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- Bellm, Eric C., et al.
(författare)
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The Zwicky Transient Facility : System Overview, Performance, and First Results
- 2019
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Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 131:995
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Tidskriftsartikel (refereegranskat)abstract
- The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg(2) field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF's public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope.
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| 4. |
- Guillemain, Matthieu, et al.
(författare)
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Agent-based modeling may help to merge research traditions in foraging ecology in Europe and North America
- 2017
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Ingår i: Wildlife Society bulletin. - 0091-7648 .- 1938-5463. ; 41:1, s. 170-176
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Tidskriftsartikel (refereegranskat)abstract
- Although ducks have long been popular research subjects in both North America and Europe, geographical divergences in research orientation have developed during the past several decades for studying foraging ecology. In North America, foraging studies largely focused on the population level with an emphasis on foraging energetics aimed at improving waterfowl production through increased carrying capacity of wetlands in breeding areas, an approach later expanded to nonbreeding grounds. In Europe, studies have instead focused on inter-individual differences in behavior of foraging ducks, with an emphasis on individual efficiency (e.g., methods, intake rate, patch choice) within the framework of optimal foraging theory. We suggest that agent-based models (also termed individual-based behavior models), which aim to predict habitat use from the heterogeneous behavior of different individual agents, can help to unify these approaches and would benefit considerably from increased collaboration and integration of the approaches of both North American and European researchers.
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| 5. |
- Guillemain, Matthieu, et al.
(författare)
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Agent-based modeling may help to merge research traditions in foraging ecology in Europe and North America
- 2017
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Ingår i: Wildlife Society Bulletin. - : Wiley-Blackwell. - 0091-7648 .- 1938-5463. ; 41:1, s. 170-176
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Tidskriftsartikel (refereegranskat)abstract
- Although ducks have long been popular research subjects in both North America and Europe, geographical divergences in research orientation have developed during the past several decades for studying foraging ecology. In North America, foraging studies largely focused on the population level with an emphasis on foraging energetics aimed at improving waterfowl production through increased carrying capacity of wetlands in breeding areas, an approach later expanded to nonbreeding grounds. In Europe, studies have instead focused on inter-individual differences in behavior of foraging ducks, with an emphasis on individual efficiency (e.g., methods, intake rate, patch choice) within the framework of optimal foraging theory. We suggest that agent-based models (also termed individual-based behavior models), which aim to predict habitat use from the heterogeneous behavior of different individual agents, can help to unify these approaches and would benefit considerably from increased collaboration and integration of theapproaches of both North American and European researchers.
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| 6. |
- Guillemain, Matthieu, et al.
(författare)
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Foraging, nutrition, and energetics of waterfowl : a European perspective
- 2016
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Ingår i: 7th North American Duck Symposium.
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Konferensbidrag (refereegranskat)abstract
- Much attention has historically been devoted to feeding ecology of waterfowl, providing an extensive research record for Europe and North America alike. However, research in this field has gradually followed different paths on the two continents. American scientists have adopted a more applied perspective, often aiming at assessing the extent to which food requirements of waterfowl can be fulfilled in different habitats, and how management of these can increase carrying capacity. As opposed to this "energetic" approach, European scientists have rather framed their studies in a "behavioral" perspective, using waterfowl as model species for more theoretical approaches to foraging ecology. Consequently, while North American research has most often been carried out at the scale of waterfowl populations, the individual bird has more frequently been the scale of study in Europe. We present three examples of such European studies: first, a detailed analysis of the trade-offs made by dabbling ducks between foraging and anti-predator vigilance, leading to divergent strategies to face gradual food depletion during the winter. Second, we do a flyway-scale analysis of duck foraging needs and behavior, from Mediterranean wintering grounds to breeding sites in the Boreal, and point out the main hurdles faced by these birds across their annual cycle. Such detailed European studies can provide useful parameter values to fuel modern agent-based models of habitat use and carrying capacity developed in North America, hence cross-fertilizing the approaches on the two continents. This is exactly what our third example is about; namely adapting the SWAMP model developed in California to better understand and predict the use of harvested rice fields by wintering ducks in southern France.
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| 7. |
- Guillemain, Matthieu, et al.
(författare)
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Foraging, nutrition, and energetics of waterfowl : a European perspective
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Much attention has historically been devoted to feeding ecology of waterfowl, providing an extensive research record for Europe and North America alike. However, research in this field has gradually followed different paths on the two continents. American scientists have adopted a more applied perspective, often aiming at assessing the extent to which food requirements of waterfowl can be fulfilled in different habitats, and how management of these can increase carrying capacity. As opposed to this "energetic" approach, European scientists have rather framed their studies in a "behavioral" perspective, using waterfowl as model species for more theoretical approaches to foraging ecology. Consequently, while North American research has most often been carried out at the scale of waterfowl populations, the individual bird has more frequently been the scale of study in Europe. We present three examples of such European studies: first, a detailed analysis of the trade-offs made by dabbling ducks between foraging and anti-predator vigilance, leading to divergent strategies to face gradual food depletion during the winter. Second, we do a flyway-scale analysis of duck foraging needs and behavior, from Mediterranean wintering grounds to breeding sites in the Boreal, and point out the main hurdles faced by these birds across their annual cycle. Such detailed European studies can provide useful parameter values to fuel modern agent-based models of habitat use and carrying capacity developed in North America, hence cross-fertilizing the approaches on the two continents. This is exactly what our third example is about; namely adapting the SWAMP model developed in California to better understand and predict the use of harvested rice fields by wintering ducks in southern France.
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| 9. |
- Lewis, Stephen R., et al.
(författare)
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Effect of humidity, temperature and railhead contamination on the performance of friction modifiers : Pin-on-disk study
- 2013
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 227:F2, s. 115-127
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Tidskriftsartikel (refereegranskat)abstract
- Commercially available friction modifiers are used in many different countries that have widely different atmospheric conditions. These variations in atmospheric conditions lead to varying levels of railhead oxidation and debris build-up. Friction modifiers can be applied to the rail without any prior cleaning of the rail and this can lead to varying friction modifier/iron oxide ratios potentially affecting the performance of the friction modifier. This paper reports the results of an investigation that was performed to determine the effects of varying atmospheric and oxide conditions on the performance of friction modifiers. A pin-on-disk test rig with an attached environmental chamber was used for the study. Results show that relative humidity has a pronounced effect on the way in which the friction modifier affects friction levels, and also the amount of time it remains on the disk. This also depends on the concentration of oxide in the friction modifier. Glow discharge optical emission spectroscopy analysis was also carried out to assess the effect of the friction modifier and atmospheric conditions on the chemical composition of the surface of the disk. Results show that the depth of surface modification is vastly different depending on the conditions and level of railhead debris.
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