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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

Achieving Egyptian Export Growth. Final Report.  

National Technical Information Service (NTIS)

This study assesses Egypt's prospects for export growth, sets forth an 'export vision' in which Egypt will double its nontraditional merchandise exports in 4 years and triple them in 6, and proposes a strategy for achieving this vision. Introductory secti...

1995-01-01

3

Student Achievement and National Economic Growth  

ERIC Educational Resources Information Center

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

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

2006-01-01

4

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

5

How do some companies achieve high growth?  

Microsoft Academic Search

Wonders why, in an atmosphere of intense competition, some companies achieve sustained high growth in profits and revenues. Highlights the example of Formule 1, a chain of budget hotels in France, launched in 1985, which beat off the no-star and one-star hotels, costing between 60 and 90 francs, and with 2 stars at double the price. Demonstrates that Formule 1's

T Kippenberger

1997-01-01

6

The Effects of Academic Optimism on Elementary Reading Achievement  

ERIC Educational Resources Information Center

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

Bevel, Raymona K.; Mitchell, Roxanne M.

2012-01-01

7

Academic Optimism of Schools: A Force for Student Achievement  

ERIC Educational Resources Information Center

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…

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

2006-01-01

8

Reading Achievement Growth in Children with Language Impairments  

ERIC Educational Resources Information Center

Purpose: This study examined the reading achievement growth of children with language impairments (LI) across the school grades. The authors sought to determine whether children with LI demonstrate a delayed, deficit, or cumulative pattern of reading achievement growth when compared with children with typical language (TL). Method: A group of 225…

Catts, Hugh W.; Bridges, Mindy Sittner; Little, Todd D.; Tomblin, J. Bruce

2008-01-01

9

Simulated annealing algorithm for optimal capital growth  

NASA Astrophysics Data System (ADS)

We investigate the problem of dynamic optimal capital growth of a portfolio. A general framework that one strives to maximize the expected logarithm utility of long term growth rate was developed. Exact optimization algorithms run into difficulties in this framework and this motivates the investigation of applying simulated annealing optimized algorithm to optimize the capital growth of a given portfolio. Empirical results with real financial data indicate that the approach is inspiring for capital growth portfolio.

Luo, Yong; Zhu, Bo; Tang, Yong

2014-08-01

10

Academic Optimism and Student Achievement in Urban Elementary Schools  

ERIC Educational Resources Information Center

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…

Smith, Page A.; Hoy, Wayne K.

2007-01-01

11

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

12

Optimal consumption models in economic growth  

NASA Astrophysics Data System (ADS)

We study the optimal consumption problem in the one-sector model of economic growth under uncertainty. We show the existence of a classical solution of the Hamilton-Jacobi-Bellman equation associated with the stochastic optimization problem, and then give an optimal consumption policy in terms of its solution.

Morimoto, Hiroaki

2008-01-01

13

Some Environmental Aspects of Optimal Economic Growth.  

National Technical Information Service (NTIS)

A multi-sector model of an economy is formulated, discussed, and analysed. Contrary to most of the literature on optimal economic growth it is assumed that the society is not purely consumption maximizing. Thus, environmental disutilities are integrated i...

H. U. Buhl

1983-01-01

14

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

15

The optimal polarizations for achieving maximum contrast in radar images  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

16

Optimal Growth with Robust Feedback Control.  

National Technical Information Service (NTIS)

Optimal control theory is no less important in economics today than welfare economics was twenty years ago. It is used to evaluate different growth paths; and it forms a crucial part of the long-run theory of the firm. It has been used to derive an aggreg...

E. F. Infante J. L. Stein

1972-01-01

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.

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

2013-01-01

18

Adaptation to optimal cell growth through self-organized criticality.  

PubMed

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. PMID:23003193

Furusawa, Chikara; Kaneko, Kunihiko

2012-05-18

19

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

20

Achieving Optimal Privacy in Trust-Aware Social Recommender Systems  

NASA Astrophysics Data System (ADS)

Collaborative filtering (CF) recommenders are subject to numerous shortcomings such as centralized processing, vulnerability to shilling attacks, and most important of all privacy. To overcome these obstacles, researchers proposed for utilization of interpersonal trust between users, to alleviate many of these crucial shortcomings. Till now, attention has been mainly paid to strong points about trust-aware recommenders such as alleviating profile sparsity or calculation cost efficiency, while least attention has been paid on investigating the notion of privacy surrounding the disclosure of individual ratings and most importantly protection of trust computation across social networks forming the backbone of these systems. To contribute to addressing problem of privacy in trust-aware recommenders, within this paper, first we introduce a framework for enabling privacy-preserving trust-aware recommendation generation. While trust mechanism aims at elevating recommender's accuracy, to preserve privacy, accuracy of the system needs to be decreased. Since within this context, privacy and accuracy are conflicting goals we show that a Pareto set can be found as an optimal setting for both privacy-preserving and trust-enabling mechanisms. We show that this Pareto set, when used as the configuration for measuring the accuracy of base collaborative filtering engine, yields an optimized tradeoff between conflicting goals of privacy and accuracy. We prove this concept along with applicability of our framework by experimenting with accuracy and privacy factors, and we show through experiment how such optimal set can be inferred.

Dokoohaki, Nima; Kaleli, Cihan; Polat, Huseyin; Matskin, Mihhail

21

Science Achievement Growth Trajectories: Understanding Factors Related to Gender and Racial-Ethnic Differences in Precollege Science Achievement.  

ERIC Educational Resources Information Center

Used hierarchical linear modeling and longitudinal data from the first three waves of the National Education Longitudinal Study to examine achievement and growth rates in precollege science by racial, ethnic, and gender subgroups. Findings show socioeconomic status and previous grades to be strongly related to eighth-grade achievement across all…

Muller, Patricia A.; Stage, Frances K.; Kinzie, Jillian

2001-01-01

22

Achieving Hazard-Resilient Coastal & Waterfront Smart Growth.  

National Technical Information Service (NTIS)

Smart growth strategies and hazard mitigation measures have similar goals. Both aim to make communities safer, healthier, and fiscally responsible. Communities across the nation use smart growth strategies to ensure that new development or redevelopment b...

2012-01-01

23

The influence of optimism and pessimism on student achievement in mathematics  

NASA Astrophysics Data System (ADS)

Students' causal attributions are not only fundamental motivational variables but are also critical motivators of their persistence in learning. Optimism, pessimism, and achievement in mathematics were measured in a sample of primary and lower secondary students on two occasions. Although achievement in mathematics was most strongly related to prior achievement and grade level, optimism and pessimism were significant factors. In particular, students with a more generally pessimistic outlook on life had a lower level of achievement in mathematics over time. Gender was not a significant factor in achievement. The implications of these findings are discussed.

Yates, Shirley M.

2002-11-01

24

The optimal achievement model and underachievement in Hong Kong: an application of the Rasch model  

Microsoft Academic Search

Termed the optimal achievement model, a new method for the estimation of underachievement re- lies on measuring student potential (P) and achievement (A) using Rasch models and calculating an achievement index, IA, for each individual. This study extends a previous report (Phillipson & Tse, 2007) that estimated the proportion of Hong Kong students in Primary 5 to now include a

SHANE N. PHILLIPSON

2008-01-01

25

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

26

Singapore Economic Achievement: A Model for Rapid Growth.  

National Technical Information Service (NTIS)

Since 1959 when Singapore achieved self-government and particularly 1965 when Singapore became an independent nation following separation from the Federation of Malaysia, Singapore has taken bold steps in implementing ambitious developement policies and h...

G. Y. P. Yong

1985-01-01

27

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

Microsoft Academic Search

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

Hiren Sarkar

2007-01-01

28

The Effects of Academic Optimism on Student Academic Achievement in Alabama  

ERIC Educational Resources Information Center

The purpose of the research was to determine the effects of academic optimism on student academic achievement through measuring the individual and collective effects of academic emphasis, collective efficacy, and faculty trust in clients. Data for this study were obtained from the School Academic Optimism Scale and the reading section of the…

Bevel, Raymona King

2010-01-01

29

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

ERIC Educational Resources Information Center

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

McGuigan, Leigh; Hoy, Wayne K.

2006-01-01

30

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

31

Local growth could be achieved using local innovation  

SciTech Connect

In a recent column I mentioned that sometimes the solutions to economic growth for our area—and even the nation—are closer than we might think. At the latest Tri-Cities Research District Speaker Series event, this message was reinforced by two commercialization managers at Pacific Northwest National Laboratory. Peter Christensen and Eric Lund are two in a team of seven experts that help connect companies with technologies developed at PNNL. Sometimes they license those technologies to established companies with existing product lines and sometimes they see entirely new companies form around the newly acquired technology’s product potential.

Madison, Alison L.

2010-12-19

32

Moderating Effects of Achievement Striving and Situational Optimism on the Relationship between Ability and Performance Outcomes of College Students.  

ERIC Educational Resources Information Center

Examined to what extent students' ability, achievement striving, and situational optimism influence performance outcomes and the interactive effects of ability and achievement striving, as well as ability and situational optimism, on student performance outcomes. Found that achievement striving and situational optimism may be as important as…

Nonis, Sarath A.; Wright, David

2003-01-01

33

Induction of gene expression in bacteria at optimal growth temperatures.  

PubMed

Traditional temperature-sensitive systems use either heat shock (40-42 °C) or cold shock (15-23 °C) to induce gene expression at temperatures that are not the optimal temperature for host cell growth (37 °C). This impacts the overall productivity and yield by disturbing cell growth and cellular metabolism. Here, we have developed a new system which controls gene expression in Escherichia coli at more permissive temperatures. The temperature-sensitive cI857-P L system and the classic lacI-P lacO system were connected in series to control the gene of interest. When the culture temperature was lowered, the thermolabile cI857 repressor was activated and blocked the expression of lacI from P L. Subsequently, the decrease of LacI derepressed the expression of gene of interest from P lacO . Using a green fluorescent protein marker, we demonstrated that (1) gene expression was tightly regulated at 42 °C and strongly induced by lowering temperature to 25-37 °C; (2) different levels of gene expression can be induced by varying culture temperature; and (3) gene expression after induction was sustained until the end of the log phase. We then applied this system in the biosynthesis of acetoin and demonstrated that high yield and production could be achieved using temperature induction. The ability to express proteins at optimal growth temperatures without chemical inducers is advantageous for large-scale and industrial fermentations. PMID:23271670

Jiang, Xinglin; Zhang, Haibo; Yang, Jianming; Liu, Min; Feng, Hongru; Liu, Xiaobin; Cao, Yujin; Feng, Dexin; Xian, Mo

2013-06-01

34

Achieving and documenting closure in plant growth facilities  

NASA Astrophysics Data System (ADS)

As NASA proceeds with its effort to develop a Controlled Ecological Life Support System (CELSS) that will provide life support to crews during long duration space missions, it must address the question of facility and system closure. Here we discuss the concept of closure as it pertains to CELSS and describe engineering specifications, construction problems and monitoring procedures used in the development and operation of a closed plant growth facility for the CELSS program. A plant growth facility is one of several modules required for a CELSS. A prototype of this module at Kennedy Space Center is the large (7m tall × 3.5m diameter) Biomass Production Chamber (BPC), the central facility of the CELSS Breadboard Project. The BPC is atmospherically sealed to a leak rate of approximately 5% of its total volume per 24 hours. This paper will discuss the requirements for atmospheric closure in this facility, present CO2 and trace gas data from initial tests of the BPC with and without plants, and describe how the chamber was sealed atmospherically. Implications that research conducted in this type of facility will have for the CELSS program are discussed.

Knott, William M.; Sager, John C.; Wheeler, Ray

35

Achieving and documenting closure in plant growth facilities  

NASA Technical Reports Server (NTRS)

As NASA proceeds with its effort to develop a Controlled Ecological Life Support System (CELSS) that will provide life support to crews during long duration space missions, it must address the question of facility and system closure. The concept of closure as it pertains to CELSS and engineering specifications, construction problems and monitoring procedures used in the development and operation of a closed plant growth facility for the CELSS program are described. A plant growth facility is one of several modules required for a CELSS. A prototype of this module at Kennedy Space Center is the large (7m tall x 3.5m diameter) Biomass Production Chamber (BPC), the central facility of the CELSS Breadboard Project. The BPC is atmospherically sealed to a leak rate of approximately 5 percent of its total volume per 24 hours. This paper will discuss the requirements for atmospheric closure in the facility, present CO2 and trace gas data from initial tests of the BPC with and without plants, and describe how the chamber was sealed atmospherically. Implications that research conducted in this type of facility will have for the CELSS program are discussed.

Knott, W. M.; Sager, John C.; Wheeler, Ray

1992-01-01

36

Optimization of lamp spectrum for vegetable growth  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

37

Academic Optimism of High School Teachers: Its Relationship to Organizational Citizenship Behaviors and Student Achievement  

ERIC Educational Resources Information Center

The purpose of this study is to build on an emergent research base for academic optimism by testing the construct and its relationship to student achievement and organizational citizenship behaviors in schools in a sample of public high schools. All participants in this study were full-time teachers, guidance counselors, and other full-time…

Wagner, Charles A.; DiPaola, Michael F.

2011-01-01

38

Use of a Batch Reactive Distillation with Dynamic Optimization Strategy to Achieve Industrial Grade Ethyl Acetate  

NASA Astrophysics Data System (ADS)

Industrial grade ethyl acetate is available with minimum purity of 85.0%. It is mostly produced by an ethanol esterification in a distillation process on both batch and continuous modes. However, researches on high purity production with short operating time are rarely achieved. Therefore, the objective in this work is to study an approach to produce ethyl acetate of 90.0% by 8 hours using a batch reactive distillation column. Based on open-loop simulations, the distillation with constant reflux ratio cannot achieve the product specification. Thus, the dynamic optimization strategy is proposed to handle this problem. For the process safety--preventing the dried column and fractured, a minimum reflux ratio must be determined in advance and then an optimal reflux profile is calculated to achieve optimal product yield. Simulation results show that the industrial grade ethyl acetate can be produced by the dynamic optimization programming with two or more time intervals. Besides, the increasing of time intervals can produce more distillate product.

Konakom, Kwantip; Saengchan, Aritsara; Kittisupakorn, Paisan; Mujtaba, Iqbal M.

2011-08-01

39

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

40

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

41

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

PubMed Central

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

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

2014-01-01

42

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.

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

2014-01-01

43

Achievement Goals and Achievement during Early Adolescence: Examining Time-Varying Predictor and Outcome Variables in Growth-Curve Analysis  

ERIC Educational Resources Information Center

The present study advances understanding of (a) the development of achievement goals, (b) the changing association of achievement goals and achievement over time, and (c) the implications of changes in achievement goals for changes in achievement over time. African American and European American adolescents' (N = 588) achievement goals and…

Shim, S. Serena; Ryan, Allison M.; Anderson, Carolyn J.

2008-01-01

44

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

45

Optimal Government Spending and Taxation in Endgenous Growth Models  

Microsoft Academic Search

This paper analyzes optimal spending, tax and financial policies in models of endogenous growth where public spending is productive. We extend previous work in four directions. First, we analyze optimal policies when the government is allowed to borrow and lend, rather than being restricted to run a balanced budget in every period. Second, we develop a model with a separate

Giancarlo Corsetti; Nouriel Roubini

1996-01-01

46

Optimal Taxation in a Stochastic Endogenous Growth Model with Congestion  

Microsoft Academic Search

In this paper the impacts of income and consumption taxes are analyzed within a model of stochastic endogenous growth with congestion. It is shown that the optimal amount of governmental input diminishes with uncertainty and that the optimal financing depends on the relation between the degrees of rivalry and relative risk aversion. Due to the insurance effect associated with the

Ingrid Ott; Susanne Soretz

2002-01-01

47

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

PubMed Central

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 consistently achieved 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; R2 = 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 Gy 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.; Pugh, Thomas J.; Swanson, David A.; Bruno, Teresa L.; Bolukbasi, Yasemin; Frank, Steven J.

2014-01-01

48

Optimal Conditions for the Mycelial Growth of Coprinus comatus Strains  

PubMed Central

The principal objective of this study was to acquire basic data regarding the mycelial growth characteristics for the artificial cultivation of Coprinus comatus. 12 URP primers were employed to evaluate the genetic relationships of C. comatus, and the results were divided into three groups. Among six kinds of mushroom media, MYP medium was selected as the most favorable culture medium for C. comatus. The optimal temperature and pH ranges for the mycelial growth of C. comatus were 23~26? and pH 6~8, respectively. The carbon and nitrogen sources for optimal mycelial growth were sucrose and tryptone, respectively.

Lee, Yun-Hae; Liu, Jun-Jie; Ju, Young-Cheol

2009-01-01

49

Relative importance of birth size and postnatal growth for women's educational achievement  

Microsoft Academic Search

Background: Child undernutrition, commonly measured by growth failure, is associated with functional disadvantages later in life. Aims: To assess relationships between child growth and women's educational achievement (EA). Study design and subjects: Women from four ladino Guatemalan villages were measured as children (1969–1977) and again at ages 20–29 years (1996–1999). The anthropometric measurements analyzed were weight, length, and head circumference

Haojie Li; Ann M. DiGirolamo; Huiman X. Barnhart; Aryeh D. Stein; Reynaldo Martorell

2004-01-01

50

On the Achievable Efficiency-Fairness Tradeoff in Utility-Optimal MAC Protocols  

NASA Astrophysics Data System (ADS)

We use the network utility maximization (NUM) framework to create an efficient and fair medium access control (MAC) protocol for wireless networks. By adjusting the parameters in the utility objective functions of NUM problems, we control the tradeoff between efficiency and fairness of radio resource allocation through a rigorous and systematic design. In this paper, we propose a scheduling-based MAC protocol. Since it provides an upper-bound on the achievable performance, it establishes the optimality benchmarks for comparison with other algorithms in related work.

Lee, Jang-Won; Chiang, Mung; Calderbank, A. Robert

51

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

52

Clean air with economic growth: Optimization modeling  

NASA Astrophysics Data System (ADS)

Conflicts between the goals of having clean air and economic development are widespread. This paper discusses the conceptual and mathematical development of a linear programming optimization model and an interative solution procedure to determine optimal economic development strategies to promote employment subject to various contexts which limit air pollution carrying capacity. Three cases are formulated: (1) maximizing employment subject to ambient concentration constraints, (2) maximizing employment subject to emissions constraints, and (3) minimizing emissions subject to employment constraints. Empirical relationships using Census and pollutant inventory data describe a conceptual urban system, so that indirect and induced impacts of development strategies are also included. The modeling incorporates both point and nonpoint sources, and is shown to be adaptable for nonreactive emissions.

Muschett, F. Douglas

1982-03-01

53

A Longitudinal Assessment of Early Acceleration of Students in Mathematics on Growth in Mathematics Achievement  

ERIC Educational Resources Information Center

Early acceleration of students in mathematics (in the form of early access to formal abstract algebra) has been a controversial educational issue. The current study examined the rate of growth in mathematics achievement of accelerated gifted, honors, and regular students across the entire secondary years (Grades 7-12), in comparison to their…

Ma, X.

2005-01-01

54

Optimization of growth hormone therapy in growth hormone deficient children  

Microsoft Academic Search

Conclusion  It is obvious that the results published so far as well as the present preliminary data do not answer many questions regarding\\u000a the optimal therapeutic regimen in GH deficiency. In particular, long-term follow-up must be organized to evaluate efficacy\\u000a and safety of GH therapy not only in GHD but also for the “new” indications such as Turner syndrome, short stature

Muinck De Keizer-Schrama

1991-01-01

55

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

56

Simultaneous achievement of drag reduction and heat transfer augmentation in wall turbulence by optimal control theory  

NASA Astrophysics Data System (ADS)

The analogy concept between momentum and heat transfer, which is based upon the similarity between the Navier-Stokes and energy transport equations, has been widely used for analyzing turbulent transport phenomena. This fact implies inherent difficulty in enhancing heat transfer with pumping power reduced or not increased as much as heat transfer. We consider a fully developed turbulent channel flow with uniform heat generation in the fluid, so that the averaged transport equations have an identical form. The problem thus posed offers the most difficult challenge to achieve dissimilar momentum and heat transfer. Even under such a difficult condition, we demonstrate that the dissimilar control is possible if we exploit the continuity constraint on the velocity field. In order to optimize the control input, i.e., wall blowing/suction, the optimal control theory developed by Bewley et al. (2001) is applied. By defining the cost functional as a weighted sum of the intensity of the wall blowing/suction and the analogy factor, i.e., the ratio of wall heat flux and skin friction, the analogy factor increases more than double beyond that in the uncontrolled flow. It is also found that the resultant optimized control input exhibits a downstream traveling wave-like property.

Yamamoto, Akira; Hasegawa, Yosuke; Kasagi, Nobuhide

2011-11-01

57

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.

Geary, David C.

2011-01-01

58

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

59

Gender differences in achieving optimal lipid goals in patients with coronary artery disease.  

PubMed

To investigate gender differences in lipid goal attainment, we conducted a retrospective analysis of outpatient electronic health records from a large cardiology practice from September 2008 to September 2009. The most recent lipid profile and lipid-lowering medications and doses were extracted from electronic medical record. We identified 9,950 patients with coronary artery disease of whom 3,366 (34%) were women. Women were less likely to achieve a low-density lipoprotein (LDL) cholesterol goal of <70 mg/dl compared with men (30.6% vs 38.4%, p <0.001) and less likely to achieve a non-high-density lipoprotein cholesterol goal of <100 mg/dl (37.1% vs 48.2%, p <0.001). Irrespective of age, women were less likely to achieve their LDL cholesterol goals. Compared with men, women were more likely to be on no statin (16.9% vs 11.6%, p <0.001) or any lipid-lowering therapy (12.8% vs 7.8%, p <0.001) and less likely to be on high-potency statin (14.9% vs 18.0%, p <0.001) or combination therapy (22.2% vs 30.1%, p <0.001). There exists a major difference in the use of lipid-lowering therapy between men and women with coronary artery disease. In conclusion, women with coronary artery disease are prescribed insufficient doses of statins and combination lipid-lowering therapy and are less likely to achieve their optimal LDL and non-high-density lipoprotein cholesterol goals. PMID:24698458

Victor, Brett M; Teal, Valerie; Ahedor, Lilian; Karalis, Dean G

2014-05-15

60

Optimization of nutritional requirements for mycelial growth and sporulation of entomogenous fungus Aschersonia aleyrodis Webber  

PubMed Central

The objective of the present study was to investigate the optimal nutritional requirements for mycelial growth and sporulation of entomopathogenic fungus Aschersonia aleyrodis Webber by orthogonal layout methods. Herein the order of effects of nutrient components on mycelial growth was tryptone > Ca2+ > soluble starch > folacin, corresponding to the following optimal concentrations: 1.58% Soluble Starch, 3.16% Tryptone, 0.2 mmol l-1 Ca2+ and 0.005% Folacin. The optimal concentration of each factors for sporulation was 1.16% lactose, 0.394% tryptone, 0.4 mmol l-1 Fe2+ and 0.00125% VB1, and the effects of medium components on sporulation were found to be in the order lactose > VB1 > Fe2+ > tryptone. Under the optimal culture conditions, the maximum production of mycelial growth achieved 20.05 g l-1 after 7 days of fermentation, while the maximum spore yield reached 5.23 ×1010 spores l-1 after 22 days of cultivation. This is the first report on optimization of nutritional requirements and design of simplified semi-synthetic media for mycelial growth and sporulation of A. aleyrodis.

Zhu, Yanping; Pan, Jieru; Qiu, Junzhi; Guan, Xiong

2008-01-01

61

Optimization of nutritional requirements for mycelial growth and sporulation of entomogenous fungus Aschersonia aleyrodis Webber.  

PubMed

The objective of the present study was to investigate the optimal nutritional requirements for mycelial growth and sporulation of entomopathogenic fungus Aschersonia aleyrodis Webber by orthogonal layout methods. Herein the order of effects of nutrient components on mycelial growth was tryptone > Ca(2+) > soluble starch > folacin, corresponding to the following optimal concentrations: 1.58% Soluble Starch, 3.16% Tryptone, 0.2 mmol l(-1) Ca(2+) and 0.005% Folacin. The optimal concentration of each factors for sporulation was 1.16% lactose, 0.394% tryptone, 0.4 mmol l(-1) Fe(2+) and 0.00125% VB1, and the effects of medium components on sporulation were found to be in the order lactose > VB1 > Fe(2+) > tryptone. Under the optimal culture conditions, the maximum production of mycelial growth achieved 20.05 g l(-1) after 7 days of fermentation, while the maximum spore yield reached 5.23 ×10(10) spores l(-1) after 22 days of cultivation. This is the first report on optimization of nutritional requirements and design of simplified semi-synthetic media for mycelial growth and sporulation of A. aleyrodis. PMID:24031305

Zhu, Yanping; Pan, Jieru; Qiu, Junzhi; Guan, Xiong

2008-10-01

62

Reconstruction After Complex Facial Trauma: Achieving Optimal Outcome Through Multiple Contemporary Surgeries.  

PubMed

INTRODUCTION: Major facial trauma injuries often require complex repair. Traditionally, the reconstruction of such injuries has primarily utilized only free tissue transfer. However, the advent of newer, contemporary procedures may lead to potential reconstructive improvement through the use of complementary procedures after free flap reconstruction. METHODS: An 18-year-old male patient suffered a major left facial degloving injury resulting in soft-tissue defect with exposed zygoma, and parietal bone. Multiple operations were undertaken in a staged manner for reconstruction. A state-of-the-art free anterolateral thigh (ALT) perforator flap and Medpor implant reconstruction of the midface were initially performed, followed by flap debulking, lateral canthopexy, midface lift with redo canthopexy, scalp tissue expansion for hairline reconstruction, and epidermal skin grafting for optimal skin color matching. RESULTS: Over a follow-up period of 2 years, a good and impressive reconstructive result was achieved through the use of multiple contemporary reconstructive procedures following an excellent free ALT flap reconstruction. CONCLUSIONS: Multiple staged reconstructions are essential in producing an optimal outcome in this complex facial injury that would likely not have been produced through a 1-stage traditional free flap reconstruction. Utilizing multiple, sequential contemporary surgeries may substantially improve outcome through the enhancement and refinement of results based on possibly the best initial soft-tissue reconstruction. PMID:23486138

Jaiswal, Rohit; Pu, Lee L Q

2013-03-11

63

Growth optimization procedures for the phytopathogen Xylella fastidiosa.  

PubMed

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

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

2003-02-01

64

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

Microsoft Academic Search

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

Sebastian Morris; Rakesh Basant

65

Optimization of Dairy Sludge for Growth of Rhizobium Cells  

PubMed Central

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

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

2013-01-01

66

Executive functioning in individuals with a history of ASDs who have achieved optimal outcomes.  

PubMed

Executive functioning (EF) is examined among children and adolescents once diagnosed with an autism spectrum disorder (ASD), but who no longer meet diagnostic criteria. These individuals have average social and language skills, receive minimal school support and are considered to have achieved "optimal outcomes" (OOs). Since residual impairments in these individuals might be expected in deficits central to autism, and in developmentally advanced skills, EF was examined in 34 individuals who achieved OOs, 43 individuals with high-functioning autism (HFA), and 34 typically developing (TD) peers. Groups were matched on age (M = 13.49), gender, and nonverbal IQ (NVIQ) but differed on verbal IQ (VIQ; HFA < TD, OO). On direct assessment, all three groups demonstrated average EF; however, the OO and HFA groups exhibited more impulsivity and less efficient planning and problem-solving than the TD group, and more HFA participants exhibited below average inhibition than did OO and TD participants. Parent-report measures revealed average EF among the OO and TD groups; however, the OO group exhibited more difficulty than the TD group on set-shifting and working memory. HFA participants demonstrated more difficulty on all parent-reported EF domains, with a clinical impairment in attention-shifting. Results suggest that EF in OO appears to be within the average range, even for functions that were impaired among individuals with HFA. Despite their average performance, however, the OO and TD groups differed on measures of impulsivity, set-shifting, problem-solving, working memory, and planning, suggesting that the OO group does not have the above-average EF scores of the TD group despite their high-average IQs. PMID:23731181

Troyb, Eva; Rosenthal, Michael; Eigsti, Inge-Marie; Kelley, Elizabeth; Tyson, Katherine; Orinstein, Alyssa; Barton, Marianne; Fein, Deborah

2014-07-01

67

Achieving profitable growth in E and P: New strategies, business model  

SciTech Connect

Major changes in the oil and gas environment during the last decade and a half have necessitated significant course corrections in upstream business strategies. Exogenous factors such as privatization and the opening of new opportunity areas have caused significant shifts in company strategies to drive growth, while lingering low commodity prices have applied continuous pressure to reduce costs. Successful upstream players have changed their strategies--from frontier exploration to development/production new ventures and on to gas and power plays--and built the capabilities necessary to achieve profitable growth. Moreover, these companies have adopted a new business model, an organization paradigm based on process-driven networks of business units, accountability and pay-for-performance, empowered multidisciplinary teams, and best practice sharing.

Cavoulacos, P. [Booz, Allen and Hamilton, Washington, DC (United States); Deffarges, E. [Booz, Allen and Hamilton, San Francisco, CA (United States)

1997-05-26

68

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

NASA Astrophysics Data System (ADS)

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

von Secker, Clare Elaine

69

Using Routing Optimization in Next Generation Network to Achieve High QoS  

Microsoft Academic Search

This paper deals with the routing optimization in IPV6 networks. It's the key processes of traffic engineering and network planning. Routing optimization provides a means to balance the traffic load in the network with the goal to improve the quality of service. The main objective of our routing optimization procedures is the minimization of the end-to-end delay, which is the

El-Bahlul Fgee; Abdoelbari Elalo; William J. Phillips; A. Elhounie

2010-01-01

70

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

71

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

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

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

74

Achievable rate region and optimality of multi-hop wireless 802.11-scheduled networks  

Microsoft Academic Search

This paper describes a methodology to find the achievable rate region for any static wireless multi-hop network with 802.11 scheduling. To do so, we first characterize the achievable edge-rate region, that is, the set of edge rates that are achievable on the given topology. This requires a careful consideration of the inter-dependence among nearby edges, since neighboring edges collide with

Apoorva Jindal; Konstantinos Psounis

2008-01-01

75

Optimal control synthesis in therapy of solid tumor growth  

NASA Astrophysics Data System (ADS)

A mathematical model of tumor growth therapy is considered. The total amount of a drug is bounded and fixed. The problem is to choose an optimal therapeutic strategy, i.e., to choose an amount of the drug permanently affecting the tumor that minimizes the number of tumor cells by a given time. The problem is solved by the dynamic programming method. Exact and approximate solutions to the corresponding Hamilton-Jacobi-Bellman equation are found. An error estimate is proved. Numerical results are presented.

Bratus', A. S.; Chumerina, E. S.

2008-06-01

76

Organic transistor and inverter based on assembly of organic nanowires achieved by optimizing surface morphology  

NASA Astrophysics Data System (ADS)

We have demonstrated that assemblies of organic nanowires can be grown on Si and SiO2 substrates by controlling growth parameters. At higher growth temperatures, anisotropic growth dominates over isotropic growth, resulting in surface morphologies consisting of nanowire-like elongated grains. These elongated grains provide better ?-? stacking, leading to higher carrier mobility and better performance of organic transistors. Using this approach, we have demonstrated organic inverter using complementary semiconducting materials, p-type copper phthalocyanine and n-type copper hexadecafluoro phthalocyanine. These results indicate that small organic molecule-based nanowires are promising candidates for future organic based microelectronics.

Yadav, Sarita; Sharma, Akanksha; Ghosh, Subhasis

2013-03-01

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.

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

2012-01-01

78

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.

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

2011-01-01

79

Modeling of urban growth using cellular automata (CA) optimized by Particle Swarm Optimization (PSO)  

NASA Astrophysics Data System (ADS)

In this paper, two satellite images of Tehran, the capital city of Iran, which were taken by TM and ETM+ for years 1988 and 2010 are used as the base information layers to study the changes in urban patterns of this metropolis. The patterns of urban growth for the city of Tehran are extracted in a period of twelve years using cellular automata setting the logistic regression functions as transition functions. Furthermore, the weighting coefficients of parameters affecting the urban growth, i.e. distance from urban centers, distance from rural centers, distance from agricultural centers, and neighborhood effects were selected using PSO. In order to evaluate the results of the prediction, the percent correct match index is calculated. According to the results, by combining optimization techniques with cellular automata model, the urban growth patterns can be predicted with accuracy up to 75 %.

Khalilnia, M. H.; Ghaemirad, T.; Abbaspour, R. A.

2013-09-01

80

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

ERIC Educational Resources Information Center

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

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

2013-01-01

81

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

82

Optimal growth of Central and East Pacific ENSO events  

NASA Astrophysics Data System (ADS)

Central Pacific (CP)-type and Eastern Pacific (EP)-type El Niño and the Southern Oscillation (ENSO) events are investigated using linear inverse modeling. Optimal initial conditions and growth rates for CP or EP ENSO events are identified explicitly using a CP or EP ENSO norm. The dominant difference in initial conditions that lead to CP and EP ENSO events is the role of the second empirical orthogonal function of tropical sea surface temperature, which represents the Pacific Meridional Mode (PMM). Optimal initial conditions for CP-type ENSO events include warm SST anomalies in the central subtropical Pacific (a characteristic of the PMM) while optimal initial conditions for EP-type ENSO events are focused in the eastern equatorial Pacific and Southern Hemisphere subtropics along about 25°S. Thermocline anomalies differ in initial structures and in their influence on SST for CP and EP events. Results point to different roles of the PMM and thermocline variations in the evolution of CP and EP ENSO events.

Vimont, Daniel J.; Alexander, Michael A.; Newman, Matthew

2014-06-01

83

Gabapentin for the treatment of painful diabetic neuropathy: dosing to achieve optimal clinical response  

Microsoft Academic Search

ObjectiveTo determine whether gabapentin titrated to achieve clinical effect (? 50% reduction in pain; 900—3,600 mg\\/day) provides superior efficacy to a commonly prescribed fixed-dose (900 mg\\/day) in subjects with PDN.MethodsIn Latin America, an open-label trial randomised 339 subjects with PDN to gabapentin, 900 mg\\/day, for seven weeks (n=170), or to 900—3,600 mg\\/day titrated over four weeks to achieve clinical effect,

Francisco J Gómez-Pérez; Armando Perez-Monteverde; Osvaldo Nascimento; Pablo Aschner; Marino Tagle; Klaus Fichtner; Ponni Subbiah; Elizabeth M Mutisya; Bruce Parsons

2004-01-01

84

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

ERIC Educational Resources Information Center

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

Burgess, Melissa L.

2010-01-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

86

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

Microsoft Academic Search

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

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

2011-01-01

87

Optimization of the monolayer growth in adsorption-desorption processes.  

PubMed

Kinetics of the deposition process of dimers in the presence of desorption is studied by Monte Carlo method on a one-dimensional lattice. The aim of this work is to investigate how do various temporal dependencies of the desorption rate hasten or slow down the deposition process. The growth of the coverage ?(t) above the jamming limit to its steady-state value ?(?) is analyzed when the desorption probability P(des) decreases both stepwise and linearly (continuously) over a certain time domain. We report a numerical evidence that the time needed for a system to reach the given coverage ? can be significantly reduced if P(des) decreases in time. Finally, a self-consistent optimization procedure, when the probability P(des) depends on the current coverage density ?(t), is formulated and tested. The present model reproduces qualitatively the densification kinetics and the memory effects of vibrated granular materials. Our results suggest that the process of vibratory compaction of granular materials can be optimized by using a time dependent intensity of external excitations. PMID:24329238

Živkovi?, S; Jakši?, Z M; Lon?arevi?, I; Budinski-Petkovi?, Lj; Vrhovac, S B; Beli?, A

2013-11-01

88

Need for optimizing catalyst loading for achieving affordable microbial fuel cells.  

PubMed

Microbial fuel cell (MFC) technology is a promising technology for electricity production together with simultaneous water treatment. Catalysts play an important role in deciding the MFC performance. In most reports, effect of catalyst - both type and quantity is not optimized. In this paper, synthesis of nanorods of MnO2-catalyst particles for application in Pt-free MFCs is reported. The effect of catalyst loading i.e., weight ratio, with respect to conducting element and binder has been optimized by employing large number of combinations. Using simple theoretical model, it is shown that too high (or low) concentration of catalysts result in loss of MFC performance. The operation of MFC has been investigated using domestic wastewater as source of bio-waste for obtaining real world situation. Maximum power density of ?61 mW/m(2) was obtained when weight ratio of catalyst and conducting species was 1:1. Suitable reasons are given to explain the outcomes. PMID:23735791

Singh, Inderjeet; Chandra, Amreesh

2013-08-01

89

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.

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

2013-01-01

90

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

Microsoft Academic Search

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

Pankaj Doshi; K. V. Venkatesh

1998-01-01

91

Achieving high lipid productivity of a thermotolerant microalga Desmodesmus sp. F2 by optimizing environmental factors and nutrient conditions.  

PubMed

The optimal conditions for cultivating the thermotolerant lipid-rich microalga Desmodesmus sp. F2 to achieve maximal lipid productivity were determined in this study. The conditions were light intensity, 700?mol/m(2)s; temperature, 35°C; cultivation nitrogen source, nitrate; initial nitrogen level, 6.6mM nitrogen. Carbon dioxide (2.5%, 0.2 vvm) was pumped into the cultures continuously. In the pre-optimized conditions, the maximal lipid productivity of this microalga was 113mg/L/d, which was raised to 263mg/L/d in the optimized conditions. This level of lipid productivity of microalgae is the highest ever reported in the literature. Fatty acid composition of the lipid produced by Desmodesmus sp. F2 in the optimal conditions was determined, in which C16 and C18 species accounted for 95% of the fatty acids. Saturated, monounsaturated and polyunsaturated fatty acids accounted for 38.9%, 33.1% and 22.6%, respectively. Based on the analysis, this lipid quality makes it a good feedstock for biodiesel production. PMID:24491294

Ho, Shih-Hsin; Chang, Jo-Shu; Lai, Yen-Ying; Chen, Ching-Nen Nathan

2014-03-01

92

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

93

Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications.  

PubMed

Although vegetarian diets are generally lower in total fat, saturated fat, and cholesterol than are nonvegetarian diets, they provide comparable levels of essential fatty acids. Vegetarian, especially vegan, diets are relatively low in alpha-linolenic acid (ALA) compared with linoleic acid (LA) and provide little, if any, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Clinical studies suggest that tissue levels of long-chain n-3 fatty acids are depressed in vegetarians, particularly in vegans. n-3 Fatty acids have numerous physiologic benefits, including potent cardioprotective effects. These effects have been demonstrated for ALA as well as EPA and DHA, although the response is generally less for ALA than for EPA and DHA. Conversion of ALA by the body to the more active longer-chain metabolites is inefficient: < 5-10% for EPA and 2-5% for DHA. Thus, total n-3 requirements may be higher for vegetarians than for nonvegetarians, as vegetarians must rely on conversion of ALA to EPA and DHA. Because of the beneficial effects of n-3 fatty acids, it is recommended that vegetarians make dietary changes to optimize n-3 fatty acid status. PMID:12936959

Davis, Brenda C; Kris-Etherton, Penny M

2003-09-01

94

Distorting Value Added: The Use of Longitudinal, Vertically Scaled Student Achievement Data for Growth-Based, Value-Added Accountability  

ERIC Educational Resources Information Center

Longitudinal, student performance-based, value-added accountability models have become popular of late and continue to enjoy increasing popularity. Such models require student data to be vertically scaled across wide grade and developmental ranges so that the value added to student growth/achievement by teachers, schools, and districts may be…

Martineau, Joseph A.

2006-01-01

95

Defining an Urban Growth Strategy Which will Achieve Maximum Travel Demand Reduction and Access Opportunity Enhancement.  

National Technical Information Service (NTIS)

This report investigated the potential for directing the growth of an urban region so that the evolving urban form contributes to high levels of access opportunity with minimum travel requirements. Measures of total travel, accessibility, and spatial equi...

J. W. Clark

1974-01-01

96

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

97

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

PubMed

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

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

2011-08-01

98

Using Growth Rate of Reading Fluency to Predict Performance on Statewide Achievement Tests  

ERIC Educational Resources Information Center

Federal legislation has prescribed the increased use of statewide achievement tests as the culmination of a student's knowledge and ability at the end of a grade level; however, schools need to be able to predict those who are at-risk of performing poorly on these high-stakes tests. Three studies served to identify a means of predicting statewide…

Hinkle, Rachelle Whittaker

2011-01-01

99

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

ERIC Educational Resources Information Center

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

Goosby, Bridget J.; Cheadle, Jacob E.

2009-01-01

100

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

101

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

102

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

103

Optimal reactive oxygen species concentration and p38 MAP kinase are required for coronary collateral growth.  

PubMed

Reactive oxygen species (ROS) are implicated in coronary collateral growth (CCG). We evaluated the requirement for ROS in human coronary artery endothelial cell (HCAEC) tube formation, CCG in vivo, and signaling (p38 MAP kinase) by which ROS may stimulate vascular growth. The flavin-containing oxidase inhibitor diphenyleneiodonium (DPI) or the superoxide dismutase inhibitor diethyldithiocarbamate (DETC) blocked vascular endothelial growth factor-induced HCAEC tube formation in Matrigel. We assessed the effect of DPI and DETC on CCG in a rat model of repetitive ischemia (RI) (40 s left anterior descending coronary artery occlusion every 20 min for 2 h 20 min, 3 times/day, 10 days). DPI or DETC was given intraperitoneally, or the NAD(P)H oxidase inhibitor apocynin was given in drinking water. Collateral-dependent flow (measured by using microspheres) was expressed as a ratio of normal and ischemic zone flows. In sham-operated rats, collateral flow in the ischemic zone was 18 +/- 6% of normal zone; in the RI group, collateral flow in the ischemic zone was 83 +/- 5% of normal zone. DPI prevented the increase in collateral flow after RI (25 +/- 4% of normal zone). Similar results were obtained with apocynin following RI (32 +/- 7% of that in the normal zone). DETC achieved similar results (collateral flow after RI was 21 +/- 2% of normal zone). DPI and DETC blocked RI-induced p38 MAP kinase activation in response to vascular endothelial growth factor and RI. These results demonstrate a requirement for optimal ROS concentration in HCAEC tube formation, CCG, and p38 MAP kinase activation. p38 MAP kinase inhibition prevented HCAEC tube formation and partially blocked RI-induced CCG (42 +/- 7% of normal zone flow), indicating that p38 MAP kinase is a critical signaling mediator of CCG. PMID:17308014

Rocic, Petra; Kolz, Christopher; Reed, Ryan; Potter, Barry; Chilian, William M

2007-06-01

104

Optimal Production Growth for the Machine Loading Problem.  

National Technical Information Service (NTIS)

This paper investigates a production growth logistics system for the machine loading problem (generalized transportation model), with a linear cost structure and minimum levels on total machine hours (resources) and product types (demands). An algorithm i...

V. Balachandran

1975-01-01

105

Optimization of Environmental Conditions to Maximize Carbon Dioxide Sequestration Through Algal Growth.  

National Technical Information Service (NTIS)

The micro-alga Chlorella vulgaris was cultivated under a variety of environmental conditions in various culture media solutions to optimize growth rate and biomass productivity. Efforts during this work investigated growth at the micro-scale in an air-lif...

K. M. Karcher

2010-01-01

106

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

Microsoft Academic Search

We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and\\u000a polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid for robust cell growth and high PHA production. The 3-hydroxyvalerate content in the\\u000a resulting PHA depended on the proportion of propionate initially present in the growth medium. The proportion of

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

2010-01-01

107

Thermal Optimization of Growth and Quality in Protein Crystals  

NASA Technical Reports Server (NTRS)

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

Wiencek, John M.

1996-01-01

108

Optimizing control of Fe catalysts for carbon nanotube growth.  

PubMed

One must control the size distribution of catalyst Fe nano-particles (NPs) very carefully if one is to have any chance of growing "super-aligned" carbon nanotube (CNT) forests which can be spun directly into yarns and pulled directly into long sheets. Control of the Fe Nps size is important during all phases, including: the catalyst deposition, annealing and forest growth. As a result, it is important to understand how NPs are affected by various experimental factors as well as how those catalyst NPs then cause the growth of the forests. This paper focuses on two key experimental factors: The as-deposited thickness of the Fe catalyst film and the use of hydrogen gas (H2) during anneal and growth. We found that the sheet resistance (Rs) of as-deposited Fe films is directly related to the average film thickness and can be used to estimate whether the films can catalyze the growth of super-aligned forests. The height of the CNT forests decrease with decreasing Rs, but only slowly. More importantly, CNTs grown on the largest and the smallest Rs films are less aligned. Instead, they are more curled and wavy due to the Fe NP dynamics. The use of Hydrogen (H2) affects the formation of Fe NPs from the as-deposited film as well as their composition during the forest growth. We find that the addition of H2 to a CNT forest growth process at 680 degrees C (C2H2/He [30/600 sccm]) increases the CNT alignment substantially. H2 can also reduce iron-oxides which otherwise would impede the formation of NPs. As a result, H2 has multiple roles: besides its chemical reactivity, H2 is important for catalyst reconstruction into NPs having a proper size distribution as well as surface density. PMID:22966629

Jung, Dae Woong; Lee, Kyung H; Kim, Jae Hak; Burk, Dorothea; Overzet, Lawrence J; Lee, Gil Sik; Kong, Seong Ho

2012-07-01

109

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

110

A portfolio approach to endogenous growth: equilibrium and optimal policy  

Microsoft Academic Search

This paper develops a portfolio approach to modeling endogenous growth in continuous time that is especially suitable for addressing fiscal and financial issues in policy design. The analysis focuses on the equilibrium relationship between fiscal and financial policy, rates of return and wealth allocation. We analyze two models. The first is based on the Arrow-Romer model with increasing returns and

Giancarlo Corsetti

1997-01-01

111

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.

2013-01-01

112

Growth hormone deficiency: optimizing therapy and new issues.  

PubMed

Growth Hormone Deficiency (GHD) with low circulating IGF1 requires replacement therapy. Paradoxically, it remains a controversial issue in a large part of patients, those considered as having isolated GHD of the idiopathic milder form. Challenges remain in this area in spite of intensive and sometimes controversial studies. This is true for the diagnosis of the milder forms (also called partial GHD), for the assessment of the growth response and the evaluation of final height benefit. In addition the cost-benefit issue should not be ignored. Therefore, the author tried to review data relevant to the evaluation of GH secretion which even now remains largely arbitrary. The growth response, which is the primary therapeutic goal in these children should also be carefully discussed as reported in recent papers. Focusing on individual responses should help adjusting individual dosage within the standard recommended doses, but one should also remember that there are no long term safety data for non conventional high rhGH doses. More studies are needed. Response to treatment during the first year may in the future help select the patients who are prone to the benefit of long term rhGH therapy. Basic rules for indication and progression of treatment are proposed in children with various forms of GHD. It is also remarkable that the present safety data are all coming from several post-marketing studies. This means that long term independent studies are now required as recombinant growth hormone remains the most appropriate and efficient therapy when permanent GH deficiency is fully documented. PMID:22037859

Rappaport, Raphaël

2012-02-01

113

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

PubMed

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

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

2013-11-13

114

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

PubMed Central

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

2013-01-01

115

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

ERIC Educational Resources Information Center

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…

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

2006-01-01

116

Optimized medium for clonal growth of human microvascular endothelial cells with minimal serum  

Microsoft Academic Search

Summary  An optimized basal nutrient medium, MCBD 131, has been developed that supports clonal growth of human microvascular endothelial\\u000a cells (HMVEC) with as little as 0.7% dialyzed fetal bovine serum (dFBS) when also supplemented with 10 ng\\/ml epidermal growth\\u000a factor (EGF) and 1 ?g\\/ml hydrocortisone. An extensive initial survey of available media showed that MCDB 402, a medium optimized\\u000a for low-serum

Ann Knedler; Richard G. Ham

1987-01-01

117

Growth schedule of Xanthium canadense : Does it optimize the timing of reproduction?  

Microsoft Academic Search

The effects of nutrition on the timing of reproductive initiation of a short-day annual plant Xanthium canadense (cocklebur) were examined with the following hypotheses in mind: If the plant always follows an optimal growth schedule, low-nutrient plants will initiate reproductive growth earlier than high-nutrient plants. On the other hand, if the plant flowers in response to photoperiodic stimuli, both plants

H. Sugiyama; T. Hirose

1991-01-01

118

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

PubMed

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

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

2000-01-20

119

Generalized Self-Efficacy Expectancies and Optimism as Predictors of Growth Group Outcomes.  

ERIC Educational Resources Information Center

Examined optimism, generalized self-efficacy, and interactions between these variables, along with member expectancies for group, as predictors of growth group outcomes. Results based on student responses (N=19) indicate that the ability of initial expectancies to predict outcome depended on the level of generalized self-efficacy. (RJM)

Lightsey, Owen Richard, Jr.

1997-01-01

120

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

Microsoft Academic Search

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

T. LECHIANCOLE; A. RICCIARDI; E. PARENTE

121

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

SciTech Connect

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

Krishnan, Manoj Kumar; Nieplocha, Jarek

2005-04-26

122

An Optimized Design of Anode Shape Based on Artificial Neural Network for Achieving Highest X-ray Yield in Plasma Focus Device  

NASA Astrophysics Data System (ADS)

In this paper, an optimized design of anode shape in order to achieve highest X-ray yield in a plasma focus device filled with nitrogen gas based on artificial neural networks (ANNs) is presented. Multi-layer perceptron neural network structure with the back-propagation algorithm is used for the training of the proposed model. The model has achieved good agreement with the training data and has yielded satisfactory generalization. This shows that the ANN model is an accurate and reliable approach to predict the highest X-ray yield in plasma focus devices.

Hayati, M.; Roshani, G. H.; Abdi, H.; Rezaei, A.; Mahtab, M.

2013-08-01

123

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

124

Optimization of selection for growth in Menz Sheep while minimizing inbreeding depression in fitness traits  

PubMed Central

The genetic trends in fitness (inbreeding, fertility and survival) of a closed nucleus flock of Menz sheep under selection during ten years for increased body weight were investigated to evaluate the consequences of selection for body weight on fitness. A mate selection tool was used to optimize in retrospect the actual selection and matings conducted over the project period to assess if the observed genetic gains in body weight could have been achieved with a reduced level of inbreeding. In the actual selection, the genetic trends for yearling weight, fertility of ewes and survival of lambs were 0.81 kg, –0.00026% and 0.016% per generation. The average inbreeding coefficient remained zero for the first few generations and then tended to increase over generations. The genetic gains achieved with the optimized retrospective selection and matings were highly comparable with the observed values, the correlation between the average breeding values of lambs born from the actual and optimized matings over the years being 0.99. However, the level of inbreeding with the optimized mate selections remained zero until late in the years of selection. Our results suggest that an optimal selection strategy that considers both genetic merits and coancestry of mates should be adopted to sustain the Menz sheep breeding program.

2013-01-01

125

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

126

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

127

A Capacity-Achieving Precoding Scheme Based on Channel Inversion Regularization with Optimal Power Allocation for MIMO Broadcast Channels  

Microsoft Academic Search

Zero-forcing (ZF) precoding can asymptotically achieve the sum-rate capacity offered by the dirty paper coding (DPC) in a multiple-input multiple-out (MIMO) broadcast (BC) channel in the limit of the large number of users K. However, its performance is degraded for relatively small K, e.g., Kles100, partly due to the excessive transmit power penalty when the channel matrix of selected user

Yang Xu; Tho Le-ngoc

2007-01-01

128

Optimization of Vi capsular polysaccharide production during growth of Salmonella enterica serotype Typhi Ty2 in a bioreactor  

Microsoft Academic Search

Vi capsular polysaccharide is synthesized during growth of Salmonella typhi Ty2 and is spontaneously released from the bacterial cells into the culture medium during culture. Vi production was dependent on cell growth and the greater the cell mass the greater the production of Vi. Using fed batch culture to optimize bacterial growth resulted is an increase in cell mass and

Hyun Jang; Yeon Kyung Yoon; Jeong Ah Kim; Hyo Seung Kim; So Jung An; Jin Ho Seo; Changfa Cui; Rodney Carbis

2008-01-01

129

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

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.

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

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

132

Native Language Proficiency, English Literacy, Academic Achievement, and Occupational Attainment in Limited-English-Proficient Students: A Latent Growth Modeling Perspective  

ERIC Educational Resources Information Center

The hypothesis that native language (L1) proficiency promotes English acquisition and overall academic achievement, a key theoretical assumption underlying bilingual education, was tested using latent growth modeling of data from 899 limited-English-proficient (LEP) eighth graders who were followed for 12 years in the National Education…

Guglielmi, R. Sergio

2008-01-01

133

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

134

Effect of Retention in First Grade on Children's Achievement Trajectories over 4 Years: A Piecewise Growth Analysis Using Propensity Score Matching  

ERIC Educational Resources Information Center

The authors investigated the relatively short-term and longer term effects of grade retention in 1st grade on the growth of mathematics and reading achievement over 4 years. The authors initially identified a large multiethnic sample (n = 784) of children who were below the median in literacy at school entrance. From this sample, the authors…

Wu, Wei; West, Stephen G.; Hughes, Jan N.

2008-01-01

135

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

136

Optimal Culture Conditions for Mycelial Growth and Exo-polymer Production of Ganoderma applanatum.  

PubMed

The effect of fermentation parameters and medium composition on the simultaneous mycelial growth and exo-polymer production from submerged cultures of Ganoderma applanatum was investigated in shake-flask cultures. The optimum initial pH for mycelial growth and exo-polymer production was 5.0 and 6.0, respectively. The optimum temperature was 25? and the optimum inoculum content was 3.0% (v/v). The optimal carbon and nitrogen sources were glucose and corn steep powder, respectively. After 12 days fermentation under these conditions, the highest mycelial growth was 18.0 g/l and the highest exo-polymer production was 3.9 g/l. PMID:23983515

Jeong, Yong-Tae; Jeong, Sang-Chul; Yang, Byung-Keun; Islam, Rezuanul; Song, Chi-Hyun

2009-06-01

137

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

138

Monitoring Plasmodium falciparum Growth and Development by UV Flow Cytometry Using an Optimized Hoechst-Thiazole Orange Staining Strategy  

PubMed Central

The complex life cycle of Plasmodium falciparum (Pf) makes it difficult to limit infections and reduce the risk of severe malaria. Improved understanding of Pf blood-stage growth and development would provide new opportunities to evaluate and interfere with successful completion of the parasite’s life cycle. Cultured blood stage Pf was incubated with Hoechst 33342 (HO) and thiazole orange (TO) to stain DNA and total nucleic acids, respectively. Correlated HO and TO fluorescence emissions were then measured by flow cytometry. Complex bivariate data patterns were analyzed by manual cluster gating to quantify parasite life cycle stages. The permutations of viable staining with both reagents were tested for optimal detection of parasitized RBC (pRBC). Pf cultures were exposed to HO and TO simultaneously to achieve optimal staining of pRBC and consistent quantification of early and late stages of the replicative cycle (rings through schizonts). Staining of Pf nucleic acids allows for analysis of parasite development in the absence of fixatives, lysis, or radioactivity to enable examination of erythrocytes from parasite invasion through schizont rupture using sensitive and rapid assay procedures. Investigation of the mechanisms by which anti-malarial drugs and antibodies act against different Pf lifecycle stages will be aided by this cytometric strategy.

Grimberg, Brian T.; Erickson, John J.; Sramkoski, R. Michael; Jacobberger, James W.; Zimmerman, Peter A.

2012-01-01

139

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

140

Effectiveness of setting numerical targets in the surgical training of residents: a trial to achieve an optimal balance.  

PubMed

During the past 10 years, residency training in otorhinolaryngology-head and neck surgery (ORL-HNS) in Japan, especially at university hospitals, has emphasized subspecialization, resulting in insufficiencies in basic surgical techniques with an extreme bias toward acquiring subspecialty surgical case experience. To address this problem, we developed a target-oriented program intended to achieve a more balanced approach to surgical training and performed a 1-year trial of the program at the Jikei University School of Medicine. Fourteen residents with 1 to 4 years of ORL-HNS experience completed the trial. Each resident's competencies in six basic surgical procedures were assessed on the basis of the number of cases handled by the resident, and each resident's case selection bias after implementation of the target-oriented training was examined. The case selection bias in the trial group residents was reduced and their balance in case experience was shown to be improved in comparison with that in control group residents who were trained in the conventional way. In addition, opinion surveys of the participants and supervising otorhinolaryngologists (trainers) indicated that they felt that the new training system had been effective in improving the balance in case experience and improving motivation, and creating greater awareness of training goals and progress. PMID:24464636

Komiya, Kiyoshi; Saito, Momoko; Sakurai, Yuika; Kojima, Hiromi; Takase, Kozo

2014-01-01

141

Growth optimization toward low angle incidence microchannel epitaxy of GaN using ammonia-based metal-organic molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

Growth optimization toward low angle incidence microchannel epitaxy (LAIMCE) of GaN was accomplished using ammonia-based metal-organic molecular beam epitaxy (NH3-based MOMBE). Firstly, the [NH3]/[trimethylgallium (TMG)] ratio (R) dependence of selective GaN growth was studied. The growth temperature was set at 860 °C while R was varied from 5 to 200 with precursors being supplied parallel to the openings cut in the SiO2 mask. The selectivity of the growth was superior for all R, because TMG and NH3 preferably decompose on the GaN film. The formation of {112¯0}GaN or {112¯2}GaN sidewalls and (0001)GaN surface were observed by the change in R. The intersurface diffusion of Ga adatoms was also changed by a change in R. Ga adatoms migrate from the sidewalls to the top at R lower than 50, whereas the migration weakened with R greater than 100. Secondly, LAIMCE was optimized by changing the growth temperature. Consequently, 6 ?m wide lateral overgrowth in the direction of precursor incidence was achieved with no pit after etching by H3PO4, which was six times wider than that in the opposite direction.

Lin, Chia-Hung; Abe, Ryota; Uchiyama, Shota; Maruyama, Takahiro; Naritsuka, Shigeya

2012-08-01

142

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

PubMed

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

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

2007-01-01

143

Aluminum incorporation in AlxGa1-xN-layers and implications for growth optimization  

NASA Astrophysics Data System (ADS)

AlxGa1-xN-layers are applied in various devices based on group-III-nitride semiconductors. Crystalline quality, composition and morphology need to be controlled by properly adjusting growth processes. Here we report on AlxGa1-xN-growth by low pressure MOVPE on planar surfaces of sapphire with focus on Al-incorporation. The solid Al-composition xAl depends critically on growth parameters for constant gas phase compositions. The strongest effect is found for total pressure: Al is efficiently incorporated only at pressures lower than 50 mbar. This can be understood mainly as a result of prereactions in the gas phase involving TMAl and NH 3 which has been discussed earlier in a theoretical paper of the Jensen group [T.G. Mihopoulos, V. Gupta, K.F. Jensen, J. Crystal Growth 195 (1998) 733]. In this publication we compare the predictions of this work with our data and implications for growth optimization.

Rossow, U.; Fuhrmann, D.; Litte, T.; Retzlaff, T.; Hoffmann, L.; Bremers, H.; Hangleiter, A.

2007-01-01

144

Optimized growth and dielectric properties of barium titanate thin films on polycrystalline Ni foils  

NASA Astrophysics Data System (ADS)

Barium titanate (BTO) thin films were deposited on polycrystalline Ni foils by using the polymer assisted deposition (PAD) technique. The growth conditions including ambient and annealing temperatures were carefully optimized based on thermal dynamic analysis to control the oxidation processing and interdiffusion. Crystal structures, surface morphologies, and dielectric performance were examined and compared for BTO thin films annealed under different temperatures. Correlations between the fabrication conditions, microstructures, and dielectric properties were discussed. BTO thin films fabricated under the optimized conditions show good crystalline structure and promising dielectric properties with inr ~ 400 and tan ? < 0.025 at 100 kHz. The data demonstrate that BTO films grown on polycrystalline Ni substrates by PAD are promising in device applications.

Liang, Wei-Zheng; Ji, Yan-Da; Nan, Tian-Xiang; Huang, Jiang; Zeng, Hui-Zhong; Du, Hui; Chen, Chong-Lin; Lin, Yuan

2012-06-01

145

Apparatus and method for achieving growth-etch deposition of diamond using a chopped oxygen-acetylene flame  

NASA Astrophysics Data System (ADS)

A novel apparatus and method for the cyclic growth-etch deposition of diamond on a substrate by flame chemical vapor deposition (CVD) is developed. The cyclic growth-etch diamond deposition is accomplished by placing a suitable substrate to be coated under a CVD flame and providing a disk or face plate or other shapes having one or more teeth (or holes) wherein upon rotation of the disk, or face plate, or other shape, the teeth attached to the disk, or face plate, or other shape obstruct the path of the CVD flame from contacting the substrate at a desired time scale of T(growth) and t(cycle) to produce high quality FWHM of 1-3.5/cm diamond.

Thorpe, Thomas P.; Weimer, Ronald A.

1994-11-01

146

Magnetosome Assembling and Optimization of Growth Conditions of the Magnetospirillum Magneticum AMB-1 Strain  

Microsoft Academic Search

Growth conditions of Magnetospirillum magneticum AMB-1 were optimized by orthogonal experimental design. When culturing conditions were chosen with ferric quinine 0.02 mmol\\/L, 75% volume, pH 6.7 and 25degC, the OD600 values reached 0.440 (1.166times109 cells\\/ml). AMB-1 cells were all collected by magnet before inoculation. After magnetic enrichment and cultivation for several times, Cmag values of AMB-1 reached 1.9- 2.0 steadily.

Yuhong Zhang; Shiying Ren; Hongqing Wu; Tian Xiao

2008-01-01

147

Soybean meal and wheat flour, proper dietary protein sources for optimal growth of snail ( Semisulcospira coreana )  

Microsoft Academic Search

A 10-week feeding experiment was conducted to determine the proper dietary protein source for optimal growth performance of\\u000a juvenile snails, Semisulcospira coreana. Sixteen isonitrogenous (31% crude protein) and isocaloric (4.2 kcal\\/g DM) experimental diets (designated as FM, F-FM, SBM,\\u000a F-SBM, WF, F-WF, SSM, F-SSM, SCR, F-SCR, UP, F-UP, FWP, F-FWP, MIX and F-MIX) were formulated to contain 41% fish meal, 42%

Minh Anh Pham; Gyu-Deok Hwang; Yi-Oh Kim; Joo-Young Seo; Sang-Min Lee

2010-01-01

148

Optimal policies aimed at stabilization of populations with logistic growth under human intervention.  

PubMed

This work examines both positive and negative impacts that economic growth may have on the ecological dynamics and stability of a single biological species. Local extinction of the species may force the social planner to implement defensive expenditures aimed at conservation of the species population by means of habitat protection. The latter may lead to an ecological equilibrium that will be different from the natural equilibrium that would have arisen in the absence of human intervention. Moreover, the existence of such equilibrium is formally demonstrated and its stability properties are revised. Additionally, optimal-choice decision policies are constructed on the basis of Pontryagin's maximum principle. Under such policies together with initial abundance of the species, the growth trajectories will move the system towards the fixed point of maximum species abundance. PMID:22960017

Cruz-Rivera, Erica; Vasilieva, Olga

2013-02-01

149

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

150

Optical spectroscopy and optimal crystal growth of some Cr4+-doped garnets  

NASA Astrophysics Data System (ADS)

This paper describes the growth of single crystals of Cr4+ -doped Y3 Ga5 O12 (YGG) and Y3 Al5 O12 (YAG). Control of melt composition and post-growth annealing yields material that contains optimal concentrations of Cr4+ ions in distorted tetrahedral sites normally occupied by Ga3+ ions in YGG and Al3+ ions in YAG. Both Cr4+ -doped garnets exhibit strong visible and near-infrared absorption bands with peak cross sections of order 10-18 -10-19 cm2 and emit into vibronically broadened but weakly allowed 3 B2 (3 T2 )icons/Journals/Common/to" ALT="to" ALIGN="TOP"/> 3 B1 (3 A2 ) transitions. Nonradiative decay is more efficient in YGG than in YAG as a consequence of the slightly reduced energy gap against radiative decay in the Ga-based garnet.

Henderson, B.; Gallagher, H. G.; Han, T. P. J.; Scott, M. A.

2000-02-01

151

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

152

Growth dominant co-precipitation process to achieve high coercivity at room temperature in CoFe2O4 nanoparticles  

Microsoft Academic Search

Applications of CoFe2O4 are limited due to the lack of synthesis technique to produce monodispersed, single domain and high coercivity (Hc) nanoparticles. Here, we describe the growth dominant co-precipitation process to achieve high Hc, with moderate magnetization at room temperature (RT) in CoFe2O4 nanoparticles. It is well known that the particle size is closely related to the relative interdependence between

C. N. Chinnasamy; B. Jeyadevan; O. Perales-Perez; K. Shinoda; K. Tohji; A. Kasuya

2002-01-01

153

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

154

Acropetal leaflet initiation of Eschscholzia californica is achieved by constant spacing of leaflets and differential growth of leaf.  

PubMed

In compound leaves, leaflet primordia are initiated directionally along the lateral sides. Our understanding of the molecular basis of leaflet initiation has improved, but the regulatory mechanisms underlying spatio-temporal patterns remain unclear. In this study, we investigated the mechanisms of acropetal (from the base to the tip) progression of leaflet initiation in Eschscholzia californica. We established an ultraviolet-laser ablation system to manipulate compound-leaf development. Local ablation at the leaflet incipient site generated leaves with asymmetric morphology. In the majority of cases, leaflets that were initiated on the ablated sides shifted apically. Finite time-course observation revealed that the timing of leaflet initiation was delayed, but the distance from the leaf tip did not decrease. These results were suggestive of the local spacing mechanism in leaflet initiation, whereby the distance from the leaf tip and adjacent pre-existing leaflet determines the position of leaflet initiation. To understand how such a local patterning mechanism generates a global pattern of successive leaflet initiation, we assessed the growth rate gradient along the apical-basal axis. Our time-course analysis revealed differential growth rates along the apical-basal axis of the leaf, which can explain the acropetal progression of leaflet initiation. We propose that a leaflet is initiated at a site where the distances from pre-existing leaflets and the leaf tip are sufficient. Furthermore, the differential growth rate may be a developmental factor underlying the directionality of leaflet initiation. PMID:24718490

Ikeuchi, Momoko; Igarashi, Hisako; Okada, Kiyotaka; Tsukaya, Hirokazu

2014-07-01

155

Optimized invertase expression and secretion cassette for improving Yarrowia lipolytica growth on sucrose for industrial applications.  

PubMed

Yarrowia lipolytica requires the expression of a heterologous invertase to grow on a sucrose-based substrate. This work reports the construction of an optimized invertase expression cassette composed of Saccharomyces cerevisiae Suc2p secretion signal sequence followed by the SUC2 sequence and under the control of the strong Y. lipolytica pTEF promoter. This new construction allows a fast and optimal cleavage of sucrose into glucose and fructose and allows cells to reach the maximum growth rate. Contrary to pre-existing constructions, the expression of SUC2 is not sensitive to medium composition in this context. The strain JMY2593, expressing this new cassette with an optimized secretion signal sequence and a strong promoter, produces 4,519 U/l of extracellular invertase in bioreactor experiments compared to 597 U/l in a strain expressing the former invertase construction. The expression of this cassette strongly improved production of invertase and is suitable for simultaneously high production level of citric acid from sucrose-based media. PMID:24061566

Lazar, Zbigniew; Rossignol, Tristan; Verbeke, Jonathan; Crutz-Le Coq, Anne-Marie; Nicaud, Jean-Marc; Robak, Ma?gorzata

2013-11-01

156

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

157

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

158

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

159

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

NASA Technical Reports Server (NTRS)

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

Tiller, Michael M.

1995-01-01

160

Controlled growth of CNT in mesoporous AAO through optimized conditions for membrane preparation and CVD operation  

NASA Astrophysics Data System (ADS)

Anodic aluminium oxide (RAAO) membranes with a mesoporous structure were prepared under strictly controlling experimental process conditions, and physically and chemically characterized by a wide range of experimental techniques. Commercial anodic aluminium oxide (CAAO) membranes were also investigated for comparison. We demonstrated that RAAO membranes have lower content of both water and phosphorus and showed better porosity shape than CAAO. The RAAO membranes were used for template growth of carbon nanotubes (CNT) inside its pores by ethylene chemical vapour deposition (CVD) in the absence of a catalyst. A composite material, containing one nanotube for each channel, having the same length as the membrane thickness and an external diameter close to the diameter of the membrane holes, was obtained. Yield, selectivity and quality of CNTs in terms of diameter, length and arrangement (i.e. number of tubes for each channel) were optimized by investigating the effect of changing the experimental conditions for the CVD process. We showed that upon thermal treatment RAAO membranes were made up of crystallized allotropic alumina phases, which govern the subsequent CNT growth, because of their catalytic activity, likely due to their Lewis acidity. The strict control of experimental conditions for membrane preparation and CNT growth allowed us to enhance the carbon structural order, which is a critical requisite for CNT application as a substitute for copper in novel nano-interconnects.

Ciambelli, P.; Arurault, L.; Sarno, M.; Fontorbes, S.; Leone, C.; Datas, L.; Sannino, D.; Lenormand, P.; Le Blond Du Plouy, S.

2011-07-01

161

Optimal life schedule with stochastic growth in age-size structured models: theory and an application.  

PubMed

Reproduction timing is one of the most important factors for the life history because it is closely related to subsistence of species. On the other hand, ecological demographers recently noted the effects of environmental stochasticity on the population dynamics by using linear demographic models because stochasticity reduces the population growth rate. Linear demographic models are generally composed of reproduction timing, several life history traits and stochasticity. The stochasticity is generated by twofold stochasticity, that is, internal and external stochasticities. In transition matrix models, the internal stochasticity gives a species a set of transition probabilities to other states, whereas the external stochasticity annually variegates the value of these transition probabilities. If the population vector has only the internal stochasticity, it satisfies a partial differential equation, in which it is described by a stochasticity in body-size growth rate. In this paper, we focus on the stochasticity which affects the body-size growth rate under r-selection. We construct a mathematical model of stochastic life history of each individual by using a stochastic differential equation, and analyze the relationship between optimal life schedule and the population dynamics by finding Euler-Lotka equation. Then, we use the formalism of path-integral expression to the population dynamics and show that the expression is consistent with other expressions in linear demographic models. Finally, we apply our method to a simple example, and obtain a characteristic of the stochasticity which has not only negative effect on the fitness but also positive effect from our model. PMID:23391431

Oizumi, Ryo; Takada, Takenori

2013-04-21

162

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

NASA Technical Reports Server (NTRS)

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

Tumin, Anatoli; Ashpis, David E.

2003-01-01

163

Third and Final Shuttle Mission of the Isothermal Dendritic Growth Experiment Conducted: Highest Supercooling Ever Recorded Achieved  

NASA Technical Reports Server (NTRS)

Dendrites describe the treelike crystal morphology commonly assumed in metals and alloys that freeze from supercooled or supersaturated melts. There remains a high level of engineering interest in dendritic solidification because the size, shape, and orientation of the dendrites determine the final microstructure of a material. It is the microstructure that then determines the physical properties of cast or welded products. Although it is well known that dendritic growth is controlled by the transport of latent heat from the moving solid-liquid interface, an accurate and predictive model has not yet been developed. The effects of gravity-induced convection on the transfer of heat from the interface have prevented adequate testing, under terrestrial conditions, of solidification models. The Isothermal Dendritic Growth Experiment (IDGE) constituted a series of three microgravity experiments flown aboard the Space Shuttle Columbia. The apparatus was used to grow and record dendrite solidification in the absence of gravity-induced convective heat transfer, thereby producing a wealth of benchmark-quality data for testing solidification models and theories.

Glicksman, Martin E.; Malarik, Diane C.

1999-01-01

164

Optimization of marine waste based-growth media for microbial lipase production using mixture design methodology.  

PubMed

Lipase production by Staphylococcus xylosus and Rhizopus oryzae was investigated using a culture medium based on a mixture of synthetic medium and supernatants generated from tuna by-products and Ulva rigida biomass. The proportion of the three medium components was optimized using the simplex-centroid mixture design method (SCMD). Results indicated that the experimental data were in good agreement with predicted values, indicating that SCMD was a reliable method for determining the optimum mixture proportion of the growth medium. Maximal lipase activities of 12.5 and 23.5 IU/mL were obtained with a 50:50 (v:v) mixture of synthetic medium and tuna by-product supernatant for Staphylococcus xylosus and Rhizopus oryzae, respectively. The predicted responses from these mixture proportions were also validated experimentally. PMID:24350480

Sellami, Mohamed; Kedachi, Samiha; Frikha, Fakher; Miled, Nabil; Ben Rebah, Faouzi

2013-01-01

165

Optimization studies for the growth of Pb(1-x)Sn(x)Te in space  

NASA Technical Reports Server (NTRS)

A study of the effects of convection on the quality of crystals grown by the Bridgman technique has been initiated. This study is to provide a basis for the utilization of the low-gravity environment furnished by the Space Shuttle in the development of crystals with a better quality than obtainable under terrestrial conditions. A series of ground-based studies has been started with the objective to optimize the results of Shuttle experiments. A description is presented of preliminary results of some of these studies. Attention is given to a thermo-solutal convection analysis, the development of a technique for interface demarcation, the growth of Pb(1-x)Sn(x)Te crystals, thermophysical property measurements, and solutal diffusion coefficients.

Crouch, R. K.; Fripp, A. L.; Debnam, W. J., Jr.; Clark, I. O.; Carlson, F. M.

1983-01-01

166

Nuclear Symbiosis - A Means to Achieve Sustainable Nuclear Growth while Limiting the Spread of Sensititive Nuclear Technology  

SciTech Connect

Global growth of nuclear energy in the 21st century is creating new challenges to limit the spread of nuclear technology without hindering adoption in countries now considering nuclear power. Independent nuclear states desire autonomy over energy choices and seek energy independence. However, this independence comes with high costs for development of new indigenous fuel cycle capabilities. Nuclear supplier states and expert groups have proposed fuel supply assurance mechanisms such as fuel take-back services, international enrichment services and fuel banks in exchange for recipient state concessions on the development of sensitive technologies. Nuclear states are slow to accept any concessions to their rights under the Non-Proliferation Treaty. To date, decisions not to develop indigenous fuel cycle capabilities have been driven primarily by economics. However, additional incentives may be required to offset a nuclear state’s perceived loss of energy independence. This paper proposes alternative economic development incentives that could help countries decide to forgo development of sensitive nuclear technologies. The incentives are created through a nuclear-centered industrial complex with “symbiotic” links to indigenous economic opportunities. This paper also describes a practical tool called the “Nuclear Materials Exchange” for identifying these opportunities.

David Shropshire

2009-09-01

167

In situ growth optimization in focused electron-beam induced deposition  

PubMed Central

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

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

2013-01-01

168

Thermal optimization of CZ bulk growth and wafer annealing for crystalline dislocation-free silicon  

NASA Astrophysics Data System (ADS)

In this article, we consider a number of questions related to the thermal optimization of 200 mm diameter Si Czochralski (CZ) single-crystal growth process using the new "Redmet-90M" puller and the rapid thermal annealing (RTA) of Si wafers cut from single crystals. The article includes results of the CZ numerical modeling of heat transfer, which takes into account the special thermal shield assemblies (with and without water cooling). The influences of various crucible rotation rates on the distribution of the azimuthal velocity of the melt and on the liquid-solid interface were also investigated. Differences in axial temperature profiles of the growing crystal were analyzed depending on whether the thermal shield was used with or without its water-cooling system and depending on the various crucible rotation rates. A numerical diffusion-recombination model of intrinsic point defects (vacancies and interstitial Si atoms), which takes into account the vacancy cluster formation, was applied for RTA optimization. Vacancy concentration, density and sizes of vacancy clusters were calculated along the thickness of a wafer. An experimental study on the defect structure in the annealed Si wafers was carried out by the light microscopy and the transmission electron microscopy. The type, density and morphology of defects in the thickness of a wafer were also analyzed. The experimental distribution of total defect density in the thickness of a wafer was compared with the calculated vacancy cluster density.

Prostomolotov, A. I.; Verezub, N. A.; Mezhennii, M. V.; Reznik, V. Ya.

2011-03-01

169

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

170

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

171

Screening of yeasts for growth on crude glycerol and optimization of biomass production.  

PubMed

Out of 113 yeast strains tested, 45 grew on pure glycerol with growth rates ranging from 0.11 to 0.37h(-1). Twenty-three strains showed specific growth rates (h(-1)), biomass production and biomass yields higher or comparable to those on glucose which suggests that crude glycerol can be utilized as carbon source in yeast cultivation for biomass production. Response surface methodology was applied to optimize crude glycerol concentration and temperature for biomass production and yield by Yarrowia lipolytica (DiSVA C 12.1), Metschnikowia sp. (DiSVA 50), Debaryomyces sp. (DiSVA 45/9), and Rhodotorula mucilaginosa (DiSVA C 7.1). A biomass concentration of 25.7g/l and a biomass yield of 0.92g/g (Y/Xglyc) was obtained with Y. lipolytica DiSVA C 12.1 and with R. mucilaginosa DiSVA C 7.1, respectively. These results demonstrate the potential use of crude glycerol as carbon source in yeast cultivation and the yeast ability to convert low-value crude glycerol to added-value products. PMID:22342043

Taccari, Manuela; Canonico, Laura; Comitini, Francesca; Mannazzu, Ilaria; Ciani, Maurizio

2012-04-01

172

Development of an optimal bacterial medium based on the growth inhibition assay with Vibrio fischeri.  

PubMed

Chronic toxicity level of chemicals to bacteria can depend on composition and concentration of medium ingredients. This was demonstrated by means of a growth rate inhibition test with the marine bacterium V. fischeri. In a minimal medium (following the validity criterion of achieving a least cell multiplication rate) containing only yeast extract as organic nutrient component, V. fischeri was to Cu2+ 11.9 times, to Hg2+ 3 times and to Zn2+ 2.8 times more sensitive than in the complete defined medium. Obviously yeast extract did not interfere greatly in the complexation mechanisms. The detection limits of the toxicity of Cd2+, 3,5-dichorophenol and nitrobenzene were not influenced by the substrate. PMID:10399848

Gellert, G; Stommel, A; Trujillano, A B

1999-08-01

173

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.

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

2009-01-01

174

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

PubMed

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

2009-08-01

175

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

NASA Astrophysics Data System (ADS)

The optimization of the crystal surface temperature distribution is performed for single-crystal growth in the Czochralski process. In the optimization problem, we seek an optimal solution in the sense that the index of crystalline defects is minimized while the single-crystal growth rate is maximized. In the objective function, the von Mises stress is considered a driving force that induces crystalline defects. In order to solve the optimization problem with the equality constraints given by the governing partial differential equations, the variational method is used. Based on the calculus of variations and the method of Lagrange multiplier, the Euler-Lagrange equations are derived in the form of coupled partial differential equations. They are solved by using the finite-difference method and the iterative numerical scheme proposed in this work. In order to handle inequality constraints, the penalty function method is applied. The optimal distributions of the crystal surface temperature obtained in this work may provide an insight into the optimal design of thermal surroundings, such as thermal shield configurations and heater/cooler positions.

Jeong, Ja Hoon; Kang, In Seok

2002-04-01

176

Optimization of Magnetosome Production and Growth by the Magnetotactic Vibrio Magnetovibrio blakemorei Strain MV-1 through a Statistics-Based Experimental Design  

PubMed Central

The growth and magnetosome production of the marine magnetotactic vibrio Magnetovibrio blakemorei strain MV-1 were optimized through a statistics-based experimental factorial design. In the optimized growth medium, maximum magnetite yields of 64.3 mg/liter in batch cultures and 26 mg/liter in a bioreactor were obtained.

Silva, Karen T.; Leao, Pedro E.; Abreu, Fernanda; Lopez, Jimmy A.; Gutarra, Melissa L.; Farina, Marcos; Bazylinski, Dennis A.; Freire, Denise M. G.

2013-01-01

177

Kinematics framework optimized for deformation, growth, and remodeling in vascular organs.  

PubMed

A basic tenant of constitutive theory is that phenomenological relations can be derivable from phenomenological behavior or material tests; and yet, conventional representation formulas, such as those of Rivlin and Fung, fail in this regard because of the choice of kinematical variables. Granted, with these representation formulas a particular constitutive relation may be guessed that fits data, but if the relation is non-unique and cannot be derived de novo from actual and/or hypothetical tests, then such a relation is indeterminable. The representation formula of Rivlin is indeterminable because of excessive covariance or coalignment in the kinematical variables. The representation formula of Fung is indeterminable because the incompressibility constraint is not utilized to reduce the kinematical variables a priori. The proposed kinematics framework succeeds in achieving determinability for hyperelastic materials because, primarily, the kinematical variables have minimal coalignment and dilatation and distortion are separated. Determinability is discussed and demonstrated in the context of hyperelasticity. However, any representation formula, whether it is for visco-elasticity or remodeling or etcetera, will be indeterminable when kinematical variables are highly coaligned and/or are subject to a non-reducible constraint. In other words, conventional kinematical frameworks are non-starters for experimentally determining constitutive representations for soft tissues. For the sake of determinability and/or validity of continuum models of vascular tissue, the proposed framework is needed. Moreover, this framework is optimized to simplify the balance equations for tubular structures. PMID:17717712

Criscione, John C

2008-08-01

178

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

179

Optimization of process parameters of polymer solution mediated growth of calcium carbonate nanoparticles.  

PubMed

With the advent of nanotechnology, many methods of synthesis of nanoparticles have come into practice and the 'polymer mediated growth' technique is among them. In this route, ions of one of the reactants are allowed to diffuse from an external solution into a polymer matrix where the other reactant is complexed and bound. The exact role of ionic diffusion in the formation of nanoparticles was investigated in the current study by studying the patterns of kinetics of nanoparticle formation using UV vis spectroscopy. Typically, calcium carbonate nanoparticles were formed by the aforementioned technique using polyethylene glycol solution. The particle size was calculated using Scherrer's formula on x-ray diffraction plots and was reconfirmed with field emission scanning electron microscope and transmission electron microscope images. Energy-dispersive x-ray analysis was used to study the composition and purity of the nanoparticles formed. The reactant to polymer ratio, reaction temperature and molecular weight of polyethylene glycol affected the size of the particles formed. Through this knowledge we optimized these parameters to obtain particles as small as 20 nm and confirmed that this technique can be used to control the size of nanoparticles. PMID:22922538

Biradar, Santoshkumar; Goornavar, Virupaxi; Periyakaruppan, Adaikkappan; Koehne, Jessica; Jeffers, Robert; Hall, Joseph C; Ramesh, Vani; Meyyappan, M; Ramesh, Govindarajan T

2012-09-21

180

Differential stability of TATA box binding proteins from archaea with different optimal growth temperatures  

NASA Astrophysics Data System (ADS)

The TATA box binding protein (TBP) is involved in promoter recognition, the first step of transcription initiation. TBP is universally conserved and essential in archaea and eukaryotes. In archaea, TBPs have to be stable and to function in species that cover an extremely wide range of optimal growth temperatures (OGTs), from below 0 °C to more than 100 °C. Thus, the archaeal TBP family is ideally suited to study the evolutionary adaptation of proteins to an extremely wide range of temperatures. We characterized the thermostability of one mesophilic and one thermophilic TBP by infrared spectroscopy. Transition temperatures ( Tms) of thermal unfolding have been determined using TBPs from Methanosarcina mazei (OGT 37 °C) and from Methanothermobacter thermautotrophicus (OGT 65 °C). Furthermore, the influence of protein and salt concentration on thermostability has been characterized. Together with previous studies, our results reveal that the Tms of archaeal TBPs are closely correlated with the OGTs of the respective species. Noteworthy, this is also true for the TBP from M. mazei representing the first characterized TBP from a mesophilic archaeon. In contrast, the only characterized eukaryotic TBP of the mesophilic plant Arabidopsis thaliana has a Tm more than 40 °C above the OGT.

Kopitz, Annette; Soppa, Jörg; Krejtschi, Carsten; Hauser, Karin

2009-09-01

181

Early diagnosis and treatment referral of children born small for gestational age without catch-up growth are critical for optimal growth outcomes  

PubMed Central

Approximately 10% of children born small for their gestational age (SGA) fail to show catch-up growth and may remain short-statured as adults. Despite treatment guidelines for children born SGA that recommend referral for growth hormone (GH) therapy evaluation and initiation by ages 2 to 4 years, the average age of GH treatment initiation is typically much later, at ages 7 to 9 years. Delayed referral for GH treatment is problematic as studies show younger age at GH treatment initiation in children born SGA is an independent predictor for responses such as optimal growth acceleration, normalization of prepubertal height, and most importantly, adult height (AH). This review discusses the importance and associated challenges of early diagnosis of children born SGA who fail to show catch-up growth, contrasts the recommended age of referral for these patients and the average age of GH treatment initiation, and discusses studies showing the significant positive effects of early referral and treatment with GH on AHs in short-statured children born SGA. To optimize the eventual height in short-statured SGA children who fail to manifest catch-up growth, a lowering of the average age of referral for GH therapy evaluation is needed to better align with consensus recommendations for SGA management. The importance of increasing parental and physician awareness that most children born SGA will do well developmentally and will optimally benefit from early initiation of GH treatment when short-statured is addressed, as is the need to shift the age of referral to better align with consensus recommendations.

2012-01-01

182

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

PubMed

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:24416012

Wahl, Anna-Sophia; Schwab, Martin E

2014-01-01

183

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.

Wahl, Anna-Sophia; Schwab, Martin E.

2014-01-01

184

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

PubMed

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

185

Optimizing Performance on Linux Clusters Using Advanced Communication Protocols: How 10+ Teraflops Was Achieved on a 8.6 Teraflops Linpack-Rated Linux Cluster  

Microsoft Academic Search

Advancements in high-performance networks (Quadrics, Infiniband or Myrinet) continue to improve the efficiency of modern clusters. However, the average application efficiency is as small fraction of the peak as the sys- tem's efficiency. This paper describes techniques for optimizing application performance on Linux clusters using Remote Memory Access communication protocols. The effectiveness of these optimizations is presented in the context

Manojkumar Krishnan; Jarek Nieplocha

186

A novel liquid medium for the efficient growth of the salmonid pathogen Piscirickettsia salmonis and optimization of culture conditions.  

PubMed

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

Henríquez, Mirtha; González, Ernesto; Marshall, Sergio H; Henríquez, Vitalia; Gómez, Fernando A; Martínez, Irene; Altamirano, Claudia

2013-01-01

187

Optimal Concentration of Hepatocyte Growth Factor for Treatment of the Aged Rat Vocal Fold  

PubMed Central

Objectives/Hypothesis: Hepatocyte Growth Factor (HGF) demonstrates beneficial properties in the treatment of aged vocal folds. However, the optimal concentration of HGF remains unknown. The purpose of the present study was to investigate the effects of HGF concentration on treatment of the aged rat vocal fold. Study Design: Prospective animal study. Methods: Seventy-five rats were studied. The rats were divided into five groups and received serial injections of HGF in 10?l of phosphate-buffered saline (PBS) at the following concentrations: 10 ng/10 ?l, 50 ng/10 ?l, 100 ng/10 ?l, 200 ng/10 ?l, or control (PBS only). Alcian blue staining was performed to investigate hyaluronan (HA), and immunohistochemistry (IHC) was performed to investigate collagen type I and III. Gene expression of hyaluronic acid synthase (HAS) ?1, ?2 matrix metalloproteinases (MMP) ?2, ?9, and procollagen I, and III were also investigated using reverse transcriptase polymerase chain reaction (RT-PCR). Results: Histological analyses revealed increased HA and decreased collagen type I in rats receiving injections of HGF at 100 ng/10 ?l. Results were supported by RT-PCR revealing upregulated expression of HAS-2, decreased expression of procollagen I, and a significant increase of MMP-9 mRNA in rats receiving HGF at 100 ng/10 ?l. Conclusions: We report the first in vivo concentration study of HGF for treatment of the aged vocal fold. Results revealed desirable biochemical effects of HGF at 100 ng/10 ?l. These data will be used to provide immediate direction to programmatic efforts aimed at examining future applications of HGF for treatment of the aged vocal fold.

Suehiro, Atsushi; Wright, Harry; Rousseau, Bernard

2011-01-01

188

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

189

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

PubMed

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

190

Optimal growth conditions and main features of GaAs single crystals for solar cell technology - A review  

NASA Astrophysics Data System (ADS)

An evaluation is made of the state-of-the-art for each of the principal techniques of GaAs single crystal bulk growth, with attention to correlations between crystal properties and growing method. The two growth methods are the Czochralski and Horizontal Bridgman systems. On the basis of an examination of the optimum properties of GaAs solar-grade substrates, a critical discussion is conducted on growth parameters, doping procedures, and defect structures for the crystals obtained. An effort is made to identify the optimal conditions which yield improved solar cell-grade GaAs. Electrical characteristics improvements are related to the lowering of deep and shallow level backgrounds, facilitating higher mobility and diffusion length.

Fornari, R.

1985-02-01

191

Growth Hormone, Glutamine, and an Optimal Diet Reduces Parenteral Nutrition in Patients With Short Bowel Syndrome  

PubMed Central

Objective: To determine if growth hormone (GH) and glutamine (Gln) might allow for a reduction in parenteral nutrition (PN) in individuals with short bowel syndrome. Background Data: Following massive intestinal resection, patients frequently sustain severe nutrient malabsorption and are dependent on PN for life. GH treatment with or without Gln might allow for a reduction in PN. Methods: A prospective, double-blind, randomized, placebo-controlled clinical trial performed in 41 adults dependent on PN. Following screening, patients were admitted to an in-house facility for 6 weeks. After 2 weeks of stabilization and dietary optimization, patients were randomized to one of 3 treatment arms (1:2:2 ratio): oral Gln (30 g/day) + GH placebo (control group, n = 9), Gln placebo + GH (0.1 mg/kg per day, n = 16), or Gln + GH (n = 16). Standard criteria based on clinical and laboratory measurements were followed to determine PN volume and content. After 4 weeks of treatment, patients were discharged and monitored; GH and GH placebo were discontinued, but the diet with Gln or Gln placebo was continued for 3 months. Results: Patients receiving GH + Gln placebo + diet showed greater reductions in PN volume (5.9 ± 3.8 L/wk, mean ± SD), PN calories (4338 ± 1858 calories/wk), and PN infusions (3 ± 2 infusions/wk) than corresponding reductions in the Gln + diet group (3.8 ± 2.4 L/wk; 2633 ± 1341 calories/wk; 2 ± 1 infusions/wk, P < 0.05). Patients who received GH + Gln + diet showed the greatest reductions (7.7 ± 3.2 L/wk; 5751 ± 2082 calories/wk; 4 ± 1 infusions/wk, P < 0.001 versus Gln + diet). At the 3-month follow-up, only patients who had received GH + Gln + diet maintained significant reductions in PN (P < 0.005) compared with the Gln + diet. Conclusions: Treatment with GH + diet or GH + Gln + diet initially permitted significantly more weaning from PN than Gln + diet. Only subjects receiving GH + Gln + diet maintained this effect for at least 3 months.

Byrne, Theresa A.; Wilmore, Douglas W.; Iyer, Kishore; Dibaise, John; Clancy, Kerri; Robinson, Malcolm K.; Chang, Peter; Gertner, Joseph M.; Lautz, David

2005-01-01

192

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

ERIC Educational Resources Information Center

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

Shin, Tacksoo

2012-01-01

193

Optimal Growth in Inertia Gravity Wave Packets: Energetics, Long-Term Development, and Three-Dimensional Structure.  

NASA Astrophysics Data System (ADS)

Using a hierarchy of three models of increasing realism and complexity, and expanding on a previous study, optimal perturbations of inertia gravity wave (IGW) packets are studied with respect to several aspects. It is shown that normal modes are comparatively less able to extract energy from the IGW over finite time due to their time-invariant structure, while singular vectors (SVs) can adjust their dynamical fields flexibly so as to optimize the statically enhanced roll and Orr mechanisms by which they grow. On longer time scales, where the time dependence of the IGW packet precludes a normal-mode analysis, optimal growth is found to further amplify suitable perturbations. The propagation characteristics of these exhibit critical layer interactions for horizontal propagation directions transverse with respect to the IGW, preventing significant vertical propagation, while parallel and obliquely propagating perturbations of sufficiently long horizontal scales are found to radiate gravity waves into altitudes not directly affected by the IGW. The SVs with shorter wavelengths, as found for short optimization times, stay confined via a linear wave duct near the altitude of least static stability where they are excited. At optimization times of the order of the IGW period the leading SVs, with an energy growth by about three orders of magnitude, propagate obliquely, possibly in correspondence to previous results by others from simulations of nonlinear IGW breakdown. The three-dimensional structure of SVs shows an amplitude modulation strictly confining the perturbations also to the horizontal location of least static stability, suggesting a picture of turbulence onset in IGW packets where local patches of growing perturbations initially dominate.


Achatz, Ulrich; Schmitz, Gerhard

2006-02-01

194

Unemployment and Growth in the Long Run: An Efficiency-Wage Model with Optimal Savings  

Microsoft Academic Search

An efficiency-wage model of steady-state equilibrium with labor-augmenting technical progress is developed to explore the long-run relationship between unemployment and growth. The rate of productivity growth is either specified exogenously or determined endogenously. In both cases, we preserve key results of the Shapiro--Stiglitz efficiency-wage analysis without growth. Our model, however, also yields some striking new results. For instance, an exogenous

Richard A. Brecher; Zhiqi Chen; Ehsan U. Choudhri

2002-01-01

195

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

PubMed

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

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

2008-02-01

196

Optimization of Vi capsular polysaccharide production during growth of Salmonella enterica serotype Typhi Ty2 in a bioreactor.  

PubMed

Vi capsular polysaccharide is synthesized during growth of Salmonella typhi Ty2 and is spontaneously released from the bacterial cells into the culture medium during culture. Vi production was dependent on cell growth and the greater the cell mass the greater the production of Vi. Using fed batch culture to optimize bacterial growth resulted is an increase in cell mass and consequently Vi production. The yield of Vi obtained in fed batch culture was 415 mgl(-1), which was over three times that, obtained in batch culture. A proportion of the Vi remained cell associated in the form of a capsule and at least part of this was released from the bacterial surface by sonication. The size of the Vi polysaccharide produced was consistently high and did not change during the different phases of bacterial growth. The synthesis of Vi was also dependent upon the media components and the fermentation conditions. The presence of high concentrations of glucose at the beginning of growth inhibited the production of Vi, particularly during the stationary phase. At a concentration of 400 mM sodium phosphate the synthesis of Vi was strongly inhibited. PMID:18400326

Jang, Hyun; Yoon, Yeon Kyung; Kim, Jeong Ah; Kim, Hyo Seung; An, So Jung; Seo, Jin Ho; Cui, Changfa; Carbis, Rodney

2008-05-20

197

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

USGS Publications Warehouse

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

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

2006-01-01

198

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

SciTech Connect

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

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

2012-01-16

199

Optimization of the semiconductor-metal transition in VO2 epitaxial thin films as a function of oxygen growth pressure  

NASA Astrophysics Data System (ADS)

High quality VO2 epitaxial thin films were deposited on sapphire single crystal substrates by pulsed laser deposition and their semiconductor-to-metal transitions (SMTs) were characterized as a function of film growth conditions. Varying the oxygen pressure during deposition affected the number of oxygen vacancies, which allowed tuning of the crystal structure and phase transition properties of the VO2 films. Films grown at optimized conditions exhibited a significant resistivity drop (>104 ?-cm) across the SMT that is correlated with the strain due to oxygen vacancies. This resistivity drop is mainly accounted for by a large change in carrier density at the SMT.

Kim, H.; Charipar, N.; Osofsky, M.; Qadri, S. B.; Piqué, A.

2014-02-01

200

Optimization of growth medium for the production of spores from Bacillus thuringiensis using response surface methodology  

Microsoft Academic Search

The effects of cultivation medium compositions including tapioca, fishmeal, CaCO3 and (NH4)2SO4 for the growth of Bacillus thuringiensis YMB 96-1988 were accessed by using response surface methodology (RSM). The two-level (24-1) fractional factorial designs (FFD) which involve two concentrations of each nutrient, and the paths of steepest ascent were effective in searching for the major factors of the bacteria growth.

Bing-Lan Liu; Yew-Min Tzeng

1998-01-01

201

Optimal capacitor placement in a radial distribution system using Plant Growth Simulation Algorithm  

Microsoft Academic Search

This paper presents a new and efficient approach for capacitor placement in radial distribution systems that determine the optimal locations and size of capacitor with an objective of improving the voltage profile and reduction of power loss. The solution methodology has two parts: in part one the loss sensitivity factors are used to select the candidate locations for the capacitor

R. Srinivasas Rao; S. V. L. Narasimham; M. Ramalingaraju

2011-01-01

202

Growth condition optimization for docosahexaenoic acid (DHA) production by Moritella marina MP-1.  

PubMed

The marine organism Moritella marina MP-1 produces the polyunsaturated fatty acid docosahexaenoic acid (DHA). While the basic metabolic pathway for DHA production in this organism has been identified, the impact of growth conditions on DHA production is largely unknown. This study examines the effect of supplemental carbon, nitrogen and salts, growth temperature and media composition and pH on DHA and biomass production and the fatty acid profile. The addition of supplemental nitrogen significantly increased the overall DHA titer via an increase in biomass production. Supplemental glucose or glycerol increased biomass production, but decreased the amount of DHA per biomass, resulting in no net change in the DHA titer. Acidification of the baseline media pH to 6.0 increased DHA per biomass. Changes in growth temperature or provision of supplemental sodium or magnesium chloride did not increase DHA titer. This organism was also shown to grow on defined minimal media. For both media types, glycerol enabled more DHA production per biomass than glucose. Combination of these growth findings into marine broth supplemented with glycerol, yeast extract, and tryptone at pH?6.0 resulted in a final titer of 82±5 mg/L, a nearly eightfold increase relative to the titer of 11±1 mg/L seen in the unsupplemented marine broth. The relative distribution of other fatty acids was relatively robust to growth condition, but the presence of glycerol resulted in a significant increase in myristic acid (C14:0) and decrease in palmitic acid (C16:0). In summary, DHA production by M. marina MP-1 can be increased more than fivefold by changing the growth media. Metabolic engineering of this organism to increase the amount of DHA produced per biomass could result in additional increases in titer. PMID:23111600

Kautharapu, Kumar B; Rathmacher, John; Jarboe, Laura R

2013-04-01

203

Achieving Sustainable Growth through the Adoption of Integrated Business and Information Solutions: A Case Study of Nigerian Small & Medium Sized Enterprises  

Microsoft Academic Search

The economic growth of any country depends, to a certain degree, on the ability of the country's business community to maximize their growth potential. One of the biggest contributors from the business community of any nation, to the nation's economic development, is the small and medium sized enterprise (SME) sector. Studies have shown that SMEs and indeed, large and multi-national

204

Catch-Up Growth after Childhood-Onset Substitution in Primary Hypothyroidism: Is It a Guide towards Optimal Growth Hormone Treatment in Idiopathic Growth Hormone Deficiency?  

Microsoft Academic Search

Catch-up growth was analyzed in 20 prepubertal children with primary hypothyroidism (PH) starting treatment at an age of 4.4 (1.2–10.1) years and a height (HT) SD score (HT SDS) of –3.1 (±0.8). All patients were followed for at least 3 prepubertal years. HT velocity was 12.3 ± 2.3, 9.0 ± 1.8 and 7.5 ± 2.2 cm\\/year, and change in HT

M. B. Ranke; C. P. Schwarze; K. Mohnike; K. E. von Mühlendahl; E. Keller; H. Willgerodt; W. Kiess

1998-01-01

205

OPTIMIZING POSITION IN THE INTERIOR SOFT TRIM VALUE CHAIN TO ENSURE PROFITABLE GROWTH  

Microsoft Academic Search

This paper reviews the interaction between the global economic situation, the automotive market, the dynamics of the auto OEM\\/Tier 1 interior supplier interface, and the ability of Tier 1 suppliers to obtain profitable growth via new technologies in automotive interior trim. Europe\\/N. American differences are reviewed and specific value added strategies are identified along with current examples of the implementation

Robert Eller

206

Southern Hemisphere Annular Mode Variability and the Role of Optimal Nonmodal Growth  

Microsoft Academic Search

The southern annular mode is the leading mode of Southern Hemisphere circulation variability, the temporal evolution of which is characterized by large amplitudes and significant persistence. Previous investigators have suggested a positive feedback mechanism that explains some of this low-frequency variance. Here, a mechanism is proposed, involving transient nonmodal growths of the anomalies, that is at least as effective as

Harun A. Rashid; Ian Simmonds

2005-01-01

207

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

208

Influence of hydrodynamic conditions on growth and geometry of anodic TiO 2 nanotubes and their use towards optimized DSSCs  

Microsoft Academic Search

In the present work we grow anodic TiO 2 nanotube layers under defined hydrodynamic conditions using a rotating Ti anode. We show that hydrodynamic control can be beneficially used to achieve two main effects. First, under conditions where tube growth is controlled by diffusion (for low concentration of fluoride ions in the electrolyte), growth can significantly be accelerated (or even

R. a c Sánchez-Tovar; I. b Paramasivam; K. b Lee; P.b Schmuki

2012-01-01

209

Optimized growth of lattice-matched InAlN/GaN heterostructures by molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

A fundamental problem in the epitaxial growth of hexagonal group III/Nitride heterostructures along their c-axis is the in-plane lattice-mismatch between the binary compounds GaN, AlN and InN. This mismatch is responsible for stress and strain formation and leads in its extreme to cracking, deteriorating the optical and electrical properties of the samples. The ternary compound InxAl1-xN with x˜0.17 is expected to have an identical in-plane lattice constant as GaN. Here we report on the MBE growth of lattice-matched InxAl1-xN on thick GaN templates. Optimizing the growth conditions and systematically investigating the influence of the flux ratio between Aluminum, Indium and Nitrogen leads to high quality layers, as assessed by x-ray diffraction. The extracted full widths at half maximum of the InAlN peak in ?-2? and rocking curve scans are 190arcsec and 300arcsec respectively and the lattice-match is confirmed by reciprocal lattice mapping. Sharp, intense high-order satellite peaks as well as the occurrence of interface interferences in the x-ray diffraction spectra confirm the high crystalline quality and abrupt interfaces of short period GaN/InAlN superlattices. These simple heterostructures are preludes to more complex structures like distributed Bragg reflectors and micro cavities.

Schmult, Stefan; Siegrist, Theo; Sergent, Mike; Manfra, Mike; Molnar, Rich

2007-03-01

210

The Optimal Capital Stock and Consumption Evolution for Non Zero Consumers Growth Rate in the Framework of Ramsey Model on Finite Horizon  

NASA Astrophysics Data System (ADS)

In this paper the Ramsey optimal growth of the capital stock and consumption on finite horizon is analyzed when the growth rate of consumers is strictly positive. The main purpose is to establish the dependence of the optimal capital stock and consumption evolution on the growth rate of consumers. The analysis reveals: for any initial value k0>=0 there exists a unique optimal evolution path of length N+1 for the capital stock; if k0 is strictly positive then all the elements of the optimal capital stock evolution path are strictly positives except the last one which is zero; the optimal capital stock evolution of length N+1 starting from k0>=0 satisfies the Euler equation; the value function VN is strictly increasing, strictly concave and continuous on R+. The family of functions {VN-T}T = 0...N-1 satisfies the Bellman equation and it is the unique solution of this equation which is both continuous and satisfies the transversality condition. The Mangasarian Lemma is also satisfied. For N tending to infinity the optimal evolution path of length N of the capital stock tends to those on the infinite time horizon. For any k0>0 the value function in k0 decreases when the consumers growth rate increases.

Bonchi?, N.; Balint, ?t.

2010-09-01

211

The role of thermophysics in the design, optimization and understanding of semiconductor crystal growth in space  

NASA Technical Reports Server (NTRS)

The compound semiconductor material PbSnTe has been investigated by NASA Langley Research Center as part of the Material Processing in Space (MPS) experiment in the framework of the Space Shuttle program. The long-range goal of the research is the improving of the performance of infrared detectors for use in remote sensing experiments. Three distinct techniques will be used in the low-g environment of space: two techniques involving bulk growth from melt and a vapor growth technique. In order to establish realistic estimates of the required time for experiments and to determine the thermal gradients that will be required to avoid constitutional supercooling, the diffusion coefficients must be accurately measured, however more data especially in the vapor-solid phase relations are needed.

Crouch, R. K.; Fripp, A. L.; Debnam, W. J.; Clark, I. O.

1979-01-01

212

Statistical optimization of cultivation conditions for exopolysacchride production and mycelia growth by Stropharia rugosoannulata  

Microsoft Academic Search

Response surface methodology (RSM) was successfully applied to investigate the effect of cultivation temperature, time and\\u000a volume of media on mycelia growth, in the light of exopolysaccharide content (EPC) and dry cell weight (DCW), by the fungus\\u000a Stropharia rugosoannulata in submerged culture. The three significant factors influencing EPC and DCW were based on the results of a previous Plackett–Burman\\u000a (PB)

Bo Zhou; Le Jia; Fanyun Meng; Zhen Song; Xiaonan Liu; Peng Deng; Keming Fan

2010-01-01

213

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.

214

Optimal Control of Film Growth in Lithium-Ion Battery Packs via Relay Switches  

Microsoft Academic Search

Recent advances in lithium-ion battery modeling suggest unequal but controlled and carefully timed charging of individual cells by reduce degradation. This paper compares anode-side film formation for a standard equalization scheme versus unequal charging through switches that are controlled by deterministic dynamic programming (DDP) and DDP-inspired heuristic algorithms. A static map for film growth rate is derived from a first-principles

Scott J. Moura; Joel C. Forman; Saeid Bashash; Jeffrey L. Stein; Hosam K. Fathy

2011-01-01

215

Optimization of Inclusion Body Solubilization and Renaturation of Recombinant Human Growth Hormone from Escherichia coli  

Microsoft Academic Search

Recombinant human growth hormone (r-hGH) was expressed in Escherichia coli as inclusion bodies. In 10 h of fed-batch fermentation, 1.6 g\\/L of r-hGH was produced at a cell concentration of 25 g dry cell weight\\/L. Inclusion bodies from the cells were isolated and purified to homogeneity. Various buffers with and without reducing agents were used to solubilize r-hGH from the

Ashok K Patra; R Mukhopadhyay; R Mukhija; Anuja Krishnan; L. C Garg; Amulya K Panda

2000-01-01

216

Optimization and validation of an enzyme immunoassay for the insect growth regulator fenoxycarb  

Microsoft Academic Search

A competitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative detection of the insect growth regulator fenoxycarb. Polyclonal rabbit antisera, raised against protein conjugates of four haptenic derivatives of fenoxycarb, were utilized in immobilized antigen-based, competitive immunoassays. With ELISA systems that were both hapten- and carrier-heterologous, most antiserum titers fell in the range of 1:1000–1:30,000. Assay conditions, including concentrations

András Székács; Hong T. M Le; Ferenc Szurdoki; Bruce D Hammock

2003-01-01

217

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

218

Growth optimization and optical properties of AlGaNAs alloys  

NASA Astrophysics Data System (ADS)

The effect of Al on the surface morphology of chemical beam epitaxy grown AlGaNAs alloys is studied. Pits attributed to N clustering appearing on the dilute nitride surface become smaller, denser, and more uniformly distributed in the presence of Al. This reveals that the introduction of Al results in more homogenous N atoms spatial distribution. A growth temperature study reveals the formation of 3D structures at high temperature due to phase separation. The density of these structures decreases, while their diameter and height increase when the temperature is raised from 380 °C to 565 °C. At growth temperatures in the 380-420 °C range, the phase separation is suppressed and the growth mode is 2D. At 420 °C, the N incorporation is also maximized, making it the optimum temperature. The absorption coefficient and the bandgap of AlGaNAs alloys are extracted from transmittance measurement. A good agreement is obtained between the experimentally measured bandgap and the theoretical values calculated using the band anticrossing model. A bandgap as low as 1.22 eV was reached using Al and N concentrations of ˜15% and ˜3.4%, respectively.

Kolhatkar, Gitanjali; Boucherif, Abderraouf; Valdivia, Christopher E.; Wallace, Steven G.; Fafard, Simon; Aimez, Vincent; Arès, Richard

2014-04-01

219

Optimization of power control in the reduction of basal plane dislocations during PVT growth of 4H-SiC single crystals  

NASA Astrophysics Data System (ADS)

The influence of power control on the multiplication of basal plane dislocations (BPDs) during PVT growth of 4H-SiC single crystals was studied by numerical modeling. Three sets of different power histories during growth were tested: continuously increasing power, continuously decreasing power, and constant power. The results show that optimization of the power history control is crucial for the reduction of basal plane dislocations during growth. If only low BPD density is concerned, then constant low power is the best choice. However, if both low BPD density and high growth rate are desirable, then concave continuously increasing power is the best choice.

Gao, B.; Kakimoto, K.

2014-04-01

220

Kinetics of phase growth in Nb3Sn formation for heat treatment optimization  

SciTech Connect

The kinetics of growth and superconducting properties of Nb{sub 3}Sn are investigated as a function of the heat treatment (HT) duration and temperature for Internal Tin and Powder-in-Tube strands at 650, 700 and 750 C. For all times and temperatures, the Nb{sub 3}Sn layer thickness is measured, the critical current at 4.2 K is tested as a function of magnetic field, and the upper critical field is evaluated. Results of the layer critical current density are also shown as a function of HT duration and temperature.

Emanuela Barzi; Sara Mattafirri

2002-10-25

221

Optimization of growth and ordering of Ag nanoparticle arrays on ripple patterned alumina surfaces for strong plasmonic coupling.  

PubMed

Low-energy ion beam sputtering of alumina thin films followed by growth of metallic nanoparticles by glancing angle deposition is optimized in order to produce arrays of silver nanoparticle chains with a strong plasmonic dichroism. A systematic study is undertaken in order to establish the influence of the angle of silver deposition and the ordering of the pre-patterned rippled surface on the morphology and organization of the nanoparticles, and on their associated optical properties. High ion fluence for ripple formation and low glancing angle for metal deposition favor the formation of aligned and elongated particles with sub-nanometer gaps. Numerical simulations show that these nanoparticle arrays generate high electric field enhancements for an excitation parallel to the particle chains, and therefore can be used for surface enhanced spectroscopies. PMID:24356668

Camelio, S; Vandenhecke, E; Rousselet, S; Babonneau, D

2014-01-24

222

Growth optimization and structural analysis for ferromagnetic Mn-doped ZnO layers deposited by radio frequency magnetron sputtering  

SciTech Connect

The effect of the deposition temperature on the crystalline quality of (Zn,Mn)O is investigated in thin films prepared by radio frequency magnetron sputtering on c-plane sapphire and GaN substrates. The layers are made of a 0.5 {mu}m Mn-doped layer towards the surface on top of a 150 nm pure ZnO buffer. Depending on the deposition temperature, the layers can exhibit a columnar structure; the adjacent domains are rotated from one another by 90 deg. , putting [1010] and [1120] directions face to face. At high Mn concentration the columnar structure is blurred by the formation of Mn rich precipitates. Only one variety of domains is observed at an optimal deposition temperature of 500 deg. C: they are slightly rotated around the [0001] axis (mosaic growth) and bounded by threading dislocations.

Abouzaid, M.; Ruterana, P.; Liu, C.; Morkoc, H. [SIFCOM UMR 6176 CNRS-ENSICAEN, 6 Boulevard du Marechal Juin, 14050 Caen Cedex (France); Department of Electrical Engineering, Virginia Commonwealth University, Richmond Virginia 23284 (United States)

2006-06-01

223

Optimization of growth conditions of ZnO nano thin films by chemical double dip technique  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nano thin films have been deposited by the chemical double-dip technique using aqueous ZnSO4 and NaOH solutions. The ZnO films were characterized in terms of surface morphology by x-ray diffraction, energy-dispersive x-ray analysis (EDX), the use of a scanning electron microscope (SEM) and atomic force microscope (AFM) for surface morphology. The films exhibited a smooth morphology. The chemical states of oxygen and zinc in the ZnO nano thin films were also investigated by x-ray photoelectron spectroscopy (XPS). In the present investigations, highly textured ZnO thin films with a preferential (002)-orientation were prepared on glass substrates. The deposition conditions were optimized to obtain device-quality films for practical applications.

Anandamoorthy Vijayan, Thirukonda; Chandramohan, Rathinam; Valanarasu, Santiyagu; Thirumalai, Jagannathan; Venkateswaran, Sivasuriyan; Mahalingam, Thaiyan; Ramachandran Srikumar, Subbiah

2008-07-01

224

Network connectivity during mergers and growth: optimizing the addition of a module.  

PubMed

The principal eigenvalue ? of a network's adjacency matrix often determines dynamics on the network (e.g., in synchronization and spreading processes) and some of its structural properties (e.g., robustness against failure or attack) and is therefore a good indicator for how "strongly" a network is connected. We study how ? is modified by the addition of a module, or community, which has broad applications, ranging from those involving a single modification (e.g., introduction of a drug into a biological process) to those involving repeated additions (e.g., power-grid and transit development). We describe how to optimally connect the module to the network to either maximize or minimize the shift in ?, noting several applications of directing dynamics on networks. PMID:21797446

Taylor, Dane; Restrepo, Juan G

2011-06-01

225

Macro-level optimized deployment of an electrolyser-based hydrogen refuelling infrastructure with demand growth  

NASA Astrophysics Data System (ADS)

Hydrogen-powered vehicles are receiving a significant amount of attention due to their potential for reduced greenhouse gas emissions, increased production pathways, and the higher efficiencies of fuel cells as compared to internal combustion engines. A major obstacle to the commercialization of hydrogen vehicles is the lack of a developed hydrogen refuelling infrastructure. A cost-effective infrastructure requires a significant number of hydrogen-powered vehicles in use. A plausible solution to the 'chicken and egg' dilemma requires the development of an infrastructure prior to competitive economic viability. This article employs optimization techniques to design a public-policy-supported infrastructure at minimum cost as the number of hydrogen vehicles increases from 10 to 100,000. The specific case used is the development of an infrastructure across a major Canadian highway spanning South Ontario and Western Quebec.

Stevens, M. B.; Fowler, M. W.; Elkamel, A.; Elhedhli, S.

2008-10-01

226

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

PubMed

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

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

2010-01-01

227

Achieving Finite Element Mesh Quality via Optimization of the Jacobian Matrix Norm and Associated Quantities, Part II - A Framework for Volume Mesh Optimization and the Condition Number of the Jacobian Matrix  

SciTech Connect

Three-dimensional unstructured tetrahedral and hexahedral finite element mesh optimization is studied from a theoretical perspective and by computer experiments to determine what objective functions are most effective in attaining valid, high quality meshes. The approach uses matrices and matrix norms to extend the work in Part I to build suitable 3D objective functions. Because certain matrix norm identities which hold for 2 x 2 matrices do not hold for 3 x 3 matrices. significant differences arise between surface and volume mesh optimization objective functions. It is shown, for example, that the equivalence in two-dimensions of the Smoothness and Condition Number of the Jacobian matrix objective functions does not extend to three dimensions and further. that the equivalence of the Oddy and Condition Number of the Metric Tensor objective functions in two-dimensions also fails to extend to three-dimensions. Matrix norm identities are used to systematically construct dimensionally homogeneous groups of objective functions. The concept of an ideal minimizing matrix is introduced for both hexahedral and tetrahedral elements. Non-dimensional objective functions having barriers are emphasized as the most logical choice for mesh optimization. The performance of a number of objective functions in improving mesh quality was assessed on a suite of realistic test problems, focusing particularly on all-hexahedral ''whisker-weaved'' meshes. Performance is investigated on both structured and unstructured meshes and on both hexahedral and tetrahedral meshes. Although several objective functions are competitive, the condition number objective function is particularly attractive. The objective functions are closely related to mesh quality measures. To illustrate, it is shown that the condition number metric can be viewed as a new tetrahedral element quality measure.

Knupp, P.M.

1999-03-26

228

Optimization of Ni–Cr flux growth for hexagonal boron nitride single crystals  

NASA Astrophysics Data System (ADS)

Hexagonal boron nitride (hBN) single crystals were grown using a Ni–Cr flux growth method. The crystallization cooling rate, soak temperature and soak time were controlled to determine their effect on crystal size and quality. A cooling rate of 2 °C/h produced the best quality hBN crystals. The maximum crystal width increased with soak temperature from 1 mm at 1450 °C to 5 mm at 1700 °C. The crystal thickness decreased with soak temperature from 500 µm at 1500 °C to 40 µm at 1700 °C. A soak time of 24 to 48 h produced the maximum crystal thickness. X-ray diffraction and Raman spectroscopy confirmed that the crystals were highly ordered and of high purity.

Hoffman, T. B.; Clubine, B.; Zhang, Y.; Snow, K.; Edgar, J. H.

2014-05-01

229

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

230

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

231

The Relationship of Leadership Styles, Gender and Years of Experience of Middle School Principals in North Carolina on Achievement and Growth Trends on the End of Grade Exams  

ERIC Educational Resources Information Center

Leadership is an ever changing process and principals play a key role in the instructional focus of a school which often times created success in instruction (Riordan, 2003). Principals face different challenges today while improving schools and student academic achievement. The perceptions of an effective school leader has changed over the years…

Brooks, Morris, Jr.

2009-01-01

232

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

ERIC Educational Resources Information Center

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

Benson, James G.; Borman, Geoffrey D.

2007-01-01

233

Effect of a Career, Academic, Personal and Social Growth High School Transition Program Option on 9th-Grade Students' Achievement, Behavior, and Engagement  

ERIC Educational Resources Information Center

The purpose of this study was to determine the effect of a career, academic, personal, and social high school transition program option on 9th-grade students' achievement, behavior, and engagement. Students in the career, academic, personal, and social group (n = 30) and the comparison academic/elective course option programs group (n = 30)…

Gauchat, Tiffanie A.

2010-01-01

234

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.

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

2014-01-01

235

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

236

Two internal type II NADH dehydrogenases of Toxoplasma gondii are both required for optimal tachyzoite growth.  

PubMed

In many apicomplexan parasites the entry of electrons from NADH into the electron transport chain is governed by type II NADH dehydrogenases (NDH2s) instead of a canonical complex I. Toxoplasma gondii expresses two NDH2 isoforms, TgNDH2-I and TgNDH2-II with no indication for stage-specific regulation. We dissected the orientation of both isoforms by using a split GFP assay and a protease protection assay after selective membrane permeabilization. The two approaches revealed that both TgNDH2 isoforms are internal enzymes facing with their active sites to the mitochondrial matrix. Single knockout mutants displayed a decreased replication rate and a reduced mitochondrial membrane potential, which were both more severe in the Tgndh2-II-deleted than in the Tgndh2-I-deleted mutant. Complementation with a myc-tagged, ectopic copy of the deleted gene restored the growth rate and the mitochondrial membrane potential. However, an overexpression of the remaining intact isoform could not restore the phenotype, suggesting that the two TgNDH2 isoforms are non-redundant and possess functional differences. Together, our studies indicate that although TgNDH2-I and TgNDH2-II are individually non-essential, the expression of both internal isoforms is required to maintain the mitochondrial physiology in T. gondii tachyzoites. PMID:21854467

Lin, San San; Gross, Uwe; Bohne, Wolfgang

2011-10-01

237

An effective approach to achieving low supersaturation for a/b-axis oriented YBa2Cu3O7-? film growth.  

PubMed

Using liquid phase epitaxy, a novel approach was developed to grow a-axis oriented YBa2Cu3O7-? films (a-films) under an air atmosphere, which has been difficult previously since its formation requires extremely low supersaturation. In our new method, instead of conventional cooling from the saturated to supersaturated state, an extremely small driving force for film growth was generated from the unsaturated through saturated to supersaturated state. By controlling the amount of fresh solvent and the melting time before cooling down the Y-Ba-Cu-O solution, a growth region width up to 30 K was acquired for preparing a-films. Significantly, this work provides a low-cost and convenient way to produce high-quality a-films, which are potentially suitable for Josephson junction devices. PMID:24968344

Guo, L S; Chen, Y Y; Yao, X

2014-07-15

238

Epstein-Barr Virus Exploits BSAP\\/Pax5 To Achieve the B-Cell Specificity of Its Growth-Transforming Program  

Microsoft Academic Search

Epstein-Barr virus (EBV) can infect various cell types but limits its classical growth-transforming function to B lymphocytes, the cells in which it persists in vivo. Transformation initiates with the activation of Wp, a promoter present as tandemly repeated copies in the viral genome. Assays with short Wp reporter constructs have identified two promoter-activating regions, one of which (UAS2) appears to

Rosemary Tierney; Jasdeep Nagra; Isabel Hutchings; Claire Shannon-Lowe; Markus Altmann; Wolfgang Hammerschmidt; Alan Rickinson; Andrew Bell

2007-01-01

239

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

PubMed Central

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

Merchant, Sabeeha S.; Helmann, John D.

2014-01-01

240

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

PubMed

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

Merchant, Sabeeha S; Helmann, John D

2012-01-01

241

Achieving Optimal Enrollments and Tuition Revenues.  

ERIC Educational Resources Information Center

A modern marketing approach to student recruitment is offered as a means of facilitating institutional planning, enhancing communication with prospective students, improving enrollment forecasting, and eliminating unexpected shortfalls in tuition income. Marketing is distinguished from mere salesmanship and discussed in a practical program of…

Ihlanfeldt, William

242

Optimizing the growth of 1.3 ?m InAs/InGaAs dots-in-a-well structure  

NASA Astrophysics Data System (ADS)

The structural and optical properties of GaAs-based 1.3 ?m InAs/InGaAs dots-in-a-well (DWELL) structures have been optimized in terms of different InGaAs and GaAs growth rates, the amount of InAs deposited, and In composition of the InGaAs quantum well (QW). An improvement in the optical efficiency is obtained by increasing the growth rate of the InGaAs and GaAs layers. A transition from small quantum dots (QDs), with a high density (~5.3×1010 cm-2) and broad size distribution, to larger quantum dots with a low dot density (~3.6×1010 cm-2) and narrow size distribution, occurs as the InAs coverage is increased from 2.6 to 2.9 monolayers. The room-temperature optical properties also improve with increased InAs coverage. A strong dependence of the QD density and the QD emission wavelength on the In composition of InGaAs well has been observed. By investigating the dependence of the dot density and the high-to-width ratio of InAs islands on the matrix of InGaAs strained buffer layer (SBL), we show that the increasing additional material from wetting layer and InGaAs layer into dots and the decreasing repulsive strain field between neighboring islands within substrate are responsible for improving QD density with increasing In composition in InGaAs SBL. The optical efficiency is sharply degraded when the InGaAs QW In composition is increased from 0.15 to 0.2. These results suggest that the optimum QW composition for 1.3 ?m applications is ~15%. Our optimum structure exhibits a room temperature emission of 1.32 ?m with a linewidth of 27 meV.

Liu, H. Y.; Hopkinson, M.; Harrison, C. N.; Steer, M. J.; Frith, R.; Sellers, I. R.; Mowbray, D. J.; Skolnick, M. S.

2003-03-01

243

Evaluation of a novel collagen-gelatin scaffold for achieving the sustained release of basic fibroblast growth factor in a diabetic mouse model.  

PubMed

The objective of this study was to evaluate the ability of a scaffold, collagen-gelatin sponge (CGS), to release basic fibroblast growth factor (bFGF) in a sustained manner, using a pressure-induced decubitus ulcer model involving genetically diabetic mice. We confirmed that CGSs impregnated with a bFGF concentration of up to 50 µg/cm(2) were able to sustain the release of bFGF throughout their biodegradation. We prepared decubitus ulcers on diabetic mice. After debriding the ulcers, we implanted CGSs (diameter 8 mm) impregnated with normal saline solution (NSS) or bFGF solution (7, 14, 28 or 50 µg/cm(2)). At 1 and 2 weeks after implantation, the mice were sacrificed and tissue specimens were obtained. The wound area, neoepithelium length and numbers and total area of newly formed capillaries were evaluated. The CGSs impregnated with NSS became infected and degraded, whereas the CGSs impregnated with 7 or 14 µg/cm(2) bFGF displayed accelerated dermis-like tissue formation and the CGSs impregnated with 14 µg/cm(2) bFGF produced significant improvements in the remaining wound area, neoepithelium length and numbers and total area of newly formed capillaries compared with the NSS group. No significant difference was observed between the NSS and 50 µg/cm(2) bFGF groups. CGSs impregnated with 7-14 µg/cm(2) bFGF accelerated wound healing, and an excess amount of bFGF did not increase the wound-healing efficacy of the CGSs. Our CGS is a scaffold that can release positively charged growth factors such as bFGF in a sustained manner and shows promise as a scaffold for skin regeneration. PMID:22628359

Kanda, Norikazu; Morimoto, Naoki; Ayvazyan, Artem A; Takemoto, Satoru; Kawai, Katsuya; Nakamura, Yoko; Sakamoto, Yuki; Taira, Tsuguyoshi; Suzuki, Shigehiko

2014-01-01

244

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.

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

2014-01-01

245

Developmental physiology of cestodes. XIV. Roughage and carbohydrate content of host diet for optimal growth and development of Hymenolepis diminuta.  

PubMed

Diets of rats infected with Hymenolepis diminuta (CESTODA: Cyclophyllidea) were altered with respect to carbohydrate content and to roughage, and the effects on worm growth and development were studied. Compared to worms from rats fed a 56% glucose diet, those on a 56% starch diet were heavier at 10 and 15 days and had more immature proglottids at 5 days, mature prglottids at 10 days, and mature and gravid proglottids at 15 days postinfection. In addition, worms from rats fed the starch diet contained a higher carbohydrate concentration and a lower lipid concentration from those fed the glucose diet. Worms from rats fed diets with combinations of carbohydrates such as 51% starch-5% sucrose and 51% starch-5% lactose were not different from those fed the 56% starch diet. If rats were fed a pellet diet (Purina Laboratory Chow), the worms grew substantially larger than those from rats fed the 56% starch or combination diets. The differences could be overcome if a 6% roughage component were included in the 56% starch diet. Therefore, the starch-roughage diet here presented is recommended as the optimal defined diet for studies of the development of H. diminuta in the definitive host. PMID:1138038

Komuniedki, R; Roberts, L S

1975-06-01

246

Optimization of codon composition and regulatory elements for expression of human insulin like growth factor-1 in transgenic chloroplasts and evaluation of structural identity and function  

Microsoft Academic Search

BACKGROUND: Transgenic chloroplasts are potential bioreactors for recombinant protein production, especially for achievement of high levels of protein expression and proper folding. Production of therapeutic proteins in leaves provides transgene containment by elimination of reproductive structures. Therefore, in this study, human Insulin like Growth Factor-1 is expressed in transgenic chloroplasts for evaluation of structural identity and function. RESULTS: Expression of

Henry Daniell; Gricel Ruiz; Bela Denes; Laurence Sandberg; William Langridge

2009-01-01

247

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

248

Optimization of GaN Growth with Ga-Polarity by Referring to Surface Reconstruction Reflection High-Energy Electron Diffraction Patterns  

NASA Astrophysics Data System (ADS)

GaN films with Ga-polarity on (0001) sapphire substrates grown by plasma-assisted molecular beam epitaxy were investigated. The optimization of the growth conditions was performed referring to reflection high-energy electron diffraction reconstruction patterns during the cooling processes. Three kinds of surface reconstruction patterns, named (5× 5), (1× 2) and (2× 2), were observed during the cooling processes. Structural, optical and electrical properties of the GaN films, identified by different reconstruction patterns, were characterized to determine the optimal growth conditions. It was found that high-quality films can be obtained when the films show the (1× 2) pattern. Under this condition, we obtained an electron mobility at room temperature of as high as 567 cm2/Vs without using a GaN template.

Shen, Xu-Qiang; Ide, Toshihide; Cho, Sung-Hwan; Shimizu, Mitsuaki; Hara, Shiro; Okumura, Hajime; Sonoda, Saki; Shimizu, Saburo

2001-01-01

249

Characterization and Optimization of Atomic Hydrogen Cleaning of InP Surface for Selective Molecular Beam Epitaxial Growth of InGaAs Quantum Structure Arrays  

Microsoft Academic Search

An oxide removal process for InP surface using atomic hydrogen cleaning was characterized and optimized for use in the selective molecular beam epitaxial (MBE) growth of InGaAs quantum structures. In-situ X-ray photoelectron spectroscopy (XPS), reflection high energy electron diffraction (RHEED), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques were used. Detailed XPS measurements clarified the effects of atomic

Tsutomu Muranaka; Chao Jiang; Akira Ito; Hideki Hasegawa

2001-01-01

250

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

251

Achieving high Curie temperature in (Ga,Mn)As  

SciTech Connect

We study the effects of growth temperature, Ga:As ratio, and postgrowth annealing procedure on the Curie temperature T{sub C} of (Ga,Mn)As layers grown by molecular beam epitaxy. We achieve the highest T{sub C} values for growth temperatures very close to the two-dimensional-three-dimensional phase boundary. The increase in T{sub C}, due to the removal of interstitial Mn by postgrowth annealing, is counteracted by a second process, which reduces T{sub C} and which is more effective at higher annealing temperatures. Our results show that it is necessary to optimize the growth parameters and postgrowth annealing procedure to obtain the highest T{sub C}.

Wang, M.; Campion, R. P.; Rushforth, A. W.; Edmonds, K. W.; Foxon, C. T.; Gallagher, B. L. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2008-09-29

252

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

Microsoft Academic Search

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

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

2011-01-01

253

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.

Gupta, Vishal; Lee, Marilyn

2012-01-01

254

Growth of wildtype and mutant E. coli strains in minimal media for optimal production of nucleic acids for preparing labeled nucleotides  

PubMed Central

Since RNAs lie at the center of most cellular processes, there is a need for synthesizing large amounts of RNAs made from stable isotope-labeled nucleotides to advance the study of their structure and dynamics by nuclear magnetic resonance (NMR) spectroscopy. A particularly effective means of obtaining labeled nucleotides is to harvest these nucleotides from bacteria grown in defined minimal media supplemented with 15NH4Cl and various carbon sources. Given the high cost of carbon precursors required for labeling nucleic acids for NMR studies, it becomes important to evaluate the optimal growth for commonly used strains under standard minimal media conditions. Such information is lacking. In this study, we characterize the growth for Escherichia coli strains K12, K10zwf, and DL323 in three minimal media with isotopic-labeled carbon sources of acetate, glycerol, and glycerol combined with formate. Of the three media, the LeMaster-Richards and the Studier media outperform the commonly used M9 media and both support optimal growth of E. coli for the production of nucleotides. However, the growth of all three E. coli strains in acetate is reduced almost twofold compared to growth in glycerol. Analysis of the metabolic pathway and previous gene array studies help to explain this differential growth in glycerol and acetate. These studies should benefit efforts to make selective 13C-15N isotopic-labeled nucleotides for synthesizing biologically important RNAs. Electronic supplementary material The online version of this article (doi:10.1007/s00253-010-2813-y) contains supplementary material, which is available to authorized users.

Thakur, Chandar S.; Brown, Margaret E.; Sama, Jacob N.; Jackson, Melantha E.

2010-01-01

255

Optimization of the medium composition of a biphasic production system for mycelial growth and spore production of Aschersonia placenta using response surface methodology.  

PubMed

The culture media for mycelial growth and sporulation of the entomopathogenic fungus Aschersonia placenta were optimized using the response surface method (RSM). Interactions of medium components and the optimization of a biphasic production system were studied using Box-Behnken design (BBD) with three levels of three variables. Experimentation confirmed that the model developed based on RSM and BBD successfully predicted mycelia production (R(2) = 0.9336) and conidia production (R(2) = 0.9532). In the first phase, mycelial dry weight was highest (2.14 ± 0.17 g per 100ml of culture, mean±SE) when the concentrations (g/l) of glucose, vitamin B(6), and MgSO(4)·7H(2)O were 31.4, 11.5, and 0.64, respectively. In the second phase, conidia production was highest (9.31 ± 0.48 × 10(7)sporespercm(2)) after 18d of cultivation in the medium containing 33.8 g/l of millet, 1.11 g/l of KH(2)PO(4), and 0.37 g/l of MgSO(4). Mycelial and conidial yields were 3.6- and 10-fold greater, respectively, with the optimized media than with the non-optimized basal media. The results indicate that RSM and BBD methods are effective for increasing the production of A. placenta mycelia and conidia. PMID:23174147

Qiu, Junzhi; Song, Feifei; Qiu, Yunfeng; Li, Xiaoxia; Guan, Xiong

2013-02-01

256

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

257

Suppressing void defects in long wavelength semipolar (2021) InGaN quantum wells by growth rate optimization  

NASA Astrophysics Data System (ADS)

We report on void defect formation in (2021) semipolar InGaN quantum wells (QWs) emitting in the green spectral region. Fluorescence and transmission electron microscopy studies indicate that this type of defect is associated with voids with {1011}, {1010}, and {0001} side facets in the QW region. Systematic growth studies show that this defect can be effectively suppressed by reducing the growth rate for the active region. Green light-emitting diodes (LEDs) with reduced active region growth rate showed enhanced power and wavelength performance. The improved LED performance is attributed to the absence of void defects in the active region.

Zhao, Yuji; Wu, Feng; Huang, Chia-Yen; Kawaguchi, Yoshinobu; Tanaka, Shinichi; Fujito, Kenji; Speck, James S.; DenBaars, Steven P.; Nakamura, Shuji

2013-03-01

258

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

NASA Astrophysics Data System (ADS)

We present results on optimized growth temperatures and layer structure design of high mobility photoconductive Terahertz (THz) emitters based on molecular beam epitaxy grown In0.53Ga0.47As/In0.52Al0.48As 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 × 10-3.

Dietz, Roman J. B.; Globisch, Björn; Gerhard, Marina; Velauthapillai, Ajanthkrishna; Stanze, Dennis; Roehle, Helmut; Koch, Martin; Göbel, Thorsten; Schell, Martin

2013-08-01

259

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

260

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

261

On the design of optimal dynamic experiments for parameter estimation of a Ratkowsky-type growth kinetics at suboptimal temperatures  

Microsoft Academic Search

It is generally known that accurate model building, i.e., proper model structure selection and reliable parameter estimation, constitutes an essential matter in the field of predictive microbiology, in particular, when integrating these predictive models in food safety systems. In this context, Versyck et al. (1999) have introduced the methodology of optimal experimental design techniques for parameter estimation within the field.

Kristel Bernaerts; Karina J. Versyck; Jan F. Van Impe

2000-01-01

262

Statistical optimization of medium components and growth conditions by response surface methodology to enhance phenol degradation by Pseudomonas putida  

Microsoft Academic Search

In this work, a four-level Box–Behnken factorial design was employed combining with response surface methodology (RSM) to optimize the medium composition for the degradation of phenol by pseudomonas putida (ATCC 31800). A mathematical model was then developed to show the effect of each medium composition and their interactions on the biodegradation of phenol. Response surface method was using four levels

Gurusamy Annadurai; Lai Yi Ling; Jiunn-Fwu Lee

2008-01-01

263

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

264

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

PubMed Central

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

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

2013-01-01

265

Women, Motivation, and Achievement.  

ERIC Educational Resources Information Center

Reviews psychological research on motivation and educational achievement, discussing gender and contributions by feminist researchers. Feminist psychologists note sex bias and methodological flaws in traditional research on achievement motivation, proposing improved models (Eccles' expectancy x value model of achievement behavior). Contrary to…

Hyde, Janet Shibley; Kling, Kristen C.

2001-01-01

266

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

Microsoft Academic Search

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

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

2011-01-01

267

Lowering Bone Mineral Affinity of Bisphosphonates as a Therapeutic Strategy to Optimize Skeletal Tumor Growth Inhibition In vivo  

Microsoft Academic Search

Bisphosphonates bind avidly to bone mineral and are potent inhibitors of osteoclast-mediated bone destruction. They also exhibit antitumor activity in vitro. Here, we used a mouse model of human breast cancer bone metastasis to examine the effects of risedronate and NE-10790, a phosphonocarboxylate analogue of the bisphosphonate risedronate, on osteolysis and tumor growth. Osteolysis was measured by radiography and histomorphometry.

Pierrick G. J. Fournier; Florence Daubine; Mark W. Lundy; Michael J. Rogers; Frank H. Ebetino; Philippe Clezardin

2008-01-01

268

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

269

Optimality Conditions for Cell-Fate Heterogeneity That Maximize the Effects of Growth Factors in PC12 Cells  

PubMed Central

Recently, the heterogeneity that arises from stochastic fate decisions has been reported for several types of cancer-derived cell lines and several types of clonal cells grown under constant environmental conditions. However, the relation between this stochasticity and the responsiveness to extracellular stimuli remains largely unknown. Here we focused on the fate decisions of the PC12 cell line, which was derived from rat pheochromocytoma, and is a model system to study differentiation into sympathetic neurons. Whereas epidermal growth factor (EGF) stimulates the proliferation of populations of PC12 cells, nerve growth factor (NGF) promotes the differentiation of neurites to neuron-like cells. We found that phenotypic heterogeneity increased with time at several surrounding serum concentrations, suggesting stochastic cell-fate decisions in single cells. We made a simple mathematical model assuming Markovian transitions of the cell fates, and estimated the transition rates based on Bayes' theorem. The model suggests that depending on the serum concentration, EGF (NGF) even directs differentiation (proliferation) at the single-cell level. The maximum effects of the growth factors were ensured when the transition rates were appropriately controlled by the serum concentration to produce a nonextremal, moderate amount of cell-fate heterogeneity. Our model was validated by the experimental finding that the means and variances of the local cell densities obey a power-law relationship. These results suggest that even when efficient responses to growth factors are observed at the population level, the growth factors stochastically direct the cell-fate decisions in different directions at the single-cell level.

Mouri, Kazunari; Sako, Yasushi

2013-01-01

270

Enhanced Growth of Influenza Vaccine Seed Viruses in Vero Cells Mediated by Broadening the Optimal pH Range for Virus Membrane Fusion  

PubMed Central

Vaccination is one of the most effective preventive measures to combat influenza. Prospectively, cell culture-based influenza vaccines play an important role for robust vaccine production in both normal settings and urgent situations, such as during the 2009 pandemic. African green monkey Vero cells are recommended by the World Health Organization as a safe substrate for influenza vaccine production for human use. However, the growth of influenza vaccine seed viruses is occasionally suboptimal in Vero cells, which places limitations on their usefulness for enhanced vaccine production. Here, we present a strategy for the development of vaccine seed viruses with enhanced growth in Vero cells by changing an amino acid residue in the stem region of the HA2 subunit of the hemagglutinin (HA) molecule. This mutation optimized the pH for HA-mediated membrane fusion in Vero cells and enhanced virus growth 100 to 1,000 times in the cell line, providing a promising strategy for cell culture-based influenza vaccines.

Murakami, Shin; Ito, Mutsumi; Takano, Ryo; Katsura, Hiroaki; Shimojima, Masayuki

2012-01-01

271

Response surface methodology for optimization of growth parameters for the production of carotenoids by a mutant strain of Rhodotorula gracilis  

Microsoft Academic Search

Response surface methodological studies of growth parameters for carotenoid production by a mutant strain of Rhodotorula gracilis (CFR 0-1) was carried out by a two-level fractional factorial design involving five variables, namely glucose concentration (%), incubation period (days), volume of inoculum (ml\\/100 ml), pH, and temperature (°C). The response equation developed indicated linear relationship between period of incubation, temperature, sugar

Govindaswamy Vijayalakshmi; Basavanna Shobha; Vasudeva Vanajakshi; Soundar Divakar; Balaraman Manohar

2001-01-01

272

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

273

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

Microsoft Academic Search

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

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

2009-01-01

274

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

PubMed Central

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.

Lee, Unn-Hwa; Cho, Wha Ja; Cha, Seung Ju; Do, Jeong Wan; Heo, Gang Joon; Jeong, Soo Geun; Hahm, Yoo Sik; Harmache, Abdallah; Bremont, Michel; Kurath, Gael; Park, Jeong Woo

2011-01-01

275

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

276

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

277

Growth optimization of InGaP layers by solid source molecular beam epitaxy for the application of InGaP/In 0.2Ga 0.8As/GaAs high electron mobility transistor structures  

NASA Astrophysics Data System (ADS)

InGaP/GaAs layers were grown by solid source molecular beam epitaxy using a valved phosphorus cracker cell. The photoluminescence (PL) peak energy of the InGaP epilayers increased with the increase of the V/III flux ratio and decrease of the substrate temperature. High-quality InGaP epilayers with a PL FWHM of 6.5 meV were obtained by using the optimized growth conditions. The InGaP layers were incorporated in the InGaP/In 0.20Ga 0.80As/GaAs pseudomorphic high electron mobility transistor structures. This structure showed low two-dimensional electron gas mobility, which was found to be attributed to the InGaP/InGaAs interface. Despite the low mobility for the InGaP/In 0.20Ga 0.80As/GaAs HEMT structures, very promising device results have been achieved.

Zheng, H. Q.; Yoon, S. F.; Gay, B. P.; Mah, K. W.; Radhakrishnan, K.; Ng, G. I.

2000-06-01

278

Growth of Optimized Gallium-Arsenide Gallium)arsenic Modulation Doped Heterostructures by Molecular Beam Epitaxy for Fet Applications.  

NASA Astrophysics Data System (ADS)

Modulation-doped field-effect transistors (MODFET's) have received a great deal of attention recently due to their potential in microwave analog and high-speed digital applications. In this thesis, three different GaAs/(Al,Ga)As modulation doped heterostructures: (1) planar doped heterostructures; (2) heterostructure with AlAs spacer and (3) heterostructure using atomic plane doping, which offer various advantages over the conventional one, are studied. A heterostructure employing thin ((TURN)100(ANGSTROM)), doped AlGaAs capped with undoped and graded AlGaAs, which has shown improved high temperature annealing performance, has been developed particularly for ion-implanted self-aligned MODFET technology. Transconductances of 204 mS/mm at room temperature and 310 mS/mm at 77K have been achieved. Modulation doped GaAs/(Al,Ga)As heterostructures using AlAs spacer layer and atomic plane Si doping technique have been grown by MBE. Electron mobilities of 7,100 cm('2)/V -sec at 300K and 135,000 cm('2)/V-sec at 77K have also been obtained on heterostructures with an AlAs spacer layer, indicating good interface between GaAs and AlAs. The higher conduction band discontinuity at the heterojunction interface provided by the larger bandgap of AlAs compared to Al(,x)Ga(,1 -x)As (x (TURN) 0.3) normally used offers the following advantages: (1) better annealing characteristics, i.e., maintaining high 2DEG mobility and stable ns after high temperature annealing up to 900(DEGREES)C, which is crucial for the fabrication of ion-implanted self-aligned MODFETs; (2) raised first excited subband level, hence high electron mobility can be achieved even at high ns. As for the atomic plane Si doping, a thin ((TURN) 0.1% monolayer) Si was used to dope the heterostructures. Electron mobilities of 7160 cm('2)/V-sec at 300K and 122,500 cm('2)/V-sec at 77K with n(,s) of 4.2 x 10('11) cm('-2) have been achieved. This technique has the potential use on MODFETs to reduce the thickness between gate and 2DEG channel, thereby enhance the transconductance which is important for microwave and high speed logic applications. In addition to the new structures, extrinsic transconductances of 450 mS/mm at 300K and 580 mS/mm at 77K have also been achieved for the 0.33 (mu)m gate length MODFET using conventional structure.

Lee, Hao

279

Experimental study of the kinetically-limited decomposition of ZnGeAs 2 and its role in determining optimal conditions for thin film growth  

NASA Astrophysics Data System (ADS)

To understand the thermochemistry and determine the rate limiting steps of ZnGeAs 2 thin-film synthesis, experiments were performed to measure the (a) thermal decomposition rate and (b) elemental composition and deposition rate of films produced with pulsed laser deposition (PLD). The decomposition rate is kinetically limited with an activation energy of 1.08±0.05 eV and an evaporation coefficient of ˜10 -3. We show that ZnGeAs 2 thin film synthesis is a metastable process with the kinetically-limited decomposition rate playing a dominant role at the elevated temperatures needed to attain epitaxy. Our conclusions are in contrast to those of earlier reports that assumed the growth rate is limited by desorption and the resulting low reactant sticking coefficient. The thermochemical analysis presented here can be used to predict optimal conditions for ZnGeAs 2 film physical vapor deposition and thermal processing.

Vahidi, M.; Tang, Z. Z.; Tucker, J.; Peshek, T. J.; Zhang, L.; Kopas, C.; Singh, R. K.; van Schilfgaarde, M.; Newman, N.

2012-01-01

280

Achievement Test Program.  

ERIC Educational Resources Information Center

The Ohio Trade and Industrial Education Achievement Test battery is comprised of seven basic achievement tests: Machine Trades, Automotive Mechanics, Basic Electricity, Basic Electronics, Mechanical Drafting, Printing, and Sheet Metal. The tests were developed by subject matter committees and specialists in testing and research. The Ohio Trade and…

Ohio State Dept. of Education, Columbus. Trade and Industrial Education Service.

281

Tackling low educational achievement  

Microsoft Academic Search

This report examines the factors underlying low achievement in British education. It is important to find out why tens of thousands of young people leave school with no or very few qualifications. Low achievement at age 16 is associated with disadvantage and also a variety of outcomes by gender and ethnic group. Existing policies and practices within the educational system

Robert Cassen; Geeta Kingdon

2007-01-01

282

Inverting the Achievement Pyramid  

ERIC Educational Resources Information Center

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

White-Hood, Marian; Shindel, Melissa

2006-01-01

283

Nutrition and school achievement  

Microsoft Academic Search

Investments in education have traditionally ignored the productive role of nutrition. This study of the relationships between nutritional status and learning among urban and rural Filipino children shows the possible complementarity of nutrition with other social investments aimed at improving school achievement. A traditional production function of learning approach is used to show the significant association between school achievement and

Barry M. Popkin; Marisol Lim-Ybanez

1982-01-01

284

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

285

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

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

Achievement-Based Resourcing.  

ERIC Educational Resources Information Center

This collection of seven articles examines achievement-based resourcing (ABR), the concept that the funding of educational institutions should be linked to their success in promoting student achievement, with a focus on the application of ABR to postsecondary education in the United Kingdom. The articles include: (1) "Introduction" (Mick…

Fletcher, Mike; And Others

1992-01-01

288

General Achievement Trends: Nevada  

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

Aiming at Achievement.  

ERIC Educational Resources Information Center

The Raising Quality and Achievement Program is a 3-year initiative to support further education (FE) colleges in the United Kingdom in their drive to improve students' achievement and the quality of provision. The program offers the following: (1) quality information and advice; (2) onsite support for individual colleges; (3) help with…

Martinez, Paul

290

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

PubMed Central

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

Letort, Veronique; Mahe, Paul; Cournede, Paul-Henry; de Reffye, Philippe; Courtois, Brigitte

2008-01-01

291

Construction of high-resolution trace element time-series in slow growth speleothems by LA-ICP-MS: Importance of parameter optimization and oriented band fabric imagery  

NASA Astrophysics Data System (ADS)

Establishing high-resolution trace element time series in speleothems requires analytical techniques capable of representative sampling at sub-annual spatial resolution, but also possessing sufficient signal-to-noise to reliably discern potential season-to-season concentration variations. Growth rate is a major factor affecting both of these analytical challenges. To date, LA-ICP-MS, LA-MC-ICP-MS, SIMS, and ?XRF techniques have been successfully applied to speleothem records, but nearly all studies have focused on speleothems with relatively fast growth rates of ? 100 ?m/yr and which display well-defined banding. U-series dating of central Texas speleothems of the Edwards aquifer karst system demonstrate that calcite growth followed glacial-interglacial climate transitions spanning the past 70 ky. In contrast to previous high-resolution studies, central Texas speleothem growth rates seldom exceeded 25-50?m/yr and thus reside within a "slow-growth" (< 100 ?m/yr) regime. Furthermore, seasonal banding is seldom revealed by conventional petrographic methods, thus complicating temporal/spatial sampling. To meet the analytical challenges posed by slow growth speleothems, we present an approach using LA-ICP-MS that integrates ablation and ionization parameters customized for speleothem calcite with oriented UV-fluorescence imagery. Ablation aerosol generation, transport, and ionization efficiency in the ICP are major interrelated factors affecting resolution of micro-scale, chemically-banded materials. To enhance chemical variations in finely banded materials, the aperture diameter must: (1) not exceed the critical sampling limit defined by the Nyquist frequency of the effective chemical waveform, whether sinusoidal or otherwise skewed with a higher frequency limb; and (2) must be capable of generating signals in excess of natural lateral heterogeneity and analytical noise components of measurement. Fabric-oriented, slow line scans, using narrow (5?m) rectangular slit apertures, offer substantially improved spatial resolution over spot apertures. The addition of nitrogen (5 mL/min) to the carrier gas following the ablation cell generates a three- to five-fold increase in sensitivity for Mg, Sr and Ba. The technique involves establishing a grid of laser spots over prospective sample areas in order to provide precise correlation points for overlaying of UV-fluorescence imagery. The georeferenced imagery, which reveals the banded growth fabric, is then used to orient line scans so that the long-axis of the slit aperture is held parallel to banding throughout the length of the scan. For optimization of ablation and ionization parameters, the grid is rotated 90° so that line scans are performed parallel to banding (for which natural lateral heterogeneity can also be evaluated). Through the application of these techniques we are able to construct trace element signals that closely mimic the UV-fluorescence band spacing and are consistent with U-series growth-rate predictions, suggesting the possibility of subannual resolution at growth rates as slow as 23 ?m/yr.

Miller, N. R.; Griffiths, R. E.; Banner, J. L.

2012-12-01

292

Epidermal growth factor can optimize a serum-free culture system for bone marrow stem cell proliferation in a miniature pig model.  

PubMed

Bone marrow-derived mesenchymal stem cells have become an attractive cell source for periodontal ligament regeneration treatment because of their potential to engraft to several tissue types after injury. Most researchers have focused on the transplantation process, but few have paid attention to cell safety concerns and rapid proliferation before transplantation. Using serum-free medium to culture stem cells may be an effective method to avoid problems associated with exogenous serum and the addition of growth factors to promote cell proliferation. Here, we randomly divided our serum-free cultures and treated them with different levels of epidermal growth factor (EGF). We then evaluated changes in rates of cell adhesion, proliferation, apoptosis, and cell cycle ratio as well as their differentiation potential. The data showed that all of these parameters were significantly different when comparing serum-free cultures with and without 10 nM/L EGF (p < 0.05/0.01); however, cells with 10 nM/L EGF did not respond differently than cells grown in standard serum-containing media without EGF (p > 0.05). In summary, our results demonstrate that 10 nM/L EGF was the optimal dose for serum-free culture, which can replace traditional standard serum medium for in vitro expansion of miniature pig bone marrow-derived mesenchymal stem cells. PMID:24002665

Wang, Xuan; Zheng, Feng; Liu, Ousheng; Zheng, Shutao; Liu, Yishan; Wang, Yuehong; Tang, Zhangui; Zhong, Liangjun

2013-12-01

293

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

294

Use of a D-optimal mixture design to estimate the effects of diverse chloride salts on the growth parameters of Lactobacillus pentosus.  

PubMed

The effects of NaCl, KCl, CaCl(2), and MgCl(2) and their mixtures on the ionic strength (IS) of the medium and the growth parameters of Lactobacillus pentosus were studied by means of a D-optimal mixture experimental design with constrains (total salt concentrationCaCl(2)>NaCl>KCl. Within the experimental region, the lag phase duration (lambda) was mainly affected by NaCl and CaCl(2) and the interaction KCl with MgCl(2). The maximum specific growth rate (mu(max)) decreased as NaCl (the highest effect), CaCl(2), and MgCl(2) increased (regardless of the presence or not of previous NaCl); low KCl concentrations had a stimulating effect on mu(max), but its overall effect showed a similar trend to the other salts. The maximum population reached (N(max)) was the least affected parameter and decreased as NaCl and CaCl(2) concentrations increased regardless of the presence of the other salts. The equations that expressed the growth parameters as a function of the diverse chloride salts, within the limits assayed, were developed and the corresponding z- and harmonic Z-values were estimated. PMID:19376461

Arroyo-López, F N; Bautista-Gallego, J; Chiesa, A; Durán-Quintana, M C; Garrido-Fernández, A

2009-06-01

295

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

296

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

297

The accumulation of glutamate is necessary for optimal growth of Salmonella typhimurium in media of high osmolality but not induction of the proU operon.  

PubMed Central

Synthesis of glutamate can be limited in bacterial strains carrying mutations to loss of function of glutamate synthase (2-oxoglutarate:glutamine aminotransferase) by using low concentrations of NH4+ in the growth medium. By using such gltB/D mutant strains of Salmonella typhimurium, we demonstrated that: (i) a large glutamate pool, previously observed to correlate with growth at high external osmolality, is actually required for optimal growth under these conditions; (ii) the osmoprotectant glycine betaine (N,N,N-trimethylglycine) apparently cannot substitute for glutamate; and (iii) accumulation of glutamate is not necessary for high levels of induction of the proU operon in vivo. Expression of the proU operon, which encodes a transport system for the osmoprotectants proline and glycine betaine, is induced > 100-fold in the wild-type strain under conditions of high external osmolality. Ramirez et al. (R. M. Ramirez, W. S. Prince, E. Bremer, and M. Villarejo, Proc. Natl. Acad. Sci. USA 86:1153-1157, 1989) observed and we confirmed that in vitro expression of the lacZ gene from the wild-type proU promoter is stimulated by 0.2 to 0.3 M K glutamate. However, we observed a very similar stimulation for lacZ expressed from the lacUV5 promoter and from the proU promoter when an important negative regulatory element downstream of this promoter (the silencer) was deleted. Since the lacUV5 promoter is not osmotically regulated in vivo and osmotic regulation of the proU promoter is largely lost as a result of deletion of the silencer, we conclude that stimulation of proU expression by K glutamate in vitro is not a specific osmoregulatory response but probably a manifestation of the optimization of in vitro transcription-translation at high concentrations of this solute. Our in vitro and in vivo results demonstrate that glutamate is not an obligatory component of the transcriptional regulation of the proU operon.

Csonka, L N; Ikeda, T P; Fletcher, S A; Kustu, S

1994-01-01

298

Attractiveness and School Achievement  

ERIC Educational Resources Information Center

The purpose of this study was to ascertain the relationship between rated attractiveness and two measures of school performance. Attractive children received significantly higher report cards and, to some degree, higher achievement test scores than their unattractive peers. (Author)

Salvia, John; And Others

1977-01-01

299

Optimization of chemical vapor deposition diamond films growth on steel: correlation between mechanical properties, structure, and composition.  

PubMed

In the present work we perform optimization of mechanical and crystalline properties of CVD microcrystalline diamond films grown on steel substrates. A chromium-nitride (Cr-N) interlayer had been previously proposed to serve as a buffer for carbon and iron inter-diffusion and as a matching layer for the widely differing expansion coefficients of diamond and steel. However, adhesion and wear as well as crystalline perfection of diamond films are strongly affected by conditions of both Cr-N interlayer preparation and CVD diamond deposition. In this work we assess the effects of two parameters. The first one is the temperature of the Cr-N interlayer preparation: temperatures in the range of 500 degrees C-800 degrees C were used. The second one is diamond film thickness in the 0.5 microm-2 microm range monitored through variation of the deposition time from approximately 30 min to 2 hours. The mechanical properties of so deposited diamond films were investigated. For this purpose, scratch tests were performed at different indentation loads. The friction coefficient and wear loss were assessed. The mechanical and tribological properties were related to structure, composition, and crystalline perfection of diamond films which were extensively analyzed using different microscopic and spectroscopic techniques. It was found that relatively thick diamond film deposited on the Cr-N interlayer prepared at the temperature similar to that of the CVD process has the best mechanical and adhesion strength. This film was stable without visible cracks around the wear track during all scratch tests with different indentation loads. In other cases, cracking and delamination of the films took place at low to moderate indentation loads. PMID:22097564

Laikhtman, A; Rapoport, L; Perfilyev, V; Moshkovich, A; Akhvlediani, R; Hoffman, A

2011-09-01

300

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

301

Time Perspective and Causal Attributions for Achievement  

ERIC Educational Resources Information Center

This study examines the relationship between adolescents' time perspective and attributions for achievement. Measures of time perspective (continuity, optimism, pessimism, and utilization) and attributions (ability, effort, context, and luck) independently assessed for success and failure were administered to 10th graders. Implications for…

Wolf, Fredric M.; Savickas, Mark L.

1985-01-01

302

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

ERIC Educational Resources Information Center

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

Geiser, Saul

2009-01-01

303

Micropipe Dissociation through Thick n+ Buffer Layer Growth  

Microsoft Academic Search

Thick (> 25 m) 4H n+ epitaxial layer growth was performed on 4H n+ substrates utilizing chlorine containing etch chemistries in a hot wall CVD system. Optimization of the n+ epitaxial layer growth was achieved by varying C\\/Si ratio and N2 flow. Desired epitaxial layers have doping levels > 5x1018 cm-3, epitaxial surface roughness <10 nm on a 20x20 m

Mike F. MacMillan; Edward K. Sanchez; Michael Dudley; Yi Chen; Mark J. Loboda

2009-01-01

304

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

305

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

306

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

307

Schools Achieving Gender Equity.  

ERIC Educational Resources Information Center

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

Revis, Emma

308

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

309

Advancing Student Achievement  

ERIC Educational Resources Information Center

For the last half century, higher spending and many modern reforms have failed to raise the achievement of students in the United States to the levels of other economically advanced countries. A possible explanation, says Herbert Walberg, is that much current education theory is ill informed about scientific psychology, often drawing on fads and…

Walberg, Herbert J.

2010-01-01

310

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.

311

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

312

Charter School Achievement Studies  

Microsoft Academic Search

A study on charter school performance always makes for a good news story. Unfortunately, like many press reports on medicine and other scientific issues, stories about student achievement in charter schools are premature and often misleading. Americans are just now starting to ask tough questions about the effectiveness of particular schools and to keep and analyze the hard data needed.

Paul T. Hill; Lawrence Angel; Jon Christensen

2006-01-01

313

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

314

Reducing the Achievement Gap.  

ERIC Educational Resources Information Center

Reviews the College Board's report, "Reaching the Top," which addresses educational underrepresentation of high-achieving minority students, examining how social sciences, psychology, and education research contribute to an understanding of the feasibility of the report's recommendations and noting implications of these recommendations for future…

McCombs, Barbara L.

2000-01-01

315

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

316

Bilingualism and Academic Achievement  

ERIC Educational Resources Information Center

Using the Early Childhood Longitudinal Study, Kindergarten Cohort, this study examines the role that bilingualism plays in children's academic developmental trajectories during their early school years, with particular attention on the school environment (N = 16,380). Growth-curve results showed that despite starting with lower math scores in…

Han, Wen-Jui

2012-01-01

317

Achieving Zero Net Migration.  

ERIC Educational Resources Information Center

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

Mann, Donald

1984-01-01

318

Exhibiting Authentic Achievement  

ERIC Educational Resources Information Center

Exhibitions are among the performance-based assessment methods that benefit students and educators. Students gain a sense of their capabilities and areas for growth and emerge better prepared for the future by completing projects and exhibitions that replicate the kinds of open-ended challenges faced by people working in a field of study. Through…

Davidson, Jill

2008-01-01

319

Bridgman crystal growth  

NASA Technical Reports Server (NTRS)

The objective of this theoretical research effort was to improve the understanding of the growth of Pb(x)Sn(1-x)Te and especially how crystal quality could be improved utilizing the microgravity environment of space. All theoretical growths are done using the vertical Bridgman method. It is believed that improved single crystal yields can be achieved by systematically identifying and studying system parameters both theoretically and experimentally. A computational model was developed to study and eventually optimize the growth process. The model is primarily concerned with the prediction of the thermal field, although mass transfer in the melt and the state of stress in the crystal were of considerable interest. The evolution is presented of the computer simulation and some of the important results obtained. Diffusion controlled growth was first studied since it represented a relatively simple, but nontheless realistic situation. In fact, results from this analysis prompted a study of the triple junction region where the melt, crystal, and ampoule wall meet. Since microgravity applications were sought because of the low level of fluid movement, the effect of gravitational field strength on the thermal and concentration field was also of interest. A study of the strength of coriolis acceleration on the growth process during space flight was deemed necessary since it would surely produce asymmetries in the flow field if strong enough. Finally, thermosolutal convection in a steady microgravity field for thermally stable conditions and both stable and unstable solutal conditions was simulated.

Carlson, Frederick

1990-01-01

320

High-pressure refolding of human vascular endothelial growth factor (VEGF) recombinantly expressed in bacterial inclusion bodies: refolding optimization, and feasibility assessment.  

PubMed

High-pressure has been established as an effective technique for refolding proteins at high concentrations. In this study, high hydrostatic pressure (1-3 kbar) was utilized to refold a homodimeric protein from inclusion bodies and the process was evaluated for large-scale manufacturing feasibility. This research focused on increasing protein concentration while maximizing yield and product quality. Refolding yields of 29-42% were achieved in the absence of urea at 2 kbar and at a protein concentration of 6 g/L. Optimization of the refolding buffer composition via multivariate design of experiments and other process parameters such as refolding pressure, gas sparging, and time under pressure are discussed. Although high-pressure refolding can be considered a viable technology for manufacturing if the gains are clearly identified, in this particular case, the benefits that the high-pressure technology offers do not compensate for the drawbacks of implementing new equipment in an existing facility, and unknown impact of scale-up for this molecule. PMID:21608142

Cothran, Amber; St John, Richard J; Schmelzer, Charles H; Pizarro, Shelly A

2011-01-01

321

Administration of the optimized ?-Lapachone-poloxamer-cyclodextrin ternary system induces apoptosis, DNA damage and reduces tumor growth in a human breast adenocarcinoma xenograft mouse model.  

PubMed

?-Lapachone (?-Lap) is a 1,2-orthonaphthoquinone that selectively induces cell death in human cancer cells through NAD(P)H:quinone oxidoreductase-1 (NQO1). NQO1 is overexpressed in a variety of tumors, as compared to normal adjacent tissue. However, the low solubility and non-specific distribution of ?-Lap limit its suitability for clinical assays. We formulated ?-Lap in an optimal random methylated-?-cyclodextrin/poloxamer 407 mixture (i.e., ?-Lap ternary system) and, using human breast adenocarcinoma MCF-7 cells and immunodeficient mice, performed in vitro and in vivo evaluation of its anti-tumor effects on proliferation, cell cycle, apoptosis, DNA damage, and tumor growth. This ternary system is fluid at room temperature, gels over 29 °C, and provides a significant amount of drug, thus facilitating intratumoral delivery, in situ gelation, and the formation of a depot for time-release. Administration of ?-Lap ternary system to MCF-7 cells induces an increase in apoptosis and DNA damage, while producing no changes in cell cycle. Moreover, in a mouse xenograft tumor model, intratumoral injection of the system significantly reduces tumor volume, while increasing apoptosis and DNA damage without visible toxicity to liver or kidney. These anti-tumoral effects and lack of visible toxicity make this system a promising new therapeutic agent for breast cancer treatment. PMID:23333901

Seoane, Samuel; Díaz-Rodríguez, Patricia; Sendon-Lago, Juan; Gallego, Rosalia; Pérez-Fernández, Román; Landin, Mariana

2013-08-01

322

Junior Achievement Student Center  

NSDL National Science Digital Library

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

323

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

324

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

325

Achieving price stability: a 1993 report card  

Microsoft Academic Search

The primary goal of Federal Reserve monetary policy is to foster maximum sustainable growth in the U.S. economy by achieving price stability over time. Although considerable progress toward price stability has been made since the early 1980s, inflation remains above the level most analysts would associate with price stability. Because price stability is the key contribution the Federal Reserve can

George A. Kahn

1994-01-01

326

Molecular Beam Epitaxial Growth of InP Using a Valved Phosphorus Cracker Cell: Optimization of Electrical, Optical and Surface Morphology Characteristics  

NASA Astrophysics Data System (ADS)

We report the molecular beam epitaxial (MBE) growth of epitaxial InP using a valved phosphorous cracker cell at a range of cracking zone temperature (Tcr=875°C to 950°C), V/III flux ratio (V/III=1.2 to 9.3) and substrate temperature (Ts=360°C to 500°C). From Hall measurements, the as-grown epitaxial InP on InP (100) substrate was found to be n-type. The background electron concentration and mobility exhibited a pronounced dependence on the cracking zone temperature, V/III flux ratio and substrate temperature. Using a cracking zone temperature of 850°C, the highest 77 K electron mobility of 40900 cm2/Vs was achieved at a V/III ratio of 2.3 at a substrate temperature (Ts) of 440°C. The corresponding background electron concentration was 1.74×1015 cm-3. The photoluminescence (PL) spectra showed two prominent peaks at 1.384 eV and 1.415 eV, with the intensity of the low-energy peak becoming stronger at higher cracking zone temperatures. The surface morphology deteriorated following a reduction in the V/III ratio or an increase in the substrate temperature. In the extreme case, formation of free indium droplets and severe surface faceting occurred.

Yoon, Soon; Zheng, Hai; HuaZhang, Peng; Mah, Kia; Ng, Geok

1999-02-01

327

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

328

Student Achievement, Personal Achievement Goal Orientations, and Perceptions of Classroom Goal Structures in a Standards-Based Reporting System  

ERIC Educational Resources Information Center

The purpose of this study was to analyze student achievement growth and motivational goal orientations in a standards-based reporting environment in a rural SC school district. More specifically, this study sought to determine if student achievement growth is related to the number of years students received standards-based reports in middle…

Ballard, Amy Copeland

2010-01-01

329

Growth of Al x Ga 1? x N (0 < = x < = 0.2) and fabrication of AlGaN\\/GaN superlattice by RF-source MBE  

Microsoft Academic Search

Based on the two-step growth, GaN and AlGaN on sapphire (0001) were grown by MBE using an RF-source. We have attained a very flat growing surface by optimizing growth conditions both for the buffer layer and the main growth. We also grew AlGaN\\/GaN superlattices to demonstrate the flatness achieved on the growth surface. From X-ray diffraction and transmission electron microscopy

Kazuhiko Nozawa; Narihiko Maeda; Yoshiro Hirayama; Naoki Kobayashi

1998-01-01

330

Achievement in Physics  

NASA Astrophysics Data System (ADS)

Naomi Moran, a student at the Arnewood School, New Milton, Hampshire was the first recipient of the `Achievement in Physics' prize awarded by the South Central Branch of The Institute of Physics. Naomi received an award certificate and cheque for £100 from Dr Ruth Fenn, Chairman of the Branch, at the annual Christmas lecture held at the University of Surrey in December. She is pictured with Dr Fenn and Steve Beith, physics teacher at the Arnewood School.  Photo Figure 1. Naomi Moran receiving her award (photograph courtesy of Peter Milford). The award is intended to celebrate personal achievement in physics at any level at age 16-17 and is not restricted to those who gain the highest academic results. Schools across the county were invited to nominate suitable candidates; Naomi's nomination by the school's deputy head of science impressed the judges because of her ability to grasp the most difficult parts of the subject quickly, in addition to the fact that she took her AS-level science in year 11 when she was only 16. She is currently studying A-level physics, chemistry and mathematics and hopes to continue her studies at university later this year.

1999-03-01

331

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

332

RF Gun optimization study  

Microsoft Academic Search

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

A. Hofler; Pavel Evtushenko; M. Krasilnikov

2007-01-01

333

Project planning through optimization  

Microsoft Academic Search

Summary form only given as follows. Projects exposed to an uncertain environment must deal with effective integration of various planning elements and optimization of project parameters. Time cost and quality are the prime objectives of a project that are to be optimized to fulfil the objective of project achievement. Moreover, in uncertain environments, there exists a lot of other conflicting

P. K. Dey; S. Mukherjee; A. Bhattacharya

1997-01-01

334

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

335

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

336

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.

337

HEPEX - achievements and challenges!  

NASA Astrophysics Data System (ADS)

HEPEX is an international initiative bringing together hydrologists, meteorologists, researchers and end-users to develop advanced probabilistic hydrological forecast techniques for improved flood, drought and water management. HEPEX was launched in 2004 as an independent, cooperative international scientific activity. During the first meeting, the overarching goal was defined as: "to develop and test procedures to produce reliable hydrological ensemble forecasts, and to demonstrate their utility in decision making related to the water, environmental and emergency management sectors." The applications of hydrological ensemble predictions span across large spatio-temporal scales, ranging from short-term and localized predictions to global climate change and regional modeling. Within the HEPEX community, information is shared through its blog (www.hepex.org), meetings, testbeds and intercompaison experiments, as well as project reportings. Key questions of HEPEX are: * What adaptations are required for meteorological ensemble systems to be coupled with hydrological ensemble systems? * How should the existing hydrological ensemble prediction systems be modified to account for all sources of uncertainty within a forecast? * What is the best way for the user community to take advantage of ensemble forecasts and to make better decisions based on them? This year HEPEX celebrates its 10th year anniversary and this poster will present a review of the main operational and research achievements and challenges prepared by Hepex contributors on data assimilation, post-processing of hydrologic predictions, forecast verification, communication and use of probabilistic forecasts in decision-making. Additionally, we will present the most recent activities implemented by Hepex and illustrate how everyone can join the community and participate to the development of new approaches in hydrologic ensemble prediction.

Pappenberger, Florian; Ramos, Maria-Helena; Thielen, Jutta; Wood, Andy; Wang, Qj; Duan, Qingyun; Collischonn, Walter; Verkade, Jan; Voisin, Nathalie; Wetterhall, Fredrik; Vuillaume, Jean-Francois Emmanuel; Lucatero Villasenor, Diana; Cloke, Hannah L.; Schaake, John; van Andel, Schalk-Jan

2014-05-01

338

Students' Goal Achievement: Exploring Individual and Situational Factors  

ERIC Educational Resources Information Center

Introduction: This paper reports a preliminary investigation of the individual and situational factors affecting goal achievement in a psychology student population. The impact of normative information on goal achievement is considered in relation to goal commitment, optimism, gender and academic setting. Method: Psychology students (n=121) from…

Derrer-Rendall, Nicola; Wesson, Caroline; Anderson, Lindsey; Bould, Emma

2009-01-01

339

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

340

Earning the Stamp of Approval: How To Achieve Optimal Usability.  

ERIC Educational Resources Information Center

Describes the redesign of the Web site at the virtual library of the NIST (National Institute of Standards and Technology). Discusses usability problems with the original site, including navigation difficulties; focus groups to determine user needs; usability testing for the new Web site; and the importance of customer input. (LRW)

Makar, Susan

2003-01-01

341

Denver airport pumping systems achieve optimal [Delta] T's  

SciTech Connect

This article describes how the pumping and generating systems at the new Denver Airport operate efficiently with the user loops in the buildings producing design temperature rise at all load levels. Fifteen miles east of Denver's Stapleton International Airport lies the newly completed Denver International Airport (DIA)--the world's largest and most high-tech airport. Besides being one of the largest construction projects in the works, it has many of the latest technical innovations available. Of particular interest to the HVAC industry is the design of the heating and cooling water systems. These systems provide environmental cooling and heating water to the three concourses, the airport office building, and the main terminal. The mechanical engineers for the project were all from the Denver area. The central plant design was the work of Behrent Engineering Co.; the three concourses were designed by Swanson-Rink Associates; and the main terminal and administrative office building were designed by Abeyta Engineering Consultants. The overall system concept was developed during the initial design phase by engineers from these firms, members of the DIA staff, and application engineers from several manufacturers.

Mannion, G.F.; Krist, G.D. (BRDG-TNDR Corp., Fort Lauderdale, FL (United States))

1994-07-01

342

Achieving Near-Optimal Sensor Allocation Policies Through Reinforcement Learning.  

National Technical Information Service (NTIS)

TACTICAL AIRCRAFT MUST FREQUENTLY PERFORM COMPLEX SEQUENTIAL TASKS IN WHICH THEY RELY HEAVILY ON THE INTEGRATION OF SENSORY DATA TO ASSESS STATE AND MAINTAIN SITUATIONAL AWARENESS. IN MODERN SYSTEMS, THE CONTROL OF THE SENSORS' INFORMATION-GATHERING ACTIV...

P. Malhotra

1996-01-01

343

Optimal design of controlled structures  

Microsoft Academic Search

A formulation that finds the optimal design of a controlled structure is proposed. To achieve this goal, a composite objective composed of structural and control objectives is introduced to be optimized, and the effect of the control weighting is examined. A feedback control law is defined before the structural optimization and then the composite objective will only become a function

J.-S. Ou; N. Kikuchi

1996-01-01

344

Social order perspective on raising student achievement  

Microsoft Academic Search

Despite significant and sustained gains recorded on the national secondary school leaving examinations between 1999–2004,\\u000a South Africa’s large-scale secondary school reform has receive little international attention. Defenders of the reforms have\\u000a argued that the ‘success’ in raising student achievement extended beyond gains in the percentage pass rates to include increased\\u000a numbers of students completing secondary schooling, a growth in the

Brahm Fleisch

2008-01-01

345

Characteristics of in-situ phosphorus-doped silicon selective epitaxial growth at atmospheric pressure  

NASA Astrophysics Data System (ADS)

The characteristics of in-situ P-doped Si selective epitaxial growth (SEG) under atmospheric pressure (AP) was investigated and compared with in-situ As-doped SEG under AP. Dopant concentrations and growth rates of films grown at AP are higher than those at low pressure, this for both dopants. This was interpreted as effects of surface segregation of the dopant atoms and the strong etching effect of HCl during the SEG under AP. By optimizing the growth rate and temperature, we achieved a high dopant concentration of 7.3×10 19 atoms/cm 3 and a high growth rate for the P-doped SEG.

Ikuta, Tetsuya; Fujita, Shigeru; Iwamoto, Hayato; Kadomura, Shingo; Shimura, Takayoshi; Watanabe, Heiji; Yasutake, Kiyoshi

2008-10-01

346

Growth following solid organ transplantation in childhood.  

PubMed

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

347

Achievement Motivation Development Project. Final Report. Appendix IV, Part 2.  

ERIC Educational Resources Information Center

The Achievement Motivation Development Project is described. The Project has culminated in the development of course materials designed explicitly to promote aspects of psychological growth. As such, it is viewed as but one thrust in an emerging psychological education movement. Achievement motivation is defined as a way of planning, a set of…

McClelland, David C.; Alschuler, Alfred S.

348

Process validation: achieving the Operational Qualification phase.  

PubMed

The OQ phase of process validation is very important and is where the complete understanding of the process is determined by experimentation. This understanding is useful to: * establish optimal process parameters * understand variation that affect the process * aid in investigating process deviations. OQ is an important part of the entire process validation activity and essential to understanding a manufacturing process. The benefits of completing the OQ and overall process validation are the reasons that it makes business sense and receive the long-term benefits of producing high quality product and achieving customer satisfaction. PMID:15521514

Buffaloe, Vera

2004-01-01

349

To Achieve or Not to Achieve: The Question of Women.  

ERIC Educational Resources Information Center

Questionnaire and projective data from 323 women aged 18 to 50 were analyzed in order to study the relationships of need achievement and motive to avoid success to age, sex role ideology, and stage in the family cycle. Family background and educational variables were also considered. Level of need achievement was found to be significantly related…

Gilmore, Beatrice

350

Attribution theory in science achievement  

NASA Astrophysics Data System (ADS)

Recent research reveals consistent lags in American students' science achievement scores. Not only are the scores lower in the United States compared to other developed nations, but even within the United States, too many students are well below science proficiency scores for their grade levels. The current research addresses this problem by examining potential malleable factors that may predict science achievement in twelfth graders using 2009 data from the National Assessment of Educational Progress (NAEP). Principle component factor analysis was conducted to determine the specific items that contribute to each overall factor. A series of multiple regressions were then analyzed and formed the predictive value of each of these factors for science achievement. All significant factors were ultimately examined together (also using multiple regression) to determine the most powerful predictors of science achievement, identifying factors that predict science achievement, the results of which suggested interventions to strengthen students' science achievement scores and encourage persistence in the sciences at the college level and beyond. Although there is a variety of research highlighting how students in the US are falling behind other developing nations in science and math achievement, as yet, little research has addressed ways of intervening to address this gap. The current research is a starting point, seeking to identify malleable factors that contribute to science achievement. More specifically, this research examined the types of attributions that predict science achievement in twelfth grade students.

Craig, Martin

351

Linear quadratic optimal learning control (LQL)  

Microsoft Academic Search

A learning control solution to the problem of finding a finite-time optimal control history that minimizes a quadratic cost is presented. Learning achieves optimization without requiring detailed knowledge of the system, which may be affected by unknown but repetitive disturbances. The optimal solution is synthesized one basis function at a time, reaching optimality in a finite number of trials. These

James A. Frueh; Minh Q. Phan

1998-01-01

352

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

353

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

354

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

355

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

356

Raising Boys' Achievement in Schools.  

ERIC Educational Resources Information Center

This book offers insights into the range of strategies and good practice being used to raise the achievement of boys. Case studies by school-based practitioners suggest ideas and measures to address the issue of achievement by boys. The contributions are: (1) "Why the Likely Lads Lag Behind" (Kevan Bleach); (2) "Helping Boys Do Better in Their…

Bleach, Kevan, Ed.

357

Examination Regimes and Student Achievement  

ERIC Educational Resources Information Center

Examination regimes at the end of secondary school vary greatly intra- and cross-nationally, and in recent years have undergone important reforms often geared towards increasing student achievement. This research presents a comparative analysis of the relationship between examination regimes and student achievement in the OECD. Using a micro…

Cosentino de Cohen, Clemencia

2010-01-01

358

Stress Correlates and Academic Achievement.  

ERIC Educational Resources Information Center

An ongoing concern for educators is the identification of factors that contribute to or are associated with academic achievement; one such group of variables that has received little attention are those involving stress. The relationship between perceived sources of stress and academic achievement was examined to determine if reactions to stress…

Bentley, Donna Anderson; And Others

359

Test Anxiety and Academic Achievement.  

ERIC Educational Resources Information Center

Undoubtedly test anxiety is a troublesome condition found to be prevalent today among college students. Over the years various attempts have been made to explore how test anxiety influences academic achievement. This paper discusses the extent to which test anxiety affects academic achievement of college students, and the techniques found to be…

Chang, Moon K.

360

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

361

Study on optimal growth conditions of a-plane GaN grown on r-plane sapphire by metal-organic chemical vapor deposition  

Microsoft Academic Search

Non-polar a-plane (112¯0) GaN thin films were grown on r-plane (11¯02) sapphire substrates by metal-organic chemical vapor deposition. In order to obtain a-plane GaN films with better crystal quality and surface morphology, detailed comparisons between different growth conditions were investigated. The results showed that high-temperature and low-pressure conditions facilitating two-dimensional growth could lead to a fully coalesced a-plane GaN layer

T. S. Ko; T. C. Wang; R. C. Gao; H. G. Chen; G. S. Huang; T. C. Lu; H. C. Kuo; S. C. Wang

2007-01-01

362

Optimal Weight Gain  

Microsoft Academic Search

Optimal birth weight and outcome are influenced by maternal weight gain. Low gestational weight gain is associated with poor\\u000a fetal growth and risk of preterm delivery. Excessive weight gain affects infant growth, body fatness in childhood, and the\\u000a potential for postpartum weight retention and future obesity. Guidelines from the Institute of Medicine recommend that a woman\\u000a with a normal body

Grace A. Falciglia; Kristin H. Coppage

363

Distributive Politics and Economic Growth  

Microsoft Academic Search

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

Alberto Alesina

1994-01-01

364

Effective delivery of p65 shRNA by optimized Tween 85-polyethyleneimine conjugate for inhibition of tumor growth and lymphatic metastasis.  

PubMed

To maximize the interference efficacy of pGPU6/Neo-p65 shRNA-expressing pDNA (p65 shRNA) and subsequently more effectively inhibit tumor growth and lymphatic metastasis through blocking the nuclear factor-kappa B (NF-?B) signaling pathway, seven Tween 85-polyethyleneimine (PEI) conjugates (TnPs, n=2, 3, 4, 5, 6, 7 and 8), which differed in the length of the polymethylene [-(CH2)n-] spacer between Tween 85 and PEI, were synthesized and investigated. The results showed that the transfection efficiency and cytotoxicity both increased with the spacer chain length. Then, TnPs with a [-(CH2)6-] spacer (T6P) were chosen to deliver p65 shRNA to a tumor and subsequently inhibit tumor growth and lymphatic metastasis. The T6P/p65 shRNA complex nanoparticles (T6Ns) could significantly down-regulate p65 expression in breast cancer cells, and consequently inhibit cell invasion and disrupt the tube formation. Most importantly, T6Ns accumulated greatly in tumor tissue, and as a result, significantly inhibited the growth and lymphatic metastasis of breast cancer xenograft. All these results indicated that the transfection efficacies of cationic amphiphiles could be significantly modulated by minor structural variations, and that T6P was promising for the effective delivery of p65 shRNA to knock down the expression of the key metastasis-driving genes and inhibit tumor growth and metastasis. PMID:24525035

Xiao, Jisheng; Duan, Xiaopin; Meng, Qingshuo; Yin, Qi; Zhang, Zhiwen; Yu, Haijun; Chen, Lingli; Gu, Wangwen; Li, Yaping

2014-06-01

365

Physical vapor transport growth of aluminum nitride  

NASA Astrophysics Data System (ADS)

Conventional III:nitride devices are grown on sapphire or SiC. This heterogeneous growth induces significant performance limiting aspects, such as stress and high dislocation densities for the resultant devices. Physical Vapor Transport (PVT) growth of AlN was investigated to produce free standing crystals suitable for homogenous substrate use. AlN bulk single crystals were grown by spontaneous nucleation on the side wall of a Hot Pressed BN (HPBN) crucible, using both commercial Al metal and AlN powder as source materials in an open system to produce a-plane crystal platelet. The crystals had low (11-20) o rocking curves with full-width at half-maximum values of 17-60 arcsecs, indicative of their high crystalline quality. Furthermore, the addition of 1% indium by weight to the source material was found to significantly influence growth and nucleation site formation. Despite their high quality, the crystals could not be scaled for substrate use because of the limited size and morphology of the crystals. Hot Pressed TaC (HP-TaC) crucibles were fabricated in house by sintering TaC powder in a hot press furnace. The resulting crucibles were stable for several hundred hours at growth temperatures in excess of 2300°C. The resulting AlN growth in the HP-TaC crucibles produced a polycrystalline boule. Grain growth was obtained in a single growth, however further optimization was required to control spontaneous nucleation site formation during the initial stage of a regrowth. Continuous grain growth was achieved by controlling oxygen contaminants which allowed the production of a single grain with a horizontal cross-section 23 mm2 in size. Methods to support seed crystals were developed and seeded growth was attempted to allow the growth of substrates suitable for device growth.

Letts, Edward Robert

366

Treatment of Escherichia coli O157:H7 with lactic acid, neutralized electrolyzed oxidizing water and chlorine dioxide followed by growth under sub-optimal conditions of temperature, pH and modified atmosphere.  

PubMed

The utilization of sub-lethal decontamination treatments gains more and more interest due to the increased consumers' demand for fresh, minimally processed and convenient food products. These products rely on cold chain and hurdle (combination) technology to provide microbiological safety and quality during their shelf life. To investigate the ability of surviving cells to resuscitate and grow in a food simulating environment, sub-lethal decontamination treatments were coupled with subsequent storage under sub-optimal growth conditions. For this purpose chlorine dioxide (ClO2) and neutralized electrolyzed oxidizing water (NEW)-treated cultures of Escherichia coli O157:H7 were inoculated in TSB-YE of pH 5.8 and aw 0.99, and stored at 10 degrees C, 12.5 degrees C and 15 degrees C, under four different atmospheres (0%, 30% and 60% CO2 balanced with N2, and air). Due to the severity of injury, lactic acid-treated cells were inoculated in TSB-YE pH 7.0. Data obtained reveal that the fraction of sub-lethally injured E. coli O157:H7 undergoes an additional inhibitory effect during the storage period under of sub-optimal conditions. Observed extension in the lag growth phase was a direct consequence prior sub-lethal injury. The effects of liquid ClO2 and NEW were less pronounced in comparison to lactic acid. The current study signifies the potential utilization of appropriate combination of different extrinsic and intrinsic factors in the elimination or growth inhibition of food-borne pathogens. PMID:19527839

Smigic, Nada; Rajkovic, Andreja; Antal, Eszter; Medic, Helga; Lipnicka, Barbara; Uyttendaele, Mieke; Devlieghere, Frank

2009-09-01

367

MOVPE growth of AlGaN\\/GaN superlattices on ZnO substrates for green emitter applications  

Microsoft Academic Search

AlGaN\\/GaN superlattice structures have been deposited on (0001) ZnO substrates by metalorganic vapor phase epitaxy. The growth conditions were first optimized on GaN templates using N2 as carrier gas at relatively low temperature (<800°C), which is suitable for GaN growth on a ZnO substrate. Experimental results show that high interfacial quality can be achieved in the superlattice by using TMIn

Hongbo Yu; Shenjie Wang; Nola Li; William Fenwick; Andrew Melton; B. Klein; Ian Ferguson

2008-01-01

368

Using Design To Achieve Sustainability  

EPA Science Inventory

Sustainability is defined as meeting the needs of this generation without compromising the ability of future generations to meet their needs. This is a conditional statement that places the responsibility for achieving sustainability squarely in hands of designers and planners....

369

Achieving Standards through Environmental Education.  

ERIC Educational Resources Information Center

Most states do not have the time or resources to develop environmental education standards from scratch. Highlights the role that environmental education and its interdisciplinary nature can play in helping students achieve. (DDR)

Kaspar, Mike

1999-01-01

370

CRPV genomes with synonymous codon optimizations in the CRPV E7 gene show phenotypic differences in growth and altered immunity upon E7 vaccination.  

PubMed

Papillomaviruses use rare codons relative to their hosts. Recent studies have demonstrated that synonymous codon changes in viral genes can lead to increased protein production when the codons are matched to those of cells in which the protein is being expressed. We theorized that the immunogenicity of the virus would be enhanced by matching codons of selected viral genes to those of the host. We report here that synonymous codon changes in the E7 oncogene are tolerated in the context of the cottontail rabbit papillomavirus (CRPV) genome. Papilloma growth rates differ depending upon the changes made indicating that synonymous codons are not necessarily neutral. Immunization with wild type E7 DNA yielded significant protection from subsequent challenge by both wild type and codon-modified genomes. The reduction in growth was most dramatic with the genome containing the greatest number of synonymous codon changes. PMID:18698362

Cladel, Nancy M; Hu, Jiafen; Balogh, Karla K; Christensen, Neil D

2008-01-01

371

High volumetric yields of functional dimeric miniantibodies in Escherichia coli , using an optimized expression vector and high-cell-density fermentation under non-limited growth conditions  

Microsoft Academic Search

Functional bivalent miniantibodies, directed against the epidermal growth factor receptor, accumulated to more than 3 gl?1 in high-cell-density cultures of Escherichia coli RV308(pHKK) on a pilot scale. The miniantibodies consist of scFv fragments with a C-termi-nal hinge followed by a helix-turn-helix\\u000a motif, which homodimerizes in vivo. The improved expression vector pHKK is characterized by the hok\\/sok suicide system, improving plasmid

U. Horn; W. Strittmatter; A. Krebber; U. Knüpfer; M. Kujau; R. Wenderoth; K. Müller; S. Matzku; A. Plückthun; D. Riesenberg

1996-01-01

372

Optimizing Conditions for the Growth ofLactobacillus casei YIT 9018 in Tryptone-Yeast Extract-Glucose Medium by Using Response Surface Methodology  

Microsoft Academic Search

This study was undertaken to find optimum conditions of tryptone, yeast extract, glucose, Tween 80, and incubation temperature for the growth ofLactobacillus caseiYIT 9018 and to assess the effects of these factors by use of response surface methodology. A central composite design was used as an experimental design for allocation of treatment combinations. A second-order polynomial regression model, which was

SEJONG OH; SUNGSUE RHEEM; JAEHUN SIM; SANGKYO KIM; ANDYOUNGJIN BAEK

1995-01-01

373

Optimization of (1 1 2¯ 0) a-plane GaN growth by MOCVD on (1 1¯ 0 2) r-plane sapphire  

NASA Astrophysics Data System (ADS)

A-plane GaN (1 1 2¯ 0) epilayers have been grown on r-plane (1 1¯ 0 2) sapphire by MOCVD, and investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and atomic force microscopy (AFM). This particular orientation is non-polar, as opposed to the c-direction, and avoids polarization charge and the associated screening charge, and the consequent band bending. Our results showed that low pressure, low ammonia flow rate (namely low V/III ratio), high-temperature conditions lead to fully coalesced and relatively high crystalline-quality a-plane GaN films. Both low-temperature GaN buffer and high-temperature AlN buffer were used for a-plane GaN growth on r-plane sapphire, and produced similar crystalline quality and surface morphology. Surface morphological evolution during early stages of a-plane GaN growth revealed behavior different from that of c-plane GaN growth. The possible reasons for striped features and surface undulations of a-plane GaN are discussed.

Ni, X.; Fu, Y.; Moon, Y. T.; Biyikli, N.; Morkoç, H.

2006-04-01

374

Dextrous hand grasping force optimization  

Microsoft Academic Search

A key goal in dextrous robotic hand grasping is to balance external forces and at the same time achieve grasp stability and minimum grasping energy by choosing an appropriate set of internal grasping forces. Since it appears that there is no direct algebraic optimization approach, a recursive optimization, which is adaptive for application in a dynamic environment, is required. One

Martin BUSS; Hideki Hashimoto; John B. Moore

1996-01-01

375

Supply-Chain Optimization Template  

NASA Technical Reports Server (NTRS)

The Supply-Chain Optimization Template (SCOT) is an instructional guide for identifying, evaluating, and optimizing (including re-engineering) aerospace- oriented supply chains. The SCOT was derived from the Supply Chain Council s Supply-Chain Operations Reference (SCC SCOR) Model, which is more generic and more oriented toward achieving a competitive advantage in business.

Quiett, William F.; Sealing, Scott L.

2009-01-01

376

Maximum Fruit Growth Potential Following Resource Limitation During Peach Growth  

Microsoft Academic Search

To achieve its maximum organ growth potential, an organ must grow at its potential relative growth rate (RGR) throughout development. When resource availability limits growth, the RGR is reduced below the potential RGR. This study examines whether, following a period of resource-limited growth, the RGR is able to increase to the potential RGR when sufficient resources are available. Fruit RGRs

Yaffa L. Grossman; Theodore M. DeJong

1995-01-01

377

Optimal adaptive management for the translocation of a threatened species.  

PubMed

Active adaptive management (AAM) is an approach to wildlife management that acknowledges our imperfect understanding of natural systems and allows for some resolution of our uncertainty. Such learning may be characterized by risky strategies in the short term. Experimentation is only considered acceptable if it is expected to be repaid by increased returns in the long term, generated by an improved understanding of the system. By setting AAM problems within a decision theory framework, we can find this optimal balance between achieving our objectives in the short term and learning for the long term. We apply this approach to managing the translocation of the bridled nailtail wallaby (Onychogalea fraenata), an endangered species from Queensland, Australia. Our task is to allocate captive-bred animals, between two sites or populations to maximize abundance at the end of the translocation project. One population, at the original site of occupancy, has a known growth rate. A population potentially could be established at a second site of suitable habitat, but we can only learn the growth rate of this new population by monitoring translocated animals. We use a mathematical programming technique called stochastic dynamic programming, which determines optimal management decisions for every possible management trajectory. We find optimal strategies under active and passive adaptive management, which enables us to examine the balance between learning and managing directly. Learning is more often optimal when we have less prior information about the uncertain population growth rate at the new site, when the growth rate at the original site is low, and when there is substantial time remaining in the translocation project. Few studies outside the area of optimal harvesting have framed AAM within a decision theory context. This is the first application to threatened species translocation. PMID:19323207

Rout, Tracy M; Hauser, Cindy E; Possingham, Hugh P

2009-03-01

378

Advanced dendritic web growth development  

NASA Technical Reports Server (NTRS)

Computer specifications for low stress dendritic crystal web growth configurations having thermal elements in fixed positions were developed, as well as computer specifications for web growth incorporating dynamic positioning of thermal elements. Low buckling stress with increased width of unbuckled growth was sought, as well as increased growth velocity while maintaining low residual stress. Model-defined advanced concepts for web growth configurations were defined and verified in experimental web growth. Major increases were achieved in width and velocity.

Duncan, C. S.

1984-01-01

379

Adaptive Instruction and Pupil Achievement.  

ERIC Educational Resources Information Center

Examines effects of adaptive instruction on results of 456 children in the first year of reading instruction at 23 Dutch primary schools. Teachers in the experimental group show significantly higher adaptive instructional behaviors (optimizing time on task and using direct instruction and phonics methods) than control-group teachers. (59…

Houtveen, A. A. M.; Booji, N.; de Jong, R.; Grift, W. J. C. M. van de

1999-01-01

380

Optimization of growth of ternary CuInS 2 thin films by ionic reactions in alkaline chemical bath as n-type photoabsorber layer  

Microsoft Academic Search

Thin films of n-type CuInS2 (CIS) have been grown onto a indium–tin-oxide glass substrates using the ionic reactions in alkaline chemical bath at 40°C temperature. The alkaline cationic and anionic in single precursor solution is obtained by dissolving CuSO4 (0.02M), InCl3 (0.02M), citric acid (0.05M) and NH2–CS–NH2 (0.02M) in deionized water at higher pH value (11). In order to achieve

Ramphal Sharma; Suyeon Shim; Rajaram S. Mane; T. Ganesh; Anil Ghule; Gangri Cai; Duk-Ho Ham; Sun-Ki Min; Wonjoo Lee; Sung-Hwan Han

2009-01-01

381

Sex Differences in Attribution of Achievement and Actual Achievement.  

ERIC Educational Resources Information Center

One-hundred-seventy-six male and 116 female college freshmen took part in a questionnaire study of sex differences in attribution of achievemnt. Achievement was operationalized as grade point index, a performance measure of significance to the subjects, where success-failure feedback is contingent on one's own performance. The best predictor of…

Erkut, Sumru

382

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

383

Rapid Selection of Optimal Formulations for Divergent Clones Through Screening Chinese Hamster Ovary Media Library  

Microsoft Academic Search

\\u000a The successful culture of Chinese Hamster Ovary (CHO) cells can be a challenging endeavor. Historical data shows that CHO\\u000a clones have diverse nutritive requirements. Selecting a medium designed specifically for a CHO cell line is a key component\\u000a for achieving optimal growth and productivity. With the wide variety of media available, narrowing the number of formulations\\u000a for screening can be

Avril A. Lawshé; Min Zhang; Ashley Smith; Wade Nudson; James S. Ross; Matthew V. Caple

384

Population growth and economic growth.  

PubMed

This discussion of the issues relating to the problem posed by population explosion in the developing countries and economic growth in the contemporary world covers the following: predictions of economic and social trends; the Malthusian theory of population; the classical or stationary theory of population; the medical triage model; ecological disaster; the Global 2000 study; the limits to growth; critiques of the Limits to Growth model; nonrenewable resources; food and agriculture; population explosion and stabilization; space and ocean colonization; and the limits perspective. The Limits to Growth model, a general equilibrium anti-growth model, is the gloomiest economic model ever constructed. None of the doomsday models, the Malthusian theory, the classical stationary state, the neo-Malthusian medical triage model, the Global 2000 study, are so far reaching in their consequences. The course of events that followed the publication of the "Limits to Growth" in 1972 in the form of 2 oil shocks, food shock, pollution shock, and price shock seemed to bear out formally the gloomy predictions of the thesis with a remarkable speed. The 12 years of economic experience and the knowledge of resource trends postulate that even if the economic pressures visualized by the model are at work they are neither far reaching nor so drastic. Appropriate action can solve them. There are several limitations to the Limits to Growth model. The central theme of the model, which is overshoot and collapse, is unlikely to be the course of events. The model is too aggregative to be realistic. It exaggerates the ecological disaster arising out of the exponential growth of population and industry. The gross underestimation of renewable resources is a basic flaw of the model. The most critical weakness of the model is its gross underestimation of the historical trend of technological progress and the technological possiblities within industry and agriculture. The model does correctly emphasize the exponential growth of population as the source of several complications for economic growth and human welfare. Stabilization of population by reducing fertility is conducive for improving the quality of population and also advances the longterm management of the population growth and work force utilization. The perspective of longterm economic management involves populatio n planning, control of environmental pollution, conservation of scarce resources, exploration of resources, realization of technological possibilities in agriculture and industry and in farm and factory, and achievement of economic growth and its equitable distribution. PMID:12314595

Narayana, D L

1984-01-01

385

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.

2013-01-01

386

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

387

Conserved histidine of metal transporter AtNRAMP1 is crucial for optimal plant growth under manganese deficiency at chilling temperatures.  

PubMed

Manganese (Mn) is an essential nutrient required for plant growth, in particular in the process of photosynthesis. Plant performance is influenced by various environmental stresses including contrasting temperatures, light or nutrient deficiencies. The molecular responses of plants exposed to such stress factors in combination are largely unknown. Screening of 108 Arabidopsis thaliana (Arabidopsis) accessions for reduced photosynthetic performance at chilling temperatures was performed and one accession (Hog) was isolated. Using genetic and molecular approaches, the molecular basis of this particular response to temperature (G × E interaction) was identified. Hog showed an induction of a severe leaf chlorosis and impaired growth after transfer to lower temperatures. We demonstrated that this response was dependent on the nutrient content of the soil. Genetic mapping and complementation identified NRAMP1 as the causal gene. Chlorotic phenotype was associated with a histidine to tyrosine (H239Y) substitution in the allele of Hog NRAMP1. This led to lethality when Hog seedlings were directly grown at 4°C. Chemical complementation and hydroponic culture experiments showed that Mn deficiency was the major cause of this G × E interaction. For the first time, the NRAMP-specific highly conserved histidine was shown to be crucial for plant performance. PMID:24571269

Ihnatowicz, Anna; Siwinska, Joanna; Meharg, Andrew A; Carey, Manus; Koornneef, Maarten; Reymond, Matthieu

2014-06-01

388

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

389

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

390

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

391

Optimal disturbances in pipe flows  

Microsoft Academic Search

The growth of optimal disturbances in pipe Poiseuille flow and in a rotating pipe is investigated. In pipe Poiseuille flow the role of a pair of nearly parallel least stable modes, as a key element of the transient growth mechanism, is explored. Temporal and spatial disturbances are analyzed. The time and distance, at which the maximum energy amplification of an

Guy Ben-Dov; Jacob Cohen

2004-01-01

392

Achieving Results in MBA Communication.  

ERIC Educational Resources Information Center

Describes how Rice University's Jones Graduate School of Management achieves their mission for the communication program. Discusses three keys to the success of the program: individual coaching, integrated team instruction, and constant assessment of the students and the program. Presents an overview of the program. (SG)

Barrett, Deborah J.

2002-01-01

393

Hispanic Student Achievement. Research Brief  

ERIC Educational Resources Information Center

What are the factors affecting the achievement of Hispanic high school youth? Hispanic Americans are the largest growing population in the United States. Currently, Hispanic students make up more than 20% of the U.S. school population and, in 23 of the 50 states, Hispanic students outnumber African American and Asian students. During the 1970s and…

Hansen, Angela L.

2005-01-01

394

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

395

Teachers, Schools, and Academic Achievement  

Microsoft Academic Search

This paper disentangles the impact of schools and teachers in influencing achievement with special attention given to the potential problems of omitted or mismeasured variables and of student and school selection. Unique matched panel data from the UTD Texas Schools Project permit the identification of teacher quality based on student performance along with the impact of specific, measured components of

Steven G. Rivkin; Eric A. Hanushek; John F. Kain

2002-01-01

396

Student Achievement: Improving Our Focus.  

ERIC Educational Resources Information Center

An efficient way to help students achieve academically is to maximize the consistent attendance of permanent teachers in the classroom. Students nationwide are spending increased amounts of time with instructors other than their permanent teachers. A large contributor to the problem of teacher absenteeism is mandatory leave for professional…

Hawkins, Amber

397

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

398

Using Calculators on Achievement Tests.  

ERIC Educational Resources Information Center

Discussed are experiences in using the calculator to assess mathematical understanding on the Missouri Mastery and Achievement Tests (MMAT). Data from a calculator group and a no-calculator group at the eighth- and tenth-grade levels are reported. Several items showed differences between groups. (YP)

Long, Vena M.; And Others

1989-01-01

399

Achieving world class maintenance status  

SciTech Connect

The article written by a management consultant, discusses the art of successful planning and operation of maintenance in mines considering factors such as benchmaking, key performance indices (KPIs) and frequency of procedures which can help achieve 'world class maintenance'. 1 fig.

Tomlingson, P.D. [Paul D. Tomingson Associates (United States)

2007-08-15

400

The Widening Income Achievement Gap  

ERIC Educational Resources Information Center

Has the academic achievement gap between high-income and low-income students changed over the last few decades? If so, why? And what can schools do about it? Researcher Sean F. Reardon conducted a comprehensive analysis of research to answer these questions and came up with some striking findings. In this article, he shows that income-related…

Reardon, Sean F.

2013-01-01

401

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.

402

Achieving urinary continence in children  

Microsoft Academic Search

Achievement of urinary continence is an important developmental step that most children attain with the assistance of their parents and caregivers. Debate continues as to the best time to toilet train; in some Asian and African cultures children are trained as infants, while training at age 2–3 years is more typical in Western cultures. Infant voiding is not merely a

Hsi-Yang Wu

2010-01-01

403

PREDICTING ACHIEVEMENT FOR DEAF CHILDREN.  

ERIC Educational Resources Information Center

THIS STUDY WAS DONE TO DETERMINE THE PREDICTIVE VALUE OF INDIVIDUAL AND GROUP ACHIEVEMENT TESTS WHEN USED TO EVALUATE DEAF CHILDREN. THE 36 CHILDREN SELECTED FOR THIS STUDY WERE IN GRADES 2, 4, AND 6 IN THE KENNEDY SCHOOL IN DAYTON, OHIO. ALL HAD SEVERE AUDITORY HANDICAPS AND WERE 10 TO 16 YEARS OLD. FOUR PSYCHOLOGISTS ADMINISTERED THE FOLLOWING…

BONHAM, S.J., JR.

404

UNIVERSITY ACHIEVEMENT AND DAYDREAMING BEHAVIOR  

Microsoft Academic Search

AN INVERSE ASSOCIATION WAS HYPOTHESIZED BETWEEN ACADEMIC ACHIEVEMENT LEVEL AND FREQUENCY OF DAYDREAMING ACTIVITY. UNDERGRADUATE WOMEN (101) AND MEN (105) RESPONDED TO A DAYDREAMING ACTIVITY INSTRUMENT WHICH REQUIRED SS TO INDICATE ON A 5-POINT SCALE HOW FREQUENTLY THEY HAD HAD EACH OF 120 COMMON DAYDREAM ITEMS. THE HYPOTHESIS WAS SUPPORTED (FOR WOMEN, BUT NOT FOR MEN) BY THE FINDINGS OF

MORTON WAGMAN

1968-01-01

405

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

406

Measuring and Recording Student Achievement  

ERIC Educational Resources Information Center

The Measuring and Recording Student Achievement Scoping Group was established by Universities UK and the Standing Conference of Principals (SCOP), with the support of the Higher Education Funding Council for England (HEFCE) in October 2003 to review the recommendations from the UK Government White Paper "The Future of Higher Education" relating…

Universities UK, 2004

2004-01-01

407

Believing and Achieving. Issue Brief  

ERIC Educational Resources Information Center

This research brief takes a look at the role of teacher efficacy-how teachers' beliefs in their own abilities affect student achievement. The brief examines the influence of perceived efficacy and building teacher confidence (social persuasion, collegiality, and shared decision making). It concludes by asserting that more positive steps must be…

Jerald, Craig D.

2007-01-01

408

Maximizing Student Achievement through Testing.  

ERIC Educational Resources Information Center

The present research attempted to determine if tests can serve as teaching devices by comparing student achievement in classes where several examinations were administered. Students in ten classes of introductory psychology served as subjects in the study. Three classes received weekly, teacher-made quizzes of 15 multiple-choice items; four…

Wilkins, S. A.

409

Goal Setting to Achieve Results  

ERIC Educational Resources Information Center

Both districts and individual schools have a very clear set of goals and skills for their students to achieve and master. In fact, except in rare cases, districts and schools develop very detailed goals they wish to pursue. In most cases, unfortunately, only the teachers and staff at a particular school or district-level office are aware of the…

Newman, Rich

2012-01-01

410

Helping Rural Schools Achieve Success.  

ERIC Educational Resources Information Center

Senator Collins of Maine plans to fight for proper federal funding of the Rural Education Achievement Program (REAP) that allows rural schools to combine federal funding sources. Collins, and Senator Dianne Feinstein, will soon introduce legislation that will eliminate inequities in the current Social Security law that penalize teachers and other…

Collins, Susan

2003-01-01

411

Family Composition and Mathematics Achievement.  

ERIC Educational Resources Information Center

Significant differences were found in the mathematics test scores and word knowledge scores of Swedish junior high school students from one-parent versus two-parent families. Similar lower achievement patterns for students from one-parent families emerged with high school seniors. Results are discussed in terms of family configuration theories.…

McNab, Christine; Murray, Asa

1985-01-01

412

Washington State's Student Achievement Initiative  

ERIC Educational Resources Information Center

This article describes Washington State's Student Achievement Initiative, an accountability system implemented in 2005-06 that measures students' gains in college readiness, college credits earned, and degree or certificate completion. The goal of the initiative is to increase educational attainment by focusing on the critical momentum points…

Pettitt, Maureen; Prince, David

2010-01-01

413

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

414

Word Study and Spelling Achievement.  

ERIC Educational Resources Information Center

An action research project was conducted to measure any difference in spelling achievement after Word Study activities were used during spelling instruction. Word Study approaches to spelling instruction offer hands-on experiences with the manipulation of letters to form words. It was hypothesized that students taught spelling skills with a Word…

Brandt, Tiffany E.; Gielbelhaus, Carmen R.

415

Teachers, Schools, and Academic Achievement  

Microsoft Academic Search

This paper disentangles the impact of schools and teachers in influencing achievement with special attention given to the potential problems of omitted or mismeasured variables and of student and school selection. Unique matched panel data from the UTD Texas Schools Project permit the identification of teacher quality based on student performance along with the impact of specific, measured components of

Steven G. Rivkin; Eric A. Hanushek; John F. Kain

2005-01-01

416

Achieving high Curie temperature in (Ga,Mn)As  

Microsoft Academic Search

We study the effects of growth temperature, Ga:As ratio, and postgrowth annealing procedure on the Curie temperature TC of (Ga,Mn)As layers grown by molecular beam epitaxy. We achieve the highest TC values for growth temperatures very close to the two-dimensional-three-dimensional phase boundary. The increase in TC, due to the removal of interstitial Mn by postgrowth annealing, is counteracted by a

M. Wang; R. P. Campion; A. W. Rushforth; K. W. Edmonds; C. T. Foxon; B. L. Gallagher

2008-01-01

417

Achieving high Curie temperature in (Ga,Mn)As  

Microsoft Academic Search

We study the effects of growth temperature, Ga:As ratio, and postgrowth annealing procedure on the Curie temperature TC of (Ga,Mn)As layers grown by molecular beam epitaxy. We achieve the highest TC values for growth temperatures very close to the two-dimensional–three-dimensional phase boundary. The increase in TC, due to the removal of interstitial Mn by postgrowth annealing, is counteracted by a

M. Wang; R. P. Campion; A. W. Rushforth; K. W. Edmonds; C. T. Foxon; B. L. Gallagher

2008-01-01

418

Advances in growth of fiber crystal by the LHPG technique. Application to the optimization of Yb 3+-doped CaF 2 laser crystals  

NASA Astrophysics Data System (ADS)

The laser heated pedestal growth (LHPG) technique is suitable to grow crystalline fibers and has been successfully applied for the general study of a lot of optical materials as laser crystals. Our general approach on the research of diode-pumped Yb 3+-doped host crystals is presented through typical example of CaF 2 fluoride, which is considered among the important laser crystals either for basic or applied reasons. Spectroscopic characterizations were carried out. Especially, Yb 3+ ( 2F 5/2) excited level experimental decay time dependence on Yb 3+ ion concentration is analyzed by using our own approach on the synthesis of a concentration gradient fiber grown in the laboratory. Our main objective is to contribute to have a better understanding of concentration quenching mechanisms not only in laser crystals but more generally in luminescent materials.

Boulon, G.; Ito, M.; Goutaudier, C.; Guyot, Y.

2006-07-01

419

Achieved Energy Assessment and Modeling of Railway Transportation Systems with Three Levels Converters  

Microsoft Academic Search

This paper emphasizes a number of sustainability- based concepts, such achieved energy and exergy efficiency, related as tools in order to describe, analyse and optimize energy conversion in electric railway transportation systems. For the sustainable railway vehicles, the achieved energy assessment provides a basis for exergy efficiency increasing, reducing both energy losses and environmental damage. Further on, achieved energy and

Daniel C. Cismaru; Doru A. Nicola; Cornelia A. Bulucea; Gheorghe Manole; Gabriela M. Cismaru

2008-01-01

420

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

421

Optimal disturbances in parallel shear flows  

Microsoft Academic Search

In this work we investigate the growth of optimal disturbances in parallel shear flows. First we re-examine the known results for circular pipe flow. Optimal disturbances are found for spatial and temporal stability analysis. It is found for both cases that the initial disturbance, which yields maximum transient growth, has a similar character. It is further shown that in both

Guy Ben-Dov; Vladimir Levinski; Jacob Cohen

2002-01-01

422

Optimizing Locomotion  

NASA Astrophysics Data System (ADS)

In this talk we will discuss two optimization topics related to low Reynolds number locomotion: optimal stroke patterns in linked swimmers and optimal fluid material properties in adhesive locomotion. In contrast to many optimization problems, we do not consider geometry, rather we optimize the swimming kinematics or fluid material properties for a given geometrical configuration. In the first case, we begin by optimizing stroke patterns for Purcell's 3-link swimmer. We model the swimmer as a jointed chain of three slender links moving in an inertialess flow. The swimmer is optimized for both efficiency and speed. In the second case, we analyze the adhesive locomotion used by common gastropods such as snails and slugs. Such organisms crawl on a solid substrate by propagating muscular waves of shear stress on a viscoelastic mucus. Using a simple mechanical model, we derive criteria for favorable fluid material properties to lower the energetic cost of locomotion.

Hosoi, Anette

2006-11-01

423

Asperger Syndrome and Academic Achievement  

Microsoft Academic Search

This study focused on identifying the academic characteristics of children and youth Who have Asperger syndrome (AS). Significant numbers of school-age children have AS, yet little is knoWn about the unique educational features of individuals With this pervasive developmental disorder. TWenty-one children and youth With diagnoses of AS Were assessed using the Wechsler Individual Achievement Test (WIAT; Psychological Corp., 1992),

Deborah E. Griswold; Gena P. Barnhill; Brenda Smith Myles; Taku Hagiwara; Richard L. Simpson

2002-01-01

424

Mathematics, Engineering, Science Achievement (MESA)  

NSDL National Science Digital Library

California's Mathematics, Engineering, Science Achievement (MESA), founded in 1970, assists students to become highly trained technological professionals by serving educationally disadvantaged students and, to the extent possible by law, emphasizes participation by students from groups with low eligibility rates for four-year colleges. Learn about MESA initiatives such as its Schools Program (MSP), Success Through Collaboration (MESA STC), California Community College Program (CCCP), and Engineering Program (MEP).

2007-09-05

425

School Readiness and Later Achievement  

Microsoft Academic Search

Using 6 longitudinal data sets, the authors estimate links between three key elements of school readiness—school-entry academic, attention, and socioemotional skills—and later school reading and math achievement. In an effort to isolate the effects of these school-entry skills, the authors ensured that most of their regression models control for cognitive, attention, and socioemotional skills measured prior to school entry, as

Greg J. Duncan; Chantelle J. Dowsett; Amy Claessens; Katherine Magnuson; Aletha C. Huston; Pamela Klebanov; Linda S. Pagani; Leon Feinstein; Mimi Engel; Jeanne Brooks-Gunn; Holly Sexton; Kathryn Duckworth; Crista Japel

2007-01-01

426

Optimizations and oracle parallelism with dynamic translation  

Microsoft Academic Search

We describe several optimizations which can be employed in a dynamic binary translation (DBT) system, where low compilation\\/translation overhead is essential. These optimizations achieve a high degree of ILP, sometimes even surpassing a static compiler employing more sophisticated, and more time-consuming algorithms [9]. We present results in which we employ these optimizations in a dynamic binary translation system capable of

Kemal Ebcio?lu; Erik R. Altman; Michael Gschwind; Sumedh Sathaye

1999-01-01

427

On the optimizing-adaptive control problem  

Microsoft Academic Search

The optimizing-adaptive control problem arises in applications where the desired behavior is not specified explicitly, but instead, an objective function of the plant behavior and the unknown plant itself is to be optimized. In these cases, the control task involves the explicit determination of the optimal behavior and the control action to achieve that behavior. The difficulty with this problem

Perry Y. Li; Roberto Horowitz

1994-01-01

428

A Cooperative Approach to Particle Swarm Optimization  

Microsoft Academic Search

The particle swarm optimizer (PSO) is a stochastic, population-based optimization technique that can be applied to a wide range of problems, including neural network training. This paper presents a variation on the traditional PSO algorithm, called the cooperative particle swarm optimizer, or CPSO, employing cooperative behavior to significantly improve the performance of the original algorithm. This is achieved by using

F. Vandenbergh; Andries Petrus Engelbrecht

2004-01-01

429

Optimal sensor configuration for complex systems  

Microsoft Academic Search

The paper considers the problem of sensor configuration for complex systems with the aim of maximizing the useful information about certain quantities of interest. Our approach involves: 1) definition of an appropriate optimality criterion or performance measure; and 2) description of an efficient and practical algorithm for achieving the optimality objective. The criterion for optimal sensor configuration is based on

PAYMAN SADEGH; J. C. Spall

1998-01-01

430

Identification and optimization of new dual inhibitors of B-Raf and epidermal growth factor receptor kinases for overcoming resistance against vemurafenib.  

PubMed

Epidermal growth factor receptor (EGFR) amplification has been demonstrated to be critical for the inherent and/or acquired resistance against current B-Raf(V600E) inhibitor therapy for melanoma and colorectal cancer patients. We describe the discovery and structure-activity relationship study of a series of 1H-pyrazolo[3,4-b]pyridine-5-carboxamide analogues as novel dual inhibitors of EGFR and B-Raf(V600E) mutant. One of the most promising compounds, 6a, potently inhibited both of the kinases with IC50 values of 8.0 and 51 nM, respectively. The compound also strongly suppressed the proliferation of a panel of intrinsic and acquired resistant melanoma and/or colorectal cancer cells harboring overexpressed EGFR with submicromolar IC50 values. Further mechanism investigation revealed that 6a could sustainably inhibit the activation of the MAPK path way in the resistant SK-MEL-28 PR30 melanoma cancer cells and WiDr colorectal cancer cells with EGFR amplification. Our results support the hypothesis that the EGFR/B-Raf(V600E) dual inhibition might be a tractable strategy to overcome the intrinsic and acquired resistance of melanoma and/or colorectal cancers against the current B-Raf(V600E) inhibitor therapy. PMID:24588073

Cheng, Huimin; Chang, Yu; Zhang, Lianwen; Luo, Jinfeng; Tu, Zhengchao; Lu, Xiaoyun; Zhang, Qingwen; Lu, Jibu; Ren, Xiaomei; Ding, Ke

2014-03-27

431

Optimization of 2-(3-(arylalkyl amino carbonyl) phenyl)-3-(2-methoxyphenyl)-4-thiazolidinone derivatives as potent antitumor growth and metastasis agents.  

PubMed

A series of 2,3-diaryl-4-thiazolidinone derivatives were synthesized and evaluated for their antiproliferative properties against two well-known cancer cell lines (A549 as human lung cancer and MDA-MB-231 as human breast cancer). Structure activity relationship (SAR) analysis resulted in the discovery of 2-(3-(arylalkyl amino carbonyl)phenyl)-3-(2-methoxy-phenyl)-4-thiazolidinone derivatives with high potent inhibitory effects on the proliferation of both cancer cell lines. Furthermore, several compounds with potent antiproliferative activities displayed excellent inhibitory activities on migration with an IC50 of about 0.05 ?M on MDA-MB-231 cells in two different migration assays. In particular, compound 39 was indicated to suppress tumor growth and metastasis as well as promote survival rate. Intriguingly, this series of analogs have been indicated to inhibit tumor cell proliferation through inducing cell cycle arrest. These results suggested that the new series of 2-(3-(arylalkyl amino carbonyl)phenyl)-3-(2-methoxyphenyl)-4-thiazolidinone derivatives could be regarded and developed as novel highly potential anticancer agents in the future. PMID:24794770

Wu, Jing; Yu, Linxi; Yang, Feifei; Li, Jingjie; Wang, Peng; Zhou, Wenbo; Qin, Liwen; Li, Yunqi; Luo, Jian; Yi, Zhengfang; Liu, Mingyao; Chen, Yihua

2014-06-10

432

Future Directions: Growth Prediction Models  

Microsoft Academic Search

Background: One strategy for optimizing growth hormone (GH) treatment is to develop mathematical models based on clinical data from the large numbers of subjects in the KIGS (Pfizer International Growth Study Database) and to compare the observed versus predicted growth responses in subjects with short stature secondary to idiopathic GH deficiency (GHD), Turner syndrome, small birth size and idiopathic causes

Mitchell E. Geffner; David B. Dunger

2007-01-01

433

Classroom Order and Student Learning in Late Elementary School: A Multilevel Transactional Model of Achievement Trajectories  

ERIC Educational Resources Information Center

This study examines the association between classroom order in 4th and 5th grades and student achievement growth over a school year. A three level transactional model tested the effects of classroom order on students' rates of growth in math and reading during the school year controlling for starting achievement levels, student risk factors, and…

Gaskins, Clare S.; Herres, Joanna; Kobak, Roger

2012-01-01

434

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

435

Export of vacuolar manganese by AtNRAMP3 and AtNRAMP4 is required for optimal photosynthesis and growth under manganese deficiency.  

PubMed

Manganese (Mn) is an essential element, acting as cofactor in numerous enzymes. In particular, a Mn cluster is indispensable for the function of the oxygen-evolving complex of photosystem II. Metal transporters of the Natural Resistance-Associated Macrophage Protein (NRAMP) family have the ability to transport both iron and Mn. AtNRAMP3 and AtNRAMP4 are required for iron mobilization in germinating seeds. The results reported here show that, in adult Arabidopsis (Arabidopsis thaliana) plants, AtNRAMP3 and AtNRAMP4 have an important role in Mn homeostasis. Vacuolar Mn accumulation in mesophyll cells of rosette leaves of adult nramp3nramp4 double mutant plants was dramatically increased when compared with the wild type. This suggests that a considerable proportion of the cellular Mn pool passes through the vacuole and is retrieved in an AtNRAMP3/AtNRAMP4-dependent manner. The impaired Mn release from mesophyll vacuoles of nramp3nramp4 double mutant plants is associated with reduced growth under Mn deficiency. However, leaf AtNRAMP3 and AtNRAMP4 protein levels are unaffected by Mn supply. Under Mn deficiency, nramp3nramp4 plants contain less functional photosystem II than the wild type. These data are consistent with a shortage of Mn to produce functional photosystem II, whereas mitochondrial Mn-dependent superoxide dismutase activity is maintained under Mn deficiency in both genotypes. The results presented here suggest an important role for AtNRAMP3/AtNRAMP4-dependent Mn transit through the vacuole prior to the import into chloroplasts of mesophyll cells. PMID:20181755

Lanquar, Viviane; Ramos, Magali Schnell; Lelièvre, Françoise; Barbier-Brygoo, Hélène; Krieger-Liszkay, Anja; Krämer, Ute; Thomine, Sébastien

2010-04-01

436

Export of Vacuolar Manganese by AtNRAMP3 and AtNRAMP4 Is Required for Optimal Photosynthesis and Growth under Manganese Deficiency1[W  

PubMed Central

Manganese (Mn) is an essential element, acting as cofactor in numerous enzymes. In particular, a Mn cluster is indispensable for the function of the oxygen-evolving complex of photosystem II. Metal transporters of the Natural Resistance-Associated Macrophage Protein (NRAMP) family have the ability to transport both iron and Mn. AtNRAMP3 and AtNRAMP4 are required for iron mobilization in germinating seeds. The results reported here show that, in adult Arabidopsis (Arabidopsis thaliana) plants, AtNRAMP3 and AtNRAMP4 have an important role in Mn homeostasis. Vacuolar Mn accumulation in mesophyll cells of rosette leaves of adult nramp3nramp4 double mutant plants was dramatically increased when compared with the wild type. This suggests that a considerable proportion of the cellular Mn pool passes through the vacuole and is retrieved in an AtNRAMP3/AtNRAMP4-dependent manner. The impaired Mn release from mesophyll vacuoles of nramp3nramp4 double mutant plants is associated with reduced growth under Mn deficiency. However, leaf AtNRAMP3 and AtNRAMP4 protein levels are unaffected by Mn supply. Under Mn deficiency, nramp3nramp4 plants contain less functional photosystem II than the wild type. These data are consistent with a shortage of Mn to produce functional photosystem II, whereas mitochondrial Mn-dependent superoxide dismutase activity is maintained under Mn deficiency in both genotypes. The results presented here suggest an important role for AtNRAMP3/AtNRAMP4-dependent Mn transit through the vacuole prior to the import into chloroplasts of mesophyll cells.

Lanquar, Viviane; Ramos, Magali Schnell; Lelievre, Francoise; Barbier-Brygoo, Helene; Krieger-Liszkay, Anja; Kramer, Ute; Thomine, Sebastien

2010-01-01

437

Achieving low-carbon economy by disruptive innovation in China  

Microsoft Academic Search

This paper proposes a framework for China to achieve low-carbon economy by disruptive innovations. Chinapsilas rapid industrialization and economic growth have significantly increased its energy consumption. The issue of Greenhouse Gas mitigation poses a huge challenge to China to create an innovative and sustainable development pattern. Both theoretical and empirical studies imply that technological transition approach would be a suitable

Zhiwei Wang; Jin Chen

2008-01-01

438

The Impact of Ready Environments on Achievement in Kindergarten  

ERIC Educational Resources Information Center

The purpose of this study was to examine how young children's homes and preschool programs influence kindergarten achievement by being "ready environments." Ready environments provide opportunities for cognitive and social growth through culturally and developmentally appropriate activities, interactions, and materials. This study used…

Nelson, Regena Fails

2005-01-01

439

Recent Achievements in Hypernuclear Physics  

NASA Astrophysics Data System (ADS)

In the last decade the hypernuclear physics community was committed to carrying on several third-generation experiments. Large data samples were collected on specific items, thanks to dedicated facilities and experimental apparatuses. The attention was focused on both high-resolution spectroscopy and decay mode study of single ?-hypernuclei. Nowadays this phase is over but, until recently, important and to some extent unexpected results were achieved. Among others, the claim for the first observation of the neutron-rich hypernucleus {^6_?H} and the first experimental evidence for the hypernucleus two-nucleon induced weak decay raised strong interest.

Feliciello, Alessandro

2013-12-01

440

Optimization Online  

NSDL National Science Digital Library

Optimization Online is one of the best sources for current research papers and reports on the topic of optimization. This repository receives numerous submissions each month, and papers can be browsed by data added or category. In addition to searching for articles on the site, visitors can also subscribe to the Optimization Online monthly digest and receive updates on all of the new titles and reports submitted during that month.

2008-05-19

441

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