A Genetic Algorithm-based Framework for Soft Handoff Optimization in Wireless Networks

In this paper, a genetic algorithm (GA)-based approach is used to evaluate the probability of successful handoff in heterogeneous wireless networks (HWNs) so as to increase capacity and network performance. The traditional handoff schemes are prone to ping pong and corner effects and developing an optimized handoff scheme for seamless, faster, and less power consuming handoff decision is challenging. The GA scheme can effectively optimize soft handoff decision by selecting the best fit network for the mobile terminal (MT) considering quality of service (QoS) requirements, network parameters and user’s preference in terms of cost of different attachment points for the MT. The robustness and ability to determine global optima for any function using crossover and mutation operations makes GA a promising solution. The developed optimization framework was simulated in Matrix Laboratory (MATLAB) software using MATLAB’s optima tool and results show that an optimal MT attachment point is the one with the highest handoff success probability value which determines direction for successful handoff in HWN environment. The system maintained a 90%  with 4 channels and more while a 75% was obtained even at high traffic intensity

Evaluation of Toxicological Effects of Spondias Mombin in Adult Male Wistar Rats

Spondias mombin is relied on for various herbal remedies for numerous conditions. This study is to evaluate the acute toxic effect of mombin in adult male Wistar rats. Acute toxicity test was carried out with modified Lorke’s method. Twenty-five male rats weighing between 120-180g were used for the sub-chronic study. The rats were divided into five groups A- E (n=5). Group A served as control. Group B and C received respectively 250mgkg-1 and 500mgkg-1 body weight doses of aqueous leaf extract,  groups D and E received  250mgkg-1 and 500mgkg-1 body weight doses of ethanolic extract. Treatments lasted for twenty eight days. Acute toxicity test carried out showed that leaf extracts of Spondias mombin did not produce mortality in rats.  Significant (p<0.05) reduction in brain and kidney weights was observed in group E treated with 500mgkg-1 of ethanolic extract. Similarly, significant (p<0.05) reduction was observed in spleen weights in groups C and E that were treated with 500mgkg-1 of both extracts. The levels of LDL (p<0.001) and ALP (p<0.05) were significantly reduced.  Alterations in the histology of the liver and kidney of extracts treated groups were observed. Conclusion: This result suggests that although the use of the leaf extracts of Spondias mombin is relatively safe, hepatic and renal toxicity may occur with prolonged use. Keywords: Adverse effects, Mortality, Methods, Complication, Utilizatio

Safety of Ionizing Radiation in Selected Conventional X-ray Diagnostic Centres in Calabar and Uyo metropolises, Nigeria

Background: Humans are inevitably exposed to background radiation in work and public environments. The aim of this work is to assess the effectiveness of the secondary barriers in conventional x-ray diagnostic centers in Calabar and Uyo metropolises. This is by determining the weekly and annual effective dose in their respective uncontrolled areas and comparing them with the international recommendations. Materials and Methods: This cross-sectional study was conducted in three x-ray diagnostic centers in Calabar, represented as C1, C2, and C3 respectively, and in four xray diagnostic centers in Uyo, represented as U1, U2, U3, and U4 respectively. Background radiation was measured using Radex 1212 A-A battery-powered survey meter, at a distance of 2.5meters away from the xray units. Radiation measurement was taken at three different spots, and the recorded data were analyzed. Results: The mean calculated effective dose per week in mSv/week for each diagnostic center was given as 0.130 ± 0.0068mSv/week. Also, the mean calculated effective dose per year in mSv/year for each center was given as 0.66 ± 0.35mSv/year. These values are below the National Commission on Radiation Protection (NCRP) recommendations of 0.02mSv/week and 1mSv/year respectively. From the results, the mean calculated chance of developing cancer was 2.33 ×10-3% which was lower than the NCRP recommendation for continuous public exposure of 5.5×10-3 %. Conclusion: It could be concluded that the integrity of the shielding designs and their dimensions assessed are safe

WTO must ban harmful fisheries subsidies

Sustainably managed wild fisheries support food and nutritional security, livelihoods, and cultures (1). Harmful fisheries subsidies—government payments that incentivize overcapacity and lead to overfishing—undermine these benefits yet are increasing globally (2). World Trade Organization (WTO) members have a unique opportunity at their ministerial meeting in November to reach an agreement that eliminates harmful subsidies (3). We—a group of scientists spanning 46 countries and 6 continents—urge the WTO to make this commitment..