Mathematical models for pollutant transport in semi-infinite aquifers are based on the advection-dispersion equation (ADE) and its variants. This study employs the ADE incorporating time-dependent dispersion and velocity and space-time dependent source and sink, expressed by one function. The dispersion theory allows mechanical dispersion to be directly proportional to seepage velocity. Initial...

the present study illustrates the long-term changes in selected socioeconomic variables (population,industrial activities, settlement dispersion, and land-use) together with climate aridity trends in thriasio, the larger industrial area of greece located twenty kilometers far from athens. this region, originally devoted to agriculture, experienced fast industrial and economic development during...

There are several alternative hypotheses about the effects of territoriality, kinship and prey availability on individual carnivore distributions within populations. The first is the land-tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance. The second is the kinship hypothesis, which predicts related individuals will be clumped ...

We propose extreme value analogues of natural exponential families and exponential dispersionmodels and introduce the hazard slope as an analogue of the variance function. The set of quadraticand power hazard slopes is characterized, and is shown to include well-known distributions such asthe Rayleigh, Gumbel, power, Pareto, logistic, negative exponential, Weibull and Fréchet famili...

bionomics of aphis gossypii glover and its predators coccinella septempunctata l. and hippodamia variegata goeze were studied in varamin (tehran province) during 11th may to 5th october 2006 on eggplant crop, with the interaction (density dependence) between the aphid and either of the predators determined. the reliable sample size (number of leaves) with a maximum variation of 6.73% was about ...

the complexity of urban systems in our recent world, make it difficult to evaluation and explanation of their changes with traditional and customarily methods. in the past, remote sensing has shown an ability to detect and describe urban growth patterns at different spatial scales. with new remote sensing devices (e.g. ikonos), with innovative image processing techniques and with further develo...

forest ecosystems that have spent a long time to mature, offer important goods and services to humanity. hence, utilization and exploitation of these resources should be based on careful assessment of their ecological value and potential. ecological land evaluation is an approach based on land quality, vulnerability and potential assessment for different acceptable uses drawing upon related mod...