基于人工神经网络的多处损伤加筋板剩余强度预测

用BP神经网络算法对多处损伤加筋板的剩余强度数据进行训练学习,将预测值和3种经典分析方法的计算值与实验值进行对比,结果表明,ANN法预测值与实验值吻合得最好,LMC修正法和WSU3修正法次之,Swift塑性区连通法最差。最后用所建立的BP网络对不同主裂纹半长和韧带长度的剩余强度进行了预测,结果发现,在其他参数不变的情况下,不管是双筋条还是三筋条加筋板,剩余强度总是随主裂纹半长的增加而成线性降低,随韧带长度的增加而成线性增加,但双筋条加筋板比三筋条加筋板对主裂纹半长和韧带长度的变化更加敏感。     

Reproductive strategies used by moorhens (Gallinula chloropus) colonizing an artificial wetland habitat in south Wales

Over the last ten years, a high-density breeding population (c.180 individuals) of moorhens Gallinula chloropus (Linnaeus) has become established in an artificially created wetland habitat at the Wildfowl and Wetlands Trust (WWT) centre in Llanelli. The reproductive behaviour and success of this population was the subject of an intensive study between 1997–1999. Whilst monogamy was the dominant breeding system used at the site, some individuals bred annually in communal and co-operative groups. The majority of individuals within communal and co-operative groups in 1998 and 1999 were first order relatives. The number of communal groups recorded progressively declined whereas the number of co-operative groups increased over the period of study. Territory size of breeding groups was unrelated to either breeder type or group number. Most nests were constructed in Juncus although many birds also nested in trees and nest boxes intended for captive bred wildfowl. Vegetation height above nests strongly influenced breeding success, and nest site choice at the site was partially determined by vegetation management practices. Such practices may have been responsible for decreased nesting success in specific areas. Rats were the principal egg predators on site accounting for approximately 80% of eggs predated. The study reveals how the reproductive dynamics of this opportunistic bird influences its successful colonization of a new habitat.     

抗生素Bagremycin生产菌Streptomyces sp. Tü4128接合转移系统的建立

基于噬菌体φC31 att/int系统,采用属间接合将来自大肠杆菌的DNA有效地导入菌株Tü4128的孢子中。通过条件优化,当融合温度为37℃时,在含80mmol/L MgCl2的ISP4培养基上使每个受体细胞的接合频率显著提高到7.3×10-3。Southern blot分析显示在受体菌染色体上存在单一的染色体附着位点(attB位点)。整合位点的DNA序列测序显示为保守。采用优化的方法建立了大肠杆菌和菌株Tü4128间高效的属间接合系统。     

遥感和CA在城市医院选址中的应用

城市医院的选址是一个相当复杂的过程，要考虑很多因素。本文运用遥感技术，基于元胞自动机的原理，提出了用算法根据交通流量最优转换规则来进行城市医院选址的布局，实现较合理的基于定量化的医院选址。     

伏牛山文化圈史前城址与中国文明起源探索——伏牛山文化圈与中国文明起源探索之二

伏牛山文化圈在旧石器时代已经有人类居住与生产。近一个世纪的考古发现证明，伏牛山文化圈史前城址遗存非常丰富，是中国史前城址的发源地之一。伏牛山文化圈史前城址演进的脉络完整清晰：城址性质由仰韶文化的初城开始，逐渐演进为龙山文化的城址群，二里头文化的宫城，并与殷商成熟都城相衔接。伏牛山文化圈是中国文明的发源地之一。     

浅谈水利工程施工现场的管理

阐述了水利工程施工现场管理常出现的几个问题,提出相应的解决措施。     

浅谈安全管理与现场安全控制

详细论述了安全的定义、海恩法则、安全管理控制的因素、施工安全管理控制的要点等,以期进一步加强人们的安全意识。     

Splicing signals in the human hemoglobin genes at the sequence and folding levels

Identification of the splice sites is a critical and tough issue in eukaryotic genome annotation. Here, a statistical study is introduced for detecting the splicing signals in the human hemoglobin (Hb) pre-mRNAs by using the approaches of regional pairwise alignment, splicing weight matrix scoring, and dynamic extended folding. First, the regional pairwise alignment results show that the coding regions of the human Hb genes are at a high level for both conservation and fluctuation. Second, the weighted matrix scoring results indicate that, although the authentic splicing motifs are always scored the highest in a sequence, the sequence motif alone is inadequate to precisely define the splice sites. Finally, we deduce the RNA frame structures by applying an extended folding approach to analyze the stable folding elements. We find out that the splice sequences tend to take stretching and partially paired conformations, which benefit recognition and competitive binding of the splicing factors. These results indicate that precise splicing is an integrated effect of multiple mechanisms of signal recognition at the level of sequence and structure.     

湖北长阳香炉石遗址夏代遗存分析

文章系统分析了香炉石遗址第7层遗存,将其与石板巷子遗存和三峡地区的白庙文化进行了比较,认为三者间存在密切的关联,但还不能归入这两类遗存中的任何一类。将香炉石遗址的7层与6层所出遗存进行比较后,我们认为两者不能归入同一考古学文化。     

Reconstructing the food structure of ancient coastal inhabitants from Beiqian village: Stable isotopic analysis of fossil human bone

The Beiqian site located in Jimo city,Qingdao,a few kilometers from the modern coastline was excavated in 2007,2009 and 2011.A large number of human bones from the early Dawenkou period were unearthed.Through C and N stable isotopic analysis,the food structure of the "Beiqian" ancestors was reconstructed and the influence of terrestrial and marine resources on their lifestyle was discussed.Based on the δ13C and δ15N stable isotopic values of human bone collagen,the analytical results obtained through a ternary mixed model reveal that the food sources of the Beiqian ancestors included about 44.1% marine species(probably shellfish and fish),34.1% C4 plants(possibly millet),and 21.8% land animals.These results indicate that they lived mainly from fishing and farming,supplemented by hunting or poultry raising.Compared with other sites in the same period,the stable isotope results show that 5000-6000 years ago,the lifestyles of ancestors in the Yangtze River basin,Yellow River basin,Northern coastal area and inland area were very different.The ancestors from the Yangtze River basin focused on rice farming and fishing,whereas the ancestors in the Yellow River basin farmed millet and raised animals.Those in coastal areas relied mostly on farming and marine fishing.