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Intensification of pedestrian tourism causes damage to trees near tourist tracks, and likewise changes the soil structure. As a result, one may expect that annual amount of trees growing near tracks is significantly lower than deeper in the forest. However, during the study of the long-term impact of tourism on the environment (determined from tree increment dynamics), some methodological problems may occur. It is particularly important in protected areas where law and administrative regulations related to nature conservation force research to be conducted using small samples. In this paper we have analyzed the data collected in the Polish part of the Tatra National Park in the two study plots divided into two zones each: the area directly under the influence of the tourist''s trampling and the control group. The aim of such analyses was to present the potential effects of the factors which may affect the results of dendrochronological analysis: (i) small size of samples that affects their representativeness, (ii) spatial differences in the rates of the process, as a result of spatial variability of environmental factors and (iii) temporal differences in the rates of the process. This study confirms that the factors mentioned above could significantly influence the results and should be taken into consideration during the analysis. 相似文献
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T Pawe?czyk 《Acta biochimica Polonica》1999,46(1):91-98
Phospholipase C (PLC, EC 3.1.4.11) is the major starting point in the phosphatidylinositol pathway, which generates intracellular signals that regulate protein kinase C and intracellular calcium concentration. To date, three major types of phosphoinositide-specific PLC species named beta, gamma and delta, have been characterized. This article reviews recent studies on isozymes delta of PLC. Four such isozymes have been cloned and termed delta1-4. Their structural organization, regulation of activity and the interaction with membrane lipid are considered. The intracellular localization of delta isozymes and distribution in various tissues are presented. Attention is given to the pathological conditions in which an abnormal protein level of PLC delta or its activity have been observed. 相似文献
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We used a non-invasive TOBEC method (Total Body Electric Conductivity) to estimate lean body mass and fat content in mouse-eared batsMyotis myotis (Borkhausen, 1797) hibernating in Poznañ Forts (W Poland) and in a semi-natural cave-mine Miedzianka (SE Poland). In December, fat content averaged 5.5 g in females (body mass = 29.4 g) and 5.3 g in males (body mass = 28.4 g). At the end of hibernation (April), fat content averaged 2.2 g in females (body mass = 25.6 g) and 1.4 g in males (body mass = 23.7 g). Fat content did not differ between the localities either in December or in April, but the pattern of changes of fat content was different. We calculated the rate of energy expenditure in hibernating bats using two methods, based on independent samples (fat content in first-time captured individuals) and based on paired observations (changes of fat content in re-captured individuals), and discussed problems associated with the two approaches. Both methods show that the bats need about 4.9 g of fat (191 kJ) to sustain a 165-day hibernation. However, the rate of fat usage varied considerably between the sites and hibernation phase. Although the average amount of fat remaining in April would be sufficient to support at least six more weeks of hibernation, the level of reserves was close to zero in some individuals. 相似文献
1000.
Br. Błocki 《Plant Systematics and Evolution》1884,34(6):212-216
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