3,892 research outputs found

    Noise Robust Blind System Identification Algorithms Based On A Rayleigh Quotient Cost Function

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    Trade unions and democracy in South Africa: union organisational challenges and solidarities in a time of transformation

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    Based on a nationwide survey, this article focuses on the perceptions of Congress of South African Trade Unions (COSATU) members on two of the central issues that have dominated debates on the South African labour movement: the advisability of COSATU's Alliance with the African National Congress (ANC) and the extent of internal union democracy. The survey revealed that the ANC-Alliance continues to enjoy mass support, while internal democracy remains robust. At the same time, the federation faces the challenges of coping with — and contesting — neoliberal reforms, retaining and re-energizing rank and file in the post-apartheid era, and in reaching out to potential members in the informal sector and other areas of insecure work

    A Combined EIS-NVSS Survey Of Radio Sources (CENSORS) III: Spectroscopic observations

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    The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) is a 1.4GHz radio survey selected from the NRAO VLA Sky Survey (NVSS) and complete to a flux-density of 7.2mJy. It targets the ESO Imaging Survey (EIS) Patch D, which is a 3 by 2 square degree field centred on 09 51 36.0, -21 00 00 (J2000). This paper presents the results of spectroscopic observations of 143 of the 150 CENSORS sources. The primary motivation for these observations is to achieve sufficient spectroscopic completeness so that the sample may be used to investigate the evolution of radio sources. The observations result in secure spectroscopic redshifts for 63% of the sample and likely redshifts (based on a single emission line, for example) for a further 8%. Following the identification of the quasars and star-forming galaxies in the CENSORS sample, estimated redshifts are calculated for the remainder of the sample via the K-z relation for radio galaxies. Comparison of the redshift distribution of the CENSORS radio sources to distributions predicted by the various radio luminosity function evolution models of Dunlop & Peacock 1990, results in no good match. This demonstrates that this sample can be used to expand upon previous work in that field.Comment: Accepted for publication in MNRAS. This version has some reduced resolution figures and 13 associated gif files. A version with all figures incorporated (at full resolution) is available at http://www.roe.ac.uk/~pnb/papers/censors_spectro.pd

    Temperature changes and the ATP concentration of the soil microbial biomass

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    Two soils from temperate sites (UK; arable and grassland) were incubated aerobically at 0, 5, 15 or 258C for up to 23 days. During this period both soils were analysed for soil microbial biomass carbon (biomass C) and adenosine 5' triphosphate contents (ATP). Biomass C did not change signi\uaecantly in either soil at any temperature throughout, except during days 0 to 1 in the grassland soil. Soil ATP contents increased slowly throughout the 23 days of incubation, from 2.2 to a maximum of 3.1 nmol ATP g \uff1 soil in the arable soil (a 40% increase) and from 6.2 to a maximum of 11.2 nmol ATP g \uff1 soil in the grassland soil (an increase of 81%), both at 258C. Since biomass C did not change either with increasing temperature or increasing time of incubation, it was concluded that an increase in ATP was either due to an increase in adenylate energy charge or de novo synthesis of ATP, or both. During the incubation, biomass ATP concentrations ranged from about 5 to 12 mmol ATP g \uff1 biomass C but trends between biomass ATP and incubation temperatures were not very obvious until about day 13. On day 23, biomass ATP concentrations were positively and linearly related to temperature: (mmol ATP g \uff1 biomass C = 6.9820.35 + 0.13420.023 T0 (r 2 = 0.77) with no signi\uaecant di erence in the slope between the grassland and arable soils. At 258C the biomass ATP concentration was 10.3 mmol g \uff1 biomass C, remarkably close to many other published values. It was concluded that, although the biomass increased its ATP concentration in response to increasing temperature, the increase was comparatively small. Also, at all temperatures tested, the biomass maintained its ATP concentration within the range commonly reported for micro-organisms growing expontentially in vitro. This is despite the fact that the biomass normally exhibits other features more typical of a ``resting'' or dormant population 0 a paradox which still is not resolved

    Hole-depletion of ladders in Sr14_{14}Cu24_{24}O41_{41} induced by correlation effects

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    The hole distribution in Sr14_{14}Cu24_{24}O41_{41} is studied by low temperature polarization dependent O K Near-Edge X-ray Absorption Fine Structure measurements and state of the art electronic structure calculations that include core-hole and correlation effects in a mean-field approach. Contrary to all previous analysis, based on semi-empirical models, we show that correlations and antiferromagnetic ordering favor the strong chain hole-attraction. For the remaining small number of holes accommodated on ladders, leg-sites are preferred to rung-sites. The small hole affinity of rung-sites explains naturally the 1D - 2D cross-over in the phase diagram of (La,Y,Sr,Ca)14_{14}Cu24_{24}O41_{41}Comment: 6 pages, 8 figure

    Orbital occupancies and the putative jeff = 1/2 groundstate in Ba2IrO4: a combined oxygen K edge XAS and RIXS study

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    The nature of the electronic groundstate of Ba2IrO4 has been addressed using soft X-ray absorption and inelastic scattering techniques in the vicinity of the oxygen K edge. From the polarization and angular dependence of XAS we deduce an approximately equal superposition of xy, yz and zx Ir4+ 5d orbitals. By combining the measured orbital occupancies, with the value of the spin-orbit coupling provided by RIXS, we estimate the crystal field splitting associated with the tetragonal distortion of the IrO6 octahedra to be small, \Delta=50(50) meV. We thus conclude definitively that Ba2IrO4 is a close realization of a spin-orbit Mott insulator with a jeff = 1/2 groundstate, thereby overcoming ambiguities in this assignment associated with the interpretation of X-ray resonant scattering experiments.Comment: 5 pages, 5 figure

    Responses to supplementation by dairy cows given low pasture allowances in different seasons 2. Milk production

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    Two factorial experiments were designed to determine the effects of stage of lactation, and season of the year, on cow responses to supplementary feeding. These experiments were conducted over consecutive years with 128 high genetic merit multiparous Holstein-Friesian cows in early, mid and late lactation in spring, summer, autumn and winter. At each stage of lactation, and in each season of the year, cows were offered a restricted pasture allowance (25 to 35 kg dry matter (DM) per cow per day), either unsupplemented (control) or with supplement at 50 MJ metabolizable energy (ME) per cow per day in experiment 1 and 80 MJ ME per cow per day in experiment 2. The two supplements given in both years were rolled maize grain (MG) and a mixture of foods formulated to nutritionally balance the diet (BR). In experiment 2, another treatment, of a generous pasture allowance (60 to 75 kg DM per cow per day) (AP), was imposed on an additional group of early lactation cows during each season. Direct milk solids (MS) (milk fat plus milk protein) responses in experiment 1 to MG were 169, 279, 195 and 251 g MS per cow per day in spring, summer, autumn and winter, respectively, while those to BR were 107, 250, 192, 289 g MS per cow per day. In experiment 2, however, milk solids responses to both supplements during spring were slightly below the control treatment, with values similar to those in experiment 1 in summer and autumn for cows on the BR but not the MG supplement. Milk solids responses to supplementary foods were largest during seasons of the year when the quantity and quality of pasture on offer resulted in the lowest milk solids yield from unsupplemented cows. When carry-over effects of feeding MG and BR on milk solids production were detected, they were only about half the magnitude of the direct effects. Serum urea concentrations were higher in control cows than those offered MG with a similar effect for BR in all but summer in experiment 1, while serum glucose concentrations were highest in winter and lowest in summer. The most important factor influencing milk solids responses was the relative food deficit (RFD) represented by the decline in milk solids yield of the respective control groups after,changing from a generous pasture allowance to restricted allowance when the feeding treatments were imposed. Total milk solids responses (direct and carry-over) to supplements were greatest when severe food restrictions, relative to the cows' current food demand, resulted in large reductions in milk solids yield of the control groups. The RFD was the best predictor of milk solids response to supplementary foods. Therefore, it is likely that cows are most responsive to supplementary foods during or immediately after the imposition of a severe food restriction

    Impact of the National Institute for Health and Care Excellence (NICE) guidance on medical technology uptake: analysis of the uptake of spinal cord stimulation in England 2008-2012.

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    This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: The National Institute for Health and Care Excellence (NICE) Technology Appraisal Guidance on spinal cord stimulation (SCS) was published in 2008 and updated in 2012 with no change. This guidance recommends SCS as a cost-effective treatment for patients with neuropathic pain. OBJECTIVE: To assess the impact of NICE guidance by comparing SCS uptake in England pre-NICE (2008-2009) and post-NICE (2009-2012) guidance. We also compared the English SCS uptake rate with that of Belgium, the Netherlands, France and Germany. DESIGN: SCS implant data for England was obtained from the Hospital Episode Statistics (HES) database and compared with other European countries where comparable data were available. RESULTS: The HES data showed small increases in SCS implantation and replacement/revision procedures, and a large increase in SCS trials between 2008 and 2012. The increase in the total number of SCS procedures per million of population in England is driven primarily by revision/replacements and increased trial activity. Marked variability in SCS uptake at both health regions and primary care trust level was observed. CONCLUSIONS: Despite the positive NICE recommendation for the routine use of SCS, we found no evidence of a significant impact on SCS uptake in England. Rates of SCS implantation in England are lower than many other European countries.Access to the QUANTIS database to extract the relevant Hospital Episode Statistics data was funded by Medtronic UK

    Origin of interface magnetism in BiMnO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures

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    Possible ferromagnetism induced in otherwise non-magnetic materials has been motivating intense research in complex oxide heterostructures. Here we show that a confined magnetism is realized at the interface between SrTiO3 and two insulating polar oxides, BiMnO3 and LaAlO3. By using polarization dependent x-ray absorption spectroscopy, we find that in both cases the magnetic order is stabilized by a negative exchange interaction between the electrons transferred to the interface and local magnetic moments. These local magnetic moments are associated to Ti3+ ions at the interface itself for LaAlO3/SrTiO3 and to Mn3+ ions in the overlayer for BiMnO3/SrTiO3. In LaAlO3/SrTiO3 the induced magnetic moments are quenched by annealing in oxygen, suggesting a decisive role of oxygen vacancies in the stabilization of interfacial magnetism.Comment: 5 pages, 4 figure

    Responses to supplementation by dairy cows given low pasture allowances in different seasons 1. Pasture intake and substitution

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    Two factorial experiments were designed to determine the effects of stage of lactation, and season of the year, on cow responses to supplementary feeding. These experiments were conducted over consecutive years with 128 high genetic merit multiparous Holstein-Friesian cows in early, mid and late lactation in spring, summer, autumn and winter. At each stage of lactation, and in each season of the year, cows were offered a restricted pasture allowance (25 to 35 kg dry matter (DM) per cow per day), either unsupplemented (control) or supplemented with 50 MJ metabolizable energy (ME) per cow per day in experiment 1 and 80 MJ ME per cow per day in experiment 2. Two different supplements were offered, namely, rolled maize grain (MG) and a mixture of foods (BR) formulated to nutritionally balance the diet. In experiment 2, a fourth treatment consisting solely of a generous pasture allowance (60 to 75 kg DM per cow per day, AP) was introduced. Offering MG and BR increased DM intake (DMI). At the restricted pasture allowance, increasing total ME allowance (MEA) by offering supplementary foods increased ME intake (MEI) by 0.68 (s.e. 0.047) MJ per extra MJ ME offered. This highly significant (P < 0.001) linear relationship was consistent across seasons, and did not diminish at higher MEA. In experiment 2, cows in early lactation had lower substitution rates than mid and late lactation cows irrespective of season. Substitution rate was higher when higher pasture allowance or quality of pasture on offer enabled the unsupplemented cows to achieve higher DMI from pasture than at other times of the year. These results suggest that one of the key factors determining the intake response to supplementary foods is pasture allowance. Within spring calving dairying systems, the largest increases in total DMI per kg of supplement offered is likely when offering supplements to early lactation cows grazing restricted allowances of high quality pasture
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