基于深度学习的多STBC盲识别算法

针对空时分组码(space-time block code, STBC)识别中多种编码类型难区分的问题, 提出了一种基于卷积神经网络的STBC盲识别算法。该算法首先将接收信号采用自相关函数的频域预处理, 输入到卷积神经网络中对信号特征进行提取, 全连接层对特征进行映射, 实现对6种STBC类型的识别。仿真实验结果表明, 在无信道和噪声等先验信息的条件下, 所提算法能够有效区分3种相似度高的STBC3码, 且将STBC可识别的编码类型由目前的4种扩充到6种, 识别准确率能达到96%。该方法的复杂度较低, 不需要利用大量样本数据, 实时性高, 具有较好的工程应用价值。     

中国南方沿海13种石斑鱼类的分子系统进化关系分析

石斑鱼类(Groupers)是世界性海洋经济鱼类,也是中国南方沿海省份重要的海水增养殖对象,其种类繁多,由于缺乏明显的种间外部形态区别特征,石斑鱼的分类一直是鱼类系统分类学的一个难题,存在着较多的争议和混淆。为了从分子水平揭示石斑鱼类的系统进化关系,应用线粒体细胞色素b基因(Cyt b)及两个核糖体RNA基因(16S和12S)序列联合构建系统进化树对中国近海石斑鱼亚科3属13种进行种类鉴定及亲缘关系分析,探讨了石斑鱼类的分子系统进化。结果表明:①线粒体基因序列在石斑鱼类种间存在较大的变异,种内变异极小,是进行石斑鱼类种类鉴定较为适宜的分子标记;②所研究的3属13种石斑鱼类中,石斑鱼属与九棘鲈属的亲缘关系较近,与鳃棘鲈属的较远;③赤点石斑鱼和青石斑鱼、蜂巢石斑鱼与鲑点石斑鱼、斜带石斑鱼与棕斑石斑鱼两两间具有较近的亲缘关系。     

h-1保持各种独立语言的条件

设h：X＊→X＊是同态映射,主要研究了h-1保持各种独立语言的条件.得到了h-1保持ρc-独立语言,ρd-独立语言以及ρb-独立语言的充分必要条件都是h-1（1）={1}.此外,证明了若h：X＊→＊是同态映射,则h-1保持ρe-独立语言.     

miR-26b和miR-224在梅山与杜洛克猪卵泡中的差异表达分析

为了探讨miRNAs在猪卵泡和繁殖相关组织中的表达,采用荧光定量RT-PCR法和组织表达谱分析法,对miR-26b和miR-224在梅山和杜洛克猪卵泡及其他繁殖相关组织中的表达进行了研究。组织表达谱分析结果表明:miR-26b和miR-224在下丘脑、垂体、子宫、输卵管、卵巢、子宫角、黄体组织中均有表达。RT-PCR结果表明:miR-26b在L卵泡中的表达量梅山猪是杜洛克猪的2倍(P0.01);而在S卵泡中的表达量杜洛克是梅山猪的10倍(P0.01);两品种在M1和M2卵泡中的表达量差异不显著。miR-224在S卵泡中的表达量杜洛克是梅山的7.79倍(P0.01);而在M2卵泡中表达量梅山是杜洛克的1.84倍(P0.05);两品种在M1和L卵泡中的表达量差异不显著。在猪种内大卵泡L、中等卵泡M2、中等卵泡M1、小卵泡S的相对表达量也有不同程度的差异。此研究表明,miR-26b和miR-224在梅山和杜洛克猪中表达趋势相似,它们的表达差异可能影响卵泡发育和成熟,为深入了解miR-26b和miR-224在卵泡发育中的作用奠定了基础。     

Preliminary report on the genetic structure of Glyphoglossus molossus (Anura: Microhylidae) from the Khorat Plateau,north-eastern Thailand

Glyphoglossus molossus, is one of the most economically important amphibians in the Khorat Plateau, north-eastern Thailand. It is categorised as a near-threatened species by IUCN due to over-exploitation. Here, we examined the genetic structure of G. molossus using partial mitochondrial cytochrome-b gene sequences from specimens collected at 11 localities. The sequence analysis revealed the presence of 15 haplotypes, 5 of which are shared by 2 or more populations, and 10 haplotypes that are confined to a single population. The relatively low haplotype (h) and nucleotide (π) diversities suggest that the Phu Phan Mountain Range is not high enough to act as an effective dispersal barrier between the Sakon Nakhon and Khorat Basins. However, AMOVA and phylogenetic analyses based on Maximum likelihood (ML) and Bayesian inference (BI) strongly supported the presence of two genetically divergent clades, Sakon Nakhon Basin and the northern part of the Khorat Basin (clade A) and the southern part of the Khorat Basin (clade B). These two lineages are separated by substantial geographical distance, which has putatively resulted in a reduction of gene flow. Further studies, with more extensive genetic sampling, especially from throughout the species range will aid in better interpreting our results.     

新型苯基醚类苯并呋喃衍生物的合成

以水杨醛与2-溴-4’-氟苯乙酮为原料,合成2-(4-氟苯甲酰基)苯并呋喃,进一步与酚反应,合成得到6个新的苯基醚类苯并呋喃衍生物(2a~2f),其结构经IR、1H NMR和13C NMR进行了表征.     

Geographical variation in the golden‐striped salamander,Chioglossa lusitanica Bocage, 1864 and the description of a newly recognized subspecies

Morphological and genetic data for the Iberian golden‐striped salamander, Chioglossa lusitanica, demonstrate the existence of two groups with southern and northern ranges, connected by a zone of intergradation in central Portugal. Because reproductive isolation between them is incomplete we consider the groups to be subspecies. The type locality of C. lusitanica (Buçaco near Lousã) is situated inside the mixed zone. This necessitates identification of the nominotypical subspecies. We sequenced a fragment of mitochondrial DNA from one of the species' syntypes and we determined what position over a latitudinal transect maximizes the morphological discrimination between the groups. Both approaches indicate that C. lusitanica from Buçaco represents the southern subspecies. A new subspecies of C. lusitanica is described from a northern locality (Valongo near Porto in north‐western Portugal). A lectotype is designated for Chioglossa lusitanica.     

浅谈动作技能形成中创造性思维的培养

体育教学的任务之一，是培养学生的动作技能，而动作技能的学习和掌握是智力和体力活动的结合，需要思维，尤其是创造性思维的参与。本文就创造性思维在体育运动中的特点谈谈在动作技能形成过程中创造性思维的培养。     

关于正整数解（a,b,k）型可加划分的一个注解

讨论在a是偶数 ,b与k都是奇数 ,且a≥ - 2k ,-k≤b <- 2k的条件下 ,(a ,b,k) (k <0 )型可加划分存在的充要条件 ,以及划分个数的计算公式     

黄河鮈Cytb基因克隆及其在鮈属中的系统发育

采用聚合酶链式反应克隆黄河鮈线粒体细胞色素b基因 (Cyt b),首次报道了该基因的全长序列(1140bp,FJ904648) ,并与鮈属中其他6个物种的Cyt b 基因进行同源性比较,分析了碱基组成和变异情况,以马口鱼属的马口鱼和鯝属的云南鯝作为外群构建了ML和NJ系统发育树.遗传距离和分子系统学分析表明,黄河鮈与犬首鮈具有较低的遗传距离(6.30%),在系统发育树上两者聚在一起,提示黄河鮈与犬首鮈存在较近的亲缘关系.