壳寡糖对吉富罗非鱼幼鱼生长性能、非特异性免疫及血液学指标的影响

用添加质量分数0.00(对照组)、0.10%、0.30%、0.50%和0.70%壳寡糖的饲料饲喂初始体重(3.81±0.23)g的吉富罗非鱼幼鱼(Oreochromis niloticus)10周,研究不同浓度壳寡糖的添加对吉富罗非鱼幼鱼的生长、非特异性免疫功能以及血脂指标的影响。结果表明:与对照组相比,在4个不同浓度添加组中,添加质量分数0.50%壳寡糖能显著提高幼鱼的增重率(P<0.05)、特定生长率(P<0.05),并降低饲料系数(P<0.05);添加质量分数0.3%和0.5%壳寡糖能显著提高幼鱼抗嗜水气单胞菌感染的能力(P<0.01);添加质量分数0.10%、0.30%、0.50%壳寡糖能显著提高幼鱼血清中碱性磷酸酶活性(P<0.05)。同时,各浓度的壳寡糖均能明显提高幼鱼血清中溶菌酶和超氧化物歧化酶活性以及抗嗜水气单胞菌感染的能力(P<0.05),并降低幼鱼血清中总胆固醇和低密度脂蛋白胆固醇水平(P<0.05)。在本实验条件下,添加壳寡糖可提高吉富罗非鱼幼鱼生长性能、饲料利用率、非特异性免疫功能和调节血脂水平,添加量以质量分数0.30%~0.50%为宜。     

Genealogy of the Singaporean black‐and‐white house

The distinctive black‐and‐white houses from Singapore's colonial era that survive in enclaves as fine dwellings for the present‐day elite have been recognized and documented as a type. In this paper we tell the story of their cultural formation, which is one of remarkable hybridity. Various influences were brought to bear and resolved into the black‐and‐white house‐type, which was not invented ‘all at once’ in Singapore, but developed over the course of more than two centuries. We begin the story in India, when British settlers learnt from local Bengali practices to make serviceable dwellings for a climate that they found difficult. The overhanging roofs that shaded walls and the tall internal volumes were formalized with reference to European expectations of geometry and finish, and the bungalow was born. In British Malaya the bungalow was further hybridized with the house on stilts that was well known to the indigenous tradition. This produced the spatial configuration that is to be found also in the Singapore houses, with their extensive verandas on an upper floor level. Their distinctive colouring comes from a different tradition: the black‐and‐white Tudoresque style that was very popular in Britain and sometimes called ‘Old English’. This was used by the British colonizers so that they could feel more at home in surroundings that were in a far‐off foreign cultural environment.     

庐山JL剖面红土磁化率特征及古环境记录

江西九江庐山地区JL剖面红土磁化率测试结果表明:1.典型网纹红土的磁化率远小于弱网纹红土和棕黄色黄土-古土壤,数值上,棕黄色黄土-古土壤是网纹红土的2.33倍.剖面各层段频率磁化率均值变化于10.09％～ 13.71％,且与磁化率显著正相关,表明风化成土作用中形成的超顺磁性颗粒对红土磁性增强具有重要贡献.2.湿润气候和土壤渍水的假潜育环境下铁磁性矿物易于分解、转化、淋失,这可能是导致网纹红土磁化率异常偏小的主因.从而在剖面上磁化率与CIA变化趋势相反,两者峰谷波动又基本一致.3.结合ESR年代,JL红土磁化率沿剖面自下而上分为4个波动式增大的阶段,可与早更新世以来季风环流演变过程中的几个重要转折期对应,记录了大尺度内的古环境变化信息.早更新世以来该区环境湿润程度波动式减弱,气候自中更新世以来由湿热向干冷转变.     

On the diet of Nile tilapia in two eutrophic tropical lakes containing toxin producing cyanobacteria

Due to the production of toxins, cyanobacteria may adversely affect economically important fish such as Nile tilapia Oreochromis niloticus in tropical lakes. We studied the diet composition and factors affecting the diet of Nile tilapia in two tropical lakes where cyanotoxins were present. Particle-bound microcystins were present in all analysed water samples, ranging in concentration from 0.00012 to 1.11 and from 0.006 to 0.254 μg L⁻¹ in Murchison Bay in Lake Victoria and Lake Mburo, respectively. Detritus and phytoplankton were the main dietary components of the Nile tilapia, with phytoplankton contributing to over 30% by volume of stomach contents. The cyanobacteria Microcystis spp., which are also the most likely source of microcystins in the lakes, accounted for more than 80% of ingested phytoplankton. Microcystis spp. were also the most abundant cyanobacteria in both lakes (>60%). We found no significant relationship between the contribution of phytoplankton in Nile tilapia diet and the concentration of microcystins in the water but we found a close association between water transparency and the contribution of insects to Nile tilapia diets in Murchison Bay. Our results further show that none of the other measured environmental variables was a good predictor of diet items in Nile tilapia. Adult Nile tilapia in our study lakes, rely heavily on filter feeding, particularly under conditions of low water transparency, trapping detritus and phytoplankton cells especially colonies. They can ingest more mobile prey like insects and insect larvae when the water transparency and visibility increases.     

Degradation of Reactive Brilliant Red X‐3B Dye by Microwave Electrodeless UV Irradiation

Degradations of reactive brilliant red X‐3B solution by both conventional UV irradiation and microwave electrodeless UV irradiation were investigated. Degradation processes were studied by UV–VIS spectrophotometry, total organic carbon (TOC), high performance capillary electrophoresis (HPCE), conductivity, pH value, and ion chromatography. The results of color removal (%) and TOC removal (%) showed that the degradation by microwave electrodeless UV irradiation was more effective than by conventional UV irradiation. The results of UV–VIS absorption spectra and HPCE analyses indicated that the degradation of reactive brilliant red X‐3B was occurred at the conjugation system first, the benzene ring and the naphthalene ring later. The reactive brilliant red X‐3B was cleaved into some new small compounds and eventually most of the organic substances were mineralized to CO₂ and H₂O. The results of the conductivity analysis suggested that the degradation has mainly occurred in the first 40 min of reaction. The pH value of reactive brilliant red X‐3B solution was decreased first and then was increased. The results of inorganic anions analysis hinted that many of the N, Cl, and S elements from reactive brilliant red X‐3B were still attached in organic molecules.     

非饱和红黏土的不排气、不排水三轴剪切试验研究

非饱和土中由于有孔隙气的存在而使得非饱和土的力学性质变得非常复杂。气体对非饱和土体强度和变形会产生重要影响。根据12组不同饱和度、不同干密度云南红黏土土样的三轴不排气、不排水剪切试验结果,讨论了气体对非饱和土土体强度和变形的影响。黏聚力在不排气剪切情况下随着饱和度的变化不是单调的,内摩擦角则随着饱和度的增大而减小。干密度增大则黏聚力和内摩擦角都增大。在三轴不排气剪切过程中,试样出现了明显了的剪胀性,且随着干密度的减小,饱和度的增大剪胀性逐渐消失。试样最后的破坏形态与是否发生剪胀可能也有联系。     

红层小流域地区储水单元水文地质特征研究

根据四川红层小流域地区地形地貌特征,将典型红层小流域地区地下水储水单元模式划分为河谷阶地储水单元、宽缓沟谷储水单元、低中山储水单元。各类储水单元在地形地貌、地层岩性、风化状况、构造部位、水文地质条件等因素控制下,具有不同水文地质特征。     

LED单色光谱及复合光谱对赤潮优势种中肋骨条藻生长的作用

以赤潮优势种中肋骨条藻(Skeletonema costatum)为研究对象,荧光灯和自制LED(light-emitting diode)控制灯为光源,研究不同LED单色光谱及复合光谱(蓝光,绿光,红光,白光,蓝红光,绿红光)对中肋骨条藻生长的作用。实验结果表明,在相同的光合有效量子通量密度条件下,对于单色光,中肋骨条藻在蓝光下生长较快,红光次之,在绿光下生长最慢;对于复合光,中肋骨条藻在荧光灯下生长最快,而在蓝红光下生长略高于在绿红光下生长。各光源下中肋骨条藻生长速率的顺序为:荧光灯>蓝红光LED>绿红光LED>蓝光LED>红光LED>绿光LED。通过比较在不同光照条件下中肋骨条藻的生长速率,表明不同光谱对中肋骨条藻生长的作用不同。     

热带产卡拉胶海藻形态及表皮特征比较

2008 年6 月至2009 年6 月, 在山东青岛实验室和海南陵水试验平台, 以光学显微镜及电子扫描显微镜等技术, 对12 种原产印度尼西亚和菲律宾热带产胶红藻外观形态, 表皮细胞特征进行了比较。结果表明:1)不同株系藻体呈现褐色、绿色、黄绿色、翡翠绿色、橄榄绿色和咖啡色等多样性; 2)在表皮细胞特性方面, 5 号株系细胞最小、排列最致密、分布最均匀, 8 号株系细胞最大、胞间距最宽; 3)在亚显微结构方面, 1 号藻呈均一球状突起, 2 和4 号藻为不规则突起, 3、6 和9 号藻表面布满酒窝样凹陷, 5和8 号藻表面比较平整, 7 和11 号藻呈脑纹状褶皱, 12 号藻在凹凸结构外覆盖鳞片状白色胶质; 4)在实验株中, 1、2 和4 号藻未发现四分孢子, 3、5、6、11 和12 号藻表皮细胞上具有结构对称的四分孢子, 且主要分布于较老的主干上; 5)在四分孢子排列上, 3、5、11 和12 号四分孢子间排列紧密, 6 号藻四分孢子间距离较远; 6)不同藻的四分孢子囊大小形态存在明显差异, 6 号藻株四分孢子囊最长, 约110 μm, 5号藻四分孢子囊最短, 约40 μm, 3、11、12 号藻四分孢子囊长约60 μm, 四分孢子囊宽度相对恒定, 除5 号藻较窄约为10 μm 外, 其他株系均约为15 μm。     

邵阳市区红粘土特征与环境工程地质问题

红粘土系碳酸盐岩的红土化残坡积物，具有独特的结构构造和物理力学性质，并具裂隙发育较强的收缩性，与基岩接触处往往可见土洞存在。人类在红粘土区进行工程－经济活动时，往往引起国坡失稳，地面塌陷，水土流失等环境工程地质问题，本文分析了这些问题产生的原因，提出了防治措施。