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71.
Practicable application of red sludge and melanterite (FeSO4) on bog peat soils A new way is shown to dispose the industrial by-products red sludge and melanterite by agricultural application. The ferrous products sorbe the moveable phosphates in the acid bog peat soil, so that they are still available for plants, but will not or only a little be leached. In a field trial the amount of leached phosphorus could be reduced by about 80%. The agricultural use of red sludge and melanterite is thereby at the same time a contribution to reduce the pollution of surface waters.  相似文献   
72.
The potential for genetic contamination of stocks arising from translocation and subsequent release or escape of translocated and/or genetically mixed stocks may be a significant risk to wild populations. In this context, we undertook a population genetic survey of stocks of lumpfish (Cyclopterus lumpus) along the Norwegian coast to establish the existing genetic population structure, which will aid the development of policy of the species’ use as cleaner fish in salmonid aquaculture. This was done by using 14 microsatellite loci and 287 specimens collected at five fishing grounds, covering most of the Norwegian coastline from south to north, with additional 18 samples of first-generation reared fish from a fish farm outside Tromsø (North Norway). Overall, there was no indication of significant spatial genetic structuring or of positive correlation between geographic and genetic distance among the wild lumpfish samples. These results suggest that, should translocated individuals escape from aquaculture in Norway, this will probably have little to no impact on the genetic composition of the local fish population.  相似文献   
73.

Key message

Tree heights in the central Congo Basin are overestimated using best-available height-diameter models. These errors are propagated into the estimation of aboveground biomass and canopy height, causing significant bias when used for calibration of remote sensing products in this region.

Context

Tree height-diameter models are important components of estimating aboveground biomass (AGB) and calibrating remote sensing products in tropical forests.

Aims

For a data-poor area of the central Congo Basin, we quantified height-diameter model performance of local, regional and pan-tropical models for their use in estimating AGB and canopy height.

Methods

At three old-growth forest sites, we assessed the bias introduced in height estimation by regional and pan-tropical height-diameter models. We developed an optimal local model with site-level randomizations accounted for by using a mixed-effects modeling approach. We quantified the error propagation of modeled heights for estimating AGB and canopy height.

Results

Regional and pan-tropical height-diameter models produced a significant overestimation in tree height, propagating into significant overestimations of AGB and Lorey’s height. The pan-tropical model accounting for climatic drivers performed better than the regional models. We present a local height-diameter model which produced nonsignificant errors for AGB and canopy height estimations at our study area.

Conclusion

The application of general models at our study area introduced bias in tree height estimations and the derived stand-level variables. Improved delimitation of regions in tropical Africa with similar forest structure is needed to produce models fit for calibrating remote sensing products.
  相似文献   
74.
Between January and April 2007, 424 calves under 22 days of age from 108 Dutch dairy herds were sampled to estimate the prevalence of non-normal faeces (‘custard-like’—yellowish-coloured with custard consistency or diarrhoea: watery-like faeces) and the shedding of enteropathogens Escherichia coli K99 (E. coli), Coronavirus, Cryptosporidium parvum (C. parvum), Rotavirus and Clostridium perfringens (Cl. perfringens). In addition, information was collected on animal characteristics and herd-management practices. The probability of detecting each one of five enteropathogens given a calf with ‘custard-like’ faeces or diarrhoea was estimated using Bayes’ rule and was based on the predicted probabilities from a multinominal model including each of five enteropathogens as independent variables. In addition, putative risk factors for the presence of each of five enteropathogens were analysed using logistic regression models with random herd effects.Fifty-seven percent of calves had faeces of normal colour (brownish) and consistency (firm), 23.8% (95%CI: 19.8–28.2%) had ‘custard-like’ faeces and 19.1% (95%CI: 15.5–23.2%) had diarrhoea. E. coli was the least detected enteropathogen (2.6% (95%CI: 1.3–4.6%) of calves, 9% (95%CI: 5–16%) of herds) and Cl. perfringens was most detected (54.0% (95%CI: 49.1–58.8%) of calves, 85% (95%CI: 77–91%) of herds). E. coli and Coronavirus were detected incidentally in only one or two calves per herd, whereas C. parvum and Cl. perfringens were frequently detected in up to four calves per herd. For calves with ‘custard-like’ faeces, the probability of detecting Rotavirus from a calf in its first week of age was 0.31 whereas for a calf in its second week, there was a 0.66 probability of detecting C. parvum. The probabilities of detecting E. coli, Rotavirus and C. parvum in calves with diarrhoea in their first week of age were 0.10, 0.20 and 0.43, respectively. In calves with diarrhoea between 1 and 2 weeks of age, the probability of detecting enteropathogens was 0.43 for C. parvum. None of the tested enteropathogens were related to ‘custard-like’ faeces or diarrhoea in the third week of age.Putative risk factors for E. coli, Coronavirus and C. parvum included the presence of peer-calves shedding Coronavirus, C. parvum or Rotavirus, respectively. Additionally, managerial risk factors such as non-optimal hygienic housing (for Coronavirus) and the routine use of antibiotics for diarrhoeic calves (for C. parvum) were found. No animal or managerial factors were associated with shedding of Cl. perfringens.  相似文献   
75.
Mantle peridotites drilled from the Izu-Bonin-Mariana forearc have unradiogenic 187Os/188Os ratios (0.1193 to 0.1273), which give Proterozoic model ages of 820 to 1230 million years ago. If these peridotites are residues from magmatism during the initiation of subduction 40 to 48 million years ago, then the mantle that melted was much more depleted in incompatible elements than the source of mid-ocean ridge basalts (MORB). This result indicates that osmium isotopes record information about ancient melting events in the convecting upper mantle not recorded by incompatible lithophile isotope tracers. Subduction zones may be a graveyard for ancient depleted mantle material, and portions of the convecting upper mantle may be less radiogenic in osmium isotopes than previously recognized.  相似文献   
76.
Shear-wave splitting across the fast-spreading East Pacific Rise has been measured from records of SKS and SKKS phases on the ocean-bottom seismometers of the Mantle Electromagnetic and Tomography (MELT) Experiment. The direction of fast shear-wave polarization is aligned parallel to the spreading direction. Delay times between fast and slow shear waves are asymmetric across the rise, and off-axis values on the Pacific Plate are twice those on the Nazca Plate. Splitting on the Pacific Plate may reflect anisotropy associated with spreading-induced flow above a depth of about 100 km, as well as a deeper contribution from warm asthenospheric return flow from the Pacific Superswell region.  相似文献   
77.
78.
High resolution computed tomography (CT) is a noninvasive imaging modality that has been used extensively in evaluating diseases of the human lumbosacral spine. Excellent spatial and contrast resolution, combined with multiplanar reformatting capability make high resolution CT scanners well-suited for similar applications in dogs. Consistently good quality images can be obtained when careful attention is given to factors affecting resolution. This paper reviews and illustrates some principles of high resolution CT, and proposes a technique for regional CT examination of the canine lumbosacral spine.  相似文献   
79.
Streptococcus suis serotypes associated with disease in weaned pigs   总被引:5,自引:0,他引:5  
Streptococcus suis was recovered from 9 outbreaks of septicaemia and meningitis in weaned pigs between 1979 and 1983. Fifteen isolates from 7 outbreaks were identified as S. suis type 9, and 3 isolates from 2 outbreaks as S. suis type 2. Three further isolates of S. suis type 2 and an isolate of S. suis type 3 were recovered from cases of bronchopneumonia in weaned pigs from 4 other piggeries.  相似文献   
80.
The aim of this study was to determine whether evidence could be obtained of foetal infection with Leptospira interrogans serovar hardjo in aborted foetuses collected from dairy farms. Material from 197 abortions occurring over a wide area of Victoria was collected over 3 years. None of 195 foetal kidney cultures or 7 cultures from membranes was positive for leptospiral organisms. Immunogold silver staining for leptospires was performed on sections of kidneys, lungs or heart from 156 foetuses, with negative results. Evidence of transient leptospiral infection in 11 of 123 foetuses was obtained by foetal heart blood serology. Two isolates of L. interrogans serovar hardjo were obtained from the urine of milking cows. These strains were examined by restriction endonuclease analysis and both were shown to be of the genotype Hardjobovis, as have been all Australian isolates studied so far. It appears that foetal infection with serovar hardjo is not associated with any substantial proportion of bovine abortions in Victoria, in contrast to the situation in Northern Ireland. The apparent absence from Victoria of the pathogenic genotype Hardjoprajitno is a possible explanation.  相似文献   
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