全岩显微组分统计方法及应用

本文对实验室全岩显微组分统计方法及应用进行了讨论。提出全岩有机质类型和丰度评价标准,能有效地评价烃源岩的优劣,并可划分出全岩有机质类型。与干酪根镜检方法相比较,具有明显的优越性,能提供更丰富的信息,而且分析速度快、节省成本、直观。     

Amplification of siRNA in Caenorhabditis elegans generates a transgenerational sequence-targeted histone H3 lysine 9 methylation footprint

Exogenous double-stranded RNA (dsRNA) has been shown to exert homology-dependent effects at the level of both target mRNA stability and chromatin structure. Using C. elegans undergoing RNAi as an animal model, we have investigated the generality, scope and longevity of dsRNA-targeted chromatin effects and their dependence on components of the RNAi machinery. Using high-resolution genome-wide chromatin profiling, we found that a diverse set of genes can be induced to acquire locus-specific enrichment of histone H3 lysine 9 trimethylation (H3K9me3), with modification footprints extending several kilobases from the site of dsRNA homology and with locus specificity sufficient to distinguish the targeted locus from the other 20,000 genes in the C. elegans genome. Genetic analysis of the response indicated that factors responsible for secondary siRNA production during RNAi were required for effective targeting of chromatin. Temporal analysis revealed that H3K9me3, once triggered by dsRNA, can be maintained in the absence of dsRNA for at least two generations before being lost. These results implicate dsRNA-triggered chromatin modification in C. elegans as a programmable and locus-specific response defining a metastable state that can persist through generational boundaries.     

高性能基音检测新方法

本基音检测方法是利用汉语语音结构特点,以主循环为基本概念,在时域上处理确定浊音音段的基音,而对清浊不明晰的音段,从时、频域两方面进行基音估算,并设计了基音选择逻辑和清浊音判断逻辑。实验结果表明,本方法的性能明显优于大多数流行的基音检测器,且计算速度快,是自相关方法和倒谱法的４倍和８倍。     

出光窗口对高密度LED性能影响的研究

针对LED高密度光源,探索了出光窗口对器件性能产生影响的原因.通过热学模拟与实物样品的物理性能测试,比较不同出光窗口对器件性能与可靠性的影响.结果表明：出光窗口可以增加LED芯片的散热通道,同时也会影响LED的可靠性;出光窗口会造成一部分光能量的损失,特别是拥有荧光转化功能的窗口,会因荧光转化而产生热量,且产生的热量会因为窗口基体材料的不同呈现不同的结果;荧光转换率高且热导率高的荧光材料,应用于高密度LED器件时,可有效降低荧光转换热量,且能加快荧光转换产生热量导出的速度,提高器件的发光效率与可靠性.     

大学生论辩能力构建研究

近年来,论辩能力因其体现了诸多能力而倍受教育者和学者的关注。话语辩论模式能有效提高学生论辩能力,增强学生合作意识及团队精神。实践证明,对学生采用合理的学习指导及必要合理的监控,能够有效地提高大学生的论辩能力,提高学生的综合素质,进而达到培养高素质人才和创新人才的教学目的。     

Inclusive fitness theory and eusociality

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.     

Observations of reproduction in mountain lions from Nebraska

Occurrences of mountain lions ( Puma concolor ) in Nebraska have been steadily increasing; however, reproductive activity in mountain lions has not been documented in the state. We present the first evidence of mountain lion reproduction in Nebraska since mountain lions recolonized the state in the early 1990s. On 28 February 2007, a spotted kitten was hit by a vehicle in northwestern Nebraska; and based on body length and weight, we estimate its age at 3.9 months. On 20 December 2008, a female mountain lion and spotted kitten were photographed in the northwestern part of the state. On 9 May 2009, a female mountain lion with a juvenile was also photographed. All records were from the Pine Ridge region of Dawes County, Nebraska. Our records suggest that mountain lions are establishing a permanent population in at least one region of Nebraska.     

High-throughput decoding of antitrypanosomal drug efficacy and resistance

The concept of disease-specific chemotherapy was developed a century ago. Dyes and arsenical compounds that displayed selectivity against trypanosomes were central to this work, and the drugs that emerged remain in use for treating human African trypanosomiasis (HAT). The importance of understanding the mechanisms underlying selective drug action and resistance for the development of improved HAT therapies has been recognized, but these mechanisms have remained largely unknown. Here we use all five current HAT drugs for genome-scale RNA interference target sequencing (RIT-seq) screens in Trypanosoma brucei, revealing the transporters, organelles, enzymes and metabolic pathways that function to facilitate antitrypanosomal drug action. RIT-seq profiling identifies both known drug importers and the only known pro-drug activator, and links more than fifty additional genes to drug action. A bloodstream stage-specific invariant surface glycoprotein (ISG75) family mediates suramin uptake, and the AP1 adaptin complex, lysosomal proteases and major lysosomal transmembrane protein, as well as spermidine and N-acetylglucosamine biosynthesis, all contribute to suramin action. Further screens link ubiquinone availability to nitro-drug action, plasma membrane P-type H(+)-ATPases to pentamidine action, and trypanothione and several putative kinases to melarsoprol action. We also demonstrate a major role for aquaglyceroporins in pentamidine and melarsoprol cross-resistance. These advances in our understanding of mechanisms of antitrypanosomal drug efficacy and resistance will aid the rational design of new therapies and help to combat drug resistance, and provide unprecedented molecular insight into the mode of action of antitrypanosomal drugs.     

Proton-proton correlations observed in two-proton radioactivity of 94Ag

The stability and spontaneous decay of naturally occurring atomic nuclei have been much studied ever since Becquerel discovered natural radioactivity in 1896. In 1960, proton-rich nuclei with an odd or an even atomic number Z were predicted to decay through one- and two-proton radioactivity, respectively. The experimental observation of one-proton radioactivity was first reported in 1982, and two-proton radioactivity has now also been detected by experimentally studying the decay properties of 45Fe (refs 3, 4) and 54Zn (ref. 5). Here we report proton-proton correlations observed during the radioactive decay of a spinning long-lived state of the lightest known isotope of silver, 94Ag, which is known to undergo one-proton decay. We infer from these correlations that the long-lived state must also decay through simultaneous two-proton emission, making 94Ag the first nucleus to exhibit one- as well as two-proton radioactivity. We attribute the two-proton emission behaviour and the unexpectedly large probability for this decay mechanism to a very large deformation of the parent nucleus into a prolate (cigar-like) shape, which facilitates emission of protons either from the same or from opposite ends of the 'cigar'.