Fractal Reconstruction with Unorganized Geochemical Data

Fractal geometry is receiving increased attention as a model for many natural phenomena. In this paper, we address two issues in dealing with unorganized 3-D measured data using fractal geometry: extraction of fractal characters and fractal surface (geochemical landscapes) reconstruction. We start from a set of randomly measured 3-D data on a plane. After classification and concentration of the input data, we present methods for estimating the fractal dimension and texture deviation as fractal characters, and then an improved subdivision scheme is developed to reconstruct fractal surface on the basis of the extracted fractal characters. We demonstrate both characterization and reconstruction with irregularly measured geochemical data from 1767 stream sediment samples in the middle district (450km² in area) of Zhejiang, China.     

Elemental δ13C at Allen's Cave,Nullarbor Plain,Australia: assessing post‐depositional disturbance and reconstructing past environments

The degree to which post‐depositional disturbance can be assessed in archaeological sequences is critical for the development of robust chronologies for such deposits. A common approach is the identification of conjoined artefacts distributed through the sequence as a measure of disturbance following deposition, although this method is relatively labour intensive and does not provide a continuous record of disturbance through the entire sequence. Here we present δ¹³C values for different size fractions (<125 and >125 µm) of chemically resistant charcoal distributed through a sedimentary profile at Allen's Cave, South Australia. The curves generated from both size fractions parallel one another, indicating minimal disturbance through the entire profile and providing greater confidence in the luminescence and radiocarbon chronologies reported previously for the site. In addition, the elemental δ¹³C values provide an indication of greater aridity (compared with present) persisting in this area from ca. 45 to 12 ka, consistent with other proxy records. The onset of the Holocene is marked by a shift to wetter conditions, probably as a result of post‐glacial marine transgression and closer proximity to the coastline. Copyright © 2001 John Wiley & Sons, Ltd.     

Climatic significance of δ <Superscript>18</Superscript>O records from an 80.36 m ice core in the East Rongbuk Glacier,Mount Qomolangma (Everest)

The δ ¹⁸O variations in an 80.36 m ice core retrieved in the accumulation zone of the East Rongbuk Glacier, Mount Qomolangma (Everest), is not consistent with changes of air temperature from both southern and northern slopes of Himalayas, as well as these of the temperature anomalies over the Northern Hemisphere. The negative relationship between the δ ¹⁸O and the net accumulation records of the ice core suggests the “amount effect” of summer precipitation on the δ ¹⁸O values in the region. Therefore, the δ ¹⁸O records of the East Rongbuk ice core should be a proxy of Indian Summer Monsoon intensity, which shows lower δ ¹⁸O values during strong monsoon phases and higher values during weak phases.     

Relationships Between Fundamental Seismic Hazard Parameters for the Different Source Regions in Turkey

Turkey has been divided into eight different seismic regions taking into consideration the tectonic environments and epicenters of the earthquakes to examine relationships of the modal values (a/b), the expected maximum magnitudes (M_max) and the maximum intensities (I_max). For this purpose, the earthquakes for the time period 1900–1992 from the Global Hypocenter Data Base CD-ROM prepared by USGS, and for the time period 1993–2001 from the PDE data and IRIS data are used. Concerning the relationships developed between different magnitude scales and between surface wave magnitudes (M_S) and intensity for different source regions in Turkey, we have constructed a uniform catalog of M_S. We have estimated the values of M_max and I_max using the Gumbel III asymptotic distribution. Highest a-values are observed in the Aegean region and the lowest b-values are estimated for the North Anatolian Fault. Maximum values of a/b, M_max and I_max are related to the eastern and western part of the North Anatolian Fault and the Aegean Arc. The lowest values of all parameters are observed near the Mid Anatolian Fault system. Linear relationships have been calculated between a/b, M_max and I_max using orthogonal regression. If one of the three parameters is computed, two other parameters can be calculated empirically using these linear relationships. Hazard maps of M_max and I_max values are produced using these relationships for a grid of equally spaced points at 1°. It is observed that the maps produced empirically may be used as a measure of seismic hazard in Turkey.     

Stiffness degradation of natural fine grained soils during cyclic loading

Cyclic behavior of natural fine grained soils under a broad range of strains were investigated considering the effects of plasticity index and changes in confining pressures based on cyclic triaxial tests. A total of 98 stress controlled cyclic triaxial tests were conducted on normally consolidated and slightly overconsolidated samples. The investigation was divided into two parts. The first part consists of stress controlled cyclic triaxial tests under different stress amplitudes that were conducted to estimate the modulus reduction and the thresholds between nonlinear elastic, elasto-plastic and viscoplastic behavior. The second part involves the investigation of the undrained stress–strain behavior of fine grained soils under irregular cyclic loadings. The results showed that the elastic threshold is approximately equal to 90% of G_max. Another transition point was defined as the flow threshold where the value of tangent of shear modulus ratio changes for the second time. Simple empirical relationships to estimate the dynamic shear modulus and damping ratio was formulated and compared with the similar empirical relationships proposed in the literature. The results provide useful guidelines for preliminary estimation of dynamic shear modulus and damping ratio values for fine grained soils based on laboratory tests.     

Effects of Policy Measures and Moderating Factors on Climate Change Adaptation Among Private Forest Owners in Sweden

Threats associated with climate change may damage forests. To encourage adaptation in countries with a lot of privately owned forest, policy measures directed at private forest owners may be implemented. By means of policy scenarios, the present study examined the effects of two hypothetical policies: an advice and an economic incentive, on climate change adaptation among private forest owners in Sweden (n?=?753 and n?=?729). Both policies strengthened the intention to adapt although results also revealed that individual variables (i.e., forest values) and a contextual variable (i.e., being in an encouraging social risk management context) were important for the owners’ response. Production forest values and social risk management context furthermore moderated the effect of policy on intention to adapt, suggesting that the economic incentive was mainly more effective than the advice among owners with strong production values and among owners in less encouraging social risk management contexts.     

沙坝海岸沿岸流速度剖面特征研究

通过对两个坡度沙坝地形沿岸流实验测量和基于能量方程的沿岸流数值模拟,研究了沙坝海岸平均沿岸流速度剖面的双峰剖面特征,重点分析了第二个峰值的特征和两峰值的比值。综合考虑入射波高、入射波类型和坡度对波生沿岸流垂直岸线速度剖面的影响。结果表明,平均沿岸流速度剖面出现双峰剖面特征:第一峰值发生在沙坝向岸侧面的中部,第二个峰值发生在靠近岸线处;同一坡度情况两个峰值的位置和比值,不受入射波类型、入射波高的影响。数值模型中包括了侧混、底摩擦和水滚等因素,其数值模拟结果和实验值拟合较好,并讨论了有无侧混和水滚对速度剖面的影响。     

Urban Forest Values of the Citizenry in Three Colombian Cities

Urban forests are an integral part of urban ecosystems and quality of life. With an overwhelmingly urban population, Latin American countries benefit considerably from their urban forests. However, little is known about the values that make such forests important. The goal of this study was to provide an overview of urban forest values in Colombia. Exploratory research was undertaken in the cities of Bogotá, Cali, and Pereira, with the use of field tours based on visits to five urban forest types, personal diaries, and focus groups. Recruitment was based on voluntary self-selection. Data were captured from 72 participants and analyzed via coding and theme extraction. The data demonstrate that Colombian urban dwellers value the urban forest in terms of a rich array of psychological, aesthetic, sociocultural, ecological, environmental, and economic themes. This study is a primer for eliciting urban forest values and developing typologies in a novel and effective way.     

Experts' Perspectives on the Integration of Indigenous Knowledge and Science in Wet Tropics Natural Resource Management

Aboriginal inhabitants of the Wet Tropics of Queensland advocate for greater inclusion of their Indigenous knowledge (IK) in natural resource management (NRM) to fulfil their customary obligations to country and to exert their Native Title rights. Despite a legal and institutional framework for inclusion of IK in NRM, IK has so far been applied only sporadically. We conducted an ethnographic case study to investigate perceptions on IK, science and how they affect integration of the two knowledge systems in the Wet Tropics. Our results show that IK and science are perceived as different concepts; that integration is limited by weak Indigenous internal and external governance; and that stronger Aboriginal governance and more focused engagement strategies are required to further the application of IK in local NRM. We conclude by arguing that NRM in the Wet Tropics needs to be reconceptualised to accommodate IK holistically, by considering its epistemology and the values and ethic that underpin it.