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31.
Neospora caninum is a parasite responsible for paresis in dogs. The dog can harbour enkysted parasites in several organs. The detection of N. caninum was performed using 3 different real time PCR systems all amplifying the NC5 DNA region. One system was based on Sybrgreen, one on Plexor technology and the last on Taqman probe. Comparison of the three methods indicated that the detection limit was 1 equivalent genome on pure DNA but that this detection limit increased in the presence of foreign DNA using the Sybrgreen and Plexor systems. Therefore, the Taqman system was chosen to detect N. caninum in liver and spleen of naturally infected dogs. The overall prevalence was 32.2%. Comparison between PCR results and serological results using IFAT showed that among the 28 PCR positive dogs only 9 were seropositive and that 8 seropositive dogs were PCR negative. Therefore serology can underestimate the real carriage in dogs. However, PCR methods must be improved in terms of sensitivity and inhibition problems. 相似文献
32.
Spangler ML Sapp RL Bertrand JK MacNeil MD Rekaya R 《Journal of animal science》2008,86(10):2471-2479
It is possible to predict genotypes of some individuals based on genotypes of relatives. Different methods of sampling individuals to be genotyped from populations were evaluated using simulation. Simulated pedigrees included 5,000 animals and were assigned genotypes based on assumed allelic frequencies for a SNP (favorable/unfavorable) of 0.3/0.7, 0.5/0.5, and 0.8/0.2. A field data pedigree (29,101 animals) and a research pedigree (8,688 animals) were used to test selected methods using simulated genotypes with allelic frequencies of 0.3/0.7 and 0.5/0.5. For the simulated pedigrees, known and unknown allelic frequencies were assumed. The methods used included random sampling, selection of males, and selection of both sexes based on the diagonal element of the inverse of the relationship matrix (A(-1)) and absorption of either the A or A(-1) matrix. For random sampling, scenarios included selection of 5 and 15% of the animals, and all other methods presented concentrated on the selection of 5% of the animals for genotyping. The methods were evaluated based on the percentage of alleles correctly assigned after peeling (AK(P)), the probability of assigning true alleles (AK(G)), and the average probability of correctly assigning the true genotype. As expected, random sampling was the least desirable method. The most desirable method in the simulated pedigrees was selecting both males and females based on their diagonal element of A(-1). Increases in AK(P) and AK(G) ranged from 26.58 to 29.11% and 2.76 to 6.08%, respectively, when males and females (equal to 5% of all animals) were selected based on their diagonal element of A(-1) compared with selecting 15% of the animals at random. In the case of a real beef cattle pedigree, selection of males only or males and females yielded similar results and both selection methods were superior to random selection. 相似文献
33.
The objective of this study was to determine the suitability of 2 methods for computing approximate accuracies of predicted breeding values, in which accuracy was defined as the squared correlation between the predicted and true breeding value, when modeling growth traits in beef cattle using random regression (RR) models. The first method (Strabel et al., S-M-B) was designed for use with multitrait models; thus, its use with RR models requires the clustering of measurements into different traits. The second method (Tier and Meyer, T-M) was more general, because it accounted for random coefficients other than zeros and ones and thus it could be used directly when fitting RR models. To investigate the performance of both methods, their results were compared with the true accuracies using a balanced simulated data set. The largest difference between approximate and true average accuracies for direct effects was observed at 205 d when S-M-B was used (4.6% males and 8.8% females). With regard to maternal effects, the largest differences in average accuracies were observed at 205 d in males when S-M-B was used (31.8%) and at the same age in females but when using T-M (33.3%). In general, bias increased for direct effect accuracies in males at the tails of the accuracy range, but for females and for maternal effect accuracies in both sexes, bias increased as accuracy increased. When a population was simulated to create large numbers of progeny for base females that did not have individual records, much greater errors were observed in the regression of approximate values on the true ones. When both approximate methods were compared using a real beef cattle data set, a good agreement was observed, particularly for direct effect accuracies in sires [i.e., at 205 d, the regressions were 0.98 (direct) and 0.95 (maternal) with r(2) over 0.99]. The largest discrepancies for sires between the methods were observed at 205 d for direct (2.7%) and maternal (16.3%) effect accuracies. For dams, the largest differences between methods were also observed at 205 d, 9.3% (direct), and 15.2% (maternal). The differences between methods for nonparent cattle were greater than for dams for maternal effect accuracies but intermediate between sires and dams for direct effect accuracies. In spite of the less biased results provided by T-M, its use could be problematic when employed in evaluations of large populations due to its greater memory and computation requirements (e.g., 170 and 478% more than S-M-B for a population of 11 million). 相似文献
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35.
In the durum wheat industry, the milling process leads to the production of different fractions such as semolina, flours, bran and thirds. The histological origin and composition of these fractions are not easy to determine. Moreover, the proportions of kernel tissue in a given fraction depend on the wheat cultivar. In the present work, 4 batches of durum wheat were processed in an experimental semolina pilot plant leading to the extraction of 18 representative fractions. Multispectral images of both the final fractions and wheat kernels have been acquired with an in-house imaging system. By performing principal component analysis and a Kmeans procedure on the multispectral images of each fraction, a reference spectral fingerprint was assessed for every fraction. For each pixel of the images of kernel cross-section, it was possible to calculate its probability of belonging to a typical group of fingerprint, and then to build up a probability image. These probability images, presented in false colors, emphasized the areas in the kernels from which a given milled fraction was extracted. The images obtained in this way enable a more precise identification of the histological origin of the different milled fractions. 相似文献
36.
Marie Charru Ingrid Seynave Jean-Christophe Hervé Romain Bertrand Jean-Daniel Bontemps 《Annals of Forest Science》2017,74(2):33
Key message
Recent growth changes (1980–2007) in Western European forests strongly vary across tree species, and range from +42% in mountain contexts to ?17% in Mediterranean contexts. These changes reveal recent climate warming footprint and are structured by species' temperature (?) and precipitation (+) growing conditions.Context
Unprecedented climate warming impacts forests extensively, questioning the respective roles of climatic habitats and tree species in forest growth responses. National forest inventories ensure a repeated and spatially systematic monitoring of forests and form a unique contributing data source.Aims
A primary aim of this paper was to estimate recent growth changes in eight major European tree species, in natural contexts ranging from mountain to Mediterranean. A second aim was to explore their association with species’ climatic habitat and contemporary climate change.Methods
Using >315,000 tree increments measured in >25,000 NFI plots, temporal changes in stand basal area increment (BAI) were modelled. Indicators of climate normals and of recent climatic change were correlated to species BAI changes.Results
BAI changes spanned from ?17 to +42% over 1980–2007 across species. BAI strongly increased for mountain species, showed moderate/no increase for generalist and temperate lowland species and declined for Mediterranean species. BAI changes were greater in colder/wetter contexts than in warmer/drier ones where declines were observed. This suggested a role for climate warming, further found more intense in colder contexts and strongly correlated with species BAI changes.Conclusion
The predominant role of climate warming and species climatic habitat in recent growth changes is highlighted in Western Europe. Concern is raised for Mediterranean species, showing growth decreases in a warmer climate with stable precipitation.37.
Christoforos Karanikas Vincent Walker Apostolos Scaltsoyiannes Gilles Comte Cédric Bertrand 《Annals of Forest Science》2010,67(4):412-412
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39.
Bernard Tivoli Agnès Calonnec Benjamin Richard Bertrand Ney Didier Andrivon 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(3):471-478
To reduce the use of pesticides, innovative studies have been developed to introduce the plant as the centre of the crop protection system. The aim of this paper is to explain how architectural traits of plants and canopies induce a more or less severe epidemic and how they may be modified in order to reduce disease development. In particular, it focuses on three key questions: i) which processes linked to epidemics can be influenced by architecture ii) how can architecture be characterized relative to these modes of action, and iii) how can these effects be explored and exploited? The roles of plant/canopy architecture on inoculum interception, on epidemic development via the microclimate and on tissue receptivity are discussed. In addition, the concepts of disease avoidance, canopy porosity and an ideotype unfavourable for disease development are described. This paper shows that many advances have already been made, but progress is still required in four main fields: microclimatology, mathematical modelling of plants, molecular genetics and ideotype conception. 相似文献
40.
Muhammad Shahid Camille Dumat Bertrand Pourrut Jérôme Silvestre Christophe Laplanche Eric Pinelli 《Journal of Soils and Sediments》2014,14(4):835-843