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71.
72.
Åke Lindström Juliana Dänhardt Martin Green Raymond H. G. Klaassen Peter Olsson 《Journal of avian biology》2010,41(2):154-162
Today's intensive farming practices are known to have affected farmland biodiversity negatively in many different ways. As far as birds are concerned, they are known to have suffered during both summer and winter. Relatively little is known about the effects on birds during migration. We studied the stopover ecology of the Eurasian golden plover Pluvialis apricaria, a species listed in EU Birds Directive, in intensively farmed arable land in southernmost Sweden in the autumns of 2003–2007. We used key ecological variables (length of stay, fat deposition and moult) as fitness proxies to evaluate how the birds manage in this habitat. Eurasian golden plovers were present in large numbers mainly on arable fields from early August to November and radio‐tagged birds were found to stay in the area for up to three months. Adult birds carried out a substantial part of their flight feather moult during their stay. Body mass increased only somewhat during moult, but from the last stages of moult and onwards fuel loads corresponding to 24% above lean body mass (LBM) were accumulated at a rate of 0.5% of LBM per day, before the birds departed. Juveniles arrived later, from mid Sep., and had a similar pattern of fuel deposition. The fact that the birds choose to stay for long periods, moult in the area, and manage to store substantial fuel loads strongly suggests that Eurasian golden plovers do well in this intensively farmed arable land. 相似文献
73.
Benedicte R. Albrectsen Johanna Witzell Kathryn M. Robinson Sören Wulff Virginia M. C. Luquez Rickard Ågren Stefan Jansson 《Ecography》2010,33(3):483-493
According to the geographic mosaic theory of coevolution (GMTC), clines of traits reflecting local co‐adaptation (including resistance genes) should be common between a host and its parasite and should persist across time. To test the GMTC‐assumption of persistent clinal patterns we compared the natural prevalence of two parasites on aspen Populus tremula trees: mining moths of the genus Phyllocnistis and leaf rust Melampsora spp. Damage data were collated from the Swedish National Forest Damage Inventory (2004–2006). In addition, occurrence of the parasites was scored in field conditions in two common gardens in the north and south of Sweden over five growing seasons (2004–2008), then related to biomass (stem height and diameter) and to concentrations of eleven leaf phenolics. Phyllocnistis mainly occurred in the northern garden, a distribution range which was confirmed by the countrywide inventory, although Phyllocnistis was more abundant on southern clones, providing evidence for possible local maladaptation. Melampsora occurred all over the country and in both gardens, but built up more quickly on northern clones, which suggests a centre of local clone maladaptation in the north. Stem growth also followed a clinal pattern as did the concentration of three phenolic compounds: benzoic acid, catechin and cinnamic acid. However, only benzoic acid was related to parasite presence: negatively to Phyllocnistis and positively to Melampsora and it could thus be a potential trait under selection. In conclusion, clines of Phyllocnistis were stronger and more persistent compared to Melampsora, which showed contrasting clines of varying strength. Our data thus support the assumption of the GMTC model that clines exist in the border between hot and cold spots and that they may be less persistent for parasites with an elevated gene flow, and/or for parasites which cover relatively larger hot spots surrounded by fewer cold spots. 相似文献
74.
Edward G. Robins Yongjun Zhao Imtiaz Khan Anthony Wilson Sajinder K. Luthra Erik Årstad 《Bioorganic & medicinal chemistry letters》2010,20(5):1749-1751
Two S-[18F]fluoroalkylated diarylguanidines were synthesized and evaluated in vitro as potential tracers for imaging of N-methyl-d-aspartate receptors (NMDARs) with positron emission tomography (PET). [18F]1 and [18F]10 were synthesized by [18F]fluoroethylation and [18F]fluoromethylation of the thiol precursor 6, respectively. [18F]1 is a promising candidate NMDAR PET tracer, with low nanomolar affinity for the NMDA PCP-site, high selectivity and moderate lipophilicity. 相似文献
75.
76.
目的:探讨壮骨颗粒对骨折部位新生血管增殖的影响。方法:42只新西兰大白兔,行兔左侧桡骨中段做3mm骨缺损,随机分为壮骨颗粒组,伤科接骨片组,生理盐水组,术后1天开始给药,在第4、6、8周进行X线观察,4w、8w行病理组织学检查。结果:X线片评分半定量分析表明,壮骨颗粒组骨折愈合速度明显快于伤科接骨片组,生理盐水组(P<0.05);I型胶原蛋白免疫组化结果显示壮骨颗粒组I型胶原阳性结果明显比伤科接骨片组、生理盐水组强(P<0.05);壮骨颗粒组血管生成明显多于伤科接骨片组、生理盐水组。结论:壮骨颗粒有明显促进骨痂形成和促进新生血管形成作用。 相似文献
77.
Martin Kellner Agnese Kolodinska Brantestam Inger Åhman Velemir Ninkovic 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(6):1133-1139
Recent studies have shown that volatile chemical interaction between certain barley (Hordeum vulgare) cultivars can cause reduced host plant acceptance by the aphid Rhopalosiphum padi, and that certain cultivars can induce this effect while others can respond. In this study, we tested whether inducing and
responding capabilities are linked to year of release in Swedish two-rowed spring barley. Eighteen cultivars released between
1897 and 1992 were tested in randomly selected subsets with pairwise combinations of volatile emitters and receivers. Significantly
reduced aphid acceptance as a result of exposure to volatiles from plants of a different cultivar were found in 24% of the
cultivar combinations. In general, older cultivars had a higher degree of aphid resistance after barley volatile treatment
than did younger cultivars. The inducing effect of the emitter was also related to date of emitter cultivar release but the
time relationship was reversed. Combinations with a younger volatile emitter and an older volatile receiver gave the strongest
reduction in aphid acceptance of treated plants. Linear relationships between microsatellite diversity of emitting cultivars
and their efficiency as inducers indicated that younger cultivars might have a more unique odour, whereas older cultivars
may be more sensitive to induction. 相似文献
78.
BARBARA ZIMMERMANN PETTER WABAKKEN HÅKAN SAND HANS C. PEDERSEN OLOF LIBERG 《The Journal of wildlife management》2007,71(4):1177-1182
Abstract: To estimate wolf (Canis lupus) kill rates from fine-scale movement patterns, we followed adult wolves in 3 territories of the Scandinavian wolf population using Global Positioning Systems (GPS) during the winters of 2001–2003. The resulting 6 datasets of 62–84 study days gave a total of 8,747 hourly GPS positions. We visited clusters of positions in the field on average 8.8 days after positioning and found moose (Alces alces) killed by wolves during the study period on 74 (8%) of the 953 clusters. The number of positions and visits to a cluster, their interaction, and the proportion of afternoon positions were significant fixed effects in mixed logistic-regression models predicting the probability of a cluster containing a wolf-killed moose. The models, however, displayed a poor goodness-of-fit and were not a suitable tool for estimating kill rates from positioning data alone. They might be used to reduce fieldwork by excluding unlikely clusters, although the reduction was not substantial. We discuss proximate factors (i.e., human disturbance and access to prey) as well as ultimate factors (i.e., social organization, intra-guild dominance, and litter size) as potential causes of the observed high temporal and spatial variation in prey-handling. For similar future kill-rate studies, we recommend increasing field efforts and shortening positioning intervals. 相似文献
79.
PETTER WABAKKEN HÅKAN SAND ILPO KOJOLA BARBARA ZIMMERMANN JON M. ARNEMO HANS C. PEDERSEN OLOF LIBERG 《The Journal of wildlife management》2007,71(5):1631-1634
Abstract: We document a new record dispersal for wolves worldwide. The natal straight-line dispersal distance of a Global Positioning System-collared female wolf from the Scandinavian population was 1,092 km from southeast Norway to northeast Finland, with a multistage actual travel distance of >10,000 km. Natural gene flow to the isolated, inbred Scandinavian wolf population may occur if survival of dispersers is improved. 相似文献
80.
Conserved movement of TMS11 between occluded conformations of LacY and XylE of the major facilitator superfamily suggests a similar hinge‐like mechanism
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The Δ‐distance maps can detect local remodeling that is difficult to accurately determine using superimpositions. Transmembrane segments (TMSs) 11 in both LacY and XylE of the major facilitator superfamily uniquely contribute the greatest amount of mobile surface area in the outward‐occluded state and undergo analogous movements. The intracellular part of TMS11 moves away from the C‐terminal domain and into the substrate cavity during the conformational change from the outward‐occluded to the inward‐occluded state. A difference was noted between LacY and XylE when they assumed the inward open state after releasing a substrate to the inside in which TMS11 of LacY moved further into the substrate release space, whereas in XylE, TMS11 slightly retracted into the C‐terminal domain. Independent movement of the N‐terminal half of TMS11 suggests that it is flexible in the middle. Repeat‐swapped homology modeling was used to discover that a loop connecting TMSs 10 and 11 in LacY probably moves during the transition between the unavailable outward‐open state and the outward‐occluded state. TMSs 11 and the other elements displaying a notable domain‐independent movement colocalize with the interdomain linker, suggesting that these elements could drive the alternating access movement between the domain halves. Preliminary evidence indicates that analogous movements occur in other members of the major facilitator superfamily. Proteins 2015; 83:735–745. © 2015 Wiley Periodicals, Inc. 相似文献