2,217 research outputs found

    Survey of Major Points of Interest About Reactions of Cholinesterases

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    Three areas of current interest and activity in the study of the cholinesterases have been chosen for comment: Aging of phosphorylated cholinesterases. Recent work indicates that aging (loss of groups attached to the phosphorus) can be brought about by at least two mechanisms. It now seems probable that aging is a more general reaction and is not restricted to the cholinesterases. Inhibition by excess substrate and other effects. An attempt has been made to bring together into one model experimental results from a number of different approaches. These include acceleration of hydrolysis and inhibition by quaternary ammonium compounds, differences in pH-rate profiles for various substrates and various inhibitors, substrate inhibition and inhibition by haloxon. Molecular weight of acetylcholinesterase in membranes. A recent paper indicating that acetylcholinesterase in membranes is monomeric is discussed

    Charter Schools as a Choice for Missouri Families

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    Charter schools are publically funded, non-sectarian, tuition-free organizations that educate students. The charter model was created to allow schools to remain free from some governmental regulations and to offer parents a tuition-free choice for K-12 education. Across the country, millions of students attend charter schools, and another million remain on waiting lists to get into these schools. Ultimately, charter schools attract families that have similar belief systems and missions as the school claims, and again, offer parents a choice in public education. High quality educational options that provide a safe and nurturing environment for students and encourage personal growth and academic achievements are needed in Missouri

    A Qualitative Case Study on Parental Involvement in a Midwestern Urban Charter School District: Perspectives of Parents, Teachers, and Administrators

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    Research has shown that there can be a positive impact on the child’s academic achievement when parents are closely involved with the child’s schooling. When parents are involved in the school, they understand what is being taught in the classroom and are usually encouraged to extend the learning at home. When parents value education, students succeed. When parents are invested and show an interest in their child’s school, they develop a sense of pride for the school and tend to support the school and teachers in their decisions. This cooperative attitude allows for better, open communication and a team attitude to develop amongst the school community. When children see parents, teachers, and administrators working together, they feel more positive pressure to do well. When parents are not involved in their child’s schooling, miscommunication, misunderstandings and problems arise. Parents do not understand or value what the school is teaching students, and children see the conflict as a barrier. Children typically mirror their parents’ beliefs and actions. Therefore, if a parent does not see the value in education, does not know what is being taught, and does not respect the school, administrators, or teachers, the child is likely to mirror those behaviors and attitudes. When this happens, students suffer academically. The concern about parent involvement is not new. Many schools understand the importance of parental involvement, but struggle to find the time, resources, and activities to involve parents. Oftentimes, urban areas contain families that have unique obstacles that prevent such involvement. Many strategies need to be utilized in order to ensure that parents are not left out of activities or opportunities. iii The purpose of this qualitative study was to determine the actions taken by one particular charter school district that led to intense parental involvement participation in an urban, metropolitan area. Understanding the obstacles that parents face when becoming involved was a starting point for the research. Understanding how the school utilized particular strategies to form solid relationships with families was vital to the study. Comparing administrator, teacher, and parent perceptions about the school’s parental involvement concluded the research

    Ambient ammonia measurements using laser photo-acoustic spectroscopy

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    Ammonia concentrations reached minimal levels (approximately 0.1 ppb) in early winter, followed by a sudden later winter increase. A direct relationship between ambient ammonia levels and air temperature was inferred from the data (linear correlation coefficient r=0.53). Ammonia concentrations were determined to be directly related to the absolute humidity of the air (r=0.72); a weaker relationship between ammonia concentrations and relative humidity was discovered (r=0.37). The data also indicated that ammonia levels were generally higher within continental air masses than those of maritime origin. Soil parameters such as pH and moisture content were found to have a major bearing on the release of gaseous ammonia from soils in the region

    Mixing with the radiofrequency single-electron transistor

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    By configuring a radio-frequency single-electron transistor as a mixer, we demonstrate a unique implementation of this device, that achieves good charge sensitivity with large bandwidth about a tunable center frequency. In our implementation we achieve a measurement bandwidth of 16 MHz, with a tunable center frequency from 0 to 1.2 GHz, demonstrated with the transistor operating at 300 mK. Ultimately this device is limited in center frequency by the RC time of the transistor's center island, which for our device is ~ 1.6 GHz, close to the measured value. The measurement bandwidth is determined by the quality factor of the readout tank circuit.Comment: Submitted to APL september 200

    Noise-enabled precision measurements of a Duffing nanomechanical resonator

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    We report quantitative experimental measurements of the nonlinear response of a radiofrequency mechanical resonator, with very high quality factor, driven by a large swept-frequency force. We directly measure the noise-free transition dynamics between the two basins of attraction that appear in the nonlinear regime, and find good agreement with those predicted by the one-dimensional Duffing equation of motion. We then measure the response of the transition rates to controlled levels of white noise, and extract the activation energy from each basin. The measurements of the noise-induced transitions allow us to obtain precise values for the critical frequencies, the natural resonance frequency, and the cubic nonlinear parameter in the Duffing oscillator, with direct applications to high sensitivity parametric sensors based on these resonators.Comment: 5 pages, 5 figure

    Hierarchical Collective Agent Network (HCAN) for efficient 3 fusion and management of multiple networked sensors

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    Agent-based software systems and applications are constructed by integrating diverse sets of components that are intelligent, heterogeneous, distributed, and concurrent. This paper describes a multi-agent system to assure the operation efficiency and reliability in data fusion and management of a set of networked distributive sensors (NDS). We discuss the general concept and architecture of a Hierarchical Collective Agent Network (HCAN) and its functional components for learning and adaptive control of the NDS. Sophistication of a HCAN control environment and an anatomy of the agent modules for enabling intelligent data fusion and management are presented. An exemplar HCAN is configured to support dynamic data fusion and automated sensor management in a simulated distributive and collaborative military sensor network for Global Missile Defense (GMD) application

    Bone health in adult women with ED: A longitudinal community-based study

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    Although Eating Disorders (ED) are known to affect bone health and development, little is known about the longitudinal effect of ED and ED behaviours on bone health in community dwelling adult women. Women (n = 3507) enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) participated in a two-phase prevalence study to assess lifetime ED and ED behaviours (fasting, restrictive eating, vomiting and misuse of medication). Crude and adjusted linear regression methods investigated the association between ED diagnoses and behaviours, and total body, hip, leg and arm bone mineral density (BMD) DXA scans at mean ages of 48 and 52 years. Lifetime occurrence of Anorexia Nervosa (AN) was associated with lower BMD Z-scores for the whole body (mean difference (MD) = −0.28; 95% CI: -0.49, −0.05), hip (MD = −0.45; 95% CI -0.74, −0.16), leg (MD = −0.28; 95% CI -0.52, −0.03) and arm (MD = −0.44; 95% CI -0.68, −0.19) compared to no ED. This effect was mostly accounted for by lowest ever BMI. In post-hoc analyses, Restrictive AN, but not Binge-Purge AN was associated with a lower total body BMD Z-scores (MD = −0.37; 95% CI -0.62, −0.12). Lifetime Fasting and Restrictive Eating were associated with low BMD of the total body, hip, arm and leg in adjusted analyses, all p < 0.05. Both lifetime ED diagnoses and ED behaviours in a large community sample were predictive of low BMD in mid-life. This study confirms that the effects of AN, fasting and restrictive eating, and low BMI on bone health seen in clinical samples also occur in community samples
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