Time Variation of Cosmic and Quantum Masses in Dirac’s Cosmology

It is shown that the expressions of five fundamental masses appearing in physics and cosmology can be written in terms of the constants of nature. We study the time variation of them in the context of a generalized Dirac’s cosmology based on the large number hypothesis (LNH). This generalization allows one to have the gravitational constant not depending upon time contrary to Dirac’s original theory. It also allows the rest mass of the particle to vary with cosmological time. Further, we show that there exist simple algebraic relations between them and that their ratios can be expressed as powers of the large dimensionless number 10⁴⁰.     

Development of a modelling methodology for the investigation of riparian hydrological processes

The riparian zone is in intimate contact with the river and, as such, is a critical zone for understanding hydrological problems. This paper presents a general modelling methodology for the assessment of riparian hydrological processes. It is applicable to a wide range of riparian spaces and incorporates current expertise in numerical methods. A core part of the modelling methodology is the random walk particle method (RWPM). We develop an RWPM as part of the ESTEL2D subsurface flow model, test it against analytical solutions and apply it to the simulation of parcels of water as they move through the riparian zone. The modelling methodology provides a new opportunity to assess fundamental hydrological process issues such as the proportioning of pre‐event and event water storm runoff, and reversals of flow in floodplains. Copyright © 2005 John Wiley & Sons, Ltd.     

Relationship of minimum winter temperature and temperature seasonality to the northern range limit and species richness of trees in North America

Biologists have considered both winter coldness and temperature seasonality as major determinants of the northern limits of plants and animals in the Northern Hemisphere,which in turn drive the well-known latitudinal diversity gradient.However,few studies have tested which of the two climate variables is the primary determinant.In this study,we assess whether winter coldness or temperature seasonality is more strongly associated with the northern latitudinal limits of tree species and with tree species richness in North Amedca.Tree species were recorded in each of 1198 quadrats of 110 km × 110 km in North America.We used correlation and regression analyses to assess the relationship of the latitude of the northern boundary of each species,and of species richness per quadrat,with winter coldness and temperature seasonality.Species richness was analyzed within 38 longitudinal,i.e.,north-south,bands (each being ＞1100 km long and 110 km wide).The latitudes of the north-ern range limits of tree species were three times better correlated with minimum temperatures at those latitudes than with temperature seasonality.On average,minimum temperature and temperature seasonality together explained 81.5％ of the variation in the northern range limits of the tree species examined,and minimum temperature uniquely explained six-fold (33.7％versus 5.8％) more of this variation than did temperature seasonality.Correlations of tree species richness with minimum temperatures were stronger than correlations with tempera-ture seasonality for most of the longitudinal bands analyzed.Compared to temperature sea-sonality,winter coldness is more strongly associated with species distributions at high lati-tudes,and is likely a more important driver of the latitudinal diversity gradient.     

Models as multiple working hypotheses: hydrological simulation of tropical alpine wetlands

Tropical alpine grasslands, locally known as páramos, are the water towers of the northern Andes. They are an essential water source for drinking water, irrigation schemes and hydropower plants. But despite their high socio‐economic relevance, their hydrological processes are very poorly understood. Since environmental change, ranging from small scale land‐use changes to global climate change, is expected to have a strong impact on the hydrological behaviour, a better understanding and hydrological prediction are urgently needed. In this paper, we apply a set of nine hydrological models of different complexity to a small, well monitored upland catchment in the Ecuadorian Andes. The models represent different hypotheses on the hydrological functioning of the páramo ecosystem at catchment scale. Interpretation of the results of the model prediction and uncertainty analysis of the model parameters reveals important insights in the evapotranspiration, surface runoff generation and base flow in the páramo. However, problems with boundary conditions, particularly spatial variability of precipitation, pose serious constraints on the differentiation between model representations. Copyright © 2010 John Wiley & Sons, Ltd.     

动态导航定位噪声相关性的实时探测处理

提出了探测噪声相关性的图解法,直观地确定噪声的相关程度;基于统计检验的思想设计零假设,并构造检验统计量,给出了探测相关性的假设检验法。结果表明,图解法和假设检验法均能有效地判断噪声的相关性,实用中可将两种方法相结合,以达到最佳效果。     

射电天文台址常驻电磁干扰检测与识别方法

为有效统计射电天文台址常驻电磁干扰的变化,提高实时电磁环境监测效率,提出一种基于先验信息的常驻电磁干扰信号检测与识别方法.首先通过信噪分离,信号能量估值从电磁环境历史监测数据中提取移动通信,地面数字电视等常驻大信号的中心频率、极化方式、来波方向等特征,经对无线信号传播信道的衰落方式进行分析,提出信号能量模型服从的分布函数假设并采用K-S检验验证该假设,合理设置能量阈值,建立信号模板库.其次,根据信号模板库中的信号特征对实时频谱数据进行双门限能量检测、信号相关性识别,从而提高信号检验的准确率,实现了常驻信号的快速统计.针对射电天文台址实测频谱,运用该方法能够有效识别并统计频谱中的常驻信号,从而为台址干扰缓解策略制定提供重要依据.     

Comparison of thematic maps using symbolic entropy

Comparison of thematic maps is an important task in a number of disciplines. Map comparison has traditionally been conducted using cell-by-cell agreement indicators. More recently, other methods have been proposed that take into account not only spatially coincident cells in two maps, but also their surroundings or the spatial structure of their differences. The objective of this article is to propose a framework for map comparison that considers (1) the patterns of spatial association in two maps, in other words, the map elements in their surroundings; (2) the equivalence of those patterns; and (3) the independence of patterns between maps. Two new statistics for the spatial analysis of qualitative data are introduced that are based on the symbolic entropy of the maps. As well, all inferential elements to conduct hypothesis testing are developed. The framework is illustrated using real and simulated maps.     

MASS WASTING IN THE SWAUK WATERSHED,WASHINGTON

Mass wasting evidence is common along the margins of the Columbia River Basalts. I identified, mapped, dated, and assessed the environment of nearly 160 discrete slope failures (excluding rockfall) along the margins of the Columbia River Basalts in the Swauk watershed of central Washington. Rotational slides, translational slides, flows, and complex slide-flows were identified via topographic map, airphoto, and field analysis. Geographic information systems analysis revealed that these features cover 38% of the watershed. Translational slides are the most numerous of the slope failures, whereas complex slide-flows cover the most area. I placed each slope failure into a relative age category (active, inactive-young, inactive mature, and inactive-old) based on the characteristics of the main scarp, lateral flanks, internal morphology, vegetation cover, and toe relationships. Most Swauk watershed slope failures are inactive-mature. Organic sediments from an inactive-mature sag pond formed ～6880 ¹⁴C yr BP, whereas inactive-young sediments dated at ～5930 ¹⁴C yr BP. Inactive slope failures are often associated with steep slopes, inclined beds, incompetent geologic units, or streamcuts. Streamcuts, roadcuts, or clearcuts typically accompany active slope failures. Rain-on-snow events and associated mass wasting in winter 1996 provide a plausible trigger analog for inactive mass wasting. Rockfall deposits cover ～29% of the watershed, range from inactive to active in age, and occur atop pre-existing slope failures in well-jointed Columbia River Basalts. Mass wasting has played a key role in shaping the topographic and hydrologic patterns of the watershed. [Key words: mass wasting, watershed, Washington state, Columbia River Basalts, rain-onsnow.]     

基于Car(p,q)模型和数学形态学理论的LiDAR点云数据滤波

在分析现有的LiDAR点云数据后处理方法的基础上,本文提出了一种点云数据“分步”滤波方法。首先对LiDAR点云数据进行数学形态学“粗”滤波,得到“地面点假设”和“非地面点假设”。然后引入顾及因果关系的自回归模型（car）对两类点云数据假设进行模型化处理和假设检验,根据假设检验的结果判断地面点和非地面点,最终得到可靠的分类结果。与单纯的“最小二乘拟合预测法”或“数学形态学”方法相比,这种“分步”处理的思想用于LiDAR点云数据分类处理的结果更可靠。     

植物护理效应研究综述

植物护理效应是指护理植物在其自身冠幅下辅助目标植物生长发育的现象.近年来,植物护理效应被应用于世界范围内多数的退化生态系统的修复与重建.文章综述了当前植物护理效应的主流研究内容主要为护理植物的确定、影响其效应的因素、形成其效应的原因与机理以及护理、竞争及胁迫梯度假说,归纳了样方调查、种子萌发实验、幼苗栽植实验等研究方法,总结了其与生态位、系统发育、全球变化等相关生态学概念的关系,指出未来对植物护理效应的研究不应仅仅局限于中观尺度上,在微观尺度上(目标植物对护理效应的生态适应性的激素效应与分子机制)和宏观尺