General Model for Infrastructure Multi-channel Wireless LANs

In this paper we develop an integrated model for request mechanism and data transmission in multi-channel wireless local area networks. We calculated the performance parameters for single and multi-channel wireless networks when the channel is noisy. The proposed model is general it can be applied to different wireless networks such as IEEE802.11x, IEEE802.16, CDMA operated networks and Hiperlan\2.Comment: 11 Pages, IJCN

TECHNOLOGICAL TRENDS IN SUPERMARKET REFRIGERATED DISPLAY

Agribusiness,

ECONOMICS OF PRODUCTIVE TRAITS OF SOME EGG-LAYER STRAINS UNDER EGYPTIAN CONDITIONS

University College of North Wales, Bangor, Gwynedd LL57 2UW Wales, Inited KingdomAverage Cost Curve, Profitabilityu, Mortality Rate, Eggs Yield per Hen Housed Per Month, Feed Consumption, Farm Management, Livestock Production/Industries, Production Economics, Productivity Analysis, Research Methods/ Statistical Methods,

The Light Radion Window

Inspired by the Contino-Pomarol-Rattazzi mechanism we explore scenarios with a very light (100 keV to 10 GeV) radion which could be associated with the suppression of the electroweak contribution to vacuum energy. We construct explicit, realistic models that realize this mechanism and explore the phenomenological constraints on this class of models. Compared with axion-like particles in this mass range, the bounds from SN 1987a and from cosmology can be much weaker, depending on the the mass of the radion and its coupling to other particles. With couplings suppressed by a scale lower than 100 TeV much of the mass window from 100 keV to 10 GeV is still open.Comment: 30 pages, 12 figures, published version, software for figure uploade

Leptin induced changes in sperm parameters in Sprague-Dawley rats: role of oxidative stress and its prevention by melatonin / Fayez A. M. Almabhouh

Exogenous leptin administration has been shown to adversely effect sperm count and sperm morphology in normal adult rats. It is however unknown if it affects sperm DNA integrity and increases apoptosis of sperm and testicular tissue cells. This study therefore investigated the effect of leptin administration on sperm count, morphology, sperm DNA integrity, sperm DNA damage, apoptosis and histone-to-protamine ratios and its prevention by melatonin in Sprague-Dawley rats. It also examined the reversal of these effects on sperm parameters for up to 56 days following cessation of leptin treatment. Seventy-eight male Sprague-Dawley rats, aged 12 weeks, were randomized into 13 groups, Group 1 rats acted as a control and were given saline. Group 2 rats were given 60 | μg/kg body weight daily of leptin for 42 days. Group 3 (leptin-melatonin-10) rats were given 60 | μg/kg /day of leptin and 10 mg of melatonin/day/kg body weight in drinking water. Group 4 (leptin-melatonin-20) rats were given 60 |μg/kg/day of leptin and 20 mg of melatonin/day/kg body weight in drinking water. Group 5 (melatonin-10) rats were given 10 mg of melatonin/day/kg body weight in drinking water. The remaining 8 groups were divided into four leptin and four saline treated control groups to examine the reversal of adverse effects of leptin. They were given intra-peritoneal (i.p.) injections of leptin daily at a dose of 60 |ug/kg body weight for 42 days. Control rats received 0.1 ml of 0.9% saline. On day 43, one group of leptin treated rats and one group of age-matched saline treated control rats were euthanized for collection of epididymal sperm. The remaining three groups together with their age-matched saline treated controls were allowed to recover further for either 21, 42 or 56 days. Sperm count, morphology, histone-to-protamine ratios, 8-OHdG, apoptosis, sperm DNA damage, and gene expression profiles using micro-array analysis of the rat testes were determined. Data were analyzed using ANOVA and post-hoc analysis and presented as mean ± SEM. Compared to the controls, sperm count was significantly lower whereas the fraction of sperm with abnormal morphology, histone-to-protamine ratios, the level of 8-OHdG, apoptotic activity and sperm DNA fragmentation were significantly higher in leptin treated rats but not in leptin-melatonin-20 rats. Micro-array analysis revealed significant up-regulation of the expression of respiratory chain enzymes, apoptosis, DNA damage genes and down-regulation of anti-oxidant enzyme genes. All these differences were still evident at days 21 and 42 but not at day 56 of recovery period. In summary, it appears that leptin administration significantly decreases sperm count and down-regulated the anti-oxidant enzyme genes. It increases the fraction of sperm with abnormal morphology, DNA damage, apoptosis, DNA fragmentation and expression of caspase-independent apoptosis genes and DNA damage marker genes. These effects are prevented by concurrent administration of melatonin at dose of 20mg/kg. It appears also these adverse effects of leptin on sperm parameters are completely reversed within 56 days posttreatment in Sprague-Dawley rats

THE EFFECT OF ACTIVITY SCHEDULES TO TEACH APPROPRIATE ACTIVITIES DURING FREE TIME TO STUDENTS WITH AUTISM SPECTRUM DISORDERS

Background: Recent literature suggests that activity schedules increase engagement and independent play skills while decreasing interfering behaviors for students with autism. Therefore, in this study, four students with diagnosed with autism spectrum disorder were taught to use an activity schedules at free time to examine the effects of it on rate of self-stimulatory behavior. Methods: A multiple baseline design was used to examine these effects. The three students were given an activity schedule housed in a binder with five different recess activities. Activities remained constant throughout the study, but the order was changed. Students followed the activity schedule while experimenters tracked frequency of self-stimulatory behaviors. The frequency was then divided by the duration it took the student to complete the schedule to produce rate data. Findings: Results showed that all three students had high levels of self-stimulatory behavior prior to implementation of the schedule (range of subjects: 6.3 – 10.5 times per minute). With the implementation of the activity schedule, all three students had significantly decreased rates of self-stimulatory behavior (range of subjects: (1.5 – 2.2 times per minute). The consistent results show that activity schedules decrease the rate of self-stimulatory behavior at recess. Conclusion: These findings support previous research performed over the last several years and confirmed the effectiveness of activity schedules for students with autism. Article visualizations