黔西南廖基金矿地质特征及金的赋存状态研究

廖基金矿位于滇黔桂"金三角"北部晴隆-罗平成矿带之碧痕营穹窿北东翼,根据黔西南地区金矿找矿建立的以构造蚀变体(SBT)为核心的成矿模式,通过钻探工程验证,发现了赋存于构造蚀变体(SBT)中的金矿体,初步探获金资源量为小型矿床规模,容矿岩石主要为角砾状凝灰岩、角砾状凝灰质玄武岩、角砾状灰岩及角砾状黏土岩,与金矿成矿关系密切的热液蚀变主要有褐铁矿化、硅化、黄铁矿化,金主要以包裹金形式存在于硅酸盐矿物和硫化物中,其平均占有率分别为37.52%、35.90%,强风化至中风化矿石中的金主要以游离金形式存在。

禽类β-防御素的研究进展

禽类β-防御素是一种小的阳离子非糖基化的多肽,仅存于禽类体中,不仅具有广谱的抗菌活性,还在禽类的免疫调节方面扮演着重要的角色。文章讨论了禽类β-防御素的结构、在组织中的分布、进化、抗菌特性和免疫活性,介绍了禽类β-防御素的国内外研究进展。

反刍动物肠道菌群对饲料利用效率调节效应的研究进展

饲料消耗是动物养殖中的主要支出环节,提高饲料利用效率对提升畜牧效益具有重要意义。肠道是反刍动物重要的消化器官和免疫器官,而其中定植的菌群在宿主消化吸收和能量代谢中发挥关键作用,反刍动物的肠道菌群对饲料利用效率具有重要的调节作用。因此,本文重点对反刍动物肠道菌群的特征、对饲料利用效率的调控机理以及常用的调控手段等方面进行了综述,以期为相关研究提供一定的科研数据支撑。

羊毛性状相关蛋白、信号分子及基因的研究进展

羊毛不仅有维持体温和保护作用,而且具有独特的经济价值。随着国内外对羊毛性状相关基因研究的深入,一系列羊毛性状相关的蛋白、信号分子及基因被陆续发现。本文结合国内外现有的研究,对羊毛和毛囊结构的生长发育特点、角蛋白中间丝蛋白(Keratin Intermediate Filaments Proteins,KIFs)和角蛋白关联蛋白(Keratin-Associated Proteins,KAPs)相关蛋白、Wnt家族和成纤维细胞生长因子家族(Fibroblast Growth Factors,FGFs)等有关信号分子以及与羊毛性状相关的KAPs等基因进行综述,旨在理解羊毛毛囊形态发生和周期性生长机制,即生长期(Anagen)、退行期(Catagen)和休止期(Telogen),为进一步挖掘与羊毛性状相关的蛋白与功能基因提供思路,为今后羊毛产业与毛用羊的选育以及生产性能的提高提供理论参考。

Surface characteristics and wetting mechanism of respirable coal dust

In this study,FTIR and XPS spectroscopy,specific surface area and pore size analyses,wetting and other experimental means have been applied to investigate respirable coal dust surface properties and wetting mechanism.The research shows that coal dust surface structures,chemical and element compositions are changed in the refining process of coal dust.Compared with large particle coal dust,respirable coal dust is a weak hydrophilic and strong hydrophobic substance.The reason:the smaller the particle size of coal dust,the more unsaturated its surface.The absorption of air is strong and it is easy to form an air film on coal dust surfaces. Coal dust contact with water is actually a compound contact of liquid in contact with a solid and gas in contact with a solid. The smaller the particle size,the larger the pore volume and the higher the degree of surface roughness,the larger the area of gas in contact with a solid and the worse the coal dust wettability.Another reason is that the changes in the composition of atoms on the dust surface and structures affect coal dust wettability.The results of this study establish a theoretical basis for the invention of effective reduced-dust technology.

青藏高原疏勒河上游不同类型冻土可培养细菌多样性特征研究

在气候变暖及人类活动的双重干扰下,疏勒河上游冻土发生了显著退化,如活动层厚度加大、植被退化等,而冻土退化对微生物的影响一直是科研人员关注的热点话题。以疏勒河上游不同季节(4月、6月、9月)、不同退化程度冻土为研究对象,研究了可培养细菌多样性特征。通过16S r DNA基因测序及构建系统发育树表明,研究区域可培养细菌归类为27个属,分属于α-变形菌门,γ-变形菌门,放线菌门,厚壁菌门和拟杆菌门,其中放线菌门为优势类群。从属水平来讲,可培养细菌以节杆菌属和微球菌属为主,其含量随冻土退化程度加深分别呈下降和升高趋势。土壤细菌多样性与环境因子的相关性分析表明,可培养细菌多样性与土壤含水量、总氮极显著正相关,与有机碳显著正相关。这些结果表明,伴随着冻土退化而发生的地上植被逆向演替过程中,青藏高原不同类型冻土间已产生较大的环境异质性如土壤碳氮及含水量,进一步可能导致冻土微生物多样性分异。研究结果为利用微生物综合评价青藏高原不同类型冻土的生态环境提供了数据基础。

Bacterial diversity in the sediment of Crescent Moon Spring,Kumtag Desert,Northwest China

Desert lake, a unique oasis in desert ecosystems, harbours different bacterial communities. Thus, it is considered as a hub of bacterial diversity. In this study, bacterial diversity in the sediment of Crescent Moon Spring, Kumtag Desert, Northwest China was analyzed using high-throughput amplicon pyrosequencing analysis. The sequences of the most abundant OUTs （Operational Taxonomic Units） in the sediment of Crescent Moon Spring were compared with the sequences of those most abundant OUTs of various origins from NCBI GenBank database to detect the origins of bacteria in the sediment of Crescent Moon Spring. Also, bacterial compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide were compared using cluster analysis to determine the possible factors affecting bacterial compositions. In total, 11,855 sequences were obtained and 30 phyla were identified. At the phylum level, the dominant phylum was Proteobacteria with α-Proteobacteria being the first dominant class and the second dominant phylum was Planctomycetes. Our finding that α-Proteobacteria being the first dominant class of Proteobacteria and Planctomycetes being the second dominant phyla are somewhat contradictory with reports from other desert lake sediments. This difference could be resulted from water hydration and conductivity, as well as oligotrophic conditions of Crescent Moon Spring. At the genus level, Rhodobacter, Caldilinea, Planctomyces, and Porphyrobacterwere the dominant genera in the sediment of Crescent Moon Spring. Comparisons on sequences of the most abundant OUTs （including OTU3615, OTU6535, and OTU6646） between sediment of Crescent Moon Spring and various origins from NCBI GenBank database indicate that the origins of bacteria in the sediment of Crescent Moon Spring are likely from the underground water. Furthermore, cluster analysis on comparisons of bacteria compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide shows that at regional scales, bacterial compositions may be mainly affected by geographical patterns, precipitation amounts, and pH values. Collectively, our results provide new knowledge on the bacterial diversity in desert lake ecosystems.

基于频域稀疏自编码网络的音乐分离技术

音乐分离技术通常是将歌曲中的伴奏和干声进行分离,或者是将干声、贝斯、鼓点等成分进行分轨,具有较高的学术研究价值和商业价值。音乐分离可以应用于重新混音编曲、伴奏库生成以及MIDI信息获取等。近几年,基于深度学习的音乐分离方法取得了极大进展,Spleeter方法和Demucs方法极大地提高了音乐的分离质量。但是,音乐分离任务中分离伴奏的完整性、分离引入的失真等问题依然没有得到很好地解决,因此试图提出了一种基于频域稀疏自编码网络结构来提高音乐分离的效果。它的核心思想是使用编码器-解码器框架对频域信号进行建模,并采用CNN网络对编码器输出结果进行源分离任务。该方法提升了分离伴奏的保真度,提高了分离算法的效率和稳定性。MUSDB18测试集上的实验结果表明,该方法在多个客观指标上都达到了最优。

东方雄狮无坚不摧——面对突如其来的新冠疫情 中国人民交了一份合格的考卷

目前仍在肆虐蔓延的新型冠状病毒肺炎(新冠肺炎)疫情在人类历史进程中无疑将留下深深的印记。网络戏称:在抗击新冠肺炎疫情的世界大战中,中国打上半场,世界打下半场;中国是闭卷考试,世界是开卷考试。虽然疫情尚未结束,但考试结果已基本明了……有道是"事实胜于雄辩",人们不禁要思考:为什么作为世界上最大的发展中国家,中国在这场席卷全球的战役中能有如此出色的表现?毫无疑问,体制与制度的优势无可争辩。