1,843 research outputs found

    Domestic and International Pressures for European Agricultural Adjustment and Their Implications

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    General economic forces acting upon structural change in agriculture dominate the impacts of changes in agricultural policy. Particular factors are: (1) High demand for land for nonagricultural purposes. (2) High demand for residences in rural areas. (3) Demand for leisure space. (4) Changing occupational expectations and a move away from physical labour. Structural adjustment in agriculture is a steady process, driven by the enlargement of commercial farms and by the marginalisation of large numbers of smaller farms whose managers increasingly rely on off farm income and part-time operation. The most heavily commercial sector is becoming less dependent upon traditional support and more heavily influenced by the integrated contracts with downstream processors. The rate and direction of farm structure adjustment in the EU is unlikely to change as a consequence of any likely reforms in agricultural policy. The separation of EU farming into commercial and lifestyle/part-time operations lends itself to a two-track policy, with conservation and amenity output policy concentrated on the latter.Agricultural and Food Policy,

    Gaining from Improved Dairy Cow Nutrition: Economic, environmental and animal health benefits

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    A majority of UK dairy herds have the potential to increase profitability by improving the ration of their cows. This paper reports that gains averaging around £100 per cow have been made within one year of adopting the Keenan Hi-Fibre ration by 239 UK herds in 2006 and 2007. Larger gains have been made by herds in France. The key performance indicator underlying these gains is Feed Conversion Efficiency, whereby the same, or even a smaller amount of Dry Matter Intake generates higher yields per cow. Importantly, the gains are associated with large improvements in animal health and reductions in greenhouse gases per litre of milk produced.Feed conversion efficiency, cattle nutrition, greenhouse gas emissions, animal health., Livestock Production/Industries,

    Causes of irregularities in trends of global mean surface temperature since the late 19th century

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    The time series of monthly global mean surface temperature (GST) since 1891 is successfully reconstructed from known natural and anthropogenic forcing factors, including internal climate variability, using a multiple regression technique. Comparisons are made with the performance of 40 CMIP5 models in predicting GST. The relative contributions of the various forcing factors to GST changes vary in time, but most of the warming since 1891 is found to be attributable to the net influence of increasing greenhouse gases and anthropogenic aerosols. Separate statistically independent analyses are also carried out for three periods of GST slowdown (1896–1910, 1941–1975, and 1998–2013 and subperiods); two periods of strong warming (1911–1940 and 1976–1997) are also analyzed. A reduction in total incident solar radiation forcing played a significant cooling role over 2001–2010. The only serious disagreements between the reconstructions and observations occur during the Second World War, especially in the period 1944–1945, when observed near-worldwide sea surface temperatures (SSTs) may be significantly warm-biased. In contrast, reconstructions of near-worldwide SSTs were rather warmer than those observed between about 1907 and 1910. However, the generally high reconstruction accuracy shows that known external and internal forcing factors explain all the main variations in GST between 1891 and 2015, allowing for our current understanding of their uncertainties. Accordingly, no important additional factors are needed to explain the two main warming and three main slowdown periods during this epoch

    Challenges relating to comparison of flavonoid glycosides dissolution profiles from Sutherlandia frutescens products

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    Unlike the case of conventional drug formulations, dissolution tests have hitherto not been required for herbal medicinal products commercially available in South Africa. This study investigated dissolution of the South African Sutherlandia frutescens using selected flavonoid glycosides as marker compounds. Dissolution of markers was assessed in three dissolution media at pH 1.2, 4.5 and 6.8, and samples were analysed using a validated HPLC method. The dissolution profile of each marker varied for the different materials investigated. All three media utilised showed differences in flavonoid glycoside dissolution between the S. frutescens products evaluated, with f2 values <50 for comparison of flavonoid dissolution from any two of the materials. Dissolution of S. frutescens materials could thus be characterised using the markers in all the media tested. This tool may be employed in the future for comparison of orally administered S. frutescens products, provided between batch variability is evaluated and found less than between-sample variability.IS

    Solution-processable silicon phthalocyanines in electroluminescent and photovoltaic devices

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    E.Z.-C. acknowledges the University of St. Andrews for financial support. The authors thank the EPSRC UK National Mass Spectrometry Facility at Swansea University for analytical services. I.D.W.S. acknowledges support from the EPSRC (grant EP/J01771X), the European Research Council (grant 321305), and a Royal Society Wolfson Research Merit Award.Phthalocyanines and their main group and metal complexes are important classes of organic semiconductor materials, but are usually highly insoluble so frequently need to be processed by vacuum deposition in devices. We report two highly soluble silicon phthalocyanine (SiPc) diester compounds and demonstrate their potential as organic semiconductor materials. Near-infrared (λEL = 698-709 nm) solution-processed organic light- emitting diodes (OLEDs) were fabricated and exhibited external quantum efficiencies (EQEs) of up to 1.4%. Binary bulk heterojunction solar cells employing P3HT or PTB7 as the donor and the SiPc as the acceptor provided power conversion efficiencies (PCE) of up to 2.7% under simulated solar illumination. Our results show that soluble SiPcs are promising materials for organic electronics.Publisher PDFPeer reviewe

    Chiral iridium(III) complexes in light-emitting electrochemical cells : exploring the impact of stereochemistry on the photophysical properties and device performances

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    Despite hundreds of cationic bis-cyclometalated iridium(III) complexes having been explored as emitters for light-emitting electrochemical cells (LEECs), uniformly their composition has been in the form of a racemic mixture of Λ and Δ enantiomers. The investigation of LEECs using enantiopure iridium(III) emitters, however, remains unprecedented. Herein, we report the preparation, the crystal structures and the optoelectronic properties of two families of cyclometalated iridium(III) complexes of the form of [(C^N)2Ir(dtBubpy)]PF6 (where dtBubpy is 4,4'-di-tert-butyl-2,2'-bipyridine) in both their racemic and enantiopure configurations. LEEC devices using Λ and Δ enantiomers as well as the racemic mixture of both families have been prepared and the device performances were tested. Importantly, different solid-state photophysical properties exist between enantiopure and racemic emitters, which are also reflected in the device performances.Publisher PDFPeer reviewe

    Analysis of United Kingdom Off-Highway Construction Machinery Market and Its Consumers Using New-Sales Data

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    The off-highway construction machinery market and its consumers have attracted minimal previous research. This study addresses that void by analyzing annual United Kingdom (UK) (volume/portfolio) new-sales data for the 10 most popular products within that market, 1990–2010 inclusive. Graphical, descriptive statistical, Pearson-correlational, autocorrelational, and elementary modeling are employed to identify contrasts in sales regarding (1) high- and low-volume items; (2) growth trends and significant recessionary effects on volumes; (3) a demand change point circa 1997, since when annual product portfolio has changed little; and (4) product associations in consumer demand. Significant association is demonstrated between demand and construction output, especially with the value of new housing. Subsequently, consumption of wheeled loaders is modeled using construction volume, and demand for mini and crawler excavators is modeled using new-housing data. Time series trends for these machinery types are presented and forecast through 2015. The primary contribution of this study is a deeper understanding of the UK new-machinery market and the predilections of its consumers over the last two decades (to present)

    Synthesis, properties and Light-Emitting Electrochemical Cell (LEEC) device fabrication of cationic Ir(III) complexes bearing electron-withdrawing groups on the cyclometallating ligands

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    The authors are grateful to the European Research Council (grant 321305), the EPSRC (EP/M02105X/1) and the University of St Andrews for financial support. C.M. thanks Ministry of Economy and Competitiveness (MINECO, Spain) for her predoctoral contract.The structure-property relationship study of a series of cationic Ir(III) complexes in the form of [Ir(C^N)2(dtBubpy)]PF6 [where dtBubpy = 4,4′-ditert-butyl-2,2′- bipyridine and C^N = cyclometallating ligand bearing an electron-withdrawing group (EWG) at C4 of the phenyl substituent, i.e. -CF3 ( 1 ), -OCF3 ( 2 ), -SCF3 ( 3 ), -SO2CF3 ( 4 )] have been investigated. The physical and optoelectronic properties of the four complexes were comprehensively characterized, including by X-ray diffraction analysis. All the complexes exhibit quasi-reversible dtBubpy-based reductions from -1.29 V to -1.34 V (vs. SCE). The oxidation processes are likewise quasi-reversible (metal+C^N ligand) and are between 1.54- 1.72 V (vs. SCE). The relative oxidation potentials follow a general trend associated with the Hammett parameter (σ) of the EWGs. Surprisingly, complex 4 bearing the strongest EWG does not adhere to the expected Hammett behavior and was found to exhibit red-shifted absorption and emission maxima. Nevertheless, the concept of introducing EWGs was found to be generally useful in blue-shifting the emission maxima of the complexes (λem = 484-545 nm) compared to that of the prototype complex [Ir(ppy)2(dtBubpy)]PF6 (where ppy = 2- phenylpyridinato) (λem = 591 nm). The complexes were found to be bright emitters in solution at room temperature (ΦPL = 45-66%) with long excited-state lifetimes (τe = 1.14-4.28 μs). The photophysical properties along with Density Functional Theory (DFT) calculations suggest that the emission of these complexes originates from mixed contributions from ligand-centered (LC) transitions and mixed metal-to-ligand and ligand-to-ligand charge transfer (LLCT/MLCT) transitions, depending on the EWG. In complexes 1 , 3 and 4 the 3LC character is prominent over the mixed 3CT character while in complex 2 , the mixed 3CT character is much more pronounced, as demonstrated by DFT calculations and the observed positive solvatochromism effect. Due to the quasi-reversible nature of the oxidation and reduction waves, fabrication of light emitting electrochemical cells (LEECs) using these complexes as emitters was possible with the LEECs showing moderate efficiencies.Publisher PDFPeer reviewe
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