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《The Professional geographer》2013,65(4):405-416
The oil refining and petrochemical industries have occupied an important role in Puerto Rico's development strategy since the early 1960s. However, the hopes epitomized in various planning models of highly integrated and diversified oil-based industrial complexes have not been fulfilled. This paper attempts to account for the discrepancy between official expectations and subsequent events in Puerto Rico and indicates some of the lessons for other developing countries. 相似文献
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《The Professional geographer》2013,65(4):343-349
Landowners can choose either to sell or to hold their land in areas with active rural land markets. Sellers and nonsellers are both important because their decisions shape patterns of land use. Analysis of mail survey data from 286 landowners in the Rochester, MN SMSA isolates four characteristics that distinguish sellers from nonsellers: occupation, size of landholding, recent acquisition of land, and interest in selling land. Nonsellers are often farmers with a large landholding and no interest in selling. More information is needed about their non-economic motives for holding land. 相似文献
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《The Professional geographer》2013,65(3):278-282
The effects of intra-farm distance on farm income have not been previously tested in North America. European studies are inconclusive as they use data taken from bookkeeping accounts for the farm as a whole. This paper calls for field-to-field farm analyses that combine internal movement costs with costs of production, yields, and farm-gate prices. In a study applying this method to Manitoba grain farms, it was found that adjustments in the organization and intensity of farming offset the effects of distance on net income. 相似文献
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《The Professional geographer》2013,65(3):270-276
Though urban planning issues continue to be created largely by local problems, urban theorists have become sensitive to the indirect modifying effects of federal urban policy on the local land-use structure. Federal tax policies on income derived from multifamily real estate appear to have generated excessive apartment construction during the 1968–73 period in Minneapolis-St. Paul suburbs. The consequence of these policies is evident in high multifamily suburban vacancy rates for Twin City apartments built during this period. 相似文献
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《Urban geography》2013,34(2):118-129
This article explores the historical, economic, and social factors that shape the recent migration of middle-class Blacks to low-income, urban, Black neighborhoods. It focuses on the meanings associated with this pattern of Black gentrification and the extent to which this residential pattern is consistent with previous models of urban gentrification. Using three years of ethnographic data from a low-income neighborhood in Philadelphia that has experienced an increase in Black middle-class residents, I conclude that this pattern of neighborhood change is distinct from previous models of urban gentrification. In this article, I argue that Black gentrification represents a unique set of opportunities and constraints that produce a group of middleclass African Americans willing to invest their social, economic, and cultural capital into improving the quality of life for low-income Black neighborhoods and their residents. 相似文献
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YehuaWei DepartmentofGeography UniversityofCalifornia LosAngeles LosAngeles CA USA 《地理学报(英文版)》1997,(1)
Citysizedistributionofnationalurbansystemshasattractedconsiderableresearchinterest.Theissueisalsocriticaltogovernmentpolicyasitisassociatedwithpopulationdistribution,unevendevelopment,andgeopolitics.Previousresearchefforthasgreatlyenhancedourunderstand… 相似文献
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CHARACTERISTICS OF Nd AND Sr ISOTOPES AND TRACE ELEMENTS FOR LATE CRETAEOUS VOLCANIC ROCKS IN KING GEORGE ISLAND, ANTARCTICA: IMPLICATIONS FOR SOURCE OF THE VOLCANICS FROM DEPLETED MANTLE 下载免费PDF全文
Rb-Sr isotopic isochron dating of the volcanic rock samples from the Upper Cretaceous Half Three Point Formation on the King George Island is 71.33±0.3 Ma. Correlative study of _(εND)(T)-~(147)Sm/~(144)Nd, ~(143)Nd/~(144)Nd-~(87)Sr/~(86)Sr, ~(87)Sr/~(86)Sr-Sr and ~(87)Sr/~(86)Sr-K_2O/(K_2O+Na_2O) indicated that the volcanic rocks were chiefly derived from the depleted mantle source and generally were not mixed crust materials. Of the samples 6 were given the mean Sm-Nd model age (T_(DM)~(Nd) of 443.3±20.6 Ma possibly indicating the age of chemical variation event in the magma source of the study area. Features of the trace elements indicated that the rocks from the Half Three Point Formation are of typical eale-alkaline volcanic suite and similar to those from the Tertiary volcanic rocks of the Fildes Peninsula, being the same products of the island-arc volcanic activity. 相似文献
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Zhang Qingsong 《地理学报(英文版)》1995,(2)
TheAnturCticisoneofthemostimpohantcoldsourcesonEarth,asabout24.5xlo'km'oficewhichtakes9opeamtoftotalicevolumeontheglobecoveronit.RotreaoradvanceOftheAntarcticIceSheetwillaffatfluCtuationofsealevel.ItiscalculatalthatiftheAntercticIceSheetlscomplotelymeltaw… 相似文献
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《The Professional geographer》2013,65(2):135-139
The co-ordinate system (x, y) for the triangular Christaller lattice is generalized by the addition of a third, dependent, z-axis. The extended system yields the lattice distances between lattice points, whereas the original system yields only the plane Euclidean distance. 相似文献
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《The Professional geographer》2013,65(4):403-409
Popper's concept of Worlds 1. 2, and 3 is discussed briefly in the light of idealism and materialism and to illustrate the debate about reification and reductionism. Then six types of change in geography are classified as changes in the phenomenal environment (World 1) and in that part of the behavioral environment that constitutes World 3. These changes involve those comparisons within or between “Worlds” that identify future research problems. 相似文献
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《The Professional geographer》2013,65(3):274-285
Local labor market policies of the federal government are critically evaluated with respect to their target efficiency and underlying theoretical assumptions. Policies of the Economic Development Administration are considered to be target inefficient compared to those of the Comprehensive Employment Training Act. Experimental mobility policies of the Department of Labor appear to be have questionable impact locally as opposed to nationally. Some local hybrid programs offer improved place and people targeting. 相似文献
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《The Professional geographer》2013,65(4):433-442
The need to protect high quality agricultural land through public policies and programs at various levels of government has been debated in the U.S. for at least three decades. This article reviews the evolution of the debate before 1979, the ill-fated attempt of the National Agricultural Lands Study (NALS) (1979–1981) to resolve the debate, and the current status of the land conversion issue. Articulation of the issue has been impeded by confusion of objectives, semantic problems, unreliability of land conversion data, and excess capacity in the American farm economy. Land conversion estimates published in 1977 by the Soil Conservation Service and relied upon by NALS have proven to be misleading in light of the 1982 National Resources Inventory. State and local programs to discourage farmland conversion are justifiable in terms of land use planning objectives, maintenance of a viable local farm economy, and avoidance of undue reliance upon marginal lands requiring costly technical inputs. 相似文献
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Cao Yong 《地理学报(英文版)》1994,(Z2)
1ntroductionSincel978ChinaembarkedonitsmodemiZaionprogramadopingtheopnDoorPOliCy.Sincethen,cooperationbe~nChinaandtheho-forificcountriesews)havebeenintensifiedandextensified.Noonlybilateraltradeactivitieshavebeenburgeoning,therehasalsobeenPhenomenatgrOWthinthedirectinvestmentineachothefseconomy.Besides,therehasbeenemergingsomenewtypesofmultinationalcoopefationtopromOtefullexploitationofmralandhumanresourcesandtoutilizeeachOther'scomParativeadvantags.TwoPedicularareaswhichmaybelookedaspoe… 相似文献
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Although dust storms rarely occur in southern California's deserts, blowing dust often reduces visibility, and large spatial and temporal variability in the frequency of blowing dust occurs throughout the region. On average only 1.3 dust storms occur in the study area each year. The annual average number of dust events (visibility <11 km) is 18.0, with the Coachella Valley being dustiest region, averaging 37.8 dust events each year. Mean annual frequencies of dust events for 1973–1994 are mapped, showing a core of activity centered over the Imperial/Coachella Valley region, with fewer dust events around the periphery of the study area. Most stations show a coherent temporal pattern of dust frequency during the period 1973–1994, with the mid-1970s experiencing the most dust. Blowing dust generally was absent from all stations during 1979–1983, 1987–1989, and 1992–1994. The mid-1980s were moderately dusty and 1990–1991 saw a return to very dusty conditions, possibly resulting from below-normal precipitation and increased anthropogenic disturbances. Dust events in the Mojave Desert characteristically occur during the winter to spring months (February-May), associated with dry frontal activity, and are largely absent during the dry summer months. The Colorado Desert experiences a similar seasonal distribution of dust events, but has more summer events, usually associated with convective thunderstorms. Frequencies of blowing dust have weak, but statistically significant, correlations with mean annual and antecedent precipitation, suggesting that complex processes control dust emission. [Key words: blowing dust, dust storms, Mojave Desert, Colorado Desert, wind erosion.] 相似文献
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