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1

Optimism versus Pessimism and Academic Achievement Evaluation  

ERIC Educational Resources Information Center

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…

Harpaz-Itay, Yifat; Kaniel, Shlomo

2012-01-01

2

Creative potential, creative achievement, and personal growth.  

PubMed

We tested the idea that young people who have creative potential (are complex and unconventional) increase in intrapsychic awareness as they mature but often have difficulty with psychosocial growth, especially the development of a cohesive identity; and that for some women commitment to creative work solves the problem of psychosocial integration and leads to creative achievement. In a longitudinal sample of 109 women, these ideas were supported: Creative potential and creative achievement were both associated with intrapsychic growth but only creative achievement was associated with psychosocial growth. Regression analyses showed that the development of a cohesive identity from early to middle adulthood added to and interacted with creative potential in the prediction of creative achievement. PMID:10820679

Helson, R; Pals, J L

2000-02-01

3

Robust Growth-Optimal Portfolios - Optimization Online  

E-print Network

May 24, 2014 ... (SDP) whose size scales with the number of assets and the length of the investment horizon. ...... The classical growth-optimal portfolio is perceived as highly risky. ... In order to perform systematic contamination or stress test ...

2014-05-24

4

Achieving computational intelligence by resource optimization  

Microsoft Academic Search

This paper presents a general resource management and optimization (RMO) paradigm, known as the constrained resource planning (CRP) model, which has been shown broadly suitable for solving most planning and scheduling applications under stringent solution requirements, tightly interacting constraints, as well as restricted resource availability and utilization. By effectively deploying two domain-independent guiding principles - the most-constrained strategy for task

D. Y. Y. Yun

2002-01-01

5

Academic Optimism of Schools: A Force for Student Achievement  

Microsoft Academic Search

Researchers have been challenged to go beyond socioeconomic status in the search for school-level characteristics that make a difference in student achievement. The purpose of the present study was to identify a new construct, academic optimism, and then use it to explain student achievement while controlling for socioeconomic status, previous achievement, and urbanicity. The study focused on a diverse sample

Wayne K. Hoy; C. John Tarter; Anita Woolfolk Hoy

2006-01-01

6

Optimizing Production of Hydroquinone Achieves Increased Yield and Energy Efficiency  

E-print Network

Optimizing Production of Hydroquinone Achieves Increased Yield and Energy Efficiency Stephanie Goss Chemicals Development Division May 19, 2010 Presentation overview ? Project background ? Project definition ? Implementation of campaign... ? Large division (Chemicals Manufacturing) permitted labor sharing 2009 Campaign strategy operation ? Targeted maximum production rate (100% of capacity) with two extended shutdowns ? Spring shutdown ? 10 weeks ? Fall shutdown ? 3 weeks ? Performed...

Gross, S.

7

Academic optimism and student achievement in urban elementary schools  

Microsoft Academic Search

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 and multiple regression and factor analyses were used

Page A. Smith; Wayne K. Hoy

2007-01-01

8

The Role of Academic Achievement Growth in School Track Recommendations  

ERIC Educational Resources Information Center

Students in Germany are tracked into different forms of secondary schooling based on teachers' recommendations. The literature shows that school tracking is largely affected by academic achievement levels, but neglects the influence of individual achievement growth. The authors used data from the Berlin study ELEMENT (N = 2242) to characterize…

Caro, Daniel H.; Lenkeit, Jenny; Lehmann, Rainer; Schwippert, Knut

2009-01-01

9

Parent involvement and science achievement: A latent growth curve analysis  

NASA Astrophysics Data System (ADS)

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.

Johnson, Ursula Yvette

10

Translational Geroscience: Emphasizing function to achieve optimal longevity  

PubMed Central

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

Seals, Douglas R.; Melov, Simon

2014-01-01

11

Toward achieving optimal response: understanding and managing antidepressant side effects  

PubMed Central

The safety and tolerability of antidepressants have improved considerably over the past two decades, Nevertheless, antidepressant side effects are still common and problematic. The majority of patients treated with contemporary agents experience one or more bothersome side effects. These side effects often create barriers to achieving depressive remission, as well as to preventing relapse and recurrence. Clinicians tend to underestimate the prevalence of side effects, and as many as one quarter of patients discontinue their antidepressants because of difficult-to-tolerate side effects; others may continue on antidepressant therapy but experience diminished quality of life related to troublesome side effects. This article reviews the prevalence of side effects, the impact of side effects on treatment adherence, and methodological issues including the challenge of distinguishing side effects from residual depressive symptoms, discontinuation effects, and general medical problems. In addition, we address the most common side effects such as sexual dysfunction, gastrointestinal problems, sleep disturbance, apathy, and fatigue, and offer strategies for management that may help patients achieve optimal response to pharmacotherapy. PMID:19170398

Kelly, Karen; Posternak, Michael; Jonathan, E. Alpert

2008-01-01

12

Optimal control of crystal growth processes  

NASA Astrophysics Data System (ADS)

This work focuses on the optimal control of two typical processes in the context of industrial crystal growth. First, the annealing of bulk GaAs crystals is considered and an optimal control problem is solved in order to find optimised heating profiles for the furnace. A reduced order model for the annealing furnace has been developed in order to speed up the optimisation algorithm. As a second application, our control algorithm is used to optimise a VGF-process for growing GaAs crystals: the growth rate of the GaAs crystal is maximised under side conditions for the resulting thermal stress.

Metzger, Michael

2001-08-01

13

Optimizing growth in the preterm infant.  

PubMed

Most very low birth weight preterm infants experience postnatal growth failure in the neonatal ICU. In an attempt to minimize this phenomenon, the nutritional support of these infants has tended to become more aggressive in recent years and has become a focus of much study. Despite this attention, many questions remain unresolved. This article examines several of these issues, including the controversies regarding optimal postnatal growth velocity, early aggressive nutritional support, and the transition to enteral nutrition in preterm infants. PMID:19161873

Uhing, Michael R; Das, Utpala G

2009-03-01

14

Adaptation to Optimal Cell Growth through Self-Organized Criticality  

NASA Astrophysics Data System (ADS)

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; we consider the catalytic network dynamics over a wide range of environmental conditions, through the spontaneous regulation of nutrient transport into the cell. Furthermore, we find that the adaptability of cellular growth to reach a critical state depends only on the extent of environmental changes, while all chemical species in the cell exhibit correlated partial adaptation. These results are in remarkable agreement with the recent experimental observations of the present cells.

Furusawa, Chikara; Kaneko, Kunihiko

2012-05-01

15

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

PubMed

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

Skinner, Mark W

2012-07-01

16

Optimal Taxation in Models of Endogenous Growth  

Microsoft Academic Search

The authors study the problem of optimal taxation in three infinite-horizon, representative-agent endogenous growth models. The first model is a convex model in which physical and human capital are perfectly symmetric. The authors' second model incorporates elastic labor supply through a Lucas-style technology. Analysis of these two models points out the danger of assuming that government expenditures are exogenous. In

Larry E. Jones; Rodolfo E. Manuelli; Peter E. Rossi

1993-01-01

17

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

PubMed Central

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

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

2013-01-01

18

Aircraft optimization by a system approach: Achievements and trends  

NASA Technical Reports Server (NTRS)

Recently emerging methodology for optimal design of aircraft treated as a system of interacting physical phenomena and parts is examined. The methodology is found to coalesce into methods for hierarchic, non-hierarchic, and hybrid systems all dependent on sensitivity analysis. A separate category of methods has also evolved independent of sensitivity analysis, hence suitable for discrete problems. References and numerical applications are cited. Massively parallel computer processing is seen as enabling technology for practical implementation of the methodology.

Sobieszczanski-Sobieski, Jaroslaw

1992-01-01

19

Oystercatchers use colour preference to achieve longer-term optimality.  

PubMed Central

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

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

2002-01-01

20

A framework for optimization of crystal growth processes applied to VGF growth of fluorides  

NASA Astrophysics Data System (ADS)

We develop a flexible framework for optimization of crystal growth processes. This framework is based on an accurate and robust process model and combines two optimization loops. Adapting of model parameters and optimizing of process parameters.

Backofen, Rainer; Voigt, Axel; Wulff-Molder, Dirk

2005-02-01

21

Multiphase Nano-Composite Coatings for Achieving Energy Optimization  

SciTech Connect

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.

Dr. Jose Nainaparampil

2012-03-26

22

The Impact of Linking Distinct Achievement Test Scores on the Interpretation of Student Growth in Achievement  

ERIC Educational Resources Information Center

Changes to state tests impact the ability of State Education Agencies (SEAs) to monitor change in performance over time. The purpose of this study was to evaluate the Standardized Performance Growth Index (PGIz), a proposed statistical model for measuring change in student and school performance, across transitions in tests. The PGIz is a…

Airola, Denise Tobin

2011-01-01

23

Collective Responsibility, Academic Optimism, and Student Achievement in Taiwan Elementary Schools  

ERIC Educational Resources Information Center

Previous research indicates that collective efficacy, faculty trust in students and parents, and academic emphasis together formed a single latent school construct, called academic optimism. In the U.S., academic optimism has been proven to be a powerful construct that could effectively predict student achievement even after controlling for…

Wu, Hsin-Chieh

2012-01-01

24

Test Development with Performance Standards and Achievement Growth in Mind  

ERIC Educational Resources Information Center

Items on test score scales located at and below the Proficient cut score define the content area knowledge and skills required to achieve proficiency. Alternately, examinees who perform at the Proficient level on a test can be expected to be able to demonstrate that they have mastered most of the knowledge and skills represented by the items at…

Ferrara, Steve; Svetina, Dubravka; Skucha, Sylvia; Davidson, Anne H.

2011-01-01

25

Optimization of heating conditions during Cz BGO crystal growth  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

26

Optimal solutions for a free boundary problem for crystal growth  

E-print Network

Optimal solutions for a free boundary problem for crystal growth Pekka Neittaanm¨ aki Thomas I. Seidman Abstract. We consider a free boundary problem modeling the growth/dissolution of a crystal boundary problem corresponding to a model of growth (dissolution) of a radially symmetric crystal grain

Seidman, Thomas I.

27

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

ERIC Educational Resources Information Center

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…

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

2013-01-01

28

Role of well-being therapy in achieving a balanced and individualized path to optimal functioning.  

PubMed

A specific psychotherapeutic strategy for increasing psychological well-being and resilience, well-being therapy (WBT), based on Ryff's conceptual model, has been developed and tested in a number of randomized controlled trials. The findings indicate that flourishing and resilience can be promoted by specific interventions leading to a positive evaluation of one's self, a sense of continued growth and development, the belief that life is purposeful and meaningful, the possession of quality relations with others, the capacity to manage effectively one's life and a sense of self-determination. A decreased vulnerability to depression, mood swings and anxiety has been demonstrated after WBT in high-risk populations. School interventions based on the principles of WBT have been found to yield both promotion of well-being and decrease of distress compared with control groups. The differential technical characteristics and indications of WBT are described, with a special reference to the promotion of an individualized and balanced path to achieve optimal human functioning, avoiding the polarities in positive psychological dimensions. PMID:22570318

Ruini, Chiara; Fava, Giovanni A

2012-01-01

29

Problem Statement: Airports need to achieve carbon neutral growth operating an enterprise  

E-print Network

with limited control ·Carbon neutral growth by 2020 ·Baseline of 2005 ·Zero net growth of emissions by 2050Problem Statement: Airports need to achieve carbon neutral growth operating an enterprise Neutrality: ·Technology (Aircraft) ·Cost of changes and limitations on available capital for CO2 mitigation

30

A Longitudinal Investigation of Motivation and Secondary School Achievement Using Growth Mixture Modeling  

Microsoft Academic Search

Early identification of risk can support interventions to prevent academic failure. This study investigated patterns of evolution in achievement trajectories for 1,522 high school students in relation to initial achievement, student motivation, and key demographic characteristics. Growth mixture modeling identified 2 classes of longitudinal achievement patterns representing different trajectories toward leaving school either with or without qualifications. Negative motivation patterns

Flaviu A. Hodis; Luanna H. Meyer; John McClure; Kirsty F. Weir; Frank H. Walkey

2011-01-01

31

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

PubMed

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

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

2014-01-01

32

Shape optimization with the biological growth method: a parameter study  

Microsoft Academic Search

Studies the effect of parameters controlling the biological growth method by applying it to the classical optimization problem of a plate with a central hole under biaxial stress state. It has been found that the optimization character of the method depends strongly on the so-called reference stress. Depending on the magnitude of this parameter either a local or global optimum

A. Erman Tekkaya; Alper Güneri

1996-01-01

33

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

ERIC Educational Resources Information Center

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…

Johnson, Ursula Y.; Hull, Darrell M.

2014-01-01

34

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

ERIC Educational Resources Information Center

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

Henry, Kimberly L.

2010-01-01

35

Cognitive Predictors of Achievement Growth in Mathematics: A 5Year Longitudinal Study  

Microsoft Academic Search

The study's goal was to identify the beginning of 1st grade quantitative competencies that predict mathematics achievement start point and growth through 5th grade. Measures of number, counting, and arithmetic competencies were administered in early 1st grade and used to predict mathematics achievement through 5th (n = 177), while controlling for intelligence, working memory, and processing speed. Multilevel models revealed

David C. Geary

2011-01-01

36

Promising Practices in Professional Growth & Support: "Case Study of Achievement First"  

ERIC Educational Resources Information Center

Four organizations with promising practices in teacher Professional Growth & Support have significantly raised outcomes for low-income students. The charter management networks, Achievement First and Aspire Public Schools, and the two reform organizations, Teach Plus and Agile Mind, have successfully increased student achievement with a…

Education Resource Strategies, 2013

2013-01-01

37

A Longitudinal Investigation of Motivation and Secondary School Achievement Using Growth Mixture Modeling  

ERIC Educational Resources Information Center

Early identification of risk can support interventions to prevent academic failure. This study investigated patterns of evolution in achievement trajectories for 1,522 high school students in relation to initial achievement, student motivation, and key demographic characteristics. Growth mixture modeling identified 2 classes of longitudinal…

Hodis, Flaviu A.; Meyer, Luanna H.; McClure, John; Weir, Kirsty F.; Walkey, Frank H.

2011-01-01

38

Cognitive Predictors of Achievement Growth in Mathematics: A 5-Year Longitudinal Study  

ERIC Educational Resources Information Center

The study's goal was to identify the beginning of 1st grade quantitative competencies that predict mathematics achievement start point and growth through 5th grade. Measures of number, counting, and arithmetic competencies were administered in early 1st grade and used to predict mathematics achievement through 5th (n = 177), while controlling for…

Geary, David C.

2011-01-01

39

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

PubMed Central

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

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

2014-01-01

40

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

SciTech Connect

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.

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

2007-08-20

41

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

SciTech Connect

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.

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

42

Growth without pain: the world can achieve sustained economic growth by reducing waste  

Microsoft Academic Search

The case is presented for eliminating America's wasteful methods of manufacturing, distributing, and consuming goods as a prerequisite for continuing world economic growth. While waste is difficult to define, there is a growing awareness that it is costly and that some external discipline is required to effect a change in lifestyles. A cost\\/benefit analysis of waste management would indicate the

van Dam

1978-01-01

43

How to Achieve the Optimal DMT of Selective Fading MIMO Channels?  

E-print Network

In this paper, we consider a particular class of selective fading channel corresponding to a channel that is selective either in time or in frequency. For this class of channel, we propose a systematic way to achieve the optimal DMT derived in Coronel and B\\"olcskei, IEEE ISIT, 2007 by extending the non-vanishing determinant (NVD) criterion to the selective channel case. A new code construction based on split NVD parallel codes is then proposed to satisfy the NVD parallel criterion. This result is of significant interest not only in its own right, but also because it settles a long-standing debate in the literature related to the optimal DMT of selective fading channels.

Mroueh, Lina

2010-01-01

44

Urban Middle-Grade Student Mathematics Achievement Growth under Comprehensive School Reform  

ERIC Educational Resources Information Center

Recognizing the need to implement standards-based instructional materials with school-wide coherence led some Philadelphia schools to adopt whole-school reform (WSR) models during the late 1990s. The authors report on the relation between mathematics achievement growth for middle-grade students on the Pennsylvania System of School Assessments and…

Mac Iver, Martha Abele; Mac Iver, Douglas J.

2009-01-01

45

Growth in Reading Achievement of Students with Disabilities, Ages 7 to 17  

ERIC Educational Resources Information Center

Using data from the Special Education Elementary Longitudinal Study (SRI International, 2002), this study estimated reading growth trajectories in a nationally representative sample of 3,421 students with disabilities ages 7 to 17 representing 11 federal disability categories. Reading achievement in all disability categories increased with age,…

Wei, Xin; Blackorby, Jose; Schiller, Ellen

2011-01-01

46

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

NASA Astrophysics Data System (ADS)

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.

Muller, Patricia Ann

47

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

SciTech Connect

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.

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

2000-11-16

48

Measuring and evaluating school performance: an investigation of status and growth-based achievement indicators.  

PubMed

Several school performance indices were evaluated using achievement data from multiple longitudinally matched middle school student cohorts in a large district in the southwestern United States. Measures designed to index the within-cohort achievement status and growth of students as well as the status and growth-based changes that occur over years between different student cohorts were studied. Within- and between-cohort status and growth-based estimates of school performance were generated by applying simple and relatively complex statistical models to the longitudinal time-series data obtained on students. Results indicated that within-cohort status-based estimates were closely related to student demographics and between-cohort estimates were associated with cohort enrollment size and initial performance level. These results suggest that schools may often be rewarded and penalized on the basis of factors over which school personnel have limited or no control. Implications for the measurement and evaluation of school performance are discussed. PMID:18596304

Zvoch, Keith; Stevens, Joseph J

2008-12-01

49

Birth Weight and Infant Growth: Optimal Infant Weight Gain versus Optimal Infant Weight  

Microsoft Academic Search

Objective: Infant growth assessment often focuses on “optimal” infant weights and lengths at specific ages, while de-emphasizing infant\\u000a weight gain. Objective of this study was to examine infant growth patterns by measuring infant weight gain relative to birth\\u000a weight. Methods: We conducted this study based on data collected in a prospective cohort study including 3,302 births with follow up examinations

Xu Xiong; Joan Wightkin; Jeanette H. Magnus; Gabriella Pridjian; Juan M. Acuna; Pierre Buekens

2007-01-01

50

Cognitive Predictors of Achievement Growth in Mathematics: A Five Year Longitudinal Study  

PubMed Central

The study's goal was to identify the beginning of first grade quantitative competencies that predict mathematics achievement start point and growth through fifth grade. Measures of number, counting, and arithmetic competencies were administered in early first grade and used to predict mathematics achievement through fifth (n = 177), while controlling for intelligence, working memory, and processing speed. Multilevel models revealed intelligence, processing speed, and the central executive component of working memory predicted achievement or achievement growth in mathematics and, as a contrast domain, word reading. The phonological loop was uniquely predictive of word reading and the visuospatial sketch pad of mathematics. Early fluency in processing and manipulating numerical set size and Arabic numerals, accurate use of sophisticated counting procedures for solving addition problems, and accuracy in making placements on a mathematical number line were uniquely predictive of mathematics achievement. Use of memory-based processes to solve addition problems predicted mathematics and reading achievement but in different ways. The results identify the early quantitative competencies that uniquely contribute to mathematics learning. PMID:21942667

Geary, David C.

2011-01-01

51

A Study of the Effects of the Accelerated Reader Program on Fifth Grade Students' Reading Achievement Growth  

ERIC Educational Resources Information Center

The purpose of this study was to compare the reading achievement growth of fifth grade students following a year of participation in the Accelerated Reader program with the reading achievement growth of fifth grade students who did not participate in the Accelerated Reader program. The Terra Nova standardized achievement test was used as the…

Melton, Cindy M.; Smothers, Bobbie C.; Anderson, Eugene; Fulton, Ray; Replogle, William H.; Thomas, Lisa

2004-01-01

52

Comparison of linear and nonlinear optimal perturbation transient growth in plane Couette flow  

NASA Astrophysics Data System (ADS)

Previous approaches to the question of transient growth have focused upon the study of linearised disturbances, with the assumption that it is the growth in the linear regime of linear optimal perturbations (LOPs) that nevertheless lead to a nonlinear regime and hence trigger the transition to turbulence. In this study we take a different approach by considering the full nonlinear problem. We look to extend the work considering pipe flow of Pringle (C. C. T. Pringle Ph.D. Bristol 2009) and use variational techniques to examine both the spatial structure and the normalised kinetic energy growth (gain) achieved by nonlinear optimal perturbations (NLOPs) in plane Couette flow. We show that in certain circumstances the gain achieved by the NLOP is significantly larger and has a noticeably different (and more complex) spatial structure from its counterpart LOP. We investigate the dependence on initial perturbation energy of the maximum predicted gain for selected Reynolds numbers and optimization times and propose that these inherently nonlinear structures may well be more significant in the transition to turbulence than LOPs.

Rabin, S. M. E.; Caulfield, C. P.; Kerswell, R. R.

2010-11-01

53

Numerical Optimization of the Thermal Field in Bridgman Detached Growth  

NASA Technical Reports Server (NTRS)

The global modeling of the thermal field in two vertical Bridgman-like crystal growth configurations, has been performed to get optimal thermal conditions for a successful detached growth of Ge and CdTe crystals. These computations are performed using the CrysMAS code and expand upon our previous analysis [1] that propose a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. The analysis of the vertical Bridgman configuration with two heaters, used by Palosz et al. for the detached growth of Ge, shows, consistent with their results, that the large wetting angle of germanium on boron nitride surfaces was an important factor to promote a successful detached growth. Our computations predict that by initiating growth much higher into the hot zone of the furnace, the thermal conditions will be favorable for continued detachment even for systems that did not exhibit high contact angles. The computations performed for a vertical gradient freeze configuration with three heaters representative of that used for the detached growth of CdTe, show favorable thermal conditions for dewetting during the entirely growth run described. Improved thermal conditions are also predicted for coated silica crucibles when the solid-liquid interface advances higher into the hot zone during the solidification process. The second set of experiments on CdTe growth described elsewhere has shown the reattachment of the crystal to the crucible after few centimeters of dewetted growth. The thermal modeling of this configuration shows a second solidification front appearing at the top of the sample and approaching the middle line across the third heater. In these conditions, the crystal grows detached from the bottom, but will be attached to the crucible in the upper part because of the solidification without gap in this region. The solidification with two interfaces can be avoided when the top of the sample is positioned below the middle position of the third furnace.

Stelian, C.; Volz, M. P.; Derby, J. J.

2009-01-01

54

The Optimal Growth of Tropical Sea Surface Temperature Anomalies  

Microsoft Academic Search

It is argued from SST observations for the period 1950-90 that the tropical Indo-Pacific ocean-atmosphere system may be described as a stable linear dynamical system driven by spatially coherent Gaussian white noise. Evidence is presented that the predictable component of SST anomaly growth is associated with the constructive interference of several damped normal modes after an optimal initial structure is

Cécile Penland; Prashant D. Sardeshmukh

1995-01-01

55

CCMR: Growth Parameter Optimization and Contact Printing of Germanium Nanowires  

NSDL National Science Digital Library

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.

Blood-Forsythe, Martin A.

2008-08-15

56

Optimizing amorphous indium zinc oxide film growth for low residual stress and high electrical conductivity  

NASA Astrophysics Data System (ADS)

With recent advances in flexible electronics, there is a growing need for transparent conductors with optimum conductivity tailored to the application and nearly zero residual stress to ensure mechanical reliability. Within amorphous transparent conducting oxide (TCO) systems, a variety of sputter growth parameters have been shown to separately impact film stress and optoelectronic properties due to the complex nature of the deposition process. We apply a statistical design of experiments (DOE) approach to identify growth parameter-material property relationships in amorphous indium zinc oxide (a-IZO) thin films and observed large, compressive residual stresses in films grown under conditions typically used for the deposition of highly conductive samples. Power, growth pressure, oxygen partial pressure, and RF power ratio (RF/(RF + DC)) were varied according to a full-factorial test matrix and each film was characterized. The resulting regression model and analysis of variance (ANOVA) revealed significant contributions to the residual stress from individual growth parameters as well as interactions of different growth parameters, but no conditions were found within the initial growth space that simultaneously produced low residual stress and high electrical conductivity. Extrapolation of the model results to lower oxygen partial pressures, combined with prior knowledge of conductivity-growth parameter relationships in the IZO system, allowed the selection of two promising growth conditions that were both empirically verified to achieve nearly zero residual stress and electrical conductivities >1480 S/cm. This work shows that a-IZO can be simultaneously optimized for high conductivity and low residual stress.

Kumar, Mukesh; Sigdel, A. K.; Gennett, T.; Berry, J. J.; Perkins, J. D.; Ginley, D. S.; Packard, C. E.

2013-10-01

57

Journal of Crystal Growth 280 (2005) 587593 Optimization of the mineral content in polymeric gels  

E-print Network

Journal of Crystal Growth 280 (2005) 587­593 Optimization of the mineral content in polymeric gels that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca/P molar ratio of 1 other than the formation and growth of hydroxyapatite crystals. Therefore, the optimal level

Azad, Abdul-Majeed

58

Buffer insertion is an increasingly critical optimization for achieving timing closure, and the number of buffers required  

E-print Network

ABSTRACT Buffer insertion is an increasingly critical optimization for achieving timing closure, and the number of buffers required increases significantly with technology migration. It is imperative for an automated buffer insertion algorithm to be able to efficiently optimize tens of thousands of nets. One must

Hu, Jiang

59

hal-00166626,version1-10Aug2007 MIMO-OFDM OPTIMAL DECODING AND ACHIEVABLE INFORMATION RATES  

E-print Network

hal-00166626,version1-10Aug2007 MIMO-OFDM OPTIMAL DECODING AND ACHIEVABLE INFORMATION RATES UNDER Optimal decoding of bit interleaved coded modulation (BICM) MIMO-OFDM where an imperfect channel estimate estimation. Numerical re- sults over Rayleigh block fading MIMO-OFDM channels show that the proposed decoder

Paris-Sud XI, Université de

60

Reversible masking using low-molecular-weight neutral lipids to achieve optimal-targeted delivery.  

PubMed

Intravenous injection of therapeutics is required to effectively treat or cure metastatic cancer, certain cardiovascular diseases, and other acquired or inherited diseases. Using this route of delivery allows potential uptake in all disease targets that are accessed by the bloodstream. However, normal tissues and organs also have the potential for uptake of therapeutic agents. Therefore, investigators have used targeted delivery to attempt delivery solely to the target cells; however, use of ligands on the surface of delivery vehicles to target specific cell surface receptors is not sufficient to avoid nonspecific uptake. PEGylation has been used for decades to try to avoid nonspecific uptake but suffers from many problems known as "The PEGylation Dilemma." We have solved this dilemma by replacing PEGylation with reversible masking using low-molecular-weight neutral lipids in order to achieve optimal-targeted delivery solely to target cells. Our paper will focus on this topic. PMID:22655199

Templeton, Nancy Smyth; Senzer, Neil

2012-01-01

61

Reversible Masking Using Low-Molecular-Weight Neutral Lipids to Achieve Optimal-Targeted Delivery  

PubMed Central

Intravenous injection of therapeutics is required to effectively treat or cure metastatic cancer, certain cardiovascular diseases, and other acquired or inherited diseases. Using this route of delivery allows potential uptake in all disease targets that are accessed by the bloodstream. However, normal tissues and organs also have the potential for uptake of therapeutic agents. Therefore, investigators have used targeted delivery to attempt delivery solely to the target cells; however, use of ligands on the surface of delivery vehicles to target specific cell surface receptors is not sufficient to avoid nonspecific uptake. PEGylation has been used for decades to try to avoid nonspecific uptake but suffers from many problems known as “The PEGylation Dilemma.” We have solved this dilemma by replacing PEGylation with reversible masking using low-molecular-weight neutral lipids in order to achieve optimal-targeted delivery solely to target cells. Our paper will focus on this topic. PMID:22655199

Templeton, Nancy Smyth; Senzer, Neil

2012-01-01

62

Restricted and Repetitive Behaviors in Individuals with a History of ASDs Who Have Achieved Optimal Outcomes.  

PubMed

Studies of autism spectrum disorders (ASDs) suggest that restricted and repetitive behaviors (RRBs) are particularly difficult to remediate. We examined present and past RRBs in 34 individuals who achieved optimal outcomes (OOs; lost their ASD diagnosis), 45 high-functioning individuals with ASD (HFA) and 34 typically developing (TD) peers. The OO group exhibited minimal residual RRBs at the time of the study. All OO participants were reported to have at least one RRB in early childhood and almost 90 % met the RRB cutoff for ASD in early childhood, but RRBs were not more present in the OO than the TD group at the time of the study. History of RRBs in the HFA and OO groups differed only in oversensitivity to noise and insistence on sameness. Reports of current behavior indicated that RRB's had almost totally disappeared in the OO group. Thus, although RRB's were present in the OO group in childhood, they resolved along with social and communication deficits. PMID:25030967

Troyb, Eva; Orinstein, Alyssa; Tyson, Katherine; Eigsti, Inge-Marie; Naigles, Letitia; Fein, Deborah

2014-12-01

63

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

PubMed Central

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

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

2011-01-01

64

Achieving conservation when opportunity costs are high: optimizing reserve design in Alberta's oil sands region.  

PubMed

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

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

2011-01-01

65

The large diameter and fast growth of self-organized TiO2 nanotube arrays achieved via electrochemical anodization.  

PubMed

We have carried out a detailed investigation of the effect of water content on the electrochemical anodization of Ti in electrolytes consisting of ammonium fluoride, water, and ethylene glycol. We have explored the possible growth of ordered TiO(2) nanotubes in the electrolyte with water concentrations from 1 to 100 vol% and the applied voltage from 10 to 150 V, where large diameter (approximately 600 nm) and fast growth rate (approximately 100 microm h(-1)) have been successfully realized for the self-organized TiO(2) nanotube arrays. The achievement benefits from the clear understanding of the effects of both the water content and the anodization voltage on the formation of TiO(2) nanotube arrays. We have further shown crystalline formation of TiO(2) nanotubes by simple thermal annealing. The mechanisms of the effect of the water content on the diameter and growth rate revealed here should establish a basis for further optimization of the TiO(2) nanotube geometries. PMID:19966387

Yin, H; Liu, H; Shen, W Z

2010-01-22

66

Evaluating and optimizing horticultural regimes in space plant growth facilities  

NASA Astrophysics Data System (ADS)

In designing innovative Space Plant Growth Facilities (SPGF) for long duration space f ightl various limitations must be addressed including onboard resources: volume, energy consumption, heat transfer and crew labor expenditure. The required accuracy in evaluating onboard resources by using the equivalent mass methodology and applying it to the design of such facilities is not precise. This is due to the uncertainty of the structure and not completely understanding of the properties of all associated hardware, including the technology in these systems. We present a simple criteria of optimization for horticultural regimes in SPGF: Qmax = max [M · (EBI) 2 / (V · E · T) ], where M is the crop harvest in terms of total dry biomass in the plant growth system; EBI is the edible biomass index (harvest index), V is a volume occupied by the crop; E is the crop light energy supply during growth; T is the crop growth duration. The criterion reflects directly on the consumption of onboard resources for crop production. We analyzed the efficiency of plant crops and the environmental parameters by examining the criteria for 15 salad and 12 wheat crops from the data in the ALS database at Kennedy Space Center. Some following conclusion have been established: 1. The technology involved in growing salad crops on a cylindrical type surface provides a more meaningful Q-criterion; 2. Wheat crops were less efficient than leafy greens (salad crops) when examining resource utilization; 3. By increasing light intensity of the crop the efficiency of the resource utilization could decrease. Using the existing databases and Q-criteria we have found that the criteria can be used in optimizing design and horticultural regimes in the SPGF.

Berkovich, Y.; Chetirkin, R.; Wheeler, R.; Sager, J.

67

Legionella pneumophilaRequires Polyamines for Optimal Intracellular Growth ?  

PubMed Central

The Gram-negative intracellular pathogen Legionella pneumophilareplicates in a membrane-bound compartment known as the Legionella-containing vacuole (LCV), into which it abundantly releases its chaperonin, HtpB. To determine whether HtpB remains within the LCV or reaches the host cell cytoplasm, we infected U937 human macrophages and CHO cells with L. pneumophilaexpressing a translocation reporter consisting of the Bordetella pertussisadenylate cyclase fused to HtpB. These infections led to increased cyclic AMP levels, suggesting that HtpB reaches the host cell cytoplasm. To identify potential functions of cytoplasmic HtpB, we expressed it in the yeast Saccharomyces cerevisiae, where HtpB induced pseudohyphal growth. A yeast-two-hybrid screen showed that HtpB interacted with S-adenosylmethionine decarboxylase (SAMDC), an essential yeast enzyme (encoded by SPE2) that is required for polyamine biosynthesis. Increasing the copy number of SPE2induced pseudohyphal growth in S. cerevisiae; thus, we speculated that (i) HtpB induces pseudohyphal growth by activating polyamine synthesis and (ii) L. pneumophilamay require exogenous polyamines for growth. A pharmacological inhibitor of SAMDC significantly reduced L. pneumophilareplication in L929 mouse cells and U937 macrophages, whereas exogenously added polyamines moderately favored intracellular growth, confirming that polyamines and host SAMDC activity promote L. pneumophilaproliferation. Bioinformatic analysis revealed that most known enzymes required for polyamine biosynthesis in bacteria (including SAMDC) are absent in L. pneumophila, further suggesting a need for exogenous polyamines. We hypothesize that HtpB may function to ensure a supply of polyamines in host cells, which are required for the optimal intracellular growth of L. pneumophila. PMID:21742865

Nasrallah, Gheyath K.; Riveroll, Angela L.; Chong, Audrey; Murray, Lois E.; Lewis, P. Jeffrey; Garduno, Rafael A.

2011-01-01

68

Optimization of biomass composition explains microbial growth-stoichiometry relationships  

USGS Publications Warehouse

Integrating microbial physiology and biomass stoichiometry opens far-reaching possibilities for linking microbial dynamics to ecosystem processes. For example, the growth-rate hypothesis (GRH) predicts positive correlations among growth rate, RNA content, and biomass phosphorus (P) content. Such relationships have been used to infer patterns of microbial activity, resource availability, and nutrient recycling in ecosystems. However, for microorganisms it is unclear under which resource conditions the GRH applies. We developed a model to test whether the response of microbial biomass stoichiometry to variable resource stoichiometry can be explained by a trade-off among cellular components that maximizes growth. The results show mechanistically why the GRH is valid under P limitation but not under N limitation. We also show why variability of growth rate-biomass stoichiometry relationships is lower under P limitation than under N or C limitation. These theoretical results are supported by experimental data on macromolecular composition (RNA, DNA, and protein) and biomass stoichiometry from two different bacteria. In addition, compared to a model with strictly homeostatic biomass, the optimization mechanism we suggest results in increased microbial N and P mineralization during organic-matter decomposition. Therefore, this mechanism may also have important implications for our understanding of nutrient cycling in ecosystems.

Franklin, O.; Hall, E.K.; Kaiser, C.; Battin, T.J.; Richter, A.

2011-01-01

69

Evaluating and optimizing horticultural regimes in space plant growth facilities  

NASA Technical Reports Server (NTRS)

In designing innovative space plant growth facilities (SPGF) for long duration space flight, various limitations must be addressed including onboard resources: volume, energy consumption, heat transfer and crew labor expenditure. The required accuracy in evaluating on board resources by using the equivalent mass methodology and applying it to the design of such facilities is not precise. This is due to the uncertainty of the structure and not completely understanding the properties of all associated hardware, including the technology in these systems. We present a simple criteria of optimization for horticultural regimes in SPGF: Qmax = max [M x (EBI)2/(V x E x T], where M is the crop harvest in terms of total dry biomass in the plant growth system; EBI is the edible biomass index (harvest index), V is volume occupied by the crop; E is the crop light energy supply during growth; T is the crop growth duration. The criterion reflects directly on the consumption of onboard resources for crop production. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Berkovich, Y. A.; Chetirkin, P. V.; Wheeler, R. M.; Sager, J. C.

2004-01-01

70

Growth or reproduction: emergence of an evolutionary optimal strategy  

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

71

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

72

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

73

Release optimization of epidermal growth factor from PLGA microparticles.  

PubMed

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

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

2014-08-01

74

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

ERIC Educational Resources Information Center

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…

Chang, I-Hua

2011-01-01

75

Optimizing bioethanol production by regulating yeast growth energy.  

PubMed

The goal of this work is to optimize production of bio-ethanol by fermentation through regulating yeast growth energy (YGE), and provide the mechanism of ethanol production from food-waste leachate (FWL) using yeast (S. cerevisiae) as inoculums to be predictable and controllable. The wide range of reduced sugar concentration (RSC) which is commonly administered from low (35 g per liter) to very high (100 g per liter) is responsible for costs increasing besides risks of FWL contamination and death of yeast cells. A mathematical model is presented to describe yeast growth energy (YGE) due to RSC doses along with predicting the amounts of ethanol yield by each dose to identify the optimum one. Simulations of the presented model showed that YGE, energy intake (EI), and their produced ethanol energy (PEE) are always balanced during fermentation process according to the law of conservation of energy. For a better fermentation rate in a continuous process and a large-scale production; YGE should be less than half of EI and more than its quarter (i.e. [Formula: see text]) which keeps the residual energy less than YGE to avoid risks of osmotic stresses or aging of cells allowing the survival of all yeast cells as long as possible to maximize ethanol production and decrease productivity costs. PMID:24294340

Moawad, Emad Y

2012-12-01

76

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

PubMed Central

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

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

2013-01-01

77

Inverse-optimized 3D conformal planning: Minimizing complexity while achieving equivalence with beamlet IMRT in multiple clinical sites  

PubMed Central

Purpose: Inverse planned intensity modulated radiation therapy (IMRT) has helped many centers implement highly conformal treatment planning with beamlet-based techniques. The many comparisons between IMRT and 3D conformal (3DCRT) plans, however, have been limited because most 3DCRT plans are forward-planned while IMRT plans utilize inverse planning, meaning both optimization and delivery techniques are different. This work avoids that problem by comparing 3D plans generated with a unique inverse planning method for 3DCRT called inverse-optimized 3D (IO-3D) conformal planning. Since IO-3D and the beamlet IMRT to which it is compared use the same optimization techniques, cost functions, and plan evaluation tools, direct comparisons between IMRT and simple, optimized IO-3D plans are possible. Though IO-3D has some similarity to direct aperture optimization (DAO), since it directly optimizes the apertures used, IO-3D is specifically designed for 3DCRT fields (i.e., 1–2 apertures per beam) rather than starting with IMRT-like modulation and then optimizing aperture shapes. The two algorithms are very different in design, implementation, and use. The goals of this work include using IO-3D to evaluate how close simple but optimized IO-3D plans come to nonconstrained beamlet IMRT, showing that optimization, rather than modulation, may be the most important aspect of IMRT (for some sites). Methods: The IO-3D dose calculation and optimization functionality is integrated in the in-house 3D planning/optimization system. New features include random point dose calculation distributions, costlet and cost function capabilities, fast dose volume histogram (DVH) and plan evaluation tools, optimization search strategies designed for IO-3D, and an improved, reimplemented edge/octree calculation algorithm. The IO-3D optimization, in distinction to DAO, is designed to optimize 3D conformal plans (one to two segments per beam) and optimizes MLC segment shapes and weights with various user-controllable search strategies which optimize plans without beamlet or pencil beam approximations. IO-3D allows comparisons of beamlet, multisegment, and conformal plans optimized using the same cost functions, dose points, and plan evaluation metrics, so quantitative comparisons are straightforward. Here, comparisons of IO-3D and beamlet IMRT techniques are presented for breast, brain, liver, and lung plans. Results: IO-3D achieves high quality results comparable to beamlet IMRT, for many situations. Though the IO-3D plans have many fewer degrees of freedom for the optimization, this work finds that IO-3D plans with only one to two segments per beam are dosimetrically equivalent (or nearly so) to the beamlet IMRT plans, for several sites. IO-3D also reduces plan complexity significantly. Here, monitor units per fraction (MU/Fx) for IO-3D plans were 22%–68% less than that for the 1 cm?×?1 cm beamlet IMRT plans and 72%–84% than the 0.5 cm?×?0.5 cm beamlet IMRT plans. Conclusions: The unique IO-3D algorithm illustrates that inverse planning can achieve high quality 3D conformal plans equivalent (or nearly so) to unconstrained beamlet IMRT plans, for many sites. IO-3D thus provides the potential to optimize flat or few-segment 3DCRT plans, creating less complex optimized plans which are efficient and simple to deliver. The less complex IO-3D plans have operational advantages for scenarios including adaptive replanning, cases with interfraction and intrafraction motion, and pediatric patients. PMID:22755717

Fraass, Benedick A.; Steers, Jennifer M.; Matuszak, Martha M.; McShan, Daniel L.

2012-01-01

78

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

Microsoft Academic Search

Yb:S-FAP [Yb{sup 3+}:Sr(PO)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-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

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

2007-01-01

79

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

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

80

Optimism, Social Support, and Coping Strategies As Factors Contributing to Posttraumatic Growth: A Meta-Analysis  

Microsoft Academic Search

This meta-analytic review examines the role of optimism, social support, and coping strategies in contributing to posttraumatic growth. Results from 103 studies showed that all three systems of variables yielded significant effect sizes. Religious coping and positive reappraisal coping produced the largest effect sizes. Social support, seeking social support coping, spirituality, and optimism were moderately related to posttraumatic growth. Acceptance

Gabriele Prati; Luca Pietrantoni

2009-01-01

81

Journal of Environmental Economics and Management 48 (2004) 723741 Uncertain climate thresholds and optimal economic growth  

E-print Network

thermohaline circulation collapse), parameter uncertainty, and learning in an optimal economic growth model; Climate thresholds; Abrupt climate change; North Atlantic thermohaline circulation; Optimal growth model thresholds such as a collapse of the ocean thermohaline circulation (e.g., [46,51]). In contrast, many

Keller, Klaus

82

Use of genetic algorithms for the development and optimization of crystal growth processes  

NASA Astrophysics Data System (ADS)

This paper demonstrates that the combination of a genetic algorithm (GA) and a thermal modeling tool can be useful and efficient for the development and optimization of crystal growth processes. Results are shown for two typical semiconductor crystal growth models: VGF-GaAs and Si-Czochralski. The VGF case demonstrates the automatic development of an entire growth process, including optimization of the furnace itself and of the heater temperature settings under various constraints. In the Czochralski model, an optimization of the heat shield configuration has been conducted in order to demonstrate how the GA can be applied to geometry optimization tasks.

Fühner, T.; Jung, T.

2004-05-01

83

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

Microsoft Academic Search

Yb:S-FAP [Yb3+:Sr5(PO4)3F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF2-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

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

2008-01-01

84

Optimization of VGF-growth of GaAs crystals by the aid of numerical modelling  

Microsoft Academic Search

The VGF growth of Si-doped GaAs crystals is improved considerably by optimizing the design of the crucible support and the temperature profile during the growth run. Inverse simulation with the software program CrysVUN++ was used for this procedure. The criteria for the optimized conditions are flat phase boundaries and low thermal stress during the whole growth run. The crystals which

G. Muller; B. Birkmann

2002-01-01

85

Understanding the mathematics and science achievement and growth trajectories of high ability high school students using hierarchical linear modeling  

NASA Astrophysics Data System (ADS)

This study used longitudinal data and individual, family, and academic-related matriculation variables to examine trends in initial status and growth trajectories in overall academics, mathematics, and science achievement among 224 high ability high school Asian students. Results indicate that females have an advantage in both initial status and growth rates in overall academics and science. None of the family variables entered in the models were found to be significantly related to overall academics grade point average. All available matriculation variables entered into the models explained less than or at most about half the variance in initial achievement status and growth rate in overall academics and science but not in mathematics. These results strongly imply that other factors, notably family and school and/or classroom-related variables, not measured by the ones used in the models could explain the expected variance in initial status and growth rate of the students especially in Mathematics.

Belen-Ferrer, Bellasanta

86

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

E-print Network

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

Lieth, J. Heinrich

87

Optimization of plant growth-promoting bacteria-assisted phytostabilization of mine tailings  

E-print Network

Optimization of plant growth-promoting bacteria-assisted phytostabilization of mine tailings have indicated that plant growth-promoting bacteria (PGPB) can improve revegetation of arid mine establishment which increases reme- diation costs. Plant growth-promoting bacteria (PGPB) have found wide use

Palmer, Michael W.

88

Relative growth rates and the grazing optimization hypothesis  

Microsoft Academic Search

A mathematical analysis of the changes in plant relative growth rates necessary to increase aboveground production following grazing was conducted. The equation derived gives an isoline where production of a grazed and ungrazed plant will be the same. The equation has four variables (mean shoot relative growth rate, change in relative growth rate after grazing, grazing intensity, and recovery time)

D. W. Hilbert; D. M. Swift; J. K. Detling; M. I. Dyer

1981-01-01

89

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

PubMed

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

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

2014-11-01

90

Logical definability and asymptotic growth in optimization and counting problems  

SciTech Connect

There has recently been a great deal of interest in the relationship between logical definability and NP-optimization problems. Let MS{sub n} (resp. MP{sub n}) be the class of problems to compute, for given a finite structure A, the maximum number of tuples {bar x} in A satisfying a {Sigma}{sub n} (resp. II{sub n}) formula {psi}({bar x}, {bar S}) as {bar S} ranges over predicates on A. Kolaitis and Thakur showed that the classes MS{sub n} and MP{sub n} collapse to a hierarchy of four levels. Papadimitriou and Yannakakis previously showed that problems in the two lowest levels MS{sub 0} and MS{sub 1} (which they called Max Snp and Max Np) are approximable to within a contrast factor in polynomial time. Similarly, Saluja, Subrahmanyam, and Thakur defined SS{sub n} (resp. SP{sub n}) to be the class of problems to compute, for given a finite structure A, the number of tuples ({bar T}, {bar S}) satisfying a given {Sigma}{sub n} (resp. II{sub n}) formula {psi}({bar T}, {bar c}) in A. They showed that the classes SS{sub n} and SP{sub n} collapse to a hierarchy of five levels and that problems in the two lowest levels SS{sub 0} and SS{sub 1} have a fully polynomial time randomized approximation scheme. We define extended classes MSF{sub n}, MPF{sub n} SSF{sub n}, and SPF{sub n} by allowing formulae to contain predicates definable in a logic known as least fixpoint logic. The resulting hierarchies classes collapse to the same number of levels and problems in the bottom levels can be approximated as before, but now some problems descend from the highest levels in the original hierarchies to the lowest levels in the new hierarchies. We introduce a method characterizing rates of growth of average solution sizes thereby showing a number of important problems do not belong MSF{sub 1} and SSF{sub 1}. This method is related to limit laws for logics and the probabilistic method from combinatorics.

Compton, K. [Univ. of Michigan, Ann Arbor, MI (United States)

1994-12-31

91

A Longitudinal Analysis of Gender Differences in Academic Self-Concept and Language Achievement: A Multivariate Multilevel Latent Growth Approach  

ERIC Educational Resources Information Center

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…

De Fraine, Bieke; Van Damme, Jan; Onghena, Patrick

2007-01-01

92

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

ERIC Educational Resources Information Center

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;…

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

2013-01-01

93

Estimating Correlates of Growth between Mathematics and Science Achievement via a Multivariate Multilevel Design with Latent Variables  

ERIC Educational Resources Information Center

The purpose of the present study was to improve a multivariate multilevel model in the research literature which estimates the consistency in the rates of growth between mathematics and science achievement among students and schools. We introduced a new multivariate multilevel model via a latent variable approach. Data from the Longitudinal Study…

Ma, Lingling; Ma, Xin

2005-01-01

94

Optimizing the Immune System to Achieve Control of the Metastatic Malignant Lesion  

PubMed Central

In a recent issue of Nature, an article appeared discussing the issue of “Sizing up a slow assault on Cancer” (Nature 2013;496:14-15). This article attempted to clarify various approaches that the clinician might employ in bringing cancer under control. It also discussed the role of the immune system with regard to its capability for controlling tumor growth. In addition, it covered possible directions that might be taken to improve present responses to immunotherapy based on utilizing T-cell activity directed against the tumor. While there is some validity to the concept that cell mediated immunity is utilized by the host in its attempt to control evolving malignancy, this process actually represents only a minor role taken by the hosts immune system to accomplish what is needed for tumor control. Clinical studies at Precision Biologics have demonstrated that for tumor growth to be effected properly by the hosts immune system, expression of a specific humoral IgG1 response directed against immunogenic tumor glycoproteins on the cell surface membrane, constitutes the primary method needed for tumor control. Failure to obtain significant levels of the needed IgG response almost invariably results in recurrence and progression of disease. PMID:23833687

Arlen, Myron; Arlen, Philip

2013-01-01

95

The barriers to using urban infill development to achieve smart growth  

Microsoft Academic Search

The smart growth movement of the 1990s has seen many development and planning associations, state and local governments, and the Clinton administration encourage significant infill development to control sprawl and promote revitalization. Will the 123 million projected increase in population in the next 50 years be attracted to infill development or to outlying growth areas?A review of 22 major central

J. Terrence Farris

2001-01-01

96

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

E-print Network

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 ...

Yang, Yung-Hun

97

Using Above-Level Testing to Track Growth in Academic Achievement in Gifted Students  

ERIC Educational Resources Information Center

Above-level testing is the practice of administering aptitude or academic achievement tests that are designed for typical students in higher grades or older age-groups to gifted or high-achieving students. Although widely accepted in gifted education, above-level testing has not been subject to careful psychometric scrutiny. In this study, I…

Warne, Russell T.

2014-01-01

98

Unbounded entanglement can be needed to achieve the optimal success probability  

E-print Network

Quantum entanglement is known to provide a strong advantage in many two-party distributed tasks. We investigate the question of how much entanglement is needed to reach optimal performance. For the first time we show that there exists a purely classical scenario for which no finite amount of entanglement suffices. To this end we introduce a simple two-party nonlocal game $H$, inspired by Lucien Hardy's paradox. In our game each player has only two possible questions and can provide bit strings of any finite length as answer. We exhibit a sequence of strategies which use entangled states in increasing dimension $d$ and succeed with probability $1-O(d^{-c})$ for some $c\\geq 0.13$. On the other hand, we show that any strategy using an entangled state of local dimension $d$ has success probability at most $1-\\Omega(d^{-2})$. In addition, we show that any strategy restricted to producing answers in a set of cardinality at most $d$ has success probability at most $1-\\Omega(d^{-2})$. Finally, we generalize our construction to derive similar results starting from any game $G$ with two questions per player and finite answers sets in which quantum strategies have an advantage.

Laura Man?inska; Thomas Vidick

2014-02-17

99

Mapped weighted essentially non-oscillatory schemes: Achieving optimal order near critical points  

NASA Astrophysics Data System (ADS)

In this paper, a new fifth-order weighted essentially non-oscillatory scheme is developed. Necessary and sufficient conditions on the weights for fifth-order convergence are derived; one more condition than previously published is found. A detailed analysis reveals that the version of this scheme implemented by Jiang and Shu [G.-S. Jiang, C.-W. Shu, Efficient implementation of weighted ENO schemes, J. Comput. Phys. 126 (1996) 202-228] is, in general, only third-order accurate at critical points. This result is verified in a simple example. The magnitude of ?, a parameter which keeps the weights bounded, and the level of grid resolution are shown to determine the order of the scheme in a non-trivial way. A simple modification of the original scheme is found to be sufficient to give optimal order convergence even near critical points. This is demonstrated using the one-dimensional linear advection equation. Also, four examples utilizing the compressible Euler equations are used to demonstrate the scheme's improved behavior for practical shock capturing problems.

Henrick, Andrew K.; Aslam, Tariq D.; Powers, Joseph M.

2005-08-01

100

Optimization of estrogen growth response in MCF7 cells  

Microsoft Academic Search

Summary  The factors involved in estradiol-17? induced growth stimulation of MCF-7 human breast cancer cells have been examined. Wild\\u000a type MCF-7 cells (and clone E3) were shown to undergo slow growth in phenol-red-free medium containing specific calf sera.\\u000a The E3 clone was used to document a mean 6-day growth stimulation of 3.35-fold (doubling time=33±3 h) in cultures supplemented\\u000a with 10?11\\u000a M

Thomas E. Wiese; Leos G. Kral; Kathleen E. Dennis; W. Barkley Butler; S. C. Brooks

1992-01-01

101

Feature selection by higher criticism thresholding achieves the optimal phase diagram.  

PubMed

We consider two-class linear classification in a high-dimensional, small-sample-size setting. Only a small fraction of the features are useful, these being unknown to us, and each useful feature contributes weakly to the classification decision. This was called the rare/weak (RW) model in our previous study (Donoho, D. & Jin, J. 2008 Proc. Natl Acad. Sci. USA 105, 14 790-14 795). We select features by thresholding feature Z-scores. The threshold is set by higher criticism (HC). For 1optimizes the classification error. In that previous study, we showed that HCT was numerically close to the ideal threshold. We formalize an asymptotic framework for studying the RW model, considering a sequence of problems with increasingly many features and relatively fewer observations. We show that, along this sequence, the limiting performance of ideal HCT is essentially just as good as the limiting performance of ideal thresholding. Our results describe two-dimensional phase space, a two-dimensional diagram with coordinates quantifying 'rare' and 'weak' in the RW model. The phase space can be partitioned into two regions-one where ideal threshold classification is successful, and one where the features are so weak and so rare that it must fail. Surprisingly, the regions where ideal HCT succeeds and fails make exactly the same partition of the phase diagram. Other threshold methods, such as false (feature) discovery rate (FDR) threshold selection, are successful in a substantially smaller region of the phase space than either HCT or ideal thresholding. The FDR and local FDR of the ideal and HC threshold selectors have surprising phase diagrams, which are also described. Results showing the asymptotic equivalence of HCT with ideal HCT can be found in a forthcoming paper (Donoho, D. & Jin, J. In preparation). PMID:19805453

Donoho, David; Jin, Jiashun

2009-11-13

102

Optimization of culture medium for growth of Haematococcus pluvialis  

Microsoft Academic Search

A central composite rotatable design was used to examine the effects of five components of the medium on the growth of Haematococcus\\u000a pluvialis in batch culture. The medium components considered were: sodium acetate,potassium nitrate, major elements, trace\\u000a elements and vitamins. Within the range of the concentrations tested, a moderate concentration of the major elements significantly\\u000a enhanced algal growth, both in

Xiandi Gong; Feng Chen

1997-01-01

103

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

ERIC Educational Resources Information Center

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…

Beecher, Constance C.

2011-01-01

104

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...

105

Assessing the Contribution of Distributed Leadership to School Improvement and Growth in Math Achievement  

ERIC Educational Resources Information Center

Although there has been sizable growth in the number of empirical studies of shared forms of leadership over the past decade, the bulk of this research has been descriptive. Relatively few published studies have investigated the impact of shared leadership on school improvement. This longitudinal study examines the effects of distributed…

Heck, Ronald H.; Hallinger, Philip

2009-01-01

106

A General Multivariate Latent Growth Model with Applications to Student Achievement  

ERIC Educational Resources Information Center

The evaluation of the formative process in the University system has been assuming an ever increasing importance in the European countries. Within this context, the analysis of student performance and capabilities plays a fundamental role. In this work, the authors propose a multivariate latent growth model for studying the performances of a…

Bianconcini, Silvia; Cagnone, Silvia

2012-01-01

107

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

108

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

ERIC Educational Resources Information Center

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…

Mackinnon, Sean P.

2012-01-01

109

Intrauterine-like growth rates can be achieved with premixed parenteral nutrition solution in preterm infants.  

PubMed

Growth failure in neonatal intensive care units is a major challenge for pediatricians and neonatologists. The use of early "aggressive" parenteral nutrition (PN), with >2.5 g/(kg ·d) of amino acids and at least 40 kcal/(kg ·d) of energy from the first day of life, has been shown to provide nutritional intakes in the range recommended by international guidelines, reducing nutritional deficit and the incidence of postnatal growth restriction in preterm infants. However, nutritional practices and adherence to recommendations may vary in different hospitals. Two ready-to-use (RTU), premixed parenteral solutions (PSs) designed for preterm infants have been prospectively evaluated: a binary RTU premixed PS from our hospital pharmacy and a commercially premixed 3-chamber bag (Baxter Healthcare). These premixed PSs provide nitrogen and energy intakes in the range of the most recent recommendations, reducing or eliminating the early cumulative nutritional deficit in very-low-birth-weight infants, and avoiding the development of postnatal growth restriction. A further rationale for RTU premixed PSs is that preterm infants require balanced PN that contains not only amino acids and energy but also minerals and electrolytes from the first day of life in order to reduce the incidence of metabolic disorders frequently reported in extremely-low-birth-weight infants during the early weeks of life. PMID:24108133

Rigo, Jacques; Senterre, Thibault

2013-12-01

110

Optimizing growth hormone replacement therapy by dose titration in hypopituitary adults.  

PubMed

Although growth hormone (GH) replacement therapy is increasingly 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 individual variation in susceptibility on the basis of gender and other factors is now being recognized. To optimize GH replacement and to explore further gender differences in susceptibility, we used a dose titration regimen, starting at the initiation of GH replacement therapy, in 50 consecutive adult-onset hypopituitary patients, and compared the results with those in 21 patients previously treated using a weight-based regimen. Titrated patients commenced GH 0.8 IU/day subcutaneously (0.4 IU/day if hypertensive or glucose tolerance impaired). Serum insulin-like growth factor I (IGF-I) was measured at 0, 2, 4, 6, 8, 10, and 12 weeks in all patients. Serum IGF binding protein 3 and acid labile subunit were measured at the same time points in 17 patients (8 male, 9 female). Patients were reviewed every 4 weeks and the dose of GH increased, if necessary, to achieve a serum IGF-I level between the median and the upper end of the age-related reference range. There was no significant difference between mean serum IGF-I at 2 and 4 weeks, or between 6 and 8 weeks, indicating that the full effects of a change in dose are evident within 2 weeks of that change. Maintenance doses were significantly higher in females than males [1.2 (0.8-2.0) vs. 0.8 (0.4-1.6) IU/day; median (range); P < 0.0001], and the median time to achieve maintenance dose was significantly shorter in males [4 (2-12) vs. 9 (2-26) weeks; P < 0.0001]. Median maintenance dose was lower overall than in a group of 21 patients initially commenced on GH using a weight-based dosing schedule, with subsequent adjustment of dose during clinical follow-up [1.5 (0.4-3.2) IU/day; P = 0.02]. Reduction in waist measurement and waist to hip ratio at 6 and 12 months was similar in females (P < 0.001) and males (P < 0.01). Well-being improved significantly after 3 months of GH therapy (14.2 +/- 5.9 vs. 7.4 +/- 4.5 SD; P < 0.0001), and there were no gender differences. Adult Growth Hormone Deficiency Assessment (AGHDA) scores at 6 months were similar to maintenance scores in patients commenced on weight-based regimens. Measurements of ALS and IGFBP-3 added no useful extra information to IGF-I in managing the dose titration. The practical scheme outlined for dose titration of GH replacement resulted in rapid achievement of lower maintenance doses than those achieved using conventional weight-based regimens without loss of efficacy. It was particularly important in female patients who demonstrated decreased overall sensitivity to GH and required higher doses to achieve the same effects as males. This constitutes the first report of a uniform titration regimen based on a defined target range of serum IGF-I in a large patient cohort. PMID:9814468

Drake, W M; Coyte, D; Camacho-Hübner, C; Jivanji, N M; Kaltsas, G; Wood, D F; Trainer, P J; Grossman, A B; Besser, G M; Monson, J P

1998-11-01

111

Optimization of crystal growth by changes of flow guide, radiation shield and sidewall insulation in Cz Si furnace  

Microsoft Academic Search

In solar-grade single crystal silicon Cz growth, the geometries of argon flow guide, heat shields and insulations are main parameters affecting the heat exchange and crystal growth conditions. By changing the above parameters, an optimization of crystal growth was attempted. Numerical simulations before and after optimization were provided to verify the results. Through analyses of the temperature distribution in the

Wenjia Su; Ran Zuo; Kirill Mazaev; Vladimir Kalaev

2010-01-01

112

Studying the Relationship between Children's Self-Control and Academic Achievement: An Application of Second-Order Growth Curve Model Analysis.  

ERIC Educational Resources Information Center

The functional relationships between developmental change in children's self-control and academic achievement were examined using longitudinal family data. Multivariate latent growth models (LGM) were specified to determine whether the rate of growth in academic achievement changes as a function of developmental change in self-control. Data came…

Kim, Sooyeon; Murry, Velma McBride; Brody, Gene H.

113

Study on growth optimization and metallization of AlN thin films  

NASA Astrophysics Data System (ADS)

Aluminum nitride (AlN) thin films were prepared by reactive magnetron sputtering on silicon substrate with AlN nano seed crystals in argon and nitrogen gas mixtures. The influences of the deposition parameters (pressure, ratio of argon to nitrogen, sputtering power) on the transmittance and structure of the AlN thin films were investigated. X-ray diffraction (XRD) analysis showed a preferred orientation of the AlN (100). The results also showed the optimal condition for AlN growth, i.e. 0.6 Pa for working pressure, 4:1 for nitrogen/argon ratio and 300W for sputtering power. Since copper could not be adhesive to AlN for heat-sink applications, titanium layer was inserted between AlN and copper as a transition layer to achieve the metallization of AlN. We found that the films with titanium layer had obviously better adhesion property, as compared with the films without titanium layer.

Liu, Zhen; Zhang, Bin; Zhu, Tao; Chen, Yigang

2013-12-01

114

Achieving growth and excellence in medicine: the case history of armed conflict and modern reconstructive surgery.  

PubMed

November 11, 2009 will mark over 90 years of commemorating Armistice Day, the end of World War I. Although conflict in the Middle East reminds us that WWI failed to end all wars, it did serve as both substrate and catalyst for the development of modern plastic and reconstructive surgery. This article will outline those ingredients most directly responsible for the growth of the specialty, tracing its development in response to armed conflict, and implications for continued excellence both in reconstructive surgery and other fields in the future. PMID:20431512

Chambers, James Alan; Ray, Peter Damian

2009-11-01

115

Patterned growth of carbon nanotubes over vertically aligned silicon nanowire bundles for achieving uniform field emission  

PubMed Central

A fabrication strategy is proposed to enable precise coverage of as-grown carbon nanotube (CNT) mats atop vertically aligned silicon nanowire (VA-SiNW) bundles in order to realize a uniform bundle array of CNT-SiNW heterojunctions over a large sample area. No obvious electrical degradation of as-fabricated SiNWs is observed according to the measured current-voltage characteristic of a two-terminal single-nanowire device. Bundle arrangement of CNT-SiNW heterojunctions is optimized to relax the electrostatic screening effect and to maximize the field enhancement factor. As a result, superior field emission performance and relatively stable emission current over 12 h is obtained. A bright and uniform fluorescent radiation is observed from CNT-SiNW-based field emitters regardless of its bundle periodicity, verifying the existence of high-density and efficient field emitters on the proposed CNT-SiNW bundle arrays. PMID:25298758

2014-01-01

116

Growth parameter optimization of the GaInP/AlGaInP active zone of 635 nm red laser diodes  

NASA Astrophysics Data System (ADS)

GaAs-based laser diodes emitting in the red spectral region have challenging material and thermal properties when reducing the emission wavelength towards the physical limit around 630 nm. To improve the properties of such laser diodes, we have optimized the growth parameters of the GaInP quantum wells (QW) embedded in AlGaInP. The growth temperature and the V/III ratio during growth of the QW was varied. By reducing the QW growth temperature from 770 to 700 °C, an improvement of the laser performance was achieved at 635 and at 643 nm laser emission wavelength. By increasing the V/III ratio, a higher photoluminescence intensity could be achieved in QW test samples. Combining both approaches important laser parameters like threshold current density, differential efficiency and internal absorption were improved substantially.

Kaspari, Christian; Zorn, Martin; Weyers, Markus; Erbert, Götz

2008-11-01

117

Optimization of high purity germanium (HPGe) crystals growth rate through the simulation and modeling of growth system geometry  

NASA Astrophysics Data System (ADS)

The growth rate and quality of high-purity germanium (HPGe) single crystals depend largely on the control of the thermal field such as the temperature profile and heat transfer. The control parameters of the thermal field can only be regulated externally through the growth system geometry, hydrogen and argon gas pressure, flow rate, pulling rate, and power and frequency of a RF heater. Since quantitative determination of the control parameters is exceptionally challenging and expensive, computer modeling and simulation of CZ growth processes play an imperative role in the advances of innovative pulling procedures and augmentation of Ge crystal quality. We present a detailed modeling and simulation study of radial and vertical temperature gradient, radial and vertical heat flux, temperature profile, thermo-elastic stresses, and defect density analysis for different crystal positions and diverse growth system geometry. We also virtually studied the consequences of targeted growth rate on temperature gradient and induction heating. A comparative analysis of simulated and available experimental results is also presented. In this effort, we have demonstrated the importance of simulation and modeling as it helps reducing the number of growth experiments significantly for the optimization of crystal quality and targeted growth rate.

Govani, Jayesh; Mei, Dongming; Wang, Guojian; Yang, Gang

2012-02-01

118

Optimization of VGF-growth of GaAs crystals by the aid of numerical modelling  

NASA Astrophysics Data System (ADS)

The VGF growth of Si-doped GaAs crystals is improved considerably by optimizing the design of the crucible support and the temperature profile during the growth run. Inverse simulation with the software program CrysVUN++ was used for this procedure. The criteria for the optimized conditions are flat phase boundaries and low thermal stress during the whole growth run. The crystals which were grown according to the simulated conditions indeed showed flat phase boundaries and a very low EPD (<100 cm -2) within the whole crystal. It is shown that the growth conditions in the seed well and conical part of the crystal have a major influence on the dislocation density in the whole crystal.

Müller, G.; Birkmann, B.

2002-04-01

119

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

Microsoft Academic Search

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

Lucy Bostock; Alia I. Sheikh; Stephen Barton

2009-01-01

120

Tumor Growth Rate Determines the Timing of Optimal Chronomodulated Treatment Schedules  

E-print Network

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

Paris-Sud XI, Université de

121

Human primary brain tumor cell growth inhibition in serum-free medium optimized for neuron survival  

Microsoft Academic Search

Glioblastoma is the most common primary brain tumor in adults from which about 15,000 patients die each year in the United States. Despite aggressive surgery, radiotherapy and chemotherapy, median survival remains only 1 year. Here we evaluate growth of primary human brain tumor cells in a defined nutrient culture medium (Neuregen) that was optimized for neuron regeneration. We hypothesized that

Gregory J. Brewer; Peter D. LeRoux

2007-01-01

122

Toward Optimized Light Utilization in Nanowire Arrays Using Scalable Nanosphere Lithography and Selected Area Growth  

E-print Network

, in which achieving scalable synthesis and optimized optical absorption simultaneously is critical. Here, we, thus minimizing the lattice-matching constraints in heteroepitaxy as compared to conventional thin film (SA-MOCVD) for the first time for scalable synthesis of vertically aligned gallium arsenide nanowire

Zhou, Chongwu

123

Understanding precision nitrogen stress to optimize the growth and lipid content tradeoff in oleaginous green microalgae.  

PubMed

Nitrogen deficiency promotes lipid formation in many microalgae, but also limits growth and lipid productivity. In spite of numerous studies, there is poor understanding of the interactions of growth and lipid content, the time course of lipid accumulation and the magnitude of nitrogen deficiency required to stimulate lipid formation. These relationships were investigated in six species of oleaginous green algae, comparing high and low levels of deficiency. Nitrogen stress typically had disproportionate effects on growth and lipid content, with profound differences among species. Optimally balancing the tradeoffs required a wide range in nitrogen supply rate among species. Some species grew first and then accumulated lipids, while other species grew and accumulated lipids concurrently which resulted in increased lipid productivity. Accumulation of high lipid content generally resulted from a response to minimal stress. The data highlight the tremendous biodiversity that may be exploited to optimally produce lipids with precision nitrogen stress. PMID:23347926

Adams, Curtis; Godfrey, Valerie; Wahlen, Brad; Seefeldt, Lance; Bugbee, Bruce

2013-03-01

124

Optimizing Bi2O3 and TiO2 to achieve the maximum non-linear electrical property of ZnO low voltage varistor  

PubMed Central

Background In fabrication of ZnO-based low voltage varistor, Bi2O3 and TiO2 have been used as former and grain growth enhancer factors respectively. Therefore, the molar ratio of the factors is quit important in the fabrication. In this paper, modeling and optimization of Bi2O3 and TiO2 was carried out by response surface methodology to achieve maximized electrical properties. The fabrication was planned by central composite design using two variables and one response. To obtain actual responses, the design was performed in laboratory by the conventional methods of ceramics fabrication. The actual responses were fitted into a valid second order algebraic polynomial equation. Then the quadratic model was suggested by response surface methodology. The model was validated by analysis of variance which provided several evidences such as high F-value (153.6), very low P-value (<0.0001), adjusted R-squared (0.985) and predicted R-squared (0.947). Moreover, the lack of fit was not significant which means the model was significant. Results The model tracked the optimum of the additives in the design by using three dimension surface plots. In the optimum condition, the molars ratio of Bi2O3 and TiO2 were obtained in a surface area around 1.25 point that maximized the nonlinear coefficient around 20 point. Moreover, the model predicted the optimum amount of the additives in desirable condition. In this case, the condition included minimum standard error (0.35) and maximum nonlinearity (20.03), while molar ratio of Bi2O3 (1.24 mol%) and TiO2 (1.27 mol%) was in range. The condition as a solution was tested by further experiments for confirmation. As the experimental results showed, the obtained value of the non-linearity, 21.6, was quite close to the predicted model. Conclusion Response surface methodology has been successful for modeling and optimizing the additives such as Bi2O3 and TiO2 of ZnO-based low voltage varistor to achieve maximized non-linearity properties. PMID:23938168

2013-01-01

125

Optimal fetal growth for the Caucasian singleton and assessment of appropriateness of fetal growth: an analysis of a total population perinatal database  

Microsoft Academic Search

BACKGROUND: The appropriateness of an individual's intra uterine growth is now considered an important determinant of both short and long term outcomes, yet currently used measures have several shortcomings. This study demonstrates a method of assessing appropriateness of intrauterine growth based on the estimation of each individual's optimal newborn dimensions from routinely available perinatal data. Appropriateness of growth can then

Eve M Blair; Yingxin Liu; Nicholas H de Klerk; David M Lawrence

2005-01-01

126

Reducing the Academic Risks of Over-Optimism: The Longitudinal Effects of Attributional Retraining on Cognition and Achievement  

Microsoft Academic Search

Although optimism is generally regarded as a positive dispositional characteristic, unmitigated optimism can be problematic. The adaptiveness of overly optimistic expectations in novel or unfamiliar settings is questionable because individuals have little relevant experience on which to base such expectations. In this four-phase longitudinal study we examined over-optimism in students when making the transition from a familiar academic setting (high

Tara L. Haynes; Joelle C. Ruthig; Raymond P. Perry; Robert H. Stupnisky; Nathan C. Hall

2006-01-01

127

Optimization of hydrothermal growth ZnO Nanorods for enhancement of light extraction from GaN blue LEDs  

NASA Astrophysics Data System (ADS)

In this study, we report on the enhancement in the light extraction efficiency of GaN blue LEDs topped with ZnO nanorods. The ZnO nanorods were grown by a two-step hydrothermal synthesis with pre-coated ZnO nanoparticles under optimized condition to give the appropriate size and quality, giving an increase in the light output efficiency of 66%. This improvement is attributed to the optimal rod size and spacing with improved thermal dissipation as compared to light extraction from plain GaN surface. During the ZnO growth on the LEDs, 0.55 M of NH 3 was added and the ZnO sample was later annealed at 475 °C in N 2 ambient, to drive out interstitial oxygen atoms from the tetrahedral unstable site. As a result, a high ratio of UV to orange defect band emission was achieved. The two-step growth of ZnO nanorods on GaN LEDs was effective in generating array of ZnO nanorods which serve as reflector to enhance light extraction from LEDs.

Soh, C. B.; Tay, C. B.; Chua, S. J.; Le, H. Q.; Ang, N. S. S.; Teng, J. H.

2010-05-01

128

Optimization of ZnSe growth on miscut GaAs substrates by molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

We report growth optimization of molecular beam epitaxy (MBE) grown ZnSe on GaAs (0 0 1) substrate tilted by 15° toward [1 1 0] in terms of beam equivalent pressure (BEP) ratio and growth temperature. A LT-ZnSe buffer was grown to reduce the formation of Ga-Se bonding, a well-known source of defect generation, due to interdiffusion through the heterointerface in the initial stage of growth. The ZnSe layer was further optimized by low-temperature-grown (LT-ZnSe) buffer. The optical and structural properties of the ZnSe film with LT-ZnSe and GaAs buffer are also analyzed by photoluminescence spectroscopy (PL), X-ray diffraction (XRD), and secondary ion mass spectroscopy (SIMS), which show very large intensity ratio of near-band-edge emission to deep level emission, narrow XRD peak width of (0 0 4) rocking curves, and abrupt ZnSe/GaAs heterointerface under the optimum growth condition, respectively. The optimum growth conditions are BEP ratio ( PSe/ PZn) of 3 and growth temperature of 310°C with an LT-ZnSe buffer grown at 250°C.

Song, J. S.; Chang, J. H.; Oh, D. C.; Kim, J. J.; Cho, M. W.; Makino, H.; Hanada, T.; Yao, T.

2003-02-01

129

Optimal stoichiometry for nucleation and growth of conductive filaments in HfOx  

NASA Astrophysics Data System (ADS)

We present a first principles based investigation into the nucleation and growth of metal-rich precipitates in substoichiometric hafnium dioxide with relevance to applications in resistive switching memories. We identify an optimal HfOx stoichiometry, with x in the range 1.50-1.75, for efficient nucleation and growth of stable Hf-rich clusters which may serve as precursors for the growth of conductive filaments during forming. We also show that filaments with sub-nm diameter posses remarkably metallic character. These results provide invaluable atomistic insight into forming in resistive switching films and demonstrate that precise regulation of stoichiometry is essential in order to ensure uniformity in the nucleation and subsequent growth of a conductive filament during the forming process.

McKenna, K. P.

2014-03-01

130

Optimized clinical performance of growth hormone with an expanded genetic code  

PubMed Central

The ribosomal incorporation of nonnative amino acids into polypeptides in living cells provides the opportunity to endow therapeutic proteins with unique pharmacological properties. We report here the first clinical study of a biosynthetic protein produced using an expanded genetic code. Incorporation of p-acetylphenylalanine (pAcF) at distinct locations in human growth hormone (hGH) allowed site-specific conjugation with polyethylene glycol (PEG) to produce homogeneous hGH variants. A mono-PEGylated mutant hGH modified at residue 35 demonstrated favorable pharmacodynamic properties in GH-deficient rats. Clinical studies in GH-deficient adults demonstrated efficacy and safety comparable to native human growth hormone therapy but with increased potency and reduced injection frequency. This example illustrates the utility of nonnative amino acids to optimize protein therapeutics in an analogous fashion to the use of medicinal chemistry to optimize conventional natural products, low molecular weight drugs, and peptides. PMID:21576502

Cho, Ho; Daniel, Tom; Buechler, Ying Ji; Litzinger, David C.; Maio, Zhenwei; Putnam, Anna-Maria Hays; Kraynov, Vadim S.; Sim, Bee-Cheng; Bussell, Stuart; Javahishvili, Tsotne; Kaphle, Sami; Viramontes, Guillermo; Ong, Mike; Chu, Stephanie; GC, Becky; Lieu, Ricky; Knudsen, Nick; Castiglioni, Paola; Norman, Thea C.; Axelrod, Douglas W.; Hoffman, Andrew R.; Schultz, Peter G.; DiMarchi, Richard D.; Kimmel, Bruce E.

2011-01-01

131

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

SciTech Connect

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.

Lyashenko, O.I.

1995-12-10

132

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

133

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

Microsoft Academic Search

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

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

2006-01-01

134

YBCO\\/Ag composites through a preform optimized infiltration and growth process yield high current densities  

Microsoft Academic Search

Bulk YBa2Cu3O7 - delta (YBCO)\\/Ag composites with a homogeneous distribution of fine and spherical particles of metallic silver and Y2BaCuO5 (Y-211) have been fabricated using a preform optimized infiltration growth process (POIGP). The effect of two different methods of introducing silver, one directly into the Y-211 preform and the other into the liquid phase source placed above the Y-211 preform,

N. Devendra Kumar; T. Rajasekharan; V. Seshubai

2011-01-01

135

Optimization of vascular-targeting drugs in a computational model of tumor growth  

NASA Astrophysics Data System (ADS)

A biophysical tool is introduced that seeks to provide a theoretical basis for helping drug design teams assess the most promising drug targets and design optimal treatment strategies. The tool is grounded in a previously validated computational model of the feedback that occurs between a growing tumor and the evolving vasculature. In this paper, the model is particularly used to explore the therapeutic effectiveness of two drugs that target the tumor vasculature: angiogenesis inhibitors (AIs) and vascular disrupting agents (VDAs). Using sensitivity analyses, the impact of VDA dosing parameters is explored, as is the effects of administering a VDA with an AI. Further, a stochastic optimization scheme is utilized to identify an optimal dosing schedule for treatment with an AI and a chemotherapeutic. The treatment regimen identified can successfully halt simulated tumor growth, even after the cessation of therapy.

Gevertz, Jana

2012-04-01

136

Growth  

NASA Astrophysics Data System (ADS)

This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000?C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However, molecular beam epitaxy (MBE) delivers high quality ZnMgO-ZnO quantum well structures. Other thin film techniques such as PLD or MOCVD are also widely used. The main problem at present is to consistently achieve reliable p-type doping. For this topic, see also Chap. 5. In the past years, there have been numerous publications on p-type doping of ZnO, as well as ZnO p-n junctions and light emitting diodes (LEDs). However, a lot of these reports are in one way or the other inconsistent or at least incomplete. It is quite clear from optical data that once a reliable hole injection can be achieved, high brightness ZnO LEDs should be possible. In contrast to that expectation, none of the LEDs reported so far shows efficient light emission, as would be expected from a reasonable quality ZnO-based LED. See also Chap. 13. As a matter of fact, there seems to be no generally accepted and reliable technique for p-type doping available at present. The reason for this is the unfavorable position of the band structure of ZnO relative to the vacuum level, with a very low lying valence band. See also Fig. 5.1. This makes the incorporation of electrically active acceptors difficult. Another difficulty is the huge defect density in ZnO. There are many indications that defects play a major role in transport and doping. In order to solve the doping problem, it is generally accepted that the quality of the ZnO material grown by the various techniques needs to be improved. Therefore, the optimization of ZnO epitaxy is thought to play a key role in the further development of this material system. Besides being used as an active material in optoelectronic devices, ZnO plays a major role as transparent contact material in thin film solar cells. Polycrystalline, heavily n-type doped ZnO is used for this, combining a high electrical conductivity with a good optical transparency. In this case, ZnO thin films are fabricated by large area growth techniques such as sputtering. For this and other applications, see also Chap. 13.

Waag, Andreas

137

Omic data from evolved E. coli are consistent with computed optimal growth from genome-scale models  

SciTech Connect

After hundreds of generations of mid log phase growth, Escherichia coli acquires a higher growth rate as predicted using flux balance analysis (FBA) on genome-scale metabolic models (GEMs). FBA solutions contain hundreds of variables that can be examined using omics methods. We report that 99% of active reactions from FBA optimal growth solutions are supported by transcriptomic and proteomic data. Moreover, when E. coli adapts to growth rate selective pressure, the resulting evolved strains reinforce the optimal growth predictions. Specifically, through constraint-based analysis of the proteomic and transcriptomic data, we find: 1) selective pressure for the predicted optimal growth states and a minimization of network flux; 2) suppression of genes outside of the optimal growth solutions; and 3) a trend towards usage of more efficient metabolic pathways. For processes not in GEMs, we find 4) an increase in the transcription/translation machinery and stringent response suppression, and 5) that established regulons are significantly down-regulated. Thus, differential expression supports observed growth phenotype changes, and observed expression in evolved strains is consistent with GEM computed optimal growth states.

Lewis, Nathan E.; Hixson, Kim K.; Conrad, Tom M.; Lerman, Joshua A.; Charusanti, Pep; Polpitiya, Ashoka D.; Adkins, Joshua N.; Schramm, Gunnar; Purvine, Samuel O.; Lopez-Ferrer, Daniel; Weitz, Karl K.; Eils, Roland; Konig, Rainer; Smith, Richard D.; Palsson, Bernhard O.

2010-07-27

138

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

E-print Network

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, ...

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

2009-01-01

139

Regeneration of viable oil palm plants from protoplasts by optimizing media components, growth regulators and cultivation procedures.  

PubMed

Oil palm protoplasts are suitable as a starting material for the production of oil palm plants with new traits using approaches such as somatic hybridization, but attempts to regenerate viable plants from protoplasts have failed thus far. Here we demonstrate, for the first time, the regeneration of viable plants from protoplasts isolated from cell suspension cultures. We achieved a protoplast yield of 1.14×10(6) per gram fresh weight with a viability of 82% by incubating the callus in a digestion solution comprising 2% cellulase, 1% pectinase, 0.5% cellulase onuzuka R10, 0.1% pectolyase Y23, 3% KCl, 0.5% CaCl2 and 3.6% mannitol. The regeneration of protoplasts into viable plants required media optimization, the inclusion of plant growth regulators and the correct culture technique. Microcalli derived from protoplasts were obtained by establishing agarose bead cultures using Y3A medium supplemented with 10?M naphthalene acetic acid, 2?M 2,4-dichlorophenoxyacetic acid, 2?M indole-3-butyric acid, 2?M gibberellic acid and 2?M 2-?-dimethylallylaminopurine. Small plantlets were regenerated from microcalli by somatic embryogenesis after successive subculturing steps in medium with limiting amounts of growth regulators supplemented with 200mg/l ascorbic acid. PMID:23849119

Masani, Mat Yunus Abdul; Noll, Gundula; Parveez, Ghulam Kadir Ahmad; Sambanthamurthi, Ravigadevi; Prüfer, Dirk

2013-09-01

140

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

Microsoft Academic Search

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.)

Kenneth S. Hebel; Reena C. Gajjar

1997-01-01

141

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

ERIC Educational Resources Information Center

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…

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

142

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

143

Optimal photosynthetic use of light by tropical tree crowns achieved by adjustment of individual leaf angles and nitrogen content  

PubMed Central

Background and Aims Theory for optimal allocation of foliar nitrogen (ONA) predicts that both nitrogen concentration and photosynthetic capacity will scale linearly with gradients of insolation within plant canopies. ONA is expected to allow plants to efficiently use both light and nitrogen. However, empirical data generally do not exhibit perfect ONA, and light-use optimization per se is little explored. The aim was to examine to what degree partitioning of nitrogen or light is optimized in the crowns of three tropical canopy tree species. Methods Instantaneous photosynthetic photon flux density (PPFD) incident on the adaxial surface of individual leaves was measured along vertical PPFD gradients in tree canopies at a frequency of 0·5 Hz over 9–17 d, and summed to obtain the average daily integral of PPFD for each leaf to characterize its insolation regime. Also measured were leaf N per area (Narea), leaf mass per area (LMA), the cosine of leaf inclination and the parameters of the photosynthetic light response curve [photosynthetic capacity (Amax), dark respiration (Rd), apparent quantum yield (?) and curvature (?)]. The instantaneous PPFD measurements and light response curves were used to estimate leaf daily photosynthesis (Adaily) for each leaf. Key Results Leaf Narea and Amax changed as a hyperbolic asymptotic function of the PPFD regime, not the linear relationship predicted by ONA. Despite this suboptimal nitrogen partitioning among leaves, Adaily did increase linearly with PPFD regime through co-ordinated adjustments in both leaf angle and physiology along canopy gradients in insolation, exhibiting a strong convergence among the three species. Conclusions The results suggest that canopy tree leaves in this tropical forest optimize photosynthetic use of PPFD rather than N per se. Tropical tree canopies then can be considered simple ‘big-leaves’ in which all constituent ‘small leaves’ use PPFD with the same photosynthetic efficiency. PMID:19151040

Posada, Juan M.; Lechowicz, Martin J.; Kitajima, Kaoru

2009-01-01

144

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

ERIC Educational Resources Information Center

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…

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

2014-01-01

145

Optimization of speed control algorithm to achieve minimum torque ripple for a switched reluctance motor drive via GA  

Microsoft Academic Search

This study presents a speed controller design for a switched reluctance (SR) motor in order to achieve minimum torque ripple and high control performance. First of all, SR motor convertor designed for soft chopping is chosen. This converter as well as producing less torque ripple, provides more degrees of freedom for SR motor drive controller. A PID controller and a

Hanif Tahersima; Mohammadjafar Kazemsaleh; Mohammadhossein Tahersima; Navid Hamedi

2011-01-01

146

Monoraphidium sp. as an algal feedstock for biodiesel: Determining optimal growth conditions in wastewater  

NASA Astrophysics Data System (ADS)

This thesis set out to investigate different conditions for growth of the freshwater algal species Monoraphidium sp. for use as a feedstock for biodiesel. The algae was inoculated into effluent gathered from a local water treatment plant and placed into 50gal mesocosms. Cells were grown at large scale in wastewater, harvested, and run through extractions to collect lipids (26%DW). The lipids were then turned into biodiesel. The algae also removed most of the pollutants in the wastewater, lowering nitrate and phosphate levels usually to less than 1mg/L. Erlenmeyer flask cultures (1L) were used to determine optimal growth conditions for temperature (10°C), light intensity (30microE/m2/sec with a 10 hour photoperiod), and initial inoculation density (1x104cells/mL). The addition of bicarbonate during the initial or exponential growth phase had no effect on growth. It was concluded that Monoraphidium sp. grown in USDA Hardiness Zone 5 is capable of producing biodiesel.

Davidson, Zachary William

147

The Effects of a Growth Mindset Intervention on the Beliefs about Intelligence, Effort Beliefs, Achievement Goal Orientations, and Academic Self-Efficacy of LD Students with Reading Difficulties  

ERIC Educational Resources Information Center

The overall purpose of this study was to examine the effects of a "growth mindset" intervention on the beliefs about intelligence, effort beliefs, achievement goals, and academic self-efficacy of learning disabled (LD) students with reading difficulties. The treatment group consisted of 12 high school LD students with reading difficulties. This…

Baldridge, Mary Caufield

2010-01-01

148

Higher order scrambled digital nets achieve the optimal rate of the root mean square error for smooth integrands  

Microsoft Academic Search

We study numerical approximations of integrals $\\\\int_{[0,1]^s} f(\\\\boldsymbol{x}) \\\\,\\\\mathrm{d} \\\\boldsymbol{x}$ by averaging the function at some sampling points. Monte Carlo (MC) sampling yields a convergence of the root mean square error (RMSE) of order $N^{-1\\/2}$ (where $N$ is the number of samples). Quasi-Monte Carlo (QMC) sampling on the other hand achieves a convergence of order $N^{-1+\\\\varepsilon}$, for any $\\\\varepsilon >0$.

Josef Dick

2010-01-01

149

Construction and Optimization of Mevalonate Pathway for Production of Isoprenoids in Escherichia coli  

E-print Network

Escherichia coli evolve to computationally predicted growthF.G. , B. Growth-rate recovery of Escherichia coli culturesEscherichia coli K-12 undergoes adaptive evolution to achieve in silico predicted optimal growth.

Nowroozi, Farnaz F.B.

2010-01-01

150

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

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

151

Optimal control oriented to therapy for a free-boundary tumor growth model.  

PubMed

This paper is devoted to present and solve some optimal control problems, oriented to therapy, for a particular model of tumor growth. In the considered systems, the state is given by one or several functions that provide information on the cell population and also the tumor shape evolution and the control is a time dependent function associated to the therapy strategy (in practice, a cytotoxic drug). We first present and analyze the model (based on PDEs) and the related optimal control problems. The solutions are expected to provide the best therapy strategies for a given set of constraints (here, the cost or objective function is a measure of the number of cells at a given final time T). We also recall some mathematical techniques for solving the related optimization problems and we illustrate the behavior of the methods and the validity of the models with several numerical experiments. In view of the results, we are able to design appropriate strategies that, at least to some extent, are confirmed by real data. Finally, we present some conclusions and indications on future work. PMID:23485361

Calzada, M Carmen; Fernández-Cara, Enrique; Marín, Mercedes

2013-05-21

152

Optimal growth of Ge-rich dots on Si(001) substrates with hexagonal packed pit patterns.  

PubMed

This paper reports a three-step method to fabricate hexagonal ordered Ge dots on Si with controllable size and spacing. After the introduction of a thin Si dioxide layer on the Si substrate, porous alumina turns out to be a good candidate for pattern transferring, which is rapid and simple to implement. A density-temperature relation for Ge dots has been discovered in this work; the Arrhenius relation with a slope of 0.33 is proved to be applicable for predicting the optimal temperature for a certain density of patterns. Different widths of pits are also studied to discover the dependence of the dot distribution on the pit morphology. The optimal pit width for ordered Ge dots is around 30 nm, while four aligned Ge dots can be achieved in a 70 nm pit. Extremely high Ge content (>0.92) in capped Ge dots is discovered by Raman characterization because the high density of pits leads to a low enough optimal temperature of 430 °C. The photoluminescence spectra of the capped dots also prove the high purity and quality of the Ge dots. PMID:23263343

Huangfu, Yourui; Zhan, Wenbo; Hong, Xia; Fang, Xu; Ding, Guqiao; Ye, Hui

2013-01-25

153

An axenic plant culture system for optimal growth in long-term studies.  

PubMed

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. CDII) 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 a 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 microg d(-1). Fumaric, malic, malonic, oxalic, and succinic acids were measured as components of the root exudates. PMID:16510704

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

2006-01-01

154

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

155

Optimization of Energy-Consuming Pathways towards Rapid Growth in HPV-Transformed Cells  

PubMed Central

Cancer is a complex, multi-step process characterized by misregulated signal transduction and altered metabolism. Cancer cells divide faster than normal cells and their growth rates have been reported to correlate with increased metabolic flux during cell transformation. Here we report on progressive changes in essential elements of the biochemical network, in an in vitro model of transformation, consisting of primary human keratinocytes, human keratinocytes immortalized by human papillomavirus 16 (HPV16) and passaged repeatedly in vitro, and the extensively-passaged cells subsequently treated with the carcinogen benzo[a]pyrene. We monitored changes in cell growth, cell size and energy metabolism. The more transformed cells were smaller and divided faster, but the cellular energy flux was unchanged. During cell transformation the protein synthesis network contracted, as shown by the reduction in key cap-dependent translation factors. Moreover, there was a progressive shift towards internal ribosome entry site (IRES)-dependent translation. The switch from cap to IRES-dependent translation correlated with progressive activation of c-Src, an activator of AMP-activated protein kinase (AMPK), which controls energy-consuming processes, including protein translation. As cellular protein synthesis is a major energy-consuming process, we propose that the reduction in cell size and protein amount provide energy required for cell survival and proliferation. The cap to IRES-dependent switch seems to be part of a gradual optimization of energy-consuming mechanisms that redirects cellular processes to enhance cell growth, in the course of transformation. PMID:17622357

Ben-Bassat, Hannah; Klein, Shoshana; Levitzki, Alexander

2007-01-01

156

Optimization of crystal growth by changes of flow guide, radiation shield and sidewall insulation in Cz Si furnace  

NASA Astrophysics Data System (ADS)

In solar-grade single crystal silicon Cz growth, the geometries of argon flow guide, heat shields and insulations are main parameters affecting the heat exchange and crystal growth conditions. By changing the above parameters, an optimization of crystal growth was attempted. Numerical simulations before and after optimization were provided to verify the results. Through analyses of the temperature distribution in the crystal and melt, the argon gas flow between the radiation shield and the quartz crucible, and the thermal stresses in the crystal, it was found that the optimized heat shield can reduce the baking of crystal by the heater; the optimized side insulation can prevent the heat loss upward, and the optimized flow guide can decrease the SiO deposition on the upper wall. After optimization, under the same heater power, the crystallization rate is increased over 35%, without increase in macro-dislocation probability; the optimized V/G ratios along crystal radius are greater than the critical value, thus the probability of occurrence of OSF-ring in the crystal is also reduced.

Su, Wenjia; Zuo, Ran; Mazaev, Kirill; Kalaev, Vladimir

2010-02-01

157

Screening and optimization of indole-3-acetic acid production and phosphate solubilization from rhizobacteria aimed at improving plant growth.  

PubMed

A total of 216 bacterial strains were isolated from rice rhizospheric soils in Northern Thailand. The bacterial strains were initially tested for solubilization of inorganic phosphate, indole acetic acid (IAA) production, selected strains were then tested for optimized conditions for IAA production and whether these caused stimulatory effects on bean and maize seedling growth. It was found that all strains had solubilized inorganic phosphate (P), but only 18.05% produced IAA. The best IAA producer was identified by biochemical testing and 16S rDNA sequence analysis as Klebsiella SN 1.1. In addition to being the best IAA producer, this strain was a high P-solubilizer and produced the highest amount of IAA (291.97 ± 0.19 ppm) in culture media supplemented with L-tryptophan. The maximum production of IAA was achieved after 9 days of incubation. The culture requirements were optimized for maximum IAA production. The tested of IAA production by selected isolates was studied in a medium with 0, 0.1, 0.2, 0.5, 0.7, and 0.9% (v/v) L-tryptophan. Low levels (12.6 ppm) of IAA production was recorded without tryptophan addition. Production of IAA in Klebsiella SN 1.1 increased with an increase to 0.2% (v/v) tryptophan concentration. The production of IAA was further confirmed by extraction of crude IAA from this isolate and subsequent Thin Layer Chromatography (TLC) analysis. A specific spot from the extracted IAA production was found to correspond with a standard spot of IAA with the same R (f) value. The Klebsiella strain SN 1.1 also demonstrated stimulatory effects on bean seedlings in vivo. PMID:20552360

Chaiharn, Mathurot; Lumyong, Saisamorn

2011-01-01

158

Numerical optimization of the interface shape at the VGF growth of semiconductor crystals in a traveling magnetic field  

NASA Astrophysics Data System (ADS)

For the first time the efficiency of a traveling magnetic field (TMF) generated inside a vertical gradient freeze (VGF) equipment of industrial scale is computed numerically. The TMF is induced in a combined heater-magnet module consisting of three coil segments operating with phase shift. A charge of 6 kg Ge in a cylindrical pBN container with diameter of 110 mm is taken as model arrangement. In the focus is the study of the interaction between the induced Lorentz force field and the buoyancy-driven convection to find out the optimal field parameters, like frequency and phase shift, for achievement of a slightly convex melt-solid interface and temperature stable growth regime. The flow patterns and interface morphology as functions of the H/ D aspect ratio ( H — melt height, D — melt diameter) in the course of the crystallization process are investigated. It turns out that there is only a narrow Lorentz force region at low frequencies that is able to control a laminar time-independent melt flow regime. The validity of the numerical results is supported by magnetic force measurements on a dummy within the heater-magnet module positioned inside the industrial VGF furnace "Kronos".

Frank-Rotsch, Ch.; Jockel, D.; Ziem, M.; Rudolph, P.

2008-04-01

159

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

PubMed Central

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

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

2012-01-01

160

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)

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.

Miyauchi, T.; Machimura, T.

2013-12-01

161

Optimization of microencapsulated recombinant CHO cell growth, endostatin production, and stability of microcapsule in vivo.  

PubMed

Microencapsulation of recombinant cells secreting endostatin offers a promising approach to tumor gene therapy in which therapeutic protein is delivered in a sustainable and long-term fashion by encapsulated recombinant cells. However, the studies of cell growth and protein production in vivo are very limited. In this study, the effects of microencapsulation parameters on in vivo cell growth, endostatin production, and microcapsule stability after implantation in the peritoneal cavity of mice were for the first time investigated. Microcapsules with liquid core reached higher cell density and endostatin production at day 18 than microcapsules with solid core. There was no significant difference in stability whether the core of the microcapsule was solid or liquid. Decrease in microcapsule size increased the stability of microcapsule. The microcapsules kept intact in the peritoneal cavity of mice after 36 days of implantation when the microcapsules size was 240 microm in diameter, which gave rise to high endostatin production as well. The optimized microencapsulation conditions for in vivo implantation are liquid core and 240 microm in diameter. This study provides useful information for antiangiogenic gene therapy to tumors using microencapsulated recombinant cells. PMID:17497679

Zhang, Ying; Wang, Wei; Xie, Yubing; Yu, Weiting; Lv, Guojun; Guo, Xin; Xiong, Ying; Ma, Xiaojun

2008-01-01

162

Growth optimization during III-nitride multiwafer MOVPE using real-time curvature, reflectance and true temperature measurements  

NASA Astrophysics Data System (ADS)

We employed a newly developed wafer-selective curvature, reflectance and temperature sensor (EpiCurveTT ®) in an AIX2600HT Planetary Reactor ®. Growth of GaN on sapphire as well as AlGaN and InGaN heterostructures with different material compositions were monitored in real time. During growth of a laser-diode text structure the impact of water curvature on wavelength uniformity across the water is demonstrated. Here, the known drastic dependence of indium incorporation on growth temperature requires a uniform substrate surface temperature and therefore a flat wafer during growth of the MQW region. Wafer bowing depending on substrate properties, growth temperature and the insertion of a strain-compensating interlayer is carefully examined to optimize the growth procedure.

Brunner, F.; Hoffmann, V.; Knauer, A.; Steimetz, E.; Schenk, T.; Zettler, J.-T.; Weyers, M.

2007-01-01

163

Growth in Literacy and Numeracy Achievement: Evidence and Explanations of a Summer Slowdown in Low Socio-Economic Schools  

ERIC Educational Resources Information Center

The phenomenon of summer slide or setback has gained a great deal of attention in the USA. It is understood to account for as much as 80% of the difference in achievement for students between low and high socio-economic families over their elementary schooling. In a mixed method longitudinal study of reforms in low socio-economic school…

Vale, Colleen; Weaven, Mary; Davies, Anne; Hooley, Neil; Davidson, Kristy; Loton, Daniel

2013-01-01

164

Consumption Growth Rate Fuelled by Tax Cuts – Achieving Last Year's Christmas Sales Figures would be a Success  

Microsoft Academic Search

Tax cuts like those of 1 January 2000 drive consumer demand, even though only part of the liquidity thus gained will be spent on consumption, whereas savings grow to an even greater extent. The propensity to save rises, at least in the short term, as is the case when the economy is on an upswing. The effect achieved by the

Michael Wüger

2000-01-01

165

Math and Science Achievement in English Language Learners: Multivariate Latent Growth Modeling of Predictors, Mediators, and Moderators  

ERIC Educational Resources Information Center

The effectiveness of various strategies for educating the growing U.S. population of English language learners (ELLs) has attracted a great deal of controversy. Bilingual education theory posits that retention and continued development of native language (L1) skills facilitate academic achievement through two mediating mechanisms. First, L1…

Guglielmi, R. Sergio

2012-01-01

166

Optimization of nutritional compositions of growth medium for Chlorella sp. FJ3 growth kinetics in batch and continuous-flow photoreactors.  

PubMed

This study investigates improvement to culture medium for specific growth rate of Chlorella sp. FJ3 using a fractional factorial design for 32 experiments with six variable components. Six tested components were NaNO3 (0.5 or 3.0 g/l), K2HPO4 (0.01 or 0.06 g/l), MgSO4 7H2O (0.05 or 1.0 g/l), CaCl2 x 2H2O (0.01 or 0.06 g/l), ferric ammonium citrate (0.002 or 0.02 g/l) and NaCl (0.5 or 5.0 g/l). Magnesium sulphate and interaction between magnesium sulphate and ferric ammonium citrate were found to be critical for the cultivation of Chlorella sp. FJ3. The optimal concentrations of MgSO4 x 7H2O and ferric ammonium citrate were found to be 2.0 and 0.35 g/l, respectively. The concentration of carbonate (CO3(2-)) in effluent confirmed that the optimized culture medium was associated with a high carbonate utilization rate and specific growth rate during a transient period in batch and continuous-flow tests. The extent of growth of strain FJ3 in the optimized medium was 1.61 times greater than that in a non-optimized medium in the batch test. In the continuous-flow test, the maximum growth of Chlorella strain FJ3 in the optimized medium was 1.77 times higher than that in a non-optimized medium. The rate of CO3(2-) fixation in the non-optimized and the optimized media was 339 mg/l-day and 887 mg/l-day, respectively, in the steady state. These experimental and modelling results indicated that optimization of concentration in nutritional compositions in the culture medium enhanced the capacity of Chlorella sp. FJ3 for inorganic carbon fixation in batch and continuous-flow modes of photoreactors. PMID:24527649

Leu, Jyh-Yih; Lin, Yen-Hui

2013-01-01

167

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

PubMed Central

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

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

2009-01-01

168

Towards a monolithically integrated III-V laser on silicon: optimization of multi-quantum well growth on InP on Si  

NASA Astrophysics Data System (ADS)

High-quality InGaAsP/InP multi-quantum wells (MQWs) on the isolated areas of indium phosphide on silicon necessary for realizing a monolithically integrated silicon laser is achieved. Indium phosphide layer on silicon, the pre-requisite for the growth of quantum wells is achieved via nano-epitaxial lateral overgrowth (NELOG) technique from a defective seed indium phosphide layer on silicon. This technique makes use of epitaxial lateral overgrowth (ELOG) from closely spaced (1 µm) e-beam lithography-patterned nano-sized openings (˜300?nm) by low-pressure hydride vapor phase epitaxy. A silicon dioxide mask with carefully designed opening patterns and thickness with respect to the opening width is used to block the defects propagating from the indium phosphide seed layer by the so-called necking effect. Growth conditions are optimized to obtain smooth surface morphology even after coalescence of laterally grown indium phosphide from adjacent openings. Surface morphology and optical properties of the NELOG indium phosphide layer are studied using atomic force microscopy, cathodoluminescence and room temperature µ-photoluminescence (µ-PL) measurements. Metal organic vapor phase epitaxial growth of InGaAsP/InP MQWs on the NELOG indium phosphide is conducted. The mask patterns to avoid loading effect that can cause excessive well/barrier thickness and composition change with respect to the targeted values is optimized. Cross-sectional transmission electron microscope studies show that the coalesced NELOG InP on Si is defect-free. PL measurement results indicate the good material quality of the grown MQWs. Microdisk (MD) cavities are fabricated from the MQWs on ELOG layer. PL spectra reveal the existence of resonant modes arising out of these MD cavities. A mode solver using finite difference method indicates the pertinent steps that should be adopted to realize lasing.

Kataria, H.; Junesand, C.; Wang, Z.; Metaferia, W.; Sun, Y. T.; Lourdudoss, S.; Patriarche, G.; Bazin, A.; Raineri, F.; Mages, P.; Julian, N.; Bowers, J. E.

2013-09-01

169

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

E-print Network

2012 Available online 17 March 2012 Keywords: Chlorella CO2 Dynamic optimization Inhibition Oneoff pulse Simulink a b s t r a c t This study tested the growth of three algal species (Chlorella sp-bioreactors, and the experimental results verified that the flue gas pulses could reduce flue gas inhibition and improve Chlorella

Subramanian, Venkat

170

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

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

Peng, Huei

171

Critical parameters for growth of optimized GaN and InGaN/GaN MQW structures on freestanding HVPE GaN substrates by MOCVD  

NASA Astrophysics Data System (ADS)

With the continued improvement and availability of freestanding Nitride substrates, such as those grown by HVPE, these substrates are becoming more commonly used for growth and device applications. However, even with a reduced dislocation density as compared to heteroepitaxially grown GaN layers on sapphire or SiC, devices fabricated on these substrates are often less efficient. One reason for this is that generally growth is carried out using optimized conditions for growth on non-native substrates. In this work optimization of the growth conditions was carried out for GaN layers and InGaN/GaN MQW structures on freestanding HVPE GaN substrates. It was found that the optimized conditions for growth on these substrates are different as compared to growth on GaN on sapphire templates. The results of the optimization and the differences in the growth will be presented along with insight into the differences seen experimentally.

Grandusky, James; Jindal, Vibhu; Tripathi, Neeraj; Shahedipour-Sandvik, Fatemeh; Vertiatchikh, Alexei; Dunne, Greg; Lu, Hai; Kaminsky, Edmund; Melkote, Rajesh

2007-03-01

172

A Novel Hybridization of Applied Mathematical, Operations Research and Risk-based Methods to Achieve an Optimal Solution to a Challenging Subsurface Contamination Problem  

NASA Astrophysics Data System (ADS)

The objective of the project is the creation of a new, computationally based, approach to the collection, evaluation and use of data for the purpose of determining optimal strategies for investment in the solution of remediation of contaminant source areas and similar environmental problems. The research focuses on the use of existing mathematical tools assembled in a unique fashion. The area of application of this new capability is optimal (least-cost) groundwater contamination source identification; we wish to identify the physical environments wherein it may be cost-prohibitive to identify a contaminant source, the optimal strategy to protect the environment from additional insult and formulate strategies for cost-effective environmental restoration. The computational underpinnings of the proposed approach encompass the integration into a unique of several known applied-mathematical tools. The resulting tool integration achieves the following: 1) simulate groundwater flow and contaminant transport under uncertainty, that is when the physical parameters such as hydraulic conductivity are known to be described by a random field; 2) define such a random field from available field data or be able to provide insight into the sampling strategy needed to create such a field; 3) incorporate subjective information, such as the opinions of experts on the importance of factors such as locations of waste landfills; 4) optimize a search strategy for finding a potential source location and to optimally combine field information with model results to provide the best possible representation of the mean contaminant field and its geostatistics. Our approach combines in a symbiotic manner methodologies found in numerical simulation, random field analysis, Kalman filtering, fuzzy set theory and search theory. Testing the algorithm for this stage of the work, we will focus on fabricated field situations wherein we can a priori specify the degree of uncertainty associated with the target locations and the field parameters. We will vary the uncertainty in these two factors to establish the relationship between the degree of uncertainty associated with them and the overall project costs. Of particular interest to us will be the sensitivity of the final determination of 'unidentifiable' and the various forms of uncertainty we enter into the experiments. By examining these test problems the algorithm can be refined and verified. The results of this research will show the accuracy and use of uncertainty in determining the source. The proposed research will seek to develop a new, computationally based, approach to the collection, evaluation and use of data for the purpose of determining optimal strategies for investment in the search for groundwater contamination sources. More specifically it will focus on those circumstances where it is economically infeasible to find a source or sources due to lack of know and field parameter uncertainty. The research will focus on the integration of several applied mathematical tools to achieve this objective. The resulting algorithm will be tested using fabricated, yet realistic field situations. The metric of success is whether the critical source of uncertainty in determining whether or not a source can be found is identifiable and its sensitivity.

Johnson, K. D.; Pinder, G. F.

2013-12-01

173

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

PubMed

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

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

2012-04-11

174

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

NASA Astrophysics Data System (ADS)

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 × 1018 cm-3, the resistivity is 0.9 ? cm and the mobility is 3.03 cm2 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.

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

2012-04-01

175

Modeling dynamic urban growth using hybrid cellular automata and particle swarm optimization  

NASA Astrophysics Data System (ADS)

Conventional raster-based cellular automata (CA) confront many difficulties because of cell size and neighborhood sensitivity. Alternatively, vector CA-based models are very complex and difficult to implement. We present a hybrid cellular automata (HCA) model as a combination of cellular structure and vector concept. The space is still defined by a set of cells, but rasterized spatial objects are also utilized in the structure of transition rules. Particle swarm optimization (PSO) is also used to calculate the urbanization probability of cells based on their distance from the development parameters. The proposed model is applied to Landsat satellite imagery of the city of Tehran, Iran with 28.5-m spatial resolution to simulate the urban growth from 1988 to 2010. Statistical comparison of the ground truth and the simulated image using a kappa coefficient shows an accuracy of 83.42% in comparison to the 81.13% accuracy for the conventional Geo-CA model. Moreover, decreasing the spatial resolution by a factor of one-fourth has reduced the accuracy of the HCA and Geo-CA models by 1.19% and 3.04%, respectively, which shows the lower scale sensitivity of the proposed model. The HCA model is developed to have the simplicity of cellular structure together with optimum features of vector models.

Rabbani, Amirhosein; Aghababaee, Hossein; Rajabi, Mohammad A.

2012-01-01

176

YBCO/Ag composites through a preform optimized infiltration and growth process yield high current densities  

NASA Astrophysics Data System (ADS)

Bulk YBa2Cu3O7 - ? (YBCO)/Ag composites with a homogeneous distribution of fine and spherical particles of metallic silver and Y2BaCuO5 (Y-211) have been fabricated using a preform optimized infiltration growth process (POIGP). The effect of two different methods of introducing silver, one directly into the Y-211 preform and the other into the liquid phase source placed above the Y-211 preform, on the microstructures and current densities is investigated. Our results show that the latter method is far superior to the former. The samples obtained by introducing silver through liquid phases are nearly free from defects like voids, pores, macro-cracks and platelet gaps. Current densities in excess of 103 A cm - 2 up to fields of 2.7 T have been recorded in these samples at 77 K. The problems reported in literature with respect to inhomogeneity in the distribution of both Y-211 and Ag particles in the Y-123 matrix and the associated spatial non-uniformity in the current density are successfully resolved in the present work.

Devendra Kumar, N.; Rajasekharan, T.; Seshubai, V.

2011-08-01

177

Ping-pong amplification of a retroviral vector achieves high-level gene expression: human growth hormone production.  

PubMed Central

Retroviral vectors offer major advantages for gene transfer studies but have not been useful for producing proteins in large quantities. This deficiency has resulted in part from interference to superinfection, which limits the numbers of active proviruses in cells. Recently, we found that these vectors amplify when they are added as calcium phosphate precipitates to cocultures of cells that package retroviruses into ecotropic and amphotropic host range envelopes. Helper-free virions from either cell type can infect the other without interference, resulting in theoretically limitless back-and-forth (ping-pong) vector replication. In initial studies, however, amplifications of a vector that contained the human growth hormone gene ceased when the hormone produced was 0.3% or less of cellular protein synthesis. This limit was caused by two factors. First, recombinant shutoff viruses that are replication defective and encode envelope glycoproteins form at a low probability during any round of the vector replication cycle and these spread in cocultures, thereby establishing interference. Single cells in shutoff cocultures therefore synthesize both ecotropic and amphotropic envelope glycoproteins, and they release promiscuous (presumably hybrid) virions. The probability of forming shutoff viruses before the vector had amplified to a high multiplicity was reduced by using small cocultures. Second, cells with large numbers of proviruses are unhealthy and their proviral expression can be unstable. Stable expresser cell clones were obtained by selection. Thereby, cell lines were readily obtained that stably produce human growth hormone as 4 to 6% of the total protein synthesis. A ping-pong retroviral vector can be used for high-level protein production in vertebrate cells. Images PMID:2352330

Kozak, S L; Kabat, D

1990-01-01

178

Effects of nonlinear physical processes on optimal error growth in predictability experiments of the Kuroshio Large Meander  

NASA Astrophysics Data System (ADS)

Within a 1.5-layer shallow-water model, the effects of nonlinear physical processes on the optimal error growth in the predictability experiments of the Kuroshio Large Meander (LM) are investigated. To clarify these effects, we use both the conditional nonlinear optimal perturbation (CNOP) and the first singular vector (FSV) methods. By examining the nonlinear evolution of the CNOPs and the FSVs, we find that the nonlinear physical processes play an important role in the error growth, in particular for the initial errors with large amplitudes. The specific roles of nonlinear processes in error growth are identified by determining the error development in modified nonlinear equations in which particular terms are neglected. The results demonstrate that advection of momentum perturbations, associated with the nonlinear development of barotropic instabilities, tend to enhance the evolution of the errors and cause the forecasted Kuroshio Large Meander to be strengthened. The nonlinear process related to the divergence of velocity perturbations caused by upper-layer thickness perturbations enhances the optimal error growth, whereas the advection of upper-layer thickness perturbations by velocity perturbations suppresses it.

Wang, Qiang; Mu, Mu; Dijkstra, Henk A.

2013-12-01

179

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

PubMed Central

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

Wahl, Anna-Sophia; Schwab, Martin E.

2014-01-01

180

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...

181

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

NASA Astrophysics Data System (ADS)

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.

Jeganathan, K.; Shimizu, M.

2014-09-01

182

A Novel Liquid Medium for the Efficient Growth of the Salmonid Pathogen Piscirickettsia salmonis and Optimization of Culture Conditions  

PubMed Central

Piscirickettsia salmonis is the bacterium that causes Piscirickettsiosis, a systemic disease of salmonid fish responsible for significant economic losses within the aquaculture industry worldwide. The growth of the bacterium for vaccine formulation has been traditionally accomplished by infecting eukaryotic cell lines, a process that involves high production costs and is time-consuming. Recent research has demonstrated that it is possible to culture pure P. salmonis in a blood containing (cell-free) medium. In the present work we demonstrate the growth of P. salmonis in a liquid medium free from blood and serum components, thus establishing a novel and simplified bacteriological medium. Additionally, the new media reported provides improved growth conditions for P. salmonis, where biomass concentrations of approximately 800 mg cell dry weight L?1 were obtained, about eight times higher than those reported for the blood containing medium. A 2- level full factorial design was employed to evaluate the significance of the main medium components on cell growth and an optimal temperature range of 23–27°C was determined for the microorganism to grow in the novel liquid media. Therefore, these results represent a breakthrough regarding P. salmonis research in order to optimize pure P. salmonis growth in liquid blood and serum free medium. PMID:24039723

Marshall, Sergio H.; Henriquez, Vitalia; Gomez, Fernando A.; Martinez, Irene; Altamirano, Claudia

2013-01-01

183

Optimization and effects of different culture conditions on growth of Halomicronema hongdechloris - a filamentous cyanobacterium containing chlorophyll f  

PubMed Central

A chlorophyll f containing cyanobacterium, Halomicronema hongdechloris (H. hongdechloris) was isolated from a stromatolite cyanobacterial community. The extremely slow growth rate of H. hongdechloris has hindered research on this newly isolated cyanobacterium and the investigation of chlorophyll f-photosynthesis. Therefore, optimizing H. hongdechloris culture conditions has become an essential requirement for future research. This work investigated the effects of various culture conditions, essential nutrients and light environments to determine the optimal growth conditions for H. hongdechloris and the biosynthetic rate of chlorophyll f. Based on the total chlorophyll concentration, an optimal growth rate of 0.22 ± 0.02 day-1(doubling time: 3.1 ± 0.3 days) was observed when cells were grown under continuous illumination with far-red light with an intensity of 20 ?E at 32°C in modified K + ES seawater (pH 8.0) with additional nitrogen and phosphor supplements. High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes ~10% of the total chlorophyll from cells grown under far-red light. Fluorescence confocal image analysis demonstrated changes of photosynthetic membranes and the distribution of photopigments in response to different light conditions. The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis. The implications of the presence of chlorophyll f in H. hongdechloris and its relationship with the ambient light environment are discussed. PMID:24616731

Li, Yaqiong; Lin, Yuankui; Loughlin, Patrick C.; Chen, Min

2014-01-01

184

Correlation between the optimal growth pressures of four Shewanella species and the stabilities of their cytochromes c 5.  

PubMed

Shewanella species live widely in deep-sea and shallow-water areas, and thus grow piezophilically and piezosensitively. Piezophilic and psychrophilic Shewanella benthica cytochrome c 5 (SB cytc 5) was the most stable against guanidine hydrochloride (GdnHCl) and thermal denaturation, followed by less piezophilic but still psychrophilic Shewanella violacea cytochrome c 5 (SV cytc 5). These two were followed, as to stability level, by piezosensitive and mesophilic Shewanella amazonensis cytochrome c 5 (SA cytc 5), and piezosensitive and psychrophilic Shewanella livingstonensis cytochrome c 5 (SL cytc 5). The midpoint GdnHCl concentrations of SB cytc 5, SV cytc 5, SL cytc 5, and SA cytc 5 correlated with the optimal growth pressures of the species, the correlation coefficient value being 0.93. A similar trend was observed for thermal denaturation. Therefore, the stability of each cytochrome c 5 is related directly to its host's optimal growth pressure. Phylogenetic analysis indicated that Lys-37, Ala-41, and Leu-50 conserved in piezosensitive SL cytc 5 and SA cytc 5 are ancestors of the corresponding residues in piezophilic SB cytc 5 and SV cytc 5, Gln, Thr, and Lys, respectively, which might have been introduced during evolution on adaption to environmental pressure. The monomeric Shewanella cytochromes c 5 are suitable tools for examining protein stability with regard to the optimal growth pressures of the source species. PMID:24699850

Masanari, Misa; Wakai, Satoshi; Ishida, Manabu; Kato, Chiaki; Sambongi, Yoshihiro

2014-05-01

185

Statistical Optimization of Medium Components for Mass Production of Plant Growth-Promoting Microbial Inoculant Pseudomonas trivialis BIHB 745 (MTCC5336).  

PubMed

Optimizing nutritional requirements for mass production of microbial inoculants in shortened time has relevance for their economical field application. Therefore, the present study aimed at selecting suitable growth medium, optimizing its components, and up-scaling inoculum production for plant growth-promoting Pseudomonas trivialis BIHB 745. Of the different media tested, the culture exhibited maximal viable colony count in trypticase soya broth with 17.6 % increased biomass on optimizing levels of carbon source, nitrogen source, and NaCl using response surface methodology. A twofold higher biomass with 9 h shorter incubation period was obtained in optimized medium in a bioreactor in comparison to shake flasks. PMID:25320429

Vyas, Pratibha; Rahi, Praveen; Chadha, B S; Gulati, Arvind

2014-06-01

186

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

E-print Network

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

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

2006-12-05

187

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

NASA Astrophysics Data System (ADS)

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.

Bess, John Darrell

188

Neutral pH hydrogen-enriched electrolyzed water achieves tumor-preferential clonal growth inhibition over normal cells and tumor invasion inhibition concurrently with intracellular oxidant repression.  

PubMed

The properties and effects of neutral pH hydrogen-enriched electrolyzed water (NHE water) on tumor cells were examined. NHE water diminished hydroxyl radicals as demonstrated by ESR in a cell-free system. Human tongue carcinoma cells HSC-4 were inhibited for either colony formation efficiencies or colony sizes by NHE water without significant inhibition to normal human tongue epithelial-like cells DOK. Furthermore, NHE water caused growth inhibition, cell degeneration, and inhibition of invasion through the reconstituted basement membrane to human fibrosarcoma cells HT-1080. Intracellular oxidants such as hydroperoxides and hydrogen peroxides were scavenged in HSC-4 or HT-1080 cells by NHE water. In the human oral cavity, a dissolved hydrogen concentrations (DH) of NHE water was drastically declined from 1.1 to 0.5 ppm, but settled to 0.3-0.4 ppm until 180 s, upon static holding without gargling. Thus, NHE water was shown to achieve tumor-preferential growth inhibition and tumor invasion together with scavenging of intracellular oxidants, and is expected as a preventive material against tumor progression and invasion. PMID:19192719

Saitoh, Yasukazu; Okayasu, Hajime; Xiao, Li; Harata, Yoshikazu; Miwa, Nobuhiko

2008-01-01

189

Optimizing cultivation strategies for robust algal growth and consequent removal of inorganic nutrients in pretreated livestock effluent.  

PubMed

Dilution was employed as a pretreatment strategy to increase light transmittance and decrease ammonia toxicity in piggery effluent prior to the cultivation of microalgae. The dilution effect was quantitatively determined based on both the maximum specific nutrient consumption rate and the maximum growth coefficient to minimize the usage of diluent. The biomass productivity of microalgae was also evaluated to select the best species among the five different candidates examined. A 20-fold dilution of piggery wastewater resulted in decreased chromaticity (584 mg Pt-Co L(-1)) and total nitrogen (76 mg L(-1)), on which the microalgae cultivation was more effective for an algal growth compared to the other dilution factors. If the initial cell concentration of Scenedesmus quadricauda increased, the production of biomass tended to improve. Robust growth and harvesting of S. quadricauda were achieved, and the associated consistent removal of inorganic nutrients was accomplished during the semi-continuous cultivation of the best species. PMID:25138601

Kim, Hyun-Chul; Choi, Wook Jin; Ryu, Jun Hee; Maeng, Sung Kyu; Kim, Han Soo; Lee, Byung-Chan; Song, Kyung Guen

2014-10-01

190

Optimization of culture conditions for growth of the green alga Haematococcus pluvialis  

Microsoft Academic Search

The effects of light intensity, inoculum volume, sodium nitrate and carbon dioxide concentrations on the growth of Haematococcus pluvialis were investigated using response surface methodology (RSM). All the four variables exhibited significant effects on growth and can be related (r = 0.926, P = 0.01) by a second-order polynomial consisting of linear, quadratic and interaction terms. The total quadratic effect

R. Sarada; Sila Bhattacharya; G. A. Ravishankar

2002-01-01

191

Optimization of plant growth-promoting bacteria-assisted phytostabilization of mine tailings  

Microsoft Academic Search

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

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

2009-01-01

192

On the role of plant mitochondrial metabolism and its impact on photosynthesis in both optimal and sub-optimal growth conditions.  

PubMed

Given that the pathways of photosynthesis and respiration catalyze partially opposing processes, it follows that their relative activities must be carefully regulated within plant cells. Recent evidence has shown that the components of the mitochondrial electron transport chain are essential for the proper maintenance of intracellular redox gradients, to allow considerable rates of photorespiration and in turn efficient photosynthesis. Thus considerable advances have been made in understanding the interaction between respiration and photosynthesis during the last decades and the potential mechanisms linking mitochondrial function and photosynthetic efficiency will be reviewed. Despite the fact that manipulation of various steps of mitochondrial metabolism has been demonstrated to alter photosynthesis under optimal growth conditions, it is likely that these changes will, by and large, not be maintained under sub-optimal situations. Therefore producing plants to meet this aim remains a critical challenge. It is clear, however, that although there have been a range of studies analysing changes in respiratory and photosynthetic rates in response to light, temperature and CO2, our knowledge of the environmental impact on these processes and its linkage still remains fragmented. We will also discuss the metabolic changes associated to plant respiration and photosynthesis as important components of the survival strategy as they considerably extend the period that a plant can withstand to a stress situation. PMID:23456269

Araújo, Wagner L; Nunes-Nesi, Adriano; Fernie, Alisdair R

2014-02-01

193

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

E-print Network

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 ...

Steiner, Stephen Alan, III

2006-01-01

194

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

195

Suppression of phase separation of AlGaN during lateral growth and fabrication of high-efficiency UV-LED on optimized AlGaN  

Microsoft Academic Search

Phase separation of AlGaN is found to occur during growth on periodically trenched GaN, and it sometimes causes crack formation. The rate of separation can be suppressed by decreasing NH3 flow rate in the gas phase. We can optimize the growth condition for AlGaN growth, thereby fabricating UV-LED with an emission wavelength of 352nm and output power of 0.6mW at

Motoaki Iwaya; Shinji Terao; Tomoaki Sano; Tsutomu Ukai; Ryo Nakamura; Satoshi Kamiyama; Hiroshi Amano; Isamu Akasaki

2002-01-01

196

Modeling and Design of Optimal Growth Media from Plant - Based Gas and Liquid Fluxes  

Microsoft Academic Search

Design solutions for robust and optimal supply of water, nutrients, and gases within plant root media in micro- and reduced-gravity are essential for successful integration of plants as an important bioregenerative component of advanced life support systems. Many of the confounding and 'unknown' microgravity effects associated with previous plant research on Mir and on the International Space Station (ISS), may

Scott B. Jones; Robert Heinse; Gail E. Bingham

197

Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors  

PubMed Central

Introduction Platelet-rich plasma (PRP) is nowadays widely applied in different clinical scenarios, such as orthopedics, ophthalmology and healing therapies, as a growth factor pool for improving tissue regeneration. Studies into its clinical efficiency are not conclusive and one of the main reasons for this is that different PRP preparations are used, eliciting different responses that cannot be compared. Platelet quantification and the growth factor content definition must be defined in order to understand molecular mechanisms behind PRP regenerative strength. Standardization of PRP preparations is thus urgently needed. Methods PRP was prepared by centrifugation varying the relative centrifugal force, temperature, and time. Having quantified platelet recovery and yield, the two-step procedure that rendered the highest output was chosen and further analyzed. Cytokine content was determined in different fractions obtained throughout the whole centrifugation procedure. Results Our method showed reproducibility when applied to different blood donors. We recovered 46.9 to 69.5% of total initial platelets and the procedure resulted in a 5.4-fold to 7.3-fold increase in platelet concentration (1.4 × 106 to 1.9 × 106 platelets/?l). Platelets were highly purified, because only <0.3% from the initial red blood cells and leukocytes was present in the final PRP preparation. We also quantified growth factors, cytokines and chemokines secreted by the concentrated platelets after activation with calcium and calcium/thrombin. High concentrations of platelet-derived growth factor, endothelial growth factor and transforming growth factor (TGF) were secreted, together with the anti-inflammatory and proinflammatory cytokines interleukin (IL)-4, IL-8, IL-13, IL-17, tumor necrosis factor (TNF)-? and interferon (IFN)-?. No cytokines were secreted before platelet activation. TGF-?3 and IFN? were not detected in any studied fraction. Clots obtained after platelet coagulation retained a high concentration of several growth factors, including platelet-derived growth factor and TGF. Conclusions Our study resulted in a consistent PRP preparation method that yielded a cytokine and growth factor pool from different donors with high reproducibility. These findings support the use of PRP in therapies aiming for tissue regeneration, and its content characterization will allow us to understand and improve the clinical outcomes. PMID:23759113

2013-01-01

198

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

NASA Astrophysics Data System (ADS)

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.

Pandit, Abhay Smashikant

199

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

Microsoft Academic Search

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

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

1996-01-01

200

In situ control and optimization of GaN thin film growth by molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

Single crystalline gallium nitride (GaN) thin films were grown by various molecular beam epitaxy (MBE) methods using two different nitrogen precursors. Time of flight mass spectroscopy of recoiled ions (TOF-MSRI) in combination with reflection high energy electron diffraction (RHEED) were utilized to investigate in-situ the nitridation of the substrates, the nucleation of the low temperature buffer layers and the final epilayer characteristics. First, electron cyclotron resonance (ECR) MBE was investigated. With the commercial ASTeX ECR plasma source, growth rates were limited to a maximum of 2000 A/hr and the layers were optically inactive. The use of a custom made aperture, to remove the ionic species from the ECR flux resulted in growth rates as high as 1 mum/hr. Next, gas source MBE, using ammonia and Ga, was studied in GaN thin film growth. The chemical decomposition and incorporation of NHsb3 in the thin films were studied for different growth conditions. GaN epilayers grown with a low temperature buffer layer exhibited superior film quality as identified by TEM, PL and AFM results. A direct correlation between in-situ TOF-MSRI and ex-situ PL results was observed. Samples with a low Ga/N ratio in TOF-MSRI show the best optical quality. Finally, chemical beam epitaxy (CBE) was utilized for the first time in GaN thin film growth. Triethyl gallium and ammonia were used as precursors. TOF-MSRI determined that buffer layers could not be deposited directly on the sapphire substrate using the CBE precursors. The use of TEG and ECR-Nsb2 species allowed the growth of crystalline buffers. The growth temperature and Nsb2 flow affect strongly the crystallinity of these buffer layers. Amorphous and polycrystalline buffer layers became island-like upon annealing to 900sp°C in vacuum while the crystalline buffer layers remained unchanged. TOF-MSRI studies found that the residual carbon level is highly temperature dependent and influenced greatly the surface morphology and crystallinity (from RHEED). It is only within a narrow temperature window, 800-825sp°C, that the carbon level is minimized. Within that range, GaN epilayers with strong room temperature PL signals were obtained.

Kim, Esther

201

Improving Achievement.  

ERIC Educational Resources Information Center

Improving student achievement hinges on adopting effective, research-based learning practices and activities. These include parent involvement, graded homework, direct teaching, aligned time on task, tutoring, cooperative learning, mastery learning, and teaching of learning strategies. Three high-achieving schools are profiled. (MLH)

Cawelti, Gordon

1999-01-01

202

Different Levels of Catabolite Repression Optimize Growth in Stable and Variable Environments  

PubMed Central

Organisms respond to environmental changes by adapting the expression of key genes. However, such transcriptional reprogramming requires time and energy, and may also leave the organism ill-adapted when the original environment returns. Here, we study the dynamics of transcriptional reprogramming and fitness in the model eukaryote Saccharomyces cerevisiae in response to changing carbon environments. Population and single-cell analyses reveal that some wild yeast strains rapidly and uniformly adapt gene expression and growth to changing carbon sources, whereas other strains respond more slowly, resulting in long periods of slow growth (the so-called “lag phase”) and large differences between individual cells within the population. We exploit this natural heterogeneity to evolve a set of mutants that demonstrate how the frequency and duration of changes in carbon source can favor different carbon catabolite repression strategies. At one end of this spectrum are “specialist” strategies that display high rates of growth in stable environments, with more stringent catabolite repression and slower transcriptional reprogramming. The other mutants display less stringent catabolite repression, resulting in leaky expression of genes that are not required for growth in glucose. This “generalist” strategy reduces fitness in glucose, but allows faster transcriptional reprogramming and shorter lag phases when the cells need to shift to alternative carbon sources. Whole-genome sequencing of these mutants reveals that mutations in key regulatory genes such as HXK2 and STD1 adjust the regulation and transcriptional noise of metabolic genes, with some mutations leading to alternative gene regulatory strategies that allow “stochastic sensing” of the environment. Together, our study unmasks how variable and stable environments favor distinct strategies of transcriptional reprogramming and growth. PMID:24453942

New, Aaron M.; Cerulus, Bram; Govers, Sander K.; Perez-Samper, Gemma; Zhu, Bo; Boogmans, Sarah; Xavier, Joao B.; Verstrepen, Kevin J.

2014-01-01

203

Different levels of catabolite repression optimize growth in stable and variable environments.  

PubMed

Organisms respond to environmental changes by adapting the expression of key genes. However, such transcriptional reprogramming requires time and energy, and may also leave the organism ill-adapted when the original environment returns. Here, we study the dynamics of transcriptional reprogramming and fitness in the model eukaryote Saccharomyces cerevisiae in response to changing carbon environments. Population and single-cell analyses reveal that some wild yeast strains rapidly and uniformly adapt gene expression and growth to changing carbon sources, whereas other strains respond more slowly, resulting in long periods of slow growth (the so-called "lag phase") and large differences between individual cells within the population. We exploit this natural heterogeneity to evolve a set of mutants that demonstrate how the frequency and duration of changes in carbon source can favor different carbon catabolite repression strategies. At one end of this spectrum are "specialist" strategies that display high rates of growth in stable environments, with more stringent catabolite repression and slower transcriptional reprogramming. The other mutants display less stringent catabolite repression, resulting in leaky expression of genes that are not required for growth in glucose. This "generalist" strategy reduces fitness in glucose, but allows faster transcriptional reprogramming and shorter lag phases when the cells need to shift to alternative carbon sources. Whole-genome sequencing of these mutants reveals that mutations in key regulatory genes such as HXK2 and STD1 adjust the regulation and transcriptional noise of metabolic genes, with some mutations leading to alternative gene regulatory strategies that allow "stochastic sensing" of the environment. Together, our study unmasks how variable and stable environments favor distinct strategies of transcriptional reprogramming and growth. PMID:24453942

New, Aaron M; Cerulus, Bram; Govers, Sander K; Perez-Samper, Gemma; Zhu, Bo; Boogmans, Sarah; Xavier, Joao B; Verstrepen, Kevin J

2014-01-01

204

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

NASA Astrophysics Data System (ADS)

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.

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

205

Optimization of ion assist beam deposition of magnesium oxide template films during initial nucleation and growth  

SciTech Connect

Recent efforts in investigating the mechanism of ion beam assisted deposition (IBAD) of biaxially textured thin films of magnesium oxide (MgO) template layers have shown that the texture develops suddenly during the initial 2 nm of deposition. To help understand and tune the behavior during this initial stage, we pre-deposited thin layers of MgO with no ion assist prior to IBAD growth of MgO. We found that biaxial texture develops for pre-deposited thicknesses < 2 nm, and that the thinnest layer tested, at 1 nm, resulted in the best qualitative RHEED image, indicative of good biaxial texture development. The texture developed during IBAD growth on the 1.5 nm pre-deposited layer is slightly worse and IBAD growth on the 2 nm pre-deposited layer produces a fiber texture. Application of these layers on an Al{sub 2}O{sub 3} starting surface, which has been shown to impede texture development, improves the overall quality of the IBAD MgO and has some of the characteristics of a biaxially texture RHEED pattern. It is suggested that the use of thin (<2 nm) pre-deposited layers may eliminate the need for bed layers like Si{sub 3}N{sub 4} and Y{sub 2}O{sub 3} that are currently thought to be required for proper biaxial texture development in IBAD MgO.

Groves, James R [Los Alamos National Laboratory; Matias, Vladimir [Los Alamos National Laboratory; Stan, Liliana [Los Alamos National Laboratory; De Paula, Raymond F [Los Alamos National Laboratory; Hammond, Robert H [STANFORD UNIV.; Clemens, Bruce M [STANFOED UNIV.

2010-01-01

206

Cardiovascular toxicities: clues to optimal administration of vascular endothelial growth factor signaling pathway inhibitors  

PubMed Central

Several angiogenesis inhibitors have been approved for commercial use and many additional agents are under development for the treatment of various malignancies. Cardiovascular toxicities have been increasingly recognized as effects of this entire class of new anticancer therapeutics. There is a limited but growing understanding of the mechanism of action of these drugs in the human cancer patient and the factors affecting the therapeutic index. In addition to reviewing current concepts for the cardiovascular toxicities of angiogenesis inhibitors, we discuss how better understanding the pharmacologic basis for these effects could optimize their use for individual patients. PMID:19373440

Snider, Kelly L.

2011-01-01

207

Enhancement of Lipid Productivity in Oleaginous Colletotrichum Fungus through Genetic Transformation Using the Yeast CtDGAT2b Gene under Model-Optimized Growth Condition  

PubMed Central

Oleaginous fungi are of special interest among microorganisms for the production of lipid feedstocks as they can be cultured on a variety of substrates, particularly waste lingocellulosic materials, and few fungal strains are reported to accumulate inherently higher neutral lipid than bacteria or microalgae. Previously, we have characterized an endophytic filamentous fungus Colletotrichum sp. DM06 that can produce total lipid ranging from 34% to 49% of its dry cell weight (DCW) upon growing with various carbon sources and nutrient-stress conditions. In the present study, we report on the genetic transformation of this fungal strain with the CtDGAT2b gene, which encodes for a catalytically efficient isozyme of type-2 diacylglycerol acyltransferase (DGAT) from oleaginous yeast Candida troplicalis SY005. Besides the increase in size of lipid bodies, total lipid titer by the transformed Colletotrichum (lipid content ?73% DCW) was found to be ?1.7-fold more than the wild type (lipid content ?38% DCW) due to functional activity of the CtDGAT2b transgene when grown under standard condition of growth without imposition of any nutrient-stress. Analysis of lipid fractionation revealed that the neutral lipid titer in transformants increased up to 1.8-, 1.6- and 1.5-fold compared to the wild type when grown under standard, nitrogen stress and phosphorus stress conditions, respectively. Lipid titer of transformed cells was further increased to 1.7-fold following model-based optimization of culture conditions. Taken together, ?2.9-fold higher lipid titer was achieved in Colletotrichum fungus due to overexpression of a rate-limiting crucial enzyme of lipid biosynthesis coupled with prediction-based bioprocess optimization. PMID:25375973

Dey, Prabuddha; Mall, Nikunj; Chattopadhyay, Atrayee; Chakraborty, Monami; Maiti, Mrinal K.

2014-01-01

208

Outstanding Achievement  

E-print Network

shown leadership, raised awareness of youth issues, in a positive role model, and/or aids local youths to beautify the Borough or improve the cleanliness. Sports: Any athlete, team or coach who has achieved

209

Age and Achievement  

ERIC Educational Resources Information Center

There is continuing controversy about the optimal or appropriate age at which children should start school. The purpose of this study is to examine the relationship between age and achievement. It is an attempt to evaluate the hypothesis that older students fare better academically than their younger classmates. Findings indicate that on average…

Grissom, James B.

2004-01-01

210

Appraising Reading Achievement.  

ERIC Educational Resources Information Center

To determine quality sequence in pupil progress, evaluation approaches need to be used which guide the teacher to assist learners to attain optimally. Teachers must use a variety of procedures to appraise student achievement in reading, because no one approach is adequate. Appraisal approaches might include: (1) observation and subsequent…

Ediger, Marlow

211

Relevance of voltage control, grid reconfiguration and adaptive protection in smart grids and genetic algorithm as an optimization tool in achieving their control objectives  

Microsoft Academic Search

Voltage control, grid reconfiguration and adaptive protection are considered in this paper since they are representative of the various control applications in the context of smart grids which can make significant use of the information and communication technology. All the three control applications have multiple objectives of which some are conflicting and these call for the use of multi-objective optimization

Parvathy Chittur Ramaswamy; Geert Deconinck

2011-01-01

212

Increasing Costs Due to Ocean Acidification Drives Phytoplankton to Be More Heavily Calcified: Optimal Growth Strategy of Coccolithophores  

PubMed Central

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 CaCO3 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 CO2 concentration. PMID:20976167

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

2010-01-01

213

Studies on Growth Kinetics of Serratia marcescens VITSD2 and Optimization of Fermentation Conditions for Serratiopeptidase Production.  

PubMed

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

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

2014-01-01

214

Growth  

NSDL National Science Digital Library

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.

Technology, Massachusetts I.

215

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

PubMed

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

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

2013-07-10

216

Optimized templates for bottom-up growth of high-performance integrated biomolecular detectors.  

PubMed

Electrochemical deposition of metals represents an important approach in the bottom-up fabrication of nanostructures and microstructures. We have used this approach to generate high-performance chip-based biosensors using silicon as a platform for the generation of sensor arrays. Here, we explore the applicability of different materials to support the electrodeposition and identify the parameters that are essential for robust sensor growth. We show that inexpensive materials can be used as templates for electrodeposition, and demonstrate that these low-cost sensors exhibit clinically-relevant levels of sensitivity and specificity. In particular, we prove herein that the glass-based sensors successfully detect E. coli in urine, when present at the 100 cfu ?L(-1) levels found typically in samples of patients with urinary tract infections. PMID:23455732

Lam, Brian; Holmes, Richard D; Das, Jagotamoy; Poudineh, Mahla; Sage, Andrew; Sargent, Edward H; Kelley, Shana O

2013-07-01

217

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

NASA Astrophysics Data System (ADS)

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.

Kamenev, G. K.

2014-08-01

218

Effect of Preform Compaction Pressure on the Final Microstructures and Superconducting Properties of YBa2Cu3O7- ? Superconductors Fabricated by Directionally Solidified Preform Optimized Infiltration Growth Process  

NASA Astrophysics Data System (ADS)

Bulk YBa2Cu3O7- ? (YBCO, Y-123) superconductors with reasonable critical current densities J c are successfully fabricated in relatively short-time durations employing Directionally Solidified Preform Optimized Infiltration Growth Process (DS-POIGP). The effect of preform compaction pressure, applied to Y2BaCuO5 (Y-211) preform prior to the infiltration of liquid phases, on the end microstructures and current densities is investigated. It is found that a preform compaction pressure of 460 MPa resulted in samples with superior microstructures and superconducting properties. YBCO sample fabricated by DS-POIGP under optimized conditions revealed presence of fine-sized Y-211 particles distributed uniformly in the matrix of Y-123 causing large interfacial defect density (Y-211/Y-123). Extensive twinning on a nano-scale with twins in the size range of 40-100 nm is observed in the optimized sample. These microstructural parameters enabled a considerable improvement in the field dependence of J c . Irreversibility fields greater than 5.5 Tesla even at 77 K are achieved in the optimized sample fabricated by DS-POIGP.

Devendra Kumar, N.; Missak Swarup Raju, P.; Pavan Kumar Naik, S.; Rajasekharan, T.; Seshubai, V.

2014-02-01

219

Sub-optimal achievement of guideline-derived lipid goals in management of diabetes patients with atherosclerotic cardiovascular disease, despite high use of evidence-based therapies.  

PubMed

Guidelines recommend aggressive goals for lipid and blood pressure reduction for high risk patients with diabetes mellitus and atherosclerotic coronary disease. However, it remains unclear how many patients achieve treatment goals versus the number of people merely placed on treatment. We conducted an observational study in an academic cardiology clinic. A total of 926 patients with atherosclerotic cardiovascular disease and concomitant diabetes mellitus met criteria. Mean age was 68.4 ± 10.2, 65.6% were male, and 86.8% were Caucasian. By the last visit a high percentage of patients were receiving recommended medications. Mean LDL-cholesterol achieved was 80.4 mg/dl with 40.9% reaching ? 70 mg/dl, and 61.7% reaching SBP ? 130 mmHg. Many patients with diabetes mellitus and atherosclerotic cardiovascular disease are prescribed recommended medications; however, few achieve guidelines-specified therapeutic goals for LDL-cholesterol and blood pressure. Studies evaluating performance improvement should include percentage of patients reaching treatment goals. Mechanisms underlying the treatment gap need to be identified and addressed. PMID:22234950

DeGuzman, Pamela B; Akosah, Kwame O; Simpson, Allan G; Barbieri, Kirk E; Megginson, Gregory C; Goldberg, Randal I; Beller, George A

2012-04-01

220

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

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

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

2014-01-01

221

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

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

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

2014-01-01

222

Ultralong, small-diameter TiOTiO? nanotubes achieved by an optimized two-step anodization for efficient dye-sensitized solar cells.  

PubMed

An optimized two-step anodization is developed to fabricate ultralong, small-diameter TiO2 nanotubes, that is, with tube length of up to 31 ?m and pore diameter of about 35 nm in this work. This overcomes the length limitation of small diameter tubes that usually presents in conventional one-step anodization. The small tubes with lengths of 23 ?m yield a conversion efficiency of 5.02% in dye-sensitized solar cells under nonoptimized conditions. PMID:24443896

Wang, Xiaoyan; Sun, Lidong; Zhang, Sam; Wang, Xiu

2014-02-12

223

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

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…

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

224

Planting geometry to optimize growth and productivity in faba bean (Vicia faba L.) and soil fertility.  

PubMed

Faba bean (Vicia faba L.) responses to alteration of its ambient environment leads to certain modification in the crop phenology, yield attributes and economic yield. To know the extent and pattern of response by faba bean to alterations, a two year field experimentation was carried out with two crop establishment methods (i) flatbed planting (ii) raised bed planting, four planting geometry (i) 30 x 20 cm(ii) 30 x 30 cm (iii) 30 x 45 cm and (iv) 45X45cm and three seeding depth. All the treatment (two crop establishment methods, four planting geometry and three seeding depth) were combined together consisting twenty four treatments, were organized in factorial experiment in complete randomized block design (CRBD) with three replications. Data were recorded on growth and development; yield attributes and yield. Soil analysis was done and finally statistical tool were applied to come in to valid conclusion. Raised bed planting proves superior over flatbed in case of seed yield. Square planting architect with 30 cm apart prove better (3690.9 kg ha(-1)) than other tested planting geometry. Seeding at 10 cm depth showed, significant improvement in seed yield per plant and per ha over other two tested seeding depth. Phosphorus availability was significantly higher in raised bed planting (36.9 kg ha(-1)). However, available K (kg ha(-1)) was significantly influenced by planting geometry and seeding depth. It was maximum (155.2 kg ha(-1)) with 30 x 45 cm plant geometry, proved significantly higher than 30 x 20 cm and 30 x 30 cm and at par with 45 x 45 cm planting. PMID:24006817

Singh, A K; Bhatt, B P; Sundaram, P K; Gupta, A K; Singh, Deepak

2013-01-01

225

A note on optimal transient growth in turbulent channel flows Gregory Pujals, Manuel Garca-Villalba, Carlo Cossu, and Sebastien Depardon  

E-print Network

A note on optimal transient growth in turbulent channel flows Gregory Pujals, Manuel Garc.1063/1.3258758 Turbulent flow in pipes and channels as cross-stream "inverse cascades" of vorticity Phys. Fluids 20, 125101 of viscoelasticity on the probability density functions in turbulent channel flow Phys. Fluids 21, 115106 (2009); 10

Paris-Sud XI, Université de

226

Optimal conditions for freezing CHO-S and HEK293-EBNA cell lines: influence of Me2SO, freeze density, and PEI-mediated transfection on revitalization and growth of cells, and expression of recombinant protein.  

PubMed

To avoid the time consuming, labor intensive seed-train expansion and to improve production reliability and consistency, portions of bulk cryopreserved cells from the same cultivation can be utilized as inocula or alternatively may be used to undertake transient transfections for large-scale bioreactor production. In this study, the conditions for large-scale freezing in cryobags were optimized utilizing a design of experiment approach. We showed that relatively high density of 30-40 x 10(6) cells/mL and relatively low Me(2)SO concentrations of 5-6% in the freezing media are optimal to freeze HEK293-EBNA and CHO-S cells in a controlled manner in order to achieve high viable cell recovery and growth post-thawing. The immediate transfer of freshly thawed cells into culture medium resulted in better cell growth compared to cells that were centrifuged in order to remove Me(2)SO. This was the case as long as the residual Me(2)SO did not exceed 0.2-0.3%. The best time to perform transient 25 kDa polyethylenimine-mediated transfection of pCEP4-EGFP plasmid into freshly thawed, one-step inoculated cells is after 72-96 h in culture. At this time point, the numbers of EGFP-positive cells in the freshly thawed culture mimic perfectly that of cells grown continuously. Finally, our data showed that it is possible to freeze transiently polyethyleneimine-transfected HEK293-EBNA cells and maintain growth rate and expression of recombinant protein following thawing. The optimal time point for freezing cells was 4 h after transfection. PMID:18351658

Kleman, Marika I; Oellers, Kerstin; Lullau, Elke

2008-08-01

227

High-breakdown-voltage InGaN\\/GaN MQW LED Achieved by Using a Varied-barrier-growth-temperature Method  

Microsoft Academic Search

of the barrier growth temperature of InGaN\\/GaN multi-quantum wells on the breakdown voltage of light emitting diodes. We adopted a two-step varied-barrier-growth temperature method to improve the structural and the electrical properties of the InGaN\\/GaN MQW layers. The depth of the V defect of InGaN\\/GaN MQW surfaces was decreased up to 20 ? A by using a GaN barrier layer

Shi Jong Leem; Young Chul Shin; Eun Hong Kim; Chul Min Kim; Wan Ho Lee; Tae Geun Kim

228

On optimal chemotherapy with a strongly targeted agent for a model of tumor-immune system interactions with generalized logistic growth.  

PubMed

In this paper, a mathematical model for chemotherapy that takes tumor immune-system interactions into account is considered for a strongly targeted agent. We use a classical model originally formulated by Stepanova, but replace exponential tumor growth with a generalised logistic growth model function depending on a parameter v. This growth function interpolates between a Gompertzian model (in the limit v ? 0) and an exponential model (in the limit v ? ?). The dynamics is multi-stable and equilibria and their stability will be investigated depending on the parameter v. Except for small values of v, the system has both an asymptotically stable microscopic (benign) equilibrium point and an asymptotically stable macroscopic (malignant) equilibrium point. The corresponding regions of attraction are separated by the stable manifold of a saddle. The optimal control problem of moving an initial condition that lies in the malignant region into the benign region is formulated and the structure of optimal singular controls is determined. PMID:23906150

Ledzewicz, Urszula; Olumoye, Omeiza; Schättler, Heinz

2013-06-01

229

Production of human lysozyme in biofilm reactor and optimization of growth parameters of Kluyveromyces lactis K7.  

PubMed

Lysozyme (1,4-?-N-acetylmuramidase) is a lytic enzyme, which degrades the bacterial cell wall. Lysozyme has been of interest in medicine, cosmetics, and food industries because of its anti-bactericidal effect. Kluyveromyces lactis K7 is a genetically modified organism that expresses human lysozyme. There is a need to improve the human lysozyme production by K. lactis K7 to make the human lysozyme more affordable. Biofilm reactor provides high biomass by including a solid support, which microorganisms grow around and within. Therefore, the aim of this study was to produce the human lysozyme in biofilm reactor and optimize the growth conditions of K. lactis K7 for the human lysozyme production in biofilm reactor with plastic composite support (PCS). The PCS, which includes polypropylene, soybean hull, soybean flour, bovine albumin, and salts, was selected based on biofilm formation on PCS (CFU/g), human lysozyme production (U/ml), and absorption of lysozyme inside the support. To find the optimum combination of growth parameters, a three-factor Box-Behnken design of response surface method was used. The results suggested that the optimum conditions for biomass and lysozyme productions were different (27 °C, pH 6, 1.33 vvm for biomass production; 25 °C, pH 4, no aeration for lysozyme production). Then, different pH and aeration shift strategies were tested to increase the biomass at the first step and then secrete the lysozyme after the shift. As a result, the lysozyme production amount (141 U/ml) at 25 °C without pH and aeration control was significantly higher than the lysozyme amount at evaluated pH and aeration shift conditions (p?

Ercan, Duygu; Demirci, Ali

2013-07-01

230

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

PubMed

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

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

2008-01-01

231

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

PubMed

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

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

2008-12-01

232

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

PubMed Central

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

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

2014-01-01

233

Large-scale, surfactant-free, hydrothermal synthesis of lithium aluminate nanorods: optimization of parameters and investigation of growth mechanism.  

PubMed

Lithium aluminate nanorods were successfully synthesized from Al2O3 nanoparticles and lithium hydroxide by a simple, large-scale hydrothermal process without any surfactant or template. The various reaction parameters were optimized to achieve the maximum yield. The as-obtained nanorods had orthorhombic beta-lithium aluminate structure with edges in the range of 40-200 nm and lengths of 1-2 mum confirmed by SEM, TEM, XRD, and NMR. Upon calcination at 1273 K for 12 h it transformed to gamma-lithium aluminate, yet maintained the initial morphology, demonstrating the thermal stability. The ratio of lithium hydroxide to aluminum oxide showed a significant effect on the morphology as Li/Al = 1 gives "microroses", whereas Li/Al = 3 and Li/Al = 15 gave "microbricks" and "nanorods", respectively. Investigation of the mechanism showed that the nanorods were formed via a "rolling-up" mechanism. As we used all-inorganic raw materials and a simple synthetic procedure under mild conditions, the scale-up of this process for large-scale production should be very easy. PMID:17371012

Joshi, Upendra A; Lee, Jae Sung

2007-04-16

234

Optimal contrast enhancement achieved by the synthetic method for bone and tissue separation based on a dual-energy radiographic system  

NASA Astrophysics Data System (ADS)

In dual-energy digital radiography (DEDR), the energy subtraction and equivalent thickness methods have been used for detecting thorax lesions. However, the image contrast of the energy subtraction method is low in comparion with that of the equivalent thickness and synthetic methods. Therefore, we applied the equivalent thickness and synthetic methods to material separation to enhance the bone and tissue contrast, and these results were compared with the results of the energy subtraction method in a chest DEDR system. The purpose of this work was to evaluate the image quality of the energy subtraction, equivalent thickness, and synthetic methods. In the energy subtraction method, the optimal weighting factors were selected for bone and tissue visualization, respectively. The equivalent thickness was obtained with a calibration procedure by using combinations of aluminum and polymethyl methacrylate (PMMA) blocks. The synthetic images were acquired with the known equation from the results of the equivalent thickness method. According to these results, the contrast-to-noise-ratio (CNR) values using the equivalent thickness and synthetic methods were improved than those obtained with the energy subtraction method in both aluminum and PMMA enhancement trial. In a cylindrical phantom study, the equivalent thickness and the synthetic method improved the contrast better than energy subtraction method. The synthetic method supplements the air shadows shown in the equivalent thickness method. We compared the enhanced images of bone and tissue with the energy subtraction, equivalent thickness, and synthetic methods. Our results showed that the effects of the synthetic method can improve the image contrast on both bone and tissue and overcome the bone shadows in tissue images in a DEDR system.

Kim, D.-H.; Lee, Y.-J.; Jeon, P.-H.; Jo, B.-D.; Kim, H.-J.

2013-07-01

235

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

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

Lynne F. La Corte

2008-01-01

236

Late Immersion and Language of Instruction (English vs. Chinese) in Hong Kong High Schools: Achievement Growth in Language and Nonlanguage Subjects.  

ERIC Educational Resources Information Center

This study examines how instruction in the first language (L1), Chinese, and in the second language (L2), English, affects a large sample of students' academic achievement in L1, L2, and content, nonlanguage school subjects, including mathematics, science, geography, and history, in their first 3 years of high school. For all four content area…

Hau, Kit-Tai; Marsh, Herbert W.; Kong, Chit-Kwong; Poon, Andrew Chung-Shing

237

Where Have All the Good Men Gone?: An Analysis of Gender Differences in Achievement Growth in Eighth and Ninth Grade Math  

ERIC Educational Resources Information Center

The growing epidemic of male underachievement has spawned a great deal of research in the recent past. This body of research has been inconclusive in determining the causes of the problem. This Capstone Project looked at six factors to determine if any of them had a significant effect on the math achievement of either gender. This study was…

Plue, Kevin Eric

2011-01-01

238

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

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:…

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

2013-01-01

239

Unprecedented current density to high fields in YBa2Cu3O7 - delta superconductor through nano-defects generated by preform optimization in infiltration growth process  

Microsoft Academic Search

We report record high current densities of 230 kA cm - 2 at zero field, and in excess of 10 kA cm - 2 up to 7 T at 77 K, in YBa2Cu3O7 - delta (Y-123) superconductors fabricated by a modified infiltration growth (IG) process. This was accomplished by optimizing the Y2BaCuO5 (Y-211) preform, into which liquid phases were infiltrated,

N. Devendra Kumar; T. Rajasekharan; K. Muraleedharan; A. Banerjee; V. Seshubai

2010-01-01

240

Optimization of Growth Medium and Enzyme Assay Conditions for Crude Cellulases Produced by a Novel Thermophilic and Cellulolytic Bacterium, Anoxybacillus sp. 527  

Microsoft Academic Search

A newly isolated Anoxybacillus sp. 527 was found to grow on crystalline cellulose as sole carbon and energy sources. Cellulases secreted by strain 527 were\\u000a better induced by cellobiose, followed by glucose, lactose, sucrose, and cellulose. Cellulase secretion was enhanced by an\\u000a optimized medium. Cellulase activity was increased by the addition of Ca2+ and NH4+ and achieved maximum as 7.0 FPU

Yanna Liang; Zisong Feng; Jemil Yesuf; James W. Blackburn

2010-01-01

241

Growth of silicon carbide bulk crystals by physical vapor transport method and modeling efforts in the process optimization  

Microsoft Academic Search

Silicon carbide bulk crystals were grown in an induction-heating furnace using the physical vapor transport method. Crystal growth modeling was performed to obtain the required inert gas pressure and temperatures for sufficiently large growth rates. The SiC crystals were expanded by designing a growth chamber having a positive temperature gradient along the growth interface. The obtained 6H-SiC crystals were cut

Qi-Sheng Chen; Jing Lu; Zi-Bing Zhang; Guo-Dan Wei; Vish Prasad

2006-01-01

242

Acta Cryst. (1994). D50, 572-590 Quantitative Analysis in the Characterization and Optimization of Protein Crystal Growth  

E-print Network

of Protein Crystal Growth BY CHARLESW. CARTERJR AND YUHUI YIN Department of Biochemistry and Biophysics 21 October 1993; accepted 31 January 1994) Abstract Protein crystal growth often depends on the combi of biochemical parameters, such as lig- ands and pH. Tests of the reproducibility of crystal growth experiments

Yin, Y. Whitney

243

INTEGR. COMP. BIOL., 44:471479 (2004) Growth Strategies and Optimal Body Size in Temperate Pararginii Butterflies1  

E-print Network

of juvenile growth rates that would allow organisms to become as large as pos- sible in as short time; Gotthard, 2000). For example, most organisms do not maximize their juvenile growth effort and thus, Louisiana. 2 E-mail: Karl.Gotthard@zoologi.su.se untarily'' reduce juvenile growth rates instead of try- ing

Gotthard, Karl

244

Growth hormone in chronic renal disease  

PubMed Central

Severe growth retardation (below the third percentile for height) is seen in up to one-third children with chronic kidney disease. It is thought to be multifactorial and despite optimal medical therapy most children are unable to reach their normal height. Under-nutrition, anemia, vitamin D deficiency with secondary hyperparathyroidism, metabolic acidosis, hyperphosphatemia, renal osteodystrophy; abnormalities in the growth hormone/insulin like growth factor system and sex steroids, all have been implicated in the pathogenesis of growth failure. Therapy includes optimization of nutritional and metabolic abnormalities. Failure to achieve adequate height despite 3–6 months of optimal medical measures mandates the use of recombinant GH (rGH) therapy, which has shown to result in catch-up growth, anywhere from 2 cm to 10 cm with satisfactory liner, somatic and psychological development. PMID:22470855

Gupta, Vishal; Lee, Marilyn

2012-01-01

245

Enhanced heteroepitaxial growth of CoCrPt-SiO{sub 2} perpendicular magnetic recording media on optimized Ru intermediate layers  

SciTech Connect

The crystallographic growth, interfacial roughness, and magnetic properties of CoCrPt-SiO{sub 2} perpendicular magnetic recording media prepared on various types of Ru intermediate growth layers were systematically investigated based on high angle and omega offset x-ray diffraction scans, rocking curve scans, synchrotron radiation based grazing incidence reflectivity scans, and magneto-optical Kerr hysteresis loops. For samples that make use of one Ru growth layer, voltage bias applied on the Ru layer was seen to have two observable effects: (1) the dispersion in the Ru(00{center_dot}2) perpendicular texture increased, but that of the Co(00{center_dot}2) remained unchanged, leading to identical layered growth and (2) the in-plane a-lattice parameter of the Ru decreased leading to enhanced heteroepitaxy with the Co. There was no significant change in the Ru-Co interfacial roughness with changing the bias on the Ru layer. The bias effect can be used to optimize the design of the Ru intermediate layers. A scheme that makes use of two Ru growth layers consisting of a bottom Ru layer prepared under zero bias, which is inserted below a second Ru layer prepared under biased conditions, is shown to lead to significant benefits such as improved texture without affecting the magnetic properties. This is due to the different functional roles ascribed to each of the Ru growth layers.

Srinivasan, Kumar; Piramanayagam, S. N. [Data Storage Institute, A-STAR, 5 Engineering Drive 1, Singapore 117608 (Singapore)

2008-01-15

246

Growth of silicon carbide bulk crystals by physical vapor transport method and modeling efforts in the process optimization  

NASA Astrophysics Data System (ADS)

Silicon carbide bulk crystals were grown in an induction-heating furnace using the physical vapor transport method. Crystal growth modeling was performed to obtain the required inert gas pressure and temperatures for sufficiently large growth rates. The SiC crystals were expanded by designing a growth chamber having a positive temperature gradient along the growth interface. The obtained 6H-SiC crystals were cut into wafers and characterized by Raman scattering spectroscopy and X-ray diffraction, and the results showed that most parts of the crystals had good crystallographic structures.

Chen, Qi-Sheng; Lu, Jing; Zhang, Zi-Bing; Wei, Guo-Dan; Prasad, Vish

2006-07-01

247

Daily energy balance in growth hormone receptor/binding protein (GHR-/-) gene-disrupted mice is achieved through an increase in dark-phase energy efficiency  

PubMed Central

The goal of this study was to examine factors that contribute to energy balance in female GHR ?/? mice. We measured energy intake, energy expenditure (EE), fuel utilization, body mass (Mb) changes and physical activity in 17 month-old female GHR ?/? mice and their age-matched wild type littermates. The GHR ?/? mice were smaller, consumed more food per unit Mb, had greater EE per unit Mb and had an increase in 24-h EE/Mb that was similar to the increase in their surface-area-to-volume ratio. Locomotor activity (LMA) was reduced in the GHR ?/? mice, but the energetic cost associated with their LMA was greater than in wild type controls. Furthermore, Mb and LMA were independent explanatory covariates of most of the variance in EE, and when adjusted for Mb and LMA, the GHR ?/? mice had higher EE during both the light and dark phases of the daily cycle. Respiratory quotient was lower in GHR ?/? mice during the light phase, which indicated a greater utilization of lipid relative to carbohydrate in these mice. Additionally, GHR ?/? mice had higher ratios of caloric intake to EE at several intervals during the dark phase, and this effect was greater and more sustained in the final three hours of the dark phase. Therefore, we conclude that GHR ?/? mice are able to overcome the substantial energetic challenges of dwarfism through several mechanisms that promote stable Mb. Relative to wild type mice, the GHR ?/? mice consumed more calories per unit Mb, which offset the disproportionate increase in their daily energy expenditure. While GHR ?/? mice oxidized a greater proportion of lipid during the light phase in order to meet their energy requirements, they achieved greater energy efficiency and storage during the dark phase through a combination of higher energy consumption and lower LMA. PMID:19747867

Longo, Kenneth A.; Berryman, Darlene E.; Kelder, Bruce; Charoenthongtrakul, Soratree; DiStefano, Peter S.; Geddes, Brad J.; Kopchick, John

2009-01-01

248

Optimization of fermentation medium and conditions for mycelial growth and water-soluble exo-polysaccharides production by Isaria farinosa B05.  

PubMed

The optimal fermentation medium and conditions for mycelial growth and water-soluble exo-polysaccharides production by Isaria farinosa B05 were investigated. The medium components and fermentation conditions were optimized according to the one at a time method, while the concentration of medium components was determined by the orthogonal matrix method. The results showed that the optimal fermentation medium was as follows: sucrose 3.5% (w/v), peptone 0.5%, yeast extract 0.2%, K(2)HPO(4) 0.1%, and MgSO(4) 0.05%. The suitable fermentation conditions were as follows: initial pH 7.0, temperature 25 degrees C, medium volume 75 mL/250 mL, inoculum volume 5% (v/v), time 5d. In such optimal nutrition and environmental conditions, the maximal mycelial yield was 2.124 g/100 mL after 4 day's fermentation, while maximal water-soluble exo-polysaccharides production reached 2.144 g/L after 5 day's fermentation. PMID:18569876

Wang, P; Jiang, X; Jiang, Y; Hu, X; Hwang, H

2008-01-01

249

Preform optimization in infiltration growth process: An efficient method to improve the superconducting properties of YBa2Cu3O7-?  

NASA Astrophysics Data System (ADS)

The effect of compaction pressure applied to the Y2BaCuO5 (Y-211) preform during its fabrication, on the final microstructures and current densities (Jc) is investigated. The necessity for optimizing the sintering conditions in order to provide mechanical stability to the preform prior to the infiltration of liquid phases is demonstrated. The sample fabricated under optimized conditions showed Jc values better than 103 A cm-2 up to applied magnetic fields of 6.5 Tesla at 77 K. The microstructural factors influencing the field dependence of Jc ‘Jc(H)’ at low and high fields are investigated. Extensive nano-twinning with large number of crossing twins observed in the optimized sample and the associated high defect densities are correlated to be the source of flux pinning to high fields. The fact that YBa2Cu3O7-? (YBCO, Y-123) superconductor obtained employing the present Preform Optimized Infiltration and Growth Process (POIGP) yields a homogenous and dense distribution of fine Y-211 particles, that creates suitable twin/defect densities to provide flux pinning at high fields, is of technical importance.

Devendra Kumar, N.; Rajasekharan, T.; Seshubai, V.

2013-12-01

250

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

NASA Astrophysics Data System (ADS)

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.

Srinivasan, V.; Kumar, P.

2012-12-01

251

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

SciTech Connect

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}.

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

252

Effect of Ag addition on the microstructures and superconducting properties of bulk YBCO fabricated by Directionally Solidified Preform Optimized Infiltration Growth Process  

NASA Astrophysics Data System (ADS)

A bulk YBa2Cu3O7-? (YBCO)/Ag superconducting composite with a homogenous distribution of fine and spherical particles of metallic Ag and Y2BaCuO5 (Y-211) has been fabricated by employing Directionally Solidified Preform Optimized Infiltration Growth Process (DS-POIGP). The effect of adding Ag into the liquid phase source (YBa2Cu3O7-?) placed above the Y-211 preform on the microstructures and current densities is investigated. The addition of Ag led to a significant refinement of Y-211 particle size and, hence, enabled the enhancement of current densities at low fields.

Devendra Kumar, N.; Missak Swarup Raju, P.; Pavan Kumar Naik, S.; Rajasekharan, T.; Seshubai, V.

2014-01-01

253

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

E-print Network

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 x 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 ...

Letort, Veronique; Cournède, Paul-Henry; De Reffye, Philippe; Courtois, Brigitte; 10.1093/aob/mcm197

2010-01-01

254

NADH-regulated metabolic model for growth of Methylosinus trichosporium OB3b. Cometabolic degradation of trichloroethene and optimization of bioreactor system performance  

SciTech Connect

A metabolic model describing growth of Methylosinus trichosporium OB3b and cometabolic contaminant conversion is used to optimize trichloroethene (TCE) conversion in a bioreactor system. Different process configurations are compared: a growing culture and a nongrowing culture to which TCE is added at both constant and pulsed levels. The growth part of the model, presented in the preceding article, gives a detailed description of the NADH regeneration required for continued TCE conversion. It is based on the metabolic pathways, includes Michaelis--Menten type enzyme kinetics, and uses NADH as an integrating and controlling factor. Here the model is extended to include TCE transformation, incorporating the kinetics of contaminant conversion, the related NADH consumption, toxic effects, and competitive inhibition between TCE and methane. The model realistically describes the experimentally observed negative effects of the TCE conversion products, both on soluble methane monooxygenase through the explicit incorporation of the activity of this enzyme and on cell viability through the distinction between dividing and nondividing cells. In growth-based systems, the toxicity of the TCE conversion products causes rapid cell death, which leads to wash-out of suspended cultures at low TCE loads. Enzyme activity, which is less sensitive, is hardly affected by the toxicity of the TCE conversion products and ensures high conversions (>95%) up to the point of wash-out. Pulsed addition of TCE leads to a complete loss of viability. However, the remaining enzyme activity can still almost completely covert the subsequently added large TCE pulses. This emphasizes the inefficient use of enzyme activity in growth-based systems. A comparison of growth-based and similar non-growth-based systems reveals that the highest TCE conversions per amount of cells grown can be obtained in the latter. Using small amounts of methane, NADH limitation in the second step of this two-step system can be eliminated. This results in complete utilization of enzyme activity and thus in a very effective treatment system.

Sipkema, E.M.; Koning, W. de; Ganzeveld, K.J.; Janssen, D.B.; Beenackers, A.A.C.M.

2000-04-01

255

Self-Beliefs and Student Goal Achievement  

ERIC Educational Resources Information Center

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…

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

2011-01-01

256

The Future of Optimism  

Microsoft Academic Search

Recent theoretical discussions of optimism as an inherent aspect of human nature converge with empirical investigations of optimism as an individual difference to show that optimism can be a highly beneficial psychological characteristic linked to good mood, perseverance, achievement, and physical health. Questions remain about optimism as a research topic and more generally as a societal value. Is the meaning

Christopher Peterson

2000-01-01

257

Growth + Achievement GW SMHS | Annual Report 2013  

E-print Network

tangible solutions to many of the most complex problems associated with cancer, HIV/AIDS, and neurological facing many medical students after graduation. Through our generous alumni and grateful patient care since the dawn of the 20th century, and faculty leaders at the George Washington University School

Vertes, Akos

258

Omic data from evolved E. coli are consistent with computed optimal growth from genome-scale models  

Microsoft Academic Search

After hundreds of generations of adaptive evolution at exponential growth, Escherichia coli grows as predicted using flux balance analysis (FBA) on genome-scale metabolic models (GEMs). However, it is not known whether the predicted pathway usage in FBA solutions is consistent with gene and protein expression in the wild-type and evolved strains. Here, we report that >98% of active reactions from

Nathan E. Lewis; Kim K. Hixson; Tom M. Conrad; Joshua A. Lerman; Pep Charusanti; Ashoka D. Polpitiya; Joshua N. Adkins; Gunnar Schramm; Samuel O. Purvine; Daniel Lopez-Ferrer; Karl K. Weitz; Roland Eils; Rainer König; Richard D. Smith; Bernhard O. Palsson

2010-01-01

259

Angular distribution of molecular beams and homogeneous layer growth: optimization of geometrical parameters in molecular beam epitaxy  

Microsoft Academic Search

Preceding studies of angular distribution flows issued from molecular beam sources used in molecular beam epitaxy are analysed by comparison with analogous studies as performed on the Knudsen effusion cell method. A new architecture of the effusion sources and substrate relative disposition for epitaxial growth is proposed which discards any re-vaporized parasitic flow of molecules and which is aimed to

Jean-Luc Vassent; Alain Marty; Bruno Gilles; Christian Chatillon

2001-01-01

260

Optimization of gonad growth by manipulation of temperature and photoperiod in cultivated sea urchins, Paracentrotus lividus (Lamarck) (Echinodermata)  

Microsoft Academic Search

A starvation and then feeding method was developed to produce about 100% marketable sea urchins, Paracentrotus lividus, in 3 1\\/2 months. This method is needed because the reproduction cycle is desynchronized in the conditions imposed during the somatic growth stage in land-based closed systems. The major advantages of starving the animals are resetting the reproductive cycle to the spent stage

Christine Spirlet; Philippe Grosjean; Michel Jangoux

2000-01-01

261

Optimization of hydrothermal growth ZnO Nanorods for enhancement of light extraction from GaN blue LEDs  

Microsoft Academic Search

In this study, we report on the enhancement in the light extraction efficiency of GaN blue LEDs topped with ZnO nanorods. The ZnO nanorods were grown by a two-step hydrothermal synthesis with pre-coated ZnO nanoparticles under optimized condition to give the appropriate size and quality, giving an increase in the light output efficiency of 66%. This improvement is attributed to

C. B. Soh; C. B. Tay; S. J. Chua; H. Q. Le; N. S. S. Ang; J. H. Teng

2010-01-01

262

Design and Optimization of Novel Hydroxamate-Based Histone Deacetylase Inhibitors of Bis-Substituted Aromatic Amides Bearing Potent Activities against Tumor Growth and Metastasis.  

PubMed

Histone deacetylases (HDACs) are one of the most promising drug targets for cancer therapy, and since more than 90% of all cancer-related deaths are associated with tumor metastasis, developing strategies to inhibit tumor metastasis while retaining anti-tumor growth activity are of great interest. Herein we demonstrated the design and identification of a series of novel hydroxamate-based HDAC inhibitors bearing potent activities against tumor growth and metastasis. Optimization of the initial hit resulted in the discovery of new HDAC inhibitors through studying the structure-activity relationship. Among them, compound 11b, one of the most potent leads, exhibited nanomolar IC50 values toward inhibition of class I and IIb HDACs as well as sub-micromolar activity against proliferation and migration of breast cancer cells in vitro. More importantly, it also significantly suppressed tumor growth in a breast tumor xenograft mouse model and dose-dependently blocked in vivo tumor metastasis in a mouse pulmonary metastasis model. PMID:25360834

Yang, Feifei; Zhang, Tao; Wu, Haigang; Yang, Yang; Liu, Ning; Chen, Ang; Li, Qiang; Li, Jingjie; Qin, Liwen; Jiang, Beier; Wang, Xin; Pang, Xiufeng; Yi, Zhengfang; Liu, Mingyao; Chen, Yihua

2014-11-26

263

Optimization of printed coil arrays for microscopic imaging and spectroscopy  

Microsoft Academic Search

Nuclear Magnetic Resonance (NMR) microscopic imaging and spectroscopy may prove to be a potential tool for monitoring the development of breast tumors grown in rats. In order to monitor the various stages of the tumor's growth a dedicated RF coil must be designed to achieve a high signal-to-noise ratio (SNR) throughout an appropriate region. This study describes the optimization of

Jennifer R. Spadea; Steven M. Wright

1997-01-01

264

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

USGS Publications Warehouse

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.

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

265

Optimal Control over the InAs Nanowire Growth for System Integration and their Structural and Transport Properties  

Microsoft Academic Search

We present new fundamental insights into the nucleation and evolution of InAs nanowires (NWs) grown using organo-metallic vapor-phase epitaxy (OMVPE), the correlation of their room temperature transport behavior with their structural properties, and a novel scheme for their integration to Si substrates. We experimentally distinguish, for the first time, two NW growth regimes defined by the direction of In adatom

Shadi A. Dayeh; Darija Susac; Peng Chen; Yi Jing; K. L. Kavanagh; S. S. Lau; E. T. Yu; Deli Wang

2008-01-01

266

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

267

A framework for IT performance management Enabling organizational growth with IT performance management  

E-print Network

1 A framework for IT performance management Enabling organizational growth with IT performance The Netherlands #12;3 A framework for IT performance management Enabling organizational growth with IT performance organizations can achieve and optimize the benefits of IT performance management. The relevance of this research

Utrecht, Universiteit

268

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

269

Optimization of some growth process parameters of an Nd:YAG cylindrical bar grown in a vacuum by edge-defined film-fed growth method  

NASA Astrophysics Data System (ADS)

The main purpose of this paper is to find those values of the die radius r0, pulling rate v and melt temperature T0 at the meniscus basis which assures the growth of an Nd:YAG cylindrical bar with a prescribed diameter 2 rf for which the nonuniformities of the surface of the bar, due to small uncontrollable oscillations of v and T0 are minimum possible. Numerical results are given for an Nd:YAG cylindrical bar of 5 mm diameter, grown in a furnace in which the vertical temperature gradient is k=33 K/mm. For a value of v in the range v? 0.0001,0.53 mm/s and a value of T0 in the range T 0? 2244,3000 , four types of uncontrollable oscillations Oi, i= overline1,4, of these parameters are considered: O1= (? v=±0.001 mm/s and ? T=±1 K), O2= (? v=±0.01 mm/s and ? T=±10 K), O3= (? v=±0.02 mm/s and ? T=±20 K), O4= (? v=±0.001 mm/s and ? T=±30 K). For a set of six values of r0 in the range r 0? 2.6,4.0 mm, the amplitude of the crystal radius variation due to the above four oscillations is computed. It is found that the amplitude of the crystal radius variation due to the considered oscillations is minimum for r0=2.6mm, v=0.0119mm/s, T0=2305K for O1; r0=2.6mm, v=0.0243mm/s, T0=2303K for O2; r0=2.6mm, v=0.0466mm/s, T0=2299K for O3; r0=2.7mm, v=0.0011mm/s, T0=2360K for O4.

Braescu, L.; Balint, A. M.; Balint, St.

2004-07-01

270

Optimization of Ligninolytic Enzyme Activity and Production Rate with Ceriporiopsis subvermispora for Application in Bioremediation by Varying Submerged Media Composition and Growth Immobilization Support  

PubMed Central

Response surface methodology (central composite design of experiments) was employed to simultaneously optimize enzyme production and productivities of two ligninolytic enzymes produced by Ceriporiopsis subvermispora. Concentrations of glucose, ammonium tartrate and Polysorbate 80 were varied to establish the optimal composition of liquid media (OLM), where the highest experimentally obtained activities and productivities were 41 U L?1 and 16 U L?1 day?1 for laccase (Lac), and 193 U L?1 and 80 U L?1 day?1 for manganese peroxidase (MnP). Considering culture growth in OLM on various types of immobilization support, the best results were obtained with 1 cm beech wood cubes (BWCM). Enzyme activities in culture filtrate were 152 U L?1 for Lac and 58 U L?1 for MnP, since the chemical composition of this immobilization material induced higher Lac activity. Lower enzyme activities were obtained with polyurethane foam. Culture filtrates of OLM and BWCM were applied for dye decolorization. Remazol Brilliant Blue R (RBBR) was decolorized faster and more efficiently than Copper(II)phthalocyanine (CuP) with BWCM (80% and 60%), since Lac played a crucial role. Decolorization of CuP was initially faster than that of RBBR, due to higher MnP activities in OLM. The extent of decolorization after 14 h was 60% for both dyes. PMID:23109859

Babic, Janja; Likozar, Blaz; Pavko, Aleksander

2012-01-01

271

Unprecedented current density to high fields in YBa2Cu3O7 - ? superconductor through nano-defects generated by preform optimization in infiltration growth process  

NASA Astrophysics Data System (ADS)

We report record high current densities of 230 kA cm - 2 at zero field, and in excess of 10 kA cm - 2 up to 7 T at 77 K, in YBa2Cu3O7 - ? (Y-123) superconductors fabricated by a modified infiltration growth (IG) process. This was accomplished by optimizing the Y2BaCuO5 (Y-211) preform, into which liquid phases were infiltrated, through a combination of high pressure compaction and limiting the sintering temperature. The optimized sample yielded a Y-123 superconductor with a uniform distribution of fine-grained Y-211. Strong and almost invariant flux pinning observed to high fields up to 7 T, suggest a temperature independent flux pinning mechanism originating from defects in the size range 15-50 nm. Since the present sample has no added grain refiners, nano-sized dopants or mixed rare earths leading to low Tc solid solutions, a unique opportunity presents itself to investigate the cause of the enhanced flux pinning to high fields. We have therefore investigated our samples by transmission electron microscopy, and the studies revealed the presence of domains in the sample with nano-sized defects starting from the domain boundaries, as a possible source of enhanced flux pinning.

Devendra Kumar, N.; Rajasekharan, T.; Muraleedharan, K.; Banerjee, A.; Seshubai, V.

2010-10-01

272

Multiple long-term, experimentally-evolved populations of Escherichia coli acquire dependence upon citrate as an iron chelator for optimal growth on glucose  

PubMed Central

Background Specialization for ecological niches is a balance of evolutionary adaptation and its accompanying tradeoffs. Here we focus on the Lenski Long-Term Evolution Experiment, which has maintained cultures of Escherichia coli in the same defined seasonal environment for 50,000 generations. Over this time, much adaptation and specialization to the environment has occurred. The presence of citrate in the growth media selected one lineage to gain the novel ability to utilize citrate as a carbon source after 31,000 generations. Here we test whether other strains have specialized to rely on citrate after 50,000 generations. Results We show that in addition to the citrate-catabolizing strain, three other lineages evolving in parallel have acquired a dependence on citrate for optimal growth on glucose. None of these strains were stimulated indirectly by the sodium present in disodium citrate, nor exhibited even partial utilization of citrate as a carbon source. Instead, all three of these citrate-stimulated populations appear to rely on it as a chelator of iron. Conclusions The strains we examine here have evolved specialization to their environment through apparent loss of function. Our results are most consistent with the accumulation of mutations in iron transport genes that were obviated by abundant citrate. The results present another example where a subtle decision in the design of an evolution experiment led to unexpected evolutionary outcomes. PMID:22909317

2012-01-01

273

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

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%.

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

274

Optimization of cultural conditions for growth associated chromate reduction by Arthrobacter sp. SUK 1201 isolated from chromite mine overburden.  

PubMed

Arthrobacter sp. SUK 1201, a chromium resistant and reducing bacterium having 99% sequence homology of 16S rDNA with Arthrobacter sp. GZK-1 was isolated from chromite mine overburden dumps of Orissa, India. The objective of the present study was to optimize the cultural conditions for chromate reduction by Arthrobacter sp. SUK 1201. The strain showed 67% reduction of 2mM chromate in 7 days and was associated with the formation of green insoluble precipitate, which showed characteristic peak of chromium in to energy dispersive X-ray analysis. However, Fourier transform infrared spectra have failed to detect any complexation of end products of Cr(VI) reduction with the cell mass. Reduction of chromate increased with increased cell density and was maximum at 10(10)cells/ml, but the reduction potential decreased with increase in Cr(VI) concentration. Chromate reducing efficiency was promoted when glycerol and glucose was used as electron donors. Optimum pH and temperature of Cr(VI) reduction was 7.0 and 35 °C respectively. The reduction process was inhibited by several metal ions and metabolic inhibitors but not by Cu(II) and DNP. These findings suggest that Arthrobacter sp. SUK 1201 has great promise for use in Cr(VI) detoxification under a wide range of environmental conditions. PMID:22361630

Dey, Satarupa; Paul, A K

2012-04-30

275

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

PubMed Central

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

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

1997-01-01

276

Uracil content of 16S rRNA of thermophilic and psychrophilic prokaryotes correlates inversely with their optimal growth temperatures.  

PubMed

We report here the finding of a highly significant inverse correlation of the uracil content of 16S rRNA and the optimum growth temperature (T(opt)) of cultured thermophilic and psychrophilic prokaryotes. This correlation was significantly different from the weaker correlations between the contents of other nucleotides and T(opt). Analysis of the 16S rRNA secondary structure regions revealed a fall in the A:U base-pair content in step with the increase in T(opt) that was much steeper than that of mismatched base-pairs, which are thermodynamically less stable. These findings indicate that the 16S rRNA sequences of thermophiles and psychrophiles are under a strong thermo-adaptive pressure, and that structure-function constraints play a crucial role in determining their 16S rRNA nucleotide composition. The derived relationship between uracil content and T(opt) was used to develop an algorithm to predict the T(opt) values of uncultured prokaryotes lacking cultured close relatives and belonging to the phyla predominantly containing thermophiles. This algorithm may be useful in guiding the design of cultivation conditions for hitherto uncultured microbes. PMID:16030352

Khachane, Amit N; Timmis, Kenneth N; dos Santos, Vítor A P Martins

2005-01-01

277

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

PubMed

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?

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

2014-03-01

278

Seed Layer Dependence of ZnO Nanorod Growth  

Microsoft Academic Search

ZnO is a wide band gap semiconductor for optoelectronic applications such as solar cells, transparent conducting electrodes, and chemicals sensors. In past decades, significant progress has been achieved in controlled growth of ZnO nanorods and nanotubes. In this study we investigate the optimization of the growth properties such as orientation, diameter and shape of ZnO nanorods grown by a low

Daryl Spencer; Amy Hor; Huan Liang; Parameswar Hari

2010-01-01

279

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

PubMed Central

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

Perez, Natalie Marie; Ramakrishnan, Girija

2014-01-01

280

Comparing Science Achievement Constructs: Targeted and Achieved  

ERIC Educational Resources Information Center

This article illustrates how test specifications based solely on academic content standards, without attention to other cognitive skills and item response demands, can fall short of their targeted constructs. First, the authors inductively describe the science achievement construct represented by a statewide sixth-grade science proficiency test.…

Ferrara, Steve; Duncan, Teresa

2011-01-01

281

Measuring Student Achievement.  

ERIC Educational Resources Information Center

This report provides background on statewide student testing and testing alternatives in Ohio. The status of achievement testing in other states is also discussed. Educational testing historically has included the two strands of intelligence testing and achievement testing. This report focuses on achievement testing. The two basic forms are…

Ohio State Legislative Office of Education Oversight, Columbus.

282

Optimal growth conditions for GdBa 2Cu 3O 7 thin-film coated conductors characterized by polarized Raman scattering spectroscopy  

NASA Astrophysics Data System (ADS)

High temperature superconducting GdBa 2Cu 3O 7 (GdBCO) thin films were grown by pulsed laser ablation. Textured MgO on metal substrates was used as a template for second generation wire applications. Growth conditions of GdBCO thin films were investigated for substrate temperature ( T s) and oxygen partial pressure (PO 2) during deposition. Superconducting critical currents of the films were obtained in the films grown at 790-810 °C of T s and at 100-700 mTorr of PO 2. Scanning electron micrographs of the films revealed uniform and well-connected grains with some outgrown structures. X-ray ?-2 ? scans of the films grown at 810 °C and 300-500 mTorr exhibited c-axis oriented texture. In-plane alignment and c-axis mosaic spread of the films were determined from X-ray ? scans and rocking curves, respectively. Polarized Raman scattering spectroscopy was used to characterize optical phonon modes, oxygen content, cation disorder, and some possible second phases of the films. The Raman spectra of the films with large critical current density showed modes at 326-329 cm -1, 444-447 cm -1, 500-503 cm -1 related to vibration of oxygen atoms. Origin of small peaks near 600 cm -1 will be discussed as well. The information obtained from Raman scattering measurements will be useful for quality control of the conductors as well as optimization of the process conditions.

Kim, G.; Jeong, A. R.; Jo, W.; Park, D. Y.; Cheong, H.; Shin, G. M.; Yoo, S. I.

2010-11-01

283

Prospective Optimization  

PubMed Central

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

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

2014-01-01

284

A new optimization based approach to experimental combination chemotherapy.  

PubMed

A new approach towards the design of optimal multiple drug experimental cancer chemotherapy is presented. Once an adequate model is specified, an optimization procedure is used in order to achieve an optimal compromise between after treatment tumor size and toxic effects on healthy tissues. In our approach we consider a model including cancer cell population growth and pharmacokinetic dynamics. These elements of the model are essential in order to allow less empirical relationships between multiple drug delivery policies, and their effects on cancer and normal cells. The desired multiple drug dosage schedule is computed by minimizing a customizable cost function subject to dynamic constraints expressed by the model. However, this additional dynamic wealth increases the complexity of the problem which, in general, cannot be solved in a closed form. Therefore, we propose an iterative optimization algorithm of the projected gradient type where the Maximum Principle of Pontryagin is used to select the optimal control policy. PMID:7612501

Pereira, F L; Pedreira, C E; de Sousa, J B

1995-01-01

285

Achieving real-time performance in FIESTA  

NASA Technical Reports Server (NTRS)

The Fault Isolation Expert System for TDRSS Applications (FIESTA) is targeted for operation in a real-time online environment. Initial stages of the prototype development concentrated on acquisition and representation of the knowledge necessary to isolate faults in the TDRSS Network. Recent efforts focused on achieving real-time performance including: a discussion of the meaning of FIESTA real-time requirements, determination of performance levels (benchmarking) and techniques for optimization. Optimization techniques presented include redesign of critical relations, filtering of redundant data and optimization of patterns used in rules. Results are summarized.

Wilkinson, William; Happell, Nadine; Miksell, Steve; Quillin, Robert; Carlisle, Candace

1988-01-01

286

General Achievement Trends: Connecticut  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

287

General Achievement Trends: Pennsylvania  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

288

General Achievement Trends: Montana  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

289

General Achievement Trends: Massachusetts  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

290

General Achievement Trends: Michigan  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

291

General Achievement Trends: Maryland  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

292

General Achievement Trends: Arizona  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

293

General Achievement Trends: Alabama  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

294

General Achievement Trends: Kansas  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

295

General Achievement Trends: Idaho  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

296

General Achievement Trends: Virginia  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

297

General Achievement Trends: Louisiana  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

298

General Achievement Trends: Ohio  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

299

Music and Achievement.  

ERIC Educational Resources Information Center

Discusses a study of the effects of music listening upon student achievement. Reports that seventh grade students listened to music while independently studying the earth-sun relationship. Concludes that there were no significant achievement differences among students who learned while listening to rock, classical, easy listening, or no music. (SG)

Smith, Ben A.; Davidson, Charles W.

1991-01-01

300

Confronting the Achievement Gap  

ERIC Educational Resources Information Center

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…

Gardner, David

2007-01-01

301

Achieving Public Schools  

ERIC Educational Resources Information Center

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…

Abowitz, Kathleen Knight

2011-01-01

302

Profiling High Numeracy Achievement  

ERIC Educational Resources Information Center

Profiling high numeracy achievement is the South Australian Department of Education and Children's Services component of the Australian Government funded Strategic Numeracy Research and Development Initiative. This article presents the Profiling High Numeracy Achievement Project Team report on the South Australian Department of Education and…

Australian Primary Mathematics Classroom, 2004

2004-01-01

303

General Achievement Trends: Nebraska  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

304

Current sports club Achievements  

E-print Network

. Performance goals for the next academic year Please express as selections, rankings, medals or equilavent email address Will you be entering your first year? Yes No Section 2 Academic details Section 3 SportCurrent sports club Achievements Please list highest sporting achievements over the last 2 years

Reading, University of

305

Mathematics Achievement Scale Score  

E-print Network

417 TIMSS 2011 Mathematics Achievement Fourth Grade #12;TIMSS 2011 Science Achievement Country Average, Canada 528 Quebec, Canada 516 Dubai, UAE 461 Abu Dhabi, UAE 411 Fourth Grade #12;TIMSS 2011 Mathematics Grade Participants Botswana 419 Honduras 396 Yemen 348 Benchmarking Participants North Carolina, US 554

Huang, Jianyu

306

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

E-print Network

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

Mountziaris, T. J.

307

Gear optimization  

NASA Technical Reports Server (NTRS)

The use of formal numerical optimization methods for the design of gears is investigated. To achieve this, computer codes were developed for the analysis of spur gears and spiral bevel gears. These codes calculate the life, dynamic load, bending strength, surface durability, gear weight and size, and various geometric parameters. It is necessary to calculate all such important responses because they all represent competing requirements in the design process. The codes developed here were written in subroutine form and coupled to the COPES/ADS general purpose optimization program. This code allows the user to define the optimization problem at the time of program execution. Typical design variables include face width, number of teeth and diametral pitch. The user is free to choose any calculated response as the design objective to minimize or maximize and may impose lower and upper bounds on any calculated responses. Typical examples include life maximization with limits on dynamic load, stress, weight, etc. or minimization of weight subject to limits on life, dynamic load, etc. The research codes were written in modular form for easy expansion and so that they could be combined to create a multiple reduction optimization capability in future.

Vanderplaats, G. N.; Chen, Xiang; Zhang, Ning-Tian

1988-01-01

308

Controlled growth of Zn-polar ZnO epitaxial film by nitridation of sapphire substrate  

NASA Astrophysics Data System (ADS)

Surface nitridation is used to eliminate O-polar inversion domains and control the growth of single-domain Zn-polar ZnO film on sapphire (0001) substrate by rf-plasma-assisted molecular-beam epitaxy. It is found that the nitridation temperature is crucial for achieving quality AlN buffer layers and ZnO films with cation polarity, as demonstrated by ex situ transmission electron microscopy. Under optimal growth conditions, a 4×4 surface reconstruction was observed, which is confirmed to be a characteristic surface structure of the Zn-polar films, and can be used as a fingerprint to optimize the ZnO growth.

Mei, Z. X.; Du, X. L.; Wang, Y.; Ying, M. J.; Zeng, Z. Q.; Zheng, H.; Jia, J. F.; Xue, Q. K.; Zhang, Z.

2005-03-01

309

Entropy production of a steady-growth cell with catalytic reactions  

NASA Astrophysics Data System (ADS)

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.

Himeoka, Yusuke; Kaneko, Kunihiko

2014-10-01

310

Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

311

Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors  

NASA Technical Reports Server (NTRS)

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.

Cassell, Alan M.; Meyyappan, M.

2004-01-01

312

Achievability for telerobotic systems  

NASA Astrophysics Data System (ADS)

Methods are needed to improve the capabilities of autonomous robots to perform tasks that are difficult for contemporary robots, and to identify those tasks that robots cannot perform. Additionally, in the realm of remote handling, methods are needed to assess which tasks and/or subtasks are candidates for automation. We are developing a new approach to understanding the capability of autonomous robotic systems. This approach uses formalized methods for determining the achievability of tasks for robots, that is, the likelihood that an autonomous robot or telerobot can successfully complete a particular task. Any autonomous system may be represented in achievability space by the volume describing that system's capabilities within the 3-axis space delineated by perception, cognition, and action. This volume may be thought of as a probability density with achievability decreasing as the distance from the centroid of the volume increases. Similarly, any task may be represented within achievability space. However, as tasks have more finite requirements for perception, cognition, and action, each may be represented as a point (or, more accurately, as a small sphere) within achievability space. Analysis of achievability can serve to identify, a priori, the survivability of robotic systems and the likelihood of mission success; it can be used to plan a mission or portions of a mission; it can be used to modify a mission plan to accommodate unpredicted occurrences; it can also serve to identify needs for modifications to robotic systems or tasks to improve achievability. .

Kress, Reid L.; Draper, John V.; Hamel, William R.

2001-02-01

313

Achievement goals and emotions.  

PubMed

The present investigation examined the influence of three antecedents (fear of failure, personal standards, and concern over mistakes) on achievement goals and also the influence of achievement goals on two affective outcomes (enjoyment and hope). Participants were 204 tennis players from Mexico. Structural Equation Modeling (SEM) was used to analyze the results. We found support for the role of fear of failure, personal standards, and concern over mistakes as antecedents of some achievement goals. Whereas mastery-approach had a significant influence on enjoyment and hope, performance-approach goals had a significant influence on hope only. The implications of the results are discussed. PMID:23705292

Puente-Díaz, Rogelio

2013-01-01

314

Television and Reading Achievement.  

ERIC Educational Resources Information Center

Reports on a survey of 78 seventh-grade students, conducted to investigate the relationship between television viewing and reading achievement. Notes that good readers' viewing habits were not significantly different from those of poor readers. (JT)

Moldenhauer, Deborah L.; Miller, Wilma H.

1980-01-01

315

2013 update Achieving Excellence  

E-print Network

to the approaches to urban planting developed at Sheffield. Olympic fields of dreams Achieving Excellence Excellence-of-the- art, ground-based solar telescope (Swedish 1-m Solar Telescope) with a new solar space telescope (NASA

Martin, Stephen John

316

science and achievements  

E-print Network

-generation power. The Consortium for Advanced Simulation of Light Water Reactors will leverage the Laboratory grant for "Design of the Near Detectors and Optimization of Water and Ice Targets for Fine- grained Tracking Detectors for the Fermilab Long- Baseline Neutrino Experiment." Laboratory Fellow Rusty Gray named

317

Achieving yield gains in wheat.  

PubMed

Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks. PMID:22860982

Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

2012-10-01

318

Indivisible. Good Schools=Health Economy. Poor Academic Achievement=Increased Unemployment. A Longitudinal Pilot Study on the Relationship between Job Growth and School Performance in 15 of Illinois' Largest Counties. A Report to Cook County Assessor Thomas Hynes.  

ERIC Educational Resources Information Center

This longitudinal study indicates that educational reform and economic performance are indivisible. The first part of the study examines job growth or decline by type of job between 1972 and 1985 by county and ranks the counties based on their performance during the 13-year period. The second part of the study examines the relationship between the…

Kyle, Charles L.; Sufritz, Erica

319

CEBAF accelerator achievements  

SciTech Connect

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.

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

2011-06-01

320

CRCHD - SPN Program Achievements  

Cancer.gov

The most significant achievement of the SPN Program is the establishment of a follow-on program - the Community Networks Program for another 5 years at a commitment of $95 million. With 25 grantees, the CNP is building on the accomplishments of the SPN to reduce cancer health disparities at the community level.

321

SALT and Spelling Achievement.  

ERIC Educational Resources Information Center

A study investigated the effects of suggestopedic accelerative learning and teaching (SALT) on the spelling achievement, attitudes toward school, and memory skills of fourth-grade students. Subjects were 20 male and 28 female students from two self-contained classrooms at Kennedy Elementary School in Rexburg, Idaho. The control classroom and the…

Nelson, Joan

322

The creative achievement scale  

Microsoft Academic Search

The Creative Achievement Scale (CAS) was designed to measure the creative accomplishments of deceased individuals based on information extracted from biographical sources (e.g., published biographies). The CAS contains 11 items which pertain to personal attributes, product qualities, and sociocultural factors. Statistical analyses conducted on one small (n = 12) and one larger sample (n = 50) of subjects revealed the

Arnold M. Ludwig

1992-01-01

323

Iowa Women of Achievement.  

ERIC Educational Resources Information Center

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,…

Ohrn, Deborah Gore, Ed.

1993-01-01

324

The Achievement Club  

ERIC Educational Resources Information Center

When Gabrielle Carpenter became a guidance counselor in Northern Virginia nine years ago, she focused on the academic achievement gap and furiously tried to close it. At first, she was compelled by tremendous professional interest. However, after seeing her son lose his zeal for school, Carpenter joined forces with other parents to form an…

Rogers, Ibram

2009-01-01

325

Explorations in achievement motivation  

NASA Technical Reports Server (NTRS)

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.

Helmreich, Robert L.

1982-01-01

326

Achieving All Our Ambitions  

ERIC Educational Resources Information Center

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…

Hartley, Tricia

2009-01-01

327

Issues in Achievement Testing.  

ERIC Educational Resources Information Center

This booklet is intended to help school personnel, parents, students, and members of the community understand concepts and research relating to achievement testing in public schools. The paper's sections include: (1) test use with direct effects on students (test of certification, selection, and placement); (2) test use with indirect effects on…

Baker, Eva L.

328

Achieving Sustainability Cindy Carlsson  

E-print Network

Achieving Sustainability at MnDOT Cindy Carlsson MnDOT Office of Policy Analysis, Research and Innovation 22nd Annual Transportation Research Conference May 24, 2011 #12;Sustainable practices respect Sustainability #12;Environmental Sustainability Sustainable practices · Are compatible with and may enhance

Minnesota, University of

329

Achieving Sustainability Cindy Carlsson  

E-print Network

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

Minnesota, University of

330

Student motivation and achievement  

Microsoft Academic Search

Recent work on student learning has identified three main dimensions of study strategy—personal meaning, reproducing, achieving. University teachers commonly favour the first, deplore the second and tolerate the third. This paper argues that teachers can and should use definite teaching strategies available to them which will enable students to use all three study strategies in support of each other and

Lewis Elton

1988-01-01

331

Academic Achievement and Nongradedness  

ERIC Educational Resources Information Center

A study designed to compare the academic achievement of pupils in graded and non-graded schools using an Index of Non-gradedness to determine the validity of the term non-graded" as applied to some schools. (Author/RY)

Engel, Barney M.; Cooper, Martin

1971-01-01

332

Increasing Male Academic Achievement  

Microsoft Academic Search

The No Child Left Behind legislation has brought greater attention to the academic performance of American youth. Its emphasis on student achievement requires a closer analysis of assessment data by school districts. To address the findings, educators must seek strategies to remedy failing results. In a mid-Atlantic district of the Unites States, the failing of male students was manifested on

Barbara Talbert Jackson

333

Achieving Peace through Education.  

ERIC Educational Resources Information Center

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…

Clarken, Rodney H.

334

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

ERIC Educational Resources Information Center

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…

McCabe, Molly

2010-01-01

335

Growth following solid organ transplantation in childhood  

PubMed Central

One of the ultimate goals of successful solid organ transplantation in pediatric recipients is attaining an optimal final adult height. This manuscript will discuss growth following transplantation in pediatric recipients of kidney, liver, heart, lung or small bowel transplants. Remarkably similar factors impact growth in all of these recipients. Age is a primary factor, with younger recipients exhibiting the greatest immediate catch-up growth. Graft function is a significant contributing factor, with a reduced glomerular filtration rate correlating with poor growth in kidney recipients and the need for re-transplantation with impaired growth in liver recipients. The known adverse impact of steroids on growth has led to modification of the steroid dose and even steroid withdrawal and avoidance. In kidney and liver recipients, this strategy has been associated with the development of acute rejection. In infant heart transplantation, avoiding maintenance corticosteroid immunosuppression is associated with normal growth velocity in the majority of patients. With marked improvements in patient and graft survival rates in pediatric organ recipients, quality of life issues, such as normal adult height, should now receive paramount attention. In general, normal growth following solid organ transplantation should be an achievable goal that results in normal adult height. PMID:24860852

Fine, Richard N.

2014-01-01

336

On the mechanism of optimal disturbances: The role of a pair of nearly parallel modes  

NASA Astrophysics Data System (ADS)

In the present work the role of a pair of nearly parallel least stable modes (having opposite phases and almost identical amplitude distributions), as a key element of optimal transient growth in shear flows, is explored. The general character of this mechanism is demonstrated by four examples. The first two examples are the temporal and spatial growth of optimal disturbances in circular pipe flow. The time and distance, at which the maximum energy amplification of an initial disturbance is achieved, are well predicted analytically by considering only the pair of least stable modes. Furthermore, the dependence of the maximum energy amplification on the Reynolds number matches previous numerical results based on the analysis of many modes. In the temporal case the predicted amplification factor agrees well with these numerical results. The other two examples are concerned with a two-dimensional potential shear layer over a compliant surface, and with a two-dimensional wall-jet. In these examples, a similar growth mechanism takes place near a point where two kinds of two-dimensional modes bifurcate. In the potential shear layer, the maximum optimal growth achieved by two nearly parallel modes is solved analytically for temporal disturbances, whereas in the wall-jet case the distance, at which the maximum amplification is achieved, is well predicted for spatial disturbances. Finally, it appears that the transient growth mechanism based on the interference between two nearly parallel modes is a general case which includes the direct resonance mechanism as a limit for short times.

Ben-Dov, Guy; Levinski, Vladimir; Cohen, Jacob

2003-07-01

337

Project ACHIEVE final report  

SciTech Connect

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.

NONE

1997-06-13

338

Cannabis and educational achievement  

Microsoft Academic Search

Aims To examine the relationship between cannabis use in adolescence\\/young adulthood and levels of educational attainment. Design Data were gathered over the course of a 25-year longitudinal study of a birth cohort of 1265 New Zealand children. Measurements Measures analysed included (a) frequency of cannabis use in adolescence and young adulthood (15-25 years); (b) levels of educational achievement to age

David M. Fergusson; L. John Horwood; Annette L. Beautrais

2003-01-01

339

Achievement Goals and Achievement Emotions: A Meta-Analysis  

ERIC Educational Resources Information Center

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

Huang, Chiungjung

2011-01-01

340

Model based optimization of high cell density cultivation of nitrogen-fixing cyanobacteria.  

PubMed

In the present study, fed-batch cultivation of Cyanothece sp. ATCC 51142, a known hydrogen producer, was optimized for maximizing biomass production. Decline in growth of this organism in dense cultures was attributed to increased substrate consumption for maintenance and respiration, and photolimitation due to self shading. A model incorporating these aspects was developed, and by using control vector parameterization (CVP), substrate feeding recipe was optimized to achieve 12-fold higher biomass concentration. The optimization results were verified experimentally on shake flask and bioreactor. The latter resulted in greater exponential growth rate possibly by overcoming photolimitation by simulating flashing light effect. Such a strategy can be readily applied for mixotrophic cultivation of cyanobacterial cultures in the first stage followed by photoautotrophic growth at the production stage. PMID:24047683

Alagesan, Swathi; Gaudana, Sandeep B; Krishnakumar, S; Wangikar, Pramod P

2013-11-01

341

In situ growth of NiCo2S4 nanotube arrays on Ni foam for supercapacitors: Maximizing utilization efficiency at high mass loading to achieve ultrahigh areal pseudocapacitance  

NASA Astrophysics Data System (ADS)

Self-standing NiCo2S4 nanotube arrays have been in situ grown on Ni foam by the anion-exchange reaction and directly used as the electrode for supercapacitors. The NiCo2S4 nanotube in the arrays effectively reduces the inactive material and increases the electroactive surface area because of the ultrathin wall, which is quite competent to achieve high utilization efficiency at high electroactive materials mass loading. The NiCo2S4 nanotube arrays hybrid electrode exhibits an ultrahigh specific capacitance of 14.39 F cm-2 at 5 mA cm-2 with excellent rate performance (67.7% retention for current increases 30 times) and cycling stability (92% retention after 5000 cycles) at a high mass loading of 6 mg cm-2. High areal capacitance (4.68 F cm-2 at 10 mA cm-2), high energy density (31.5 Wh kg-1 at 156.6 W kg-1) and high power density (2348.5 W kg-1 at 16.6 Wh kg-1) can be achieved by assembling asymmetric supercapacitor with reduced graphene oxide at a total active material mass loading as high as 49.5 mg. This work demonstrates that NiCo2S4 nanotube arrays structure is a superior electroactive material for high-performance supercapacitors even at a mass loading of potential application-specific scale.

Chen, Haichao; Jiang, Jianjun; Zhang, Li; Xia, Dandan; Zhao, Yuandong; Guo, Danqing; Qi, Tong; Wan, Houzhao

2014-05-01

342

Achieve.org  

NSDL National Science Digital Library

These days, a number of individuals are making sure that the nationâÂÂs young people are not left behind, and in addition, a number of organizations have been passionately involved in these efforts as well. One such group is Achieve, which was founded in 1996 by the nationsâ governors and business leaders. As their website notes, âÂÂAchieve serves as a significant national voice for quality in standards-based education reform.â Most visitors will want to start out by taking a look at the âÂÂHow Does Your State Stack Up?â feature. Here visitors can see how their stateâÂÂs high school policies measure up with the demands of college and work, and also how well students in each state are progressing through the educational system in general. The site also offers access to âÂÂPerspectiveâÂÂ, AchieveâÂÂs monthly e-newsletter which covers such topics as college readiness and post-college job expectations. Overall, this is a most useful site for both persons interested in the overall state of education in the United States as well as policy makers in this field.

343

Expert system for controlling plant growth in a contained environment  

NASA Technical Reports Server (NTRS)

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".

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

2011-01-01

344

Expert system for controlling plant growth in a contained environment  

NASA Technical Reports Server (NTRS)

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''.

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

2009-01-01

345

On Constructing the Minimal Seed of Turbulence: Nonlinear Transient Growth  

E-print Network

Linear transient growth analysis is commonly used to suggest the structure of disturbances which are particularly efficient in triggering transition to turbulence in shear flows. We demonstrate that the addition of nonlinearity to the analysis can substantially change the prediction made in pipe flow from simple 2 dimensional streamwise rolls to a spanwise and cross-stream localised 3 dimensional state. This new nonlinear optimal is demonstrably more efficient in triggering turbulence than the linear optimal indicating that there are better ways to design perturbations to achieve transition.

Pringle, Chris C T

2010-01-01

346

Achieving closure at Fernald  

SciTech Connect

When Fluor Fernald took over the management of the Fernald Environmental Management Project in 1992, the estimated closure date of the site was more than 25 years into the future. Fluor Fernald, in conjunction with DOE-Fernald, introduced the Accelerated Cleanup Plan, which was designed to substantially shorten that schedule and save taxpayers more than $3 billion. The management of Fluor Fernald believes there are three fundamental concerns that must be addressed by any contractor hoping to achieve closure of a site within the DOE complex. They are relationship management, resource management and contract management. Relationship management refers to the interaction between the site and local residents, regulators, union leadership, the workforce at large, the media, and any other interested stakeholder groups. Resource management is of course related to the effective administration of the site knowledge base and the skills of the workforce, the attraction and retention of qualified a nd competent technical personnel, and the best recognition and use of appropriate new technologies. Perhaps most importantly, resource management must also include a plan for survival in a flat-funding environment. Lastly, creative and disciplined contract management will be essential to effecting the closure of any DOE site. Fluor Fernald, together with DOE-Fernald, is breaking new ground in the closure arena, and ''business as usual'' has become a thing of the past. How Fluor Fernald has managed its work at the site over the last eight years, and how it will manage the new site closure contract in the future, will be an integral part of achieving successful closure at Fernald.

Bradburne, John; Patton, Tisha C.

2001-02-25

347

Optimal Carbon Capture and Storage policies  

E-print Network

Following the IPCC's report (2005), which recommended the development and the use of carbon capture and sequestration (CCS) technologies in order to achieve the environmental goals, de ned by the Kyoto Protocol, the issue addressed in this paper concerns the optimal strategy regarding the long-term use of CCS technologies. The aim of this paper is to study the optimal carbon capture and sequestration policy. The CCS technologies has motivated a number of empirical studies, via complex integrated assessment models. This literature always considers that the existing technology allows sequestrating a fraction of the carbon emissions and concludes that the early introduction of sequestration can lead to a substantial decrease in the cost of environmental externality. But, the level of complexity of such operational models, aimed at de ning some speci c climate policies. We develop a very simple growth model so as to obtain analytical and tractable results and therefore exhibit the main driving forces that should determine the optimal CSS policy. We show within this stylized framework that, under some conditions on the cost of extractions, CSS may be a long-term solution for the carbon emissions problem. Besides, it is also shown that the social planner will optimally choose to decrease the rate of capture and sequestration. Besides, we also introduce the decentralization of this simple economy, by considering the individual program of the fossil resource-holder and the one of the representative consumer. This helps us to compute analytically the optimal environmental policy, that is the optimal tax scheme, and also the optimal fossil fuel price pro le.

Alain Ayong; Le Kama; Mouez Fodha; Gilles La Orgue

2009-01-01

348

Damage segregation at fissioning may increase growth rates: A superprocess model  

E-print Network

A fissioning organism may purge unrepairable damage by bequeathing it preferentially to one of its daughters. Using the mathematical formalism of superprocesses, we propose a flexible class of analytically tractable models that allow quite general effects of damage on death rates and splitting rates and similarly general damage segregation mechanisms. We show that, in a suitable regime, the effects of randomness in damage segregation at fissioning are indistinguishable from those of randomness in the mechanism of damage accumulation during the organism's lifetime. Moreover, the optimal population growth is achieved for a particular finite, non-zero level of combined randomness from these two sources. In particular, when damage accumulates deterministically, optimal population growth is achieved by a moderately unequal division of damage between the daughters. Too little or too much division is sub-optimal. Connections are drawn both to recent experimental results on inheritance of damage in protozoans, to the...

Evans, Steven N

2007-01-01

349

Optimally Invariant Variable Combinations for Nonlinear Systems  

E-print Network

Optimally Invariant Variable Combinations for Nonlinear Systems Johannes E. P. J¨aschke Sigurd for achieving optimal operation, by performing all calculations off-line and by determining optimally invariant steps. First, regions of constant active constraints are defined. Second, optimally invariant nonlinear

Skogestad, Sigurd

350

Critical parameters for growth of optimized GaN and InGaN\\/GaN MQW structures on freestanding HVPE GaN substrates by MOCVD  

Microsoft Academic Search

With the continued improvement and availability of freestanding Nitride substrates, such as those grown by HVPE, these substrates are becoming more commonly used for growth and device applications. However, even with a reduced dislocation density as compared to heteroepitaxially grown GaN layers on sapphire or SiC, devices fabricated on these substrates are often less efficient. One reason for this is

James Grandusky; Vibhu Jindal; Neeraj Tripathi; Fatemeh Shahedipour-Sandvik; Alexei Vertiatchikh; Greg Dunne; Hai Lu; Edmund Kaminsky; Rajesh Melkote

2007-01-01

351

Achieving Better Building Performance and Savings Using Optimal Control Strategies  

E-print Network

(DDC). This algorithm is based on mathematical models for the chillers, boilers, chilled and hot water pumps, and air handler fans that relate the power of these components as a function of the chilled water and hot water differential temperature...

Chen, H.; Deng, S.; Bruner, H.

2003-01-01

352

Assisting Pupils in Mathematics Achievement (The Common Core Standards)  

ERIC Educational Resources Information Center

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…

Ediger, Marlow

2011-01-01

353

Entrepreneur achievement. Liaoning province.  

PubMed

This paper reports the successful entrepreneurial endeavors of members of a 20-person women's group in Liaoning Province, China. Jing Yuhong, a member of the Family Planning Association at Shileizi Village, Dalian City, provided the basis for their achievements by first building an entertainment/study room in her home to encourage married women to learn family planning. Once stocked with books, magazines, pamphlets, and other materials on family planning and agricultural technology, dozens of married women in the neighborhood flocked voluntarily to the room. Yuhong also set out to give these women a way to earn their own income as a means of helping then gain greater equality with their husbands and exert greater control over their personal reproductive and social lives. She gave a section of her farming land to the women's group, loaned approximately US$5200 to group members to help them generate income from small business initiatives, built a livestock shed in her garden for the group to raise marmots, and erected an awning behind her house under which mushrooms could be grown. The investment yielded $12,000 in the first year, allowing each woman to keep more than $520 in dividends. Members then soon began going to fairs in the capital and other places to learn about the outside world, and have successfully ventured out on their own to generate individual incomes. Ten out of twenty women engaged in these income-generating activities asked for and got the one-child certificate. PMID:12287775

Zhao, R

1994-03-01

354

Academy of Achievement  

NSDL National Science Digital Library

LetâÂÂs 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 âÂÂmuseum of living historyâÂÂ, 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 âÂÂAchiever GalleryâÂÂ, 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 âÂÂFor Teachersâ section, which offers a number of pedagogical tools specifically aimed towards those in the teaching profession.

355

An integrated microalgal growth model and its application to optimize the biomass production of Scenedesmus sp. LX1 in open pond under the nutrient level of domestic secondary effluent.  

PubMed

Microalgal growth is the key to the coupled system of wastewater treatment and microalgal biomass production. In this study, Monod model, Droop model and Steele model were incorporated to obtain an integrated growth model describing the combined effects of nitrogen, phosphorus and light intensity on the growth rate of Scenedesmus sp. LX1. The model parameters were obtained via fitting experimental data to these classical models. Furthermore, the biomass production of Scenedesmus sp. LX1 in open pond under nutrient level of secondary effluent was analyzed based on the integrated model, predicting a maximal microalgal biomass production rate about 20 g m(-2) d(-1). In order to optimize the biomass production of open pond the microalgal biomass concentration, light intensity on the surface of open pond, total depth of culture medium and hydraulic retention time should be 500 g m(-3), 16,000 lx, 0.2 m and 5.2 d in the conditions of this study, respectively. PMID:23891148

Wu, Yin-Hu; Li, Xin; Yu, Yin; Hu, Hong-Ying; Zhang, Tian-Yuan; Li, Feng-Min

2013-09-01

356

Risk assessment of the use of sub-optimal levels of weak-acid preservatives in the control of mould growth on bakery products  

Microsoft Academic Search

The hurdle technology approach was used to prevent fungal growth of common contaminants of bakery products including isolates belonging to the genera Eurotium, Aspergillus and Penicillium. Several levels (0.003%, 0.03% and 0.3%) of calcium propionate, potassium sorbate and sodium benzoate were assayed on a model agar system in a full-factorial experimental design in which the other factors assayed were pH

S Mar??n; M. E Guynot; P Neira; M Bernadó; V Sanchis; A. J Ramos

2002-01-01

357

Optimization of growth inducing factors for colony forming and attachment of bone marrow-derived mesenchymal stem cells regarding bioengineering application  

PubMed Central

PURPOSE These days, mesenchymal stem cells (MSCs) have received worldwide attention because of their potentiality in tissue engineering for implant dentistry. The purpose of this study was to evaluate various growth inducing factors in media for improvement of acquisition of bone marrow mesenchymal stem cells (BMMSCs) and colony forming unit-fibroblast (CFU-F). MATERIALS AND METHODS The mouse BMMSCs were freshly obtained from female C3H mouse femur and tibia. The cells seeded at the density of 106/dish in media supplemented with different density of fetal bovine serum (FBS), 1?, 25-dihydroxyvitamin (VD3) and recombinant human epidermal growth factor (rhEGF). After 14 days, CFU-F assay was conducted to analyze the cell attachment and proliferation, and moreover for VD3, the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was additionally conducted. RESULTS The cell proliferation was increased with the increase of FBS concentration (P<.05). The cell proliferation was highest at the density of 20 ng/mL rhEGF compared with 0 ng/mL and 200 ng/mL rhEGF (P<.05). For VD3, although the colony number was increased with the increase of its concentration, the difference was not statistically significant (P>.05). CONCLUSION FBS played the main role in cell attachment and growth, and the growth factor like rhEGF played the additional effect. However, VD3 did not have much efficacy compare with the other two factors. Improvement of the conditions could be adopted to acquire more functional MSCs to apply into bony defect around implants easily.

Quan, Hongxuan; Kim, Seong-Kyun; Heo, Seong-Joo; Koak, Jai-Young

2014-01-01

358

Longitudinal Outcomes for Mathematics Achievement for Students with Learning Disabilities  

Microsoft Academic Search

Using longitudinal data from the first 6 waves of the Early Childhood Longitudinal Study–Kindergarten Cohort (ECLS-K), the authors examined mathematics achievement and growth trajectories by learning disability (LD) subgroups. The 2-level (time–student) growth curve model showed that lower levels of mathematics achievement were already evident at kindergarten entry for all subgroups of students identified as LD during the elementary school

Sharon Judge; Silvana M. R. Watson

2011-01-01

359

Does achievement motivation mediate the semantic achievement priming effect?  

PubMed

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. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24820250

Engeser, Stefan; Baumann, Nicola

2014-10-01

360

Optimization Algorithms  

Microsoft Academic Search

\\u000a The right choice of an optimization algorithm can be crucially important in finding the right solutions for a given optimization\\u000a problem. There exist a diverse range of algorithms for optimization, including gradient-based algorithms, derivative-free\\u000a algorithms and metaheuristics. Modern metaheuristic algorithms are often nature-inspired, and they are suitable for global\\u000a optimization. In this chapter, we will briefly introduce optimization algorithms such

Xin-She Yang

361

Taurine supplementation of plant derived protein and n-3 fatty acids are critical for optimal growth and development of cobia, Rachycentron canadum.  

PubMed

We examined growth performance and the 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 canola oil supplemented with the essential fatty acids (EFA) docosahexaenoic acid (DHA) and arachidonic acid (ARA) (~8 % CL). The diet using the thraustochytrid meal plus soybean oil performed equivalently to the fish oil diet; both resulting in significantly higher growth rates, lower feed conversion ratios, and higher survival than the supplemented canola oil diet, even though all three diets were similar in overall energy and met known protein and lipid requirements for cobia. The poor performance of the canola oil diet was attributed to insufficient addition of EFA in the supplemented canola oil source. Increasing levels of EFA in the supplemented canola oil above 0.5 g EFA kg(-1) would likely improve results with cobia. When fish fed either of the fish oil replacement diets were switched to the fish oil control diet, fatty acid profiles of the fillets were observed to transition toward that of the fish oil diet and could be predicted based on a standard dilution model. Based on these findings, a formulated diet for cobia can be produced without fish products providing 100 % survivorship, specific growth rates greater than 2.45 and feed conversion ratios less than 1.5, as long as taurine is added and EFA levels are above 0.5 g EFA kg(-1). PMID:23884630

Watson, Aaron M; Barrows, Frederic T; Place, Allen R

2013-09-01

362

Achievement Motivation: An Investigation of Adolescents' Achievement Patterns.  

ERIC Educational Resources Information Center

Levels of general and area-specific achievement motivation for adolescents of varying backgrounds were assessed. General measures of achievement motivation revealed significant differences by race, sex, and social class. These factors exercised great influence on specific types of achievement behavior. (Author/DWH)

Castenell, Louis A.

1983-01-01

363

Relationships among Projective and Direct Verbal Measures of Achievement Motivation.  

ERIC Educational Resources Information Center

The ways in which projective and nonprojective verbal measures of achievement motivation elicit comparable and dissimilar responses in a "Third World" sample of entrepreneurs and farmers were explored as a test of McClelland's theory of economic growth. Results were generally consistent with the theory of achievement motivation. (Author/JKS)

Singh, Satvir

1979-01-01

364

Autoimmune control of lesion growth in CNS with minimal damage  

NASA Astrophysics Data System (ADS)

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.

Mathankumar, R.; Mohan, T. R. Krishna

2013-07-01

365

OPTIMAL STEEPEST DESCENT ALGORITHMS FOR ...  

E-print Network

for the first time methods for differentiable optimization had their practical efficiency motivated by .... method ensures ?k = O(1/k2), and this means optimal complexity: an error of ? > 0 is achieved in ...... codes are written in Matlab. We solved 60 ...

2008-08-02

366

The Influence of School Policy and Practice on Mathematics Achievement during Transitional Periods  

ERIC Educational Resources Information Center

In this study, the effects of school policies and practices on math achievement growth, as students transitioned from middle to high school, were examined while controlling for school contextual variables. A pattern of accelerated growth in mathematics achievement from grades 8 to 12 occurred, in which higher achieving students in mathematics at…

Holt, Janet K.; Campbell, Cynthia

2004-01-01

367

Cherokee Culture and School Achievement.  

ERIC Educational Resources Information Center

Compares the effect of cooperative and competitive behaviors of Cherokee and Anglo American elementary school students on academic achievement. Suggests changes in teaching techniques and lesson organization that might raise academic achievement while taking into consideration tribal traditions that limit scholastic achievement in an…

Brown, Anthony D.

1980-01-01

368

Contitions for optimal growth of a PSTV-infected potato cell suspension and detection of viroid-complementary longer-than-unit-length RNA in these cells.  

PubMed

A suspension culture from potato spindle tuber viroid (PSTV)-infected cells of the wild type potato (Solanum demissum) has been established, which is a suitable model system for studying PSTV replicationin vivo. The conditions for rapid growth of these cells and for permanent extensive viroid biosynthesis within them are described. Biosynthesis of PSTV in the potato cells was demonstrated by(32)P-incorporation into nucleic acids and their subsequent electrophoretic analysis on polyacrylamide gels. Under optimum culture conditions the amount of(32)P-orthophosphate incorporation into PSTV reached 10% of that incorporated into the 2 M LiCl-soluble cellular RNA. (+)PSTV and its complementary form, i.e. (-)PSTV were identified after their electrophoretic separation on polyacrylamide and agarose gels by molecular hybridization. This analysis revealed the presence of six high molecular weight(-)PSTV species, which are possibly multimers of the unit length(+)PSTV molecule consisting of 359 nucleotides. PMID:24318372

Mühlbach, H P; Faustmann, O; Sänger, H L

1983-09-01

369

Achieving Developmental Synchrony in Young Children With Hearing Loss  

PubMed Central

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

Mellon, Nancy K.; Ouellette, Meredith; Greer, Tracy; Gates-Ulanet, Patricia

2009-01-01

370

RF Gun Optimization Study  

SciTech Connect

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.

Alicia Hofler; Pavel Evtushenko

2007-07-03

371

Parametric Design Optimization By Integrating CAD Systems And Optimization Tools  

NASA Astrophysics Data System (ADS)

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.

Rehan, M.; Olabi, A. G.

2009-11-01

372

Utility Theory for Evaluation of Optimal Process Condition of SAW: A Multi-Response Optimization Approach  

SciTech Connect

Multi-objective optimization problem has been solved in order to estimate an optimal process environment consisting of optimal parametric combination to achieve desired quality indicators (related to bead geometry) of submerged arc weld of mild steel. The quality indicators selected in the study were bead height, penetration depth, bead width and percentage dilution. Taguchi method followed by utility concept has been adopted to evaluate the optimal process condition achieving multiple objective requirements of the desired quality weld.

Datta, Saurav [Department of Mechanical Engineering, National Institute of Technology, Rourkela, Orissa-769008 (India); Biswas, Ajay; Bhaumik, Swapan [Department of Mechanical Engineering, National Institute of Technology, Agartala, Barjala, Tripura (W), Pin-799055 (India); Majumdar, Gautam [Department of Mechanical Engineering, Jadavpur University, Raja S. C. Mallik Road, Kolkata-700032 (India)

2011-01-17

373

Dynamic Optimization  

NASA Technical Reports Server (NTRS)

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.

Laird, Philip

1992-01-01

374

Histone acetyltransferase-deficient p300 mutants in diffuse large B cell lymphoma have altered transcriptional regulatory activities and are required for optimal cell growth  

PubMed Central

Background Recent genome-wide studies have shown that approximately 30% of diffuse large B-cell lymphoma (DLBCL) cases harbor mutations in the histone acetyltransferase (HAT) coactivators p300 or CBP. The majority of these mutations reduce or eliminate the catalytic HAT activity. We previously demonstrated that the human DLBCL cell line RC-K8 expresses a C-terminally truncated, HAT-defective p300 protein (p300?C-1087), whose expression is essential for cell proliferation. Methods Using results from large-scale DLBCL studies, we have identified and characterized a second C-terminally truncated, HAT-defective p300 mutant, p300?C-820, expressed in the SUDHL2 DLBCL cell line. Properties of p300?C-820 were characterized in the SUDHL2 DLBCL cell line by Western blotting, co-immunoprecipitation, and shRNA gene knockdown, as well by using cDNA expression vectors for p300?C-820 in pull-down assays, transcriptional reporter assays, and immunofluorescence experiments. A mass spectrometry-based method was used to compare the histone acetylation profile of DLBCL cell lines expressing various levels of wild-type p300. Results We show that the SUDHL2 cell line expresses a C-terminally truncated, HAT-defective form of p300 (p300?C-820), but no wild-type p300. The p300?C-820 protein has a wild-type ability to localize to subnuclear “speckles,” but has a reduced ability to enhance transactivation by transcription factor REL. Knockdown of p300?C-820 in SUDHL2 cells reduced their proliferation and soft agar colony-forming ability. In RC-K8 cells, knockdown of p300?C-1087 resulted in increased expression of mRNA and protein for REL target genes A20 and I?B?, two genes that have been shown to limit the growth of RC-K8 cells when overexpressed. Among a panel of B-lymphoma cell lines, low-level expression of full-length p300 protein, which is characteristic of the SUDHL2 and RC-K8 cells, was associated with decreased acetylation of histone H3 at lysines 14 and 18. Conclusions The high prevalence of p300 mutations in DLBCL suggests that HAT-deficient p300 activity defines a subtype of DLBCL, which we have investigated using human DLBCL cell lines RC-K8 and SUDHL2. Our results suggest that truncated p300 proteins contribute to DLBCL cell growth by affecting the expression of specific genes, perhaps through a mechanism that involves alterations in global histone acetylation. PMID:24529102

2014-01-01

375

Combined optimization model for sustainable energization strategy  

NASA Astrophysics Data System (ADS)

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.

Abtew, Mohammed Seid

376

Relationship of experimentally aroused achievement motivation to academic achievement anxiety  

Microsoft Academic Search

180 Ss, balanced for sex, were administered the Achievement Anxiety Test (AAT) under experimental conditions producing either minimal or high arousal of achievement motivation. Regression of scholastic aptitude and AAT scores on grade-point average (GPA) showed both AAT scales accounting for the same variance in GPA. Analyses of variance of AAT scores showed no sex differences, but highly significant main

E. Wayne Herron

1964-01-01

377

Model based optimization of some growth process parameters of a Nd:YVO 4 cylindrical bar grown by edge-defined film-fed growth (EFG) method in the presence of the pressure  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to find those values of the radius r0e of the outer edge of the die, pulling rate v, melt temperature T0 at the meniscus basis and pressure p in the furnace, which assure the growth of a Nd:YVO 4 monocrystal cylindrical bar with prescribed radius rf and for which the surface non-uniformity of the bar, due to small uncontrollable oscillations of v and T0, is minimum. Numerical results are given for a Nd:YVO 4 cylindrical bar of 2.5 (mm) radius, grown in a furnace in which the vertical temperature gradient is k = 33 (K/mm) for four type of uncontrollable oscillations: O1 = (? v = ±0.001 (mm/s) and ? T = ±1 (K)), O2 = (? v = ±0.01 (mm/s) and ? T = ±10 (K)), O3 = (? v = ±0.02 (mm/s) and ? T = ±20 (K)), O4 = (? v = ±0.001 (mm/s) and ? T = ±30 (K)), respectively. For a smooth surface, the parameters r0e, v and T0 has to be chosen as follows: r0e = 2.6 (mm), p = 0.002 (atm), v = 0.0011 (mm/s), T0 = 2102 (K) in the case O1; r0e = 2.6 (mm), p = 0.002 (atm), v = 0.0101 (mm/s), T0 = 2100 (K) in the case O2; r0e = 2.7 (mm), p = 0.002 (atm), v = 0.0201 (mm/s), T0 = 2111 (K) in the case O3; r0e = 2.7 (mm), p = 0.002 (atm), v = 0.0011 (mm/s), T0 = 2118 (K) in the case O4.

Braescu, L.; Balint, A. M.; Szabo, R.; Balint, St.

2006-05-01

378

Efficient optimal controller for nuclear power plants  

Microsoft Academic Search

A new scheme for the optimal control of nuclear power plants is proposed. It differs from previous applications of optimal control theory to nuclear reactors in that here it is possible to select the weighting matrices in the quadratic cost functional so that desired pole placement, and subsequent transient response, is achieved. The desired weighting matrix and corresponding optimal control

MEHRDAD SAIF

1989-01-01

379

Optimal quantum cloning via spin networks  

E-print Network

In this paper we present an approach to quantum cloning via free dynamical evolution of spin networks. By properly designing the network and the couplings between spins, we show that optimal 1->M phase covariant cloning can be achieved without any external control. Especially, when M is an odd number, the optimal phase-covariant cloning can be achieved without ancillas. Moreover, we demonstrate that the same framework is capable for optimal 1->2 universal cloning.

Qing Chen; Jianhua Cheng; Ke-Lin Wang; Jiangfeng Du

2005-10-19

380

Time use and change in academic achievement: A longitudinal follow-up  

Microsoft Academic Search

As a follow-up of the research of Smith in 1990, academic achievement results from two years later are added to the data for 1208 of the 1584 seventh and ninth graders for whom Smith studied relationships between achievement and time use. Growth in academic achievement over two years, like contemporaneous achievement, is not positively related to time spent on homework

Thomas Ewin Smith

1992-01-01

381

Stripping accumulation and optimization of HIMM synchrotron  

NASA Astrophysics Data System (ADS)

The design of an injection system for a dedicated carbon-ion therapy synchrotron is presented. Improvements to the particle tracking code ACCSIM are developed to support interactions between heavy ions and stripping foil. The three main improvements are concerned with (a) charge exchange between carbon ions and stripping foil; (b) multiple Coulomb scattering of incident heavy ions on stripping foil; and (c) energy loss in particles passing through the foil, and energy-loss straggling. The accumulation process is then simulated, and the parameters related to the injection system are optimized. A gain of about 140 in the number of particles is achieved, and the emittance and momentum spread growth is obtained, together with a central momentum shift. Finally, the superacceptance of the synchrotron, ?-?p/p, is tracked. According to the simulation, 1.35×109 actual particles are stored successfully in the synchrotron.

Chai, Weiping; Yang, Jiancheng; Xia, Jiawen; Yuan, Youjin; Shi, Jian; Yin, Dayu; Li, Peng; Shen, Guodong; Qu, Guofeng; Gao, Xiang

2014-11-01

382

General Achievement Trends: North Carolina  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

383

General Achievement Trends: Rhode Island  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

384

General Achievement Trends: New Hampshire  

ERIC Educational Resources Information Center

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…

Center on Education Policy, 2009

2009-01-01

385

Five Standards and Student Achievement  

Microsoft Academic Search

Two studies examine the influence of the Standards for Effective Pedagogy on student achievement gains. Participants were 15 teachers and 266 students (grades 3 to 5) in a public elementary school serving predominantly low-income Latino English Language Learners (ELLs). Study 1 found that higher use of the standards by teachers reliably predicted student achievement gains on SAT-9 tests of comprehension,

R. William Doherty; R. Soleste Hilberg; America Pinal; Roland G. Tharp

2003-01-01

386

Teaching the Low Level Achiever.  

ERIC Educational Resources Information Center

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);…

Salomone, Ronald E., Ed.

1986-01-01

387

Teacher Morale and Student Achievement.  

ERIC Educational Resources Information Center

Identifies statistical relationships between teacher morale and student achievement test scores in reading. Suggests teachers' attitudes toward classroom evaluation systems, as well as their perceptions of the functional behaviors of the principal, were the strongest predictors of students' achievements in reading. (RAE)

White, William F.; Stevens, Rita

1988-01-01

388

Poor Results for High Achievers  

ERIC Educational Resources Information Center

Three million students in the United States are classified as gifted, yet little is known about the effectiveness of traditional gifted and talented (G&T) programs. In theory, G&T programs might help high-achieving students because they group them with other high achievers and typically offer specially trained teachers and a more advanced…

Bui, Sa; Imberman, Scott; Craig, Steven

2012-01-01

389

VEHICLE NETWORKS: ACHIEVING REGULAR FORMATION  

Microsoft Academic Search

In this paper we will consider a network of vehicles exchanging information among themselves with the intention of achieving a specied polygonal formation. The network achieves the formation through decentralized feedback control, which is con- structed from the available information. Several information o w laws are considered in order to improve the performance of the vehicle network. A stochastic model

MADALENA CHAVES; ROBERT DAY; LUCIA GOMEZ-RAMOS; PARTHASARATHI NAG; ANCA WILLIAMS; WEI ZHANG

2002-01-01

390

Anxiety in academic achievement situations  

Microsoft Academic Search

Scales of general anxiety (Taylor, Welsh, and Freeman) and of anxiety specific to academic situations (Mandler-Sarason, Achievement Anxiety Test) were administered to college freshmen. Academic achievement included verbal aptitude, the Scholastic Aptitude Test, overall grade-point average, and performance in psychology courses. The 2 tests of specific anxiety were seen to be measuring something different than the more general tests and

R. Alpert; R. N. Haber

1960-01-01

391

Understanding and Fostering Achievement Motivation  

ERIC Educational Resources Information Center

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…

Klose, Laurie McGarry

2008-01-01

392

Porous plant growth media design considerations for Lunar and Martian habitats  

Microsoft Academic Search

Lunarand Martian-based plant growth facilities pose novel challenges to the design and management of porous medium-based root-zone environments. An optimized 10 cm tall root zone on earth would require 60 cm to achieve the same relative water content distribution in a lunar greenhouse. For adapting lunar gravity to the desired size (e.g., 10 cm), one could theoretically scale the water

Scott Jones; Robert Heinse; Bruce Bugbee; Dani; Gail Bingham

2008-01-01

393

Optimal Centroid Position Estimation  

SciTech Connect

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.

Candy, J V; McClay, W A; Awwal, A S; Ferguson, S W

2004-07-23

394

Realizable protocols for optimal administration of drugs in mathematical models for anti-angiogenic treatment.  

PubMed

Two mathematical models for tumour anti-angiogenesis, one originally formulated by Hahnfeldt et al. (1999, Tumor development under angiogenic signaling: a dynamical theory of tumor growth, treatment response, and postvascular dormancy. Cancer Res., 59, 4770-4775) and a modification of this model by Ergun et al. (2003, Optimal scheduling of radiotherapy and angiogenic inhibitors. Bull. Math. Biol., 65, 407-424) are considered as optimal control problem with the aim of maximizing the tumour reduction achievable with an a priori given amount of angiogenic agents. For both models, depending on the initial conditions, optimal controls may contain a segment along which the dosage follows a so-called singular control, a time-varying feedback control. In this paper, for these cases, the efficiency of piecewise constant protocols with a small number of switchings is investigated. Through comparison with the theoretically optimal solutions, it will be shown that these protocols provide generally excellent suboptimal strategies that for many initial conditions come within a fraction of 1% of the theoretically optimal values. When the duration of the dosages are a priori restricted to a daily or semi-daily regimen, still very good approximations of the theoretically optimal solution can be achieved. PMID:20513667

Ledzewicz, Urszula; Marriott, John; Maurer, Helmut; Schättler, Heinz

2010-06-01

395

Deploying wireless sensors to achieve both coverage and connectivity  

Microsoft Academic Search

It is well-known that placing disks in the triangular lattice pat- tern is optimal for achieving full coverage on a plane. With the emergence of wireless sensor networks, however, it is now no longer enough to consider coverage alone when deploy- ing a wireless sensor network; connectivity must also be con- sidered. While moderate loss in coverage can be tolerated

Xiaole Bai; Santosh Kumar; Dong Xuan; Ziqiu Yun; Ten-hwang Lai

2006-01-01

396

Achieving Tobacco Cessation: Current Status, Current Problems, Future Possibilities  

Microsoft Academic Search

Assisting smokers to achieve tobacco cessation has always been difficult. The development of pharmacological approaches to the attainment of abstinence from tobacco usage has been very helpful, although our understanding of optimal clinical use is still incomplete and imperfect. Bupropion and nicotine therapy (NT) will help reduce the severity of nicotine withdrawal symptoms, whether used separately or in combination. Effectiveness

Laszlo T. Vaszar; Priscilla S. A. Sarinas; Glen A. Lillington

2002-01-01

397

Small business growth through geographic expansion  

Microsoft Academic Search

Although the small business sector as a whole is achieving phenomenal growth, an important concern in the field has been identifying the problems, challenges, and success characteristics associated with the prudent growth of individual firms. A strategy utilized by many small firms to achieve their growth objectives is one of geographic expansion. This approach involves expanding a firm’s business from

Bruce R. Barringer; Daniel W. Greening

1998-01-01

398

Class, Race, and Educational Achievement  

Microsoft Academic Search

\\u000a The relationship between class, race, and educational achievement has been a focus of considerable research attention and\\u000a debate concerning educational policy and practice for most of the past century. The literature, however, has generally neglected\\u000a to discuss how race, class, and educational achievement are intertwined. The related issues have been difficult to untwine\\u000a and understand because of their embeddedness in

Brenda X. Mejia-Smith; Edmund W. Gordon

399

Damage segregation at fissioning may increase growth rates  

PubMed Central

A fissioning organism may purge unrepairable damage by bequeathing it preferentially to one of its daughters. Using the mathematical formalism of superprocesses, we propose a flexible class of analytically tractable models that allow quite general effects of damage on death rates and splitting rates and similarly general damage segregation mechanisms. We show that, in a suitable regime, the effects of randomness in damage segregation at fissioning are indistinguishable from those of randomness in the mechanism of damage accumulation during the organism’s lifetime. Moreover, the optimal population growth is achieved for a particular finite, non-zero level of combined randomness from these two sources. In particular, when damage accumulates deterministically, optimal population growth is achieved by a moderately unequal division of damage between the daughters, while too little or too much division is sub-optimal. Connections are drawn both to recent experimental results on inheritance of damage in protozoans, and to theories of aging and resource division between siblings. PMID:17442356

Evans, Steven N.; Steinsaltz, David

2007-01-01

400

Using nonlinear transient growth to construct the minimal seed for shear flow turbulence.  

PubMed

Linear transient growth analysis is commonly used to suggest the structure of disturbances which are particularly efficient in triggering transition to turbulence in shear flows. We demonstrate that the addition of nonlinearity to the analysis can substantially change the prediction made in pipe flow from simple two-dimensional streamwise rolls to a spanwise and cross-stream localized three-dimensional state. This new nonlinear optimal is demonstrably more efficient in triggering turbulence than the linear optimal indicating that there are better ways to design perturbations to achieve transition. PMID:21230910

Pringle, Chris C T; Kerswell, Rich R

2010-10-01

401

Using Nonlinear Transient Growth to Construct the Minimal Seed for Shear Flow Turbulence  

NASA Astrophysics Data System (ADS)

Linear transient growth analysis is commonly used to suggest the structure of disturbances which are particularly efficient in triggering transition to turbulence in shear flows. We demonstrate that the addition of nonlinearity to the analysis can substantially change the prediction made in pipe flow from simple two-dimensional streamwise rolls to a spanwise and cross-stream localized three-dimensional state. This new nonlinear optimal is demonstrably more efficient in triggering turbulence than the linear optimal indicating that there are better ways to design perturbations to achieve transition.

Pringle, Chris C. T.; Kerswell, Rich R.

2010-10-01

402

Modeling of transport processes and kinetics of silicon carbide bulk growth  

NASA Astrophysics Data System (ADS)

The diameter of silicon carbide (SiC) single crystal grown by the physical vapor transport method has increased significantly in recent years. Process modeling has played an important role in designing and developing the large diameter SiC growth systems. The numerical algorithm incorporates the calculations of radio-frequency, time-harmonic magnetic field by induction heating, radiation and conduction heat transfer in the system, as well as the growth kinetics. The generated power density in the graphite susceptor is obtained by solving the magnetic vector potential equations, and radiative heat transfer is calculated from the integrated equations for radiation. Chemical reactions and transport of gaseous species, Si2C, SiC2, SiC and Si, are also considered. A growth kinetics model is proposed for the first time, which uses the Hertz-Knudsen equation to relate the growth rate to the supersaturation of a rate-determining vapor species, the driving force for the deposition. The theoretical predictions compare reasonably with the published experimental data. The growth rate curves are obtained as a function of growth temperature and system pressure. The growth kinetics is greatly influenced by the inert gas pressure, temperature and temperature gradient. Since the vapor pressure is an ascending function of the temperature, for low temperature growth, a larger temperature gradient is needed in order to achieve the desired level of supersaturation (or growth rate). A low temperature growth is usually associated with small diameter systems, which maintain larger temperature differences. At a high growth temperature, since the vapor pressure is high, only a small temperature difference is required to achieve the same level of supersaturation. Desirable growth temperature and growth rate profiles can be obtained across the seed surface by optimizing the furnace components, such as the graphite susceptor, induction coil, and insulation materials.

Chen, Q.-S.; Zhang, H.; Ma, R.-H.; Prasad, V.; Balkas, C. M.; Yushin, N. K.

2001-05-01

403

Electrodialysis simulation to achieve optimum current density  

NASA Technical Reports Server (NTRS)

Electrodialysis is used to remove salts from waste or other water streams, to yield a concentrated brine and a substatially deionized product water. During the electrodialysis process, the boundary layer adjacent to the ion selective membrane can become depleted of ions, resulting in severe pH changes sometimes accompanied by precipitation, and power losses, by a process known as water splitting. In order to optimize the applied electric current density, to achieve maximum deionization without exceeding the limiting current at any point along the path, a simulation program has been created to plot ion concentrations and fluxes, and cell current densities and voltages along the electrodialysis path. A means for tapering the current density along the path is recommended.

Herrmann, Cal C.

1993-01-01

404

Achieving Micelle Control through Core Crystallinity  

PubMed Central

We have designed a pathway for controlling the critical micelle concentration and micelle size of polyester-based systems. This was achieved by creating an array of different copolymers with semicrystalline or amorphous hydrophobic blocks. The hydrophobic block was constructed through ring-opening polymerization of ?-caprolactone, l-lactide, and ?-decalactone, either as homopolymers or random copolymers, using PEG as both the initiator and the hydrophilic block. Micelles formed with amorphous cores exhibited considerably higher critical micelle concentrations than those with semicrystalline cores. Micelles with amorphous cores also became larger in size with an increased molecular weight of the hydrophobic bock, in contrast to micelles with semicrystalline cores, which displayed the opposite behavior. Hence, core crystallinity was found to be a potent tool for tailoring micelle properties and thereby facilitating the optimization of drug delivery systems. The introduction of PEG-P?DL also proved to be a valuable asset in the tuning of micelle properties. PMID:24066701

2013-01-01

405

Optimization approach to entanglement distillation  

E-print Network

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.

T. Opatrny; G. Kurizki

1998-11-30

406

Behavioral Engagement in Learning and Math Achievement over Kindergarten: A Contextual Analysis  

ERIC Educational Resources Information Center

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…

Robinson, Keith; Mueller, Anna S.

2014-01-01

407

Type A achievement striving and failure to achieve personal goals  

Microsoft Academic Search

The purpose of the present study was to examine relations involving the Type A behavior pattern, goal-setting behavior, and goal achievement. Type A and B subjects completed two sequential general information tests. On each test, subjects were required to establish a performance goal prior to the test, and after completing the test, subjects were given feedback on their actual performance.

Clay H. Ward; Richard M. Eisler

1987-01-01

408

Localization performance comparison using optimal and sub-optimal lateration in WSNs  

Microsoft Academic Search

This paper compares methods of localization in order to try and reduce the processing overhead of optimal multi-lateration whilst still achieving close to its accuracy. Three methods of localization are examined, firstly optimal multi-lateration (OML), which provides the benchmark in terms of accuracy achievable. Secondly sub-optimal blind trilateration (SBT) which randomly selects the minimum feasible number of anchors. This defines

H. K. Maheshwari; A. H. Kemp; B. Peng

2009-01-01

409

Temperature effect on growth, and selected parameters of Phaeodactylum tricornutum in batch cultures.  

PubMed

The effect of optimal and stress temperatures on the growth kinetics of the Phaeodactylum tricornutum CCAP/1055/1 strain (a model diatom with a known genome sequence) in batch cultures was examined. The analysis of the obtained results showed two phases of culture growth. There were significant positive correlations between OD increase of chlorophyll a chlorophyll c and protein concentration at different temperatures. The Fv/Fm parameter achieved a maximum level on the 6(th) or 7(th) day and then decreased to the values registered on the first day of observation. Genetic material undergoes gradual degradation 10 days after inoculation. The size of the cells was invariable. PMID:24432347

Bojko, Monika; Brzostowska, Klaudia; Kuczy?ska, Paulina; Latowski, Dariusz; Olchawa-Pajor, Monika; Krzeszowiec, Weronika; Waloszek, Andrzej; Strza?ka, Kazimierz

2013-01-01

410

Akamai technologies : an analysis of product and platform growth strategies  

E-print Network

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 ...

Piper, Victor L. (Victor Lawrence)

2013-01-01

411

Mathematical Optimization  

NSDL National Science Digital Library

Some of the most fundamental problems in engineering, science, and mathematics would take the most powerful computer in the world several lifetimes to find an optimal solution. However, near-optimal solutions to many of these problems have been discovered thanks to various methods of mathematical optimization. This Topic in Depth looks at some optimization techniques and the areas to which they have been applied.Argonne National Laboratory hosts an online guide (1) to some of the most well known optimization problems and algorithms. People who are new to the subject can find a wealth of introductory material in the Optimization Tree section, and several applications are illustrated with interactive demonstrations in the Case Studies section. Optimization has roots in operations research, and this tutorial (2) covers many topics within OR. A fun applet requires the user to place as many queens on a chess board as possible without any two being in direct line-of-sight, and an accompanying discussion shows how linear programming can be used to solve this problem; this is one of many resources contained within the tutorial. Two chemical engineering professors at Carnegie Mellon University are the authors of Retrospective on Optimization (3), a fairly comprehensive paper chronicling the history of optimization problems and the development of solution methods. The 51-page document is divided into two main parts; the first outlines some of the most significant advances in the field, and the second looks ahead toward key areas of research needed to evolve optimization further. Highway planning and development is the focus of this paper (4), which proposes using, among other things, genetic algorithms to optimize highway alignment. The authors state that this technique could be used to avoid delays and added costs due to changing plans later in the construction process. Another use of genetic algorithms in optimization is highlighted in this document from the German Aerospace Center (5). The document describes how a novel method for robot design, which involves formulating mathematical representations of robotic constraints and kinematics. These figures can then be used as parameters in a genetic algorithm that would optimize component placement while maintaining the desired functionality. A joint effort between architecture and mechanical engineering researchers at the University of Michigan (6) applied geometrical and topological optimization techniques to building floorplan layout. In the course of their research, they developed an optimization tool that is briefly described and can be downloaded from a Web site given in the paper. The Mathematical Programming Glossary (7) contains short discussions of hundreds of terms related to optimization theory. Each entry includes a clear definition and hyperlinks to other terms, and some of the entries are accompanied by a more in-depth supplement. One of the best sources for current research papers and reports is Optimization Online (8). This repository receives numerous submissions each month, and papers can be browsed by data added or category.

Leske, Cavin.

412

Designing Sensor Networks by a Generalized Highly Optimized Tolerance Model  

NASA Astrophysics Data System (ADS)

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.

Miyano, Takaya; Yamakoshi, Miyuki; Higashino, Sadanori; Tsutsui, Takako

413

Distributed Optimization  

NASA Technical Reports Server (NTRS)

We demonstrate a new framework for analyzing and controlling distributed systems, by solving constrained optimization problems with an algorithm based on that framework. The framework is ar. information-theoretic extension of conventional full-rationality game theory to allow bounded rational agents. The associated optimization algorithm is a game in which agents control the variables of the optimization problem. They do this by jointly minimizing a Lagrangian of (the probability distribution of) their joint state. The updating of the Lagrange parameters in that Lagrangian is a form of automated annealing, one that focuses the multi-agent system on the optimal pure strategy. We present computer experiments for the k-sat constraint satisfaction problem and for unconstrained minimization of NK functions.

Macready, William; Wolpert, David

2005-01-01

414

Scheduling and Achievement. Research Brief  

ERIC Educational Resources Information Center

To use a block schedule or a traditional schedule? Which structure will produce the best and highest achievement rates for students? The research is mixed on this due to numerous variables such as: (1) socioeconomic levels; (2) academic levels; (3) length of time a given schedule has been in operation; (4) strategies being used in the classrooms;…

Walker, Karen

2006-01-01

415

Graders' Mathematics Achievement  

ERIC Educational Resources Information Center

The purpose of this experimental study was to investigate the effects of metacognitive reflective assessment instruction on student achievement in mathematics. The study compared the performance of 141 students who practiced reflective assessment strategies with students who did not. A posttest-only control group design was employed, and results…

Bond, John B.; Ellis, Arthur K.

2013-01-01

416

Sociocultural Variation in Literacy Achievement  

ERIC Educational Resources Information Center

The purpose of this study was to describe the variations in literacy achievement among native and non-native upper primary school children (grades three to six) in the Netherlands. Various measures of word decoding, reading literacy and writing skill were collected from 1091 native Dutch children, 753 children with a former Dutch colonial…

Verhoeven, Ludo

2006-01-01

417

Gender Differences in Spelling Achievement.  

ERIC Educational Resources Information Center

In this study, gender differences in spelling achievement were investigated for young adults (ages 17 to 21). Performances of males and females on standardized and written spelling tests were compared. All of the 40 students (20 males and 20 females) are from a low-economic, inner city, vocational program. The students were also given a…

Rios, Daisy M.

418

Florida's Fit to Achieve Program.  

ERIC Educational Resources Information Center

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…

Sander, Allan N.; And Others

1993-01-01

419

Gender Differences in Gifted Achievement  

Microsoft Academic Search

In Britain, the academic achievements of gifted girls in grade school are surpassing those of gifted boys in almost all areas of study and at all ages, whereas this does not appear to be the case in the USA. The evidence suggests two major reasons for this difference. Emotionally, British girls are now showing greater confidence in their abilities. Educationally,

Joan Freeman

420

Socioeconomic Determinants of Academic Achievement  

ERIC Educational Resources Information Center

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…

Tomul, Ekber; Savasci, Havva Sebile

2012-01-01

421

The Racial Academic Achievement Gap  

ERIC Educational Resources Information Center

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…

Green, Toneka M.

2008-01-01

422

School Desegregation and Black Achievement.  

ERIC Educational Resources Information Center

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…

Cook, Thomas; And Others

423

Teacher Influences on Student Achievement  

Microsoft Academic Search

Research spanning two decades indicates that effective teaching demands the orchestration of a wide array of skills that must be adapted to specific contexts. Brophy reviews research that indicates that students achieve more when their teachers emphasize academic objectives in establishing expectations and allocating time, use effective management strategies to ensure that academic learning time is maximized, pace students through

Jere Brophy

1986-01-01

424

Meeting a Math Achievement Crisis  

ERIC Educational Resources Information Center

An urban community spotlighted declining mathematics achievement and took some measures, in which the students' performance increased substantially. The Benjamin Banneker Charter Public School in Cambridge, Massachusetts, engaged the entire community and launched the campaign called "Math Everywhere", which changed Benjamin Banneker's culture as…

Jennings, Lenora; Likis, Lori

2005-01-01

425

Can Judges Improve Academic Achievement?  

ERIC Educational Resources Information Center

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…

Greene, Jay P.; Trivitt, Julie R.

2008-01-01

426

Academic Achievement Programs. Student Handbook.  

ERIC Educational Resources Information Center

This University of Maryland, College Park student handbook is intended as a reference to help academic achievement program (AAP) students successfully navigate the campus and the academic services available. Sections of the handbook cover the history, philosophy, and mission of the AAP; describe a summer transitional program; list the five program…

Maryland Univ., College Park.

427

Creativity and Achievement in Speech.  

ERIC Educational Resources Information Center

The purposes of this study were to determine if there is any relationship between: (1) students' creative thinking ability and their achievement in the basic college course in public speaking, and (2) teachers' estimates of creative thinking ability when compared to students' scores on a standardized creative thinking test. Subjects were 140…

Rossiter, Charles M., Jr.

1970-01-01

428

Explaining Achievement in Higher Education  

ERIC Educational Resources Information Center

This research project investigated the relationship between students' pre-entry characteristics, perceptions of the learning environment, reported work discipline, the use of deep information processing strategies, and academic achievement. Ability measured by grade-point average in pre-university education was the most important predictor of…

Jansen, Ellen P. W. A.; Bruinsma, Marjon

2005-01-01

429

Literacy Achievement in Nongraded Classrooms  

ERIC Educational Resources Information Center

This longitudinal quantitative study compared literacy achievement of students from second through sixth grade based on two organizational systems: graded (traditional) and nongraded (multiage) classrooms. The California Standards Test (CST) scaled and proficiency scores for English-Language Arts (ELA) were used as the study's independent variable…

Kreide, Anita Therese

2011-01-01

430

MPEG21: Goals and Achievements  

Microsoft Academic Search

MPEG-21 is an open standards-based framework for multimedia delivery and consumption. It aims to enable the use of multimedia resources across a wide range of networks and devices. We discuss MPEG-21's parts, achievements, ongoing activities, and opportunities for new technologies.

Ian S. Burnett; Rik Van De Walle; Keith Hill; Jan Bormans; Fernando Pereira

2003-01-01

431

OF ACHIEVEMENT Trends in International  

E-print Network

achievement at the fourth and eighth grades. TIMSS 2015 will be the sixth assessment, resulting in a 20-year.g., fourth grade mathematics, eighth grade science). A major purpose of TIMSS is to provide important for students in their final year of secondary school (twelfth grade in most countries). The assessment provides

Huang, Jianyu

432

Risk modelling in portfolio optimization  

NASA Astrophysics Data System (ADS)

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.

Lam, W. H.; Jaaman, Saiful Hafizah Hj.; Isa, Zaidi

2013-09-01

433

Entropy, environment, and endogenous economic growth  

Microsoft Academic Search

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.

Sjak Smulders

1995-01-01

434

Optimizing Optimism in Systems Engineers  

E-print Network

Biases continue to be an important aspect of human judgment and decision making because they often occur subconsciously and can frequently lead to unfavorable outcomes. Optimism bias is one type of cognitive illusion that ...

Valerdi, Dr. Ricardo

2009-11-18

435

Expert System Control of Plant Growth in an Enclosed Space  

NASA Technical Reports Server (NTRS)

The Expert System is an enclosed, controlled environment for growing plants, which incorporates a computerized, knowledge-based software program that is designed to capture the knowledge, experience, and problem-solving skills of one or more human experts in a particular discipline. The Expert System is trained to analyze crop/plant status, to monitor the condition of the plants and the environment, and to adjust operational parameters to optimize the plant-growth process. This system is intended to provide a way to remotely control plant growth with little or no human intervention. More specifically, the term control implies an autonomous method for detecting plant states such as health (biomass) or stress and then for recommending and implementing cultivation and/or remediation to optimize plant growth and to minimize consumption of energy and nutrients. Because of difficulties associated with delivering energy and nutrients remotely, a key feature of this Expert System is its ability to minimize this effort and to achieve optimum growth while taking into account the diverse range of environmental considerations that exist in an enclosed environment. The plant-growth environment for the Expert System could be made from a variety of structures, including a greenhouse, an underground cavern, or another enclosed chamber. Imaging equipment positioned within or around the chamber provides spatially distributed crop/plant-growth information. Sensors mounted in the chamber provide data and information pertaining to environmental conditions that could affect plant development. Lamps in the growth environment structure supply illumination, and other additional equipment in the chamber supplies essential nutrients and chemicals.

May, George; Lanoue, Mark; Bathel, Matthew; Ryan, Robert E.

2008-01-01

436

Optimal Implementation of Intervention Strategies for Elderly People with Ludomania  

PubMed Central

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

Kim, Byul Nim; Masud, M.A.; Kim, Yongkuk

2014-01-01

437

Entropy production of a steady-growth cell with catalytic reactions  

E-print Network

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.

Yusuke Himeoka; Kunihiko Kaneko

2014-03-15

438

Online and Offline Algorithmic Techniques for Communication Performance Optimization in Distributed Systems  

E-print Network

Online and Offline Algorithmic Techniques for Communication Performance Optimization in Distributed of communication optimization in distributed systems. Communication is a key issue in every distributed system and, since good communication performance is often difficult to achieve, optimization techniques are welcome

Paris-Sud XI, Université de

439

Recombinant collagen production optimization in Escherichia coli  

E-print Network

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 ...

Whittemore, Brett A

2005-01-01

440

Metacognition, Achievement Goals, Study Strategies and Academic Achievement: Pathways to Achievement  

ERIC Educational Resources Information Center

The purpose of this research was to develop and test a model of effective self-regulated learning. Based on effort expenditure we discerned effective self-regulators and less effective self-regulators. The model comprised achievement goals (mastery, performance-approach and -avoidance goals), metacognition (metacognitive knowledge, regulation and…

Vrugt, Anneke; Oort, Frans J.

2008-01-01

441

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

PubMed Central

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 E (embryonic day) 21 to E100] revealed a unique pattern of growth and differentiation for each embryonic organ. Maximal liver growth and function were achieved at the earliest teratoma-free gestational age (E28), whereas the growth and functional potential of the pancreas gradually increased toward E42 and E56 followed by a marked decline in insulin-secreting capacity at E80 and E100. Development of mature lung tissue containing essential respiratory system elements was observed at a relatively late gestational age (E56). These findings, showing distinct, optimal gestational time windows for transplantation of embryonic pig liver, pancreas, and lung, might explain, in part, the disappointing results in previous transplantation trials and could help enhance the chances for successful implementation of embryonic pig tissue in the treatment of a wide spectrum of human diseases. PMID:15710886

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

2005-01-01

442

A Review of Evolutionary Multiobjective Optimization  

E-print Network

directions for future research. I. INTRODUCTION The effectiveness of evolutionary computation methodologies years. A number of evolutionary multiobjective optimization (EMO) methodologies have been developed and are being continuously improved in order to achieve better performance. These techniques have illustrated

Coello, Carlos A. Coello