On the Structural Link Between Variables in Kriging with External Drift

Kriging with external drift allows one to estimate a target variable, accounting for a densely sampled auxiliary variable. Contrary to cokriging, kriging with external drift does not make explicit the structural link between target variable and auxiliary variable, for the latter is considered to be deterministic. In this paper, we show that kriging with external drift assumes implicitly an absence of spatial dependence between the auxiliary variable and the residual of the linear regression of target variable on auxiliary variable at same point. This is the simple model with orthogonal residual, where cokriging is collocated and coincides with kriging of the residual. In this model, the cross-structure is proportional to the structure of the auxiliary variable, and the linear regression of target variable on auxiliary variable does not depend on the support.     

Scum in Nutrient Removal Plants: The Role of Carbon Sources in “Microthrix parvicella” Growth

Scum formation is a widespread problem in activated sludge nutrient removal plants. It often comes along with an excessive development of the filamentous bacterium “Microthrix parvicella” stabilizing the flotation process. As “M. parvicella” was found to depend on long‐chain fatty acids (LCFA) as sole carbon source not only in vitro but also in situ, some options of in‐situ substrate supply are discussed. Wastewater concentrations of fatty acids in the range of 2 to 15 mg L^‐1 and homologue concentrations from synthetic surfactant degradation below 10 mg L^‐1 rule out these substrates as source for excessive biomass production. They might, however, well be suitable for start‐up of a “M. parvicella” population. Build‐up of excessive biomass might rely on fatty acid supply originating in cell walls of lysed stationary phase bacteria of long residence time sludge fractions such as scum layers. Moreover, biogenic surfactants such as rhamnolipids have been proved to be an excellent carbon source for excessive biomass production in vitro.     

Entropy in Markov chains and discrimination of cyclic patterns in lithologic successions

The concept of Markov chains, applied to stratigraphic sections, is reliable in analyzing cyclic patterns in lithologic successions. Randomness in the occurrence of lithologies repeating in a succession is evaluated generally in terms of entropies which can be calculated for the Markov matrix equated with the succession. Two types of entropies pertain to every state; one is relevant to the Markov matrix expressing the upward transitions, and the other, relevant to the matrix expressing the downward transitions. The latter and the former with respect to a certain state, making an entropy set, correspond to the degree of randomness in its linking with the others which occur as the precursor and the successor, respectively. It is obvious that the entropy sets which are calculated for all state variables serve as a reliable criterion in the discrimination of cyclic pattern of the succession. We are able based on the entropy sets to classify the various patterns into asymmetric, symmetric, and random cycles, which are exhibited also in actual lithologic successions. The entropy sets are calculated for Markov matrices which have been reported from a number of areas in the world, and compared with the cyclic patterns supposed there. Entropy for the whole system of sedimentation also is introduced to discuss variability of the condition in the depositional processes.     

区域多尺度马尔可夫随机场的遥感影像分类

多尺度分析技术广泛应用于高分辨率遥感影像的特征提取和建模。分解层数受制于影像的大小,下采样小波变换实现的影像多尺度表达难以描述大范围的空间模式,导致分类结果出现"胡椒盐"现象;面向对象的影像分析技术虽避免了"胡椒盐"现象,但由于仅利用了单尺度的的特征,也难以描述影像多层次的空间模式,导致分类精度较低。为改善分类结果中的"胡椒盐"现象和提高分类精度,提出了一种结合区域多尺度遥感影像分割和马尔可夫随机场的分类方法。首先,获得原始影像过分割区域,依据区域内亮度均值以及区域间的共享边界长度信息,提取影像低频和高频特征,采用该低频特征波段代替原始影像,重复分割与特征波段提取过程,形成影像的区域多尺度表达。然后,以原始图像为初始尺度,以分割区域为处理单元,以更细尺度分类结果为标记场先验,以当前高频特征建立特征场,逐层分类、投影,获得最终尺度分类结果。合成纹理影像和多光谱遥感影像的实验表明:相比于小波域多尺度建模方法和单尺度区域建模方法,本文提出的方法可以有效提高分类精度,并避免"胡椒盐"现象的产生。     

A method for determining the reversibility of a Markov sequence

This paper describes, given a tally matrix with strictly positive entries, a method to determine whether the associated Markov process is reversible, and (for reversible Markov processes) methods to compute the reversibility matrix from the tally matrix. If the tally matrixN is symmetric, then it is shown that the Markov process must be reversible and the reversibility matrixC equalss (R ^–1NR^–1), whereR is the diagonal matrix whosei ^th diagonal entry is the sum of the entries of thei ^th row ofN (for everyi) ands denotes the sum of all the entries ofN. Because a symmetric tally matrix is of special importance in applications, a ² test is proposed for determining, in the presence of experimental errors, whether such a matrix is symmetric.     

<Emphasis Type="Italic">Steak up to the horns</Emphasis>!

Recent conversations concerning organic food systems have focused on the conventionalization hypothesis, which posits that the organic food sector has become increasingly bifurcated between “historical” players in the organic movement on one side, and on the other by distributors and industrial operators recently arrived in the sector, who practice a more conventionalized form of organic agriculture which is now on the ascendancy. The most prominent explanations for the growth and dominance of a conventionalized organic food system have been economic, based in the logics of input costs, especially land rent. We use the cases of the Belgian Blue commodity system and the Belgian organic beef commodity system to argue that conventionalization is also cognitive. To understand the role of cognition in the ascendance of the conventional organic food sector, we utilize concept of “référentiel”—or system of cognitive references—as developed by Muller and Jobert. We believe that comparing organic and conventional practices as two systems of cognitive references makes a deeper understanding of conventionalization possible in two ways: first because it makes it clear that the two systems coexist on a cognitive level, understood in a broad sense as tightly knit sets of knowledges, beliefs, standards, and images. Secondly, the concept of référentiel enables one to understand how the conventional system can become irreversible (lock-in effect) and thus incompatible with the development of the organic system.

郯庐断裂在胶东金矿聚集区的成矿效应

郯庐断裂带是中生代华北与扬子板块的碰撞造山带的陆内转换断层,大规模左行韧性剪切位移牵引胶北太古宙穹隆(栖霞复背斜)逆时针旋扭隆升,并且形成三山岛一仓上、焦家一黄县和招远一平度(破头青)等弧形右行剪切带和混合花岗岩.早白垩世末期郯庐断裂从韧性向脆性构造域的快速转换,引发招掖变质地体的金矿成矿大爆发,形成胶东独特的金矿床汇聚链.     

黄河流域县域碳排放的时空格局演变及空间效应机制

利用空间面板模型、空间自相关分析和以区域背景与最近邻状况为空间滞后的空间马尔科夫链对2000—2017年黄河流域县域碳排放时空格局与空间效应进行分析,结果表明：① 2000年以来黄河流域碳排放量激增,由山东全域和陕甘宁蒙交界的高值区向外圈层与轴向扩张,形成东高西低碳排放格局;② 存在“俱乐部趋同”现象,高碳排放县集聚于山东全域和陕甘宁蒙交界,低碳排放县集聚于西南部;2000年与2017年对比发现县域碳排放类型稳定性强,较高碳排放变为较低碳排放的县集中在东南部区域,而相反方向转变的县集中在内蒙古;③ 高碳溢出效应与低碳锁定效应是塑造时空格局的重要作用力,前者作用力更强;区域背景增强了“俱乐部趋同”与被包围异常值趋同,作用力强于最近邻状况,不显著区域内碳排放类型转变概率提高。④ 空间面板模型结果显示年轻人口结构、大经济规模、二产为主产业结构、高生活水平和高公共支出促进了碳排放量增加与空间效应作用,其中经济规模与产业结构是重要驱动因素。     

基于投入产出表的中国水资源消耗结构路径分析

为了解各部门在生产链中水资源的具体消耗路径和在消耗路径中所发挥的作用以及维持生产链中水资源消耗的关键部门,论文基于2017年投入产出表和相关气象数据,在农业用水中加入绿水资源消耗量,利用投入产出模型和结构路径分析(structural path analysis, SPA)法分析中国42个部门水资源消耗的总量和结构,以及水资源在生产链中消耗的具体路径。结果表明：① 城镇居民消费和进口的水足迹最高,其次为农村居民消费,大多数水足迹较高的部门,都是以居民消费为主,进口水资源弥补了国内部分生产用水的消耗,但水资源短缺的形势仍然严峻;② 生产链前5个层级的水足迹消耗占比为95%左右,其中部门内部消耗占比最大,水足迹随层级数的增加而下降,水资源反馈循环程度较弱;③ 从部门生产链看,部门内部的水足迹占比最大,部门流入和流出水足迹差值较大,部门之间普遍存在单向依赖特征,关联网络不够稳定;④ 从最终消费角度看,农业部门内部水足迹占比最大,是生产链中重要的衔接结点,多样化的消费需求增加上游部门的水资源压力。研究为调整节水政策和提升水资源配置与管理能力提供了一定的理论基础。     

Study of traditional rural settlements landscape genetic variability in shaanxi province based on accurate-restoration北大核心CSCDCSSCI

Landscape genes of traditional rural settlements are a hotspot of settlements' landscape research. Based on existing research, this study defined the landscape genetic information chain and its hierarchy. The general life-like variation mechanism of landscape genes in traditional rural settlements was also proposed. On these bases, considering the landscape characteristics of traditional rural settlements in Shaanxi Province, the landscape genetic information chains of traditional rural settlements in the province were constructed and the general variation mechanism and characteristics of traditional rural settlements in the province were proposed. A theoretical framework of accurate restoration of the traditional rural settlements' landscape genetic information chain was further put forward. In addition, accurate restoration was applied to the typical settlement with variation in Shaanxi Province as an empirical case. The results verified the necessity and operability of accurate restoration. This research provides some thoughts and methods that are fresh and original for the protection and activation of traditional rural settlements from a landscape genetic perspective. © 2020, Editorial office of PROGRESS IN GEOGRAPHY. All rights reserved.