Ion–Cyclotron Resonance Frequency Interval Dependence on the O VI Ion Number Density in the North Polar Coronal Hole 1.5R–3R Region

The frequency intervals in which O VI ions get in resonance with ion–cyclotron waves are calculated using the kinetic model, for the latest six values found in literature on O VI ion number densities in the 1.5R–3R region of the NPCH. It is found that the common resonance interval is 1.5 kHz to 3 kHz. The R-variations of wave numbers necessary for the above calculations are evaluated numerically, solving the cubic dispersion relation with the dielectric response derived from the quasi-linear Vlasov equation for the left-circularly polarized ion-cyclotron waves.     

Factors affecting the biokinetics of technetium (95mTc) in marine macroalgae

Technetium (Tc) biokinetics were investigated in marine macroalgae using ^92mTc as tracer. Green and red algae accumulated Tc (VII) to a very low degree (CF ? 1–20); however, a much higher affinity for pertechnetate was found in some brown algal species (CF > 10³). Comparative tests with different species of brown algae revealed that technetium does not accumulate similarly in all species of this group. Moreover, no significant differences in radionuclide uptake were noted between brown algae exposed to Tc in either the IV or VII oxidation states. Bioaccumulation of technetium appears to be a metabolically controlled process since uptake did not occur in heat-killed individuals and both light and temperature significantly enhanced the accumulation of technetium in brown algae. Dissection of Sargassum vulgare following the uptake phase showed that the rapidly growing air bladder, leaf-like laterals and small branches contained higher Tc concentrations and retained a greater fraction of the radioactivity than the older, cylindrical main axis. Pertechnetate retention in two brown algae was found to be significantly different; their biological half-lives for Tc differed by an order of magnitude ($\text{T}{}_{\mathrm{<mtext>b</mtext><mtext>1</mtext><mtext>2</mtext>}}\text{= 19 and 196}\text{days}$). During depuration, loss took place more rapidly from the younger portions of the seaweed, as evidenced by the highest concentration and greatest fraction of Tc retained in the older, cylindrical main axis. Provided certain precautions are taken, brown algae such as Cystoseira compressa and S. vulgare would serve as good bioindicator organisms for the presence of Tc contamination in marine waters.     

Trace metal levels in fish and crustacea from Northeastern Mediterranean coastal waters

Some fish and crustacea caught near the northeastern Mediterranean coast of Turkey between 1977 and 1980 have been analysed by the AAS technique for their H Hg, Cd, Pb, Zn, Cu, Fe, Ni, Cr and Mn contents. In the crustacea Portunus pelagicus (crab) and Penaeus keratherus (shrimp), the two essential elements Zn and Cu, showed a linear correlation. Among the bony fish, Upeneus moluccensis (gold band goat fish), a member of the Mullidae family, and Portunus pelagicus showed a much greater tendency to accumulate Hg than other species. Although Cr concentrations in the sediments of the area studied were high, Cr levels in the organisms studied were found to be relatively low. The highly toxic metals Hg, Cd and Pb were found to be present in concentrations lower than those reported from other areas of the Mediterranean.     

Regionalization approaches for the periodic parameters of monthly flows: a case study of Ceyhan and Seyhan River basins

Five alternative regionalization approaches in two broad categories, named function‐free and functional approaches, have been proposed to predict periodic behaviours in the basic parameters of monthly stream flows throughout homogeneous regions defined. Function‐free and functional approaches rely on the standardized (or normalized) forms of raw and fitted values of the monthly periodic parameters considered. Homogeneous regions are identified based on these standardized/normalized parameters by means of the hierarchical clustering analysis. The proposed models are tested for two major river basins in south Turkey. It is concluded that the proposed regional models are very effective to estimate periodic behaviour of monthly flows. The functional approaches are quite plausible, and the function‐free approach needs much more parameters. Both types of regionalization approaches can be reliably used to get regional monthly flow estimates for the flow sections where monthly records are not available or too short. Copyright © 2010 John Wiley & Sons, Ltd.     

The links between the categorised Southern Oscillation indicators and climate and hydrologic variables in Turkey

Some previous global and regional studies have indicated teleconnection between the extreme phases of the Southern Oscillation (SO) and Turkish climate and hydrologic variables; however, they failed to suggest a strong correlation structure. In this study, categorised Southern Oscillation index (SOI) and Multivariate ENSO (El Nino Southern Oscillation) index (MEI) series were used to examine the far‐reaching effects of the SO on temperature, precipitation and streamflow patterns in Turkey. These SO indicators were categorised into five subgroups according to their empirical distributions. Correlations between the categorised SO indicators and three analysis variables were computed using the Spearman's rho from lag‐0 to lag‐4. Significance of calculated correlations was tested at the 0·01 level for station‐based analysis and at the 0·05 level for regional analysis. Temperature records demonstrated significant correlations with the categorised SOI and MEI in nearly half of the entire stations. For some categories, precipitation and streamflow were found to be correlated with the SO indicators in some stations mainly in western Turkey. Regional analyses of temperature and precipitation revealed a clear and strong correlation structure with the categorised SO indicators on a large portion of Turkey. This was not concluded by the earlier pertinent studies. Besides, this study showed that significant correlations were obtained not only for the SO extreme phases (namely, El Nino and La Nina) but also for neutral and moderate phases of the SO. Plausible explanations for the observed teleconnection are presented. Copyright © 2009 John Wiley & Sons, Ltd.     

Prediction of seismic energy dissipation in SDOF systems

A simple analytical procedure is developed for calculating the seismic energy dissipated by a linear SDOF system under an earthquake ground excitation. The ground excitation is specified by its pseudo-velocity spectra and effective duration whereas the SDOF system is defined by its natural period of vibration and viscous damping ratio. However, the derived relationship for the energy dissipation demand under an earthquake excitation is sensitive neither to the viscous damping ratio nor the ductility ratio when the SDOF system undergoes inelastic response. Accordingly, the proposed relationship can be employed in an energy-based seismic design procedure for determining the required energy dissipation capacity of a structural system.     

Intensity calibration of DEFPOS data

In this study, details of the intensity calibration of Dual Etalon Fabry-Perot Optical Spectrometer (DEFPOS) were described. At TUBITAK National Observatory (TUG), The DEFPOS was redesigned so as to observe galactic Hα emission line from the diffuse ionized gas with 4′ field of view (FOV) and then was located at the coudé exit of the 150 cm RTT150 telescope (?ahan et al., Research in Astronomy and Astrophysics (RAA) 9(2), 2009). The Absolute intensity calibration of the spectrometer was made by utilizing the data obtained from nine selected regions of NGC 7000 nebula. These regions were selected within 49′ FOV whose intensity calibration was determined to be 850±50 R by Scherb (Astrophys J 243:644–650, 1981). One of these regions was specially selected because of its intensity for the 4′ FOV was estimated as 900 R by Morgenthaler et al. (Astrophys J 563(1):451–461, 2001). For calibration of the DEFPOS data, the intensity values from Ishida and Kawajiri (PASJ 20:95–121, 1968) and the VTSS Hα maps were used and it was found that 1 ADU km s^???1 equals 2337.4 R for a 1200 s exposure time. The radial velocities and the line widths from these regions were also determined and compared with the previous results. These calibrations have been in close agreement.     

Earthquake ground motion characteristics and seismic energy dissipation

The sensitivity of seismic energy dissipation to ground motion and system characteristics is assessed. It is found that peak ground acceleration, peak ground velocity to acceleration (V/A), dominant period of ground excitation and effective response duration are closely correlated with the energy dissipated by a SDOF system. Ductility ratio and damping ratio have no significant influence on the energy dissipation. An energy dissipation index is proposed for measuring the damage potential of earthquake ground motion records which includes the effects of basic excitation and response characteristics contributing to the seismic energy dissipation. The proposed index is compared with several intensity measures for the set of 94 ground motion records considered in the study.