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Urban sprawl has become a global phenomenon as an outcome of growing population and rapid urbanization. Previous studies have addressed the rising incidence of uncontrollable urban development, particularly in peri-urban areas of cities, leading to chronic urban sprawl. The city of Guwahati, a million city in north east India, has expanded significantly in recent years. In this article, the links between population and growth of built-up areas were examined using geo-spatial techniques and remotely sensed datasets. The results indicate that the sprawl has accentuated in recent years. The intensity of land use remained uneven due to marked variations in the distribution of built-up areas, plausibly an outcome of unplanned urban growth. If current trends are anything to go by, future urban sprawl could pose serious threats to the vulnerable eco-sensitive and peri-urban areas of Guwahati. Secondary cities have unfortunately received scant attention in urban policy research, and Guwahati, epitomizes urban woes in a developing country. 相似文献
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Łukasz Wiejaczka Lakpa Tamang Danuta Piróg Paweł Prokop 《Environmental Earth Sciences》2018,77(20):718
The present study focuses on the Balason river running through the Himalayan piedmont zone (near Siliguri, India). The objective of the study is an assessment of the environmental effects of river bed material extraction by humans and the dependence of indigenous people on the river and its ecosystem services. The analysis is based on results of field work consisting of geodetic measurements of the river channel and interviews among the local community from the Nimtijot village. Historical hydrological data were also used for the study. The results of the investigation show that the Balason river is heavily affected by excessive exploitation of river bed material during dry season and the replenishment of extracted material in a monsoon season is not always sufficient. It leads to channel deepening. The local community working in the river heavily depends for its livelihood on continuing this activity. A decreasing amount of bed material to be extracted may lead to degradation of the strong relationship between the local community and their natural environment (river). 相似文献
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Sylwia Grabowska Jerzy W. Mietelski Krzysztof Kozak Paweł Gaca 《Journal of Atmospheric Chemistry》2003,46(2):103-116
The Petryanov air filters combined into half-year sets were analyzed for the presence of 40K, 137Cs and 22Na by means of low-background gamma rays spectrometry. Each sample contains aerosols from more than 1 Mm3 of air. Samples were collected in ground level air at Kraków (Southern Poland) from 1996 to 2002. Activity concentrations of 40K are almost constant with the mean of 14.7± 4.5 Bq m–3. Activity concentrations of 137Cs, which are on the level of single Bq m– 3 show exponential decrease with effective half-life time of 7.07± 0.77 years. The cosmogenic 22Na shows a strong seasonal variation with significant different mean values activity concentration between 0.333± 0.095 Bq m–3 and 0.137± 0.045 Bq m–3, for summer and winter, respectively. Moreover, the activity ratio for two cosmogenic radionuclides: 22Na and measured previously 7Be show also changes with statistically significant seasonal differences. The lower values were found during winters. The mechanisms which might govern this ratio are discussed. The conclusion is that transport of 22Na during summer seems to be so much effective, that results in kind of relative depletion of stratosphere of this nuclide. 相似文献
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The analysis of application of two dynamical models (``Earth–Moon' and``barycentre' model) in the motion of Near Earth Asteroids was performed. Mainaim was the quantitative estimation of the influence of lunar perturbations on the motionof NEA. Additionally, basic tests of application of numerical methods weremade (RMVS3 and B–S methods). The orbits of 1083 Apollo–Aten–Amor and 7selected AAA objects were adopted as test particles in numerical integrationof the motion. The comparison between results obtained by both dynamicalmodels is discussed in detail. In specific cases, the application of the``Earth–Moon' dynamical model is very important and cannot be neglected incomputations of orbits. 相似文献
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Lightning discharges monitored by the SAFIR network system in Poland have been additionally identified over the 100×100 km
area near Warsaw by single-point independent recordings of electric field and Maxwell current rapid changes. The data collected
in summer thunderstorm days of 2002 showed some untypical properties of the lightning discharges which are rarely observed.
Especially remarkable was a number of ground multi-stroke flashes with the return strokes (RS) which transported to the earth
charges of opposite signs. Bipolar flashes (BF) of this kind were mostly involved in the events in which the nearby intracloud
(ic) and cloud-to-ground (c-g) discharges were very closely associated in time. Events of such a close collocation of two
different types of lightning discharges, previously called the complex lightning discharge events (CLDE), were quite often
observed during summer thunderstorms in Poland.
The events of this kind, i.e. 8 flashes, identified by the SAFIR detection system as BF’s present the multiple stroke flashes
of the mean horizontal separation distance between striking points of particular RS equal to (2.8 ± 2.1) km and of the mean
time interval between strokes of (46.8 ± 74.4) ms. The time separation between the observed BF and the adjacent ic flashes
was from 0.1 to 335 ms, and horizontal separation distance between them ranged from 1.8 to 14.5 km. The multiplicity of the
recorded BF’s ranged from 2 to 4 strokes. Four of these BF’s followed the ic discharge, but the other three preceded the ic
and one was alone with no close ic. 相似文献
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In this paper we present a new method of restoration of the true three-dimensional (3D) trajectories of prominence knots using
ground-based observations taken with a single telescope that is equipped with a Multi-Channel Subtractive Double Pass imaging
spectrograph. Our method allows us to evaluate the true 3D trajectories of the prominence knots without any assumptions concerning
the shape of the trajectories or the dynamics of the motion. The reconstructed trajectories of several knots observed in three
prominences are presented. 相似文献
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Żelaźniewicz Andrzej Dörr Wolfgang Bylina Paweł Franke Wolfgang Haack Udo Heinisch Helmut Schastok Janina Grandmontagne Klaus Kulicki Cyprian 《International Journal of Earth Sciences》2004,93(5):773-781
We report U–Pb single zircon ages from three pre-Variscan granitoids in the NE part of the Bohemian Massif. The Platerówka granodiorite from the Lausitz-Izera Unit, the Polish Sudetes, has been dated at 533±9 Ma. The Bitouchov granite form the SW part of the South Krkonoe Unit, the Czech Sudetes, gave an age of 540+11/–10 Ma, and the Wdroe granodiorite in the Fore-Sudetic Block yielded 548±9 Ma. All these latest Vendian/Early Cambrian granitoids represent the post-tectonic expression of a late Proterozoic Cadomian orogenic cycle and demonstrate the eastward extent of the Cadomian basement into the Variscan orogen. Granodiorites of similar age have so far been reported from Brittany and especially from the Saxo-Thuringian Terrane to the NE and SW of the Elbe Fault Zone. We conclude that the Saxo-Thuringian Terrane extends across the Elbe and Sudetic Marginal Fault Zones into the Fore-Sudetic Block. 相似文献
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In this paper we consider the buying/selling prices of carbon dioxide (CO2) emission permits in trading models with uncertainty. Permission prices, although usually omitted from standard models, may significantly influence the trading market. We thus undertook to construct a more realistic trade model and to compare it with the standard one. To do this, we introduced several important changes to the standard model, namely, (1) a new optimized quality function; and (2) transactions with price negotiations between regions. We also enhanced the model using methods described in the literature to allow it to deal with reported emissions uncertainty. Additionally, we used an original method of simulating this kind of market based on a specialized evolutionary algorithm (EA). 相似文献
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Natural Resources Research - Catastrophic cases of methane explosion during exploratory drilling within the Be?chatów ortholignite deposit have led to testing for methane in other Polish... 相似文献