Evaluating the Long-term Urban Expansion of Ranchi Urban Agglomeration,India Using Geospatial Technology

The present study analyzes the built-up expansion of Ranchi urban agglomeration over a period of about 8 decades from 1927–2005. Satellite images and topographical maps were used to evaluate land use dynamics during these periods. Built-up growth of 473.7% during 1927–2005 was primarily at the expense of agricultural land along with reduction of natural water bodies reflects negative impacts of built-up expansion, which increased many folds in recent decades. The built-up growth is also analyzed with reference to population growth, land consumption rate and land transformation. The land loss due to increasing built-up growth of Ranchi were compared with other capital regions and cities along with population increase to provide insight into the possible scenario of built-up expansion in Ranchi urban area.     

Burdigalian–Serravalian calcareous nannoplanktons from Qom Formation, North-Center Iran

The aim of this study is to determine calcareous nannofossil species found in Kamar-Kuh area and demonstrate this use for biostratigraphic studies. The Qom Formation is widely distributed in Kamar-Kuh section and has nine members(a–f). In this study, 12 samples were taken and prepared with smear slide. Some of the determined species are listed below, and some of them are photographed by light and scanning microscope. According to obtained nannofossils, 16 species, nine genera, and six families were determined. Obtained nannofossils indicated age of Burdigalian–Serravalian (middle Miocene) for this section.     

Extinction and biogeography of birds on huahine,society islands,French polynesia

This study is based upon the identification of 336 bird bones from the Fa'ahia archaeological site, Huahine, French Polynesia. The bones represent birds that were killed for their flesh, feathers, or bones by prehistoric Polynesians. The radiocarbon ages of excavated strata at Fa'ahia range from about 1140 ± 90 to 770 ± 90 yr B.P. The bird bones represent 15 species of resident seabirds, 15 species of resident landbirds, four migrant species, and one introduced species. The only extinct seabird is a gull, Larus new species, although locally extirpated seabirds are Puffinus pacificus, Puffinus nativitatis, Puffinus lherminieri, Pterodroma rostrata, Pterodroma alba, Pterodroma arminjoniana, Sula leucogaster, Sula sula, Fregata minor, Fregata ariel, and Anous minutus. Extinct landbirds are Gallirallus new species, Gallicolumba nui, Macropygia arevarevauupa, Vini vidivici, Vini cf. sinotoi, and Aplonis diluvialis. Locally extirpated landbirds are Ardeola striata, Porzana tabuensis, Gallicolumba erythroptera, Ducula galeata, Ducula aurorae, and Acrocephalus caffer. The bones from Fa'ahia increase the seabird and landbird fauna of Huahine, from the historically known 3 to 15 species and from 7 to 18 species, respectively. Thus the number of species from Huahine is even greater than those from nearby Tahiti, which has a much greater land area and elevation. The occurrence of so many extinct or extirpated species of birds at the Fa'ahia site suggests that this site represents a very early phase of human occupation on Huahine, probably no more than 500 years after the first arrival of people on this previously undisturbed island ecosystem.     

Assessing issues associated with a time‐integrated fluvial fine sediment sampler

Collecting a representative time‐integrated sample of fluvial fine‐grained suspended sediment (<63 μm) is an important requirement for the understanding of environmental, geomorphological, and hydrological processes operating within watersheds. This study (a) characterized the hydrodynamic behaviour of a commonly used time‐integrated fine sediment sampler (TIFSS) using an acoustic Doppler velocimeter (ADV) in controlled laboratory conditions and (b) measured the mass collection efficiency (MCE) of the sampler by an acoustic Doppler current profiler under field conditions. The laboratory results indicated that the hydrodynamic evaluations associated with the original development of the TIFSS involved an underestimation of the inlet flow velocity of the sampler that results in a significant overestimation of the theoretical MCE. The ADV data illustrated that the ratio of the inlet flow velocity of the sampler to the ambient velocity was 87% and consequently, it can be assumed that a representative sample of the ambient fine suspended particles entered into the sampler. The field results showed that the particle size distribution of the sediment collected by the TIFSS was statistically similar to that for the ambient sediment in the Red River, Manitoba, Canada. The MCE of the TIFSS in the field trials appeared to be as low as 10%. Collecting a representative sample in the field was consistent with the previous findings that the TIFSS is a suitable sampler for the collection of a representative sample of sufficient mass (e.g., >1 g) for the investigation of the properties of fluvial fine‐grained suspended sediment. Hydrodynamic evaluation of the TIFSS under a wider range of hydraulic conditions is suggested to assess the performance of the sampler during high run‐off events.     

Life history pattern of mosquitofish Gambusia holbrooki (Girard, 1859) in the Tajan River (Southern Caspian Sea to Iran)

Investigation of the ecology of introduced species in new habitats can allow determinations of the degree, direction, and rate of evolutionary change. The introduction of Gambusia holbrooki in the southern Caspian Sea presents such a situation. We evaluated the life history traits of mosquitofish in the Tajan River basin. A total of 744 G. holbrooki specimens were collected between January and December 2008. The maximum observed ages are 0+ years for males and 1+ years for females. Both sexes grew allometrically (negative for males: b=2.442 and positive for females: b=3.232). The overall sex ratio is unbalanced and dominated by females. GSI values suggest that this population of G. holbrooki matures between February–July. The highest mean GSI value is 1.80 for males and 15.97 for females in May. Egg diameter ranges from 1.00 to 3.00 mm with a mean value of 2.098 mm. Absolute fecundity varied from 7 to 57 eggs. Both ova diameter and absolute fecundity were positively correlated to fish size (length and weight). Fecundity relative to total weight fluctuated from 34.44 to 582.64 eggs/g, and to total length from 2.33 to 12.95 eggs/cm. Both were negatively correlated with female size. The characteristics of this population are important with respect to life history of the species.     

Improvement of multiple linear regression method for statistical downscaling of monthly precipitation

This article aims at proposing an improved statistical model for statistical downscaling of monthly precipitation using multiple linear regression (MLR). The proposed model, namely Monthly Statistical DownScaling Model (MSDSM), has been developed based on the general structure of Statistical DownScaling Model (SDSM). In order to improve the performance of the model, some statistical modifications have been incorporated including bias correction using variance correction factor (VCF) to improve the computed variance pattern. We illustrate the effectiveness of the proposed model through its application to 288 rain gauge stations scattered in different climatic zones of Iran. Comparison between the results of SDSM and the proposed MSDSM has indicated superiority of the proposed model in reproducing long-term mean and variance of monthly precipitation. We found that the weakness of MLR method in estimating variance has been considerably improved by applying VCF. We showed that the proposed model provides a promising alternative for statistical downscaling of precipitation at monthly time scale. An investigation of the effects of climate change in different climatic zones of Iran by the use of Representative Concentration Pathways (RCPs) has shown that the most significant change is an increase in precipitation in fall and that the largest share of this increase belongs to arid climate.     

Flood hazard in Wadi Rahbaa area, Egypt

In the last decade, attention has been devoted to the southern part of the Egyptian Red Sea coast due to the large touristic and mining activities. Egypt spares no effort to develop it, to build new urban communities, and to create new job opportunities. Many comprehensive planning studies have been conducted. Many luxurious tourist spots, airports, and harbors have been constructed. These areas are subjected to flash floods, which represent a frequent threat to these urbanization activities that may cause losses in livelihood. By analyzing the geomorphologic features of the study area, intense stream networks are detected that, with the available metrological data, require flood management and analysis to mitigate the possible negative effects and to benefit from the estimation of flood water. Rahbaa basin is a sub-catchment of wadi Hodin. Flash floods within this area threaten the Red Sea coastal plain as well as the main coastal roads. It also directly drained out to the sea, which leads to a loss of huge amounts of flood water that is useful for arid regions. Using geographic information system and remote-sensing tools with the application of a comprehensive graphical modeling (watershed modeling system) supports the hydrological modeling of HEC-1. The total amount of runoff is calculated and the hydrograph of the 50-year return period is computed using rainfall historical data.     

Ecohydrology and flood risk management under climate vulnerability in relation to the sustainable development goals (SDGs): a case study in Nagaa Mobarak Village,Egypt

Natural Hazards - This article aims to provide a thorough assessment of water quality and quantity incorporating the estimation of future patterns as a result of climate change from economic,...     

Mutually interacting tachyon dark energy with variable G and Λ

We consider a tachyonic scalar field as a model of dark energy with interaction between components in the case of variable G and Λ. We assume a flat Universe with a specific form of scale factor and study cosmological parameters numerically and graphically. Statefinder analysis is also performed. For a particular choice of interaction parameters we succeed in obtaining an analytical expression of densities. We find that our model will be stable at the late stage but there is an instability in the early Universe, so we propose this model as a realistic model of our Universe.