17,505 research outputs found

    UK and EU policy for approval of pesticides suitable for organic systems: Implications for Wales

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    This study was commissioned by the Welsh Assembly Government (WAG) to review the pesticide approval system in the UK and Europe as far as it affects the use of substances and techniques for crop protection by organic producers in Wales. WAG considers it important that the UK pesticide approval system does not present unnecessary barriers to the development of organic production in Wales. Key Recommendations and scope for further work · WAG should work with the Pesticides Safety Directorate to ensure that the development of pesticide regulatory policy at both National and European level takes full account of the needs of both conventional and organic agriculture and horticulture in the UK. · There is scope for WAG to support the development of a National Pesticide Policy so that regulatory and commercial barriers impeding the development of organic pesticides are minimised. Not only could greater availability of ‘organic pesticides’ have a significant impact on organic production in Wales but there could be important implications for conventional horticulture systems and the use of alternatives to conventional pesticides. · One important regulatory barrier to the registration of ‘organic pesticides’ is the MRL requirement(s) for their approval and this needs to be resolved. Suitable analytical techniques are required to determine firstly whether these substances result in residues, and secondly to identify the breakdown and residue pathways. So far, this issue has not received the attention of any EU Member State. · According to the proposed framework for the 4th Stage Review of EU Pesticides Directive 91/414, notifiers are required to produce a dossier, at their own expense, covering characterisation, human toxicity, ecotoxicity efficacy and other relevant data. The Review includes specific provision for companies notifying the same substance to submit a shared dossier. This will help those businesses (many of which are relatively small companies) to save on the high cost of producing the dossiers. It will also aid the Commission since it will reduce the number of dossiers that have to be considered, and ensure that all the available data is included. WAG should encourage and support the production of collective dossiers; although as yet there is no indication of how this will be done in practice, and further details from the Commission are awaited. · This study has concluded that access to a wider range of ‘organically acceptable pesticides’ would not have a dramatic impact on organic production in Wales. However, in developing an integrated organic policy, WAG should continue to address the pesticides issue. Some of the methods of pest & disease control in organic systems are either physical or multi-cellular e.g. micro-organisms used as biocontrol agents. WAG agri environment policy may provide a vehicle to promote these techniques much more actively. Further, it is important to recognise that while Wales alone is too small to have a major impact on commercial and regulatory pressures, WAG can have an impact by working pro-actively with others to make progress. · There are no published EU or national Member State criteria that can be used to evaluate the acceptability of pesticide substances for organic production. Identifying such criteria and promoting their acceptance at EU level and nationally would allow more active substances to be made available. WAG should work with PSD and others to identify appropriate criteria. · The specific provisions of Article 7 in Annex 2(b) of the Organic Regulation (2092/91) place potential barriers to the adoption of organically acceptable substances for crop protection. There are a number of potentially useful substances currently not included in the Organic Regulation e.g. potassium bicarbonate. WAG should work with PSD and others to identify such substances and support the production of appropriate dossiers. WAG could also encourage further dialogue between the organic sector and Defra to identify amendments in the Organic Regulations to facilitate the inclusion of new pesticides. · Organic pest and disease management is not just a question of inputs but it also relies crucially on advice and extension through initiatives such as Farming Connect and the work of Organic Centre Wales. Long-term commitment to supporting on going advice and extension activities is vital to promote and disseminate best practice in Welsh agriculture and horticulture. · Organic horticulture, vegetable and fruit production systems are particularly sensitive to pest and disease management. Successful control of pests, diseases (and weeds) in these sectors can be critical to the business, and is not assured even when all husbandry and management methods have been effectively applied. Consequently, the use of organically acceptable crop protection methods resulting from future developments (e.g. biopesticides, biological control agents) could have an important role in pest and disease management in these sectors. Both organic and conventional producers in Wales could benefit from having these options available to them and WAG could encourage the adoption of these approaches through appropriate Technology Transfer activities. · The way in which such substances will be regulated at a European level in future is evolving as the review of the Pesticide Directive 91/414 EEC enters the 4th Stage. This stage of the review includes (amongst others) those substances permitted for use in organic production. The guidance documents for the evaluation of applications on plant protection products made from plants or plant extracts and from chemical substances are currently at the draft stage. The response of the Pesticide Safety Directorate and Defra to these developments is not yet clear but this provides an excellent opportunity for WAG to have an input at an early stage in the review process

    Shifting the Quantum-Classical Boundary: Theory and Experiment for Statistically Classical Optical Fields

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    The growing recognition that entanglement is not exclusively a quantum property, and does not even originate with Schr\"odinger's famous remark about it [Proc. Camb. Phil. Soc. 31, 555 (1935)], prompts examination of its role in marking the quantum-classical boundary. We have done this by subjecting correlations of classical optical fields to new Bell-analysis experiments, and report here values of the Bell parameter greater than B=2.54{\cal B} = 2.54. This is many standard deviations outside the limit B=2{\cal B} = 2 established by the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality [Phys. Rev. Lett. 23, 880 (1969)], in agreement with our theoretical classical prediction, and not far from the Tsirelson limit B=2.828...{\cal B} = 2.828.... These results cast a new light on the standard quantum-classical boundary description, and suggest a reinterpretation of it.Comment: Comments and Remarks are warmly welcome! arXiv admin note: text overlap with arXiv:1406.333

    Continuous volumetric imaging via an optical phase-locked ultrasound lens

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    In vivo imaging at high spatiotemporal resolution is key to the understanding of complex biological systems. We integrated an optical phase-locked ultrasound lens into a two-photon fluorescence microscope and achieved microsecond-scale axial scanning, thus enabling volumetric imaging at tens of hertz. We applied this system to multicolor volumetric imaging of processes sensitive to motion artifacts, including calcium dynamics in behaving mouse brain and transient morphology changes and trafficking of immune cells

    A Comparative Study of the Magnitude, Frequency and Distribution of Intense Rainfall in the United Kingdom

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    During the 1960s, a study was made of the magnitude, frequency and distribution of intense rainfall over the UK, employing data from more than 120 daily-read rain gauges covering the period 1911 to 1960. Using the same methodology, that study was recently updated utilizing data for the period 1961 to 2006 for the same gauges, or from those nearby. This paper describes the techniques applied to ensure consistency of data and statistical modelling. It presents a comparison of patterns of extreme rainfalls for the two periods and discusses the changes that have taken place. Most noticeably, increases up to 20% have occurred in the north west of the country and in parts of East Anglia. There have also been changes in other areas, including decreases of the same magnitude over central England. The implications of these changes are considered

    Rapidly reconfigurable optically induced photonic crystals in hot rubidium vapor

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    Through periodic index modulation, we create two different types of photonic structures in a heated rubidium vapor for controlled reflection, transmission and diffraction of light. The modulation is achieved through the use of the AC Stark effect resulting from a standing-wave control field. The periodic intensity structures create translationally invariant index profiles analogous to photonic crystals in spectral regions of steep dispersion. Experimental results are consistent with modeling.Comment: 6 pages, 6 figure

    Characterizing and modeling backscattering in silicon microring resonators

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    This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.024980. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawWe present an experimental technique to characterize back-scattering in silicon microring resonators, together with a simple analytical model that reproduces the experimental results. The model can extract all the key parameters of an add-drop-type resonator, which are the loss, both coupling coefficients and backscattering. We show that the backscattering effect strongly affects the resonance shape, and that consecutive resonances of the same ring can have very different backscattering parameters. © 2011 Optical Society of America.The authors acknowledge financial support from the Spanish Ministry of Science and Innovation through contract SINADEC (TEC2008-06333). Joaquin Matres is supported by the Formacion de Personal Investigador grant program of the Universidad Politecnica de Valencia.Ballesteros García, G.; Matres Abril, J.; Martí Sendra, J.; Oton Nieto, CJ. (2011). Characterizing and modeling backscattering in silicon microring resonators. Optics Express. 19(25):24980-24985. https://doi.org/10.1364/OE.19.024980S24980249851925De Vos, K., Bartolozzi, I., Schacht, E., Bienstman, P., & Baets, R. (2007). Silicon-on-Insulator microring resonator for sensitive and label-free biosensing. Optics Express, 15(12), 7610. doi:10.1364/oe.15.007610Almeida, V. R., Barrios, C. A., Panepucci, R. R., & Lipson, M. (2004). All-optical control of light on a silicon chip. Nature, 431(7012), 1081-1084. doi:10.1038/nature02921Dumon, P., Bogaerts, W., Wiaux, V., Wouters, J., Beckx, S., Van Campenhout, J., … Baets, R. (2004). Low-Loss SOI Photonic Wires and Ring Resonators Fabricated With Deep UV Lithography. IEEE Photonics Technology Letters, 16(5), 1328-1330. doi:10.1109/lpt.2004.826025Morichetti, F., Canciamilla, A., Martinelli, M., Samarelli, A., De La Rue, R. M., Sorel, M., & Melloni, A. (2010). Coherent backscattering in optical microring resonators. Applied Physics Letters, 96(8), 081112. doi:10.1063/1.3330894Little, B. E., Laine, J.-P., & Chu, S. T. (1997). Surface-roughness-induced contradirectional coupling in ring and disk resonators. Optics Letters, 22(1), 4. doi:10.1364/ol.22.000004Kippenberg, T. J., Spillane, S. M., & Vahala, K. J. (2002). Modal coupling in traveling-wave resonators. Optics Letters, 27(19), 1669. doi:10.1364/ol.27.001669Zhang, Z., Dainese, M., Wosinski, L., & Qiu, M. (2008). Resonance-splitting and enhanced notch depth in SOI ring resonators with mutual mode coupling. Optics Express, 16(7), 4621. doi:10.1364/oe.16.004621Morichetti, F., Canciamilla, A., Ferrari, C., Torregiani, M., Melloni, A., & Martinelli, M. (2010). Roughness Induced Backscattering in Optical Silicon Waveguides. Physical Review Letters, 104(3). doi:10.1103/physrevlett.104.033902Little, B. E., Chu, S. T., Haus, H. A., Foresi, J., & Laine, J.-P. (1997). Microring resonator channel dropping filters. Journal of Lightwave Technology, 15(6), 998-1005. doi:10.1109/50.588673Morichetti, F., Canciamilla, A., & Melloni, A. (2010). Statistics of backscattering in optical waveguides. Optics Letters, 35(11), 1777. doi:10.1364/ol.35.001777McKinnon, W. R., Xu, D. X., Storey, C., Post, E., Densmore, A., Delâge, A., … Janz, S. (2009). Extracting coupling and loss coefficients from a ring resonator. Optics Express, 17(21), 18971. doi:10.1364/oe.17.01897

    The measurement of low pay in the UK labour force survey

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    Consideration of the National Minimum Wage requires estimates of the distribution of hourly pay. The UK Labour Force Survey (LFS) is a key source of such estimates. The approach most frequently adopted by researchers has been to measure hourly earnings from several questions on pay and hours. The Office for National Statistics is now applying a new approach, based on an alternative more direct measurement introduced in March 1999. These two measures do not produce identical values and this paper investigates sources of discrepancies and concludes that the new variable is more accurate. The difficulty with using the new variable is that it is only available on a subset of respondents. An approach is developed in which missing values of the new variable are replaced by imputed values. The assumptions underlying this imputation approach and results of applying it to LFS data are presented. The relation to weighting approaches is also discussed
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