3,056 research outputs found

    Productivity and income of New Zealand agriculture 1921-67

    Get PDF
    Supplement to Research report (Lincoln College (University of Canterbury). Agricultural Economics Research Unit) ; no. 59. Data revised back to 1962/63 in same series / by S.M. Hadfield.This discussion paper updates the data on income and productivity for the New Zealand agricultural sector for the period 1921-1967 in the AERU research report titled: Productivity and income of New Zealand agriculture, 1921-67

    Destruction of chain-superconductivity in YBa_2Cu_4O_8 in a weak magnetic field

    Full text link
    We report measurements of the temperature dependent components of the magnetic penetration depth {\lambda}(T) in single crystal samples of YBa_2Cu_4O_8 using a radio frequency tunnel diode oscillator technique. We observe a downturn in {\lambda}(T) at low temperatures for currents flowing along the b and c axes but not along the a axis. The downturn in {\lambda}_b is suppressed by a small dc field of ~0.25 T. This and the zero field anisotropy of {\lambda}(T) likely result from proximity induced superconducting on the CuO chains, however we also discuss the possibility that a significant part of the anisotropy might originate from the CuO2 planes.Comment: 5 page

    Evaluation of children's centres in England (ECCE) : strand 1: first survey of children's centre leaders in the most deprived areas

    Get PDF
    This report is the first output from the Evaluation of Children's Centres in England (ECCE), a six year study commissioned by the Department for Education and undertaken by NatCen Social Research, the University of Oxford and Frontier Economics. The aim of ECCE is to provide an in-depth understanding of children's centre services, including their effectiveness in relation to different management and delivery approaches and the cost of delivering different types of services. The aim of Strand 1 is to profile children’s centres in the most disadvantaged areas, providing estimates on different aspects of provision with which to select centres for subsequent stages of the evaluation and to explore different models of provision. The findings below relate to 500 children's centres that are representative of all phase 1 and 2 centres (i.e. those in the 30percent most deprived areas).</p

    Shubnikov-de Haas oscillations in YBa_2Cu_4O_8

    Full text link
    We report the observation of Shubnikov-de Haas oscillations in the underdoped cuprate superconductor YBa2_2Cu4_4O8_8 (Y124). For field aligned along the c-axis, the frequency of the oscillations is 660±30660\pm 30 T, which corresponds to 2.4\sim 2.4 % of the total area of the first Brillouin zone. The effective mass of the quasiparticles on this orbit is measured to be 2.7±0.32.7\pm0.3 times the free electron mass. Both the frequency and mass are comparable to those recently observed for ortho-II YBa2_2Cu3_3O6.5_{6.5} (Y123-II). We show that although small Fermi surface pockets may be expected from band structure calculations in Y123-II, no such pockets are predicted for Y124. Our results therefore imply that these small pockets are a generic feature of the copper oxide plane in underdoped cuprates.Comment: v2: Version of paper accepted for publication in Physical Review Letters. Only minor changes to the text and reference

    a systematic review protocol

    Get PDF
    Introduction Varicella zoster virus (VZV) causes varicella (chicken pox) and herpes zoster (shingles). Worldwide, these diseases are associated with significant morbidity. Most of the epidemiological data on VZV come from high income countries. There are few data on VZV in Africa, where tropical climates and high HIV/AIDS prevalence rates are expected to impact the epidemiology of VZV. Safe and effective vaccinations for both varicella and herpes zoster exist, but are not routinely used in Africa. There are very few data available on VZV disease burden in Africa to guide the introduction of these vaccines on the continent. Our aim is to conduct a systematic review of the VZV-associated morbidity and mortality in Africa, which will provide critical information that could be used to develop vaccination policies against these diseases in Africa. Methods and analysis Electronic databases will be searched and all studies published after 1974 that meet predefined criteria will be assessed. The primary outcomes for the study are VZV incidence/prevalence, hospitalisation rates and total death rates. The secondary outcome for this study is the proportion of VZV hospitalisations and/or deaths associated with HIV/AIDS. Two reviewers will screen the titles and abstracts, and then independently review the full texts, to determine if studies are eligible for inclusion. A risk of bias and quality assessment tool will be used to score all included studies. Following standardised data extraction, a trend analysis using R-programming software will be conducted to investigate the trend of VZV. Depending on the characteristics of included studies, subgroup analyses will be performed. This review will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Ethics and dissemination As this is a protocol for a systematic review, which will use already published data, no ethics approval is required. Findings will be disseminated in peer-reviewed journals. Trial registration number CRD4201502614

    Iron oxidation at low temperature (260–500 C) in air and the effect of water vapor

    Get PDF
    The oxidation of iron has been studied at low temperatures (between 260 and 500 C) in dry air or air with 2 vol% H2O, in the framework of research on dry corrosion of nuclear waste containers during long-term interim storage. Pure iron is regarded as a model material for low-alloyed steel. Oxidation tests were performed in a thermobalance (up to 250 h) or in a laboratory furnace (up to 1000 h). The oxide scales formed were characterized using SEM-EDX, TEM, XRD, SIMS and EBSD techniques. The parabolic rate constants deduced from microbalance experiments were found to be in good agreement with the few existing values of the literature. The presence of water vapor in air was found to strongly influence the transitory stages of the kinetics. The entire structure of the oxide scale was composed of an internal duplex magnetite scale made of columnar grains and an external hematite scale made of equiaxed grains. 18O tracer experiments performed at 400 C allowed to propose a growth mechanism of the scale

    The 3D printing of a polymeric electrochemical cell body and its characterisation

    No full text
    An undivided flow cell was designed and constructed using additive manufacturing technology and its mass transport characteristics were evaluated using the reduction of ferricyanide, hexacyanoferrate (III) ions at a nickel surface. The dimensionless mass transfer correlation Sh = aRebScdLee was obtained using the convective-diffusion limiting current observed in linear sweep voltammetry; this correlation compared closely with that reported in the literature from traditionally machined plane parallel rectangular flow channel reactors. The ability of 3D printer technology, aided by computational graphics, to rapidly and conveniently design, manufacture and re-design the geometrical characteristics of the flow cell ishighlighted
    corecore