Journal of the Association of Arab Universities for Basic and Applied Sciences最新文献

This article analyzes the effects of Hall and ion-slip parameters on mixed convective electrically conducting nanofluid flow between two parallel concentric cylinders considering magnetic field. The governing equations are non dimensionalized. The resulting system of nonlinear ordinary differential equations is solved utilizing homotopy analysis method. The influence of the magnetic parameter, Hall, ion-slip, Brownian motion and thermophoresis parameters on non-dimensional velocity, temperature and nanoparticle volume fraction is analyzed and represented graphically. It is found that increasing Hall and ion-slip parameters decrease the temperature but increase the velocity and nanoparticle volume fraction and the opposite trend observed when magnetic parameter increased. It is observed that as Brownian motion and thermophoresis parameters increase, the velocity and temperature increase but the nanoparticle volume fraction decreases.

This work is concerned with the discussion of the numerical approximation for random Cauchy transport model in one dimension. The random (forward time, backward space) finite difference scheme is used to find the stochastic solution. The impression of the consistency and the random von-Neumann stability technique under the mean square sense are studied. Using some examples, we can support our main objective of this model statistically.

Antioxidant is a molecule that inhibits the oxidation of other molecules caused by free radicals. Antioxidant activity of a dairy food is important both for the shelf life of the product as well as for protection from oxidative damage in the human body. The objective of this work was to demonstrate the effects of natural antioxidants (plant-based sources) against synthetic antioxidants in dairy food.

This paper is devoted to the study of a new graph, called $m^k$-graph and denoted by $m^k\left(G\right)$, that arises from a simple graph G by k successive iterations of a special kind of construction. We provide some of its topological indices such as Wiener index, Hyper-Wiener index, Wiener polarity, Zagreb indices, Schultz and modified Schultz indices and Wiener-type invariant. Some Formulas concerning classical graphs are settled to show the scope of this study.

The number of diabetes mellitus (DM) patients is one of the major concerns worldwide. As one of the main mechanisms of DM pathology is the involvement of oxidative stress, here we investigate the antioxidant capacities of frankincense (FRN) to treat or reduce the DM complications in the brain cortices of DM rats. Animals were segregated into four groups, the control group, FRN group given a dose of 500 mg of FRN/kg for 5 weeks, DM group given a single dose of 150/kg i.p of alloxan to induce diabetes and DM + FRN group given a single dose of 150/kg i.p to induce DM then followed by FRN 500 mg/kg for 5 weeks. The animals were sacrificed; their cerebral cortices were removed and used for biochemical and histopathological analyses.

Alloxan treatment in the DM group showed significant reductions in catalase (CAT) activity and other non-enzymatic antioxidants i.e. thiol groups, concomitant with decreases in the levels of protein and albumin and increasing the level of uric acid. However, FRN administration to DM animals in DM + FRN group showed significant recovery of antioxidants, the thiol contents (total thiols, protein thiols and glutathione) of DM + FRN group have been increased as compared with DM animals (p < 0.05). A recovery of CAT activity (p < 0.05) to almost the levels of control rats with the recovery in protein and albumin levels (p < 0.05) have been observed when FRN was administered. The uric acid level increased in DM group, came back to the levels of control after administration of FRN (p < 0.05). We also observed that FRN reduces the histopathological damage caused by alloxan in DM + FRN group. It is concluded that FRN shows a beneficial effects that can reduce the oxidative damage caused by alloxan induced DM in the cortex of rats.

Monitoring marine biodiversity is costly and practical solutions have to be implemented to identify species and their preferred habitats, particularly in this era of rapid global change. Citizen science has proven to be effective and with high potential for monitoring efforts, and has been extensively applied to biodiversity. We have used the citizen science approach to engage the general public and stakeholders to contribute improving the current knowledge of sea snake biodiversity in Qatar and the Gulf Region. Logistic regression analysis using demographic data from interview surveys conducted in Qatar has indicated that the people having seen more sea snakes are older than 30 years and are Qatari citizens and/or fishermen from India.

Of the ten species of sea snakes listed in the literature to be present in the Gulf Region, most of them have been reported for Qatar, Bahrain, United Arab Emirates and Saudi Arabia. However, the number of species present is often assumed based on their occurrence within the Arabian Gulf rather than on actual captures and appropriate identification. The creation of marine reference biological scientific collections to properly identify the species and make accurate biodiversity inventories is an urgent priority for the countries in the Gulf region. To this end, contributions by stakeholders and the general public for this study have proven to be very useful. However a larger networking with local and international scientists and stakeholders is still needed to adequately survey the country’s current biodiversity, identify research priorities and eventually provide the scientific input needed to assist biodiversity management related to renewable resource management and marine conservation in the Arabian Gulf Region.

The concentration and spatial distribution of the gamma ray emitting ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs radionuclides in dumpsite soils in Agbara were analyzed with the aim of evaluating the radiation hazards and excessive lifetime cancer risk using well calibrated HPGe γ-ray spectrometry technique. The ranges of activity concentrations of ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs are 11.5 ± 1.0 ↔ 166 ± 40 Bq kg⁻¹, 15.6 ± 1.8 ↔ 31.4 ± 2.3 Bq kg⁻¹, 20.4 ± 1.3 ↔ 366 ± 30 Bq kg⁻¹ and 0.52 ± 0.1 ↔ 8.44 ± 0.2 Bq kg⁻¹ respectively. Radiological parameters such as absorbed dose rate, radium equivalent, annual effective dose equivalent, internal and external hazard indices, gamma level index, activity utilization index, annual genetic significant dose equivalent, exposure rate and excessive lifetime cancer risk were calculated to know the complete radiological hazardous nature of the dumpsite soils to the inhabitants of the sites. The calculated radiological parameters were higher than the world average value in two of the sampling points. The ratio of the detected radioisotopes was calculated for spatial distribution of natural radionuclides in the study area. RESRAD computer code was applied to calculate the total effective dose equivalent (TEDE). The code was also used to calculate the probability of excess lifetime cancer incurred by dwellers/inhabitants of the dumpsites, the level of which was determined to be 0.5 × 10⁻⁴ and 2.5 × 10⁻⁵ for Idowale and Ibijola dumpsite soils over a period of 30 years respectively. Therefore, the radiological risks to the general populations from waste enhanced naturally occurring radioactive materials (WENORM) from the Idowale dumpsite top soils are considered to be significant.

Using the Exp-function method, we derive exact solutions of the nonlinear space–time fractional Telegraph equation and space–time fractional KPP equation. As a result, we obtain many exact analytical solutions including hyperbolic function. The fractional derivative is described in Jumarie’s modified Riemann–Liouville sense. This method is very effective and convenient for solving nonlinear fractional differential equations.

In this paper, we shall establish sufficient conditions for the uniform asymptotic stability and boundedness of solutions of a certain third order vector nonlinear non-autonomous differential equation with multiple deviating arguments, by using a Lyapunov function as basic tool. In doing so we extend some existing results. Example is given to illustrate our results.