Succession of mosses,liverworts and ferns on coarse woody debris,in relation to forest age and log decay in Tasmanian wet eucalypt forest

In managed forest landscapes, understanding successional processes is critical to management for sustainable biodiversity. Coarse woody debris is a key substrate for forest biodiversity, particularly because it undergoes complex succession reflecting the effects of changes in both forest structure and substrate characteristics. The present study used a chronosequence approach to investigate succession of mosses, liverworts and ferns on coarse woody debris following clearfell, burn, sow native forest silviculture in wet eucalypt forest in Tasmania, focussing on discriminating between the effects of forest age and log decay. It also compared successional processes following wildfire with those following clearfell, burn, sow silviculture. Forest regenerating after the latter form of regeneration showed clear ecological succession up to 43 years (the limit of available sites), characterised by increasing diversity and cover, and clearly delineated specialisation among species with regard to successional stage. Analyses of subsets of the full data-set indicated that the effects of forest age dominated this succession, with minimal effects of substrate change independent of forest age. Analysis of within forest microenvironments were consistent with the inference that microenvironmental changes related to forest age drive major successional changes in these forests. Comparative analysis indicated similarity between successional states in post-wildfire and post- clearfell, burn, sow regeneration after 43 years for logs of the same decay stages, and continuing succession on post-wildfire sites to at least 110 years. Overall, these data suggest that management to sustain fern and bryophyte diversity should ensure that areas of forest beyond 110 years are represented in the landscape at appropriate spatial scales.     

基于尺度推绎方法的生态脆弱区耕作适宜性研究——以山西省寿阳县为例

以山西寿阳县的玉米和小麦为研究对象,应用尺度推绎方法开展机械化与传统耕作方式下区域粮食作物耕作适宜性的对比研究。结果表明：（1）传统耕作方式下玉米与小麦适宜种植面积皆要大于机械化耕作方式下两种作物适宜种植面积,而无论是机械化种植还是传统耕作小麦适宜种植区面积皆大于玉米种植适宜区.（2）两种作物种植适宜区空间分布呈两极化特征,即高度适宜区与永久非适宜区占据研究区绝大部分区域.（3）两种粮食作物高度种植适宜区基本集中在寿阳县北部黄土高原的塬、沟地貌区及坡度较小的山区。建议在机械化种植与传统耕作方式下皆是中、高度种植适宜区域采取机械化种植方式,而在仅适宜传统耕作的种植适宜区采取传统方式耕作。     

小麦品种区域试验四种分析方法的比较研究

为探求更加方便、快捷、有效的小麦品种区域试验分析方法,以2008-2009年度河南省小麦品种区域试验结果为资料,对作物品种区域试验中方差分析、模糊综合评判方法、灰色多维综合评估方法和同异联系势分析方法进行了比较研究。结果表明,四种分析方法各有千秋,方差分析理论与方法较为成熟,但只能分析单一性状,综合功能差;其余三种分析方法则综合功能强,对品种评价更加客观、全面。其中,灰色多维综合评估方法和同异分析方法区分度较好,更利于辨别品种优劣,尤其是同异分析方法计算简单,方便快捷,提供的试验信息更多,能够对多个性状进行综合差异显著性检验,是开展育种工作的良好工具和手段。     

3种棒果芥属植物生物量分配及异速生长分析

类短命植物是准噶尔荒漠早春草本植物类群的重要而独特的组成部分,研究其生物量分配和异速生长关系,有助于深入了解类短命植物的生存策略与生态功能。以棒果芥（ Sterigmostemum tomentosum ）、福海棒果芥（ S ． fuhaiense ）和黄花棒果芥（ S ． sulfureum ）为研究对象,采用挖掘法获取野外成株全株生物量,对三者的器官生物量、分配比例及异速生长关系进行了对比分析。结果表明,3种植物器官生物量及其分配比例均差异明显。福海棒果芥生物量最大,但根冠比（R／S）和叶冠比（L／S）最小;棒果芥生物量最小,但L／S最大;黄花棒果芥则具有最大的R／S。棒果芥和黄花棒果芥的根冠比（R／S）均随个体的增大而显著下降,表明二者地上（AGB）与地下生物量（BGB）分配受到个体大小的强烈影响。福海棒果芥AGB－BGB间为等速生长关系（幂指数α＝1）,而另外2种均为异速生长关系;棒果芥、福海棒果芥的叶生物量（LB）与AGB间为等速生长关系,而黄花棒果芥符合异速生长关系（α＜1）;3个物种的LB－BGB间具有共同的异速生长指数（0．816）,表现出强烈的功能趋同性。总之,3个物种间的生物量分配及异速生长关系没有一致规律,但体现了类短命植物生物量分配的特点。     

热水锅炉防垢措施研究

通过分析热水锅炉结垢机理,提出强制提高受热面内水流的流速和降低循环水补水量两大防垢措施,探讨开展热水锅炉防垢研究的重要意义,为提高热水锅炉安全性提供理论借鉴。     

论非艺术类高校文化艺术社团多维度建设

目前,全国有很多非艺术类高校,因在专业支撑、师资配备、生源基础、招生政策扶持等方面的"先天不足",艺术教育处于无场地、无经费、无编制的"三无"状态。对于非艺术类高校来说,文化艺术社团建设是加强艺术教育的重要手段。非艺术类高校文化艺术社团多维度建设的意义和价值在于:文化艺术社团通过活动辐射、熏陶、造就学校文化艺术氛围,不断提升学生的综合能力,对校园文化的形成具有相互的辐射和先导作用,引领非艺术类高校先进文化艺术发展。非艺术类高校文化艺术社团多维度建设可以通过多种渠道保证大学生文化艺术社团扶持力度,提高艺术教育水平重在指导教师来源多元化,建立大学生参加艺术社团的激励措施等三大举措加以推进。更重要的是,非艺术类高校文化艺术社团多维度建设中长效机制的建设:专业化的外部管理、规范化的内部管理、任务活动多样化的管理、网络化的宣传鼓励。     

Molecular diversity of bacterial chitinases in arable soils and the effects of environmental factors on the chitinolytic bacterial community

The molecular diversity of bacterial chitinases in the bulk soils of arable land was investigated using culture-independent methods. The results demonstrate that bacterial chitinases in arable soils are highly diverse and comprise unique groups when their sequences were compared to those in public databases. The diversity of bacterial chitinases in arable soil was further evaluated using conventional phylogenetic analysis, the UniFrac analysis of the phylogenetic data, and the multidimensional scaling (MDS) analysis of T-RFLP profiles to elucidate the relationship between the diversity of bacterial chitinases and soil characteristics. These analyses indicate that environmental factors such as soil type and pH are responsible for shaping the composition of bacterial chitinases.     

潜水泵缩比模型的相似性验证与内部流场分析

相似换算设计法是离心泵设计中最常用的方法之一。为了验证缩比模型的相似性,该文选取一典型井用潜水泵作为模型泵,基于缩比模型换算法获得设计泵,借助数值模拟与性能试验的方法,研究设计泵与模型泵的相似性,并分析两者内部流场的差异与规律。采用Ansys CFX软件分别对设计泵和模型泵进行数值模拟,以两级泵模型建立计算域,划分结构化网格,基于标准k-?湍流模型和标准壁面函数进行多工况数值模拟,分别对设计泵和模型泵进行了性能预测,并对预测结果进行了对比分析。结果表明:较于模型泵,设计泵的最大功率点向大流量工况偏移,且最大功率与额定功率的比值有所上升,但其仍具有较好的无过载特性。模型泵数值预测与试验结果的对比表明,在额定流量下,数值模拟预测的扬程低于试验结果 0.79%,功率低于试验值5.2%,效率高于试验值2.78%,且两者随流量变化的趋势基本一致,说明该文的数值计算结果具有一定的准确性。缩比模型在0.4~1.6倍额定流量工况范围内,扬程、效率和功率随流量变化趋势基本一致,设计泵与模型泵满足相似换算准则,模型等比例缩放法能够满足深井离心泵的水力设计要求。     

带鱼保护区春秋季鱼类群落特征及与环境因子的关系

基于2014年5月(春季)和11月(秋季)在带鱼保护区进行的渔业资源底拖网调查数据,采用非度量多维标度(NMDS)、典范对应分析(CCA)和分类回归树(CART)方法研究了带鱼保护区春、秋季鱼类群落空间结构和群落多样性,以及它们与环境因子的关系。结果显示,该水域春季共捕获鱼类75种,隶属14目49科63属;秋季捕获鱼类78种,隶属15目50科64属。春、秋两季鱼类空间结构均可划分为2个组群,经单因子相似性(ANOSIM)分析,不同季节的2个组群间均存在显著性差异。CCA分析表明,影响春、秋季鱼类群落分布的主要环境因子有温度、盐度、水深以及浮游动物。春季多样性指数平均值为1.65±0.60,丰富度指数为2.46±0.90,秋季多样性指数平均值为1.42±0.53,丰富度指数为1.89±0.60。CART分析表明,影响春季多样性和丰富度的主要因素有Chl.a、DO、水深、p H和浮游动物(磷虾类和浮游幼体);秋季多样性主要受温度、水深和盐度的影响,丰富度主要受水深和温度的影响。     

The scaling of bite force and constriction pressure in kingsnakes (Lampropeltis getula): Proximate determinants and correlated performance

Across the diversity of vertebrates, bite force has been studied and suggested to have important ecological and evolutionary consequences. However, there is a notable lineage of vertebrates that use this performance trait yet are missing from the bite‐force literature: the snakes. Snakes often rely on biting during prey subjugation and handling. Many snakes bite and hold prey while a constriction coil is formed or while venom is being delivered, or both. Others use biting exclusively without employing any additional prey‐handling behaviors. In addition to biting, constriction is an important predation mechanism. Here, I quantify bite force and constriction pressure in kingsnakes (Lampropeltis getula). Furthermore, I explore the proximate determinants of bite force as well as the relationship between biting and constriction performance. Bite force increased linearly with all head and body measures. Of these, head height was the best predictor of bite force. Bite force in kingsnakes was within the range of values reported for lizards, but their relative performance was lower for their head size compared to lizards. Peak constriction pressure also increased with all body measures. Biting and constricting use 2 different parts of the musculoskeletal system and are positively and significantly correlated with one another. Future work targeting a greater diversity of snakes that rely more heavily on biting may reveal a greater range of bite performance in this diverse and successful vertebrate group.