Quantification of urban expansion in Siliguri urban agglomeration (UA): a model-based approach

In the study of new towns and cities, spatial assimilation and the complex nature of urban development hold issues of special importance. At present, in developing countries like India, rapid development as well as urbanization in medium sized cities is a noticeable phenomenon. However,researchers in the field of urban study,lay emphasis on larger cities in our country. Therefore,more studies are essential to identify the problem and future prospect and also to suggest satisfactory policies for the betterment of medium sized cities.The current paper assesses the spatial expansion of the Siliguri (a fast growing medium sized city of Eastern India) designed for the year 1990, 2000, 2010 as well as 2019 using satellite imagery and field investigation.The research quantifies the urban growth and sprawling pattern in the study area using statistical techniques and spatial matrices.The other objectives of this study are to predict and analyze the urban growth of Siliguri Urban Agglomeration (UA) of 2030 with the help of a Future Land Use Simulation (FLUS) model. This simulation model was chosen by using a technique to evaluate the classified images in three maps: a time 1 reference map, a time 2 reference map and a simulation map of time 3. Spatial metrics and Shannon entropy results revealed that Siliguri (UA) is experiencing rapid sprawl. In contrast, the degree of freedom results revealed a significant gulf between the observed and planned urban development.The simulation model also showed that the unsustainable trend will likely to remain intact in the future, with the built-up area rising to 78.496 km² by 2030, potentially resulting in loss of major cultivated land, fallow land and flora.

     

Patterns of population change in Ghana (1984–2000): urbanization and frontier development

The study addresses population dynamics in Ghana on the urban and regional levels between 1984 and 2000. At the urban level, the development trends are analyzed for urban localities (population above 5,000) on the basis of geo-coded census data. Potential driving forces for rapid population growth related to size, location, accessibility and facility counts are examined using bivariate and multivariate analysis. An index of weighted accessibility relative to other urban localities provides significant explanation at the national level, as does initial locality size. At the regional level, population development is analyzed to provide insight into the rural–urban relations. The level of urbanization is steadily increasing but varies considerably between regions. Areas of high population growth are found in some rural areas that have a remote location relative to the large urban centers. This seems to indicate the existence of ‘frontier’ regions, i.e. areas that experience a high degree of in-migration by people aiming to undertake specific farming activities. A high proportion of the population growth in these areas appears to take place in relatively small towns. The paper concludes with a more in-depth discussion of the development characteristics of Ghana’s Western Region. This region has experienced one of the highest regional population growth rates, mainly due to its status as a ‘frontier’ for cocoa production.

Urban-rural relationships in India: a macro-scale approach using population potentials

The urban system in India is the product of a long and complex history and the urban-rural dichotomy is marked. While urban India is often viewed as ‘modern’ and ‘commercial’, rural India is generally characterised as myopic, backward and traditional. The diffusion of a modern commercial sector into traditionally agricultural areas is seen to be slow because of the lack of small sized towns, and many of the major cities are viewed as the centres of introverted economic systems. This paper seeks to examine these aspects of urban-rural relationships and levels of development in India at two scales, the national and the district. The national scale study analyses the urban and rural components of population potential surfaces. The study at the district level uses similar data, but at a finer scale, and in addition considers potentials of retail trade which gives a clearer illustration of ‘importance’ than population data alone. Several innovations in technique are discussed. The paper concludes with some general methodological comments about the nature of location as perceived by geographers.     

近20年来长江经济带生态环境变化

长江经济带发展战略实施以来,长江上、中、下游地区经济快速发展,与此同时,生态系统不可避免受到扰动,长江经济带生态环境状况面临压力,亟需开展长江经济带生态环境质量评价.本文选取2001年和2020年MODIS和Landsat遥感影像计算湿度、绿度、干度、热度4个评价指标,通过主成分分析方法计算遥感生态指数RSEI,对长江...     

Middle Pleistocene large‐mammal faunas from North Iberia: palaeobiogeographical and palaeoecological implications

The rich Quaternary fossil record from the Cantabrian region (NW Iberia) is virtually restricted to the Late Pleistocene, with Middle Pleistocene findings very rare. This work presents the study of two Middle Pleistocene palaeontological sites in the Cantabrian region: Llantrales quarry and Mestas de Con mine, both discovered and first described in the 1950s but never studied in detail thereafter. The material was here re‐analysed and re‐evaluated. Taxonomic attributions have been changed in most cases and, consequently, chronological assignments of the fossils have also been changed. This first detailed study of the assemblage from Llantrales quarry revealed the occurrence of the large‐sized deer Praemegaceros solilhacus, which has never been reported previously in North Iberia. Cervus cf. elaphus and Stephanorhinus cf. hundsheimensis were also identified. The age of these fossils was originally regarded as Pontian (late Miocene), but new palaeontological results indicate a much younger age, most likely from around 0.8 to 0.5 Ma. A taxonomic re‐evaluation of the fossils from Mestas de Con provided different results with respect to the 1950s works. The faunal association is composed of a large‐sized deer (probably corresponding to Praemegaceros), Cervus elaphus, Capreolus cf. capreolus, Bison sp. (small sized), Equus sp. (large sized), Stephanorhinus hemitoechus, Ursus sp. and Homotherim latidens. This faunal association was evaluated within a western European context and proves to be highly analogous to other contemporary assemblages there. The chronology was initially regarded as late Villafranchian (in a broader sense). New results, documenting the co‐occurrence of Stephanorhinus hemitoechus and Homotherium latidens, indicate a more precise and younger age, most likely between 0.6 and 0.4 Ma. These two fossil assemblages provide new and relevant information on the Middle Pleistocene faunas from a geographical region where this information, compared with other western European areas, is rare and poorly known.     

Rural settlement change in the Republic of Ireland — a preliminary discussion

One of the notable repercussions of the population stability and growth in Ireland in the past two decades has been the impact on settlement in rural areas. Rural areas in the vicinity of towns and cities especially have experienced this urban-generated settlement expansion. This preliminary examination looks at the changes which have taken place in rural settlement patterns and briefly discusses their implications.     

Holocene small mammals hunted by owls and humans in southern Brazil: taphonomic evidence and biological significance

Understanding resource utilization and economic diversification amongst Holocene hunter‐gatherers in southern Brazil requires in‐depth taphonomic analysis of faunal assemblages. Three Early to Late Holocene archaeological sites (Garivaldino, Pilger and Sangão) in Rio Grande do Sul State, southern Brazil, revealed large assemblages of small mammal (?1 kg) remains, composed mainly of rodents. To appreciate depositional processes of fauna in relation to human consumption, taphonomic attributes and processes were evaluated. The results indicated that the remains accumulated through different antemortem taphonomic pathways, apparently linked to the size and natural history of the species represented. The small‐ and medium‐sized (<150 g) cricetid rodents (e.g. Pseudoryzomys simplex and Sooretamys angouya) were represented by a low proportion of teeth with lightly digestive corrosion suggesting that they were derived from the predatory activity of owls, possibly Tyto alba. In contrast, large‐sized cricetids (>150 g; Kunsia tomentosus, Gyldenstolpia sp. and Holochilus sp.), and several caviomorph rodents with aggregated spatial distributions (Echimyidae (?Dicolpomys fossor, Phyllomys sp., ?Clyomys riograndensis and ?Euryzygomatomys mordax), Caviidae (Cavia sp.) and Ctenomyidae (Ctenomys sp.)) showed evidence of thermoalteration patterns and cut marks on bones, suggesting human exploitation. A postmortem depositional environment was deduced from dendritic and branched patterns of rootlet etching, apparent mostly at Garivaldino and Pilger. Polished areas and holes on bone surfaces, and impregnation of manganese showed moderate (Sangão) or low (Garivaldino and Pilger) incidence, pointing to water transport under moderate (Pilger) and low (Garivaldino and Sangão) energy over short distances. The results obtained here provide the first clear evidence of early human exploitation of small mammals in southern Brazil, suggesting a diversification of economies. In addition, as several of the recorded rodents are today regionally or biologically extinct, a preliminary discussion about the potential impact of humans on this process is provided.     

Potential suitability for urban planning and industry development using natural hazard maps and geological–geomorphological parameters

During the planning of an urban environment, usually only economic and social parameters are taken into account. As a result, urban areas are susceptible to natural disasters, which cause extensive damages in them, because the cities or towns have been repeatedly located in vulnerable areas. In this study, for the protection of human environment, is proposed a unique approach of urban planning and sustainable development. The study area is Trikala Prefecture (Western Thessaly, Central Greece). An integrated evaluation of the suitable areas for urban growth and light industry development is proposed by using mainly natural hazards as well as geological–geomorphological–geographical characteristics of the study area. The used parameters were correlated by using the analytical hierarchical process (AHP) method and incorporated into a geographic information system (GIS) in order to produce the corresponding suitability maps. The study area is classified in five categories of very high, high, moderate, low, and very low suitability for urban growth and industrial development. Moreover, the spatio-temporal changes of the urban limits are studied since 1885 for the three major towns (Trikala, Kalambaka and Pyli) of the study area. These changes sketch out the urban growth trend. The comparison between the urban growth trend with the potential suitability for urban growth and industrial development of these towns lead to discrepancies. These can be attributed mainly to the fact that in the majority of cases, only geographical, social, and economical factors were used for urban development, whereas in our study, natural hazards, geomorphological, and geographical parameters were quantified and taken into account.     

Growth trends and changes in small towns in Saudi Arabia (1974–1993)

This study examines some of the factors affecting growth and change in small towns in Saudi Arabia (1974–1993), namely, their relative location and population size. The study hypothesizes that small town's rate of growth increases with distance from the nearest large city and that small towns' having larger population in 1974 will likely be the ones to grow more in 1993. The research data were obtained from population censuses of 1974 and 1993. Findings indicate that there is a positive but low association between small towns population growth rate and distance from the nearest large city and a strong negative relationship between growth rate and town population size.     

Outstations to primacy: Economic policy,class formation and growth in the towns of Papua New Guinea

Most towns in Papua New Guinea are small and the hierarchy comprises many isolated outstations and small towns. As a response to changes in economic policy the largest towns are growing rapidly at the expense of the small service centres. Changes in the population structure of these large towns have resulted in high rates of natural increase, while rural urban migration is steadily bringing in newcomers, to face urban unemployment and a lack of adequate housing. A secondary urban problem arises from the colonial legacy of urban zoning, which exacerbates the housing shortage and has created artifical socioeconomic residential areas. Although social differences are relatively small, the policy of economic growth will increase the gap between rich and poor, while urban unemployment and lack of housing have reached a crisis level in the rapidly growing big towns.     

The areal conditions,bases and differences of the rural urbanization in China's Coastal Development Region

This paper analyzes the regional base for urbanization in rural areas of the Coastal Development Region: the natural conditions; the historical changes, and present-day levels and characteristics of the development of the economy, population, cities and towns.The internal differentiations of the Coastal Development Region are characterised as the general differences between the North and the South of China; The three gradations of the economic development level between the coastal provinces are similar to the differences between the provinces and autonomous regions of the whole country; open areas have been introduced, into this region.     

Fine particle deposition to initially starved,stationary, planar beds

Reported here are results from new flume experiments examining deposition and entrainment of inert, silt‐sized particles (with spherical diameters in the range from 20 to 60 μm) to and from planar, impermeable and initially starved beds underlying channel flows. Bed surfaces comprised smooth or fixed sand‐size granular roughness and provided hydraulically smooth to transitionally rough boundaries. Results of these experiments were analysed with a simple model that describes the evolution of vertically averaged concentration of suspended sediment and accommodates the simultaneous delivery to and entrainment of grains from the bed. The rate of particle arrival to a bed diminishes linearly, and the rate of particle entrainment increases by the 5/2 power, as the value of the dimensionless Saffman parameter S = u_*³/g’ν approaches a threshold value of order unity, where u is the conventional friction velocity of the turbulent channel flow, g’ is the acceleration due to gravity adjusted for the submerged buoyancy of individual particles and ν is the kinematic viscosity of the transporting fluid. This transport behaviour is consistent with the notion that non‐cohesive, silt‐sized particles can neither reach nor remain on an impermeable bed under flow conditions where mean lift imposed on stationary particles in the viscous sublayer equals or exceeds the submerged weight of individual particles. Within the size range of particles used in these experiments, particle size and the characteristic size of granular roughness, up to that of medium sand, did not affect rates of dimensionless arrival or entrainment to a significant degree. Instead, a new but consistent picture of fine‐particle transport is emerging. Silt‐sized material, at least, is subject to potentially significant interaction with the bed during intermittent suspension transport at intermediate flow speeds greater than the value required for initiation of transport (ca 20 cm sec^?1) but less than the value (ca 50 cm sec^?1) required by the Saffman criterion ensuring transport in fully passive suspension or, equivalently, ‘wash‐load’.     

European quaternary refugia: a factor in large carnivore extinction?

The extinction of large carnivores in Europe during the Quaternary is reviewed and the potential role of glacial refugia in these extinctions is investigated using the VORTEX model for population viability analysis. A model was built for a medium sized big cat similar to the extinct Panthera gombaszoegensis utilising life history data from the modern jaguar Panthera onca. This approach highlighted the potential importance of glacial refugia in the extinction process. Even model refugia the size of the Italian peninsula did not guarantee persistence of a population over a 1000 yr time span, illustrating the role of chance in survival in such a refugium. An area the size of the largest Mediterranean island was unable to support a big cat population for a period of 1000 yr. The models also demonstrated the importance of inbreeding as a mechanism for extinction in refugia. It is suggested that repeated genetic bottlenecks during successive glaciations would tend to remove lethal recessive alleles from the population, increasing the probability of survival in refugia in subsequent glaciations. The history of extinction of large carnivores in the European Quaternary is interpreted in the light of these results. Copyright © 2002 John Wiley & Sons, Ltd.     

An age-structured population model for horseshoe crabs in the Delaware Bay area to assess harvest and egg availability for shorebirds

The objective of this simulation study was to create an age-structured population model for horseshoe crabs (Limulus polyphemus) in the Delaware Bay region using best available estimates of age-specific mortality and recent harvest levels. Density dependence was incorporated using a spatial model relating egg mortality with abundance of spawning females. Combinations of annual female harvest (0, 50, 100, and 200 thousand), timing of female harvest (before or after spawning), and three levels of density-dependent egg mortality were simulated. The probability of the population increasing was high (>80%) with low and medium egg mortality and harvest less than 200 thousand females per year. Under the high egg mortality case, the probability of the population increasing was <50% regardless of harvest. Harvest occurring after spawning increased the probability of population growth. The number of eggs available to shorebirds was highest when egg mortality was lowest and female abundance was at its highest levels. Although harvest and egg mortality influenced population growth and food availability to shorebirds, sensitivity and elasticity analyses showed that early-life stage mortality, age 0 mortality in particular, was the most important parameter for population growth. Our modeling results indicate areas where further research is needed and suggest effective management will involve a combination of harvest management and actions to increase early juvenile survival.     

Development of human ecology in Lapland,Finland, after World War II Die Landesentwicklung in Finnisch-Lappland seit dem II. Weltkrieg Développement écologique de la Laponie Finlandaise après 1945

Everywhere in the industrially advanced world, a fundamental feature of the population trend has been a movement from the countryside into towns and from sparsely settled regions into previously densely inhabited areas and cities. In Finland a region that is being deserted is the province of Lapland. The development of its economic life after World War II has been studied. This war cut short the vigorous growth experienced by the province in the previous decades, but its aftermath inaugurated a period of reconstruction and state-supported measures that for a short time enlivened economic activity there and brought about optimism as to future prospects. The short-sightedness of the developmental measures and, to some extent, the lack of planning behind them have later become evident; the promising rise of economic activity has now halted or turned downward in nearly every field of endeavor.     

Maritime impacts on the littoral organization — The case of the Western Mediterranean

Littoral life in the W Mediterranean is undergoing relevant changes. There are about 40 seaports in thh are, making up a sort of Southern Range (from Algesiras to Leghorn), and besides that a South-Western Area (Italian Mezzogiorno), and a Developing Area (African coast). A new spatial model of oil transport — the third one sinnce the Sixties — is emerging, having a high degree of freedom. Growing consumption of steam coal brings about the construction of deep-sea terminals generating feeder effects within the Mediterranean. In unitized transport the Mediterranean has weaker relations with Europe than with non-European areas, and brings about the construction of platforms for the distribution of containers. NW industrial areas are being transformed and concentrations of new tertiary activities are emerging, relations between littoral cities and inland cities are changing, medium ports are coming to the fore. Relations between W and E Mediterranean shores are changing.     

Small town growth and development policy in Pakistan

This study examines the process of small town development and growth in Pakistan. It has been found that small towns located in the agriculturally developed areas have better opportunities for development than those that lie in less developed agricultural areas. Although government economic development policies have influenced the location and development of small towns, local leadership plays an important role in the socioeconomic development of small towns.     

Synchronous deposition of massive sulphide deposits in the Iberian Pyrite Belt: New data from Las Herrerías and La Torerera ore-bodies

Two small to medium sized massive sulphide deposits, Las Herrerías and La Torerera, located in the Iberian Pyrite Belt (IPB) are examined from a geological and palynostratigraphic perspective. The palynological assemblages are assignable to the Retispora lepidophyta–Verrucosisporites nitidus (LN) miospore Biozone (Latest Devonian: Latest Famennian/Strunian) of Western Europe. This age permits correlation with some of the main massive sulphide deposits dated so far in the region (viz., Tharsis, Aznalcóllar, Sotiel-Coronada or Neves-Corvo), and validates once again the hypothesis that a single mineralizing event was responsible for the genesis of most of the IPB’s massive sulphide deposits. The present study confirms that palynostratigraphy is an invaluable high-resolution biostratigraphic tool in the IPB, applicable to dating, correlation and ore-exploration.     

Zonation of the landslide hazards in the forereservoir region of the Three Gorges Project on the Yangtze River

On the basis of the investigation and statistic analysis of the landslide hazards in the forereservoir region of the Three Gorges Project on the Yangtze River, the major factors that are found to have affected the slope stabilities are outlined, and a zonation of landslide hazards of the region is made using an integrated information model. It is divided into destructive, disastrous, slightly disastrous, likely disastrous and essentially non-disastrous areas. The first two cover an area of less than 5% of the total region, and are at a distance of more than 20 km from the Three Gorges dam, and so a landslide over there will impose no direct impact to the TGP, but may effect to some degree the navigation of the Yangtze River and nearby highway transportation, reservoir slopes, and building of cities and towns.     

Evaluation of liquefaction potential hazard of Chennai city, India: using geological and geomorphological characteristics

According to the latest UNFA Report on state of world population 2007, unleashing the potential of urban growth by 2030, the urban population will rise to 5 billion or 60?% of the world population. Liquefaction in urban areas is dangerous phenomenon, which cause more damage to buildings and loss of human lives. Chennai, the capital city of the State Tamil Nadu in India, is one of the densely populated cities in the country. The city has experienced moderate magnitude earthquakes in the past and also categorized under moderate seismic hazard as per the Bureau of Indian Standards (BIS in Criteria for earthquake resistant design of structures; Bureau of Indian Standards, New Delhi, 1893 2001). A study has been carried out to evaluate the liquefaction potential of Chennai city using geological and geomorphological characteristics. The subsurface lithology and geomorphological maps were combined in the GIS platform for assessing the liquefaction potential. The liquefaction hazard broadly classified into three categories viz., liquefaction likely, possible and not likely areas. Mainly, the liquefaction likely areas spread along the coastal areas and around the river beds. The rest of the areas are liquefaction not likely and possible. The present map can be used as first-hand information on regional liquefaction potential for the city, and it will be help to the scientists, engineers and planners who are working for future site-specific studies of the city.