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71.
This study investigated effects of neglecting genotype × environment (G × E) interaction on the efficiency of index selection, genetic gain and dollar response. Two indices were established. Index P (P for practical) represents an index that would be used in practice. It assumed that no effects of G × E interactions were present. Index T (T for true) accounted for a prevailing level of G × E interactions in a real data set. Since the true underlying genetic parameters of the data set were unknown, different instances of possible G × E interaction levels for Index T were generated through a sampling procedure. The average difference between the genetic correlations used in Index P and T reduced the efficiency of Index P by between 1% and 24.8%. The total dollar response per year was on average 33% overpredicted, but this could be as high as 114%. Larger differences between the correlations resulted in higher variation in efficiency. Larger G × E interactions resulted in larger overpredictions in total dollar response. The effects of not accommodating or assuming the wrong extent of G × E interaction can be considerable in index calculations.  相似文献   
72.
Three dogs with seizures were diagnosed with multiple intracranial meningiomas. Two of the three dogs were golden retrievers, and ages ranged from 9 to 11 years. Treatment consisted of surgery and radiation (n=2) or chemotherapy (n=1). In all three cases, the masses were two distinct tumors as determined by imaging, surgery, or necropsy. In two dogs, the meningiomas had the same histological pattern, while in one dog the histological subtypes were different.  相似文献   
73.
The number of eggs from gastrointestinal nematodes per gram of faeces (worm egg count WEC) is commonly used to determine the need for anti-parasite treatments and the breeding value of animals when selecting for worm resistance. Diarrhoea increases faecal moisture and may dilute the number of worm eggs observed. To quantify this effect, egg counts in sheep at pasture were simulated by dosing 15 animals with chromic oxide particles. The simulated WEC diminished as faecal moisture increased. When faeces were dried, simulated WEC per unit dry matter was not influenced by the amount of faecal moisture present prior to drying. The results suggest that adjustment for faecal moisture may provide an improved estimate of FEC. Drying faeces to calculate the WEC per unit dry matter would provide such an adjustment but may not be practical for industry application. In the past, the CSIRO McMaster Laboratory has used an adjustment factor developed by Gordon based on the classification of faecal consistency derived from the morphology of faeces. To examine the utility of an adjustment factor based on faecal consistency score (FCS), the relationships between FCS and simulated WEC and dry matter were examined. Dry matter and simulated WEC exhibited an exponential decline as FCS increased. The relationship between FCS and dry matter was further examined in 368 samples collected over 12 months from sheep at pasture, where it was observed that dry matter showed a linear decline as FCS increased. Adjustment factors based on dry matter were similar to those proposed by Gordon however adjustment factors predicted from simulated WEC diverged from the remainder for FCS>4. As no samples scored FCS 5 in the study of simulated FEC, the adjustment factors based on the larger study that included samples with FCS 5 was therefore considered more robust. Adjustment factors were given by the equation: WEC(estimated)=(WEC(observed)/(34.21-5.15 FCS))x29.06. This equation estimates for samples with FCS>1 the WEC that would be expected if the samples were FCS 1, the faecal consistency score for normal faeces. The impact of adjustment of observed WEC for faecal moisture predicted by FCS on decision points for treatment and on estimated breeding values requires further examination.  相似文献   
74.
75.
As West Nile virus (WNV) can cause lethal diseases in raptors, a vaccination prophylaxis of free-living and captive populations is desirable. In the absence of vaccines approved for birds, equine vaccines have been used in falcons, but full protection against WNV infection was not achieved. Therefore, two DNA vaccines encoding the ectodomain of the envelope protein of WNV lineages 1 and 2, respectively, were evaluated in 28 large falcons. Four different vaccination protocols were used, including electroporation and booster-injections of recombinant WNV domain III protein, before challenge with the live WNV lineage 1 strain NY99. Drug safety, plasmid shedding and antibody production were monitored during the vaccination period. Serological, virological, histological, immunohistochemical and molecular biological investigations were performed during the challenge trials. Antibody response following vaccination was low overall and lasted for a maximum of three weeks. Plasmid shedding was not detected at any time. Viremia, mortality and levels, but not duration, of oral virus shedding were reduced in all of the groups during the challenge trial compared to the non-vaccinated control group. Likewise, clinical scoring, levels of cloacal virus shedding and viral load in organs were significantly reduced in three vaccination groups. Histopathological findings associated with WNV infections (meningo-encephalitis, myocarditis, and arteritis) were present in all groups, but immunohistochemical detection of the viral antigen was reduced. In conclusion, the vaccines can be used safely in falcons to reduce mortality and clinical signs and to lower the risk of virus transmission due to decreased levels of virus shedding and viremia, but full protection was not achieved in all groups.  相似文献   
76.
77.
Avalanche disturbances are important processes in many subalpine forest ecosystems but have received relatively little research attention in comparison to other major types of disturbances. This paper presents a review of interactions between forests and snow avalanches in mountain ecosystems and discusses how avalanche disturbance regimes and associated management may change in the future. Avalanche disturbance regimes are two-way interactions in which forest structure and composition affect avalanches and avalanches, in turn, affect structure and composition.  相似文献   
78.
In this study, we discuss the consistence of measured and calculated TDR traces. The calculated traces are solutions of a time domain reflectometry (TDR) forward solver, an algorithm for computing the TDR trace for a given dielectric profile along a transmission line. An unambiguous and efficient forward solver is a prerequisite for a good solution of the inverse problem, i.e., to extract the spatial distribution of the dielectric properties along the transmission line from a TDR trace. To advance our understanding of TDR inversion, we proceeded in two steps: (1) design of a TDR head section with minimal disturbances on the signal and (2) searching for causes why measured and predicted TDR traces differ. Based on a first experiment with a three‐rod TDR probe of 100 cm length, we demonstrated that our TDR forward solver—like others presented in literature—approximate the measured TDR traces apparently well but not precisely enough for signal inversion. In a second experiment, using a two‐rod TDR probe of 70 cm length, we addressed the problem of non‐parallel transmission lines. We found that the influence of a non‐parallel installation is similar to an increase of the electrical conductivity in soil water but can be distinguished from this property. A third experiment reveals that lateral and longitudinal disturbances in the vicinity of a TDR probe are of minor importance. From the analysis of our experiments, we found that neither lateral disturbances nor non‐parallel rods are responsible for the deviations between calculated and measured traces. This analysis showed us that structure in the sampled medium affects the shape of the TDR traces. Since minor deviations are essential for TDR‐signal inversion, we need new concepts to handle the fuzziness between measurements and calculations.  相似文献   
79.
Forest soils store large stocks of soil organic matter (SOM) and are of vital importance for the ecosystem supply with nutrients and water. According to the available literature, depending on management regime and site properties, different negative and positive effects of forest management (particularly of forest thinnings and shelterwood cuttings) on soil organic carbon (SOC) and nitrogen (N) stocks are observed. To elucidate the long-term impact of different shelterwood systems and small clear-cuttings on the OC and N stocks of shallow calcareous soils in the Bavarian Alps, we conducted soil humus inventories on different plots of a mixed mountain forest management experiment started in 1976. The silvicultural multi-treatment experiment consists of a NW-exposed Main Experiment (ME) site with eight plots of different cutting intensity (two unthinned controls, two light shelterwood cuttings = 30 % of basal tree area removed, two heavy shelterwood cuttings = 50 % removed, and two clear-cuttings = 100 % removed) on Triassic dolostone. Additionally, plots were installed at a N-exposed dolostone (ND) site and two sites (FL, FH) on Flysch sandstone (each with one unthinned control and one heavy shelterwood cutting). The shelterwood cuttings from 1976 were repeated in 2003 to re-establish the overstorey basal area as produced by the first cutting in the different plots. Thirty-five years after the first treatments, forest floor SOC and N stocks were significantly decreased (up to ?70 %) at the different shelterwood and clear-cut treatments compared to the unthinned control at the ME site despite vigorous development of natural rejuvenation. Also significantly smaller topsoil (forest floor plus mineral soil 0–10 cm depth) OC stocks (between ?16 and ?20 %) were detected at the thinned compared to the control plots. Differences in topsoil N stocks were also considerable (between ?3 and ?14 %), but substantially smaller than OC stock changes. For the total soil down to 30 cm depth, OC stocks in the differently thinned plots were consistently smaller compared to the unthinned control plots. Comparable to our findings at the ME site, heavy shelterwood plots at the three other sites (ND, FL, and FH) showed significant losses of OC in the forest floor (up to 43 %), mineral soil (up to 38 %), topsoil (up to 38 %), and total soil (up to 34 %). Significant large absolute and relative SOC decreases coincided with sites characterized by large initial humus stocks. Moreover, significant effects of heavy shelterwood cuttings on SOC and N stocks (on average 23 % SOC loss and 13 % soil N loss for the forest floor plus the uppermost 10 cm mineral soil) were detected on a regional level. Our results show that different shelterwood systems are accompanied with a considerable long-term decrease in OC and N stocks in shallow calcareous forest soils of the Bavarian Alps. However, a comparison with a windthrown forest stand at a nearby similar site indicates that SOM losses after thinning operations are small compared to decreases following windthrow or other calamities with subsequent large soil erosion and increased mineralization processes.  相似文献   
80.
Many experiments with juvenile trees require the non-destructive monitoring of plant biomass and growth which is most often conducted with allometric relationships between easy to measure morphological traits and plant biomass. In a growth experiment with potted juvenile Fagus sylvatica L. trees, we tested the practicability and accuracy of the portable 3D-laser scanner ZF Imager 5006 using the phase difference method for measuring total above-ground biomass (stems, twigs, leaves), the biomass of axes (stems and twigs), of leaves biomass and the leaf area of 63 experimental trees. The trees were scanned from 20 (or 21) different positions with an angular step width of 0.036° in horizontal and vertical direction and the 3D-point cloud of every tree was translated into a point cloud grid with defined distances between the data points to standardise the spatial resolution of the data. The validation of the laser scan data against traditional biomass harvest data gave good correlations for total above-ground biomass (green and woody plant material combined), leaf biomass and leaf area (obtained by measurements before and after leaf harvest), and the mass of stems and twigs (only woody compartments of the plants) with R2-values between 0.61 and 0.88, all significant with p < 0.001. Biomass estimates using allometric regressions between total plant height or total leaf number and above-ground biomass as alternative non-destructive methods were found to be weaker than laser scanning (R2 0.54-0.67) and required a similar calibration effort. Repeated scanning of the same plant can be used to monitor biomass increase over time. We conclude that 3D-laser scanning is a promising technique for the non-destructive monitoring of biomass and growth in experiments with juvenile trees.  相似文献   
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