连续火干扰对攀枝花干热河谷地表蚂蚁群落的影响

为了弄清攀枝花干热河谷连续火干扰林地地表蚂蚁多样性及其指示作用,在攀枝花市境内3种类型样地采用陷阱法对地表蚂蚁群落和植被群落进行调查.结果表明:攀枝花干热河谷3种类型样地表蚂蚁群落由4亚科16属21种组成,共1 878头;3种类型样地中,攀枝花公园蚂蚁多度和多样性水平最高;在3种类型的样地中,蚂蚁群落结构有差异,但同德林场火干扰样点与未火干扰样点群落结构较相似;同德林场短期未被火干扰栖境无指示物种,攀枝花公园和同德林场连续4 a火干扰样地均存在指示物种.研究表明具有连续火干扰的“计划烧除”可以在预防大面积火灾的前提下,在一定程度上保持蚂蚁群落较高的多度和较稳定的物种多样性水平,对提高区域生物多样性具有积极作用.     

黄河下游湿地芦苇种群克隆结构的等位酶分析

以等位酶为标记，采用水平切片淀粉凝胶电泳技术，对黄河下游湿地15个芦苇(Phragmites australis (Cav.) Trin.ex Steud)群的克隆结构进行了初步研究．8个酶系统17个等位酶位点的检测表明，芦苇种群克隆多样性很高，基因型比率PD=0．53(0．10—0．85)，不同克隆在规模上相差很大．克隆结构分析表明，芦苇种群内克隆之间的镶嵌明显．     

Clonal evolution in relapsed acute myeloid leukaemia revealed by whole-genome sequencing

Most patients with acute myeloid leukaemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level. To determine the mutational spectrum associated with relapse, we sequenced the primary tumour and relapse genomes from eight AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to define clonality and clonal evolution patterns precisely at relapse. In addition to discovering novel, recurrently mutated genes (for example, WAC, SMC3, DIS3, DDX41 and DAXX) in AML, we also found two major clonal evolution patterns during AML relapse: (1) the founding clone in the primary tumour gained mutations and evolved into the relapse clone, or (2) a subclone of the founding clone survived initial therapy, gained additional mutations and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific versus primary tumour mutations in all eight cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped, in part, by the chemotherapy that the patients receive to establish and maintain remissions.     

浅谈库区农村移民安置的小城镇建设及途径

城镇是各种生产要素的集聚中心,具有重要的综合功能,是三峡工程农村移民安置的主要场所,同时符合农村移民心态,具有吸纳大量移民的潜力.小城镇安置农村移民有利有弊,在实际工作中要解决好科学规划、投资体制、土地使用、户籍改革等问题.     

火灾条件下气溶胶灭火剂固体微粒沉降过程分析

对火灾下气溶胶灭火剂固体微粒的空间分布特点及沉降过程进行了非稳态分析，给出了微粒粒径对其运动状态的影响特征，对固体微粒在流场中的稳定性及滞留时间进行了研究，获得了微粒到达火源表面的临界粒径表达式。结果表明，微粒沉降过程其沉降的雷诺数与粒子直径相关，且基本处于低雷诺数状态，沉降速度与微粒粒径的平方成正比。当微粒直径小于100 μm时，将在很短时间内达到相对稳定的流动状态；当微粒直径达到1 μm时，可在空间中长期滞留，并通过卷吸进入火焰区域，达到灭火的效果。     

小型局域网络硬件的一个实现方案

本文介绍了建立小型局域网的一个硬件实现方案。     

Pretender punishment induced by chemical signalling in a queenless ant

Animal societies are stages for both conflict and cooperation. Reproduction is often monopolized by one or a few individuals who behave aggressively to prevent subordinates from reproducing (for example, naked mole-rats, wasps and ants). Here we report an unusual mechanism by which the dominant individual maintains reproductive control. In the queenless ant Dinoponera quadriceps, only the alpha female reproduces. If the alpha is challenged by another female she chemically marks the pretender who is then punished by low-ranking females. This cooperation between alpha and low-rankers allows the alpha to inflict punishment indirectly, thereby maintaining her reproductive primacy without having to fight.     

利用蚁群算法进行混匀矿计算优化

针对中小型炼铁企业烧结工艺的要求,以混匀矿SiO2和TFe含量精度,以及混匀矿成本为目标函数,建立了烧结主原料混匀矿配比数学模型,采用蚁群算法对混匀矿配比进行实时优化计算,并利用遗传算法对蚁群算法加以改进,取得了良好效果,保证了堆积物料中SiO2含量和TFe含量与大堆预想成分中含量基本相近的同时降低混匀矿造堆成本．     

在建工程的火灾特征、原因及其防火措施

对在建工程的火灾特征和起火原因进行了分析,从管理制度、日常巡查、消防通道的设置、作业人员的安全教育、临时作业的防火安全注意事项等方面提出了防火对策措施.     

杉木无性系种子园花粉数量的研究

本研究为福建省洋口林场1966年的杉木嫁接种子园,包括42个无性系,200株母树,面积0.7公顷,母树平均树高8—9米。 依据母树“雄球花”的数量和生长状况,把种子园的母树区分为三类,即“簇生”、“混生”、“单生”,从各类母树中随机抽取3～4株作为样株,统计每株母树的“雄球花”数量和每个“雄球花”的花粉数量。 研究结果表明,每一个小孢子囊花粉粒的数量是3700粒,每一小孢子叶球含有264个小孢子囊,而一个“雄球花”又含有26个小孢子叶球,再估算出一个“雄球花”产生大约2540×10~4粒花粉。根据杉木种子园中一株母树的“雄球花”数量和一个“雄球花”的花粉粒的数量来估算每株树产生花粉粒的数量。在三种类型的母树中,每株树的花粉平均数量为532×10~8粒,估算这个无性系种子园所生产的花粉数量约91540×10~8粒。     

激光散斑二次曝光干涉法测量微小位移和形变

分析和讨论了激光散斑二次曝光干涉法测量微小位移和形变的原理及方法,提出了位移散斑图是该测量方法中的关键因素。     

火灾报警及消防联动工程档案的归档范围

火灾自动报警及消防联动的施工中产生的施工文件作为工程档案的重要组成部分,其归档范围没有统一规定,施工企业根据自己的实际情况制定了各自的归档范围,各不一样,文章从质量保证施工文件、施工经济文件、编制竣工图三个方面论述了具体的归档范围.     

单片机火灾检测报警系统

本文介绍了一种智能消防系统.该系统具有用电话拨打119报警,利用步进电机定向、定点灭火等特点.     

Clonal origin of haematopoietic colonies in the postnatal mouse liver

The liver of the neonatal mouse continues to show haematopoietic activity for up to 2 weeks after birth and morphological analysis has shown that this activity becomes focused in discrete haematopoietic colonies by the end of the first week postnatal. Furthermore, each colony contains cells of one haematopoietic lineage only, that is, erythroid, myeloid or pre-B-lymphoid cells. This pattern of differentiation suggests that each colony is derived from a single committed precursor cell, which, if true, would represent the first demonstration of non-mixed haematopoietic colonies in normal development and would provide a useful system for studying the factors affecting the clonal diversity of haematopoietic stem cells and their lineage-committed progeny. Here we have analysed the haematopoietic foci in the liver of neonatal mouse chimaeras, using a newly developed ubiquitous in situ cell marker system which clearly demonstrates the clonal origin of these colonies.     

Two typical phenomena from the numerical simulation of fire and smoke transport in a gymnasium fire

Building a large centralized atrium in a building has become favourable both to designers and owners. The space of an atrium in a hall, theatre or gymnasium, can occupy an area as large as thousands of square meters and a height as high as 10―30 meters[1…