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1.
The conurbation of Khartoum has been long the main destination area of the rural-urban migration in the Sudan. The town-planning office has become unable to provide the inmigrant masses with the least required housing infrastructure. The result is that the inmigrants have been living for some decades now in squatter areas without any right of residence. The way from the formation of a squatter settlement which is officially non-existent and illegal to a demarcated residential area is long and tedious. The author describes this process using the example of Um Badda which is a traditional destination area of inmigrants. The analysis shows that the officials of the town-planning treat the ethnic groups on unequal basis with a strong bias against southern Sudanese.  相似文献   

2.
Awan Yath Yath 《GeoJournal》1995,36(1):93-101
The magnitude of housing demand and the inadequacy of public housing in most cities of the Third World have led to the emergence of types of housing which, while having different names, are classified as squatter settlements. In Khartoum, the expansion of squatter settlements has mainly been due to political processes that resulted in dramatic urban needs generated by uneven development, widespread migration, demographic growth and income inequalities. In the recent years, however, rural recession, civil war, drought, floods and famine combined to turn the Sudanese capital city into a reception centre for a considerable number of displaced people from areas affected. Here the bulk of the displaced persons found accommodation in huts that they built themselves. The government responded to such a situation by embarking on a large scale deportation programme. Attempts to bargain, resist, or to cope with the political system, on the part of the displaced people, proved to be in vain. Available estimates suggest that at least two thirds of the two or more million migrants who moved to Khartoum during the last sixteen years, have now been forcibly driven back to rural areas.  相似文献   

3.
Today, more than one third of the population of Khartoum are southerners who migrated to the capital mainly in the last eight years because of the civil war. Their conditions are very bad. They are starving in the town, for most of them are unemployed and have no means of living. Their housing conditions in the shanty towns are deplorable. The development of squatter settlements and the struggle for the demarcation of quarters are delineated in this paper. In Khartoum the southerners develop a strong sense of solidarity and develop a growing supra-southern-Sudanese identity replacing the former ethnic and local identities.  相似文献   

4.
The aquifer system of the Basin of Mexico is the main source of water supply to the Mexico City Metropolitan Zone. Management of the Basin’s water resources requires improved understanding of regional groundwater flow patterns, for which large amounts of data are required. The current study analyses the regional dynamics of the potentiometric groundwater level using a new database called the Basin of Mexico Hydrogeological Database (BMHDB). To foster the development of a regional view of the aquifer system, data on climatological, borehole and runoff variables are part of the BMHDB. The structure and development of the BMHDB are briefly explained and then the database is used to analyze the consequences of groundwater extraction on the aquifer’s confinement conditions using lithology data. The regional analysis shows that the largest drawdown rates are located north of Mexico City, in Ecatepec (a region that has not yet received attention in hydrogeological studies), due to wells that were drilled as a temporary solution to Mexico City’s water-supply problem. It is evident that the aquifer has changed from a confined to an unconfined condition in some areas, a factor that is responsible for the large subsidence rates (40 cm/year) in some regions.  相似文献   

5.
The 19 September 1985 (Mw8.1) earthquake, located on the Michoacán coast, Mexico, generated great damage in Mexico City, more than 300 km away from the epicentral area. Other important cities near the coast and in central Mexico also suffered severe damage. Thirty years after this important event, the National Autonomous University of Mexico (UNAM), the Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE) and other institutions organized a conference to discuss the scientific advances, particularly in seismology, that had taken place in Mexico since then.  相似文献   

6.
The Basin of Mexico is a closed basin of lacustrine character, with an average elevation of 2200 m above sea level. The watershed covers a vast extension in five states. Mexico City and its metropolitan area are located within this basin. The aquifer system is the main source of water supply for more than 20 million people. Water consumption is about 60 m3/s. The aquifer supplies about 43 m3/s from around 1000 wells at 70–200 m depth. Pumping policies have generated subsidence and degradation of the ground water quality in the Basin of Mexico The lacustrian clay layers play an important role in the local hydrogeology, protecting the aquifer from pollution, but the transition and piedmont areas are highly vulnerable to surface pollutants.  相似文献   

7.
Summary The severity of damage to Mexico City as a result of the 19 September 1985 Michoacan earthquake was unusual given the city's distance (350 km) from the zone of seismic energy release. To explain the damage many authors have suggested that unusual source or transmission path characteristics contributed to enhanced ground motion in Mexico City. The purpose of this paper is to present a summary of results obtained from data recorded during the earthquake related to possible anomalous source characteristics.It is concluded that although the Michoacan earthquake was a large earthquake indeed, in terms of energy output, spectral content, geometry and source mechanics it was not remarkable or anomalous relative to other subduction zone earthquakes in Mexico or elsewhere. In fact the future may well see a larger earthquake generated along the Guerrero seismic gap which is significantly closer to Mexico City.  相似文献   

8.
Natural Hazards - We present a Risk Atlas of Mexico City based on a Geographical Information System (RA-GIS). We identified the prevalent social risk to the more relevant hazards in Mexico City...  相似文献   

9.
《Atmósfera》2014,27(3):261-271
Air pollution is the main environmental issue in Mexico City, where ozone is one of the most damaging pollutants for human health. In this work we present a retrospective health impact assessment (HIA) study split up by age groups for evaluating the benefits of ozone regulatory strategies from 1991 to 2011 in Mexico City. Since people move from one place to another during the day, which may affect their potential exposure to pollutants, we consider time-dependant spatial population distributions during the day. Ozone data is made up of observations taken with hourly frequency from January 1, 1991 to December 31, 2011, at approximately 22 stations of the monitoring network of Mexico City. Interpolated values for unknown locations are also taken into account in the HIA. The Cressman objective analysis method is applied for interpolating the observed ozone concentrations from monitoring stations to grids of convenient resolution. We demonstrate that different age groups present different spatial patterns of exposure, being the working-age people (between 18 and 64 years) the most benefited. We also confirm the hypothesis that, in general, people move to less polluted regions during the day.  相似文献   

10.
Summary The severity of damage to Mexico City as a result of the 19 September 1985 Michoacan earthquake was unusual given the City's distance (350 km) from the zone of seismic energy release. To explain the damage many authors have suggested that unusual source or transmission path characteristics contributed to enhanced ground motion in Mexico City. The purpose of this paper is to present a summary of results obtained from data recorded during the earthquake related to possible anomalous transmission path characteristics.It is concluded that in every respect this earthquake conformed to the norms set by previous subduction zone earthquakes within the Middle American trench. It appears likely that conditions within the Valley of Mexico are adequate to explain the unusually severe ground shaking without invoking unusual source or transmission characteristics.  相似文献   

11.
We developed a model to estimate seismic vulnerability of health facilities in Mexico City, Mexico, following these steps: (1) designing a theoretical framework (TF) to measure structural, non-structural, functional, and administrative-organizational vulnerabilities; (2) measurement of the vulnerability conditions of the analyzed facility by using the TF; and (3) estimation of the hospital’s seismic vulnerability by comparing the measured vulnerability to the TF’s vulnerability indicators by taking into account the optimal case. The TF was developed considering a scoring system and international standards for risk management in hospitals. The methodology establishes the degree of vulnerability of the analyzed institution as well as its interrelations with external infrastructure systems. This tool also identifies existing failures to estimate expected damage. The methodology was applied to the National Cardiology Hospital, the Children’s Hospital “Dr. Federico Gómez,” and the “Hospital de Jesus” of Mexico City. The vulnerability problems in these three hospitals are common within them, and some of the main causes of vulnerability found are: (1) the lack of technology to resistant seismic shaking; (2) the need to develop or update disaster response plans; (3) the need of periodic and proper maintenance to hospitals’ buildings; (4) the lack of sufficient financial resources for vulnerability reduction projects and autonomous operations of the hospital during 3–5 days after a disaster occurs. We believe that vulnerability in these health facilities can be reduced with low-cost procedures and that the methodology developed here will support the decision-making processes to reduce seismic risk in Mexico City.  相似文献   

12.
Heidi Hausermann 《Geoforum》2012,43(5):1002-1013
This article argues that everyday practices can matter as much as organized social movements or outright resistance in environmental governance outcomes. While governance has become an important analytical category for understanding the institutional and epistemological systems through which resources are accessed and managed, existing characterizations of environmental governance are based on organized social movements and/or institutional re-scalings. This research reveals how state strategies to govern resources and reorder space were thwarted by the everyday practices of both farmers and state actors. Using a case study from a historic coffee-producing region in Veracruz, Mexico, this article presents ethnographic data to demonstrate how government attempts to control the environment are bound together in mutually constitutive processes of transformation with the actual places, peoples, and practices that make up the landscape.  相似文献   

13.
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14.
The nature-society system is proposed as the relevant analytical unit for the sociological study of disasters. Like other complex systems, this system has emergent properties: its instabilities are the disasters. They often arise as a result of adoption by a community of specific technologies, e.g., housing technologies, that turn out to be unstable in the presence of critical natural or social changes. The following earthquake disasters were caused by unplanned and unforeseen features of housing or siting technologies: Huaxian 1556 (caves in loess), Yungay 1970 (siting in the path of an avalanche), and Mexico 1985 (high-rise buildings on soft ground). Disasters have anarchaeology, in the sense that the instabilities in the nature-society system are not static. This is demonstrated by tracing the 1985 Mexico earthquake disaster back to decisions on urban planning taken after 1521. It is not enough to know the hazard and the vulnerability in order to understand disasters. Technological solutions also have a local history.  相似文献   

15.
Concentrations of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were measured in 13 surficial sediment samples collected at three lacustrine locations in the surroundings of Mexico City and four coastal areas of the States of Sinaloa, Sonora, Oaxaca and Veracruz. Total PCB concentrations span the interval 3.18–621 ng g−1. The highest values (63.7–621 ng g−1) were found in Mexico City, which is a highly anthropogenically impacted area, whereas low concentrations (3.18–12.9 ng g−1) were characteristic of seven places, some of them subject to intense hydrodynamics. In these latter cases, values increase by 18–73 times if normalised against the fine fraction (silt plus clay) content in sediment. Two samples from Mexico City exceed the ERM (Effect Range Median) guidelines and are likely to cause adverse effects. Samples contain only lower chlorinated PCBs (mainly 2-, 3- and 4-CB), thus suggesting that the most used PCB commercial mixture was Aroclor 1242. The homologue composition of the sample taken close to the nuclear power plant of Laguna Verde is identical to this commercial mixture. PAHs in the same samples have relatively low concentrations (14.9–287 ng g−1), well below ERL (Effect Range Low) guidelines. The composition of PAH mixtures accounts for the influence of both petrogenic and pyrolitic sources, with these latter prevailing at some places in Mexico City.  相似文献   

16.
Conclusion The sporadic application of ‘slum clearance’ programmes served only to exacerbate the already intransigent problem of urban housing shortage, as the example of Lagos has demonstrated. The continued application of Western assumptions in urban development (whereas they have since been modified in those countries) has inhibited a reassessment of issues in the Nigerian context. Some of the issues at stake have been considered in this paper. Conventional Western concepts have not only proved inappropriate to the realities of rapid urban growth and limited resources in Nigeria and most of tropical Africa, but have intensified the problems still further. In the context of Maroko slum clearance exercise as contained in this paper, they must be seen as an unsuccessful attempt to control rather than resolve the housing problems of the urban poor. I terms of planning five procedural steps are necessary to be followed to accomplish a desirable urban renewal exercise for the community. They are (1) to acquire land in accordance with the plan, consisting of purchase of land and the structures on it. (2) Relocation of residents from the acquired buildings into satisfactory quarters. The relocation exercise must be made not only mandatory on the government (local or state) undertaking renewal but made a legal requirement. (3) Site clearance — the razing of the structures on the land may be carried out only after the quality of such structures have been determined. This exercise also assumes that a process of data collection and analysis have been accomplished (social and physical). (4) Site improvements and supporting facilities and services are undertaken by the agency. Site improvements include streets, sewers, lightiing etc. Others may include parks, play ground, schools etc. (5) Land may be built upon by agency or sold to original owners if compensations have been paid. They may also be given back to owners with loans to rebuild either through self-help or cooperative venture. Amortization and interest on such loans should be made generous for the poor. Since demolition of housing must precede new construction in the project area, the existing stock of housing is decreased, forcing the displacees to seek shelter in the remaining housing in the city or erect squatter housing. This is especially likely at the low-quality end of the housing market, since the greatest reduction in the housing stock occurs there. The condition may remain depending on government’s degree of responsiveness. Perhaps the only way to avoid the problem of a reduced housing stock in any urban renewal project, thus curbing the incidence of the spiral process of slums among the poor, as the Maroko example has demonstrated in Lagos, is by building new dwelling units for relocatees before demolishing their present homes. Such policy would merge with general attempts to relocate the poor in suburbs, seeking a reduction in the concentrations of poverty in central cities of Nigeria.  相似文献   

17.
陈华 《福建地质》2011,30(4):278-285
宁德九曲岭含铜钨矿隐爆角砾岩筒出露于花岗闪长岩体之中,未见明显断裂控制。隐爆角砾成分与胶结物成分复杂,矿化蚀变具明显的分带特征,其中铜钨矿贮存于黄铁矿一绿泥石和石英一绿泥石带中。外围尚发现2个大型隐爆角砾岩筒,通过研究九曲岭铜钨矿角砾岩筒特征,对指导深部与外围找矿具有重要找矿意义。  相似文献   

18.
The first evaluation of the distribution of platinum group elements (PGE) derived from automobile catalytic converters in urban soil samples in Mexico City was carried out. There are more than four millions cars in Mexico City and, at the present time, one third of them have catalytic converters. PGE concentrations in soils exposed to high traffic densities exceed the natural background values by upto two orders of magnitude and are directly influenced by traffic conditions. The highest concentrations of Pt, Pd and Rh in the analyzed samples are about 300, 70 and 40 μg/l, respectively. Although the PGE concentrations found in soil samples are relatively low, they represent an accumulation of only 10 yr. It is likely that the use of catalytic converters will dramatically change the distribution of these metals in the urban environment in the next decades.  相似文献   

19.
This study reports the degree of heavy metal pollution (Cr, Cu, Ni, Pb, Zn and V) in 135 urban topsoil samples from the metropolitan area of Mexico City. Pollution indices (PI) were calculated to identify the metal accumulation with respect to the background values. The levels of heavy metals in the analyzed samples show a wide range of variation. Lead, Zn and Cu are the elements most enriched in the analyzed area, presenting pollution indexes of up to 23.8, 21.6 and 12.4, respectively. Geochemical maps were produced to assess the spatial distribution of pollution index. It is concluded that emissions from vehicles may be the major source of Pb urban contamination; furthermore, other small or large factories are possible sources for soil pollution (Cu, Zn). The concentration of Cr, Ni, and V in most of the analyzed samples do not appear to reach pollution levels. The assessment of the soil environmental quality in the metropolitan area Mexico City in terms of PI can be used as the basis for a regular monitoring program for implementing suitable pollution control measures.  相似文献   

20.
The crisis and challenges faced by labor, including the trade unions and social movements have proportions not yet fully understood. The repercussions, owing to globalization, also reached Third World countries, especially intermediate countries that hold important industrial estates such as Brazil, Mexico, Argentina, etc. Brazil is part of an economic, social, political and cultural context which has universal traces of global capitalism, but also possesses singularities. During the last decades, Brazilian trade unions and social movements have either followed a different path. There was a widespread and highly significant strike movement (in the 1980s) with a notable expansion of trade unions organizing salaried sector (teachers, bank workers, public sector workers, etc.); there was also the rise of the Union Congresses such as the CUT-Central Única dos Trabalhadores (Workers Central) and the advance of rural unionism and the Landless Workers' Movement (MST, Movimento dos Trabalhadores Sem Terra) and new urban social movements such as the Homeless Movement. By the end of these decades, we joined in a more significant way the challenges which were presented to the unionism and social movements. These challenges are discuss in this paper.  相似文献   

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