Racialized Identitites and the Formation of Black Gangs in Los Angeles

This article traces the history of Black gangs in Los Angeles, California and identifies the factors that were most significant in the formation of these gangs during two waves of gang formation in the post-World War II period. The results of this analysis suggest that the racialization of Black youths played a major factor in both waves of gang formation. The more popular explanations based on economic and community deficiencies, themselves a by-product of racialization, are more central to gang maintenance and proliferation than gang formation.     

Environmental research of groundwater in the urban and suburban areas of Attica region,Greece

In this study, 92 groundwater samples were collected from the Attica region (Greece). Moreover, geographical information system database, geochemistry of groundwater samples and statistics were applied. These were used for studying the chemical parameters (NO₃ ⁻, Mg²⁺, Ca²⁺, Cl⁻, and Na⁺) and conductivity spatial distribution and for assessing their environmental impact. The ranges of chemical parameters of the water samples (in mg L⁻¹) are: NO₃ ⁻ 1–306, Mg²⁺ 2–293, Ca²⁺ 3–453, Cl⁻ 5–1,988, and Na⁺ 4–475. The elevated concentrations of sodium, Mg²⁺, Cl⁻ are attributed to natural contamination (seawater intrusion). On the other hand, NO₃ ⁻ elevated concentrations are attributed to anthropogenic contamination (nitrate fertilizers). The results of the GIS analysis showed that elevated values of Na⁺, Mg²⁺, Cl⁻ are related to shrubby and sparsely vegetated areas, while elevated values of NO₃ ⁻ are connected with urban and agricultural areas.     

就业郊区化背景下郊区就业者日常活动时空间特征研究——以北京上地地区为例

个体日常活动时空间特征反映了其对城市空间利用的时空需求,是衡量社会服务、公共资源配置的新维度。基于个体行为分析郊区就业者日常生活时空间特征,有利于透视郊区就业者的空间需求以及就业郊区化带来的城市空间变革。利用2012年北京市活动出行调查数据,选取居住在北京郊区且在上地地区(郊区)工作的203个就业者样本,从非汇总角度对该群体日常活动时空间特征进行描述分析,揭示郊区就业者日常活动的时空需求。研究结果发现,郊区就业者在休息日的活动呈现较强的时间碎片化与空间分散性特征;郊区就业者对中心城区存在较强的空间依赖,很大一部分休闲购物活动需要前往中心城区发生,同时郊区大型商业设施也一定程度上吸引了郊区就业者,郊区功能趋向复合化;郊区就业空间职能较为单一,公共和商业设施供给不足,利用率较低,需进一步完善。     

Aptian–Albian Cupressaceae (sensu stricto) woods from Cañadón Asfalto Basin,Patagonia Argentina

This paper describes the first macrofloristic record from Los Adobes Formation (Chubut Group) in Cañadón Asfalto Basin (Patagonia, Chubut Province, Argentina). The studied fossils were recovered from the Aptian–Albian Bardas Coloradas Member, and consist of silicified woods preserved in fluvial channel deposits. One wood shows homocellular rays with smooth radial and tangential walls, diffuse axial parenchyma, tracheid pitting of the abietinoid type and cross-field pitting cupressoid usually ordered in rows and columns indicating placement within Cupressinoxylon hallei Kräusel. This fossil tree resembles some members of the extant Cupressaceae s.s., as Austrocedrus chilensis (D. Don) Pic. Serm. & Bizzarri, Pilgerodendron uviferum (D. Don) Florin, Fitzroya cupressoide (Molina) I. M. Johnst. and Libocedrus plumosa (D. Don) Druce. Due to poor preservation the other fossil wood specimen was assigned to cf. Cupressinoxylon Göppert 1850 nom. cons. prop. This is the first unequivocal record of C. hallei from the Cretaceous of South America and the oldest reliable record of the Callitroideae, indicating that this subfamily was well established since the mid-Cretaceous in the Southern Hemisphere.     

The suburban bias of American society?

Past research has characterized countries as displaying the traits of urban or rural bias. Neither concept fits the United States well. We propose, as a hypothesis for research, that it may better be understood as displaying a suburban bias vis-à-vis both urban and rural populations. Drawing on the urban and rural bias literatures, we discuss two forms that suburban bias might take, allocational and dispositional, and the ways in which they might be identified. We offer initial evidence of a prevailing suburban bias in the United States in two spheres, those of judicial interpretation and American planning history, and conclude with suggestions for further research on the hypothesis.     

Analysis of the hydrological behaviour of an urbanizing basin

Suburban areas undergo rapid land‐use changes due to urban growth. Consequently, the mitigation of hydrological impacts is a major issue in the field of flood and water pollution management. Nevertheless, suburban catchments have seldom been studied. This paper presents a method for analyzing the hydrological behaviour of suburban catchments; the particular method is tested on the Chézine catchment, located in a suburban area of Nantes (western France). Chézine provides a typical example of a suburban catchment, yet features the unique behaviour of a response time ranging from 1 to 6 h. It is proposed herein to classify rainfall‐runoff events in homogeneous groups according to their flow coefficient. A group of events is characterized by its mean flow coefficient and by its transfer function, which are considered as the signatures of the hydrological behaviour of these similar events. The transfer function is identified from the available series of rainfall and outflow data. The identified transfer functions serve to estimate the localization of contributing zones over the basin by estimating the basin transfer function from flowpaths. The consistency of these assumptions is then verified by comparing the estimated transfer function with the identified one. The application of this method to the Chézine catchment demonstrates that it is possible to distinguish various types of hydrological behaviour regimes associated with significantly different transfer functions. The joint analysis of the flow coefficient and transfer function of each group confirms that the Chézine catchment reacts like an urban basin with just the urban zones contributing to runoff under dry conditions. Otherwise, the wetter the initial state, the greater the tendency of this basin to react like a natural basin, as reflected by the different transfer function shapes. These results confirm the validity of the proposed method to analyse the various behaviour regimes of suburban catchments. In addition, this method helps define the specifications of hydrological models suited to suburban catchments. Copyright © 2013 John Wiley & Sons, Ltd.     

The influence of foliation on the fragility of granitic rocks, image analysis and quantitative microscopy

Fabric-dependent anisotropy is important in understanding the mechanical behaviour of foliated rocks because the foliation creates mechanically weak discontinuities. Using optical microscopy, a foliation index (FIX) was calculated for a group of granitic rocks in southern Sweden that displays a range of textures from foliated to nonfoliated. Image analysis from scanning electron microscope with backscattered detector (SEM/BSE) images was used in order to measure the rock texture of these samples. The analyses were compared with the Los Angeles (LA) test, which measures resistance of rock aggregate to fragmentation. The results demonstrate that the measured grain size, shape and spatial arrangement are important parameters controlling the fragility of the rock. Both the texture and foliation must be taken into account to obtain a significant relationship with the mechanical analyses. We suggest that this alternative method could be a helpful tool for predicting a rock's suitability as an aggregate as it gives a better understanding of the material properties compared to mechanical testing.     

Chemical Composition and Association of Size-Differentiated Aerosols at a Suburban Site in a Semi-Arid Tract of India

Size-differentiated concentrations of SPM, F, Cl, NO₃, SO₄, Na, K, Ca, Mg and NH₄ in atmospheric aerosols were measured in a suburban area of Agra city during December 1992 to March 1993. Except for NH₄, Cl and Na, all components were found to have a bimodal distribution. The fine fraction was dominated by NH₄, K, NO₃ and SO₄, while Na, Ca, Mg, F and Cl contributed to the coarse fraction. Fifty-eight percent of SO₄ and 67% of NO₃ were found in the fine mode and the coarse mode comprised 42 and 33% of SO₄ and NO₃, respectively. SO₄ was found to have a peak above the submicron range at 1.1 µm which has been attributed to secondary sulphate formation by heterogeneous oxidation of SO₂ on alkaline particles of Ca and Mg. The total aerosol was basic in nature and dominated by the soil-derived acid neutralising components (Ca, Mg and Na).     

小城镇空间结构变迁的形式和动力

小城镇向心增长的空间过程主要表现为郊区城镇化、内城更新改造、反向扩展3种形式，是小城镇对农村人流、物流的集聚和内部空间结构的优化。小城镇离心增长的空间过程主要表现为城镇郊区化、产业区位变迁、外向扩展3种形式，是小城镇生产力发展到一定阶段后城镇要素向近郊区的扩散。小城镇向心增长和离心增长是集聚与扩散相互作用的表现，社会经济发展是小城镇空间变迁的根本动力，功能－形态互适机制是其演变的主要机制。