together (i.e. applying appropriate linked boundary conditions at root connection points) the effect of branching could be analysed. A soil displacement profile corresponding with direct shear loading was then imposed and the response of the root analysed. It was shown that adding branches led to a quicker mobilisation of root-reinforcement. Branches increased the axial resistance to root displacement and changed the shape of the deformed roots. The presence of branching counteracted root slippage, and thus increased reinforcement. Larger branching densities increased this effect. This analysis demonstrated that the architecture of the root system has a strong effect on the mobilisation of root strength, which directly affects the maximum amount of reinforcement the roots will provide. Future modelling of root-reinforcement, both at the ultimate and serviceable limit state, should account for this effect

    ASPIRE-2-PREVENT: a survey of lifestyle, risk factor management and cardioprotective medication in patients with coronary heart disease and people at high risk of developing cardiovascular disease in the UK.

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    OBJECTIVE: To determine in patients with coronary heart disease (CHD) and people at high risk of developing cardiovascular disease (CVD) whether the Joint British Societies' guidelines on CVD prevention (JBS2) are followed in everyday clinical practice. DESIGN: A cross-sectional survey was undertaken of medical records and patient interviews and examinations at least 6 months after the recruiting event or diagnosis using standardised instruments and a central laboratory for measurement of lipids and glucose. SETTINGS: The ASPIRE-2-PREVENT survey was undertaken in 19 randomly selected hospitals and 19 randomly selected general practices in 12 geographical regions in England, Northern Ireland, Wales and Scotland. PATIENTS: In hospitals, 1474 consecutive patients with CHD were identified and 676 (25.6% women) were interviewed. In general practice, 943 people at high CVD risk were identified and 446 (46.5% women) were interviewed. RESULTS: The prevalence of risk factors in patients with CHD and high-risk individuals was, respectively: smoking 14.1%, 13.3%; obesity 38%, 50.2%; not reaching physical activity target 83.3%, 85.4%; blood pressure ≥130/80 mm Hg (patients with CHD and self-reported diabetes) or ≥140/85 mm Hg (high-risk individuals) 46.9%, 51.3%; total cholesterol ≥4 mmol/l 52.6%, 78.7%; and diabetes 17.8%, 43.8%. CONCLUSIONS: The potential among patients with CHD and individuals at high risk of developing CVD in the UK to achieve the JBS2 lifestyle and risk factor targets is considerable. CVD prevention needs a comprehensive multidisciplinary approach, addressing all aspects of lifestyle and risk factor management. The challenge is to engage and motivate cardiologists, physicians and other health professionals to routinely practice high quality preventive cardiology in a healthcare system which must invest in prevention

    Prioritizing Tasks in Code Repair: A Psychological Exploration of Computer Code

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    The current study explored the influence of task prioritization on how computer programmers reviewed and edited code. Forty-five programmers recruited from Amazon Mechanical Turk downloaded and edited a computer program in C#. Programmers were given instructions to review the code and told to prioritize either the reputation, transparency, or performance aspects of the code, or were given no prioritization instruction. Code changes and remarks about their changes to the code were analyzed with a between-within multivariate analysis of variance. Results indicate prioritizing an aspect of the code leads to increased performance on that aspect, but with deficits to other aspects of the code. Managers may want programmers to prioritize certain aspects of code depending on the stage of development of the software (i.e., testing, rollout, etc.). However, managers should also be cognizant of the effects task prioritization has on programmer perceptions of the code as a whole

    The variance on the shock response of a carbon fibre composite due to the orientation of the weave

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    Three different orientations of a tape-wrapped carbon fibre composite with phenolic resin matrix (abbreviated to TWCP) have been investigated under one-dimensional shock loading. This has been achieved via a single-stage gas gun, with manganin gauges as the diagnostic tool. The orientations of TWCP studied in this paper were 25°, 45° and 90°, with respect to the impact face. The shock response of these orientations, for this material, has been obtained (the Hugoniot equation of state). These results have been contrasted with previously reported literature data for the same material at different orientations (0° and 20°). It was found that orientation had minimal effect on the behaviour of this composite under shock. The exception to this was the 90° orientation which exhibited an elastic precursor at particle velocities of less than 0.65 mm µs−1; where the shock velocity was equivalent to the elastic sound speed of the material

    The bactericidal effect of shock waves

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    There are a variety of theories relating to the origins of life on our home planet, some of which discuss the possibility that life may have been spread via inter-planetary bodies. There have been a number of investigations into the ability of life to withstand the likely conditions generated by asteroid impact (both contained in the impactor and buried beneath the planet surface). Previously published data regarding the ability of bacteria to survive such applied shockwaves has produced conflicting conclusions. The work presented here used an established and published technique in combination with a single stage gas gun, to shock and subsequently recover Escherichia coli populations suspended in a phosphate buffered saline solution. Peak pressure across the sample region was calculated via numerical modelling. Survival data against peak sample pressure for recovered samples is presented alongside control tests. SEM micrographs of shocked samples are presented alongside control sets to highlight key differences between cells in each case
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