不同饵料对植食性海水鱼——黄斑蓝子鱼的内脏器官特性及消化酶活性的影响

黄斑蓝子鱼（Siganus canaliculatus）是可养殖的少数植食性海水鱼之一。为进一步了解黄斑蓝子鱼的消化生理特征,以及将海藻更科学地应用于配合饲料中,本研究采用不同类型饵料：冰鲜杂鱼（Raw fish,RF）、配方饲料（Formulated diet,FD）、浒苔（Enteromorpha prolifra,EP）和龙须菜（Gracilaria lemaneiformis,GL）饲喂黄斑篮子鱼8周,分析鱼内脏特征及其消化酶活性的变化情况。研究结果显示：RF组和FD组鱼的肝体比和脏体比,以及EP组和GL组鱼的肠长比（Relative intestine length,RIL）,都显著高于其他组。此外,分析不同处理组鱼的肝和前肠组织形态结构,发现RF组肝细胞核被脂滴挤到细胞边缘,两海藻组前肠黏膜的皱褶程度最高。养殖前三周,鱼的消化酶活性变化波动明显,而之后消化酶活性趋于平稳。消化道的蛋白酶,脂肪酶和α-淀粉酶的水平分别随着日粮中蛋白质,脂肪和碳水化合物水平的变化而变化。虽然,海藻饵料显著降低了黄斑篮子鱼的胃蛋白酶活性,但是提高了机体RIL和前肠黏膜的皱褶程度以弥补其对胃蛋白酶的负面影响。以上结果表明黄斑蓝子鱼的消化系统可较好地适应不同类型的饵料,其适应时间大约为三周。因此,本研究结果也暗示黄斑蓝子鱼也具有一些杂食性鱼类的属性。     

脐带缆螺旋滑移分析及力学性能研究

针对脐带缆内部螺旋层,应用Darboux标架建立螺旋结构空间坐标系,推导弯曲载荷下螺旋结构的局部变形和滑移。考虑螺旋构件间的接触和摩擦作用,建立螺旋结构的受力平衡偏微分方程,并研究螺旋角和摩擦系数对螺旋结构滑移的影响。基于同层螺旋结构本构关系相同假设,将所有螺旋结构力学性能线性叠加,拟合脐带缆整体弯曲刚度。运用建立的理论解析方法,对某双层铠装脐带缆的力学性能进行研究,并与数值模拟结果进行对比验证。对比结果表明,理论解析得到的螺旋滑移结果与数值模拟结果一致,理论解析得到的脐带缆弯曲刚度与数值模拟结果在全滑动阶段比较接近。     

基于遥感视反射率图像的矿化信息识别及其应用

成矿作用过程中产生的矿化蚀变,在遥感图像上往往是一种非直接的弱相关信息。文章以川西西支沟地区为例,通过典型矿床地面波谱分析,并在视反射率图像模拟及其与典型矿床地面波谱反射率的相关分析基础上,对矿化蚀变信息进行反演识别研究。西支沟地区的研究表明,基于视反射率图像的矿化信息反演识别分析可增强遥感图像矿化信息,在多金属矿化信息识别方面有较理想的找矿预测效果。     

Structural, electronic and optical properties of orthorhombic distorted perovskite TbMnO3

This paper calculates the structural parameters, electronic and optical properties of orthorhombic distorted perovskite-type TbMnO₃ by first principles using density functional theory within the generalised gradient approximation. The calculated equilibrium lattice constants are in a reasonable agreement with theoretical and experimental data. The energy band structure, density of states and partial density of states of elements are obtained. Band structures show that TbMnO₃ is an indirect band gap between the O 2p states and Mn 3d states, and the band gap is of 0.48 eV agreeing with experimental result. Furthermore, the optical properties, including the dielectric function, absorption coefficient, optical reflectivity, refractive index and energy loss spectrum are calculated and analysed, showing that the TbMnO₃ is a promising dielectric material.     

The economics of ending Canada's commercial harp seal hunt

The roots of the Canadian harp seal hunt can be traced to the 16th Century. But in the mid-20th century, opposition to the commercial hunt became widespread after television images of seal pups being killed with clubs on the pack ice off the coast of Newfoundland were broadcast around the world. International conservation groups, animal welfare groups, animal rights groups, and foreign governments have been calling for the Canadian government to end the commercial seal hunt on the grounds that it is inhumane and that harvest levels are unsustainable. The Canadian government defends the traditional practices of hunting harp seals, argues that seal pelts are an important source of income for sealers, and insists that the killing methods are humane and that harvest levels are sustainable. Emotions run high on both sides of the debate. The purpose of this paper is to evaluate whether or not there is a purely economic argument for ending Canada's commercial seal hunt. The paper finds that the benefits of ending the commercial hunt exceed the costs, but not unequivocally. However, the paper argues there should be a higher criterion—the Pareto criterion—for ending the commercial hunt; that is the hunt should end only if winners compensate the losers. The paper goes on to argue that an effective way to satisfy this criterion is to introduce a system of individual transferable quotas (ITQs) and let the market reveal the value of the commercial seal hunt. In addition to many other advantages such as improving the safety and efficiency of the hunt, the ITQ market could provide a mechanism by which those willing to pay to end the hunt could do so directly to sealers thereby ensuring that the hunt is scaled back or ultimately ended only when it is economically efficient and unambiguously welfare-improving.     

石油污染对黄河口沉积物工程性质的影响

对黄河口胜利油田某油井附近沉积物进行石油污染状况调查研究,采用坑探试验现场调查污染范围,发现油井沉积物在一定范围内存在石油污染,污染多在0.2～1.5 m深度内,水平距离在140～440 m之间.原位测试污染沉积物强度,取样进行室内石油浓度和沉积物物理力学指标测试.石油污染沉积物物理力学性质与未污染的有较大差别,污染后沉积物的重度、渗透系数和强度等均有所降低.污染后的沉积物结构,多成块状和板状结构.     

和田玉的鉴定与评估

新疆和田玉是世界软玉品种中最好的一种,有“玉王”之称。该文对和田玉的矿物组成、化学成分及物理性质进行了鉴定分析,提出了和田玉原料及玉器的评估方法。     

鲤鱼（Cyprinuscarpio L．）体重和体长QTL的定位

利用265个AFLP标记、127个微卫星分子标记、37个EST-SSR标记和16个RAPD标记（共445个标记）对大头鲤／荷包红鲤抗寒品系的F2代雌核发育群体44个个体进行基因型检测,构建鲤鱼（CyprinuscarpioL.）遗传连锁图谱;利用软件WinQTLCart2.5采用复合区间作图法对体重和体长两个性状进行了QTL定位分析。结果共检测到与两个与体重性状相关的QTL,分别定位到LG24连锁群（qBWh-24-1）和LG20连锁群（qBWh-20-1）上,可解释的表型变异分别为7.98％和20.05％;检测到两个与体长性状相关的QTL,分别位于LG2连锁群（qFS-2-1）和LG20连锁群（qFS-20-1）,可解释的表型变异分别为5.69％和12.69％,4个QTL的加性效应均为负值。     

草鱼、鲤鱼肠道、肝胰脏消化酶活性的初步研究

用两种不同蛋白质和糖类水平的饲料喂养草鱼、鲤鱼夏花及一龄鱼种，通过对两种鱼肝胰脏及肠道的消化酶活性测定发现，在一定温度条件下，随着水温升高，两种鱼肠道及肝胰脏的蛋白酶和淀粉酶比活均升高；鱼类摄食后六小时酶比活明显大于摄食后二十四小时的酶比活，在水温２５℃条件下，用两种不同饲料分别饲养草鱼、鲤鱼六周后发现：随着饲料蛋白质水平的提高，草鱼、鲤鱼肝胰脏中蛋白酶比活明显升高鲤，而总肠变化不显著；随饲料中糖量水平的提高，草鱼肝胰脏及肠道的淀粉酶比活明显升高，而鲤鱼差异不显著．草鱼，鲤鱼肠道蛋白酶比活以后肠最高，中肠次之，前肠最小。而肠道淀粉酶比活性却随饲料成分而发生差异。两种鱼肝胰脏消化酶活性均为一龄鱼种大于夏花阶段，这与组织切片的观察结果相符。     

QOCA和GLOBK软件处理高精度GNSS网结果对比分析

分别利用GLOBK和QOCA软件对陆态网络260个基准站的GNSS观测数据进行处理,获得站点在ITRF2008框架下的坐标和速度。通过比较分析两个软件的解算结果,证明了QOCA 软件能更好地处理测站位移的非线性变化,并通过拟合周年、半年项、剔除共模误差等手段提高解算精度。结果表明,相比于GLOBK软件,QOCA软件得到的拟合残差序列的RMS在E、N、U 3个方向上分别减小70%、80%和70%。