853 resultados para 070301 Agro-ecosystem Function and Prediction
Resumo:
This is a report on a workshop held at Cambridge University Engineering Design Centre, 17-10 June 1992. This workshop was held to discuss the issue of 'function' and 'function-to-form' evolution in mechanical design. The authors organised this workshop as they felt that their understanding of these topics was incomplete and that discussions between researchers might help to clarify some key issues.
The topic chosen for the workshop proved to be a stimulating one. The term 'function' is part of a designer's daily vocabulary, however there is poor agreement about its definition. In order to develop computer systems to support product evolution, a precise definition is required. Further the value of 'function' and 'function-to-form' evolution as a good choice of workshop topic is evident from the lack of firm conclusions that resulted from the sessions. This lack of consensus made for lively discussion and left participants questioning many of their preconceived ideas.
Attendance at the workshop was by invitation only. A list of the participants (not all those invited could attend due to time and financial constraints) is given in Appendix 1.
Effect of work function and surface microstructure on field emission of tetrahedral amorphous carbon
Resumo:
This cruise report is a summary of a field survey conducted along a portion of the U.S. continental shelf in northwestern Gulf of Mexico (GOM), at navigable depths along the coastline seaward to the shelf break (~100m) from about 89°30' W to 95°28' W longitude, August 8 – 16, 2011 on NOAA Ship Nancy Foster Cruise NF-11-07-RACOW. Synoptic sampling of multiple ecological indicators was conducted at each of 34 stations throughout these waters using a random probabilistic sampling design. The original study design consisted of 50 stations extending from the Mississippi delta all the way to the U.S./Mexican border, but vessel failures precluded sampling at 16 stations within the western-most portion of the study area. At each station samples were collected for the analysis of benthic community structure and composition; concentrations of chemical contaminants in sediments and target demersal biota; sediment toxicity; nutrient and chlorophyll levels in the water column; and other basic habitat characteristics such as salinity, temperature, dissolved oxygen, turbidity, pH, sediment grain size, and organic carbon content. Other indicators, from a human-dimension perspective, were also recorded, including presence of vessels, oil rigs, surface trash, visual oil sheens in sediments or water, marine mammals, or noxious/oily sediment odors. The overall purpose of the survey was to collect data to assess the status of ecosystem condition and potential stressor impacts throughout the region, based on these various indicators and corresponding management thresholds, and to provide this information as a baseline for determining how such conditions may be changing with time. While sample analysis is still ongoing, some preliminary results and observations are reported here. A final report will be completed once all data have been processed.
Resumo:
Marine protected areas (MPAs) represent a form of spatial management, and geospatial information on living marine resources and associated habitat is extremely important to support best management practices in a spatially discrete MPA. Benthic habitat maps provide georeferenced information on the geomorphic structure and biological cover types in the marine environment. This information supports an enhanced understanding of ecosystem function and species habitat utilization patterns. Benthic habitat maps are most useful for marine management and spatial planning purposes when they are created at a scale that is relevant to management actions. We sought to improve the resolution of existing benthic habitat maps created during a regional mapping effort in Hawai`i. Our results complemented these existing regional maps and provided more detailed, finer-scale habitat maps for a network of MPAs in West Hawai`i. The map products created during this study allow local planners and managers to extract information at a spatial scale relevant to the discrete management units, and appropriate for local marine management efforts on the Kona Coast. The resultant benthic habitat maps were integrated in a geographic information system (GIS) that also included aerial imagery, underwater video, MPA regulations, summarized ecological data and other relevant and spatially explicit information. The integration of the benthic habitat maps with additional “value added” geospatial information into a dynamic GIS provide a decision support tool with pertinent marine resource information available in one central location and support the application of a spatial approach to the management of marine resources. Further, this work can serve as a case study to demonstrate the integration of remote sensing products and GIS tools at a fine spatial scale relevant to local-level marine spatial planning and management efforts.
Resumo:
This cruise report is a summary of a field survey conducted along the continental shelf of the northeastern Gulf of Mexico (GOM), encompassing 70,062 square kilometers of productive marine habitats located between the Mississippi Delta and Tampa Bay, August 13–21, 2010 on NOAA Ship Nancy Foster Cruise NF-10-09-RACOW. Synoptic sampling of multiple ecological indicators was conducted at each of 50 stations throughout these waters using a random probabilistic sampling design. At each station samples were collected for the analysis of benthic community structure and composition; concentrations of chemical contaminants (metals, pesticides, TPHs, PAHs, PCBs, PBDEs) in sediments and target demersal biota; sediment toxicity; nutrient and chlorophyll levels in the water column; and other basic habitat characteristics such as depth, salinity, temperature, dissolved oxygen, turbidity, pH, CDOM fluorescence, sediment grain size, and organic carbon content. Discrete water samples were collected just below the sea surface, in addition to any deeper subsurface depths where there was an occurrence of suspicious CDOM fluorescence signals, and analyzed for total BTEX/TPH and carcinogenic PAHs using immunoassay test kits. Other indicators of potential value from a human-dimension perspective were also recorded, including presence of any vessels, oil rigs, surface trash, visual oil sheens in sediments or water, marine mammals, or noxious/oily sediment odors. The overall purpose of the survey was to collect data to assess the status of ecosystem condition and potential stressor impacts throughout the region, based on these various indicators and corresponding management thresholds, and to provide this information as a baseline for determining how such conditions may be changing with time. In addition to the original project goals, both the scientific scope and general location of this project are relevant to addressing potential ecological impacts of the Deepwater Horizon oil spill. While sample analysis is still ongoing, a few preliminary results and observations are reported here. A final report will be completed once all data have been processed.