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排序方式: 共有337条查询结果,搜索用时 250 毫秒
81.
Simulation of foot-and-mouth disease spread within an integrated livestock system in Texas, USA 总被引:1,自引:0,他引:1
Michael P. Ward Linda D. Highfield Pailin Vongseng M. Graeme Garner 《Preventive veterinary medicine》2009,88(4):286-297
We used a simulation study to assess the impact of an incursion of foot-and-mouth disease (FMD) virus on the livestock industries in an 8-county area of the Panhandle region of Texas, USA. The study was conducted in a high-density livestock area, with an estimated number of cattle on-feed of approximately 1.8 million. We modified an existing stochastic, spatial simulation model to simulate 64 scenarios for planning and decision-making. Our scenarios simulated four different herd types for the index herd (company feedlot, backgrounder feedlot, large beef, backyard) and variations in three mitigation strategies (time-of-detection, vaccine availability, and surveillance during disease control). Under our assumptions about availability of resources to manage an outbreak, median epidemic lengths in the scenarios with commercial feedlot, backgrounder feedlot, large beef and backyard index herd types ranged from 28 to 52, 19 to 39, 18 to 32, and 18 to 36 days, respectively, and the average number of herds depopulated ranged from 4 to 101, 2 to 29, 1 to 15 and 1 to 18, respectively. Early detection of FMD in the index herd had the largest impact on reducing (13–21 days) the length of epidemics and the number of herds (5–34) depopulated. Although most predicted epidemics lasted only 1–2 months, and <100 herds needed to be depopulated, large outbreaks lasting 8–9 months with up to 230 herds depopulated might occur. 相似文献
82.
Graeme P. Elliott 《Biological conservation》2010,143(9):2119-2126
Common, widespread species are important for ecosystem structure and function. Although such species have declined in some parts of the world, for most ecosystems there is a lack of information about changes in the population status of common species. We studied the abundance of common, widespread forest birds in Nelson Lakes National Park, New Zealand using standardised 5-min bird counts, carried out over a 30-year time span. There was a significant change in the bird community structure during this period. Five native species (bellbird, rifleman, grey warbler, New Zealand tomtit and tui) declined in abundance during the 30 years. All of these declined in abundance at low but not high altitudes, and the decline was substantial for all but New Zealand tomtit and tui. Three other native species increased in abundance (silvereye, yellow-crowned parakeet and New Zealand robin). There was no change in the abundance of introduced blackbirds. We suggest that invasive alien species are the most likely cause of the ongoing declines in common native species. A peak in brushtail possum abundance and the arrival of a new species of Vespula wasp were two large changes in Nelson Lakes forests that occurred during this study. Both are likely to have added to the ongoing impacts of predation by introduced rats and stoats. We suggest that it is necessary to actively manage introduced species in order to maintain populations of widespread, common native bird species in New Zealand. 相似文献
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Michael Zuykov Bassem Allam Michel Gosselin Philippe Archambault Graeme Spiers Michael Schindler 《Journal of fish diseases》2020,43(7):775-778
In August 2019, visual inspection of intertidal zones of the Gulf of Maine (ME, USA) revealed young and adult wild blue mussels, Mytilus spp., in Alley Bay (Jonesport area) with the distinctive L-shaped shell deformity (LSSD) and green spots (GS) in the mantle and adductor muscle. LSSD is a characteristic sign of current or previous mussel infection by photosynthetic unicellular alga from the group Coccomyxa, while GS are algal colonies. Based on these findings, this study represents the first report of infection signs by pathogenic Coccomyxa-like algae in mussels from the coastal waters of the Northeastern United States, providing a base for future large scale monitoring of the alga in the region. 相似文献
86.
Identification of a spatially efficient portfolio of priority conservation sites in marine and estuarine areas of Florida 总被引:1,自引:0,他引:1
Laura Geselbracht Roberto Torres Graeme S. Cumming Daniel Dorfman Michael Beck Douglas Shaw 《水产资源保护:海洋与淡水生态系统》2009,19(4):408-420
- 1. A systematic conservation planning approach using benthic habitat and imperilled species data along with the site prioritization algorithm, MARXAN, was used to identify a spatially efficient portfolio of marine and estuarine sites around Florida with high biodiversity value.
- 2. Ensuring the persistence of an adequate geographic representation of conservation targets in a particular area is a key goal of conservation. In this context, development and testing of different approaches to spatially‐explicit marine conservation planning remains an important priority.
- 3. This detailed case study serves as a test of existing approaches while also demonstrating some novel ways in which current methods can be tailored to fit the complexities of marine planning.
- 4. The paper reports on investigations of the influence of varying several algorithm inputs on resulting portfolio scenarios including the conservation targets (species observations, habitat distribution, etc.) included, conservation target goals, and socio‐economic factors.
- 5. This study concluded that engaging stakeholders in the development of a site prioritization framework is a valuable strategy for identifying broadly accepted selection criteria; universal target representation approaches are more expedient to use as algorithm inputs, but may fall short in capturing the impact of historic exploitation patterns for some conservation targets; socio‐economic factors are best considered subsequent to the identification of priority conservation sites when biodiversity value is the primary driver of site selection; and the influence of surrogate targets on portfolio selection should be thoroughly investigated to ensure unintended effects are avoided.
- 6. The priority sites identified in this analysis can be used to guide allocation of limited conservation and management resources.
87.
The genome sequence of Drosophila melanogaster 总被引:2,自引:0,他引:2
Adams MD Celniker SE Holt RA Evans CA Gocayne JD Amanatides PG Scherer SE Li PW Hoskins RA Galle RF George RA Lewis SE Richards S Ashburner M Henderson SN Sutton GG Wortman JR Yandell MD Zhang Q Chen LX Brandon RC Rogers YH Blazej RG Champe M Pfeiffer BD Wan KH Doyle C Baxter EG Helt G Nelson CR Gabor GL Abril JF Agbayani A An HJ Andrews-Pfannkoch C Baldwin D Ballew RM Basu A Baxendale J Bayraktaroglu L Beasley EM Beeson KY Benos PV Berman BP Bhandari D Bolshakov S Borkova D Botchan MR Bouck J 《Science (New York, N.Y.)》2000,287(5461):2185-2195
The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes approximately 13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity. 相似文献
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Global biodiversity scenarios and landscape ecology 总被引:1,自引:0,他引:1
Graeme S. Cumming 《Landscape Ecology》2007,22(5):671-685
The composition of ecological communities is both cause and consequence of landscape pattern. Predicting biodiversity change
involves understanding not only ecology and evolution, but also complex changes in human societies and economies. Scenarios
offer a less rigid approach to thinking about biodiversity change in a policy and management context. They shift the focus
of research and management from making singular predictions and developing single ‘best’ strategies to exploring uncertainties
and assessing the outcomes of alternative policies. The four Millennium Ecosystem Assessment (MA) biodiversity scenarios illustrate
current approaches to biodiversity estimation in global scenarios. The MA biodiversity scenarios are built around the species–area
relationship and the magnitudes of a few area-dependent processes such as nitrogen deposition and climate change. Some of
the most obvious landscape-related omissions from the MA scenarios are pattern-process feedbacks, scale dependencies, and
the role of landscape configuration. While the MA has set a new standard for biodiversity scenarios, future exercises would
benefit from a more multi-scale and more mechanistic framework. I use examples from research on the landscape ecology and
biogeography of African ticks to illustrate how a hypothesis-based approach can be used to analyse the multi-scale, multi-level
drivers of change in patterns of species occurrences. Two of the most important challenges for the future development of both
landscape ecology and biodiversity scenarios are to become more mechanistic (less pattern-based) and more general (applicable
across different landscapes). 相似文献
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