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21.
It is over 30 years since the concept of community without propinquity was first proposed. According to this concept, communities might be spatially far-flung, but nevertheless close-knit, intimate and held together by shared interests and values, rather than by geographical proximity. Although the idea of community without propinquity has been heavily criticised, the advent of advanced telecommunications and the emergence of cyberspace mean that a reappraisal of the concept, and of the changing nature of community generally, is warranted. The paper undertakes such a reappraisal. A review of the literature on cyberspace reveals several reasons why the social effects of advanced telecommunications and the Internet might be less than is sometimes predicted. Setting this discussion in the context of other social science discourses on new urbanism, consumption rather than production as a basis for city life, postmodernism, and 'the third way' in politics, shows that place and local community are, and will continue to be, fundamental to the functioning of society. Cyberspace might have annihilated distance but not place.  相似文献   
22.
The history of the development of Rossby-Number Similarity Theory for the neutral Planetary Boundary Layer (PBL) is reviewed. It is shown that the logarithmic profile derived by asymptotic matching is only valid in the matched layer and not in the surface layer proper. Derivation of the traditional PBL Resistance Laws from the theory is outlined. A best-fit polynomial through observations of geostrophic drag coefficients suggests that the traditional form of the Resistance Laws is inadequate. A new formulation is derived from a generalization of the theory that allows the logarithmic form of the wind profile in the matched layer to differ from that in the surface layer. This new formulation is evaluated against observations made during the 1967 Wangara Experiment. Finally, it is demonstrated how wind speed and wind shear profiles that are consistent with the new Resistance Laws may be obtained.  相似文献   
23.
We have characterized the internal structure of two close-to-round starless cores in Taurus, L1498 and L1517B, setting constraints on the initial conditions of star formation and on models of core condensation. Our analysis is based on high angular resolution observations in at least two transitions of NH3, N2H+, CS, C34S, C18O, and C17O, together with maps of the 1.2 mm continuum. For both cores, we derive radial profiles of constant temperature and constant turbulence, and density distributions close to those of non-singular isothermal spheres. Using a Monte Carlo radiative transfer model, we derive abundance profiles for all species and find a pattern of strong chemical differentiation. NH3 has a higher abundance toward the core centers while N2H+ has a constant abundance over most of the cores. Both C18O and CS (and isotopomers) are strongly depleted in the core interiors, most likely due to their freeze out onto cold dust grains. Concerning the kinematics of the dense gas, we find (in addition to constant turbulence) a pattern of internal motions at the level of 0.05 km s?1. These motions seem correlated with asymmetries in the pattern of molecular depletion, and we interpret them as residuals of core contraction. Their distribution and size suggest that core formation happens in rather irregular manner. A comparison with supersonic turbulence models of core formation shows that our observed cores are much more quiescent than allowed by these models.  相似文献   
24.
Several researchers have argued that Australia is becoming more unequal. This paper briefly explores the reasons why this might be the case before undertaking a social indicator based examination of whether income inequality extends to well‐being generally. Using 176 regions and eight social indicators and focusing on the period 1976–91, the paper shows that inequality has increased, particularly in the last intercensal period. The pattern of ‘winning’ and ‘losing’ is a complex one that suggests increasing differentiation between regions. This finding is set in the context of the social differentiation inherent in postmodern society. Regional policy based on the devolution of spending and responsibility is advocated as one way of helping disadvantaged regions.  相似文献   
25.
This is one of a series of papers on the Askervein Hill Project. It presents results on the variations in mean wind speed at fixed heights (z) above the ground from linear arrays of anemometer posts and towers. Most of the data are for z = 10 m but some are for z = 3 m. Selected and directionally grouped data from the 55 Mean Flow runs are presented together with mean flow data from Askervein '83 Turbulence runs. Comparisons are made between the data and guideline estimates of fractional speed-up ratio at hilltop locations and between the data and MS3DJH/3 model predictions along the tower lines. There is good agreement in most cases.  相似文献   
26.
International tourist flows to Australia are examined from the perspective of globalisation. The factors influencing such flows are identified and their geographical impact outlined. Inbound tourism is shown to be growing quickly in both absolute and relative terms and to have a metropolitan emphasis that contrasts with the non‐metropolitan focus of domestic tourism. Tourism illustrates many of the social and cultural changes occurring in contemporary society; the nature of tourism is changing as society changes with a result that new forms of tourism are emerging. Particularly noteworthy is the shift from mass to ‘new tourism’. The nature and likely impact of these changes in Australia is assessed. The paper concludes that growth rates comparable with those achieved in the past might not be sustainable.  相似文献   
27.
The notion of sponge cities has attracted considerable attention in the media, in the policy arena, and in academia. It rests on the notion that some regional centres ‘soak up’ population and business from a ‘pool’ of surrounding areas, thereby appearing as ‘oases’ of growth in areas of population decline. Specifically, the notion of sponge cities rests on two premises and a deduction: some large towns and provincial cities are growing; surroundings areas are losing population; therefore, the growth results from the relocation of people from outlying farms and smaller towns to the nearby growing centres. Despite its popularity, the notion has largely gone untested. Investigation of migration trends in Dubbo and Tamworth (New South Wales, Australia), frequently cited as sponge cities, over the period 1986–2001 shows that the reality is much more complex than the simple metaphor suggests. The contribution made by the ‘pool’ to the growth of the regional ‘sponges’ is relatively minor. This calls into question the value of the notion of a sponge city—and the use of metaphors in social science more generally.  相似文献   
28.
Land-based meteorological measurements at two locations on the Danish coast are used to predict offshore wind speeds. Offshore wind-speed data are used only for developing the statistical prediction algorithms and forverification. As a first step, the two datasets were separated into ninepercentile-based bins, with a minimum of 30 data records in each bin. Next, the records were randomly selected with approximately 70% of the data in each bin being used as a training set for development of the prediction algorithms, and the remaining 30% being reserved as a test set for evaluation purposes. The binning procedure ensured that both training and test sets fairly represented the overall data distribution.To base the conclusions on firmer ground, five permutations of these training and test sets were created. Thus, all calculations were based on five cases, each one representing a different random selection from the same data, but maintaining the (approximate) 70-30 split in each bin. This procedure served to ensure that conclusions were not based on a single randomly-selected case. Two statistical methods are employed:multiple linear regression (MLR), and Classification and Regression Trees(CART). MLR produces excellent results using only land-based predictors.The CART results are similar to those from MLR, and tend to be slightly better.Retired  相似文献   
29.
Our experience in applying earlier versions of a model of boundary-layer flow over low hills to real terrain (see Walmsley et al., 1982) has led to the development of a new version which we designate MS3DJH/3. The main improvements are the use of terrain-dependent length and velocity scales and the blending of inner and outer layer results into a single universally valid solution for the velocity perturbation field. MS3DJH/3 was carefully calibrated against alternative computations of flow over idealized two-dimensional terrain features using more detailed models prior to its application to real, three-dimensional terrain. It still provides high spatial resolution with low computing cost and is applicable to flow over terrain features with horizontal scales from 10 m to 10 km.Contractor: 24 Heslop Drive, Toronto.  相似文献   
30.
Personal construct theory was used to study the appraisive images held by tourists visiting the North Coast of New South Wales. In the first stage of the research, subjects produced a wide variety of constructs in differentiating between tourist places. This enabled the identification of six key evaluative constructs. In the second stage of the research, these constructs were incorporated into repertory grids that revealed how places were viewed. Principal components analysis showed that very similar images were held by tourists irrespective of age and sex, but that slight differences emerged between the images held by tourists and those held by workers in the tourist industry. The evaluative constructs identified may provide a general basis for understanding tourist perceptions.  相似文献   
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