Coulomb dissociation of incident 16O at 4.5 GeV/c

Projectile multifragment breakup of ¹⁶O, ²C and ⁷Li at energies 3.0–4.5 A-GeV is studied by means of the Weizsäcker-Williams method. The fragmentation channels of the ¹⁶O projectile at 4.5 A-GeV are investigated and compared with that of ¹⁶O at 200 A-GeV. The events characterized by N _h=0 and the events due to both Coulomb and diffraction dissociation have been selected and analyzed as a function of impact parameter. Also, the dependence of the electromagnetic dissociation cross-section on incident energy and the charge of projectile and target is found.     

Quantitative Structure-Affinity Relationships of Dopamine D2 Receptor Antagonists: A Comparison between Orthopramides and 6-Methoxysalicylamides

A large series of orthopramides (= 2-methoxybenzamides), 6-methoxysalicylamides, and 2,6-dimethoxy-benzamides were examined for their affinity to the dopamine D₂ receptor. The binding data were correlated with physicochemical parameters and ¹³C-NMR chemical shifts using the cross-validated partial least-squares method and multiple linear regression analysis. The results quantitate the influence of electronic factors and lipophilicity to D₂ receptor binding. They also show that the N-[(1-ethylpyrroIidin-2-yl)methyl] and N-(1-benzylpiperidin-4-yl) side-chains affect the mode of binding of these compounds.     

Quality assurance of e-learning in developing countries

In this paper some of the aspects of implementing measures for quality assurance of e-learning in developing countries are discussed. Also the main problems of establishing quality assurance of e-learning are illustrated. The advantages of adopting international measures of quality assurance in those countries together with several recommendations for the future and our conclusion are then given.     

Polyol‐enhanced dispersive liquid–liquid microextraction coupled with gas chromatography and nitrogen phosphorous detection for the determination of organophosphorus pesticides from aqueous samples,fruit juices,and vegetables

Polyol‐enhanced dispersive liquid–liquid microextraction has been proposed for the extraction and preconcentration of some organophosphorus pesticides from different samples. In the present study, a high volume of an aqueous phase containing a polyol (sorbitol) is prepared and then a disperser solvent along with an extraction solvent is rapidly injected into it. Sorbitol showed the best results and it was more effective on the extraction recoveries of the analytes than inorganic salts such as sodium chloride, potassium chloride, and sodium sulfate. Under the optimum extraction conditions, the method showed low limits of detection and quantification within the ranges of 12–56 and 44–162 pg/mL, respectively. Enrichment factors and extraction recoveries were in the ranges of 2799–3033 and 84–92%, respectively. The method precision was evaluated at a concentration of 10 ng/mL of each analyte, and relative standard deviations were found to be less than 5.9% for intraday (n = 6) and less than 7.8% for interday (n = 4). Finally, some aqueous samples were successfully analyzed using the proposed method and four analytes (diazinon, dimethoate, chlorpyrifos, and phosalone) were determined, some of them at ng/mL level.     

Global synchronization of fractional‐order and integer‐order N component reaction diffusion systems: Application to biochemical models

This study considers the problem of control and synchronization between fractional‐order and integer‐order, N‐components reaction‐diffusion systems with nonidentical coefficients and different nonlinear parts. The control scheme is designed using the Lyapunov direct method. The results are exemplified by two significant biochemical models, namely, the fractional‐order Lengyel‐Epstein model and the Gray‐Scott model. To illustrate the effectiveness of the proposed scheme, numerical simulations are performed in one and two space dimensions using Homotopy Analysis Method (HAM).     

Highly efficient widely tunable subpicosecond double mode-locked laser

A high average power (≈150 mW) subpicosecond (0.5 ps) passively double mode-locked dye laser is described. Two synchronized cw pulse trains are generated which are independently tunable over broad wavelength ranges (≈600 Å).     

Singular spectrum analysis and Fisher–Shannon analysis of spring flow time series: An application to Anjar Spring,Lebanon

In this study, the time dynamics of water flow from Anjar Spring was investigated, which is one of the major issuing springs in the central part of Lebanon. Likewise, many water sources in Lebanon, this spring has no continuous records for the discharge, and this would prevent the application of standard time series analysis tools. Furthermore, the highly nonstationary character of the series implies that suited methodologies can be employed to get insight into its dynamical features. Therefore, the Singular Spectrum Analysis (SSA) and Fisher–Shannon (FS) method, which are useful methods to disclose dynamical features in noisy nonstationary time series with gaps, are jointly applied to analyze the Anjar Spring water flow series. The SSA revealed that the series can be considered as the superposition of meteo-climatic periodic components, low-frequency trend and noise-like high-frequency fluctuations. The FS method allowed to extract and to identify among all the SSA reconstructed components the long-term trend of the series. The long-term trend is characterized by higher Fisher Information Measure (FIM) and lower Shannon entropy, and thus, represents the main informative component of the whole series. Generally water discharge time series presents very complex time structure, therefore the joint application of the SSA and the FS method would be very useful in disclosing the main informative part of such kind of data series in the view of existing climatic variability and/or anthropogenic challenges.