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101.
102.
This study was undertaken to examine the potential of the nematode-trapping microfungus Duddingtonia flagrans to survive passage through the gastrointestinal tract of horses and subsequently to destroy free-living stages of cyathostomes in faecal cultures. Three different oral dose levels were tested, two horses being used for each level. Faeces were collected twice daily and the number of parasite eggs per gram of faeces were determined. The numbers of infective third stage larvae which developed in faecal cultures were determined after the cultures had been incubated for 2 weeks at 24°C. Results showed a positive relationship between dose level and reduction in the number of infective larvae. Fungi were recovered in faeces at times which corresponded to high larval reduction.  相似文献   
103.
To evaluate the age of fontanelle closure of normal kittens and the size of their lateral ventricles, 50 ultrasonographic examinations using the bregmatic fontanelle as an acoustic window were made. Seven kittens, laboratory animals, were included in the study. To verify the location of the lateral ventricle, two of the kittens were sacrificed as neonates. In one of them ink was injected prior to autopsy into one lateral ventricle under sonographic guidance. In a longitudinal study of five of the kittens, the skull depth and the depth of the central part of the lateral ventricle reproduced in a longitudinal view could be measured up to the age of about 5 months. During that period, the skull depth increased from a median value of 1.95 cm (1.92-1.98) in a seven-day-old cat to 2.58 cm (2.52-2.59) in a 154-day-old cat, while the afore-mentioned ventricle values increased from 0.3 mm to 1.1 mm.  相似文献   
104.
Is coppice a potential for urban forestry? The social perspective   总被引:1,自引:0,他引:1  
After years of decline and neglect, low woodland types based on coppice management experience renewed interest. Substantial research has demonstrated the potentials of coppice for biomass production and for nature conservation, and coppices are increasingly being suggested for urban situations. Yet, our understanding of the more social aspects of coppice woodlands in modern urban situations is limited. Against this background, this contribution classifies coppice management systems as a basis for identification of social aspects of coppices and their potential use in contemporary urban forestry. Based on this classification, the social perspectives and potential niches for urban coppices are discussed, while lines of research are suggested which will support the development of a thorough and up-to-date knowledge base, against which the social merits of urban coppice woodlands can be critically evaluated.  相似文献   
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107.
The purpose of the study was to investigate the use of hyperspectral imaging (HSI) to detect and quantify chlorophyll (Chl) and total glycoalkaloid concentrations (TGA) in potatoes. To create a set of tubers with different concentrations of Chl and TGA, potatoes of four varieties were wounded or treated with red, blue, red/blue, UV-a, UV-b or UV-c light. HSI analyses were performed with a reflection based setup implemented in an industrial potato sorting machine. After hyperspectral analyses, the peel was sampled, and concentrations of Chl and total TGA were determined. Results showed that the HSI system predicted the concentrations of Chl with a relatively high degree of accuracy, and a prediction R2 value of 0.92. Prediction of TGA concentrations performed to a much lesser extent, and the overall prediction R2 value was only 0.21. Moderate soil covers only affected the prediction powers to a minor degree.  相似文献   
108.
Partial migration is a common phenomenon in many fish species. Trout (Salmo trutta) is a partially migratory species where some part of the population migrate to the marine environment, while another remains in freshwater. In the years 2008 and 2009, a total of 159 wild sea trout smolts were tagged with acoustic and PIT‐tags in the river Villestrup (Denmark) to study the initial postsmolt marine behaviour within a fjord system. We found that the strategies of the sea migrants vary: some stay in the fjord, while others migrate to the sea, suggesting that partial migration occurs even in the marine environments. Overall, a total of 53% of the tagged smolts migrated from the fjord to the sea, and 47% stayed (or potentially died) in the fjord. The ratios of fjord‐resident versus sea‐migrating postsmolts were consistent at the study times, and no differences between the early and late migration periods of the smolts were observed. The individual's size or body condition at the time of tagging did not affect survival or the migratory decisions in the fjord. High overall initial survival (74%) was found 30 days after the fjord entry. We suggest that within a continuum of migration to sea, there is a migratory decision point when sea trout postsmolts encounter a fjord system. At this point, postsmolts will assess the possibility of migration versus the alternative of fjord residency.  相似文献   
109.
Eels (Anguilla spp.) are in decline worldwide, and the signs of reduced recruitment have been observed in continental Europe since the early 1970s. To aid recovery of the European eel, stocking is used by many European countries as a management option. In this study, tagging experiments were conducted to follow eel migration from Lake Mälaren and four sites along the Swedish east coast in the Baltic Sea. The recaptured tagged eels were retrieved from fishermen, allowing for the opportunity to investigate their origin (brackish water, stocked in freshwater or a mix in between) by otolith microchemistry and to assess for morphological differences after tagging. Several changes took place; for example, eye index increased while weight and condition decreased with migrated distance and time until recapture. In Lake Mälaren, the majority of tagged eels did not migrate out of the outlets, irrespective of their origin. Most of them were caught in the opposite direction and continued to be caught in the lake 1–3 years after tagging, with significant weight losses. Overall, overwintering is suggested to be an inferior option, but it is uncertain whether this is a natural behaviour or a result of translocation and restocking. For coastal eels, origin had no effect on migratory behaviour; a majority of the tagged eels migrated towards the outlet of the Baltic Sea. Interestingly, a minority of the recaptured eels originated from stocked fish. Instead, recaptures were dominated by natural immigrants that had spent most of their lives in brackish waters.  相似文献   
110.

The area of short-rotation willow coppice energy plantations on Swedish farmland increased quickly in the early 1990s because of subsidies for energy crop production, an increased CO2 tax on fossil fuel and an already existing biofuel market in the country. In this study farm-related determinants for the adoption of short-rotation willow coppice production among Swedish farmers are identified and estimated. A Tobit model is applied to cross-sectional data on Swedish farmers in 1995. The results show that the decision to plant willow and the areas planted depend positively on arable land area, forest land area, the area of other land types, leasing out of arable land and tractor ownership. Negative factors are pasture area, tenancy and animal production. Differences in willow growing between ownership types, age groups and geographical regions are also important. The policy implications of the results are discussed.  相似文献   
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