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41.
42.

The wire-mesh netting used as the floor material in cages is often claimed to cause walking problems for foxes. The validity of this claim was tested in 96 15-year-old secondary school pupils. They were shown five separate 2 min fragments of videotapes showing the cage pairs with randomized floor material (solid or wire mesh) but with an obstructed view of the floor. The pupils were asked to evaluate the flooring material based on what they actually saw. The mean proportion of correct answers out of 5 for individuals were slightly more than half correct (0.54), but this did not differ significantly from the random value (0.5). When the pairs of foxes had different flooring material, the pupils answered correctly (0.58, P <0.05). Thus, the pupils were not able to identify a specific floor type (wire-mesh or solid floor) but were able to differentiate between two different types of floor based solely on the behaviour of the foxes.  相似文献   
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44.
Thinning intensity and growth of Norway spruce stands in Finland   总被引:4,自引:0,他引:4  
Makinen  Harri; Isomaki  Antti 《Forestry》2004,77(4):349-364
  相似文献   
45.
The aim of this study was to describe the differences in cranial size and shape that occur between different farmed blue fox populations within and between countries. The skulls were obtained at the pelting time from three Finnish, one Estonian, one Norwegian and seven Canadian farms. The material was subjected to a principal component (PC) analysis for each sex. The first PC-factor explained about 50% of variation. It was identified as the size factor; it discriminated Finnish blue foxes at one end and Nova Scotia foxes at the other end of the scale. The second PC-factor explained about 10% of variation in skull morphology but failed to discriminate the populations. The third factor, which was dominated by interorbital width, discriminated Nova Scotia foxes from the other populations. PC-factor 4 received its highest loading from the length of upper tooth row. This factor differentiated, although poorly, the Newfoundland fox populations, whether local or crosses between the local and the imported Finnish stock, from the others. The sexes were significantly different on most single parameters and the skulls of all farm populations were larger than those of wild Arctic foxes. However, there were also large differences in skull morphology between farms within one country. This shows that farmed blue foxes in different countries have not yet diverged into anatomically distinct populations.  相似文献   
46.
Growth, body composition and hair coat parameter variations were evaluated in farmed raccoon dogs (Nyctereutes procyonoides) reared in a conventional two animals -in-cage-system. Daily rate of body weight gain (BWG) of litters very significantly (p less than 0.001) correlated with their time of birth (r = 0.879); the later in spring they were born the faster they gained weight. Final body weight (FBW) of the whelps was to be predicted from their body weight (BW) in early August (r = 0.689). There was no significant correlation between litter size and FBW, BWG or daily rate of BWG. Social competition for food produced great variation in FBW of the animals; the difference between the heavier and lighter raccoon dogs within a cage averaged 1.2 kg (p less than 0.001). Except in FBW and obesity index, there was no significant differences in other parameters between these social groups. Social status within a cage explained only 3.6% of the pelt quality variation while it could explain 52% of the BW variation. Litter explained 36% of the pelt quality, whereas it could explain 4.9% of the BW variation only. Social status and litter did not show any significant two-way interactions. Pelt weight very significantly (p less than 0.001) correlated with pelt quality (r = 0.48) and mass (r = 0.55). Also mass very positively (p less than 0.001) correlated with pelt quality (r = 0.82), indicating that the subjectively estimated pelt quality, in fact, can be derived directly from its weight. We conclude that differences in growth parameters and fur characteristics are mainly produced by social and hereditary factors, respectively.  相似文献   
47.
Downy mildew disease caused by Peronospora sparsa, also known as ‘dryberry’ disease, is a serious threat to the cultivation of arctic bramble (Rubus arcticus) and boysenberry (Rubus spp. hybrid). A quantitative and sensitive screening method is necessary for the breeding of downy mildew resistant cultivars and for determining efficient disease control methods. A quantitative real-time PCR method using SYBR® Green I fluorescent dye was developed for the analysis of P. sparsa in arctic bramble, other Rubus species and roses. Primers were designed to amplify a P. sparsa specific 94-bp fragment from the internal transcribed spacer region (ITS1) and a 140-bp fragment from a conserved region of plant 5.8S ribosomal DNA, which served as an internal control in the samples. Linear amplification from genomic DNA and control plasmids was achieved with both primers, and even 37 fg of P. sparsa conidial DNA was detected. In the samples collected from the field, quantities as low as 0.2 ppm of P. sparsa DNA in plant DNA were detected, thus enabling the diagnosis of weak and latent infections. Arctic bramble cvs Pima, Mespi and Mesma, all showing distinct foliar symptoms, were tested to assess the relative amount of downy mildew DNA present. The symptoms and the amount of P. sparsa DNA detected correlated only in cv. Pima, indicating that visual inspection of symptoms is not a reliable method for assessing the extent of tissue infection. The number of conidiophores of P. sparsa on in vitro inoculated leaves of two arctic bramble cultivars correlated with the results obtained by real-time PCR.  相似文献   
48.
Ecological and aesthetic values in urban forest management   总被引:8,自引:0,他引:8  
In the planning processes of urban forests there are frequent conflicting opinions about the extent to which forests should be managed. On the one hand, management is needed to deal with the intensive use of forests, as well as unfavourable growing conditions, security factors and aesthetic variables. On the other hand, there is an increasing demand for unmanaged areas which is based primarily on ecological arguments. This paper presents research that was conducted in connection with the participatory planning process of Helsinki City forests. The main aim of this research was to study whether aesthetic and ecological values can be combined in the management of urban forests. Furthermore, the stability of forest landscape preferences during the participatory planning process was studied, along with the representativeness of planning groups compared to larger user groups. The data was collected in planning group meetings and public hearings in Helsinki during 1998–2000. Respondents evaluated a set of photographs designed to cover the main conflict situations in urban forest management: Thinnings, understorey management, the leaving of dead snags and decaying ground-wood.

These results show that the majority of residents in Helsinki prefer managed forests. The preferences are, however, closely connected to the background characteristics of respondents. Younger residents with a higher education and active urban forest users prefer more ecologically-oriented management when compared to older residents with less education, or less active users. The individuals had a rather clear and relatively stable opinion of what constitutes suitable management in urban forests, but the views differed considerably as a whole. This means that a participatory planning process will typically lead to some type of compromise. Moreover, the planning groups in Helsinki reflected the opinions of the larger user groups rather well. This indicates that the currently used participatory planning approach sufficiently integrates public values into its planning process.  相似文献   

49.
Three different methods were evaluated for analysing wood formation of Norway spruce [Picea abies (L.) Karst.] and Scots pine (Pinus sylvestris L.) in Finland. During two growing seasons, wood formation dynamics were determined both by wounding the cambium with a needle followed by localisation of the wound-associated tissue modification after the growing season (pinning), and by extracting small increment cores during the growing season (microcoring). Stem radius was additionally monitored with band dendrometers. For Norway spruce, pinning and microcoring yielded similar dates for the onset of wood formation. The timing of wood production during the growing season was also similar for pinning and microcoring. For Scots pine, the onset of wood formation was recorded from microcores almost 2 weeks later than from pinning samples. In Scots pine, microcore measurements also produced somewhat later cessation dates for tracheid formation than the pinning samples. For both tree species, the total number of tracheids formed during the growing season was, however, about the same for pinning and microcoring. Dendrometer results clearly differed from those of pinning and microcoring. In particular, the dendrometers showed an increase of stem radius considerably earlier in spring, when the other methods did not detect wood formation. Thus, pinning and microcoring currently represent the most reliable techniques for detailed monitoring of wood formation.  相似文献   
50.
We present a novel KING breeding design to produce genetically protected homogeneous fish material for commercial producers from a breeding nucleus. KING F2‐production population is established from the nucleus, first through full‐sib mating within two unrelated high‐quality families to produce inbred F1‐progeny and then resolving the inbreeding in F2 through mating of the unrelated F1‐individuals. Owing to a small number of founders and the inbred F1‐parents, the remaining additive genetic variance is 37.5% of the original. This restricts the use of F2‐progeny to establish new breeding programmes, thereby protecting the genetic material of the nucleus. The theoretical calculations show that a concomitant decrease of phenotypic variance is possible. However, the reduction is considerable only for traits with high heritability (h2 > 0.50). The method was tested with rainbow trout. The results revealed that the mean body weight of the KING‐progeny was similar, but, surprisingly, phenotypic variation (especially due to residual variance) was higher compared with either their outbred control group or the nucleus breeding population. Although further evaluation of this breeding design is needed, the results suggest that while genetic protection is achieved, the efficiency of the method to reduce phenotypic variation is limited for economically important traits with low‐to‐moderate heritability.  相似文献   
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