Preliminary Study of Catalase Enzyme Activity and Protein Concentrations in the Mediterranean and African Mussels,Mytilus galloprovincialis and Perna perna,Cohabiting on the Same Natural Coastal Site (Figuier,Boumerdes, Algeria)

Ocean Science Journal - Biological monitoring has become one of the most widely used approaches in aquatic monitoring. As a result, the effect of the xenobiotics entrained by the organic and...     

Structural properties of Urfa stone doped with erbium oxide

In this study, we investigated the structural properties of Urfa stone (US) doped with erbium oxide (Er₂O₃). Solid US was powdered by using an agate mortar, and its elemental composition was determined using inductive coupling plasma (ICP) methods. Varying amounts of Er₂O₃ (5, 10, 20, 30, and 40%) were added as a dopant to the US powder using mechanical alloying methods. The resultant samples were sintered at 1000 °C for 1 h. The structural properties of the Er₂O₃-doped US samples were subsequently investigated using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), and photoluminescence methods. Results from the XRD analysis of the Er₂O₃-doped US powder indicated two crystalline phases: (1) calcium oxide (CaO) or lime and (2) Er₂O₃. After the samples were sintered at 1000 °C, CaO, Er₂O₃, calcium carbonate (CaCO₃), and mixed crystalline phases were observed. Results from the FTIR analysis of the Er₂O₃-doped US samples indicated absorption bands at 711.91, 872.08, and 1396.87 cm^?1 in the spectra. Finally, photoluminescence analysis results indicated a shift in the emission and excitation bands to longer and shorter wavelengths, respectively, in the solid state (non-aqueous media) US-Er complex.     

Late Cenozoic stress states around the Bolu Basin along the North Anatolian Fault, NW Turkey

This study defines the Late Cenozoic stress regimes acting around the Bolu Basin along the North Anatolian Fault in northwestern Turkey. The inferred regional stress regime, obtained from the inversion of measured fault-slip vectors as well as focal mechanism solutions, is significant and induces the right-lateral displacement of the North Anatolian Fault. The field observations have also revealed extensional structures in and around the Bolu Basin. These extensional structures can be interpreted as either a local effect of the regional transtensional stress regime or as the result of the interaction of the fault geometries of the dextral Duzce Fault and the southern escarpment of the North Anatolian Fault, bordering the Bolu Basin in the north and in the south, respectively.The inversion of slip vectors measured on fault planes indicates that a strike-slip stress regime with consistent NW- and NE-trending σ_Hmax(σ₁) and σ_Hmin(σ₃) axes is dominant. Stress ratio (R) values provided by inversion of slip vectors measured on both major and minor faults and field observations show significant variations of principal stress magnitudes within the strike-slip stress regime resulting in older transpression to younger transtension. These two stress states, producing dextral displacement along NAF, are coaxial with a consistent NE-trending σ₃ axis. The earthquake focal mechanism inversions confirm that the transtensional stress regime has continued into recent times, having identical horizontal stress axis directions, characterized by NW and NE-trending σ₁ and σ₃ axes, respectively. A locally consistent NE-trending extensional, normal faulting regime is also seen in the Bolu Basin. The stress-tensor change within the strike-slip stress regime can be explained by variations in horizontal stress magnitudes that probably occurred in Quaternary times as a result of the westward extrusion of the Anatolian block.     

Assessment of climate change effects in Aegean river basins: the case of Gediz and Buyuk Menderes Basins

IPCC Fourth Assessment Report (AR4) discloses that the global climate system is undoubtedly warming. Observations have shown that many natural systems, including hydrologic systems and water resources, are being affected by regional climate changes, particularly temperature increases. Eventually, these effects will have to be considered in water resources planning and management. Accordingly, need is indicated to evaluate the impact of expected climate change on hydrology and water resources at regional and local levels. The presented paper summarizes the results of the sub-project studies under the United Nations Development Program-Global Environment Facility (UNDP-GEF) Project. The studies cover the generation of climate change scenarios, modeling of basin hydrology, and testing the sensitivity of runoff to changes in precipitation and temperature. Simulation results of the water budget model have shown that nearly 20% of the surface waters in the studied basins will be reduced by the year of 2030. By the years 2050 and 2100, this percentage will increase up to 35% and more than 50%, respectively. The decreasing surface water potential of the basins will cause serious water stress problems among water users, mainly being agricultural, domestic and industrial water users.     

Study of the Earth's oblateness and rotating atmosphere effects upon an artificial satellite in terms of KS-regular variables

This paper is concerned with an orbit prediction with the KS-regular variables. Perturbations due to the gravitational oblateness of the Earth, and the rotating atmosphere are considered. Application of the method for the perturbed motion are illustrated by numerical and graphical examples for a test case of the orbit.     

Investigation of the photoluminescence properties of Urfa stone powder doped with chromium oxide

In this study, the structural properties of Urfa stone (US) doped with chromium oxide (Cr₂O₃) were investigated using X-ray diffraction (XRD) and FT-IR spectroscopy. The photoluminescence properties of US doped with varying amounts of Cr₂O₃ (5, 10, 20, 30, and 40%) were also investigated. US powder was obtained via grinding with an agate mortar, and Cr₂O₃ was then added as a dopant to the US powder. The samples were sintered at 1000 °C for 1 h. The XRD results of the US powder doped with Cr₂O₃ via mechanical alloying showed the presence of some crystalline phases: calcite (CaCO₃) and eskolate (Cr₂O₃). Furthermore, it was found that calcium oxide (CaO) and tongbaite (Cr₃C₂) were also present in the sintered samples. The photoluminescence analysis results indicated that the emission and excitation bands of the US-Cr complex shifted to longer and shorter wavelengths in the solid state (non-aqueous media), respectively.     

Artificial Neural Network Prediction of Tropospheric Ozone Concentrations in Istanbul,Turkey

Tropospheric (ground‐level) ozone has adverse effects on human health and environment. In this study, next day's maximum 1‐h average ozone concentrations in Istanbul were predicted using multi‐layer perceptron (MLP) type artificial neural networks (ANNs). Nine meteorological parameters and nine air pollutant concentrations were utilized as inputs. The total 578 datasets were divided into three groups: training, cross‐validation, and testing. When all the 18 inputs were used, the best performance was obtained with a network containing one hidden layer with 24 neurons. The transfer function was hyperbolic tangent. The correlation coefficient (R), mean absolute error (MAE), root mean squared error (RMSE), and index of agreement or Willmott's Index (d₂) for the testing data were 0.90, 8.78 µg/m³, 11.15 µg/m³, and 0.95, respectively. Sensitivity analysis has indicated that the persistence information (current day's maximum and average ozone concentrations), NO concentration, average temperature, PM₁₀, maximum temperature, sunshine time, wind direction, and solar radiation were the most important input parameters. The values of R, MAE, RMSE, and d₂ did not change considerably for the MLP model using only these nine inputs. The performances of the MLP models were compared with those of regression models (i.e., multiple linear regression and multiple non‐linear regression). It has been found that there was no significant difference between the ANN and regression modeling techniques for the forecasting of ozone concentrations in Istanbul.     

Statistical analysis of accuracy and precision of GNSS receivers used in network RTK

It is important to make accurate and precise measurements in surveying applications. The concepts of accuracy and precision are not synonymous, even though they are commonly used in place of each other. Nowadays, real-time kinematic (RTK) method is widely used at surveying. As the RTK method can be done depending on a reference station, in countries which establish Continuously Operating Reference Stations (CORS) Network, method known as Network-RTK (N-RTK) can be done depending on the CORS Network. Continuously Operating Reference Stations-Turkey Network (CORS-TR), which consists of 146 reference stations that allow positioning both real time and post-process, was established in 2009. In this study, accuracy and precision of Global Navigation Satellite Systems (GNSS) receivers are tried to determine depending on different correction techniques. For this purpose, 12-h GNSS observations were performed at SLCK-Turkish National Fundamental GPS Network (SLCK-TNFGN) point. The observations were adjusted based on CORS-TR. N-RTK measurements were performed with different GNSS receivers, and accuracies of the receivers were investigated. In order to determine precisions of the receivers, means of RTK measurements were calculated and precisions of the receivers were determined. As a result of investigation, it is seen that accuracy and precision of receivers at 2D positioning and height vary depending on correction technique.