Fishing, trophic cascades, and the process of grazing on coral reefs   总被引：1，自引：0，他引：1  

Mumby PJ  Dahlgren CP  Harborne AR  Kappel CV  Micheli F  Brumbaugh DR  Holmes KE  Mendes JM  Broad K  Sanchirico JN  Buch K  Box S  Stoffle RW  Gill AB 《Science (New York, N.Y.)》2006,311(5757):98-101

Since the mass mortality of the urchin Diadema antillarum in 1983, parrotfishes have become the dominant grazer on Caribbean reefs. The grazing capacity of these fishes could be impaired if marine reserves achieve their long-term goal of restoring large consumers, several of which prey on parrotfishes. Here we compare the negative impacts of enhanced predation with the positive impacts of reduced fishing mortality on parrotfishes inside reserves. Because large-bodied parrotfishes escape the risk of predation from a large piscivore (the Nassau grouper), the predation effect reduced grazing by only 4 to 8%. This impact was overwhelmed by the increase in density of large parrotfishes, resulting in a net doubling of grazing. Increased grazing caused a fourfold reduction in the cover of macroalgae, which, because they are the principal competitors of corals, highlights the potential importance of reserves for coral reef resilience.  相似文献   

Age-dependent seroprevalence of antibodies against a Helicobacter pylori-like organism and Helicobacter pylori in commercially reared swine     

Ellis JA  Waldner CL  McIntosh KA  Rhodes C  Harding JC  Ringler SS  Krakowka S 《American journal of veterinary research》2006,67(11):1890-1894

OBJECTIVE: To determine the prevalence of antibodies against a swine-origin Helicobacter pylori-like organism (HPLO) and H pylori in conventionally reared swine. ANIMALS: 640 conventionally reared swine of various ages from 16 high-health farms in Canada, 20 sows from Ohio, and 35 gnotobiotic swine. PROCEDURES: Blood was collected from the cranial vena cava. Sera were collected and tested via ELISA for antibodies against antigen prepared from a swine-origin HPLO and human H pylori strain 26695. RESULTS: Antibodies reactive with a swine HPLO, H pylori, or both were detected in 483 of 640 swine from all 16 farms in western Canada. Seroprevalence varied with age and was low (5.6%) in suckling ( 4 weeks old to adulthood. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggested that colonization by a swine-origin HPLO, H pylori, or both and resultant seroconversion, like that of H pylori infection in humans, were common in commercial swine operations. Furthermore, data indicated that gastric infection was acquired at an early age. The relationships to gastric colonization by HPLOs and clinical manifestations of disease such as gastritis and gastroesophageal ulceration remain to be determined.  相似文献   

A gain-of-function polymorphism controlling complex traits and fitness in nature     

KV Prasad  BH Song  C Olson-Manning  JT Anderson  CR Lee  ME Schranz  AJ Windsor  MJ Clauss  AJ Manzaneda  I Naqvi  M Reichelt  J Gershenzon  SG Rupasinghe  MA Schuler  T Mitchell-Olds 《Science (New York, N.Y.)》2012,337(6098):1081-1084

Identification of the causal genes that control complex trait variation remains challenging, limiting our appreciation of the evolutionary processes that influence polymorphisms in nature. We cloned a quantitative trait locus that controls plant defensive chemistry, damage by insect herbivores, survival, and reproduction in the natural environments where this polymorphism evolved. These ecological effects are driven by duplications in the BCMA (branched-chain methionine allocation) loci controlling this variation and by two selectively favored amino acid changes in the glucosinolate-biosynthetic cytochrome P450 proteins that they encode. These changes cause a gain of novel enzyme function, modulated by allelic differences in catalytic rate and gene copy number. Ecological interactions in diverse environments likely contribute to the widespread polymorphism of this biochemical function.  相似文献   

Water-mediated proton hopping on an iron oxide surface     

Merte LR  Peng G  Bechstein R  Rieboldt F  Farberow CA  Grabow LC  Kudernatsch W  Wendt S  Lægsgaard E  Mavrikakis M  Besenbacher F 《Science (New York, N.Y.)》2012,336(6083):889-893

The diffusion of hydrogen atoms across solid oxide surfaces is often assumed to be accelerated by the presence of water molecules. Here we present a high-resolution, high-speed scanning tunneling microscopy (STM) study of the diffusion of H atoms on an FeO thin film. STM movies directly reveal a water-mediated hydrogen diffusion mechanism on the oxide surface at temperatures between 100 and 300 kelvin. Density functional theory calculations and isotope-exchange experiments confirm the STM observations, and a proton-transfer mechanism that proceeds via an H(3)O(+)-like transition state is revealed. This mechanism differs from that observed previously for rutile TiO(2)(110), where water dissociation is a key step in proton diffusion.  相似文献   

Clinical utility of a complete diagnostic protocol for the ocular evaluation of free-living raptors     

Labelle AL  Whittington JK  Breaux CB  Labelle P  Mitchell MA  Zarfoss MK  Schmidt SA  Hamor RE 《Veterinary ophthalmology》2012,15(1):5-17

Objective: To describe a protocol for the examination of free‐living raptors and report the ophthalmic examination findings of seven raptor species native to central Illinois, namely the barred owl, Cooper’s hawk, eastern screech owl, great horned owl, American kestrel, red‐tailed hawk, and turkey vulture and to determine if the findings relative to visual prognosis affected eligibility for future release. Animals studied: Seventy‐nine free‐living raptors. Procedures: Under manual restraint, complete ophthalmic examination including slit‐lamp biomicroscopy and indirect funduscopy, applanation tonometry, rebound tonometry, ocular morphometrics, B‐mode ultrasound, and electroretinography (ERG) were performed on each bird. Histopathology of enucleated globes was performed after euthanasia or death in selected cases. Results: The examination protocol was easily performed using manual restraint alone on all birds. Ocular lesions were detected in 48.1% of birds, with 47.3% affected unilaterally and 52.6% affected bilaterally. Ocular lesions were considered to be vision threatening in 29.0% of the unilaterally affected birds and 29.0% of the bilaterally affected birds. The most common case outcomes were discharge from hospital to rehabilitation facility (45.6%) followed by euthanasia (43.0%). The presence of an ocular lesion or a vision‐threatening ocular lesion was not significantly associated with outcome. Reference ranges are reported for B‐mode ultrasound, ocular morphometrics, and horizontal corneal diameter in all species. Conclusion: Complete ophthalmic examination can be supplemented by the use of ocular morphometrics, ultrasound, and ERG in the manually restrained raptor. These advanced diagnostic techniques may be useful in developing more objective criteria for evaluating eligibility for release following rehabilitation of free‐living birds of prey.  相似文献   

Electrophysiological studies in American Quarter horses with neuroaxonal dystrophy     

Finno CJ  Aleman M  Ofri R  Hollingsworth SR  Madigan JE  Winfield L  Bannasch DL 《Veterinary ophthalmology》2012,15(Z2):3-7

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Earthworm populations in septic system filter fields and potential effects on wastewater renovation   总被引：1，自引：0，他引：1  

Carrie L. Hawkins  Martin J. Shipitalo  E. Moye Rutledge  Mary C. Savin  Kristofor R. Brye 《Applied soil ecology》2008,40(1):195-200

Wastewater renovation in septic-system filter fields can be affected by preferential flow through soil macropores. Anecic earthworm species make deep vertical burrows that may reduce renovation by acting as preferential flow paths that decrease effluent contact with the soil matrix. On the other hand, endogeic earthworms make largely horizontal burrows that may enhance wastewater renovation by distributing the effluent over a larger area. Additionally, the moist, nutrient-rich environment in filter fields may increase earthworm populations by enhancing their survival. Therefore, our objectives were to determine earthworm numbers and biomass with distance from soil treatment trenches, and identify species present to estimate potential effects on wastewater renovation. Five septic systems were investigated. At each site, earthworm populations were measured using formalin extraction at 10 locations along each of three 7-m long transects perpendicular to the trenches. There were an average of 6.4 times more earthworms and 5.4 times more earthworm biomass within 1 m of the trench than in the background (3.5–7.0 m from the trenches) in 13 of the 15 transects. This suggests that earthworms may have a significant effect on the movement of effluent. Because only epigeic and endogeic species were observed, the potential for reduced renovation and groundwater contamination at these sites is likely low. This may not be the case in areas with large numbers of anecic earthworms.  相似文献   

Diagnostic Ophthalmology     

Sandmeyer LS  Breaux CB  Grahn BH 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(1):89-90

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Use of perioperative variables to determine the requirement for repeat celiotomy in horses with postoperative reflux after small intestinal surgery     

Carrie C. Jacobs  Darko Stefanovski  Louise L. Southwood 《Veterinary surgery : VS》2019,48(7):1204-1210

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Coding sequences of sarcoplasmic reticulum calcium ATPase regulatory peptides and expression of calcium regulatory genes in recurrent exertional rhabdomyolysis     

Stephanie J. Valberg  Kaitlin Soave  Zoë J. Williams  Sudeep Perumbakkam  Melissa Schott  Carrie J. Finno  Jessica L. Petersen  Clara Fenger  Joseph M. Autry  David D. Thomas 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2019,33(2):933-941

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