Optimization of feeding and growth performance of African catfish (Clarias gariepinus Burchell, 1822) fingerlings.

The present studies were undertaken because feeding remains the single most important determinant of the economic viability of fish culture The research identified the factors pertinent to feeding strategies and growth performance of African catfish Clarias gariepinus (Burchell, 1822) fingerlings. Existing literature relating to the feeding and growth of African catfish is reviewed and the key factors highlighted. A preliminary experiment investigated the effect of the three most important factors - density, light and shelter - on the growth and survival of C. gariepinus. Low density, low light intensity and shelter enhanced growth rates, although not the rates of survival of C. gariepinus fingerlings. The second preliminary experiment was conducted in order to establish an appropriate methodology for measuring feed intake and gastric evacuation. The X-ray method using radio opaque Ballotinis proved successful for accurate estimation of feed intake and gastric evacuation of C. gariepinus. These two studies provided information on environmental parameters in catfish rearing and the appropriate techniques for monitoring feed consumption and evacuation rate. Using feed marker and X-ray technology, based on gastric evacuation and return of appetite, maximum daily feed intake was estimated and a feeding schedule for fingerlings of this species proposed. The effects of particle size and energy level of food on gastric evacuation are evaluated and optimum feed particle sizes and energy levels were determined. Fingerling C. gariepinus grow best on diets of intermediate pellet size (1.5 and 2 mm) and intermediate dietary energy level (22.84 kJ g'1), resulting in high feed intake and feed utilization and low food conversion. Although this species is believed to have a nocturnal feeding habit, to date no research has established a diel rhythm. Using infrared video technology and continuous recording of feeding activities a precise diel rhythm was identified. Predominantly a nocturnal feeder, C. gariepinus shows two distinct feeding peaks given access to feed for 24 h - one immediately after the onset of dark phase and the second just prior to the onset of the light phase. In order to maximize growth performance and feed intake, fish were fed with diets of intermediate pellet size and energy level in three different modes - following their feeding rhythm, only in light phase and in light and dark phase continuously. Fish fed in response to their rhythmic feeding peak had highest weight gain, feed intake and feed utilization and lowest feed conversion. On this basis, a comprehensive feeding guide for fmgerling C. gariepinus was established

Development of indole sulfonamides as cannabinoid receptor negative allosteric modulators

This Letter was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) and the Scottish Universities Life Sciences Alliance (SULSA) in 2011Peer reviewedPostprin

Effect of certain commercial compounds in controlling root-knot nematodes infected potato plants

To examine the effect of certain commercial compounds against root-knot nematode (Meloidogyne incognita) which infect potato plants (Solanum tuberosum L. var. sponta). Two experiments were carried out under laboratory and field conditions during 2012 and 2013 seasons. Eight nematicides were used as treatments i.e., Mocap, Super control, Dento, Nematex, Vertimyl, Oxamyle, Bionematone, and Bioxy+. The successful treatments were chosen due to their effectiveness on percentage reduction in nematode populations, maximize plant production. The chosen treatments applied in soil naturally infected with nematode in the experimental field in Nubaria, Behira Governorate, North Egypt. Results exhibited significantly reduction in all nematode developmental stages in plant and soil, ex. number of egg masses, galls and nematodes in 250 cm3 soil with all chemical compounds. The consequence of vegetative growth parameters and yield were increased significantly with tested treatments compared with control. Moreover, results of laboratory experiments recorded that 87 to 98% inhibition for egg-masses hatching and 85 to 98% mortality for juveniles, respectively, with 90% for the lethal concentration of Bioxy+, Oxamyl and Vertimyl

Assessment of Fences as Noise Barriers: A Case Study in New Cairo, Egypt

Noise levels in Egypt exceed acceptable thresholds due to high population and lack of mandatory sound regulations. According to noise measurements done by “The National Network for Noise Level Measurement in Greater Cairo” most of the areas examined ( main squares, industrial areas, main roads, residential areas, commercial and administrative areas in Cairo governorate)  had shown that noise levels exceeded the standard permissible levels that are identified by the Environmental Law 4/1994 and its executive regulations. Noise levels reached up to 75-85 decibels (dB), which is considered unacceptable as noise levels should not exceed 65 dB during daytime and 55 dB during night due to law number 4/1994. On the other hand, fences are considered a common feature within the Egyptian urban context and are mainly constructed for safety and privacy reasons. This research assesses the effectiveness of existing fences as noise barriers and specifies factors that reduce noise levels. Site measurements and photographs were taken for the fence of a residential compound in new Cairo, where noises arising from surrounding places cause annoyance. MEP services were the main sources of disturbing continuous noise along with social activities and traffic noises. Measurements were performed using TM-102 digital sound level meter. Readings were recorded at various time intervals in front and behind of the fence and noise reduction levels were calculated. Measurements revealed that the fence acts as a good noise barrier and that combined configuration of the fence resulted in the attenuation of noise to acceptable levels

Missing at random assumption made more plausible: evidence from the 1958 British birth cohort

Objective: Non-response is unavoidable in longitudinal surveys. The consequences are lower statistical power and the potential for bias. We implemented a systematic data-driven approach to identify predictors of non-response in the National Child Development Study (NCDS; 1958 British birth cohort). Such variables can help make the missing at random assumption more plausible, which has implications for the handling of missing data. / Study Design and Setting: We identified predictors of non-response using data from the 11 sweeps (birth to age 55) of the NCDS (n = 17,415), employing parametric regressions and the LASSO for variable selection. / Results: Disadvantaged socio-economic background in childhood, worse mental health and lower cognitive ability in early life, and lack of civic and social participation in adulthood were consistently associated with non-response. Using this information, along with other data from NCDS, we were able to replicate the “population distribution” of educational attainment and marital status (derived from external data), and the original distributions of key early life characteristics. / Conclusion: The identified predictors of non-response have the potential to improve the plausibility of the missing at random assumption. They can be straightforwardly used as “auxiliary variables” in analyses with principled methods to reduce bias due to missing data

OPTIMUM WINDBREAKER TO REDUCE WIND TUNNEL EFFECT ON OCCUPANT COMFORT AT PEDESTRIAN LEVEL (A CASE STUDY OF BAU BUILDING IN TRIPOLI)

Shape, size, building orientation and its interaction with the surrounding buildings can cause wind tunnel that affect the pedestrian comfort. This paper aims to select the optimum windbreaker height and thickness for reducing the effect of wind tunnels on pedestrian comfort, by selecting the building of Beirut Arab University (BAU)-Tripoli campus as a case study. Different alternative designs have been simulated and compared with the comfort criteria of pedestrians to conclude the optimum solution that can be adapted on the selected building and on any other cases that have similar characteristics

Improvement of Synchronous Machine Dynamic Characteristics via Neural Network Based Controllers

This paper presents Simulation and experimental study aimed at investigating the effectiveness of an adaptive artificial neural network stabilizer on enhancing the damping torque of a synchronous generator. For this purpose, a power system comprising a synchronous generator feeding a large power system through a short tie line is considered. The proposed adaptive neuro-control system consists of two multi-layered feed forward neural networks, which work as a plant model identifier and a controller. It generates supplementary control signals to be utilized by conventional controllers. The details of the interfacing circuits, sensors and transducers, which have been designed and built for use in tests, are presented. The synchronous generator is tested to investigate the effect of tuning a Power System Stabilizer (PSS) on its dynamic stability. The obtained simulation and experimental results verify the basic theoretical concepts