1,062 research outputs found

    Nozzle Classification for Drift Reduction in Orchard Spraying: Identification of Drift Reduction Class Threshold Nozzles

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    In fruit growing high values of spray drift are found compared to arable field applications. In arable spraying drift reducing nozzles are certified for use as drift reducing measures. The nozzles which may potentially reduce drift in fruit growing are not jet classified as drift reducing nozzles, although they are available on the market. The development of a nozzle classification system to identify the drift reduction potential of spray nozzles used in fruit crop spraying would open this market. The results of the initial setup of a nozzle classification system for spray drift reduction in orchard spraying based on drop size measurements is described. An evaluation was made of measured drop size characteristics of a series of nozzles in reference to performed field measurements of two characteristic nozzles; Albuz lilac and Lechler ID9001. Based on these anchor points the ranking of the volume fraction of drops smaller than 100 ¿m (V100) of the nozzle to be classified could be scaled to yield a potential drift reduction, assuming a linear relationship between V100 and spray drift deposition. Within this system, the determination of threshold nozzles for the drift reduction classes 50%, 75%, 90% and 95% drift reduction are described. Identified threshold nozzles for these classes are TeeJet DG8002, Albuz AVI 80015, Lechler ID9001 and Albuz TVI80025 all at 7 bar spray pressure, except for the Lechler ID 9001 which is used at 5 bar pressure. These nozzles will be used in field drift measurements to validate the mode

    Development of a Crop Adapted Spray Application (CASA) sprayer for orchards

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    In the EU-FP6 ISAFRUIT project a Crop Adapted Spray Application system (CASA) for precision crop protection was developed (Doruchowski et al., 2009). The system ensures efficient and safe spray application in orchards according to actual needs and with respect to the environment. The developed CASA system consist of three sub-systems: Crop Health Sensor (CHS) - identifying the health status of fruit crops to apply chemicals only when necessary; Crop Identification System (CIS) - identifying the tree canopy size and density to apply spray precisely at relevant doses; Environmentally Dependent Application Systems (EDAS) - identifying environmental circumstances and navigating the sprayer to adjust application parameters accordingly so that spray drift is minimised and direct water contamination is avoided

    Identification and quantification of point sources of surface water contamination in fruit culture in the Netherlands

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    Measurements of pesticide concentrations in surface water by the water boards show that they have decreased less than was expected from model calculations. Possibly, the implementation of spray drift reducing techniques is overestimated in the model calculation. The impact of point sources is probably underestimated. A project was initiated for the quantification and qualification of possible point sources in Dutch fruit culture. From a survey it was concluded that the majority of fruit growers do not posses the mandatory equipment regarding filling and cleaning of sprayers. This creates a potential environmental risk for surface water contamination. Further research is focused on: internal and external cleaning of sprayers, environmental impact of the washings, discharge of transport water from fruit sorting installations, and bioremediation systems for processing contaminated water

    Population Size Structure and Feeding Biology of Bathynerita naticoidea Clarke 1989 (Gastropoda: Neritacea) from Gulf of Mexico Hydrocarbon Seeps

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    Bathynerita naticoidea is a numerically dominant gastropod in upper continental slope chemosynthetic communities of the northern Gulf of Mexico. A comparison of population size structure at four sites off Louisiana revealed site-specific differences in mean shell size consistent with different recruitment histories and growth rates. Where individuals grow to the largest size, population numbers are low and recruitment seems to be limited. Where individuals grow to the smallest size, populations are high and recruitment seems to be high. These patterns appear to parallel the population size pattern of the beds of Bathymodiolus childressi Gustafson et. al. 1998 inhabited by the snail, which suggests a link between the control of the two. Analysis of gut contents and fecal matter of B. naticoidea and the organic film on the shell surface of B. childressi confirmed initial assumptions that the snail feeds by radular browsing. Free-living bacteria are abundant on mussel surfaces and are ingested by the snail. The presence of bacteria in the gut and feces was, however, lower, possibly because of dilution by mucus and digestion. It is proposed that B. childressi provides more than a passive surface for organic film development. The mussel may control the organic film development, thus controlling availability of food to the snail

    Ontwikkelingen schurftherkenning fruit

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    In het EU-FP6 ISAFruit-project wordt een Crop Adapted Spray Application-systeem voor precisiegewasbescherming in de fruitteelt ontwikkeld. Het systeem garandeert een veilige toediening van gewasbeschermingsmiddelen in boomgaarden afgestemd op de grootte van de boom en de geldende weersomstandigheden. Het systeem wordt beschreve

    Structural phase transition and material properties of few-layer monochalcogenides

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    GeSe and SnSe monochalcogenide monolayers and bilayers undergo a two-dimensional phase transition from a rectangular unit cell to a square unit cell at a temperature TcT_c well below the melting point. Its consequences on material properties are studied within the framework of Car-Parrinello molecular dynamics and density-functional theory. No in-gap states develop as the structural transition takes place, so that these phase-change materials remain semiconducting below and above TcT_c. As the in-plane lattice transforms from a rectangle onto a square at TcT_c, the electronic, spin, optical, and piezo-electric properties dramatically depart from earlier predictions. Indeed, the YY- and XX-points in the Brillouin zone become effectively equivalent at TcT_c, leading to a symmetric electronic structure. The spin polarization at the conduction valley edge vanishes, and the hole conductivity must display an anomalous thermal increase at TcT_c. The linear optical absorption band edge must change its polarization as well, making this structural and electronic evolution verifiable by optical means. Much excitement has been drawn by theoretical predictions of giant piezo-electricity and ferroelectricity in these materials, and we estimate a pyroelectric response of about 3×10123\times 10^{-12} C/KmC/K m here. These results uncover the fundamental role of temperature as a control knob for the physical properties of few-layer group-IV monochalcogenidesComment: Supplementary information included. Published versio

    The importance of being nimby; Een essay over burgerverzet en erfgoed

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    Dit essay is geschreven als statement naast alle feitelijke en verhelderende studies over burgerinitiatieven die eerder in deze reeks verschenen en nog zullen verschijnen. In een dialoog aan het einde van het essay maken we de (beleids)dilemma’s helder waar soms wel en soms nog geen oplossingen voor zij

    Методические подходы к оценке возможности реализации инновационных стратегий

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    Целью данной статьи является рассмотрение методических подходов к оценке возможности реализации инновационных стратегий

    General practitioners' accounts of negotiating antibiotic prescribing decisions with patients: a qualitative study on what influences antibiotic prescribing in low, medium and high prescribing practices

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    Background Antimicrobial resistance (AMR) is high on the UK public health policy agenda, and poses challenges to patient safety and the provision of health services. Widespread prescribing of antibiotics is thought to increase AMR, and mostly takes place in primary medical care. However, prescribing rates vary substantially between general practices. The aim of this study was to understand contextual factors related to general practitioners’ (GPs) antibiotic prescribing behaviour in low, high, and around the mean (medium) prescribing primary care practices. Methods Qualitative semi-structured interviews were conducted with 41 GPs working in North-West England. Participants were purposively sampled from practices with low, medium, and high antibiotic prescribing rates adjusted for the number and characteristics of patients registered in a practice. The interviews were analysed thematically. Results This study found that optimizing antibiotic prescribing creates tensions for GPs, particularly in doctor-patient communication during a consultation. GPs balanced patient expectations and their own decision-making in their communication. When not prescribing antibiotics, GPs reported the need for supportive mechanisms, such as regular practice meetings, within the practice, and in the wider healthcare system (e.g. longer consultation times). In low prescribing practices, GPs reported that increasing dialogue with colleagues, having consistent patterns of prescribing within the practice, supportive practice policies, and enough resources such as consultation time were important supports when not prescribing antibiotics. Conclusions Insight into GPs’ negotiations with patient and public health demands, and consistent and supportive practice-level policies can help support prudent antibiotic prescribing among primary care practices
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