A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban （236）, rural （80） a...A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban （236）, rural （80） and industrial areas （97） were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer （GFAAS）. Cognitive development was measured by the ＇McCarthy Scales of Children＇s Abilities Test＇ （MSCA）. Significant differences found in the mean cognitive scores between the urban （94.40）, industrial （102.90） and suburban children （101.24） （p 〈 0.001）, with the blood lead between the urban （3.66 p.g/dL）, industrial （3.54 μg/dL） and suburban children （3.04μg/dL） （p = 0.022）. Significant inverse correlations between blood lead and cognitive scores found for all groups （p 〈 0.001）, urban （p 〈 0.001） and suburban children （p 〈 0.001）. Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders （p _〈 0.001）. The urban children＇s cognitive scores were significantly influenced by blood lead levels and household income （p 〈 0.001）. However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers＇ education, number of siblings, sequence in the family and the household income （p 〈 0.001 ）. Blood lead below 10μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development.展开更多
The solar energy conversion system is very interesting alternative on supplement the electric system generation, due to the persistent cost reduction of the overall system and cleaner power generation. To obtain a sta...The solar energy conversion system is very interesting alternative on supplement the electric system generation, due to the persistent cost reduction of the overall system and cleaner power generation. To obtain a stable voltage from an input supply （PV cells） that is higher and lower than the output, a high efficiency and minimum ripple DC-DC converter required in the system for residential power production. Buck-boost converters make it possible to efficiently convert a DC voltage to either a lower or higher voltages. Buck-boost converters are especially useful for PV maximum power tracking purposes, where the objective is to draw maximum possible power from solar panels at all times, regardless of the load. This paper analyzes and describes step by step the process of designing, and simulation of high efficiency low ripple voltage buck-boost DC-DC converter for the photovoltaic solar conversion system applicable to a （typical） single family home based on battery-based systems. The input voltage can typically change from （20 V） initially, down to （5 V）, and provide a regulated voltage within the range of the battery （12 V）. PLECS simulation results provide strong evidences about the high efficiency, minimum ripple voltage, high accuracy, and the usefulness of the system of the proposed converter when applied to either residential or solar home applications.展开更多
This paper examines the livelihood challenges experienced in Rwanjaba Lakeshore Community during the period of low water level in Lake Victoria between 2004 and 2007 and identifies the livelihood coping strategies tha...This paper examines the livelihood challenges experienced in Rwanjaba Lakeshore Community during the period of low water level in Lake Victoria between 2004 and 2007 and identifies the livelihood coping strategies that were adopted to address them.A total of 55 households were randomly sampled and the data collection methods included household questionnaires and participant observations.The data were analyzed using the Statistical Package for Social Science(SPSS) and the results presented with the help of descriptive statistics.The livelihood challenges experienced during the low lake water level included fish shortage(34.5%),household food scarcity(23.6%),sex for fish(18.2%),family breakdown(12.7%),increased theft(7.2%) and accidents due to the exposed rocks in the lake(3.6%).The livelihood coping strategies adopted to redress the challenges included causal labour(32.7%),maize roasting(23.6%),sand mining(18.2%),selling of snacks(12.7%),selling household property(9.1%) and resorting shop and market credits(3.6%).The paper proposes a number of recommendations for improving the livelihood of the community ranging from policy reforms to the diversification of activities.展开更多
A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the ...A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.展开更多
Under the framework of uniformly smooth Banach spaces, Chang proved in 2006 that the sequence {xn} generated by the iteration xn＋1 =αn＋1f（xn） ＋ （1 - αn＋1）Tn＋1xn converges strongly to a common fixed point of...Under the framework of uniformly smooth Banach spaces, Chang proved in 2006 that the sequence {xn} generated by the iteration xn＋1 =αn＋1f（xn） ＋ （1 - αn＋1）Tn＋1xn converges strongly to a common fixed point of a finite family of nonexpansive maps {Tn}, where f ： C → C is a contraction. However, in this paper, the author considers the iteration in more general case that {Tn} is an infinite family of nonexpansive maps, and proves that Chang＇s result holds still in the setting of reflexive Banach spaces with the weakly sequentially continuous duality mapping.展开更多
To determine the stable homotopy groups of spheres π＊（S） is one of the central problems in homotopy theory. Let p be a prime greater than 5. The authors make use of the May spectral sequence and the Adams spectral...To determine the stable homotopy groups of spheres π＊（S） is one of the central problems in homotopy theory. Let p be a prime greater than 5. The authors make use of the May spectral sequence and the Adams spectral sequence to prove the existence of a Bn-related family of homotopy elements, β1ωnγs, in the stable homotopy groups of spheres, where Bn〉 3, 3≤s〈 p-2 and the Bn-element was detected by X. Liu.展开更多
文摘A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban （236）, rural （80） and industrial areas （97） were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer （GFAAS）. Cognitive development was measured by the ＇McCarthy Scales of Children＇s Abilities Test＇ （MSCA）. Significant differences found in the mean cognitive scores between the urban （94.40）, industrial （102.90） and suburban children （101.24） （p 〈 0.001）, with the blood lead between the urban （3.66 p.g/dL）, industrial （3.54 μg/dL） and suburban children （3.04μg/dL） （p = 0.022）. Significant inverse correlations between blood lead and cognitive scores found for all groups （p 〈 0.001）, urban （p 〈 0.001） and suburban children （p 〈 0.001）. Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders （p _〈 0.001）. The urban children＇s cognitive scores were significantly influenced by blood lead levels and household income （p 〈 0.001）. However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers＇ education, number of siblings, sequence in the family and the household income （p 〈 0.001 ）. Blood lead below 10μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development.
文摘The solar energy conversion system is very interesting alternative on supplement the electric system generation, due to the persistent cost reduction of the overall system and cleaner power generation. To obtain a stable voltage from an input supply （PV cells） that is higher and lower than the output, a high efficiency and minimum ripple DC-DC converter required in the system for residential power production. Buck-boost converters make it possible to efficiently convert a DC voltage to either a lower or higher voltages. Buck-boost converters are especially useful for PV maximum power tracking purposes, where the objective is to draw maximum possible power from solar panels at all times, regardless of the load. This paper analyzes and describes step by step the process of designing, and simulation of high efficiency low ripple voltage buck-boost DC-DC converter for the photovoltaic solar conversion system applicable to a （typical） single family home based on battery-based systems. The input voltage can typically change from （20 V） initially, down to （5 V）, and provide a regulated voltage within the range of the battery （12 V）. PLECS simulation results provide strong evidences about the high efficiency, minimum ripple voltage, high accuracy, and the usefulness of the system of the proposed converter when applied to either residential or solar home applications.
文摘This paper examines the livelihood challenges experienced in Rwanjaba Lakeshore Community during the period of low water level in Lake Victoria between 2004 and 2007 and identifies the livelihood coping strategies that were adopted to address them.A total of 55 households were randomly sampled and the data collection methods included household questionnaires and participant observations.The data were analyzed using the Statistical Package for Social Science(SPSS) and the results presented with the help of descriptive statistics.The livelihood challenges experienced during the low lake water level included fish shortage(34.5%),household food scarcity(23.6%),sex for fish(18.2%),family breakdown(12.7%),increased theft(7.2%) and accidents due to the exposed rocks in the lake(3.6%).The livelihood coping strategies adopted to redress the challenges included causal labour(32.7%),maize roasting(23.6%),sand mining(18.2%),selling of snacks(12.7%),selling household property(9.1%) and resorting shop and market credits(3.6%).The paper proposes a number of recommendations for improving the livelihood of the community ranging from policy reforms to the diversification of activities.
文摘A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.
基金the Youth Founction of Sichuan Educational committee (No.08ZB002)the Foundation of Yibin College (No.2006Q01)
文摘Under the framework of uniformly smooth Banach spaces, Chang proved in 2006 that the sequence {xn} generated by the iteration xn＋1 =αn＋1f（xn） ＋ （1 - αn＋1）Tn＋1xn converges strongly to a common fixed point of a finite family of nonexpansive maps {Tn}, where f ： C → C is a contraction. However, in this paper, the author considers the iteration in more general case that {Tn} is an infinite family of nonexpansive maps, and proves that Chang＇s result holds still in the setting of reflexive Banach spaces with the weakly sequentially continuous duality mapping.
基金supported by the National Natural Science Foundation of China(No.11571186)
文摘To determine the stable homotopy groups of spheres π＊（S） is one of the central problems in homotopy theory. Let p be a prime greater than 5. The authors make use of the May spectral sequence and the Adams spectral sequence to prove the existence of a Bn-related family of homotopy elements, β1ωnγs, in the stable homotopy groups of spheres, where Bn〉 3, 3≤s〈 p-2 and the Bn-element was detected by X. Liu.
