Measuring tree-ring increments on tree bole sections with a video-based robotic positioner

We report on the design and performance of a system that speeds measurement of radial tree-ring increments on tree stem disks; this method replaces the usual binocular microscope with a video image, and automates the measuring and recording processes. The system was used to measure bole sections cut from stems at various heights to determine volume growth of representative trees in an old-growth ponderosa pine stand. The objective of the measurement system was to speed acquisition of annual growth increments from a large number of disks. A personal computer controls the location of a video camera in a 3-axis positioning system. The operator views the sample on a video monitor and positions the camera over each ring by selecting it with a computer-driven mouse. The computer measures and records the distance that the camera moves between each ring. Task selection is facilitated by menu-driven software that also formats, checks and organizes data files. Measurements have a resolution of 0.026 mm; however, finer resolution could be obtained with a different camera lens. Tests of measurement variability (repeated measurements by individual operators on a single radius) indicated standard errors of 0.006 mm or less for the first measurement sets for four operators. Correlation coefficients among four radii per bole section were as low as 0.66 for a whole tree, suggesting that measurements on single radii may provide poor estimates of radial growth for old trees. This system also offers the potential for automatic ring detection and measurement.     

Straelensiosis in two cats and ten dogs from Israel

Straelensiosis is uncommonly described outside Europe. This report describes straelensiosis in two cats and in ten dogs diagnosed with the disease outside Europe. Both cats displayed erythematous macules or nodules on the abdominal skin. One cat was extremely pruritic, while in the other the lesions were incidental findings when the cat was presented for neutering. The mites were noted in skin scrapings in both cats and histopathologically in one cat. All dogs showed a general distribution of papules, and intense pruritus was noted in six dogs. The diagnosis in all dogs was based on histopathology. Treatment of the animals in this study varied, and among the various administrated treatments, amitraz showed promising results.     

Heifer breeding farms as a source for spreading the BVD virus?

It is well known that, in Switzerland, communal grazing of livestock on alpine pastures plays an important role in the spread of BVD virus. Analogously, we might expect that the communal raising on farms specialising in raising heifers of animals born on different farms would also favour the spread of BVDV. This study investigated whether a persistently infected (PI) breeding heifer kept on this type of farm over a period of 26 months would put the other animals at risk of being infected.The PI-animal was in contact with 75 heifers (here defined as contact animals) on this farm. Thirty-two of the contact animals that were probably pregnant (animals at risk of giving birth to a PI-calf) were moved to 8 different breeding farms (here defined as farms at risk). On these 8 farms, 246 calves were found to be at risk of being infected with BVDV. We examined 78 calves and investigated whether the move of the pregnant animals from their original farm had permitted the virus to spread to these 8 other farms.The contact animals had a seroprevalence of 92% and the animals at risk a seroprevalence of 100%. Only one PI-animal was found on the farms at risk.This BVD infection, however, occurred independently of the PI-breeding animal. Seropositive calves were found only on 2 farms. This study did not provide any proof for a spread of BVDV with the PI-breeding animal as a source; likewise, no persistent infection was proven to exist on the farms at risk. This result is likely to be representative for the endemic situation of BVD in Switzerland. Thus, PI-animals present on heifer raising farms infect calves well before servicing. Hence, no new PI-animals are generated, and the infection becomes self-limiting. When we reconstructed the animal movements between the farms and determined the animals to be examined with the aid of the Swiss national animal traffic database (TVD) we found the data of 37% of the heifers to be incomplete and failed to successfully establish the whereabouts of 3 animals.     

Further analysis of anti-human leukocyte mAbs with reactivity to equine leukocytes by two-colour flow cytometry and immunohistochemistry

We have reported on the reactivity of anti-human CD molecules with equine leukocytes by single-colour flow cytometry (this issue). The objectives of this additional study were to test for the reliability of the results obtained, and to obtain further information on the positive populations of lymphocytes. Two-colour flow cytometry and immunohistochemistry were performed, using many of the positive mAbs and a few questionable ones from the first part of the study. All mAbs analysed by two-colour flow cytometry could be confirmed to their previous designation as "positive" or "questionable". Most of the mAbs tested were effective in immunohistochemistry, supporting previous results. Examples of positive results will be presented and limitations of the study will be discussed briefly.     

接种丛枝菌根菌对盆栽孔雀草生长的影响

在盆栽孔雀草上接种两种丛枝菌根真菌(Glomus mosseae 和Glomus versiforme).在两个月的试验期内,前40 d两种处理在株高、茎粗、主叶片数上都表现出显著的促进宿主植物营养生长的作用,在单株花蕾数上表现出延缓生殖生长的作用;后20 d两种处理在茎粗方面以及处理G. versiforme在株高上仍然表现出显著的促进宿主植物营养生长的作用,而两种处理在单株花蕾数上表现出促进生殖生长的作用,但对花冠直径没有影响.     

Genetic parameters for individual birth and weaning weight and for litter size of Large White pigs

Data from a French experimental herd recorded between 1990 and 1997 were used to estimate genetic parameters for individual birth and weaning weight, as well as litter size of Large White pigs using restricted maximum likelihood (REML) methodology applied to a multivariate animal model. In addition to fixed effects the model included random common environment of litter, direct and maternal additive genetic effects. The data consisted of 1928 litters including individual weight observations from 18151 animals for birth weight and from 15360 animals for weaning weight with 5% of animals transferred to a nurse. Estimates of direct and maternal heritability and proportion of the common environmental variance for birth weight were 0.02, 0.21 and 0.11, respectively. The corresponding values for weaning weight were 0.08, 0.16 and 0.23 and for litter size 0.22, 0.02 and 0.06, respectively. The direct and the maternal genetic correlations between birth and weaning weight were positive (0.59 and 0.76). Weak positive (negative) genetic correlations between direct effects on weight traits and maternal effects on birth weight (weaning weight) were found. Negative correlations were found between direct genetic effect for litter size and maternal genetic effects on all three traits. The negative relationship between litter size and individual weight requires a combined selection for litter size and weight.     

Long-term,landscape patterns of past fire events in a montane ponderosa pine forest of central Colorado

Parameters of fire regimes, including fire frequency, spatial extent of burned areas, fire severity, and season of fire occurrence, influence vegetation patterns over multiple scales. In this study, centuries-long patterns of fire events in a montane ponderosa pine – Douglas-fir forest landscape surrounding Cheesman Lake in central Colorado were reconstructed from fire-scarred trees and inferences from forest stand ages. We crossdated 153 fire-scarred trees from an approximately 4000 ha study area that recorded 77 total fire years from 1197 to the present. Spatial extent of burned areas during fire years varied from the scale of single trees or small clusters of trees to fires that burned across the entire landscape. Intervals between fire years varied from 1 to 29 years across the entire landscape to 3 to 58 years in one stand, to over 100 years in other stands. Large portions of the landscape did not record any fire for a 128 year-long period from 1723 to 1851. Fire severity varied from low-intensity surface fires to large-scale, stand-destroying fires, especially during the 1851 fire year but also possibly during other years. Fires occurred throughout tree growing seasons and both before and after growing seasons. These results suggest that the fire regime has varied considerably across the study area during the past several centuries. Since fires influence plant establishment and mortality on the landscape, these results further suggest that vegetation patterns changed at multiple scales during this period. The fire history from Cheesman Lake documents a greater range in fire behavior in ponderosa pine forests than generally has been found in previous studies.     

Die Bekämpfung der Rübenfliege (Pegomyia hyoscyami Pz.)mit Fluornatrium und Kieselfluornatrium

Ohne Zusammenfassung (Ref.) aus der Biologischen Reichsanstalt für Land- und Forstwirtschaft.