Sample records for achieving optimal growth

  1. Regulating thrombus growth and stability to achieve an optimal response to injury

    PubMed Central

    Brass, Lawrence F.; Wannemacher, Kenneth M.; Ma, Peisong; Stalker, Timothy J.

    2012-01-01

    An optimal platelet response to injury can be defined as one in which blood loss is restrained and haemostasis is achieved without the penalty of further tissue damage caused by unwarranted vascular occlusion. This brief review considers some of the ways in which thrombus growth and stability can be regulated so that an optimal platelet response can be achieved in vivo. Three related topics are considered. The first focuses on intracellular mechanisms that regulate the early events of platelet activation downstream of G protein coupled receptors for agonists such as thrombin, thromboxane A2 and ADP. The second considers the ways in which signalling events that are dependent on stable contacts between platelets can influence the state of platelet activation and thus affect thrombus growth and stability. The third focuses on the changes that are experienced by platelets as they move from their normal environment in freely-flowing plasma to a very different environment within the growing haemostatic plug, an environment in which the narrowing gaps and junctions between platelets not only facilitate communication, but also increasingly limit both the penetration of plasma and the exodus of platelet-derived bioactive molecules. PMID:21781243

  2. The Growth Patterns of General Medical Achievement.

    ERIC Educational Resources Information Center

    Shen, Linjun

    This longitudinal study investigates the growth of medical achievement as a multilevel process and emphasizes the structure of the growth. Subjects were students in all 15 U.S. osteopathic medical schools, a total of 1,060 (78 percent of the 1987 osteopathic cohort). Students took appropriate portions of the National Board of Osteopathic Medical…

  3. Student Achievement and National Economic Growth

    ERIC Educational Resources Information Center

    Ramirez, Francisco O.; Luo, Xiaowei; Schofer, Evan; Meyer, John W.

    2006-01-01

    Educational policy around the world has increasingly focused on improving aggregate student achievement as a means to increase economic growth. In the last two decades, attention has focused especially on the importance of achievement in science and mathematics. Yet, the policy commitments involved have not been based on research evidence. The…

  4. Mathematics Coursework Regulates Growth in Mathematics Achievement

    ERIC Educational Resources Information Center

    Ma, Xin; Wilkins, Jesse L. M.

    2007-01-01

    Using data from the Longitudinal Study of American Youth (LSAY), we examined the extent to which students' mathematics coursework regulates (influences) the rate of growth in mathematics achievement during middle and high school. Graphical analysis showed that students who started middle school with higher achievement took individual mathematics…

  5. Optimism versus Pessimism and Academic Achievement Evaluation

    ERIC Educational Resources Information Center

    Harpaz-Itay, Yifat; Kaniel, Shlomo

    2012-01-01

    This article integrates three central theories of optimism-pessimism (OP). The combination of the shared components of these theories--outcome expectancies, emotions, and behavioral intention--may produce an integrative academic achievement evaluation. Little has been written regarding the differentiation between general and domain-specific OP, a…

  6. Insurance and Optimal Growth Frdric Gannon

    E-print Network

    Paris-Sud XI, Université de

    Insurance and Optimal Growth Frédéric Gannon (Université du Havre and EconomiX, France) Vincent connection be- tween insurance and economic growth. We develop a simple model to insert microeconomically founded optimal insurance with moral haz- ard in a standard macroeconomic framework of optimal growth. We

  7. The Effects of Academic Optimism on Elementary Reading Achievement

    ERIC Educational Resources Information Center

    Bevel, Raymona K.; Mitchell, Roxanne M.

    2012-01-01

    Purpose: The purpose of this paper is to explore the relationship between academic optimism (AO) and elementary reading achievement (RA). Design/methodology/approach: Using correlation and hierarchical linear regression, the authors examined school-level effects of AO on fifth grade reading achievement in 29 elementary schools in Alabama.…

  8. Schools, School Quality and Achievement Growth: Evidence from the Philippines

    ERIC Educational Resources Information Center

    Bacolod, Marigee P.; Tobias, Justin L.

    2006-01-01

    A broad literature seeks to assess the importance of schools, proxies for school quality, and family background on children's achievement growth using the education production function. Using rich data from the Philippines, we introduce and estimate a model that imposes little structure on the relationship between intake achievement and follow-up…

  9. Parent involvement and science achievement: A latent growth curve analysis

    NASA Astrophysics Data System (ADS)

    Johnson, Ursula Yvette

    This study examined science achievement growth across elementary and middle school and parent school involvement using the Early Childhood Longitudinal Study - Kindergarten Class of 1998--1999 (ECLS-K). The ECLS-K is a nationally representative kindergarten cohort of students from public and private schools who attended full-day or half-day kindergarten class in 1998--1999. The present study's sample (N = 8,070) was based on students that had a sampling weight available from the public-use data file. Students were assessed in science achievement at third, fifth, and eighth grades and parents of the students were surveyed at the same time points. Analyses using latent growth curve modeling with time invariant and varying covariates in an SEM framework revealed a positive relationship between science achievement and parent involvement at eighth grade. Furthermore, there were gender and racial/ethnic differences in parents' school involvement as a predictor of science achievement. Findings indicated that students with lower initial science achievement scores had a faster rate of growth across time. The achievement gap between low and high achievers in earth, space and life sciences lessened from elementary to middle school. Parents' involvement with school usually tapers off after elementary school, but due to parent school involvement being a significant predictor of eighth grade science achievement, later school involvement may need to be supported and better implemented in secondary schooling.

  10. Academic Optimism and Student Achievement in Urban Elementary Schools

    ERIC Educational Resources Information Center

    Smith, Page A.; Hoy, Wayne K.

    2007-01-01

    Purpose: The aim of this study was two-fold: to demonstrate a general construct of schools called academic optimism and to show it was related to student achievement in urban elementary schools, even controlling for socioeconomic factors, and school size. Design/methodology/approach: Data were collected from 99 urban elementary schools in Texas…

  11. Parent Involvement and Science Achievement: A Latent Growth Curve Analysis

    ERIC Educational Resources Information Center

    Johnson, Ursula Yvette

    2011-01-01

    This study examined science achievement growth across elementary and middle school and parent school involvement using the Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999 (ECLS-K). The ECLS-K is a nationally representative kindergarten cohort of students from public and private schools who attended full-day or half-day…

  12. Optimized Delivery System Achieves Enhanced Endomyocardial Stem Cell Retention

    PubMed Central

    Behfar, Atta; Latere, Jean-Pierre; Bartunek, Jozef; Homsy, Christian; Daro, Dorothee; Crespo-Diaz, Ruben J.; Stalboerger, Paul G.; Steenwinckel, Valerie; Seron, Aymeric; Redfield, Margaret M.; Terzic, Andre

    2014-01-01

    Background Regenerative cell-based therapies are associated with limited myocardial retention of delivered stem cells. The objective of this study is to develop an endocardial delivery system for enhanced cell retention. Methods and Results Stem cell retention was simulated in silico using one and three-dimensional models of tissue distortion and compliance associated with delivery. Needle designs, predicted to be optimal, were accordingly engineered using nitinol – a nickel and titanium alloy displaying shape memory and super-elasticity. Biocompatibility was tested with human mesenchymal stem cells. Experimental validation was performed with species-matched cells directly delivered into Langendorff-perfused porcine hearts or administered percutaneously into the endocardium of infarcted pigs. Cell retention was quantified by flow cytometry and real time quantitative polymerase chain reaction methodology. Models, computing optimal distribution of distortion calibrated to favor tissue compliance, predicted that a 75°-curved needle featuring small-to-large graded side holes would ensure the highest cell retention profile. In isolated hearts, the nitinol curved needle catheter (C-Cath) design ensured 3-fold superior stem cell retention compared to a standard needle. In the setting of chronic infarction, percutaneous delivery of stem cells with C-Cath yielded a 37.7±7.1% versus 10.0±2.8% retention achieved with a traditional needle, without impact on biocompatibility or safety. Conclusions Modeling guided development of a nitinol-based curved needle delivery system with incremental side holes achieved enhanced myocardial stem cell retention. PMID:24326777

  13. Translational Geroscience: Emphasizing function to achieve optimal longevity

    PubMed Central

    Seals, Douglas R.; Melov, Simon

    2014-01-01

    Among individuals, biological aging leads to cellular and organismal dysfunction and an increased risk of chronic degenerative diseases and disability. This sequence of events in combination with the projected increases in the number of older adults will result in a worldwide healthcare burden with dire consequences. Superimposed on this setting are the adults now reaching traditional retirement ages--the baby boomers--a group that wishes to remain active, productive and physically and cognitively fit as they grow older. Together, these conditions are producing an unprecedented demand for increased healthspan or what might be termed “optimal longevity”—to live long, but well. To meet this demand, investigators with interests in the biological aspects of aging from model organisms to human epidemiology (population aging) must work together within an interactive process that we describe as translational geroscience. An essential goal of this new investigational platform should be the optimization and preservation of physiological function throughout the lifespan, including integrative physical and cognitive function, which would serve to increase healthspan, compress morbidity and disability into a shorter period of late-life, and help achieve optimal longevity. To most effectively utilize this new approach, we must rethink how investigators and administrators working at different levels of the translational research continuum communicate and collaborate with each other, how best to train the next generation of scientists in this new field, and how contemporary biological-biomedical aging research should be organized and funded. PMID:25324468

  14. Translational geroscience: emphasizing function to achieve optimal longevity.

    PubMed

    Seals, Douglas R; Melov, Simon

    2014-09-01

    Among individuals, biological aging leads to cellular and organismal dysfunction and an increased risk of chronic degenerative diseases and disability. This sequence of events in combination with the projected increases in the number of older adults will result in a worldwide healthcare burden with dire consequences. Superimposed on this setting are the adults now reaching traditional retirement ages--the baby boomers--a group that wishes to remain active, productive and physically and cognitively fit as they grow older. Together, these conditions are producing an unprecedented demand for increased healthspan or what might be termed "optimal longevity"-to live long, but well. To meet this demand, investigators with interests in the biological aspects of aging from model organisms to human epidemiology (population aging) must work together within an interactive process that we describe astranslational geroscience. An essential goal of this new investigational platform should be the optimization and preservation of physiological function throughout the lifespan, including integrative physical and cognitive function, which would serve to increase healthspan, compress morbidity and disability into a shorter period of late-life, and help achieve optimal longevity. To most effectively utilize this new approach, we must rethink how investigators and administrators working at different levels of the translational research continuum communicate and collaborate with each other, how best to train the next generation of scientists in this new field, and how contemporary biological-biomedical aging research should be organized and funded. PMID:25324468

  15. Adaptation to Optimal Cell Growth through Self-Organized Criticality Chikara Furusawa

    E-print Network

    Kaneko, Kunihiko

    Adaptation to Optimal Cell Growth through Self-Organized Criticality Chikara Furusawa Quantitative October 2011; published 15 May 2012) A simple cell model consisting of a catalytic reaction network is studied to show that cellular states are self-organized in a critical state for achieving optimal growth

  16. Differential Growth Trajectories for Achievement Among Children Retained in First Grade: A Growth Mixture Model

    PubMed Central

    Chen, Qi; Hughes, Jan N.; Kwok, Oi-Man

    2013-01-01

    The authors investigated the differential effect of retention on the development of academic achievement from grade one to five on children retained in first grade over six years. Growth Mixture Model (GMM) analyses supported the existence of two distinct trajectory groups of retained children for both reading and math among 125 ethnically and linguistically diverse retained children. For each achievement domain, a low intercept/higher growth group (Class 1) and a high intercept/slower growth group (Class 2) were identified. Furthermore, Class 1 children were found to score lower on several measures of learning related skills (LRS) variables and were characterized by having poorer self-regulation and less prosocial behaviors, compared to the other group. Findings suggest that some children appear to benefit more from retention, in terms of higher reading and math growth, than others. Study findings have implications for selecting children into retention intervention and early intervention. PMID:24771882

  17. Differential Growth Trajectories for Achievement Among Children Retained in First Grade: A Growth Mixture Model.

    PubMed

    Chen, Qi; Hughes, Jan N; Kwok, Oi-Man

    2014-03-01

    The authors investigated the differential effect of retention on the development of academic achievement from grade one to five on children retained in first grade over six years. Growth Mixture Model (GMM) analyses supported the existence of two distinct trajectory groups of retained children for both reading and math among 125 ethnically and linguistically diverse retained children. For each achievement domain, a low intercept/higher growth group (Class 1) and a high intercept/slower growth group (Class 2) were identified. Furthermore, Class 1 children were found to score lower on several measures of learning related skills (LRS) variables and were characterized by having poorer self-regulation and less prosocial behaviors, compared to the other group. Findings suggest that some children appear to benefit more from retention, in terms of higher reading and math growth, than others. Study findings have implications for selecting children into retention intervention and early intervention. PMID:24771882

  18. Achieving an optimal outcome for medial pedicle vertical breast reduction.

    PubMed

    Pu, Lee L Q

    2014-09-01

    Breast reduction is a common procedure performed by plastic surgeons for functional or cosmetic improvement of the breast. However, final outcome can be less satisfactory to patients in terms of the size, shape, symmetry, scarring, or wound healing complications. However, good to excellent outcome after breast reduction can be accomplished by plastic surgeons once they have mastered their technique. The medial pedicle vertical breast reduction has been popularized recently. However, the technique is technically more complex, and the results have been less inconsistent with a learning curve. In addition, the technique has been criticized for a residual deformity in the lower pole of the breast and resulted in a high revision rate. In this article, key components for the medial pedicle vertical breast reduction including patient selection and technical refinements are discussed in details. The author describes his philosophy in patient selection, preoperative and intraoperative markings of the breast, and step-by-step surgical procedures with several technical refinements for the medical pedicle vertical breast reduction. In addition, the pearls for achieving an optimal outcome of such a breast reduction are also discussed. PMID:25003451

  19. Differential Growth Trajectories for Achievement among Children Retained in First Grade: A Growth Mixture Model

    ERIC Educational Resources Information Center

    Chen, Qi; Hughes, Jan N.; Kwok, Oi-Man

    2014-01-01

    The authors investigated the differential effect of retention on the development of academic achievement from grades 1 to 5 on children retained in grade 1 over 6 years. Growth mixture model (GMM) analyses supported the existence of two distinct trajectory groups of retained children for both reading and math among 125 ethnically and…

  20. WFH: closing the global gap--achieving optimal care.

    PubMed

    Skinner, Mark W

    2012-07-01

    For 50 years, the World Federation of Hemophilia (WFH) has been working globally to close the gap in care and to achieve Treatment for All patients, men and women, with haemophilia and other inherited bleeding disorders, regardless of where they might live. The WFH estimates that more than one in 1000 men and women has a bleeding disorder equating to 6,900,000 worldwide. To close the gap in care between developed and developing nations a continued focus on the successful strategies deployed heretofore will be required. However, in response to the rapid advances in treatment and emerging therapeutic advances on the horizon it will also require fresh approaches and renewed strategic thinking. It is difficult to predict what each therapeutic advance on the horizon will mean for the future, but there is no doubt that we are in a golden age of research and development, which has the prospect of revolutionizing treatment once again. An improved understanding of "optimal" treatment is fundamental to the continued evolution of global care. The challenges of answering government and payer demands for evidence-based medicine, and cost justification for the introduction and enhancement of treatment, are ever-present and growing. To sustain and improve care it is critical to build the body of outcome data for individual patients, within haemophilia treatment centers (HTCs), nationally, regionally and globally. Emerging therapeutic advances (longer half-life therapies and gene transfer) should not be justified or brought to market based only on the notion that they will be economically more affordable, although that may be the case, but rather more importantly that they will be therapeutically more advantageous. Improvements in treatment adherence, reductions in bleeding frequency (including microhemorrhages), better management of trough levels, and improved health outcomes (including quality of life) should be the foremost considerations. As part of a new WFH strategic plan (2012-2014) the WFH has identified several key initiatives for particular emphasis - continuation of the Global Alliance for Progress (GAP) program, a new initiative to address underserved countries and regions (The Cornerstone Initiative), enhancing health outcomes research and analysis, and a new research mentorship program. Despite our progress to date in closing the global gap in care, our work is not complete. Too many patients remain undiagnosed and too few receive adequate treatment. This paper will also discuss historical, present and future challenges and opportunities to close the gap in care and achieve Treatment for All. PMID:22726075

  1. The optimal polarizations for achieving maximum contrast in radar images

    NASA Technical Reports Server (NTRS)

    Swartz, A. A.; Yueh, H. A.; Kong, J. A.; Novak, L. M.; Shin, R. T.

    1988-01-01

    There is considerable interest in determining the optimal polarizations that maximize contrast between two scattering classes in polarimetric radar images. A systematic approach is presented for obtaining the optimal polarimetric matched filter, i.e., that filter which produces maximum contrast between two scattering classes. The maximization procedure involves solving an eigenvalue problem where the eigenvector corresponding to the maximum contrast ratio is an optimal polarimetric matched filter. To exhibit the physical significance of this filter, it is transformed into its associated transmitting and receiving polarization states, written in terms of horizontal and vertical vector components. For the special case where the transmitting polarization is fixed, the receiving polarization which maximizes the contrast ratio is also obtained. Polarimetric filtering is then applies to synthetic aperture radar images obtained from the Jet Propulsion Laboratory. It is shown, both numerically and through the use of radar imagery, that maximum image contrast can be realized when data is processed with the optimal polarimeter matched filter.

  2. The nexus between achieving the Millennium Development Goals and economic growth: the role of policy

    Microsoft Academic Search

    Hiren Sarkar

    2007-01-01

    Achieving the Millennium Development Goals is increasingly being accepted as a major development objective in Asian and Pacific countries. In this paper, it is argued that, in order to fulfill this objective, attention needs to be paid to the nexus between achieving the Goals and economic growth. Pro-growth MDGs are as important as pro-MDG growth. Appropriate macroeconomic and sectoral policies

  3. Achieving the “Low Carbon, Green Growth” Vision in Korea

    Microsoft Academic Search

    Randall S. Jones; Byungseo Yoo

    2012-01-01

    Korea, which has had the highest growth rate of greenhouse gas emissions in the OECD area since 1990, adopted an ambitious Green Growth Strategy in 2009. It aims at reducing emissions by 30% by 2020 relative to a “business as usual” scenario, implying a 4% cut from the 2005 level. The Strategy also includes a Five-Year Plan with public spending

  4. Growth and gaps in mathematics achievement of students with and without disabilities on a statewide achievement test.

    PubMed

    Stevens, Joseph J; Schulte, Ann C; Elliott, Stephen N; Nese, Joseph F T; Tindal, Gerald

    2015-02-01

    This study estimated mathematics achievement growth trajectories in a statewide sample of 92,045 students with and without disabilities over Grades 3 to 7. Students with disabilities (SWDs) were identified in seven exceptionality categories. Students without disabilities (SWoDs) were categorized as General Education (GE) or Academically/Intellectually Gifted (AIG). Students in all groups showed significant growth that decelerated over grades as well as significant variability in achievement by student group, both at the initial assessment in Grade 3 and in rates of growth over time. Race/ethnicity, gender, parental education, free/reduced lunch status, and English language proficiency were also significant predictors of achievement. Effect size estimates showed substantial year-to-year growth that decreased over grades. Sizeable achievement gaps that were relatively stable over grades were observed between SWoDs and students in specific exceptionality categories. Our study also demonstrated the importance of statistically controlling for variation related to student demographic characteristics. Additional research is needed that expands on these results with the same and additional exceptionality groups. PMID:25636260

  5. Multidisciplinary optimization for engineering systems: Achievements and potential

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw

    1989-01-01

    The currently common sequential design process for engineering systems is likely to lead to suboptimal designs. Recently developed decomposition methods offer an alternative for coming closer to optimum by breaking the large task of system optimization into smaller, concurrently executed and, yet, coupled tasks, identified with engineering disciplines or subsystems. The hierarchic and non-hierarchic decompositions are discussed and illustrated by examples. An organization of a design process centered on the non-hierarchic decomposition is proposed.

  6. Oystercatchers use colour preference to achieve longer-term optimality.

    PubMed Central

    Nagarajan, R; Goss-Custard, J D; Lea, S E G

    2002-01-01

    The optimal diet model entails that foragers look beyond the individual prey encounter, to at least the level of intake rate across a bout of foraging, but optimization over a longer time remains controversial. In this paper, we show how oystercatchers increase their intake over the longer term using mussel colour as a cue. Wintering oystercatchers Haematopus ostralegus feed extensively on mussels Mytilus edulis in the estuaries of southern Britain. They show a marked preference for brown-shelled mussels over the commoner black-shelled morph, and we show that this enables them to maximize their rate of energy gain over a longer period than a single foraging bout. The brown and black mussels did not differ in ventral thickness and energy content, which are the main criteria for mussel selection and most important for short-term optimization. The brown mussels contained significantly less moisture, so by selecting them, oystercatchers could pack more mussel flesh into their limited oesophageal storage capacity. This enables them to increase their overall consumption during a feeding bout and increases their long-run energy gain rate, to an extent that is large enough to be significant for survival, especially during the short exposure of the mussel beds in winter. PMID:11886646

  7. Exploring Gains in Reading and Mathematics Achievement among Regular and Exceptional Students Using Growth Curve Modeling

    ERIC Educational Resources Information Center

    Shin, Tacksoo; Davison, Mark L.; Long, Jeffrey D.; Chan, Chi-Keung; Heistad, David

    2013-01-01

    Using four-wave longitudinal reading and mathematics data (4th to 7th grades) from a large urban school district, growth curve modeling was used as a tool for examining three research questions: Are achievement gaps closing in reading and mathematics? What are the associations between prior-achievement and growth across the reading and mathematics…

  8. Regulatory schemes to achieve optimal flux partitioning in bacterial metabolism

    NASA Astrophysics Data System (ADS)

    Tang, Lei-Han; Yang, Zhu; Hui, Sheng; Kim, Pan-Jun; Li, Xue-Fei; Hwa, Terence

    2012-02-01

    The flux balance analysis (FBA) offers a way to compute the optimal performance of a given metabolic network when the maximum incoming flux of nutrient molecules and other essential ingredients for biosynthesis are specified. Here we report a theoretical and computational analysis of the network structure and regulatory interactions in an E. coli cell. An automated scheme is devised to simplify the network topology and to enumerate the independent flux degrees of freedom. The network organization revealed by the scheme enables a detailed interpretation of the three layers of metabolic regulation known in the literature: i) independent transcriptional regulation of biosynthesis and salvage pathways to render the network tree-like under a given nutrient condition; ii) allosteric end-product inhibition of enzyme activity at entry points of synthesis pathways for metabolic flux partitioning according to consumption; iii) homeostasis of currency and carrier compounds to maintain sufficient supply of global commodities. Using the amino-acid synthesis pathways as an example, we show that the FBA result can be reproduced with suitable implementation of the three classes of regulatory interactions with literature evidence.

  9. Multiphase Nano-Composite Coatings for Achieving Energy Optimization

    SciTech Connect

    Dr. Jose Nainaparampil

    2012-03-26

    UES Inc. and ANL teamed in this work to develop novel coating systems for the protection of surfaces from thermal degradation mainly in two applications; Machining and Die casting. These coatings were specifically designed for the purpose by incorporating required material phases and the overall architecture, which led to reduce the energy usage and increase efficiency of the operations. Following the UES/ANL'Â?s feasibility work, the coatings were developed utilizing High power impulse magnetron sputtering (HiPMS) and Large area filtered arc deposition (LAFAD) techniques. Toughness, hardness and oxidation resistance: contrasting qualities have been mixed in the right proportion to attain the suitable material characteristic for the cause. Hafnium diboride (HfB2) based materials provided such a system and its properties were tamed to attain the right combination of toughness and hardness by working on the microstructure and architecture of coatings. An effective interfacing material (graded concentrations of topcoat) was also achieved in this work to provide the required adhesion between the substrate and the coating. Combination of an appropriate bond coat and a functional top coat provided the present thermal degradation resistant coating for cutting tools and die-casting applications. Laboratory level performance tests and industrial level application tests by partner companies (Beta Site Testing) were used for the development of these coatings.

  10. Optimal Impedance Control for Task Achievement in the Presence of Signal-dependent Noise

    E-print Network

    Osu, Rieko

    Optimal Impedance Control for Task Achievement in the Presence of Signal-dependent Noise Rieko Osu1/60): Optimal Impedance Control with TOPS- Corresponding Author Mitsuo Kawato ATR Computational Neuroscience Laboratories 2-2-2 Hikaridai, Seika-cho, Soraku-gun Kyoto, 619-0288 Japan email: kawato@atr.jp TEL: +81

  11. Principal Leadership: Creating a Culture of Academic Optimism to Improve Achievement for All Students

    ERIC Educational Resources Information Center

    McGuigan, Leigh; Hoy, Wayne K.

    2006-01-01

    Since the Coleman Report (1966), educational researchers have tried to identify school properties that make a difference in student achievement and overcome the negative influence of low socioeconomic status. We theorized that academic optimism was a latent construct that enhanced student achievement and that enabling school structure provided a…

  12. Optimization of heating conditions during Cz BGO crystal growth

    NASA Astrophysics Data System (ADS)

    Kolesnikov, A. V.; Galenin, E. P.; Sidletskiy, O. Ts.; Kalaev, V. V.

    2014-12-01

    We have studied the effect of geometrical and physical parameters of additional lower heater on thermal conditions during BGO growth by the Czochralski technique, in particular, on keeping flat melt/crystal interface during the whole growth process. Numerical simulation by CGSim software was used as an efficient tool for the analysis. After revealing optimal growth conditions and hot zone design by modeling, we have modified experimental growth setup and successfully improved crystal growth process in close agreement to modeling predictions.

  13. Optimization of lamp spectrum for vegetable growth

    NASA Technical Reports Server (NTRS)

    Prikupets, L. B.; Tikhomirov, A. A.

    1994-01-01

    An increase in the demand for and production of vegetables in the winter, mainly in northern and Siberian regions, inevitably leads to mass building of structures for growing plants under completely artificial conditions. An industrial lighting technology is required whose main parameters (spectrum, irradiance, photoperiod) should be assigned carefully and should uniquely determine, along with other important characteristics of the artificial climate, the productivity of the plant-production facility. The most widespread crops grown in our country under indoor conditions are cucumber and tomato plants, which account for more than 98% of the area in greenhouses. These plants are good prospects for growing completely under intense artificial lighting conditions (photocultures). Optimization of the main parameters of optical radiation when growing these plants is the most important task of achieving their profitable production. At present, considerable experience has been gained in studying the dependence of productivity of cucumber and tomato communities on irradiation conditions. Fundamental studies of the Agrophysical Research Institute of the Russian Academy of Sciences, Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences, Timiryazev Agricultural Academy, and other institutes create a good basis for a detailed study of the given problem. Commercial sources of radiation substantially differing in spectral characteristics in the region of photosynthetically active radiation (PAR) were used in the studies.

  14. Academic Achievement and Adolescent Drug Use: An Examination of Reciprocal Effects and Correlated Growth Trajectories

    ERIC Educational Resources Information Center

    Henry, Kimberly L.

    2010-01-01

    Background: The primary aim was to examine correlated growth trajectories and reciprocal effects between academic achievement and drug use over the course of junior high school. Methods: One hundred and three male and 98 female students from 3 rural junior high schools were surveyed 4 times over the course of 3 years. Dual trajectory latent growth…

  15. Parent Involvement and Science Achievement: A Cross-Classified Multilevel Latent Growth Curve Analysis

    ERIC Educational Resources Information Center

    Johnson, Ursula Y.; Hull, Darrell M.

    2014-01-01

    The authors examined science achievement growth at Grades 3, 5, and 8 and parent school involvement at the same time points using the Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999. Data were analyzed using cross-classified multilevel latent growth curve modeling with time invariant and varying covariates. School-based…

  16. Student course taking and teacher quality: their effects on achievement and growth

    Microsoft Academic Search

    Ronald H. Heck; Rochelle Mahoe

    2010-01-01

    Purpose – The purpose of this paper is to examine the relationship between high school students' curricular positions, their perceptions of the quality of their teachers, and school academic process variables on students' growth rates and ending achievement in mathematics and science. Design\\/methodology\\/approach – Multilevel latent curve modeling is used to examine students' growth trajectories using the National Longitudinal Educational

  17. IN SEARCH OF AN OPTIMAL DEBT RATIO FOR ECONOMIC GROWTH

    Microsoft Academic Search

    David J. Smyth; Yu Hsing

    1995-01-01

    This paper extends the work of Barro (1979), Eisner (1992), foines (1991), Sawhney and DiPietro (1994), and others and examines whether an optimal debt ratio exists that will maximize economic growth. The growth rate of real GDP is specified as a function of the debt ratio, the debt ratio squared, the growth rates of labor employment, capital services, money stock,

  18. Reading and math achievement profiles and longitudinal growth trajectories of children with an autism spectrum disorder.

    PubMed

    Wei, Xin; Christiano, Elizabeth R A; Yu, Jennifer W; Wagner, Mary; Spiker, Donna

    2015-02-01

    This study examined the reading and math achievement profiles and longitudinal growth trajectories of a nationally representative sample of children ages 6 through 9 with an autism spectrum disorder. Four distinct achievement profiles were identified: higher-achieving (39%), hyperlexia (9%), hypercalculia (20%) and lower-achieving (32%). Children with hypercalculia and lower-achieving profiles were more likely to be from low socioeconomic families and had lower functional cognitive skills than the higher-achieving profile. All four profiles lost ground in passage comprehension over time. Slower improvement occurred for the higher-achieving group on letter-word identification, the hyperlexia group on conversation abilities and the hypercalculia group on calculation and functional cognitive skills relative to the lower-achieving group. PMID:24449604

  19. Emergence of robust growth laws from optimal regulation of ribosome synthesis

    PubMed Central

    Scott, Matthew; Klumpp, Stefan; Mateescu, Eduard M; Hwa, Terence

    2014-01-01

    Bacteria must constantly adapt their growth to changes in nutrient availability; yet despite large-scale changes in protein expression associated with sensing, adaptation, and processing different environmental nutrients, simple growth laws connect the ribosome abundance and the growth rate. Here, we investigate the origin of these growth laws by analyzing the features of ribosomal regulation that coordinate proteome-wide expression changes with cell growth in a variety of nutrient conditions in the model organism Escherichia coli. We identify supply-driven feedforward activation of ribosomal protein synthesis as the key regulatory motif maximizing amino acid flux, and autonomously guiding a cell to achieve optimal growth in different environments. The growth laws emerge naturally from the robust regulatory strategy underlying growth rate control, irrespective of the details of the molecular implementation. The study highlights the interplay between phenomenological modeling and molecular mechanisms in uncovering fundamental operating constraints, with implications for endogenous and synthetic design of microorganisms. PMID:25149558

  20. Predictors of early growth in academic achievement: the head-toes-knees-shoulders task.

    PubMed

    McClelland, Megan M; Cameron, Claire E; Duncan, Robert; Bowles, Ryan P; Acock, Alan C; Miao, Alicia; Pratt, Megan E

    2014-01-01

    Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics. PMID:25071619

  1. Predictors of early growth in academic achievement: the head-toes-knees-shoulders task

    PubMed Central

    McClelland, Megan M.; Cameron, Claire E.; Duncan, Robert; Bowles, Ryan P.; Acock, Alan C.; Miao, Alicia; Pratt, Megan E.

    2014-01-01

    Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics. PMID:25071619

  2. Achieving Optimality and Fairness in Autonomous Demand Response: Benchmarks and Billing Mechanisms

    E-print Network

    Mohsenian-Rad, Hamed

    ) programs are implemented by utili- ties to control the energy consumption at the consumer side of the meter been used to help integrating renewable energy sources [5]. Autonomous DR systems are typically1 Achieving Optimality and Fairness in Autonomous Demand Response: Benchmarks and Billing

  3. Optimal resource allocation explains changes in the zebra mussel growth

    E-print Network

    Koz³owski, Jan

    Optimal resource allocation explains changes in the zebra mussel growth pattern through time Marcin of the invasive mussel Dreissena polymorpha collected twice at intervals of 5 to 39 years (approximately 1 through time with the relationships predicted by a published model of optimal resource allocation in zebra

  4. Influence of the Umbilical Cord Insertion Site on the Optimal Individual Birth Weight Achievement

    PubMed Central

    Dufour, Anaïs; Prot, Fabien; Feige, Jean-Jacques; Equy, Véronique; Alfaidy, Nadia; Gillois, Pierre; Hoffmann, Pascale

    2014-01-01

    Study Question. To determine whether the umbilical cord insertion site of singleton pregnancies could be linked to the newborn birth weight at term and its individual growth potential achievement. Material and Methods. A cohort study including 528 records of term neonates was performed. Each neonate was assessed for growth adjusted for gestational age according to the infant's growth potential using the AUDIPOG module. We considered two categories of umbilical cord insertions: central and peripheral. Intrauterine growth restriction was defined as birth weight below the 10th percentile. Statistical analysis was performed using Chi-square, Student's t test, Wilcoxon test, ANOVA, and logistic regression. Results. We observed a total of 343 centrally inserted cords versus 185 peripheral cords. There were twice as many smokers in the mothers of the peripheral category compared to the centrally inserted ones. More importantly, we demonstrated that only 17/343 (5.0%) of infants with central cord insertion were growth restricted, compared to 37/185 (20.0%) of the infants born with a peripheral insertion. Neonates with centrally inserted cord were significantly heavier. Conclusion. The umbilical cord insertion site of singleton pregnancies is associated with the newborn's birth weight at term and its individual growth potential achievement. PMID:24967357

  5. Optimal strategies for managing fetal growth restriction.

    PubMed

    Hernandez-Andrade, E

    2015-02-01

    Early dating of pregnancy by ultrasound is necessary to establish the adequate fetal growth. Customized or individualized estimation of fetal growth is probably a better option than population based curves to identify fetuses at a higher risk of perinatal complications. Biological maternal markers and placental evaluation might contribute in the identification of fetuses at risk of abnormal growth. There is no specific Doppler pattern of fetal deterioration; however, in early growth restriction it is mainly expressed in the umbilical artery, and in late growth restriction (>34 weeks) in the middle cerebral artery. Abnormal biophysical profile and/or non-stress test can be considered as acute signs of fetal decompensation. Magnetic resonance imaging can provide information of fetuses at risk of abnormal neurodevelopment. Neonatal body composition in low birthweight newborns can be used to identify children at risk of metabolic complications. Gestational age at delivery is the most important parameter associated with perinatal morbidity and mortality; however, waiting until the ductus venosus is severely abnormal might reduce the possibilities of survival of preterm fetuses with abnormal growth. PMID:25323420

  6. Incorporating Student Mobility in Achievement Growth Modeling: A Cross-Classified Multiple Membership Growth Curve Model

    ERIC Educational Resources Information Center

    Grady, Matthew W.; Beretvas, S. Natasha

    2010-01-01

    Multiple membership random effects models (MMREMs) have been developed for use in situations where individuals are members of multiple higher level organizational units. Despite their availability and the frequency with which multiple membership structures are encountered, no studies have extended the MMREM approach to hierarchical growth curve…

  7. Precollege science achievement growth: Racial-ethnic and gender differences in cognitive and psychosocial constructs

    NASA Astrophysics Data System (ADS)

    Muller, Patricia Ann

    The purpose of this study was to gain a more complete understanding of the differences in science, mathematics and engineering education among racial-ethnic and gender subgroups by exploring factors related to precollege science achievement growth rates. Using Hierarchical Linear Modeling (HLM) and multi-wave, longitudinal data from the first three waves of the National Education Longitudinal Study of 1988--1994 (NELS:88/94), this study examined precollege science achievement growth rates during the 8th to 10th grade period and the 10th to 12th grade period for African American males, African American females, Latino males, Latina females, Asian American males, Asian American females, White males and White females. For the 8th--10th grade period, previous grades were significantly and positively related to science achievement growth for all subgroups; and socio-economic status and high school program were significantly and positively related to science achievement growth for all subgroups except one (Latino males, and Asian American males respectively). For the 10th--12th grade period, the quantity of science courses completed (science units) was the only variable that was statistically significant for more than one racial-ethnic by gender subgroup. Science units taken were significantly and positively related to 10 th--12th grade growth rates for all racial-ethnic by gender subgroups except Latino males. Locus-of-control was the only cognitive or psychosocial factor included from Eccles, Adler, Futterman, Goff, Kaczala, Meece and Midgley's (1983) theoretical framework for achievement behaviors that appeared to exhibit any pattern across race-ethnicities. Locus-of-control was positively related to 8th--10 th grade science achievement growth for females across all racial-ethnic subgroups, as well as for African American males. However, for both the 8 th--10th grade and 10th--12 th grade periods, there was no consistency across racial-ethnic or gender subgroups in effects of the remaining cognitive and psychosocial factors on science achievement growth rates. Cognitive and psychosocial variables were statistically significant only for specific subgroups, and did not generally exhibit any commonalities across gender, or by race. The findings accentuated the importance of disaggregating data and analyses by both race-ethnicity and gender.

  8. Commissioning, Operation, Real Time Monitoring and Evaluation of Pilot: Achieving Optimal Performance through Building Commissioning

    E-print Network

    Pang,X.; Piette, M.A.; Hao,B.

    2014-01-01

    specific on LEED Cx” • “It’s better to provide more case studies and explain in more detail” • “Want to know how to Cx a control system” • “Should talk about how to adapt it to the building industry in China” 6 Cx Workshop Items Excellent Good Neutral Poor...BUILDINGS ENERGY EFFICIENCY CONSORTIUM U.S. - CHINA CLEAN ENERGY RESEARCH CENTER (CERC-BEE) E3: Commissioning, Operation, Real Time Monitoring and Evaluation of Pilot Achieving Optimal Performance through Building Commissioning Xiufeng Pang...

  9. Optimal growth conditions for Isochrysis galbana

    Microsoft Academic Search

    Drora Kaplan; Zvi Cohen; Aharon Abeliovich

    1986-01-01

    Environmental and nutritional growth conditions of the unicellular microalga Isochrysis galbana were studied under laboratory con- ditions. The information obtained was used for cultivating the alga in outdoor miniponds. Outdoor cultures stayed monoalgal and free of predators as long as the temperature did not fall below 19°C and the rate of dilution did not exceed 40 % of the culture's

  10. Optimized Growth of Human Embryonic Stem Cells

    Microsoft Academic Search

    Matthew A. Singer; Jacqui Johnson; Paul Bello; Robert Kovelman; Michelle Greene

    Human embryonic stem (ES) cells were first derived and cultured approximately 10 years ago, using essentially the same conditions\\u000a that were used at the time for mouse ES cells. These original culture conditions were clearly not optimal, and since that\\u000a time, several forces have driven improvements in human ES cell culture. These include the use of human and autologous feeder

  11. Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals

    NASA Astrophysics Data System (ADS)

    Fang, H. S.; Qiu, S. R.; Zheng, L. L.; Schaffers, K. I.; Tassano, J. B.; Caird, J. A.; Zhang, H.

    2008-08-01

    Yb:S-FAP [Yb 3+:Sr 5(PO 4) 3F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0 cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF 2-rich melts often encounters cracks during the post-growth cool-down stage. To suppress cracking during cool-down, a numerical simulation of the growth system was used to understand the correlation between the furnace power during cool-down and the radial temperature differences within the crystal. The critical radial temperature difference, above which the crystal cracks, has been determined by benchmarking the simulation results against experimental observations. Based on this comparison, an optimal three-stage ramp-down profile was implemented, which produced high-quality, crack-free Yb:S-FAP crystals.

  12. Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals

    SciTech Connect

    Fang, H; Qiu, S; Kheng, L; Schaffers, K; Tassano, J; Caird, J; Zhang, H

    2007-08-20

    Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0 cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF{sub 2}-rich melts often encounter cracks during the post growth cool down stage. To suppress cracking during cool down, a numerical simulation of the growth system was used to understand the correlation between the furnace power during cool down and the radial temperature differences within the crystal. The critical radial temperature difference, above which the crystal cracks, has been determined by benchmarking the simulation results against experimental observations. Based on this comparison, an optimal three-stage ramp-down profile was implemented and produced high quality, crack-free Yb:S-FAP crystals.

  13. Growth mixture modeling of academic achievement in children of varying birth weight risk.

    PubMed

    Espy, Kimberly Andrews; Fang, Hua; Charak, David; Minich, Nori; Taylor, H Gerry

    2009-07-01

    The extremes of birth weight and preterm birth are known to result in a host of adverse outcomes, yet studies to date largely have used cross-sectional designs and variable-centered methods to understand long-term sequelae. Growth mixture modeling (GMM) that utilizes an integrated person- and variable-centered approach was applied to identify latent classes of achievement from a cohort of school-age children born at varying birth weights. GMM analyses revealed 2 latent achievement classes for calculation, problem-solving, and decoding abilities. The classes differed substantively and persistently in proficiency and in growth trajectories. Birth weight was a robust predictor of class membership for the 2 mathematics achievement outcomes and a marginal predictor of class membership for decoding. Neither visuospatial-motor skills nor environmental risk at study entry added to class prediction for any of the achievement skills. Among children born preterm, neonatal medical variables predicted class membership uniquely beyond birth weight. More generally, GMM is useful in revealing coherence in the developmental patterns of academic achievement in children of varying weight at birth and is well suited to investigations of sources of heterogeneity. PMID:19586210

  14. Small and Medium Enterprise in India - Overcoming Policy Constraints to Achieving Rapid Growth in a Globalizing Economy

    Microsoft Academic Search

    Sebastian Morris; Rakesh Basant

    Sustained very high rate of growth (above 8% in the context today in India) would be able to achieve (since a labour productivity growth of 4 to 4.5 % is to be factored in) a labour absorption rate of 3.5 to 4% which is about a percent above the growth in the rate of the workforce. But slower growth of

  15. The old age security hypothesis and optimal population growth.

    PubMed

    Bental, B

    1989-03-01

    The application of the Samuelson-Diamond overlapping generations framework to the old age security hypothesis indicates that government intervention schemes can influence the relationship between population growth and capital accumulation. The most direct means of optimizing population growth is through taxes or subsidies that relate to the intergenerational transfer of wealth. A pay-as-you-go social security scheme, in which payment is predicated on the number of children the receiver has and is financed by taxes levied on the working population, emerges as the most likely intervention to produce the optimal steady state equilibrium. This system is able to correct any distortions the private sector may build into it. In contrast, a child support system, in which the government subsidizes or taxes workers according to their family size, can guarantee the optimal capital:labor ratio but not the optimal population growth rate. Thus, if the government seeks to decrease the population growth rate, the appropriate intervention is to levy a lump-sum social-security tax on workers and transfer the revenues to the old; the direction should be reversed if the goal is to increase population growth. Another alternative, a lump sum social security system, can guarantee optimal population growth but not a desirable capital:labor ratio. Finally, the introduction of money as a valued commodity into an economy with a high capital:labor ratio will also serve to decrease the population growth rate and solve the intergenerational transfer problem through the private sector without any need for government intervention. PMID:12342694

  16. Preoperative treatment planning with intraoperative optimization can achieve consistent high-quality implants in prostate brachytherapy

    SciTech Connect

    Kudchadker, Rajat J., E-mail: rkudchad@mdanderson.org [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Pugh, Thomas J. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Swanson, David A. [Department of Urology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Bruno, Teresa L.; Bolukbasi, Yasemin; Frank, Steven J. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

    2012-01-01

    Advances in brachytherapy treatment planning systems have allowed the opportunity for brachytherapy to be planned intraoperatively as well as preoperatively. The relative advantages and disadvantages of each approach have been the subject of extensive debate, and some contend that the intraoperative approach is vital to the delivery of optimal therapy. The purpose of this study was to determine whether high-quality permanent prostate implants can be achieved consistently using a preoperative planning approach that allows for, but does not necessitate, intraoperative optimization. To achieve this purpose, we reviewed the records of 100 men with intermediate-risk prostate cancer who had been prospectively treated with brachytherapy monotherapy between 2006 and 2009 at our institution. All patients were treated with iodine-125 stranded seeds; the planned target dose was 145 Gy. Only 8 patients required adjustments to the plan on the basis of intraoperative findings. Consistency and quality were assessed by calculating the correlation coefficient between the planned and implanted amounts of radioactivity and by examining the mean values of the dosimetric parameters obtained on preoperative and 30 days postoperative treatment planning. The amount of radioactivity implanted was essentially identical to that planned (mean planned radioactivity, 41.27 U vs. mean delivered radioactivity, 41.36 U; R{sup 2} = 0.99). The mean planned and day 30 prostate V100 values were 99.9% and 98.6%, respectively. The mean planned and day 30 prostate D90 values were 186.3 and 185.1 Gy, respectively. Consistent, high-quality prostate brachytherapy treatment plans can be achieved using a preoperative planning approach, mostly without the need for intraoperative optimization. Good quality assurance measures during simulation, treatment planning, implantation, and postimplant evaluation are paramount for achieving a high level of quality and consistency.

  17. Growth optimization procedures for the phytopathogen Xylella fastidiosa.

    PubMed

    Campanharo, João Carlos; Lemos, Manoel Victor Franco; Lemos, Eliana Gertrudes de Macedo

    2003-02-01

    For the first time, growth curves are shown for the phytopathogen Xylella fastidiosa on traditional growth media such as PW (periwinkle wilt), BCYE (buffered charcoal yeast extract), and on new ones such as GYE (glutamate yeast extract) and PYE (phosphate yeast extract) that were developed in this work. The optimal growth conditions on solid and liquid media as well as their measurements are presented, by using total protein content and turbidity determinations. The results demonstrated that yeast extract provided sufficient nutrients for X. fastidiosa, since the cells grew well on PYE medium. PMID:12520363

  18. Optimization of Dairy Sludge for Growth of Rhizobium Cells

    PubMed Central

    Singh, Ashok Kumar; Singh, Gauri; Gautam, Digvijay; Bedi, Manjinder Kaur

    2013-01-01

    In this study dairy sludge was evaluated as an alternative cultivation medium for Rhizobium. Growth of bacterial strains at different concentrations of Dairy sludge was monitored. Maximum growth of all strains was observed at 60% Dairy sludge concentration. At 60% optical density (OD) values are 0.804 for Rhizobium trifolii (MTCC905), 0.825 for Rhizobium trifolii (MTCC906), and 0.793 for Rhizobium meliloti (MTCC100). Growth pattern of strains was observed at 60% Dairy sludge along with different synthetic media (tryptone yeast, Rhizobium minimal medium and yeast extract mannitol). Growth in 60% Dairy sludge was found to be superior to standard media used for Rhizobium. Media were optimized using 60% dairy sludge along with different concentrations of yeast extract (1–7?g/L) and mannitol (7–13?g/L) in terms of optical density at different time intervals, that is, 24, 48 and 72 hours. Maximum growth was observed in 6?g/L of yeast extract and 12?g/L of mannitol at 48-hour incubation period in all strains. The important environmental parameters such as pH were optimized using 60% dairy sludge, 60% dairy sludge +6?g/L yeast extract, and 60% dairy sludge +12?g/L mannitol. The maximum growth of all strains was found at pH 7.0. The present study recommends the use of 60% dairy sludge as a suitable growth medum for inoculant production. PMID:24089690

  19. A tree-growth model to optimize silviculture Patrice Loisel

    E-print Network

    Boyer, Edmond

    of silviculture. Keywords : growth model ; optimization; control 1 Introduction The forest management, because management of several forest stands. As to foresters, they are moreover interested in silviculture, if by modifying parameters to take into account the climate change and analyzing so the potential consequences

  20. OPTIMAL GROWTH AND SECONDARY METABOLITE PRODUCTION FROM COTTON HAIRY ROOTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hairy root cultures are an ideal system to investigate metabolite production and regulation in cotton. As part of our studies on cotton hairy root cultures, experiments were conducted to optimize culture growth rate and secondary metabolity production. In addition to gossypol (a disesquiterpene wi...

  1. OPTIMAL GROWTH AND SECONDARY METABOLITE PRODUCTION FROM COTTON HAIRY ROOTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hairy root cultures are an ideal system to investigate metabolite production and regulation in cotton. As part of our studies on cotton hairy root cultures, experiments were conducted to optimize culture growth rate and secondary metabolite production. In addition to gossypol (a disesquiterpene with...

  2. Optimal resource allocation explains growth curve diversity in zebra mussels

    E-print Network

    Kramarz, Paulina

    Optimal resource allocation explains growth curve diversity in zebra mussels Marcin Czarnoleski, 1 of Podlasie, Prusa 12, 08-110 Siedlce, Poland ABSTRACT We analysed data on zebra mussels (Dreissena polymorpha of mortality to the production rate index in the empirical data. The results indicate that zebra mussels

  3. Flux Consumption Optimization and the Achievement of 1MA Discharge on NSTX

    SciTech Connect

    J. Menard; B. LeBlanc; S.A. Sabbagh; M. Bell; R. Bell; et al

    2000-11-16

    The spherical tokamak (ST), because of its slender central column, has very limited volt-second capability relative to a standard aspect ratio tokamak of similar plasma cross-section. Recent experiments on the National Spherical Torus Experiment (NSTX) have begun to quantify and optimize the ohmic current drive efficiency in a MA-class ST device. Sustainable ramp-rates in excess of 5MA/sec during the current rise phase have been achieved on NSTX, while faster ramps generate significant MHD activity. Discharges with IP exceeding 1MA have been achieved in NSTX with nominal parameters: aspect ratio A=1.3-1.4, elongation k=2-2.2, triangularity d=0.4, internal inductance li=0.6, and Ejima coefficient CE =0.35. Flux consumption efficiency results, performance improvements associated with first boronization, and comparisons to neo-classical resistivity are described.

  4. Using hierarchical linear growth models to evaluate protective mechanisms that mediate science achievement

    NASA Astrophysics Data System (ADS)

    von Secker, Clare Elaine

    The study of students at risk is a major topic of science education policy and discussion. Much research has focused on describing conditions and problems associated with the statistical risk of low science achievement among individuals who are members of groups characterized by problems such as poverty and social disadvantage. But outcomes attributed to these factors do not explain the nature and extent of mechanisms that account for differences in performance among individuals at risk. There is ample theoretical and empirical evidence that demographic differences should be conceptualized as social contexts, or collections of variables, that alter the psychological significance and social demands of life events, and affect subsequent relationships between risk and resilience. The hierarchical linear growth models used in this dissertation provide greater specification of the role of social context and the protective effects of attitude, expectations, parenting practices, peer influences, and learning opportunities on science achievement. While the individual influences of these protective factors on science achievement were small, their cumulative effect was substantial. Meta-analysis conducted on the effects associated with psychological and environmental processes that mediate risk mechanisms in sixteen social contexts revealed twenty-two significant differences between groups of students. Positive attitudes, high expectations, and more intense science course-taking had positive effects on achievement of all students, although these factors were not equally protective in all social contexts. In general, effects associated with authoritative parenting and peer influences were negative, regardless of social context. An evaluation comparing the performance and stability of hierarchical linear growth models with traditional repeated measures models is included as well.

  5. The controlled growth method - A tool for structural optimization

    NASA Technical Reports Server (NTRS)

    Hajela, P.; Sobieszczanski-Sobieski, J.

    1981-01-01

    An adaptive design variable linking scheme in a NLP based optimization algorithm is proposed and evaluated for feasibility of application. The present scheme, based on an intuitive effectiveness measure for each variable, differs from existing methodology in that a single dominant variable controls the growth of all others in a prescribed optimization cycle. The proposed method is implemented for truss assemblies and a wing box structure for stress, displacement and frequency constraints. Substantial reduction in computational time, even more so for structures under multiple load conditions, coupled with a minimal accompanying loss in accuracy, vindicates the algorithm.

  6. Predicting long-term growth in students' mathematics achievement: the unique contributions of motivation and cognitive strategies.

    PubMed

    Murayama, Kou; Pekrun, Reinhard; Lichtenfeld, Stephanie; Vom Hofe, Rudolf

    2013-01-01

    This research examined how motivation (perceived control, intrinsic motivation, and extrinsic motivation), cognitive learning strategies (deep and surface strategies), and intelligence jointly predict long-term growth in students' mathematics achievement over 5 years. Using longitudinal data from six annual waves (Grades 5 through 10; Mage  = 11.7 years at baseline; N = 3,530), latent growth curve modeling was employed to analyze growth in achievement. Results showed that the initial level of achievement was strongly related to intelligence, with motivation and cognitive strategies explaining additional variance. In contrast, intelligence had no relation with the growth of achievement over years, whereas motivation and learning strategies were predictors of growth. These findings highlight the importance of motivation and learning strategies in facilitating adolescents' development of mathematical competencies. PMID:23278807

  7. CCMR: Growth Parameter Optimization and Contact Printing of Germanium Nanowires

    NSDL National Science Digital Library

    Blood-Forsythe, Martin A.

    2008-08-15

    Germanium nanowires, grown by gold nanoparticle catalyzed chemical vapor deposition, are highly promissing building blocks for future electronic devices and are versatile components for a variety of optoelectronic studies. This project seeks to further optimize the growth paramenters for a variety of diameter nanowires and by use of contact printing and sonication, transfer these wires as an aligned array and a suspended solution of nanowires, for use in a THz probe spectroscopy study and a quantitative electron energy loss microscopy study.

  8. Achieving Conservation when Opportunity Costs Are High: Optimizing Reserve Design in Alberta's Oil Sands Region

    PubMed Central

    Schneider, Richard R.; Hauer, Grant; Farr, Dan; Adamowicz, W. L.; Boutin, Stan

    2011-01-01

    Recent studies have shown that conservation gains can be achieved when the spatial distributions of biological benefits and economic costs are incorporated in the conservation planning process. Using Alberta, Canada, as a case study we apply these techniques in the context of coarse-filter reserve design. Because targets for ecosystem representation and other coarse-filter design elements are difficult to define objectively we use a trade-off analysis to systematically explore the relationship between conservation targets and economic opportunity costs. We use the Marxan conservation planning software to generate reserve designs at each level of conservation target to ensure that our quantification of conservation and economic outcomes represents the optimal allocation of resources in each case. Opportunity cost is most affected by the ecological representation target and this relationship is nonlinear. Although petroleum resources are present throughout most of Alberta, and include highly valuable oil sands deposits, our analysis indicates that over 30% of public lands could be protected while maintaining access to more than 97% of the value of the region's resources. Our case study demonstrates that optimal resource allocation can be usefully employed to support strategic decision making in the context of land-use planning, even when conservation targets are not well defined. PMID:21858046

  9. Growth-defense tradeoffs in plants: a balancing act to optimize fitness.

    PubMed

    Huot, Bethany; Yao, Jian; Montgomery, Beronda L; He, Sheng Yang

    2014-08-01

    Growth-defense tradeoffs are thought to occur in plants due to resource restrictions, which demand prioritization towards either growth or defense, depending on external and internal factors. These tradeoffs have profound implications in agriculture and natural ecosystems, as both processes are vital for plant survival, reproduction, and, ultimately, plant fitness. While many of the molecular mechanisms underlying growth and defense tradeoffs remain to be elucidated, hormone crosstalk has emerged as a major player in regulating tradeoffs needed to achieve a balance. In this review, we cover recent advances in understanding growth-defense tradeoffs in plants as well as what is known regarding the underlying molecular mechanisms. Specifically, we address evidence supporting the growth-defense tradeoff concept, as well as known interactions between defense signaling and growth signaling. Understanding the molecular basis of these tradeoffs in plants should provide a foundation for the development of breeding strategies that optimize the growth-defense balance to maximize crop yield to meet rising global food and biofuel demands. PMID:24777989

  10. Effects of Schoolwide Cluster Grouping and within-Class Ability Grouping on Elementary School Students' Academic Achievement Growth

    ERIC Educational Resources Information Center

    Matthews, Michael S.; Ritchotte, Jennifer A.; McBee, Matthew T.

    2013-01-01

    We evaluated the effects of one year of schoolwide cluster grouping on the academic achievement growth of gifted and non-identified elementary students using a piecewise multilevel growth model. Scores from 186 non-identified and 68 gifted students' Measures of Academic Progress Reading and Math scores were examined over three school years.…

  11. Achievement growth in children with learning difficulties in mathematics: Findings of a two-year longitudinal study

    Microsoft Academic Search

    Nancy C. Jordon; David Kaplan; Laurie B. Hanich

    2002-01-01

    The reading and mathematics growth of 180 children was examined over 4 points, spanning 2nd and 3rd grades. Initially, 4 achievement groups were identified: difficulties in mathematics but not in reading (MD only), difficulties in mathematics as well as in reading (MD-RD), difficulties in reading but not in mathematics (RD only), and normal achievement in mathematics and in reading. When

  12. Academic abilities in children and adolescents with a history of autism spectrum disorders who have achieved optimal outcomes.

    PubMed

    Troyb, Eva; Orinstein, Alyssa; Tyson, Katherine; Helt, Molly; Eigsti, Inge-Marie; Stevens, Michael; Fein, Deborah

    2014-04-01

    This study examines the academic abilities of children and adolescents who were once diagnosed with an autism spectrum disorder, but who no longer meet diagnostic criteria for this disorder. These individuals have achieved social and language skills within the average range for their ages, receive little or no school support, and are referred to as having achieved "optimal outcomes." Performance of 32 individuals who achieved optimal outcomes, 41 high-functioning individuals with a current autism spectrum disorder diagnosis (high-functioning autism), and 34 typically developing peers was compared on measures of decoding, reading comprehension, mathematical problem solving, and written expression. Groups were matched on age, sex, and nonverbal IQ; however, the high-functioning autism group scored significantly lower than the optimal outcome and typically developing groups on verbal IQ. All three groups performed in the average range on all subtests measured, and no significant differences were found in performance of the optimal outcome and typically developing groups. The high-functioning autism group scored significantly lower on subtests of reading comprehension and mathematical problem solving than the optimal outcome group. These findings suggest that the academic abilities of individuals who achieved optimal outcomes are similar to those of their typically developing peers, even in areas where individuals who have retained their autism spectrum disorder diagnoses exhibit some ongoing difficulty. PMID:24096312

  13. Optimal control: its application to economic growth and natural resource depletion

    Microsoft Academic Search

    David N. Burghes; Robert Davison; George Yarrow

    1977-01-01

    The application of optimal control to economic growth and natural resource depletion is described in this paper. The basic equations of optimal control are introduced, and a simple model for economic growth is described. The optimal consumption path is then deteimined for this problem subject to the maximization of a welfare integral. The model is then generalized so that production

  14. Growth or reproduction: emergence of an evolutionary optimal strategy

    NASA Astrophysics Data System (ADS)

    Grilli, J.; Suweis, S.; Maritan, A.

    2013-10-01

    Modern ecology has re-emphasized the need for a quantitative understanding of the original ‘survival of the fittest theme’ based on analysis of the intricate trade-offs between competing evolutionary strategies that characterize the evolution of life. This is key to the understanding of species coexistence and ecosystem diversity under the omnipresent constraint of limited resources. In this work we propose an agent-based model replicating a community of interacting individuals, e.g. plants in a forest, where all are competing for the same finite amount of resources and each competitor is characterized by a specific growth-reproduction strategy. We show that such an evolution dynamics drives the system towards a stationary state characterized by an emergent optimal strategy, which in turn depends on the amount of available resources the ecosystem can rely on. We find that the share of resources used by individuals is power-law distributed with an exponent directly related to the optimal strategy. The model can be further generalized to devise optimal strategies in social and economical interacting systems dynamics.

  15. Optimal microelectromechanical systems (MEMS) device for achieving high pyroelectric response of AlN

    NASA Astrophysics Data System (ADS)

    Kebede, Bemnnet; Coutu, Ronald A.; Starman, LaVern

    2014-03-01

    This paper discusses research being conducted on aluminum nitride (AlN) as a pyroelectric material for use in detecting applications. AlN is being investigated because of its high pyroelectric coefficient, thermal stability, and high Curie temperature. In order to determine suitability of the pyroelectric properties of AlN for use as a detector, testing of several devices was conducted. These devices were fabricated using microelectromechanical systems (MEMS) fabrication processes; the devices were also designed to allow for voltage and current measurements. The deposited AlN films used were 150 nm - 300 nm in thickness. Thin-films were used to rapidly increase the temperature response after the thermal stimulus was applied to the pyroelectric material. This is important because the pyroelectric effect is directly proportional to the rate of temperature change. The design used was a face-electrode bridge that provides thermal isolation which minimizes heat loss to the substrate, thereby increasing operation frequency of the pyroelectric device. A thermal stimulus was applied to the pyroelectric material and the response was measured across the electrodes. A thermal imaging camera was used to monitor the changes in temperature. Throughout the testing process, the annealing temperatures, type of layers, and thicknesses were also varied. These changes resulted in improved MEMS designs, which were fabricated to obtain an optimal design configuration for achieving a high pyroelectric response. A pyroelectric voltage response of 38.9 mVp-p was measured without filtering, 12.45 mVp-p was measured in the infrared (IR) region using a Si filter, and 6.38 mVp-p was measured in the short wavelength IR region using a long pass filter. The results showed that AlN's pyroelectric properties can be used in detecting applications.

  16. Using Markov Models of Fault Growth Physics and Environmental Stresses to Optimize Control Actions

    NASA Technical Reports Server (NTRS)

    Bole, Brian; Goebel, Kai; Vachtsevanos, George

    2012-01-01

    A generalized Markov chain representation of fault dynamics is presented for the case that available modeling of fault growth physics and future environmental stresses can be represented by two independent stochastic process models. A contrived but representatively challenging example will be presented and analyzed, in which uncertainty in the modeling of fault growth physics is represented by a uniformly distributed dice throwing process, and a discrete random walk is used to represent uncertain modeling of future exogenous loading demands to be placed on the system. A finite horizon dynamic programming algorithm is used to solve for an optimal control policy over a finite time window for the case that stochastic models representing physics of failure and future environmental stresses are known, and the states of both stochastic processes are observable by implemented control routines. The fundamental limitations of optimization performed in the presence of uncertain modeling information are examined by comparing the outcomes obtained from simulations of an optimizing control policy with the outcomes that would be achievable if all modeling uncertainties were removed from the system.

  17. A Study of the Relationships between Distributed Leadership, Teacher Academic Optimism and Student Achievement in Taiwanese Elementary Schools

    ERIC Educational Resources Information Center

    Chang, I-Hua

    2011-01-01

    The purpose of this study was to explore the relationships between distributed leadership, teachers' academic optimism and student achievement in learning. The study targeted public elementary schools in Taiwan and adopted stratified random sampling to investigate 1500 teachers. Teachers' perceptions were collected by a self-report scale. In…

  18. Robust Airfoil Optimization to Achieve Consistent Drag Reduction Over a Mach Range

    NASA Technical Reports Server (NTRS)

    Li, Wu; Huyse, Luc; Padula, Sharon; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    We prove mathematically that in order to avoid point-optimization at the sampled design points for multipoint airfoil optimization, the number of design points must be greater than the number of free-design variables. To overcome point-optimization at the sampled design points, a robust airfoil optimization method (called the profile optimization method) is developed and analyzed. This optimization method aims at a consistent drag reduction over a given Mach range and has three advantages: (a) it prevents severe degradation in the off-design performance by using a smart descent direction in each optimization iteration, (b) there is no random airfoil shape distortion for any iterate it generates, and (c) it allows a designer to make a trade-off between a truly optimized airfoil and the amount of computing time consumed. For illustration purposes, we use the profile optimization method to solve a lift-constrained drag minimization problem for 2-D airfoil in Euler flow with 20 free-design variables. A comparison with other airfoil optimization methods is also included.

  19. Academic achievement of homeless and highly mobile children in an urban school district: longitudinal evidence on risk, growth, and resilience.

    PubMed

    Obradovi?, Jelena; Long, Jeffrey D; Cutuli, J J; Chan, Chi-Keung; Hinz, Elizabeth; Heistad, David; Masten, Ann S

    2009-01-01

    Longitudinal growth trajectories of reading and math achievement were studied in four primary school grade cohorts (GCs) of a large urban district to examine academic risk and resilience in homeless and highly mobile (H/HM) students. Initial achievement was assessed when student cohorts were in the second, third, fourth, and fifth grades, and again 12 and 18 months later. Achievement trajectories of H/HM students were compared to low-income but nonmobile students and all other tested students in the district, controlling for four well-established covariates of achievement: sex, ethnicity, attendance, and English language skills. Both disadvantaged groups showed markedly lower initial achievement than their more advantaged peers, and H/HM students manifested the greatest risk, consistent with an expected risk gradient. Moreover, in some GCs, both disadvantaged groups showed slower growth than their relatively advantaged peers. Closer examination of H/HM student trajectories in relation to national test norms revealed striking variability, including cases of academic resilience as well as problems. H/HM students may represent a major component of "achievement gaps" in urban districts, but these students also constitute a heterogeneous group of children likely to have markedly diverse educational needs. Efforts to close gaps or enhance achievement in H/HM children require more differentiated knowledge of vulnerability and protective processes that may shape individual development and achievement. PMID:19338695

  20. An optimal model for microbial growth in a multiple substrate environment: simultaneous and sequential utilization

    Microsoft Academic Search

    Pankaj Doshi; K. V. Venkatesh

    1998-01-01

    A comprehensive optimal model has been developed to simulate microbial growth for simultaneous utilization of mixture of three substrate. The optimal strategy used to model microbial growth, which was developed by Venkatesh et al. (Biotechnology and Bioengineering56(6) 635–644, 1997) is extended to represent simultaneous and sequential growth phenomenon. The model prediction matches closely with the experimental growth data of Escherichia

  1. Designing adaptive antenna uplink weighting vector to achieve optimization of radiation pattern

    Microsoft Academic Search

    Chao-Hsing Hsu; Tadeusz M. Babij

    2002-01-01

    In this paper, the optimal radiation pattern of an adaptive linear array is derived by phase-amplitude perturbations using a genetic algorithm. An antenna array is often used as an adaptive antenna. An optimal radiation pattern design for an adaptive antenna system is not only to suppress interference by placing a null in the direction of the interfering source but also

  2. An efficient framework for optimization and parameter sensitivity analysis in arterial growth and remodeling computations

    PubMed Central

    Sankaran, Sethuraman; Humphrey, Jay D.; Marsden, Alison L.

    2013-01-01

    Computational models for vascular growth and remodeling (G&R) are used to predict the long-term response of vessels to changes in pressure, flow, and other mechanical loading conditions. Accurate predictions of these responses are essential for understanding numerous disease processes. Such models require reliable inputs of numerous parameters, including material properties and growth rates, which are often experimentally derived, and inherently uncertain. While earlier methods have used a brute force approach, systematic uncertainty quantification in G&R models promises to provide much better information. In this work, we introduce an efficient framework for uncertainty quantification and optimal parameter selection, and illustrate it via several examples. First, an adaptive sparse grid stochastic collocation scheme is implemented in an established G&R solver to quantify parameter sensitivities, and near-linear scaling with the number of parameters is demonstrated. This non-intrusive and parallelizable algorithm is compared with standard sampling algorithms such as Monte-Carlo. Second, we determine optimal arterial wall material properties by applying robust optimization. We couple the G&R simulator with an adaptive sparse grid collocation approach and a derivative-free optimization algorithm. We show that an artery can achieve optimal homeostatic conditions over a range of alterations in pressure and flow; robustness of the solution is enforced by including uncertainty in loading conditions in the objective function. We then show that homeostatic intramural and wall shear stress is maintained for a wide range of material properties, though the time it takes to achieve this state varies. We also show that the intramural stress is robust and lies within 5% of its mean value for realistic variability of the material parameters. We observe that prestretch of elastin and collagen are most critical to maintaining homeostasis, while values of the material properties are most critical in determining response time. Finally, we outline several challenges to the G&R community for future work. We suggest that these tools provide the first systematic and efficient framework to quantify uncertainties and optimally identify G&R model parameters. PMID:23626380

  3. Release optimization of epidermal growth factor from PLGA microparticles.

    PubMed

    Mirdailami, Omolbanin; Khoshayand, Mohammad Reza; Soleimani, Masoud; Dinarvand, Rassoul; Atyabi, Fatemeh

    2014-08-01

    The objective of this study was to prepare poly lactic-co-glycolic acid (PLGA)-based microparticles as potential carriers for recombinant human epidermal growth factor (rhEGF). In order to optimize characteristic parameters of protein-loaded microspheres, bovine serum albumin (BSA) was selected as the model protein. To reduce burst release as a common problem of microspheres, a proper alteration in the particle composition was used, such as addition of poly vinyl alcohol and changes in initial drug loading. The effects of these parameters on particle size, encapsulation efficiency and in vitro release kinetics of BSA in PLGA microspheres were investigated using a Box-Behnken response surface methodology. The biological activity of the released rhEGF was assessed using human skin fibroblasts cell proliferation assay. The prepared rhEGF-loaded microspheres had an average size of 6.44 ± 2.45 µm, encapsulation efficiency of 97.04 ± 1.13%, burst release of 13.06 ± 1.35% and cumulative release of 22.56 ± 2.41%. The proliferation of human skin fibroblast cells cultivated with rhEGF releasate of microspheres was similar to that of pure rhEGF, indicating the biological activity of released protein confirming the stability of rhEGF during microsphere preparation. These results are in agreement with the purpose of our study to prepare rhEGF-entrapped PLGA microparticles with optimized characteristics. PMID:23777385

  4. A longitudinal analysis of gender differences in academic self-concept and language achievement: A multivariate multilevel latent growth approach

    Microsoft Academic Search

    Bieke De Fraine; Jan Van Damme; Patrick Onghena

    2007-01-01

    This study investigated the development of academic self-concept and language achievement from Grade 7 to Grade 12 by repeated assessment of 2826 Flemish adolescents in 50 secondary schools. Latent growth curve modeling showed that both girls and boys experience a declining academic self-concept during the period of secondary education and that girls declined at a faster rate. Furthermore, girls were

  5. Predicting Long-Term Growth in Students' Mathematics Achievement: The Unique Contributions of Motivation and Cognitive Strategies

    ERIC Educational Resources Information Center

    Murayama, Kou; Pekrun, Reinhard; Lichtenfeld, Stephanie; vom Hofe, Rudolf

    2013-01-01

    This research examined how motivation (perceived control, intrinsic motivation, and extrinsic motivation), cognitive learning strategies (deep and surface strategies), and intelligence jointly predict long-term growth in students' mathematics achievement over 5 years. Using longitudinal data from six annual waves (Grades 5 through 10;…

  6. Layered Plant-Growth Media for Optimizing Gaseous, Liquid and Nutrient Requirements: Modeling, Design and Monitoring

    NASA Astrophysics Data System (ADS)

    Heinse, R.; Jones, S. B.; Bingham, G.; Bugbee, B.

    2006-12-01

    Rigorous management of restricted root zones utilizing coarse-textured porous media greatly benefits from optimizing the gas-water balance within plant-growth media. Geophysical techniques can help to quantify root- zone parameters like water content, air-filled porosity, temperature and nutrient concentration to better address the root systems performance. The efficiency of plant growth amid high root densities and limited volumes is critically linked to maintaining a favorable water content/air-filled porosity balance while considering adequate fluxes to replenish water at decreasing hydraulic conductivities during uptake. Volumes adjacent to roots also need to be optimized to provide adequate nutrients throughout the plant's life cycle while avoiding excessive salt concentrations. Our objectives were to (1) design and model an optimized root zone system using optimized porous media layers, (2) verify our design by monitoring the water content distribution and tracking nutrient release and transport, and (3) mimic water and nutrient uptake using plants or wicks to draw water from the root system. We developed a unique root-zone system using layered Ottawa sands promoting vertically uniform water contents and air-filled porosities. Watering was achieved by maintaining a shallow saturated layer at the bottom of the column and allowing capillarity to draw water upward, where coarser particle sizes formed the bottom layers with finer particles sizes forming the layers above. The depth of each layer was designed to optimize water content based on measurements and modeling of the wetting water retention curves. Layer boundaries were chosen to retain saturation between 50 and 85 percent. The saturation distribution was verified by dual-probe heat-pulse water-content sensors. The nutrient experiment involved embedding slow release fertilizer in the porous media in order to detect variations in electrical resistivity versus time during the release, diffusion and uptake of nutrients. The experiment required a specific geometry for the acquisition of ERT data using the heat-pulse water-content sensor's steel needles as electrodes. ERT data were analyzed using the sensed water contents and deriving pore-water resistivities using Archie's law. This design should provide a more optimal root-zone environment by maintaining a more uniform water content and on-demand supply of water than designs with one particle size at all column heights. The monitoring capability offers an effective means to describe the relationship between root-system performance and plant growth.

  7. Growth Mixture Modeling: Application to Reading Achievement Data from a Large-Scale Assessment

    ERIC Educational Resources Information Center

    Bilir, Mustafa Kuzey; Binici, Salih; Kamata, Akihito

    2008-01-01

    The popularity of growth modeling has increased in psychological and cognitive development research as a means to investigate patterns of changes and differences between observation units over time. Random coefficient modeling, such as multilevel modeling and latent growth curve modeling as a special application of structural equation modeling are…

  8. Modeling user adoption of advanced traveler information systems: a control theoretic approach for optimal endogenous growth

    Microsoft Academic Search

    Hai Yang; Hai-Jun Huang

    2004-01-01

    This study is a subsequent development of the dynamic evolution model of the market penetration of advanced traveler information systems (ATIS) proposed by Yang and Meng [Transport. Res. A 35 (2001) 895]. In previous study we have shown that a benefit-driven, user-optimal ATIS market does not necessarily lead to a socially optimal growth and optimal stationary equilibrium level of market

  9. Optimal Experience and Reading Achievement in Virtual Environments among College Level Developmental Readers

    ERIC Educational Resources Information Center

    Burgess, Melissa L.

    2010-01-01

    In this mixed methods study the potential for developmental readers to experience optimal experience (flow) within the multi-user virtual environment, "Second Life," was examined. In an educational context, "Second Life" provided a space for constructivist learning, socialization, exploration, discovery and creativity. The communicative, social…

  10. Optimizing Pt/TiO2 templates for textured PZT growth and MEMS devices

    NASA Astrophysics Data System (ADS)

    Potrepka, Daniel; Fox, Glenn; Sanchez, Luz; Polcawich, Ronald

    2013-03-01

    Crystallographic texture of lead zirconate titanate (PZT) thin films strongly influences piezoelectric properties used in MEMS applications. Textured growth can be achieved by relying on crystal growth habit and can also be initiated by the use of a seed-layer heteroepitaxial template. Template choice and the process used to form it determine structural quality, ultimately influencing performance and reliability of MEMS PZT devices such as switches, filters, and actuators. This study focuses on how 111-textured PZT is generated by a combination of crystal habit and templating mechanisms that occur in the PZT/bottom-electrode stack. The sequence begins with 0001-textured Ti deposited on thermally grown SiO2 on a Si wafer. The Ti is converted to 100-textured TiO2 (rutile) through thermal oxidation. Then 111-textured Pt can be grown to act as a template for 111-textured PZT. Ti and Pt are deposited by DC magnetron sputtering. TiO2 and Pt film textures and structure were optimized by variation of sputtering deposition times, temperatures and power levels, and post-deposition anneal conditions. The relationship between Ti, TiO2, and Pt texture and their impact on PZT growth will be presented.

  11. Seeding conditions of the halophyte Atriplex patula for optimal growth on a salt impacted site.

    PubMed

    Young, Michelle A; Rancier, Doug G; Roy, Julie L; Lunn, Stuart R; Armstrong, Sarah A; Headley, John V

    2011-08-01

    Salt-impacted soils resulting from oilfield brine spills are increasingly becoming a significant problem in oil-producing areas of Canada such as Alberta and Saskatchewan. The native halophyte Atriplex patula is being considered a potential species for phytoremediation of brine-impacted sites in these hemiboreal climactic zones. The objective of this study was to investigate the optimal seeding conditions under field conditions (with no irrigation) of A. patula for phytoremediation of salt from a brine-impacted site. Atriplex patula was identified in preliminary greenhouse trials to have one of the highest salt accumulations in relation to plant yields. Different seeding methods of A. patula were assessed in an attempt to achieve reproducible growth of this species. While plant yields for A. patula were improved on compacted soil by approximately 30-50%, growth was uneven with regard to density and height. The uneven growth may be due to seed quality and low precipitation during the field season, while improvements in plant yield on compact soil might be due to a lack of competition with other species. PMID:21972494

  12. Optimization of Composite Material System and Lay-up to Achieve Minimum Weight Pressure Vessel

    NASA Astrophysics Data System (ADS)

    Mian, Haris Hameed; Wang, Gang; Dar, Uzair Ahmed; Zhang, Weihong

    2013-10-01

    The use of composite pressure vessels particularly in the aerospace industry is escalating rapidly because of their superiority in directional strength and colossal weight advantage. The present work elucidates the procedure to optimize the lay-up for composite pressure vessel using finite element analysis and calculate the relative weight saving compared with the reference metallic pressure vessel. The determination of proper fiber orientation and laminate thickness is very important to decrease manufacturing difficulties and increase structural efficiency. In the present work different lay-up sequences for laminates including, cross-ply [ 0 m /90 n ] s , angle-ply [ ±?] ns , [ 90/±?] ns and [ 0/±?] ns , are analyzed. The lay-up sequence, orientation and laminate thickness (number of layers) are optimized for three candidate composite materials S-glass/epoxy, Kevlar/epoxy and Carbon/epoxy. Finite element analysis of composite pressure vessel is performed by using commercial finite element code ANSYS and utilizing the capabilities of ANSYS Parametric Design Language and Design Optimization module to automate the process of optimization. For verification, a code is developed in MATLAB based on classical lamination theory; incorporating Tsai-Wu failure criterion for first-ply failure (FPF). The results of the MATLAB code shows its effectiveness in theoretical prediction of first-ply failure strengths of laminated composite pressure vessels and close agreement with the FEA results. The optimization results shows that for all the composite material systems considered, the angle-ply [ ±?] ns is the optimum lay-up. For given fixed ply thickness the total thickness of laminate is obtained resulting in factor of safety slightly higher than two. Both Carbon/epoxy and Kevlar/Epoxy resulted in approximately same laminate thickness and considerable percentage of weight saving, but S-glass/epoxy resulted in weight increment.

  13. Modeling urban growth by the use of a multiobjective optimization approach: environmental and economic issues for the Yangtze watershed, China.

    PubMed

    Zhang, Wenting; Wang, Haijun; Han, Fengxiang; Gao, Juan; Nguyen, Thuminh; Chen, Yarong; Huang, Bo; Zhan, F Benjamin; Zhou, Lequn; Hong, Song

    2014-11-01

    Urban growth is an unavoidable process caused by economic development and population growth. Traditional urban growth models represent the future urban growth pattern by repeating the historical urban growth regulations, which can lead to a lot of environmental problems. The Yangtze watershed is the largest and the most prosperous economic area in China, and it has been suffering from rapid urban growth from the 1970s. With the built-up area increasing from 23,238 to 31,054 km(2) during the period from 1980 to 2005, the watershed has suffered from serious nonpoint source (NPS) pollution problems, which have been mainly caused by the rapid urban growth. To protect the environment and at the same time maintain the economic development, a multiobjective optimization (MOP) is proposed to tradeoff the multiple objectives during the urban growth process of the Yangtze watershed. In particular, the four objectives of minimization of NPS pollution, maximization of GDP value, minimization of the spatial incompatibility between the land uses, and minimization of the cost of land-use change are considered by the MOP approach. Conventionally, a genetic algorithm (GA) is employed to search the Pareto solution set. In our MOP approach, a two-dimensional GA, rather than the traditional one-dimensional GA, is employed to assist with the search for the spatial optimization solution, where the land-use cells in the two-dimensional space act as genes in the GA. Furthermore, to confirm the superiority of the MOP approach over the traditional prediction approaches, a widely used urban growth prediction model, cellular automata (CA), is also carried out to allow a comparison with the Pareto solution of MOP. The results indicate that the MOP approach can make a tradeoff between the multiple objectives and can achieve an optimal urban growth pattern for Yangtze watershed, while the CA prediction model just represents the historical urban growth pattern as the future growth pattern. Moreover, according to the spatial clustering index, the urban growth pattern predicted through MOP is more reasonable. In summary, the proposed model provides a set of Pareto urban growth solutions, which compromise environmental and economic issues for the Yangtze watershed. PMID:24994100

  14. J. AMER. SOC. HORT. SCI. 126(5):638643. 2001. Optimization of Transpiration and Potential Growth

    E-print Network

    Lieth, J. Heinrich

    J. AMER. SOC. HORT. SCI. 126(5):638­643. 2001. Optimization of Transpiration and Potential Growth, microcalorimetry, potential growth, respiration rate, Rosa �hybrida, transpiration ABSTRACT. Physical transpiration rate, stomatal conductance, and specific growth rate of very young leaflets of `Kardinal' rose

  15. Quantitative analysis in the characterization and optimization of protein crystal growth.

    PubMed

    Carter, C W; Yin, Y

    1994-07-01

    Protein crystal growth often depends on the combination of many different factors. Some affect protein solubility directly; others may act indirectly by causing conformational changes. Systematic characterization of these factors can be important for generating good crystals. It can also provide useful insight into the biochemical behavior of the protein being crystallized. Here we focus on statistical methods to achieve these two objectives. (1) Characterization of a protein system by analyzing patterns of crystal polymorphism under different levels of biochemical parameters, such as ligands and pH. Tests of the reproducibility of crystal growth experiments indicate that quantitative scales of crystal quality can be statistically significant. Analysis of variance for a replicated, full-factorial design in which four factors were tested at two levels has been used to demonstrate highly significant, biochemically relevant, two-factor interactions strongly implicating pH and ligand-dependent conformational changes. (2) Optimization of crystal growth via response-surface methods. 'Minimum predicted variance' designs provide for efficient response-surface experiments aimed at constructing quadratic models in several dimensions. We have used such models to improve crystal size and quality significantly for three forms of Bacillus stearothermophilus tryptophanyl-tRNA synthetase. In one case we can now avoid having to increase the size by repeated seeding, a difficult procedure that also produces unwanted growth of satellite crystals. Graphs of two-dimensional level surfaces reveal a number of ridges, where the same result is obtained for many combinations of the factors usually varied when trying to improve crystals. An important inference is that it may be better to sample simultaneously for the effects of protein concentration and supersaturation. For a system involving only one crystallizing agent, supersaturation can be approximated as the product of protein and precipitant concentrations. Use of this search direction significantly improves the performance of response-surface experiments. Advantages of growing crystals at stationary points of their response surfaces include better crystals and higher reproducibility, since crystal growth at stationary points is insulated from the deleterious effects of experimental fluctuations. This arises because the derivatives of the response are by definition zero with respect to the experimental variables. Quantitative analysis of appropriately designed crystal growth experiments can thus be a powerful way to characterize complex and interacting biochemical dependencies in macromolecular systems and optimize parameters important to the crystallography. PMID:15299421

  16. Social Spending, Human Capital, and Growth in Developing Countries: Implications for Achieving the MDGs

    Microsoft Academic Search

    Emanuele Baldacci; Benedict J. Clements; Sanjeev Gupta

    2004-01-01

    Using panel data from 120 developing countries from 1975 to 2000, this paper explores the direct and indirect channels linking social spending, human capital, and growth in a system of equations. The paper finds that both education and health spending have a positive and significant direct impact on the accumulation of education and health capital, and thus can lead to

  17. A Latent Growth Curve Analysis of Reading Achievement for an At-Risk Population

    ERIC Educational Resources Information Center

    Beecher, Constance C.

    2011-01-01

    The development of reading skills from age seven until age 19 was investigated for children who were referred for special education preschool intervention using latent growth curve analysis (n=206). Approximately one-third of the study sample did not require special education services after preschool, providing a natural comparison group. Reading…

  18. DASEES: A Tripartite Decision Analysis Framework to Achieve Sustainable Environment, Economy & Society Growth and Management Goals

    EPA Science Inventory

    Many of Societies management and growth decisions are often made without a balanced consideration of pertinent factors from environmental, economic and societal perspectives. All three of these areas are key players in many of the decisions facing societies as they strive to ope...

  19. Does Growth Rate in Oral Reading Fluency Matter in Predicting Reading Comprehension Achievement?

    ERIC Educational Resources Information Center

    Kim, Young-Suk; Petscher, Yaacov; Schatschneider, Christopher; Foorman, Barbara

    2010-01-01

    In this study, we examined the relationship of growth trajectories of oral reading fluency, vocabulary, phonological awareness, letter-naming fluency, and nonsense word reading fluency from 1st grade to 3rd grade with reading comprehension in 1st, 2nd, and 3rd grades. Data from 12,536 children who were followed from kindergarten to 3rd grade…

  20. Birth Weight, Math and Reading Achievement Growth: A Multilevel between-Sibling, between-Families Approach

    ERIC Educational Resources Information Center

    Goosby, Bridget J.; Cheadle, Jacob E.

    2009-01-01

    We used multilevel covariance structure analysis to study the relationship between birth weight, family context and youth math and reading comprehension growth from approximately ages 5 through 14 within and between families. Using data from the National Longitudinal Survey of Youth Child Sample, we examined the relationship between birth weight…

  1. Epstein-Barr virus exploits intrinsic B-lymphocyte transcription programs to achieve immortal cell growth

    E-print Network

    Chen, Yiling

    Epstein-Barr virus exploits intrinsic B-lymphocyte transcription programs to achieve immortal cell Contributed by Elliott Kieff, June 3, 2011 (sent for review April 15, 2011) Epstein-Barr virus nuclear antigen likely supports antigen-induced proliferation. leukemia | lymphoma | Notch | development Epstein Barr

  2. Vaughn Elementary's Innovative Teacher Evaluation System: Are Teacher Evaluation Scores Related to Growth in Student Achievement?

    ERIC Educational Resources Information Center

    Gallagher, H. Alix

    2004-01-01

    In this study, I examined the validity of a performance-based, subject-specific teacher evaluation system by analyzing the relationship between teacher evaluation scores and student achievement. From a policy perspective, establishing validity was important because it is embedded in a knowledge-and skills-based pay system, which attached high…

  3. Perceived Social Support and Academic Achievement: Cross-Lagged Panel and Bivariate Growth Curve Analyses

    ERIC Educational Resources Information Center

    Mackinnon, Sean P.

    2012-01-01

    As students transition to post-secondary education, they experience considerable stress and declines in academic performance. Perceived social support is thought to improve academic achievement by reducing stress. Longitudinal designs with three or more waves are needed in this area because they permit stronger causal inferences and help…

  4. Target size and optimal life history when individual growth and energy budget are stochastic.

    PubMed

    Filin, Ido

    2010-05-21

    I extend my previous work on life history optimization when body mass is divided into reserves and structure components. Two important innovations are: (1) effect of finite target size on optimal structural growth; (2) incorporating reproduction in the optimization objective. I derive optimal growth trajectories and life histories, given that the individual is subject to both starvation mortality and exogenous hazards (e.g., predation). Because of overhead costs in building structural mass, it is optimal to stop structural growth close to the target size, and to proceed only by accumulating reserves. Higher overhead costs cause earlier cessation of structural growth and smaller final structures. Semelparous reproduction also promotes early cessation of structural growth, compared to when only survival to target size is maximized. In contrast, iteroparous reproduction can prolong structural growth, resulting in larger final structures than in either the survival or the semelparous scenarios. Increasing the noise in individual growth lowers final structural mass at small target sizes, but the effect is reversed for large target sizes. My results provide predictions for comparative studies. I outline important consequences of my results to additional important evolutionary questions: evolution of sexual dimorphism, optimization of clutch size and evolution of progeny and adult sizes. PMID:20184902

  5. Sixty-four MDCT achieves higher contrast in pancreas with optimization of scan time delay

    PubMed Central

    Stuber, Tina; Brambs, Hans-Jürgen; Freund, Wolfgang; Juchems, Markus S

    2012-01-01

    AIM: To compare different multidetector computed tomography (MDCT) protocols to optimize pancreatic contrast enhancement. METHODS: Forty consecutive patients underwent contrast-enhanced biphasic MDCT (arterial and portal-venous phase) using a 64-slice MDCT. In 20 patients, the scan protocol was adapted from a previously used 40-channel MDCT scanner with arterial phase scanning initiated 11.1 s after a threshold of 150 HU was reached in the descending aorta, using automatic bolus tracking (Protocol 1). The 11.1-s delay was changed to 15 s in the other 20 patients to reflect the shorter scanning times on the 64-channel MDCT compared to the previous 40-channel system (Protocol 2). HU values were measured in the head and tail of the pancreas in the arterial and portal-venous phase. RESULTS: Using an 11.1-s delay, 74.2 HU (head) were measured on average in the arterial phase and 111.2 HU (head) were measured using a 15-s delay (P < 0.0001). For the pancreatic tail, the average attenuation level was 76.73 HU (11.1 s) and 99.89 HU (15 s) respectively (P = 0.0002). HU values were also significantly higher in the portal-venous phase [pancreatic head: 70.5 HU (11.1 s) vs 84.0 HU (15 s) (P = 0.0014); pancreatic tail: 67.45 HU (11.1 s) and 77.18 HU (15 s) using Protocol 2 (P = 0.0071)]. CONCLUSION: Sixty-four MDCT may yield a higher contrast in pancreatic study with (appropriate) optimization of scan delay time. PMID:22900134

  6. Optimization of growth media components for polyhydroxyalkanoate (PHA) production from organic acids by Ralstonia eutropha

    E-print Network

    Yang, Yung-Hun

    We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid ...

  7. Optimal control on bladder cancer growth model with BCG immunotherapy and chemotherapy

    NASA Astrophysics Data System (ADS)

    Dewi, C.; Trisilowati

    2015-03-01

    In this paper, an optimal control model of the growth of bladder cancer with BCG (Basil Calmate Guerin) immunotherapy and chemotherapy is discussed. The purpose of this optimal control is to determine the number of BCG vaccine and drug should be given during treatment such that the growth of bladder cancer cells can be suppressed. Optimal control is obtained by applying Pontryagin principle. Furthermore, the optimal control problem is solved numerically using Forward-Backward Sweep method. Numerical simulations show the effectiveness of the vaccine and drug in controlling the growth of cancer cells. Hence, it can reduce the number of cancer cells that is not infected with BCG as well as minimize the cost of the treatment.

  8. Optimization of the Crystal Surface Temperature Distribution in the Single-Crystal Growth Process by the Czochralski Method

    Microsoft Academic Search

    Ja Hoon Jeong

    2002-01-01

    The optimization of the crystal surface temperature distribution is performed for single-crystal growth in the Czochralski process. In the optimization problem, we seek an optimal solution in the sense that the index of crystalline defects is minimized while the single-crystal growth rate is maximized. In the objective function, the von Mises stress is considered a driving force that induces crystalline

  9. Optimal Ablation Volumes Are Achieved at Submaximal Power Settings in a 2.45-GHz Microwave Ablation System.

    PubMed

    Niemeyer, David J; Simo, Kerri A; McMillan, Matthew T; Seshadri, Ramanathan M; Hanna, Erin M; Swet, Jacob H; Swan, Ryan Z; Sindram, David; Martinie, John B; McKillop, Iain H; Iannitti, David A

    2015-02-01

    Introduction. Local ablative therapies, including microwave ablation (MWA), are common treatment modalities for in situ tumor destruction. Currently, 2.45-GHz ablation systems are gaining prominence because of the shorter application times required. The aims of this study were to determine optimal power and time to ablation volume (AbV) ratios for a new 1.8-mm-2.45-GHz antenna using ex vivo tissue models. Methods. The 1.8-mm-2.45-GHz Accu2i MWA system was employed to perform ablations in bovine liver, porcine muscle, and porcine kidney ex vivo. Whole tissues were prewarmed (35°C) and multiple ablations performed at power settings of 60 to 180 W for 2- to 6-minute time intervals. Postablation, tissues were dissected, AbVs calculated, and correlations to power and time settings made. Results. Significant increases in AbV were measured between each of the time points for a constant power setting in all 3 tissues. Increasing power settings led to significant increases in AbV at power settings ?140 W. However, no significant increase in AbV was obtained at power settings >140 W. Conclusions. Optimal efficiency for MWA using a new 1.8-mm-2.45-GHz system is achieved at settings of ?140 W for 6 minutes in a range of ex vivo tissue and no additional benefit occurs by increasing the power setting to 180 W in these tissues. PMID:24899579

  10. Enhanced minority carrier lifetimes in GaAs/AlGaAs core-shell nanowires through shell growth optimization.

    PubMed

    Jiang, N; Gao, Q; Parkinson, P; Wong-Leung, J; Mokkapati, S; Breuer, S; Tan, H H; Zheng, C L; Etheridge, J; Jagadish, C

    2013-11-13

    The effects of AlGaAs shell thickness and growth time on the minority carrier lifetime in the GaAs core of GaAs/AlGaAs core-shell nanowires grown by metal-organic chemical vapor deposition are investigated. The carrier lifetime increases with increasing AlGaAs shell thickness up to a certain value as a result of reducing tunneling probability of carriers through the AlGaAs shell, beyond which the carrier lifetime reduces due to the diffusion of Ga-Al and/or impurities across the GaAs/AlGaAs heterointerface. Interdiffusion at the heterointerface is observed directly using high-angle annular dark field scanning transmission electron microscopy. We achieve room temperature minority carrier lifetimes of 1.9 ns by optimizing the shell growth with the intention of reducing the effect of interdiffusion. PMID:24127827

  11. Thermal Optimization of Growth and Quality in Protein Crystals

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.

    1996-01-01

    Experimental evidence suggests that larger and higher quality crystals can be attained in the microgravity of space; however, the effect of growth rate on protein crystal quality is not well documented. This research is the first step towards providing strategies to grow crystals under constant rates of growth. Controlling growth rates at a constant value allows for direct one-to-one comparison of results obtained in microgravity and on earth. The overall goal of the project was to control supersaturation at a constant value during protein crystal growth by varying temperature in a predetermined manner. Applying appropriate theory requires knowledge of specific physicochemical properties of the protein solution including the effect of supersaturation on growth rates and the effect of temperature on protein solubility. Such measurements typically require gram quantities of protein and many months of data acquisition. A second goal of the project applied microcalorimetry for the rapid determination of these physicochemical properties using a minimum amount of protein. These two goals were successfully implemented on hen egg-white lysozyme. Results of these studies are described in the attached reprints.

  12. Achieving pH control in microalgal cultures through fed-batch addition of stoichiometrically-balanced growth media

    PubMed Central

    2013-01-01

    Background Lack of accounting for proton uptake and secretion has confounded interpretation of the stoichiometry of photosynthetic growth of algae. This is also problematic for achieving growth of microalgae to high cell concentrations which is necessary to improve productivity and the economic feasibility of commercial-scale chemical production systems. Since microalgae are capable of consuming both nitrate and ammonium, this represents an opportunity to balance culture pH based on a nitrogen feeding strategy that does not utilize gas-phase CO2 buffering. Stoichiometry suggests that approximately 36 weight%N-NH4+ (balance nitrogen as NO3-) would minimize the proton imbalance and permit high-density photoautotrophic growth as it does in higher plant tissue culture. However, algal media almost exclusively utilize nitrate, and ammonium is often viewed as ‘toxic’ to algae. Results The microalgae Chlorella vulgaris and Chlamydomonas reinhardtii exclusively utilize ammonium when both ammonium and nitrate are provided during growth on excess CO2. The resulting proton imbalance from preferential ammonium utilization causes the pH to drop too low to sustain further growth when ammonium was only 9% of the total nitrogen (0.027 gN-NH4+/L). However, providing smaller amounts of ammonium sequentially in the presence of nitrate maintained the pH of a Chlorella vulgaris culture for improved growth on 0.3 gN/L to 5 gDW/L under 5% CO2 gas-phase supplementation. Bioreactor pH dynamics are shown to be predictable based on simple nitrogen assimilation as long as there is sufficient CO2 availability. Conclusions This work provides both a media formulation and a feeding strategy with a focus on nitrogen metabolism and regulation to support high-density algal culture without buffering. The instability in culture pH that is observed in microalgal cultures in the absence of buffers can be overcome through alternating utilization of ammonium and nitrate. Despite the highly regulated array of nitrogen transporters, providing a nitrogen source with a balanced degree of reduction minimizes pH fluctuations. Understanding and accommodating the behavior of nitrogen utilization in microalgae is key to avoiding ‘culture crash’ and reliance on gas phase CO2 buffering, which becomes both ineffective and cost-prohibitive for commercial-scale algal culture. PMID:23651806

  13. Population growth and the benefits from optimally priced externalities.

    PubMed

    Clarke, H R; Ng Y-k

    1995-06-01

    "In this article we show that, considering only economic effects, even if population growth, by natural increase or immigration, increases congestion, pollution, and other forms of external costs, that provided pre-existing citizens own the resources giving rise to the externalities, and provided they efficiently price usage of such, that existing citizens must, in net average terms, be better off with population growth than without it. In simple terms the increased revenues they gain from efficient pricing at increased demand levels will be strictly greater than the monetary value of the increased external costs together with the higher tax costs they incur as consumers of the resources." PMID:12347617

  14. Understanding the development of roots exposed to contaminants and the potential of plant-associated bacteria for optimization of growth

    PubMed Central

    Remans, Tony; Thijs, Sofie; Truyens, Sascha; Weyens, Nele; Schellingen, Kerim; Keunen, Els; Gielen, Heidi; Cuypers, Ann; Vangronsveld, Jaco

    2012-01-01

    Background and Scope Plant responses to the toxic effects of soil contaminants, such as excess metals or organic substances, have been studied mainly at physiological, biochemical and molecular levels, but the influence on root system architecture has received little attention. Nevertheless, the precise position, morphology and extent of roots can influence contaminant uptake. Here, data are discussed that aim to increase the molecular and ecological understanding of the influence of contaminants on root system architecture. Furthermore, the potential of plant-associated bacteria to influence root growth by their growth-promoting and stress-relieving capacities is explored. Methods Root growth parameters of Arabidopsis thaliana seedlings grown in vertical agar plates are quantified. Mutants are used in a reverse genetics approach to identify molecular components underlying quantitative changes in root architecture after exposure to excess cadmium, copper or zinc. Plant-associated bacteria are isolated from contaminated environments, genotypically and phenotypically characterized, and used to test plant root growth improvement in the presence of contaminants. Key Results The molecular determinants of primary root growth inhibition and effects on lateral root density by cadmium were identified. A vertical split-root system revealed local effects of cadmium and copper on root development. However, systemic effects of zinc exposure on root growth reduced both the avoidance of contaminated areas and colonization of non-contaminated areas. The potential for growth promotion and contaminant degradation of plant-associated bacteria was demonstrated by improved root growth of inoculated plants exposed to 2,4-di-nitro-toluene (DNT) or cadmium. Conclusions Knowledge concerning the specific influence of different contaminants on root system architecture and the molecular mechanisms by which this is achieved can be combined with the exploitation of plant-associated bacteria to influence root development and increase plant stress tolerance, which should lead to more optimal root systems for application in phytoremediation or safer biomass production. PMID:22634257

  15. Optimization of growth media components for polyhydroxyalkanoate (PHA) production from organic acids by Ralstonia eutropha.

    PubMed

    Yang, Yung-Hun; Brigham, Christopher J; Budde, Charles F; Boccazzi, Paolo; Willis, Laura B; Hassan, Mohd Ali; Yusof, Zainal Abidin Mohd; Rha, ChoKyun; Sinskey, Anthony J

    2010-08-01

    We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid for robust cell growth and high PHA production. The 3-hydroxyvalerate content in the resulting PHA depended on the proportion of propionate initially present in the growth medium. The proportion of acetate dramatically affected the final pH of the growth medium. A model was constructed using our data that predicts the effects of these acids, individually and in combination, on cell dry weight (CDW), PHA content (%CDW), PHA production, 3HV in the polymer, and final culture pH. Cell growth and PHA production improved approximately 1.5-fold over initial conditions when the proportion of butyrate was increased. Optimization of the phosphate buffer content in medium containing higher amounts of butyrate improved cell growth and PHA production more than 4-fold. The validated organic acid mixture analysis model can be used to optimize R. eutropha culture conditions, in order to meet targets for PHA production and/or polymer HV content. By modifying the growth medium made from treated industrial waste, such as palm oil mill effluent, more PHA can be produced. PMID:20535466

  16. Growth Optimal Portfolio Selection Under Proportional Transaction Costs with Obligatory Diversification

    SciTech Connect

    Duncan, T., E-mail: duncan@math.ku.edu; Pasik Duncan, B., E-mail: bozenna@math.ku.ed [University of Kansas, Department of Mathematics (United States); Stettner, L., E-mail: stettner@impan.gov.p [Institute of Mathematics Polish Acad. Sci. (Poland)

    2011-02-15

    A continuous time long run growth optimal or optimal logarithmic utility portfolio with proportional transaction costs consisting of a fixed proportional cost and a cost proportional to the volume of transaction is considered. The asset prices are modeled as exponent of diffusion with jumps whose parameters depend on a finite state Markov process of economic factors. An obligatory portfolio diversification is introduced, accordingly to which it is required to invest at least a fixed small portion of our wealth in each asset.

  17. In vitro culture of Safflower L. cv. Bhima: initiation, growth optimization and organogenesis

    Microsoft Academic Search

    T. D. Nikam; M. G. Shitole

    1998-01-01

    Callus induction and in vitro plantlet regeneration systems for safflower (Carthamus tinctorius L.) cv. Bhima using root,\\u000a hypocotyl, cotyledon and leaf explants were optimized by studying the influence on organogenesis of seedling age, media factors,\\u000a growth regulators and excision orientation. Supplementation of the medium with an auxin: cytokinin ratio < 1 enhanced the\\u000a growth rate of callus cultures; however, for

  18. Layered Plant-Growth Media for Optimizing Gaseous, Liquid and Nutrient Requirements: Modeling, Design and Monitoring

    Microsoft Academic Search

    R. Heinse; S. B. Jones; G. Bingham; B. Bugbee

    2006-01-01

    Rigorous management of restricted root zones utilizing coarse-textured porous media greatly benefits from optimizing the gas-water balance within plant-growth media. Geophysical techniques can help to quantify root- zone parameters like water content, air-filled porosity, temperature and nutrient concentration to better address the root systems performance. The efficiency of plant growth amid high root densities and limited volumes is critically linked

  19. Posttraumatic Growth and Optimism in Health-Related Trauma: A Systematic Review

    Microsoft Academic Search

    Lucy Bostock; Alia I. Sheikh; Stephen Barton

    2009-01-01

    Posttraumatic growth (PTG) research is an emerging area of empirical study, especially within the field of clinical health\\u000a psychology. Much of the research in this area has thus far focused on determining the correlates and predictors of PTG. This\\u000a systematic review aimed to evaluate the association between posttraumatic growth and dispositional optimism, specifically\\u000a in relation to health traumas. Empirical studies

  20. Resonance effects on the dynamics of dense granular beds: achieving optimal energy transfer in vibrated granular systems

    NASA Astrophysics Data System (ADS)

    Windows-Yule, C. R. K.; Rosato, A. D.; Thornton, A. R.; Parker, D. J.

    2015-02-01

    Using a combination of experimental techniques and discrete particle method simulations, we investigate the resonant behaviour of a dense, vibrated granular system. We demonstrate that a bed of particles driven by a vibrating plate may exhibit marked differences in its internal energy dependent on the specific frequency at which it is driven, even if the energy corresponding to the oscillations driving the system is held constant and the acceleration provided by the base remains consistently significantly higher than the gravitational acceleration, g. We show that these differences in the efficiency of energy transfer to the granular system can be explained by the existence of resonances between the bed’s bulk motion and that of the oscillating plate driving the system. We systematically study the dependency of the observed resonant behaviour on the system’s main, controllable parameters and, based on the results obtained, propose a simple empirical model capable of determining, for a given system, the points in parameter space for which optimal energy transfer may be achieved.

  1. Tumor Growth Rate Determines the Timing of Optimal Chronomodulated Treatment Schedules

    E-print Network

    Paris-Sud XI, Université de

    Tumor Growth Rate Determines the Timing of Optimal Chronomodulated Treatment Schedules Samuel the best timing of treatments. However, the influence of variations in tumor kinetics has not been kinetics of the tumor. Then, we developed a theoretical analysis of treatment outcome (TATO) to relate

  2. Optimization of diamond nucleation and growth using MW-PACVD method

    Microsoft Academic Search

    H. Buchkremer-Hermanns; H. Ren; H. Wei?

    1996-01-01

    An investigation was initiated to find the optimum process parameters which favour diamond nucleation and subsequent growth. The parameters examined were the reactor pressure, substrate temperature, gas flow rate and methane concentration; each factor was varied gradually in selected ranges. The experiments were carried out according to an optimization method which was developed from orthogonal designs. Using this method the

  3. OPTIMAL GROWTH IN A TWO-SECTOR RSS MODEL WITHOUT DISCOUNTING: A GEOMETRIC INVESTIGATION

    Microsoft Academic Search

    M. ALI KHAN; TAPAN MITRA

    2007-01-01

    This essay reports results on optimal growth in a two-sector model with fixed coefficients, irreversible investment and no discounting. Under normalization, the model can be represented by two real numbers, but despite its deceptive simplicity, it admits rich transition dynamics and apparent pathologies that seem to have been missed in earlier work. From a methodological point of view, and in

  4. Optimized growth and plant regeneration for callus of Lilium longiflorum cv. Nellie White

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rates of growth and regeneration were compared for compact callus, friable callus, and suspension cells of Lilium longiflorum cv. Nellie White to determine the optimal culture conditions. The fresh weight was higher for compact callus induced from bulb scales cultured on Murashige and Skoog’s m...

  5. Optimal Growth of Antarctic Circumpolar Waves CHRISTOPHER M. AIKEN AND MATTHEW H. ENGLAND

    E-print Network

    England, Matthew

    Optimal Growth of Antarctic Circumpolar Waves CHRISTOPHER M. AIKEN AND MATTHEW H. ENGLAND Centre for Environmental Modelling and Prediction, School of Mathematics, University of New South Wales, Sydney, New South surface temperature obeying a simple heat balance. Eigenanalysis of the system reveals modes

  6. Optimization of media and fermentation conditions for the growth of Lactobacillus sakei

    Microsoft Academic Search

    T. LECHIANCOLE; A. RICCIARDI; E. PARENTE

    Factorial experiments, empirical model building and response surface analysis were used to optimize media composition and fermentation conditions for the propagation of Lactobacillus sakei, a species used as a starter in the manufacture of fermented sausages. Yeast extract, Lab-Lemco and, to a minor extent, Bacteriological peptone were found to be good sources of peptides and growth factors for L. sakei,

  7. Optimizing Growth Hormone Replacement Therapy by Dose Titration in Hypopituitary Adults

    Microsoft Academic Search

    W. M. Drake; D. COYTE; C. CAMACHO-HUBNER; N. M. JIVANJI; G. KALTSAS; D. F. WOOD; P. J. TRAINER; A. B. GROSSMAN; G. M. BESSER; J. P. MONSON

    1998-01-01

    Although growth hormone (GH) replacement therapy is increas- ingly utilized in the management of adult hypopituitary patients, optimum dosing schedules are poorly defined. The use of weight-based or surface area-based dosing may result in overtreatment, and indi- vidual variation in susceptibility on the basis of gender and other factors is now being recognized. To optimize GH replacement and to explore

  8. Dynamic optimization of hybridoma growth in a fed-batch bioreactor.

    PubMed

    Dhir, S; Morrow, K J; Rhinehart, R R; Wiesner, T

    2000-01-20

    This study addressed the problem of maximizing cell mass and monoclonal antibody production from a fed-batch hybridoma cell culture. We hypothesized that inaccuracies in the process model limited the mathematical optimization. On the basis of shaker flask data, we established a simple phenomenological model with cell mass and lactate production as the controlled variables. We then formulated an optimal control algorithm, which calculated the process-model mismatch at each sampling time, updated the model parameters, and re-optimized the substrate concentrations dynamically throughout the time course of the batch. Manipulated variables were feed rates of glucose and glutamine. Dynamic parameter adjustment was done using a fuzzy logic technique, while a heuristic random optimizer (HRO) optimized the feed rates. The parameters selected for updating were specific growth rate and the yield coefficient of lactate from glucose. These were chosen by a sensitivity analysis. The cell mass produced using dynamic optimization was compared to the cell mass produced for an unoptimized case, and for a one-time optimization at the beginning of the batch. Substantial improvements in reactor productivity resulted from dynamic re-optimization and parameter adjustment. We demonstrated first that a single offline optimization of substrate concentration at the start of the batch significantly increased the yield of cell mass by 27% over an unoptimized fermentation. Periodic optimization online increased yield of cell mass per batch by 44% over the single offline optimization. Concomitantly, the yield of monoclonal antibody increased by 31% over the off-line optimization case. For batch and fed-batch processes, this appears to be a suitable arrangement to account for inaccuracies in process models. This suggests that implementation of advanced yet inexpensive techniques can improve performance of fed-batch reactors employed in hybridoma cell culture. PMID:10592517

  9. A Longitudinal Study on State Mathematics and Reading Assessments: Comparisons of Growth Models on Students' Achievement Scores

    ERIC Educational Resources Information Center

    Chiu, Pui Chi

    2012-01-01

    This study examines student growth on mathematics and reading assessments across academic years (Spring 2006 through Spring 2009) using three different growth models: hierarchical linear model (HLM), value-added model (VAM), and student growth percentile model (SGP). Comparisons across these three growth models were conducted to investigate the…

  10. Use of allopurinol with low-dose 6-mercaptopurine in inflammatory bowel disease to achieve optimal active metabolite levels: A review of four cases and the literature

    PubMed Central

    Witte, Todd N; Ginsberg, Allen L

    2008-01-01

    BACKGROUND: At least one-third of patients with inflammatory bowel disease do not respond or are intolerant to therapy with 6-mercaptopurine (6-MP). A subgroup fails to attain optimal levels of 6-thioguanine nucleotide (6-TGN) and instead shunts to 6-methylmercaptopurine nucleotide (6-MMPN). PATIENTS AND METHODS: A retrospective chart review was conducted, and four patients are described who had been previously unable to achieve optimal 6-TGN metabolite levels until allopurinol was added to their treatment. RESULTS: All four patients achieved optimal 6-TGN levels and undetectable 6-MMPN with a mean 6-MP dose of 0.49 mg/kg. Three achieved steroid-free clinical remission. Two of those three patients had normalization of liver enzymes; one patient had baseline normal liver enzymes despite an initial 6-MMPN level of 27,369 pmol/8×108 red blood cells. Two patients experienced reversible leukopenia. CONCLUSIONS: Combination allopurinol and low-dose 6-MP is an effective means to achieve optimal metabolite levels and steroid-free clinical remission in previously refractory patients. Caution is advised. PMID:18299738

  11. The optimization of the growth on (111) gallium arsenide and (111) indium phosphide substrates by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Yeo, Hock Huat

    Growing on (111) oriented substrate has been long attracted much attentions due to the presence of piezoelectric field when the material is under strain. However, growing on this orientation still poses a great challenge to crystal grower due to the tendency of forming pyramidal facets along the <110> directions. This dissertation covers the optimization of the growth on (111) GaAs and (111) InP substrates using molecular beam epitaxy. The enhancement of the material performance due to the piezoelectric effects was also investigated in this dissertation. Growing on (111)A surface is very difficult due to the fact that the surface is terminated with group III atoms. On this surface, Si can either occupy the group III site, becomes a donor, or the group V site, becomes an acceptor, depending on the growth condition. Also, the group III terminated surface makes the epi-layer grown on (111)A substrates metal-rich under most of the growth conditions. Therefore, a high quality material is hard to obtain on (111)A surface. Whereas, growing on (111)B surface, Si always acts as a donor. High quality epi-layer can be achieved by employing high growth temperature, low V/III ratio and misoriented substrate. High quality AlGaAs/GaAs heterostructure has been grown on (111)B GaAs substrates. Two-dimensional electron gas (2DEG) Hall mobility of 7,200 cm 2/Vs with sheet density of 7.7 x 1011 cm -2 with a 134 A spacer layer at room temperature, and 90,000 cm2/Vs with sheet density of 6.2 x 1011 cm-2 at 77K have been achieved on (111)B GaAs. Excellent material has also been grown on (111)B InP. InAlAs/InGaAs heterostructure grown on (111)B InP gave a room temperature 2DEG Hall mobility of 11,200 cm 2/VS with sheet density of 3.0 x 1012 cm -2 with a 40 A spacer layer. At 77K, the 2DEG Hall mobility was 42,800 cm2/Vs with sheet density of 2.3 x 1012 cm-2. This heterostructure showed a 30% enhancement in 2DEG sheet density due to the piezoelectric effects. Excellent material has been grown on (111) surface using molecular beam epitaxy. This dissertation covers the optimal growth condition of (111)B GaAs and (111)B InP. With electrostatic analysis plus semiempirical approach, a simple equation for estimating the 2DEG sheet density is also presented in this dissertation.

  12. Branched-Chain Amino Acid Biosynthesis Is Essential for Optimal Growth of Streptococcus thermophilus in Milk

    PubMed Central

    Garault, P.; Letort, C.; Juillard, V.; Monnet, V.

    2000-01-01

    Lactic acid bacteria are nutritionally demanding bacteria which need, among other things, amino acids for optimal growth. We identified the branched-chain amino acid (BCAA) biosynthesis pathway as an essential pathway for optimal growth of Streptococcus thermophilus in milk. Through random insertional mutagenesis, we isolated and characterized two mutants for which growth in milk is affected as a consequence of ilvB and ilvC gene interruptions. This situation demonstrates that the BCAA biosynthesis pathway is active in S. thermophilus. BCAA biosynthesis is necessary but not sufficient for optimal growth of S. thermophilus and is subject to retro-inhibition processes. The specificity of the BCAA biosynthesis pathway in S. thermophilus lies in the independent transcription of the ilvC gene encoding a keto acid reductoisomerase acting on acetolactate at the junction of the BCAA and acetoin biosynthesis pathways. The possible advantages for S. thermophilus of keeping this biosynthesis pathway active could be linked either to adaptation of the organism to milk, which is different than that of other dairy bacteria, or to the role of the pathway in maintaining the internal pH. PMID:11097879

  13. Optimization of photobioreactor growth conditions for a cyanobacterium expressing mosquitocidal Bacillus thuringiensis Cry proteins.

    PubMed

    Ketseoglou, Irene; Bouwer, Gustav

    2013-08-10

    An Anabaena strain (PCC 7120#11) that was genetically engineered to express Bacillus thuringiensis subsp. israelensis cry genes has shown good larvicidal activity against Anopheles arabiensis, a major vector of malaria in Africa. Response surface methodology was used to evaluate the relationship between key growth factors and the volumetric productivity of PCC 7120#11 in an indoor, flat-plate photobioreactor. The interaction of input CO? concentration and airflow rate had a statistically significant effect on the volumetric productivity of PCC 7120#11, as did the interaction of airflow rate and photosynthetic photon flux density. Model-based numerical optimization indicated that the optimal factor level combination for maximizing PCC 7120#11 volumetric productivity was a photosynthetic photon flux density of 154 ?mol m?² s?¹ and air enriched with 3.18% (v/v) CO? supplied at a flow rate of 1.02 vessel volumes per minute. At the levels evaluated in the study, none of the growth factors had a significant effect on the median lethal concentration of PCC 7120#11 against An. arabiensis larvae. This finding is important because loss of mosquitocidal activity under growth conditions that maximize volumetric productivity would impact on the feasibility of using PCC 7120#11 in malaria vector control programs. The study showed the usefulness of response surface methodology for determination of the optimal growth conditions for a cyanobacterium that is genetically engineered to have larvicidal activity against malaria vectors. PMID:23732832

  14. Super-optimal CO2 reduces seed yield but not vegetative growth in wheat

    NASA Technical Reports Server (NTRS)

    Grotenhuis, T. P.; Bugbee, B.

    1997-01-01

    Although terrestrial atmospheric CO2 levels will not reach 1000 micromoles mol-1 (0.1%) for decades, CO2 levels in growth chambers and greenhouses routinely exceed that concentration. CO2 levels in life support systems in space can exceed 10000 micromoles mol-1(1%). Numerous studies have examined CO2 effects up to 1000 micromoles mol-1, but biochemical measurements indicate that the beneficial effects of CO2 can continue beyond this concentration. We studied the effects of near-optimal (approximately 1200 micromoles mol-1) and super-optimal CO2 levels (2400 micromoles mol-1) on yield of two cultivars of hydroponically grown wheat (Triticum aestivum L.) in 12 trials in growth chambers. Increasing CO2 from sub-optimal to near-optimal (350-1200 micromoles mol-1) increased vegetative growth by 25% and seed yield by 15% in both cultivars. Yield increases were primarily the result of an increased number of heads per square meter. Further elevation of CO2 to 2500 micromoles mol-1 reduced seed yield by 22% (P < 0.001) in cv. Veery-10 and by 15% (P < 0.001) in cv. USU-Apogee. Super-optimal CO2 did not decrease the number of heads per square meter, but reduced seeds per head by 10% and mass per seed by 11%. The toxic effect of CO2 was similar over a range of light levels from half to full sunlight. Subsequent trials revealed that super-optimal CO2 during the interval between 2 wk before and after anthesis mimicked the effect of constant super-optimal CO2. Furthermore, near-optimal CO2 during the same interval mimicked the effect of constant near-optimal CO2. Nutrient concentration of leaves and heads was not affected by CO2. These results suggest that super-optimal CO2 inhibits some process that occurs near the time of seed set resulting in decreased seed set, seed mass, and yield.

  15. Effects of optimal and supra-optimal salinity stress on antioxidative defence, osmolytes and in vitro growth responses in Sesuvium portulacastrum L

    Microsoft Academic Search

    Vinayak H. Lokhande; Tukaram D. Nikam; Vikas Y. Patade; Mahendra L. Ahire; P. Suprasanna

    2011-01-01

    The effect of optimal and supra-optimal concentrations (0, 200, 400 or 600 mM) of NaCl on the growth, osmotic adjustment and\\u000a antioxidant enzyme defence was studied in the in vitro cultures of Sesuvium portulacastrum. A significant increase in growth, tissue water content (TWC) and fresh to dry weight ratio (FW\\/DW) was observed in the shoots\\u000a exposed to 200 mM salt. Minimum damage

  16. Optimize flue gas settings to promote microalgae growth in photobioreactors via computer simulations.

    PubMed

    He, Lian; Chen, Amelia B; Yu, Yi; Kucera, Leah; Tang, Yinjie

    2013-01-01

    Flue gas from power plants can promote algal cultivation and reduce greenhouse gas emissions(1). Microalgae not only capture solar energy more efficiently than plants(3), but also synthesize advanced biofuels(2-4). Generally, atmospheric CO2 is not a sufficient source for supporting maximal algal growth(5). On the other hand, the high concentrations of CO2 in industrial exhaust gases have adverse effects on algal physiology. Consequently, both cultivation conditions (such as nutrients and light) and the control of the flue gas flow into the photo-bioreactors are important to develop an efficient "flue gas to algae" system. Researchers have proposed different photobioreactor configurations(4,6) and cultivation strategies(7,8) with flue gas. Here, we present a protocol that demonstrates how to use models to predict the microalgal growth in response to flue gas settings. We perform both experimental illustration and model simulations to determine the favorable conditions for algal growth with flue gas. We develop a Monod-based model coupled with mass transfer and light intensity equations to simulate the microalgal growth in a homogenous photo-bioreactor. The model simulation compares algal growth and flue gas consumptions under different flue-gas settings. The model illustrates: 1) how algal growth is influenced by different volumetric mass transfer coefficients of CO2; 2) how we can find optimal CO2 concentration for algal growth via the dynamic optimization approach (DOA); 3) how we can design a rectangular on-off flue gas pulse to promote algal biomass growth and to reduce the usage of flue gas. On the experimental side, we present a protocol for growing Chlorella under the flue gas (generated by natural gas combustion). The experimental results qualitatively validate the model predictions that the high frequency flue gas pulses can significantly improve algal cultivation. PMID:24121788

  17. ISS-Crystal Growth of Photorefractive Materials (BSO): Critical Design Issues for Optimized Data Extraction from Space Experiments

    NASA Technical Reports Server (NTRS)

    Hyers, Robert W.; Motakef, S.; Witt, A. F.; Wuensch, B.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Realization of the full potential of photorefractive materials in device technology is seriously impeded by our inability to achieve controlled formation of critical defects during single crystal growth and by difficulties in meeting the required degree of compositional uniformity on a micro-scale over macroscopic dimensions. The exact nature and origin of the critical defects which control photorefractivity could not as yet be identified because of gravitational interference. There exists, however, strong evidence that the density of defect formation and their spatial distribution are adversely affected by gravitational interference which precludes the establishment of quantifiable and controllable heat and mass transfer conditions during crystal growth. The current, NASA sponsored research at MIT is directed at establishing a basis for the development of a comprehensive approach to the optimization of property control during melt growth of photorefractive materials, making use of the m-g environment, provided in the International Space Station. The objectives to be pursued in m-g research on photorefractive BSO (Bi12SiO20) are: (a) identification of the x-level(s) responsible for photorefractivity in undoped BSO; (b) development of approaches leading to the control of x-level formation at uniform spatial distribution; (c) development of doping and processing procedures for optimization of the critical, application specific parameters, spectral response, sensitivity, response time and matrix stability. The presentation will focus on: the rationale for the justification of the space experiment, ground-based development efforts, design considerations for the space experiments, strategic plan of the space experiments, and approaches to the quantitative analysis of the space experiments.

  18. Models for optimal harvest with convex function of growth rate of a population

    SciTech Connect

    Lyashenko, O.I.

    1995-12-10

    Two models for growth of a population, which are described by a Cauchy problem for an ordinary differential equation with right-hand side depending on the population size and time, are investigated. The first model is time-discrete, i.e., the moments of harvest are fixed and discrete. The second model is time-continuous, i.e., a crop is harvested continuously in time. For autonomous systems, the second model is a particular case of the variational model for optimal control with constraints investigated in. However, the prerequisites and the method of investigation are somewhat different, for they are based on Lemma 1 presented below. In this paper, the existence and uniqueness theorem for the solution of the discrete and continuous problems of optimal harvest is proved, and the corresponding algorithms are presented. The results obtained are illustrated by a model for growth of the light-requiring green alga Chlorella.

  19. Optimizing Performance on Linux Clusters Using Advanced Communication Protocols: Achieving Over 10 Teraflops on a 8.6 Teraflops Linpack-Rated Linux Cluster

    SciTech Connect

    Krishnan, Manoj Kumar; Nieplocha, Jarek

    2005-04-26

    Advancements in high-performance networks (Quadrics, Infiniband or Myrinet) continue to improve the efficiency of modern clusters. However, the average application efficiency is as small fraction of the peak as the system’s efficiency. This paper describes techniques for optimizing application performance on Linux clusters using Remote Memory Access communication protocols. The effectiveness of these optimizations is presented in the context of an application kernel, dense matrix multiplication. The result was achieving over 10 teraflops on HP Linux cluster on which LINPACK performance is measured as 8.6 teraflops.

  20. Discounted optimal growth in the two-sector RSS model: a geometric investigation

    Microsoft Academic Search

    M. Ali Khan; Tapan Mitra

    This paper initiates a comprehensive investigation of discounted optimal growth in the two-sector RSS model as a specific\\u000a instance of the general theory of resource allocation associated with Brock, Gale and McKenzie. For an interval of values\\u000a of a parameter ? formalizing the marginal technical rate of transformation, under zero consumption, of machines from one period\\u000a to the next, we

  1. An Axenic Plant Culture System for Optimal Growth in Long-Term Studies

    Microsoft Academic Search

    Amelia Henry; William Doucette; Jeanette Norton; Scott Jones; Julie Chard; Bruce Bugbee

    2006-01-01

    Thesymbioticco-evolutionofplantsandmicrobesleadstodifficulties in understanding which of the two components is responsible for a given environmental response. Plant-microbe studies greatly benefit from the abilitytogrowplantsinaxenic(sterile)culture.Severalstudieshaveused axenic plant culture systems, but experimental procedures are often poorly documented, the plant growth environment is not optimal, and axenic conditions are not rigorously verified. We developed a unique axenic system using inert components that promotes plant health

  2. Relationships Between Genomic G+C Content, RNA Secondary Structures, and Optimal Growth Temperature in Prokaryotes

    Microsoft Academic Search

    Nicolas Galtier; J. R. Lobry

    1997-01-01

    .   G:C pairs are more stable than A:T pairs because they have an additional hydrogen bond. This has led to many studies on the\\u000a correlation between the guanine+cytosine (G+C) content of nucleic acids and temperature over the last 20 years. We collected\\u000a the optimal growth temperatures (Topt) and the G+C contents of genomic DNA; 23S, 16S, and 5S ribosomal RNAs;

  3. Forced sustained swimming exercise at optimal speed enhances growth of juvenile yellowtail kingfish (Seriola lalandi)

    PubMed Central

    Palstra, Arjan P.; Mes, Daan; Kusters, Kasper; Roques, Jonathan A. C.; Flik, Gert; Kloet, Kees; Blonk, Robbert J. W.

    2015-01-01

    Swimming exercise at optimal speed may optimize growth performance of yellowtail kingfish in a recirculating aquaculture system. Therefore, optimal swimming speeds (Uopt in m s?1 or body lengths s?1, BL s?1) were assessed and then applied to determine the effects of long-term forced and sustained swimming at Uopt on growth performance of juvenile yellowtail kingfish. Uopt was quantified in Blazka-type swim-tunnels for 145, 206, and 311 mm juveniles resulting in values of: (1) 0.70 m s?1 or 4.83 BL s?1, (2) 0.82 m s?1 or 3.25 BL s?1, and (3) 0.85 m s?1 or 2.73 BL s?1. Combined with literature data from larger fish, a relation of Uopt (BL s?1) = 234.07(BL)?0.779 (R2 = 0.9909) was established for this species. Yellowtail kingfish, either forced to perform sustained swimming exercise at an optimal speed of 2.46 BL s?1 (“swimmers”) or allowed to perform spontaneous activity at low water flow (“resters”) in a newly designed 3600 L oval flume (with flow created by an impeller driven by an electric motor), were then compared. At the start of the experiment, ten fish were sampled representing the initial condition. After 18 days, swimmers (n = 23) showed a 92% greater increase in BL and 46% greater increase in BW as compared to resters (n = 23). As both groups were fed equal rations, feed conversion ratio (FCR) for swimmers was 1.21 vs. 1.74 for resters. Doppler ultrasound imaging showed a statistically significant higher blood flow (31%) in the ventral aorta of swimmers vs. resters (44 ± 3 vs. 34 ± 3 mL min?1, respectively, under anesthesia). Thus, growth performance can be rapidly improved by optimal swimming, without larger feed investments. PMID:25620933

  4. The integration of Dow's Fire and Explosion Index into process design and optimization to achieve an inherently safer design

    E-print Network

    Suardin, Jaffee Arizon

    2006-10-30

    and optimization framework is verified by applying it into reactor-distillation column system. The final result is the optimum economic and inherently safer design for the reactor and distillation column system....

  5. Targeting public investments by agro-ecological zone to achieve growth and poverty alleviation goals in rural India

    Microsoft Academic Search

    Shenngen Fan; Peter Hazell; T. Haque

    2000-01-01

    This paper shows that improved technology and rural infrastructure have made important contributions to agricultural growth and poverty reduction in India. However, these effects have varied widely across agro-ecological zones. In the past, the government has devoted more resources to irrigated areas, and this has led to significant production growth and poverty reduction in those areas. However, as investments in

  6. A Comparison of the Effect of Instructional Time and Instructional Program on Reading Achievement Growth of Kindergarten Students

    ERIC Educational Resources Information Center

    Warner, Darlene Ovyn

    2012-01-01

    This dissertation study examined reading achievement among students enrolled in half-day kindergarten (HDK) and full-day kindergarten (FDK) programs. First, a review of the research on reading achievement in students in both HDK and FDK programs was presented. Next, the study, including the research questions, study design, and analysis plan, were…

  7. Thermal preference of juvenile Dover sole (Solea solea) in relation to thermal acclimation and optimal growth temperature.

    PubMed

    Schram, Edward; Bierman, Stijn; Teal, Lorna R; Haenen, Olga; van de Vis, Hans; Rijnsdorp, Adriaan D

    2013-01-01

    Dover sole (Solea solea) is an obligate ectotherm with a natural thermal habitat ranging from approximately 5 to 27°C. Thermal optima for growth lie in the range of 20 to 25°C. More precise information on thermal optima for growth is needed for cost-effective Dover sole aquaculture. The main objective of this study was to determine the optimal growth temperature of juvenile Dover sole (Solea solea) and in addition to test the hypothesis that the final preferendum equals the optimal growth temperature. Temperature preference was measured in a circular preference chamber for Dover sole acclimated to 18, 22 and 28°C. Optimal growth temperature was measured by rearing Dover sole at 19, 22, 25 and 28°C. The optimal growth temperature resulting from this growth experiment was 22.7°C for Dover sole with a size between 30 to 50 g. The temperature preferred by juvenile Dover sole increases with acclimation temperature and exceeds the optimal temperature for growth. A final preferendum could not be detected. Although a confounding effect of behavioural fever on temperature preference could not be entirely excluded, thermal preference and thermal optima for physiological processes seem to be unrelated in Dover sole. PMID:23613837

  8. Methodology, morphology, and optimization of carbon nanotube growth for improved energy storage in a double layer capacitor

    E-print Network

    Ku, Daniel C. (Daniel Chung-Ming), 1985-

    2009-01-01

    The goal of this thesis is to optimize the growth of carbon nanotubes (CNTs) on a conducting substrate for use as an electrode to improve energy density in a double-layer capacitor. The focus has been on several areas, ...

  9. Posttraumatic Growth, Optimism and Openness as Outcomes of a Cognitive-behavioural Intervention for Posttraumatic Stress Reactions

    Microsoft Academic Search

    Christine Knaevelsrud; Alexandra Liedl; Andreas Maercker

    2010-01-01

    The aim of this study was to examine the effect of an Internet-based CBT intervention on posttraumatic growth, openness and optimism. Ninety-six participants suffering from posttraumatic stress reactions were randomly assigned to either the treatment or a waiting-list control condition. We assessed posttraumatic stress reactions, depression and anxiety, posttraumatic growth, optimism and openness to new experiences. We found significant changes

  10. Language and Verbal Memory in Individuals with a History of Autism Spectrum Disorders Who Have Achieved Optimal Outcomes

    ERIC Educational Resources Information Center

    Tyson, Katherine; Kelley, Elizabeth; Fein, Deborah; Orinstein, Alyssa; Troyb, Eva; Barton, Marianne; Eigsti, Inge-Marie; Naigles, Letitia; Schultz, Robert T.; Stevens, Michael; Helt, Molly; Rosenthal, Michael

    2014-01-01

    Some individuals who lose their autism spectrum disorder diagnosis may continue to display subtle weaknesses in language. We examined language and verbal memory in 44 individuals with high-functioning autism (HFA), 34 individuals with "optimal outcomes" (OO) and 34 individuals with typical development (TD). The OO group scored in the…

  11. Cement-retained versus screw-retained implant restorations: Achieving optimal occlusion and esthetics in implant dentistry

    Microsoft Academic Search

    Kenneth S. Hebel; Reena C. Gajjar

    1997-01-01

    Statement of problem. Optimal occlusion and esthetics are goals in prosthetic treatment. Implant dentistry is no exception.Purpose of article. The purpose of this article is to discuss how the choice to use screw-retained or cement-retained implants dramatically influences the occlusion and esthetics. (J Prosthet Dent 1997;77:28-35.)

  12. Simple processes for optimized growth and harvest of Ettlia sp. by pH control using CO2 and light irradiation.

    PubMed

    Yoo, Chan; La, Hyun-Joon; Kim, Sun-Chang; Oh, Hee-Mock

    2015-02-01

    Microalgae cultures show wide range of pH depending on the availability of light and CO2 for their strain specific photosynthesis. Thus, the modulation of light irradiation and CO2 supply can be applied for the pH control of microalgae cultures. The optimal pH of Ettlia sp. YC001, for phototrophic growth and auto-flocculation was investigated by controlling light irradiation and 10% CO2 supply. Ettlia sp. YC001 showed the highest biomass productivity, 96.7?mg?L(-1) ?d(-1) , at pH 8.5. The flocculating activity of Ettlia sp. YC001 showed a sigmoid pattern with pH increase and was above 70% at pH 10.5. Based on these differentiated optimal pH regimes for the growth and flocculation, an integrated process consisting of cultivation and settling vessels was proposed. The integrated process demonstrated that high flocculation activity of Ettlia sp. YC001 could be achieved in the settling vessel with various hydraulic retention times by only irradiation of light to maintain high pH while maintaining the optimal growth in cultivation vessel with the light irradiation and CO2 supply at pH 8.5. Thus, the proposed strategy for pH control would provide a simple, cost-effective, and flexible design and operation for microalgae cultivation-harvest systems. PMID:25182602

  13. Optimal growth of Dunaliella primolecta in axenic conditions to assay herbicides.

    PubMed

    Santín-Montanyá, I; Sandín-España, P; García Baudín, J M; Coll-Morales, J

    2007-01-01

    To develop an assay for herbicides in marine environments using microalgae, we have optimized the specie, cell culture media and physical conditions to obtain maximal cellular densities in a 96 well micro format to allow mass assays. We first surveyed several species of 7 unicellular eukaryotic algae genera (Dunaliella, Tetraselmis, Chlorella, Ellipsoidon, Isochrysis, Nannochloropsis, and Phaeodactylum) for vigorous in vitro axenic growth. Once the genus Dunaliella was selected, Dunaliella primolecta was preferred among 9 species (bioculata, minuta, parva, peircei, polymorpha, primolecta, quartolecta, salina and tertiolecta) because it showed the highest growth rates. The components (oligo elements, sugars, amino acids and vitamins) and conditions (light, CO(2), temperature) of the culture media were further optimized to obtain the highest cellular densities (up to 60x10(6)cellsml(-1)) and the shortest cell cycle duration ( approximately 12h) for D. primolecta. Then the toxicity of four representative herbicides, alloxydim, and sethoxydim (inhibitors of acetyl-coA carboxilase), metamitron (inhibitor of photosynthesis) and clopyralid (inhibitor of respiration), were assayed on the optimal culture conditions for D. primolecta during 96h. The results showed that D. primolecta was susceptible to those herbicides in the following order: metamitron > sethoxydim > alloxydim. In contrast, clopyralid did not have any effects. Therefore, D. primolecta microcultures can be used to assay a large number of samples for the presence of herbicides under a saline environment. PMID:16979216

  14. Experimental analysis and model-based optimization of microalgae growth in photo-bioreactors using flue gas

    E-print Network

    Subramanian, Venkat

    Experimental analysis and model-based optimization of microalgae growth in photo-bioreactors using utilization in algal photo-bioreactors, we performed both model simulations and experimental analysis. First in the photo-bioreactor. Via the dynamic optimization approach (DOA), the model profiled time-dependent CO2

  15. Characterization of local quadratic growth for strong minima in the optimal control of semi-linear elliptic equations

    E-print Network

    Paris-Sud XI, Université de

    Characterization of local quadratic growth for strong minima in the optimal control of semi-linear elliptic equations T´erence Bayen J. Fr´ed´eric Bonnans Francisco J. Silva§ September 11, 2013 Abstract In this article we consider an optimal control problem of a semi-linear elliptic equation, with bound constraints

  16. Academic Abilities in Children and Adolescents with a History of Autism Spectrum Disorders Who Have Achieved Optimal Outcomes

    ERIC Educational Resources Information Center

    Troyb, Eva; Orinstein, Alyssa; Tyson, Katherine; Helt, Molly; Eigsti, Inge-Marie; Stevens, Michael; Fein, Deborah

    2014-01-01

    This study examines the academic abilities of children and adolescents who were once diagnosed with an autism spectrum disorder, but who no longer meet diagnostic criteria for this disorder. These individuals have achieved social and language skills within the average range for their ages, receive little or no school support, and are referred to…

  17. The Role of Maternal Smoking in Effect of Fetal Growth Restriction on Poor Scholastic Achievement in Elementary School

    PubMed Central

    Burstyn, Igor; Kuhle, Stefan; Allen, Alexander C.; Veugelers, Paul

    2012-01-01

    Fetal growth restriction and maternal smoking during pregnancy are independently implicated in lowering intellectual attainment in children. We hypothesized that only reduction of fetal growth that is attributable to extrinsic causes (e.g., maternal smoking) affects intellectual development of a child. Cross-sectional survey of 3,739 students in Nova Scotia (Canada) in 2003 was linked with the perinatal database, parental interviews on socio-demographic factors and the performance on standardized tests when primarily 11–12 years of age, thereby forming a retrospective cohort. Data was analyzed using hierarchical logistic regression with correction for clustering of children within schools. The risk of poor test result among children born small-for-gestational-age (SGA) to mothers who smoked was 29.4%, higher than in any other strata of maternal smoking and fetal growth. The adjusted odds ratio among SGA children born to mothers who smoked was the only one elevated compared to children who were not growth restricted and born to mothers who did not smoke (17.0%, OR = 1.46, 95% CI 1.02, 2.09). Other perinatal, maternal and socio-demographic factors did not alter this pattern of effect modification. Heterogeneity of etiology of fetal growth restriction should be consider in studies that address examine its impact on health over life course. PMID:22470300

  18. Optimization of source-sink dynamics in plant growth for ideotype breeding: a case1 study on maize2

    E-print Network

    Boyer, Edmond

    of source-sink dynamics in plant growth for ideotype breeding: a case1 study on maize2 3 Rui QI ab* , Yuntao a mathematical model of plant2 growth could be possible to design ideotypes and thus leads to new breedingLab, functional-structural model, Zea mays.,2 multi-objective optimization3 Introduction4 In plant breeding

  19. Codon optimization, promoter and expression system selection that achieved high-level production of Yarrowia lipolytica lipase in Pichia pastoris.

    PubMed

    Zhou, Wen-Jing; Yang, Jiang-Ke; Mao, Lin; Miao, Li-Hong

    2015-04-01

    Lipase (EC 3.1.1.3) stands amongst the most important and promising biocatalysts for industrial applications. In this study, in order to realize a high-level expression of the Yarrowia lipolytica lipase gene in Pichia pastoris, we optimized the codon of LIP2 by de novo gene design and synthesis, which significantly improved the lipase expression when compared to the native lip2 gene. We also comparatively analyzed the effects of the promoter types (PAOX1 and PFLD1) and the Pichia expression systems, including the newly developed PichiaPink system, on lipase production and obtained the optimal recombinants. Bench-top scale fermentation studies indicated that the recombinant carrying the codon-optimized lipase gene syn-lip under the control of promoter PAOX1 has a significantly higher lipase production capacity in the fermenter than other types of recombinants. After undergoing methanol inducible expression for 96h, the wet cell weight of Pichia, the lipase activity and the protein content in the fermentation broth reached their highest values of 262g/L, 38,500U/mL and 2.82g/L, respectively. This study has not only greatly facilitated the bioapplication of lipase in industrial fields but the strategies utilized, such as de novo gene design and synthesis, the comparative analysis among promoters and different generations of Pichia expression systems will also be useful as references for future work in this field. PMID:25765312

  20. Further developments in the controlled growth approach for optimal structural synthesis

    NASA Technical Reports Server (NTRS)

    Hajela, P.

    1982-01-01

    It is pointed out that the use of nonlinear programming methods in conjunction with finite element and other discrete analysis techniques have provided a powerful tool in the domain of optimal structural synthesis. The present investigation is concerned with new strategies which comprise an extension to the controlled growth method considered by Hajela and Sobieski-Sobieszczanski (1981). This method proposed an approach wherein the standard nonlinear programming (NLP) methodology of working with a very large number of design variables was replaced by a sequence of smaller optimization cycles, each involving a single 'dominant' variable. The current investigation outlines some new features. Attention is given to a modified cumulative constraint representation which is defined in both the feasible and infeasible domain of the design space. Other new features are related to the evaluation of the 'effectiveness measure' on which the choice of the dominant variable and the linking strategy is based.

  1. Optimizing administration of epidermal growth factor receptor-targeted agents in the treatment of colorectal cancer.

    PubMed

    Van Cutsem, Eric

    2007-10-01

    The monoclonal antibodies against the epidermal growth factor receptor (EGFR) are active in patients with metastatic colorectal cancer (CRC; mCRC). This activity has been shown initially in irinotecan- and chemotherapy-refractory mCRC. The correlation of rash after EGFR inhibitors and activity has led to the concept of the dose until rash study. Clinical trials evaluating this concept are ongoing. However, many unresolved challenges remain regarding this question. New challenges include the development of the most optimal schedule of the EGFR inhibitors and the evaluation of their role in less advanced stages and in the preoperative treatment of liver metastases of CRC. PMID:18021489

  2. Combinatorial Optimization of Heterogeneous Catalysts Used in the Growth of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Verma, Sunita; Delzeit, Lance; Meyyappan, M.; Han, Jie

    2000-01-01

    Libraries of liquid-phase catalyst precursor solutions were printed onto iridium-coated silicon substrates and evaluated for their effectiveness in catalyzing the growth of multi-walled carbon nanotubes (MWNTs) by chemical vapor deposition (CVD). The catalyst precursor solutions were composed of inorganic salts and a removable tri-block copolymer (EO)20(PO)70(EO)20 (EO = ethylene oxide, PO = propylene oxide) structure-directing agent (SDA), dissolved in ethanol/methanol mixtures. Sample libraries were quickly assayed using scanning electron microscopy after CVD growth to identify active catalysts and CVD conditions. Composition libraries and focus libraries were then constructed around the active spots identified in the discovery libraries to understand how catalyst precursor composition affects the yield, density, and quality of the nanotubes. Successful implementation of combinatorial optimization methods in the development of highly active, carbon nanotube catalysts is demonstrated, as well as the identification of catalyst formulations that lead to varying densities and shapes of aligned nanotube towers.

  3. Achieving the full performance of highly efficient columns by optimizing conventional benchmark high-performance liquid chromatography instruments

    Microsoft Academic Search

    Fabrice Gritti; Carl A. Sanchez; Tivadar Farkas; Georges Guiochon

    2010-01-01

    A series of experiments and measurements demonstrate the importance of minimizing the extra-column band broadening contribution of the instrument used. The combination of several measures allowed the achievement of the full potential efficiency of three Kinetex-C18 columns, using a conventional liquid chromatograph. The first measure consists in minimizing the extra-column volume of the instrument, without increasing much its back pressure

  4. Fat-soluble vitamin and micromineral concentrations in preruminant dairy calves fed to achieve different growth rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calf nutrition programs often limit nutrient intake from milk replacer during the first few weeks of life to promote dry-feed intake and early weaning. Recent studies indicate that feeding increased amounts of milk replacer with higher protein concentration improves growth performance and feed effi...

  5. ACHIEVING NEW SOURCE PERFORMANCE STANDARDS (NSPS) EMISSION STANDARDS THROUGH INTEGRATION OF LOW-NOx BURNERS WITH AN OPTIMIZATION PLAN FOR BOILER COMBUSTION

    SciTech Connect

    Wayne Penrod; David Moyeda

    2003-07-01

    The objective of this project is to demonstrate the use of an Integrated Combustion Optimization System to achieve NO{sub x} emissions levels in the range of 0.15 to 0.22 lb/MMBtu while simultaneously enabling increased power output. The project consists of the integration of low-NO{sub x} burners and advanced overfire air technology with various process measurement and control devices on the Holcomb Station Unit 1 boiler. The project includes the use of sophisticated neural networks or other artificial intelligence technologies and complex software that can optimize several operating parameters, including NO{sub x} emissions, boiler efficiency, and CO emissions. The program is being performed in three phases. In Phase I, the boiler is being equipped with sensors that can be used to monitor furnace conditions and coal flow to permit improvements in boiler operation. In Phase II, the boiler will be equipped with burner modifications designed to reduce NO{sub x} emissions and automated coal flow dampers to permit on-line fuel balancing. In Phase III, the boiler will be equipped with an overfire air system to permit deep reductions in NO{sub x} emissions to be achieved. Integration of the overfire air system with the improvements made in Phases I and II will permit optimization of the boiler performance, output, and emissions. During this reporting period, efforts were focused on completion of Phase I and Phase II activities. The low-NO{sub x} burner modifications, the coal flow dampers, and the coal flow monitoring system were procured and installed during a boiler outage in March 2003. During this reporting period, optimization tests were performed to evaluate system performance and identify optimum operating conditions for the installed equipment. The overfire air system process design activities and preliminary engineering design were completed.

  6. Imaging live cells at the nanometer-scale with single-molecule microscopy: obstacles and achievements in experiment optimization for microbiology.

    PubMed

    Haas, Beth L; Matson, Jyl S; DiRita, Victor J; Biteen, Julie S

    2014-01-01

    Single-molecule fluorescence microscopy enables biological investigations inside living cells to achieve millisecond- and nanometer-scale resolution. Although single-molecule-based methods are becoming increasingly accessible to non-experts, optimizing new single-molecule experiments can be challenging, in particular when super-resolution imaging and tracking are applied to live cells. In this review, we summarize common obstacles to live-cell single-molecule microscopy and describe the methods we have developed and applied to overcome these challenges in live bacteria. We examine the choice of fluorophore and labeling scheme, approaches to achieving single-molecule levels of fluorescence, considerations for maintaining cell viability, and strategies for detecting single-molecule signals in the presence of noise and sample drift. We also discuss methods for analyzing single-molecule trajectories and the challenges presented by the finite size of a bacterial cell and the curvature of the bacterial membrane. PMID:25123183

  7. Imaging Live Cells at the Nanometer-Scale with Single-Molecule Microscopy: Obstacles and Achievements in Experiment Optimization for Microbiology

    PubMed Central

    Haas, Beth L.; Matson, Jyl S.; DiRita, Victor J.; Biteen, Julie S.

    2015-01-01

    Single-molecule fluorescence microscopy enables biological investigations inside living cells to achieve millisecond- and nanometer-scale resolution. Although single-molecule-based methods are becoming increasingly accessible to non-experts, optimizing new single-molecule experiments can be challenging, in particular when super-resolution imaging and tracking are applied to live cells. In this review, we summarize common obstacles to live-cell single-molecule microscopy and describe the methods we have developed and applied to overcome these challenges in live bacteria. We examine the choice of fluorophore and labeling scheme, approaches to achieving single-molecule levels of fluorescence, considerations for maintaining cell viability, and strategies for detecting single-molecule signals in the presence of noise and sample drift. We also discuss methods for analyzing single-molecule trajectories and the challenges presented by the finite size of a bacterial cell and the curvature of the bacterial membrane. PMID:25123183

  8. Optimization of the purification methods for recovery of recombinant growth hormone from Paralichthys olivaceus

    NASA Astrophysics Data System (ADS)

    Zang, Xiaonan; Zhang, Xuecheng; Mu, Xiaosheng; Liu, Bin

    2013-03-01

    This study aimed to optimize the purification of recombinant growth hormone from Paralichthys olivaceus. Recombinant flounder growth hormone (r-fGH) was expressed by Escherichia coli in form of inclusion body or as soluble protein under different inducing conditions. The inclusion body was renatured using two recovery methods, i.e., dilution and dialysis. Thereafter, the refolded protein was purified by Glutathione Sepharase 4B affinity chromatography and r-fGH was obtained by cleavage of thrombin. For soluble products, r-fGH was directly purified from the lysates by Glutathione Sepharase 4B affinity chromatography. ELISA-receptor assay demonstrated that despite its low receptor binding activity, the r-fGH purified from refolded inclusion body had a higher yield (2.605 mg L-1) than that from soluble protein (1.964 mg L-1). Of the tested recovery methods, addition of renaturing buffer (pH 8.5) into denatured inclusion body yielded the best recovery rate (17.9%). This work provided an optimized purification method for high recovery of r-fGH, thus contributing to the application of r-fGH to aquaculture.

  9. Language and Verbal Memory in Individuals with a History of Autism Spectrum Disorders Who Have Achieved Optimal Outcomes

    PubMed Central

    Tyson, Katherine; Kelley, Elizabeth; Fein, Deborah; Orinstein, Alyssa; Troyb, Eva; Barton, Marianne; Eigsti, Inge-Marie; Naigles, Letitia; Schultz, Robert T.; Stevens, Michael; Helt, Molly; Rosenthal, Michael

    2013-01-01

    Some individuals who lose their autism spectrum disorder (ASD) diagnosis may continue to display subtle weaknesses in language. We examined language and verbal memory in 44 individuals with high-functioning autism (HFA), 34 individuals with “optimal outcomes” (OO) and 34 individuals with typical development (TD). The OO group scored in the average range or above on all measures and showed few differences from the TD group. The HFA group performed within the average range but showed significantly lower mean performance than the other groups on multiple language measures, even when controlling for VIQ. Results also indicate that OO individuals show strong language abilities in all areas tested, but that their language may show greater reliance on verbal memory. PMID:23982487

  10. Transient Growth Theory Prediction of Optimal Placing of Passive and Active Flow Control Devices for Separation Delay in LPT Airfoils

    NASA Technical Reports Server (NTRS)

    Tumin, Anatoli; Ashpis, David E.

    2003-01-01

    An analysis of the non-modal growth of perturbations in a boundary layer in the presence of a streamwise pressure gradient is presented. The analysis is based on PSE equations for an incompressible fluid. Examples with Falkner-Skan profiles indicate that a favorable pressure gradient decreases the non-modal growth while an unfavorable pressure gradient leads to an increase of the amplification. It is suggested that the transient growth mechanism be utilized to choose optimal parameters of tripping elements on a low-pressure turbine (LPT) airfoil. As an example, a boundary layer flow with a streamwise pressure gradient corresponding to the pressure distribution over a LPT airfoil is considered. It is shown that there is an optimal spacing of the tripping elements and that the transient growth effect depends on the starting point. At very low Reynolds numbers, there is a possibility to enhance the transient energy growth by means of wall cooling.

  11. Aconitase B Is Required for Optimal Growth of Xanthomonas campestris pv. vesicatoria in Pepper Plants

    PubMed Central

    Kirchberg, Janine; Büttner, Daniela; Thiemer, Barbara; Sawers, R. Gary

    2012-01-01

    The aerobic plant pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) colonizes the intercellular spaces of pepper and tomato. One enzyme that might contribute to the successful proliferation of Xcv in the host is the iron-sulfur protein aconitase, which catalyzes the conversion of citrate to isocitrate in the tricarboxylic acid (TCA) cycle and might also sense reactive oxygen species (ROS) and changes in cellular iron levels. Xcv contains three putative aconitases, two of which, acnA and acnB, are encoded by a single chromosomal locus. The focus of this study is aconitase B (AcnB). acnB is co-transcribed with two genes, XCV1925 and XCV1926, encoding putative nucleic acid-binding proteins. In vitro growth of acnB mutants was like wild type, whereas in planta growth and symptom formation in pepper plants were impaired. While acnA, XCV1925 or XCV1926 mutants showed a wild-type phenotype with respect to bacterial growth and in planta symptom formation, proliferation of the acnB mutant in susceptible pepper plants was significantly impaired. Furthermore, the deletion of acnB led to reduced HR induction in resistant pepper plants and an increased susceptibility to the superoxide-generating compound menadione. As AcnB complemented the growth deficiency of an Escherichia coli aconitase mutant, it is likely to be an active aconitase. We therefore propose that optimal growth and survival of Xcv in pepper plants depends on AcnB, which might be required for the utilization of citrate as carbon source and could also help protect the bacterium against oxidative stress. PMID:22493725

  12. An Axenic Plant Culture System for Optimal Growth in Long-Term Studies: Design and Maintenance

    NASA Technical Reports Server (NTRS)

    Henry, Amelia; Doucette, William; Norton, Jeanette; Jones, Scott; Chard, Julie; Bugbee, Bruce

    2006-01-01

    The symbiotic co-evolution of plants and microbes leads to difficulties in understanding which of the two components is responsible for a given environmental response. Plant-microbe studies greatly benefit from the ability to grow plants in axenic (sterile) culture. Several studies have used axenic plant culture systems, but experimental procedures are often poorly documented, the plant growth environment is not optimal, and axenic conditions are not rigorously verified. We developed a unique axenic system using inert components that promotes plant health and can be kept sterile for at least 70 d. Crested wheatgrass (Agropyron cristatum cv. DII) plants were grown in sand within flow-through glass columns that were positively pressured with filtered air. Plant health was optimized by regulating temperature, light level, CO2 concentration, humidity, and nutrients. The design incorporates several novel aspects, such as pretreatment of the sand with Fe, graduated sand layers to optimize the air-water balance of the root zone, and modification of a laminar flow hood to serve as a plant growth chamber. Adaptations of several sterile techniques were necessary for maintenance of axenic conditions. Axenic conditions were verified by plating and staining leachates as well as rhizoplane stain. This system was designed to study nutrient and water stress effects on root exudates, but is useful for assessing a broad range of plant-microbe-environment interactions. Based on total organic C analysis, 74% of exudates was recovered in the leachate, 6% was recovered in the bulk sand, and 17% was recovered in the rhizosphere sand. Carbon in the leachate after 70 d reached 255 micro-g/d. Fumaric, malic, malonic, oxalic, and succinic acids were measured as components of the root exudates.

  13. Simulation Optimization of the Heat Transfer Conditions in Hfcvd Diamond Film Growth Inside Holes

    NASA Astrophysics Data System (ADS)

    Wang, Xinchang; Zhang, Jianguo; Zhang, Tao; Shen, Bin; Sun, Fanghong

    2013-08-01

    Finite volume method (FVM) is adopted in the present investigation to simulate the temperature and reactant gas velocity distributions in hot filament chemical vapor deposition (HFCVD) diamond film growth inside holes, using a detailed 3D computational model well in accordance with the actual reactor. The influences of the heat transfer characteristic of the substrate and the auxiliary heat transfer conditions are firstly studied by control variable method (CVM), including the thermal conductivity of the substrate k, the size of the red bronze support block V(x × y × z), the cooling water flux Qw, the reactant gas flux Qg, the arrangement of the gas outlets Aout and the emissivities of the different solid surfaces ?. Thereafter, the substrate temperature data measured in the actual HFCVD reactor with three chosen groups of parameters are compared with those obtained from the simulations, presenting similar trends and small deviations less than 5%. Moreover, the auxiliary heat transfer conditions are optimized for both the WC-Co and SiC substrates based on the simulation and measurement results, and corresponding deposition parameters are also determined. Furthermore, HFCVD diamond films are deposited on the inner surfaces of both the substrates under the optimized conditions. The characterization results show that high-quality diamond films with uniform thickness and fine-faceted crystals are obtained, indicating that this optimization method focusing on the heat transfer conditions is feasible and correct.

  14. Achieving optimal flatness and surface roughness properties for novel x-ray optic structures formed by dicing saws

    NASA Astrophysics Data System (ADS)

    Wieczorek, Michael; Khachatryan, Ruben; Shvyd'ko, Yuri; Smith, Robert H.; Iwasaki, Kenichi; Miller, Suzanne; Qian, Jun; Huang, Xianrong; Assoufid, Lahsen

    2012-10-01

    Crystal-based x-ray optics are widely used in the synchrotron radiation field. Such optics include monochromators, channel-cut crystals, spectral analyzers, and phase plates that are generally made with standard fabrication tools such as grinders, ultrasonic mills, blade saws, and wire saws. However, modern synchrotron radiation instruments require more complicated and high-precision crystal structures that cannot be fabricated by these conventional tools. Examples include narrow channels and crystal cavities that require smooth and strain-free sidewalls or inner surfaces. Since it is extremely difficult to polish such surfaces by conventional means, specialized cutting tools are required to make the as-cut surfaces as smooth as possible. A possible way to obtain such smooth surfaces is to use a dicing saw as a fabrication tool - a tool typically used in the microelectronics industry to cut or dice semiconductor and other materials. Here we present our studies on the use of dicing saws for cutting innovative, monolithic, x-ray optic devices comprised of tall, narrow-standing, thin crystal-plate arrays. We report cutting parameters that include the rotational speed of the cutting blade (a.k.a. spindle speed), cutting speed (a.k.a. feed rate), number of passes for each cut depth (if required), and diamond grit size for producing the flattest and most smooth side walls. Blade type and construction (sintered, Ni, and resin) also play critical roles in achieving optimum results. The best experimental data obtained produced an average surface roughness of 49 nm and a peak-to-valley flatness of 3625 nm. By achieving these results, we have been able to assist experimenters in the synchrotron radiation field in their efforts to create functional and novel optical devices.

  15. Optimized polymeric film-based nitric oxide delivery inhibits bacterial growth in a mouse burn wound model.

    PubMed

    Brisbois, Elizabeth J; Bayliss, Jill; Wu, Jianfeng; Major, Terry C; Xi, Chuanwu; Wang, Stewart C; Bartlett, Robert H; Handa, Hitesh; Meyerhoff, Mark E

    2014-10-01

    Nitric oxide (NO) has many biological roles (e.g. antimicrobial agent, promoter of angiogenesis, prevention of platelet activation) that make NO releasing materials desirable for a variety of biomedical applications. Localized NO release can be achieved from biomedical grade polymers doped with diazeniumdiolated dibutylhexanediamine (DBHD/N2O2) and poly(lactic-co-glycolic acid) (PLGA). In this study, the optimization of this chemistry to create film/patches that can be used to decrease microbial infection at wound sites is examined. Two polyurethanes with different water uptakes (Tecoflex SG-80A (6.2±0.7wt.%) and Tecophilic SP-60D-20 (22.5±1.1wt.%)) were doped with 25wt.% DBHD/N2O2 and 10wt.% of PLGA with various hydrolysis rates. Films prepared with the polymer that has the higher water uptake (SP-60D-20) were found to have higher NO release and for a longer duration than the polyurethane with the lower water uptake (SG-80A). The more hydrophilic polymer enhances the hydrolysis rate of the PLGA additive, thereby providing a more acidic environment that increases the rate of NO release from the NO donor. The optimal NO releasing and control SG-80A patches were then applied to scald burn wounds that were infected with Acinetobacter baumannii. The NO released from these patches applied to the wounds is shown to significantly reduce the A. baumannii infection after 24h (?4 log reduction). The NO release patches are also able to reduce the level of transforming growth factor-? in comparison to controls, which can enhance re-epithelialization, decrease scarring and reduce migration of bacteria. The combined DBHD/N2O2 and PLGA-doped polymer patches, which could be replaced periodically throughout the wound healing process, demonstrate the potential to reduce risk of bacterial infection and promote the overall wound healing process. PMID:24980058

  16. High quality p-type Ag-doped ZnO thin films achieved under elevated growth temperatures.

    PubMed

    Myers, Michelle A; Lee, Joon Hwan; Bi, Zhenxing; Wang, Haiyan

    2012-04-11

    By correlating the effects of substrate temperature, oxygen pressure and laser energy on the electrical and microstructural properties of Ag-doped ZnO films grown on a sapphire (0001) substrate, p-type conductivity is achieved under various substrate temperatures in the wide range of 250-750?°C. All of the samples were deposited by pulsed-laser deposition under various designed conditions. Hall measurements indicate that the best conductivity is achieved in Ag-ZnO films under a substrate temperature of 500?°C, a partial oxygen pressure of 250-300 mTorr and laser energy between 330 and 345 mJ. The hole-carrier concentration is 2.29 × 10(18) cm(-3), the resistivity is 0.9 ? cm and the mobility is 3.03 cm(2) V(-1) s(-1). Transmission-electron microscopy (TEM) studies on the p-type films reveal similar microstructural properties to one another, but different properties to that of the n-type films deposited at the same temperatures with different deposition parameters. PMID:22417979

  17. Technology for monitoring shot-level light source performance data to achieve high-optimization of lithography processes

    NASA Astrophysics Data System (ADS)

    Moriya, Masato; Ochiai, Hideyuki; Watabe, Yoshinobu; Ishida, Keisuke; Masuda, Hiroyuki; Sasaki, Youichi; Kumazaki, Takahito; Kurosu, Akihiko; Ohta, Takeshi; Kakizaki, Kouji; Matsunaga, Takashi; Mizoguchi, Hakaru

    2014-03-01

    Gigaphoton has developed a new monitoring system that provides shot-level light source performance data to FDC systems during exposure time. The system provides basic monitoring data (e.g. Energy, Wavelength, Bandwidth, etc.) and beam performance data, such as Beam Profile, Pointing, Divergence, Polarization can also be monitored using a new metrology tool called the Beam Performance Monitor (BPM) module. During exposure time the system automatically identifies the start and end timing of the wafer and each shot based on the burst of firing signals from the scanner, and stores the measured data in sequence. The stored data is sorted by wafer or by shot, and sent to REDeeM Piece which in turn converts the data to the user's protocol and send it to the FDC system. The user also has the option to directly view or download the stored data using a GUI. Through this monitoring system, users can manage light sources data at the shot or reticle level to facilitate optimization of performance and running cost of the light source for each process. This monitoring system can be easily retrofitted to Gigaphoton's current ArF laser light sources. The beam splitter of the BPM was specially designed to bend only a small fraction of the source beam, so we are able to simply install the BPM without the need for special optical alignment.

  18. Sensitivity Analysis and Optimization of Enclosure Radiation with Applications to Crystal Growth

    NASA Technical Reports Server (NTRS)

    Tiller, Michael M.

    1995-01-01

    In engineering, simulation software is often used as a convenient means for carrying out experiments to evaluate physical systems. The benefit of using simulations as 'numerical' experiments is that the experimental conditions can be easily modified and repeated at much lower cost than the comparable physical experiment. The goal of these experiments is to 'improve' the process or result of the experiment. In most cases, the computational experiments employ the same trial and error approach as their physical counterparts. When using this approach for complex systems, the cause and effect relationship of the system may never be fully understood and efficient strategies for improvement never utilized. However, it is possible when running simulations to accurately and efficiently determine the sensitivity of the system results with respect to simulation to accurately and efficiently determine the sensitivity of the system results with respect to simulation parameters (e.g., initial conditions, boundary conditions, and material properties) by manipulating the underlying computations. This results in a better understanding of the system dynamics and gives us efficient means to improve processing conditions. We begin by discussing the steps involved in performing simulations. Then we consider how sensitivity information about simulation results can be obtained and ways this information may be used to improve the process or result of the experiment. Next, we discuss optimization and the efficient algorithms which use sensitivity information. We draw on all this information to propose a generalized approach for integrating simulation and optimization, with an emphasis on software programming issues. After discussing our approach to simulation and optimization we consider an application involving crystal growth. This application is interesting because it includes radiative heat transfer. We discuss the computation of radiative new factors and the impact this mode of heat transfer has on our approach. Finally, we will demonstrate the results of our optimization.

  19. ACHIEVING NEW SOURCE PERFORMANCE STANDARDS (NSPS) EMISSION STANDARDS THROUGH INTEGRATION OF LOW-NOx BURNERS WITH AN OPTIMIZATION PLAN FOR BOILER COMBUSTION

    SciTech Connect

    Wayne Penrod; David Moyeda

    2003-04-01

    The objective of this project is to demonstrate the use of an Integrated Combustion Optimization System to achieve NO{sub x} emissions levels in the range of 0.15 to 0.22 lb/MMBtu while simultaneously enabling increased power output. The project consists of the integration of low-NO{sub x} burners and advanced overfire air technology with various process measurement and control devices on the Holcomb Station Unit 1 boiler. The project includes the use of sophisticated neural networks or other artificial intelligence technologies and complex software that can optimize several operating parameters, including NO{sub x} emissions, boiler efficiency, and CO emissions. The program is being performed in three phases. In Phase I, the boiler is being equipped with sensors that can be used to monitor furnace conditions and coal flow to permit improvements in boiler operation. In Phase II, the boiler will be equipped with burner modifications designed to reduce NO{sub x} emissions and automated coal flow dampers to permit on-line fuel balancing. In Phase III, the boiler will be equipped with an overfire air system to permit deep reductions in NO{sub x} emissions to be achieved. Integration of the overfire air system with the improvements made in Phases I and II will permit optimization of the boiler performance, output, and emissions. During this reporting period, efforts were focused on Phase I and Phase II activities. The furnace sensors were procured and installed in February 2003. Baseline testing was performed following the sensor installation. The low-NO{sub x} burner modifications, the coal flow dampers, and the coal flow monitoring system were procured and installed during a boiler outage in March 2003. Process design activities were performed to support design of the equipment installed and to develop specifications for the overfire air system. The overfire air system preliminary engineering design was initiated.

  20. Growth Optimization of Metal-polar III-Nitride High-electron-mobility Transistor Structures by Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Kaun, Stephen William

    GaN-based high-electron-mobility transistors (HEMTs) will play an important role in the next generation of high-frequency amplifiers and power-switching devices. Since parasitic conduction (leakage) through the GaN buffer layer and (Al,Ga,In)N barrier reduces the efficiency of operation, HEMT performance hinges on the epitaxial quality of these layers. Increasing the sheet charge density and mobility of the two-dimensional electron gas (2DEG) is also essential for reducing the channel resistance and improving output. The growth conditions applied in plasma-assisted molecular beam epitaxy (PAMBE) and ammonia-based molecular beam epitaxy (NH3-MBE) that result in high-quality metal-polar HEMT structures are described. The effects of threading dislocations on the gate leakage and channel conductivity of AlGaN/GaN HEMTs were studied in detail. For this purpose, a series of HEMT structures were grown on GaN templates with threading dislocation densities (TDDs) that spanned three orders of magnitude. There was a clear trend of reduced gate leakage with reduced TDD for HEMTs grown by Ga-rich PAMBE; however, a reduction in TDD also entailed an increase in buffer leakage. By reducing the unintentionally doped (UID) GaN buffer thickness and including an AlGaN back barrier, a HEMT regrown by Ga-rich PAMBE on low-TDD free-standing (FS) GaN (~5 x 107 cm-2 TDD) yielded a three-terminal breakdown voltage greater than 50 V and a power output (power-added efficiency) of 6.7 W/mm (50 %) at 4 GHz with a 40 V drain bias. High TDD was then shown to severely degrade the 2DEG mobility of AlxGa1-xN/GaN (x = 0.24, 0.12, 0.06) and AlGaN/AlN/GaN heterostructures grown by Ga-rich PAMBE. By regrowing on low-TDD FS GaN and including a 2.5 nm AlN interlayer, an Al0.24Ga0.76N/AlN/GaN heterostructure achieved a room temperature (RT) 2DEG sheet resistance of 169 ?/?. As evidenced by atom probe tomography, the AlN interlayer grown by Ga-rich PAMBE was pure with abrupt interfaces. The pure AlN interlayer greatly reduced alloy-related scattering. When AlGaN/AlN/GaN heterostructures were grown by NH3-MBE at 820 °C, the 2DEG sheet density was lower than expected. These AlN interlayers were shown to have a significant concentration of Ga impurities by atom probe tomography. The source of these impurities was most likely the decomposition of the underlying GaN layers, as reduction of the growth temperature below 750 °C yielded a much lower concentration of Ga impurities. Flux optimization and application of an In surfactant was necessary to reduce the interface roughness in AlGaN/AlN/GaN heterostructures grown by NH3-MBE at low temperature, yielding sheet resistances below 300 ?/?. The growth of InAlN/(GaN)/(AlN)/GaN heterostructures with lattice-matched In0.17Al0.83N barriers by N-rich PAMBE is also described. Through flux optimization, the columnar microstructure previously observed in N-rich PAMBE-grown InAlN layers was eliminated. By including a 3 nm AlN interlayer and 2 nm GaN interlayer, an In0.17Al0.83N/GaN/AlN/GaN heterostructure regrown on low-TDD FS GaN achieved an exceptionally low RT 2DEG sheet resistance of 145 ?/?.

  1. Importance of growth temperature on achieving lattice-matched and strained InAlN/GaN heterostructure by plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Jeganathan, K.; Shimizu, M.

    2014-09-01

    We investigate the role of growth temperature on the optimization of lattice-matched In0.17Al0.83N/GaN heterostructure and its structural evolutions along with electrical transport studies. The indium content gradually reduces with the increase of growth temperature and approaches lattice-matched with GaN having very smooth and high structural quality at 450°C. The InAlN layers grown at high growth temperature (480°C) retain very low Indium content of ˜ 4 % in which cracks are mushroomed due to tensile strain while above lattice matched (>17%) layers maintain crack-free compressive strain nature. The near lattice-matched heterostructure demonstrate a strong carrier confinement with very high two-dimensional sheet carrier density of ˜2.9 × 1013 cm-2 with the sheet resistance of ˜450 ?/? at room temperature as due to the manifestation of spontaneous polarization charge differences between InAlN and GaN layers.

  2. Importance of growth temperature on achieving lattice-matched and strained InAlN/GaN heterostructure by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Jeganathan, K., E-mail: kjeganathan@yahoo.com [Centre for Nanoscience and Nanotechnology, School of Physics, Bharathidasan University, Tiruchirappalli-620 024, Tamil Nadu (India); Shimizu, M., E-mail: mitsu.shimizu@aist.go.jp [Advanced Power Electronics Research Center, National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan. (Japan)

    2014-09-15

    We investigate the role of growth temperature on the optimization of lattice-matched In{sub 0.17}Al{sub 0.83}N/GaN heterostructure and its structural evolutions along with electrical transport studies. The indium content gradually reduces with the increase of growth temperature and approaches lattice-matched with GaN having very smooth and high structural quality at 450ºC. The InAlN layers grown at high growth temperature (480ºC) retain very low Indium content of ? 4 % in which cracks are mushroomed due to tensile strain while above lattice matched (>17%) layers maintain crack-free compressive strain nature. The near lattice-matched heterostructure demonstrate a strong carrier confinement with very high two-dimensional sheet carrier density of ?2.9 × 10{sup 13} cm{sup ?2} with the sheet resistance of ?450 ?/? at room temperature as due to the manifestation of spontaneous polarization charge differences between InAlN and GaN layers.

  3. Journal of Power Sources, Vol.165, issue 2, March 2007, pp.819-832. Abstract--Power management strategy is as significant as component sizing in achieving optimal fuel economy of a

    E-print Network

    Peng, Huei

    strategy is as significant as component sizing in achieving optimal fuel economy of a fuel cell hybrid demonstrate that combined optimization can efficiently provide excellent fuel economy. 1. Introduction Power management strategy and component sizing affect vehicle performance and fuel economy considerably in hybrid

  4. In situ growth optimization in focused electron-beam induced deposition

    PubMed Central

    Weirich, Paul M; Winhold, Marcel; Huth, Michael

    2013-01-01

    Summary We present the application of an evolutionary genetic algorithm for the in situ optimization of nanostructures that are prepared by focused electron-beam-induced deposition (FEBID). It allows us to tune the properties of the deposits towards the highest conductivity by using the time gradient of the measured in situ rate of change of conductance as the fitness parameter for the algorithm. The effectiveness of the procedure is presented for the precursor W(CO)6 as well as for post-treatment of Pt–C deposits, which were obtained by the dissociation of MeCpPt(Me)3. For W(CO)6-based structures an increase of conductivity by one order of magnitude can be achieved, whereas the effect for MeCpPt(Me)3 is largely suppressed. The presented technique can be applied to all beam-induced deposition processes and has great potential for a further optimization or tuning of parameters for nanostructures that are prepared by FEBID or related techniques. PMID:24367761

  5. Real-time optical monitoring of microbial growth using optimal combination of light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kobayashi, Ken-ichi; Yamada, Takeshi; Hiraishi, Akira; Nakauchi, Shigeki

    2012-12-01

    We developed a real-time optical monitoring system consisting of a monochrome complementary metal-oxide semiconductor (CMOS) camera and two light-emitting diodes (LEDs) with a constant temperature incubator for the rapid detection of microbial growth on solid media. As a target organism, we used Alicyclobacillus acidocaldarius, which is an acidophilic thermophilic endospore-forming bacterium able to survive in pasteurization processes and grow in acidic drink products such as apple juice. This bacterium was cultured on agar medium with a redox dye applied to improve detection sensitivity. On the basis of spectroscopic properties of the colony, medium, and LEDs, an optimal combination of two LED illuminations was selected to maximize the contrast between the colony and medium areas. We measured A. acidocaldarius and Escherichia coli at two different dilution levels using these two LEDs. From the results of time-course changes in the number of detected pixels in the detection images, a similar growth rate was estimated amongst the same species of microbes, regardless of the dilution level. This system has the ability to detect a colony of approximately 26 ?m in diameter in a detection image, and it can be interpreted that the size corresponds to less than 20 ?m diameter in visual inspection.

  6. Selecting and optimizing eco-physiological parameters of Biome-BGC to reproduce observed woody and leaf biomass growth of Eucommia ulmoides plantation in China using Dakota optimizer

    NASA Astrophysics Data System (ADS)

    Miyauchi, T.; Machimura, T.

    2013-12-01

    In the simulation using an ecosystem process model, the adjustment of parameters is indispensable for improving the accuracy of prediction. This procedure, however, requires much time and effort for approaching the simulation results to the measurements on models consisting of various ecosystem processes. In this study, we tried to apply a general purpose optimization tool in the parameter optimization of an ecosystem model, and examined its validity by comparing the simulated and measured biomass growth of a woody plantation. A biometric survey of tree biomass growth was performed in 2009 in an 11-year old Eucommia ulmoides plantation in Henan Province, China. Climate of the site was dry temperate. Leaf, above- and below-ground woody biomass were measured from three cut trees and converted into carbon mass per area by measured carbon contents and stem density. Yearly woody biomass growth of the plantation was calculated according to allometric relationships determined by tree ring analysis of seven cut trees. We used Biome-BGC (Thornton, 2002) to reproduce biomass growth of the plantation. Air temperature and humidity from 1981 to 2010 was used as input climate condition. The plant functional type was deciduous broadleaf, and non-optimizing parameters were left default. 11-year long normal simulations were performed following a spin-up run. In order to select optimizing parameters, we analyzed the sensitivity of leaf, above- and below-ground woody biomass to eco-physiological parameters. Following the selection, optimization of parameters was performed by using the Dakota optimizer. Dakota is an optimizer developed by Sandia National Laboratories for providing a systematic and rapid means to obtain optimal designs using simulation based models. As the object function, we calculated the sum of relative errors between simulated and measured leaf, above- and below-ground woody carbon at each of eleven years. In an alternative run, errors at the last year (at the field survey) were weighted for priority. We compared some gradient-based global optimization methods of Dakota starting with the default parameters of Biome-BGC. In the result of sensitive analysis, carbon allocation parameters between coarse root and leaf, between stem and leaf, and SLA had high contribution on both leaf and woody biomass changes. These parameters were selected to be optimized. The measured leaf, above- and below-ground woody biomass carbon density at the last year were 0.22, 1.81 and 0.86 kgC m-2, respectively, whereas those simulated in the non-optimized control case using all default parameters were 0.12, 2.26 and 0.52 kgC m-2, respectively. After optimizing the parameters, the simulated values were improved to 0.19, 1.81 and 0.86 kgC m-2, respectively. The coliny global optimization method gave the better fitness than efficient global and ncsu direct method. The optimized parameters showed the higher carbon allocation rates to coarse roots and leaves and the lower SLA than the default parameters, which were consistent to the general water physiological response in a dry climate. The simulation using the weighted object function resulted in the closer simulations to the measurements at the last year with the lower fitness during the previous years.

  7. Achieving New Source Performance Standards (NSPS) Emission Standards Through Integration of Low-NOx Burners with an Optimization Plan for Boiler Combustion

    SciTech Connect

    Wayne Penrod

    2006-12-31

    The objective of this project was to demonstrate the use of an Integrated Combustion Optimization System to achieve NO{sub X} emission levels in the range of 0.15 to 0.22 lb/MMBtu while simultaneously enabling increased power output. The project plan consisted of the integration of low-NO{sub X} burners and advanced overfire air technology with various process measurement and control devices on the Holcomb Station Unit 1 boiler. The plan included the use of sophisticated neural networks or other artificial intelligence technologies and complex software to optimize several operating parameters, including NO{sub X} emissions, boiler efficiency, and CO emissions. The program was set up in three phases. In Phase I, the boiler was equipped with sensors that can be used to monitor furnace conditions and coal flow to permit improvements in boiler operation. In Phase II, the boiler was equipped with burner modifications designed to reduce NO{sub X} emissions and automated coal flow dampers to permit on-line fuel balancing. In Phase III, the boiler was to be equipped with an overfire air system to permit deep reductions in NO{sub X} emissions. Integration of the overfire air system with the improvements made in Phases I and II would permit optimization of boiler performance, output, and emissions. This report summarizes the overall results from Phases I and II of the project. A significant amount of data was collected from the combustion sensors, coal flow monitoring equipment, and other existing boiler instrumentation to monitor performance of the burner modifications and the coal flow balancing equipment.

  8. Optimization of Plant Growth-Promoting Bacteria-Assisted Phytostabilization of Mine Tailings

    PubMed Central

    Grandlic, Christopher J.; Palmer, Michael W.; Maier, Raina M.

    2009-01-01

    Recent studies have indicated that plant growth-promoting bacteria (PGPB) can improve revegetation of arid mine tailings as measured by increased biomass production. The goals of the present study were first to evaluate how mode of application of known PGPB affects plant growth, and second to evaluate the effect of this inoculation on rhizosphere microbial community structure. PGPB application strategies investigated include preliminary surface sterilization of seeds (a common practice in phytoremediation trials) followed by a comparison of two application methods; immersion and alginate encapsulation. Results with two native desert plant species, Atriplex lentiformis and Buchloe dactyloides, suggest that seed surface sterilization prior to inoculation is not necessary to achieve beneficial effects of introduced PGPB. Both PGPB application techniques generally enhanced plant growth although results were both plant and PGPB specific. These results demonstrate that alginate encapsulation, which allows for long-term storage and easier application to seeds, is an effective way to inoculate PGPB. In addition, the influence of PGPB application on B. dactyloides rhizosphere community structure was evaluated using PCR-DGGE (denaturing gradient gel electrophoresis) analysis of bacterial DNA extracted from rhizosphere samples collected 75 d following planting. A comparative analysis of DGGE profiles was performed using canonical correspondence analysis (CCA). DGGE-CCA showed that rhizosphere community profiles from PGPB-inoculated treatments are significantly different from both uninoculated tailings rhizosphere profiles and profiles from the compost used to amend the tailings. Further, community profiles from B. dactyloides inoculated with the best performing PGPB (Arthro mix) were significantly different from two other PGPB tested. These results suggest that introduced PGPB have the potential to influence the development of the rhizosphere community structure found in plants grown in mine tailings. PMID:20161141

  9. Toroidal coil counter-current chromatography. Achievement of high resolution by optimizing flow-rate, rotation speed, sample volume and tube length.

    PubMed

    Matsuda, K; Matsuda, S; Ito, Y

    1998-05-29

    This paper deals with optimization of a new seal-free compact toroidal coil centrifuge to achieve high resolution in analytical counter-current chromatography (CCC). Toroidal coil CCC (hydrostatic motion) has advantages compared with high-speed CCC (efficiently mixing solution with planetary motion) in the separation of protein or easily emulsified samples. A toroidal coil separation column of 0.4 mm I.D. PTFE tubing was accommodated around the periphery of the cylindrical centrifuge bowl. Using a two-phase solvent system composed of chloroform-acetic acid-0.1 M hydrochloric acid (2:2:1, v/v/v) and a set of dinitrophenyl-amino acids as test samples, a series of experiments was performed with parameters such as the column length, sample volume, flow-rate, elution mode of the mobile phase and rotation speed. The highest efficiency, over 10,000 theoretical plates, was achieved with a 100 m long coiled tube and an 11 ml total capacity at a flow-rate of 0.01 ml/min at 800 rpm. PMID:9652111

  10. Heifer body weight gain and reproductive achievement in response to protein and energy supplementation while grazing dormant range forage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heifers grazing winter range require supplemental nutrients to compliment dormant forage to achieve optimal growth and performance. A study was conducted to evaluate nutritional environment and effect of different supplementation strategies for developing heifers grazing dormant winter range. Eigh...

  11. Optimization of nucleation and buffer layer growth for improved GaN quality

    NASA Astrophysics Data System (ADS)

    Hertkorn, J.; Brückner, P.; Thapa, S. B.; Wunderer, T.; Scholz, F.; Feneberg, M.; Thonke, K.; Sauer, R.; Beer, M.; Zweck, J.

    2007-10-01

    By accurately optimizing the growth conditions for an oxygen doped AlN nucleation layer and for the subsequent epitaxial process the crystal quality of our GaN layers could be improved drastically. In X-ray diffraction analyses we observed FWHM values of 39 and 114 arcsec for the symmetric (0 0 4)- and asymmetric (1 1 4)-reflection, respectively. Consequently, the nominally undoped samples showed semi-insulating behavior in Hall measurements. By in situ deposition of a SiN interlayer, the dislocation density could be reduced by more than a factor of 2, reaching a value of 4×108 cm-2 as confirmed by transmission electron microscopy and etch pit density counting. Samples with this low dislocation density showed an extremely narrow X-ray FWHM of 71 arcsec for the asymmetric (1 1 4)-reflection along with a narrow linewidth of 870 ?eV in photoluminescence (PL) for the donor bound exciton (D 0X) at a temperature of 10 K. Atomic force microscopy yielded a very low rms roughness value of about 0.14 nm across a 4 ?m2 scan area. Finally the excellent crystal quality could be confirmed by growing AlGaN/AlN/GaN high electron mobility transistor structures with reverse breakdown voltages ?1000 V and a very low sheet resistance of 330 ?/?.

  12. X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions

    SciTech Connect

    O, Se Young [Magnetic Materials Group, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); School of Nano and Advanced Materials Engineering, Changwon National University, 9 Sarim-dong, Changwon, Gyeongnam 641-773 (Korea, Republic of); Lee, Chan-Gyu [School of Nano and Advanced Materials Engineering, Changwon National University, 9 Sarim-dong, Changwon, Gyeongnam 641-773 (Korea, Republic of); Shapiro, Alexander J.; Egelhoff, William F. Jr.; Mallett, Jonathan; Pong, Philip W. T. [Magnetic Materials Group, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Vaudin, Mark D.; Ruglovsky, Jennifer L. [Ceramic Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2008-04-01

    We have carried out a systematic study optimizing the MgO growth via preparation and sputtering conditions and underlayer structures. It was found that to prevent water vapor which is detrimental to MgO (200) growth, the chamber pressure needs to be reduced below 10{sup -8} Torr. Simple underlayers such as 5 nm CoFeB tend to give better MgO, but we have also succeeded in growing MgO on more complicated underlayers such as 1 Ta/20 Au/5 Co{sub 40}Fe{sub 40}B{sub 20} and 1 Ta/20 conetic (Ni{sub 77}Fe{sub 14}Cu{sub 5}Mo{sub 4})/1.5 Co{sub 40}Fe{sub 40}B{sub 20} (units in nanometers). We accomplished this by extensive baking of the deposition chamber and use of Ti-getter films. Short sputtering distance and high sputtering power were found to optimize MgO deposition. We found that both preparation and sputtering conditions have important effects on the MgO growth. X-ray diffraction analysis was used as the characterization tool for optimizing the MgO growth conditions.

  13. Finding an optimal rehabilitation paradigm after stroke: enhancing fiber growth and training of the brain at the right moment

    PubMed Central

    Wahl, Anna-Sophia; Schwab, Martin E.

    2014-01-01

    After stroke the central nervous system reveals a spectrum of intrinsic capacities to react as a highly dynamic system which can change the properties of its circuits, form new contacts, erase others, and remap related cortical and spinal cord regions. This plasticity can lead to a surprising degree of spontaneous recovery. It includes the activation of neuronal molecular mechanisms of growth and of extrinsic growth promoting factors and guidance signals in the tissue. Rehabilitative training and pharmacological interventions may modify and boost these neuronal processes, but almost nothing is known on the optimal timing of the different processes and therapeutic interventions and on their detailed interactions. Finding optimal rehabilitation paradigms requires an optimal orchestration of the internal processes of re-organization and the therapeutic interventions in accordance with defined plastic time windows. In this review we summarize the mechanisms of spontaneous plasticity after stroke and experimental interventions to enhance growth and plasticity, with an emphasis on anti-Nogo-A immunotherapy. We highlight critical time windows of growth and of rehabilitative training and consider different approaches of combinatorial rehabilitative schedules. Finally, we discuss potential future strategies for designing repair and rehabilitation paradigms by introducing a “3 step model”: determination of the metabolic and plastic status of the brain, pharmacological enhancement of its plastic mechanisms, and stabilization of newly formed functional connections by rehabilitative training. PMID:25018717

  14. Exploring How Technology Growth Limits Impact Optimal Carbon dioxide Mitigation Pathways

    EPA Science Inventory

    Energy system optimization models prescribe the optimal mix of technologies and fuels for meeting energy demands over a time horizon, subject to energy supplies, demands, and other constraints. When optimizing, these models will, to the extent allowed, favor the least cost combin...

  15. The Application of Various Nonlinear Models to Describe Academic Growth Trajectories: An Empirical Analysis Using Four-Wave Longitudinal Achievement Data from a Large Urban School District

    ERIC Educational Resources Information Center

    Shin, Tacksoo

    2012-01-01

    This study introduced various nonlinear growth models, including the quadratic conventional polynomial model, the fractional polynomial model, the Sigmoid model, the growth model with negative exponential functions, the multidimensional scaling technique, and the unstructured growth curve model. It investigated which growth models effectively…

  16. Solving optimal growth models with vintage capital: The dynamic programming approach

    Microsoft Academic Search

    Giorgio Fabbri; Fausto Gozzi

    2008-01-01

    This paper deals with an endogenous growth model with vintage capital and, more precisely, with the AK model proposed in [R. Boucekkine, O. Licandro, L.A. Puch, F. del Rio, Vintage capital and the dynamics of the AK model, J. Econ. Theory 120 (1) (2005) 39–72]. In endogenous growth models the introduction of vintage capital allows to explain some growth facts

  17. Dimensions, maximal growth sites, and optimization in the dielectric breakdown model

    Microsoft Academic Search

    Joachim Mathiesen; Mogens H. Jensen; Jan Øystein Haavig Bakke

    2008-01-01

    We study the growth of fractal clusters in the dielectric breakdown model (DBM) by means of iterated conformal mappings. In particular we investigate the fractal dimension and the maximal growth site (measured by the Hoelder exponent alphamin ) as a function of the growth exponent eta of the DBM model. We do not find evidence for a phase transition from

  18. Utilizing of protein splicing phenomenon for optimization of obtaining and purification of the recombinant human growth hormone

    E-print Network

    P. L. Starokadomskyy; O. V. Okunev; L. V. Dubey

    2006-12-05

    Protein splicing is a post-translational autocatalystic excision of internal protein sequence (intein) with the subsequent ligation of the flanking polypeptides (exteins). The high specificity of excision ensured by intein makes it possible to use a phenomenon of protein splicing for the biotechnology purposes. The aim of this work was optimization of obtaining and purification of the recombinant human growth hormone using the protein splicing. It was experimentally demonstrated that the use of modified intein as auto-removal affine marker makes it possible to perform the rapid and cheap isolation of the recombinant protein Hgh. Furthermore, this approach allows to obtain the human growth hormone with native N-terminus, without formyl-metionine. Key words: intein, human growth hormone, protein splicing

  19. Optimism

    PubMed Central

    Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.

    2010-01-01

    Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998

  20. Project Luna Succendo: The Lunar Evolutionary Growth-Optimized (LEGO) Reactor

    NASA Astrophysics Data System (ADS)

    Bess, John Darrell

    A final design has been established for a basic Lunar Evolutionary Growth-Optimized (LEGO) Reactor using current and near-term technologies. The LEGO Reactor is a modular, fast-fission, heatpipe-cooled, clustered-reactor system for lunar-surface power generation. The reactor is divided into subcritical units that can be safely launched within lunar shipments from the Earth, and then emplaced directly into holes drilled into the lunar regolith to form a critical reactor assembly. The regolith would not just provide radiation shielding, but serve as neutron-reflector material as well. The reactor subunits are to be manufactured using proven and tested materials for use in radiation environments, such as uranium-dioxide fuel, stainless-steel cladding and structural support, and liquid-sodium heatpipes. The LEGO Reactor system promotes reliability, safety, and ease of manufacture and testing at the cost of an increase in launch mass per overall rated power level and a reduction in neutron economy when compared to a single-reactor system. A single unshielded LEGO Reactor subunit has an estimated mass of approximately 448 kg and provides 5 kWe using a free-piston Stirling space converter. The overall envelope for a single unit with fully extended radiator panels has a height of 8.77 m and a diameter of 0.50 m. The subunits can be placed with centerline distances of approximately 0.6 m in a hexagonal-lattice pattern to provide sufficient neutronic coupling while allowing room for heat rejection and interstitial control. A lattice of six subunits could provide sufficient power generation throughout the initial stages of establishing a lunar outpost. Portions of the reactor may be neutronically decoupled to allow for reduced power production during unmanned periods of base operations. During later stages of lunar-base development, additional subunits may be emplaced and coupled into the existing LEGO Reactor network Future improvements include advances in reactor control methods, fuel form and matrix, determination of shielding requirements, as well as power conversion and heat rejection techniques to generate an even more competitive LEGO Reactor design. Further modifications in the design could provide power generative opportunities for use on other extraterrestrial surfaces such as Mars, other moons, and asteroids.

  1. Dimensions, maximal growth sites, and optimization in the dielectric breakdown model

    Microsoft Academic Search

    Joachim Mathiesen; Mogens H. Jensen; Jan Øystein Haavig Bakke

    2008-01-01

    We study the growth of fractal clusters in the Dielectric Breakdown Model\\u000a(DBM) by means of iterated conformal mappings. In particular we investigate the\\u000afractal dimension and the maximal growth site (measured by the Hoelder exponent\\u000a$\\\\alpha_{min}$) as a function of the growth exponent $\\\\eta$ of the DBM model.\\u000aWe do not find evidence for a phase transition from fractal

  2. Optimization of growth conditions of Lentinus edodes mycelium on corn processing waste using response surface analysis.

    PubMed

    Lee, Seungyong; Bae, Hyokwan; Kim, Nakyung; Hwang, Seokhwan

    2008-02-01

    This research was conducted to evaluate the use of corn processing waste as an alternative growth medium for the cultivation of Lentinus edodes mycelium and to determine the optimum growth conditions under solid-state cultivation. The substrate concentration, pH, and temperature for maximizing the growth rate of L. edodes mycelium, 9.3+/-0.6 mm/d, were 44.3 g/l, 4.7, and 24.7 degrees C, respectively. Therefore, the results suggest that corn processing waste can be utilized as a growth substrate for cultivating L. edodes mycelium. PMID:18343345

  3. Inequality in Language Achievement Growth? An Investigation into the Impact of Pupil Socio-Ethnic Background and School Socio-Ethnic Composition

    ERIC Educational Resources Information Center

    Belfi, Barbara; Goos, Mieke; Pinxten, Maarten; Verhaeghe, Jean Pierre; Gielen, Sarah; De Fraine, Bieke; Van Damme, Jan

    2014-01-01

    This paper investigates how pupils' growth trajectories in three language domains (reading fluency, spelling, and reading comprehension) are related to their own socioeconomic and ethnic background and to the socioeconomic and ethnic composition of their primary school. Using multilevel piecewise growth curve analysis, the growth trajectories…

  4. Optimal regeneration planning for old-growth forest: addressing scientific uncertainty in endangered species recovery through adaptive management

    USGS Publications Warehouse

    Moore, C.T.; Conroy, M.J.

    2006-01-01

    Stochastic and structural uncertainties about forest dynamics present challenges in the management of ephemeral habitat conditions for endangered forest species. Maintaining critical foraging and breeding habitat for the endangered red-cockaded woodpecker (Picoides borealis) requires an uninterrupted supply of old-growth forest. We constructed and optimized a dynamic forest growth model for the Piedmont National Wildlife Refuge (Georgia, USA) with the objective of perpetuating a maximum stream of old-growth forest habitat. Our model accommodates stochastic disturbances and hardwood succession rates, and uncertainty about model structure. We produced a regeneration policy that was indexed by current forest state and by current weight of evidence among alternative model forms. We used adaptive stochastic dynamic programming, which anticipates that model probabilities, as well as forest states, may change through time, with consequent evolution of the optimal decision for any given forest state. In light of considerable uncertainty about forest dynamics, we analyzed a set of competing models incorporating extreme, but plausible, parameter values. Under any of these models, forest silviculture practices currently recommended for the creation of woodpecker habitat are suboptimal. We endorse fully adaptive approaches to the management of endangered species habitats in which predictive modeling, monitoring, and assessment are tightly linked.

  5. Ecological Optimism in the Social Sciences: The Question of Limits to Growth.

    ERIC Educational Resources Information Center

    Luten, Daniel B.

    1980-01-01

    Reviews various social science models of man designed to explain the issue of limits to growth for human societies. Presents arguments often advanced by proponents of pessimistic and optimistic schools of thought regarding whether society will be successfully able to deal with the limits to growth controversy. (Author/DB)

  6. Optimized growth of graphene on SiC: from the dynamic flip mechanism.

    PubMed

    Wang, Dandan; Liu, Lei; Chen, Wei; Chen, Xiaobo; Huang, Han; He, Jun; Feng, Yuan-Ping; Wee, A T S; Shen, D Z

    2015-02-26

    Thermal decomposition of single-crystal SiC is one of the popular methods for growing graphene. However, the mechanism of graphene formation on the SiC surface is poorly understood, and the application of this method is also hampered by its high growth temperature. In this study, based on the ab initio calculations, we propose a vacancy assisted Si-C bond flipping model for the dynamic process of graphene growth on SiC. The fact that the critical stages during growth take place at different energy costs allows us to propose an energetic-beam controlled growth method that not only significantly lowers the growth temperature but also makes it possible to grow high-quality graphene with the desired size and patterns directly on the SiC substrate. PMID:25682710

  7. Optimized growth of graphene on SiC: from the dynamic flip mechanism

    NASA Astrophysics Data System (ADS)

    Wang, Dandan; Liu, Lei; Chen, Wei; Chen, Xiaobo; Huang, Han; He, Jun; Feng, Yuan-Ping; Wee, A. T. S.; Shen, D. Z.

    2015-02-01

    Thermal decomposition of single-crystal SiC is one of the popular methods for growing graphene. However, the mechanism of graphene formation on the SiC surface is poorly understood, and the application of this method is also hampered by its high growth temperature. In this study, based on the ab initio calculations, we propose a vacancy assisted Si-C bond flipping model for the dynamic process of graphene growth on SiC. The fact that the critical stages during growth take place at different energy costs allows us to propose an energetic-beam controlled growth method that not only significantly lowers the growth temperature but also makes it possible to grow high-quality graphene with the desired size and patterns directly on the SiC substrate.

  8. Optimizing Epitaxial Cu and Ni Films on Al2O3(0001) for Uniform Graphene Growth

    NASA Astrophysics Data System (ADS)

    Miller, David L.; Keller, Mark W.; Keller, Robert R.; Shaw, Justin M.; Chiaramonti, Ann N.

    2012-02-01

    Copper and nickel are the most commonly used substrates for the growth of graphene by chemical vapor deposition. While cold-rolled polycrystalline foils are most often selected for their commercial availability and ability to withstand the high temperatures required for graphene growth, (111) crystal faces have been shown to offer better growth characteristics on both materials. We deposited Cu and Ni films onto single crystal Al2O3(0001) using magnetron sputtering at temperatures between 250 ^oC and 700 ^oC. This gave films with pure (111) texture but with two epitaxial in-plane orientations as measured by x-ray diffraction and electron backscatter diffraction. Upon heating to graphene CVD temperatures (900 ^oC to 1000 ^oC), the grain boundaries widen and deepen into trenches that prevent the growth of uniform graphene over large areas. Reactive sputtering of a thin layer of Al2O3 before depositing the metal results in a single in-plane orientation over >90% of the film for Ni. In addition, gradually increasing the temperature during metal deposition suppresses the formation of deep trenches under graphene CVD conditions. We compare CVD graphene grown on the optimized films with that grown on commercial foils.

  9. Growth

    NSDL National Science Digital Library

    Massachusetts Institute of Technology

    Introduction to models of economic growth with a great deal of focus on the Solow Growth Model both its theory and testing it with data. Also contains a discussion of the effects of the Greenspan Put. From a macroeconomics course at the the Massachusetts Institute of Technology.

  10. Engineering carbon nanostructures : development of novel aerogel-nanotube composites and optimization techniques for nanotube growth

    E-print Network

    Steiner, Stephen Alan, III

    2006-01-01

    Carbon aerogels offer several unique advantages which make them ideal for evaluating a metal's ability to catalyze nanotube growth, including in situ carbothermic reduction of oxidized nanoparticles to their catalytic ...

  11. The Effects of Middle School Bullying and Victimization on Adjustment through High School: Growth Modeling of Achievement, School Attendance, and Disciplinary Trajectories

    ERIC Educational Resources Information Center

    Feldman, Marissa A.; Ojanen, Tiina; Gesten, Ellis L.; Smith-Schrandt, Heather; Brannick, Michael; Wienke Totura, Christine M.; Alexander, Lizette; Scanga, David; Brown, Ken

    2014-01-01

    The current 5-year longitudinal study examined the effects of middle school bullying and victimization on adolescent academic achievement, disciplinary referrals, and school attendance through high school (N = 2030; 1016 both boys and girls). Greater engagement in bullying behaviors was concurrently associated with lower achievement and school…

  12. Modeling of Fusarium redolens Dzf2 mycelial growth kinetics and optimal fed-batch fermentation for beauvericin production.

    PubMed

    Xu, Li-Jian; Liu, Yuan-Shuai; Zhou, Li-Gang; Wu, Jian-Yong

    2011-09-01

    Beauvericin (BEA) is a cyclic hexadepsipeptide mycotoxin with notable phytotoxic and insecticidal activities. Fusarium redolens Dzf2 is a highly BEA-producing fungus isolated from a medicinal plant. The aim of the current study was to develop a simple and valid kinetic model for F. redolens Dzf2 mycelial growth and the optimal fed-batch operation for efficient BEA production. A modified Monod model with substrate (glucose) and product (BEA) inhibition was constructed based on the culture characteristics of F. redolens Dzf2 mycelia in a liquid medium. Model parameters were derived by simulation of the experimental data from batch culture. The model fitted closely with the experimental data over 20-50 g l(-1) glucose concentration range in batch fermentation. The kinetic model together with the stoichiometric relationships for biomass, substrate and product was applied to predict the optimal feeding scheme for fed-batch fermentation, leading to 54% higher BEA yield (299 mg l(-1)) than in the batch culture (194 mg l(-1)). The modified Monod model incorporating substrate and product inhibition was proven adequate for describing the growth kinetics of F. redolens Dzf2 mycelial culture at suitable but not excessive initial glucose levels in batch and fed-batch cultures. PMID:21082211

  13. Optimization of acidic fibroblast growth factor (FGF-1) and its delivery through a modified degradable fibrin scaffold

    NASA Astrophysics Data System (ADS)

    Pandit, Abhay Smashikant

    The aim of this investigation was to develop a degradable fibrin wound dressing that can deliver an optimized dose of acidic fibroblast growth factor (FGF-1). This aim led to three distinct phases of study. In the first phase, a structurally modified fibrin degradable scaffold was developed and tested in a rabbit ear ulcer model. A significant increase in the angiogenic and fibroblastic response with a corresponding decrease in healing time was seen in the modified fibrin-treated ulcers as compared with untreated ulcers and ulcers treated with non-modified fibrin systems. In the second phase of the study, a biochemical factor, FGF-1, was added to this scaffold. An optimal dose of 8 mug of FGF-1 was determined to be required to initiate a desired wound-healing response in a rabbit ear ulcer model, based on an enhanced angiogenic and fibroblastic response and an increased epithelialization rate. The objective of the last phase was to investigate the efficacy of a modified scaffold as a vehicle for FGF-1. In vivo testing was conducted in a full-thickness defect model in a rabbit. Improvements were seen in the angiogenic and fibroblastic responses in the FGF-1/modified fibrin treatment group and, hence, FGF-1/modified fibrin was the preferred treatment. In conclusion, the modified fibrin/FGF-1 matrix served as a suitable vehicle for the growth factor, providing a desired healing response and a desirable release rate and, thus, was determined to be an effective scaffold.

  14. Rational identification of an optimal antibody mixture for targeting the epidermal growth factor receptor

    PubMed Central

    Koefoed, Klaus; Steinaa, Lucilla; Søderberg, Josefine Nielsen; Kjær, Ida; Jacobsen, Helle Jane; Meijer, Per-Johan; Haurum, John Sørensen; Jensen, Allan; Kragh, Michael; Andersen, Peter Sejer

    2011-01-01

    The epidermal growth factor receptor (EGFR) is frequently dysregulated in human malignancies and a validated target for cancer therapy. Two monoclonal anti-EGFR antibodies (cetuximab and panitumumab) are approved for clinical use. However, the percentage of patients responding to treatment is low and many patients experiencing an initial response eventually relapse. Thus, the need for more efficacious treatments remains. Previous studies have reported that mixtures of antibodies targeting multiple distinct epitopes are more effective than single mAbs at inhibiting growth of human cancer cells in vitro and in vivo. The current work describes the rational approach that led to discovery and selection of a novel anti-EGFR antibody mixture Sym004, which is currently in Phase 2 clinical testing. Twenty-four selected anti-EGFR antibodies were systematically tested in dual and triple mixtures for their ability to inhibit cancer cells in vitro and tumor growth in vivo. The results show that targeting EGFR dependent cancer cells with mixtures of antibodies is superior at inhibiting their growth both in vitro and in vivo. In particular, antibody mixtures targeting non-overlapping epitopes on domain III are efficient and indeed Sym004 is composed of two monoclonal antibodies targeting this domain. The superior growth inhibitory activity of mixtures correlated with their ability to induce efficient EGFR degradation. PMID:22123060

  15. Analysis of Environmental Stress Factors Using an Artificial Growth System and Plant Fitness Optimization

    PubMed Central

    Lee, Meonghun; Yoe, Hyun

    2015-01-01

    The environment promotes evolution. Evolutionary processes represent environmental adaptations over long time scales; evolution of crop genomes is not inducible within the relatively short time span of a human generation. Extreme environmental conditions can accelerate evolution, but such conditions are often stress inducing and disruptive. Artificial growth systems can be used to induce and select genomic variation by changing external environmental conditions, thus, accelerating evolution. By using cloud computing and big-data analysis, we analyzed environmental stress factors for Pleurotus ostreatus by assessing, evaluating, and predicting information of the growth environment. Through the indexing of environmental stress, the growth environment can be precisely controlled and developed into a technology for improving crop quality and production.

  16. Optimization of low temperature GaN buffer layers for halide vapor phase epitaxy growth of bulk GaN

    NASA Astrophysics Data System (ADS)

    Hemmingsson, Carl; Pozina, Galia

    2013-03-01

    We have studied growth and self-separation of bulk GaN on c-oriented Al2O3 using low temperature (LT) GaN buffer layers. By studying the X-ray diffraction (XRD) signature for the asymmetric and symmetric reflections versus the LT-GaN thickness and V/III precursor ratio, we observe that the peak width of the reflections is minimized using a LT buffer thickness of ˜100-300 nm. It was observed that the V/III precursor ratio has a strong influence on the morphology. In order to obtain a smooth morphology, the V/III precursor ratio has to be more than 17 during the growth of the buffer layer. By using an optimized LT buffer layer for growth of a 20 ?m thick GaN layer, we obtain a XRD peak with a full width at half maximum of ˜400 and ˜250 arcs for (002) and (105) reflection planes, respectively, and with a dark pit density of ˜2.2×108 cm-2. For layers thicker than 1 mm, the GaN was spontaneously separated and by utilizing this process, thick free freestanding 2? GaN substrates were manufactured.

  17. Callus cultures of Artemisia absinthium L.: initiation, growth optimization and organogenesis

    Microsoft Academic Search

    Stefania Nin; Elena Morosi; Silvia Schiff I; Andrea Bennici

    1996-01-01

    Callus cultures were initiated from micropropagated Artemisia absinthium plantlets on MS basal medium supplemented with different concentrations of BA, Kn, NAA, IAA and 2,4-d in combination or singly. Supplementing the medium with low doses of both BA in combination with NAA, and Kn in combination with NAA enhanced the growth rate of callus cultures. However, cultures grew slowly following the

  18. IMPACTS OF FAMILY BUSINESSES ON ECONOMIC STABILITY AND GROWTH - AN OPTIMIZATION APPROACH

    Microsoft Academic Search

    Gottfried Haber

    Family businesses are an important factor for technological progress and high economic efficiency, determining a significant part of economic strength. At present, inside the European Monetary Union (EMU), there are efforts to reduce public debt to fulfill the criteria imposed by the Stability and Growth Pact (SGP), which are mandatory for members of the Euro zone. Due to these constraints,

  19. Long term growth responses of loblolly pine to optimal nutrient and water resource availability

    Microsoft Academic Search

    Timothy J. Albaugh; H. Lee Allen; Phillip M. Dougherty; Kurt H. Johnsen

    2004-01-01

    A factorial combination of four treatments (control (CW), optimal growing season water availability (IW), optimum nutrient availability (FW), and combined optimum water and nutrient availability (FIW)) in four replications were initiated in an 8-year-old Pinus taeda stand growing on a droughty, nutrient-poor, sandy site in Scotland County, NC and maintained for 9 years. Results for the first 4 years after

  20. Optimization of growth conditions of vapor deposited Mo\\/Si multilayers

    Microsoft Academic Search

    Mary Beth Stearns; Chung-Hee Chang; Daniel G. Stearns

    1992-01-01

    The dependence of the layer structure and interfaces of e-beam deposited Mo\\/Si multilayers (ML) on growth conditions has been studied. The substrate temperature was varied over a range of 300–600 K at deposition rates of 1 and 3 A?\\/s. The structure of the ML was determined using small-angle x-ray scattering, large-angle x-ray scattering, and cross-sectional high-resolution electron microscopy. The variation

  1. Optimization of growth conditions of vapor deposited Mo\\/Si multilayers

    Microsoft Academic Search

    Mary Beth Stearns; Chung-Hee Chang; Daniel G. Stearns

    1992-01-01

    The dependence of the layer structure and interfaces of {ital e}-beam deposited Mo\\/Si multilayers (ML) on growth conditions has been studied. The substrate temperature was varied over a range of 300--600 K at deposition rates of 1 and 3 A\\/s. The structure of the ML was determined using small-angle x-ray scattering, large-angle x-ray scattering, and cross-sectional high-resolution electron microscopy. The

  2. Optimization of plant mineral nutrition under growth-limiting conditions in a lunar greenhouse

    NASA Astrophysics Data System (ADS)

    Zaets, I.; Voznyuk, T.; Kovalchuk, M.; Rogutskyy, I.; Lukashov, D.; Mytrokhyn, O.; Mashkovska, S.; Foing, B.; Kozyrovska, N.

    It may be assumed that the first plants in a lunar base will play a main role in forming a protosoil of acceptable fertility needed for purposively growing second generation plants like wheat, rice, tulips, etc. The residues of the first-generation plants could be composted and transformed by microorganisms into a soil-like substrate within a loop of regenerative life support system. The lunar regolith may be used as a substrate for plant growth at the very beginning of a mission to reduce its cost. The use of microbial communities for priming plants will allow one to facilitate adaption to stressful conditions and to support the plant development under growth limiting conditions. Well-defined plant-associated bacteria were used for growing three cultivars to colonize French marigold (Tagetes patula L.) in anorthosite, a substrate of low bioavailability, analogous to a lunar rock. The consortium was composed of plant growth promoting rhizobacteria and the bacterium Paenibacillus sp. IMBG156 which stimulated seed germination, better plant development, and finally, the flowering of inoculated tagetes. In contrast, control plants grew poorly in the anorthosite and practically did not survive until flowering. Analysis of bacterial community composition showed that all species colonized plant roots, however, the rate of colonization depended on the allelopatic characteristics of marigold varieties. Bacteria of consortium were able to liberate some elements (Ca, Fe, Mn, Si, Ni, Cu, Zn) from substrate anorthosite. Plant colonization by mixed culture of bacterial strains resulted in the increase of accumulation of K, Mg, Mn by the plant and in the lowering of the level of toxic metal accumulation. It was assumed that a rationally assembled consortium of bacterial strains promoted germination of marygold seeds and supported the plant development under growth limiting conditions by means of bioleaching plant essential nutritional elements and by protecting the plant against hyperaccumulation of some toxic metals.

  3. Physiological studies on microalgal culture additives to optimize growth rate and oil content.

    PubMed

    Gomaa, Ahmed E; Hafez, E E; Lim, Hyun Soo; Chung, Gyu Hwa; Sun, Sang Mi

    2012-01-01

    Insulin, in nature, has a stimulatory effect on microorganisms. These effects include the acceleration of sugar metabolism, triacylglycerol anabolism, growth rate, and formation of oils. We also observed that insulin may cause indirect activation of triacylglycerol lipase by forcing the cell to permanently require an energy source. Thus, cells can consume all of their accumulated internal fuel sources such as lipids, proteins, and carbohydrates. After studying the effects of using two types of insulin (Humulin 70/30, and human insulin expressed in yeast) at different concentrations on microalgae (Chlorella sp.), we found that with certain concentrations of insulin (1:3.3 ml unit Humulin 70/30 per ml; 1:2.6 ml unit yeast insulin per ml), there was an increase in algal growth rate and decrease in cell size. We therefore studied the effect of insulin under conditions of lipase inhibition by Triton WR 1339 (Tyloxapol), which was used at different concentrations with and without insulin. We found strong regression in the growth rate with increasing Triton concentrations. However, we also observed that the cell size under the effect of Triton and Triton-insulin was larger than the cell size under the effect of insulin alone, and also larger than for control cells. Also, the oil content of the Triton-insulin cells was higher than those of the control cells or the cells under the effect of insulin alone. PMID:21947703

  4. Optimization of peptides that target human thymidylate synthase to inhibit ovarian cancer cell growth.

    PubMed

    Pelà, Michela; Saxena, Puneet; Luciani, Rosaria; Santucci, Matteo; Ferrari, Stefania; Marverti, Gaetano; Marraccini, Chiara; Martello, Andrea; Pirondi, Silvia; Genovese, Filippo; Salvadori, Severo; D'Arca, Domenico; Ponterini, Glauco; Costi, Maria Paola; Guerrini, Remo

    2014-02-27

    Thymidylate synthase (TS) is a target for pemetrexed and the prodrug 5-fluorouracil (5-FU) that inhibit the protein by binding at its active site. Prolonged administration of these drugs causes TS overexpression, leading to drug resistance. The peptide lead, LR (LSCQLYQR), allosterically stabilizes the inactive form of the protein and inhibits ovarian cancer (OC) cell growth with stable TS and decreased dihydrofolate reductase (DHFR) expression. To improve TS inhibition and the anticancer effect, we have developed 35 peptides by modifying the lead. The d-glutamine-modified peptide displayed the best inhibition of cisplatin-sensitive and -resistant OC cell growth, was more active than LR and 5-FU, and showed a TS/DHFR expression pattern similar to LR. Circular dichroism spectroscopy and molecular dynamics studies provided a molecular-level rationale for the differences in structural preferences and the enzyme inhibitory activities. By combining target inhibition studies and the modulation pattern of associated proteins, this work avenues a concept to develop more specific inhibitors of OC cell growth and drug leads. PMID:24450514

  5. Development of a coupled model of a distributed hydrological model and a rice growth model for optimizing irrigation schedule

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Kumiko; Homma, Koki; Koike, Toshio; Ohta, Tetsu

    2013-04-01

    A coupled model of a distributed hydrological model and a rice growth model was developed in this study. The distributed hydrological model used in this study is the Water and Energy Budget-based Distributed Hydrological Model (WEB-DHM) developed by Wang et al. (2009). This model includes a modified SiB2 (Simple Biosphere Model, Sellers et al., 1996) and the Geomorphology-Based Hydrological Model (GBHM) and thus it can physically calculate both water and energy fluxes. The rice growth model used in this study is the Simulation Model for Rice-Weather relations (SIMRIW) - rainfed developed by Homma et al. (2009). This is an updated version of the original SIMRIW (Horie et al., 1987) and can calculate rice growth by considering the yield reduction due to water stress. The purpose of the coupling is the integration of hydrology and crop science to develop a tool to support decision making 1) for determining the necessary agricultural water resources and 2) for allocating limited water resources to various sectors. The efficient water use and optimal water allocation in the agricultural sector are necessary to balance supply and demand of limited water resources. In addition, variations in available soil moisture are the main reasons of variations in rice yield. In our model, soil moisture and the Leaf Area Index (LAI) are calculated inside SIMRIW-rainfed so that these variables can be simulated dynamically and more precisely based on the rice than the more general calculations is the original WEB-DHM. At the same time by coupling SIMRIW-rainfed with WEB-DHM, lateral flow of soil water, increases in soil moisture and reduction of river discharge due to the irrigation, and its effects on the rice growth can be calculated. Agricultural information such as planting date, rice cultivar, fertilization amount are given in a fully distributed manner. The coupled model was validated using LAI and soil moisture in a small basin in western Cambodia (Sangker River Basin). This basin is mostly rainfed paddy so that irrigation scheme was firstly switched off. Several simulations with varying irrigation scheme were performed to determine the optimal irrigation schedule in this basin.

  6. Optimization of MW-PACVD diamond deposition parameters for high nucleation density and growth rate on Si 3N 4 substrate

    Microsoft Academic Search

    H. Buchkremer-Hermanns; H. Ren; J. Utsch; H. Weiss

    1997-01-01

    We use orthogonal designs of experiments to optimize the process parameters for high diamond nucleation density and growth rate. The diamond films were deposited on Si3N4 substrate in a MW-PACVD reactor with a gas mixture of methane and hydrogen. The process pressure, the substrate temperature, the total gas flow and the methane concentration were varied in selected ranges. The optimal

  7. Optimization of self-coherent reflective PON to achieve a new record 42 dB ODN power budget after 100 km at 1.25 Gbps.

    PubMed

    Straullu, S; Forghieri, F; Ferrero, V; Gaudino, R

    2012-12-31

    We demonstrate a greater than 42 dB optical distribution network power budget in the upstream of a 1.25 Gbps self-coherent reflective PON after 100 km of installed fibers, using off-the-shelf optoelectronic components, improving our previous result by 4 dB. We discuss all system optimizations introduced in the setup in order to reach such a result, including 8B/10B high-pass filtering and Faraday rotation at the ONU. PMID:23388785

  8. High-Performance n-type Organic Semiconductors: Incorporating Specific Electron-Withdrawing Motifs to Achieve Tight Molecular Stacking and Optimized Energy Levels

    SciTech Connect

    Park S. Y.; Yang L.; Yun, S.W.; Kim, J.H.; Shin, S.; Yang, H.; An B.

    2012-01-16

    Novel {pi}-conjugated cyanostilbene-based semiconductors (Hex-3,5-TFPTA and Hex-4-TFPTA) with tight molecular stacking and optimized energy levels are synthesized. Hex-4-TFPTA exhibits high-performance n-type organic field-effect transistor (OFET) properties with electron mobilities as high as 2.14 cm{sup 2} V{sup -1}s{sup -1} and on-off current ratios >10{sup 6}.

  9. OPTIMIZATION OPTIMIZATION

    E-print Network

    Stanford University

    CONVEX OPTIMIZATION & EUCLIDEAN DISTANCE GEOMETRY DATTORRO M #12;Dattorro CONVEX OPTIMIZATION & EUCLIDEAN DISTANCE GEOMETRY Meboo #12;Convex Optimization & Euclidean Distance Geometry Jon Dattorro Moo & Euclidean Distance Geometry, Moo, 2005, v2014.04.08. ISBN 0976401304 (English) ISBN 9780615193687

  10. Computational Model Identifies Optimal Combinations of Targeted Therapeutics | Physical Sciences in Oncology

    Cancer.gov

    As cancer researchers continue to develop powerful targeted therapeutics, it is becoming clear that these newer agents will need to be used in combination with one another to achieve optimal, long-lasting effects on tumor growth.

  11. Optimizing the osteogenic differentiation of human mesenchymal stromal cells by the synergistic action of growth factors.

    PubMed

    Açil, Yahya; Ghoniem, Amir-Alexander; Wiltfang, Jörg; Gierloff, Matthias

    2014-12-01

    A variety of different growth factors, most notably bone morphogenetic proteins (BMPs), have been shown to stimulate the osteogenic differentiation of mesenchymal stromal cells (MSCs) in vitro. Yet, due to the lack of comparative studies it remains unclear which protocol is the most effective in the induction of osteogenesis in MSC cultures. The aim of this study was to compare the most potent growth factors in regard to their osteoinductive potential. Human MSCs were cultured for 10 days in the presence of BMP-2, BMP-6, BMP-9 + IGF-2 and BMP-2, -6, -9 (day 1 + 2: 50 ng/ml; days 3-6: 100 ng/ml; days 7-10: 200 ng/ml). The formation of the osteoblast phenotype was assessed by quantification of osteoblast-related marker genes using reverse transcription polymerase chain reaction (RT-PCR) and alkaline phosphatase (ALP) staining. Matrix mineralization was assessed by alizarin red S and von Kossa staining. Statistical analysis was carried out using the one-way analysis of variance (ANOVA) followed by Scheffe's post hoc procedure. Among the tested growth factors the combination of BMP-2 + BMP-6 + BMP-9 most effectively induced the upregulation of collagen type I, collagen type V, osteocalcin, alkaline phosphatase, RUNX2, BMP-2, osteonectin and DLX5 (p < 0.01) and resulted in a consistent matrix mineralization. The findings suggest the combined addition of BMP-2, BMP-6 and BMP-9 to the osteoinductive culture medium containing dexamethasone, ?-glycerophosphate and ascorbate-2-phosphate produces more potent osteoblast differentiation of human MSCs in vitro. PMID:25458345

  12. New and Expanded Concepts in Neurophysiology, Psychology, and Sociology Complementary to Llorens' Developmental Theory: Achieving Growth and Development through Occupation for Neonatal Infants and their Families

    Microsoft Academic Search

    Lynne F. La Corte

    2008-01-01

    Introduction: This issue expands the Llorens’ Developmental Theory of Occupational Therapy. Llorens drew from multiple theorists from the disciplines of sociology, neurophysiology, biology, ecology, psychology, occupational science, and psychodynamics to provide the profession of occupational therapy with a unified theory to facilitate growth and development for people of all ages—from infancy to old age.Purpose: The purpose of this issue is

  13. Reading Achievement across Three Language Groups: Growth Estimates for Overall Reading and Reading Subskills Obtained with the Early Childhood Longitudinal Survey

    ERIC Educational Resources Information Center

    Roberts, Greg; Mohammed, Sarojani S.; Vaughn, Sharon

    2010-01-01

    This study estimated normative reading trajectories for the population of English-proficient language minority students attending U.S. public elementary schools. Achievement of English-language learners (ELLs) was evaluated in terms of native English speakers' progress, and estimates were adjusted for the effects of socioeconomic status (SES). The…

  14. Linking Student Achievement Growth to Professional Development Participation and Changes in Instruction: A Longitudinal Study of Elementary Students and Teachers in Title I Schools

    ERIC Educational Resources Information Center

    Desimone, Laura; Smith, Thomas M.; Phillips, Kristie J. R.

    2013-01-01

    Background/Context: Most reforms in elementary education rely on teacher learning and improved instruction to increase student learning. This study increases our understanding of which types of professional development effectively change teaching practice in ways that boost student achievement. Purpose/Objective/Research Question/Focus of Study:…

  15. Family and Contextual Socioeconomic Effects across Seasons: When Do They Matter for the Achievement Growth of Young Children? WCER Working Paper No. 2007-5, August 2007

    ERIC Educational Resources Information Center

    Benson, James G.; Borman, Geoffrey D.

    2007-01-01

    Researchers have disagreed about the extent to which differences in achievement based on socioeconomic status (SES) accumulate during the school year as compared to the summer, and the literature has not fully assessed the contributions of social contexts--in the form of both school and neighborhood poverty concentration and racial and ethnic…

  16. Studies on growth kinetics of Serratia marcescens VITSD2 and optimization of fermentation conditions for serratiopeptidase production.

    PubMed

    Subathra, Devi C; Alam, Shah; Nag, Suraj Kumar; Jemimah, Naine S; Mohanasrinivasan, V; Vaishnavi, B

    2014-01-01

    Serratia is one of the most important groups of bacteria which produces proteolytic enzymes effectively and known to possess anti- inflammatory properties. The main focus of the current study was to optimize the culture conditions of Serratia marcescens VITSD2 for the mass production of serratiopeptidase. Effect of various nutritional and environmental factors were analysed and optimized. Among the different carbon and nitrogen sources tested, mannose and soya bean meal was found to be the best with enzyme activity of 1391 units /mL and 1800 U/mL respectively. The enzyme showed an optimum activity of 1668 U/mL at pH-8 and 1500 U/mL at 25ºC. Maximum peptidase production during fermentation was obtained after 24 h incubation with 1% inoculum in the medium at 25ºC and yielded 1668 U/mL. Lysine stimulated the production of peptidase and the yield obtained was 2410U/mL. Growth curve analysis was done. Maximum serratiopeptidase production was detected after 24 h incubation with 2155 units/mL and cell density of 2.4g/100mL. Hence the observation of the present study clearly indicates that the yield of Serratiopeptidase was found to be maximum by varying the cultural conditions. PMID:25056366

  17. Increasing costs due to ocean acidification drives phytoplankton to be more heavily calcified: optimal growth strategy of coccolithophores.

    PubMed

    Irie, Takahiro; Bessho, Kazuhiro; Findlay, Helen S; Calosi, Piero

    2010-01-01

    Ocean acidification is potentially one of the greatest threats to marine ecosystems and global carbon cycling. Amongst calcifying organisms, coccolithophores have received special attention because their calcite precipitation plays a significant role in alkalinity flux to the deep ocean (i.e., inorganic carbon pump). Currently, empirical effort is devoted to evaluating the plastic responses to acidification, but evolutionary considerations are missing from this approach. We thus constructed an optimality model to evaluate the evolutionary response of coccolithophorid life history, assuming that their exoskeleton (coccolith) serves to reduce the instantaneous mortality rates. Our model predicted that natural selection favors constructing more heavily calcified exoskeleton in response to increased acidification-driven costs. This counter-intuitive response occurs because the fitness benefit of choosing a better-defended, slower growth strategy in more acidic conditions, outweighs that of accelerating the cell cycle, as this occurs by producing less calcified exoskeleton. Contrary to the widely held belief, the evolutionarily optimized population can precipitate larger amounts of CaCO(3) during the bloom in more acidified seawater, depending on parameter values. These findings suggest that ocean acidification may enhance the calcification rates of marine organisms as an adaptive response, possibly accompanied by higher carbon fixation ability. Our theory also provides a compelling explanation for the multispecific fossil time-series record from ?200 years ago to present, in which mean coccolith size has increased along with rising atmospheric CO(2) concentration. PMID:20976167

  18. Optimization of potent DFG-in inhibitors of platelet derived growth factor receptor? (PDGF-R?) guided by water thermodynamics.

    PubMed

    Horbert, Rebecca; Pinchuk, Boris; Johannes, Eugen; Schlosser, Joachim; Schmidt, Dorian; Cappel, Daniel; Totzke, Frank; Schächtele, Christoph; Peifer, Christian

    2015-01-01

    In this study we report on the hit optimization of substituted 3,5-diaryl-pyrazin-2(1H)-ones toward potent and effective platelet-derived growth factor receptor (PDGF-R) ?-inhibitors. Originally, the 3,5-diaryl-pyrazin-2-one core was derived from the marine sponge alkaloid family of hamacanthins. In our first series compound 2 was discovered as a promising hit showing strong activity against PDGF-R? in the kinase assay (IC50 = 0.5 ?M). Furthermore, 2 was shown to be selective for PDGF-R? in a panel of 24 therapeutically relevant protein kinases. Molecular modeling studies on a PDGF-R? homology model using prediction of water thermodynamics suggested an optimization strategy for the 3,5-diaryl-pyrazin-2-ones as DFG-in binders by using a phenolic OH function to replace a structural water molecule in the ATP binding site. Indeed, we identified compound 38 as a highly potent inhibitor with an IC50 value of 0.02 ?M in a PDGF-R? enzymatic assay also showing activity against PDGF-R dependent cancer cells. PMID:25007344

  19. Method for polyhedral approximation of a ball with an optimal order of growth of the facet structure cardinality

    NASA Astrophysics Data System (ADS)

    Kamenev, G. K.

    2014-08-01

    The problem of polyhedral approximation of a multidimensional ball is considered. It is well known that the norm of the f-vector (the maximum number of faces of all dimensions) of an approximating polytope grows at least as fast as O(?(1 - d)/2), where ? is the Hausdorff deviation and d is the space dimension. An iterative method, namely, the deep holes method is used to construct metric nets. As applied to the problem under study, the method sequentially supplements the vertex set of the polytope with its deep holes in the metric on the ball surface (i.e., with points of the surface that are farthest away from the vertices of the polytope). It is shown that the facet structure cardinality of the constructed polytope has an optimal growth rate. It is also shown that the number of faces of all dimensions in the approximating polytopes generated by the method is asymptotically proportional to the number of their vertices. Closed-form expressions for the constants are obtained, which depend only on the dimension of the space, including the case of high dimensions. For low dimensions ( d ranging from 3 to 5), upper bounds for the growth rate of the number of faces of all dimensions are obtained depending on the accuracy of the approximation.

  20. Complementary Feeding: Critical Considerations to Optimize Growth, Nutrition, and Feeding Behavior.

    PubMed

    Young, Bridget E; Krebs, Nancy F

    2013-12-01

    This review focuses on complementary feeding (CF) in westernized settings where primary health concerns are risk of obesity and micronutrient inadequacy. The current evidence is reviewed for: (1) when CF should be introduced, (2) what foods (nutrients and food types) should be prioritized and avoided, and (3) how the infant should be fed. Special attention is paid to the underlying physiological differences between breast- and formula-fed infants that often result in distinctly different nutritional and health risks. This difference is particularly acute in the case of micronutrient inadequacy, specifically iron and zinc, but is also relevant to optimal energy and macronutrient intakes. Emphasis is placed on the complex interplay among infants' early dietary exposures; relatively high energy and nutrient requirements; rapid physical, social and emotional development; and the feeding environment-all of which interact to impact health outcomes. This complexity needs to be considered at both individual and population levels and in both clinical and research settings. PMID:25105082

  1. Effect of Optimal Daily Fertigation on Migration of Water and Salt in Soil, Root Growth and Fruit Yield of Cucumber (Cucumis sativus L.) in Solar-Greenhouse

    PubMed Central

    Liang, Xinshu; Gao, Yinan; Zhang, Xiaoying; Tian, Yongqiang; Zhang, Zhenxian; Gao, Lihong

    2014-01-01

    Inappropriate and excessive irrigation and fertilization have led to the predominant decline of crop yields, and water and fertilizer use efficiency in intensive vegetable production systems in China. For many vegetables, fertigation can be applied daily according to the actual water and nutrient requirement of crops. A greenhouse study was therefore conducted to investigate the effect of daily fertigation on migration of water and salt in soil, and root growth and fruit yield of cucumber. The treatments included conventional interval fertigation, optimal interval fertigation and optimal daily fertigation. Generally, although soil under the treatment optimal interval fertigation received much lower fertilizers than soil under conventional interval fertigation, the treatment optimal interval fertigation did not statistically decrease the economic yield and fruit nutrition quality of cucumber when compare to conventional interval fertigation. In addition, the treatment optimal interval fertigation effectively avoided inorganic nitrogen accumulation in soil and significantly (P<0.05) increased the partial factor productivity of applied nitrogen by 88% and 209% in the early-spring and autumn-winter seasons, respectively, when compared to conventional interval fertigation. Although soils under the treatments optimal interval fertigation and optimal daily fertigation received the same amount of fertilizers, the treatment optimal daily fertigation maintained the relatively stable water, electrical conductivity and mineral nitrogen levels in surface soils, promoted fine root (<1.5 mm diameter) growth of cucumber, and eventually increased cucumber economic yield by 6.2% and 8.3% and partial factor productivity of applied nitrogen by 55% and 75% in the early-spring and autumn-winter seasons, respectively, when compared to the treatment optimal interval fertigation. These results suggested that optimal daily fertigation is a beneficial practice for improving crop yield and the water and fertilizers use efficiency in solar greenhouse. PMID:24475204

  2. Microbial-enzymatic-hybrid biological fuel cell with optimized growth conditions for Shewanella oneidensis DSP-10.

    PubMed

    Roy, Jared N; Luckarift, Heather R; Sizemore, Susan R; Farrington, Karen E; Lau, Carolin; Johnson, Glenn R; Atanassov, Plamen

    2013-07-10

    In this work we present a biological fuel cell fabricated by combining a Shewanella oneidensis microbial anode and a laccase-modified air-breathing cathode. This concept is devised as an extension to traditional biochemical methods by incorporating diverse biological catalysts with the aim of powering small devices. In preparing the biological fuel cell anode, novel hierarchical-structured architectures and biofilm configurations were investigated. A method for creating an artificial biofilm based on encapsulating microorganisms in a porous, thin film of silica was compared with S. oneidensis biofilms that were allowed to colonize naturally. Results indicate comparable current and power densities for artificial and natural biofilm formations, based on growth characteristics. As a result, this work describes methods for creating controllable and reproducible bio-anodes and demonstrates the versatility of hybrid biological fuel cells. PMID:23769313

  3. Optimized pyroelectric vidicon thermal imager. Volume 2: Improper perroelectric crystal growth

    NASA Astrophysics Data System (ADS)

    Smith, W. A.; Loiacono, G.; Shaulov, A.

    1980-09-01

    Complete dielectric, pyroelectric, and thermal characterizations of Fe3B7O13I, Cu3B7O13C1 and Mn3B7O13I were performed to confirm the expectation that the boracite family of improper ferroelectrics exhibits high pyroelectric open-circuit voltage response. In each of these materials, the figure of merit, p/epsilon c, rises as the transition temperature is approached; the peak value attained at the transition varies only slightly in a temperature interval of several degrees below the transition. The peak figures-of-merit of these materials are larger than that of TGS and close to that of DTGFB (FeI: 6,000 sq. cm/c; CuCl: 6,000 sq. cm/c; MnI: 5,300 sq cm/c). A vapor-transport growth technique was developed which can produce boracite single crystals of sufficient size for device applications. Complete dielectric, pyroelectric, and thermal characterizations of the dicalcium lead propionate (DLP) Ca2Pb(C2H5COO)6 and dicalcium strontium propionate (DSP) family of pseudo-proper ferroelectrics exhibits a high, broad maximum in their figures of merit. The measured figures-of-merit are larger than that of TGS and close to that of DTGFB (DLP: 5,000 sq. cm/c; DSP: 5,700 sq cm/c). A solution growth technique was developed which has produced single crystals of size and quality already adequate for device application.

  4. Tumor Growth Rate Determines the Timing of Optimal Chronomodulated Treatment Schedules

    PubMed Central

    Bernard, Samuel; ?ajavec Bernard, Branka; Lévi, Francis; Herzel, Hanspeter

    2010-01-01

    In host and cancer tissues, drug metabolism and susceptibility to drugs vary in a circadian (24 h) manner. In particular, the efficacy of a cell cycle specific (CCS) cytotoxic agent is affected by the daily modulation of cell cycle activity in the target tissues. Anti-cancer chronotherapy, in which treatments are administered at a particular time each day, aims at exploiting these biological rhythms to reduce toxicity and improve efficacy of the treatment. The circadian status, which is the timing of physiological and behavioral activity relative to daily environmental cues, largely determines the best timing of treatments. However, the influence of variations in tumor kinetics has not been considered in determining appropriate treatment schedules. We used a simple model for cell populations under chronomodulated treatment to identify which biological parameters are important for the successful design of a chronotherapy strategy. We show that the duration of the phase of the cell cycle targeted by the treatment and the cell proliferation rate are crucial in determining the best times to administer CCS drugs. Thus, optimal treatment times depend not only on the circadian status of the patient but also on the cell cycle kinetics of the tumor. Then, we developed a theoretical analysis of treatment outcome (TATO) to relate the circadian status and cell cycle kinetic parameters to the treatment outcomes. We show that the best and the worst CCS drug administration schedules are those with 24 h intervals, implying that 24 h chronomodulated treatments can be ineffective or even harmful if administered at wrong circadian times. We show that for certain tumors, administration times at intervals different from 24 h may reduce these risks without compromising overall efficacy. PMID:20333244

  5. In vitro and in vivo evaluation of a novel collagen/cellulose nanocrystals scaffold for achieving the sustained release of basic fibroblast growth factor.

    PubMed

    Li, Weichang; Lan, Yong; Guo, Rui; Zhang, Yi; Xue, Wei; Zhang, Yuanming

    2015-01-01

    Tissue-engineered dermis is thought to be the best treatment for skin defects; however, slow vascularization of these biomaterial scaffolds limits their clinical application. Exogenous administration of angiogenic growth factors is highly desirable for tissue regeneration. In this study, biodegradable gelatin microspheres (GMs) containing basic fibroblast growth factor (bFGF) were fabricated and incorporated into a porous collagen/cellulose nanocrystals (CNCs) scaffold, as a platform for long-term release and consequent angiogenic boosting. The physicochemical properties of these scaffolds were examined and the in vitro release pattern of bFGF from scaffolds was measured by ELISA. Collagen/CNCs scaffolds with and without bFGF-GMs were incubated with human umbilical vein endothelial cells for 1 week, results showed that the scaffolds with bFGF-GMs significantly augmented cell proliferation. Then, four different groups of scaffolds were implanted subcutaneously into Sprague-Dawley rats to study angiogenesis in vivo via macroscopic observation, and hematoxylin and eosin and immunohistochemical staining. The results suggested that the collagen/CNCs/bFGF-GMs scaffolds had a significantly higher number of newly formed and mature blood vessels, and the fastest degradation rate. This study demonstrated that collagen/CNCs/bFGF-GMs scaffolds have great potential in skin tissue engineering. PMID:25114196

  6. The content of African diets is adequate to achieve optimal efficacy with fixed-dose artemether-lumefantrine: a review of the evidence

    PubMed Central

    Premji, Zulfiqarali G; Abdulla, Salim; Ogutu, Bernhards; Ndong, Alice; Falade, Catherine O; Sagara, Issaka; Mulure, Nathan; Nwaiwu, Obiyo; Kokwaro, Gilbert

    2008-01-01

    A fixed-dose combination of artemether-lumefantrine (AL, Coartem®) has shown high efficacy, good tolerability and cost-effectiveness in adults and children with uncomplicated malaria caused by Plasmodium falciparum. Lumefantrine bioavailability is enhanced by food, particularly fat. As the fat content of sub-Saharan African meals is approximately a third that of Western countries, it raises the question of whether fat consumption by African patients is sufficient for good efficacy. Data from healthy volunteers have indicated that drinking 36 mL soya milk (containing only 1.2 g of fat) results in 90% of the lumefantrine absorption obtained with 500 mL milk (16 g fat). African diets are typically based on a carbohydrate staple (starchy root vegetables, fruit [plantain] or cereals) supplemented by soups, relishes and sauces derived from vegetables, pulses, nuts or fish. The most important sources of dietary fat in African countries are oil crops (e.g. peanuts, soya beans) and cooking oils as red palm, peanut, coconut and sesame oils. Total fat intake in the majority of subSaharan countries is estimated to be in the range 30–60 g/person/day across the whole population (average 43 g/person/day). Breast-feeding of infants up to two years of age is standard, with one study estimating a fat intake of 15–30 g fat/day from breast milk up to the age of 18 months. Weaning foods typically contain low levels of fat, and the transition from breast milk to complete weaning is associated with a marked reduction in dietary fat. Nevertheless, fat intake >10 g/day has been reported in young children post-weaning. A randomized trial in Uganda reported no difference in the efficacy of AL between patients receiving supervised meals with a fixed fat content (~23 g fat) or taking AL unsupervised, suggesting that fat intake at home was sufficient for optimal efficacy. Moreover, randomized trials in African children aged 5–59 months have shown similar high cure rates to those observed in older populations, indicating that food consumption is adequate post-weaning. In conclusion, it appears that only a very small amount of dietary fat is necessary to ensure optimal efficacy with AL and that the fat content of standard meals or breast milk in sub-Saharan Africa is adequate. PMID:19032767

  7. The content of African diets is adequate to achieve optimal efficacy with fixed-dose artemether-lumefantrine: a review of the evidence.

    PubMed

    Premji, Zulfiqarali G; Abdulla, Salim; Ogutu, Bernhards; Ndong, Alice; Falade, Catherine O; Sagara, Issaka; Mulure, Nathan; Nwaiwu, Obiyo; Kokwaro, Gilbert

    2008-01-01

    A fixed-dose combination of artemether-lumefantrine (AL, Coartem(R)) has shown high efficacy, good tolerability and cost-effectiveness in adults and children with uncomplicated malaria caused by Plasmodium falciparum. Lumefantrine bioavailability is enhanced by food, particularly fat.As the fat content of sub-Saharan African meals is approximately a third that of Western countries, it raises the question of whether fat consumption by African patients is sufficient for good efficacy. Data from healthy volunteers have indicated that drinking 36 mL soya milk (containing only 1.2 g of fat) results in 90% of the lumefantrine absorption obtained with 500 mL milk (16 g fat). African diets are typically based on a carbohydrate staple (starchy root vegetables, fruit [plantain] or cereals) supplemented by soups, relishes and sauces derived from vegetables, pulses, nuts or fish. The most important sources of dietary fat in African countries are oil crops (e.g. peanuts, soya beans) and cooking oils as red palm, peanut, coconut and sesame oils. Total fat intake in the majority of subSaharan countries is estimated to be in the range 30-60 g/person/day across the whole population (average 43 g/person/day). Breast-feeding of infants up to two years of age is standard, with one study estimating a fat intake of 15-30 g fat/day from breast milk up to the age of 18 months. Weaning foods typically contain low levels of fat, and the transition from breast milk to complete weaning is associated with a marked reduction in dietary fat. Nevertheless, fat intake >10 g/day has been reported in young children post-weaning. A randomized trial in Uganda reported no difference in the efficacy of AL between patients receiving supervised meals with a fixed fat content (~23 g fat) or taking AL unsupervised, suggesting that fat intake at home was sufficient for optimal efficacy. Moreover, randomized trials in African children aged 5-59 months have shown similar high cure rates to those observed in older populations, indicating that food consumption is adequate post-weaning. In conclusion, it appears that only a very small amount of dietary fat is necessary to ensure optimal efficacy with AL and that the fat content of standard meals or breast milk in sub-Saharan Africa is adequate. PMID:19032767

  8. Elemental Economy: microbial strategies for optimizing growth in the face of nutrient limitation

    PubMed Central

    Merchant, Sabeeha S.; Helmann, John D.

    2014-01-01

    Microorganisms play a dominant role in the biogeochemical cycling of nutrients. They are rightly praised for their facility at fixing both carbon and nitrogen into organic matter, and microbial driven processes have tangibly altered the chemical composition of the biosphere and its surrounding atmosphere. Despite their prodigious capacity for molecular transformations, microorganisms are powerless in the face of the immutability of the elements. Limitations for specific elements, either fleeting or persisting over eons, have left an indelible trace on microbial genomes, physiology, and their very atomic composition. We here review the impact of elemental limitation on microbes, with a focus on selected genetic model systems and representative microbes from the ocean ecosystem. Evolutionary adaptations that enhance growth in the face of persistent or recurrent elemental limitations are evident from genome and proteome analyses. These range from the extreme (such as dispensing with a requirement for a hard to obtain element) to the extremely subtle (changes in protein amino acid sequences that slightly, but significantly, reduce cellular carbon, nitrogen, or sulfur demand). One near universal adaptation is the development of sophisticated acclimation programs by which cells adjust their chemical composition in response to a changing environment. When specific elements become limiting, acclimation typically begins with an increased commitment to acquisition and a concomitant mobilization of stored resources. If elemental limitation persists, the cell implements austerity measures including elemental-sparing and elemental-recycling. Insights into these fundamental cellular properties have emerged from studies at many different levels; including ecology, biological oceanography, biogeochemistry, molecular genetics, genomics, and microbial physiology. Here, we present a synthesis of these diverse studies and attempt to discern some overarching themes. PMID:22633059

  9. Sharing Leadership Responsibilities Results in Achievement Gains

    ERIC Educational Resources Information Center

    Armistead, Lew

    2010-01-01

    Collective, not individual, leadership in schools has a greater impact on student achievement; when principals and teachers share leadership responsibilities, student achievement is higher; and schools having high student achievement also display a vision for student achievement and teacher growth. Those are just a few of the insights into school…

  10. Statistical optimization of the growth factors for Chaetoceros neogracile using fractional factorial design and central composite design.

    PubMed

    Jeong, Sung-Eun; Park, Jae-Kweon; Kim, Jeong-Dong; Chang, In-Jeong; Hong, Seong-Joo; Kang, Sung-Ho; Lee, Choul-Gyun

    2008-12-01

    Statistical experimental designs; involving (i) a fractional factorial design (FFD) and (ii) a central composite design (CCD) were applied to optimize the culture medium constituents for production of a unique antifreeze protein by the Antartic microalgae Chaetoceros neogracile. The results of the FFD suggested that NaCl, KCl, MgCl2, and Na2SiO3 were significant variables that highly influenced the growth rate and biomass production. The optimum culture medium for the production of an antifreeze protein from C. neogracile was found to be Kalleampersandrsquor;s artificial seawater, pH of 7.0ampersandplusmn;0.5, consisting of 28.566 g/l of NaCl, 3.887 g/l of MgCl2, 1.787 g/l of MgSO4, 1.308 g/l of CaSO4, 0.832 g/l of K2SO4, 0.124 g/l of CaCO3, 0.103 g/l of KBr, 0.0288 g/l of SrSO4, and 0.0282 g/l of H3BO3. The antifreeze activity significantly increased after cells were treated with cold shock (at -5oC) for 14 h. To the best of our knowledge, this is the first report demonstrating an antifreeze-like protein of C. neogracile. PMID:19131694

  11. Dyar's Rule and the Investment Principle: optimal moulting strategies if feeding rate is size-dependent and growth is discontinuous

    PubMed Central

    Hutchinson, J. M. C.; McNamara, J. M.; Houston, A. I.; Vollrath, F.

    1997-01-01

    We consider animals whose feeding rate depends on the size of structures that grow only by moulting (e.g. spiders' legs). Our Investment Principle predicts optimum size increases at each moult; under simplifying assumptions these are a function of the scaling of feeding rate with size, the efficiency of moulting and the optimum size increase at the preceding moult. We show how to test this quantitatively, and make the qualitative prediction that size increases and instar durations change monotonically through development. Thus, this version of the model does not predict that proportional size increases necessarily remain constant, which is the pattern described by Dyar's Rule. A literature survey shows that in nature size increases tend to decline and instar durations to increase, but exceptions to monotonicity occur frequently: we consider how relaxing certain assumptions of the model could explain this. Having specified various functions relating fitness to adult size and time of emergence, we calculate (using dynamic programming) the effect of manipulating food availability, time of hatching and size of the initial (or some intermediate) instar. The associated norms of reaction depend on the fitness function and differ from those when growth follows Dyar's Rule or is continuous. We go on to consider optimization of the number of instars. The Investment Principle then predicts upper and lower limits to observed size increases and explains why increases usually change little or decline through development. This is thus a new adaptive explanation for Dyar's Rule and for the most common deviation from the Rule.

  12. The activity of nodules of the supernodulating mutant Mtsunn is not limited by photosynthesis under optimal growth conditions.

    PubMed

    Cabeza, Ricardo A; Lingner, Annika; Liese, Rebecca; Sulieman, Saad; Senbayram, Mehmet; Tränkner, Merle; Dittert, Klaus; Schulze, Joachim

    2014-01-01

    Legumes match the nodule number to the N demand of the plant. When a mutation in the regulatory mechanism deprives the plant of that ability, an excessive number of nodules are formed. These mutants show low productivity in the fields, mainly due to the high carbon burden caused through the necessity to supply numerous nodules. The objective of this study was to clarify whether through optimal conditions for growth and CO2 assimilation a higher nodule activity of a supernodulating mutant of Medicago truncatula (M. truncatula) can be induced. Several experimental approaches reveal that under the conditions of our experiments, the nitrogen fixation of the supernodulating mutant, designated as sunn (super numeric nodules), was not limited by photosynthesis. Higher specific nitrogen fixation activity could not be induced through short- or long-term increases in CO2 assimilation around shoots. Furthermore, a whole plant P depletion induced a decline in nitrogen fixation, however this decline did not occur significantly earlier in sunn plants, nor was it more intense compared to the wild-type. However, a distinctly different pattern of nitrogen fixation during the day/night cycles of the experiment indicates that the control of N2 fixing activity of the large number of nodules is an additional problem for the productivity of supernodulating mutants. PMID:24727372

  13. The Activity of Nodules of the Supernodulating Mutant Mtsunn Is not Limited by Photosynthesis under Optimal Growth Conditions

    PubMed Central

    Cabeza, Ricardo A.; Lingner, Annika; Liese, Rebecca; Sulieman, Saad; Senbayram, Mehmet; Tränkner, Merle; Dittert, Klaus; Schulze, Joachim

    2014-01-01

    Legumes match the nodule number to the N demand of the plant. When a mutation in the regulatory mechanism deprives the plant of that ability, an excessive number of nodules are formed. These mutants show low productivity in the fields, mainly due to the high carbon burden caused through the necessity to supply numerous nodules. The objective of this study was to clarify whether through optimal conditions for growth and CO2 assimilation a higher nodule activity of a supernodulating mutant of Medicago truncatula (M. truncatula) can be induced. Several experimental approaches reveal that under the conditions of our experiments, the nitrogen fixation of the supernodulating mutant, designated as sunn (super numeric nodules), was not limited by photosynthesis. Higher specific nitrogen fixation activity could not be induced through short- or long-term increases in CO2 assimilation around shoots. Furthermore, a whole plant P depletion induced a decline in nitrogen fixation, however this decline did not occur significantly earlier in sunn plants, nor was it more intense compared to the wild-type. However, a distinctly different pattern of nitrogen fixation during the day/night cycles of the experiment indicates that the control of N2 fixing activity of the large number of nodules is an additional problem for the productivity of supernodulating mutants. PMID:24727372

  14. School achievement in treated PKU children.

    PubMed

    Fishler, K; Azen, C G; Friedman, E G; Koch, R

    1989-12-01

    Phenylketonuric children who were treated early and maintained a pherestricted diet through age 10 were compared with those who discontinued the diet after age 6 on a standardized test of intelligence, school achievement, language and perceptual skills. Mean IQ, reading and spelling test scores improved between ages 6 and 10 for the on-diet children in comparison to those who were off-diet. However, mean scores on arithmetic, language and perceptual skills declined at a uniform rate for both groups. Children with PKU scored significantly lower than did their non-PKU siblings on tests of visual perception and visual-motor skills. Because the school years, particularly, the early teens, pose increased stress in affected PKU individuals, it is recommended that dietary restriction at least through the high school years is prudent for their optimal physical, mental, emotional and educational growth. PMID:2614816

  15. Individualizing Growth Hormone Dosing in Children

    Microsoft Academic Search

    Kuk-Wha Lee; Pinchas Cohen

    2001-01-01

    Much has been learned over the last three decades regarding the management of growth hormone (GH) treatment in children and adolescents. Current GH therapy enables most GH-treated children to attain a final height within the normal range and close to their target height. However, an optimal outcome is not always achieved and the approach to GH dosing differs among physicians

  16. NH2-terminal cleavage of xenopus fibroblast growth factor 3 is necessary for optimal biological activity and receptor binding.

    PubMed

    Antoine, M; Daum, M; Köhl, R; Blecken, V; Close, M J; Peters, G; Kiefer, P

    2000-11-01

    Fibroblast growth factor 3 (FGF3) was originally identified as the mouse proto-oncogene Int-2, which is activated by proviral insertion in tumors induced by mouse mammary tumor virus. To facilitate the biological characterization of the ligand, we have analyzed its homologue in Xenopus laevis, XFGF3. Here we confirm that the X. laevis genome contains two distinct FGF3 alleles, neither of which is capable of encoding the NH2-terminally extended forms specified by the mouse and human FGF3 genes. Unlike the mammalian proteins, XFGF3 is efficiently secreted as a Mr 31,000 glycoprotein, gp31, which undergoes proteolytic cleavage to produce an NH2-terminally truncated product, gp27. Processing removes a segment of 18 amino acids immediately distal to the signal peptide that is not present in the mammalian homologues. By inserting an epitope-tag adjacent to the cleavage site, we show that a substantial amount of the gp27 is generated intracellularly, although processing can also occur in the extracellular matrix. Two residues are also removed from the COOH terminus. To compare the biological properties of the different forms, cDNAs were constructed that selectively give rise to the larger, gp31, or smaller, gp27, forms of XFGF3. As judged by their ability to cause morphological transformation of NIH3T3 cells, their mitogenicity on specific cell types, and their affinity for the IIIb and IIIc isoforms of Xenopus FGF receptors, gp27 has a much higher biological activity than gp31. Sequence comparison revealed an intriguing similar cleavage motif immediately downstream of the signal peptide cleavage site in the NH2-terminus of mouse and human FGF3. Analysis of secreted mutant mouse FGF3 confirmed an additional NH2-terminal processing at the corresponding sequence motif. NH2-terminal trimming of Xenopus and mammalian FGF3s may therefore be a prerequisite of optimal biological activity. PMID:11095248

  17. Self-Beliefs and Student Goal Achievement

    ERIC Educational Resources Information Center

    Wesson, Caroline J.; Derrer-Rendall, Nicola M.

    2011-01-01

    Two preliminary studies are presented investigating the self-beliefs that may affect goal achievement in a student population. In Study 1, goal achievement on an abstract task, where goals are externally set by others, is considered in relation to students' levels of optimism. In Study 2, goal achievement on academic performance, where goals are…

  18. A Nuclear Localization of the Infectious Haematopoietic Necrosis Virus NV Protein Is Necessary for Optimal Viral Growth

    Microsoft Academic Search

    Myeong Kyu Choi; Chang Hoon Moon; Myoung Seok Ko; Unn-Hwa Lee; Wha Ja Cho; Seung Ju Cha; Jeong Wan Do; Gang Joon Heo; Soo Geun Jeong; Yoo Sik Hahm; Abdallah Harmache; Michel Bremont; Gael Kurath; Jeong Woo Park

    2011-01-01

    The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection

  19. Using Attitudinal Questionnaires to Achieve Benefits Optimization

    PubMed Central

    Lundsgaarde, Henry P.; Gardner, Reed M.; Menlove, Ron L.

    1989-01-01

    The evaluation of complex hospital medical and management information systems presents many complex methodological and logistical problems. Many studies, best characterized as outcome or summative evaluations, customarily document failures and successes associated with system implementation. We approach system implementation as an indeterminable process and evaluation as a management tool that can provide essential and timely feedback to both system developers and users. This paper discusses our ongoing and formative evaluation study of the transplacement of the HELP system from the LDS hospital in Salt Lake City to the McKay-Dee Hospital in Ogden, Utah. Surveys of future system users did not show any significant differences between three major groups of respondents (physicians, nurses, and staff) in terms of preferences for user education methods. The results of our work suggest that a formative evaluation study can facilitate system adoption and utilization without compromising concurrent needs of scientific objectivity.

  20. School Size, Achievement, and Achievement Gaps

    Microsoft Academic Search

    Bradley J. McMillen

    2004-01-01

    In order to examine the relationship between school size and achievement, a study was conducted using longitudinal achievement data from North Carolina for three separate cohorts of public school students (one elementary, one middle and one high school). Results revealed several interactions between size and student characteristics, all of which indicated that the achievement gaps typically existing between certain subgroups

  1. Optimization of growth parameters for MOVPE-grown GaSb and Ga 1? x In x Sb

    Microsoft Academic Search

    S. S. Miya; V. Wagener; J. R. Botha

    The triethylgallium\\/trimethylantimony (TEGa\\/TMSb) precursor combination was used for the metal-organic vapour phase epitaxial growth of GaSb at a growth temperature of 520°C at atmospheric pressure. Trimethylindium was added in the case of Ga1?xInxSb growth. The effects of group V flux to group III flux ratio (V\\/III ratio) on the crystallinity and optical properties of GaSb layers are reported. It has

  2. Growth parameter optimization and interface treatment for enhanced electron mobility in heavily strained GaInAs/AlInAs high electron mobility transistor structures

    SciTech Connect

    Fedoryshyn, Yuriy; Ostinelli, Olivier; Alt, Andreas; Pallin, Angel; Bolognesi, Colombo R., E-mail: colombo@ieee.org [Millimeter-Wave-Electronics Group, ETH Zurich, 8092 Zurich (Switzerland)

    2014-01-28

    The optimization of heavily strained Ga{sub 0.25}In{sub 0.75}As/Al{sub 0.48}In{sub 0.52}As high electron mobility transistor structures is discussed in detail. The growth parameters and the channel layer interfaces were optimized in order to maximize the mobility of the two-dimensional electron gas. Structures composed of an 11?nm thick channel layer and a 4?nm thick spacer layer exhibited electron mobilities as high as 15?100 cm{sup 2}/Vs and 70?000 cm{sup 2}/Vs at 300 and 77?K, respectively, for channels including InAs strained layers. The sheet carrier density was kept above 2.5?×?10{sup 12}?cm{sup ?2} throughout the entire study.

  3. Acclimation dynamics and sub-optimality in carbon allocation for C3 and C4 plants subject to growth under elevated CO2

    NASA Astrophysics Data System (ADS)

    Srinivasan, V.; Kumar, P.

    2012-12-01

    Soybean-Maize agro ecosystem covers about 9% of the mainland US and its acclimation response due to climate change has the potential to significantly impact local and regional ecohydrology and climate. C3 and C4 species exhibit different acclimation strategies to elevated CO2 in terms of their carbon assimilation. While C3 species have a direct enhancement in carbon assimilation, C4 species have a mild indirect carbon assimilation enhancement effect due to decreased water stress. However, the fate of the assimilated carbon in terms of its allocation to different plant parts remains unknown to a large extent. This has the potential to alter above and below ground respiration water uptake patterns and crop productivity. In this study, we investigate the dynamics of carbon allocation, translocation and partitioning in C3 and C4 plants under ambient and elevated CO2 conditions using a multi-layer land surface model MLCan (Drewry et al. 2010) and flux and biomass data from Ameriflux and SoyFACE research facilities (Morgan et al. 2004). Furthermore, we compare the observed carbon allocation patterns with an optimal carbon allocation model that maximizes end of season seed yield. Our results show that, only C3 species exhibits acclimation response in carbon allocation under elevated CO2. While the structural, bio-chemical and eco-physiological acclimation effect of elevated CO2 in C3 plants have been documented in earlier studies (Drewry et al. 2010), our study provides a direct evidence of carbon allocation acclimation in C3 plants. Under acclimation C3 plants allocate more carbon to vegetative parts (leaf, stem and root) compared to reproductive part (seed) thus changing their allometric relationships. This explains the apparent lower than expected yields in C3 plants observed in FACE experiments (Morgan et al 2004). Comparison of our results with an optimal carbon allocation model reveals that under ambient CO2 concentrations, C3 and C4 plants allocate sub-optimally with respect to maximizing end of season seed biomass. Furthermore, when comparing observed carbon allocation patterns with the optimality results under elevated CO2 growing conditions, the extent of sub-optimality is amplified in C3 plant species. Experimental manipulations of plant carbon allocation patterns guided by model results confirm this sub-optimal effect. Our results demonstrate that allometric relationships cannot be used to model carbon allocation and growth of C3 plants under acclimation due to elevated CO2. The observed sub-optimality in ambient CO2 conditions and the increased sub-optimality under elevated CO2 conditions indicate that a teleonomic approach might be incomplete in capturing acclimation aspects of plant growth. We hypothesize that the observed sub-optimality is caused by a resilience constraint whereby plants device a carbon allocation strategy that maximizes end of season seed yield subject to variability in climate forcing. Since, the teleonomic approach provides the necessary degrees of freedom to capture changes in allometric relationships we suggest that incorporating a suitable resilience constraint within the optimality framework can explain the observed sub-optimal behavior.

  4. 64 ?W pulsed terahertz emission from growth optimized InGaAs/InAlAs heterostructures with separated photoconductive and trapping regions

    SciTech Connect

    Dietz, Roman J. B.; Globisch, Björn; Stanze, Dennis; Roehle, Helmut; Göbel, Thorsten; Schell, Martin [Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institute, Einsteinufer 37, 10587 Berlin (Germany)] [Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institute, Einsteinufer 37, 10587 Berlin (Germany); Gerhard, Marina; Velauthapillai, Ajanthkrishna; Koch, Martin [Department of Physics, Philipps-Universität Marburg, Renthof 5, 35032 Marburg (Germany)] [Department of Physics, Philipps-Universität Marburg, Renthof 5, 35032 Marburg (Germany)

    2013-08-05

    We present results on optimized growth temperatures and layer structure design of high mobility photoconductive Terahertz (THz) emitters based on molecular beam epitaxy grown In{sub 0.53}Ga{sub 0.47}As/In{sub 0.52}Al{sub 0.48}As multilayer heterostructures (MLHS). The photoconductive antennas made of these MLHS are evaluated as THz emitters in a THz time domain spectrometer and with a Golay cell. We measured a THz bandwidth in excess of 4 THz and average THz powers of up to 64 ?W corresponding to an optical power-to-THz power conversion efficiency of up to 2 × 10{sup ?3}.

  5. Culture of Primary Rat Hippocampal Neurons: Design, Analysis, and Optimization of a Microfluidic Device for Cell Seeding, Coherent Growth, and Solute Delivery

    PubMed Central

    Barbati, A. C.; Fang, C.; Banker, G. A.; Kirby, B. J.

    2013-01-01

    We present the design, analysis, construction, and culture results of a microfluidic device for the segregation and chemical stimulation of primary rat hippocampal neurons. Our device is designed to achieve spatio temporal solute delivery to discrete sections of neurons with mitigated mechanical stress. We implement a geometric guidance technique to direct axonal processes of the neurons into specific areas of the device to achieve solute segregation along routed cells. Using physicochemical modeling, we predict flows, concentration profiles, and mechanical stresses within pertiment sections of the device. We demonstrate cell viability and growth within the closed device over a period of 11 days. Additionally, our modeling methodology may be generalized and applied to other device geometries. PMID:22965807

  6. Pyridodiazepine Amines Are Selective Therapeutic Agents for Helicobacter pylori by Suppressing Growth through Inhibition of Glutamate Racemase but Are Predicted To Require Continuous Elevated Levels in Plasma To Achieve Clinical Efficacy.

    PubMed

    de Jonge, Boudewijn L M; Kutschke, Amy; Newman, Joseph V; Rooney, Michael T; Yang, Wei; Cederberg, Christer

    2015-04-01

    A pyridodiazepine amine inhibitor of Helicobacter pylori glutamate racemase (MurI) was characterized. The compound was selectively active against H. pylori, and growth suppression was shown to be mediated through the inhibition of MurI by several methods. In killing kinetics experiments, the compound showed concentration-independent activity, with about a 2-log loss of viability in 24 h. A demonstration of efficacy in a mouse infection model was attempted but not achieved, and this was attributed to the failure to attain extended exposure levels above the MIC for >95% of the time. This index and magnitude were derived from pharmacokinetic-pharmacodynamic (PK-PD) studies with amoxicillin, another inhibitor of peptidoglycan biosynthesis that showed slow killing kinetics similar to those of the pyridodiazepine amines. These studies indicate that MurI and other enzymes involved in peptidoglycan biosynthesis may be less desirable targets for monotherapy directed against H. pylori if once-a-day dosing is required. PMID:25645840

  7. Optimization of chemical bath deposited CdS thin films using nitrilotriacetic acid as a complexing agent

    Microsoft Academic Search

    Hani Khallaf; Isaiah O. Oladeji; Lee Chow

    2008-01-01

    We report a design of experiment approach for the optimization of CdS thin films grown by chemical bath deposition using nitrilotriacetic acid (NTA) as a complexing agent. With the help of this approach, we developed a set of experiments that enabled us to maximize the growth rate. In comparison with works reported earlier, a much faster growth rate is achieved.

  8. Embryonic pig liver, pancreas, and lung as a source for transplantation: Optimal organogenesis without teratoma depends on distinct time windows

    Microsoft Academic Search

    Smadar Eventov-Friedman; Helena Katchman; Elias Shezen; Anna Aronovich; Dalit Tchorsh; Benjamin Dekel; Enrique Freud; Yair Reisner

    2005-01-01

    Pig embryonic tissues represent an attractive option for organ transplantation. However, the achievement of optimal organogenesis after transplantation, namely, maximal organ growth and function without teratoma development, represents a major challenge. In this study, we determined distinct gestational time windows for the growth of pig embryonic liver, pancreas, and lung precursors. Transplantation of embryonic-tissue precursors at various gestational ages [from

  9. Make It Go Viral! Rate-optimal Control for Resource-Constrained Branching Processes

    E-print Network

    Xu, Kuang

    2012-01-01

    We propose a new class of controlled multi-type branching processes with a per-step linear resource constraint, motivated by applications in quantitative marketing, and study the associated growth-rate maximizing control strategies. We show that the optimal growth rate can be achieved by maintaining a single optimal ratio among different population types, for both deterministic and stochastic branching processes. In the special case of a two-type population and with a symmetric revenue structure, the optimal ratio is obtained in closed-form. As a proof of concept, the methodology is applied to the linkage structure of the 2004 US Presidential Election blogosphere, where the optimal growth rate achieves sizable gains over a uniform selection strategy.

  10. Technical Note: Seeding Conditions of the Halophyte Atriplex Patula for Optimal Growth on a Salt Impacted Site

    Microsoft Academic Search

    Michelle A. Young; Doug G. Rancier; Julie L. Roy; Stuart R. Lunn; Sarah A. Armstrong; John V. Headley

    2011-01-01

    Salt-impacted soils resulting from oilfield brine spills are increasingly becoming a significant problem in oil-producing areas of Canada such as Alberta and Saskatchewan.The native halophyte Atriplex patula is being considered a potential species for phytoremediation of brine-impacted sites in these hemiboreal climactic zones. The objective of this study was to investigate the optimal seeding conditions under field conditions (with no

  11. Optimizing reproductive phenology in a two-resource world: a dynamic allocation model of plant growth predicts later reproduction in phosphorus-limited plants

    PubMed Central

    Nord, Eric A.; Shea, Katriona; Lynch, Jonathan P.

    2011-01-01

    Background and Aims Timing of reproduction is a key life-history trait that is regulated by resource availability. Delayed reproduction in soils with low phosphorus availability is common among annuals, in contrast to the accelerated reproduction typical of other low-nutrient environments. It is hypothesized that this anomalous response arises from the high marginal value of additional allocation to root growth caused by the low mobility of phosphorus in soils. Methods To better understand the benefits and costs of such delayed reproduction, a two-resource dynamic allocation model of plant growth and reproduction is presented. The model incorporates growth, respiration, and carbon and phosphorus acquisition of both root and shoot tissue, and considers the reallocation of resources from senescent leaves. The model is parameterized with data from Arabidopsis and the optimal reproductive phenology is explored in a range of environments. Key Results The model predicts delayed reproduction in low-phosphorus environments. Reproductive timing in low-phosphorus environments is quite sensitive to phosphorus mobility, but is less sensitive to the temporal distribution of mortality risks. In low-phosphorus environments, the relative metabolic cost of roots was greater, and reproductive allocation reduced, compared with high-phosphorus conditions. The model suggests that delayed reproduction in response to low phosphorus availability may be reduced in plants adapted to environments where phosphorus mobility is greater. Conclusions Delayed reproduction in low-phosphorus soils can be a beneficial response allowing for increased acquisition and utilization of phosphorus. This finding has implications both for efforts to breed crops for low-phosphorus soils, and for efforts to understand how climate change may impact plant growth and productivity in low-phosphorus environments. PMID:21712299

  12. A nuclear localization of the infectious haematopoietic necrosis virus NV protein is necessary for optimal viral growth

    USGS Publications Warehouse

    Choi, M.K.; Moon, C.H.; Ko, M.S.; Lee, U.-H.; Cho, W.J.; Cha, S.J.; Do, J.W.; Heo, G.J.; Jeong, S.G.; Hahm, Y.S.; Harmache, A.; Bremont, M.; Kurath, G.; Park, J.-W.

    2011-01-01

    The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection in RTG-2 cells of NV fused to green fluorescent protein (GFP), a nuclear localization of NV was demonstrated. Deletion analyses showed that the 32EGDL35 residues were essential for nuclear localization of NV protein, and fusion of these 4 amino acids to GFP directed its transport to the nucleus. We generated a recombinant IHNV, rIHNV-NV-?EGDL in which the 32EGDL35 was deleted from the NV. rIHNVs with wild-type NV (rIHNV-NV) or with the NV gene replaced with GFP (rIHNV-?NV-GFP) were used as controls. RTG-2 cells infected with rIHNV-?NV-GFP and rIHNV-NV-?EGDL yielded 12- and 5-fold less infectious virion, respectively, than wild type rIHNV-infected cells at 48 h post-infection (p.i.). While treatment with poly I:C at 24 h p.i. did not inhibit replication of wild-type rIHNVs, replication rates of rIHNV-?NV-GFP and rIHNV-NV-?EGDL were inhibited by poly I:C. In addition, both rIHNV-?NV and rIHNV-NV-?EGDL induced higher levels of expressions of both IFN1 and Mx1 than wild-type rIHNV. These data suggest that the IHNV NV may support the growth of IHNV through inhibition of the INF system and the amino acid residues of 32EGDL35 responsible for nuclear localization are important for the inhibitory activity of NV.

  13. Optimization of the parameters affecting the shape and position of crystal–melt interface in YAG single crystal growth

    Microsoft Academic Search

    Morteza Asadian; S. H. Seyedein; M. R. Aboutalebi; A. Maroosi

    2009-01-01

    In Czochralski method, the shape of crystal–melt interface and its position play a major role on the quality of single crystals. In the Czochralski crystal growth process having a nearly flat interface, a single crystal with less structural defect, uniform physical properties and homogenous chemical composition is obtained.In the present study, firstly a 2-D fluid flow and solidification model was

  14. Mycelium growth kinetics and optimal temperature conditions for the cultivation of edible mushroom species on lignocellulosic substrates

    Microsoft Academic Search

    G. Zervakis; A. Philippoussis; S. Ioannidou; P. Diamantopoulou

    2001-01-01

    The influence of environmental parameters on mycelial linear growth ofPleurotus ostreatus, P. eryngii, P. pulmonarius, Agrocybe aegerita, Lentinula edodes, Volvariella volvacea andAuricularia auricula-judae was determined in two different nutrient media in a wide range of temperature, forming the basis for the assessment of their\\u000a temperature optimaV. volvacea grew faster at 35°C,P. eryngii at 25°C,P. ostreatus andP. pulmonarius at 30°C,A. aegerita

  15. Chlamydia pneumoniae harness host NLRP3 inflammasome-mediated caspase-1 activation for optimal intracellular growth in murine macrophages.

    PubMed

    Itoh, Ryota; Murakami, Issaku; Chou, Bin; Ishii, Kazunari; Soejima, Toshinori; Suzuki, Toshihiko; Hiromatsu, Kenji

    2014-09-26

    Chlamydia pneumoniae is an obligate intracellular pathogen that replicates within a vacuole and acquires host cell nutrients. We show that C. pneumoniae utilizes host innate immune signaling NLRP3/ASC/caspase-1 inflammasome for intracellular growth. Bone marrow-derived macrophages (BMMs) secreted mature interleukin-1? upon infection with C. pneumoniae depending on the NLRP3 inflammasome activation. Intracellular growth of C. pneumoniae was severely impaired in BMMs from Nlrp3(-/-), Asc(-/-), and Casp1(-/-) mice but not wild type or Nlrc4(-/-) mice. Furthermore defective NLRP3 inflammasome components led to accumulation of lipid droplets inside the infected BMMs, suggesting that uptake and/or utilization of lipids is disturbed in the absence of NLRP3 inflammasome activation. These results suggest C. pneumoniae has evolved to harness both host innate immune response and NLRP3 inflammasome activation, for the acquisition of essential nutrients necessary for intracellular growth. This unique property of C. pneumoniae may shed a new light on how C. pneumoniae increase the risk of atherosclerosis and metabolic syndrome. PMID:25193701

  16. Optimization of electrospun TSF nanofiber alignment and diameter to promote growth and migration of mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Qu, Jing; Zhou, Dandan; Xu, Xiaojing; Zhang, Feng; He, Lihong; Ye, Rong; Zhu, Ziyu; Zuo, Baoqi; Zhang, Huanxiang

    2012-11-01

    Silk fibroin scaffolds are a naturally derived biocompatible matrix with the potential for reconstructive surgical applications. In this study, tussah silk fibroin (TSF) nanofiber with different diameters (400 nm, 800 nm and 1200 nm) and alignment (random and aligned) were prepared by electrospinning, then the growth and migration of mesenchymal stem cells (MSCs) on these materials were further evaluated. CD90 immunofluorescence staining showed that fiber alignment exhibited a strong influence on the morphology of MSCs, indicating that the alignment of the scaffolds could determine the distribution of cells. Moreover, smaller diameter and aligned TSF scaffolds are more favorable to the growth of MSCs as compared with 800 nm and 1200 nm random TSF scaffolds. In addition, the increased migration speed and efficiency of MSCs induced by three-D TSF were verified, highlighting the guiding roles of TSF to the migrated MSCs. More importantly, 400 nm aligned TSF scaffolds dramatically improved cell migratory speed and further induced the most efficient migration of MSCs as compared with larger diameter TSF scaffolds. In conclusion, the data demonstrate that smaller diameter and aligned electrospun TSF represent valuable scaffolds for supporting and promoting MSCs growth and migration, thus raising the possibility of manipulating TSF scaffolds to enhance homing and therapeutic potential of MSCs in cellular therapy.

  17. Thermal properties and optimization of process parameters for the growth of silver thiogallate crystal by differential scanning calorimetry

    NASA Astrophysics Data System (ADS)

    He, Zhiyu; Zhao, Beijun; Zhu, Shifu; Chen, Baojun; Huang, Wei

    2014-09-01

    In present work, thermal properties of silver thiogallate (AgGaS2) crystal were investigated by means of differential scanning calorimetry (DSC) measurements performed at different heating and cooling rates. The DSC results confirmed that the melting point was 1249 K with a slight change around 5 K and that the nucleation temperature varied from 1183 K to 1218 K. The supercooling temperature was evaluated in the range 37.69 K to 62.46 K which was considered to be harmful for the single nucleus formation at the beginning of crystal growth. The activation energy E and the pre-exponential factor A were also calculated using different isoconversional methods, namely Kissinger-Akahira-Sunose (KAS) method and Flynn-Wall-Ozawa (FWO) method, and the results showed good agreement with each other. According to the results of DSC, a larger temperature gradient up to 30 K/cm was utilized to suppress the formation and growth of multi nuclei and a rapid cooling rate 25 K/min was applied to minimize the second-phase precipitates during the process of crystal growth. Finally, an integral and transparent AgGaS2 single crystal with diameter of 22 mm and the length of 55 mm was obtained.

  18. Mycelium growth kinetics and optimal temperature conditions for the cultivation of edible mushroom species on lignocellulosic substrates.

    PubMed

    Zervakis, G; Philippoussis, A; Ioannidou, S; Diamantopoulou, P

    2001-01-01

    The influence of environmental parameters on mycelial linear growth of Pleurotus ostreatus, P. eryngii, P. pulmonarius, Agrocybe aegerita, Lentinula edodes, Volvariella volvacea and Auricularia auricula-judae was determined in two different nutrient media in a wide range of temperature, forming the basis for the assessment of their temperature optima. V. volvacea grew faster at 35 degrees C, P. eryngii at 25 degrees C, P. ostreatus and P. pulmonarius at 30 degrees C, A. aegerita at 25 or 30 degrees C and A. auricula-judae at 20 or 25 degrees C depending on the nutrient medium used and L. edodes at 20 or 30 degrees C depending on the strain examined. The mycelium extension rates were evaluated on seven mushroom cultivation substrates: wheat straw, cotton gin-trash, peanut shells, poplar sawdust, oak sawdust, corn cobs and olive press-cake. The mycelium extension rates (linear growth and colonization rates) were determined by the 'race-tube' technique, and were found to be the highest on cotton gin-trash, peanut shells and poplar sawdust for Pleurotus spp. and A. aegerita. Wheat straw, peanut shells and particularly cotton gin-trash supported fast growth of V. volvacea, whereas wheat straw was the most suitable substrate for L. edodes and A. auricula-judae. Supplemented oak sawdust and olive press-cake were poor substrates for most species examined, while almost all strains performed adequately on corn cobs. PMID:11702409

  19. Which Achievement Gap?

    ERIC Educational Resources Information Center

    Anderson, Sharon; Medrich, Elliott; Fowler, Donna

    2007-01-01

    From the halls of Congress to the local elementary school, conversations on education reform have tossed around the term "achievement gap" as though people all know precisely what that means. As it's commonly used, "achievement gap" refers to the differences in scores on state or national achievement tests between various student demographic…

  20. Mobility and Reading Achievement.

    ERIC Educational Resources Information Center

    Waters, Theresa Z.

    A study examined the effect of geographic mobility on elementary school students' achievement. Although such mobility, which requires students to make multiple moves among schools, can have a negative impact on academic achievement, the hypothesis for the study was that it was not a determining factor in reading achievement test scores. Subjects…

  1. Realization of InGaN laser diodes above 500 nm by growth optimization of the InGaN/GaN active region

    NASA Astrophysics Data System (ADS)

    Liu, Jianping; Li, Zengcheng; Zhang, Liqun; Zhang, Feng; Tian, Aiqing; Zhou, Kun; Li, Deyao; Zhang, Shuming; Yang, Hui

    2014-11-01

    Two-step growth was employed to grow GaN quantum barriers (QBs) in InGaN green LD structures. A cap layer was grown at the same temperature as an InGaN quantum well (QW), and the temperature was then raised by around 130 °C to grow GaN QBs. The effects of low-temperature-grown cap (LT-cap) layers on the optical properties and microstructures of green LD structures were investigated. It was found that the LT-cap layer with an optimal thickness can improve the luminescence homogeneity and suppress the thermal decomposition of InGaN QWs. C-plane ridge waveguide laser diodes lasing above 500 nm were realized.

  2. AMT1;1 transgenic rice plants with enhanced NH4 + permeability show superior growth and higher yield under optimal and suboptimal NH4 + conditions

    PubMed Central

    Rothstein, Steven J.

    2014-01-01

    The major source of nitrogen for rice (Oryza sativa L.) is ammonium (NH4 +). The NH4 + uptake of roots is mainly governed by membrane transporters, with OsAMT1;1 being a prominent member of the OsAMT1 gene family that is known to be involved in NH4 + transport in rice plants. However, little is known about its involvement in NH4 + uptake in rice roots and subsequent effects on NH4 + assimilation. This study shows that OsAMT1;1 is a constitutively expressed, nitrogen-responsive gene, and its protein product is localized in the plasma membrane. Its expression level is under the control of circadian rhythm. Transgenic rice lines (L-2 and L-3) overexpressing the OsAMT1;1 gene had the same root structure as the wild type (WT). However, they had 2-fold greater NH4 + permeability than the WT, whereas OsAMT1;1 gene expression was 20-fold higher than in the WT. Analogous to the expression, transgenic lines had a higher NH4 + content in the shoots and roots than the WT. Direct NH4 + fluxes in the xylem showed that the transgenic lines had significantly greater uptake rates than the WT. Higher NH4 + contents also promoted higher expression levels of genes in the nitrogen assimilation pathway, resulting in greater nitrogen assimilates, chlorophyll, starch, sugars, and grain yield in transgenic lines than in the WT under suboptimal and optimal nitrogen conditions. OsAMT1;1 also enhanced overall plant growth, especially under suboptimal NH4 + levels. These results suggest that OsAMT1;1 has the potential for improving nitrogen use efficiency, plant growth, and grain yield under both suboptimal and optimal nitrogen fertilizer conditions. PMID:24420570

  3. Quantitative Genetics and Functional–Structural Plant Growth Models: Simulation of Quantitative Trait Loci Detection for Model Parameters and Application to Potential Yield Optimization

    PubMed Central

    Letort, Véronique; Mahe, Paul; Cournède, Paul-Henry; de Reffye, Philippe; Courtois, Brigitte

    2008-01-01

    Background and Aims Prediction of phenotypic traits from new genotypes under untested environmental conditions is crucial to build simulations of breeding strategies to improve target traits. Although the plant response to environmental stresses is characterized by both architectural and functional plasticity, recent attempts to integrate biological knowledge into genetics models have mainly concerned specific physiological processes or crop models without architecture, and thus may prove limited when studying genotype × environment interactions. Consequently, this paper presents a simulation study introducing genetics into a functional–structural growth model, which gives access to more fundamental traits for quantitative trait loci (QTL) detection and thus to promising tools for yield optimization. Methods The GREENLAB model was selected as a reasonable choice to link growth model parameters to QTL. Virtual genes and virtual chromosomes were defined to build a simple genetic model that drove the settings of the species-specific parameters of the model. The QTL Cartographer software was used to study QTL detection of simulated plant traits. A genetic algorithm was implemented to define the ideotype for yield maximization based on the model parameters and the associated allelic combination. Key Results and Conclusions By keeping the environmental factors constant and using a virtual population with a large number of individuals generated by a Mendelian genetic model, results for an ideal case could be simulated. Virtual QTL detection was compared in the case of phenotypic traits – such as cob weight – and when traits were model parameters, and was found to be more accurate in the latter case. The practical interest of this approach is illustrated by calculating the parameters (and the corresponding genotype) associated with yield optimization of a GREENLAB maize model. The paper discusses the potentials of GREENLAB to represent environment × genotype interactions, in particular through its main state variable, the ratio of biomass supply over demand. PMID:17766844

  4. Culture-Independent Estimation of Optimal and Maximum Growth Temperatures of Archaea in Subsurface Habitats Based on the G+C Content in 16S rRNA Gene Sequences

    Microsoft Academic Search

    Hiroyuki Kimura; Kousuke Mori; Tomokazu Tashiro; Kenji Kato; Toshiro Yamanaka; Jun-Ichiro Ishibashi; Satoshi Hanada

    2010-01-01

    The temperature ranges of growth of archaea are strongly correlated with the guanine-plus-cytosine (G+C) contents of their 16S rRNA sequences (PGC). In order to estimate minimum (Tmin), optimal (Topt), and maximum (Tmax) growth temperatures of uncultured archaea based on PGC, the 16S rRNA gene sequences of 207 archaeal species were collected from public databases, and their Tmin, Topt and Tmax

  5. Manipulating Crystallographic Texture of Sn Coatings by Optimization of Electrodeposition Process Conditions to Suppress Growth of Whiskers

    NASA Astrophysics Data System (ADS)

    Jagtap, Piyush; Kumar, Praveen

    2015-01-01

    The effects of two major electrodeposition process conditions, electrolyte bath temperature and current density, on the microstructure and crystallographic texture of pure tin coatings on brass and, ultimately, on the extent of whisker formation have been examined. The grain size of the deposited coatings increased with increasing electrolyte bath temperature and current density, which significantly affected the dominant texture: (211) or (420) was the dominant texture at low current densities whereas, depending on deposition temperature, (200) or (220) became the dominant texture at high current densities. After deposition, coatings were subjected to different environmental conditions, for example isothermal aging (room temperature, 50°C, or 150°C) for up to 90 days and thermal cycling between -25°C and 85°C for 100 cycles, and whisker growth was studied. The Sn coatings with low Miller index planes, for example (200) and (220), and with moderate aging temperature were more prone to whiskering than coating with high Miller index planes, for example (420), and high aging temperature. A processing route involving the optimum combination of current density and deposition temperature is proposed for suppressing whisker growth.

  6. Manipulating Crystallographic Texture of Sn Coatings by Optimization of Electrodeposition Process Conditions to Suppress Growth of Whiskers

    NASA Astrophysics Data System (ADS)

    Jagtap, Piyush; Kumar, Praveen

    2015-04-01

    The effects of two major electrodeposition process conditions, electrolyte bath temperature and current density, on the microstructure and crystallographic texture of pure tin coatings on brass and, ultimately, on the extent of whisker formation have been examined. The grain size of the deposited coatings increased with increasing electrolyte bath temperature and current density, which significantly affected the dominant texture: (211) or (420) was the dominant texture at low current densities whereas, depending on deposition temperature, (200) or (220) became the dominant texture at high current densities. After deposition, coatings were subjected to different environmental conditions, for example isothermal aging (room temperature, 50°C, or 150°C) for up to 90 days and thermal cycling between -25°C and 85°C for 100 cycles, and whisker growth was studied. The Sn coatings with low Miller index planes, for example (200) and (220), and with moderate aging temperature were more prone to whiskering than coating with high Miller index planes, for example (420), and high aging temperature. A processing route involving the optimum combination of current density and deposition temperature is proposed for suppressing whisker growth.

  7. Optimization of processing parameters on the controlled growth of ZnO nanorod arrays for the performance improvement of solid-state dye-sensitized solar cells

    SciTech Connect

    Lee, Yi-Mu, E-mail: ymlee@nuu.edu.t [Department of Electronic Engineering, National United University, MiaoLi 36003, Taiwan (China); Yang, Hsi-Wen [Department of Materials Science and Engineering, National United University, MiaoLi 36003, Taiwan (China)

    2011-03-15

    High-transparency and high quality ZnO nanorod arrays were grown on the ITO substrates by a two-step chemical bath deposition (CBD) method. The effects of processing parameters including reaction temperature (25-95 {sup o}C) and solution concentration (0.01-0.1 M) on the crystal growth, alignment, optical and electrical properties were systematically investigated. It has been found that these process parameters are critical for the growth, orientation and aspect ratio of the nanorod arrays, showing different structural and optical properties. Experimental results reveal that the hexagonal ZnO nanorod arrays prepared under reaction temperature of 95 {sup o}C and solution concentration of 0.03 M possess highest aspect ratio of {approx}21, and show the well-aligned orientation and optimum optical properties. Moreover the ZnO nanorod arrays based heterojunction electrodes and the solid-state dye-sensitized solar cells (SS-DSSCs) were fabricated with an improved optoelectrical performance. -- Graphical abstract: The ZnO nanorod arrays demonstrate well-alignment, high aspect ratio (L/D{approx}21) and excellent optical transmittance by low-temperature chemical bath deposition (CBD). Display Omitted Research highlights: > Investigate the processing parameters of CBD on the growth of ZnO nanorod arrays. > Optimization of CBD process parameters: 0.03 M solution concentration and reaction temperature of 95 {sup o}C. > The prepared ZnO samples possess well-alignment and high aspect ratio (L/D{approx}21). > An n-ZnO/p-NiO heterojunction: great rectifying behavior and low leakage current. > SS-DSSC has J{sub SC} of 0.31 mA/cm{sup 2} and V{sub OC} of 590 mV, and an improved {eta} of 0.059%.

  8. Genome-Wide Mutant Fitness Profiling Identifies Nutritional Requirements for Optimal Growth of Yersinia pestis in Deep Tissue

    PubMed Central

    Palace, Samantha G.; Proulx, Megan K.; Lu, Shan; Baker, Richard E.

    2014-01-01

    ABSTRACT Rapid growth in deep tissue is essential to the high virulence of Yersinia pestis, causative agent of plague. To better understand the mechanisms underlying this unusual ability, we used transposon mutagenesis and high-throughput sequencing (Tn-seq) to systematically probe the Y. pestis genome for elements contributing to fitness during infection. More than a million independent insertion mutants representing nearly 200,000 unique genotypes were generated in fully virulent Y. pestis. Each mutant in the library was assayed for its ability to proliferate in vitro on rich medium and in mice following intravenous injection. Virtually all genes previously established to contribute to virulence following intravenous infection showed significant fitness defects, with the exception of genes for yersiniabactin biosynthesis, which were masked by strong intercellular complementation effects. We also identified more than 30 genes with roles in nutrient acquisition and metabolism as experiencing strong selection during infection. Many of these genes had not previously been implicated in Y. pestis virulence. We further examined the fitness defects of strains carrying mutations in two such genes—encoding a branched-chain amino acid importer (brnQ) and a glucose importer (ptsG)—both in vivo and in a novel defined synthetic growth medium with nutrient concentrations matching those in serum. Our findings suggest that diverse nutrient limitations in deep tissue play a more important role in controlling bacterial infection than has heretofore been appreciated. Because much is known about Y. pestis pathogenesis, this study also serves as a test case that assesses the ability of Tn-seq to detect virulence genes. PMID:25139902

  9. Using School-Level Student Achievement to Engage in Formative Evaluation: Comparative School-Level Rates of Oral Reading Fluency Growth Conditioned by Initial Skill for Second Grade Students

    ERIC Educational Resources Information Center

    Cummings, Kelli D.; Stoolmiller, Michael L.; Baker, Scott K.; Fien, Hank; Kame'enui, Edward J.

    2015-01-01

    We present a method for data-based decision making at the school level using student achievement data. We demonstrate the potential of a national assessment database [i.e., the University of Oregon DIBELS Data System (DDS)] to provide comparative levels of school-level data on average student achievement gains. Through the DDS as a data source,…

  10. The importance of optimal nutrition How an unhealthy and unbalanced diet in the first years of life can have profound effects on growth and development of body and mind - and how to avoid them

    Microsoft Academic Search

    S. Karger AG; Manuela Obrist

    2008-01-01

    9.6 million children die every year from hunger and malnutrition. Malnutrition hinders fetal development, weakens the immune system, impairs physical and mental health, slows thinking, saps energy, stunts growth and leads to infectious disease: optimal nutrition - especially in the early years of life - is of literally vital importance. This book provides concise information to doctors seeking quick guidance

  11. Achieving Public Schools

    ERIC Educational Resources Information Center

    Abowitz, Kathleen Knight

    2011-01-01

    Public schools are functionally provided through structural arrangements such as government funding, but public schools are achieved in substance, in part, through local governance. In this essay, Kathleen Knight Abowitz explains the bifocal nature of achieving public schools; that is, that schools are both subject to the unitary Public compact of…

  12. Assessing Handwriting Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    2002-01-01

    Notes that handwriting achievement can be assessed in degrees from being legible to being illegible. Suggests that a rubric, carefully developed and designed, may well be used to ascertain the quality of handwriting achievement. Gives a brief history of handwriting instruction. Presents 10 points for teachers to follow when teaching handwriting.…

  13. Inverting the Achievement Pyramid

    ERIC Educational Resources Information Center

    White-Hood, Marian; Shindel, Melissa

    2006-01-01

    Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

  14. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  15. Supply-Side Analysis of Growth of Bacillus subtilis on Glucose-Citrate Medium: Feasible Network Alternatives and Yield Optimality

    PubMed Central

    Lee, J.; Goel, A.; Ataai, M. M.; Domach, M. M.

    1997-01-01

    Our prior work revealed that compared to the case for glucose metabolism, increased carbon yield and nil acid formation result when Bacillus subtilis grows on glucose medium containing citrate. To scrutinize further how citrate addition may alter metabolic flux regulation and the degree that the observed carbon yield corresponds to the maximal value, experimental (by least-squares analysis) and optimal (by linear programming) fluxes and yields were contrasted. Networks with differing reaction routes, directionality constraints, and transhydrogenase activities were examined. To attain an elevated carbon yield, citrate-glucose utilization need not alleviate any stoichiometric constraints that can sometimes interfere with the attainment of network objectives. Rather, the high carbon yield and nil acid formation attained may be linked to restriction of glycolytic capacity, particularly at the level of pyruvate kinase, which is consistent with a hypothesized effect of coupled metal-citrate uptake. Allowing for malic enzyme activity, hexose monophosphate pathway cycling, and transhydrogenase activity may also lead to the flux distributions underlying the high carbon yield observed. Finally, the observed carbon yield corresponded well to the maximum yield provided by all the network alternatives examined. Collectively, these results suggest that (i) the observed carbon yield is essentially equal to the maximal values associated with plausible networks and (ii), as suggested by others, nonoptimal flux regulation may contribute significantly to apparent cellular maintenance requirements. PMID:16535522

  16. Entropy production of a steady-growth cell with catalytic reactions

    NASA Astrophysics Data System (ADS)

    Himeoka, Yusuke; Kaneko, Kunihiko

    2014-10-01

    Cells generally convert external nutrient resources to support metabolism and growth. Understanding the thermodynamic efficiency of this conversion is essential to determine the general characteristics of cellular growth. Using a simple protocell model with catalytic reaction dynamics to synthesize the necessary enzyme and membrane components from nutrients, the entropy production per unit-cell-volume growth is calculated analytically and numerically based on the rate equation for chemical kinetics and linear nonequilibrium thermodynamics. The minimal entropy production per unit-cell growth is found to be achieved at a nonzero nutrient uptake rate rather than at a quasistatic limit as in the standard Carnot engine. This difference appears because the equilibration mediated by the enzyme exists only within cells that grow through enzyme and membrane synthesis. Optimal nutrient uptake is also confirmed by protocell models with many chemical components synthesized through a catalytic reaction network. The possible relevance of the identified optimal uptake to optimal yield for cellular growth is also discussed.

  17. A longitudinal study of math achievement gains for initially low achieving students

    Microsoft Academic Search

    Cody S. Ding; Mark L. Davison

    2005-01-01

    Standardized testing has been implemented in most school districts as part of an effort to improve student achievement in mathematics, reading, science, and English. There have been heated debates as to the effects of these improvement efforts on student achievement. In studying these issues, it is important to examine longitudinal growth patterns for individuals. In most of the studies, however,

  18. Back to the Basics: In Defense of Achievement (and Achievement Tests) in College Admissions

    ERIC Educational Resources Information Center

    Geiser, Saul

    2009-01-01

    In this article, the author describes the growth and acceptance of achievement tests, such as the Scholastic Aptitude Test (SAT), over the past century, advocating that many SAT claims of equity, uniformity, technical reliability, and prediction, over traditional measures of academic achievement have been found to be illusory. Summarizing a series…

  19. Carbon nanofiber growth optimization for their use as electrocatalyst support in proton exchange membrane (PEM) fuel cells.

    PubMed

    Lázaro, M J; Sebastián, D; Suelves, I; Moliner, R

    2009-07-01

    Carbon nanofiber (CNF) growth by catalytic decomposition of methane in a fixed-bed reactor was studied out to elucidate the influence of some important reaction conditions: temperature, space velocity and reactant partial pressure, in the morphological properties of the carbonaceous material obtained. The main objective is to synthesize a suitable carbonaceous nanomaterial to be used as support in platinum based electrocatalysts for Proton Exchange Membrane Fuel Cells (PEMFC) which improves current carbon blacks. High specific surface area is required in an electrocatalyst support since platinum dispersion is enhanced and so a cost-effective usage and high catalytic activity. Good electrical conductivity of carbon support is also required since the fuel cell power density is improved. With this proposal, characterization was carried out by nitrogen physisorption, XRD, SEM and TPO. The results were analysed by a factorial design and analysis of variance (ANOVA) in order to find an empirical correlation between operating conditions and CNF characteristics. It was found that the highest specific surface area and pore volume were found at 823 K and at a space velocity of 10 L gcat(-1) h(-1). The graphitic character of CNF, which is known to influence the electrical conductivity, presented a maximum value at temperatures between 923 K and 973 K. SEM images showed a narrow size distribution of CNF diameter between 40 and 90 nm and homogeneous appearance. PMID:19916456

  20. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Meyyappan, M.

    2004-01-01

    The multitude of considerations facing nanostructure growth and integration lends itself to combinatorial optimization approaches. Rapid optimization becomes even more important with wafer-scale growth and integration processes. Here we discuss methodology for developing plasma enhanced CVD growth techniques for achieving individual, vertically aligned carbon nanostructures that show excellent properties as ultrasensitive electrodes for nucleic acid detection. We utilize high throughput strategies for optimizing the upstream and downstream processing and integration of carbon nanotube electrodes as functional elements in various device types. An overview of ultrasensitive carbon nanotube based sensor arrays for electrochemical bio-sensing applications and the high throughput methodology utilized to combine novel electrode technology with conventional MEMS processing will be presented.

  1. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Li, J.; Ye, Q.; Koehne, J.; Chen, H.; Meyyappan, M.

    2004-01-01

    The multitude of considerations facing nanostructure growth and integration lends itself to combinatorial optimization approaches. Rapid optimization becomes even more important with wafer-scale growth and integration processes. Here we discuss methodology for developing plasma enhanced CVD growth techniques for achieving individual, vertically aligned carbon nanostructures that show excellent properties as ultrasensitive electrodes for nucleic acid detection. We utilize high throughput strategies for optimizing the upstream and downstream processing and integration of carbon nanotube electrodes as functional elements in various device types. An overview of ultrasensitive carbon nanotube based sensor arrays for electrochemical biosensing applications and the high throughput methodology utilized to combine novel electrode technology with conventional MEMS processing will be presented.

  2. Optimization of struvite fertilizer formation from baker's yeast wastewater: growth and nutrition of maize and tomato plants.

    PubMed

    Uysal, Ayla; Demir, Sinan; Sayilgan, Emine; Eraslan, Figen; Kucukyumuk, Zeliha

    2014-03-01

    Struvite precipitate obtained from yeast industry anaerobic effluent with high ammonium nitrogen (NH4-N) was investigated for fertilizer effect on plant growth and nutrition according to applications of N, nitrogen/phosphorus/potassium (NPK), and control. Optimum struvite formation conditions were determined via Box-Behnken design. Optimum condition was obtained at pH 9.0 and Mg/N/P molar ratio of 1.5:1:1. Under these conditions, heavy metal concentrations in the obtained struvite precipitate (except Cu) were below the detection limits. In addition to high N, P, and Mg content, energy-dispersive X-ray (EDX) analysis showed that the struvite also included the nutritional elements Ca, K, Na, and Fe. X-ray diffraction (XRD) analysis revealed the complex structures of NaAl(SO4)2(H2O)12, NaMn(2+)Fe2(PO4)3, and (Na2,Ca)O2(Fe,Mn)O.P2O5 in the precipitate. High Na(+) and Ca(2+) concentrations in the anaerobic effluent reacted with phosphate during struvite precipitation. Different applications and struvite dosages significantly affected fresh and dry weights and nutrient element uptakes by plants (P?

  3. The Reduced Genome of the Francisella tularensis Live Vaccine Strain (LVS) Encodes Two Iron Acquisition Systems Essential for Optimal Growth and Virulence

    PubMed Central

    Pérez, Natalie Marie; Ramakrishnan, Girija

    2014-01-01

    Bacterial pathogens require multiple iron-specific acquisition systems for survival within the iron-limiting environment of the host. Francisella tularensis is a virulent intracellular pathogen that can replicate in multiple cell-types. To study the interrelationship of iron acquisition capability and virulence potential of this organism, we generated single and double deletion mutants within the ferrous iron (feo) and ferric-siderophore (fsl) uptake systems of the live vaccine strain (LVS). The Feo system was disrupted by a partial deletion of the feoB gene (?feoB?), which led to a growth defect on iron-limited modified Muller Hinton agar plates. 55Fe uptake assays verified that the ?feoB? mutant had lost the capacity for ferrous iron uptake but was still competent for 55Fe-siderophore-mediated ferric iron acquisition. Neither the ?feoB? nor the siderophore-deficient ?fslA mutant was defective for replication within J774A.1 murine macrophage-like cells, thus demonstrating the ability of LVS to survive using either ferrous or ferric sources of intracellular iron. A LVS ?fslA ?feoB? mutant defective for both ferrous iron uptake and siderophore production was isolated in the presence of exogenous F. tularensis siderophore. In contrast to the single deletion mutants, the ?fslA ?feoB? mutant was unable to replicate within J774A.1 cells and was attenuated in virulence following intraperitoneal infection of C57BL/6 mice. These studies demonstrate that the siderophore and feoB-mediated ferrous uptake systems are the only significant iron acquisition systems in LVS and that they operate independently. While one system can compensate for loss of the other, both are required for optimal growth and virulence. PMID:24695402

  4. 2013 update Achieving Excellence

    E-print Network

    Martin, Stephen John

    of the Games, using irrigation and pruning to control flowering times. Professor Dunnett said, "We wanted to the approaches to urban planting developed at Sheffield. Olympic fields of dreams Achieving Excellence Excellence

  5. ACHIEVEMENTS 7 EDUCATION 11

    E-print Network

    Acton, Scott

    ; ACHIEVEMENTS 7 EDUCATION 11 UVA~GUATEMALA 15 EMERGENCY MEDICINE RESEARCH OFFICE, and educational offerings. Please join me in congratulating physicians, nursing, residents Meeting, at a trauma meeting in Chile, and some of the national emergency

  6. Student Achievement and Motivation

    ERIC Educational Resources Information Center

    Flammer, Gordon H.; Mecham, Robert C.

    1974-01-01

    Compares the lecture and self-paced methods of instruction on the basis of student motivation and achieveme nt, comparing motivating and demotivating factors in each, and their potential for motivation and achievement. (Authors/JR)

  7. Optimization of the Production of Total Carotenoids by Sporidiobolus salmonicolor (CBS 2636) Using Response Surface Technique

    Microsoft Academic Search

    Eunice Valduga; Alexsandra Valério; Helen Treichel; Agenor Furigo Júnior; Marco Di Luccio

    2009-01-01

    This work aimed at evaluating the conditions of growth and the recovery of total carotenoids produced by Sporidiobolus salmonicolor (CBS 2636). Optimization of carotenoid production was achieved by experimental design technique. A Plackett–Burman design\\u000a was used, followed by a complete second-order design, to optimize the concentration of total carotenoids in a conventional\\u000a medium. Maximum concentration of 1,019 ?g l?1 of total

  8. Optimization of Fed-Batch Saccharomyces cereWisiae Fermentation Using Dynamic Flux Balance Models

    E-print Network

    Mountziaris, T. J.

    is that nutrient levels can be varied to achieve favorable growth conditions. Fed-batch yeast fermentation-batch yeast fermenters have been extensively investigated (10-15). These studies were based on simpleARTICLES Optimization of Fed-Batch Saccharomyces cereWisiae Fermentation Using Dynamic Flux Balance

  9. Optimization of a MRC5 Cell Culture Process for the Production of a Smallpox Vaccine

    Microsoft Academic Search

    Florence Wu; Kesav Reddy; Isabelle Nadeau; John Gilly; Sara Terpening; David J. Clanton

    2005-01-01

    A cell culture process adaptable to produce smallpox vaccine at large scale has been developed. To achieve this, Design of\\u000a Experiments (DOE) was applied to identify and optimize critical cell culture process parameters for MRC-5 cell growth and\\u000a recovery during cell expansion. For cell growth, a 25?1 partial factorial (two level, five factor, 16 conditions) study was designed to evaluate

  10. Sustaining School Achievement in California's Elementary Schools after State Monitoring

    ERIC Educational Resources Information Center

    McCabe, Molly

    2010-01-01

    This study examined the Academic Performance Index (API) and Adequate Yearly Progress (AYP) achievement trends between 2004 and 2006 of 58 California public elementary schools after exiting state monitoring and investigated practices for sustaining consistent achievement growth. Statistical methods were used to analyze statewide achievement trends…

  11. Achieving Zero Net Migration.

    ERIC Educational Resources Information Center

    Mann, Donald

    1984-01-01

    Unemployment in the United States can only be made worse by continued high levels of legal immigration. Especially serious is the threat from Latin America. We must help developing countries halt their population growth and impose a ceiling of 100,000 a year for total immigration to the United States. (RM)

  12. Assessing Handwriting Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    Teachers in the school setting need to emphasize quality handwriting across the curriculum. Quality handwriting means that the written content is easy to read in either manuscript or cursive form. Handwriting achievement can be assessed, but not compared to the precision of assessing basic addition, subtraction, multiplication, and division facts.…

  13. Intelligence and Educational Achievement

    ERIC Educational Resources Information Center

    Deary, Ian J.; Strand, Steve; Smith, Pauline; Fernandes, Cres

    2007-01-01

    This 5-year prospective longitudinal study of 70,000+ English children examined the association between psychometric intelligence at age 11 years and educational achievement in national examinations in 25 academic subjects at age 16. The correlation between a latent intelligence trait (Spearman's "g"from CAT2E) and a latent trait of educational…

  14. School Students' Science Achievement

    ERIC Educational Resources Information Center

    Shymansky, James; Wang, Tzu-Ling; Annetta, Leonard; Everett, Susan; Yore, Larry D.

    2013-01-01

    This paper is a report of the impact of an externally funded, multiyear systemic reform project on students' science achievement on a modified version of the Third International Mathematics and Science Study (TIMSS) test in 33 small, rural school districts in two Midwest states. The systemic reform effort utilized a cascading leadership strategy…

  15. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

    National learning and skills policy aims both to build economic prosperity and to achieve social justice. Participation in higher education (HE) has the potential to contribute substantially to both aims. That is why the Campaign for Learning has supported the ambition to increase the proportion of the working-age population with a Level 4…

  16. Explorations in achievement motivation

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.

    1982-01-01

    Recent research on the nature of achievement motivation is reviewed. A three-factor model of intrinsic motives is presented and related to various criteria of performance, job satisfaction and leisure activities. The relationships between intrinsic and extrinsic motives are discussed. Needed areas for future research are described.

  17. Technology and Student Achievement

    ERIC Educational Resources Information Center

    Protheroe, Nancy

    2005-01-01

    In seeking to answer the question, "Is there evidence that using instructional technology leads to higher levels of student learning?" this report examines research indicating that computer technology can improve student achievement when properly implemented. It identifies four principles that guide effective technology integration and examines…

  18. Leadership Issues: Raising Achievement.

    ERIC Educational Resources Information Center

    Horsfall, Chris, Ed.

    This document contains five papers examining the meaning and operation of leadership as a variable affecting student achievement in further education colleges in the United Kingdom. "Introduction" (Chris Horsfall) discusses school effectiveness studies' findings regarding the relationship between leadership and effective schools, distinguishes…

  19. Schools Achieving Gender Equity.

    ERIC Educational Resources Information Center

    Revis, Emma

    This guide is designed to assist teachers presenting the Schools Achieving Gender Equity (SAGE) curriculum for vocational education students, which was developed to align gender equity concepts with the Kentucky Education Reform Act (KERA). Included in the guide are lesson plans for classes on the following topics: legal issues of gender equity,…

  20. The Latino Achievement Gap

    ERIC Educational Resources Information Center

    Madrid, E. Michael

    2011-01-01

    In the very near future, Latino students will become the majority in California's public schools and because of their great numbers and presence, the pattern of lackluster academic achievement must be a major concern of teachers, school leaders, and policy makers. Despite having made great strides in narrowing the gap that separated them from…

  1. Achieving Peace through Education.

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    While it is generally agreed that peace is desirable, there are barriers to achieving a peaceful world. These barriers are classified into three major areas: (1) an erroneous view of human nature; (2) injustice; and (3) fear of world unity. In a discussion of these barriers, it is noted that although the consciousness and conscience of the world…

  2. Schooling and Social Achievement.

    ERIC Educational Resources Information Center

    Kim, Byong-sung; And Others

    Until the 1960s schooling in Korea was looked upon quite favorably as a means of achieving equal social and economic opportunities. In the 1970s, however, many began to raise the question of whether the expansion of educational opportunities really did reduce social inequalities. This report discusses research that analyzes available evidence…

  3. Achieving Sustainability Cindy Carlsson

    E-print Network

    Minnesota, University of

    Achieving Sustainability Cindy Carlsson Mn/DOT Office of Policy Analysis, Research and Innovation April 21, 2011 #12;Sustainability Is Not New Mn/DOT has long been a leader in CSS and environmental excellence. . . . . . so we're well along on the path to sustainability! #12;Today Sustainability is More

  4. Iowa Women of Achievement.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This issue of the Goldfinch highlights some of Iowa's 20th century women of achievement. These women have devoted their lives to working for human rights, education, equality, and individual rights. They come from the worlds of politics, art, music, education, sports, business, entertainment, and social work. They represent Native Americans,…

  5. Learning Achievement Center

    Microsoft Academic Search

    Sharon Dykshoorn

    2002-01-01

    When finds are limited, it is good planning to centralize student instructional support areas whose missions overlap. At Western Iowa Tech Community College several areas including the library, computer lab and the Student Success Center were combined into a single unit, the Learning Achievement Center.

  6. CEBAF accelerator achievements

    SciTech Connect

    Y.C. Chao, M. Drury, C. Hovater, A. Hutton, G.A. Krafft, M. Poelker, C. Reece, M. Tiefenback

    2011-06-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  7. Extensive Nanotwinning: Origin of High Current Density to High Fields in Preform-Optimized Infiltration-Growth-Processed $\\\\hbox{YBa}_{2}\\\\hbox{Cu}_{3}\\\\hbox{O}_{7 - \\\\delta}$ Superconductor

    Microsoft Academic Search

    N. Devendra Kumar; T. Rajasekharan; Ravi C. Gundakaram; Vummethala Seshubai

    2011-01-01

    The origin of high current densities to very high magnetic fields (better than 10 3 A · cm ?2 to 6.5 T at 77 K) in YBa2Cu3O7?? superconductor fabricated by the preform- optimized infiltration-growth process (POIGP) is investigated. The main techniques used in the paper are field-emission scanning electron microscopy and transmission electron microscopy (TEM). An electron-backscattered-diffraction study of the

  8. Faculty achievement tracking tool.

    PubMed

    Pettus, Sarah; Reifschneider, Ellen; Burruss, Nancy

    2009-03-01

    Faculty development and scholarship is an expectation of nurse educators. Accrediting institutions, such as the Commission on Collegiate Nursing Education, the National League for Nursing Accrediting Commission, and the Higher Learning Commission, all have criteria regarding faculty achievement. A faculty achievement tracking tool (FATT) was developed to facilitate documentation of accreditation criteria attainment. Based on criteria from accrediting organizations, the roles that are addressed include scholarship, service, and practice. Definitions and benchmarks for the faculty as an aggregate are included. Undergoing reviews from different accrediting organizations, the FATT has been used once for accreditation of the undergraduate program and once for accreditation of the graduate program. The FATT is easy to use and has become an excellent adjunct for the preparation for accreditation reports. In addition, the FATT may be used for yearly evaluations, advancement, and merit. PMID:19297967

  9. Project ACHIEVE final report

    SciTech Connect

    NONE

    1997-06-13

    Project ACHIEVE was a math/science academic enhancement program aimed at first year high school Hispanic American students. Four high schools -- two in El Paso, Texas and two in Bakersfield, California -- participated in this Department of Energy-funded program during the spring and summer of 1996. Over 50 students, many of whom felt they were facing a nightmare future, were given the opportunity to work closely with personal computers and software, sophisticated calculators, and computer-based laboratories -- an experience which their regular academic curriculum did not provide. Math and science projects, exercises, and experiments were completed that emphasized independent and creative applications of scientific and mathematical theories to real world problems. The most important outcome was the exposure Project ACHIEVE provided to students concerning the college and technical-field career possibilities available to them.

  10. Junior Achievement Student Center

    NSDL National Science Digital Library

    Junior Achievement is an organization that is more than 90 years old and "dedicated to educating students about workforce readiness, entrepreneurship and financial literacy through experiential, hands-on programs." The Junior Achievement Student Center website focuses on "money management", "work readiness", and "business ownership". Visitors can play online "Games", such as "JA Titan", "JA Banks in Action", "JA Money Might", and JA Count on It". "JA Titan" promotes the visitor to CEO of a business, and tests the skills needed to defeat competitors; "JA Money Might" tests financial skills in an online simulation of real life situations. The "Learn" tab teaches visitors about "Money", "Work", "Business", and "The Economy". There is also an "Ethics" section in the "Learn" tab, and it includes 40 downloadable classroom activities, a case study, and an essay contest.

  11. Does achievement motivation mediate the semantic achievement priming effect?

    PubMed

    Engeser, Stefan; Baumann, Nicola

    2014-10-01

    The aim of our research was to understand the processes of the prime-to-behavior effects with semantic achievement primes. We extended existing models with a perspective from achievement motivation theory and additionally used achievement primes embedded in the running text of excerpts of school textbooks to simulate a more natural priming condition. Specifically, we proposed that achievement primes affect implicit achievement motivation and conducted pilot experiments and 3 main experiments to explore this proposition. We found no reliable positive effect of achievement primes on implicit achievement motivation. In light of these findings, we tested whether explicit (instead of implicit) achievement motivation is affected by achievement primes and found this to be the case. In the final experiment, we found support for the assumption that higher explicit achievement motivation implies that achievement priming affects the outcome expectations. The implications of the results are discussed, and we conclude that primes affect achievement behavior by heightening explicit achievement motivation and outcome expectancies. PMID:24820250

  12. Robust Growth-Optimal Portfolios

    E-print Network

    2014-05-24

    May 24, 2014 ... Real investors have only limited ... sense white noise process, which means that the ambiguity set contains all distributions under ..... 'the slightest acquaintance with problems of analysing economic time series will suggest ...

  13. Achievement Goals and Achievement Emotions: A Meta-Analysis

    ERIC Educational Resources Information Center

    Huang, Chiungjung

    2011-01-01

    This meta-analysis synthesized 93 independent samples (N = 30,003) in 77 studies that reported in 78 articles examining correlations between achievement goals and achievement emotions. Achievement goals were meaningfully associated with different achievement emotions. The correlations of mastery and mastery approach goals with positive achievement…

  14. Target Feasibility Achievement in Enterprise-Driven Hierarchical Multidisciplinary Design

    E-print Network

    Papalambros, Panos

    Target Feasibility Achievement in Enterprise-Driven Hierarchical Multidisciplinary Design Harrison optimization, enterprise-driven design, analytical target cascading, discrete choice analysis, multinomial logit demand model, disconnected feasible domain. I. Introduction Designing a large-scale artifact

  15. Prospective Optimization

    PubMed Central

    Sejnowski, Terrence J.; Poizner, Howard; Lynch, Gary; Gepshtein, Sergei; Greenspan, Ralph J.

    2014-01-01

    Human performance approaches that of an ideal observer and optimal actor in some perceptual and motor tasks. These optimal abilities depend on the capacity of the cerebral cortex to store an immense amount of information and to flexibly make rapid decisions. However, behavior only approaches these limits after a long period of learning while the cerebral cortex interacts with the basal ganglia, an ancient part of the vertebrate brain that is responsible for learning sequences of actions directed toward achieving goals. Progress has been made in understanding the algorithms used by the brain during reinforcement learning, which is an online approximation of dynamic programming. Humans also make plans that depend on past experience by simulating different scenarios, which is called prospective optimization. The same brain structures in the cortex and basal ganglia that are active online during optimal behavior are also active offline during prospective optimization. The emergence of general principles and algorithms for goal-directed behavior has consequences for the development of autonomous devices in engineering applications. PMID:25328167

  16. Prospective Optimization.

    PubMed

    Sejnowski, Terrence J; Poizner, Howard; Lynch, Gary; Gepshtein, Sergei; Greenspan, Ralph J

    2014-05-01

    Human performance approaches that of an ideal observer and optimal actor in some perceptual and motor tasks. These optimal abilities depend on the capacity of the cerebral cortex to store an immense amount of information and to flexibly make rapid decisions. However, behavior only approaches these limits after a long period of learning while the cerebral cortex interacts with the basal ganglia, an ancient part of the vertebrate brain that is responsible for learning sequences of actions directed toward achieving goals. Progress has been made in understanding the algorithms used by the brain during reinforcement learning, which is an online approximation of dynamic programming. Humans also make plans that depend on past experience by simulating different scenarios, which is called prospective optimization. The same brain structures in the cortex and basal ganglia that are active online during optimal behavior are also active offline during prospective optimization. The emergence of general principles and algorithms for goal-directed behavior has consequences for the development of autonomous devices in engineering applications. PMID:25328167

  17. Polyethylene fiber drawing optimization

    E-print Network

    Chiloyan, Vazrik

    2011-01-01

    Polymer fiber drawing creates fibers with enhanced thermal conductivity and strength compared to bulk polymer because drawing aligns the molecular chains. I optimize the polymer fiber drawing method in order to achieve ...

  18. Achieving tight glycaemic control.

    PubMed

    Ball, Carol; de Beer, Karen; Gomm, Amanda; Hickman, Barbara; Collins, Peta

    2007-06-01

    The implementation of tight glycaemic control (TGC) is becoming accepted best practice within intensive care units throughout the world. It is recommended by the Surviving Sepsis Campaign and is included in the sepsis care bundle. The major impact of TGC is currently thought to be associated with reduced morbidity and mortality. The process of achieving TGC is, however, not without risk. In particular, the need for frequent, accurate blood glucose measurement and the possibility of prolonged, unrecognised hypoglycaemia are of concern. There is also the potential for patients who exhibit significant insulin resistance to require the administration of large amounts of insulin. The transfer of patients from the intensive care unit to the operating theatre or for computerised tomography during intensive insulin therapy is also hazardous. The purpose of this paper is to describe a series of nurse led pilot studies which aimed to introduce the process of TGC whilst maintaining patient safety. The results demonstrate the effectiveness of a staged approach and the achievement of TGC. PMID:17218100

  19. Academy of Achievement

    NSDL National Science Digital Library

    Letâ??s face it: economia to those great heroes of the past are nothing new, and some might believe that there are too many out there in the first place. The Academy of Achievement website disproves this idea with its well-thought out tributes to those truly unique individuals who have made substantive contributions in the arts, the sciences, and a number of other areas of human endeavor. As its site notes, it is a â??museum of living historyâ?, and a cursory glance over those they have honored would seem to bear witness to this statement. First-time visitors will definitely want to take a look at the â??Achiever Galleryâ?, where they can view profiles and biographies of such personages as Jonas Salk, Rosa Parks, and Willie Mays. The real icing on the cake here is the interview section for each profiled member, as it truly allows for a number of interesting and evocative insights into their motivations and life trajectories. The site is rounded out with a â??For Teachersâ? section, which offers a number of pedagogical tools specifically aimed towards those in the teaching profession.

  20. Growth inhibition of HeLa cells is a conserved feature of high-risk human papillomavirus E8^E2C proteins and can also be achieved by an artificial repressor protein.

    PubMed

    Fertey, Jasmin; Hurst, José; Straub, Elke; Schenker, Astrid; Iftner, Thomas; Stubenrauch, Frank

    2011-03-01

    Infections with certain human papillomaviruses (HPV), such as type 16 (HPV16), 18, or 31, are a necessary risk factor for the development of cervical cancer. Transcript analyses of several HPV revealed that the viral E2 gene encodes both the E2 regulator protein and the E8?E2C protein, which differ in their amino termini. Up to now, functional studies have focused on HPV31 E8?E2C and demonstrated that it is a potent repressor of viral transcription and replication. However, recent analyses of HPV16 genomes have suggested that E8?E2C proteins may differ in their activities. Therefore, we performed a comparative analysis of E8?E2C proteins of HPV16, -18, and -31. All E8?E2C proteins potently inhibited HPV E6/E7 oncogene promoters, and also displayed long-distance transcriptional-repression activities. Furthermore, the expression of all E8?E2C proteins inhibited the growth of HeLa cells. Expression of E8?E2C proteins rapidly increased the protein levels of the E6 and E7 targets p53 and p21, consistent with the repression of the endogenous HPV18 E6/E7 promoter. All E8?E2C proteins induced G(1) arrest more efficiently than E2 proteins and activated senescence markers. Furthermore, we demonstrate that the 31E8 domain can be functionally replaced by the KRAB repression domain derived from KOX1. The KRAB-E2C fusion protein possesses long-distance transcriptional-repression activity and inhibits the growth of HeLa cells comparably to E8?E2C. Taken together, our results suggest that the E8?E2C proteins of HPV16, -18, and -31 are highly conserved transcriptional repressors that inhibit the growth of HeLa cells by repression of E6/E7 transcription but do not have proapoptotic activities. PMID:21191025

  1. Expert system for controlling plant growth in a contained environment

    NASA Technical Reports Server (NTRS)

    May, George A. (Inventor); Lanoue, Mark Allen (Inventor); Bethel, Matthew (Inventor); Ryan, Robert E. (Inventor)

    2009-01-01

    In a system for optimizing crop growth, vegetation is cultivated in a contained environment, such as a greenhouse, an underground cavern or other enclosed space. Imaging equipment is positioned within or about the contained environment, to acquire spatially distributed crop growth information, and environmental sensors are provided to acquire data regarding multiple environmental conditions that can affect crop development. Illumination within the contained environment, and the addition of essential nutrients and chemicals are in turn controlled in response to data acquired by the imaging apparatus and environmental sensors, by an ''expert system'' which is trained to analyze and evaluate crop conditions. The expert system controls the spatial and temporal lighting pattern within the contained area, and the timing and allocation of nutrients and chemicals to achieve optimized crop development. A user can access the ''expert system'' remotely, to assess activity within the growth chamber, and can override the ''expert system''.

  2. Expert system for controlling plant growth in a contained environment

    NASA Technical Reports Server (NTRS)

    May, George A. (Inventor); Lanoue, Mark Allen (Inventor); Bethel, Matthew (Inventor); Ryan, Robert E. (Inventor)

    2011-01-01

    In a system for optimizing crop growth, vegetation is cultivated in a contained environment, such as a greenhouse, an underground cavern or other enclosed space. Imaging equipment is positioned within or about the contained environment, to acquire spatially distributed crop growth information, and environmental sensors are provided to acquire data regarding multiple environmental conditions that can affect crop development. Illumination within the contained environment, and the addition of essential nutrients and chemicals are in turn controlled in response to data acquired by the imaging apparatus and environmental sensors, by an "expert system" which is trained to analyze and evaluate crop conditions. The expert system controls the spatial and temporal lighting pattern within the contained area, and the timing and allocation of nutrients and chemicals to achieve optimized crop development. A user can access the "expert system" remotely, to assess activity within the growth chamber, and can override the "expert system".

  3. Distributive Politics and Economic Growth

    Microsoft Academic Search

    Alberto Alesina

    1994-01-01

    We study the relationship between politics and economic growth in a simple model of endogenous growth with distributive conflict among agents endowed with varying capital\\/labor shares. We establish several results regarding the factor ownership of the median individual and the level of taxation, redistribution, and growth. Policies that maximize growth are optimal only for a government that cares solely about

  4. RF Gun optimization study

    Microsoft Academic Search

    A. Hofler; Pavel Evtushenko; M. Krasilnikov

    2007-01-01

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development

  5. Assisting Pupils in Mathematics Achievement (The Common Core Standards)

    ERIC Educational Resources Information Center

    Ediger, Marlow

    2011-01-01

    Mathematics teachers must expect reasonably high standards of achievement from pupils. Too frequently, pupils attain at a substandard level and more optimal achievement is necessary. Thus, pupils should have self esteem needs met in the school and classroom setting. Thus, learners feel that mathematics is worthwhile and effort must be put forth to…

  6. Schools, Achievement, and Inequality: A Seasonal Perspective

    Microsoft Academic Search

    Karl L. Alexander; Doris R. Entwisle; Linda S. Olson

    2001-01-01

    Are there socioeconomic differences in the seasonality of children’s learning over the school year and summer months? The achievement gap across social lines increases during the primary grades, as much research indicates, but descriptive analyses and HLM within-person growth models for a representative panel of Baltimore school children demonstrate that the increase can be traced mainly to the out-of-school environment

  7. The Homogeneity of School Achievement.

    ERIC Educational Resources Information Center

    Cahan, Sorel

    Since the measurement of school achievement involves the administration of achievement tests to various grades on various subjects, both grade level and subject matter contribute to within-school achievement variations. To determine whether achievement test scores vary most among different fields within a grade level, or within fields among…

  8. Advanced dendritic web growth development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.

    1984-01-01

    Computer specifications for low stress dendritic crystal web growth configurations having thermal elements in fixed positions were developed, as well as computer specifications for web growth incorporating dynamic positioning of thermal elements. Low buckling stress with increased width of unbuckled growth was sought, as well as increased growth velocity while maintaining low residual stress. Model-defined advanced concepts for web growth configurations were defined and verified in experimental web growth. Major increases were achieved in width and velocity.

  9. An attempt to optimize potassium sorbate use to preserve low pH (4.5-5.5) intermediate moisture bakery products by modelling Eurotium spp., Aspergillus spp. and Penicillium corylophilum growth.

    PubMed

    Guynot, M Elena; Marín, Sonia; Sanchis, Vicente; Ramos, Antonio J

    2005-05-25

    Mould growth was modelled on fermented bakery product analogues (FBPA) of two different pH (4.5 and 5.5), different water activity (a(w)) levels (0.80-0.90) and potassium sorbate concentrations (0-0.3%) by using seven moulds commonly causing spoilage of bakery products (Eurotium spp., Aspergillus spp. and Penicillium corylophilum). For the description of fungal growth (growth rates) as a function of a(w), potassium sorbate concentration and pH, 10-terms polynomial models were developed. Modelling enables prediction of spoilage during storage as a function of the factors affecting fungal growth. At pH 4.5 the concentration of potassium sorbate could be reduced to some extent only at low levels of a(w), whereas at pH 5.5 fungal growth was observed even by adding 0.3% of potassium sorbate. However, this preservative could be a valuable alternative as antifungal in such bakery product, of slightly acidic pH, if a long shelf life has not to be achieved. PMID:15862879

  10. HEPEX - achievements and challenges!

    NASA Astrophysics Data System (ADS)

    Pappenberger, Florian; Ramos, Maria-Helena; Thielen, Jutta; Wood, Andy; Wang, Qj; Duan, Qingyun; Collischonn, Walter; Verkade, Jan; Voisin, Nathalie; Wetterhall, Fredrik; Vuillaume, Jean-Francois Emmanuel; Lucatero Villasenor, Diana; Cloke, Hannah L.; Schaake, John; van Andel, Schalk-Jan

    2014-05-01

    HEPEX is an international initiative bringing together hydrologists, meteorologists, researchers and end-users to develop advanced probabilistic hydrological forecast techniques for improved flood, drought and water management. HEPEX was launched in 2004 as an independent, cooperative international scientific activity. During the first meeting, the overarching goal was defined as: "to develop and test procedures to produce reliable hydrological ensemble forecasts, and to demonstrate their utility in decision making related to the water, environmental and emergency management sectors." The applications of hydrological ensemble predictions span across large spatio-temporal scales, ranging from short-term and localized predictions to global climate change and regional modeling. Within the HEPEX community, information is shared through its blog (www.hepex.org), meetings, testbeds and intercompaison experiments, as well as project reportings. Key questions of HEPEX are: * What adaptations are required for meteorological ensemble systems to be coupled with hydrological ensemble systems? * How should the existing hydrological ensemble prediction systems be modified to account for all sources of uncertainty within a forecast? * What is the best way for the user community to take advantage of ensemble forecasts and to make better decisions based on them? This year HEPEX celebrates its 10th year anniversary and this poster will present a review of the main operational and research achievements and challenges prepared by Hepex contributors on data assimilation, post-processing of hydrologic predictions, forecast verification, communication and use of probabilistic forecasts in decision-making. Additionally, we will present the most recent activities implemented by Hepex and illustrate how everyone can join the community and participate to the development of new approaches in hydrologic ensemble prediction.

  11. SOA Executive Overview Achieve Business Agility, October 23, 2012

    E-print Network

    Shahriar, Selim

    1 1 SOA Executive Overview Achieve Business Agility, October 23, 2012 Ray Daniel, Connectivity extent Agile businesses have: · 40% higher EPS growth · 45% higher ROI · 10% faster revenue growth · 2.6X for Business Value 2010 Global CEO Study CEOs Know Their Businesses Must Be More Agile Source: 2010 Convergence

  12. Optimization of air-assisted CVD growth of vertically-aligned ZnO nanowires, guided by structural analysis using X-ray scattering

    NASA Astrophysics Data System (ADS)

    Ok, Jong G.; Hart, A. John

    2009-03-01

    ZnO nanowires (ZNWs) are of significant interest for applications ranging from optical sensors to vibrational energy harvesters, due to properties including UV photoluminescence and piezoelectricity. We have studied low-pressure growth of ZNWs using a vapor transport method in air flowing within a tube furnace, giving vertically-aligned ZNW arrays on sapphire substrates seeded by Au catalysts. The growth rate and the average length of ZNWs depend on the flow rate of air and the total growth time, while multiple parameters such as catalyst thickness, pressure, and temperature also interdependently affect the ZNW characteristics. Grazing incidence small-angle X-ray scattering (GI-SAXS) measurements enable non-destructive quantification of ZNW diameter and alignment. By fitting GI-SAXS images using analytical models of the array as a population of solid cylinders having a Gaussian diameter distribution, we establish precise relationships between the structural characteristics and the growth conditions; for example, we determine rates of radial growth and size distribution broadening in comparison to axial growth. Control of the temperature gradient within the furnace also enables growth of well-aligned arrays at substrate temperatures as low as 600 ^oC.

  13. The Impact of Reading Achievement on Overall Academic Achievement

    ERIC Educational Resources Information Center

    Churchwell, Dawn Earheart

    2009-01-01

    This study examined the relationship between reading achievement and achievement in other subject areas. The purpose of this study was to determine if there was a correlation between reading scores as measured by the Standardized Test for the Assessment of Reading (STAR) and academic achievement in language arts, math, science, and social studies…

  14. Predicting Mathematics Achievement: The Influence of Prior Achievement and Attitudes

    ERIC Educational Resources Information Center

    Hemmings, Brian; Grootenboer, Peter; Kay, Russell

    2011-01-01

    Achievement in mathematics is inextricably linked to future career opportunities, and therefore, understanding those factors that influence achievement is important. This study sought to examine the relationships among attitude towards mathematics, ability and mathematical achievement. This examination was also supported by a focus on gender…

  15. Autoimmune control of lesion growth in CNS with minimal damage

    NASA Astrophysics Data System (ADS)

    Mathankumar, R.; Mohan, T. R. Krishna

    2013-07-01

    Lesions in central nervous system (CNS) and their growth leads to debilitating diseases like Multiple Sclerosis (MS), Alzheimer's etc. We developed a model earlier [1, 2] which shows how the lesion growth can be arrested through a beneficial auto-immune mechanism. We compared some of the dynamical patterns in the model with different facets of MS. The success of the approach depends on a set of control parameters and their phase space was shown to have a smooth manifold separating the uncontrolled lesion growth region from the controlled. Here we show that an optimal set of parameter values exist in the model which minimizes system damage while, at once, achieving control of lesion growth.

  16. Achieving Developmental Synchrony in Young Children With Hearing Loss

    PubMed Central

    Mellon, Nancy K.; Ouellette, Meredith; Greer, Tracy; Gates-Ulanet, Patricia

    2009-01-01

    Children with hearing loss, with early and appropriate amplification and intervention, demonstrate gains in speech, language, and literacy skills. Despite these improvements many children continue to exhibit disturbances in cognitive, behavioral, and emotional control, self-regulation, and aspects of executive function. Given the complexity of developmental learning, educational settings should provide services that foster the growth of skills across multiple dimensions. Transdisciplinary intervention services that target the domains of language, communication, psychosocial functioning, motor, and cognitive development can promote academic and social success. Educational programs must provide children with access to the full range of basic skills necessary for academic and social achievement. In addition to an integrated curriculum that nurtures speech, language, and literacy development, innovations in the areas of auditory perception, social emotional learning, motor development, and vestibular function can enhance student outcomes. Through ongoing evaluation and modification, clearly articulated curricular approaches can serve as a model for early intervention and special education programs. The purpose of this article is to propose an intervention model that combines best practices from a variety of disciplines that affect developmental outcomes for young children with hearing loss, along with specific strategies and approaches that may help to promote optimal development across domains. Access to typically developing peers who model age-appropriate skills in language and behavior, small class sizes, a co-teaching model, and a social constructivist perspective of teaching and learning, are among the key elements of the model. PMID:20150187

  17. ACHIEVING AN OPTIMAL BALANCE OF CENTRALIZATION AND DECENTRALIZATION IN EDUCATION

    Microsoft Academic Search

    Brian J. Caldwell

    This paper draws mainly from experience in the West where there have been changes in the balance of centralization and decentralization in efforts to enhance the quality of education. Particular attention is given to school autonomy (school-based management), school choice and a private role in the management of public education. Successful experience is analysed and guidelines are formulated to assist

  18. Earning the Stamp of Approval: How To Achieve Optimal Usability.

    ERIC Educational Resources Information Center

    Makar, Susan

    2003-01-01

    Describes the redesign of the Web site at the virtual library of the NIST (National Institute of Standards and Technology). Discusses usability problems with the original site, including navigation difficulties; focus groups to determine user needs; usability testing for the new Web site; and the importance of customer input. (LRW)

  19. Achieving optimal fines for political bribery: A suggested political reform

    Microsoft Academic Search

    Velma Montoya Thompson; Earl A. Thompson

    1993-01-01

    Allowing appropriately high fines for political bribery would eliminate: (1) the large and allocatively arbitrary bribes paid to our most senior, retiring, politicians (2) the more moderate, but ubiquitous and still allocatively arbitrary bribes paid to less senior, but strategically successful, politicians, and (3) the permanent loss, through censure or expulsion, of some highly proficient, but strategically less successful, legislative

  20. Convergence Guarantees for a Decentralized Algorithm Achieving Pareto Optimality

    E-print Network

    Baras, John S.

    Park, MD 20742, USA amenon@umd.edu, baras@umd.edu interactions between different wind turbines. By scheduling a certain noise parameter to go to zero along iterations of this algorithm, conditions, consider the problem of maximizing the total power production of a wind farm [8]. Aerodynamic Research

  1. Optimizing Production of Hydroquinone Achieves Increased Yield and Energy Efficiency

    E-print Network

    Gross, S.

    8 9 10 11 12 13 14 15 16 Y i e l d ? ( % ) P r o d u c t i o n ? R a t e Week HQ?Production:?2008?and?2009 2008?Prod?Rate 2009?Prod?Rate 2008?Yield 2009?Yield Results ? Basis of comparison ? Yield Improvement: compared... Saved in 2008 (MMBtu/Yr.) Annualized Net CO2 And Other GHG Emissions Reduction (Tons CO2 or CO2 Equiv) Jan 2009 16% 105,758 11,000 ? Control plan ? Strong control plan essential for holding the gain and retaining knowledge. ? Documented...

  2. Optimization Online - Achieving Cost-Effective Power Grid ...

    E-print Network

    Wei Yuan

    2014-12-29

    Dec 29, 2014 ... ... existing research often employs defender-attacker-defender (DAD) models to derive effective protection plans and evaluate ... Category 1: Applications -- Science and Engineering. Category 2: Other Topics (Game Theory ).

  3. Achieving Better Building Performance and Savings Using Optimal Control Strategies

    E-print Network

    Chen, H.; Deng, S.; Bruner, H.

    2003-01-01

    cooling requirements of the building during occupied hours. The second 280-ton chiller is for redundancy in case one chiller experiences mechanical failure. The 30-ton air- cooled McQuay chiller (Chiller #3) is used primarily to cool the building... during unoccupied hours and when the building cooling load is low. Along with the chillers there are also three (3) parallel chilled water pumps (2? 20 hp and 1x1.5 hp) and two (2) parallel heating water pumps (2? 5 hp). The chilled water pumps...

  4. Achievement as Resistance: The Development of a Critical Race Achievement Ideology among Black Achievers

    ERIC Educational Resources Information Center

    Carter, Dorinda J.

    2008-01-01

    In this article, Dorinda Carter examines the embodiment of a critical race achievement ideology in high-achieving black students. She conducted a yearlong qualitative investigation of the adaptive behaviors that nine high-achieving black students developed and employed to navigate the process of schooling at an upper-class, predominantly white,…

  5. Growth, structural and optical transport properties of nanocrystal Zn 1? x CdS thin films deposited by solution growth technique (SGT) for photosensor applications

    Microsoft Academic Search

    S. Chavhan; R. P. Sharma

    2005-01-01

    Solution Growth Technique (SGT) has been used for deposition of Zn1?xCdS nanocrystalline thin films. Various parameters such as solution pH (10.4), deposition time, concentration of ions, composition and deposition and annealing temperatures have been optimized for the development of device grade thin film. In order to achieve uniformity and adhesiveness of thin film on glass substrate, 5ml triethanolamine (TEA) have

  6. Gender Difference in Insulin-Like Growth Factor I Response to Growth Hormone (GH) Treatment in GH-Deficient Adults: Role of Sex Hormone Replacement

    Microsoft Academic Search

    A. G. H. SMALS

    GH production in healthy women is about thrice that in men. Yet insulin-like growth factor I (IGF-I) levels are similar, suggesting a lower responsivity to GH in women. In untreated GH-deficient adults, basal IGF-I levels are reportedly lower in females than in males, and the therapeutic recombinant human GH (rhGH) dose required to achieve optimal IGF-I levels is higher in

  7. Harming the best: How schools affect the black-white achievement gap

    Microsoft Academic Search

    Eric A. Hanushek; Steven G. Rivkin

    2009-01-01

    Sizeable achievement differences by race appear in early grades, but substantial uncertainty exists about the impact of school quality on the black-white achievement gap and particularly about its evolution across different parts of the achievement distribution. Texas administrative data show that the overall growth in the achievement gap between third and eighth grades is larger for students with higher initial

  8. Review of "High-Achieving Students in the Era of NCLB"

    ERIC Educational Resources Information Center

    Camilli, Gregory

    2008-01-01

    A recent report from the Fordham Institute considers potential instructional policies for high-achieving students that should be considered in the forthcoming reauthorization of the No Child Left Behind Act. The report finds: 1) achievement growth among high-achieving students has been slower than that of low-achieving students; 2) this trend can…

  9. Taurine supplementation of plant derived protein 1 and n-3 fatty acids are critical for optimal growth and development of cobia, rachycentron canadum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined growth performance and lipid content in juvenile cobia, Rachycentron canadum, fed a taurine supplemented (1.5%), plant protein based diet with two fish oil replacements. The first fish oil replacement was a thraustochytrid meal (TM+SOY) plus soybean oil (~9% CL) and the second was a cano...

  10. Optimization of CaC12, MgS04 and KH2P04 to improve the growth of micropropagated red raspberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The amount of genetic variation in red raspberries makes it difficult to successfully apply a standard in vitro growth medium to all cultivars and selections. Murashige and Skoog medium (MS) is commonly used for commercial red raspberry cultivar micropropagation. However, many cultivars grown on MS ...

  11. Excellence in Social Achievement, Affective Learning, Academic Growth.

    ERIC Educational Resources Information Center

    Los Nietos Elementary School District, CA.

    The Los Nietos Basic Skills Program was the first program of computer assisted instruction funded by the Emergency School Aid Act (ESAA). The system initially supported 17 typewriter-style terminals, but the number was later increased to 24. Because of software problems, the system changed companies and the courses changed to the following:…

  12. Environmental optimal control strategies based on plant canopy photosynthesis responses and greenhouse climate model

    NASA Astrophysics Data System (ADS)

    Deng, Lujuan; Xie, Songhe; Cui, Jiantao; Liu, Tao

    2006-11-01

    It is the essential goal of intelligent greenhouse environment optimal control to enhance income of cropper and energy save. There were some characteristics such as uncertainty, imprecision, nonlinear, strong coupling, bigger inertia and different time scale in greenhouse environment control system. So greenhouse environment optimal control was not easy and especially model-based optimal control method was more difficult. So the optimal control problem of plant environment in intelligent greenhouse was researched. Hierarchical greenhouse environment control system was constructed. In the first level data measuring was carried out and executive machine was controlled. Optimal setting points of climate controlled variable in greenhouse was calculated and chosen in the second level. Market analysis and planning were completed in third level. The problem of the optimal setting point was discussed in this paper. Firstly the model of plant canopy photosynthesis responses and the model of greenhouse climate model were constructed. Afterwards according to experience of the planting expert, in daytime the optimal goals were decided according to the most maximal photosynthesis rate principle. In nighttime on plant better growth conditions the optimal goals were decided by energy saving principle. Whereafter environment optimal control setting points were computed by GA. Compared the optimal result and recording data in real system, the method is reasonable and can achieve energy saving and the maximal photosynthesis rate in intelligent greenhouse

  13. Hybrid swarm intelligence optimization approach for optimal data storage position identification in wireless sensor networks.

    PubMed

    Mohanasundaram, Ranganathan; Periasamy, Pappampalayam Sanmugam

    2015-01-01

    The current high profile debate with regard to data storage and its growth have become strategic task in the world of networking. It mainly depends on the sensor nodes called producers, base stations, and also the consumers (users and sensor nodes) to retrieve and use the data. The main concern dealt here is to find an optimal data storage position in wireless sensor networks. The works that have been carried out earlier did not utilize swarm intelligence based optimization approaches to find the optimal data storage positions. To achieve this goal, an efficient swam intelligence approach is used to choose suitable positions for a storage node. Thus, hybrid particle swarm optimization algorithm has been used to find the suitable positions for storage nodes while the total energy cost of data transmission is minimized. Clustering-based distributed data storage is utilized to solve clustering problem using fuzzy-C-means algorithm. This research work also considers the data rates and locations of multiple producers and consumers to find optimal data storage positions. The algorithm is implemented in a network simulator and the experimental results show that the proposed clustering and swarm intelligence based ODS strategy is more effective than the earlier approaches. PMID:25734182

  14. Hybrid Swarm Intelligence Optimization Approach for Optimal Data Storage Position Identification in Wireless Sensor Networks

    PubMed Central

    Mohanasundaram, Ranganathan; Periasamy, Pappampalayam Sanmugam

    2015-01-01

    The current high profile debate with regard to data storage and its growth have become strategic task in the world of networking. It mainly depends on the sensor nodes called producers, base stations, and also the consumers (users and sensor nodes) to retrieve and use the data. The main concern dealt here is to find an optimal data storage position in wireless sensor networks. The works that have been carried out earlier did not utilize swarm intelligence based optimization approaches to find the optimal data storage positions. To achieve this goal, an efficient swam intelligence approach is used to choose suitable positions for a storage node. Thus, hybrid particle swarm optimization algorithm has been used to find the suitable positions for storage nodes while the total energy cost of data transmission is minimized. Clustering-based distributed data storage is utilized to solve clustering problem using fuzzy-C-means algorithm. This research work also considers the data rates and locations of multiple producers and consumers to find optimal data storage positions. The algorithm is implemented in a network simulator and the experimental results show that the proposed clustering and swarm intelligence based ODS strategy is more effective than the earlier approaches. PMID:25734182

  15. How much detail and accuracy is required in plant growth sub-models to address questions about optimal management strategies in agricultural systems?

    PubMed Central

    Renton, Michael

    2011-01-01

    Background and aims Simulations that integrate sub-models of important biological processes can be used to ask questions about optimal management strategies in agricultural and ecological systems. Building sub-models with more detail and aiming for greater accuracy and realism may seem attractive, but is likely to be more expensive and time-consuming and result in more complicated models that lack transparency. This paper illustrates a general integrated approach for constructing models of agricultural and ecological systems that is based on the principle of starting simple and then directly testing for the need to add additional detail and complexity. Methodology The approach is demonstrated using LUSO (Land Use Sequence Optimizer), an agricultural system analysis framework based on simulation and optimization. A simple sensitivity analysis and functional perturbation analysis is used to test to what extent LUSO's crop–weed competition sub-model affects the answers to a number of questions at the scale of the whole farming system regarding optimal land-use sequencing strategies and resulting profitability. Principal results The need for accuracy in the crop–weed competition sub-model within LUSO depended to a small extent on the parameter being varied, but more importantly and interestingly on the type of question being addressed with the model. Only a small part of the crop–weed competition model actually affects the answers to these questions. Conclusions This study illustrates an example application of the proposed integrated approach for constructing models of agricultural and ecological systems based on testing whether complexity needs to be added to address particular questions of interest. We conclude that this example clearly demonstrates the potential value of the general approach. Advantages of this approach include minimizing costs and resources required for model construction, keeping models transparent and easy to analyse, and ensuring the model is well suited to address the question of interest. PMID:22476477

  16. Estimation of the optimal concentrations of residual sugar and cell growth rate for a fed-batch culture of Saccharomyces cerevisiae

    Microsoft Academic Search

    Rong-Qiao He; Chuan-You Li; Jung Xu; Xiu-An Zhao

    1996-01-01

    Estimation of the optimal concentrations of residual sugar in medium for a fed-batch culture of Baker’s yeast has been studied\\u000a and practiced. The concentrations, however, depended on different species and targets of the biomass, which was expected to\\u000a be made. Kinetic changes of the residual phosphate salt in the medium conformed to a logarithmic process until the fourth\\u000a hour during

  17. [Optimization of oxytetracycline biosynthesis].

    PubMed

    Maksimova, E A; Falkov, N N; Izma?lov, N N; Romanchuk, N N

    1988-06-01

    It was shown that rising of temperature up to 30 degrees C at the stage of the oxytetracycline-producing organism growth promoted acceleration of the culture growth rate and increasing of the antibiotic concentration by the 114th hour of the biosynthetic process. For the apparatus used in the study optimal aeration and agitation conditions were developed. To provide optimal parameters during biosynthesis of oxytetracycline, it was recommended to use the aeration rate of 1 v/v.min and the specific mechanical power for mixing of not less than 1 kW/m3. PMID:3421763

  18. Optimizing the water chemistry of the Novovoronezh NPP Units 3 and 4 to prevent growth of coolant pressure difference across the reactor

    NASA Astrophysics Data System (ADS)

    Kritskii, V. G.; Rodionov, Yu. A.; Berezina, I. G.; Zelenina, E. V.; Gavrilov, A. V.; Vitkovskii, S. L.; Shchedrin, M. G.; Galanin, A. V.; Gorburov, V. I.

    2014-02-01

    For a few fuel campaigns in the first years of their extended service life, the Novovoronezh NPP Units 3 and 4 had to operate with a limited reactor thermal power output due to constraints imposed on certain parameters of the reactor core. The decrease of thermal power output during a campaign was accompanied by a growth of pressure difference across the reactor caused by accumulation of deposits in the fuel assemblies, which in turn led to a growth in the number of leaky fuel rods. Compensating measures were implemented based on the results obtained from the performed investigations and modeling of corrosion product mass transfer processes, which in the final analysis made it possible to minimize the accumulation of deposits in fuel assemblies and loss of fuel rod tightness, and to exclude the need to limit the reactor thermal power as demanded by constraints imposed on the reactor core parameters.

  19. Superintendent Tenure and Student Achievement

    ERIC Educational Resources Information Center

    Simpson, Jennifer

    2013-01-01

    A correlational research design was used to examine the influence of superintendent tenure on student achievement in rural Appalachian Kentucky school districts. Superintendent tenure was compared to aggregated student achievement scores for 2011 and to changes in students' learning outcomes over the course of the superintendents' tenure. The…

  20. Stress Correlates and Academic Achievement.

    ERIC Educational Resources Information Center

    Bentley, Donna Anderson; And Others

    An ongoing concern for educators is the identification of factors that contribute to or are associated with academic achievement; one such group of variables that has received little attention are those involving stress. The relationship between perceived sources of stress and academic achievement was examined to determine if reactions to stress…

  1. Raising Boys' Achievement in Schools.

    ERIC Educational Resources Information Center

    Bleach, Kevan, Ed.

    This book offers insights into the range of strategies and good practice being used to raise the achievement of boys. Case studies by school-based practitioners suggest ideas and measures to address the issue of achievement by boys. The contributions are: (1) "Why the Likely Lads Lag Behind" (Kevan Bleach); (2) "Helping Boys Do Better in Their…

  2. Understanding and Fostering Achievement Motivation

    ERIC Educational Resources Information Center

    Klose, Laurie McGarry

    2008-01-01

    Fostering achievement motivation in students is a primary objective of school administrators. A good deal of focus goes to promoting motivation when creating school climate, structuring grading systems, and designing awards programs and policies that recognize effort and achievement. It is also a primary issue in counseling and interventions for…

  3. General Achievement Trends: Rhode Island

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  4. Examination Regimes and Student Achievement

    ERIC Educational Resources Information Center

    Cosentino de Cohen, Clemencia

    2010-01-01

    Examination regimes at the end of secondary school vary greatly intra- and cross-nationally, and in recent years have undergone important reforms often geared towards increasing student achievement. This research presents a comparative analysis of the relationship between examination regimes and student achievement in the OECD. Using a micro…

  5. Teaching the Low Level Achiever.

    ERIC Educational Resources Information Center

    Salomone, Ronald E., Ed.

    1986-01-01

    Intended for teachers of the English language arts, the articles in this issue offer suggestions and techniques for teaching the low level achiever. Titles and authors of the articles are as follows: (1) "A Point to Ponder" (Rachel Martin); (2) "Tracking: A Self-Fulfilling Prophecy of Failure for the Low Level Achiever" (James Christopher Davis);…

  6. The celA Gene, Encoding a Glycosyl Hydrolase Family 3 ?-Glucosidase in Azospirillum irakense, Is Required for Optimal Growth on Cellobiosides

    PubMed Central

    Faure, Denis; Henrissat, Bernard; Ptacek, David; Bekri, My Ali; Vanderleyden, Jos

    2001-01-01

    The CelA ?-glucosidase of Azospirillum irakense, belonging to glycosyl hydrolase family 3 (GHF3), preferentially hydrolyzes cellobiose and releases glucose units from the C3, C4, and C5 oligosaccharides. The growth of a ?celA mutant on these cellobiosides was affected. In A. irakense, the GHF3 ?-glucosidases appear to be functional alternatives for the GHF1 ?-glucosidases in the assimilation of ?-glucosides by other bacteria. PMID:11319128

  7. Optimal adaptive management for the translocation of a threatened species.

    PubMed

    Rout, Tracy M; Hauser, Cindy E; Possingham, Hugh P

    2009-03-01

    Active adaptive management (AAM) is an approach to wildlife management that acknowledges our imperfect understanding of natural systems and allows for some resolution of our uncertainty. Such learning may be characterized by risky strategies in the short term. Experimentation is only considered acceptable if it is expected to be repaid by increased returns in the long term, generated by an improved understanding of the system. By setting AAM problems within a decision theory framework, we can find this optimal balance between achieving our objectives in the short term and learning for the long term. We apply this approach to managing the translocation of the bridled nailtail wallaby (Onychogalea fraenata), an endangered species from Queensland, Australia. Our task is to allocate captive-bred animals, between two sites or populations to maximize abundance at the end of the translocation project. One population, at the original site of occupancy, has a known growth rate. A population potentially could be established at a second site of suitable habitat, but we can only learn the growth rate of this new population by monitoring translocated animals. We use a mathematical programming technique called stochastic dynamic programming, which determines optimal management decisions for every possible management trajectory. We find optimal strategies under active and passive adaptive management, which enables us to examine the balance between learning and managing directly. Learning is more often optimal when we have less prior information about the uncertain population growth rate at the new site, when the growth rate at the original site is low, and when there is substantial time remaining in the translocation project. Few studies outside the area of optimal harvesting have framed AAM within a decision theory context. This is the first application to threatened species translocation. PMID:19323207

  8. High Growth Rate Metal-Organic Molecular Beam Epitaxy for the Fabrication of GaAs Space Solar Cells

    NASA Technical Reports Server (NTRS)

    Freundlich, A.; Newman, F.; Monier, C.; Street, S.; Dargan, P.; Levy, M.

    2005-01-01

    In this work it is shown that high quality GaAs photovoltaic devices can be produced by Molecular Beam Epitaxy (MBE) with growth rates comparable to metal-organic chemical vapor deposition (MOCVD) through the subsitution of group III solid sources by metal-organic compounds. The influence the III/V flux-ratio and growth temperatures in maintaining a two dimensional layer by layer growth mode and achieving high growth rates with low residual background impurities is investigated. Finally subsequent to the study of the optimization of n- and p doping of such high growth rate epilayers, results from a preliminary attempt in the fabrication of GaAs photovoltaic devices such as tunnel diodes and solar cells using the proposed high growth rate approach are reported.

  9. CCMR: Characterizing Growth of Single Cell Amoeba

    NSDL National Science Digital Library

    Yavitt, Ben

    2010-08-15

    This summer, I worked on developing methods and protocols for studying the vegetative growth cycle of the social amoeba Dictyostelium discoideum. With my collaborators, we conducted experiments that optimized our ability to monitor the amoeba’s different growth phases.

  10. Using Design To Achieve Sustainability

    EPA Science Inventory

    Sustainability is defined as meeting the needs of this generation without compromising the ability of future generations to meet their needs. This is a conditional statement that places the responsibility for achieving sustainability squarely in hands of designers and planners....

  11. Behavioral Engagement in Learning and Math Achievement over Kindergarten: A Contextual Analysis

    ERIC Educational Resources Information Center

    Robinson, Keith; Mueller, Anna S.

    2014-01-01

    Using nationally representative data on 12,462 kindergarten children, this report examines the link between behavioral engagement and math achievement growth during kindergarten. Multilevel models show that students with higher individual engagement tend to experience larger math achievement growth over kindergarten, that classroom engagement…

  12. Classroom Order and Student Learning in Late Elementary School: A Multilevel Transactional Model of Achievement Trajectories

    ERIC Educational Resources Information Center

    Gaskins, Clare S.; Herres, Joanna; Kobak, Roger

    2012-01-01

    This study examines the association between classroom order in 4th and 5th grades and student achievement growth over a school year. A three level transactional model tested the effects of classroom order on students' rates of growth in math and reading during the school year controlling for starting achievement levels, student risk factors, and…

  13. Akamai technologies : an analysis of product and platform growth strategies

    E-print Network

    Piper, Victor L. (Victor Lawrence)

    2013-01-01

    Akamai Technologies has achieved market leadership in content delivery and application acceleration services and is pursuing aggressive growth. Akamai has advised the market that growth to $5B by 2020 is achievable by ...

  14. Achieving a vanishing SNR-gap to exact lattice decoding at a subexponential complexity

    E-print Network

    Gesbert, David

    Achieving a vanishing SNR-gap to exact lattice decoding at a subexponential complexity Arun Singh in [1] has revealed that, to achieve a vanishing error-gap to optimal ML solutions, even such branch that achieves, in the general outage-limited MIMO setting and in the high-rate and high-SNR limit, both

  15. Primary Mental Abilities and Metropolitan Readiness Tests as Predictors of Achievement in the First Primary Year.

    ERIC Educational Resources Information Center

    University City School District, MO.

    The prediction of achievement provides teachers with necessary information to help children attain optimal achievement. If some skill prerequistites to learning which are not fully developed can be identified and strengthened, higher levels of achievement may result. The Metropolitan Readiness Tests (MRT) are routinely given to all University City…

  16. Equine herpesvirus 1 gene 12 can substitute for vmw65 in the growth of herpes simplex virus (HSV) type 1, allowing the generation of optimized cell lines for the propagation of HSV vectors with multiple immediate-early gene defects.

    PubMed

    Thomas, S K; Lilley, C E; Latchman, D S; Coffin, R S

    1999-09-01

    Herpes simplex virus (HSV) has often been suggested for development as a vector, particularly for the nervous system. Considerable evidence has shown that for use of HSV as a vector, immediate-early (IE) gene expression must be minimized or abolished, otherwise such vectors are likely to be highly cytotoxic. Mutations of vmw65 which abolish IE promoter transactivating activity may also be included to reduce IE gene expression generally. However, when vmw65 mutations are combined with an IE gene deletion, such viruses are hard to propagate, even on cells which otherwise complement the IE gene deletion effectively. We have found that vmw65 mutants can be effectively grown on cell lines expressing equine herpesvirus 1 gene 12, a non-HSV homologue of vmw65 with little sequence similarity to its HSV counterpart. This prevents repair by homologous recombination of vmw65 mutations in the virus, which would occur if mutations were complemented by vmw65 itself. The gene 12 protein is not packaged into HSV virions, which is important if viruses grown on such cells are to be used as vectors. These results not only further strengthen the evidence for direct functional homology between and similar modes of action of the two proteins but have allowed the generation of gene 12-containing cell lines in which ICP4 and ICP27 expression is induced by virus infection (probably by ICP0) and which give efficient growth of viruses deficient in ICP27, ICP4, and vmw65 (the viruses also have ICP34.5/ORFP deleted). Efficient growth of such viruses has not previously been possible. As these viruses are highly deficient in IE gene expression generally, such virus-cell line combinations may provide an alternative to HSV vectors with deletions of all four of the regulatory IE genes which, for optimal growth, require cell lines containing all four IE genes but which are hard to generate due to the intrinsic cytotoxicity of each of the proteins. PMID:10438830

  17. Equine Herpesvirus 1 Gene 12 Can Substitute for vmw65 in the Growth of Herpes Simplex Virus (HSV) Type 1, Allowing the Generation of Optimized Cell Lines for the Propagation of HSV Vectors with Multiple Immediate-Early Gene Defects

    PubMed Central

    Thomas, S. K.; Lilley, C. E.; Latchman, D. S.; Coffin, R. S.

    1999-01-01

    Herpes simplex virus (HSV) has often been suggested for development as a vector, particularly for the nervous system. Considerable evidence has shown that for use of HSV as a vector, immediate-early (IE) gene expression must be minimized or abolished, otherwise such vectors are likely to be highly cytotoxic. Mutations of vmw65 which abolish IE promoter transactivating activity may also be included to reduce IE gene expression generally. However, when vmw65 mutations are combined with an IE gene deletion, such viruses are hard to propagate, even on cells which otherwise complement the IE gene deletion effectively. We have found that vmw65 mutants can be effectively grown on cell lines expressing equine herpesvirus 1 gene 12, a non-HSV homologue of vmw65 with little sequence similarity to its HSV counterpart. This prevents repair by homologous recombination of vmw65 mutations in the virus, which would occur if mutations were complemented by vmw65 itself. The gene 12 protein is not packaged into HSV virions, which is important if viruses grown on such cells are to be used as vectors. These results not only further strengthen the evidence for direct functional homology between and similar modes of action of the two proteins but have allowed the generation of gene 12-containing cell lines in which ICP4 and ICP27 expression is induced by virus infection (probably by ICP0) and which give efficient growth of viruses deficient in ICP27, ICP4, and vmw65 (the viruses also have ICP34.5/ORFP deleted). Efficient growth of such viruses has not previously been possible. As these viruses are highly deficient in IE gene expression generally, such virus-cell line combinations may provide an alternative to HSV vectors with deletions of all four of the regulatory IE genes which, for optimal growth, require cell lines containing all four IE genes but which are hard to generate due to the intrinsic cytotoxicity of each of the proteins. PMID:10438830

  18. Optimizing a Ratchet Gear

    E-print Network

    I. M. Sokolov

    2002-07-29

    The energetic efficiencies of rocked ratchets reported in the literature typically lie in the sub-percent range. We discuss the problem of optimization of the energetic efficiency of a ratchet, and show that considerably higher efficiencies can be achieved; however this assumes a fine-tuning of the parameters of the system. The domain of parameters corresponding to high efficiencies is typically narrow.

  19. Supply-Chain Optimization Template

    NASA Technical Reports Server (NTRS)

    Quiett, William F.; Sealing, Scott L.

    2009-01-01

    The Supply-Chain Optimization Template (SCOT) is an instructional guide for identifying, evaluating, and optimizing (including re-engineering) aerospace- oriented supply chains. The SCOT was derived from the Supply Chain Council s Supply-Chain Operations Reference (SCC SCOR) Model, which is more generic and more oriented toward achieving a competitive advantage in business.

  20. Combined optimization model for sustainable energization strategy

    NASA Astrophysics Data System (ADS)

    Abtew, Mohammed Seid

    Access to energy is a foundation to establish a positive impact on multiple aspects of human development. Both developed and developing countries have a common concern of achieving a sustainable energy supply to fuel economic growth and improve the quality of life with minimal environmental impacts. The Least Developing Countries (LDCs), however, have different economic, social, and energy systems. Prevalence of power outage, lack of access to electricity, structural dissimilarity between rural and urban regions, and traditional fuel dominance for cooking and the resultant health and environmental hazards are some of the distinguishing characteristics of these nations. Most energy planning models have been designed for developed countries' socio-economic demographics and have missed the opportunity to address special features of the poor countries. An improved mixed-integer programming energy-source optimization model is developed to address limitations associated with using current energy optimization models for LDCs, tackle development of the sustainable energization strategies, and ensure diversification and risk management provisions in the selected energy mix. The Model predicted a shift from traditional fuels reliant and weather vulnerable energy source mix to a least cost and reliable modern clean energy sources portfolio, a climb on the energy ladder, and scored multifaceted economic, social, and environmental benefits. At the same time, it represented a transition strategy that evolves to increasingly cleaner energy technologies with growth as opposed to an expensive solution that leapfrogs immediately to the cleanest possible, overreaching technologies.

  1. Hall of Black Achievement Gallery

    NSDL National Science Digital Library

    A project of Bridgewater State College, the Hall of Black Achievement (HOBA). is a repository of the significant achievements and contributions of African Americans, Cape Verdeans, and Hispanics of African descent. The mission of the HOBA is to "discover, detail, and disclose the significant achievements and contributions of people of color." HOBA also serves as a forum for research, discussion, and analysis of the significant contributions that people of color continue to make to this country and beyond. The Web site now features a gallery of the historical figures inducted into the HOBA and chronicles their lives, contributions, and the period of history in which they lived. Audio narratives can be heard with RealPlayer.

  2. Critical Pedagogy for Transformative Optimism

    ERIC Educational Resources Information Center

    Mayo, Peter

    2006-01-01

    This essay critically highlights the main features of a study that attaches importance to the concepts of time and optimism and their effects on the achievement and goals of high and low achievers in a North American and a Brazilian context. The focus on the time factor that serves as a leitmotif throughout the study gives this work its…

  3. Communicating to Diverse Audiences to Achieve Your Goals

    E-print Network

    Heritage Historical value, future generations, quality of life #12;Put the Data in Context Amt of water? Monitoring results Progress achieved Trends Legislative accomplishments Growth in the organization Kudos #12;#12;#12;#12;Welcome to the Minnesota Land Trust! The Minnesota Land Trust is a private nonprofit organization working

  4. Sociodemographic Moderators of Middle School Transition Effects on Academic Achievement

    ERIC Educational Resources Information Center

    Akos, Patrick; Rose, Roderick A.; Orthner, Dennis

    2015-01-01

    The academic impact of the transition from elementary to middle school has significant consequences for many early adolescents. This study examines academic growth across the transition, as well as sociodemographic moderators. Rather than defining the transition effect as a decline in student achievement between fifth and sixth grade, these data…

  5. Achieving low-carbon economy by disruptive innovation in China

    Microsoft Academic Search

    Zhiwei Wang; Jin Chen

    2008-01-01

    This paper proposes a framework for China to achieve low-carbon economy by disruptive innovations. Chinapsilas rapid industrialization and economic growth have significantly increased its energy consumption. The issue of Greenhouse Gas mitigation poses a huge challenge to China to create an innovative and sustainable development pattern. Both theoretical and empirical studies imply that technological transition approach would be a suitable

  6. Entropy, environment, and endogenous economic growth

    Microsoft Academic Search

    Sjak Smulders

    1995-01-01

    This paper investigates the proper modeling of the interaction between economic growth and environmental problems, summarizes under which conditions unlimited economic growth with limited natural resources is feasible, and describes how sustainable growth can be achieved. It synthesizes the results from various environmental endogenous growth models.

  7. MPQC: Performance Analysis and Optimization

    SciTech Connect

    Sarje, Abhinav; Williams, Samuel; Bailey, David

    2012-11-30

    MPQC (Massively Parallel Quantum Chemistry) is a widely used computational quantum chemistry code. It is capable of performing a number of computations commonly occurring in quantum chemistry. In order to achieve better performance of MPQC, in this report we present a detailed performance analysis of this code. We then perform loop and memory access optimizations, and measure performance improvements by comparing the performance of the optimized code with that of the original MPQC code. We observe that the optimized MPQC code achieves a significant improvement in the performance through a better utilization of vector processing and memory hierarchies.

  8. Teacher Certification and Student Achievement

    ERIC Educational Resources Information Center

    Moss, Patricia Lewis

    2012-01-01

    The purpose of this mixed-method study was to determine if there is a significant difference between the achievement of students who are taught by traditionally prepared teachers and that of students who are taught by alternatively prepared teachers. The study further addressed the perspectives of both groups of teachers regarding selected…

  9. Helping Rural Schools Achieve Success.

    ERIC Educational Resources Information Center

    Collins, Susan

    2003-01-01

    Senator Collins of Maine plans to fight for proper federal funding of the Rural Education Achievement Program (REAP) that allows rural schools to combine federal funding sources. Collins, and Senator Dianne Feinstein, will soon introduce legislation that will eliminate inequities in the current Social Security law that penalize teachers and other…

  10. Mathematics Anxiety and Mathematics Achievement

    Microsoft Academic Search

    Brian F. Sherman; David P. Wither

    2003-01-01

    This paper is a distillation of the major result from the 1998 Ph.D. thesis of the late David Wither. It details a longitudinal study over five years of the relationship between mathematics anxiety and mathematics achievement. It starts from the already well documented negative correlation between the two, and seeks to establish one of the three hypotheses—that mathematics anxiety causes

  11. Academic Achievement in Effective Schools

    ERIC Educational Resources Information Center

    Basque, Marc; Bouchamma, Yamina

    2013-01-01

    Purpose: The purpose of this study is to identify predictors of achievement in mathematics in elementary schools in New Brunswick (Canada). Data Collection: Both teachers and school leaders (N = 111) completed a questionnaire on their practices and on school functioning. Findings: Multiple regression analyses revealed that the students'…

  12. Florida's Fit to Achieve Program.

    ERIC Educational Resources Information Center

    Sander, Allan N.; And Others

    1993-01-01

    Describes Florida's "Fit to Achieve," a cardiovascular fitness education program for elementary students. Children are taught responsibility for their own cardiovascular fitness through proper exercise, personal exercise habits, and regular aerobic exercise. The program stresses collaborative effort between physical educators and classroom…

  13. The Widening Income Achievement Gap

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2013-01-01

    Has the academic achievement gap between high-income and low-income students changed over the last few decades? If so, why? And what can schools do about it? Researcher Sean F. Reardon conducted a comprehensive analysis of research to answer these questions and came up with some striking findings. In this article, he shows that income-related…

  14. The Racial Academic Achievement Gap

    ERIC Educational Resources Information Center

    Green, Toneka M.

    2008-01-01

    Closing the racial academic achievement gap is a problem that must be solved in order for future society to properly function. Minorities including African-American and Latino students' standardized test scores are much lower than white students. By the end of fourth grade, African American, Latino, and poor students of all races are two years…

  15. Reading Achievement and Juvenile Delinquency.

    ERIC Educational Resources Information Center

    Hill, Nancy C.; Atkinson, Tommy

    The reading achievement of 31 male juvenile delinquents was analyzed and compared to previous reading research on similar subjects. The subjects were nine learning disabled students, five emotionally handicapped students, five educable mentally handicapped students, and twelve students who were in the process of being evaluated for special…

  16. Defense economics: achievements and challenges

    Microsoft Academic Search

    Keith Hartley

    2007-01-01

    Defense economics is now an established part of economics. This article reviews its achievements as represented by papers published in the research journal Defense and Peace Economics. The range of topics in the journal is reviewed, especially since 2000, and major gaps in coverage are identified. A changing research agenda reflects new developments such as terrorism and international peacekeeping. Gaps

  17. University Characteristics and Student Achievement.

    ERIC Educational Resources Information Center

    Ayres, Q. Whitfield; Bennett, Ronald W.

    Characteristics of colleges that are related to the achievement of undergraduates in teacher education were studied, based on study of 15 North Carolina institutions, 10 predominantly white and 5 predominantly black public universities. Student performance on the National Teacher Examinations and Scholastic Aptitude Test (SAT) scores were used as…

  18. Can Judges Improve Academic Achievement?

    ERIC Educational Resources Information Center

    Greene, Jay P.; Trivitt, Julie R.

    2008-01-01

    Over the last 3 decades student achievement has remained essentially unchanged in the United States, but not for a lack of spending. Over the same period a myriad of education reforms have been suggested and per-pupil spending has more than doubled. Since the 1990s the education reform attempts have frequently included judicial decisions to revise…

  19. School Desegregation and Black Achievement.

    ERIC Educational Resources Information Center

    Cook, Thomas; And Others

    Seven papers commissioned by the National Institute of Education in order to clarify the state of recent knowledge about the effects of school desegregation on the academic achievement of black students are contained in this report. The papers, which analyze 19 "core" empirical studies on this topic, include: (1) "What Have Black Children Gained…

  20. Socioeconomic Determinants of Academic Achievement

    ERIC Educational Resources Information Center

    Tomul, Ekber; Savasci, Havva Sebile

    2012-01-01

    This study aims to investigate the relationship between academic achievement and the socioeconomic characteristics of elementary school 7th grade students in Burdur. The population of the study are 7th grade students who had education at elementary schools in Burdur in the 2007-2008 academic year. Two staged sampling was chosen as suitable for the…

  1. Washington State's Student Achievement Initiative

    ERIC Educational Resources Information Center

    Pettitt, Maureen; Prince, David

    2010-01-01

    This article describes Washington State's Student Achievement Initiative, an accountability system implemented in 2005-06 that measures students' gains in college readiness, college credits earned, and degree or certificate completion. The goal of the initiative is to increase educational attainment by focusing on the critical momentum points…

  2. Faculty Development: Assessing Learner Achievement.

    ERIC Educational Resources Information Center

    Frey, Barbara A.; Overfield, Karen

    This study addressed the challenges of developing a faculty professional development workshop on assessment, measurement, and evaluation of achievement in adult learners. The setting for the workshop was a system of postsecondary career colleges throughout the United States. The curriculum development model of D. Kirkpatrick (1994) was used as a…

  3. Parametric Design Optimization By Integrating CAD Systems And Optimization Tools

    NASA Astrophysics Data System (ADS)

    Rehan, M.; Olabi, A. G.

    2009-11-01

    Designing a cost effective product in minimum time is a complex process. In order to achieve this goal the requirement of optimum designs are becoming more important. One of the time consuming factor in the design optimization cycle is the modifications of Computer Aided Design (CAD) model after optimization. In conventional design optimization techniques the design engineer has to update the CAD model after receiving optimum design from optimization tools. It is worthwhile using parametric design optimization process to minimize the optimization cycle time. This paper presents a comprehensive study to integrate the optimization parameters between CAD system and optimization tools which were driven from a single user environment. Finally, design optimization of a Compressed Natural Gas (CNG) cylinder was implemented as case study. In this case study the optimization tools were fully integrated with CAD system, therefore, all the deliverables including; part design, drawings and assembly can be automatically updated after achieving the optimum geometry having minimum volume and satisfying all imposed constraints.

  4. 2011 and 2012 Early Careers Achievement Awards: Placental programming: how the maternal environment can impact placental function.

    PubMed

    Vonnahme, K A; Lemley, C O; Shukla, P; O'Rourke, S T

    2013-06-01

    Proper establishment of the placenta is important for fetal survival; however, placental adaptations to inadequate maternal nutrition or other stressors are imperative for fetal growth to be optimal. The effects of maternal nutritional status and activity level on placental vascular function and uteroplacental blood flows are important to understand as improper placental function leads to reduced growth of the fetus. In environments where fetal growth can be compromised, potential therapeutics may augment placental function and delivery of nutrients to improve offspring performance during postnatal life. Factors that could enhance placental function include supplementation of specific nutrients, such as protein, hormone supplements, such as indolamines, and increased activity levels of the dam. To understand the mechanism of how the maternal environment can impact uterine or umbilical blood flows, assessment of placental vascular reactivity has been studied in several large animal models. As we begin to understand how the maternal environment impacts uterine and umbilical blood flows and other uteroplacental hemodynamic parameters, development of management methods and therapeutics for proper fetal growth can be achieved. PMID:23307854

  5. Validation and workflow optimization of human epidermal growth factor receptor 2 testing using INFORM HER2 dual-color in situ hybridization.

    PubMed

    Lim, Sung-Jig; Cantillep, Alegria; Carpenter, Philip M

    2013-11-01

    Human epidermal growth factor receptor 2 (HER2) status is useful for predicting response to trastuzumab. Fluorescence in situ hybridization (FISH) for HER2 gene amplification is accurate but limited because of cost, the need for fluorescence microscopy, the limited assessment of histology, and the fading of its signal over time. Dual-color in situ hybridization (Dual ISH) is fully automated, is viewable by bright-field microscopy, has a stable signal, and has separate colors for HER2 and chromosome 17 signals. HER2 immunohistochemistry (IHC), FISH, and Dual ISH were performed on 101 breast cancer cases. Sixteen of 17 cases with 3+ HER2 by IHC showed gene amplification by FISH, and 15 showed amplification by Dual ISH. Three of the 2+ IHC cases were either amplified or equivocal by Dual ISH. None of the IHC-negative cases were amplified by either FISH or Dual ISH. Dual ISH agreed with FISH in 93% of cases. Among the 6 discrepancies, 4 were for an equivocal result for 1 test compared with either a positive or a negative result for the other test. The average differences in readings between Dual ISH and FISH in the discrepant cases were only 0.02, with a range of -1.37 to 1.85. Turnaround time for FISH as a send-out test from test ordering to reporting averaged 8.27 workdays, whereas the turnaround time for Dual ISH performed in-house averaged 4.94 workdays (P < .0000001). Our results indicated that automated Dual ISH is a useful method for evaluating HER2 status in a clinical setting. PMID:24075600

  6. Export of Vacuolar Manganese by AtNRAMP3 and AtNRAMP4 Is Required for Optimal Photosynthesis and Growth under Manganese Deficiency1[W

    PubMed Central

    Lanquar, Viviane; Ramos, Magali Schnell; Lelièvre, Françoise; Barbier-Brygoo, Hélène; Krieger-Liszkay, Anja; Krämer, Ute; Thomine, Sébastien

    2010-01-01

    Manganese (Mn) is an essential element, acting as cofactor in numerous enzymes. In particular, a Mn cluster is indispensable for the function of the oxygen-evolving complex of photosystem II. Metal transporters of the Natural Resistance-Associated Macrophage Protein (NRAMP) family have the ability to transport both iron and Mn. AtNRAMP3 and AtNRAMP4 are required for iron mobilization in germinating seeds. The results reported here show that, in adult Arabidopsis (Arabidopsis thaliana) plants, AtNRAMP3 and AtNRAMP4 have an important role in Mn homeostasis. Vacuolar Mn accumulation in mesophyll cells of rosette leaves of adult nramp3nramp4 double mutant plants was dramatically increased when compared with the wild type. This suggests that a considerable proportion of the cellular Mn pool passes through the vacuole and is retrieved in an AtNRAMP3/AtNRAMP4-dependent manner. The impaired Mn release from mesophyll vacuoles of nramp3nramp4 double mutant plants is associated with reduced growth under Mn deficiency. However, leaf AtNRAMP3 and AtNRAMP4 protein levels are unaffected by Mn supply. Under Mn deficiency, nramp3nramp4 plants contain less functional photosystem II than the wild type. These data are consistent with a shortage of Mn to produce functional photosystem II, whereas mitochondrial Mn-dependent superoxide dismutase activity is maintained under Mn deficiency in both genotypes. The results presented here suggest an important role for AtNRAMP3/AtNRAMP4-dependent Mn transit through the vacuole prior to the import into chloroplasts of mesophyll cells. PMID:20181755

  7. Sequential growth and monitoring of a polypyrrole actuator system

    NASA Astrophysics Data System (ADS)

    Sarrazin, J. C.; Mascaro, Stephen A.

    2014-03-01

    Electroactive polymers (EAPs) have emerged as viable materials in sensing and actuating applications, but the capability to mimic the structure and function of natural muscle is increased due to their ability to permit additional, sequential synthesis steps between stages of actuation. Current work is improving upon the mechanical performance in terms of achievable stresses, strains, and strain rates, but issues still remain with actuator lifetime and adaptability. This work seeks to create a bioinspired polymer actuation system that can be monitored using state estimation and adjusted in vivo during operation. The novel, time-saving process of sequential growth was applied to polymer actuator systems for the initial growth, as well as additional growth steps after actuation cycles. Synthesis of conducting polymers on a helical metal electrode directs polymer shape change during actuation, assists in charge distribution along the polymer for actuation, and as is described in this work, constructs a constant working electrode/polymer connection during operation which allows sequential polymer growth based on a performance need. The polymer system is monitored by means of a reduced-order, state estimation model that works between growth and actuation cycles. In this case, actuator stress is improved between growth cycles. The ability for additional synthesis of the polymer actuator not only creates an actuator system that can be optimized based on demand, but creates a dynamic actuator system that more closely mimics natural muscle capability.

  8. Physical vapor transport crystal growth

    NASA Technical Reports Server (NTRS)

    Yoel, Dave W.; Anderson, Elmer; Wu, Maw-Kuen; Cheng, H. Y.

    1987-01-01

    The goals of this research are two-fold: to study effective means of growing ZnSe crystals of good optical quality and to determine the advantages of growing such crystals in microgravity. As of this date the optimal conditions for crystal growth have not been determined. However, successful growth runs were made in two furnances and the results are given.

  9. RF Gun Optimization Study

    SciTech Connect

    Alicia Hofler; Pavel Evtushenko

    2007-07-03

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. A genetic algorithm (GA) has been successfully used to optimize DC photo injector designs at Cornell University [1] and Jefferson Lab [2]. We propose to apply GA techniques to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize a system that has been benchmarked with beam measurements and simulation.

  10. Entropy production of a steady-growth cell with catalytic reactions.

    PubMed

    Himeoka, Yusuke; Kaneko, Kunihiko

    2014-10-01

    Cells generally convert external nutrient resources to support metabolism and growth. Understanding the thermodynamic efficiency of this conversion is essential to determine the general characteristics of cellular growth. Using a simple protocell model with catalytic reaction dynamics to synthesize the necessary enzyme and membrane components from nutrients, the entropy production per unit-cell-volume growth is calculated analytically and numerically based on the rate equation for chemical kinetics and linear nonequilibrium thermodynamics. The minimal entropy production per unit-cell growth is found to be achieved at a nonzero nutrient uptake rate rather than at a quasistatic limit as in the standard Carnot engine. This difference appears because the equilibration mediated by the enzyme exists only within cells that grow through enzyme and membrane synthesis. Optimal nutrient uptake is also confirmed by protocell models with many chemical components synthesized through a catalytic reaction network. The possible relevance of the identified optimal uptake to optimal yield for cellular growth is also discussed. PMID:25375530

  11. Entropy production of a steady-growth cell with catalytic reactions

    E-print Network

    Yusuke Himeoka; Kunihiko Kaneko

    2014-03-15

    Cells generally convert external nutrient resources to support metabolismand growth. Understanding the thermodynamic efficiency of this conversion is essential to determine the general characteristics of cellular growth. Using a simple protocell model with catalytic reaction dynamics to synthesize the necessary enzyme and membrane components from nutrients, the entropy production per unit cell-volume growth is calculated analytically and numerically based on the rate equation for chemical kinetics and linear non-equilibrium thermodynamics. The minimal entropy production per unit cell growth is found to be achieved at a non-zero nutrient uptake rate, rather than at a quasi-static limit as in the standard Carnot engine. This difference appears because the equilibration mediated by the enzyme exists only within cells that grow through enzyme and membrane synthesis. Optimal nutrient uptake is also confirmed by protocell models with many chemical components synthesized through a catalytic reaction network. The possible relevance of the identified optimal uptake to optimal yield for cellular growth is also discussed.

  12. Birth weight and academic achievement in childhood.

    PubMed

    Chatterji, Pinka; Kim, Dohyung; Lahiri, Kajal

    2014-09-01

    Research has shown that birth weight has a lasting impact on later-life outcomes such as educational attainment and earnings. This paper examines the role of health at birth in determining academic achievement in childhood, which may provide the link between birth weight and adult outcomes. Using three waves of the Child Development Supplement of the Panel Study of Income Dynamics data over 1997-2007, we build on the literature by employing the fetal growth rate as a proxy for net nutritional intake in utero and propose a nested error-component two-stage least squares estimator that draws on internal instruments from alternative dimensions of the multilevel panel data set. In particular, this alternative estimator allows us to exploit the information on children with no siblings in the sample, which comprise over 40% of the observations in our sample, as well as to obtain coefficient estimates for the time-invariant variables such as race and maternal education. This would not be feasible with the usual mother fixed effects estimation. We obtain modest but significant effects of both birth weight and the fetal growth rate on math and reading scores, with the effects concentrated in the low birth weight range. Infant health measures appear to explain little of the well-documented racial disparity in test scores. PMID:25044537

  13. Optimization research for ash dam cross section

    Microsoft Academic Search

    Shouyi Li; Jihua Zhao; Yaolong Chen; Jusheng Yang

    2005-01-01

    This paper presents a new approach for the optimization analysis of ash dam slope stability calculation by using lattice method. A further study for the optimization design of ash dam cross section using exhaustion method is also provided. The numerical result analysis indicates that using combined optimization method of lattice and exhaustion to design ash dam cross section can achieve

  14. Optimal refrigerator

    E-print Network

    Armen E. Allahverdyan; Karen Hovhannisyan; Guenter Mahler

    2010-07-25

    We study a refrigerator model which consists of two $n$-level systems interacting via a pulsed external field. Each system couples to its own thermal bath at temperatures $T_h$ and $T_c$, respectively ($\\theta\\equiv T_c/T_hrefrigerator functions in two steps: thermally isolated interaction between the systems driven by the external field and isothermal relaxation back to equilibrium. There is a complementarity between the power of heat transfer from the cold bath and the efficiency: the latter nullifies when the former is maximized and {\\it vice versa}. A reasonable compromise is achieved by optimizing the product of the heat-power and efficiency over the Hamiltonian of the two system. The efficiency is then found to be bounded from below by $\\zeta_{\\rm CA}=\\frac{1}{\\sqrt{1-\\theta}}-1$ (an analogue of the Curzon-Ahlborn efficiency), besides being bound from above by the Carnot efficiency $\\zeta_{\\rm C} = \\frac{1}{1-\\theta}-1$. The lower bound is reached in the equilibrium limit $\\theta\\to 1$. The Carnot bound is reached (for a finite power and a finite amount of heat transferred per cycle) for $\\ln n\\gg 1$. If the above maximization is constrained by assuming homogeneous energy spectra for both systems, the efficiency is bounded from above by $\\zeta_{\\rm CA}$ and converges to it for $n\\gg 1$.

  15. Mathematics anxiety and mathematics achievement

    Microsoft Academic Search

    Brian F. Sherman

    2003-01-01

    This paper is a distillation of the major result from the 1998 Ph.D. thesis of the late David Wither. It details a longitudinal\\u000a study over five years of the relationship between mathematics anxiety and mathematics achievement. It starts from the already\\u000a well documented negative correlation between the two, and seeks to establish one of the three hypotheses—that mathematics\\u000a anxiety causes

  16. Mathematics, Engineering, Science Achievement (MESA)

    NSDL National Science Digital Library

    California's Mathematics, Engineering, Science Achievement (MESA), founded in 1970, assists students to become highly trained technological professionals by serving educationally disadvantaged students and, to the extent possible by law, emphasizes participation by students from groups with low eligibility rates for four-year colleges. Learn about MESA initiatives such as its Schools Program (MSP), Success Through Collaboration (MESA STC), California Community College Program (CCCP), and Engineering Program (MEP).

  17. The Effects of Chronic Achievement Motivation and Achievement Primes on the Activation of Achievement and Fun Goals

    Microsoft Academic Search

    William Hart; Dolores Albarracín

    2009-01-01

    This research examined the hypothesis that situational achievement cues can elicit achievement or fun goals depending on chronic differences in achievement motivation. In 4 studies, chronic differences in achievement motivation were measured, and achievement-denoting words were used to influence behavior. The effects of these variables were assessed on self-report inventories, task performance, task resumption following an interruption, and the pursuit

  18. Soaking of DNA into crystals of archaeal RNA polymerase achieved by desalting in droplets.

    PubMed

    Wojtas, Magdalena N; Abrescia, Nicola G A

    2012-09-01

    Transcription is a fundamental process across the three domains of life and is carried out by multi-subunit enzymatic DNA-directed RNA polymerases (RNAPs). The interaction of RNAP with nucleic acids is tightly controlled for precise and processive RNA synthesis. Whilst a wealth of structural information has been gathered on the eukaryotic Pol II in complex with DNA/RNA, no information exists on its ancestral counterpart archaeal RNAP. Thus, in order to extend knowledge of the archaeal transcriptional apparatus, crystallization of Sulfolobus shibatae RNAP (molecular mass of ~400 kDa) with DNA fragments was pursued. To achieve this goal, crystal growth was first optimized using a nanoseeding technique. An ad hoc soaking protocol was then put into place, which consisted of gently exchanging the high-salt buffer used for apo-RNAP crystal growth into a low-salt buffer necessary for DNA binding to RNAP. Of the various crystals screened, one diffracted to 4.3 Å resolution and structural analysis showed the presence of bound DNA [Wojtas et al. (2012). Nucleic Acids Res. 40, doi:10.1093/nar/gks692]. PMID:22949213

  19. Growth in thyrotoxicosis

    Microsoft Academic Search

    J M Buckler; H Willgerodt; E Keller

    1986-01-01

    To study the effect of thyrotoxicosis on growth, 46 children and adolescents presenting with thyrotoxicosis have been reviewed and followed up for several years, in most cases until adult height was achieved. At presentation the children were underweight for height but were above expected heights even if already well advanced in puberty. Despite bone ages often being very advanced at

  20. The Seeds of Growth.

    ERIC Educational Resources Information Center

    Hanushek, Eric A.

    2002-01-01

    Argues that human capital formation is the key to economic growth, that U.S. students are falling behind the rest of the World in math and science achievement because of the decline in the quality of their schooling, and that without better schools, other factors such as a quality higher education system may not sustain future U.S. economic…

  1. The Effects of Temperature and Nutritional Conditions on Mycelium Growth of Two Oyster Mushrooms (Pleurotus ostreatus and Pleurotus cystidiosus)

    PubMed Central

    Hoa, Ha Thi

    2015-01-01

    The influences of temperature and nutritional conditions on the mycelium growth of oyster mushroom Pleurotus ostreatus (PO) and Pleurotus cystidiosus (PC) were investigated in laboratory experiment during the summer season of 2014. The results of the experiment indicated that potato dextrose agar (PDA) and yam dextrose agar (YDA) were the most suitable media for the mycelium growth of oyster mushroom PO while four media (PDA, YDA, sweet potato dextrose agar, and malt extract agar medium) were not significantly different in supporting mycelium growth of oyster mushroom PC. The optimal temperature for mycelium growth of both oyster mushroom species was obtained at 28?. Mycelium growth of oyster mushroom PO was improved by carbon sources such as glucose, molasses, and at 1~5% sucrose concentration, mycelium colony diameter of mushroom PO was achieved the highest value. Whereas glucose, dextrose, and sucrose as carbon sources gave the good mycelium growth of oyster mushroom PC, and at 1~3% sucrose concentration, mycelium colony diameter of PC was achieved the maximum value. Ammonium chloride concentrations at 0.03~0.09% and 0.03~0.05% also gave the greatest values in mycelium colony diameter of mushroom PO and PC. Brown rice was found to be the most favourable for mycelium growth of two oyster mushroom species. In addition, sugarcane residue, acasia sawdust and corn cob were selected as favourable lignocellulosic substrate sources for mycelium growth of both oyster mushrooms.

  2. Growth Disorders

    MedlinePLUS

    ... because their parents are. But some children have growth disorders. Growth disorders are problems that prevent children from developing ... or other features. Very slow or very fast growth can sometimes signal a gland problem or disease. ...

  3. Growth and characterization of group iiinitrides by migration-enhanced afterglow epitaxy

    NASA Astrophysics Data System (ADS)

    Gergova, Rositsa

    The work presented in this thesis investigates the growth and properties of group III- nitride semiconductors that were grown using the Migration Enhanced Afterglow Epitaxy (MEAglow) method. This work was to enhance the understanding of the MEAglow growth process towards the improvement of quality of the layers grown using this technique. The MEAglow technique applies the migration enhanced epitaxy method in a low pressure plasma-based CVD reactor, which has a potential of producing high quality epitaxial group III-nitride layers at relatively low growth temperatures on large deposition areas. The low temperature pulse growth in metal-rich regime, comprising the MME method was employed under growth pressures between 500 mTorr and 3000 mTorr. As the MME method up to this point has been used only for MBE systems, study of the impact of the growth pressure on the materials properties was necessary. In this work the pressure dependence was mapped to an existing surface phase diagram for MBE systems by calculating the number of nitrogen gas phase collisions and the metalorganic bombardment rate, for the specific to the prototype reactor parameters, to a first approximation. This was done in order to achieve an intermediate regime free of metal droplets for growth in metal-rich regime. High quality epitaxial InN layers were accomplished on extremely thin and smooth Ga2O3 buffer layers. These results indicate a potential for the application of Ga2O3 buffers in InN growth. The MEAglow InN layers were further optimized for growth on commercially available GaN buffer layers and excellent two-dimensional growth was achieved for layers grown under metal-rich conditions at 512 °C. Post-growth annealing studies were carried out for InN layers grown at temperatures below 400 °C to study the limiting processes of the removal of excess nitrogen, believed to be a dominant defect in InN films grown in plasma-based systems at very low temperatures. Variations in GaN stoichiometry under certain growth conditions and the effect of similar growth conditions on MEAglow grown InGaN were also examined. The growth of MEAglow InGaN samples on sapphire substrates was optimized to reduce the indium surface segregation and phase separation of the material.

  4. Dynamic Optimization

    NASA Technical Reports Server (NTRS)

    Laird, Philip

    1992-01-01

    We distinguish static and dynamic optimization of programs: whereas static optimization modifies a program before runtime and is based only on its syntactical structure, dynamic optimization is based on the statistical properties of the input source and examples of program execution. Explanation-based generalization is a commonly used dynamic optimization method, but its effectiveness as a speedup-learning method is limited, in part because it fails to separate the learning process from the program transformation process. This paper describes a dynamic optimization technique called a learn-optimize cycle that first uses a learning element to uncover predictable patterns in the program execution and then uses an optimization algorithm to map these patterns into beneficial transformations. The technique has been used successfully for dynamic optimization of pure Prolog.

  5. Achieving true sustainability of zoo populations.

    PubMed

    Lacy, Robert C

    2013-01-01

    For the last 30 years, cooperative management of irreplaceable animal populations in zoos and aquariums has focused primarily on the goal of minimizing genetic decay within defined time frames, and large advances have been made in technologies to optimize genetic management of closed populations. However, recent analyses have shown that most zoo programs are not projected to meet their stated goals. This has been described as a lack of achieving "sustainability" of the populations, yet by definition a goal of managed decay is not a plan for sustainability. True sustainability requires management of the resource in manner that does not deplete its value for the future. Achieving such sustainability for many managed populations may require changing from managing isolated populations to managing populations that are part of a broader metapopulation, with carefully considered exchange between populations across a spectrum of ex situ to in situ. Managing zoo populations as components of comprehensive conservation strategies for the species will require research on determinants of various kinds of genetic, physiological, behavioral, and morphological variation and their roles in population viability, development of an array of management techniques and tools, training of population managers in metapopulation management and integrated conservation planning, and projections of impacts of management strategies on the viability of the captive populations and all populations that are interactively managed or affected. Such a shift in goals and methods would result in zoo population management being an ongoing part of species conservation rather than short-term or isolated from species conservation. Zoo Biol. 32:19-26, 2013. © 2012 Wiley Periodicals, Inc. PMID:22753040

  6. Site-specific growth of polymers on silica rods.

    PubMed

    Peng, Bo; Soligno, Giuseppe; Kamp, Marlous; de Nijs, Bart; de Graaf, Joost; Dijkstra, Marjolein; van Roij, René; van Blaaderen, Alfons; Imhof, Arnout

    2014-12-28

    Colloids specifically developed for self-assembly (SA) into advanced functional materials have rapidly become more complex, as this complexity allows for more ways to optimize both the SA process and the properties of the resulting materials. For instance, by creating 'patchy' particles more open structures can be achieved through directional interactions. However, the number of ways in which site-specific chemistry can be achieved on particle surfaces is still limited. Here, we show how polymer patches can be specifically grown onto only the flat end of bullet-shaped silica rods by utilizing a subtle anisotropy in surface tension and shape caused by the growth mechanism of the rods. Conversely, if the bullet-shaped silica rods are used as 'Pickering-emulsion' stabilizers the same surface tension effects exclusively direct the orientation of the rods into a 'hedgehog-morphology'. Finally, we demonstrate how an external electric field can direct the particles in a 'vectorial' way. PMID:25356961

  7. Achieving permanency for LGBTQ youth.

    PubMed

    Jacobs, Jill; Freundlich, Madelyn

    2006-01-01

    This article brings together two significant efforts in the child welfare field: achieving permanence for youth in out-of-home care and meeting the needs of lesbian, gay, bisexual, transgender and questioning (LGBTQ) youth. During the past several years, a national movement has taken place to assure all children and youth have a permanent family connection before leaving the child welfare system; however, LGBTQ youth are not routinely included in the permanency discussions. At the same time, efforts in addressing the needs of LGBTQ youth have increased, but permanency is rarely mentioned as a need. This article offers models of permanence and practices to facilitate permanence with LGBTQ youth and their families. It also offers a youth-driven, individualized process, using youth development principles to achieve relational, physical, and legal permanence. Reunification efforts are discussed, including services, supports, and education required for youth to return to their family of origin. For those who cannot return home, other family resources are explored. The article also discusses cultural issues as they affect permanence for LGBTQ youth, and, finally, addresses the need for ongoing support services to sustain and support permanency. PMID:16846117

  8. Achieving MAC layer fairness in wireless packet networks

    Microsoft Academic Search

    Thyagarajan Nandagopal; Tae-Eun Kim; Xia Gao; Vaduvur Bharghavan

    2000-01-01

    Link-layer fairness models that have been proposed for wireline and packet cellular networks cannot be generalized for shared channel wireless networks because of the unique characteristics of the wireless channel, such as location-dependent contention, inherent conflict between optimizing channel utilization and achieving fairness, and the absence of any centralized control.In this paper, we propose a general analytical framework that captures

  9. Growth and study of nonlinear optical materials for frequency conversion devices with applications in defence and security

    NASA Astrophysics Data System (ADS)

    Tassev, V.; Snure, M.; Vangala, S.; Kimani, M.; Peterson, R.; Schunemann, P.

    2014-10-01

    A series of nonlinear materials including GaAs, GaP, and ZnSe have been examined to determine their suitability for non-linear frequency conversion devices (FCD) and more specifically their use as high power, compact and broadly tunable IR and THz sources for defense and security applications. The more mature GaAs was investigated to reveal the causes for the optical losses that restrict achievement of higher conversion efficiency in quasi-phasematched FCD, while the efforts with GaP were oriented in developing simple, cost effective techniques for fabrication of orientation patterned (OP) templates and optimizing the subsequent thick HVPE growth on these templates. Thus, average growth rates of 50- 70 ?m/h were achieved in up to 8-hour long experiments. High optical layer quality was achieved by suitable control of the process parameters. The optimal orientation of the pattern was determined and used as essential feedback aiming to improve the template preparation. This led to the production of the first 300-400 ?m thick device quality OPGaP. Efforts to suppress the parasitic nucleation during growths with longer duration or to achieve thicker layers by a 2 step growth process were also made. The main challenge with the newer candidate, OPZnSe, was to establish suitable regimes for hydrothermal growth on plain (001) ZnSe seeds grown by chemical vapor deposition. Two different temperature ranges, 330-350 °C and 290-330 °C, were investigated. The mineralized concentration was also manipulated to accelerate the growth in (111) direction and, thus, to improve the growth in (001) direction. The next material in the line is GaN. The traditional HVPE approach will be combined with a growth at low reactor pressure. Growths will be performed in the next sequence: growth on thin GaN layers grown by MOCVD on sapphire wafers, growth on half-patterned GaN templates with different orientations and, finally, growth on OPGaN templates.

  10. Integrated multidisciplinary design optimization of rotorcraft

    NASA Technical Reports Server (NTRS)

    Adelman, Howard M.; Mantay, Wayne R.

    1989-01-01

    The NASA/Army research plan for developing the logic elements for helicopter rotor design optimization by integrating appropriate disciplines and accounting for important interactions among the disciplines is discussed. The paper describes the optimization formulation in terms of the objective function, design variables, and constraints. The analysis aspects are discussed, and an initial effort at defining the interdisciplinary coupling is summarized. Results are presented on the achievements made in the rotor aerodynamic performance optimization for minimum hover horsepower, rotor dynamic optimization for vibration reduction, rotor structural optimization for minimum weight, and integrated aerodynamic load/dynamics optimization for minimum vibration and weight.

  11. Role of prism decussation on fatigue crack growth and fracture of human enamel.

    PubMed

    Bajaj, Devendra; Arola, Dwayne

    2009-10-01

    The role of prism decussation on the crack growth resistance of human enamel is evaluated. Miniature inset compact tension (CT) specimens embodying a section of cuspal enamel were subjected to Mode I cyclic or monotonic loads. Cracks were grown in either the forward (from outer enamel inwards) or reverse (from inner enamel outwards) direction and the responses were compared quantitatively. Results showed that the outer enamel exhibits lower resistance to the inception and growth of cracks. Regardless of the growth direction, the near-threshold region of cyclic extension was typical of "short crack" behavior (i.e. deceleration of growth with an increase in crack length). Cyclic crack growth was more stable in the forward direction and occurred over twice the spatial distance achieved in the reverse direction. In response to the monotonic loads, a rising R-curve response was exhibited by growth in the forward direction only. The total energy absorbed in fracture for the forward direction was more than three times that in the reverse. The rise in crack growth resistance was largely attributed to a combination of mechanisms that included crack bridging, crack bifurcation and crack curving, which were induced by decussation in the inner enamel. An analysis of the responses distinguished that the microstructure of enamel appears optimized for resisting crack growth initiating from damage at the tooth's surface. PMID:19433137

  12. Metaheuristics in Combinatorial Optimization

    Microsoft Academic Search

    Michel Gendreau; Jean-yves Potvin

    2005-01-01

    The emergence of metaheuristics for solving difficult combinatorial optimization problems is one of the most notable achievements\\u000a of the last two decades in operations research. This paper provides an account of the most recent developments in the field\\u000a and identifies some common issues and trends. Examples of applications are also reported for vehicle routing and scheduling\\u000a problems.

  13. Optimal Centroid Position Estimation

    SciTech Connect

    Candy, J V; McClay, W A; Awwal, A S; Ferguson, S W

    2004-07-23

    The alignment of high energy laser beams for potential fusion experiments demand high precision and accuracy by the underlying positioning algorithms. This paper discusses the feasibility of employing online optimal position estimators in the form of model-based processors to achieve the desired results. Here we discuss the modeling, development, implementation and processing of model-based processors applied to both simulated and actual beam line data.

  14. Achieving Quality in Occupational Health

    NASA Technical Reports Server (NTRS)

    O'Donnell, Michele (Editor); Hoffler, G. Wyckliffe (Editor)

    1997-01-01

    The conference convened approximately 100 registered participants of invited guest speakers, NASA presenters, and a broad spectrum of the Occupational Health disciplines representing NASA Headquarters and all NASA Field Centers. Centered on the theme, "Achieving Quality in Occupational Health," conferees heard presentations from award winning occupational health program professionals within the Agency and from private industry; updates on ISO 9000 status, quality assurance, and information technologies; workshops on ergonomics and respiratory protection; an overview from the newly commissioned NASA Occupational Health Assessment Team; and a keynote speech on improving women's health. In addition, NASA occupational health specialists presented 24 poster sessions and oral deliveries on various aspects of current practice at their field centers.

  15. Adaptive Growth Decisions in Butterflies

    NSDL National Science Digital Library

    Karl Gotthard (Stockholm University; )

    2008-03-01

    Caterpillars have a great capacity for rapid weight gain, but to reap the benefits of this capacity, larvae must be able to survive in a hostile environment and emerge as adults at the right time of year. In this article, I review examples of growth decisions in butterfly larvae that can be viewed as adaptations for optimized growth performance. These include sex-specific growth decisions that lead to protandry and sexual size dimorphism, fine-tuning of growth in response to photoperiod and temperature, development of alternative larval morphs that mimic the plant structures they feed on, and the peculiar growth patterns of lycenid butterflies that manipulate ants and grow as cuckoos inside ant nests. I conclude that growth of an individual can be seen as the sum of several environmentally dependent decisions, which may influence the growth trajectory by changes in physiology, behavior, and morphology.

  16. Transglutaminases: recent achievements and new sources.

    PubMed

    Martins, Ivone M; Matos, Mauro; Costa, Rodrigo; Silva, Fátima; Pascoal, Ananias; Estevinho, Letícia M; Choupina, Altino Branco

    2014-08-01

    Transglutaminases are a family of enzymes (EC 2.3.2.13), widely distributed in various organs, tissues, and body fluids, that catalyze the formation of a covalent bond between a free amine group and the ?-carboxamide group of protein or peptide-bound glutamine. Besides forming these bonds, that exhibit high resistance to proteolytic degradation, transglutaminases also form extensively cross-linked, generally insoluble, protein biopolymers that are indispensable for the organism to create barriers and stable structures. The extremely high cost of transglutaminase of animal origin has hampered its wider application and has initiated efforts to find an enzyme of microbial origin. Since the early 1990s, many microbial transglutaminase-producing strains have been found, and production processes have been optimized. This has resulted in a rapidly increasing number of applications of transglutaminase in the food sector. However, applications of microbial transglutaminase in other sectors have also been explored, but in a much lesser extent. Our group has identified a transglutaminase in the oomycete Phytophthora cinnamomi, which is able to induct defense responses and disease-like symptoms. In this mini-review, we report the achievements in this area in order to illustrate the importance and the versatility of transglutaminases. PMID:24962119

  17. Isoflavone Augmentation in Soybean Cell Cultures Is Optimized Using Response Surface Methodology.

    PubMed

    Akitha Devi, M K; Giridhar, P

    2014-03-31

    Glycine max contains potential therapeutic isoflavones, and its productivity in plants is considerably influenced worldwide by several biotic and abiotic factors. Optimization of soybean cell suspension cultures (Indian variety, JS 335) to maximize the cell growth and isoflavone production in the present study was performed using response surface methodology (RSM) with three independent variables of plant growth regulators, 2,4-dichlorophenoxyacetic acid (2,4-D), 1-naphthalene acetic acid (?-NAA), and kinetin (Kn). The maximum biomass achieved was 70.62 g/L dry weight (dw) using the optimized medium of 2.10 mg/L 2,4-D, 5.52 mg/L ?-NAA, and 0.35 mg/L Kn supplemented in the Murashige and Skoog (MS) basal medium. The total isoflavone content of 38.59 mg/g of dw was obtained in the medium with optimized conditions of 1.33 mg/L 2,4-D, 1.76 mg/L ?-NAA, and 0.15 mg/L Kn. In comparison to field-grown soybean seeds, the cell suspension cultures profoundly augmented isoflavone concentrations. The optimized conditions for both biomass and total isoflavone content were evaluated by superimposing the contour plots. The results suggested that the optimized medium of cell suspension cultures possibly be used for scale-up studies in bioreactors to offer a high content of bioactive isoflavones. PMID:24678665

  18. Designing Sensor Networks by a Generalized Highly Optimized Tolerance Model

    NASA Astrophysics Data System (ADS)

    Miyano, Takaya; Yamakoshi, Miyuki; Higashino, Sadanori; Tsutsui, Takako

    A variant of the highly optimized tolerance model is applied to a toy problem of bioterrorism to determine the optimal arrangement of hypothetical bio-sensors to avert epidemic outbreak. Nonlinear loss function is utilized in searching the optimal structure of the sensor network. The proposed method successfully averts disastrously large events, which can not be achieved by the original highly optimized tolerance model.

  19. Process analysis and optimization of biodiesel production from vegetable oils

    E-print Network

    Myint, Lay L.

    2009-05-15

    , to identify related key design criteria, and optimize performance. The overall goal of this work was to design and optimize biodiesel (Fatty Acid Methyl Ester “FAME”) production from vegetable oil. To achieve this goal, several interconnected research...

  20. Smart Growth

    NSDL National Science Digital Library

    2001-01-01

    This site features resources focused on "smart growth," growth that attempts to "minimize environmental and health impacts while promoting economic prosperity." The site explains smart growth; provides links to funding sources, resources, and members of the smart growth network, a coalition of government, business, and civic organizations; collects related fact sheets, reports, grant products, and articles; and summarizes some smart growth projects. Policy makers and environmentalists will want to visit this site.

  1. A Unified Approach to QoS-Guaranteed Scheduling for Channel-Adaptive Wireless Networks Terminals wirelessly-linked to an access point should be able to achieve near-optimal data rates, while maintaining required quality of service, by using simple scheduling algorithms

    Microsoft Academic Search

    Xin Wang; Georgios B. Giannakis; Antonio G. Marques

    Scheduling amounts to allocating optimally channel, rate and power resources to multiple connections with diverse quality-of-service (QoS) requirements. It consti- tutes a throughput-critical task at the medium access control layer of today's wireless networks that has been tackled by seemingly unrelated information-theoretic and protocol design approaches. Capitalizing on convex optimization and stochastic approximation tools, the present paper develops a unified

  2. Surfactants in epitaxial growth

    NASA Astrophysics Data System (ADS)

    Copel, M.; Reuter, M. C.; Kaxiras, Efthimios; Tromp, R. M.

    1989-08-01

    The role of surface-active species (surfactants) in heteroepitaxial crystal growth has been investigated. In general, the growth mode is determined by the balance between surface, interface, and film free energies. Thus, if A wets B, B will not wet A. Any attempt at growing an A/B/A heterostructure must overcome this fundamental obstacle. The use of a segregating surfactant is proposed to reduce the surface free energies of A and B and suppress island formation, as demonstrated in the growth of Si/Ge/Si(001) with a monolayer of As. Control of growth by manipulation of surface energetics provides a new avenue to achieve high-quality man-made microstructures against thermodynamic odds.

  3. Achieving the Benefits of Safeguards by Design

    SciTech Connect

    Trond Bjornard; Robert Bean; David Hebditch; Jim Morgan; Bruce Meppen; Scott DeMuth; Michael Ehinger; John Hockert

    2008-07-01

    The overarching driver for developing a formalized process to achieve safeguards by design is to support the global growth of nuclear power while reducing ‘nuclear security’ risks. This paper discusses an institutional approach to the design process for a nuclear facility, for designing proliferation resistance, international safeguards and U.S. national safeguards and security into new nuclear facilities. In the United States, the need exists to develop a simple, concise, formalized, and integrated approach for incorporating international safeguards and other non-proliferation considerations into the facility design process. An effective and efficient design process is one which clearly defines the functional requirements at the beginning of the project and provides for the execution of the project to achieve a reasonable balance among competing objectives in a cost effective manner. Safeguards by Design is defined as “the integration of international and national safeguards, physical security and non-proliferation features as full and equal partners in the design process of a nuclear energy system or facility,” with the objective to achieve facilities that are intrinsically more robust while being less expensive to safeguard and protect. This Safeguards by Design process has been developed such that it: • Provides improved safeguards, security, and stronger proliferation barriers, while reducing the life cycle costs to the operator and regulatory agencies, • Can be translated to any international context as a model for nuclear facility design, • Fosters a culture change to ensure the treatment of ‘nuclear security’ considerations as “full and equal” partners in the design process, • Provides a useful tool for the project manager responsible for the design, construction, and start-up of nuclear facilities, and • Addresses the key integration activities necessary to efficiently incorporate International Atomic Energy Agency safeguards into the design of nuclear facilities. This paper describes the work that has been completed in the development of a Safeguards by Design process for a project, illustrated by flow diagrams based upon the project phases described in U.S. Department of Energy Order 413.3A, Program and Project Management for the Acquisition of Capital Assets. The institutionalization of the Safeguards by Design process directly supports the goals of the Next Generation Safeguards Initiative and also aligns with goals and objectives of the International Atomic Energy Agency. Other benefits from institutionalizing this Safeguards by Design process are discussed within this paper.

  4. ExxonMobil Baton Rouge Chemicals: Energy Optimization in a Turndown Environment

    E-print Network

    Geier, E.; Panaev, L.; Waite, R.; Eiklor, L.

    -line control and optimization every minute ? Benefit of DMC on butadiene unit ? Process optimization ? Maximization of heat recovery ? Other production optimizations achieved ? Console operator tool ? Quicker reaction time to changing parameters...

  5. Reading Achievement Trajectories for Students With Learning Disabilities During the Elementary School Years

    Microsoft Academic Search

    Sharon Judge; Sherry Mee Bell

    2010-01-01

    Using hierarchical linear modeling and longitudinal data from the first 6 waves of the Early Childhood Longitudinal Study–Kindergarten cohort, the authors examined reading achievement and growth rates by learning disability (LD) subgroup. The 2-level (time–student) growth curve model indicated that lower levels of reading achievement were already evident at kindergarten entry for all subgroups of students identified during the elementary

  6. Closing the Achievement Gap: Challenges and Opportunities

    ERIC Educational Resources Information Center

    Robards, Shirley N.

    2008-01-01

    Closing the achievement gap between low- and high-achieving public school students is an important goal of public education. This article explores background information and research and discusses examples of best practices to close the achievement gap. Several plans have been proposed as ways to enhance the achievement of under-represented…

  7. Optimal Implementation of Intervention Strategies for Elderly People with Ludomania

    PubMed Central

    Kim, Byul Nim; Masud, M.A.; Kim, Yongkuk

    2014-01-01

    Objectives Now-a-days gambling is growing especially fast among older adults. To control the gratuitous growth of gambling, well-analyzed scientific strategies are necessary. We tried to analyze the adequacy of the health of society mathematically through immediate treatment of patients with early prevention. Methods The model from Lee and Do was modified and control parameters were introduced. Pontryagin's Maximum Principle was used to obtain an optimal control strategy. Results Optimal control can be achieved through simultaneous use of the control parameters, though it varies from society to society. The control corresponding to prevention needed to be implemented in full almost all the time for all types of societies. In the case of the other two controls, the scenario was greatly affected depending on the types of societies. Conclusion Prevention and treatment for elderly people with ludomania are the main intervention strategies. We found that optimal timely implementation of the intervention strategies was more effective. The optimal control strategy varied with the initial number of gamblers. However, three intervention strategies were considered, among which, preventing people from engaging in all types of gambling proved to be the most crucial. PMID:25389512

  8. Methods to optimize selective hyperthermia

    NASA Astrophysics Data System (ADS)

    Cowan, Thomas M.; Bailey, Christopher A.; Liu, Hong; Chen, Wei R.

    2003-07-01

    Laser immunotherapy, a novel therapy for breast cancer, utilizes selective photothermal interaction to raise the temperature of tumor tissue above the cell damage threshold. Photothermal interaction is achieved with intratumoral injection of a laser absorbing dye followed by non-invasive laser irradiation. When tumor heating is used in combination with immunoadjuvant to stimulate an immune response, anti-tumor immunity can be achieved. In our study, gelatin phantom simulations were used to optimize therapy parameters such as laser power, laser beam radius, and dye concentration to achieve maximum heating of target tissue with the minimum heating of non-targeted tissue. An 805-nm diode laser and indocyanine green (ICG) were used to achieve selective photothermal interactions in a gelatin phantom. Spherical gelatin phantoms containing ICG were used to simulate the absorption-enhanced target tumors, which were embedded inside gelatin without ICG to simulate surrounding non-targeted tissue. Different laser powers and dye concentrations were used to treat the gelatin phantoms. The temperature distributions in the phantoms were measured, and the data were used to determine the optimal parameters used in selective hyperthermia (laser power and dye concentration for this case). The method involves an optimization coefficient, which is proportional to the difference between temperatures measured in targeted and non-targeted gel. The coefficient is also normalized by the difference between the most heated region of the target gel and the least heated region. A positive optimization coefficient signifies a greater temperature increase in targeted gelatin when compared to non-targeted gelatin, and therefore, greater selectivity. Comparisons were made between the optimization coefficients for varying laser powers in order to demonstrate the effectinvess of this method in finding an optimal parameter set. Our experimental results support the proposed use of an optimization coefficient to find optimal parameters for selective hyperthermia.

  9. Optimization approach to entanglement distillation

    E-print Network

    T. Opatrny; G. Kurizki

    1999-04-09

    We put forward a method for optimized distillation of partly entangled pairs of qubits into a smaller number of more entangled pairs by recurrent local unitary operations and projections. Optimized distillation is achieved by minimization of a cost function with up to 30 real parameters, which is chosen to be sensitive to the fidelity and the projection probability at each step. We show that in many cases this approach can significantly improve the distillation efficiency in comparison to the present methods.

  10. CIAS: achieving interoperability using CORBA

    NASA Astrophysics Data System (ADS)

    Moreno, Ramon A.; Fiales, Vivian R.; Furuie, Sergio S.

    2002-05-01

    This paper presents one of the efforts of the Heart Institute of Sao Paulo for the development of a distributed system for retrieving and research of medical images and medical information. The objective is the implementation of an open architecture based on the Clinical Image Access Service (CIAS) specification, defined by Object Management Group, which allows the recover of meta-data and relevant information for general practitioners and clinical specialists in a multi-platform, distributed environment. The CIAS-InCor was developed in Java language, to achieve multi-platform capability, together with CORBA. The images are received in DICOM format, being stored into relational database for the recover of meta-information through the CIAS specification. A prototype of a CIAS server and client were designed and implemented. It has been possible to recover images and clinical information from the CIAS server in a distributed, non-homogenous environment with success. Through the use of standards and new technologies the Heart Institute of Sao Paulo is reaching a high level of integration between systems and equipments and going towards the development of a complete electronic medical record. The CIAS is still an unfinished specification with good points like interoperability and weaknesses like the lack of semantics between exchanged data.

  11. Achieving a polio free world

    PubMed Central

    2014-01-01

    Recently, the World Health Organization (WHO) declared that the spread of polio is an international public health emergency, and a coordinated international response is sought. Although the importance of such a response is recognized, there are challenges to stopping the spread of polio and achieving a polio free world. The most important issue is directing limited national resources to the specific areas where polio is endemic. In an article published in BMC Medicine, Upfill-Brown and his colleagues recognized this problem and successfully identified the potential risk areas in Nigeria using a validated spatial predictive model of wild poliovirus circulation. They also showed that a lower vaccine-derived population immunity is associated with the probability of a higher number of wild poliovirus cases within a district. Identification of the potential risk areas and understanding the magnitude of risk may help direct limited resources of the endemic countries to areas most at risk to maximize the impact of interventions and motivate the people to participate in the intervention program. These efforts are crucial if these endemic countries hope to eradicate polio. Please see related research article: http://www.biomedcentral.com/1741-7015/12/92.

  12. Academic Achievement Among Juvenile Detainees.

    PubMed

    Grigorenko, Elena L; Macomber, Donna; Hart, Lesley; Naples, Adam; Chapman, John; Geib, Catherine F; Chart, Hilary; Tan, Mei; Wolhendler, Baruch; Wagner, Richard

    2013-09-24

    The literature has long pointed to heightened frequencies of learning disabilities (LD) within the population of law offenders; however, a systematic appraisal of these observations, careful estimation of these frequencies, and investigation of their correlates and causes have been lacking. Here we present data collected from all youth (1,337 unique admissions, mean age 14.81, 20.3% females) placed in detention in Connecticut (January 1, 2010-July 1, 2011). All youth completed a computerized educational screener designed to test a range of performance in reading (word and text levels) and mathematics. A subsample (n = 410) received the Wide Range Achievement Test, in addition to the educational screener. Quantitative (scale-based) and qualitative (grade-equivalence-based) indicators were then analyzed for both assessments. Results established the range of LD in this sample from 13% to 40%, averaging 24.9%. This work provides a systematic exploration of the type and severity of word and text reading and mathematics skill deficiencies among juvenile detainees and builds the foundation for subsequent efforts that may link these deficiencies to both more formal, structured, and variable definitions and classifications of LD, and to other types of disabilities (e.g., intellectual disability) and developmental disorders (e.g., ADHD) that need to be conducted in future research. PMID:24064502

  13. Enhanced thermal conductivity of polycrystalline aluminum nitride thin films by optimizing the interface structure

    SciTech Connect

    Pan, T. S.; Zhang, Y.; Huang, J.; Zeng, B.; Hong, D. H.; Zeng, H. Z.; Gao, M.; Huang, W.; Lin, Y. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wang, S. L. [Analytical and Testing Center, Sichuan University, Chengdu 610065 (China)

    2012-08-15

    The growth-temperature dependency and interface structure effects on the thermal conductivity of the highly textured AlN thin films on (001) Si substrates were systematically studied by characterizing the crystal structures, surface morphologies, interface structures, chemical compositions, and thermal conductivity using x-ray diffraction analysis, atomic force microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and 3-omega method, respectively. By optimizing the interface microstructure and the growth temperature, thermal conductivity of polycrystalline AlN thin films can be greatly enhanced from 9.9 to 26.7 W/mK, when the growth temperature increases from 330 to 560 Degree-Sign C. This achievement is considered to be associated with the diminishment of the amorphous and disordered layer at the AlN/Si interface.

  14. Examination of growth rate during hydride vapor phase epitaxy of GaN on ammonothermal GaN seeds

    NASA Astrophysics Data System (ADS)

    Sochacki, T.; Amilusik, M.; Fijalkowski, M.; Lucznik, B.; Weyher, J. L.; Grzegory, I.; Kucharski, R.; Iwinska, M.; Bockowski, M.

    2014-12-01

    One of the main advantages of the hydride vapor phase epitaxy (HVPE) method for crystallizing bulk gallium nitride is the crystallization of GaN with a relatively high growth rate (>100 ?m/h). In this paper various growth rates in the c-direction during crystallization of GaN by HVPE on ammonothermally grown GaN crystals are determined and examined. The influence of the highest (380 ?m/h) and the lowest (40 ?m/h) growth rate on the structural quality and purity of the HVPE-GaN crystals is analyzed. The optimal macroscopically stable growth rate (without cracks and pits) and the way of achieving it are presented and discussed.

  15. Continuous monitoring of tissue growth inside a perfusion bioreactor by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bagnaninchi, P. O.; El Haj, A.; Yang, Y.

    2007-02-01

    Tissue engineering aims to create in vitro functional tissues that could ultimately be used as autologous implants. Considering the large number of parameters that have to be tested to optimize the tissue growth and to achieve a better understanding of tissue formation, relevant biological in vitro models are needed which can be monitored and characterized all along the different stages of tissue engineering: cell seeding, cell growth, extra-cellular matrix (ECM) deposition, matrix turn-over and tissue organization. We developed porous chitosan scaffolds (\\fgr 1.5mm) that enclose a 300?m microchannel to encourage fluid shear-stress stimulation and more specifically to support bundle formation for the specific case of tendon tissue engineering. These scaffolds were loaded in perfusion bioreactors and monitored during several days by optical coherence tomography (OCT). The fiber based time domain OCT employed a 1300nm superluminescent diode with a bandwith of 52 nm and a xyz resolution of 16*16*14 in free space. This set up allowed us to assess the volume fraction of cell seeded in the microchannels, and thus to optimize the seeding procedure. The cell growth and ECM deposition were successfully monitored at different time point as the channels were filled by newly formed material. Different scattering behaviors have been observed during cell growth and ECM production. The possibility to monitor continuously the scaffolds under perfusion will allow an easy discrimination of the parameters affecting the pre-tissue formation rate growth.

  16. Effective growth of dinoflagellate Prorocentrum minimum by cultivating the cells using municipal wastewater as nutrient source.

    PubMed

    Ho, Kin-Chung; Xu, Steven Jing-Liang; Wu, Kam-Chau; Lee, Fred Wang-Fat

    2013-01-01

    Several studies have been conducted worldwide in order to develop a more economical method for mass algal cultivation so that more cost-effective biomass production can be accessed. One of the directions is to reduce production costs by using wastewater as a nutrient source in algal cell cultivation. The growth ability of a red-tide causative dinoflagellate species, Prorocentrum minimum, in various concentrations of local urban wastewater was examined in this study. The highest exponential growth rate and maximum cell density (MCD) were achieved when autoclaved 10% wastewater was used for cell cultivation, although the cells could survive in 0.01-100% wastewater. Both growth rate and MCD of the cells in wastewater were found to be substantially higher than that in optimized L1 culture medium. This research highlights the potential of using wastewater as a cost-effective approach for mass cultivation of dinoflagellate cells with consequent production of valuable microalgal biomass. PMID:24037162

  17. Lemniscate growth

    E-print Network

    2012-05-08

    May 8, 2012 ... esting properties emerge while comparing lemniscate growth to Laplacian growth. ... Let TN be a fixed polynomial of degree N, and consider the one- parameter family of domains ...... 4202 E. Fowler Ave, PHY 114. Tampa, FL ...

  18. Recombinant collagen production optimization in Escherichia coli

    E-print Network

    Whittemore, Brett A

    2005-01-01

    An Escherichia coli-based collagen-production process was used to investigate several process optimization objectives for use at the industrial scale. The effect of cooling on fermentation growth kinetics was studied, with ...

  19. Changes in Self-Esteem across the First Year in College: The Role of Achievement Goals

    ERIC Educational Resources Information Center

    Shim, Sungok Serena; Ryan, Allison M.; Cassady, Jerrell

    2012-01-01

    This longitudinal study examined the effects of achievement goals on the growth trajectories of self-esteem during the first-year at a comprehensive public university. College freshmen (N = 311) were followed for one academic year with three time points. Between-individual differences and within-individual change in achievement goals were…

  20. Electrochemical nucleation and growth of copper

    NASA Astrophysics Data System (ADS)

    Radisic, Aleksandar

    2005-12-01

    The primary goal of this dissertation is to provide more insight into nucleation and growth processes during electrochemical deposition of copper on various metallic and semiconductor substrates. Electrodeposition is the current method used in forming copper interconnects in integrated circuits, primarily due to the ability of this technique to fill high aspect ratio features with complex geometries at high deposition rates, leading to high throughput and lower manufacturing costs. Important processing steps prior to electroplating involve the deposition of a thin diffusion barrier layer, to prevent copper diffusion into silicon, and deposition of a copper seed layer by means of physical vapor deposition (PVD). The copper seed layer provides good electrical contact and improved adhesion to the diffusion barrier layer. As the feature sizes in integrated circuits continue to decrease, industry is forced to explore the possibility of electrochemical deposition of high quality copper films without the use of a copper seed layer. It is not a priori clear that copper films deposited on diffusion barriers will follow the same growth mode as copper films deposited on copper seed layers, and whether it will be possible to achieve the "superfilling" effects without the copper seed layer. The growth of copper films on diffusion barrier materials occurs through Volmer-Weber (3D island) mode of growth. As a result, high nucleus densities are essential in depositing continuous thin films. For complex structures with small length scales, such as trenches and vias in integrated circuits, a detailed understanding of nucleation and growth, and the influence of parameters such as potential and solution chemistry on the deposition mechanism is critical in designing processes for obtaining the void-free features. The goal of our research is to improve the understanding of the electrochemical nucleation and growth processes necessary for successful electrodeposition of copper onto diffusion barrier layers, e.g. TiN, Ta, or TaN. The mechanism of nucleation and growth of copper from different plating solutions is studied using cyclic voltammetry and chronoamperometry. Deposited films are characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), in-situ, real-time, transmission electron microscopy (TEM). Using the results from these experiments we will optimize procedures for electrodeposition of continuous, high quality copper films on diffusion barrier layers.

  1. Risk modelling in portfolio optimization

    NASA Astrophysics Data System (ADS)

    Lam, W. H.; Jaaman, Saiful Hafizah Hj.; Isa, Zaidi

    2013-09-01

    Risk management is very important in portfolio optimization. The mean-variance model has been used in portfolio optimization to minimize the investment risk. The objective of the mean-variance model is to minimize the portfolio risk and achieve the target rate of return. Variance is used as risk measure in the mean-variance model. The purpose of this study is to compare the portfolio composition as well as performance between the optimal portfolio of mean-variance model and equally weighted portfolio. Equally weighted portfolio means the proportions that are invested in each asset are equal. The results show that the portfolio composition of the mean-variance optimal portfolio and equally weighted portfolio are different. Besides that, the mean-variance optimal portfolio gives better performance because it gives higher performance ratio than the equally weighted portfolio.

  2. Delayed growth

    MedlinePLUS

    Growth - slow (child 0 - 5 years); Weight gain - slow (child 0 - 5 years); Slow rate of growth; Retarded growth and development; ... A child should have regular, well-baby check-ups with a health care provider. These checkups are usually scheduled ...

  3. Achieving Maximal Speed of Solution Exchange for Patch Clamp Experiments

    PubMed Central

    Auzmendi, Jerónimo; Fernández Do Porto, Darío; Pallavicini, Carla; Moffatt, Luciano

    2012-01-01

    Background Resolving the kinetics of agonist binding events separately from the subsequent channel gating processes requires the ability of applying and removing the agonist before channel gating occurs. No reported system has yet achieved pulses shorter than 100 µs, necessary to study nicotinic ACh receptor or AMPA receptor activation. Methodology/Principal Findings Solution exchange systems deliver short agonist pulses by moving a sharp interface between a control and an experimental solution across a channel preparation. We achieved shorter pulses by means of an exchange system that combines a faster flow velocity, narrower partition between the two streams, and increased velocity and bandwidth of the movement of the interface. The measured response of the entire system was fed back to optimize the voltage signal applied to the piezoelectric actuator overcoming the spurious oscillations arising from the mechanical resonances when a high bandwidth driving function was applied. Optimization was accomplished by analyzing the transfer function of the solution exchange system. When driven by optimized command pulses the enhanced system provided pulses lasting 26 ± 1 µs and exchanging 93 ± 1% of the solution, as measured in the open tip of a patch pipette. Conclusions/Significance Pulses of this duration open the experimental study of the molecular events that occur between the agonist binding and the opening of the channel. PMID:22879927

  4. Teacher–Child Interactions and Children’s Achievement Trajectories Across Kindergarten and First Grade

    Microsoft Academic Search

    Timothy W. Curby; Sara E. Rimm-Kaufman; Claire Cameron Ponitz

    2009-01-01

    This study examined the extent to which the quality of teacher–child interactions and children’s achievement levels at kindergarten entry were associated with children’s achievement trajectories. Rural students (n = 147) were enrolled in a longitudinal study from kindergarten through first grade. Growth trajectories (initial level and slope) were modeled with hierarchical linear modeling for 3 areas of achievement: word reading,

  5. The Relationship among Achievement Motivation Orientations, Achievement Goals, and Academic Achievement and Interest: A Multiple Mediation Analysis

    ERIC Educational Resources Information Center

    Abd-El-Fattah, Sabry M.; Patrick, Rosan R.

    2011-01-01

    The aim of the present study is to examine the relationships among achievement motivation orientations and academic achievement and interest and whether achievement goals mediate these relationships. A sample of 503 students aged 14-16 years from 8 secondary schools in two Australia cities responded to a questionnaire package, comprising measures…

  6. Optimal nuclear waste burial policy under uncertainty

    Microsoft Academic Search

    Alain Ayong Le Kama; Mouez Fodha

    2009-01-01

    Abstract The aim of this paper is to study the optimal nuclear waste storage policy under,an uncertainty: the possibility that an accident might occur in the future. The framework,is an optimal,growth,model,with pollution disutility. Keywords: Nuclear Waste; Pollution; Growth; Uncertainty. Jel Class.: D90, Q53 Equippe, Université de Lille 1. E-mail: adayong@univ-paris1.fr.

  7. Development of Self-Concept, Delay of Gratification and Self-Control and Disadvantaged Preschool Children's Achievement Gain.

    ERIC Educational Resources Information Center

    Flynn, Timothy M.

    1985-01-01

    Disadvantaged preschool children attending a program of compensatory education were studied to determine if change in self-concept, delay of gratification, and exercise of self-control were related to growth in achievement. Girls displayed self-concept growth and a decline in delay of gratification, while boys showed growth in self-control.…

  8. Factors influencing epitaxial growth of three-dimensional Ge quantum dot crystals on pit-patterned Si substrate

    NASA Astrophysics Data System (ADS)

    Ma, Y. J.; Zhong, Z.; Yang, X. J.; Fan, Y. L.; Jiang, Z. M.

    2013-01-01

    We investigated the molecular beam epitaxy growth of three-dimensional (3D) Ge quantum dot crystals (QDCs) on periodically pit-patterned Si substrates. A series of factors influencing the growth of QDCs were investigated in detail and the optimized growth conditions were found. The growth of the Si buffer layer and the first quantum dot (QD) layer play a key role in the growth of QDCs. The pit facet inclination angle decreased with increasing buffer layer thickness, and its optimized value was found to be around 21°, ensuring that all the QDs in the first layer nucleate within the pits. A large Ge deposition amount in the first QD layer favors strain build-up by QDs, size uniformity of QDs and hence periodicity of the strain distribution; a thin Si spacer layer favors strain correlation along the growth direction; both effects contribute to the vertical ordering of the QDCs. Results obtained by atomic force microscopy and cross-sectional transmission electron microscopy showed that 3D ordering was achieved in the Ge QDCs with the highest ever areal dot density of 1.2 × 1010 cm-2, and that the lateral and the vertical interdot spacing were ˜10 and ˜2.5 nm, respectively.

  9. Transient disturbance growth in a corrugated channel

    NASA Astrophysics Data System (ADS)

    Szumbarski, J.; Floryan, J. M.

    2006-12-01

    Transient growth of small disturbances may lead to the initiation of the laminar turbulent transition process. Such growth in a two-dimensional laminar flow in a channel with a corrugated wall is analysed. The corrugation has a wavy form that is completely characterized by its wavenumber and amplitude. The maximum possible growth and the form of the initial disturbance that leads to such growth have been identified for each form of the corrugation. The form that leads to the largest growth for a given corrugation amplitude, i.e. the optimal corrugation, has been found. It is shown that the corrugation acts as an amplifier for disturbances that are approximately optimal in the smooth channel case but has little effect in the other cases. The interplay between the modal (asymptotic) instability and the transient growth, and the use of the variable corrugation for modulation of the growth are discussed.

  10. Growth Hormone Receptor in Growth

    Microsoft Academic Search

    Vivian Hwa

    \\u000a It has been approximately 20 years since the cloning and characterization of the human growth hormone (GH) receptor, GHR, gene. Cell-surface GHR binds circulating GH, which promotes postnatal growth by regulating the expression of insulin-like\\u000a growth factor (IGF)-I. Mutations in the GHR gene cause GH insensitivity (GHI) syndrome, also known as Laron syndrome, a syndrome characterized by severe postnatal growth

  11. Secular trends in growth.

    PubMed

    Cole, T J

    2000-05-01

    Since the 19th century there have been clearly documented secular trends to increasing adult height in most European countries, with current rates of 10-30 mm/decade. Over the same period menarcheal age has also fallen steeply, but has now stabilized at approximately 13 years and may be rising again. Height trends tend to be greater in childhood than in adulthood due to the associated advance in maturation, but no trends are apparent before the age of 2 years. In particular, birth-weight trends are small and different in shape from height trends. The adult height trend matches that at age 2 years, so that the increment in adult height has already been achieved by age 2 years. To try to identify factors relating to the secular trend, increased height gain in late infancy is hypothesized to be equivalent to a reduction in stunting, and stunting is thought to be caused by impaired growth in the long bones of the leg in later infancy. Leg growth may be regulated by the expression of growth-hormone receptors on the growth plates, which it is hypothesized are susceptible to the interaction between concurrent nutrition and the nominal growth rate set during pregnancy. The timing of menarche is also likely to be determined by some growth factor operating near the time of birth, which also affects later weight, but not height. PMID:10946801

  12. Double dendrite growth in solidification

    NASA Astrophysics Data System (ADS)

    Utter, Brian; Bodenschatz, E.

    2005-07-01

    We present experiments on the doublon growth morphology in directional solidification. Samples used are succinonitrile with small amounts of poly(ethylene oxide), acetone, or camphor as the solute. Doublons, or symmetry-broken dendrites, are generic diffusion-limited growth structures expected at large undercooling and low anisotropy. Low anisotropy growth is achieved by selecting a grain near the {111} plane leading to either seaweed (dense branching morphology) or doublon growth depending on experimental parameters. We find selection of doublons to be strongly dependent on solute concentration and sample orientation. Doublons are selected at low concentrations (low solutal undercooling) in contrast to the prediction of doublons at large thermal undercooling in pure materials. Doublons also exhibit preferred growth directions and changing the orientation of a specific doublonic grain changes the character and stability of the doublons. We observe transitions between seaweed and doublon growth with changes in concentration and sample orientation.

  13. Centre for Academic Achievement `Aiming High'

    E-print Network

    Humphrys, Mark

    in the classroom and what he might achieve in future life." Rachel Gillen, Christ the King Boys National School National School, Ballymun Astronomy Forensics Sport Science Chemistry Engineering Architecture ExperimentalCentre for Academic Achievement `Aiming High' Background The Centre for Academic Achievement (CAA

  14. Subgroup Achievement and Gap Trends: Vermont, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Vermont for 2010. Vermont's demographic profile is such that achievement trends could only be determined for white, male and female, and low-income student subgroups. In grade 8 (the only grade in which subgroup trends were analyzed by achievement level), the white, low-income,…

  15. The Intersection of Culture and Achievement Motivation

    ERIC Educational Resources Information Center

    Trumbull, Elise; Rothstein-Fisch, Carrie

    2011-01-01

    Achievement motivation is something that all members of the school community want to support in students, however few may recognize that it is influenced by culture. The very meaning of "achievement" is culturally variable, and the motives that students have for achieving may be quite different, depending upon their cultural background. The…

  16. Subgroup Achievement and Gap Trends: Oklahoma, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Oklahoma for 2010. Oklahoma made progress in narrowing achievement gaps for most major subgroups on the End-of-Instruction (EOI) test in Algebra I. Trends in achievement gaps could not be determined for other grades in math, or for any grades in reading, because the state…

  17. Examining the Stability of Achievement Goal Orientation

    ERIC Educational Resources Information Center

    Muis, Krista R.; Edwards, Ordene

    2009-01-01

    We examined stability and change in students' achievement goal orientations over varying tasks. Two naturalistic longitudinal studies were conducted in undergraduate courses. Students completed self-reports designed to measure their achievement goals. Achievement goals were measured four times: prior to two assignments and two exams. Four…

  18. Academic Achievement, Motivation and Possible Selves.

    ERIC Educational Resources Information Center

    Leondari, Angeliki; Syngollitou, Efi; Kiosseoglou, Grigoris

    1998-01-01

    Investigates the relationship between possible selves, academic achievement, motivation, and self-esteem with 289 high school students 14-15 years old. Results show that those who imagined themselves achieving as a result of hard work and referred to specific, elaborated positive selves outperformed the other groups in academic achievement and…

  19. Cognitive Style, Personal Needs and Academic Achievement.

    ERIC Educational Resources Information Center

    Poe, Charles A.; Bartz, Wayne H.

    This study was designed as an initial exploration of certain relationships of academic achievement, personal needs, and cognitive style. The relationship of the Edwards Personal Preference Schedule (EPPS) need for achievement and actual academic achievement (grade averages) in a sample of college students was explored. Also investigated was the…

  20. Predicting Academic Achievement with Cognitive Ability

    ERIC Educational Resources Information Center

    Rohde, Treena Eileen; Thompson, Lee Anne

    2007-01-01

    The purpose of the present study is to explain variation in academic achievement with general cognitive ability and specific cognitive abilities. Grade point average, Wide Range Achievement Test III scores, and SAT scores represented academic achievement. The specific cognitive abilities of interest were: working memory, processing speed, and…