Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery          下载免费PDF全文

Allison Hoffman  Steve Sisler  Marie Pappania  Kimberly Hsu  Maya Ross  Ron Ofri 《Veterinary ophthalmology》2018,21(3):273-280

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Influence of Land-Use Legacies Following Shrub Reduction and Seeding of Big Sagebrush Sites     

Thomas A. Monaco  Allison Jones  Mary Pendergast  Eric T. Thacker  Linden Greenhalgh 《Strength and Conditioning Journal》2018,71(6):695-704

Big sagebrush (Artemisia tridentata Nutt.) plant communities often require management to reduce shrub density and rehabilitate understory vegetation. We studied vegetation responses to a two-way chain harrow treatment and broadcast seeding of 12 herbaceous species at eight Wyoming big sagebrush (A. tridentata Nutt. subsp. wyomingensis Beetle & Young) sites. These sites differed in land-use history; five were cultivated for dryland wheat production during the 1950 ? 1980s and then seeded with introduced forage grasses (C-S), while three had not been exposed to this land-use legacy (non C-S). Our objective was to evaluate whether the C-S legacy influences the magnitude of vegetation change following contemporary treatment. Before treatment, C-S sites had lower sagebrush cover, higher dead sagebrush cover, and higher broom snakeweed (Gutierrezia sarothrae [Pursh] Britton & Rusby) cover than adjacent non C-S sites. Plant community change 3 years after treatment, determined with multivariate ordination analysis of species composition, varied between site histories, and response to treatment was most strongly correlated with reductions in sagebrush cover, increases in perennial grasses, and increases in 10 other herbaceous species—including some undesirable species and four that were seeded in 2010. Five years after treatment, mature sagebrush cover remained reduced for both land-use histories, yet density of sagebrush seedlings and broom snakeweed increased in C-S sites during the second and third years after treatment. In addition, perennial forb cover increased for C-S sites, while perennial grass biomass increased for non C-S sites. Our results emphasize that broad variability in plant community responses to sagebrush reduction and seeding is possible within the same ecological site classification and that legacy effects due to the combination of past cultivation and seeding should be considered when planning restoration projects, including the consideration that seeding may not always be necessary on C-S sites.  相似文献   

A long-snouted predatory dinosaur from africa and the evolution of spinosaurids     

PC Sereno  AL Beck  DB Dutheil  B Gado  HCE Larsson  GH Lyon  JD Marcot  OWM Rauhut  RW Sadleir  CA Sidor  DD Varricchio  GP Wilson  JA Wilson 《Science (New York, N.Y.)》1998,282(5392):1298-1302

Fossils discovered in Lower Cretaceous (Aptian) rocks in the Tenere Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.  相似文献   

Tracking the long-term decline and recovery of an isolated population     

RL Westemeier  JD Brawn  SA Simpson  TL Esker  RW Jansen  JW Walk  EL Kershner  JL Bouzat  KN Paige 《Science (New York, N.Y.)》1998,282(5394):1695-1698

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.  相似文献   

Hunting behavior of a marine mammal beneath the antarctic fast Ice   总被引：1，自引：0，他引：1  

RW Davis  LA Fuiman  TM Williams  SO Collier  WP Hagey  SB Kanatous  S Kohin  M Horning 《Science (New York, N.Y.)》1999,283(5404):993-996

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.  相似文献   

New urban habitat for endangered humpback whales: San Francisco Bay     

Tim M. Markowitz  William Keener  Marc A. Webber  Allison R. Payne  Rebekah S. Lane  James A. Fahlbusch  John Calambokidis 《水产资源保护:海洋与淡水生态系统》2024,34(3):e4107

Filling a blank on the map: 60 years of fisheries in Equatorial Guinea          下载免费PDF全文

D. Belhabib  D. Hellebrandt Da Silva  E. H. Allison  D. Zeller  D. Pauly 《Fisheries Management and Ecology》2016,23(2):119-132

Despite a scarcity of pertinent information, it has been possible to reconstruct time series of marine fisheries catches for Equatorial Guinea from 1950 to 2010 using per capita fish consumption and population numbers for small‐scale fisheries, catch rates and number of vessels for industrial fisheries and discard rates to estimate the discarded bycatch. Small‐scale fisheries, industrial large‐scale fisheries, domestic and legal and illegal foreign fisheries and their discards are all included. Total catches were estimated at 2.7 million tonnes over the time period considered, of which 653 000 t were caught domestically compared to 187 000 t reported by FAO. This shows that fisheries have more importance for Equatorial Guinea's food security than the official data suggest. In contrast to what is suggested by official figures, fisheries were shown to be strongly impacted by civil and political unrest; notably, they declined overall because of civil and political conflicts, socio‐demographic dynamics, and a growing role of the newly discovered oil resources, which directly and indirectly threaten the food security of the people of Equatorial Guinea.  相似文献   

Abiotic conditions and plant cover differentially affect microbial biomass and community composition on dune gradients     

T.K. Rajaniemi  V.J. Allison 《Soil biology & biochemistry》2009,41(1):102-109

Dune systems are characterized by strong gradients of physical stress, with blowing sand and salt spray decreasing with distance from the ocean, and soil nutrients increasing. In this study we ask how soil microbial community composition and biomass change along transects away from the ocean, and whether these changes are regulated by abiotic stress or by resource availability. We collected bulk soil from under three plant species representative of the dune front, back, and flat: Ammophila breviligulata, Rosa rugosa, and Myrica pensylvanica. The biomass and composition of microbial communities were examined using phospholipid fatty acid (PLFA) analysis under patches of dominant vegetation, and in paired bare plots. We found that microbial biomass was strongly correlated with soil C, and thus the presence of vegetation. Community composition, on the other hand, varied with abiotic stresses, especially soil salinity. These variables in turn depended on distance from the shore, and were ameliorated in some cases by vegetation. These findings demonstrate that biomass and community composition are influenced by different environmental variables. Thus, relationships between biomass and composition are unlikely to be readily predicted on the basis of a single resource.  相似文献   

Light and electron microscopic evaluation of canine corneal endothelium following CO₂ photokeratotomy     

Allison Hoffman  Charlotte Ownby†  Terry W. Lehenbauer†  Don Samuelson§  Margi Gilmour†  Kenneth Bartels† 《Veterinary ophthalmology》2009,12(S1):28-34

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Rights‐based fisheries governance: from fishing rights to human rights     

Edward H Allison  Blake D Ratner  Björn Åsgård  Rolf Willmann  Robert Pomeroy  John Kurien 《Fish and Fisheries》2012,13(1):14-29

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