Modelling mussel growth in ecosystems with low suspended matter loads using a Dynamic Energy Budget approach

The environmental and the economic importance of shellfish stimulated a great deal of studies on their physiology over the last decades, with many attempts to model their growth. The first models developed to simulate bivalve growth were predominantly based on the Scope For Growth (SFG) paradigm. In the last years there has been a shift towards the Dynamic Energy Budget (DEB) paradigm. The general objective of this work is contributing to the evaluation of different approaches to simulate bivalve growth in low seston waters by: (i) implementing a model to simulate mussel growth in low suspended matter ecosystems based on the DEB theory (Kooijman, S.A.L.M., 2000. Dynamic and energy mass budgets in biological systems, Cambridge University Press); (ii) comparing and discussing different approaches to simulate feeding processes, in the light of recently published works both on experimental physiology and physiology modeling; (iii) comparing and discussing results obtained with a model based on EMMY (Scholten and Smaal, 1998). The model implemented allowed to successfully simulate mussel feeding and shell length growth in two different Galician Rias. Obtained results together with literature data suggest that modeling of bivalve feeding should incorporate physiologic feed-backs related with food digestibility. In spite of considerable advances in bivalve modeling a number of issues is yet to be resolved, with emphasis on the way food sources are represented and feeding processes formulated.     

基于RAGA的PPC模型在化探异常分析中的应用——以凤太矿集区为例

化探数据处理的核心内容是地球化学背景与地球化学异常的合理区分,找矿信息提取将直接影响到成矿预测的结果.文章采用基于RAGA的PPC模型对凤太矿集区1:5万水系沉积物化探数据进行处理,初步探讨了投影寻踪聚类方法在地球化学异常识别与元素共生组合方面的应用,以及投影方向值所代表的地质意义.结果表明,PPC模型的化探异常识别效...     

中国大陆精密重力潮汐改正模型

利用理论和实验重力固体潮模型,充分考虑全球海潮和中国近海潮汐的负荷效应,建立了中国大陆的精密重力潮汐改正模型.结果表明,采用不同的固体潮模型会对重力潮汐结果产生相对变化幅度小于0.06％的差异;在沿海地区海潮负荷的影响约为整个潮汐的4％,而中部地区约为1％,其中中国近海潮汐模型的影响约占整个海潮负荷的10%,内插或外推潮波的负荷约占海潮负荷的3％.通过比较实测的重力数据表明,本文给出的重力潮汐改正模型的精度远远优于0.5×10^-8 m·s^-2,说明了本文构建的模型的实用性,可为中国大陆高精度重力测量提供有效参考和精密的改正模型.     

Neural network modelling of planform geometry of headland-bay beaches

The shoreline of beaches in the lee of coastal salients or man-made structures, usually known as headland-bay beaches, has a distinctive curvature; wave fronts curve as a result of wave diffraction at the headland and in turn cause the shoreline to bend. The ensuing curved planform is of great interest both as a peculiar landform and in the context of engineering projects in which it is necessary to predict how a coastal structure will affect the sandy shoreline in its lee. A number of empirical models have been put forward, each based on a specific equation. A novel approach, based on the application of artificial neural networks, is presented in this work. Unlike the conventional method, no particular equation of the planform is embedded in the model. Instead, it is the model itself that learns about the problem from a series of examples of headland-bay beaches (the training set) and thereafter applies this self-acquired knowledge to other cases (the test set) for validation. Twenty-three headland-bay beaches from around the world were selected, of which sixteen and seven make up the training and test sets, respectively. As there is no well-developed theory for deciding upon the most convenient neural network architecture to deal with a particular data set, an experimental study was conducted in which ten different architectures with one and two hidden neuron layers and five training algorithms – 50 different options combining network architecture and training algorithm – were compared. Each of these options was implemented, trained and tested in order to find the best-performing approach for modelling the planform of headland-bay beaches. Finally, the selected neural network model was compared with a state-of-the-art planform model and was shown to outperform it.     

“野外地质掌中宝”系统的及其应用

“野外地质掌中宝”系统是以Ｗｉｎｄｏｗｓ ＣＥ为软件平台,以掌上电脑为硬件载体, 适用于野外地质勘探和国土资源调查的便携式工作平台。它包括前端工具软件包、后台伺服处理子外地质勘探和国土资源调查技术的一次重要实践,它的研制成功将为野外地质工作才提供面向２１的高效、实用、方便的现代化工作平台。     

日照豪迈码头港池布局对泥沙输移影响研究

港池的布局会改变其周边海域水动力条件及其泥沙冲淤状况,为了进一步了解其影响程度,本文以山东日照豪迈重工临港厂区运输码头的改造工程为研究对象,利用平面二维数值模型MIKE21/3 Integrated Models,建立了潮流和波浪耦合作用下的泥沙输移数值模型,对该工程附近海域进行了波浪、潮流和泥沙输移的数值模拟。同时采用实测数据对数值模型进行了验证,数值模拟结果与实测资料拟合较好,表明MIKE21能有效地模拟运输码头及其周围海域潮流的变化过程。以日照豪迈重工临港厂区运输码头为依托,基于数值模拟结果,分析不同改造方案下的水动力条件和泥沙冲淤状况。结果表明:港池布局对水动力条件影响甚微,对地形地貌冲淤影响较大;模拟结果确定港池南向开口为最佳改造方案,为工程的规划和设计提供科学依据。     

Alonso's Theory of Movements: Developments in Spatial Interaction Modeling

 The Spatial Interaction Model proposed by Alonso as “Theory of Movements” offers an innovative specification of spatial origin-destination flow models. Equations for flows between regions, total outflow from and total inflow to a region are linked by balancing factors. This paper presents a consistent formulation of Spatial Interaction Models in the Wilson tradition and Alonso's Theory of Movements. The paper is intended as an introduction to the model and a review of␣the state of the art. Besides it is argued that simultaneous equation techniques are required to estimate the so-called systemic parameters. Received: 21 May 2000 / Accepted: 18 January 2001     

Shared Socio-Economic Pathways of the Energy Sector – Quantifying the Narratives

Energy is crucial for supporting basic human needs, development and well-being. The future evolution of the scale and character of the energy system will be fundamentally shaped by socioeconomic conditions and drivers, available energy resources, technologies of energy supply and transformation, and end-use energy demand. However, because energy-related activities are significant sources of greenhouse gas (GHG) emissions and other environmental and social externalities, energy system development will also be influenced by social acceptance and strategic policy choices. All of these uncertainties have important implications for many aspects of economic and environmental sustainability, and climate change in particular. In the Shared-Socioeconomic Pathway (SSP) framework these uncertainties are structured into five narratives, arranged according to the challenges to climate change mitigation and adaptation. In this study we explore future energy sector developments across the five SSPs using Integrated Assessment Models (IAMs), and we also provide summary output and analysis for selected scenarios of global emissions mitigation policies. The mitigation challenge strongly corresponds with global baseline energy sector growth over the 21st century, which varies between 40% and 230% depending on final energy consumer behavior, technological improvements, resource availability and policies. The future baseline CO₂-emission range is even larger, as the most energy-intensive SSP also incorporates a comparatively high share of carbon-intensive fossil fuels, and vice versa. Inter-regional disparities in the SSPs are consistent with the underlying socioeconomic assumptions; these differences are particularly strong in the SSPs with large adaptation challenges, which have little inter-regional convergence in long-term income and final energy demand levels. The scenarios presented do not include feedbacks of climate change on energy sector development. The energy sector SSPs with and without emissions mitigation policies are introduced and analyzed here in order to contribute to future research in climate sciences, mitigation analysis, and studies on impacts, adaptation and vulnerability.     

江淮流域梅雨期气候对全球气候变暖的响应

在全球气候变暖背景下,中国江淮流域梅雨期的气候响应趋于复杂,给江淮流域梅雨期的气候预测带来了更多的不确定因素。研究江淮梅雨期气候对全球变暖的响应,对于认识江淮梅雨变化新趋势、提高新气候背景下的汛期预报及制定防灾减灾政策均有深远意义。采用中国地面气温和降水日值数据集对近几十年来江淮地区梅雨期的气温和降水变化进行了深入分析,基于观测结果,评估了国际耦合模式比较计划第5阶段（CMIP5）的22个模式结果,并对CMIP5模式预估的21世纪中排放（RCP4.5）和高排放（RCP8.5）情景下中国江淮流域梅雨期的气温和降水变化进行了分析,并对梅雨期气候变化的机理进行了探讨。研究结果表明,在全球变暖背景下,江淮地区梅雨期气候亦发生了相应的变化,气温呈现出显著的升高趋势,降水亦发生了相应调整,在较暖年降水偏多,较冷年降水偏少。在未来全球进一步变暖的背景下,江淮地区梅雨期平均气温进一步升高,降水进一步增多,且随着排放量的增加,降水的空间分布不均匀性也在加剧。      

海洋细菌胞外蛋白酶PPC结构域序列特性与系统进化分析

PPC(Pre-Peptidase C-terminal)结构域广泛分布于分泌型海洋细菌蛋白酶的C末端,对蛋白酶的分泌,锚定及与底物相互吸附起到重要作用。对PPC结构域序列分析发现,PPC结构域存在两个较为保守序列区,且这两个保守区空间结构为β-折叠。尽管有的PPC结构域序列一致性较低,但不同结构域间存在相同的保守序列,且其三维结构相似。为了进一步对不同来源的PPC结构域的进化关系进行系统研究,本研究选取公开发表的PPC结构域,通过在NCBI数据库中搜索得到61条来自于39个细菌所分泌的不同蛋白酶的PPC的氨基酸序列进行系统发育分析。发现PPC结构域在生物进化过程中序列变异性大,保守性弱。其中,有些细菌PPC结构域可能来源于自身基因重复产生,有些细菌PPC结构域则可能由水平基因转移产生。