Rainfall,runoff and sediment transport relations in a mesoscale mountainous catchment: The River Isábena (Ebro basin)

This paper examines the relations between rainfall, runoff and suspended sediment transport in the Isábena basin during a quasi-average hydrological year. The Isábena is a mesoscale river basin that drains a mountainous area comprising patches of highly erodible materials (badlands). The paper includes an analysis of the different hydrological and sedimentary responses of the catchment to a similar rainfall. Thirty-four floods were studied, with a very variable response observed. Runoff coefficients ranged from 0.32% to 33%. The sedimentary response was also highly variable, with maximum suspended sediment concentrations (SSC) oscillating between < 0.1 and 90 g l^− 1 and flood sediment loads varying from 27 to 54,000 t per hydrological event. Most sediment load was concentrated in spring when competent floods occur frequently. Pearson correlation matrix and backward stepwise multiple regression indicate that the hydrological response of the catchment is strongly correlated with total precipitation, event duration, and rainfall of the previous days. Very low correlation was observed with rainfall intensity. The relation between rainfall and sediment transport followed the same trend. Sediment variables (e.g., total load and SSC) were significantly correlated with variables such as total rainfall and rainfall over the previous days, although the significance level was lower in comparison with the runoff related variables. There was again no correlation between sediment variables and rainfall intensity. On-going research in the area suggests that, apart from rainfall, factors such as sediment availability in the badlands and accumulation of sediment in the channels influences the river's sedimentary response. The non-linear hydrosedimentary response is reflected in the wide range of runoff coefficients and sediment loads that have been observed in response to similar amounts of precipitation.     

非硬化路面侵蚀产沙规律野外模拟试验

为了科学治理非硬化路面水土流失,采用野外放水冲刷试验,对非硬化路面侵蚀产沙规律进行了试验研究。结果表明,同一坡度不同放水流量与同一放水流量不同坡度条件下,非硬化路面产沙随时间的变化形式均有3种,分别为平缓型、多峰型和单峰型。对同一路面不同观测断面的产沙量分析发现,产沙量沿坡面的空间变化形式分别为波动式减小、逐渐式减小和先增大后减小。、得出平均含沙量与放水流量呈对数相关,产沙率与放水流量、平均含沙量与坡度、产沙率与坡度均呈直线相关。以期为非硬化路面的水土流失预测和治理提供科学依据。     

多孔介质中多组分反应性溶质运移的研究进展

溶质在多孔介质中的运移,必然受到多组分反应的影响,并且此种情况下能用水动力方程和多组分化学平衡方程进行描述。本文回顾了此研究领域的运移模型、数值模拟、可应用的计算软件和相关的问题,并在此基础上,提出目前土壤多组分反应性溶质运移仍存在的问题。     

微喷灌施肥对三七土壤氮素运移转化试验研究

为探明微喷灌施肥对三七土壤氮素运移转化影响,2017—2020年在泸西县大栗树村三七种植基地设置3个灌水水平0.4FC(W1),0.6FC(W2),0.8FC(W3),4个施肥水平3.20(F1),4.80(F2),6.20(F3)和120.00 kg/ha(F4),CK为对照,共13个处理.研究微喷灌施肥条件下不同灌水及施肥对三七土壤全氮、硝态氮和铵态氮运移转化影响.结果表明:不同灌水施肥全氮质量比随时间增加先增大后减小,硝态氮质量比随时间增加先减小后增大,铵态氮质量比随时间增加逐渐减小,8月W2F3全氮质量比最大,9月W2F4硝态氮质量比最大,6月W2F4铵态氮质量比最大.全氮和铵态氮质量比随土层深度增加逐渐减小,硝态氮质量比随土层深度增加先减小后增大,全氮、硝态氮和铵态氮聚集在土层0~10 cm,W2F3土壤全氮和硝态氮质量比最大,W2F4铵态氮质量比最大.灌水量与硝态氮和铵态氮相关性具有统计学意义(P<0.01),与全氮呈负相关且相关性具有统计学意义(P<0.05),施肥量与硝态氮呈正相关且相关性具有统计学意义(P<0.01),与铵态氮相关性具有统计学意义(P<0.05).该研究明确灌溉施肥可调控酸性红壤土三七氮素运移转化特性,改善农田微生态环境,提高水氮利用效率,为有效防治病虫害提供技术支持和理论依据.     

复杂工况下深海采矿混输泵有限元分析

采用流固耦合及有限元方法对布放和混输等复杂工况下3级深海采矿混输泵进行强度计算,分析了泵内流场分布、转子部件应力应变及临界转速,并进行了500 m级深海采矿混输系统海上试验.结果表明:设计流量下,混输泵的计算扬程为124.30 m,相对误差为0.27%;布放工况时,混输泵最大变形仅为0.365 mm,最大应力为73.971 MPa;混输工况时,泵最大变形为0.315 mm,最大应力为58.86 MPa;转子部件前3阶模态仅沿泵轴方向变形,并未发生扭曲,而后3阶模态呈“S”形扭曲变形;转子部件1阶固有频率对应临界转速为2 476 r/min;海试布放过程中混输泵安全可靠,混输工况下泵稳定运行时长超过57 h,实现了2次24 h连续无故障运行,且矿石颗粒体积浓度达到11.7%.     

Optimizing methods in immunocytochemistry: one laboratory's experience

Abstract: The addition of immunocytochemical staining procedures to a diagnostic cytology service enables greater specificity of interpretation for many common disease conditions, especially neoplastic diseases. However, well‐tested immunohistochemical techniques may require modification for cytologic specimens, and other considerations are necessary when working with air‐dried cells. In this article, we describe our experience in evaluating options for sample transport and handling, and discuss methods for obtaining control cells from a variety of tissues for use in immunocytochemical staining. Important immunocytochemical principles and techniques, including fixation, antigen retrieval, and use of primary and secondary antibodies in manual and automated staining systems are described as used in our laboratory for cytologic specimens. Although we emphasize methods relevant to diagnostic laboratories receiving samples from external clients, the information is also applicable to any laboratory interested in adding or enhancing immunocytochemical services.     

甘草生长素反应因子(ARF)基因家族的鉴定及表达分析

本研究旨在鉴定甘草ARF基因家族并分析其在非生物胁迫下的表达模式。以乌拉尔甘草(Glycyrrhiza uralensis Fisch.)为研究对象,利用生物信息学方法对ARF基因家族进行鉴定,并对其蛋白质理化性质、保守结构域、基因结构、进化关系、顺式作用元件和表达模式分析。鉴定得到10个甘草ARF基因。其蛋白氨基酸序列长度在301~945 aa之间,分子量约为33.07~104.37kDa,等电点为5.93~8.50。亚细胞定位分析显示甘草ARF蛋白均位于细胞核。保守结构域分析显示GuARF蛋白大多包含B3、Auxin_resp和Aux/IAA结构域。基因结构发现外显子数量从6个到22个不等。在甘草ARF基因启动子区还存在5类不同的顺式调控元件。系统进化分析表明甘草ARF蛋白分为3类。转录组数据分析显示,10个GuARF基因在非生物胁迫下具有一定表达特异性。上述结果显示甘草ARF基因家族可能参与多种生物过程,这为进一步研究植物对非生物胁迫的生理和分子反应提供了有价值的信息。     

有水与无水保活运输对大菱鲆生理应激及鱼肉品质的影响

为探究大菱鲆分别在有水及无水条件下运输过程中生理生化指标及肌肉品质的变化,为大菱鲆的保活运输提供参考。将大菱鲆进行暂养、降温、充氧包装后进行模拟运输,并在运输不同时间段取样,检测大菱鲆生理生化指标及肌肉指标。结果显示,模拟运输18 h后,有水运输组和无水运输组中的大菱鲆存活率仍为100%。大菱鲆肌肉中水分含量、粗脂肪、pH、糖原、三磷酸腺苷(ATP)和腺苷酸(AMP)含量显著降低,乳酸和肌苷酸(IMP)含量升高。其中,有水运输组中的大菱鲆AMP含量降低了38.65%,IMP含量增加了29.1%,无水运输组中的大菱鲆AMP含量降低了12.83%,IMP含量增加了28.47%。大菱鲆血液生化指标中,葡萄糖、尿素氮和皮质醇含量显著升高。运输过程后,无水运输组中大菱鲆生理应激及能量代谢指标的变化幅度均小于有水运输处理组中的大菱鲆。此外,低温无水运输组大菱鲆肌肉中呈味核苷酸IMP和AMP含量显著高于有水运输组,表明低温无水运输增加了大菱鲆呈鲜味物质的含量,提高了鱼肉风味。研究表明,低温无水保活技术在活鱼运输中具有广泛的应用前景。     

Using a biophysical model to investigate connectivity between spawning grounds and nursery areas of King George whiting (Sillaginodes punctatus: Perciformes) in South Australia’s gulfs

Many demersal marine fish species depend on a dispersive larval stage that connects geographically discrete sub‐populations. Understanding connectivity between these sub‐populations is necessary to determine stock structure, which identifies the appropriate spatial scale for fishery management. Such connectivity is poorly understood for King George whiting (Sillaginodes punctatus; Perciformes) in South Australia's gulf system, even though spawning grounds and nursery areas are adequately defined. In response to declines in commercial catches and estimated biomass, this study aimed to determine the most important spawning grounds and nursery areas to recruitment, and the connectivity between them. A biophysical model was seeded with particles according to the distribution and density of eggs throughout the spawning area in 2017 and 2018. Despite inter‐annual differences in the origins of particles, dispersal pathways and predicted settlement areas remained consistent between years. Predicted settlement was generally highest to nursery areas only short distances from regional spawning grounds, consistent with previous hydrodynamic models. However, the model also predicted that spawning in one region could contribute to recruitment in an adjacent region later in the spawning season, which aligned with the breakdown of thermohaline fronts at the entrance of each gulf. The connectivity between spawning grounds and nursery areas predicted by the model is supported by spatio‐temporal patterns in the otolith chemistry of pre‐flexion larvae and settled juveniles. Consequently, the most parsimonious explanation is that the populations of King George whiting in South Australia's gulf system constitute a single, panmictic stock, which has implications for fishery management.     

土地利用/覆被变化下流域泥沙输移的分形特征及尺度转换

基于由WEPP模型提取的甘肃天水罗玉沟和吕二沟小流域单元侵蚀产沙及泥沙输移资料,采用分形维数理论,对流域泥沙输移比的空间分异规律、泥沙输移比的影响因子以及泥沙输移的尺度转换进行研究。结果表明:年均泥沙输移比有相当大的变幅,不同流域尺度上的泥沙输移比为0.03～1.00,对于一定尺度的流域,泥沙输移比是一个比较稳定的值;小流域泥沙输移过程具有分形特征;根据研究区流域泥沙输移比的分形特征,综合其他地区的研究结果,建立了小流域泥沙输移比尺度转换模型,同时建立了研究区适用尺度范围更广的流域泥沙输移比尺度转换模型。