Little-known and phylogenetically obscure South African estuarine microgastropods (Mollusca: Truncatelloidea) as living animals

Areas of the Knysna estuarine bay in the Western Cape are dominated by three endemic South African truncatelloid microgastropods, temporarily known as ‘Hydrobia’ knysnaensis (Krauss), ‘Assiminea’ capensis (Sowerby) and ‘Assiminea’ globulus Connolly. Although first described 80–170 years ago and present in abundance (up to 100,000 m^?2), they remain surrounded by confusion and still await taxonomic assignment, largely because they appear most atypical members of their groups by virtue of anatomy and/or biogeography and/or habitat. This study contributes in-life perspectives to morphological and phylogenetic analyses known to be on-going. At Knysna, they are syntopic: at least two occurring in >85% and all three in >40% of individual 0.0026 m² samples from their region of dominance. Nevertheless, they tend to greater abundance in divergent microhabitats; ‘A.’ globulus dominating higher tidal levels, and ‘A.’ capensis and ‘Hydrobia’ lower ones; the former especially unvegetated sediment, the latter, if anything, seagrass. Interspecific feeding interactions appear unlikely to be responsible for these patterns, other evidence suggesting that all are maintained below carrying capacity. Field biology of ‘H.’ knysnaensis generally appears equivalent to that of northern-hemisphere intertidal hydrobiids and that of ‘A.’ globulus is typically assimineid, albeit at atypically low shore height. Unlike assimineids, however, ‘A.’ capensis is truly aquatic. The success of these truncatelloids in unusual circumstances may be consequent on the absence from South Africa of other microgastropod groups that fill their niches elsewhere in the southern hemisphere.     

基于弦振动测量金属细线的线密度

提出了一种测量金属细线线密度的新方法,并对测量原理、公式进行了较为详细的推导,将测量结果与标准值进行了比较.从测量结果可知,其相对误差较小,说明利用该方法测量细线的线密度确实可行.     

冬枣贮藏效果与相关酶活性的相关研究

以鄂北冬枣为材料,对果实采后低温贮藏过程中相关酶活性与果实硬度进行相关分析、通径分析和灰色关联分析。分析结果表明,各相关酶活性与硬度的相关程度依次为PG、SOD、CAT、PME、POD,与果实硬度的贡献率大小依次为PG、CAT、SOD、PME、POD,与果实硬度的关联度顺序为PME、SOD、PG、CAT、POD。综合分析结果表明,PG活性、CAT活性、SOD活性为果实贮藏过程中主要的酶,在贮藏过程中对果实软化衰老起重要作用。     

CSS代码命名规则与技巧探讨

合理、科学地对CSS代码命名,能够精简CSS代码,提高代码的开发效率,方便网站设计师对网站进行维护与修改.通过对CSS代码命名规则分析,提出了进行语义化命名、结构化命名和惯例命名三种CSS代码命名技巧.     

土壤肥料学实验课程的教学改革与实践

为全面培育卓越农林人才，提高教学培养质量，本研究结合土壤肥料学的课程内容、教学特点及实验方法，对存在的问题进行了剖析，并结合实际针对存在问题做出了相应改革，适时调整《土壤肥料学》实验课程内容和形式。通过删减验证性实验内容，增设综合性实验，传统部分教学内容实现网络化等三方面对该课程的实验课部分进行了改革与实践，以期提高学生综合运用所学《土壤肥料学》的相关知识来解决生产实际问题的能力。     

时标轴上二阶Dirichlet边值问题的弱解（英文）

采用变分方法和临界点理论研究一个时标轴上二阶Dirichlet边值问题弱解的存在性.     

Constructing and evaluating core inflation measures from component‐level inflation data

This paper undertakes a comprehensive examination of 10 measures of core inflation and evaluates which measure produces the best forecast of headline inflation out‐of‐sample. We use the Personal Consumption Expenditure Price Index as our measure of inflation. We use two sets of components (17 and 50) of the Personal Consumption Expenditure Price Index to construct these core inflation measures and evaluate these measures at the three time horizons (6, 12 and 24 months) most relevant for monetary policy decisions. The best measure of core inflation for both sets of components and over all time horizons uses weights based on the first principal component of the disaggregated (component‐level) prices. Interestingly, the results vary by the number of components used; when more components are used the weights based on the persistence of each component is statistically equivalent to the weights generated by the first principal component. However, those forecasts using the persistence of 50 components are statistically worse than those generated using the first principal component of 17 components. The statistical superiority of the principal component method is due to the fact that it extracts (in the first principal component) the common source of variation in the component level prices that accurately describes trend inflation over the next 6–24 months.     

城市治理首要应加强市民的思想道德建设——以湛江市治理交通秩序为例

交通混乱既影响城市形象,又制约经济发展。本文通过对湛江市区交通混乱现象进行深入调查研究,认为要从根本上改变这一现状,取得长效成果,除了采取行政立法、经济处罚、改善交通基础设施等治理措施外,还应着重加强市民的道德建设,提高其思想道德素质,培养市民良好的社会道德行为习惯。文章旨在为加强湛江市民道德建设,解决湛江及其它城市突出交通问题提供参考。     

青藏铁路含保温夹层路基厚度与地温关系的研究

通过对青藏铁路风火山段含有保温夹层的路基建立均匀介质分层纯导热模型并运用分层近似解法求出冻土表层的温度函数,结合Lachenbruch给出的冻土层的理论温度表达式,得到了路基填料层、保温层、地表年平均温度与正弦变化温度的振幅比三者之间的隐式方程,并应用该方程对三者之间的关系进行了分析.