Comparison of carbon-stock changes,eddycovariance carbon fluxes and model estimates in coastal Douglas-fir stands in British Columbia     

Colin J Ferster  JA 《中国林学(英文版)》2015,(2):104-122

Background: The global network of eddy-covariance(EC) flux-towers has improved the understanding of the terrestrial carbon(C) cycle, however, the network has a relatively limited spatial extent compared to forest inventory data and plots. Developing methods to use inventory-based and EC flux measurements together with modeling approaches is necessary evaluate forest C dynamics across broad spatial extents.Methods: Changes in C stock change(ΔC) were computed based on repeated measurements of forest inventory plots and compared with separate measurements of cumulative net ecosystem productivity(ΣNEP) over four years(2003 – 2006) for Douglas-fir(Pseudotsuga menziesii var menziesii) dominated regeneration(HDF00), juvenile(HDF88and HDF90) and near-rotation(DF49) aged stands(6, 18, 20, 57 years old in 2006, respectively) in coastal British Columbia. ΔC was determined from forest inventory plot data alone, and in a hybrid approach using inventory data along with litter fall data and published decay equations to determine the change in detrital pools. These ΔC-based estimates were then compared with ΣNEP measured at an eddy-covariance flux-tower(EC-flux) and modelled by the Carbon Budget Model- Canadian Forest Sector(CBM-CFS3) using historic forest inventory and forest disturbance data.Footprint analysis was used with remote sensing, soils and topography data to evaluate how well the inventory plots represented the range of stand conditions within the area of the flux-tower footprint and to spatially scale the plot data to the area of the EC-flux and model based estimates.Results: The closest convergence among methods was for the juvenile stands while the largest divergences were for the regenerating clearcut, followed by the near-rotation stand. At the regenerating clearcut, footprint weighting of CBM-CFS3 ΣNEP increased convergence with EC flux ΣNEP, but not for ΔC. While spatial scaling and footprint weighting did not increase convergence for ΔC, they did provide confidence that the sample plots represented site conditions as measured by the EC tower.Conclusions: Methods to use inventory and EC flux measurements together with modeling approaches are necessary to understand forest C dynamics across broad spatial extents. Each approach has advantages and limitations that need to be considered for investigations at varying spatial and temporal scales.  相似文献   

Identification of Apoptotic Bodies in Equine Semen     

AB Caselles  A Miro‐Moran  A Morillo Rodriguez  JM Gallardo Bolaños  C Ortega‐Ferrusola  GM Salido  FJ Peña  JA Tapia  IM Aparicio 《Reproduction in domestic animals》2014,49(2):254-262

Apoptosis in the testis is required to ensure an efficient spermatogenesis. However, sometimes, defective germ cells that are marked for elimination during this process escape elimination in the testes, giving rise to ejaculates with increased percentages of abnormal and apoptotic spermatozoa and a high percentage of apoptotic bodies. Apoptosis markers in the ejaculate have been associated with low fertility, either in animals or humans. Therefore, the goal of this study was to investigate whether fresh equine semen contains apoptotic bodies [initially named Merocyanine 540 (M540) bodies] and to study the relationship between the quantity of these bodies and cell concentration, the volume of ejaculate, viability and motility. Moreover, we also studied whether the presence apoptotic bodies in fresh semen was related to the resistance of the stallion spermatozoa to being incubated at 37°C or being frozen and thawed. Fresh equine semen was stained with fluorescent dyes such as M540 and Annexin‐V. Active Caspase 3 was studied in fresh semen through Western blotting and immunofluorescence with a specific antibody. Sperm kinematics was assessed in fresh, incubated and thawed samples using computer‐assisted semen analysis, and viability was evaluated with the LIVE/DEAD Sperm Viability Kit. Overall, our results demonstrate for the first time the presence of apoptotic bodies in equine semen. The quantity of apoptotic bodies was highly variable among stallions and was positively correlated with Caspase 3 activity in fresh samples and negatively correlated with the viability and motility of stallion spermatozoa after the cryopreservation process.  相似文献   

Anti‐Mullerian Hormone Concentration and Antral Ovarian Follicle Population in Murrah Heifers Compared to Holstein and Gyr Kept Under the Same Management     

JM Baldrighi  MF Sá Filho  EOS Batista  RNVR Lopes  JA Visintin  PS Baruselli  MEOA Assumpção 《Reproduction in domestic animals》2014,49(6):1015-1020

This study was performed to evaluate plasma concentrations of anti‐Mullerian hormone (AMH) and the ovarian antral follicle population (AFP) in different genetic groups. Cyclic heifers (13 Bubalus bubalis [Murrah]; 15 Bos taurus [Holstein] and 10 Bos indicus [Gyr]) were maintained under the same management and were synchronized with two doses of 150 μg IM d‐cloprostenol administered 14 days apart. After the second d‐cloprostenol treatment, heifers had their ovaries scanned daily by ultrasound to define the day of ovulation. On the same day, the AFP was determined and a plasma sample was collected to measure AMH. Murrah heifers had less AFP (25.6 ± 2.1 follicles; p = 0.01) and plasma AMH concentration (0.18 ± 0.03 ng/ml; p < 0.001) than Gyr (60.0 ± 12.2 follicles and 0.60 ± 0.12 ng/ml of AMH); however, data were similar when compared to Holstein (35.9 ± 6.8 follicles and 0.24 ± 0.06 ng/ml of AMH) heifers. Regardless of genetic background, there was a positive relationship between the AFP and plasmatic AMH concentration (Murrah [r = 0.62; p < 0.01], Holstein [r = 0.66; p < 0.001] and Gyr [r = 0.88; p < 0.001]). Also, when heifers were classified according to high‐ or low‐AMH concentration based on the average within each genetic group, high‐AMH heifers had greater (p < 0.0001) AFP than low‐AMH heifers. In conclusion, both Murrah and Holstein heifers presented lower plasma AMH concentration and AFP when compared to Gyr.  相似文献   

Reconstruction of Current Flow and Imaging of Current-Limiting Defects in Polycrystalline Superconducting Films     

AE Pashitski  A Gurevich  AA Polyanskii  DC Larbalestier  A Goyal  ED Specht  DM Kroeger  JA DeLuca  JE Tkaczyk 《Science (New York, N.Y.)》1997,275(5298):367-369

Magneto-optical imaging was used to visualize the inhomogeneous penetration of magnetic flux into polycrystalline TlBa2Ca2Cu3Ox films with high critical current densities, to reconstruct the local two-dimensional supercurrent flow patterns and to correlate inhomogeneities in this flow with the local crystallographic misorientation. The films have almost perfect c-axis alignment and considerable local a- and b-axis texture because the grains tend to form colonies with only slightly misaligned a and b axes. Current flows freely over these low-angle grain boundaries but is strongly reduced at intermittent colony boundaries of high misorientation. The local (<10-micrometer scale) critical current density Jc varies widely, being up to 10 times as great as the transport Jc (scale of approximately 1 millimeter), which itself varies by a factor of about 5 in different sections of the film. The combined experiments show that the magnitude of the transport Jc is largely determined by a few high-angle boundaries.  相似文献   

Pathologic fracture healing after femoral limb salvage in a dog     

MA Hayes  S Jemilo  P Muir  R Sullivan  JA Bleedorn 《Australian veterinary journal》2020,98(3):84-89

  相似文献   

Identification of toxigenic Pasteurella multocida in atrophic rhinitis of pigs by in vitro characterisation     

GJ EAMENS  PD KIRKLAND  MJ TURNER  JA GARDNER†  MP WHITE‡  CL HORNITZKY 《Australian veterinary journal》1988,65(4):120-123

Toxigenic strains of Pasteurella multocida were readily differentiated from non-toxigenic strains by an agarose overlay method using bovine turbinate cells or bovine lung cells. Cells which were young and densely confluent were best suited to this assay. The incubation period required to distinguish toxigenic strains was dependent on the confluence of the monolayers, which was affected by the seeding rate, cell passage level and growth time prior to overlay. The agarose overlay method correctly identified 11 of 11 reference strains of Pasteurella multocida, and visible cytotoxic changes were present in the monolayers after 48 to 65 h. Outbreaks of the enzootic form of atrophic rhinitis in 2 New South Wales piggeries were associated with the isolation of toxigenic type D strains of P. multocida.  相似文献   

Detection of Tritrichomonas foetus antigens in formalin-fixed, paraffin embedded sections by the peroxidase antiperoxidase technique     

CM CAMPERO  PW LADDS  RG HIRST  JA VAUGHAN  DE EMERY 《Australian veterinary journal》1989,66(8):264-266

  相似文献   

Use of hair root as a source of DNA for the detection of heterozygotes for recessive defects in cattle     

PJ HEALY  JA DENNIS  JF MOULE 《Australian veterinary journal》1995,72(10):392-392

  相似文献   

Idiopathic intranuclear inclusion bodies in the renal epithelium of macropods     

R. SPEARE  JA DONOVAN  LF SKERRATT  L. BERGER  PW LADDS  S.de  BEER 《Australian veterinary journal》1997,75(6):446-447

  相似文献   

Furazolidone toxicity in dairy calves     

JD TAYLOR  JA GIBSON  CEF YEATES 《Australian veterinary journal》1991,68(5):182-183

  相似文献