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71.
During the latter decades extensive fish kills have been observed in the mountainous areas of southernmost Norway. These kills have been attributed to the increased acidity of the river-water. The increased acidity is generally assumed to be caused by acid precipitation. However, the relationship between precipitation and runoff quality is very complex. The present paper is concerned with the relationship between chemical composition of simulated rain and that of runoff from bare granitic rock, partly covered by lichens. When supplying simulated rain with a pH value of approximately 5 the very first runoff had pH values between 4.1 and 4.3. However, the pH in the runoff increased rapidly and leveled out at values between 4.6 and 4.7. When supplying simulated rain with pH approximately 3.5, the pH in the first runoff varied between 3.8 and 3.6. The pH then gradually decreased to the same values as those in the simulated rain. Runoff from ‘rain’ with pH 4.3, obtained the same pH value as that of the ‘rain’. The pH of the runoff was dependent not only on the rain acidity, but also on its content of neutral salts. 相似文献
72.
There is a lack of research on the benefits and risks of shoeing conditions in harness racing. Thus, our objectives were to: (a) investigate whether velocity times (VT; s/km) are affected by racing unshod (N = 76,932 records on 5,247 horses); (b) determine the potential risks of galloping, being penalized, and disqualification when competing unshod (N = 111,755 records on 6,423 horses); and (c) identify additional environmental factors that affect VT and risks. VT was found to be significantly influenced by shoeing condition (e.g., unshod, shod front, shod hind, or fully shod), but also by sex, age, season, track, track condition, start method, start position, distance, and driver‐horse performance level (p < 2e‐16). The risks of galloping and disqualification were significantly influenced by shoeing condition, sex, age, season, track, start method, start position, or driver‐horse performance level (p ≤ .05). Horses racing unshod had 0.7 s/km lower VT than fully shod horses and showed better performance when racing on neutral tracks during the late summer than horses with other shoeing conditions during the same period. However, racing unshod increased the relative risks of galloping and disqualification by 15%–35% in all seasons. Horses shod only on the hind hooves showed better performance than fully shod horses, without higher risks associated with competing unshod. 相似文献
73.
Analysis of cod catch data from Icelandic groundfish surveys using generalized linear models 总被引:1,自引:0,他引:1
Catch data from the Icelandic groundfish surveys are analyzed using generalized linear models (GLM). The main goal is to test the effects of environmental variables on the expected cod catch and to distinguish between the gamma and log-normal distributions for the error structure. Only positive catch data are included in this work, i.e. only the positive part of a delta–gamma or delta–log-normal distribution is examined. The distributions are compared via a Kolmogorov–Smirnov goodness of fit test. Polynomials are used to describe the relationship between each environmental variable and the cod catch and their effects are tested within the GLM framework (a continuous model). Finally, an attempt is made to locate temperature fronts in the ocean by estimating the temperature gradient vector at each data point. The effect of the size of this gradient vector is then tested within in the GLM framework. A stratification model with only spatial and time effects explains 80% of the variation but that comes with a high cost of degrees of freedom. Most of the tested effects are found to be significant but the continuous model only captures 45% of the total variation. The size of the temperature gradient vector is found to be statistically significant though only a small portion of the variation in the data is explained by this term. 相似文献
74.
75.
This study provides evidence that egg-parasitic nematophagous fungi, Pochonia chlamydosporia, Pochonia rubescens and Lecanicillium lecanii, can also reduce root colonisation and root damage by a fungal pathogen. Interactions of nematophagous fungi with the take-all fungus, Gaeumannomyces graminis var. tritici (Ggt), and their influence on severity of the root disease it causes were studied in laboratory and pot experiments. In Petri dish experiments the three nematophagous fungi reduced colonisation of barley roots by Ggt and also reduced necrotic symptoms. On the contrary, root colonisation by nematophagous fungi was unaffected by Ggt. In growth tube experiments, the three nematophagous fungi again reduced Ggt root colonisation and increased effective root length of barley seedlings. This was true for both simultaneous and sequential inoculation of nematophagous fungi versus Ggt. In the pot experiments the inoculum of the tested fungi in soil was applied in the same pot, as a mixture or in layers, or in coupled pots used for wheat grown with a split-root system. The nematophagous fungi P. chlamydosporia (isolate 4624) and L. lecanii (isolate 4629), mixed with Ggt or in split root systems with the pathogen, promoted growth of wheat (i.e. increased shoot weight), although no disease reduction was found. In split root systems, lower levels of peroxidase activity were found in seedlings inoculated with Ggt in combination with the nematophagous isolates 4624 and 4629 than when the take-all fungus was applied alone.Our results show that nematophagous fungi reduce root colonisation by Ggt, root damage and stress induced senescence in Ggt-inoculated plants. 相似文献
76.
Monica Hansson Nils Lundeheim G?rel Nyman Gunnar Johansson 《Acta veterinaria Scandinavica》2011,53(1):34
Background
Surgical castration in male piglets is painful and methods that reduce this pain are requested. This study evaluated the effect of local anaesthesia and analgesia on vocal, physiological and behavioural responses during and after castration. A second purpose was to evaluate if herdsmen can effectively administer anaesthesia.Methods
Four male piglets in each of 141 litters in five herds were randomly assigned to one of four treatments: castration without local anaesthesia or analgesia (C, controls), analgesia (M, meloxicam), local anaesthesia (L, lidocaine), or both local anaesthesia and analgesia (LM). Lidocaine (L, LM) was injected at least three minutes before castration and meloxicam (M, LM) was injected after castration. During castration, vocalisation was measured and resistance movements judged. Behaviour observations were carried out on the castration day and the following day. The day after castration, castration wounds were ranked, ear and skin temperature was measured, and blood samples were collected for analysis of acute phase protein Serum Amyloid A concentration (SAA). Piglets were weighed on the castration day and at three weeks of age. Sickness treatments and mortality were recorded until three weeks of age.Results
Piglets castrated with lidocaine produced calls with lower intensity (p < 0.001) and less resistance movements (p < 0.001) during castration. Piglets that were given meloxicam displayed less pain-related behaviour (huddled up, spasms, rump-scratching, stiffness and prostrated) on both the castration day (p = 0.06, n.s.) and the following day (p = 0.02). Controls had less swollen wounds compared to piglets assigned to treatments M, L and LM (p < 0.001). The proportion of piglets with high SAA concentration (over threshold values 200, 400 mg/l) was higher (p = 0.005; p = 0.05) for C + L compared to M + LM. Ear temperature was higher (p < 0.01) for controls compared to L and LM. There were no significant treatment effects for skin temperature, weight gain, sickness treatments or mortality.Conclusions
The study concludes that lidocaine reduced pain during castration and that meloxicam reduced pain after castration. The study also concludes that the herdsmen were able to administer local anaesthesia effectively. 相似文献77.
Jörgen Olsson Bengt Gunnar Jonsson Joakim Hjältén Lars Ericson 《Biological conservation》2011,(3):1100-1110
Modern forestry practices have decreased the abundance of coarse woody debris (CWD), and as a result many species that depend on dead wood are now threatened. This implies a need to develop forestry practices that maintain biodiversity. We examined the conservation value of experimental spruce logs (control logs, logs placed in natural shade, and cut tree tops) for wood-inhabiting fungi in two forest stands, one nature reserve and one mature managed forest, in each of seven forest areas in northern Sweden. Here we report the initial findings of the experiment that was established in winter 2001–2002 and data were collected in 2002, 2003 and 2006. A pre-inventory of the local species composition in 2002 revealed a higher per area species richness, including red-listed species, in reserves than in managed forests. Ordination analyses of the experimental logs showed a significant effect of area, while not of stand type in 2003. ANOVA analysis showed no significant effect of stand type on species richness and abundance. In 2006, the species assemblage started to differentiate between the two stand types and forest age, forest site type (moisture), and distance to forest reserves, all explained part of the variation, whereas the amount of CWD, and species composition at the start of the experiment only showed a marginal effect.The early successional fungal community was dominated by two functional groups, humus-decayers and white-rot species, both characterized by a rapid, early colonization and fruit-body formation on the competition-free new substrate. A similar positive response to the new substrate was also observed for the mycorrhizal species in 2006. The high frequency and early appearance of humus-decayers and mycorrhizal species that do not primarily depend upon CWD for their nutrition suggest that their formation of fruiting bodies is limited by substrate availability. Thus some mycorrhizal fungi are apparently rare due to lack of suitable substrate for fruit-body formation.Evidence of dispersal-limitation was observed in 2006. Fomitopsis pinicola, an early colonizer in boreal forests, playing a key role for other wood-inhabiting organisms, colonized significantly more logs in the reserve stands compared with the managed stands. Our data demonstrate that lack of CWD strongly affects both species that depend upon wood for nutrition and species that depend upon wood for fruit-body formation. Thus some species may show an apparent rarity due to lack of suitable substrate. We conclude that creation of CWD appears to be a useful method to maintain or restore fungal diversity in boreal coniferous forests. 相似文献
78.
79.
Daley DO Rapp M Granseth E Melén K Drew D von Heijne G 《Science (New York, N.Y.)》2005,308(5726):1321-1323
The protein complement of cellular membranes is notoriously resistant to standard proteomic analysis and structural studies. As a result, membrane proteomes remain ill-defined. Here, we report a global topology analysis of the Escherichia coli inner membrane proteome. Using C-terminal tagging with the alkaline phosphatase and green fluorescent protein, we established the periplasmic or cytoplasmic locations of the C termini for 601 inner membrane proteins. By constraining a topology prediction algorithm with this data, we derived high-quality topology models for the 601 proteins, providing a firm foundation for future functional studies of this and other membrane proteomes. We also estimated the overexpression potential for 397 green fluorescent protein fusions; the results suggest that a large fraction of all inner membrane proteins can be produced in sufficient quantities for biochemical and structural work. 相似文献
80.
We used Arabidopsis thaliana mutants to examine how a photosynthetic regulatory process, the qE-type or DeltapH-dependent nonphotochemical quenching, hereafter named feedback de-excitation, influences plant fitness in different light environments. We show that the feedback de-excitation is important for plant fitness in the field and in fluctuating light in a controlled environment but that it does not affect plant performance under constant light conditions. Our findings demonstrate that the feedback de-excitation confers a strong fitness advantage under field conditions and suggest that this advantage is due to the increase in plant tolerance to variation in light intensity rather than tolerance to high-intensity light itself. 相似文献