3,605 research outputs found

    KMOS Data Flow: Reconstructing Data Cubes in One Step

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    KMOS is a multi-object near-infrared integral field spectrometer with 24 deployable pick-off arms. Data processing is inevitably complex. We discuss specific issues and requirements that must be addressed in the data reduction pipeline, the calibration, the raw and processed data formats, and the simulated data. We discuss the pipeline architecture. We focus on its modular style and show how these modules can be used to build a classical pipeline, as well as a more advanced pipeline that can account for both spectral and spatial flexure as well as variations in the OH background. A novel aspect of the pipeline is that the raw data can be reconstructed into a cube in a single step. We discuss the advantages of this and outline the way in which we have implemented it. We finish by describing how the QFitsView tool can now be used to visualise KMOS data.Comment: Contribution to "Ground-based and Airborne Instrumentation for Astronomy III', SPIE 7735-254 (June 2010). High resolution version can be found at http://spiedl.or

    Yersinia ruckeri isolates recovered from diseased Atlantic Salmon (Salmo salar) in Scotland are more diverse than those from Rainbow Trout (Oncorhynchus mykiss) and represent distinct subpopulations

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    Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease of farmed salmonids. Enteric redmouth disease is traditionally associated with rainbow trout (Oncorhynchus mykiss, Walbaum), but its incidence in Atlantic salmon (Salmo salar) is increasing. Yersinia ruckeri isolates recovered from diseased Atlantic salmon have been poorly characterized, and very little is known about the relationship of the isolates associated with these two species. Phenotypic approaches were used to characterize 109 Y. ruckeri isolates recovered over a 14-year period from infected Atlantic salmon in Scotland; 26 isolates from infected rainbow trout were also characterized. Biotyping, serotyping, and comparison of outer membrane protein profiles identified 19 Y. ruckeri clones associated with Atlantic salmon but only five associated with rainbow trout; none of the Atlantic salmon clones occurred in rainbow trout and vice versa. These findings suggest that distinct subpopulations of Y. ruckeri are associated with each species. A new O serotype (designated O8) was identified in 56 biotype 1 Atlantic salmon isolates and was the most common serotype identified from 2006 to 2011 and in 2014, suggesting an increased prevalence during the time period sampled. Rainbow trout isolates were represented almost exclusively by the same biotype 2, serotype O1 clone that has been responsible for the majority of ERM outbreaks in this species within the United Kingdom since the 1980s. However, the identification of two biotype 2, serotype O8 isolates in rainbow trout suggests that vaccines containing serotypes O1 and O8 should be evaluated in both rainbow trout and Atlantic salmon for application in Scotland

    Performance Assessment of an Energy Management System for a Home Microgrid with PV Generation

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    Home energy management systems (HEMS) are a key technology for managing future electricity distribution systems as they can shift household electricity usage away from peak consumption times and can reduce the amount of local generation penetrating into the wider distribution system. In doing this they can also provide significant cost savings to domestic electricity users. This paper studies a HEMS which minimizes the daily energy costs, reduces energy lost to the utility, and improves photovoltaic (PV) self-consumption by controlling a home battery storage system (HBSS). The study assesses factors such as the overnight charging level, forecasting uncertainty, control sample time and tariff policy. Two management strategies have been used to control the HBSS; (1) a HEMS based on a real-time controller (RTC) and (2) a HEMS based on a model predictive controller (MPC). Several methods have been developed for home demand energy forecasting and PV generation forecasting and their impact on the HEMS is assessed. The influence of changing the battery’s capacity and the PV system size on the energy costs and the lost energy are also evaluated. A significant reduction in energy costs and energy lost to the utility can be achieved by combining a suitable overnight charging level, an appropriate sample time, and an accurate forecasting tool. The HEMS has been implemented on an experimental house emulation system to demonstrate it can operate in real-time

    Artificial Light at Night Causes Top‐down and Bottom‐up Trophic Effects on Invertebrate Populations

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.1. Globally, many ecosystems are exposed to artificial light at night. Nighttime lighting has direct biological impacts on species at all trophic levels. However, the effects of artificial light on biotic interactions remain, for the most part, to be determined. 2. We exposed experimental mesocosms containing combinations of grassland plants and invertebrate herbivores and predators to illumination at night over a three-year period to simulate conditions under different common forms of street lighting. 3. We demonstrate both top-down (predation controlled) and bottom-up (resource controlled) impacts of artificial light at night in grassland communities. The impacts on invertebrate herbivore abundance were wavelength dependent and mediated via other trophic levels. 4. White LED lighting decreased the abundance of a generalist herbivore mollusc by 55% in the presence of a visual predator, but not in its absence, while monochromatic amber light (with a peak wavelength similar to low pressure sodium lighting) decreased abundance of a specialist herbivore aphid (by 17%) by reducing the cover and flower abundance of its main food plant in the system. Artificial white light also significantly increased the food plant’s foliar carbon to nitrogen ratio. 5. We conclude that exposure to artificial light at night can trigger ecological effects spanning trophic levels, and that the nature of such impacts depends on the wavelengths emitted by the lighting technology employed. 6. Policy implications. Our results confirm that artificial light at night, at illuminance levels similar to roadside vegetation, can have population effects mediated by both top-down and bottom-up effects on ecosystems. Given the increasing ubiquity of light pollution at night, these impacts may be widespread in the environment. These results underline the importance of minimising ecosystem disruption by reducing light pollution in natural and semi-natural ecosystems.The research leading to this paper was funded by the European Research Council under the European Union’s Seventh Framework programme (FP7/2007-2013)/ERC grant agreement no. 268504 to KJG

    Integrating Narcissus-derived galanthamine production into traditional upland farming systems

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    Alzheimer’s disease (AD) is a disorder associated with progressive degeneration of memory and cognitive function. Galantamine is a licenced treatment for AD but supplies of the plant alkaloid that it is produced from, galanthamine, are limited. This three-year system study tested the potential to combine Narcissus-derived galanthamine production with grassland-based ruminant production. Replicate plots of permanent pasture were prepared with and without bulbs of Narcissus pseudonarcissus sown as lines into the sward. Two different fertiliser regimes were imposed. The above-ground green biomass of N. pseudonarcissus was harvested in early spring and the galanthamine yield determined. In the second harvest year a split-plot design was implemented with lines of N. pseudonarcissus cut annually and biennially. All plots were subsequently grazed by ewes and lambs and animal performance recorded. Incorporation of N. pseudonarcissus into grazed permanent pasture had no detrimental effects on the health or performance of the sheep which subsequently grazed the pasture. There was no consistency to the effects of fertiliser rates on galanthamine yields. There was no difference in overall galanthamine yield if N. pseudonarcissus was cut biennially (1.64 vs. 1.75 kg galanthamine/ha for annual combined vs biennial cuts respectively; s.e.d = 0.117 kg galanthamine/ha; ns). This study verified the feasibility of a dual cropping approach to producing plant-derived galanthamine

    Physicians' prescribing preferences were a potential instrument for patients' actual prescriptions of antidepressants

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    OBJECTIVES: To investigate whether physicians' prescribing preferences were valid instrumental variables for the antidepressant prescriptions they issued to their patients. STUDY DESIGN AND SETTING: We investigated whether physicians' previous prescriptions of (1) tricyclic antidepressants (TCAs) vs. selective serotonin reuptake inhibitors (SSRIs) and (2) paroxetine vs. other SSRIs were valid instruments. We investigated whether the instrumental variable assumptions are likely to hold and whether TCAs (vs. SSRIs) were associated with hospital admission for self-harm or death by suicide using both conventional and instrumental variable regressions. The setting for the study was general practices in the United Kingdom. RESULTS: Prior prescriptions were strongly associated with actual prescriptions: physicians who previously prescribed TCAs were 14.9 percentage points (95% confidence interval [CI], 14.4, 15.4) more likely to prescribe TCAs, and those who previously prescribed paroxetine were 27.7 percentage points (95% CI, 26.7, 28.8) more likely to prescribe paroxetine, to their next patient. Physicians' previous prescriptions were less strongly associated with patients' baseline characteristics than actual prescriptions. We found no evidence that the estimated association of TCAs with self-harm/suicide using instrumental variable regression differed from conventional regression estimates (P-value = 0.45). CONCLUSION: The main instrumental variable assumptions held, suggesting that physicians' prescribing preferences are valid instruments for evaluating the short-term effects of antidepressants

    A hierarchical two-stage energy management for a home microgrid using model predictive and real-time controllers

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    This paper presents a hierarchical two-layer home energy management system to reduce daily household energy costs and maximize photovoltaic self-consumption. The upper layer comprises a model predictive controller which optimizes household energy usage using a mixed-integer linear programming optimization; the lower layer comprises a rule-based real-time controller, to determine the optimal power settings of the home battery storage system. The optimization process also includes load shifting and battery degradation costs. The upper layer determines the operating schedule for shiftable domestic appliances and the profile for energy storage for the next 24 h. This profile is then passed to the lower energy management layer, which compensates for the effects of forecast uncertainties and sample time resolution. The effectiveness of the proposed home energy management system is demonstrated by comparing its performance with a single-layer management system. For the same battery size, using the hierarchical two-layer home energy management system can achieve annual household energy payment reduction of 27.8% and photovoltaic self-consumption of 91.1% compared to using a single layer home energy management system. The results show the capability of the hierarchical home energy management system to reduce household utility bills and maximize photovoltaic self-consumption. Experimental studies on a laboratory-based house emulation rig demonstrate the feasibility of the proposed home energy management system

    Further Sunyaev-Zel'dovich observations of two Planck ERCSC clusters with the Arcminute Microkelvin Imager

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    We present follow-up observations of two galaxy clusters detected blindly via the Sunyaev-Zel'dovich (SZ) effect and released in the Planck Early Release Compact Source Catalogue. We use the Arcminute Microkelvin Imager, a dual-array 14-18 GHz radio interferometer. After radio source subtraction, we find a SZ decrement of integrated flux density -1.08+/-0.10 mJy toward PLCKESZ G121.11+57.01, and improve the position measurement of the cluster, finding the centre to be RA 12 59 36.4, Dec +60 04 46.8, to an accuracy of 20 arcseconds. The region of PLCKESZ G115.71+17.52 contains strong extended emission, so we are unable to confirm the presence of this cluster via the SZ effect.Comment: 4 tables, 3 figures, revised after referee's comments and resubmitted to MNRA

    Selective oxidation of methane to methanol via in situ H2O2 synthesis

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    The selective oxidation of methane to methanol, using H2O2 generated in situ from the elements, has been investigated using a series of ZSM-5-supported AuPd catalysts of varying elemental composition, prepared via a deposition precipitation protocol. The alloying of Pd with Au was found to offer significantly improved efficacy, compared to that observed over monometallic analogues. Complementary studies into catalytic performance toward the direct synthesis and subsequent degradation of H2O2, under idealized conditions, indicate that methane oxidation efficacy is not directly related to H2O2 production rates, and it is considered that the known ability of Au to promote the release of reactive oxygen species is the underlying cause for the improved performance of the bimetallic catalysts
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