Culture performance of Oreochromis niloticus and Sarotherodon galilaeus using similar management strategies

Sarotherodon galilaeus and Oreochromis niloticus are 2 readily available fish species in Nigeria, often cultured interchangeably. The findings are presented of a comparative study conducted to provide information on their performance using similar nutrient loadings without supplemental feed. Results showed a better performance of O.niloticus over S.galilaeus, which may be partly explained by the dietary mechanisms of the fish. Further trials on gut content analyses are require

Mood, Attention, and the Aha! Moment

Although research has generally shown that positive affect broadens attentional scope and enhances creativity, recent evidence suggests that the mood-attention relationship depends on the present dominant attentional focus. The current research seeks to extend these findings to the ability to solve insight problems. Undergraduates were primed to focus globally or locally and induced with a mood before completing insight problems. Contrary to past research, participants primed with a local, as opposed to global, focus of attention solved significantly more insight problems. There was no significant mood-attention interaction on insight problem-solving ability. This suggests that convergent thinking may play as substantial a role as divergent thinking in insight problem solving. Moreover, at least in the realm of insight, mood does not act as a signal that determines if a dominant attentional focus is acted upon or not

A review of solar collectors and thermal energy storage in solar thermal applications

Thermal applications are drawing increasing attention in the solar energy research field, due to their high performance in energy storage density and energy conversion efficiency. In these applications, solar collectors and thermal energy storage systems are the two core components. This paper focuses on the latest developments and advances in solar thermal applications, providing a review of solar collectors and thermal energy storage systems. Various types of solar collectors are reviewed and discussed, including both non-concentrating collectors (low temperature applications) and concentrating collectors (high temperature applications). These are studied in terms of optical optimisation, heat loss reduction, heat recuperation enhancement and different sun-tracking mechanisms. Various types of thermal energy storage systems are also reviewed and discussed, including sensible heat storage, latent heat storage, chemical storage and cascaded storage. They are studied in terms of design criteria, material selection and different heat transfer enhancement technologies. Last but not least, existing and future solar power stations are overviewed.Peer reviewe

Japan's Public Pension System in the Twenty-First Century.

In this paper, the author first briefly discuss the structure of Japan's public pension system, the history of that system, the raison d'etre of a public pension sustem, some of the defects in the current system, the origins of those defects, possible ways of alleviating those defects, future prospects for Japan's public pension system in the face of rapid population aging, and proposals for reforming Japan's public pension system.PUBLIC PENSION ; SOCIAL SECURITY ; JAPAN

Numerical investigations of heat transfer in phase change materials using non-equilibrium model

Phase change materials (PCMs) are drawing increasing attention of researchers nowadays, and they play a pivotal role in thermal energy storage (TES) used in renewable energy resources applications, since these renewable energy, such as solar energy, wind energy and tidal energy, are intermittent and not available at any time. However, most of PCMs suffer from low thermal conductivities prolonging the charging and discharging processes. Metal foams with relatively high thermal conductivities, are believed to be able to enhance heat transfer performance of PCMs for those applications. In this paper, a two-equation non-thermal equilibrium model has been employed to tackle the phase change heat transfer problem in PCMs composites embedded into metal foams. Numerical results show good agreement with experimental data, and indicate that a better heat transfer performance can be achieved by using the metal foams of smaller pore size and smaller porosity, and heat transfer performance of PCMs can be enhanced by up to 10 times by embedded metal foams into PCMs.Peer reviewe

Ecophysiological perspectives of blue-green algal blooms

Blue-green algae (cyanobacteria) have had a profound and unparalled impact on the aquatic environment because of the phenomenon of bloom formation. In many countries, water management is threatened with extensive and persistent noxious blooms of blue-green algae in surface and near-surface mesotrophic and eutrophic waters. In view of this, ecological and physiological factors responsible for blue-green algal dominance are discussed. The implications of cyanobacterial blooms are highlighted and recommendations made to combat this menac

Bucket shaking stops bunch dancing in Tevatron

Bunches in Tevatron are known to be longitudinally unstable: their collective oscillations, also called "dancing bunches," persist without any signs of decay. Typically, a damper is used to stop these oscillations, but recently, it was theoretically predicted that the oscillations can be stabilized by means of small bucket shaking. Dedicated measurements in Tevatron have shown that this method does stop the dancing.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1 Apr 2011. New York, US

The Role of Supply Chains and International Networks in Enhancing the Agricultural Sector’s Competitiveness in Cambodia, Laos, Myanmar and Vietnam (CLMV)

The expansion of supermarkets in Asia typifies the effects of the increasing liberalization in trade and the inflow of foreign investment. The supermarket revolution thus occupies a focal point in this paper which tracks its phenomenal growth in Asia, and its continuing inroads into CLMV – Cambodia, Laos, Myanmar and Vietnam. Given the significant transformation that this major development is expected to bring into these countries’ agricultural sector as well as food distribution systems, the paper examines the growing role of supply chain management. The value-adding potential at each level of the chain will allow agriculture to drive overall development by leveraging on the nations’ advantage at the input, processing, wholesale and retail trade as well as international trade levels. The initial successes in Myanmar and Vietnam are highlighted. In the wake of these developments, the paper emphasizes the glaring need to address the issue of how to balance the interests of the key players along the supply chain with that of the national interest, and how to gear up for globalization while also strengthening internal structures and institutions. The challenge is to ensure the orderly and balanced development of supply chains. Specifically, the respective governments would need to launch focused and holistic interventions that would not only manage the supply chains and international networks, but also minimize the marginalization of small farmers and other stakeholders.supply chains, international networks, trade liberalization

Exergy optimisation for cascaded thermal storage

Cascaded thermal storage, consisting of multiple Phase Change Materials (PCMs) with different melting temperatures, has been proposed to solve the problem of poor heat transfer caused by unavoidable decrease of temperature differences during heat exchange process. This paper conducts a theoretical study of the overall thermal performance for a cascaded thermal storage system. Both heat transfer rate and exergy efficiency are taken into account. The main findings are: the cascaded arrangement of PCMs enhances the heat transfer rate by up to 30%, whilst it does not always improve the exergy efficiency (-15 to +30%). Enhanced heat transfer and reduced exergy efficiency can both be attributed to the larger temperature differences caused by the cascaded arrangement. A new parameter hex (exergy transfer rate) has been proposed to measure the overall thermal performance. It is defined as the product of heat transfer rate and exergy efficiency, representing the transfer rate of the utilisable thermal energy. The simulation results indicate that the cascaded thermal storage has higher overall thermal performance than the single-staged storage despite of higher exergy efficiency loss.Peer reviewe

An appraisal of the current status of the fisheries of Eleiyele Reservoir by its fisheries cooperatives

In a study undertaken to evaluate the status of the fisheries of Eleiyele Reservoir (Nigeria) between 1995 and 1997, thermal stratification was observed to breakdown between December and March. Of the physico-chemical variables, transparency was positively correlated (p<0.05) with primary productivity, conductivity and dissolved oxygen concentration. Primary productivity ranged between 0.38mgC/m super(2)/d and 3.OmgC/ m super(2)/d, being lowest in April. BOD values ranged between 1.3mg-2.2mgO/l indicative of clean unpolluted water. Nine fish species belonging to the families Cichlidae, Centropomidae and Mochokidae were identified. Cichlids were the most abundant with Hemichromis species being predominant. Fishing was only carried out in the reservoir during the dry season months of November to April. Fish landing data for the reservoir, obtained from the Fisheries Division of the Ministry of Agriculture and Natural resources, Oyo State, in conjunction with comparative data from the Cooperative fishermen was low. It demonstrated a decreasing trend from January to April and during the period between 1985 and 1996, when compared with data collected in 1985 and 1986 from a previous similar study. Reasons for the low fish yield from the reservoir are discussed and compared with other Nigerian reservoir