The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warble...The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warbler (Acrocephalus scirpaceus) host nests. However, social information alerts hosts to see through the cuckoo’s mimetic disguise. In turn, this has promoted the evolution of a cuckoo polymorphism to thwart host recognition. Here we show by comparative analyses that parasitic cuckoos with hawk-like features (yellow eyes, barred underparts, yellow legs) are more likely to be polymorphic (29% of species) than those without (8% of species). Phylogenetic analyses confirm correlated evolution of hawk-like features and cuckoo polymorphism. We suggest that mimicry dynamics are particularly likely to promote the evolution of various guises in parasitic cuckoos to beat host defences.展开更多
Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plant...Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plants, was demonstrated by nested polymerase chain reaction assay employing phytoplasma universal rRNA primer pairs-P1/P7 followed by R16F2n/R16R2. Products of PCR primed by R 16F2n/R 16R2 primer pair from naturally infected Brussels sprouts were sequenced. Comparison of the obtained 16S rDNAs revealed high nucleotide sequence identity between analyzed phytoplasma isolates （99.8%-100%）. They were also nearly identical with the sequences of other phytoplasmas isolates from sub-group 16SrI-B, and they were classified as members of ＂Candidatus Phytoplasma asteris＂.展开更多
An asymptotic semi-analytical method for heat transfer in counter-flow honeycomb regenerator is proposed. By introducing a combined heat-transfer coefficient between the gas and solid phase, a heat transfer model is b...An asymptotic semi-analytical method for heat transfer in counter-flow honeycomb regenerator is proposed. By introducing a combined heat-transfer coefficient between the gas and solid phase, a heat transfer model is built based on the thin-walled assumption. The dimensionless thermal equation is deduced by considering solid heat conduction along the passage length. The asymptotic analysis is used for the small parameter of heat conduction term in equation. The first order asymptotic solution to temperature distribution under weak solid heat conduction is achieved after Laplace transformation through the multiple scales method and the symbolic manipulation function in MATLAB. Semi-analytical solutions agree with tests and finite-difference numerical results. It is proved possible for the asymptotic analysis to improve the effectiveness, economics and precision of thermal research on regenerator.展开更多
利尿剂联合血管紧张素转换酶抑制剂(ACEI)或血管紧张素受体拮抗剂(ARB)加用非甾体类抗炎药物(NSAID)是否增加急性肾损伤风险值得探讨。该研究采用回顾性队列研究,进行巢式病例对照分析。使用与英国临床实践研究数据链(UK clinical pract...利尿剂联合血管紧张素转换酶抑制剂(ACEI)或血管紧张素受体拮抗剂(ARB)加用非甾体类抗炎药物(NSAID)是否增加急性肾损伤风险值得探讨。该研究采用回顾性队列研究,进行巢式病例对照分析。使用与英国临床实践研究数据链(UK clinical practice research datalink)相关联的统计数据(hospital episodes statistics data-base),评估利尿剂或ACEI或ARB中的一种联合使用NSAID(二联用药)和利尿剂联合ACEI或ARB中的一种加用NSAID(三联用药)与急性肾损伤风险的相关性。研究共纳入使用降压药的患者487372例,经过(5.9±3.4)年随访,确诊急性肾损伤2215例(发病率7/10000人年)。研究结果显示,二联用药与急性肾损伤无关,而三联用药与急性肾损伤相关(RR1.31,95%CI1.12～1.53),进一步研究分析,在最开始治疗的30天内,三联用药与急性肾损伤风险的相关性最高(RR1.82,95%CI1.35～2.46)。结论:利尿剂联合ACEI或ARB中的一种加用NSAID(三联用药)与急性肾损伤相关。展开更多
The narG gene is frequently used as a molecular marker for bacterial nitrate-reducing community analysis. In this study, a new set of primers targeting the narG gene was designed and applied to semi-nested polymerase ...The narG gene is frequently used as a molecular marker for bacterial nitrate-reducing community analysis. In this study, a new set of primers targeting the narG gene was designed and applied to semi-nested polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） assay. The potential of the new primers was verified on DNA directly extracted from soils from five different experimental sites distributed in Central and Southern Italy. Specificity of the primers was determined by excision, amplification, and sequencing of bands resolved by DGGE. A phylogenetic analysis showed the correlation between the sequences retrieved from the soils studied and the narG sequences from βand y-Proteobacteria. These primers expanded the existing molecular tools for ecological study on the size and diversity of nitrate-reducing bacterial community in soil.展开更多
基金funded by the Natural Environment Research Council
文摘The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warbler (Acrocephalus scirpaceus) host nests. However, social information alerts hosts to see through the cuckoo’s mimetic disguise. In turn, this has promoted the evolution of a cuckoo polymorphism to thwart host recognition. Here we show by comparative analyses that parasitic cuckoos with hawk-like features (yellow eyes, barred underparts, yellow legs) are more likely to be polymorphic (29% of species) than those without (8% of species). Phylogenetic analyses confirm correlated evolution of hawk-like features and cuckoo polymorphism. We suggest that mimicry dynamics are particularly likely to promote the evolution of various guises in parasitic cuckoos to beat host defences.
文摘Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plants, was demonstrated by nested polymerase chain reaction assay employing phytoplasma universal rRNA primer pairs-P1/P7 followed by R16F2n/R16R2. Products of PCR primed by R 16F2n/R 16R2 primer pair from naturally infected Brussels sprouts were sequenced. Comparison of the obtained 16S rDNAs revealed high nucleotide sequence identity between analyzed phytoplasma isolates （99.8%-100%）. They were also nearly identical with the sequences of other phytoplasmas isolates from sub-group 16SrI-B, and they were classified as members of ＂Candidatus Phytoplasma asteris＂.
基金Supported by Chinese National Programs for High Technology Research and Development (No. 2001AA514013)
文摘An asymptotic semi-analytical method for heat transfer in counter-flow honeycomb regenerator is proposed. By introducing a combined heat-transfer coefficient between the gas and solid phase, a heat transfer model is built based on the thin-walled assumption. The dimensionless thermal equation is deduced by considering solid heat conduction along the passage length. The asymptotic analysis is used for the small parameter of heat conduction term in equation. The first order asymptotic solution to temperature distribution under weak solid heat conduction is achieved after Laplace transformation through the multiple scales method and the symbolic manipulation function in MATLAB. Semi-analytical solutions agree with tests and finite-difference numerical results. It is proved possible for the asymptotic analysis to improve the effectiveness, economics and precision of thermal research on regenerator.
文摘利尿剂联合血管紧张素转换酶抑制剂(ACEI)或血管紧张素受体拮抗剂(ARB)加用非甾体类抗炎药物(NSAID)是否增加急性肾损伤风险值得探讨。该研究采用回顾性队列研究,进行巢式病例对照分析。使用与英国临床实践研究数据链(UK clinical practice research datalink)相关联的统计数据(hospital episodes statistics data-base),评估利尿剂或ACEI或ARB中的一种联合使用NSAID(二联用药)和利尿剂联合ACEI或ARB中的一种加用NSAID(三联用药)与急性肾损伤风险的相关性。研究共纳入使用降压药的患者487372例,经过(5.9±3.4)年随访,确诊急性肾损伤2215例(发病率7/10000人年)。研究结果显示,二联用药与急性肾损伤无关,而三联用药与急性肾损伤相关(RR1.31,95%CI1.12～1.53),进一步研究分析,在最开始治疗的30天内,三联用药与急性肾损伤风险的相关性最高(RR1.82,95%CI1.35～2.46)。结论:利尿剂联合ACEI或ARB中的一种加用NSAID(三联用药)与急性肾损伤相关。
基金Supported by the Integrated Special Fund for Research (FISR), Italy
文摘The narG gene is frequently used as a molecular marker for bacterial nitrate-reducing community analysis. In this study, a new set of primers targeting the narG gene was designed and applied to semi-nested polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） assay. The potential of the new primers was verified on DNA directly extracted from soils from five different experimental sites distributed in Central and Southern Italy. Specificity of the primers was determined by excision, amplification, and sequencing of bands resolved by DGGE. A phylogenetic analysis showed the correlation between the sequences retrieved from the soils studied and the narG sequences from βand y-Proteobacteria. These primers expanded the existing molecular tools for ecological study on the size and diversity of nitrate-reducing bacterial community in soil.
