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41.
Direct effects of climate change on animal physiology, and indirect impacts from disruption of seasonal synchrony and breakdown of trophic interactions are particularly severe in Arctic and Alpine ecosystems. Unravelling biotic from abiotic drivers, however, remains challenging because high‐resolution animal population data are often limited in space and time. Here, we show that variation in annual horn growth (an indirect proxy for individual performance) of 8043 male Alpine ibex (Capra ibex) over the past four decades is well synchronised among eight disjunct colonies in the eastern Swiss Alps. Elevated March to May temperatures, causing premature melting of Alpine snowcover, earlier plant phenology and subsequent improvement of ibex food resources, fuelled annual horn growth. These results reveal dependency of local trophic interactions on large‐scale climate dynamics, and provide evidence that declining herbivore performance is not a universal response to global warming even for high‐altitude populations that are also harvested.  相似文献   
42.
摘要 目的:本研究旨在探讨对比分析IPS e.max Press铸瓷高嵌体与普兰梅卡CADCAM系统制作的高嵌体修复后牙牙体缺损的效果。方法:以2021年8月-2022年8月我院诊治的60例(86颗)后牙牙体缺损患者为研究对象,采用随机数字表法将其分为研究组(给予普兰梅卡CADCAM系统制作的高嵌体修复)和对照组(给予IPS e.max Press铸瓷高嵌体修复)各30例,对比两组修复前及修复1年后咀嚼功能、牙龈情况、RANK、CXCL16水平、IL-6、IL-8水平,统计修复结果及美牙效果满意度。结果:(1)修复前,两组咀嚼功能比较无差异(P>0.05);修复1年后,研究组咀嚼功能优于对照组(P<0.05);(2)修复前,两组牙龈指数、菌斑指数评分比较无差异(P>0.05);修复1年后,研究组牙龈指数、菌斑指数评分优于对照组(P<0.05);(3)修复前,两组RANK、CXCL16水平比较无差异(P>0.05);修复1年后,研究组RANK、CXCL16水平低于对照组(P<0.05);(4)修复前,两组IL-6、IL-8水平比较无差异(P>0.05);修复1年后,研究组IL-6、IL-8水平与对照组比较(P>0.05);(5)修复1年后,研究组修复体边缘适合性、修复体邻面解剖形态优于对照组(P<0.05);两组修复体表面及边缘着色、修复体折裂与固位比较,差异不显著(P>0.05);(6)修复1年后,研究组美牙效果满意度优于对照组(P<0.05)。结论:与IPS e.max Press铸瓷高嵌体相比,普兰梅卡CADCAM系统制作的高嵌体修复后牙牙体缺损的效果更佳,能够提高咀嚼功能,改善牙龈指数,提高美牙效果满意度。  相似文献   
43.
S. Tang  J. Ou  D. Sun  Y. Zhang  G. Xu  Y. Zhang 《Animal genetics》2011,42(1):108-112
Transforming growth factor‐beta 2 (encoded by TGFB2) is a growth factor that regulates a plethora of cellular functions. In this study, we sequenced the promoter and full‐length exon region of the chicken TGFB2 and found two mutations (g.‐640C>T and g.‐851_‐790del) within the promoter. The two polymorphisms were genotyped in 1030 pedigreed hens recorded for body weight at 7 (BW7), 9 (BW9), 11 (BW11), 13 (BW13), 17 (BW17) weeks old, egg weight at 36 weeks of age (EW36) and egg numbers from the age at first egg (AFE) to 40 weeks of age (EN40). Despite the fact that no mutations were found to have statistically significant genetic effects on egg production, the association results of growth traits showed that both g.‐640C>T and g.‐851_‐790del had significant effects on body weights and that both genotype g.‐640TT and g.‐851_‐790wt/wt were positive for body weight performance. Therefore, the polymorphisms of TGFB2, especially the g.‐851_‐790del mutation associated with body weight at almost all periods, could be potential useful genetic markers to improve the growth of Beijing You chickens.  相似文献   
44.
Mammals adapted to unpredictable and low-energy environments often evolve a “bet-hedging” life history strategy characterized by less costly reproductive outputs over a longer and slower-growing life. In contrast, species adapted to more predictable (i.e., low variation) and higher energy environments may evolve greater fecundity over a shorter and faster-growing life. We tested whether this known interspecific pattern also occurs within a species. We compared life history traits of the ringed seal (Pusa hispida) in the Canadian High Arctic to those closer to the southern limit of the species' circumpolar distribution. We found that northern seals grew slower than southern seals (Brody growth coefficient), achieved a greater asymptotic body weight (82 and 69 kg vs. 74 and 54 kg female and male, respectively), reached sexual maturity later (6.1 years vs. 4.5 years), had lower fecundity (1.8 years vs. 1.3 years interbirth interval), longer average lifespan (5 years vs. 3 years median age), and greater movements (1,269 vs. 681 km). Mating systems also likely differed with northern seals showing morphological evidence of a promiscuous mating system with potential sperm competition as indicated by greater relative testes size. The northern region was also characterized by more unpredictable environmental timing of seasonal events, such as spring sea ice breakup. Life history variation between the intraspecific groups of seals appears to agree with interspecific patterns and provides a better understanding of how species' life history parameters shift in concert with environmental conditions.  相似文献   
45.
Colonies of Penicillium chrysogenum (Thom) Wisconsin strain Q176 were fixed at varying time intervals after having been severed with a razor blade and were examined by transmission electron microscopy. Within such colonies Woronin bodies were found to have plugged septal pores on either side of the cut, both towards and away from the hyphal apices. A very close association of Woronin bodies with septa was retained in damaged compartments emptied of virtually all other contents. In colonies fixed 3 h after cutting, deposition of material over the plugged pores occurred on the side of the septum away from the cut. The newly deposited material was similar in appearance to hyphal wall and septal plate constituents. This consolidation of the seal was apparently completed within 3 h because no further change was observed in colonies fixed 17 h after cutting.  相似文献   
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There is little evidence from nature that divergent natural selection is crucial to speciation. However, divergent selection is implicated if traits conferring adaptation to alternative environments also form the basis of reproductive isolation. We tested the importance of body size differences to premating isolation between two sympatric sticklebacks. The species differ greatly in size, and several lines of evidence indicate that this difference is an adaptation to alternative foraging habitats. Strong assortative mating was evident in laboratory trials, but a few hybridization events occurred. Probability of interspecific mating was strongly correlated with body size: interspecific spawning occurred only between the largest individuals of the smaller species and the smallest individuals of the larger species. Probability of spawning between similar-sized individuals from different species was comparable to spawning rates within species. Disruption of mating between individuals from different species can be traced to increased levels of male aggression and decreased levels of male courtship as size differences increased between paired individuals. Interspecific mate preferences in sympatric sticklebacks appears to be dominated by body size, implicating natural selection in the origin of species.  相似文献   
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中华通草蛉成虫越冬体色变化与滞育的关系   总被引:4,自引:2,他引:4  
对自然条件下中华通草蛉成虫越冬体色变化与滞育关系的系统研究表明,成虫在越冬过程中都经历了一个较明显的体色变化过程,主要表现在体躯底色从绿色到土黄色及体背面滞育斑由褐色到红褐色的改变,据此将成虫体色分成5个级别,在越冬过程中约80%个体体色经历了在生殖型体色(1级)和滞育型体色(4,5级)之间的明显变化,约有20%个体体色维持在2、3级,在越冬前,成虫滞育斑出现后其卵巢不再发育或者发育受抑而逐渐停止发育,滞育斑的出现是成虫开始滞育的重要标志;越冬后,随着成虫体色由滞育型向生殖型的转变,当大多数个体体色变为3级以下时,卵巢开始发育,这些结果说明,中华通草蛉越冬成虫体色的变化是其滞育越冬的一个重要形态指标,越冬前后体色的改变,标志着成虫滞育的开始和结束。  相似文献   
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