Size trends and population characteristics of striped marlin,Tetrapturus audax caught in the New Zealand recreational fishery

Size trends and population characteristics of striped marlin, Tetrapturus audax, caught in the New Zealand recreational fishery were evaluated using club records from the Bay of Islands Sword‐fish Club (BOISC) from 1925 to 2003 (n = 15 114) and biological samples from northern New Zealand collected from 1985 to 1994 (n = 684). Average weight (kg) ± SE of striped marlin declined 6–9 kg every 20 years between 1925 (124.2 ± 1.0 kg) and 2003 (100.1 kg ± 0.4). Weight (H14843 = 444.58, P < 0.001) and condition (H443 = 37.54, P < 0.001) increased significantly throughout the recreational fishing season (December‐May). No differences were observed in the lower jaw‐fork length (LJFL)‐weight (W) relationship between sexes or years but average weight of females (106.2 ±1.1 kg) was significantly greater than males (90.2 ±1.2 kg) from 1985 to 1994 (F684 = 88.37, P < 0.001). Negative allometric growth (W = 2E ‐08 LJFL^2.88) was recorded for all striped marlin. Individual growth was modelled by fitting backcalculated LJFL to eight age classes derived from dorsal spine measurements (n = 94) using the von Bertalanffy growth equation (r² = 0.96). The parameters estimated in the von Bertalanffy growth equation were asymptotic length (L ) = 3010 mm, annual growth rate (K) = 0.22, age (yr) at hypothetical length 0 (t0) = ‐0.04.     

F子夜均值逐日差空间异常变化与地震的关系研究

利用2010年1月1日至2014年4月30日我国地磁台网100多个台站的地磁总强度F子夜均值数据,逐一分析了F子夜均值逐日差的空间变化趋势。结果表明,在此期间有18次小区域的异常变化,其中16次异常与其后几天到半年时间内该区域发生的地震有很好的对应关系,另外两次新近的异常有待后续进一步验证。我国西北部地区地磁台站稀疏,布局不合理,限制了对新疆、青海、西藏等地震多发区震磁关系的研究,建议这些地区进一步加密台站建设,优化布局。     

安徽省新石器和夏商周时代遗址时空分布与人地关系的初步研究

安徽省新石器早期遗址有淮北的小山口和江南的沟汀,该时期淮河流域的聚落多于长江流域。新石器中期,考古发掘的野生动物骨骼和孢粉分析表明聚落周围是一个河湖密布、森林草原并存的生态环境。新石器晚期,古人已能分辨土壤的优劣并很可能会利用环境条件改善土壤的不良特性;蒙城尉迟寺遗址的剖面分析表明,环境只是古聚落分布和数量变化的基础因素,生产力的因素也在起作用,因为长时间的持续降温和夏初的大洪水侵袭。夏商周时期全省聚落总数增加,但淮北平原因为长时间的持续降温和夏初的大洪水侵袭,聚落大规模缩减。皖中和皖南的丘陵山地地貌使那里所受洪灾较轻,灾后这些地区因热量条件好使聚落迅速发展起来。新聚落大多建在利于农业生产、能躲避洪水的地方。     

A comparative study of nonlinear Markov chain models for conditional simulation of multinomial classes from regular samples

Simulating fields of categorical geospatial variables from samples is crucial for many purposes, such as spatial uncertainty assessment of natural resources distributions. However, effectively simulating complex categorical variables (i.e., multinomial classes) is difficult because of their nonlinearity and complex interclass relationships. The existing pure Markov chain approach for simulating multinomial classes has an apparent deficiency—underestimation of small classes, which largely impacts the usefulness of the approach. The Markov chain random field (MCRF) theory recently proposed supports theoretically sound multi-dimensional Markov chain models. This paper conducts a comparative study between a MCRF model and the previous Markov chain model for simulating multinomial classes to demonstrate that the MCRF model effectively solves the small-class underestimation problem. Simulated results show that the MCRF model fairly produces all classes, generates simulated patterns imitative of the original, and effectively reproduces input transiograms in realizations. Occurrence probability maps are estimated to visualize the spatial uncertainty associated with each class and the optimal prediction map. It is concluded that the MCRF model provides a practically efficient estimator for simulating multinomial classes from grid samples.     

环渤海地区城镇化与农村协调发展的时空特征

城镇化是区域发展的必然趋势,探究城镇化过程中农村发展响应对于理解城乡关系、区域城镇化以及农村发展具有重要的指导意义。本文着力构建城镇化与农村发展评价指标体系以揭示环渤海地区城镇化与农村发展时空格局,并探究二者的协调特征。结果表明:1环渤海地区城镇化与农村发展均存在明显的空间差异,二者高低值空间分布不完全吻合,农村发展差距整体上小于城镇化差距;2城镇化能在一定程度上推动农村发展,但随着城镇化水平提升,二者协调程度下降,农村发展分异加大;3协调分析需要紧密结合城镇化与农村发展状态,三者空间分布存在多种耦合情形。认为新型城镇化背景下,统筹城乡发展需要着力打破城乡二元管理体制,创新城镇化与农村发展协调机制;应着力凸显地域主体功能,加强不同功能区间的协同;宜依托区域自身禀赋特征,探索契合当地特色的城镇化道路。     

Hydrodynamic interactions and relative motions of two floating platforms with mooring lines in side-by-side offloading operation

The hydrodynamic interaction and mechanical coupling effects of two floating platforms connected by elastic lines are investigated by using a time-domain multi-hull/mooring/riser coupled dynamics analysis program. Particular attention is paid to the contribution of off-diagonal hydrodynamic interaction terms on the relative motions during side-by-side offloading operation. In this regard, the exact method (CMM: combined matrix method) including all the vessel and line dynamics, and the 12×12 hydrodynamic coefficients in a combined matrix is developed. The performance of two typical approximation methods (NHI/No Hydrodynamic Interaction: iteration method between two vessels without considering hydrodynamic interaction effects; SMM/Separated Matrix Method: iteration method between two vessels with partially considering hydrodynamic interaction effects, i.e. ignoring off-diagonal cross-coupling terms in the 12×12 hydrodynamic coefficient matrix) is also tested for the same side-by-side offloading operation in two different environmental conditions. The numerical examples show that there exists significant discrepancy at sway and roll modes between the exact and the approximation methods, which means that the cross-coupling (off-diagonal block) terms of the full hydrodynamic coefficient matrix play an important role in the case of side-by-side offloading operation. Therefore, such approximation methods should be used with care. The fender reaction forces, which exhibit large force with contact but no force without contact, are also numerically modeled in the present time-domain simulation study.     

一种新的基于Gabor小波的非监督纹理分割方法

提出了一种新的基于Gabor小波的非监督纹理分割方法,与传统Gabor方法相比,该方法最大的特点在于分割的过程中利用了纹理尺度之间的依存关系和像素之间的空间约束关系。为了克服增加特征所带来的"维数灾难"问题,用独立分量分析(ICA)进行特征的整合。采用Brodatz测试集的实验结果验证了方法的有效性。     

平面应变下原状黄土的剪切带研究

针对黄土地区工程建设中的平面应变问题,使用改进的西安理工大学真三轴仪进行了不同侧向固结压力、不同含水率下原状黄土的平面应变剪切试验,得出了剪切破坏时剪切带倾角试验值,根据应力-应变关系曲线求出了剪切带倾角的Mohr-Coulomb、Roscoe理论解,分析了相应控制因素下原状黄土强度、剪切带破坏模式与倾角的变化。结果表明：应力-应变曲线随含水率、侧向固结压力的增大从原生软化型向次生硬化型转变;剪切带破坏模式随侧向固结压力的增大依次呈现单一剪切带、锥型剪切带和X型剪切带;随着含水率的增大,黏聚力、内摩擦角减小导致Mohr-Coulomb剪切带倾角减小,剪胀作用增强导致Roscoe剪切带倾角增大;随侧向固结压力增大,动内摩擦角增大及剪胀作用增强,导致Mohr-Coulomb、Roscoe剪切带倾角增大。     

Trace Element Abundance Relationships in the Multi—stage Comagmatic Fractional Crystallization and Their Applications

In this study a mathematical expression of trace element abundance relationship for the mul-ti-stage comagmatic fractional crystallization has been established ,based on geochemical studies of the Emeishan basalt-trachyte series and adjacent mafic-ultramafic layered intrusions, as well as on the avail-able data for basalt, andesite, dacite and rhyolite series in southern Andes,Chile ,which have been well documented.It is demonstrated that the abundance constant (R) for a given trace element at dif-ferent stages of fractional crystallization of a parental magma is highly variable,which can be used as a criterion to divide fractional crystallization stages.     

多中心城市中山市职住空间关系特征

以低密度多中心城市——中山市为例,采取政府主导的居民出行调查数据库中40445 个调查样本,应用ArcGIS 等分析工具,利用居民出行调查数据库中的个体属性与职住地点等信息,对居民职住比、通勤时间、通勤距离和通勤方向进行可视化,分析中山居民的职住空间关系格局。结果表明：职住比、通勤时间、通勤距离在空间上有一定的区域差异,但圈层结构均不明显。全市职住空间分布整体较均匀,主城区职住基本平衡;周边镇区尤其是西北组团、东部组团职住比高,而主城区较低。全市平均通勤时间和通勤距离均显著低于国内大城市和发达国家城市。主城区和外围镇区间的通勤量及其比重小,全市没有产生大规模的外围―中心“钟摆式”通勤,在通勤方向上更多表现为内―内通勤和外―外通勤。居民的职住关系空间分布特征与城市空间结构、人口结构、产业结构与产业布局、土地利用以及交通设施建设具有密切的关系,低密度多中心的城市职住平衡程度高、通勤时间和通勤距离均较短,而主城区与外围镇区通勤联系不紧密。