IMAGING DIAGNOSIS—USE OF RADIOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF A MINERALIZED YOLK SAC IN A BROWN KIWI (APTERYX MANTELLI)          下载免费PDF全文

Paul Wightman  Eli B. Cohen  Stuart Hunter  Brett Gartrell 《Veterinary radiology & ultrasound》2015,56(4):E40-E43

A 12‐day‐old Brown Kiwi (Apteryx mantelli) was presented with anorexia, torticollis, head‐tilt, and coelomic distension. Radiographs showed an ill‐defined, fat‐opaque, coelomic mass displacing viscera craniodorsally. Curvilinear mineral opacities were superimposed over the ventral aspect of the mass. Computed tomography demonstrated the presence of mineral within the periphery of a fat attenuating mass consistent with a retained yolk sac. A deutectomy (yolk sac excision) was performed. Histopathology of the excised tissue confirmed the diagnosis of a retained yolk sac with multifocal mineralization.  相似文献   

Aconitase couples metabolic regulation to mitochondrial DNA maintenance     

Chen XJ  Wang X  Kaufman BA  Butow RA 《Science (New York, N.Y.)》2005,307(5710):714-717

Mitochondrial DNA (mtDNA) is essential for cells to maintain respiratory competency and is inherited as a protein-DNA complex called the nucleoid. We have identified 22 mtDNA-associated proteins in yeast, among which is mitochondrial aconitase (Aco1p). We show that this Krebs-cycle enzyme is essential for mtDNA maintenance independent of its catalytic activity. Regulation of ACO1 expression by the HAP and retrograde metabolic signaling pathways directly affects mtDNA maintenance. When constitutively expressed, Aco1p can replace the mtDNA packaging function of the high-mobility-group protein Abf2p. Thus, Aco1p may integrate metabolic signals and mtDNA maintenance.  相似文献   

Asparagine hydroxylation of the HIF transactivation domain a hypoxic switch   总被引：1，自引：0，他引：1  

Lando D  Peet DJ  Whelan DA  Gorman JJ  Whitelaw ML 《Science (New York, N.Y.)》2002,295(5556):858-861

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A robust design mark-resight abundance estimator allowing heterogeneity in resighting probabilities     

Brett T. McClintock  Gary C. White  Kenneth P. Burnham 《Journal of Agricultural, Biological & Environmental Statistics》2006,11(3):231-248

This article introduces the beta-binomial estimator (BBE), a closed-population abundance mark-resight model combining the favorable qualities of maximum likelihood theory and the allowance of individual heterogeneity in sighting probability (p). The model may be parameterized for a robust sampling design consisting of multiple primary sampling occasions where closure need not be met between primary occasions. We applied the model to brown bear data from three study areas in Alaska and compared its performance to the joint hypergeometric estimator (JHE) and Bowden’s estimator (BOWE). BBE estimates suggest heterogeneity levels were non-negligible and discourage the use of JHE for these data. Compared to JHE and BOWE, confidence intervals were considerably shorter for the AIC_c model-averaged BBE. To evaluate the properties of BBE relative to JHE and BOWE when sample sizes are small, simulations were performed with data from three primary occasions generated under both individual heterogeneity and temporal variation in p. All models remained consistent regardless of levels of variation in p. In terms of precision, the AIC_c model-averaged BBE showed advantages over JHE and BOWE when heterogeneity was present and mean sighting probabilities were similar between primary occasions. Based on the conditions examined, BBE is a reliable alternative to JHE or BOWE and provides a framework for further advances in mark-resight abundance estimation.  相似文献   

Using Cs measurements to validate the application of the AGNPS and ANSWERS erosion and sediment yield models in two small Devon catchments     

D. E. Walling  Q. He  P. A. Whelan 《Soil & Tillage Research》2003,69(1-2):27-43

Distributed erosion and sediment yield models are being increasingly used for predicting soil erosion and sediment yields in agricultural catchments. In most applications, validation of such models has commonly been restricted to comparison of the predicted and measured sediment output from a catchment, because spatially distributed information on rates and patterns of soil redistribution within the catchment has been lacking. However, such spatially distributed data are needed for rigorous model testing, in order to validate the internal functioning of a model and its applicability at different spatial scales. The study reported in this paper uses two approaches to test the performance of the agricultural non-point source pollution (AGNPS) and areal non-point source watershed environmental response simulation (ANSWERS) erosion and sediment yield models in two small catchments in Devon, UK. These involve, firstly, comparison of observed and predicted runoff and sediment output data for individual storm events monitored at the basin outlets and, secondly, information on the spatial pattern of soil redistribution within the catchments derived from ¹³⁷Cs measurements. The results obtained indicate that catchment outputs simulated by both models are reasonably consistent with the recorded values, although the AGNPS model appears to provide closer agreement between observed and predicted values. However, the spatial patterns of soil redistribution and the sediment delivery ratios predicted for the two catchments by the AGNPS and ANSWERS models differ significantly. Comparison of the catchment sediment delivery ratios and the pattern of soil redistribution in individual fields predicted by the models with equivalent information derived from ¹³⁷Cs measurements indicates that the AGNPS model provides more meaningful predictions of erosion and sediment yield under UK conditions than the ANSWERS model and emphasises the importance of using information on both catchment output and sediment redistribution within the catchment for model validation.  相似文献   

Potential Reservoirs and Risk Factors for VHSV IVb in an Enzootic System: Budd Lake,Michigan     

Elizabeth Throckmorton  Travis Brenden  Amber K. Peters  Tammy J. Newcomb  Gary E. Whelan  Mohamed Faisal 《Journal of aquatic animal health》2013,25(1):31-42

Abstract

Viral hemorrhagic septicemia virus genotype IVb (VHSV IVb) has caused major, sporadic fish die-offs in the Laurentian Great Lakes region of North America since 2005. Presently, factors affecting VHSV IVb persistence in enzootic systems are not well understood. Even with annual surveillance, the virus can go undetected for several years after an outbreak before again re-emerging, which suggests that the virus is maintained in the system either below detectable levels or in untested reservoirs. The aim of this study was to identify potential reservoirs of VHSV IVb in Budd Lake, Michigan; VHSV IVb was first detected in Budd Lake in 2007 but remained undetected until 2011. Additionally, we explored the susceptibility of naive fish introduced into a water body enzootic for VHSV IVb by stocking age-0 Largemouth Bass Micropterus salmoides at varying densities into enclosures in the lake. The virus was not detected among samples of the fishes Notropis spp. and Lepomis spp., cylindrical papershell mussels Anodontoides ferussacianus, leeches (subclass Hirudinea), sediment, or water. However, the virus was successfully isolated from amphipods (family Hyalellidae) and Largemouth Bass held in the enclosures. Our finding of VHSV IVb in Hyalellidae amphipods in combination with other research that has detected the virus in Diporeia spp., a large benthic amphipod important as a food resource to Great Lake fishes, suggests that benthic macroinvertebrates are a reservoir for VHSV IVb in infected systems. If there are environmental reservoirs for VHSV IVb in infected systems, they are likely unevenly distributed. Findings of this study add to our understanding of the seemingly complex ecology of this deadly and economically detrimental virus.

Received February 22, 2016; accepted October 16, 2016 Published online February 6, 2017  相似文献   

Novel expression of Haemonchus contortus vaccine candidate aminopeptidase H11 using the free-living nematode Caenorhabditis elegans     

Brett Roberts  Aristotelis Antonopoulos  Stuart M Haslam  Alison J Dicker  Tom N McNeilly  Stephanie L Johnston  Anne Dell  David P Knox  Collette Britton 《Veterinary research》2013,44(1):111

With the problem of parasitic nematode drug resistance increasing, vaccine development offers an alternative sustainable control approach. For some parasitic nematodes, native extracts enriched for specific proteins are highly protective. However, recombinant forms of these proteins have failed to replicate this protection. This is thought to be due to differences in glycosylation and/or conformation between native and recombinant proteins. We have exploited the free-living nematode Caenorhabditis elegans to examine its suitability as an alternative system for recombinant expression of parasitic nematode vaccine candidates. We focussed on Haemonchus contortus aminopeptidase H11 glycoprotein, which is enriched in a gut membrane fraction capable of inducing significant protection against this important ovine gastrointestinal nematode. We show that H. contortus H11 expressed in C. elegans is enzymatically active and MALDI mass spectrometry identifies similar di- and tri-fucosylated structures to those on native H11, with fucose at the 3- and/or 6-positions of the proximal GlcNAc. Some glycan structural differences were observed, such as lack of LDNF. Serum antibody to native H11 binds to C. elegans recombinant H11 and most of the antibody to rH11 or native H11 is directed to glycan moieties. Despite these similarities, no reduction in worm burden or faecal egg count was observed following immunisation of sheep with C. elegans-expressed recombinant H11 protein. The findings suggest that the di- and tri-fucosylated N-glycans expressed on rH11 do not contribute to the protective effect of H11 and that additional components present in native H11-enriched extract are likely required for enhancing the antibody response necessary for protection.  相似文献   

Impact of fire regimes,logging and topography on hollows in fallen logs in eucalypt forest of south eastern Australia     

Luke Collins  Ross A. Bradstock  Elizabeth M. Tasker  Robert J. Whelan 《Biological conservation》2012,149(1):23-31

Log hollows provide important habitat for a range of vertebrate fauna. Despite this, little is known about the impact fire regimes have on this resource, or the role topography may play in preserving hollows through the mitigation of fire intensity. This study examined the effect different combinations of fire frequency and topography have on (i) the number of hollow bearing logs and (ii) the presence and size of hollows within logs. The influence of wildfire severity and logging were also examined. Hollow availability (i.e. density of hollow bearing logs and hollow presence within logs) was greatest at sites burnt at ‘low’ frequency. The density of hollow logs was greater in gullies, though the effect of fire frequency did not vary with topographic position. Hollows showing signs of internal fire charring typically had a greater entrance width than unburnt hollows, which suggests fire plays an important role in creating large hollows. The number of hollow bearing logs increased with logging intensity, due to unmerchantable timber being left in situ. Wildfire severity had little effect on log hollows. The results indicate that frequent burning may reduce hollow availability, though it is likely that gullies will still retain a high density of hollow bearing logs irrespective of burning, and may play an important role in preserving connectivity of this resource across landscapes.  相似文献   

Evaluation of a local regression kriging approach for mapping apparent electrical conductivity of soil (ECa) at high resolution     

Wei Sun  Brett M. Whelan  Budiman Minasny  Alex B. McBratney 《植物养料与土壤学杂志》2012,175(2):212-220

Apparent electrical conductivity of soil (ECa) is a property frequently used as a diagnostic tool in precision agriculture, and is measured using vehicle‐mounted proximal sensors. Crop‐yield data, which is measured by harvester‐mounted sensors, is usually collected at a higher spatial density compared to ECa. ECa and crop‐yield maps frequently exhibit similar spatial patterns because ECa is primarily controlled by the soil clay content and the interrelated soil moisture content, which are often significant contributors to crop‐yield potential. By quantifying the spatial relationship between soil ECa and crop yield, it is possible to estimate the value of ECa at the spatial resolution of the crop‐yield data. This is achieved through the use of a local regression kriging approach which uses the higher‐resolution crop‐yield data as a covariate to predict ECa at a higher spatial resolution than would be prudent with the original ECa data alone. The accuracy of the local regression kriging (LRK) method is evaluated against local kriging (LK) and local regression (LR) to predict ECa. The results indicate that the performance of LRK is dependent on the performance of the inherent local regression. Over a range of ECa transect survey densities, LRK provides greater accuracy than LK and LR, except at very low density. Maps of the regression coefficients demonstrated that the relationship between ECa and crop yield varies from year to year, and across a field. The application of LRK to commercial scale ECa survey data, using crop yield as a covariate, should improve the accuracy of the resultant maps. This has implications for employing the maps in crop‐management decisions and building more robust calibrations between field‐gathered soil ECa and primary soil properties such as clay content.  相似文献   

Family Forest Owners’ Perceptions of Landowner Assistance Programs in the USA: A Qualitative Exploration of Program Impacts on Behaviour     

Kyle Andrejczyk  Brett J. Butler  Brenton J. Dickinson  Jaketon H. Hewes  Marla Markowski-Lindsay  David B. Kittredge  Michael A. Kilgore  Stephanie A. Snyder  Paul F. Catanzaro 《Small-Scale Forestry》2016,15(1):17-28

Using data collected from a series of focus groups, this study examines how landowner assistance programs (which may include management plans, cost-share, technical assistance and advice, and education components) affect family forest owner behaviour in the USA. Not surprisingly, most owners who participated in assistance programs had pre-existing management objectives. Participation in the management plan and cost-share components was found to facilitate the stewardship of private forests by assisting and reinforcing the behaviour of those landowners who already intend to manage their land in some pre-conceived manner. Advice and educational components appeared to do more in terms of introducing owners to new ideas. The mix of components offered as part of a landowner assistance program should consider the goals of the program and which components will be most effective in achieving those goals.  相似文献