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排序方式: 共有243条查询结果,搜索用时 15 毫秒
101.
Marcin Polak Jarosław Wiącek Marek Kucharczyk Robert Orzechowski 《European Journal of Forest Research》2013,132(5-6):931-941
The very rapid development of the road infrastructure in recent years has adversely affected the natural environment. The main effects of this have been the loss or deteriorating quality of habitats, the mortality of animals due to collisions with road vehicles, the withdrawal of birds as a result of disturbance and excessive noise in the neighbourhood of roads. In this study, we attempted to define the influence of a busy road on a breeding community of woodland birds. Individuals were counted using the point method at 54 observation points located at three various distances (60, 310, 560 m) from the road. At each point, we determined the habitat parameters and the intensity of noise. In total, 995 individuals of 39 species were recorded on the study plot. This study showed that the area was homogeneous with respect to habitat. The number of birds per point increased with distance from the road. Species diversity was lower near the road. The density of nine common species increased with distance from the road. Great Tit Parus major and Song Thrush Turdus philomelos preferred the neighbourhood of the road, whereas the numbers of the other species were the highest in the middle row of points. The number and species diversity of birds were correlated with the pattern of sound propagation across our study area. Our results showed that the species particularly sensitive to road traffic were those nesting near the ground and with low-frequency calls. 相似文献
102.
The study's aim was to analyze the effects of different levels of halloysite (H) and zeolite (Z) in feed and pellets on the growth and meat quality in chickens; 500 Ross 308 broilers were assigned to five groups (1 g, control; 2–5 g, experimental). In Groups 2–5, different proportions of Z and H in feed (25:75 ratio; 0.5% to 2%) and pellet in kg/m2 (2, 0.650H; 3, 0.325H and 0.325Z; 4, 0.650Z; 5, 0.160H and 0.490Z) were used. Body weight was higher than 1 in all experimental groups, and carcass weight was higher, except for Group 2. The feed consumption was lower in Groups 3 and 5 than in Group 4. The breast muscle weight was higher in Group 3 than in the control group. In Groups 2, 3, and 5, the water holding capacity in the breast muscles was better than in Group 4 and in the leg muscles in Groups 3 and 4 than in Groups 1 and 5. Most of the tested characteristics indicate a beneficial effect of aluminosilicates in feed and litter on the growth and quality of meat. 相似文献
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Marek Kolenčík Hana Vojtková Martin Urík Mária Čaplovičová Jaromír Pištora Michael Cada Aneta Babičová Huan Feng Yu Qian Illa Ramakanth 《Water, air, and soil pollution》2017,228(6):224
Artificial adamite [Zn2(AsO4)(OH)] is a convenient structural model because it is isostructural with other rock-forming minerals in secondary ore deposits formed in cementation zones. Microbial activity in these zones accelerates mineral biogeochemical deterioration and metal release, and our results confirmed that Pseudomonas, Rhodococcus and Cupriavidus strains accelerate adamite leaching by 10 to 465 times compared to controls. Here, the Pseudomonas chlororaphis ZK-1 bacterial strain in a static 42-day cultivation proved more effective than Rhodococcus and Cupriavidus by leaching over 90% arsenic and 10% zinc from adamite in one-step in vitro. We evaluated adamite with the VESTA visualization system for electronic and structural analysis, and our results enhance understanding of zinc and arsenic biogeochemical cycles and mobilization, and highlight bacteria’s beneficial natural and biotechnological application in environmental geochemistry and biohydrometallurgy. 相似文献
104.
V. Grosse Liesner V. Taube S. Leonhard‐Marek A. Beineke J. Kamphues 《Journal of animal physiology and animal nutrition》2009,93(3):373-380
The aim of the present study was to investigate the potential effects of different particle fractions in non‐pelleted (meal) and pelleted diets on the development of pre‐ulcerative gastric alterations. Furthermore, the effect of increased crude fibre supply (lignocellulose) on the integrity of gastric mucosa were investigated. For that purpose, 49 piglets were divided into eight feeding groups and fed pelleted diets differing in grinding intensity (very coarse/coarse/fine/very fine) and addition of lignocellulose (0/2.5%) for 6 weeks. A coarsely ground meal was used as control diet. Mucosal integrity of the pars non‐glandularis was characterised by macroscopical and histological score and basal epithelial conductance. Feed structure was assessed by sieve analysis (wet/dry). The use of coarsely ground meal (25% >2 mm, 29% <0.4 mm) had almost no negative effects on the gastric wall: three of seven pigs had slight histological and none had macroscopical lesions. Irrespective of the original grinding intensity before pelleting, offering pelleted diets led to mucosal changes similar in severity (one out of seven pigs fed coarsely ground and pelleted diets had no macroscopical alterations, whereas all pigs fed finely ground and pelleted diets showed altered tissues). Increasing the proportion of coarse particles in the pellet (from 25 to 29% >2 mm) did not show any ulceroprotective effect. An increase of crude fibre content (42–54 g/kg dm) by adding lignocellulose did not result in a decreased ulcerogenity. Unpelleted diets are recommended as more favourable for alleviating the problem of gastric ulcers in pigs as the pelleting process is equal to a secondary grinding process. According to our results, an upper level of fine particles seems to be reasonable (a minimum level of coarse particles is not ulceroprotective). In this study, an amount of 30% <0.4 mm resulted in higher risks for ulcerations. 相似文献
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106.
Aleš Lebeda Michaela Sedlářová Marek Petřivalský Jitka Prokopová 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(1):71-89
Plant pathogenic oomycetes, including biotrophic downy mildews and hemibiotrophs/necrotrophs such as Phytophthora and Pythium, cause enormous economic losses on cultivated crops. Lettuce breeders and growers face the threat of Bremia lactucae, the causal agent of lettuce downy mildew. This pathogen damages leaf tissues and lettuce heads and is also frequent on wild
Asteraceae plants. The interactions of Lactuca spp. with B. lactucae (abbr. lettuce–Bremia) display extreme variability, due to a long co-evolutionary history. For this reason, during the last 30 years, the lettuce–Bremia pathosystem has been used as a model for many studies at the population, individual, organ, tissue, cellular, physiological
and molecular levels, as well as on genetic variability and the genetics of host–parasite interactions. The first part of
this review summarizes recent data on host–parasite specificity, host variability, resistance mechanisms and genetics of lettuce–Bremia interactions. The second part focuses on the development infection structures. Phenotypic expression of infection, behaviour
of B. lactucae on leaf surfaces, the process of penetration, development of primary infection structures, hyphae and haustoria are discussed
in relation to different resistance mechanisms. In the third part, the components of host resistance and the variability of
defence responses are analysed. The role of reactive oxygen species (ROS), antioxidant enzymes, nitric oxide (NO), phenolic
compounds, reorganization of cytoskeleton, electrolyte leakage, membrane damage, cell wall disruption, hypersensitive reaction
and plant energetics are discussed in relation to defence responses. In general, the extreme variability of interactions between
lettuce and Bremia, and their phenotypic expression, results from diversity of the genetic background. Different mechanisms of resistance are
conditioned by an orchestra of defence responses at the tissue, cell, and molecular levels. The various events responsible
for defence involve a complex interaction of the processes and reactions mentioned above. This review also provides an overview
on the timing of pathogen development, host pathological anatomy, cytology and physiology of lettuce–Bremia associations. The significance of these factors on the expression of different resistance mechanisms (non-host and host resistance,
race-specific and race non-specific resistance, field resistance) is discussed. 相似文献
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