Natural and Anthropic Middle-term Variations in the Delta System at the Mouth of the Goro River (Po Delta, Italy)

Abstract. The modern delta system of the Po River is the result of an evolution strictly controlled by anthropic factors and mainly developed during a period of climatic deterioration (Little Ice Age 1550/1850).
At the beginning of the 17^th century the main branch of the Po River, Fornaci Po, was modified with the "Cut of Viro" in order to avoid landfill of the Venetian Lagoon. Simultaneously, the southernmost branch of Ariano, or Goro, was forced to flow southwards. Subsequent sedimentary variations, caused by changes in the climatic conditions, contributed to make the area supplied by the Goro Po River increasingly lagoonary. In the second half of the 19^th century (end of the Little Ice Age – L.I.A. –), the first coastal spits started to take shape and developed in different systems throughout the entire following century. Coastal spits turned out to produce in the original bay, a progressive closure towards the sea. The strong decrease in solid loads, characterising the second half of the 20^th century and mainly due to anthropic factors, marks the beginning of a new phase extending to the overall Po Delta system, in which the mouth layout is controlled by wave energy.     

Morphological and Biological Particularities of Black Sea Whiting Merlangius merlangus euxinus (nordmann) (Teleostei: Gadidae)*

Abstract. From 1987–1992 nearly 4000 specimens of Merlangius merlangus euxinus were collected from most Black Sea areas. Biological parameters such as weight, standard length, sex, and age were studied. Seven meristic and twenty-four morphometric parameters were analyzed from 756 specimens. Data were processed employing discriminant and cluster analyses; they indicate the existence of several populations or sub-populations of the Black Sea whiting. The findings are supported by biological data and the general circulation pattern of the Black Sea.     

Stability of tidal inlets—Pass Cavallo,Texas

Many tidal inlets are scoured in loose granular material, and the morphological changes in these inlets are discussed. The changes are the result of the predominantly fortnightly variations in the tide, the seasonal variations in storm activity and the occurrence of extreme meteorological events. The adjustment of an inlet to changes in the hydraulic environment and sudden changes in its morphology associated with extreme meteorological events is primarily via a change in the cross-sectional area. For a single-inlet bay system, the response of the inlet cross-sectional area can be determined using the stability analysis presented by Escoffier (1940). Rather than one inlet, many bays are connected to the ocean by several inlets. In this study, Escoffier's analysis is expanded to include the interaction of these inlets. In the analysis, the sediment carrying capacity of the inlet currents is characterized by the bottom shear stress. The stability analysis is applied to Pass Cavallo, Texas. Assuming the absence of future influences of tropical storms and hurricanes, the analysis shows that as a result of the opening of a companion inlet, Pass Cavallo ultimately will close.     

四种两性生殖卤虫雄性抱持器的形态比较

对四种卤虫:A.franciscana,A.sinica,A.persimilis,A.tunisiana的雄性抱持器及其额结节进行比较观察。在额结节表面有两种突起。树突和感觉毛。两者的排列和分布复杂,在不同种卤虫之间,它们的差别很明显。据此,额结节辅以抱持器的形态大小可作为卤虫的鉴定的重要标志。四种卤虫的简易鉴定法:1.A.franciscana额结节小,约150μm,抱持器粗壮,与其粗短体形一致。其体宽体长比值为0.17。2.A.sinica额结节小,约150μm,抱持器纤细,与其细长体形一致,其体宽体长比值为0.10。3.A.persimilis额结节大,半圆形,直径约350μm,抱持器端节前沿呈弧形。4.A.tunisiana额结节大,圆锥形,高350μm,抱持器端节前沿呈拐角突起。     

Investigation of the morphology of pore space in mudstones—first results

A suite of selected Tertiary mudstones was studied to improve the knowledge about microstructure and related transport processes in mudstones. Samples were investigated by mercury- and Wood's metal injection, SEM, XRD, and grain size analysis. Wood's metal injection has the advantage of visualising the ‘frozen’ injection process. The smallest pore casts observed were down to 40 nm in diameter, while the largest, bottle-shaped pores were up to 5 μm in diameter. Bottle-shaped pores occurred in all the samples, usually around silt or sand grains. One sample, which had a porosity of 28.5% according to mercury injection data, had not been impregnated by the molten alloy. We suggest this to reflect a strong deformation of the clay fabric by the high pressure without intrusion into the matrix. This raises questions about the reliability of mercury injection data for very fine-grained, highly porous sediments.After excluding these very fine-grained samples and one very calcareous sample regressions were found which relate porosity (φ), clay content (C), and sand content (S) to capillary displacement pressure (P_d(Hg)): P_d(Hg)=−25.05+0.63 C+0.29S (R²=0.92), and P_d(Hg)=−10.24+0.47 C−0.15φ (R²=0.88).     

赤鼻棱鳀松果体显微结构研究

本文用组织学方法研究了赤鼻棱鳀（Thrissapurava）松果体的形态结构，结果表明赤鼻棱鳀有松果体窗，并有发达的松果体，感光细胞聚集成团，顶突伸入终囊腔中，终囊类型为折褶型。背囊由单层细胞构成，细胞大而圆，松果体司感光内分泌功能。     

数理统计学方法在中国水产资源研究中的应用概述

数理统计学方法对于水产资源学的发展发挥了极其重要的推动作用。数理统计方法在中国水产资源学的应用．起步于50年代．发展于60到80年代，90年代以后进入了一个崭新的发展阶段。作为一个发展中国家，同世界其他国家相比．我们将面临着更多的机遇与挑战。     

数学形态学方法在海面船目标检测中的应用

为进一步提高检测精度，提出1种将数学形态学方法应用到船目标检测数据后处理中的算法，根据该算法设计的数学形态学滤波器可以有效地消除SAR图像斑点噪声在船目标检测中造成的影响，减少船目标检测的误判，提高参数估计准确性。     

三门湾多个围垦工程的整体影响数学模型研究

海湾内的围垦工程对潮流及冲淤都将产生影响.以三门湾蛇蟠和下洋涂围垦工程为例,设计了3组试验对比的数值模拟计算方案,对比计算结果表明,预测三门湾内2个围垦工程对水动力环境产生的影响,当讨论单一围垦工程时,应把工程前的海湾状态设置为湾内没有任何其它工程,这样才能得出单个围垦工程对湾内环境的真实影响;当讨论2个围垦工程对水动力环境产生影响时,应进行2个围垦工程整体数学模拟计算,考虑2个围垦工程的叠加累积影响,并与海湾原始状态(即假定海湾在围垦前湾内没有任何其它围垦工程)进行比较,才能得出较为科学的预测结果.     

AUV Local Path Planning Based on Acoustic Image Processing

The forward-looking image sonar is a necessary vision device for Autonomous Underwater Vehicles （AUV）. Based on the acoustic image received from forward-looking image sonar, AUV local path is planned. When the environment model is made to adapt to local path planning, an iterative algorithm of binary conversion is used for image segmentation. Raw data of the acoustic image, which were received from serial port, are processed. By the use of ＂Mathematic Morphology＂ to filter noise, a mathematic model of environment for local path planning is established after coordinate transformation. The optimal path is searched by the distant transmission （Dt） algorithm. Simulation is conducted for the analysis of the algorithm. Experiment on the sea proves it reliable.