Children's daily travel to school in Johannesburg-Soweto,South Africa: geography and school choice in the Birth to Twenty cohort study

This paper has two aims: to explore approaches to the measurement of children's daily travel to school in a context of limited geospatial data availability and to provide data regarding school choice and distance travelled to school in Soweto-Johannesburg, South Africa. The paper makes use of data from the Birth to Twenty cohort study (n?=?1428) to explore three different approaches to estimating school choice and travel to school. First, straight-line distance between home and school is calculated. Second, census geography is used to determine whether a child's home and school fall in the same area. Third, distance data are used to determine whether a child attends the nearest school. Each of these approaches highlights a different aspect of mobility, and all provide valuable data. Overall, primary-school-aged children in Soweto-Johannesburg are shown to be travelling substantial distances to school on a daily basis. Over a third travel more than 3 km one way to school, 60% attend schools outside of the suburb in which they live, and only 18% attend their nearest school. These data provide evidence for high levels of school choice in Johannesburg-Soweto, and that families and children are making substantial investments in pursuit of high-quality educational opportunities. Additionally, these data suggest that two patterns of school choice are evident: one pattern involving travel of substantial distances and requiring a higher level of financial investment and a second pattern involving choice between more local schools, requiring less travel and a more limited financial investment.     

GIS技术在萨拉乌苏考古遗址公园规划设计中的应用

传统规划设计工作的技术平台多以计算机辅助设计(CAD)为主,本工作以内蒙古自治区鄂尔多斯萨拉乌苏考古遗址公园规划为例,将Arc GIS Desktop作为技术平台应用到公园的规划设计工作中。首先,通过对规划区的实地踏勘,采集相关数据和资料,进行规划区数据库建设;其次,在数据库建设的基础上,通过GIS技术构建与现实环境对应的虚拟地理信息空间,实现规划区景观的三维可视化;最后,利用三维景观模型对现实地理环境进行模拟、分析及虚拟场景飞行。不同于传统CAD的二维工作平台,本工作借助GIS对空间数据和属性数据的强大处理功能及其三维景观可视化模块,为实现内蒙古鄂尔多斯萨拉乌苏考古遗址公园的科学规划提供辅助。     

“长江口二号”沉船出水青花瓷中的污染物研究

位于长江入海口的“长江口二号”清代沉船是中国目前发现的保存最为完整的古代木制沉船之一，已于2022年11月完成整体打捞。在进行水下考古调查时，沉船出水的部分青花瓷出现的病害现象引起了考古工作者的关注，特别是裂纹中黑色污染物及表面铁锈状污染物对文物的外观产生了很大影响。本工作选取了三件具有典型被污染特征的青花瓷标本作为代表，使用能量色散X射线荧光分析(EDXRF)、光学显微镜(OM)、X射线衍射分析(XRD)、拉曼光谱分析(Raman)和扫描电子显微镜-能谱分析(SEM-EDS)等方法，对污染物进行了研究，探讨了其形成原因以及环境的影响作用，并对其潜在危害进行了分析。研究表明，污染物主要以方解石、菱铁矿等碳酸盐以及铁的氧化物、氢氧化物和硫化物为主。长期处于河口淤泥中的还原性环境是导致菱铁矿和亚稳的铁硫化物形成的原因，船体中铁质构件腐蚀对局部环境的污染是重要的影响因素，这也反映出被污染的青花瓷所处位置和环境的特殊性。出水的部分青花瓷釉中裂纹的形态表明其形成是由物理撞击造成，而釉中硅灰石晶体的选择性腐蚀会导致腐蚀坑的形成，裂纹和腐蚀坑均为外部污染物进入釉层内部提供了通道，导致瓷器劣化。出水后...     

Twins in prehistory: The case from Olèrdola (Barcelona,Spain; s. IV II BC)

This paper details the discovery of two perinatal individuals interred simultaneously at the archaeological site of Olèrdola, Barcelona, Spain. Information from the excavation and from the subsequent anthropological study of the recovered skeletal and dental remains suggests that these individuals (OL–2000–8245 and OL–2000–8246) are the first documented case of twins in Iberian period. The possibility of a simultaneous perinatal twins burial at Olèrdola raises new questions concerning about the frequency of twins in prehistory and protohistory. Copyright © 2010 John Wiley & Sons, Ltd.     

Use of ground penetrating radar to map subsurface archaeological features in an urban area

The ground penetrating radar (GPR) technique was used to investigate the subsurface in an urban area located in Mesagne (Italy) to obtain a map of the archaeological features in the ground. The GPR survey was undertaken at selected locations placed near (about 50 m) to a necropolis dating from the Messapian to the Roman imperial age, using a GSSI Sir System 2 incorporating 200 and 500 MHz centre frequency antennae. The selected areas (A and B) were surveyed along parallel 1 m spaced profiles using a 200 MHz antenna in area A and along parallel 0.5 m spaced profiles using a 500 MHz antenna in area B. For the selected areas the processed data were visualised in 3D space not only by means of the standard time slice technique, but also by means of a recently proposed approach, namely by iso-amplitude surfaces of the complex trace amplitude. The immediacy in revealing the spatial positioning of highly reflecting bodies, such as the anomaly interpreted as an old hypogeum room in area A, makes 3D visualisation techniques very attractive in archaeological applications of GPR. Their sensitivity to the signal/noise ratio is, on the other hand, highlighted by the quite poor performance in area B, where the only reliable result provided by all the techniques was the ancient living surface reflection, whereas none of them could effectively enhance the visibility of weak hyperbola reflections noted on 2D sections and probably related to the walls located on the ancient living surface. The performance of the various techniques in these two different situations allowed insights into their main advantages and drawbacks to be gained.     

英国新社会史思潮的兴起及其整体社会史研究的国际反响

“新社会史研究”作为一种史学新思潮,与西方史学的整体化趋势,几乎同时出现于现代国际史学舞台。英国新社会史思潮具有广泛和深刻的国内外史学渊源。英国新社会史学派宣扬的核心问题是坚持“自下而上”史学观念,它彰显了由此观念指导下的整体社会史取向和研究实践。从较广泛的分析角度看,在国际史学发展格局重新调整的现时背景下,英国马克思主义新社会史学派引起国内外史学界的广泛注意和效仿。它对国际史学发展的推动性作用是不可忽视的,这集中体现了该学派及其整体史学研究的国际反响。     

20世纪50年代中国在引进基础上的技术创新

20世纪50年代中国的技术引进和技术创新活动集中在“一五”时期和“大跃进”时期,虽然这两个时期在引进基础上的创新活动都是在重工业优先发展战略下的体制框架内进行的,但在引进技术的行业构成、规模、项目建设的实施和技术的消化乃至技术创新机制、成效等方面都有所不同。“一五”时期采用了全面、系统、灵活多样的方式和重点攻关,在消化、吸收引进技术方面取得了明显的成效,某些领域实现了技术再造,技术创新能力得到了迅速积累,但从总体上看仍处于对引进技术的翻版、修改阶段。“大跃进”时期的技术创新机制被严重干扰,群众运动代替了深入细致的科学研究,在群众性技术革新运动中引进基础上的创新活动格外活跃,通过技术革新运动学会了自行制造一些成套设备、生产工艺,但并没有从产业部门或行业整体上真正实现引进基础上的再次创新,其整体水平依然停留在对引进技术的“初级模仿”阶段。     

Real‐time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U‐tube sampling methodology

Sampling of fluids in deep boreholes is challenging because of the necessity of minimizing external contamination and maintaining sample integrity during recovery. The U‐tube sampling methodology was developed to collect large volume, multiphase samples at in situ pressures. As a permanent or semi‐permanent installation, the U‐tube can be used for rapidly acquiring multiple samples or it may be installed for long‐term monitoring applications. The U‐tube was first deployed in Liberty County, TX to monitor crosswell CO₂ injection as part of the Frio CO₂ sequestration experiment. Analysis of gases (dissolved or separate phase) was performed in the field using a quadrupole mass spectrometer, which served as the basis for determining the arrival of the CO₂ plume. The presence of oxygen and argon in elevated concentrations, along with reduced methane concentration, indicates sample alteration caused by the introduction of surface fluids during borehole completion. Despite producing the well to eliminate non‐native fluids, measurements demonstrate that contamination persists until the immiscible CO₂ injection swept formation fluid into the observation wellbore.     

Chemical and isotopic signatures of Na/HCO3/CO2‐rich geofluids,North Portugal

Geochemical and isotopic studies have been undertaken to assess the origin of CO₂‐rich waters issuing in the northern part of Portugal. These solutions are hot (76°C) to cold (17°C) Na–HCO₃ mineral waters. The δ²H and δ¹⁸O signatures of the mineral waters reflect the influence of altitude on meteoric recharge. The lack of an ¹⁸O‐shift indicates there has been no high temperature water–rock interaction at depth, corroborating the results of several chemical geothermometers (reservoir temperature of about 120°C). The low ¹⁴C activity (up to 9.9 pmC) measured in some of the cold CO₂‐rich mineral waters (total dissolved inorganic carbon) is incompatible with the presence of ³H (from 1.7 to 4.1 TU) in those waters, which indicates relatively short subsurface circulation times. The δ¹³C values of CO₂ gas and dissolved inorganic carbon range between ?6‰ and ?1‰ versus Vienna‐Peedee Belemnite, indicating that the total carbon in the recharge waters is being diluted by larger quantities of CO₂ (¹⁴C‐free) introduced from deep‐seated (upper mantle) sources, masking the ¹⁴C‐dating values. The differences in the ⁸⁷Sr/⁸⁶Sr ratios of the studied thermal and mineral waters seem to be caused by water–rock interaction with different granitic rocks. Chlorine isotope signatures (?0.4‰ < δ³⁷Cl < +0.4‰ versus standard mean ocean chloride) indicate that Cl in these waters could be derived from mixing of a small amount of igneous Cl from leaching of granitic rocks.     

The Impact of Global Financial Crisis on the Mechanism of Economic Growth in Russia

A noted specialist on the Russian economy presents an assessment of the impact of the global financial crisis on the mechanism of the country's economic growth. Focusing on the demand side of the economic ledger, the author explores the question of whether Russia will be able to re-attain the high economic growth rates of the period from 2000 to 2007 after recovering from the crisis. The paper analyzes the sharp drop in production in 2008 and the first quarter of 2009, attributing most of the damage to liquidity problems and declines in the price of oil. Empirical evidence is based primarily on data collected by the author from the Central Bank of Russia and the country's federal bureau of statistics (Rosstat). Journal of Economic Literature, Classification Numbers: E010, E200, E660, F210, G010. 11 figures, 3 tables, 29 references.