Digestive enzyme activities in mudskipper Boleophthalmus pectinirostris and Chinese black sleeper Bostrichthys sinensis

The mudskipper Boleophthalmus pectinirostris and Chinese black sleeper Bostrichthys sinensis occupy the intertidal zone. However, both species have their own unique diet. The former is an herbivore and the latter is a carnivore. In order to reveal the relationship between digestive enzyme activities and diets in the two species, the activities of protease (P), non-specific bile salt-activated lipase (BAL) and α-amylase (A) were determined in the stomach and intestine of adult mudskipper B. pectinirostris and Chinese black sleeper B. sinensis. The results showed that the activities of protease, BAL and α-amylase in the intestine of B. pectinirostris were significantly (P<0.05) higher than those in the stomach. In B. sinensis, gastric protease activity was not different from the intestinal protease (P>0.05), while BAL and α-amylase activities of the intestine were significantly (P<0.05) higher than those of the stomach. The activity of gastric protease in B. sinensis was significantly (P<0.05) higher than that in B. pectinirostris, while the activities of intestinal protease were not different between the two fish species (P>0.05). BAL activities of the stomach and intestine in B. sinensis were significantly (P<0.05) higher than those in B. pectinirostris, while α-amylase activities of the stomach and intestine in B. pectinirostris were significantly (P<0.05) higher than those in B. sinensis. The ratios of P/BAL, A/P and A/BAL of the digestive tract in B. pectinirostris were 1.5, 107.3 and 158.6, respectively; and those in B. sinensis were 0.2, 1.6 and 0.2, respectively. It can be concluded that food digestion in the adult B. pectinirostris is mainly carried out in the intestine, whereas in the adult B. sinensis it is initiated in the stomach and finishes in the intestine. The activities of BAL and α-amylase in B. pectinirostris and B. sinensis are well correlated with their diets. However, a clear-cut correlation between protease activity and diets is not found in these two species.     

基于离散元数值模拟的四川薛城南沟滑坡形成机制分析

根据南沟滑坡的地质背景及堆积体工程地质特征,结合离散元数值模拟技术,分析南沟滑坡的失稳类型及其成因机制。研究得出如下结论:(1)地震波在经过地形效应放大后,斜坡滑源区竖直峰值加速度PGA最大放大5.1倍,水平峰值加速度PGA最大放大3.97倍。(2)运用离散元数值模拟技术,验证了该斜坡体在地震力作用下的滑坡类型为拉裂—溃滑型。(3)在强震作用下,地震波在坡体内不连续结构面处会发生透射和反射现象,从而导致岩体沿层面发生震动溃裂破坏,形成潜在统一滑面,并伴随有坡体的松弛、甚至解体;在强震持续作用下,坡体沿滑面产生整体的溃滑,形成滑坡。     

大西洋热带海域长鳍金枪鱼渔场预报模型的比较

为提高大西洋热带海域长鳍金枪鱼(Thunnus alalunga)渔场预报的准确率,对K最近邻(k nearest neighbor,KNN)、逻辑斯蒂回归(logistic regression,LR)、决策与分类树(classfication and regression tree,CART)、梯度提升决策树(gr...     

二、利用小行星的观测以决定微星星表的常数

利用太阳及大行星的观测来决定星表系统的经典方法,已不能适合于现代星表及基本系统所提出的要求了。日间的及具有圆盤形的天体的观测,伴随着特殊的系统误差,这些误差,都将引入观测的结果,星表中去。小行星具有和恒星一样的外形,可以如恒星一样的来观测它,是决定星表系统差最适宜的天体。     

区域构造对开滦矿区东欢坨矿煤系的控制作用

从东欢坨矿区域构造特征及构造演化出发,分析了区域地质构造对煤层赋存状况、矿井地质构造展布及构造类型等诸多方面的控制作用。研究表明,该区自石炭-二叠纪成煤后,经历了多期次不同方向的挤压,构造形迹主要形成于燕山期。燕山早期的北东向褶皱控制了区域性煤系的展布,矿井地质构造以断裂为主,主体展布方向为NE—SW向。根据矿区实际,认为应以研究区域地质构造及演化为着眼点,进行相应的地质预测预报工作。     

对地域文化与核心—外围模型参数结合的探索

不少学者探究文化研究与经济学、经济地理学研究的关系,但是关于地域文化如何影响空间集聚的讨论还不够深入。本文选择克鲁格曼的核心—外围模型（CP模型）,采用经济学常规的模型逻辑演绎方法,辅助文献论据,探讨地域文化如何与该模型结合,从而参与解释产业集聚的过程。主要结论为：① 地域文化不但可以影响CP模型中的τ,也可以影响μ和ρ。文化地理学者只有开展区域文化的比较研究,才能将地域文化转变为CP模型中的参数,从而理解文化对区域经济差异的影响。② 根据CP模型的(i, j)地点,提出了适用于CP模型的地域文化单元。在无法将地域文化定量为绝对值的情况下,可以考虑以相对值来定量化,从而支撑聚集趋势分析,但不能支撑集聚准确强度的分析。③ 地域文化研究与CP模型的关联无法揭示区域不均衡发展关系的本质,亦不能唤起人们对文化霸权、拜物教、异化的警觉。因此文化地理学在与经济地理学结合的同时,还有自己独立的学术目标。     

祁连山积雪卫星监测与河西地区河流融雪径流特征分析

现已初步查明河西地区地表水资源为68.80亿立方米。就目前耕地面积和近期的发展来说,河西水资源是够用的。但河西地表水资源时空分布不平衡是造成目前缺水局面的主要原因,而春旱(4—6月)则是发展河西农业生产的主要障碍之一。河西地区河流春汛虽不十分明显且变化大,但其作用不可忽视,素有“春水贵如油”