The astysphere and urban geochemistry—a new approach to integrate urban systems into the geoscientific concept of spheres and a challenging concept of modern geochemistry supporting the sustainable development of planet earth

Background, aim, and scope  In 1875, the geoscientist Walter Suess introduced several spheres, such as the lithosphere and the atmosphere to promote a comprehensive understanding of the system earth. Since then, this idea became the dominating concept for the understanding of the distribution of chemical elements in the system earth. Meanwhile, due to the importance of human beings on global element fluxes, the term anthroposphere was introduced. Nevertheless, in face of the ongoing urbanization of the earth, this concept is not any more adequate enough to develop a comprehensive understanding of global element fluxes in and between solid, liquid, and gaseous phases. This article discusses a new concept integrating urbanization into the geoscientific concept of spheres. Main features  No geological exogenic force has altered the earth’s surface during the last centuries in such an extent as human activity. Humans have altered the morphology and element balances of the earth by establishing agrosystems first and urban systems later. Currently, urban systems happen to become the main regulators for fluxes of many elements on a global scale due to ongoing industrial and economic development and a growing number of inhabitants. Additionally, urban systems are constantly expanding and cover more and more former natural and agricultural areas. For nature, urban systems are new phenomena, which never existed in previous geological eras. The process of the globe’s urbanization concurrently is active with the global climate change. In fact, urban systems are a major emitter for climate active gases. Thus, beside the global changes in economy and society, urbanization is an important factor within the global change of nature as is already accepted for climate, ecosystems, and biodiversity. Results  Due to the fact that urbanization has become a global process shaping the earth and that the urban systems are globally cross-linked among each other, a new geoscientific sphere has to be introduced: the astysphere. This sphere comprises the parts of the earth influenced by urban systems. Accepting urbanization as global ongoing process forming the astysphere comprehensively copes with the growing importance of urbanization on the creation of present geologic formations. Discussion  Anthropogenic activities occur mainly in rural and urban environments. For long lasting periods of human history, human activities mainly were focused on hunting and agriculture, but since industrialization, urbanized areas became increasingly important for the material and energy fluxes of earth. Thus, it seems appropriate to classify the anthroposphere into an agriculturally and an urban-dominated sphere, which are the agrosphere (Krishna 2003) and the astysphere (introduced by Norra 2007). Conclusions  We have to realize that urban systems are deposits, consumers, and transformers of resources interacting among each other and forming a network around the globe. Since the future of human mankind depends on the sustainable use of available resources, only a global and holistic view of the cross-linked urban systems forming together the astysphere provide the necessary geoscientific background understanding for global urban material and energy fluxes. If we want to ensure worth-living conditions for future generations of mankind, we have to develop global models of the future needs for resources by the global metasystem of urban systems, called astysphere. Perspectives  The final vision for geoscientific research on the astysphere must be to design models describing the global process of urbanization of the earth and the development of the astysphere with respect to fluxes of materials, elements, and energy as well as with respect to the forming of the earth’s face. Besides that, just from the viewpoint of fundamental research, the geoscientific concept of spheres has to be complemented by the astysphere if this concept shall fully represent the system earth.

不同来源污泥接种餐厨垃圾厌氧发酵产氢效果研究

在相同接种配比(接种污泥占餐厨垃圾的质量分数为30%)条件下,研究了4种不同来源污泥(压滤污泥、厌氧污泥、曝气污泥和河底淤泥)添加或不添加缓冲剂时对餐厨垃圾厌氧发酵产氢效果的影响.结果发现,在不添加缓冲剂时.4种污泥接种餐厨垃圾厌氧发酵平均产氢量依次为厌氧污泥>河底淤泥>压滤污泥>曝气污泥,接种厌氧污泥的餐厨垃圾平均产氢量最高,达10.11mL(以每克挥发性固体(VS)计,下同);而添加缓冲剂时.4种污泥接种餐厨垃圾厌氧发酵平均产氢量依次为厌氧污泥>曝气污泥>压滤污泥>河底淤泥,接种厌氧污泥的餐厨垃圾平均产氢量也最高,为33.72 mL,且体系pH得以缓冲.     

Modelling the long-term consequences of a hypothetical dispersal of radioactivity in an urban area including remediation alternatives

The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes the second of two modelling exercises. This exercise was based on a hypothetical dispersal of radioactivity in an urban area from a radiological dispersal device, with reference surface contamination at selected sites used as the primary input information. Modelling endpoints for the exercise included radionuclide concentrations and external dose rates at specified locations, contributions to the dose rates from individual surfaces, and annual and cumulative external doses to specified reference individuals. Model predictions were performed for a “no action” situation (with no remedial measures) and for selected countermeasures. The exercise provided an opportunity for comparison of three modelling approaches, as well as a comparison of the predicted effectiveness of various countermeasures in terms of their short-term and long-term effects on predicted doses to humans.     

The social context of childcare practices and child malnutrition in Niger's recent food crisis

In 2004–05, Niger suffered a food crisis during which global attention focused on high levels of acute malnutrition among children. In response, decentralised emergency nutrition programmes were introduced into much of southern Niger. Child malnutrition, however, is a chronic problem and its links with food production and household food security are complex. This qualitative, anthropological study investigates pathways by which children are rendered vulnerable in the context of a nutritional 'emergency'. It focuses on household-level decisions that determine resource allocation and childcare practices in order to explain why practices apparently detrimental to children's health persist. Risk aversion, the need to maintain self-identity and status, and constrained decision making result in a failure to invest extra necessary resources ingrowth-faltering children. Understanding and responding to the social context of child malnutrition will help humanitarian workers to integrate their efforts more effectively with longer-term development programmes aimed at improving livelihood security.     

安徽省耕地资源数量变化及其对粮食安全的影响

利用1978年以来30年的耕地资源统计数据,分析了安徽省耕地资源数量变化总体特征,探讨了耕地资源数量变化对粮食安全的影响。其结果表明：（1）耕地资源总量和人均耕地占有量均有呈直线递减趋势,其中耕地资源总量年均减少率为024%,人均耕地面积年均减少率为115%。（2）粮食产量总体呈增加趋〖JP2〗势,但具有较明显波动性,粮食安全仍将面临着很大挑战。（3）粮食总产量与单产水平和复种指数密切相关;而粮食总产量年变化率,则主要受耕地面积和粮食播种面积变化影响。1978年以来,耕地资源数量逐渐成为影响该省粮食产量增加的主要限制因子.     

Requirements for estimation of doses from contaminants dispersed by a ‘dirty bomb’ explosion in an urban area

The ARGOS decision support system is currently being extended to enable estimation of the consequences of terror attacks involving chemical, biological, nuclear and radiological substances. This paper presents elements of the framework that will be applied in ARGOS to calculate the dose contributions from contaminants dispersed in the atmosphere after a ‘dirty bomb’ explosion. Conceptual methodologies are presented which describe the various dose components on the basis of knowledge of time-integrated contaminant air concentrations. Also the aerosolisation and atmospheric dispersion in a city of different types of conceivable contaminants from a ‘dirty bomb’ are discussed.     

Air ventilation impacts of the “wall effect” resulting from the alignment of high-rise buildings

The objective of this study is to investigate the air ventilation impacts of the so called “wall effect” caused by the alignment of high-rise buildings in complex building clusters. The research method employs the numerical algorithm of computational fluid dynamics (CFD – FLUENT) to simulate the steady-state wind field in a typical Hong Kong urban setting and investigate pollutant dispersion inside the street canyon utilizing a pollutant transport model. The model settings of validation study were accomplished by comparing the simulation wind field around a single building block to wind tunnel data. The results revealed that our model simulation is fairly close to the wind tunnel measurements. In this paper, a typical dense building distribution in Hong Kong with 2 incident wind directions (0° and 22.5°) is studied. Two performance indicators are used to quantify the air ventilation impacts, namely the velocity ratio (VR) and the retention time (T_r) of pollutants at the street level. The results indicated that the velocity ratio at 2 m above ground was reduced 40% and retention time of pollutants increased 80% inside the street canyon when high-rise buildings with 4 times height of the street canyon were aligned as a “wall” upstream. While this reduction of air ventilation was anticipated, the magnitude is significant and this result clearly has important implications for building and urban planning.     

In-stand scenic beauty of variable retention harvests and mature forests in the U.S. Pacific Northwest: The effects of basal area, density, retention pattern and down wood

Tensions between amenity- and timber-based economies in the U.S. and Canadian Pacific Northwest motivated a study of scenic beauty inside mature forests and timber harvests. A diverse sample of regional forests, measures of forest structure, and large, representative samples of photographs and public judges were employed to measure scenic beauty inside un-harvested mature and old-growth forests, and timber harvests. The latter varied systematically in down wood levels and retention level and pattern. Scenic beauty tended to be optimized at a basal area of 110–155 m³/ha and/or 700–900 trees/ha. Older forests and those with larger trees were perceived to be more beautiful. In harvests, greater retention levels, less down wood, and dispersed rather than aggregated retention patterns contributed to aesthetic improvements. Green-tree retention harvests offer considerable potential gains in perceived scenic beauty compared to perceived very ugly clearcuts, particularly at higher retention levels. These gains are more reliable from dispersed retention patterns. The silvicultural parameters studied change strength in affecting scenic beauty with changes in retention level. These interactions are explored in relation to a range of scenic quality objectives as an aid to planners, visual impact analysts, and silviculturists.     

Participatory diagnosis in urban planning: proposal for a learning process based on geographical information

Urban planning involves compromise between the diverse and often contradictory issues supported by the different stakeholders. The literature generally agrees on the need to broaden the participation base to overcome this difficulty. However, participation should not be limited to problem solving, but should also take place in the problem setting phase. This paper proposes a participatory diagnosis process for structuring the problem setting phase. We describe an experiment in a participatory diagnosis conducted with the residents of a Geneva neighborhood. The experiment began by identifying the residents' concerns, which were then reformulated under broader issues. Some 20 spatial indicators were built using GIS tools, and were then applied in a second phase of resident consultations to assess the relative importance of each issue. The ensuing priority issues formed the core of the diagnosis. The approach emphasized comparison between the daily experiences of residents and so-called official information (i.e. census tract, traffic measurement, and so on). The residents were therefore involved in a learning process that allowed them to consolidate or modify their opinions. The process led to the emergence of a clearly defined collective awareness that supplanted individual aspirations.     

Rapid Assessment of Urban Wetlands: Do Hydrogeomorphic Classification and Reference Criteria Work?

The Hydrogeomorphic (HGM) functional assessment method is predicated on the ability of hydrogeomorphic wetland classification and visual assessment of alteration to provide reference standards against which functions in individual wetlands can be evaluated. The effectiveness of this approach was tested by measuring nitrogen cycling functions in forested wetlands in an urbanized region in New Jersey, USA. Fourteen sites represented three HGM classes and were characterized as “least disturbed reference” or “non-reference” based on initial visual assessment. Water table levels and in situ rates of net nitrogen mineralization, net nitrification, and denitrification were measured over one year in each site. Hydrological alterations, resulting in consistently low or flashy water table levels, were not correlated with a priori designations as reference and non-reference. Although the flat-riverine wetland class had lower net nitrification and higher denitrification rates than riverine or mineral flat wetland classes, this difference was attributable to the lack of hydrologically-altered wetlands in the flat-riverine class, and thus more consistently wet conditions. Within all HGM classes, a classification based on the long-term hydrological record that separated sites with “normal,” saturated hydrology from those with “altered,” drier hydrology, clearly distinguished sites with different nitrogen cycling function. Based on these findings, current practices for designating reference standard sites to judge wetland functions, at least in urbanized regions, are ineffective and potentially misleading. At least one year of hydrological monitoring data is suggested to classify wetlands into groups that have different nutrient cycling functions, particularly in urban landscapes.