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1.
Two fundamental issues surrounding research on Zipf’s law regarding city sizes are whether and why this law holds. This paper does not deal with the latter issue with respect to why, and instead investigates whether Zipf’s law holds in a global setting, thus involving all cities around the world. Unlike previous studies, which have mainly relied on conventional census data such as populations and census-bureau-imposed definitions of cities, we adopt naturally (in terms of data speak for itself) delineated cities, or natural cities, to be more precise, in order to examine Zipf’s law. We find that Zipf’s law holds remarkably well for all natural cities at the global level, and it remains almost valid at the continental level except for Africa at certain time instants. We further examine the law at the country level, and note that Zipf’s law is violated from country to country or from time to time. This violation is mainly due to our limitations; we are limited to individual countries, or to a static view on city-size distributions. The central argument of this paper is that Zipf’s law is universal, and we therefore must use the correct scope in order to observe it. We further find Zipf’s law applied to city numbers; the number of cities in the largest country is twice as many as that in the second largest country, three times as many as that in the third largest country, and so on. These findings have profound implications for big data and the science of cities.  相似文献   

2.
徐梦婕  刘陕 《地理教学》2014,(12):181-182
Nowadays,with the growing economic globalization,more and more people begin to learn English.Reading masterpieces and the translations of them at the same time is one of the best ways to improve one’s English.Thus people pay more attention to the translations of the masterpieces,and more and more scholars initiate to discuss the subject of translator’s subjectivity.My paper here will try to take Sun Zhili’s version of Jane Austen’s Pride and  相似文献   

3.
Africa’s recent growth successes are raising hopes that its cities can generate the positive externalities needed to sustain long-term development. This paper examines the prospects for such a transformation in Dar es Salaam, Tanzania. A sociotechnical systems framework is elaborated: one which conceptualizes urbanization pathways as determined by the practices, modes of governance, couplings, and multiscalar relations that constitute production, consumption, and infrastructure regimes in cities. The framework is deployed to assess whether Dar es Salaam’s industries, markets, public services, and built environments are generating distributive development outcomes. The analysis shows that the city is experiencing socioeconomically and spatially uneven development driven by processes of extraversion, intraversion, and splintering. Urban regimes are thus serving a more “parasitic” role by channeling capital offshore, bringing imports onshore, and creating highly uneven distributions of basic services. The paper highlights points of intervention and the value of the conceptual approach for comparative urban research.  相似文献   

4.
A growing number of commentators are forecasting a near-term peak and subsequent terminal decline in the global production of conventional oil as a result of the physical depletion of the resource. These forecasts frequently rely on the estimates of the ultimately recoverable resources (URR) of different regions, obtained through the use of curve-fitting to historical trends in discovery or production. Curve-fitting was originally pioneered by M. King Hubbert in the context of an earlier debate about the future of the US oil production. However, despite their widespread use, curve-fitting techniques remain the subject of considerable controversy. This article classifies and explains these techniques and identifies both their relative suitability in different circumstances and the level of confidence that may be placed in their results. This article discusses the interpretation and importance of the URR estimates, indicates the relationship between curve fitting and other methods of estimating the URR and classifies the techniques into three groups. It then investigates each group in turn, indicating their historical origins, contemporary application and major strengths and weaknesses. The article then uses illustrative data from a number of oil-producing regions to assess whether these techniques produce consistent results as well as highlight some of the statistical issues raised and suggesting how they may be addressed. The article concludes that the applicability of curve-fitting techniques is more limited than adherents claim and that the confidence bounds on the results are wider than usually assumed.  相似文献   

5.
Understanding the manifestations and underlying drivers of agricultural land use change in China is of great importance for both domestic and global food security.However,little is known about the holistic pattern of agricultural land use change across China,espe-cially from the perspective of intensity since the evidence has been gathered mainly through case studies at local levels.This study conducts a systemic review of agricultural land use change and its underlying drivers in China by aggregating 169 relevant case studies from 123 publications.The cases related to intensification and disintensification,which are the two types of agricultural land use change,are generally equal,accounting for 50% of the total number of cases.Intensification and disintensification can be further divided into the same three categories:expansion/contraction of agricultural land,changes in agricultural land use activities and changes in land management intensity.Demographic,economic,technological,and institutional drivers,together with location factors,are frequently noted as significant underlying drivers,while sociocultural drivers and farm(er) characteristics are less frequently recognized.Finally,three major land use change trajectories are summarized mainly con-ceming rising labor costs and the concomitant increase in off-farm employment,the ecologi-cal improvement policy,and advances in agricultural technology.  相似文献   

6.
In 2007, the Government of Ecuador announced the Yasuní-ITT Initiative: a proposal to forego exploiting 20% of its oil reserves located in the Yasuní National Park – home to one of the earth’s most biodiverse places and several indigenous groups living in voluntary isolation. In exchange, Ecuador asked the international community for $3.6 billion, roughly half the projected revenues of conventional oil extraction. Five years later, Ecuador received less than 10% of the required pledges and the initiative was canceled. Many accounts emphasized the then President Rafael Correa’s perceived untrustworthiness as key in explaining the initiative’s failure. This article instead examines the role of entrenched institutions of the petrostate, emphasizing how the initiative defied expectations by offering a post-extractivist path for Ecuador. Despite its failure, this horizon continues to orient debates on development and extractivism, forming “afterlives” of a call to mitigate climate change by leaving oil in the ground.  相似文献   

7.
In this study, we developed a theoretical framework to analyze the provincial differences in eco-compensation and selected appropriate measurement methods to investigate these differences in the operation of the eco-compensation framework. Via the use of the coefficient of variation, Atkinson index, and Gini coefficient, we investigated the overall differences in Chinese provincial eco-compensation time series data from 2004 to 2014 and studied the driving mechanism underlying these differences. The results showed that: (1) The provincial eco-compensation standard has geographical features. For example, the provinces crossed by the “HU Huanyong Line”, or located to its northwestern side, have obtained extensive eco-compensation. (2) There was a trend for differences in eco-compensation to increase over time, but with some fluctuations in 2006, 2009, and 2014 as shown by the coefficient of variation, in 2005, 2007, 2011, 2013, and 2014 as shown by the Gini coefficient, and in 2007, 2008, 2011, and 2012 as shown by the Atkinson index. (3) Time series curves indicated that while the signals from the three metrics (coefficient of variation, Atkinson index, and Gini coefficient) differ in a short-term analysis, they show the same tendency in the longer term. The results indicate that it is necessary to evaluate the differences in eco-compensation at the provincial level over a long period of time. (4) Via the calculation of the virtual Gini coefficient, we found that among the factors that influence provincial differences in eco-compensation, the economic value of eco-resources played the decisive role, explaining more than 73% of the difference. The cost of environmental pollution abatement was the second most important factor, accounting for more than 19% of the difference. The input to environmental pollution abatement had the least influence, accounting for less than 8% of the difference. The results agreed with those obtained from other studies, and could be used as a reference by policy makers.  相似文献   

8.
9.
This article explores the complex relationship between communal conflicts and antistate armed militancy in Nigeria’s Niger Delta. Based on fieldwork in rural communities, the research found that individuals who emerged as dominant actors as a result of their involvement in communal conflict were at the forefront of antistate militancy. The article highlights the role of antistate militancy in the Niger Delta in the emergence of new elites in local communities. It argues that antistate militants who became new elites in local communities are now being integrated into the network of Nigeria’s ruling class. Meanwhile, ordinary civilians that were not involved in antistate militancy continue to contest the dominance of these new elites in local communities. This situation tends to perpetuate community conflicts in Nigeria’s Niger Delta region.  相似文献   

10.
Abstract

This study examines the role of surface geomorphic features in tree establishment at the alpine treeline in Glacier National Park, Montana, through the presentation of a multiscale, conceptual model of biogeomorphic relationships at alpine treeline. Empirical observations gathered through a multiscale field methodology over three summers serve as a base for the model. The model highlights the importance of surface geomorphic features, specifically boulders and terrace risers, in creating favorable local site conditions, largely by protecting seedlings from wind. The sheltering effect of surface features enables initial seedling establishment, and in some cases survival, above current treeline locations, thereby initiating a positive feedback effect that encourages subsequent tree establishment. Geomorphic features are therefore important in linking scales of pattern and process at the alpine treeline ecotone.  相似文献   

11.
The City of Toronto has undergone a number of dramatic transformations in the last several decades morphing from an industrial-driven metropolis into a thriving real estate and consumer amenities market. Over these decades, the development of condominiums has significantly transformed Toronto’s cityscape surpassing by far other types of real estate development. Based chiefly on a series of interviews with property developers and local politicians, this article explores development from the perspective of condo developers. The article identifies the key condo developers and categorizes them according to their development approaches and spatial preferences. Findings reiterate the need to consider property developers as highly diverse and flexible place entrepreneurs. Differences play out not merely in preferred development location and size, but also in target population, tenure mix, corporate structure, and the extent to which capitalism and economic gain are mixed with more idealistic motivations such as social benefits.  相似文献   

12.
This article first provides a conceptual and theoretical analysis of international financial centers (IFCs) by focusing on IFCs’ main characteristics, categories, and policy regimes. It then reviews the policy initiatives driving Shanghai’s IFC, coming from the central and local governments, and evaluates their strategic effects. Finally, I emphasize the disadvantages of Shanghai’s IFC dynamics by focusing on the level of internationalization, the financial hinterland, the English professionals, and the legal system. The empirical study reveals that the construction of Shanghai’s IFC has achieved great advances, motivated by its policy dynamics since 1990, but its global impact is still limited compared to New York and London. This study sheds light on the dynamics of Shanghai’s IFC as a government-led model.  相似文献   

13.
Like many countries in sub-Saharan Africa, Ghana lacks well-engineered sanitary landfill sites. Increased urbanization and concomitant real estate growth lead landfills to compete with residential land use, resulting in closer proximity between landfill sites and residential neighborhoods. The effects of landfills on the property values of nearby residential communities have been the subject of much debate in the developed world, where state-of-the-art and environmentally well-engineered landfills are common. However, academic and other research is inconclusive on the effects of landfills on property values in the developed countries. This paper addresses this knowledge gap by exploring the effects of landfills on residential property values in Ghana, using the Oblogo and Mallam landfills in Accra as a case study. Our analysis indicates that while landfills do depress nearby residential property values, the effects are contingent on property location relative to the level of urbanization in a community, and year of completion and total costs of property development.  相似文献   

14.
In 1977, Taylor proposed a constant elasticity model relating capacity choice in mines to reserves. A test of this model using a very large (n = 1,195) dataset confirms its validity but obtains significantly different estimated values for the model coefficients. Capacity is somewhat inelastic with respect to reserves, with an elasticity of 0.65 estimated for open-pit plus block-cave underground mines and 0.56 for all other underground mines. These new estimates should be useful for capacity determinations as scoping studies and as a starting point for feasibility studies. The results are robust over a wide range of deposit types, deposit sizes, and time, consistent with physical constraints on mine capacity that are largely independent of technology.  相似文献   

15.
In this article, I analyze Tel Aviv’s Rothschild Boulevard as an example of an urban symbol and suggest that while main streets, avenues and boulevards are usually perceived as integral parts of the urban symbolic ecology, they are rarely considered as exclusive urban icons in their own right. Although prestige of “privileged” streets influences reputations of cities and constitutes an important part of their imaginary, their complicated physical structure and multifunctional character conflict with their iconic status. The physical nature of streets resists configuration and articulation as exclusive, durable urban icons because symbols are generally conspicuous physical objects that can be directly interpreted and rendered as iconic.  相似文献   

16.
China’s rapid urbanization has created large scale of population migration, resulting in many villages being dominated by “left-behind” women, and weak governance of those collectively owned resources. The situation has required these women to take up the functions of decision-making and governance as a remedial mechanism as well as a new path. Based on a case study in a typical hollowing-out village in central China, this paper explores an example of left-behind women’s collective action to prevent the over-exploitation of community and resources. It finds out that although traditionally excluded from public activities and marginalized, the “left-behind” women were able to mobilize and enhance collective action. When empowered, they are growing fast with endurance and courage, and as capable as anyone of defending the common-pool resources. It suggests that the left-behind women offer a new governance option for those population hollowing out rural areas.  相似文献   

17.
As the world’s largest developing country, the ability of China’s agricultural resource utilization to effectively support the current and future food security goals has been affected by a variety of factors (e.g., transformed supply channels, tightening international situation and frequent emergencies) in recent years and has attracted extensive attention from the academic community subject to multiple factors. This study uses literature review, statistical analysis, and spatial analysis methods to systematically explore China’s food security situation in the context of farmland resource constraints. It is found that the demand-side pressures such as demographic changes, social class differentiation, and dietary structure adjustments derived from economic growth and rapid urbanization have placed extremely high expectations on food supply. However, the quantitative restrictions, utilization ways, and health risks of farmland resources on the supply side constitute a huge hidden concern that affects the stability of food production. Although China’s farmland protection system is undergoing a transition from focusing on quantity management to sustainable use, the matching and coordinating demand pressure and supply capacity for food security is unbalanced. Therefore, facing uncertain future development scenarios, policymakers should focus on building a resilient space for China’s farmland protection to withstand the interference of major emergencies. The existing farmland protection space policy can be integrated by establishing a national farmland strategic reserve system (based on resilient space), and further development of targeted use control measures for zoning, grading, and classification will help realize sustainable China’s farmland resources use.  相似文献   

18.
A theoretical model of conventional oil production has been developed. The model does not assume Hubbert’s bell curve, an asymmetric bell curve, or a reserve-to-production ratio method is correct, and does not use oil production data as an input. The theoretical model is in close agreement with actual production data until the 1979 oil crisis, with an R 2 value of greater than 0.98. Whilst the theoretical model indicates that an ideal production curve is slightly asymmetric, which differs from Hubbert’s curve, the ideal model compares well with the Hubbert model, with R 2 values in excess of 0.95. Amending the theoretical model to take into account the 1979 oil crisis, and assuming the ultimately recoverable resources are in the range of 2–3 trillion barrels, the amended model predicts conventional oil production to peak between 2010 and 2025. The amended model, for the case when the ultimately recoverable resources is 2.2 trillion barrels, indicates that oil production peaks in 2013.  相似文献   

19.
We here respond to the critique by Purdon of an article on carbon forestry that we published in this journal last year (Carton and Andersson). While we welcome critical engagements with our work, Purdon’s argument is wide of the mark and appears based largely on misconceptions regarding our theoretical entry point and empirical findings. Underlying this are fundamental disagreements about the nature of carbon forestry, structure-agency dynamics, and how to understand environmental interventions in the global South more broadly. We argue that we are unlikely to “find common ground” in our respective analyses of the Trees for Global Benefits project unless we share a common understanding of the unequal power relations and fundamental geographical unevenness within which carbon projects operate. Contrary to what Purdon argues, this position has nothing to do with ignoring local benefits, nor with denying the agency of the smallholder farmers who participate in the project. We see no contradiction between an analysis that does justice to the various structural conditions that frame carbon forest projects, and a recognition of local agency.  相似文献   

20.
This paper sets out to evaluate the freedom of voice for Peruvian stakeholders affected by hydrocarbon development. This occurs through the utilization of a political ecology of voice (PEV) theoretical framework based upon the theory of voice by Albert Hirschman and political ecology. PEV can be defined as the study of economic, political, social, and geographical factors over a specific time period and their impact upon the use of voice by stakeholders. Peru’s case study was focused on its main oil-producing Loreto Region and incorporated evaluation of hydrocarbon voice mechanisms (prior consultation and environmental impact assessments) supported by interview testimony of stakeholders and state officials. PEV analysis reveals a political environment which is dangerous, inflexible, and intolerant of Peruvian stakeholders voicing over hydrocarbon development. This is due to the state’s zealous pursuit of its “selva (rainforest) hydrocarbon and development vision” which severely undermines Peruvian stakeholder’s freedom of voice.  相似文献   

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