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Sample records for achieving optimal growth

  1. Achieving optimal growth: lessons from simple metabolic modules

    NASA Astrophysics Data System (ADS)

    Goyal, Sidhartha; Chen, Thomas; Wingreen, Ned

    2009-03-01

    Metabolism is a universal property of living organisms. While the metabolic network itself has been well characterized, the logic of its regulation remains largely mysterious. Recent work has shown that growth rates of microorganisms, including the bacterium Escherichia coli, correlate well with optimal growth rates predicted by flux-balance analysis (FBA), a constraint-based computational method. How difficult is it for cells to achieve optimal growth? Our analysis of representative metabolic modules drawn from real metabolism shows that, in all cases, simple feedback inhibition allows nearly optimal growth. Indeed, product-feedback inhibition is found in every biosynthetic pathway and constitutes about 80% of metabolic regulation. However, we find that product-feedback systems designed to approach optimal growth necessarily produce large pool sizes of metabolites, with potentially detrimental effects on cells via toxicity and osmotic imbalance. Interestingly, the sizes of metabolite pools can be strongly restricted if the feedback inhibition is ultrasensitive (i.e. with high Hill coefficient). The need for ultrasensitive mechanisms to limit pool sizes may therefore explain some of the ubiquitous, puzzling complexity found in metabolic feedback regulation at both the transcriptional and post-transcriptional levels.

  2. Isometric Scaling in Developing Long Bones Is Achieved by an Optimal Epiphyseal Growth Balance.

    PubMed

    Stern, Tomer; Aviram, Rona; Rot, Chagai; Galili, Tal; Sharir, Amnon; Kalish Achrai, Noga; Keller, Yosi; Shahar, Ron; Zelzer, Elazar

    2015-08-01

    One of the major challenges that developing organs face is scaling, that is, the adjustment of physical proportions during the massive increase in size. Although organ scaling is fundamental for development and function, little is known about the mechanisms that regulate it. Bone superstructures are projections that typically serve for tendon and ligament insertion or articulation and, therefore, their position along the bone is crucial for musculoskeletal functionality. As bones are rigid structures that elongate only from their ends, it is unclear how superstructure positions are regulated during growth to end up in the right locations. Here, we document the process of longitudinal scaling in developing mouse long bones and uncover the mechanism that regulates it. To that end, we performed a computational analysis of hundreds of three-dimensional micro-CT images, using a newly developed method for recovering the morphogenetic sequence of developing bones. Strikingly, analysis revealed that the relative position of all superstructures along the bone is highly preserved during more than a 5-fold increase in length, indicating isometric scaling. It has been suggested that during development, bone superstructures are continuously reconstructed and relocated along the shaft, a process known as drift. Surprisingly, our results showed that most superstructures did not drift at all. Instead, we identified a novel mechanism for bone scaling, whereby each bone exhibits a specific and unique balance between proximal and distal growth rates, which accurately maintains the relative position of its superstructures. Moreover, we show mathematically that this mechanism minimizes the cumulative drift of all superstructures, thereby optimizing the scaling process. Our study reveals a general mechanism for the scaling of developing bones. More broadly, these findings suggest an evolutionary mechanism that facilitates variability in bone morphology by controlling the activity of individual epiphyseal plates. PMID:26241802

  3. Isometric Scaling in Developing Long Bones Is Achieved by an Optimal Epiphyseal Growth Balance

    PubMed Central

    Stern, Tomer; Aviram, Rona; Rot, Chagai; Galili, Tal; Sharir, Amnon; Kalish Achrai, Noga; Keller, Yosi; Shahar, Ron; Zelzer, Elazar

    2015-01-01

    One of the major challenges that developing organs face is scaling, that is, the adjustment of physical proportions during the massive increase in size. Although organ scaling is fundamental for development and function, little is known about the mechanisms that regulate it. Bone superstructures are projections that typically serve for tendon and ligament insertion or articulation and, therefore, their position along the bone is crucial for musculoskeletal functionality. As bones are rigid structures that elongate only from their ends, it is unclear how superstructure positions are regulated during growth to end up in the right locations. Here, we document the process of longitudinal scaling in developing mouse long bones and uncover the mechanism that regulates it. To that end, we performed a computational analysis of hundreds of three-dimensional micro-CT images, using a newly developed method for recovering the morphogenetic sequence of developing bones. Strikingly, analysis revealed that the relative position of all superstructures along the bone is highly preserved during more than a 5-fold increase in length, indicating isometric scaling. It has been suggested that during development, bone superstructures are continuously reconstructed and relocated along the shaft, a process known as drift. Surprisingly, our results showed that most superstructures did not drift at all. Instead, we identified a novel mechanism for bone scaling, whereby each bone exhibits a specific and unique balance between proximal and distal growth rates, which accurately maintains the relative position of its superstructures. Moreover, we show mathematically that this mechanism minimizes the cumulative drift of all superstructures, thereby optimizing the scaling process. Our study reveals a general mechanism for the scaling of developing bones. More broadly, these findings suggest an evolutionary mechanism that facilitates variability in bone morphology by controlling the activity of individual epiphyseal plates. PMID:26241802

  4. Systems' optimization: Achieving the balance

    NASA Astrophysics Data System (ADS)

    Kraus, Peter

    1994-04-01

    Fuel cells for stationary power generation applications are being pursued on a large scale worldwide in an effort to achieve commercialization before the turn of the century. Some aspects of system optimization are discussed illustrating the influence of basic system design possibilities. Design variants investigated include alternatives for anode and cathode gas supply and gas recycling, methods to achieve self-sufficiency on water for the reforming of natural gas, and recovery of unspent fuel from the anode exhaust. Especially in small systems for decentralized applications, e.g., industrial cogeneration, system simplification is decisive to bring down the capital cost of the balance-of-plant. Trade-offs between system complexity and efficiency are possible to optimize the economy. In large plants, high-temperature fuel cell can be supplemented with bottoming cycles for best fuel utilization. Gas turbines and steam turbines can be evaluated, having strong influence on the system design pressures and, therefore, system cost.

  5. Optimism versus Pessimism and Academic Achievement Evaluation

    ERIC Educational Resources Information Center

    Harpaz-Itay, Yifat; Kaniel, Shlomo

    2012-01-01

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

  6. The Growth Patterns of General Medical Achievement.

    ERIC Educational Resources Information Center

    Shen, Linjun

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

  7. Student Achievement and National Economic Growth

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  8. Mathematics Coursework Regulates Growth in Mathematics Achievement

    ERIC Educational Resources Information Center

    Ma, Xin; Wilkins, Jesse L. M.

    2007-01-01

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

  9. Optimization of microorganisms growth processes.

    PubMed

    Sbarciog, M; Loccufier, M; Noldus, E

    2011-11-01

    Microorganisms growth processes are encountered in many biotechnological applications. For an increased economic benefit, optimizing their productivity is of great interest. Often the growth is inhibited by the presence in excess of other components. Inhibition determines the occurrence of multiple equilibrium points, which makes the optimal steady state reachable only from a small region of the system state space. Thus dynamic control is needed to drive the system from an initial state (characterized by a low concentration of microorganisms) to the optimal steady state. The strategy presented in this paper relies on the solutions of two optimization problems: the problem of optimal operation for maximum productivity in steady state (steady state optimization) and the problem of the start-up to the optimal steady state (transient optimization). Steady state optimization means determining the optimal equilibrium point (the amount of microorganisms harvested is maximum). The transient optimization is solved using the maximum principle of Pontryagin. The proposed control law, which drives the bioreactor from an initial state to the optimal steady state while maximizing the productivity, consists of switching the manipulated variable (dilution rate) from the minimum to the maximum value and then to the optimal value at well defined instants. This control law substantially increases the stability region of the optimal equilibrium point. Aside its efficiency, the strategy is also characterized by simplicity, being thus appropriate for implementation in real-life systems. Another important advantage is its generality: this technique may be applied to any microorganisms growth process which involves only one biochemical reaction. This means that the sequence of the control levels does not depend on the structure and parameters of the reaction kinetics, the values of the yield coefficients or the number of components in the bioreactor. PMID:20615574

  10. Optimal energy growth in swept Hiemenz flow

    NASA Astrophysics Data System (ADS)

    Guegan, Alan; Huerre, Patrick; Schmid, Peter

    2006-11-01

    It has been shown in Gu'egan, Schmid & Huerre 2006 that the kinetic energy of optimal G"ortler-H"ammerlin (GH) perturbations in swept Hiemenz flow can be transiently amplified by two orders of magnitude at Reynolds numbers ranging from 400 to 1000 and spanwise wavenumbers from 0.1 to 0.5. In this configuration an array of counter-rotating chordwise vortices is compressed by the spanwise shear, as in the well-known Orr mechanism. We show that stronger transient growth can be achieved when the GH assumption is relaxed. In this case the optimal initial perturbation consists in vorticity sheets stacked in the chordwise direction, at a small angle from the symmetry plane of the base flow. Although the spatial structure of the GH perturbations is lost, wall-normal-spanwise plane cuts show that the amplification mechanism is mostly unchanged. The GH assumption thus provides a reasonably good estimate for transient energy amplification levels in swept Hiemenz flow. Extension of this analysis to the spatial growth problem is under way and preliminary results will be shown.

  11. The Effects of Academic Optimism on Elementary Reading Achievement

    ERIC Educational Resources Information Center

    Bevel, Raymona K.; Mitchell, Roxanne M.

    2012-01-01

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

  12. Optimal consumption models in economic growth

    NASA Astrophysics Data System (ADS)

    Morimoto, Hiroaki

    2008-01-01

    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.

  13. Documenting Reading Achievement and Growth for Students Taking Alternate Assessments

    ERIC Educational Resources Information Center

    Tindal, Gerald; Nese, Joseph F. T.; Farley, Dan; Saven, Jessica L.; Elliott, Stephen N.

    2016-01-01

    Students with disabilities have been included in state accountability systems for more than a decade; however, only in the past few years have alternate assessments of alternate achievement standards (AA-AAS) become stable enough to allow examination of these students' achievement growth. Using data from Oregon's AA-AAS in Reading during the…

  14. The Role of Academic Achievement Growth in School Track Recommendations

    ERIC Educational Resources Information Center

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

    2009-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Johnson, Ursula Yvette

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

  16. Optimal growth strategies under divergent predation pressure.

    PubMed

    Aikio, S; Herczeg, G; Kuparinen, A; Meril, J

    2013-01-01

    The conditions leading to gigantism in nine-spined sticklebacks Pungitius pungitius were analysed by modelling fish growth with the von Bertalanffy model searching for the optimal strategy when the model's growth constant and asymptotic fish size parameters are negatively related to each other. Predator-related mortality was modelled through the increased risk of death during active foraging. The model was parameterized with empirical growth data of fish from four different populations and analysed for optimal growth strategy at different mortality levels. The growth constant and asymptotic fish size were negatively related in most populations. Optimal fish size, fitness and life span decreased with predator-induced mortality. At low mortality, the fitness of pond populations was higher than that of sea populations. The differences disappeared at intermediate mortalities, and sea populations had slightly higher fitness at extremely high mortalities. In the scenario where all populations mature at the same age, the pond populations perform better at low mortalities and the sea populations at high mortalities. It is concluded that a trade-off between growth constant and asymptotic fish size, together with different mortality rates, can explain a significant proportion of body size differentiation between populations. In the present case, it is a sufficient explanation of gigantism in pond P. pungitius. PMID:23331153

  17. Postinfancy growth, schooling, and cognitive achievement: Young Lives1234

    PubMed Central

    Schott, Whitney; Cueto, Santiago; Dearden, Kirk A; Engle, Patrice; Georgiadis, Andreas; Lundeen, Elizabeth A; Penny, Mary E; Stein, Aryeh D; Behrman, Jere R

    2013-01-01

    Background: Early life growth failure and resulting cognitive deficits are often assumed to be very difficult to reverse after infancy. Objective: We used data from Young Lives, which is an observational cohort of 8062 children in Ethiopia, India, Peru, and Vietnam, to determine whether changes in growth after infancy are associated with schooling and cognitive achievement at age 8 y. Design: We represented the growth by height-for-age z score at 1 y [HAZ(1)] and height-for-age z score at 8 y that was not predicted by the HAZ(1). We also characterized growth as recovered (stunted at age 1 y and not at age 8 y), faltered (not stunted at age 1 y and stunted at age 8 y), persistently stunted (stunted at ages 1 and 8 y), or never stunted (not stunted at ages 1 and 8 y). Outcome measures were assessed at age 8 y. Results: The HAZ(1) was inversely associated with overage for grade and positively associated with mathematics achievement, reading comprehension, and receptive vocabulary. Unpredicted growth from 1 to 8 y of age was also inversely associated with overage for grade (OR range across countries: 0.80–0.84) and positively associated with mathematics achievement (effect-size range: 0.05–0.10), reading comprehension (0.02–0.10), and receptive vocabulary (0.04–0.08). Children who recovered in linear growth had better outcomes than did children who were persistently stunted but were not generally different from children who experienced growth faltering. Conclusions: Improvements in child growth after early faltering might have significant benefits on schooling and cognitive achievement. Hence, although early interventions remain critical, interventions to improve the nutrition of preprimary and early primary school–age children also merit consideration. PMID:24067665

  18. Effects of Teacher Professional Learning Activities on Student Achievement Growth

    ERIC Educational Resources Information Center

    Akiba, Motoko; Liang, Guodong

    2016-01-01

    The authors examined the effects of six types of teacher professional learning activities on student achievement growth over 4 years using statewide longitudinal survey data collected from 467 middle school mathematics teachers in 91 schools merged with 11,192 middle school students' mathematics scores in a standardized assessment in Missouri. The…

  19. Optimized Delivery System Achieves Enhanced Endomyocardial Stem Cell Retention

    PubMed Central

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

    2014-01-01

    Background Regenerative cell-based therapies are associated with limited myocardial retention of delivered stem cells. The objective of this study is to develop an endocardial delivery system for enhanced cell retention. Methods and Results Stem cell retention was simulated in silico using one and three-dimensional models of tissue distortion and compliance associated with delivery. Needle designs, predicted to be optimal, were accordingly engineered using nitinol a nickel and titanium alloy displaying shape memory and super-elasticity. Biocompatibility was tested with human mesenchymal stem cells. Experimental validation was performed with species-matched cells directly delivered into Langendorff-perfused porcine hearts or administered percutaneously into the endocardium of infarcted pigs. Cell retention was quantified by flow cytometry and real time quantitative polymerase chain reaction methodology. Models, computing optimal distribution of distortion calibrated to favor tissue compliance, predicted that a 75-curved needle featuring small-to-large graded side holes would ensure the highest cell retention profile. In isolated hearts, the nitinol curved needle catheter (C-Cath) design ensured 3-fold superior stem cell retention compared to a standard needle. In the setting of chronic infarction, percutaneous delivery of stem cells with C-Cath yielded a 37.77.1% versus 10.02.8% retention achieved with a traditional needle, without impact on biocompatibility or safety. Conclusions Modeling guided development of a nitinol-based curved needle delivery system with incremental side holes achieved enhanced myocardial stem cell retention. PMID:24326777

  20. Translational Geroscience: Emphasizing function to achieve optimal longevity

    PubMed Central

    Seals, Douglas R.; Melov, Simon

    2014-01-01

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

  1. Adaptation to optimal cell growth through self-organized criticality.

    PubMed

    Furusawa, Chikara; Kaneko, Kunihiko

    2012-05-18

    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

  2. Optimal achieved blood pressure in acute intracerebral hemorrhage

    PubMed Central

    Arima, Hisatomi; Heeley, Emma; Delcourt, Candice; Hirakawa, Yoichiro; Wang, Xia; Woodward, Mark; Robinson, Thompson; Stapf, Christian; Parsons, Mark; Lavados, Pablo M.; Huang, Yining; Wang, Jiguang; Chalmers, John

    2015-01-01

    Objectives: To investigate the effects of intensive blood pressure (BP) lowering according to baseline BP levels and optimal achieved BP levels in patients with acute intracerebral hemorrhage (ICH). Methods: INTERACT2 was an open, blinded endpoint, randomized controlled trial in 2,839 patients with ICH within 6 hours of onset and elevated systolic BP (SBP) (150–220 mm Hg) who were allocated to receive intensive (target SBP <140 mm Hg within 1 hour, with lower limit of 130 mm Hg for treatment cessation) or guideline-recommended (target SBP <180 mm Hg) BP-lowering treatment. Outcome was physical function across all 7 levels of the modified Rankin Scale at 90 days. Results: Analysis of the randomized comparisons showed that intensive BP lowering produced comparable benefits on physical function at 90 days in 5 subgroups defined by baseline SBP of <160, 160–169, 170–179, 180–189, and ≥190 mm Hg (p homogeneity = 0.790). Analyses of achieved BP showed linear increases in the risk of physical dysfunction for achieved SBP above 130 mm Hg for both hyperacute (1–24 hours) and acute (2–7 days) phases while modest increases were also observed for achieved SBP below 130 mm Hg. Conclusions: Intensive BP lowering appears beneficial across a wide range of baseline SBP levels, and target SBP level of 130–139 mm Hg is likely to provide maximum benefit in acute ICH. Classification of evidence: This study provides Class I evidence that the effect of intensive BP lowering on physical function is not influenced by baseline BP. PMID:25552575

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

    PubMed

    Skinner, Mark W

    2012-07-01

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

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

    PubMed Central

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

    2013-01-01

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

  5. Graphene growth on SiC(000-1): optimization of surface preparation and growth conditions

    NASA Astrophysics Data System (ADS)

    Robinson, Zachary R.; Jernigan, Glenn G.; Bussmann, Konrad M.; Nyakiti, Luke O.; Garces, Nelson Y.; Nath, Anindya; Wheeler, Virginia D.; Myers-Ward, Rachael L.; Gaskill, D. K.; Eddy, Charles R.

    2015-09-01

    Graphene growth of high crystal quality and single-layer thickness can be achieved by low pressure sublimation (LPS) on SiC(0001). On SiC(0001), which is the C-terminated polar surface, there has been much less success growing uniform, single-layer films. In this work, a systematic study of surface preparation by hydrogen etching followed by LPS in an argon ambient was performed. Hydrogen etching is an important first step in the graphene growth process because it removes damage caused by polishing the substrate surface. However, for SiC(0001), etching at too high of a temperature or for too long has been found to result in pit formation due to the preferential etching of screw dislocations that intersect the surface. It was found that temperatures above 1450°C in 200mbar of hydrogen result in pitting of the surface, whereas etch temperatures at and below 1450°C can result in atomically at terraces of ~ 1 µm width. Following the hydrogen etch optimization, argon-mediated graphene growth was carried out at several different temperatures. For the growth experiments, pressure and growth time were both fixed. Regardless of growth temperature, all of the films were found to have non-uniform thickness. Further, x-ray photoelectron spectroscopy and low energy electron diffraction measurements reveal that trace amounts of oxygen, which may be present during growth, significantly affects the graphene growth process on this polar surface.

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  8. Functional and Structural Optimality in Plant Growth: A Crop Modelling Case Study

    NASA Astrophysics Data System (ADS)

    Caldararu, S.; Purves, D. W.; Smith, M. J.

    2014-12-01

    Simple mechanistic models of vegetation processes are essential both to our understanding of plant behaviour and to our ability to predict future changes in vegetation. One concept that can take us closer to such models is that of plant optimality, the hypothesis that plants aim to achieve an optimal state. Conceptually, plant optimality can be either structural or functional optimality. A structural constraint would mean that plants aim to achieve a certain structural characteristic such as an allometric relationship or nutrient content that allows optimal function. A functional condition refers to plants achieving optimal functionality, in most cases by maximising carbon gain. Functional optimality conditions are applied on shorter time scales and lead to higher plasticity, making plants more adaptable to changes in their environment. In contrast, structural constraints are optimal given the specific environmental conditions that plants are adapted to and offer less flexibility. We exemplify these concepts using a simple model of crop growth. The model represents annual cycles of growth from sowing date to harvest, including both vegetative and reproductive growth and phenology. Structural constraints to growth are represented as an optimal C:N ratio in all plant organs, which drives allocation throughout the vegetative growing stage. Reproductive phenology - i.e. the onset of flowering and grain filling - is determined by a functional optimality condition in the form of maximising final seed mass, so that vegetative growth stops when the plant reaches maximum nitrogen or carbon uptake. We investigate the plants' response to variations in environmental conditions within these two optimality constraints and show that final yield is most affected by changes during vegetative growth which affect the structural constraint.

  9. Optimization of lamp spectrum for vegetable growth

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  10. Aircraft optimization by a system approach: Achievements and trends

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw

    1992-01-01

    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.

  11. Achieving Optimal Privacy in Trust-Aware Social Recommender Systems

    NASA Astrophysics Data System (ADS)

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

    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.

  12. Gout: optimizing treatment to achieve a disease cure

    PubMed Central

    Bernal, José Antonio; Quilis, Neus; Andrés, Mariano; Sivera, Francisca; Pascual, Eliseo

    2016-01-01

    Gout is one of the most common inflammatory arthritides. The disease is due to the deposition of monosodium urate crystals. These deposits are reversible with proper treatment, suggesting that gout is a curable disease. The main aim in gout is to lower serum uric acid levels to a pre-established target; there are different urate-lowering drugs (xanthine oxidase inhibitors, uricosurics and uricases) through which this can be achieved. Proper treatment of gout also involves correct management of acute flares and their prevention. To ensure treatment adherence it is necessary to explain to the patient what the objectives are. PMID:26977282

  13. Gout: optimizing treatment to achieve a disease cure.

    PubMed

    Bernal, José Antonio; Quilis, Neus; Andrés, Mariano; Sivera, Francisca; Pascual, Eliseo

    2016-03-01

    Gout is one of the most common inflammatory arthritides. The disease is due to the deposition of monosodium urate crystals. These deposits are reversible with proper treatment, suggesting that gout is a curable disease. The main aim in gout is to lower serum uric acid levels to a pre-established target; there are different urate-lowering drugs (xanthine oxidase inhibitors, uricosurics and uricases) through which this can be achieved. Proper treatment of gout also involves correct management of acute flares and their prevention. To ensure treatment adherence it is necessary to explain to the patient what the objectives are. PMID:26977282

  14. Concurrently adjusting interrelated control parameters to achieve optimal engine performance

    SciTech Connect

    Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

    2015-12-01

    Methods and systems for real-time engine control optimization are provided. A value of an engine performance variable is determined, a value of a first operating condition and a value of a second operating condition of a vehicle engine are detected, and initial values for a first engine control parameter and a second engine control parameter are determined based on the detected first operating condition and the detected second operating condition. The initial values for the first engine control parameter and the second engine control parameter are adjusted based on the determined value of the engine performance variable to cause the engine performance variable to approach a target engine performance variable. In order to cause the engine performance variable to approach the target engine performance variable, adjusting the initial value for the first engine control parameter necessitates a corresponding adjustment of the initial value for the second engine control parameter.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  16. Multiphase Nano-Composite Coatings for Achieving Energy Optimization

    SciTech Connect

    Dr. Jose Nainaparampil

    2012-03-26

    UES Inc. and ANL teamed in this work to develop novel coating systems for the protection of surfaces from thermal degradation mainly in two applications; Machining and Die casting. These coatings were specifically designed for the purpose by incorporating required material phases and the overall architecture, which led to reduce the energy usage and increase efficiency of the operations. Following the UES/ANL'™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.

  17. Achievement Gaps: An Examination of Differences in Student Achievement and Growth. The Full Report

    ERIC Educational Resources Information Center

    McCall, Martha S.; Hauser, Carl; Cronin, John; Kingsbury, G. Gage; Houser, Ronald

    2006-01-01

    The difference between the academic performance of poor students and wealthier students and between minority students and their non-minority peers is commonly known as the achievement gap. The current study examines the achievement gap using a large sample of students from a wide variety of school districts across the United States. It examines…

  18. Optimization of a new mathematical model for bacterial growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research is to optimize a new mathematical equation as a primary model to describe the growth of bacteria under constant temperature conditions. An optimization algorithm was used in combination with a numerical (Runge-Kutta) method to solve the differential form of the new gr...

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    ERIC Educational Resources Information Center

    Airola, Denise Tobin

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Airola, Denise Tobin

    2011-01-01

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

  3. Reading and Math Achievement Profiles and Longitudinal Growth Trajectories of Children with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

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

    2015-01-01

    This study examined the reading and math achievement profiles and longitudinal growth trajectories of a nationally representative sample of children ages 6 through 9 with an autism spectrum disorder. Four distinct achievement profiles were identified: higher-achieving (39%), hyperlexia (9%), hypercalculia (20%) and lower-achieving (32%). Children…

  4. The Effects of Academic Optimism on Student Academic Achievement in Alabama

    ERIC Educational Resources Information Center

    Bevel, Raymona King

    2010-01-01

    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

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

    ERIC Educational Resources Information Center

    Wu, Hsin-Chieh

    2012-01-01

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

  6. The Effects of Academic Optimism on Student Academic Achievement in Alabama

    ERIC Educational Resources Information Center

    Bevel, Raymona King

    2010-01-01

    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…

  7. Test Development with Performance Standards and Achievement Growth in Mind

    ERIC Educational Resources Information Center

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

    2011-01-01

    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…

  8. Test Development with Performance Standards and Achievement Growth in Mind

    ERIC Educational Resources Information Center

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

    2011-01-01

    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

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

    PubMed

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

    2015-02-01

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

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

    ERIC Educational Resources Information Center

    McGuigan, Leigh; Hoy, Wayne K.

    2006-01-01

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

  11. Fully localised nonlinear energy growth optimals in pipe flow

    NASA Astrophysics Data System (ADS)

    Pringle, Chris C. T.; Willis, Ashley P.; Kerswell, Rich R.

    2015-06-01

    A new, fully localised, energy growth optimal is found over large times and in long pipe domains at a given mass flow rate. This optimal emerges at a threshold disturbance energy below which a nonlinear version of the known (streamwise-independent) linear optimal [P. J. Schmid and D. S. Henningson, "Optimal energy density growth in Hagen-Poiseuille flow," J. Fluid Mech. 277, 192-225 (1994)] is selected and appears to remain the optimal up until the critical energy at which transition is triggered. The form of this optimal is similar to that found in short pipes [Pringle et al., "Minimal seeds for shear flow turbulence: Using nonlinear transient growth to touch the edge of chaos," J. Fluid Mech. 702, 415-443 (2012)], but now with full localisation in the streamwise direction. This fully localised optimal perturbation represents the best approximation yet of the minimal seed (the smallest perturbation which is arbitrarily close to states capable of triggering a turbulent episode) for "real" (laboratory) pipe flows. Dependence of the optimal with respect to several parameters has been computed and establishes that the structure is robust.

  12. Fully localised nonlinear energy growth optimals in pipe flow

    SciTech Connect

    Pringle, Chris C. T.; Willis, Ashley P.; Kerswell, Rich R.

    2015-06-15

    A new, fully localised, energy growth optimal is found over large times and in long pipe domains at a given mass flow rate. This optimal emerges at a threshold disturbance energy below which a nonlinear version of the known (streamwise-independent) linear optimal [P. J. Schmid and D. S. Henningson, “Optimal energy density growth in Hagen-Poiseuille flow,” J. Fluid Mech. 277, 192–225 (1994)] is selected and appears to remain the optimal up until the critical energy at which transition is triggered. The form of this optimal is similar to that found in short pipes [Pringle et al., “Minimal seeds for shear flow turbulence: Using nonlinear transient growth to touch the edge of chaos,” J. Fluid Mech. 702, 415–443 (2012)], but now with full localisation in the streamwise direction. This fully localised optimal perturbation represents the best approximation yet of the minimal seed (the smallest perturbation which is arbitrarily close to states capable of triggering a turbulent episode) for “real” (laboratory) pipe flows. Dependence of the optimal with respect to several parameters has been computed and establishes that the structure is robust.

  13. Achieving and documenting closure in plant growth facilities

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  15. Once, Sometimes, or Always in Special Education: Mathematics Growth and Achievement Gaps

    ERIC Educational Resources Information Center

    Schulte, Ann C.; Stevens, Joseph J.

    2015-01-01

    This study used a statewide longitudinal sample to examine mathematics achievement gaps and growth in students with and without disabilities and to examine the impact of different methods of determining disability group membership on achievement gaps and growth. When disability status was determined on the basis of special education placement each…

  16. Summer Study: A Two Part Investigation of the Impact of Exposure to Schooling on Achievement Growth.

    ERIC Educational Resources Information Center

    David, Jane Lisa

    This thesis is composed of two studies which look at the impact of exposure to schooling on achievement growth of children. Both use data from the National Follow Through Evaluation. The first study investigates the hypothesis that the difference in achievement growth between poor and non-poor children is greater during the summer months than…

  17. Tracking Student Achievement in Music Performance: Developing Student Learning Objectives for Growth Model Assessments

    ERIC Educational Resources Information Center

    Wesolowski, Brian C.

    2015-01-01

    Student achievement growth data are increasingly used for assessing teacher effectiveness and tracking student achievement in the classroom. Guided by the student learning objective (SLO) framework, music teachers are now responsible for collecting, tracking, and reporting student growth data. Often, the reported data do not accurately reflect the…

  18. Growth and Achievement Trends of Advanced Placement (AP) Exams in American High Schools

    ERIC Educational Resources Information Center

    Judson, Eugene; Hobson, Angela

    2015-01-01

    This exploratory study examined and compared overall trends in growth and student achievement of the Advanced Placement (AP) program. Using data from the past two decades, analyses indicated there has been steady and extensive growth of AP participation, particularly among underclassmen and some minority groups. However, overall achievement, as…

  19. Tracking Student Achievement in Music Performance: Developing Student Learning Objectives for Growth Model Assessments

    ERIC Educational Resources Information Center

    Wesolowski, Brian C.

    2015-01-01

    Student achievement growth data are increasingly used for assessing teacher effectiveness and tracking student achievement in the classroom. Guided by the student learning objective (SLO) framework, music teachers are now responsible for collecting, tracking, and reporting student growth data. Often, the reported data do not accurately reflect the

  20. High-Achieving and Average Students' Reading Growth: Contrasting School and Summer Trajectories

    ERIC Educational Resources Information Center

    Rambo-Hernandez, Karen E.; McCoach, D. Betsy

    2015-01-01

    Much is unknown about how initially high-achieving students grow academically, especially given the measurement issues inherent in assessing growth for the highest performing students. This study compared initially high-achieving and average students' growth in reading (in a cohort of third-grade students from 2,000 schools) over 3 years.…

  1. Culture Conditions Affecting the Optimal Mycelial Growth of Cystoderma amianthinum

    PubMed Central

    Shim, Sung Mi; Oh, Yun Hee; Lee, Kyung Rim; Kim, Seong Hwan; Im, Kyung Hoan; Kim, Jung Wan; Lee, U Youn; Shim, Jae Ouk; Shim, Mi Ja; Lee, Min Woong; Ro, Hyeon Su; Lee, Hyun Sook

    2005-01-01

    Cystoderma amianthinum, one of edible fungi belongs to Agaricaceae of Basidiomycota, has a good taste and flavor. This study was carried out to obtain the basic informations for the optimum mycelial growth of C. amianthinum. The optimal conditions for the mycelial growth were 25? and pH 5 in potato dextrose agar (PDA). C. amianthinum showed the favorable growth in the PDA and yeast malt extract agar (YMA). The favorable carbon and nitrogen sources promoting mycelial growth were fructose and histidine, respectively. The optimum C/N ratio was about 30 : 1 in case that 1% glucose was supplemented to the basal medium as a carbon source. PMID:24049476

  2. Transaction fees and optimal rebalancing in the growth-optimal portfolio

    NASA Astrophysics Data System (ADS)

    Feng, Yu; Medo, Matúš; Zhang, Liang; Zhang, Yi-Cheng

    2011-05-01

    The growth-optimal portfolio optimization strategy pioneered by Kelly is based on constant portfolio rebalancing which makes it sensitive to transaction fees. We examine the effect of fees on an example of a risky asset with a binary return distribution and show that the fees may give rise to an optimal period of portfolio rebalancing. The optimal period is found analytically in the case of lognormal returns. This result is consequently generalized and numerically verified for broad return distributions and returns generated by a GARCH process. Finally we study the case when investment is rebalanced only partially and show that this strategy can improve the investment long-term growth rate more than optimization of the rebalancing period.

  3. Optimization of Dairy Sludge for Growth of Rhizobium Cells

    PubMed Central

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

    2013-01-01

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

  4. The optimal growth of tropical sea surface temperature anomalies

    SciTech Connect

    Penland, C.; Sardeshmukh, P.D.

    1995-08-01

    It is argued from SST observations for the period 1950-90 that the tropical Indo-Pacific ocean-atmosphere system may be described as a stable linear dynamical system driven by spatially coherent Gaussian white noise. Evidence is presented that the predictable component of SST anomaly growth is associated with the constructive interference of several damped normal modes after an optimal initial structure is set up by the white noise forcing. In particular, El Nino-Southern Oscillation (ENSO) growth is associated with an interplay of at least three damped normal modes, with periods longer than two years and decay times of 4 to 8 months, rather than the manifestation of a single unstable mode whose growth is arrested by nonlinearities. Interestingly, the relevant modes are not the three least damped modes of the system. Rather, mode selection, and the establishment of the optimal initial structure form which growth occurs, are controlled by the stochastic forcing. Experiments conducted with an empirical stochastic-dynamical model show that stochastic forcing not only adds energy to the system, but also plays a role in setting up the optimal structure. It is shown that growth from modal interference can occur for as long as 18 months, which within the confines of this model defines a predictability limit for growth events. Growth associated with the stochastic forcing is also possible, but is unpredictable. The timescale on which the predictable and unpredictable components of SST growth become comparable to each other gives a more conservative predictability limit of 15 months. The above scenario is based on empirical evidence obtained from SST anomalies alone. From the results of several tests based on statistical properties of linear and nonlinear dynamical systems, one may conclude that much of the ENSO cycle in nature is dominated by stable, forced dynamics. 64 refs., 19 figs., 2 tabs.

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

    PubMed Central

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

    2008-01-01

    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. PMID:24031305

  6. Academic Optimism, Organizational Citizenship Behaviors, and Student Achievement at Charter Schools

    ERIC Educational Resources Information Center

    Guvercin, Mustafa

    2013-01-01

    The purpose of this study was to examine the relationship among academic optimism, Organizational Citizenship Behaviors (OCBs), and student achievement in college preparatory charter schools. A purposeful sample of elementary school teachers from college preparatory charter schools (N = 226) in southeast Texas was solicited to complete the…

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

    ERIC Educational Resources Information Center

    Wagner, Charles A.; DiPaola, Michael F.

    2011-01-01

    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…

  8. An Optimal Framework for Smart Growth Decision-Making

    NASA Astrophysics Data System (ADS)

    Moglen, G. E.; Gabriel, S. A.; Faria, J. A.

    2002-05-01

    Increasing awareness about the problems brought on by urban sprawl have led to proactive measures to guide future development. Such efforts have largely been grouped under the term, "Smart Growth". Although not widely recognized as such, the "smart" in smart growth implies an optimization of some quantity or objective while undertaking new forms of urban development. This presentation develops formal definitions of optimal development from the perspectives of four different types of individuals: a government planner, a land developer, a hydrologist, and a conservationist. Four different objective functions are posed that are consistent with each of these individuals' perspectives. We illustrate the differences in consequences on future development given these different objective functions in Montgomery County, Maryland. Differences between the solutions to the various perspectives graphically illustrate that "smart growth" is in the eye of the beholder. The mapped solutions to "smart growth" from the individual perspectives vary considerably. Aside from the obvious differences between these solutions, this presentation will highlight some interesting, but more subtle results, such as the existence of parcels that are considered "optimal" for development across all perspectives. The robustness of such parcels to varied definitions of optimality suggests they reflect a more broadly defined "smart growth". Although couched in the context of an illustrative example, this presentation emphasizes the need to apply rigorous, quantitative tools in a meaningful framework to address smart growth. The result is a tool that a range of parties can use to plan future development in ways that are environmentally and fiscally responsible and economically viable. The details of the construction of this framework involve precise articulation of individual objectives and good communication between all parties with a stake in the future land development.

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

    ERIC Educational Resources Information Center

    Johnson, Ursula Y.; Hull, Darrell M.

    2014-01-01

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

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

    ERIC Educational Resources Information Center

    Education Resource Strategies, 2013

    2013-01-01

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

  11. The Groove of Growth: How Early Gains in Math Ability Influence Adolescent Achievement

    ERIC Educational Resources Information Center

    Watts, Tyler W.; Duncan, Greg J.; Siegler, Robert S.; Davis-Kean, Pamela E.

    2014-01-01

    A number of studies, both small scale and of nationally-representative student samples, have reported substantial associations between school entry math ability and later elementary school achievement. However, questions remain regarding the persistence of the association between early growth in math ability and later math achievement due to the…

  12. Optimal Culture Conditions for Mycelial Growth of Lignosus rhinocerus

    PubMed Central

    Siti Murni, M.J.; Fauzi, D.; Abas Mazni, O.; Saleh, N.M.

    2011-01-01

    Lignosus rhinocerus is a macrofungus that belongs to Polyporaceae and is native to tropical regions. This highly priced mushroom has been used as folk medicine to treat diseases by indigenous people. As a preliminary study to develop a culture method for edible mushrooms, the cultural characteristics of L. rhinocerus were investigated in a range of culture media under different environmental conditions. Mycelial growth of this mushroom was compared on culture media composed of various carbon and nitrogen sources in addition to C/N ratios. The optimal conditions for mycelial growth were 30℃ at pH 6 and 7. Rapid mycelial growth of L. rhinocerus was observed on glucose-peptone and yeast extract peptone dextrose media. Carbon and nitrogen sources promoting mycelial growth of L. rhinocerus were glucose and potassium nitrate, respectively. The optimum C/N ratio was approximately 10 : 1 using 2% glucose supplemented as a carbon source in the basal media. PMID:22783083

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

    NASA Technical Reports Server (NTRS)

    Hajela, P.; Sobieszczanski-Sobieski, J.

    1981-01-01

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

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

    PubMed

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

    2015-02-01

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

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

    PubMed Central

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

    2014-01-01

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

  16. Optimizing growth opportunities during the managed care revolution.

    PubMed

    DeMarco, Bill

    2002-05-01

    Despite reports to the contrary, managed care is pervasive and growing. By understanding employers' needs and how those needs are forcing managed care to change, hospital and physician provider organizations can create growth opportunities for themselves. To optimize their organizations' financial performance under managed care contracts, healthcare financial managers of providers should develop an overall managed care strategy for their organizations that includes customer-service initiatives and system planning and development, instead of focusing only on contract negotiation. PMID:12013640

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

    SciTech Connect

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

    2007-08-20

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

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

    ERIC Educational Resources Information Center

    Grady, Matthew W.; Beretvas, S. Natasha

    2010-01-01

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

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

    ERIC Educational Resources Information Center

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

    2008-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  1. Faculty Sense of Academic Optimism and Its Relationship to Students' Achievement in Well Performing High Schools

    ERIC Educational Resources Information Center

    Cromartie, Michael Tyrone

    2013-01-01

    The aim of this study was to determine the organizational characteristics and behaviors that contribute to sustaining a culture of academic optimism as a mechanism of student achievement. While there is a developing research base identifying both the individual elements of academic optimism as well as the academic optimism construct itself as…

  2. Microalgal growth with intracellular phosphorus for achieving high biomass growth rate and high lipid/triacylglycerol content simultaneously.

    PubMed

    Wu, Yin-Hu; Yu, Yin; Hu, Hong-Ying

    2015-09-01

    Nutrient deprivation is a commonly-used trigger for microalgal lipid accumulation, but its adverse impact on microalgal growth seems to be inevitable. In this study, Scenedesmus sp. LX1 was found to show similar physiological and biochemical variation under oligotrophic and eutrophic conditions during growth with intracellular phosphorus. Under both conditions microalgal chlorophyll content and photosynthesis activity was stable during this growth process, leading to significant increase of single cell weight and size. Therefore, while algal density growth rate dropped significantly to below 1.0 × 10(5)cells mL(-1) d(-1) under oligotrophic condition, the biomass dry weight growth rate still maintained about 40 mg L(-1) d(-1). Meanwhile, the lipid content in biomass and triacylglycerols (TAGs) content in lipids increased significantly to about 35% and 65%, respectively. Thus, high biomass growth rate and high lipid/TAG content were achieved simultaneously at the late growth phase with intracellular phosphorus. Besides, microalgal biomass produced was rich in carbohydrate with low protein content. PMID:26056779

  3. Optimal conditions of mycelia growth of Laetiporus sulphureus sensu lato

    PubMed Central

    Luangharn, Thatsanee; Karunarathna, Samantha C.; Hyde, Kevin D.; Chukeatirote, Ekachai

    2014-01-01

    Laetiporus sulphureus is an edible wood-rotting basidiomycete, growing on decaying logs, stumps, and trunks of many deciduous and coniferous tree species. This fungus produces relatively large striking yellowish or orange-coloured bracket-like fruitbodies. L. sulphureus is widely consumed as a nutritional food because of its fragrance and texture. In this study, two L. sulphureus strains, MFLUCC 12-0546 and MFLUCC 12-0547, isolated from Chiang Rai, Thailand, were investigated for optimal conditions of mycelia growth. Potato dextrose agar and malt extract agar were observed as the favourable medium for mycelia growth. The optimum pH and temperature for the mushroom mycelia were 6–8 and 25–30°C, respectively. PMID:25544934

  4. Evaluating and optimizing horticultural regimes in space plant growth facilities

    NASA Astrophysics Data System (ADS)

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

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

  5. Legionella pneumophilaRequires Polyamines for Optimal Intracellular Growth

    PubMed Central

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

    2011-01-01

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

  6. Legionella pneumophila requires polyamines for optimal intracellular growth.

    PubMed

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

    2011-09-01

    The Gram-negative intracellular pathogen Legionella pneumophila replicates 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. pneumophila expressing a translocation reporter consisting of the Bordetella pertussisa denylate 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 SPE2 induced pseudohyphal growth in S. cerevisiae; thus, we speculated that (i) HtpB induces pseudohyphal growth by activating polyamine synthesis and (ii) L. pneumophila may require exogenous polyamines for growth. A pharmacological inhibitor of SAMDC significantly reduced L. pneumophila replication in L929 mouse cells and U937 macrophages, whereas exogenously added polyamines moderately favored intracellular growth, confirming that polyamines and host SAMDC activity promote L. pneumophila proliferation. Bioinformatic analysis revealed that most known enzymes required for polyamine biosynthesis in bacteria (including SAMDC) are absent in L. pneumophila, further suggesting a need for exogenous polyamines. We hypothesize that HtpB may function to ensure a supply of polyamines in host cells, which are required for the optimal intracellular growth of L. pneumophila. PMID:21742865

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

    ERIC Educational Resources Information Center

    Ma, X.

    2005-01-01

    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…

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

    ERIC Educational Resources Information Center

    Henry, Kimberly L.

    2010-01-01

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

  9. Teacher Morale, Student Engagement, and Student Achievement Growth in Reading: A Correlational Study

    ERIC Educational Resources Information Center

    Sabin, Jenny T.

    2012-01-01

    This research study explored the current state of teacher morale in fourth- and fifth-grade classrooms in three low socioeconomic schools. Additional research questions addressed correlational relationships among the variables of teacher morale, student engagement, and student achievement growth as measured by the North Carolina Teacher Working…

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

    ERIC Educational Resources Information Center

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

    2009-01-01

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

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

    ERIC Educational Resources Information Center

    Wei, Xin; Blackorby, Jose; Schiller, Ellen

    2011-01-01

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

  12. Optimization of biomass composition explains microbial growth-stoichiometry relationships

    USGS Publications Warehouse

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

    2011-01-01

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

  13. Evaluating and optimizing horticultural regimes in space plant growth facilities

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Muller, Patricia Ann

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

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    SciTech Connect

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

    2000-11-16

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

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

    PubMed Central

    Geary, David C.

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  19. Optimal growth of Central and East Pacific ENSO events

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

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

    ERIC Educational Resources Information Center

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

    2004-01-01

    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…

  1. Therapeutic ultrasound optimization for gene delivery: a key factor achieving nuclear DNA localization.

    PubMed

    Duvshani-Eshet, Maayan; Machluf, Marcelle

    2005-11-28

    When applying therapeutic-ultrasound (TUS) for gene-delivery, there is a great need to understand the contribution of different parameters to the transfection process. The aim of this study is to optimize a wide range of parameters associated with the TUS system concurrent with parameters associated with the transfection, achieving high transfection level and efficiency (total number of cells), while localizing the DNA in the nucleus. Exposure of different cell-types (BHK, LNCaP, BCE) to TUS resulted in high gene expression (1200 fold) and efficiency (28%) with minimal loss in cell viability (<20%). The optimal transfection level and efficiency was achieved using TUS at 2 W/cm2 (0.159 MPa), 30% duty cycle (DC) for 30 min (1080 J/cm2), by placing the transducer above the cells. Long-term TUS application was found to overcome the rate-limiting step of this technology-driving DNA to the cell nucleus. The effect of cell density and DNA concentrations were studied. Increasing DNA concentration contributes to the increase in total gene expression, but not necessarily to transfection efficiency. Our findings support the feasibility of TUS to deliver genes to cells and contribute to the understanding of wide range of parameters that affect the capability of TUS to efficiently deliver genes. PMID:16243409

  2. Growth Mixture Modeling of Academic Achievement in Children of Varying Birth Weight Risk

    PubMed Central

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

    2009-01-01

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

  3. Optimizing edible fungal growth and biodegradation of inedible crop residues using various cropping methods.

    PubMed

    Nyochembeng, Leopold M; Beyl, Caula A; Pacumbaba, R P

    2008-09-01

    Long-term manned space flights to Mars require the development of an advanced life support (ALS) ecosystem including efficient food crop production, processing and recycling waste products thereof. Using edible white rot fungi (EWRF) to achieve effective biomass transformation in ALS requires optimal and rapid biodegradative activity on lignocellulosic wastes. We investigated the mycelial growth of Lentinula edodes and Pleurotus ostreatus on processed residues of various crops under various cropping patterns. In single cropping, mycelial growth and fruiting in all strains were significantly repressed on sweet potato and basil. However, growth of the strains was improved when sweet potato and basil residues were paired with rice or wheat straw. Oyster mushroom (Pleurotus) strains were better than shiitake (L. edodes) strains under single, paired, and mixed cropping patterns. Mixed cropping further eliminated the inherent inhibitory effect of sweet potato, basil, or lettuce on fungal growth. Co-cropping fungal species had a synergistic effect on rate of fungal growth, substrate colonization, and fruiting. Use of efficient cropping methods may enhance fungal growth, fruiting, biodegradation of crop residues, and efficiency of biomass recycling. PMID:18155518

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

    PubMed Central

    Templeton, Nancy Smyth; Senzer, Neil

    2012-01-01

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

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

    PubMed Central

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

    We have carried out a detailed investigation of the effect of water content on the electrochemical anodization of Ti in electrolytes consisting of ammonium fluoride, water, and ethylene glycol. We have explored the possible growth of ordered TiO2 nanotubes in the electrolyte with water concentrations from 1 to 100 vol% and the applied voltage from 10 to 150 V, where large diameter (~600 nm) and fast growth rate (~100 µm h-1) have been successfully realized for the self-organized TiO2 nanotube arrays. The achievement benefits from the clear understanding of the effects of both the water content and the anodization voltage on the formation of TiO2 nanotube arrays. We have further shown crystalline formation of TiO2 nanotubes by simple thermal annealing. The mechanisms of the effect of the water content on the diameter and growth rate revealed here should establish a basis for further optimization of the TiO2 nanotube geometries.

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

    NASA Technical Reports Server (NTRS)

    Bole, Brian; Goebel, Kai; Vachtsevanos, George

    2012-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  9. Physiological geroscience: targeting function to increase healthspan and achieve optimal longevity.

    PubMed

    Seals, Douglas R; Justice, Jamie N; LaRocca, Thomas J

    2016-04-15

    Most nations of the world are undergoing rapid and dramatic population ageing, which presents great socio-economic challenges, as well as opportunities, for individuals, families, governments and societies. The prevailing biomedical strategy for reducing the healthcare impact of population ageing has been 'compression of morbidity' and, more recently, to increase healthspan, both of which seek to extend the healthy period of life and delay the development of chronic diseases and disability until a brief period at the end of life. Indeed, a recently established field within biological ageing research, 'geroscience', is focused on healthspan extension. Superimposed on this background are new attitudes and demand for 'optimal longevity' - living long, but with good health and quality of life. A key obstacle to achieving optimal longevity is the progressive decline in physiological function that occurs with ageing, which causes functional limitations (e.g. reduced mobility) and increases the risk of chronic diseases, disability and mortality. Current efforts to increase healthspan centre on slowing the fundamental biological processes of ageing such as inflammation/oxidative stress, increased senescence, mitochondrial dysfunction, impaired proteostasis and reduced stress resistance. We propose that optimization of physiological function throughout the lifespan should be a major emphasis of any contemporary biomedical policy addressing global ageing. Effective strategies should delay, reduce in magnitude or abolish reductions in function with ageing (primary prevention) and/or improve function or slow further declines in older adults with already impaired function (secondary prevention). Healthy lifestyle practices featuring regular physical activity and ideal energy intake/diet composition represent first-line function-preserving strategies, with pharmacological agents, including existing and new pharmaceuticals and novel 'nutraceutical' compounds, serving as potential complementary approaches. Future research efforts should focus on defining the temporal patterns of functional declines with ageing, identifying the underlying mechanisms and modulatory factors involved, and establishing the most effective lifestyle practices and pharmacological options for maintaining function. Continuing development of effective behavioural approaches for enhancing adherence to healthy ageing practices in diverse populations, and ongoing analysis of the socio-economic costs and benefits of healthspan extension will be important supporting goals. To meet the demands created by rapid population ageing, a new emphasis in physiological geroscience is needed, which will require the collaborative, interdisciplinary efforts of investigators working throughout the translational research continuum from basic science to public health. PMID:25639909

  10. Executive Functioning in Individuals with a History of ASDs Who Have Achieved Optimal Outcomes

    PubMed Central

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

    2014-01-01

    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 achievedoptimal 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 NVIQ, but differed on VIQ (HFA

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

    NASA Astrophysics Data System (ADS)

    von Secker, Clare Elaine

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

  12. Constrained growth flips the direction of optimal phenological responses among annual plants.

    PubMed

    Lindh, Magnus; Johansson, Jacob; Bolmgren, Kjell; Lundström, Niklas L P; Brännström, Åke; Jonzén, Niclas

    2016-03-01

    Phenological changes among plants due to climate change are well documented, but often hard to interpret. In order to assess the adaptive value of observed changes, we study how annual plants with and without growth constraints should optimize their flowering time when productivity and season length changes. We consider growth constraints that depend on the plant's vegetative mass: self-shading, costs for nonphotosynthetic structural tissue and sibling competition. We derive the optimal flowering time from a dynamic energy allocation model using optimal control theory. We prove that an immediate switch (bang-bang control) from vegetative to reproductive growth is optimal with constrained growth and constant mortality. Increasing mean productivity, while keeping season length constant and growth unconstrained, delayed the optimal flowering time. When growth was constrained and productivity was relatively high, the optimal flowering time advanced instead. When the growth season was extended equally at both ends, the optimal flowering time was advanced under constrained growth and delayed under unconstrained growth. Our results suggests that growth constraints are key factors to consider when interpreting phenological flowering responses. It can help to explain phenological patterns along productivity gradients, and links empirical observations made on calendar scales with life-history theory. PMID:26548947

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  15. Statistical optimization of medium components and physicochemical parameters to simultaneously enhance bacterial growth and esterase production by Bacillus thuringiensis.

    PubMed

    Mazzucotelli, Cintia Anabela; Moreira, María del Rosario; Ansorena, María Roberta

    2016-01-01

    Bacillus thuringiensis is a genus extensively studied because of its high potential for biotechnological application, principally in biocontrol techniques. However, the optimization of esterase production by this strain has been scarcely studied. The aim of this work was to select and optimize the physicochemical and nutritional parameters that significantly influence the growth and esterase production of B. thuringiensis. To this purpose, 6 nutritional factors and 2 physicochemical parameters were evaluated using a Plackett-Burman design. Significant variables were optimized using a Box-Behnken design and through the desirability function to select the levels of the variables that simultaneously maximize microbial growth and esterase production. The optimum conditions resulting from simultaneous optimization of the responses under study were found to be 1 g/L glucose, 15 g/L peptone, and 3.25 g/L NaCl. Under these optimal conditions, it was possible to achieve a 2.5 log CFU/mL increase in bacterial growth and a 113-fold increase in esterase productivity, compared with minimal medium without agitation. PMID:26529589

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    Crystallographic texture of lead zirconate titanate (PZT) thin films strongly influences piezoelectric properties used in MEMS applications. Textured growth can be achieved by relying on crystal growth habit and can also be initiated by the use of a seed-layer heteroepitaxial template. Template choice and the process used to form it determine structural quality, ultimately influencing performance and reliability of MEMS PZT devices such as switches, filters, and actuators. This study focuses on how 111-textured PZT is generated by a combination of crystal habit and templating mechanisms that occur in the PZT/bottom-electrode stack. The sequence begins with 0001-textured Ti deposited on thermally grown SiO2 on a Si wafer. The Ti is converted to 100-textured TiO2 (rutile) through thermal oxidation. Then 111-textured Pt can be grown to act as a template for 111-textured PZT. Ti and Pt are deposited by DC magnetron sputtering. TiO2 and Pt film textures and structure were optimized by variation of sputtering deposition times, temperatures and power levels, and post-deposition anneal conditions. The relationship between Ti, TiO2, and Pt texture and their impact on PZT growth will be presented. Also affiliated with U.S. Army Research Lab, Adelphi, MD 20783, USA

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

    PubMed

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

    2011-08-01

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

  18. Achieving Consistent Near-Optimal Pattern Recognition Accuracy Using Particle Swarm Optimization to Pre-Train Artificial Neural Networks

    ERIC Educational Resources Information Center

    Nikelshpur, Dmitry O.

    2014-01-01

    Similar to mammalian brains, Artificial Neural Networks (ANN) are universal approximators, capable of yielding near-optimal solutions to a wide assortment of problems. ANNs are used in many fields including medicine, internet security, engineering, retail, robotics, warfare, intelligence control, and finance. "ANNs have a tendency to get

  19. Achieving Consistent Near-Optimal Pattern Recognition Accuracy Using Particle Swarm Optimization to Pre-Train Artificial Neural Networks

    ERIC Educational Resources Information Center

    Nikelshpur, Dmitry O.

    2014-01-01

    Similar to mammalian brains, Artificial Neural Networks (ANN) are universal approximators, capable of yielding near-optimal solutions to a wide assortment of problems. ANNs are used in many fields including medicine, internet security, engineering, retail, robotics, warfare, intelligence control, and finance. "ANNs have a tendency to get…

  20. Should Schools Be Optimistic? An Investigation of the Association between Academic Optimism of Schools and Student Achievement in Primary Education

    ERIC Educational Resources Information Center

    Boonen, Tinneke; Pinxten, Maarten; Van Damme, Jan; Onghena, Patrick

    2014-01-01

    Academic emphasis, collective efficacy, and faculty trust in students and parents (3 school characteristics positively associated with student achievement) are assumed to form a higher order latent construct, "academic optimism" (Hoy, Tarter, & Woolfolk Hoy, 2006a, 2006b). The aim of the present study is to corroborate the latent…

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

    ERIC Educational Resources Information Center

    Chang, I-Hua

    2011-01-01

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

  2. Academic Optimism and Collective Responsibility: An Organizational Model of the Dynamics of Student Achievement

    ERIC Educational Resources Information Center

    Wu, Jason H.

    2013-01-01

    This study was designed to examine the construct of academic optimism and its relationship with collective responsibility in a sample of Taiwan elementary schools. The construct of academic optimism was tested using confirmatory factor analysis, and the whole structural model was tested with a structural equation modeling analysis. The data were…

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  4. Photocurrent enhancement of n-type Cu2O electrodes achieved by controlling dendritic branching growth.

    PubMed

    McShane, Colleen M; Choi, Kyoung-Shin

    2009-02-25

    Cu(2)O electrodes composed of dendritic crystals were produced electrochemically using a slightly acidic medium (pH 4.9) containing acetate buffer. The buffer played a key role for stabilizing dendritic branching growth as a pH drop during the synthesis prevents formation of morphologically unstable branches and promotes faceted growth. Dendritic branching growth enabled facile coverage of the substrate with Cu(2)O while avoiding growth of a thicker Cu(2)O layer and increasing surface areas. The resulting electrodes showed n-type behavior by generating anodic photocurrent without applying an external bias (zero-bias photocurrent under short-circuit condition) in an Ar-purged 0.02 M K(2)SO(4) solution. The zero-bias photocurrent of crystalline dendritic electrodes was significantly higher than that of the electrodes containing micrometer-size faceted crystals deposited without buffer. In order to enhance photocurrent further a strategy of improving charge-transport properties by increasing dendritic crystal domain size was investigated. Systematic changes in nucleation density and size of the dendritic Cu(2)O crystals were achieved by altering the deposition potential, Cu(2+) concentration, and acetate concentration. Increasing dendritic crystal size consistently resulted in the improvement of photocurrent regardless of the method used to regulate crystal size. The electrode composed of dendritic crystals with the lateral dimension of ca. 12000 microm(2) showed more than 20 times higher zero-bias photocurrent than that composed of dendritic crystals with the lateral dimension of ca. 100 microm(2). The n-type nature of the Cu(2)O electrodes prepared by this study were confirmed by linear sweep voltammetry with chopped light and capacitance measurements (i.e., Mott-Schottky plots). The flatband potential in a 0.2 M K(2)SO(4) solution (pH 6) was estimated to be -0.78 vs Ag/AgCl reference electrode. The IPCE measured without applying an external bias was approximately 1% for the visible region. With appropriate doping studies and surface treatment to improve charge transport and interfacial kinetics more efficient n-type Cu(2)O electrodes will be prepared for use in various photoelectrochemical and photovoltaic devices. PMID:19199616

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

    TOXLINE Toxicology Bibliographic Information

    Zhang W; Wang H; Han F; Gao J; Nguyen T; Chen Y; Huang B; Zhan FB; Zhou L; Hong S

    2014-11-01

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

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

    PubMed

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

    2014-11-01

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

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

    PubMed

    Filin, Ido

    2010-05-21

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

  8. Engineering Chinese hamster ovary (CHO) cells to achieve an inverse growth - associated production of a foreign protein, beta-galactosidase.

    PubMed

    Lee, F W; Elias, C B; Todd, P; Kompala, D S

    1998-11-01

    Protein synthesis in mammalian cells can be observed in two strikingly different patterns: 1) production of monoclonal antibodies in hybridoma cultures is typically inverse growth associated and 2) production of most therapeutic glycoproteins in recombinant mammalian cell cultures is found to be growth associated. Production of monoclonal antibodies has been easily maximized by culturing hybridoma cells at very low growth rates in high cell density fed- batch or perfusion bioreactors. Applying the same bioreactor techniques to recombinant mammalian cell cultures results in drastically reduced production rates due to their growth associated production kinetics. Optimization of such growth associated production requires high cell growth conditions, such as in repeated batch cultures or chemostat cultures with attendant excess biomass synthesis. Our recent research has demonstrated that this growth associated production in recombinant Chinese hamster ovary (CHO) cells is related to the S (DNA synthesis)-phase specific production due to the SV40 early promoter commonly used for driving the foreign gene expression. Using the stably transfected CHO cell lines synthesizing an intracellular reporter protein under the control of SV40 early promoter, we have recently demonstrated in batch and continuous cultures that the product synthesis is growth associated. We have now replaced this S-phase specific promoter in new expression vectors with the adenovirus major late promoter which was found to be active primarily in the G1-phase and is expected to yield the desirable inverse growth associated production behavior. Our results in repeated batch cultures show that the protein synthesis kinetics in this resulting CHO cell line is indeed inverse growth associated. Results from continuous and high cell density perfusion culture experiments also indicate a strong inverse growth associated protein synthesis. The bioreactor optimization with this desirable inverse growth associated production behavior would be much simpler than bioreactor operation for cells with growth associated production. PMID:19003409

  9. Optimization of silk films as substrate for functional corneal epithelium growth.

    PubMed

    Jia, Liang; Ghezzi, Chiara E; Kaplan, David L

    2016-02-01

    The corneal epithelium is the first cellular barrier to protect the cornea. Thus, functional tissue engineering of the corneal epithelium is a strategy for clinical transplantation. In this study, the optimization of silk films (SFs) as substrates for functional human corneal epithelium growth was investigated with primary human corneal epithelial cells on SFs, poly-D-lysine (PDL) coated SFs, arginine-glycine-aspartic acid (RGD) modified SFs and PDL blended SFs. PDL coated SFs significantly promoted cell adhesion at early phases in comparison to the other study groups, while PDL blended SF significantly promoted cell migration in a "wound healing" model. All film modifications promoted cell proliferation and viability, and a multi-layered epithelium was achieved in 4 weeks of culture. The epithelia formed were tightly apposed and maintained an intact barrier function against rose bengal dye penetration. The results suggested that a differentiated human corneal epithelium can be established with primary corneal epithelial cells on SFs in vitro, by optimizing SF composition with PDL. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 431-441, 2016. PMID:25891207

  10. Thermal Optimization of Growth and Quality in Protein Crystals

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.

    1996-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    The use of composite pressure vessels particularly in the aerospace industry is escalating rapidly because of their superiority in directional strength and colossal weight advantage. The present work elucidates the procedure to optimize the lay-up for composite pressure vessel using finite element analysis and calculate the relative weight saving compared with the reference metallic pressure vessel. The determination of proper fiber orientation and laminate thickness is very important to decrease manufacturing difficulties and increase structural efficiency. In the present work different lay-up sequences for laminates including, cross-ply [ 0 m /90 n ] s , angle-ply [ ±θ] ns , [ 90/±θ] ns and [ 0/±θ] 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 [ ±θ] 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.

  12. Dynamical Allocation of Cellular Resources as an Optimal Control Problem: Novel Insights into Microbial Growth Strategies

    PubMed Central

    Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc

    2016-01-01

    Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to dynamical environments, using a self-replicator model. We formulate dynamical growth maximization as an optimal control problem that can be solved using Pontryagin’s Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-optimal control strategy in dynamical conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for optimizing growth in a changing environment. PMID:26958858

  13. Dynamical Allocation of Cellular Resources as an Optimal Control Problem: Novel Insights into Microbial Growth Strategies.

    PubMed

    Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc; Geiselmann, Johannes; de Jong, Hidde

    2016-03-01

    Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to dynamical environments, using a self-replicator model. We formulate dynamical growth maximization as an optimal control problem that can be solved using Pontryagin's Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-optimal control strategy in dynamical conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for optimizing growth in a changing environment. PMID:26958858

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

    NASA Astrophysics Data System (ADS)

    Belen-Ferrer, Bellasanta

    2009-12-01

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

  15. Numerical Simulation of a Tumor Growth Dynamics Model Using Particle Swarm Optimization

    PubMed Central

    Wang, Zhijun; Wang, Qing

    2016-01-01

    Tumor cell growth models involve high-dimensional parameter spaces that require computationally tractable methods to solve. To address a proposed tumor growth dynamics mathematical model, an instance of the particle swarm optimization method was implemented to speed up the search process in the multi-dimensional parameter space to find optimal parameter values that fit experimental data from mice cancel cells. The fitness function, which measures the difference between calculated results and experimental data, was minimized in the numerical simulation process. The results and search efficiency of the particle swarm optimization method were compared to those from other evolutional methods such as genetic algorithms.

  16. Growth Trajectories of Mathematics Achievement: Longitudinal Tracking of Student Academic Progress

    ERIC Educational Resources Information Center

    Mok, Magdalena M. C.; McInerney, Dennis M.; Zhu, Jinxin; Or, Anthony

    2015-01-01

    Background: A number of methods to investigate growth have been reported in the literature, including hierarchical linear modelling (HLM), latent growth modelling (LGM), and multidimensional scaling applied to longitudinal profile analysis (LPAMS). Aims: This study aimed at modelling the mathematics growth of students over a span of 6 years from…

  17. Plasticity in the growth of the chick eye: emmetropization achieved by alternate morphologies.

    PubMed

    Wahl, Christina; Li, Tong; Howland, Howard

    2015-05-01

    Both refractive properties of the eyes and ambient light conditions affect emmetropization during growth. Exposure to constant light flattens the cornea making chicks hyperopic. To discover whether and how growing chick eyes restore emmetropia after exposure to constant light (CL) for 3, 7, or 11weeks, we returned chicks to normal (N) conditions with 12h. of light alternating with 12h. of darkness (designated the "R", or recovery, condition) for total periods of 4, 7, 11, or 17weeks. The two control groups were raised in CL conditions or raised in N conditions for the same length of time. We measured anterior chamber depths and lens thicknesses with an A-scan ultrasound machine. We measured corneal curvatures with an eight-axis keratometer, and refractions with conventional retinoscopy. We estimated differences in optical powers of CL, R and N chicks of identical age by constructing ray-tracing models using the above measurements and age-adjusted normal lens curvatures. We also computed the sensitivity of focus for small perturbations of the above optical parameters. Full refractive recovery from CL effects always occurred. Hyperopic refractive errors were absent when R chicks were returned to N for as little as 1week after 3weeks CL treatment. In R chicks exposed to CL for 11weeks and returned to N, axial lengths, vitreous chamber depths and radii of corneal curvatures did not return to normal, although their refractions did. While R chicks can usually recover emmetropia, after long periods of exposure to CL, they cannot recover normal ocular morphology. Emmetropization following CL exposure is achieved primarily by adjusting the relationship between corneal curvature and axial length, resulting in normal refractions. PMID:25765992

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

    NASA Astrophysics Data System (ADS)

    Dewi, C.; Trisilowati

    2015-03-01

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

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

    PubMed

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

    2009-01-01

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

  20. Optimized growth of gold nanobars for energy responsive applications

    NASA Astrophysics Data System (ADS)

    Hobbs, Erik; Johnson, Anthony; Hart, Cacie; Schaefer, David; Kolagani, Rajeswari; Devadas, Mary Sajini

    The aim of this research is to create a reliable protocol for the synthesis of plasmonic gold nano bars for energy responsive applications such as light harvesting. The mechanism of growth in these metallic structures is not fully understood. Symmetry breaking by twinning introduces anisotropy in the shape of the nanostructures. This also results in the formation of highly faceted tip geometries that support the propagation of surface plasmon polaritons. Gold nanobars have been synthesized through chemical reduction in the presence of surfactants: cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP). Synthesis is executed by varying the concentrations of CTAB and PVP, as well as adjusting the growth temperature. The influence of additives such as metal ions will be presented. Resulting plasmonic gold nanobars are viewed using darkfield microscopy and scanning electron microscopy to visualize the nanoparticle product mixture. Atomic force microscopy is employed to measure the length and width of the nanobelts. X-ray diffraction determines the degree of crystallinity in the synthesized gold nanobars.

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  2. Measuring Opportunity to Learn and Achievement Growth: Key Research Issues with Implications for the Effective Education of All Students

    ERIC Educational Resources Information Center

    Elliott, Stephen N.

    2015-01-01

    The related constructs of opportunity to learn (OTL) and achievement growth are fundamental aspects of the current large-scale assessment and accountability system in operation in the United States. For purposes of this article, OTL is defined as the degree to which a teacher dedicates instructional time and content coverage to the intended…

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  4. Particulated growth media for optimal liquid and gaseous fluxes to plant roots in microgravity.

    PubMed

    Jones, S B; Or, D

    1998-01-01

    An important and yet relatively under researched area of plant growth in microgravity, deals with the rooting environment of plants. A comprehensive approach for selecting the physical characteristics of root growth media which optimizes the dynamic availability of water and dissolved nutrients, and gases to plant roots was developed and tested. Physically-based and parametric models describing the relationship between content and fluxes of liquids and gases were used to cast a multi-objective optimization problem. This methodology reveals that a medium's ability to supply liquid and gas fluxes optimally is dependent upon physiological target values, system operation limits and root module design which dictate the medium's range of soil water characteristic and particle size distribution. Optimized media parameters designate a particle size distribution from which a particulated growth media was constructed and matched to the optimized media parameters. This methodology should improve the selection of optimal media properties for plant growth in microgravity as well as other porous media applications. PMID:11542601

  5. Growth by Optimization of Work (GROW): A new modeling tool that predicts fault growth through work minimization

    NASA Astrophysics Data System (ADS)

    McBeck, Jessica A.; Madden, Elizabeth H.; Cooke, Michele L.

    2016-03-01

    Growth by Optimization of Work (GROW) is a new modeling tool that automates fracture initiation, propagation, interaction, and linkage. GROW predicts fracture growth by finding the propagation path and fracture geometry that optimizes the global external work of the system. This implementation of work optimization is able to simulate more complex paths of fracture growth than energy release rate methods. In addition, whereas a Coulomb stress analysis determines two conjugate planes of potential failure, GROW identifies a single failure surface for each increment of growth. GROW also eliminates ambiguity in determining whether shear or tensile failure will occur at a fracture tip by assessing both modes of failure by the same propagation criterion. Here we describe the underlying algorithm of the program and present GROW models of two propagating faults separated by a releasing step. The discretization error of these models demonstrates that GROW can predict fault propagation paths within the numerical uncertainty produced by discretization. Model element size moderately influences the propagation paths, however, the final fault geometry remains similar between models with significantly different element sizes. The propagation power of the fault system, calculated from the change in work due to fault propagation, indicates when model faults interact through both soft- and hard-linkage.

  6. Selection of optimal measures of growth and reproduction for the sublethal Leptocheirus plumulosus sediment bioassay

    SciTech Connect

    Gray, B.R.; Wright, R.B.; Duke, B.M.; Farrar, J.D.; Emery, V.L. Jr.; Brandon, D.L.; Moore, D.W.

    1998-11-01

    This article describes the selection process used to identify optimal measures of growth and reproduction for the proposed 28-d sublethal sediment bioassay with the estuarine amphipod Leptocheirus plumulosus. The authors used four criteria (relevance of each measure to its respective endpoint, signal-to-noise ratio, redundancy relative to other measures of the same endpoint, and cost) to evaluate nine growth and seven reproductive measures. Optimal endpoint measures were identified as those receiving relatively high scores for all or most criteria. Measures of growth scored similarly on all criteria, except for cost. The cost of the pooled (female plus male) growth measures was substantially lower than the cost of the female and male growth measures because the latter required more labor (by approx. 25 min per replicate). Pooled dry weight was identified as the optimal growth measure over pooled length because the latter required additional labor and nonstandard software and equipment. Embryo and neonate measures of reproduction exhibited wide differences in labor costs but yielded similar scores for other criteria. In contrast, brooding measures of reproduction scored relatively low on endpoint relevance, signal-to-noise ratio, and redundancy criteria. The authors recommend neonates/survivor as the optimal measure of L. plumulosus reproduction because it exhibited high endpoint relevance and signal-to-noise ratios, was redundant to other reproductive measures, and required minimal time.

  7. High direct drive illumination uniformity achieved by multi-parameter optimization approach: a case study of Shenguang III laser facility.

    PubMed

    Tian, Chao; Chen, Jia; Zhang, Bo; Shan, Lianqiang; Zhou, Weimin; Liu, Dongxiao; Bi, Bi; Zhang, Feng; Wang, Weiwu; Zhang, Baohan; Gu, Yuqiu

    2015-05-01

    The uniformity of the compression driver is of fundamental importance for inertial confinement fusion (ICF). In this paper, the illumination uniformity on a spherical capsule during the initial imprinting phase directly driven by laser beams has been considered. We aim to explore methods to achieve high direct drive illumination uniformity on laser facilities designed for indirect drive ICF. There are many parameters that would affect the irradiation uniformity, such as Polar Direct Drive displacement quantity, capsule radius, laser spot size and intensity distribution within a laser beam. A novel approach to reduce the root mean square illumination non-uniformity based on multi-parameter optimizing approach (particle swarm optimization) is proposed, which enables us to obtain a set of optimal parameters over a large parameter space. Finally, this method is applied to improve the direct drive illumination uniformity provided by Shenguang III laser facility and the illumination non-uniformity is reduced from 5.62% to 0.23% for perfectly balanced beams. Moreover, beam errors (power imbalance and pointing error) are taken into account to provide a more practical solution and results show that this multi-parameter optimization approach is effective. PMID:25969321

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

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  9. The Impact of SMART Board Technology on Growth in Mathematics Achievement of Gifted Learners

    ERIC Educational Resources Information Center

    Riska, Patricia A.

    2010-01-01

    This study examined whether SMART Board technology increased growth in mathematics performance of fourth grade gifted students. Gifted students in North Carolina were studied to determine if the use of SMART Board technology during mathematics instruction impacted their growth on standardized state tests. The sample consisted of 175 students from…

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

    ERIC Educational Resources Information Center

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

    2008-01-01

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

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

    ERIC Educational Resources Information Center

    Warne, Russell T.

    2014-01-01

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

  12. Standardization and Optimization of Computed Tomography Protocols to Achieve Low-Dose

    PubMed Central

    Chin, Cynthia; Cody, Dianna D.; Gupta, Rajiv; Hess, Christopher P.; Kalra, Mannudeep K.; Kofler, James M.; Krishnam, Mayil S.; Einstein, Andrew J.

    2014-01-01

    The increase in radiation exposure due to CT scans has been of growing concern in recent years. CT scanners differ in their capabilities and various indications require unique protocols, but there remains room for standardization and optimization. In this paper we summarize approaches to reduce dose, as discussed in lectures comprising the first session of the 2013 UCSF Virtual Symposium on Radiation Safety in Computed Tomography. The experience of scanning at low dose in different body regions, for both diagnostic and interventional CT procedures, is addressed. An essential primary step is justifying the medical need for each scan. General guiding principles for reducing dose include tailoring a scan to a patient, minimizing scan length, use of tube current modulation and minimizing tube current, minimizing-tube potential, iterative reconstruction, and periodic review of CT studies. Organized efforts for standardization have been spearheaded by professional societies such as the American Association of Physicists in Medicine. Finally, all team members should demonstrate an awareness of the importance of minimizing dose. PMID:24589403

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

    PubMed

    Davis, Brenda C; Kris-Etherton, Penny M

    2003-09-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

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

    SciTech Connect

    Duncan, T. Pasik Duncan, B.; Stettner, L.

    2011-02-15

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

  16. Combinatorial chips for optimizing the growth and integration of carbon nanofibre based devices

    NASA Astrophysics Data System (ADS)

    Cassell, Alan M.; Ye, Qi; Cruden, Brett A.; Li, Jun; Sarrazin, Philippe C.; Tee Ng, Hou; Han, Jie; Meyyappan, M.

    2004-01-01

    The growth of carbon nanofibres (CNF) by plasma enhanced chemical vapour deposition (PECVD) and the integration of CNFs into devices are studied using high throughput methodology. A growth compatibility chip containing candidate metal contact underlayers and transition metal catalyst layers are used to explore growth activity from various pairings of these two layers. In addition, catalyst density microarray chips (CDMCs) where each chip consists of catalyst patterns with various feature sizes and densities were used to investigate CNF growth and integration. The CDMCs were used to efficiently explore CNF growth conditions as well as subsequent downstream integration and testing for applications in ultrasensitive biosensing and field emission. The methodology described here is widely applicable as a general approach for optimizing the bottom-up growth and integration of nanostructures.

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

    PubMed Central

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

    2012-01-01

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

  18. Entrepreneurship Education in Delta State Tertiary Institution as a Means of Achieving National Growth and Development

    ERIC Educational Resources Information Center

    Osakwe, Regina N.

    2015-01-01

    This study examined entrepreneurship education in Delta Sate tertiary institutions as a means of national growth and development. Two research questions were asked to guide the study. The population comprised all the 1,898 academic staff in eight tertiary institutions in the state. A sample of 800 lecturers was drawn through the multi stage and…

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

    ERIC Educational Resources Information Center

    Beecher, Constance C.

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Goosby, Bridget J.; Cheadle, Jacob E.

    2009-01-01

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

  1. Cultivating a Growth Mindset in Students at a High-Achieving High School

    ERIC Educational Resources Information Center

    Fegley, Alan D.

    2010-01-01

    The purpose of this EPP is to develop a plan for changing the mindset of a large number of Haddonfield Memorial High School (HMHS) students from a fixed mindset to a growth mindset. HMHS is by most conventional measures a high performing school. Typically 100% of the students graduate with 96% of the students attending two or four year colleges…

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

    EPA Science Inventory

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

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

    ERIC Educational Resources Information Center

    Lightsey, Owen Richard, Jr.

    1997-01-01

    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)

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  5. Biodegradation of kerosene: Study of growth optimization and metabolic fate of P. janthinellum SDX7

    PubMed Central

    Khan, Shamiyan R.; Nirmal, J.I. Kumar; Kumar, Rita N.; Patel, Jignasha G.

    2015-01-01

    Penicillum janthinellum SDX7 was isolated from aged petroleum hydrocarbon-affected soil at the site of Anand, Gujarat, India, and was tested for different pH, temperature, agitation and concentrations for optimal growth of the isolate that was capable of degrading upto 95%, 63% and 58% of 1%, 3% and 5% kerosene, respectively, after a period of 16 days, at optimal growth conditions of pH 6.0, 30 °C and 180 rpm agitation. The GC/MS chromatograms revealed that then-alkane fractions are easily degraded; however, the rate might be lower for branched alkanes, n-alkylaromatics, cyclic alkanes and polynuclear aromatics. The test doses caused a concentration-dependent depletion of carbohydrates of P. janthinellum SDX7 by 3% to 80%, proteins by 4% to 81% and amino acids by 8% to 95% upto 16 days of treatment. The optimal concentration of 3% kerosene resulted in the least reduction of the metabolites of P. janthinellum such as carbohydrates, proteins and amino acids with optimal growth compared to 5% and 1% (v/v) kerosene doses on the 12th and 16th day of exposure. Phenols were found to be mounted by 43% to 66% at lower and higher concentrations during the experimental period. Fungal isolate P. janthinellum SDX7 was also tested for growth on various xenobiotic compounds. PMID:26273254

  6. Biodegradation of kerosene: Study of growth optimization and metabolic fate of P. janthinellum SDX7.

    PubMed

    Khan, Shamiyan R; Nirmal, J I Kumar; Kumar, Rita N; Patel, Jignasha G

    2015-06-01

    Penicillum janthinellum SDX7 was isolated from aged petroleum hydrocarbon-affected soil at the site of Anand, Gujarat, India, and was tested for different pH, temperature, agitation and concentrations for optimal growth of the isolate that was capable of degrading upto 95%, 63% and 58% of 1%, 3% and 5% kerosene, respectively, after a period of 16 days, at optimal growth conditions of pH 6.0, 30 °C and 180 rpm agitation. The GC/MS chromatograms revealed that then-alkane fractions are easily degraded; however, the rate might be lower for branched alkanes, n-alkylaromatics, cyclic alkanes and polynuclear aromatics. The test doses caused a concentration-dependent depletion of carbohydrates of P. janthinellum SDX7 by 3% to 80%, proteins by 4% to 81% and amino acids by 8% to 95% upto 16 days of treatment. The optimal concentration of 3% kerosene resulted in the least reduction of the metabolites of P. janthinellum such as carbohydrates, proteins and amino acids with optimal growth compared to 5% and 1% (v/v) kerosene doses on the 12(th) and 16(th) day of exposure. Phenols were found to be mounted by 43% to 66% at lower and higher concentrations during the experimental period. Fungal isolate P. janthinellum SDX7 was also tested for growth on various xenobiotic compounds. PMID:26273254

  7. Cloning and Optimization of Soluble Vascular Endothelial Growth Factor165 Expression in Escherichia coli

    PubMed Central

    Salimi, Ali; Babashamsi, Mohammad

    2016-01-01

    Background: Vascular Endothelial Growth Factor (VEGF) is a coordinate regulator of physiological angiogenesis during embryogenesis, skeletal growth and reproductive functions. There are several types of VEGF, including VEGF165. VEGFs stimulate endothelial cell growth, angiogenesis, and capillary permeability. Low induction temperature is a major factor for expression of the recombinant VEGF165 in soluble form. The purpose of this study was cloning and optimization of soluble vascular endothelial growth factor165 expression in Escherichia coli (E. coli). Methods: In this study, total RNA of HeLa cell [cervix epithelium] was extracted. The VEGF165 gene was amplified by reverse transcription polymerase chain reaction (RTPCR), and then VEGF165 was subcloned into prokaryotic expression vectors pET-32a(+) and transformed into BL21 (DE3) E. coli strain. VEGF165 expression was optimized by fine adjustments such as induction time and incubation temperature. VEGF165 was analyzed by DNA sequencing prior to expression and the protein was further characterized by SDS-PAGE and immunoblotting using His•tag specific polyclonal antibody. Results: Our results demonstrated that VEGF165 was successfully cloned and expressed in pET-32a(+) vector. Optimization of the expression procedure showed that, induction by 1 mM IPTG at OD600=0.7 and overnight incubation at 22°C resulted in the highest expression levels of soluble VEGF165. Conclusion: In this study, the expression of VEGF165 in a high soluble level was successfully cloned and optimized. PMID:26855732

  8. Measuring the Impact of Substance Abuse on Student Academic Achievement and Academic Growth

    ERIC Educational Resources Information Center

    Rattermann, Mary Jo

    2014-01-01

    This research presents data linking the impact of substance disorder to academic achievement, using data gathered at a recovery high school. Recovery schools provide recovery supports and a high-quality education to students with substance use disorders. The Global Appraisal of Individual Needs -- Short Screener and the Northwest Evaluation

  9. Emotions, Self-Regulated Learning, and Achievement in Mathematics: A Growth Curve Analysis

    ERIC Educational Resources Information Center

    Ahmed, Wondimu; van der Werf, Greetje; Kuyper, Hans; Minnaert, Alexander

    2013-01-01

    The purpose of the current study was twofold: (a) to investigate the developmental trends of 4 academic emotions (anxiety, boredom, enjoyment, and pride) and (b) to examine whether changes in emotions are linked to the changes in students' self-regulatory strategies (shallow, deep, and meta-cognitive) and achievement in mathematics. Four hundred

  10. Utilizing Precision Teaching To Measure Growth of Reading Comprehension Skills in Low Achieving Students.

    ERIC Educational Resources Information Center

    Nitti, Joanne M.

    A practicum addressed the problem of reading comprehension skills in low achieving students by monitoring their progress utilizing precision teaching. Based on referrals from classroom teachers, guidance counselors, and parents, five students ranging in ability levels from kindergarten through grade 8 were accepted into the program for one or more…

  11. Predictors of Early Growth in Academic Achievement: The Head-Toes-Knees-Shoulders Task

    ERIC Educational Resources Information Center

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

    2014-01-01

    Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by…

  12. Discriminant Effects of Performance-Oriented and Structure-Oriented Mathematics Tasks on Achievement Growth.

    ERIC Educational Resources Information Center

    Renkl, Alexander; Helmke, Andreas

    1992-01-01

    Associations between performance-oriented and structure-oriented tasks in elementary school mathematics instruction and achievement were studied for 33 third grade classrooms. A mathematics pretest and posttest were administered, and classroom observations were conducted. Results suggest that performance-oriented tasks promote automatization of…

  13. Emotions, Self-Regulated Learning, and Achievement in Mathematics: A Growth Curve Analysis

    ERIC Educational Resources Information Center

    Ahmed, Wondimu; van der Werf, Greetje; Kuyper, Hans; Minnaert, Alexander

    2013-01-01

    The purpose of the current study was twofold: (a) to investigate the developmental trends of 4 academic emotions (anxiety, boredom, enjoyment, and pride) and (b) to examine whether changes in emotions are linked to the changes in students' self-regulatory strategies (shallow, deep, and meta-cognitive) and achievement in mathematics. Four hundred…

  14. Measuring the Impact of Substance Abuse on Student Academic Achievement and Academic Growth

    ERIC Educational Resources Information Center

    Rattermann, Mary Jo

    2014-01-01

    This research presents data linking the impact of substance disorder to academic achievement, using data gathered at a recovery high school. Recovery schools provide recovery supports and a high-quality education to students with substance use disorders. The Global Appraisal of Individual Needs -- Short Screener and the Northwest Evaluation…

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

    ERIC Educational Resources Information Center

    Mackinnon, Sean P.

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Hinkle, Rachelle Whittaker

    2011-01-01

    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

  17. Reduction of exposure to acrylamide: achievements, potential of optimization, and problems encountered from the perspectives of a Swiss enforcement laboratory.

    PubMed

    Grob, Koni

    2005-01-01

    The most important initiatives taken in Switzerland to reduce exposure of consumers to acrylamide are the separate sale of potatoes low in reducing sugars for roasting and frying, the optimization of the raw material and preparation of french fries, and campaigns to implement suitable preparation methods in the gastronomy and homes. Industry works on improving a range of other products. Although these measures can reduce high exposures by some 80%, they have little effect on the background exposure resulting from coffee, bread, and numerous other products for which no substantial improvement is in sight. At this stage, improvements should be achieved by supporting voluntary activity rather than legal limits. Committed and consistent risk communication is key, and the support of improvements presupposes innovative approaches. PMID:15759749

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

    PubMed

    Chambers, James Alan; Ray, Peter Damian

    2009-11-01

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

  19. Optimization Correction Strength Using Contra Bending Technique without Anterior Release Procedure to Achieve Maximum Correction on Severe Adult Idiopathic Scoliosis

    PubMed Central

    Rahyussalim, Ahmad Jabir; Saleh, Ifran; Purnaning, Dyah; Kurniawati, Tri

    2016-01-01

    Adult scoliosis is defined as a spinal deformity in a skeletally mature patient with a Cobb angle of more than 10 degrees in the coronal plain. Posterior-only approach with rod and screw corrective manipulation to add strength of contra bending manipulation has correction achievement similar to that obtained by conventional combined anterior release and posterior approach. It also avoids the complications related to the thoracic approach. We reported a case of 25-year-old male adult idiopathic scoliosis with double curve. It consists of main thoracic curve of 150 degrees and lumbar curve of 89 degrees. His curve underwent direct contra bending posterior approach using rod and screw corrective manipulation technique to achieve optimal correction. After surgery the main thoracic Cobb angle becomes 83 degrees and lumbar Cobb angle becomes 40 degrees, with 5 days length of stay and less than 800 mL blood loss during surgery. There is no complaint at two months after surgery; he has already come back to normal activity with good functional activity. PMID:27064801

  20. On growth-optimal tax rates and the issue of wealth inequalities

    NASA Astrophysics Data System (ADS)

    Bouchaud, Jean-Philippe

    2015-11-01

    We introduce a highly stylized, yet non trivial model of the economy, with a public and private sector coupled through a wealth tax and a redistribution policy. The model can be fully solved analytically, and allows one to address the question of optimal taxation and of wealth inequalities. We find that according to the assumption made on the relative performance of public and private sectors, three situations are possible. Not surprisingly, the optimal wealth tax rate is either 0% for a deeply dysfunctional government and/or highly productive private sector, or 100 % for a highly efficient public sector and/or debilitated/risk averse private investors. If the gap between the public/private performance is moderate, there is an optimal positive wealth tax rate maximizing economic growth, even -- counter-intuitively -- when the private sector generates more growth. The compromise between profitable private investments and taxation however leads to a residual level of inequalities. The mechanism leading to an optimal growth rate is related the well-known explore/exploit trade-off.

  1. Rayleigh-Bénard-Poiseuille flow: Optimal growth of streamwise-uniform disturbances

    NASA Astrophysics Data System (ADS)

    Soundar Jerome, J. John; Chomaz, Jean-Marc; Huerre, Patrick

    2011-11-01

    An investigation of the dominant transient growth mechanisms in plane Poiseuille flow subjected to a destabilizing cross-stream temperature gradient is presented. It was pointed out by the same authors in DFD meeting 2009 that only the streamwise-uniform and nearly-streamwise-uniform disturbances are highly influenced by the Rayleigh number Ra and Prandtl number Pr. Here, it is demonstrated that the short-time behavior is governed by the classical inviscid lift-up mechanism and the optimal input for the largest long-time response is given by the adjoint of the dominant eigenmode with respect to the energy scalar product: the Rayleigh-Bénard eigenmode without its streamwise velocity component. These short and long-time responses are then shown to depict, up to leading order, the optimal transient growth G(t). It is thereby brought out that, at moderately large Ra (or small Pr at a fixed Ra), the dominant adjoint mode is a good approximation to the optimal initial condition for all time. The results remain qualitatively similar over a general class of norms that can be considered as growth functions. For instance, the dominant adjoint eigenmode still approximates the maximum optimal response.

  2. Oligodendrocyte progenitors balance growth with self-repulsion to achieve homeostasis in the adult brain

    PubMed Central

    Hughes, E. G.; Kang, S. H.; Fukaya, M.; Bergles, D. E.

    2013-01-01

    The adult CNS contains an abundant population of oligodendrocyte precursor cells (NG2+ cells) that generate oligodendrocytes and repair myelin, but how these ubiquitous progenitors maintain their density is unknown. Here we generated NG2-mEGFP mice and used in vivo two-photon imaging to study their dynamics in the adult brain. Time-lapse imaging revealed that NG2+ cells in the cortex are highly dynamic; they survey their local environment with motile filopodia, extend growth cones, and continuously migrate. They maintain unique territories through self-avoidance, and NG2+ cell loss through death, differentiation, or ablation triggered rapid migration and proliferation of adjacent cells to restore their density. NG2+ cells recruited to sites of focal CNS injury were similarly replaced by a proliferative burst surrounding the injury site. Thus, homeostatic control of NG2+ cell density through a balance of active growth and self-repulsion ensures that these progenitors are available to replace oligodendrocytes and participate in tissue repair. PMID:23624515

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

    PubMed Central

    2014-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Grotenhuis, T. P.; Bugbee, B.

    1997-01-01

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

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

    PubMed

    Grotenhuis, T P; Bugbee, B

    1997-01-01

    Although terrestrial atmospheric CO2 levels will not reach 1000 micromoles mol-1 (0.1%) for decades, CO2 levels in growth chambers and greenhouses routinely exceed that concentration. CO2 levels in life support systems in space can exceed 10000 micromoles mol-1(1%). Numerous studies have examined CO2 effects up to 1000 micromoles mol-1, but biochemical measurements indicate that the beneficial effects of CO2 can continue beyond this concentration. We studied the effects of near-optimal (approximately 1200 micromoles mol-1) and super-optimal CO2 levels (2400 micromoles mol-1) on yield of two cultivars of hydroponically grown wheat (Triticum aestivum L.) in 12 trials in growth chambers. Increasing CO2 from sub-optimal to near-optimal (350-1200 micromoles mol-1) increased vegetative growth by 25% and seed yield by 15% in both cultivars. Yield increases were primarily the result of an increased number of heads per square meter. Further elevation of CO2 to 2500 micromoles mol-1 reduced seed yield by 22% (P < 0.001) in cv. Veery-10 and by 15% (P < 0.001) in cv. USU-Apogee. Super-optimal CO2 did not decrease the number of heads per square meter, but reduced seeds per head by 10% and mass per seed by 11%. The toxic effect of CO2 was similar over a range of light levels from half to full sunlight. Subsequent trials revealed that super-optimal CO2 during the interval between 2 wk before and after anthesis mimicked the effect of constant super-optimal CO2. Furthermore, near-optimal CO2 during the same interval mimicked the effect of constant near-optimal CO2. Nutrient concentration of leaves and heads was not affected by CO2. These results suggest that super-optimal CO2 inhibits some process that occurs near the time of seed set resulting in decreased seed set, seed mass, and yield. PMID:11543367

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

    ERIC Educational Resources Information Center

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

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

  7. Enhanced Production of Insulin-like Growth Factor I Protein in Escherichia coli by Optimization of Five Key Factors.

    PubMed

    Ranjbari, Javad; Babaeipour, Valiollah; Vahidi, Hossein; Moghimi, Hamidreza; Mofid, Mohammad Reza; Namvaran, Mohammad Mehdi; Jafari, Sevda

    2015-01-01

    Human insulin-like growth factor I (hIGF-I) is a kind of growth factor with clinical significance in medicine. Up to now, E. coli expression system has been widely used as a host to produce rhIGF-1 with high yields. Batch cultures as non-continuous fermentations were carried out to overproduce rhIGF-I in E. coli. The major objective of this study is over- production of recombinant human insulin-like growth factor I (rhIGF-I) through a developed process by recruiting effective factors in order to achieve the most recombinant protein. In this study we investigated the effect of culture medium, induction temperature and amount of inducer on cell growth and IGF-1 production. Taguchi design of experiments (DOE) method was used as the statistical method. Analysis of experimental data showed that maximum production of rhIGF-I was occurred in 32y culture medium at 32 °C and 0.05 Mm IPTG. Under this condition, 0.694 g/L of rhIGF-I was produced as the inclusion bodies. Following optimization of these three factors, we have also optimized the amount of glucose and induction time in 5 liter top bench bioreactor. Full factorial design of experiment method was used for these two factors as the statistical method. 10 g/L and OD600=5 were selected as the optimum point of Glucose amount and induction time, respectively. Finally, we reached to a concentration of 1.26 g/L rhIGF-1 at optimum condition. PMID:26330880

  8. Enhanced Production of Insulin-like Growth Factor I Protein in Escherichia coli by Optimization of Five Key Factors

    PubMed Central

    Ranjbari, Javad; Babaeipour, Valiollah; Vahidi, Hossein; Moghimi, Hamidreza; Mofid, Mohammad Reza; Namvaran, Mohammad Mehdi; Jafari, Sevda

    2015-01-01

    Human insulin-like growth factor I (hIGF-I) is a kind of growth factor with clinical significance in medicine. Up to now, E. coli expression system has been widely used as a host to produce rhIGF-1 with high yields. Batch cultures as non-continuous fermentations were carried out to overproduce rhIGF-I in E. coli. The major objective of this study is over- production of recombinant human insulin-like growth factor I (rhIGF-I) through a developed process by recruiting effective factors in order to achieve the most recombinant protein. In this study we investigated the effect of culture medium, induction temperature and amount of inducer on cell growth and IGF-1 production. Taguchi design of experiments (DOE) method was used as the statistical method. Analysis of experimental data showed that maximum production of rhIGF-I was occurred in 32y culture medium at 32 °C and 0.05 Mm IPTG. Under this condition, 0.694 g/L of rhIGF-I was produced as the inclusion bodies. Following optimization of these three factors, we have also optimized the amount of glucose and induction time in 5 liter top bench bioreactor. Full factorial design of experiment method was used for these two factors as the statistical method. 10 g/L and OD600=5 were selected as the optimum point of Glucose amount and induction time, respectively. Finally, we reached to a concentration of 1.26 g/L rhIGF-1 at optimum condition. PMID:26330880

  9. Optimize Flue Gas Settings to Promote Microalgae Growth in Photobioreactors via Computer Simulations

    PubMed Central

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

    2013-01-01

    Flue gas from power plants can promote algal cultivation and reduce greenhouse gas emissions1. Microalgae not only capture solar energy more efficiently than plants3, but also synthesize advanced biofuels2-4. Generally, atmospheric CO2 is not a sufficient source for supporting maximal algal growth5. On the other hand, the high concentrations of CO2 in industrial exhaust gases have adverse effects on algal physiology. Consequently, both cultivation conditions (such as nutrients and light) and the control of the flue gas flow into the photo-bioreactors are important to develop an efficient “flue gas to algae” system. Researchers have proposed different photobioreactor configurations4,6 and cultivation strategies7,8 with flue gas. Here, we present a protocol that demonstrates how to use models to predict the microalgal growth in response to flue gas settings. We perform both experimental illustration and model simulations to determine the favorable conditions for algal growth with flue gas. We develop a Monod-based model coupled with mass transfer and light intensity equations to simulate the microalgal growth in a homogenous photo-bioreactor. The model simulation compares algal growth and flue gas consumptions under different flue-gas settings. The model illustrates: 1) how algal growth is influenced by different volumetric mass transfer coefficients of CO2; 2) how we can find optimal CO2 concentration for algal growth via the dynamic optimization approach (DOA); 3) how we can design a rectangular on-off flue gas pulse to promote algal biomass growth and to reduce the usage of flue gas. On the experimental side, we present a protocol for growing Chlorella under the flue gas (generated by natural gas combustion). The experimental results qualitatively validate the model predictions that the high frequency flue gas pulses can significantly improve algal cultivation. PMID:24121788

  10. Nutritional assessment by comparative growth achievement in Malay children below school age.

    PubMed

    McKay, D A; Lim, R K; Notaney, K H; Dugdale, A E

    1971-01-01

    Measurements of child growth have become the most accepted means of assessing the protein-calorie nutritional status of economically developing populations. International reference standards have been suggested for a number of body measurements, but there has been little evaluation of their applicability in South-East Asia.In order to delineate the present range of nutritional standards in West Malaysia, and to aid in the development of guidelines for further nutritional work in this region, anthropometric tests were made on 3 groups of children below school age belonging to the Malay ethnic group and living under diverse conditions. Children of Malaysian Army personnel differed significantly in most measurements from rural village children in Trengganu and children from a small urban elite in Kuala Lumpur. Measurements for the latter group approximated to internationally used standards of height and weight. Parental height data suggest that these differences are not primarily genetic. Anaemia, malaria, and ascariasis were common among the Trengganu children.Weight and height emerge as the measurements that are most sensitive in differentiating between the groups; arm circumferences and skinfold measurements are also useful because they are relatively independent of age. Measurement of chest and head circumferences and of crown-rump lengths appeared to be of little value. PMID:5316620

  11. Nutritional assessment by comparative growth achievement in Malay children below school age*

    PubMed Central

    McKay, D. A.; Lim, R. K. H.; Notaney, K. H.; Dugdale, A. E.

    1971-01-01

    Measurements of child growth have become the most accepted means of assessing the protein-calorie nutritional status of economically developing populations. International reference standards have been suggested for a number of body measurements, but there has been little evaluation of their applicability in South-East Asia. In order to delineate the present range of nutritional standards in West Malaysia, and to aid in the development of guidelines for further nutritional work in this region, anthropometric tests were made on 3 groups of children below school age belonging to the Malay ethnic group and living under diverse conditions. Children of Malaysian Army personnel differed significantly in most measurements from rural village children in Trengganu and children from a small urban elite in Kuala Lumpur. Measurements for the latter group approximated to internationally used standards of height and weight. Parental height data suggest that these differences are not primarily genetic. Anaemia, malaria, and ascariasis were common among the Trengganu children. Weight and height emerge as the measurements that are most sensitive in differentiating between the groups; arm circumferences and skinfold measurements are also useful because they are relatively independent of age. Measurement of chest and head circumferences and of crown—rump lengths appeared to be of little value. PMID:5316620

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

    SciTech Connect

    Lyashenko, O.I.

    1995-12-10

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

  13. Accurate estimation of cardinal growth temperatures of Escherichia coli from optimal dynamic experiments.

    PubMed

    Van Derlinden, E; Bernaerts, K; Van Impe, J F

    2008-11-30

    Prediction of the microbial growth rate as a response to changing temperatures is an important aspect in the control of food safety and food spoilage. Accurate model predictions of the microbial evolution ask for correct model structures and reliable parameter values with good statistical quality. Given the widely accepted validity of the Cardinal Temperature Model with Inflection (CTMI) [Rosso, L., Lobry, J. R., Bajard, S. and Flandrois, J. P., 1995. Convenient model to describe the combined effects of temperature and pH on microbial growth, Applied and Environmental Microbiology, 61: 610-616], this paper focuses on the accurate estimation of its four parameters (T(min), T(opt), T(max) and micro(opt)) by applying the technique of optimal experiment design for parameter estimation (OED/PE). This secondary model describes the influence of temperature on the microbial specific growth rate from the minimum to the maximum temperature for growth. Dynamic temperature profiles are optimized within two temperature regions ([15 degrees C, 43 degrees C] and [15 degrees C, 45 degrees C]), focusing on the minimization of the parameter estimation (co)variance (D-optimal design). The optimal temperature profiles are implemented in a computer controlled bioreactor, and the CTMI parameters are identified from the resulting experimental data. Approximately equal CTMI parameter values were derived irrespective of the temperature region, except for T(max). The latter could only be estimated accurately from the optimal experiments within [15 degrees C, 45 degrees C]. This observation underlines the importance of selecting the upper temperature constraint for OED/PE as close as possible to the true T(max). Cardinal temperature estimates resulting from designs within [15 degrees C, 45 degrees C] correspond with values found in literature, are characterized by a small uncertainty error and yield a good result during validation. As compared to estimates from non-optimized dynamic experiments, more reliable CTMI parameter values were obtained from the optimal experiments within [15 degrees C, 45 degrees C]. PMID:18835500

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  17. Scaling and optimal synergy: Two principles determining microbial growth in complex media

    NASA Astrophysics Data System (ADS)

    Massucci, Francesco Alessandro; Guimerà, Roger; Nunes Amaral, Luís A.; Sales-Pardo, Marta

    2015-06-01

    High-throughput experimental techniques and bioinformatics tools make it possible to obtain reconstructions of the metabolism of microbial species. Combined with mathematical frameworks such as flux balance analysis, which assumes that nutrients are used so as to maximize growth, these reconstructions enable us to predict microbial growth. Although such predictions are generally accurate, these approaches do not give insights on how different nutrients are used to produce growth, and thus are difficult to generalize to new media or to different organisms. Here, we propose a systems-level phenomenological model of metabolism inspired by the virial expansion. Our model predicts biomass production given the nutrient uptakes and a reduced set of parameters, which can be easily determined experimentally. To validate our model, we test it against in silico simulations and experimental measurements of growth, and find good agreement. From a biological point of view, our model uncovers the impact that individual nutrients and the synergistic interaction between nutrient pairs have on growth, and suggests that we can understand the growth maximization principle as the optimization of nutrient synergies.

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

    SciTech Connect

    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

    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.

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

    PubMed Central

    2013-01-01

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

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

    PubMed Central

    2013-01-01

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

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

    PubMed

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

    2007-01-01

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

  2. Improving the efficiency of perovskite solar cells through optimization of the CH3NH3PbI3 film growth in solution process method

    NASA Astrophysics Data System (ADS)

    Zhao, Ying; Liu, Jian; Lu, Xinrong; Gao, Yandong; You, Xiaozeng; Xu, Xiangxing

    2015-12-01

    Perovskite-structured organic-inorganic materials such as CH3NH3PbI3 are attracting much interest in the scientific community because of their abilities to function as revolutionary light harvesters and charge transfer materials for solar cells. To achieve high power conversion efficiency (PCE), it is critical to optimize the perovskite film layer. This paper reports the temperature and concentration controls on the two-step solution process. A diffusion-controlled growth mechanism is proposed for this process in tuning the morphology and purity of the perovskite film, which are proven to be important factors contributing to the photovoltaic performance. The highest PCE of 11.92% is achieved with an optimized perovskite crystal size of ∼150 nm and an appropriate amount of residual PbI2. This study sheds light on the design and fabrication of highly efficient, low-cost, solution-processed perovskite solar cells.

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

    PubMed

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

    2013-01-01

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

  4. Thermal Preference of Juvenile Dover Sole (Solea solea) in Relation to Thermal Acclimation and Optimal Growth Temperature

    PubMed Central

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

    2013-01-01

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

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

    PubMed Central

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

    2012-01-01

    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. PMID:18302186

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

    NASA Technical Reports Server (NTRS)

    Hajela, P.

    1982-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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 δ < 0.025 at 100 kHz. The data demonstrate that BTO films grown on polycrystalline Ni substrates by PAD are promising in device applications.

  8. Optimizing the combined application of amendments to allow plant growth in a multielement-contaminated soil.

    PubMed

    Sevilla-Perea, A; Romero-Puertas, M C; Mingorance, M D

    2016-04-01

    This study was aimed to 1) properly understand the dynamics of toxic elements (Al, Fe, Mn, Cu, Pb, Zn and As) in a sulphide-mine soil after combined application of compost from urban sewage sludge (SVC) and bottom ashes from biomass combustion (BA) and to 2) optimize the combination of both amendments for vegetation growth. Soil was amended following a D-optimal design and the mixtures (15 in total) were incubated during 30 d. At the end of the incubation, the effects of amendments on the assessed variables as well as the process modelling were evaluated by Response Surface Methodology (RSM). The process modelling confirmed that quadratic models were adequate to explain the behaviour of the assessed variables (R(2) ≥ 0.94 and Q(2) ≥ 0.75). Both amendments significantly increased pH and electrical conductivity, while reduced metal extractability. A different behaviour of As respect to metals was observed and high doses of BA sharply increased its extractability. The optimization process indicated that adequate conditions for vegetation growth would be reached adding the soil with 6.8% of SVC and 3.1% of BA (dry weight). After amendments application the germination and root elongation of three energy crops were significantly increased while lipid peroxidation was decreased. Therefore, the combined application of SVC and BA to a contaminated soil could improve soil conditions and might be expected to have an advantage during plant growth. Moreover, the RSM could be a powerful technique for the assessment of combined amendment effects on soil properties and their effective application in multielement-contaminated soils. PMID:26807942

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Davidson, Zachary William

    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.

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

    PubMed

    Brewer, Gregory J; LeRoux, Peter D

    2007-07-01

    Glioblastoma is the most common primary brain tumor in adults from which about 15,000 patients die each year in the United States. Despite aggressive surgery, radiotherapy and chemotherapy, median survival remains only 1 year. Here we evaluate growth of primary human brain tumor cells in a defined nutrient culture medium (Neuregen) that was optimized for neuron regeneration. We hypothesized that Neuregen would inhibit tumor cell growth because of its ability to inhibit gliosis in rat brain. Tumor tissue was collected from 18 patients including 10 males and 8 females (mean age 60+/-12 years) who underwent craniotomy for newly diagnosed, histologically confirmed brain tumors. The tissue was shipped overnight in Hibernate transport medium. Tumor cells were isolated and plated in Neurobasal/serum or Neuregen on culture plastic. After 1 week, growth in Neuregen was significantly less in 9/10 glioblastoma multiforme cases, 5/5 meningioma cases and 3/3 cases of brain metastasis. Analysis of deficient formulations of Neuregen and formulations to which selected components were added back implicate no single active component. However, individual cases were sensitive to corticosterone, selenium, ethanolamine, fatty acids and/or antioxidants. Therefore, a defined culture medium that promotes neuron regeneration inhibits the growth of human primary glioblastoma, meningioma and metastatic tumor cells in culture. The possible in vivo efficacy of Neuregen for treatment of brain tumor resections remains to be determined. PMID:17537410

  12. Optimizing Production of Superconducting Bulk YBCO Crystals: Effects of Initial Temperature and Growth Time

    NASA Astrophysics Data System (ADS)

    Jolley, Erin; Shea, Connor; Hunting, Janet; Sullivan, M. C.

    We present our work on increasing both pinning force and critical temperature of bulk YBCO superconducting crystals. We optimized temperature profiles for growing bulk YBaCuO superconductors by varying (a) temperature and (b) growth time. We synthesize the precursor materials, superconducting Y1Ba2Cu3O7 (Y-123) and non-superconducting Y2Ba1Cu1O5 (Y-211), and mix the two in a 1:0.4 molar ratio before beginning melt textured growth. We heat the mixture to a temperature above the melting point of Y-123 but below the melting point of Y-211, where it is held until the Y-123 melts and the Y-211 impurities disperse in the mixture. The mixture is then quickly cooled to an initial temperature (a) near the peritectic point, and is then slowly cooled for 30-100 hours (b) to allow steady growth of large domain Y-123 crystals. We will discuss the effects of different initial temperatures near the peritectic point and growth times on the pinning force and critical temperature of these samples. This work was supported by NSF Grant DMR-1305637, and made use of the Cornell Center for Materials Research Shared Facilities which are supported through the NSF MRSEC program (Grant DMR-1120296).

  13. Super-optimal CO2 reduces wheat yield in growth chamber and greenhouse environments

    NASA Astrophysics Data System (ADS)

    Grotenhuis, T.; Reuveni, J.; Bugbee, B.

    1997-01-01

    Seven growth chamber trials (six replicate trials using 0.035, 0.12, and 0.25 % CO_2 in air and one trial using 0.12, 0.80, and 2.0% CO_2 in air) and three replicate greenhouse trials (0.035, 0.10, 0.18, 0.26, 0.50, and 1.0% CO_2 in air) compare the effects of super-optimal CO_2 on the seed yield, harvest index, and vegetative growth rate of wheat (Triticum aestivum L. cvs. USU-Apogee and Veery-10). Plants in the growth chamber trials were grown hydroponically under fluorescent lamps, while the greenhouse trials were grown under sunlight and high pressure sodium lamps and in soilless media. Plants in the greenhouse trials responded similarly to those in the growth chamber trials; maximum yields occurred near 0.10 and 0.12 % CO_2 and decreased significantly thereafter. This research indicates that the toxic effects of elevated CO_2 are not specific to only one environment and has important implications for the design of bio-regenerative life support systems in space, and for the future of terrestrial agriculture.

  14. Super-optimal CO2 reduces wheat yield in growth chamber and greenhouse environments.

    PubMed

    Grotenhuis, T; Reuveni, J; Bugbee, B

    1997-01-01

    Seven growth chamber trials (six replicate trials using 0.035, 0.12, and 0.25% CO2 in air and one trial using 0.12, 0.80, and 2.0% CO2 in air) and three replicate greenhouse trials (0.035, 0.10, 0.18, 0.26, 0.50, and 1.0% CO2 in air) compare the effects of super-optimal CO2 on the seed yield, harvest index, and vegetative growth rate of wheat (Triticum aestivum L. cvs. USU-Apogee and Veery-10). Plants in the growth chamber trials were grown hydroponically under fluorescent lamps, while the greenhouse trials were grown under sunlight and high pressure sodium lamps and in soilless media. Plants in the greenhouse trials responded similarly to those in the growth chamber trials; maximum yields occurred near 0.10 and 0.12% CO2 and decreased significantly thereafter. This research indicates that the toxic effects of elevated CO2 are not specific to only one environment and has important implications for the design of bio-regenerative life support systems in space, and for the future of terrestrial agriculture. PMID:11542567

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

    PubMed Central

    Witte, Todd N; Ginsberg, Allen L

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    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 μm 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.

  17. Assessing the Effects of a School-Wide Data-Based Decision-Making Intervention on Student Achievement Growth in Primary Schools

    ERIC Educational Resources Information Center

    van Geel, Marieke; Keuning, Trynke; Visscher, Adrie J.; Fox, Jean-Paul

    2016-01-01

    Despite growing international interest in the use of data to improve education, few studies examining the effects on student achievement are yet available. In the present study, the effects of a two-year data-based decision-making intervention on student achievement growth were investigated. Fifty-three primary schools participated in the project,…

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

    ERIC Educational Resources Information Center

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

    2006-01-01

    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…

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  20. Optimizing and real-time control of biofilm formation, growth and renewal in denitrifying biofilter.

    PubMed

    Liu, Xiuhong; Wang, Hongchen; Long, Feng; Qi, Lu; Fan, Haitao

    2016-06-01

    A pilot-scale denitrifying biofilter (DNBF) with a treatment capacity of 600m(3)/d was used to study real-time control of biofilm formation, removal and renewal. The results showed biofilm formation, growth and removal can be well controlled using on-line monitored turbidity. The status of filter layer condition can be well indicated by Turb break points on turbidity profile. There was a very good linear relationship between biofilm growth degree (Xbiof) and filter clogging degree (Cfilter) with R(2) higher than 0.99. Filter layer clogging coefficient (Yc) lower than 0.27 can be used to determine stable filter layer condition. Since variations of turbidity during backwash well fitted normal distribution with R(2) higher than 0.96, biofilm removal during backwash also can be well optimized by turbidity. Although biofilm structure and nirK-coding denitrifying communities using different carbon sources were much more different, DNBF was still successfully and stably optimized and real-time controlled via on-line turbidity. PMID:26994461

  1. Aconitase B is required for optimal growth of Xanthomonas campestris pv. vesicatoria in pepper plants.

    PubMed

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  3. Modelling and Optimization of Nannochloropsis and Chlorella Growth for Various Locations and Seasons

    NASA Astrophysics Data System (ADS)

    Gharagozloo, P. E.

    2014-12-01

    Efficient production of algal biofuels could reduce dependence on foreign oil providing domestic renewable energy. Algae-based biofuels are attractive for their large oil yield potential despite decreased land use and natural-resource requirements compared to terrestrial energy crops. Important factors controlling algal-lipid productivity include temperature, nutrient availability, salinity, pH, and the light-to-biomass conversion rate. Computational approaches allow for inexpensive predictions of algae-growth kinetics for various bioreactor sizes and geometries without multiple, expensive measurement systems. In this work, we parameterize our physics-based computational algae growth model for the marine Nannochloropsis oceanica and freshwater Chlorella species. We then compare modelling results with experiments conducted in identical raceway ponds at six geographical locations in the United States (Hawaii, California, Arizona, Ohio, Georgia, and Florida) and three seasons through the Algae Testbed Public Private Partnership - Unified Field Studies. Results show that the computational model effectively predicts algae growth in systems across varying environments and identifies the causes for reductions in algal productivities. The model is then used to identify improvements to the cultivation system to produce higher biomass yields. This model could be used to study the effects of scale-up including the effects of predation, depth-decay of light (light extinction), and optimized nutrient and CO2 delivery. As more multifactorial data are accumulated for a variety of algal strains, the model could be used to select appropriate algal species for various geographic and climatic locations and seasons. Applying the model facilitates optimization of pond designs based on location and season.

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

    PubMed

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

    2015-02-01

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

  5. Optimization of growth conditions for laboratory and field assessments using immobilized benthic diatoms.

    PubMed

    Vidal, Tânia; Marques, Catarina; Abrantes, Nelson; Pereira, Joana Luísa; Soares, Amadeu M V M; Gonçalves, Fernando

    2015-04-01

    The availability of rapid and effective methodologies for assessing lotic systems with microphytobenthos is still quite scarce. Hence, the primary goal of this study was to optimize the growth conditions of the sensitive and ubiquous benthic diatom Navicula libonensis for laboratorial and field assessments. The effect of different conditions of temperature, photoperiod, initial cell density, test duration and cell encapsulation into calcium alginate beads was evaluated in a first set of experiments. There was a slight increase in the growth of free and immobilized cells at 23 °C, at lower initial cell densities and at the shortest experimental period (6 days). Through all the conditions, the growth profiles of free versus immobilized were fairly variable. A second experimental trial involved the validation of selected conditions, applied to the ecotoxicological testing of N. libonensis to two reference chemicals-3,5-dichlorophenol and potassium dichromate. A similar response of free and immobilized cells was observed between exposures to spiked stream water and synthetic medium, and through the conditions tested. This outcome suggests that N. libonensis may potentially provide reliable responses under direct in situ exposures. PMID:25354432

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

    NASA Technical Reports Server (NTRS)

    Tiller, Michael M.

    1995-01-01

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

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

    ERIC Educational Resources Information Center

    Chiu, Pui Chi

    2012-01-01

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

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

    SciTech Connect

    Krishnan, Manoj Kumar; Nieplocha, Jarek

    2005-04-26

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

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

    NASA Technical Reports Server (NTRS)

    Tumin, Anatoli; Ashpis, David E.

    2003-01-01

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

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

    PubMed

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

    2014-10-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  13. Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification

    PubMed Central

    Lassnig, R.; Hollerer, M.; Striedinger, B.; Fian, A.; Stadlober, B.; Winkler, A.

    2015-01-01

    In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p++-silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3–4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact–channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility. PMID:26543442

  14. Advancement in optimization tactic achieved by newly developed chromatographic response function: application to LC separation of raloxifene and its impurities.

    PubMed

    Jančić-Stojanović, B; Rakić, T; Kostić, N; Vemić, A; Malenović, A; Ivanović, D; Medenica, M

    2011-09-15

    In this paper a new chromatographic response function (CRF) is designed and proposed for utilization in the optimization strategies. The function capability to represent the overall quality of a experimentally obtained chromatograms was compared to the other two objective functions and proved to give more accurate and reliable results. The new CRF has improved concept of separation and time term estimation. It reflects all important defects of the chromatogram such as the appearance of asymmetrical or overlapping peaks and prolonged elution time and allows the appropriate weighting of each of them. The LC separation of raloxifene and its four impurities was evaluated through the central composite design experimental plan choosing the new CRF to be the only output of the system. The function demonstrated the ability to judge the impact of the complex interactions of the selected chromatographic parameters (acetonitrile content in the mobile phase, sodium dodecyl sulfate concentration in the water phase, pH of the mobile phase and column temperature) on the mixture behavior and led to the determination of the optimal separation conditions. The newly developed CRF proved to have the advanced performances and it presents the important step forward in the optimization of the chromatographic separation. PMID:21807209

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

    NASA Astrophysics Data System (ADS)

    Miyauchi, T.; Machimura, T.

    2013-12-01

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

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

    PubMed Central

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

    2009-01-01

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

  17. Whole Genome Re-Sequencing Identifies a Quantitative Trait Locus Repressing Carbon Reserve Accumulation during Optimal Growth in Chlamydomonas reinhardtii.

    PubMed

    Goold, Hugh Douglas; Nguyen, Hoa Mai; Kong, Fantao; Beyly-Adriano, Audrey; Légeret, Bertrand; Billon, Emmanuelle; Cuiné, Stéphan; Beisson, Fred; Peltier, Gilles; Li-Beisson, Yonghua

    2016-01-01

    Microalgae have emerged as a promising source for biofuel production. Massive oil and starch accumulation in microalgae is possible, but occurs mostly when biomass growth is impaired. The molecular networks underlying the negative correlation between growth and reserve formation are not known. Thus isolation of strains capable of accumulating carbon reserves during optimal growth would be highly desirable. To this end, we screened an insertional mutant library of Chlamydomonas reinhardtii for alterations in oil content. A mutant accumulating five times more oil and twice more starch than wild-type during optimal growth was isolated and named constitutive oil accumulator 1 (coa1). Growth in photobioreactors under highly controlled conditions revealed that the increase in oil and starch content in coa1 was dependent on light intensity. Genetic analysis and DNA hybridization pointed to a single insertional event responsible for the phenotype. Whole genome re-sequencing identified in coa1 a >200 kb deletion on chromosome 14 containing 41 genes. This study demonstrates that, 1), the generation of algal strains accumulating higher reserve amount without compromising biomass accumulation is feasible; 2), light is an important parameter in phenotypic analysis; and 3), a chromosomal region (Quantitative Trait Locus) acts as suppressor of carbon reserve accumulation during optimal growth. PMID:27141848

  18. Whole Genome Re-Sequencing Identifies a Quantitative Trait Locus Repressing Carbon Reserve Accumulation during Optimal Growth in Chlamydomonas reinhardtii

    PubMed Central

    Goold, Hugh Douglas; Nguyen, Hoa Mai; Kong, Fantao; Beyly-Adriano, Audrey; Légeret, Bertrand; Billon, Emmanuelle; Cuiné, Stéphan; Beisson, Fred; Peltier, Gilles; Li-Beisson, Yonghua

    2016-01-01

    Microalgae have emerged as a promising source for biofuel production. Massive oil and starch accumulation in microalgae is possible, but occurs mostly when biomass growth is impaired. The molecular networks underlying the negative correlation between growth and reserve formation are not known. Thus isolation of strains capable of accumulating carbon reserves during optimal growth would be highly desirable. To this end, we screened an insertional mutant library of Chlamydomonas reinhardtii for alterations in oil content. A mutant accumulating five times more oil and twice more starch than wild-type during optimal growth was isolated and named constitutive oil accumulator 1 (coa1). Growth in photobioreactors under highly controlled conditions revealed that the increase in oil and starch content in coa1 was dependent on light intensity. Genetic analysis and DNA hybridization pointed to a single insertional event responsible for the phenotype. Whole genome re-sequencing identified in coa1 a >200 kb deletion on chromosome 14 containing 41 genes. This study demonstrates that, 1), the generation of algal strains accumulating higher reserve amount without compromising biomass accumulation is feasible; 2), light is an important parameter in phenotypic analysis; and 3), a chromosomal region (Quantitative Trait Locus) acts as suppressor of carbon reserve accumulation during optimal growth. PMID:27141848

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

    PubMed

    Leu, Jyh-Yih; Lin, Yen-Hui

    2013-01-01

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

  20. SU-E-T-387: Achieving Optimal Patient Setup Imaging and Treatment Workflow Configurations in Multi-Room Proton Centers

    SciTech Connect

    Zhang, H; Prado, K; Langen, K; Yi, B; Mehta, M; Regine, W; D'Souza, W

    2014-06-01

    Purpose: To simulate patient flow in proton treatment center under uncertainty and to explore the feasibility of treatment preparation rooms to improve patient throughput and cyclotron utilization. Methods: Three center layout scenarios were modeled: (S1: In-Tx room imaging) patient setup and imaging (planar/volumetric) performed in treatment room, (S2: Patient setup in preparation room) each treatment room was assigned with preparation room(s) that was equipped with lasers only for patient setup and gross patient alignment, and (S3: Patient setup and imaging in preparation room) preparation room(s) was equipped with laser and volumetric imaging for patient setup, gross and fine patient alignment. A 'snap' imaging was performed in treatment room. For each scenario, the number of treatment rooms and the number of preparation rooms serving each treatment room were varied. We examined our results (average of 100 16-hour (two shifts) working days) by evaluating patient throughput and cyclotron utilization. Results: When the number of treatment rooms increased ([from, to]) [1, 5], daily patient throughput increased [32, 161], [29, 184] and [27, 184] and cyclotron utilization increased [13%, 85%], [12%, 98%], and [11%, 98%] for scenarios S1, S2 and S3 respectively. However, both measures plateaued after 4 rooms. With the preparation rooms, the throughput and the cyclotron utilization increased by 14% and 15%, respectively. Three preparation rooms were optimal to serve 1-3 treatment rooms and two preparation rooms were optimal to serve 4 or 5 treatment rooms. Conclusion: Patient preparation rooms for patient setup may increase throughput and decrease the need for additional treatment rooms (cost effective). Optimal number of preparation rooms serving each gantry room varies as a function of treatment rooms and patient setup scenarios. A 5th treatment room may not be justified by throughput or utilization.

  1. 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

    Baldridge, Mary Caufield

    2010-01-01

    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…

  2. 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

    Guglielmi, R. Sergio

    2008-01-01

    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…

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

    PubMed Central

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

    2013-01-01

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

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

    ERIC Educational Resources Information Center

    Warner, Darlene Ovyn

    2012-01-01

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

  5. Low Trap Density in InAs/High-k Nanowire Gate Stacks with Optimized Growth and Doping Conditions.

    PubMed

    Wu, Jun; Babadi, Aein Shiri; Jacobsson, Daniel; Colvin, Jovana; Yngman, Sofie; Timm, Rainer; Lind, Erik; Wernersson, Lars-Erik

    2016-04-13

    In this paper, we correlate the growth of InAs nanowires with the detailed interface trap density (Dit) profile of the vertical wrap-gated InAs/high-k nanowire semiconductor-dielectric gate stack. We also perform the first detailed characterization and optimization of the influence of the in situ doping supplied during the nanowire epitaxial growth on the sequential transistor gate stack quality. Results show that the intrinsic nanowire channels have a significant reduction in Dit as compared to planar references. It is also found that introducing tetraethyltin (TESn) doping during nanowire growth severely degrades the Dit profile. By adopting a high temperature, low V/III ratio tailored growth scheme, the influence of doping is minimized. Finally, characterization using a unique frequency behavior of the nanowire capacitance-voltage (C-V) characteristics reveals a change of the dopant incorporation mechanism as the growth condition is changed. PMID:26978479

  6. Maximizing and Optimizing the Large Scale Deployment of Renewable Energy: Achieving the U.S. Government's Goal of 20% by 2030

    NASA Astrophysics Data System (ADS)

    Alliss, R.; Apling, D.; Kiley, H.; Mason, M.

    2011-12-01

    The United States Government has an ambitious goal of growing renewable energy from 1% to 20% by 2030. Two key challenges exist in order to realize this target: Creating system-level approaches to overall generation capacity expansion and integration, including difficult policy changes, and addressing the variability issues of wind and solar generation. These challenges are addressed using MORE Power (Maximizing and Optimizing Renewable Energy), a system level planning tool designed to optimize the placement of wind and solar sites to maximize high quality, useable power. This planning tool uses historical, high resolution, measurements of wind and solar parameters along with a unique, non-linear, optimization algorithm to optimize the placement of sites given a set of user specified input parameters. MORE Power is quantifying the real value of transmission as an enabler to aggregate diverse variable resources which in turn is incentivizing transmission developers to expand the grid. In addition, the issue of grid stability becomes even more critical as larger deployment of renewable resources come online. MORE Power is identifying the benefits of larger balancing areas as an enabler for greater stability and therefore a reduced need to keep transmission capacity in reserve. In the end, by addressing and minimizing the impacts of the natural variability of wind and solar, a reduction in price volatility results which favorably impacts the consumer. This presentation will show examples of how MORE Power is being used to address the variability issue of renewables in order to achieve the 20% deployment target by 2030.

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

    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.

  8. A comprehensive siRNA screen for kinases that suppress macroautophagy in optimal growth conditions.

    PubMed

    Szyniarowski, Piotr; Corcelle-Termeau, Elisabeth; Farkas, Thomas; Høyer-Hansen, Maria; Nylandsted, Jesper; Kallunki, Tuula; Jäättelä, Marja

    2011-08-01

    Macroautophagy is a catabolic process that maintains cellular homeostasis and protects cells against various external stresses including starvation. Except for the identification of the Akt-mTORC1 pathway as a major negative regulator, little is known about signaling networks that control macroautophagy under optimal growth conditions. Therefore, we screened a human kinome siRNA library for siRNAs that increase the number of autophagosomes in normally growing MCF-7 human breast carcinoma cells, and identified 10 kinases as regulators of constitutive macroautophagy. Further analysis of these kinases with respect to the autophagic flux, kinase signaling and endolysosomal function identified WNK2 as a positive regulator of autophagosome maturation and nine others as macroautophagy inhibitors. The depletion of MK2, PACSIN1, DAPK2, CDKL3 and SCYL1 functioned upstream of Akt-mTORC1 pathway, whereas CSNK1A1, BUB1, PKLR and NEK4 suppressed autophagosome formation downstream or independent of mTORC1. Importantly, all identified kinases except for BUB1 regulated macroautophagy also in immortalized MCF-10A breast epithelial cells. The kinases identified here shed light to the complex regulation of macroautophagy and open new possibilities for its pharmacological manipulation. PMID:21508686

  9. Noncovalent Mutant Selective Epidermal Growth Factor Receptor Inhibitors: A Lead Optimization Case Study.

    PubMed

    Heald, Robert; Bowman, Krista K; Bryan, Marian C; Burdick, Daniel; Chan, Bryan; Chan, Emily; Chen, Yuan; Clausen, Saundra; Dominguez-Fernandez, Belen; Eigenbrot, Charles; Elliott, Richard; Hanan, Emily J; Jackson, Philip; Knight, Jamie; La, Hank; Lainchbury, Michael; Malek, Shiva; Mann, Sam; Merchant, Mark; Mortara, Kyle; Purkey, Hans; Schaefer, Gabriele; Schmidt, Stephen; Seward, Eileen; Sideris, Steve; Shao, Lily; Wang, Shumei; Yeap, Kuen; Yen, Ivana; Yu, Christine; Heffron, Timothy P

    2015-11-25

    Because of their increased activity against activating mutants, first-generation epidermal growth factor receptor (EGFR) kinase inhibitors have had remarkable success in treating non-small-cell lung cancer (NSCLC) patients, but acquired resistance, through a secondary mutation of the gatekeeper residue, means that clinical responses only last for 8-14 months. Addressing this unmet medical need requires agents that can target both of the most common double mutants: T790M/L858R (TMLR) and T790M/del(746-750) (TMdel). Herein we describe how a noncovalent double mutant selective lead compound was optimized using a strategy focused on the structure-guided increase in potency without added lipophilicity or reduction of three-dimensional character. Following successive rounds of design and synthesis it was discovered that cis-fluoro substitution on 4-hydroxy- and 4-methoxypiperidinyl groups provided synergistic, substantial, and specific potency gain through direct interaction with the enzyme and/or effects on the proximal ligand oxygen atom. Further development of the fluorohydroxypiperidine series resulted in the identification of a pair of diastereomers that showed 50-fold enzyme and cell based selectivity for T790M mutants over wild-type EGFR (wtEGFR) in vitro and pathway knock-down in an in vivo xenograft model. PMID:26455919

  10. Optimization of fluorine content in TFA-MOD precursor solutions for YBCO film growth

    NASA Astrophysics Data System (ADS)

    Jin, L. H.; Li, C. S.; Feng, J. Q.; Yu, Z. M.; Wang, Y.; Lei, L.; Zhao, G. Y.; Sulpice, A.; Zhang, P. X.

    2016-01-01

    Several low fluorine solutions containing different contents of fluorine were prepared by a chemical process. The fluorine contents in these solutions with respect to the conventional all-trifluoroacetate solution were calculated as 0%, 7.7%, 15.4%, 23.1%, 30.8%, 38.5% and 53.8%. YBa2Cu3O7-x (YBCO) films were deposited on LaAlO3 and CeO2/MgO/Al2O3/Hastelloy substrates using these low fluorine solutions. The phase formation, texture and microstructure of the YBCO films were characterized by x-ray diffraction and scanning electron microscopy. The decomposition mechanism of the low fluorine solution was also discussed. The results indicate that the ratio of F/Ba and the carbon content in decomposed powders could be controlled by adjusting the fluorine content in the precursor solutions. Fluorine had a great influence on the phase transformation, nucleation and growth of YBCO film during the crystallization process. The optimization of fluorine content was in the range of 15.4%-23.1%, which contributed to the good texture, homogeneous microstructure and high J c value of the YBCO crystallized films.

  11. High uniform growth of 4-inch GaN wafer via flow field optimization by HVPE

    NASA Astrophysics Data System (ADS)

    Cheng, Yutian; Liu, Peng; Wu, Jiejun; Xiang, Yong; Chen, Xinjuan; Ji, Cheng; Yu, Tongjun; Zhang, Guoyi

    2016-07-01

    The uniformity of flow field inner the reactor plays a crucial role for hydride vapor phase epitaxy (HVPE) crystal growth and its more important for large scale substrate. A new nozzle structure was designed by adding a push and dilution (PD) gas pipe in the center of gas channels for a 4-inch HVPE (PD-HVPE) system. Experimental results showed that the thickness inhomogeneity of 46 μm 4-inch GaN layer could reach ±1.8% by optimizing PD gas, greatly improved from ±14% grown with conventional nozzle. The simulations of the internal flow field were consistent with our experiment, and the enhancement in uniformity should be attributed to the redistribution of GaCl and NH3 upon the wafer induced by PD pipe. The full width at half maximum (FWHM) of X-ray diffraction rocking curves for the 4-inch GaN film were about 224 and 200 arcsec for (002) and (102) reflection. The dislocation density of as-grown GaN was about 6.4×107 cm-2.

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

    SciTech Connect

    Wayne Penrod; David Moyeda

    2003-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  14. Optimal Duration of Pegylated Interferon Plus Ribavirin Therapy for Chronic Hepatitis C Genotype 3 Patients who do not Achieve Rapid Virological Response

    PubMed Central

    Sood, Ajit; Midha, Vandana; Goyal, Omesh

    2015-01-01

    Background/Objectives Chronic hepatitis C (CHC) genotype-3 (G-3) patients treated with standard 24-week pegylated interferon plus ribavirin(PEG-RBV) therapy achieve sustained virological response(SVR) rate of 69–82%. Patients who do not achieve rapid virological response(RVR) have lower SVR rate. Data regarding optimal management of this subgroup is scarce. We aimed to determine the most appropriate treatment duration in CHC G-3 patients who do not achieve RVR. Methods Treatment naïve CHC G-3 patients treated with PEG-RBV therapy were included in this retrospective analysis. Patients with cirrhosis were excluded. RVR was assessed in all patients beyond the year 2007. RVR non-achievers were advised extended treatment beyond 24 weeks. Results Of the total 685 patients started on treatment, 646 completed treatment (mean age 39.1 ± 12 years, 68.3% males). In the pre-‘RVR assessment’ period (2004–2006), SVR with standard 24 week therapy was 72.3% (112/155). In post-‘RVR assessment’ period (2007–2013), 75.8% (402/530) patients achieved RVR; and 91.5% (368/402) of these achieved SVR with standard 24 weeks therapy. Among RVR non-achievers (n = 128), 51 patients opted for extended 36 week therapy, 12 for 48 week therapy, while 65 stopped therapy at 24 weeks. Choice of treatment duration was dependent entirely on the affordability of the patient. SVR with extended therapy (36/48 weeks) was significantly higher than standard 24 week therapy in RVR non-achievers (82.5% vs. 52.3%; P = 0.003). However, SVR rate in 36 week group was not significantly different from 48 week group (84.3% vs. 75%; P = 0.425]. On multivariate analysis, duration of treatment (36/48 week vs. 24 week; P < 0.001) was significantly associated with SVR. Conclusions SVR rates in CHC G-3 patients treated with PEG-RBV in northern India were comparable to western data. Standard 24 week therapy is adequate for RVR-achievers. However, in RVR non-achievers, extended 36 week therapy significantly improves SVR, while further extension to 48 week does not provide any additional advantage. PMID:25941428

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

    PubMed Central

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

    2015-01-01

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

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

    EPA Science Inventory

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

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

    SciTech Connect

    O, Se Young; Lee, Chan-Gyu; Shapiro, Alexander J.; Egelhoff, William F. Jr.; Mallett, Jonathan; Pong, Philip W. T.; Vaudin, Mark D.; Ruglovsky, Jennifer L.

    2008-04-01

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

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

    PubMed Central

    Wahl, Anna-Sophia; Schwab, Martin E.

    2014-01-01

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

  19. Optimization of Methanotrophic Growth and Production of Poly(3-Hydroxybutyrate) in a High-Throughput Microbioreactor System

    PubMed Central

    Criddle, Craig S.

    2015-01-01

    Production of poly(3-hydroxybutyrate) (P3HB) from methane has economic and environmental advantages over production by agricultural feedstock. Identification of high-productivity strains and optimal growth conditions is critical to efficient conversion of methane to polymer. Current culture conditions, including serum bottles, shake flasks, and agar plates, are labor-intensive and therefore insufficient for systematic screening and isolation. Gas chromatography, the standard method for analysis of P3HB content in bacterial biomass, is also incompatible with high-throughput screening. Growth in aerated microtiter plates coupled with a 96-well Nile red flow-cytometric assay creates an integrated microbioreactor system for high-throughput growth and analysis of P3HB-producing methanotrophic cultures, eliminating the need for individual manipulation of experimental replicates. This system was tested in practice to conduct medium optimization for P3HB production in pure cultures of Methylocystis parvus OBBP. Optimization gave insight into unexpected interactions: for example, low calcium concentrations significantly enhanced P3HB production under nitrogen-limited conditions. Optimization of calcium and copper concentrations in the growth medium increased final P3HB content from 18.1% to 49.4% and P3HB concentration from 0.69 g/liter to 3.43 g/liter while reducing doubling time from 10.6 h to 8.6 h. The ability to culture and analyze thousands of replicates with high mass transfer in completely mixed culture promises to streamline medium optimization and allow the detection and isolation of highly productive strains. Applications for this system are numerous, encompassing analysis of biofuels and other lipid inclusions, as well as analysis of heterotrophic and photosynthetic systems. PMID:25956771

  20. Optimization of growth and bacteriocin production by Lactobacillus sakei subsp. sakei2a

    PubMed Central

    Malheiros, Patrcia S.; SantAnna, Voltaire; Todorov, Svetoslav D.; Franco, Bernadette D.G.M.

    2015-01-01

    Lactobacillus sakei subsp. sakei 2a is a bacteriocinogenic lactic acid bacterium isolated from Brazilian pork sausage, capable of inhibiting the growth of microbial pathogens, mainly Listeria monocytogenes. In order to optimize bacteriocin production for industrial applications, this study evaluated the effect of supplementation of MRS broth with glucose, Tween 20, Tween 80, sodium citrate, potassium chloride and cysteine, and effect of the initial pH and temperature of incubation of the medium on production of bacteriocins by L. sakei 2a. Adding glucose and Tween 20 to the medium, an initial pH of 5.0 or 5.5, and incubation temperatures of 25 C or 30 C resulted to the highest bacteriocin yields. Thus, a 24 factorial design with the four variables was performed, and statistical analysis showed that it was an adequate model (R 2 = 0.8296). In the studied range, the four parameters significantly influenced bacteriocin production, with the maximum yield produced at an initial pH between 5.5 and 7.0, a temperature between 25 and 30 C and supplementation of the MRS broth with glucose from 3.25 to 6.0 g L?1 and Tween 20 from 0.575 to 1.15% (v/v). Response Surface Methodology analysis indicated that the highest bacteriocin production (12800 AU mL?1) occurred in the MRS broth supplemented with 5.5 g L?1 glucose and 1.05% Tween 20 at an initial pH of 6.28 and an incubation temperature of 25 C. The amount of bacteriocin produced in commercial MRS broths under the same conditions was only 5600AU mL?1. PMID:26413066

  1. Optimization of growth and bacteriocin production by Lactobacillus sakei subsp. sakei2a.

    PubMed

    Malheiros, Patrícia S; Sant'Anna, Voltaire; Todorov, Svetoslav D; Franco, Bernadette D G M

    2015-01-01

    Lactobacillus sakei subsp. sakei 2a is a bacteriocinogenic lactic acid bacterium isolated from Brazilian pork sausage, capable of inhibiting the growth of microbial pathogens, mainly Listeria monocytogenes. In order to optimize bacteriocin production for industrial applications, this study evaluated the effect of supplementation of MRS broth with glucose, Tween 20, Tween 80, sodium citrate, potassium chloride and cysteine, and effect of the initial pH and temperature of incubation of the medium on production of bacteriocins by L. sakei 2a. Adding glucose and Tween 20 to the medium, an initial pH of 5.0 or 5.5, and incubation temperatures of 25 °C or 30 °C resulted to the highest bacteriocin yields. Thus, a 2(4) factorial design with the four variables was performed, and statistical analysis showed that it was an adequate model (R (2) = 0.8296). In the studied range, the four parameters significantly influenced bacteriocin production, with the maximum yield produced at an initial pH between 5.5 and 7.0, a temperature between 25 and 30 °C and supplementation of the MRS broth with glucose from 3.25 to 6.0 g L(-1) and Tween 20 from 0.575 to 1.15% (v/v). Response Surface Methodology analysis indicated that the highest bacteriocin production (12800 AU mL(-1)) occurred in the MRS broth supplemented with 5.5 g L(-1) glucose and 1.05% Tween 20 at an initial pH of 6.28 and an incubation temperature of 25 °C. The amount of bacteriocin produced in commercial MRS broths under the same conditions was only 5600AU mL(-1). PMID:26413066

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

    SciTech Connect

    Wayne Penrod; David Moyeda

    2003-04-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Evidence of a Differential Effect of Ability Grouping on the Reading Achievement Growth of Language-Minority Hispanics

    ERIC Educational Resources Information Center

    Robinson, Joseph P.

    2008-01-01

    Ability grouping is sometimes thought to exacerbate inequality by increasing achievement gaps; however, ability grouping may in fact benefit a fast growing and often marginalized student population: children from non-English-speaking home environments. The level-appropriate, small-group instruction received in reading ability groups may be…

  5. Growth in Precursor and Reading-Related Skills: Do Low-Achieving and IQ-Discrepant Readers Develop Differently?

    ERIC Educational Resources Information Center

    O'Malley, Kimberly J.; Francis, David J.; Foorman, Barbara R.; Fletcher, Jack M.; Swank, Paul R.

    2002-01-01

    Poor readers who met low achievement and IQ-discrepancy definitions of reading disability (n=54) were compared with non-impaired readers (n=325) on development of eight precursor and reading-related skills. Results indicate no evidence for differences between the two groups of poor readers in the development on the eight skills, with three…

  6. Direct and Indirect Longitudinal Effects of Parental Involvement on Student Achievement: Second-Order Latent Growth Modeling Across Ethnic Groups

    ERIC Educational Resources Information Center

    Hong, Sehee; Ho, Hsiu-Zu

    2005-01-01

    The present study on the influence of parental involvement on students' academic achievement overcame limitations in current research by including simultaneous considerations of multidimensional, longitudinal, mediational, and ethnic factors. Results indicated (a) significant ethnic differences in the direct effects of parental involvement on…

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

    PubMed

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

    2014-07-01

    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

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

    PubMed

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

    2014-05-01

    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

  9. [Optimized expression, preparation of human papillomavirus 16 L2E7 fusion protein and its inhibitory effect on tumor growth in mice].

    PubMed

    Jiang, Yunshui; Li, Jianbo; Gao, Meng; Ren, Jiao; Jin, Sufeng; Chen, Gang; Wu, Jie; Zhuang, Fangcheng; Tian, Houwen

    2015-04-01

    HPV16 L2E7 is a fusion protein used for therapeutical vaccine targeting HPV virus. To increase its expression in Escherichia coli, we optimized the codon usage of HPV16 l2e7 gene based on its codon usage bias. The optimized gene of HPV16 sl2e7 was cloned into three different vectors: pGEX-5X-1, pQE30, ET41a, and expressed in JM109, JM109 (DE3) and BL21 (DE3) lines separately. A high expression line was selected with pET41a vector in BL21 (DE3) cells. After optimization of the growth condition, including inoculation amount, IPTG concentration, induction time and temperature, the expression level of HPV16 L2E7 was increased from less than 10% to about 28% of total protein. HPV16 L2E7 protein was then purified from 15 L culture by means of SP Sepharose Fast Flow, Q Sepharose Fast Flow and Superdex 200 pg. After renaturing, HPV16 L2E7 protein with ≥ 95% purity was achieved, which was confirmed via SDS-PAGE gel and Western blotting. The combined use of purified HPV16 L2E7 and CpG helper has shown clear inhibition of tumor growth in mice injected with tumor cells, with six out of eight mice shown no sign of tumor. This study lays a solid foundation for a new pipeline of large-scale vaccine production. PMID:26380413

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

    NASA Astrophysics Data System (ADS)

    Bess, John Darrell

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

  11. 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)

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

    2013-12-01

    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.

  12. Experimental determination of dependence of vertical growth rate on surface supersaturation in GaAs(001) microchannel epitaxy and growth optimization

    NASA Astrophysics Data System (ADS)

    Tomita, Masafumi; Mizuno, Yosuke; Takakura, Hiroyuki; Kambayashi, Daisuke; Naritsuka, Shigeya; Maruyama, Takahiro

    2016-04-01

    Surface supersaturation in microchannel epitaxy (MCE) by liquid-phase epitaxy is a key parameter to control the width-to-thickness ratio (aspect ratio), which determines the dimensions of the dislocation-free area. The interstep distance of a spiral step at a screw-dislocation and curve-fitting of screw-like steps at stacking faults (SFs) are employed to estimate the surface supersaturation during MCE. The dependence of the vertical growth rate on the surface supersaturation was experimentally studied in GaAs(001) MCE. As a result, 2D nucleation at SFs was determined to act as a strong step source, which is stronger than a typical spiral step at a screw-dislocation over a wide range of surface supersaturation. Precise control of the surface supersaturation is important to optimize the growth conditions for MCE. An MCE layer with a large aspect ratio can thus be reproducibly obtained using appropriately controlled surface supersaturation.

  13. Optimal error growth of South Asian monsoon forecast associated with the uncertainties in the sea surface temperature

    NASA Astrophysics Data System (ADS)

    Islam, Siraj Ul; Tang, Youmin; Jackson, Peter L.

    2016-03-01

    A recently developed method of climatic relevant singular vectors (CSVs) is applied to an atmospheric general circulation model (CAM4) to investigate the optimal error growth of the South Asian monsoon (SAM) seasonal prediction due to uncertainties in initial conditions of the sea surface temperature (SST). Emphasis is placed on the investigation of the optimal error growth of SAM seasonal forecast due to the SST uncertainties in the Indian and the equatorial Pacific Oceans. It is found that the uncertainties in the Indian Ocean can result in much larger error growth of SAM seasonal prediction than those in equatorial Pacific Ocean. Most of the CSV patterns over the Indian Ocean resembled a dipole-like structure with opposite signs spanning the northern and southern Indian Ocean. It is seen that the CSVs error growth rate changes significantly depending on the initial states whereas the CSVs patterns are insensitive to the initial conditions. The CSV patterns and error growth rates, calculated using CAM4, are also compared against those using coupled model CCSM4, indicating that the CSVs patterns from CAM4 are similar to those from CCSM4 coupled model while the error growth rate is lower in CAM4 than in CCSM4. Ensemble summer hindcasts, for the period from 2000 to 2009 over Indian Ocean, are constructed by the CSVs. For the purpose of comparison, ensemble forecasts constructed by the time lag ensemble (TLE) method are also conducted. It is found that the ensemble mean prediction by CSVs has a better skill than both the prediction by TLE and by the control run, in particular for predictions longer than 3 months, indicating the merit of CSV for SAM ensemble forecast.

  14. Optimal error growth of South Asian monsoon forecast associated with the uncertainties in the sea surface temperature

    NASA Astrophysics Data System (ADS)

    Islam, Siraj Ul; Tang, Youmin; Jackson, Peter L.

    2015-06-01

    A recently developed method of climatic relevant singular vectors (CSVs) is applied to an atmospheric general circulation model (CAM4) to investigate the optimal error growth of the South Asian monsoon (SAM) seasonal prediction due to uncertainties in initial conditions of the sea surface temperature (SST). Emphasis is placed on the investigation of the optimal error growth of SAM seasonal forecast due to the SST uncertainties in the Indian and the equatorial Pacific Oceans. It is found that the uncertainties in the Indian Ocean can result in much larger error growth of SAM seasonal prediction than those in equatorial Pacific Ocean. Most of the CSV patterns over the Indian Ocean resembled a dipole-like structure with opposite signs spanning the northern and southern Indian Ocean. It is seen that the CSVs error growth rate changes significantly depending on the initial states whereas the CSVs patterns are insensitive to the initial conditions. The CSV patterns and error growth rates, calculated using CAM4, are also compared against those using coupled model CCSM4, indicating that the CSVs patterns from CAM4 are similar to those from CCSM4 coupled model while the error growth rate is lower in CAM4 than in CCSM4. Ensemble summer hindcasts, for the period from 2000 to 2009 over Indian Ocean, are constructed by the CSVs. For the purpose of comparison, ensemble forecasts constructed by the time lag ensemble (TLE) method are also conducted. It is found that the ensemble mean prediction by CSVs has a better skill than both the prediction by TLE and by the control run, in particular for predictions longer than 3 months, indicating the merit of CSV for SAM ensemble forecast.

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

    PubMed

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

    2012-04-11

    By correlating the effects of substrate temperature, oxygen pressure and laser energy on the electrical and microstructural properties of Ag-doped ZnO films grown on a sapphire (0001) substrate, p-type conductivity is achieved under various substrate temperatures in the wide range of 250-750?C. All of the samples were deposited by pulsed-laser deposition under various designed conditions. Hall measurements indicate that the best conductivity is achieved in Ag-ZnO films under a substrate temperature of 500?C, a partial oxygen pressure of 250-300mTorr and laser energy between 330 and 345mJ. The hole-carrier concentration is 2.29נ10(18)cm(-3), the resistivity is 0.9?cm and the mobility is 3.03cm(2)V(-1)s(-1). Transmission-electron microscopy (TEM) studies on the p-type films reveal similar microstructural properties to one another, but different properties to that of the n-type films deposited at the same temperatures with different deposition parameters. PMID:22417979

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

    SciTech Connect

    Wayne Penrod

    2006-12-31

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

  17. Hype, harmony and human factors: applying user-centered design to achieve sustainable telehealth program adoption and growth.

    PubMed

    Rossos, P G; St-Cyr, O; Purdy, B; Toenjes, C; Masino, C; Chmelnitsky, D

    2015-01-01

    Despite decades of international experience with the use of information and communication technologies in healthcare delivery, widespread telehealth adoption remains limited and progress slow. Escalating health system challenges related to access, cost and quality currently coincide with rapid advancement of affordable and reliable internet based communication technologies creating unprecedented opportunities and incentives for telehealth. In this paper, we will describe how Human Factors Engineering (HFE) and user-centric elements have been incorporated into the establishment of telehealth within a large academic medical center to increase acceptance and sustainability. Through examples and lessons learned we wish to increase awareness of HFE and its importance in the successful implementation, innovation and growth of telehealth programs. PMID:25980714

  18. Planned Missing Designs to Optimize the Efficiency of Latent Growth Parameter Estimates

    ERIC Educational Resources Information Center

    Rhemtulla, Mijke; Jia, Fan; Wu, Wei; Little, Todd D.

    2014-01-01

    We examine the performance of planned missing (PM) designs for correlated latent growth curve models. Using simulated data from a model where latent growth curves are fitted to two constructs over five time points, we apply three kinds of planned missingness. The first is item-level planned missingness using a three-form design at each wave such

  19. Planned Missing Designs to Optimize the Efficiency of Latent Growth Parameter Estimates

    ERIC Educational Resources Information Center

    Rhemtulla, Mijke; Jia, Fan; Wu, Wei; Little, Todd D.

    2014-01-01

    We examine the performance of planned missing (PM) designs for correlated latent growth curve models. Using simulated data from a model where latent growth curves are fitted to two constructs over five time points, we apply three kinds of planned missingness. The first is item-level planned missingness using a three-form design at each wave such…

  20. Optimization of production of recombinant human growth hormone in Escherichia coli

    PubMed Central

    Rezaei, Marzieh; Zarkesh-Esfahani, Sayyed H.

    2012-01-01

    Background: Human growth hormone (hGH) is a single-chain polypeptide that participates in a wide range of biological functions such as metabolism of proteins, carbohydrates and lipids as well as in growth, development and immunity. Growth hormone deficiency in human occurs both in children and adults. The routine treatment for this condition is administration of recombinant human growth hormone (rhGH) made by prokaryotes. Since nonglycosylated human growth hormone is a biologically active protein, prokaryotic expression systems are preferred for its production. Materials and Methods: Different strains of E.coli were transformed by plasmid containing human growth hormone gene and cultured in different conditions. After induction by IPTG, recombinant human growth hormone production was assessed using ELISA, dot blotting and western blotting techniques. Results: High levels of rhGH were produced using E.coli prokaryotic protein production system. Conclusion: This simple and cost effective production process could be recruited for large scale production of rhGH. PMID:23798931

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

    SciTech Connect

    David Shropshire

    2009-09-01

    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.

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

    USGS Publications Warehouse

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

    2006-01-01

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

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

    SciTech Connect

    Jeganathan, K.; Shimizu, M.

    2014-09-15

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

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

    NASA Astrophysics Data System (ADS)

    Jeganathan, K.; Shimizu, M.

    2014-09-01

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

  5. Modeling and optimization of the growth of polycrystalline silicon films by thermal decomposition of silane

    NASA Astrophysics Data System (ADS)

    Peev, G.; Zambov, L.; Yanakiev, Y.

    1990-11-01

    A mathematical model for deposition of polysilicon films on silicon wafers in a horizontal tube reactor by thermal decomposition of silane at low pressure is proposed. The influence of temperature, pressure and gas flow rate on the film thickness uniformity is studied experimentally and by the model. An optimization criterion accounting for the energy and material consumption is defined. The limits of the technological factor variations allowed are discussed and the optimization criterion values within these limits are calculated. The analysis presented, demonstrating the significance of the chosen factors for the production cost-price is of great practical importance.

  6. Analysis of environmental stress factors using an artificial growth system and plant fitness optimization.

    PubMed

    Lee, Meonghun; Yoe, Hyun

    2015-01-01

    The environment promotes evolution. Evolutionary processes represent environmental adaptations over long time scales; evolution of crop genomes is not inducible within the relatively short time span of a human generation. Extreme environmental conditions can accelerate evolution, but such conditions are often stress inducing and disruptive. Artificial growth systems can be used to induce and select genomic variation by changing external environmental conditions, thus, accelerating evolution. By using cloud computing and big-data analysis, we analyzed environmental stress factors for Pleurotus ostreatus by assessing, evaluating, and predicting information of the growth environment. Through the indexing of environmental stress, the growth environment can be precisely controlled and developed into a technology for improving crop quality and production. PMID:25874206

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

    PubMed Central

    Lee, Meonghun; Yoe, Hyun

    2015-01-01

    The environment promotes evolution. Evolutionary processes represent environmental adaptations over long time scales; evolution of crop genomes is not inducible within the relatively short time span of a human generation. Extreme environmental conditions can accelerate evolution, but such conditions are often stress inducing and disruptive. Artificial growth systems can be used to induce and select genomic variation by changing external environmental conditions, thus, accelerating evolution. By using cloud computing and big-data analysis, we analyzed environmental stress factors for Pleurotus ostreatus by assessing, evaluating, and predicting information of the growth environment. Through the indexing of environmental stress, the growth environment can be precisely controlled and developed into a technology for improving crop quality and production. PMID:25874206

  8. Expert meeting on Child Growth and Micronutrient Deficiencies--New Initiatives for Developing Countries to Achieve Millennium Development Goals: executive summary report.

    PubMed

    Usfar, Avita A; Achadi, Endang L; Martorell, Reynaldo; Hadi, Hamam; Thaha, Razak; Jus'at, Idrus; Atmarita; Martianto, Drajat; Ridwan, Hardinsyah; Soekirman

    2009-01-01

    Undernutrition in early childhood has long-term physical and intellectual consequences. Improving child growth should start before the age of two years and be an integrated effort between all sectors, covering all aspects such as diet and nutrient intake, disease reduction, optimum child care, and improved environmental sanitation. To discuss these issues, the Indonesian Danone Institute Foundation organized an expert meeting on Child Growth and Micronutrient Deficiencies: New Initiatives for Developing Countries to Achieve Millennium Development Goals. The objective of the meeting was to have a retrospective view on child growth: lessons learned from programs to overcome under-nutrition in the developed countries and to relate the situation to the Indonesian context, as well as to discuss implications for future programs. Recommendations derived from the meeting include focus intervention on the window of opportunity group, re-activation of the Integrated Health Post at the village level, improvement of infant and young child feeding, expand food fortification intervention programs, strengthen supplementation programs with multi-micronutrient, and strengthening public and private partnership on food related programs. PMID:19786396

  9. A Computational Approach to Model Vascular Adaptation During Chronic Hemodialysis: Shape Optimization as a Substitute for Growth Modeling

    NASA Astrophysics Data System (ADS)

    Mahmoudzadeh Akherat, S. M. Javid; Boghosian, Michael; Cassel, Kevin; Hammes, Mary

    2015-11-01

    End-stage-renal disease patients depend on successful long-term hemodialysis via vascular access, commonly facilitated via a Brachiocephalic Fistula (BCF). The primary cause of BCF failure is Cephalic Arch Stenosis (CAS). It is believed that low Wall Shear Stress (WSS) regions, which occur because of the high flow rates through the natural bend in the cephalic vein, create hemodynamic circumstances that trigger the onset and development of Intimal Hyperplasia (IH) and subsequent CAS. IH is hypothesized to be a natural effort to reshape the vessel, aiming to bring the WSS values back to a physiologically acceptable range. We seek to explore the correlation between regions of low WSS and subsequent IH and CAS in patient-specific geometries. By utilizing a shape optimization framework, a method is proposed to predict cardiovascular adaptation that could potentially be an alternative to vascular growth and remodeling. Based on an objective functional that seeks to alter the vessel shape in such a way as to readjust the WSS to be within the normal physiological range, CFD and shape optimization are then coupled to investigate whether the optimal shape evolution is correlated with actual patient-specific geometries thereafter. Supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (R01 DK90769).

  10. Growth optimization of columnar nanostructured diamond films with high electrical performances for SOD applications

    NASA Astrophysics Data System (ADS)

    Lions, M.; Saada, S.; Pinault, M.-A.; Andrieu, F.; Faynot, O.; Bergonzo, P.

    2010-11-01

    In today's nanoelectronics devices, thermal management is a major issue to miniaturization. Because of its high thermal conductivity, diamond is an extremely interesting material for heat spreading. SOI (Silicon-On-Insulator) technology suffers of the poor thermal dissipation due to the silicon oxide buried layer. Thus, SOD (Silicon-On-Diamond) based on dielectrical diamond layer is seen as a promising candidate for future bulk solution. Polycrystalline diamond layers of extreme insulating properties (>1014Ωṡcm) are successfully synthesis with thickness under 150 nm on 2 inches silicon wafer. However, defects due to the growth and the polycrystal structure are responsible for the detrimental current stimulate by alternative electrical field. The defects activation energies were measured on columnar nanostructured diamond grown under different conditions. Values of 0.56 to 1.56 eV were found for defects in these films and were correlated to the growth parameters as well as the diamond morphology.

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

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

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

  13. Growth optimization and optical properties of AlGaNAs alloys

    SciTech Connect

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

    2014-04-28

    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.

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

    SciTech Connect

    Groves, James R; Matias, Vladimir; Stan, Liliana; De Paula, Raymond F; Hammond, Robert H; Clemens, Bruce M

    2010-01-01

    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.

  15. Characterization and optimization of 2-step MOVPE growth for single-mode DFB or DBR laser diodes

    NASA Astrophysics Data System (ADS)

    Bugge, F.; Mogilatenko, A.; Zeimer, U.; Brox, O.; Neumann, W.; Erbert, G.; Weyers, M.

    2011-01-01

    We have studied the MOVPE regrowth of AlGaAs over a grating for GaAs-based laser diodes with an internal wavelength stabilisation. Growth temperature and aluminium concentration in the regrown layers considerably affect the oxygen incorporation. Structural characterisation by transmission electron microscopy of the grating after regrowth shows the formation of quaternary InGaAsP regions due to the diffusion of indium atoms from the top InGaP layer and As-P exchange processes during the heating-up procedure. Additionally, the growth over such gratings with different facets leads to self-organisation of the aluminium content in the regrown AlGaAs layer, resulting in an additional AlGaAs grating, which has to be taken into account for the estimation of the coupling coefficient. With optimized growth conditions complete distributed feedback laser structures have been grown for different emission wavelengths. At 1062 nm a very high single-frequency output power of nearly 400 mW with a slope efficiency of 0.95 W/A for a 4 μm ridge-waveguide was obtained.

  16. Self-Optimizing Photoelectrochemical Growth of Nanopatterned Se-Te Films in Response to the Spectral Distribution of Incident Illumination.

    PubMed

    Carim, Azhar I; Batara, Nicolas A; Premkumar, Anjali; Atwater, Harry A; Lewis, Nathan S

    2015-10-14

    Photoelectrochemical growth of Se-Te films spontaneously produces highly ordered, nanoscale lamellar morphologies with periodicities that can be tuned by varying the illumination wavelength during deposition. This phenomenon has been characterized further herein by determining the morphologies of photoelectrodeposited Se-Te films in response to tailored spectral illumination profiles. Se-Te films grown under illumination from four different sources, having similar average wavelengths but having spectral bandwidths that spanned several orders of magnitude, all nevertheless produced similar structures which had a single, common periodicity as quantitatively identified via Fourier analysis. Film deposition using simultaneous illumination from two narrowband sources, which differed in average wavelength by several hundred nanometers, resulted in a structure with only a single periodicity intermediate between the periods observed when either source alone was used. This single periodicity could be varied by manipulating the relative intensity of the two sources. An iterative model that combined full-wave electromagnetic effects with Monte Carlo growth simulations, and that considered only the fundamental light-material interactions during deposition, was in accord with the morphologies observed experimentally. Simulations of light absorption and concentration in idealized lamellar arrays, in conjunction with all of the available data, additionally indicated that a self-optimization of the periodicity of the nanoscale pattern, resulting in the maximization of the anisotropy of interfacial light absorption in the three-dimensional structure, is consistent with the observed growth process of such films. PMID:26390263

  17. Suppressing Nitrite-oxidizing Bacteria Growth to Achieve Nitrogen Removal from Domestic Wastewater via Anammox Using Intermittent Aeration with Low Dissolved Oxygen

    PubMed Central

    Ma, Bin; Bao, Peng; Wei, Yan; Zhu, Guibing; Yuan, Zhiguo; Peng, Yongzhen

    2015-01-01

    Achieving nitrogen removal from domestic wastewater using anaerobic ammonium oxidation (anammox) has the potential to make wastewater treatment energy-neutral or even energy-positive. The challenge is to suppress the growth of nitrite-oxidizing bacteria (NOB). This study presents a promising method based on intermittent aeration with low dissolved oxygen to limit NOB growth, thereby providing an advantage to anammox bacteria to form a partnership with the ammonium-oxidizing bacteria (AOB). The results showed that NOB was successfully suppressed using that method, with the relative abundance of NOB maintained between 2.0–2.6%, based on Fluorescent in-situ Hybridization. Nitrogen could be effectively removed from domestic wastewater with anammox at a temperature above 20 °C, with an effluent total nitrogen (TN) concentration of 6.6 ± 2.7 mg/L, while the influent TN and soluble chemical oxygen demand were 62.6 ± 3.1 mg/L and 88.0 ± 8.1 mg/L, respectively. PMID:26354321

  18. Kinetics of phase growth in Nb3Sn formation for heat treatment optimization

    SciTech Connect

    Emanuela Barzi; Sara Mattafirri

    2002-10-25

    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.

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

    PubMed Central

    Young, Bridget E.; Krebs, Nancy F.

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Taylor, Dane; Restrepo, Juan G.

    2011-06-01

    The principal eigenvalue ? of a networks 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.

  1. 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)

    Bonchiş, N.; Balint, Şt.

    2010-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

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

    PubMed

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

    2013-07-10

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

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

    NASA Astrophysics Data System (ADS)

    Gao, B.; Kakimoto, K.

    2014-04-01

    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.

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

    PubMed Central

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

    2014-01-01

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

  6. Growth Optimization of III-N Electronic Devices by Plasma-Assisted Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Ahmadi, Elaheh

    InAlN has received significant attention due to its great potential for electronic and optoelectronic applications. In particular, In 0.18Al0.82N presents the advantage of being lattice-matched to GaN and simultaneously exhibiting a high spontaneous polarization charge, making In0.18 Al0.82N attractive for use as the barrier layer in high-electron-mobility transistors (HEMTs). However, in the case of InAlN growth by plasma-assisted molecular beam epitaxy (PAMBE), a strong non-uniformity in the in-plane In distribution was observed for both N-face and metal-face In0.18Al 0.82N. This compositional inhomogeneity manifests itself as a columnar microstructure with AlN-rich cores (5-10 nm in width) and InN-rich intercolumn boundaries. Because of the large differences between the bandgaps and polarization of InN and AlN, this non-uniformity in InAlN composition could be a source of scattering, leading to mobility degradation in HEMTs. In this work, the growth conditions for high quality lattice-matched InAlN layers on free-standing GaN substrates were explored by plasma-assisted molecular beam epitaxy (PAMBE) in the N-rich regime. The microstructure of N-face InAlN layers, lattice-matched to GaN, was investigated by scanning transmission electron microscopy and atom probe tomography. Microstructural analysis showed an absence of the lateral composition modulation that was previously observed in InAlN films grown by PAMBE. Using same growth conditions for InAlN layer, N-face GaN/AlN/GaN/InAlN high-electron-mobility transistors with lattice-matched InAlN back barriers were grown directly on SiC. A room temperature two-dimensional electron gas (2DEG) mobility of 1100cm2 V-1s-1 and 2DEG sheet charge density of 1.9 x1013 cm 2 was measured on these devices. However, the threading dislocation density (TDD) of GaN grown directly on SiC by PAMBE (≈2 x10 10 cm-2 ) is two orders of magnitude higher than GaN grown by MOCVD on SiC or sapphire (≈5 x10 8 cm-2). This high TDD can severely degrade the 2DEG mobility, especially at lower 2DEG sheet densities. Relatively low TDD (≈5 x 108 cm-2 ) on MOCVD-grown GaN substrates motivated us to study the growth of N-face GaN-based HEMT structures with InAlN backbarriers on such substrates. Since on-axis GaN-on-sapphire substrates with low threading dislocation density are not available in the N-face orientation, we explored the growth of InAlN on vicinal (4° miscut along GaN 101¯0 ) GaN-on-sapphire substrates. The microstructure of In 0.18Al0.82N layers grown by PAMBE at different temperatures was studied using scanning transmission electron microscopy (STEM). The cross-sectional and plan-view STEM images revealed lateral variations in the InAlN composition along 101¯0 (perpendicular to the step edges), in addition to step bunching in InAlN layers thicker than 10 nm. N-face HEMTs with lattice-matched InAlN backbarriers were then grown on these vicinal substrates with different InAlN thicknesses. Transmission line measurements showed that step bunching and lateral variation of InAlN composition degraded the 2DEG mobility in the directions parallel and perpendicular to the steps. Two good measures of the device quality concerning the power loss in power switch and high frequency switch applications are Huang material figure of merit, and Baliga high-frequency figure of merit, respectively, which shows that for any fixed material system, power loss reduces by increasing the mobility of the 2DEG. Therefore, it is very important to understand the source of scattering mechanisms which affect the 2DEG mobility. In this work, we studied effect of decreasing channel thickness or increasing gate reverse bias on charge density and 2DEG mobility in N-face HEMT structure. Our calculations showed that increasing the gate reverse bias and decreasing the channel thickness both reduce the 2DEG mobility. This trend has been observed by experiment as well. Previously, it was believed that increasing the gate reverse bias or decreasing the channel thickness in N-face GaN-based HEMT structures lead to deeper penetration of the 2DEG wavefunction into the barrier, and consequently, higher interface roughness and alloy scattering rates. Although this statement is true, our calculations revealed that the penetration of the 2DEG into the barrier and, therefore, 2DEG mobility limited by alloy and interface roughness scattering mechanisms do not vary significantly by increasing gate reverse bias or decreasing the channel thickness. therefore, these two scattering mechanisms are not enough to explain the significant drop in the 2DEG mobility observed in experiments. We believe that the charged trap states at the AlGaN-GaN interface, where the 2DEG forms, are responsible for this 2DEG mobility reduction. (Abstract shortened by UMI.).

  7. Ferroelectric characterization and growth optimization of thermally evaporated vinylidene fluoride thin films

    NASA Astrophysics Data System (ADS)

    Foreman, K.; Hong, N.; Labedz, C.; Shearer, M.; Ducharme, Stephen; Adenwalla, S.

    2016-01-01

    Organic thin films have numerous advantages over inorganics in device processing and price. The large polarization of the organic ferroelectric oligomer vinylidene fluoride (VDF) could prove useful for both device applications and the investigation of fundamental physical phenomena. A VDF oligomer thin film vacuum deposition process, such as thermal evaporation, preserves film and interface cleanliness, but is challenging, with successful deposition occurring only within a narrow parameter space. We report on the optimal deposition parameters for VDF oligomer thin films, refining the parameter space for successful deposition, resulting in a high yield of robust ferroelectric films. In particular, we investigate the influence of deposition parameters on surface roughness, and the role that roughness plays in sample yield. The reliable production of ferroelectric films allowed us to perform detailed measurements of previously unreported properties, including the Curie temperature, the temperature and thickness dependence of the coercive field, the melting temperature, and the index of refraction. The ability to successfully grow robust, switchable, well-characterized films makes VDF oligomer a viable candidate in the field of organic ferroelectrics.

  8. Influence and optimization of growth substrates on indigo formation by a novel isolate Acinetobacter sp. PP-2.

    PubMed

    Qu, Yuanyuan; Pi, Wenqing; Ma, Fang; Zhou, Jiti; Zhang, Xuwang

    2010-06-01

    In this study, a novel indigo-producing bacterial strain PP-2 was isolated from activated sludge. It was identified as Acinetobacter sp. according to phylogenetic similarity of 16S rRNA gene sequence. This isolate was able to produce indigo from indole by utilizing a wide range of aromatic hydrocarbons. The results of SDS-PAGE analysis showed that the enzyme system induced by phenol was more abundant than that induced by other aromatic hydrocarbons. And the effects of metal ions on indigo production were also investigated, which indicated that the activity of cells induced with phenol could be inhibited by 0.5mM Fe(3+). Response surface methodology (RSM) was applied to optimize the process of indigo bio-production. The results exhibited that the maximal yield was achieved with 157.92 mg L(-1) phenol and 205.32 mg L(-1) indole. Under the optimal conditions, the indigo yield and transformation efficiency of indole were 202.92 mg L(-1) and 88%, respectively. PMID:20156680

  9. Optimization of treatment parameters for the use of FLYASH amended composts for plant growth

    SciTech Connect

    Bacon, B.B.; Menon, M.P.; Ghuman, G.S.; James, J.; Adriano, D.C.; Chandra, K. )

    1990-01-01

    In continuation of the authors efforts to utilize coal fly ash as an amendment to organic manure for vegetation, four parameters such as the nature of the manure, plant-type, ash to manure and soil to amended compost ratios were investigated. a high grade organic manure, Gotta Grow, and a low grade manure, compost-manure, compost-toast, (Bricko Farm products) along with a home-made composed were used to make fly ash-amended composts. Four plants, collard green, mustard green, corn and sorghum were selected for study under greenhouse conditions. Keeping other variables constant, the fly ash to manure ratio was changed from 0 to 60% FA, and compost to soil ratio from 0 to 25%. The plants were grown for approximately 8 weeks and harvested. The plant yield was measured both before and after drying. It was found that out of four plants, yield from corn is the highest when fly ash-amended compost-toast (20% FA) was used at a compost to soil ratio of 1:3. The plant samples are being analyzed for major and minor elements including boron which is detrimental to the growth of plants.

  10. Optimization of conditions for growth of vanadium dioxide thin films on silicon by pulsed-laser deposition

    NASA Astrophysics Data System (ADS)

    Shibuya, Keisuke; Sawa, Akihito

    2015-10-01

    We systematically examined the effects of the substrate temperature (TS) and the oxygen pressure (PO2) on the structural and optical properties polycrystalline V O2 films grown directly on Si(100) substrates by pulsed-laser deposition. A rutile-type V O2 phase was formed at a TS ≥ 450 °C at PO2 values ranging from 5 to 20 mTorr, whereas other structures of vanadium oxides were stabilized at lower temperatures or higher oxygen pressures. The surface roughness of the V O2 films significantly increased at growth temperatures of 550 °C or more due to agglomeration of V O2 on the surface of the silicon substrate. An apparent change in the refractive index across the metal-insulator transition (MIT) temperature was observed in V O2 films grown at a TS of 450 °C or more. The difference in the refractive index at a wavelength of 1550 nm above and below the MIT temperature was influenced by both the TS and PO2, and was maximal for a V O2 film grown at 450 °C under 20 mTorr. Based on the results, we derived the PO2 versus 1/TS phase diagram for the films of vanadium oxides, which will provide a guide to optimizing the conditions for growth of V O2 films on silicon platforms.

  11. Effects of fiber inclusion on growth performance and nutrient digestibility of piglets reared under optimal or poor hygienic conditions.

    PubMed

    Berrocoso, J D; Menoyo, D; Guzmán, P; Saldaña, B; Cámara, L; Mateos, G G

    2015-08-01

    Two experiments were conducted to study the effects of inclusion of additional fiber in the Phase I diet on growth performance and nutrient digestibility in piglets reared under "optimal" or "poor" hygienic conditions. In both experiments, the design was completely randomized with a control diet that contained 2.2% crude fiber and 8 additional isonutritive diets that included 2.5 or 5.0% of sugar beet pulp (SBP), straw, oat hulls (OH), or wheat middlings (WHM). Preplanned polynomial contrasts were used to study the effects of 1) fiber inclusion (control diet vs. average of the 8 fiber-containing diets), 2) source of fiber, 3) level of fiber, and 4) interaction between source and level of fiber. In Exp. 1 (clean barn), fiber inclusion increased ( < 0.01) the incidence of postweaning diarrhea (PWD) and reduced ( < 0.05) feed efficiency and apparent total tract digestibility (ATTD) of all nutrients except that of CP, which was not affected. Piglet performance was not affected by source or level of dietary fiber. The ATTD of all nutrients decreased ( < 0.05) as the level of fiber increased and was lower in pigs fed straw or OH than in pigs fed SBP or WHM. The apparent ileal digestibility of GE and DM decreased ( < 0.05) with fiber inclusion, a reduction that was more pronounced ( < 0.05) with straw or SBP than with OH inclusion, with WHM inclusion being intermediate. Fiber inclusion did not affect villous height to crypt depth ratio of the ileum mucosa. The inclusion of 5% of a fiber source increased and counts in the cecum ( < 0.001) but the to ratio was not affected. In Exp. 2 (dirty barn), fiber inclusion did not affect piglet performance but tended to increase PWD ( = 0.07). Also, fiber inclusion reduced ( < 0.05) the ATTD of all dietary components except that of CP, which was not affected. Source and level of fiber did not affect ATTD of nutrients except for DM, which was greater for pigs fed SBP than for pigs fed straw ( < 0.05). In conclusion, in the current research, pigs reared under optimal hygienic conditions had lower incidence of PWD, better growth performance, and greater DM and GE digestibility than pigs reared under poor hygienic conditions. An excess of dietary fiber was more detrimental for all these traits in piglets reared under optimal hygienic conditions. The effects of the source and level of fiber on piglet performance was limited in the 2 experiments. PMID:26440172

  12. Four Novel Genes Required for Optimal Photoautotrophic Growth of the Cyanobacterium Synechocystis sp. Strain PCC 6803 Identified by In Vitro Transposon Mutagenesis

    PubMed Central

    Zhang, Shulu; Laborde, Susan M.; Frankel, Laurie K.; Bricker, Terry M.

    2004-01-01

    Four novel Synechocystis sp. strain PCC 6803 genes (sll1495, sll0804, slr1306, and slr1125) which encode hypothetical proteins were determined by transposon mutagenesis to be required for optimal photoautotrophic growth. Mutations were also recovered in ccmK4, a carboxysome coat protein homologue, and me, the decarboxylating NADP+-dependent malic enzyme. This is the first report that these known genes are required for optimal photoautotrophy. PMID:14729717

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed Central

    Merchant, Sabeeha S.; Helmann, John D.

    2014-01-01

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

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

    ERIC Educational Resources Information Center

    Shin, Tacksoo

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Shin, Tacksoo

    2012-01-01

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

  17. Purification optimization for a recombinant single-chain variable fragment against type 1 insulin-like growth factor receptor (IGF-1R) by using design of experiment (DoE).

    PubMed

    Song, Yong-Hong; Sun, Xue-Wen; Jiang, Bo; Liu, Ji-En; Su, Xian-Hui

    2015-12-01

    Design of experiment (DoE) is a statistics-based technique for experimental design that could overcome the shortcomings of traditional one-factor-at-a-time (OFAT) approach for protein purification optimization. In this study, a DoE approach was applied for optimizing purification of a recombinant single-chain variable fragment (scFv) against type 1 insulin-like growth factor receptor (IGF-1R) expressed in Escherichia coli. In first capture step using Capto L, a 2-level fractional factorial analysis and successively a central composite circumscribed (CCC) design were used to identify the optimal elution conditions. Two main effects, pH and trehalose, were identified, and high recovery (above 95%) and low aggregates ratio (below 10%) were achieved at the pH range from 2.9 to 3.0 with 32-35% (w/v) trehalose added. In the second step using cation exchange chromatography, an initial screening of media and elution pH and a following CCC design were performed, whereby the optimal selectivity of the scFv was obtained on Capto S at pH near 6.0, and the optimal conditions for fulfilling high DBC and purity were identified as pH range of 5.9-6.1 and loading conductivity range of 5-12.5 mS/cm. Upon a further gel filtration, the final purified scFv with a purity of 98% was obtained. Finally, the optimized conditions were verified by a 20-fold scale-up experiment. The purities and yields of intermediate and final products all fell within the regions predicted by DoE approach, suggesting the robustness of the optimized conditions. We proposed that the DoE approach described here is also applicable in production of other recombinant antibody constructs. PMID:26297993

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

    PubMed Central

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

    2014-01-01

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

  19. The Role of Air-Sea Interaction and Non-Normality in Controlling the Structure and Growth of Optimal Perturbations of ENSO

    NASA Astrophysics Data System (ADS)

    Moore, A. M.; Vialard, J.; Weaver, A.; Anderson, D. L.; Kleeman, R.; Johnson, J. R.

    2001-12-01

    The optimal perturbations of low-frequency coupled ocean-atmosphere eigenmodes are explored using a hierarchy of hybrid coupled models. The model hierarchy consists of an OGCM of the tropical Pacific ocean coupled to three different atmospheric models: a statistical model, a simple dynamical model, and a model of the atmospheric boundary layer. The structure and growth rate of the optimal perturbations is found to depend strongly on the atmospheric dynamics and air-sea interaction processes that are included in each model. It is shown that these processes influence the degree of linear dependence of the system eigenmodes which in turn directly controls the growth attainable by the optimal perturbations. The implications of these findings for ENSO predictability and ensemble prediction will be discussed.

  20. Temperature Shift Experiments Suggest That Metabolic Impairment and Enhanced Rates of Photorespiration Decrease Organic Acid Levels in Soybean Leaflets Exposed to Supra-Optimal Growth Temperatures

    PubMed Central

    Sicher, Richard C.

    2015-01-01

    Elevated growth temperatures are known to affect foliar organic acid concentrations in various plant species. In the current study, citrate, malate, malonate, fumarate and succinate decreased 40 to 80% in soybean leaflets when plants were grown continuously in controlled environment chambers at 36/28 compared to 28/20 °C. Temperature effects on the above mentioned organic acids were partially reversed three days after plants were transferred among optimal and supra-optimal growth temperatures. In addition, CO2 enrichment increased foliar malate, malonate and fumarate concentrations in the supra-optimal temperature treatment, thereby mitigating effects of high temperature on respiratory metabolism. Glycerate, which functions in the photorespiratory pathway, decreased in response to CO2 enrichment at both growth temperatures. The above findings suggested that diminished levels of organic acids in soybean leaflets upon exposure to high growth temperatures were attributable to metabolic impairment and to changes of photorespiratory flux. Leaf development rates differed among temperature and CO2 treatments, which affected foliar organic acid levels. Additionally, we report that large decreases of foliar organic acids in response to elevated growth temperatures were observed in legume species. PMID:26251925

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

    PubMed Central

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

    2014-01-01

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

  2. High-performance n-type organic semiconductors: incorporating specific electron-withdrawing motifs to achieve tight molecular stacking and optimized energy levels.

    PubMed

    Yun, Sun Woo; Kim, Jong H; Shin, Seunghoon; Yang, Hoichang; An, Byeong-Kwan; Yang, Lin; Park, Soo Young

    2012-02-14

    Novel π–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 cm2 V−1s−1 and on-off current ratios PMID:22403831

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

    SciTech Connect

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

    2012-01-16

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

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

    PubMed

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

    2012-12-31

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  7. Optimal Amount of Basic Fibroblast Growth Factor in Gelatin Sponges Incorporating β-Tricalcium Phosphate with Chondrocytes

    PubMed Central

    Otani, Yushi; Komura, Hiroko; Ishimaru, Tetsuya; Konishi, Kenichiro; Komuro, Hiroaki; Hoshi, Kazuto; Takato, Tsuyoshi; Tabata, Yasuhiko; Iwanaka, Tadashi

    2015-01-01

    Background: A gelatin sponge with slowly releasing basic fibroblast growth factor (b-FGF) enhances chondrogenesis. This study investigated the optimal amount of b-FGF in gelatin sponges to fabricate engineered cartilage. Materials and Methods: b-FGF (0, 10, 100, 500, 1000, and 2000 μg/cm3)-impregnated gelatin sponges incorporating β-tricalcium phosphate (β-TCP) were produced. Chondrocytes were isolated from the auricular cartilage of C57B6J mice and expanded. The expanded auricular chondrocytes (10×106 cells/cm3) were seeded onto the gelatin sponges, which served as scaffolds. The construct assembly was implanted in the subcutaneous space of mice through a syngeneic fashion. Thereafter, constructs were retrieved at 2, 4, or 6 weeks. Results: (1) Morphology: The size of implanted constructs was larger than the size of the scaffold with 500, 1000, and 2000 μg/cm3 b-FGF-impregnated gelatin sponges incorporating β-TCP at 4 and 6 weeks after implantation. (2) The weight of the constructs increased roughly proportional to the increase in volume of the b-FGF-impregnated scaffold at 2, 4, and 6 weeks after implantation, except in the 2000 μg/cm3 b-FGF-impregnated constructs group. (3) Histological examination: Extracellular matrix in the center of the constructs was observed in gelatin sponges impregnated with more than 100 μg/cm3 b-FGF at 4 weeks after implantation. The areas of cells with an abundant extracellular matrix were positive for cartilage-specific marker type 2 collagen in the constructs. (4) Protein assay: Glycosaminoglycan and collagen type 2 expression were significantly increased at 4 and 6 weeks on implantation of gelatin sponges impregnated with more than 100 μg/cm3 b-FGF. At 6 weeks after implantation, the ratio of type 2 collagen to type 1 collagen in constructs impregnated with 100 μg/cm3 or more b-FGF was higher than that in mice auricular cartilage. Conclusion: Gelatin sponges impregnated with more than 100 μg/cm3 b-FGF incorporating β-TCP with chondrocytes (10×106 cells/cm3) can fabricate engineered cartilage at 4 weeks after implantation. PMID:25287675

  8. 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

    Knupp, P.M.

    1999-03-26

    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.

  9. Optimal Flow.

    ERIC Educational Resources Information Center

    Norman, Donald A.

    1996-01-01

    Discusses the educational applications of experimental psychologist Mihaly Csikszentmihalyi's theory of peak experience, or optimal flow. Optimal flow refers to the receptive state people achieve when they are engaged in interesting and challenging activity. Includes an insightful critique of multimedia instruction from this perspective. (MJP)

  10. 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

    Brooks, Morris, Jr.

    2009-01-01

    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

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  12. The Economic Benefits of Closing Educational Achievement Gaps: Promoting Growth and Strengthening the Nation by Improving the Educational Outcomes of Children of Color

    ERIC Educational Resources Information Center

    Lynch, Robert G.; Oakford, Patrick

    2014-01-01

    Our nation is currently experiencing growing levels of income and wealth inequality, which are contributing to longstanding racial and ethnic gaps in education outcomes and other areas. This report quantifies the economic benefits of closing one of the most harmful racial and ethnic gaps: the educational achievement gap that exists between black…

  13. 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

    Brooks, Morris, Jr.

    2009-01-01

    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…

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  15. [Soil dryness characteristics of alfalfa cropland and optimal growth years of alfalfa on the Loess Plateau of central Gansu, China].

    PubMed

    Luo, Zhu-zhu; Li, Ling-ling; Niu, Yi-ning; Cai, Li-qun; Zhang, Ren-zhi; Xie, Jun-hong

    2015-10-01

    This paper investigated soil moisture in alfalfa (Medicago sativa) cropland with different growth years (1, 3, 8, 12 and 14 years) and discussed the optimum growth years of alfalfa on the Loess Plateau of central Gansu. The results showed that the soil moisture along 0-300 cm soil profile of alfalfa croplands with different growth years was obviously lower than that of the local soil stable moisture. The soil water contents in croplands with alfalfa that had grown for 12 and 14 years were only 9.2% and 7.1% of local soil stable moisture, respectively, which were even lower than the lower limit of alfalfa growth. The average soil dryness indexes along 0-300 cm soil profile in 1, 3, 8, 12 and 14 years alfalfa croplands were 125.4%, 30.5%, 18.4%, -34.2% and -83.3% respectively. The results indicated that soil dryness occurred to varying degrees with different growth years except croplands with alfalfa grown for 1 year. With the increase of growth years of alfalfa, the soil dryness intensity increased and the soil dryness rate decreased. According to the soil moisture and alfalfa productivity results in this study, it could be concluded that the optimum growth years of alfalfa are 8-10 years in semiarid areas of the Loess Plateau. PMID:26995914

  16. Optimization of growth conditions for (La1-yPry)1-x CaxMnO3 thin films on annealed oxide substrates

    NASA Astrophysics Data System (ADS)

    Schaefer, Brian; Grant, Daniel; Biswas, Amlan

    2014-03-01

    Consistent growth of flat, epitaxial thin films is essential for uncovering the unique transport characteristics of rare-earth manganite systems. We have developed pulsed laser deposition growth conditions for (La1-yPry)1-x CaxMnO3 (LPCMO, y = 0.4, 0.5, 0.6) thin films on annealed NdGaO3 (NGO) and SrTiO3 (STO) substrates. The extra annealing step for NGO and STO produces atomically flat substrates with well-defined terraces of unit cell step height. Films grown on these annealed substrates demonstrate better lattice matching compared to films grown on as-received substrates. Consequently, annealing substrates before film growth leads to higher quality thin films with a more controllable thickness. We demonstrate that these optimized growth parameters yield LPCMO thin films that are also atomically flat, as confirmed by atomic force microscopy. We are using these thin films to restrict phase growth to reduced dimensions and to study the origin of thermodynamic phase competition due to first order transitions in manganites. NSF DMR-0804452

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

    SciTech Connect

    Fedoryshyn, Yuriy; Ostinelli, Olivier; Alt, Andreas; Pallin, Angel; Bolognesi, Colombo R.

    2014-01-28

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

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

    NASA Astrophysics Data System (ADS)

    Srinivasan, V.; Kumar, P.

    2012-12-01

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

  19. Application of response surface methodology in optimization of lactic acid fermentation of radish: effect of addition of salt, additives and growth stimulators.

    PubMed

    Joshi, V K; Chauhan, Arjun; Devi, Sarita; Kumar, Vikas

    2015-08-01

    Lactic acid fermentation of radish was conducted using various additive and growth stimulators such as salt (2 %-3 %), lactose, MgSO4 + MnSO4 and Mustard (1 %, 1.5 % and 2 %) to optimize the process. Response surface methodology (Design expert, Trial version 8.0.5.2) was applied to the experimental data for the optimization of process variables in lactic acid fermentation of radish. Out of various treatments studied, only the treatments having ground mustard had an appreciable effect on lactic acid fermentation. Both linear and quadratic terms of the variables studied had a significant effect on the responses studied. The interactions between the variables were found to contribute to the response at a significant level. The best results were obtained in the treatment with 2.5 % salt, 1.5 % lactose, 1.5 % (MgSO4 + MnSO4) and 1.5 % mustard. These optimized concentrations increased titrable acidity and LAB count, but lowered pH. The second-order polynomial regression model determined that the highest titrable acidity (1.69), lowest pH (2.49) and maximum LAB count (10 × 10(8) cfu/ml) would be obtained at these concentrations of additives. Among 30 runs conducted, run 2 has got the optimum concentration of salt- 2.5 %, lactose- 1.5 %, MgSO4 + MnSO4- 1.5 % and mustard- 1.5 % for lactic acid fermentation of radish. The values for different additives and growth stimulators optimized in this study could successfully be employed for the lactic acid fermentation of radish as a postharvest reduction tool and for product development. PMID:26243913

  20. Algorithmic co-optimization of genetic constructs and growth conditions: application to 6-ACA, a potential nylon-6 precursor.

    PubMed

    Zhou, Hui; Vonk, Brenda; Roubos, Johannes A; Bovenberg, Roel A L; Voigt, Christopher A

    2015-12-01

    Optimizing bio-production involves strain and process improvements performed as discrete steps. However, environment impacts genotype and a strain that is optimal under one set of conditions may not be under different conditions. We present a methodology to simultaneously vary genetic and process factors, so that both can be guided by design of experiments (DOE). Advances in DNA assembly and gene insulation facilitate this approach by accelerating multi-gene pathway construction and the statistical interpretation of screening data. This is applied to a 6-aminocaproic acid (6-ACA) pathway in Escherichia coli consisting of six heterologous enzymes. A 32-member fraction factorial library is designed that simultaneously perturbs expression and media composition. This is compared to a 64-member full factorial library just varying expression (0.64 Mb of DNA assembly). Statistical analysis of the screening data from these libraries leads to different predictions as to whether the expression of enzymes needs to increase or decrease. Therefore, if genotype and media were varied separately this would lead to a suboptimal combination. This is applied to the design of a strain and media composition that increases 6-ACA from 9 to 48 mg/l in a single optimization step. This work introduces a generalizable platform to co-optimize genetic and non-genetic factors. PMID:26519464

  1. Algorithmic co-optimization of genetic constructs and growth conditions: application to 6-ACA, a potential nylon-6 precursor

    PubMed Central

    Zhou, Hui; Vonk, Brenda; Roubos, Johannes A.; Bovenberg, Roel A.L.; Voigt, Christopher A.

    2015-01-01

    Optimizing bio-production involves strain and process improvements performed as discrete steps. However, environment impacts genotype and a strain that is optimal under one set of conditions may not be under different conditions. We present a methodology to simultaneously vary genetic and process factors, so that both can be guided by design of experiments (DOE). Advances in DNA assembly and gene insulation facilitate this approach by accelerating multi-gene pathway construction and the statistical interpretation of screening data. This is applied to a 6-aminocaproic acid (6-ACA) pathway in Escherichia coli consisting of six heterologous enzymes. A 32-member fraction factorial library is designed that simultaneously perturbs expression and media composition. This is compared to a 64-member full factorial library just varying expression (0.64 Mb of DNA assembly). Statistical analysis of the screening data from these libraries leads to different predictions as to whether the expression of enzymes needs to increase or decrease. Therefore, if genotype and media were varied separately this would lead to a suboptimal combination. This is applied to the design of a strain and media composition that increases 6-ACA from 9 to 48 mg/l in a single optimization step. This work introduces a generalizable platform to co-optimize genetic and non-genetic factors. PMID:26519464

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

    SciTech Connect

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

    2000-04-01

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

  3. Optimization of growth medium for Sporosarcina pasteurii in bio-based cement pastes to mitigate delay in hydration kinetics.

    PubMed

    Williams, Sarah L; Kirisits, Mary Jo; Ferron, Raissa Douglas

    2016-04-01

    Microbial-induced calcium carbonate precipitation has been identified as a novel method to improve durability and remediate cracks in concrete. One way to introduce microorganisms to concrete is by replacing the mixing water with a bacterial culture in nutrient medium. In the literature, yeast extract often has been used as a carbon source for this application; however, severe retardation of hydration kinetics has been observed when yeast extract is added to cement. This study investigates the suitability of alternative carbon sources to replace yeast extract for microbial-induced calcium carbonate precipitation in cement-based materials. A combination of meat extract and sodium acetate was identified as a suitable replacement in growth medium for Sporosarcina pasteurii; this alternative growth medium reduced retardation by 75 % (as compared to yeast extract) without compromising bacterial growth, urea hydrolysis, cell zeta potential, and ability to promote calcium carbonate formation. PMID:26795346

  4. Optimization of growth medium and enzyme assay conditions for crude cellulases produced by a novel thermophilic and cellulolytic bacterium, Anoxybacillus sp. 527.

    PubMed

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

    2010-03-01

    A newly isolated Anoxybacillus sp. 527 was found to grow on crystalline cellulose as sole carbon and energy sources. Cellulases secreted by strain 527 were better induced by cellobiose, followed by glucose, lactose, sucrose, and cellulose. Cellulase secretion was enhanced by an optimized medium. Cellulase activity was increased by the addition of Ca(2+) and NH (4) (+) and achieved maximum as 7.0 FPU ml(-1) at 70 degrees C and pH 6.0. Even at 100 degrees C, the enzymes were still active, which implies their potential application in large-scale cellulose conversion process. PMID:19504357

  5. Optimization of growth medium and enzyme assay conditions for crude cellulases produced by a novel thermophilic and cellulolytic bacterium, Anoxybacillus sp. 527.

    TOXLINE Toxicology Bibliographic Information

    Liang Y; Feng Z; Yesuf J; Blackburn JW

    2010-03-01

    A newly isolated Anoxybacillus sp. 527 was found to grow on crystalline cellulose as sole carbon and energy sources. Cellulases secreted by strain 527 were better induced by cellobiose, followed by glucose, lactose, sucrose, and cellulose. Cellulase secretion was enhanced by an optimized medium. Cellulase activity was increased by the addition of Ca(2+) and NH (4) (+) and achieved maximum as 7.0 FPU ml(-1) at 70 degrees C and pH 6.0. Even at 100 degrees C, the enzymes were still active, which implies their potential application in large-scale cellulose conversion process.

  6. Osmoregulated Periplasmic Glucans (OPGs) of Salmonella enterica serovars Typhimurium are needed for optimal growth under nutrient limiting- hypoosmotic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Osmoregulated periplasmic glucans (OPGs) are major periplasmic constituents of gram negative bacteria. Synthesis of OPGs is regulated by the osmolarity of the growth medium. The role of OPGs has been postulated in plant-symbiotic as well as pathogenic microorganisms. On the other hand, opg mutant...

  7. Achieving Optimal Enrollments and Tuition Revenues.

    ERIC Educational Resources Information Center

    Ihlanfeldt, William

    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…

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

    USGS Publications Warehouse

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

    2011-01-01

    The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection in RTG-2 cells of NV fused to green fluorescent protein (GFP), a nuclear localization of NV was demonstrated. Deletion analyses showed that the 32EGDL35 residues were essential for nuclear localization of NV protein, and fusion of these 4 amino acids to GFP directed its transport to the nucleus. We generated a recombinant IHNV, rIHNV-NV-ΔEGDL 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-ΔNV-GFP) were used as controls. RTG-2 cells infected with rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL 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-ΔNV-GFP and rIHNV-NV-ΔEGDL were inhibited by poly I:C. In addition, both rIHNV-ΔNV and rIHNV-NV-ΔEGDL 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.

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

    PubMed

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

    2001-01-01

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

  10. Growth optimization and characterization of GaN epilayers on multifaceted (111) surfaces etched on Si(100) substrates

    SciTech Connect

    Ansah-Antwi, KwaDwo Konadu Chua, Soo Jin; Soh, Chew Beng; Liu, Hongfei

    2015-11-15

    The four nearest Si(111) multifaceted sidewalls were exposed inside an array of 3 μm-wide square holes patterned on an Si(100) substrate, and this patterned Si(100) substrate was used as a substrate for the deposition of a gallium nitride (GaN) epilayer. Subsequently the effect that the growth pressure, the etched-hole profiles, and the etched-hole arrangement had upon the quality of the as-grown GaN was investigated. The coalescence of the as-grown GaN epilayer on the exposed Si(111) facets was observed to be enhanced with reduced growth pressure from 120 to 90 Torr. A larger Si(001) plane area at the bottom of the etched holes resulted in bidirectional GaN domains, which resulted in poor material quality. The bidirectional GaN domains were observed as two sets of six peaks via a high-resolution x-ray diffraction phi scan of the GaN(10-11) reflection. It was also shown that a triangular array of etched holes was more desirable than square arrays of etched holes for the growth high-quality and continuous GaN films.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

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

    PubMed Central

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

    2009-01-01

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

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

    PubMed Central

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

    2012-01-01

    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. PMID:22090129

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

    NASA Astrophysics Data System (ADS)

    Jagtap, Piyush; Kumar, Praveen

    2015-04-01

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

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

    PubMed Central

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

    2011-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  17. 64 μW pulsed terahertz emission from growth optimized InGaAs/InAlAs heterostructures with separated photoconductive and trapping regions

    SciTech Connect

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

    2013-08-05

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

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

    PubMed Central

    Rothstein, Steven J.

    2014-01-01

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

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

    PubMed

    Ranathunge, Kosala; El-Kereamy, Ashraf; Gidda, Satinder; Bi, Yong-Mei; Rothstein, Steven J

    2014-03-01

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

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

    PubMed Central

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

    2008-01-01

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

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

    PubMed Central

    Babi?, Janja; Likozar, Bla; Pavko, Aleksander

    2012-01-01

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

  2. Fibroblast Growth Factor (FGF) Receptor/FGF Inhibitors: Novel Targets and Strategies for Optimization of Response of Solid Tumors.

    PubMed

    Hierro, Cinta; Rodon, Jordi; Tabernero, Josep

    2015-12-01

    The fibroblast growth factor receptor (FGFR) pathway plays a major role in several biological processes, from organogenesis to metabolism homeostasis and angiogenesis. Several aberrations, including gene amplifications, point mutations, and chromosomal translocations have been described across solid tumors. Most of these molecular alterations promote multiple steps of carcinogenesis in FGFR oncogene-addicted cells, increasing cell proliferation, angiogenesis, and drug resistance. Data suggest that upregulation of FGFR signaling is a common event in many cancer types. The FGFR pathway thus arises as a potential promising target for cancer treatment. Several FGFR inhibitors are currently under development. Initial preclinical results have translated into limited successful clinical responses when first-generation, nonspecific FGFR inhibitors were evaluated in patients. The future development of selective and unselective FGFR inhibitors will rely on a better understanding of the tissue-specific role of FGFR signaling and identification of biomarkers to select those patients who will benefit the most from these drugs. Further studies are warranted to establish the predictive significance of the different FGFR-aberrations and to incorporate them into clinical algorithms, now that second-generation, selective FGFR inhibitors exist. PMID:26615127

  3. miR-17-92 fine-tunes MYC expression and function to ensure optimal B cell lymphoma growth

    PubMed Central

    Mihailovich, Marija; Bremang, Michael; Spadotto, Valeria; Musiani, Daniele; Vitale, Elena; Varano, Gabriele; Zambelli, Federico; Mancuso, Francesco M.; Cairns, David A.; Pavesi, Giulio; Casola, Stefano; Bonaldi, Tiziana

    2015-01-01

    The synergism between c-MYC and miR-17-19b, a truncated version of the miR-17-92 cluster, is well-documented during tumor initiation. However, little is known about miR-17-19b function in established cancers. Here we investigate the role of miR-17-19b in c-MYC-driven lymphomas by integrating SILAC-based quantitative proteomics, transcriptomics and 3′ untranslated region (UTR) analysis upon miR-17-19b overexpression. We identify over one hundred miR-17-19b targets, of which 40% are co-regulated by c-MYC. Downregulation of a new miR-17/20 target, checkpoint kinase 2 (Chek2), increases the recruitment of HuR to c-MYC transcripts, resulting in the inhibition of c-MYC translation and thus interfering with in vivo tumor growth. Hence, in established lymphomas, miR-17-19b fine-tunes c-MYC activity through a tight control of its function and expression, ultimately ensuring cancer cell homeostasis. Our data highlight the plasticity of miRNA function, reflecting changes in the mRNA landscape and 3′ UTR shortening at different stages of tumorigenesis. PMID:26555894

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

    PubMed

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

    2011-09-01

    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

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

    SciTech Connect

    Lee, Yi-Mu; Yang, Hsi-Wen

    2011-03-15

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

  6. 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

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

    1994-01-01

    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. PMID:7929004

  7. Optimization of an in vitro bioassay to monitor growth and formation of myotubes in real time.

    PubMed

    Murphy, Sylvia M; Kiely, Maeve; Jakeman, Philip M; Kiely, Patrick A; Carson, Brian P

    2016-06-01

    The importance of growth and maintenance of skeletal muscle is vital for long term health and quality of life. Appropriate nutrition with specific bioactivities relevant to the functionalities of tissues such as skeletal muscle, can assist in maintaining and promoting adaptive responses to biological and environmental stresses which prevent muscle atrophy and promote hypertrophy. The aim of this investigation was to develop a novel in vitro cell-based electric impedance assay to study myoblast to myotube formation on the real time cell analysis (RTCA) platform (xCELLigence™, ACEA) and to validate the system by testing myotube responses to hypertrophic stimuli. C2C12 myoblasts were proliferated until 70% confluent in Dulbecco's Modified Eagles Medium (DMEM) (10% FBS) and subsequently differentiated to myotubes over 8 days in DMEM [2% horse serum (HS)]. Changes in cell behaviour and adhesion properties were monitored by measuring impedance via interdigitated microelectrodes in the base of E-16 cell culture dishes. To establish the suitability of this assay to monitor nutrient regulation of muscle hypertrophy, leucine, a known potent regulator of MPS was then supplemented to the fully formed myotubes in physiologically relevant conditions-0.20 mM, 0.40 mM, 0.6 mM, 0.8 mM and above 1.0 mM, 1.5 mM, 2.0 mM and impedance subsequently monitored. Parallel experiments highlighting alterations in myotube thickness, muscle protein synthesis (MPS) (mammalian target of rapamycin; mTOR) and differentiation (myogenin) were conducted to support RTCA bioassay findings. This in vitro bioassay can be used to monitor skeletal muscle behaviour and identify nutrient compounds with bioactivities promoting skeletal muscle hypertrophy, reducing muscle atrophy and thus inform the development of novel nutrient formulations for the maintenance of skeletal muscle. PMID:27009307

  8. School achievement in treated PKU children.

    PubMed

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

    1989-12-01

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

  9. 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

    PubMed Central

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

    2009-01-01

    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 the synthetic Insulin like Growth Factor 1 gene (IGF-1s, 60% AT) was observed in transformed E. coli. However, no native IGF-1 gene (IGF-1n, 41% AT) product was detected in the western blots in E. coli. Site-specific integration of the transgenes into the tobacco chloroplast genome was confirmed after transformation using PCR. Southern blot analysis confirmed that the transgenic lines were homoplasmic. The transgenic plant lines had IGF-1s expression levels of 11.3% of total soluble protein (TSP). The IGF-1n plants contained 9.5% TSP as IGF-1n, suggesting that the chloroplast translation machinery is more flexible than E. coli in codon preference and usage. The expression of IGF-1 was increased up to 32% TSP under continuous illumination by the chloroplast light regulatory elements. IgG-Sepharose affinity column chromatographic separation of Z domain containing chloroplast derived IGF-1 protein, single and two dimensional electrophoresis methods and mass spectrometer analysis confirmed the identity of human IGF-1 in transgenic chloroplasts. Two spots analyzed from 2-D focusing/phoresis acrylamide gel showed the correct amino acid sequence of human IGF-1 and the S. aureus Z-tag. Cell proliferation assays in human HU-3 cells demonstrated the biological activity of chloroplast derived IGF-1 even in the presence of the S. aureus Z tag. Conclusion This study demonstrates that the human Insulin like Growth Factor-1 expressed in transgenic chloroplasts is identical to the native protein and is fully functional. The ability to use plant chloroplasts as bioreactors to generate proteins of great economic value that retain their biological activity is an exciting and achievable goal that appears to be within our grasp. PMID:19344517

  10. Self-Beliefs and Student Goal Achievement

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  11. Modern Elementary Science Curricula and Student Achievement.

    ERIC Educational Resources Information Center

    Smith, Ben Afton

    Comparisons of the growth in science achievement of 2,000 elementary science students in six elementary science programs used in Southwestern Michigan were made. Relationships between students' ranking in class, the type of school, sex and growth in achievement were sought, as well as relationships among teacher variables (pre-service science…

  12. Use of culture geometry to control hypoxia-induced vascular endothelial growth factor secretion from adipose-derived stem cells: optimizing a cell-based approach to drive vascular growth.

    PubMed

    Skiles, Matthew L; Sahai, Suchit; Rucker, Lindsay; Blanchette, James O

    2013-11-01

    Adipose-derived stem cells (ADSCs) possess potent angiogenic properties and represent a source for cell-based approaches to delivery of bioactive factors to drive vascularization of tissues. Hypoxic signaling appears to be largely responsible for triggering release of these angiogenic cytokines, including vascular endothelial growth factor (VEGF). Three-dimensional (3D) culture may promote activation of hypoxia-induced pathways, and has furthermore been shown to enhance cell survival by promoting cell-cell interactions while increasing angiogenic potential. However, the development of hypoxia within ADSC spheroids is difficult to characterize. In the present study, we investigated the impact of spheroid size on hypoxia-inducible transcription factor (HIF)-1 activity in spheroid cultures under atmospheric and physiological oxygen conditions using a fluorescent marker. Hypoxia could be induced and modulated by controlling the size of the spheroid; HIF-1 activity increased with spheroid size and with decreasing external oxygen concentration. Furthermore, VEGF secretion was impacted by the hypoxic status of the culture, increasing with elevated HIF-1 activity, up to the point at which viability was compromised. Together, these results suggest the ability to use 3D culture geometry as a means to control output of angiogenic factors from ADSCs, and imply that at a particular environmental oxygen concentration an optimal culture size for cytokine production exists. Consideration of culture geometry and microenvironmental conditions at the implantation site will be important for successful realization of ADSCs as a pro-angiogenic therapy. PMID:23668629

  13. Synthesis, growth, optimization, bulk SR method growth, fabrication of indigenous optical element and anisotropic studies on guanidinium L-monohydrogen tartrate (GuHT) single crystal for nonlinear optical device applications

    NASA Astrophysics Data System (ADS)

    Vivek, P.; Roop Kumar, R.; Murugakoothan, P.

    2015-02-01

    An organic NLO material guanidinium L-monohydrogen tartrate (GuHT) was grown by the slow evaporation technique using water as a solvent. The solubility and meta stable zone width was determined. The GuHT crystal belongs to orthorhombic system with noncentrosymmetric space group P212121. The morphology of the GuHT crystal was studied. The most prominent plane (0 0 1) was encouraged to grow in unidirection by Sankaranarayanan-Ramasamy (SR) method using water as a solvent. The growth conditions were optimized. The transparent GuHT single crystal of maximum width 15 mm and length 101 mm was obtained by employing SR method. The grown crystal was subjected to high resolution X-ray diffraction, UV-vis-NIR transmittance, refractive index, hardness, laser damage threshold and birefringence studies in different planes. The particle size dependent second harmonic generation efficiency for guanidinium L-monohydrogen tartrate was evaluated by Kurtz-Perry powder method using Nd:YAG laser, which established the existence of phase matching. The second harmonic generation (SHG) of GuHT crystal was investigated by the SHG Maker fringes technique.

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

    PubMed

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

    2011-01-01

    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

  15. Bridgman crystal growth

    NASA Technical Reports Server (NTRS)

    Carlson, Frederick

    1990-01-01

    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.

  16. Pyridodiazepine amines are selective therapeutic agents for helicobacter pylori by suppressing growth through inhibition of glutamate racemase but are predicted to require continuous elevated levels in plasma to achieve clinical efficacy.

    PubMed

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

    2015-04-01

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

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

    PubMed Central

    Kutschke, Amy; Newman, Joseph V.; Rooney, Michael T.; Yang, Wei; Cederberg, Christer

    2015-01-01

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

  18. Graded Achievement, Tested Achievement, and Validity

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Twenty-eight studies of grades, over a century, were reviewed using the argument-based approach to validity suggested by Kane as a theoretical framework. The review draws conclusions about the meaning of graded achievement, its relation to tested achievement, and changes in the construct of graded achievement over time. "Graded…

  19. Prospective Optimization

    PubMed Central

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

    2014-01-01

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

  20. Gear optimization

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    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.

  1. InAs nanowire growth modes on Si (111) by gas source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Robson, M. T.; LaPierre, R. R.

    2016-02-01

    InAs nanowires (NWs) were grown on silicon substrates by gas source molecular beam epitaxy using five different growth modes: (1) Au-assisted growth, (2) positioned (patterned) Au-assisted growth, (3) Au-free growth, (4) positioned Au-assisted growth using a patterned oxide mask, and (5) Au-free selective-area epitaxy (SAE) using a patterned oxide mask. Optimal growth conditions (temperature, V/III flux ratio) were identified for each growth mode for control of NW morphology and vertical NW yield. The highest yield (72%) was achieved with the SAE method at a growth temperature of 440 °C and a V/III flux ratio of 4. Growth mechanisms are discussed for each of the growth modes.

  2. Optimized growth of lattice-matched In{sub x}Al{sub 1-x}N/GaN heterostructures by molecular beam epitaxy

    SciTech Connect

    Schmult, S.; Siegrist, T.; Sergent, A. M.; Manfra, M. J.; Molnar, R. J.

    2007-01-08

    The authors present a systematic study on the growth of the ternary compound In{sub x}Al{sub 1-x}N by molecular beam epitaxy. This work concentrates on In mole fractions x around 0.17, as this composition is in-plane lattice matched to GaN. At a growth temperature of 540 degree sign C, high quality material was obtained using a total metal to nitrogen flux ratio of {approx}1. Using these growth parameters, high quality GaN/InAlN superlattices were obtained without growth interruptions.

  3. Posttraumatic growth in former Vietnam prisoners of war.

    PubMed

    Feder, Adriana; Southwick, Steven M; Goetz, Raymond R; Wang, Yanping; Alonso, Angelique; Smith, Bruce W; Buchholz, Katherine R; Waldeck, Tracy; Ameli, Rezvan; Moore, Jeffrey; Hain, Robert; Charney, Dennis S; Vythilingam, Meena

    2008-01-01

    This study examined posttraumatic growth in 30 male veterans captured and held as prisoners of war during the Vietnam War. Participants were assessed with structured diagnostic interviews administered by trained clinicians as well as with the Posttraumatic Growth Inventory (PTGI) and other questionnaires measuring dispositional optimism, religious coping, social supports, and purpose in life. Mean age (standard deviation-SD) of participants was 66.7 (6.0) years. Mean total PTGI score (SD) was 66.3 (17.5), indicating a moderate degree of posttraumatic growth. The most strongly endorsed items corresponded to the Appreciation of Life and Personal Strength factors. The group as a whole was optimistic and reported moderate use of positive religious coping. Posttraumatic growth did not significantly differ in repatriates with and without psychopathology, but it was significantly positively correlated with dispositional optimism. In the final regression model, length of captivity and optimism were significant predictors of posttraumatic growth. Our findings confirm that it is possible to achieve long-lasting personal growth even in the face of prolonged extreme adversity. Prospective studies are needed to further evaluate whether pre-existing traits such as optimism can predict growth after trauma. PMID:19152285

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  6. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  7. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Meyyappan, M.

    2004-01-01

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

  8. Comparing Science Achievement Constructs: Targeted and Achieved

    ERIC Educational Resources Information Center

    Ferrara, Steve; Duncan, Teresa

    2011-01-01

    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.…

  9. Motivation and School Achievement.

    ERIC Educational Resources Information Center

    Maehr, Martin L.; Archer, Jennifer

    Addressing the question, "What can be done to promote school achievement?", this paper summarizes the literature on motivation relating to classroom achievement and school effectiveness. Particular attention is given to how values, ideology, and various cultural patterns impinge on classroom performance and serve to enhance motivation to achieve.…

  10. The Malic Enzyme Is Required for Optimal Photoautotrophic Growth of Synechocystis sp. Strain PCC 6803 under Continuous Light but Not under a Diurnal Light Regimen

    PubMed Central

    Bricker, Terry M.; Zhang, Shulu; Laborde, Susan M.; Mayer, Paul R.; Frankel, Laurie K.; Moroney, James V.

    2004-01-01

    A mutation was recovered in the slr0721 gene, which encodes the decarboxylating NADP+-dependent malic enzyme in the cyanobacterium Synechocystis sp. strain PCC 6803, yielding the mutant 3WEZ. Under continuous light, 3WEZ exhibits poor photoautotrophic growth while growing photoheterotrophically on glucose at rates nearly indistinguishable from wild-type rates. Interestingly, under diurnal light conditions (12 h of light and 12 h of dark), normal photoautotrophic growth of the mutant is completely restored. PMID:15547288

  11. Growth optimization of InAs/GaAs quantum dots and performance enhancement of a GaAs tunnel diode by embedding quantum dots for solar cell application

    NASA Astrophysics Data System (ADS)

    Park, K. W.; Kang, S. J.; Ravindran, Sooraj; Min, J. W.; Lee, S. K.; Lee, Y. T.

    2015-07-01

    We report the performance enhancement of a molecular beam epitaxy grown GaAs tunnel diode embedded with InAs quantum dots (QDs) for tandem solar cell application, and characterization of tunnel diodes embedded with InAs QDs grown with different growth parameters. Prior to the growth and fabrication of the tunnel diode, InAs QDs were grown under different growth durations and temperatures. The InAs QD samples grown in a temperature range from 480 to 520 °C for a duration of 32 s showed the highest areal fill fraction by InAs QDs. Tunnel diodes embedded with InAs QDs that were grown at various growth conditions were fabricated and characterized. We found that the tunnel diode embedded with InAs QD grown at 520 °C showed the highest peak tunnel current density among all the samples. The enhanced performance of the InAs QD embedded tunnel diode is attributed to the large areal fill fraction produced by the presence of large InAs QDs having high density, which are formed at sufficiently high growth temperature and long growth duration.

  12. Fully automated molecular biology routines on a plasmid-based functional proteomic workcell: Evaluation and Characterization of Yeast Strains Optimized for Growth on Xylose Expressing "Stealth" Insecticidal Peptides.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optimization of genes important to production of fuel ethanol from hemicellulosic biomass for use in developing improved commercial yeast strains is necessary to meet the rapidly expanding need for ethanol. The United States Department of Agriculture has developed a fully automated platform for mol...

  13. Taurine supplementation of plant derived protein 1 and n-3 fatty acids are critical for optimal growth and development of cobia, rachycentron canadum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined growth performance and lipid content in juvenile cobia, Rachycentron canadum, fed a taurine supplemented (1.5%), plant protein based diet with two fish oil replacements. The first fish oil replacement was a thraustochytrid meal (TM+SOY) plus soybean oil (~9% CL) and the second was a cano...

  14. Optimization aspects of carcinogenesis.

    TOXLINE Toxicology Bibliographic Information

    Brutovsky B; Horvath D

    2010-05-01

    Any process in which competing solutions replicate with errors and numbers of their copies depend on their respective fitnesses is the evolutionary optimization process. As during carcinogenesis mutated genomes replicate according to their respective qualities, carcinogenesis obviously qualifies as the evolutionary optimization process and conforms to common mathematical basis. The optimization view accents statistical nature of carcinogenesis proposing that during it the crucial role is actually played by the allocation of trials. Optimal allocation of trials requires reliable schemas' fitnesses estimations which necessitate appropriate, fitness landscape dependent, statistics of population. In the spirit of the applied conceptual framework, features which are known to decrease efficiency of any evolutionary optimization procedure (or inhibit it completely) are anticipated as "therapies" and reviewed. Strict adherence to the evolutionary optimization framework leads us to some counterintuitive implications which are, however, in agreement with recent experimental findings, such as sometimes observed more aggressive and malignant growth of therapy surviving cancer cells.

  15. Optimization aspects of carcinogenesis.

    PubMed

    Brutovsky, B; Horvath, D

    2010-05-01

    Any process in which competing solutions replicate with errors and numbers of their copies depend on their respective fitnesses is the evolutionary optimization process. As during carcinogenesis mutated genomes replicate according to their respective qualities, carcinogenesis obviously qualifies as the evolutionary optimization process and conforms to common mathematical basis. The optimization view accents statistical nature of carcinogenesis proposing that during it the crucial role is actually played by the allocation of trials. Optimal allocation of trials requires reliable schemas' fitnesses estimations which necessitate appropriate, fitness landscape dependent, statistics of population. In the spirit of the applied conceptual framework, features which are known to decrease efficiency of any evolutionary optimization procedure (or inhibit it completely) are anticipated as "therapies" and reviewed. Strict adherence to the evolutionary optimization framework leads us to some counterintuitive implications which are, however, in agreement with recent experimental findings, such as sometimes observed more aggressive and malignant growth of therapy surviving cancer cells. PMID:19906492

  16. How much detail and accuracy is required in plant growth sub-models to address questions about optimal management strategies in agricultural systems?

    PubMed Central

    Renton, Michael

    2011-01-01

    Background and aims Simulations that integrate sub-models of important biological processes can be used to ask questions about optimal management strategies in agricultural and ecological systems. Building sub-models with more detail and aiming for greater accuracy and realism may seem attractive, but is likely to be more expensive and time-consuming and result in more complicated models that lack transparency. This paper illustrates a general integrated approach for constructing models of agricultural and ecological systems that is based on the principle of starting simple and then directly testing for the need to add additional detail and complexity. Methodology The approach is demonstrated using LUSO (Land Use Sequence Optimizer), an agricultural system analysis framework based on simulation and optimization. A simple sensitivity analysis and functional perturbation analysis is used to test to what extent LUSO's crop–weed competition sub-model affects the answers to a number of questions at the scale of the whole farming system regarding optimal land-use sequencing strategies and resulting profitability. Principal results The need for accuracy in the crop–weed competition sub-model within LUSO depended to a small extent on the parameter being varied, but more importantly and interestingly on the type of question being addressed with the model. Only a small part of the crop–weed competition model actually affects the answers to these questions. Conclusions This study illustrates an example application of the proposed integrated approach for constructing models of agricultural and ecological systems based on testing whether complexity needs to be added to address particular questions of interest. We conclude that this example clearly demonstrates the potential value of the general approach. Advantages of this approach include minimizing costs and resources required for model construction, keeping models transparent and easy to analyse, and ensuring the model is well suited to address the question of interest. PMID:22476477

  17. Achieving real-time performance in FIESTA

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    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.

  18. Advanced Czochralski ingot growth

    SciTech Connect

    Lane, R.L.

    1982-04-01

    A summary of advanced Cz ingot-growth activities is presented. Five ingots (totalling 150 kg) were grown from one crucible by use of chunk silicon replenishment between ingot pulls. The cost of the ingot growth was reduced from $80/kg (conventional Cz growth) to $20/kg. Further improvements can be made by achieving a better understanding of crystalline silicon growth and the influence on growth of contaminants from the atmosphere and/or the crucible. This should lead to a higher percentage of monocrystalline growth and possible increased growth rates.

  19. Advanced Czohcralski ingot growth

    NASA Astrophysics Data System (ADS)

    Lane, R. L.

    1982-04-01

    A summary of advanced Cz ingot-growth activities is presented. Five ingots (totalling 150 kg) were grown from one crucible by use of chunk silicon replenishment between ingot pulls. The cost of the ingot growth was reduced from $80/kg (conventional Cz growth) to $20/kg. Further improvements can be made by achieving a better understanding of crystalline silicon growth and the influence on growth of contaminants from the atmosphere and/or the crucible. This should lead to a higher percentage of monocrystalline growth and possible increased growth rates.

  20. General Achievement Trends: Arkansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  1. General Achievement Trends: Tennessee

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  2. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

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

  3. General Achievement Trends: Michigan

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  4. General Achievement Trends: Kentucky

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  5. General Achievement Trends: Iowa

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  6. General Achievement Trends: Oregon

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  7. General Achievement Trends: Colorado

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  8. General Achievement Trends: Georgia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  9. General Achievement Trends: Kansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  10. General Achievement Trends: Oklahoma

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  11. General Achievement Trends: Hawaii

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  12. General Achievement Trends: Maryland

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  13. General Achievement Trends: Texas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  14. General Achievement Trends: Idaho

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  15. General Achievement Trends: Massachusetts

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  16. General Achievement Trends: Alabama

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  17. General Achievement Trends: Florida

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  18. General Achievement Trends: Virginia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  19. General Achievement Trends: Nebraska

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  20. General Achievement Trends: Maine

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  1. Assessing Handwriting Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    2002-01-01

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

  2. Achieving Perspective Transformation.

    ERIC Educational Resources Information Center

    Nowak, Jens

    Perspective transformation is a consciously achieved state in which the individual's perspective on life is transformed. The new perspective serves as a vantage point for life's actions and interactions, affecting the way life is lived. Three conditions are basic to achieving perspective transformation: (1) "feeling" experience, i.e., getting in

  3. Achievement Test Program.

    ERIC Educational Resources Information Center

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

    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

  4. Music and Achievement.

    ERIC Educational Resources Information Center

    Smith, Ben A.; Davidson, Charles W.

    1991-01-01

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

  5. Wechsler Individual Achievement Test.

    ERIC Educational Resources Information Center

    Taylor, Ronald L.

    1999-01-01

    This article describes the Wechsler Individual Achievement Test, a comprehensive measure of achievement for individuals in grades K-12. Eight subtests assess mathematics reasoning, spelling, reading comprehension, numerical operations, listening comprehension, oral expression, and written expression. Its administration, standardization,…

  6. States Address Achievement Gaps.

    ERIC Educational Resources Information Center

    Christie, Kathy

    2002-01-01

    Summarizes 2 state initiatives to address the achievement gap: North Carolina's report by the Advisory Commission on Raising Achievement and Closing Gaps, containing an 11-point strategy, and Kentucky's legislation putting in place 10 specific processes. The North Carolina report is available at www.dpi.state.nc.us.closingthegap; Kentucky's

  7. Achieving Public Schools

    ERIC Educational Resources Information Center

    Abowitz, Kathleen Knight

    2011-01-01

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

  8. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

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

  9. Heritability of Creative Achievement

    ERIC Educational Resources Information Center

    Piffer, Davide; Hur, Yoon-Mi

    2014-01-01

    Although creative achievement is a subject of much attention to lay people, the origin of individual differences in creative accomplishments remain poorly understood. This study examined genetic and environmental influences on creative achievement in an adult sample of 338 twins (mean age = 26.3 years; SD = 6.6 years). Twins completed the Creative…

  10. Optimization of 2,3-butanediol production by Klebsiella oxytoca through oxygen transfer rate control

    SciTech Connect

    Beronio, P.B. Jr. . Amoco Research Center); Tsao, G.T. . Lab. of Renewable Resources Engineering)

    1993-12-01

    Production of 2,3-butanediol by Klebsiella oxytoca is influenced by the degree of oxygen limitation. During batch culture studies, two phases of growth are observed: energy-coupled growth, during which cell growth and oxygen supply are coupled; and, energy-uncoupled growth, which arises when the degree of oxygen limitation reaches a critical value. Optimal 2,3-butanediol productivity occurs during the energy-coupled growth phase. In this article, a control system which maintains the batch culture at a constant level of oxygen limitation in the energy-coupled growth regime has been designed. Control, which involves feedback control on the oxygen transfer coefficient, is achieved by continually increasing the partial pressure of oxygen in the feed gas, which in turn continually increases the oxygen transfer rate. Control has resulted in a balanced state of growth, a repression of ethanol formation, and an increase in 2,3-butanediol productivity of 18%.

  11. Hemisphericity and student achievement.

    PubMed

    Yeap, L L

    1989-10-01

    Hemispheric preference, the newest element of learning style, refers to the tendency of a person to use one side of the brain to perceive and function more than the other. The objective of the study was to investigate the psychological domain of learning styles in terms of the hemispheric patterns of Singapore Secondary Two students in the three achievement levels, namely Normal (low achievers), Express (average achievers), and Special (high achievers). Using the Cognitive Laterality Battery (Gordon, 1986) to measure the students' hemispheric dominance, the study found that it is in the psychological domain of the students' learning styles, in terms of their hemispheric dominance that the Secondary Two students in the three achievement levels are distinctly different. PMID:2583937

  12. Improving blood pressure control: increase the dose of diuretic or switch to a fixed-dose angiotensin receptor blocker/diuretic? the valsartan hydrochlorothiazide diuretic for initial control and titration to achieve optimal therapeutic effect (Val-DICTATE) trial.

    PubMed

    White, William B; Calhoun, David A; Samuel, Rita; Taylor, Addison A; Zappe, Dion H; Purkayastha, Das

    2008-06-01

    To assess the strategy of increasing the dose of a diuretic compared with using an angiotensin receptor blocker in combination with a diuretic, the authors performed a multicenter, randomized, parallel group trial in hypertensive patients (baseline blood pressure [BP], 153/97 mm Hg) whose BP remained uncontrolled on initial low-dose diuretic monotherapy (hydrochlorothiazide [HCTZ] 12.5 mg Hg). Patients with stage 1 and 2 hypertension were randomized to treatment with valsartan/HCTZ (160/12.5 mg) or to doubling of the HCTZ dose (25 mg). The primary end point was the percentage of patients whose clinic BP values were <140/90 mm Hg following 4 weeks of double-blind therapy. A significantly higher proportion (P<.001) of hypertensive patients met BP control levels in the valsartan/HCTZ (160/12.5 mg) group compared with the HCTZ 25 mg group (37% vs 16%). Changes from baseline in BP were significantly greater (P<.001) for both systolic BP and diastolic BP in the combination therapy arm compared with the diuretic monotherapy arm (-12. 4/-7.5 mm Hg in valsartan/HCTZ 160/12.5 mg group vs -5.6/-2.1 mm Hg in HCTZ 25 mg group). Tolerability and adverse events were similar in the 2 treatment groups. This study suggests that in the management of hypertension, utilizing an angiotensin receptor blocker/diuretic combination was more effective in lowering BP and achieving BP goals when compared with increasing the dose of the diuretic. PMID:18550935

  13. Optimizing the water chemistry of the Novovoronezh NPP Units 3 and 4 to prevent growth of coolant pressure difference across the reactor

    NASA Astrophysics Data System (ADS)

    Kritskii, V. G.; Rodionov, Yu. A.; Berezina, I. G.; Zelenina, E. V.; Gavrilov, A. V.; Vitkovskii, S. L.; Shchedrin, M. G.; Galanin, A. V.; Gorburov, V. I.

    2014-02-01

    For a few fuel campaigns in the first years of their extended service life, the Novovoronezh NPP Units 3 and 4 had to operate with a limited reactor thermal power output due to constraints imposed on certain parameters of the reactor core. The decrease of thermal power output during a campaign was accompanied by a growth of pressure difference across the reactor caused by accumulation of deposits in the fuel assemblies, which in turn led to a growth in the number of leaky fuel rods. Compensating measures were implemented based on the results obtained from the performed investigations and modeling of corrosion product mass transfer processes, which in the final analysis made it possible to minimize the accumulation of deposits in fuel assemblies and loss of fuel rod tightness, and to exclude the need to limit the reactor thermal power as demanded by constraints imposed on the reactor core parameters.

  14. An optimized dosing regimen of cimaglermin (neuregulin 1β3, glial growth factor 2) enhances molecular markers of neuroplasticity and functional recovery after permanent ischemic stroke in rats.

    PubMed

    Iaci, Jennifer F; Parry, Tom J; Huang, Zhihong; Pavlopoulos, Elias; Finklestein, Seth P; Ren, Jingmei; Caggiano, Anthony

    2016-03-01

    Cimaglermin (neuregulin 1β3, glial growth factor 2) is a neuregulin growth factor family member in clinical development for chronic heart failure. Previously, in a permanent middle cerebral artery occlusion (pMCAO) rat stroke model, systemic cimaglermin treatment initiated up to 7 days after ischemia onset promoted recovery without reduced lesion volume. Presented here to extend the evidence are two studies that use a rat stroke model to evaluate the effects of cimaglermin dose level and dose frequency initiated 24 hr after pMCAO. Forelimb- and hindlimb-placing scores (proprioceptive behavioral tests), body-swing symmetry, and infarct volume were compared between treatment groups (n = 12/group). Possible mechanisms underlying cimaglermin-mediated neurologic recovery were examined through axonal growth and synapse formation histological markers. Cimaglermin was evaluated over a wider dose range (0.02, 0.1, or 1.0 mg/kg) than doses previously shown to be effective but used the same dosing regimen (2 weeks of daily intravenous administration, then 1 week without treatment). The dose-frequency study used the dose-ranging study's most effective dose (1.0 mg/kg) to compare daily, once per week, and twice per week dosing for 3 weeks (then 1 week without treatment). Dose- and frequency-dependent functional improvements were observed with cimaglermin without reduced lesion volume. Cimaglermin treatment significantly increased growth-associated protein 43 expression in both hemispheres (particularly somatosensory and motor cortices) and also increased synaptophysin expression. These data indicate that cimaglermin enhances recovery after stroke. Immunohistochemical changes were consistent with axonal sprouting and synapse formation but not acute neuroprotection. Cimaglermin represents a potential clinical development candidate for ischemic stroke treatment. © 2015 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc. PMID:26660233

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

    ERIC Educational Resources Information Center

    Geiser, Saul

    2009-01-01

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

  16. [Achievement of therapeutic objectives].

    PubMed

    Mantilla, Teresa

    2014-07-01

    Therapeutic objectives for patients with atherogenic dyslipidemia are achieved by improving patient compliance and adherence. Clinical practice guidelines address the importance of treatment compliance for achieving objectives. The combination of a fixed dose of pravastatin and fenofibrate increases the adherence by simplifying the drug regimen and reducing the number of daily doses. The good tolerance, the cost of the combination and the possibility of adjusting the administration to the patient's lifestyle helps achieve the objectives for these patients with high cardiovascular risk. PMID:25043543

  17. Optimization of experimental and modelling parameters for the differentiation of beverage spoiling yeasts by Matrix-Assisted-Laser-Desorption/Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in response to varying growth conditions.

    PubMed

    Usbeck, Julia C; Kern, Carola C; Vogel, Rudi F; Behr, Jürgen

    2013-12-01

    The growth of spoiling yeasts in beverages results in reduced quality, economic and image losses. Therefore, biochemical and DNA-based identification methods have been developed but are mostly time-consuming and laborious. Matrix-Assisted-Laser-Desorption/Ionization-Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) could deliver discriminative peptide mass fingerprints within minutes and could thus be a rapid and reliable tool for identification and differentiation. However, routine analysis of yeasts by MALDI-TOF MS is yet impaired by low reproducibility and effects of different physiological states of organisms on the reliability of the identification method are still controversial. The aim of this study was to optimize sample preparation and measurement parameterization using three spoilage yeasts (Saccharomyces cerevisiae var. diastaticus, Wickerhamomyces anomalus and Debaryomyces hansenii). The influence of environmental or physiological parameters including oxygen availability, different nutrients, cell density and growth phase were analysed and revealed small differences in mass fingerprints. Yeasts grown in the presence or absence of oxygen were precisely differentiated along these differences in mass fingerprints and a crude classification of growth phase was possible. Cell concentration did not affect the spectra distinctly, neither qualitatively nor quantitatively, and an influence of available nutrients could not be measured in each case. However, core mass peaks remained constant under all tested conditions enabling reliable identification. PMID:24010620

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

    PubMed

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

    2013-09-01

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

  19. Student Achievement and Motivation

    ERIC Educational Resources Information Center

    Flammer, Gordon H.; Mecham, Robert C.

    1974-01-01

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

  20. Achieving Salary Equity

    ERIC Educational Resources Information Center

    Nevill, Dorothy D.

    1975-01-01

    Three techniques are outlined for use by higher education institutions to achieve salary equity: salary prediction (using various statistical procedures), counterparting (comparing salaries of persons of similar rank), and grievance procedures. (JT)

  1. An optimized dosing regimen of cimaglermin (neuregulin 1β3, glial growth factor 2) enhances molecular markers of neuroplasticity and functional recovery after permanent ischemic stroke in rats

    PubMed Central

    Parry, Tom J.; Huang, Zhihong; Pavlopoulos, Elias; Finklestein, Seth P.; Ren, Jingmei; Caggiano, Anthony

    2015-01-01

    Cimaglermin (neuregulin 1β3, glial growth factor 2) is a neuregulin growth factor family member in clinical development for chronic heart failure. Previously, in a permanent middle cerebral artery occlusion (pMCAO) rat stroke model, systemic cimaglermin treatment initiated up to 7 days after ischemia onset promoted recovery without reduced lesion volume. Presented here to extend the evidence are two studies that use a rat stroke model to evaluate the effects of cimaglermin dose level and dose frequency initiated 24 hr after pMCAO. Forelimb‐ and hindlimb‐placing scores (proprioceptive behavioral tests), body‐swing symmetry, and infarct volume were compared between treatment groups (n = 12/group). Possible mechanisms underlying cimaglermin‐mediated neurologic recovery were examined through axonal growth and synapse formation histological markers. Cimaglermin was evaluated over a wider dose range (0.02, 0.1, or 1.0 mg/kg) than doses previously shown to be effective but used the same dosing regimen (2 weeks of daily intravenous administration, then 1 week without treatment). The dose‐frequency study used the dose‐ranging study's most effective dose (1.0 mg/kg) to compare daily, once per week, and twice per week dosing for 3 weeks (then 1 week without treatment). Dose‐ and frequency‐dependent functional improvements were observed with cimaglermin without reduced lesion volume. Cimaglermin treatment significantly increased growth‐associated protein 43 expression in both hemispheres (particularly somatosensory and motor cortices) and also increased synaptophysin expression. These data indicate that cimaglermin enhances recovery after stroke. Immunohistochemical changes were consistent with axonal sprouting and synapse formation but not acute neuroprotection. Cimaglermin represents a potential clinical development candidate for ischemic stroke treatment. © 2015 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc. PMID:26660233

  2. The Cytoplasmic Carbonic Anhydrases βCA2 and βCA4 Are Required for Optimal Plant Growth at Low CO21[OPEN

    PubMed Central

    Quebedeaux, Jennifer C.; Longstreth, David J.

    2016-01-01

    Carbonic anhydrases (CAs) are zinc metalloenzymes that interconvert CO2 and HCO3−. In plants, both α- and β-type CAs are present. We hypothesize that cytoplasmic βCAs are required to modulate inorganic carbon forms needed in leaf cells for carbon-requiring reactions such as photosynthesis and amino acid biosynthesis. In this report, we present evidence that βCA2 and βCA4 are the two most abundant cytoplasmic CAs in Arabidopsis (Arabidopsis thaliana) leaves. Previously, βCA4 was reported to be localized to the plasma membrane, but here, we show that two forms of βCA4 are expressed in a tissue-specific manner and that the two proteins encoded by βCA4 localize to two different regions of the cell. Comparing transfer DNA knockout lines with wild-type plants, there was no reduction in the growth rates of the single mutants, βca2 and βca4. However, the growth rate of the double mutant, βca2βca4, was reduced significantly when grown at 200 μL L−1 CO2. The reduction in growth of the double mutant was not linked to a reduction in photosynthetic rate. The amino acid content of leaves from the double mutant showed marked reduction in aspartate when compared with the wild type and the single mutants. This suggests the cytoplasmic CAs play an important but not previously appreciated role in amino acid biosynthesis. PMID:26993617

  3. Optimized solar module design

    NASA Technical Reports Server (NTRS)

    Santala, T.; Sabol, R.; Carbajal, B. G.

    1978-01-01

    The minimum cost per unit of power output from flat plate solar modules can most likely be achieved through efficient packaging of higher efficiency solar cells. This paper outlines a module optimization method which is broadly applicable, and illustrates the potential results achievable from a specific high efficiency tandem junction (TJ) cell. A mathematical model is used to assess the impact of various factors influencing the encapsulated cell and packing efficiency. The optimization of the packing efficiency is demonstrated. The effect of encapsulated cell and packing efficiency on the module add-on cost is shown in a nomograph form.

  4. Longitudinal Look at Student Achievement and Psychological Engagement

    ERIC Educational Resources Information Center

    Videen, Cheryl Ann

    2009-01-01

    This study examined relations between students' psychological engagement and academic achievement, as well as between students' psychological engagement and growth in academic achievement. The study also examined if relations between students' psychological engagement and academic growth varied by grade level (elementary school compared to middle

  5. Learning optimal embedded cascades.

    PubMed

    Saberian, Mohammad Javad; Vasconcelos, Nuno

    2012-10-01

    The problem of automatic and optimal design of embedded object detector cascades is considered. Two main challenges are identified: optimization of the cascade configuration and optimization of individual cascade stages, so as to achieve the best tradeoff between classification accuracy and speed, under a detection rate constraint. Two novel boosting algorithms are proposed to address these problems. The first, RCBoost, formulates boosting as a constrained optimization problem which is solved with a barrier penalty method. The constraint is the target detection rate, which is met at all iterations of the boosting process. This enables the design of embedded cascades of known configuration without extensive cross validation or heuristics. The second, ECBoost, searches over cascade configurations to achieve the optimal tradeoff between classification risk and speed. The two algorithms are combined into an overall boosting procedure, RCECBoost, which optimizes both the cascade configuration and its stages under a detection rate constraint, in a fully automated manner. Extensive experiments in face, car, pedestrian, and panda detection show that the resulting detectors achieve an accuracy versus speed tradeoff superior to those of previous methods. PMID:22213762

  6. Population growth and economic growth.

    PubMed

    Narayana, D L

    1984-01-01

    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

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

    PubMed

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

    2014-06-01

    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

  8. Physical vapor transport growth of aluminum nitride

    NASA Astrophysics Data System (ADS)

    Letts, Edward Robert

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  11. Optimization of evaporative cooling

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Bradley, C. C.; Hulet, R. G.

    1997-05-01

    Recent experiments have used forced evaporative cooling to produce Bose-Einstein condensation in dilute gases. The evaporative cooling process can be optimized to provide the maximum phase-space density with a specified number of atoms remaining. We show that this global optimization is approximately achieved by locally optimizing the cooling efficiency at each instant. We discuss how this method can be implemented, and present the results for our 7Li trap. The predicted behavior of the gas is found to agree well with experiment.

  12. Achieving yield gains in wheat.

    PubMed

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

    2012-10-01

    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

  13. Optimal husbandry of hatchling Eastern Indigo Snakes (Drymarchon couperi) during a captive head-start program.

    PubMed

    Wines, Michael P; Johnson, Valerie M; Lock, Brad; Antonio, Fred; Godwin, James C; Rush, Elizabeth M; Guyer, Craig

    2015-01-01

    Optimal husbandry techniques are desirable for any headstart program, but frequently are unknown for rare species. Here we describe key reproductive variables and determine optimal incubation temperature and diet diversity for Eastern Indigo Snakes (Drymarchon couperi) grown in laboratory settings. Optimal incubation temperature was estimated from two variables dependent on temperature, shell dimpling, a surrogate for death from fungal infection, and deviation of an egg from an ovoid shape, a surrogate for death from developmental anomalies. Based on these relationships and size at hatching we determined optimal incubation temperature to be 26°C. Additionally, we used incubation data to assess the effect of temperature on duration of incubation and size of hatchlings. We also examined hatchling diets necessary to achieve optimal growth over a 21-month period. These snakes exhibited a positive linear relationship between total mass eaten and growth rate, when individuals were fed less than 1711 g of prey, and displayed constant growth for individuals exceeding 1711 g of prey. Similarly, growth rate increased linearly with increasing diet diversity up to a moderately diverse diet, followed by constant growth for higher levels of diet diversity. Of the two components of diet diversity, diet evenness played a stronger role than diet richness in explaining variance in hatchling growth. These patterns document that our goal of satiating snakes was achieved for some individuals but not others and that diets in which total grams consumed over the first 21 months of life is distributed equivalently among at least three prey genera yielded the fastest growth rates for hatchling snakes. PMID:25866094

  14. Achieving Zero Net Migration.

    ERIC Educational Resources Information Center

    Mann, Donald

    1984-01-01

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

  15. Bilingualism and Academic Achievement

    ERIC Educational Resources Information Center

    Han, Wen-Jui

    2012-01-01

    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…

  16. CEBAF accelerator achievements

    SciTech Connect

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

    2011-06-01

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

  17. Achievement in Problem Solving

    ERIC Educational Resources Information Center

    Friebele, David

    2010-01-01

    This Action Research Project is meant to investigate the effects of incorporating research-based instructional strategies into instruction and their subsequent effect on student achievement in the area of problem-solving. The two specific strategies utilized are the integration of manipulatives and increased social interaction on a regular basis.

  18. Iowa Women of Achievement.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

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

  19. Reducing the Achievement Gap.

    ERIC Educational Resources Information Center

    McCombs, Barbara L.

    2000-01-01

    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…

  20. Intelligence and Educational Achievement

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  1. The Achievement Club

    ERIC Educational Resources Information Center

    Rogers, Ibram

    2009-01-01

    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…

  2. Essays on Educational Achievement

    ERIC Educational Resources Information Center

    Ampaabeng, Samuel Kofi

    2013-01-01

    This dissertation examines the determinants of student outcomes--achievement, attainment, occupational choices and earnings--in three different contexts. The first two chapters focus on Ghana while the final chapter focuses on the US state of Massachusetts. In the first chapter, I exploit the incidence of famine and malnutrition that resulted to

  3. Home Environment and Achievement.

    ERIC Educational Resources Information Center

    Palmer, Judith A.

    When the quality of the family's influence on the child's academic performance is identified and evaluated, educators can more fully understand and aid the child in the classroom. This survey of research oriented literature probes the relationship between home environment and achievement. Social class, power-structure, child-rearing practices,…

  4. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

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

  5. Schools Achieving Gender Equity.

    ERIC Educational Resources Information Center

    Revis, Emma

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

  6. Explorations in achievement motivation

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.

    1982-01-01

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

  7. SALT and Spelling Achievement.

    ERIC Educational Resources Information Center

    Nelson, Joan

    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…

  8. NCLB: Achievement Robin Hood?

    ERIC Educational Resources Information Center

    Bracey, Gerald W.

    2008-01-01

    In his "Wall Street Journal" op-ed on the 25th of anniversary of "A Nation At Risk", former assistant secretary of education Chester E. Finn Jr. applauded the report for turning U.S. education away from equality and toward achievement. It was not surprising, then, that in mid-2008, Finn arranged a conference to examine the potential "Robin Hood…

  9. School Students' Science Achievement

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  10. Investing in Student Achievement.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    During 1996-97 the Education Commission of the States explored three policy areas in which state efforts to improve student achievement have been increasingly concentrated: early childhood education, teacher quality and stronger connections between the K-12 and postsecondary systems. The study surveyed the scope and intensity of state efforts in…

  11. INTELLIGENCE, PERSONALITY AND ACHIEVEMENT.

    ERIC Educational Resources Information Center

    MUIR, R.C.; AND OTHERS

    A LONGITUDINAL DEVELOPMENTAL STUDY OF A GROUP OF MIDDLE CLASS CHILDREN IS DESCRIBED, WITH EMPHASIS ON A SEGMENT OF THE RESEARCH INVESTIGATING THE RELATIONSHIP OF ACHIEVEMENT, INTELLIGENCE, AND EMOTIONAL DISTURBANCE. THE SUBJECTS WERE 105 CHILDREN AGED FIVE TO 6.3 ATTENDING TWO SCHOOLS IN MONTREAL. EACH CHILD WAS ASSESSED IN THE AREAS OF…

  12. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

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

  13. Achieving Peace through Education.

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

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

  14. Intelligence and Educational Achievement

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  15. Essays on Educational Achievement

    ERIC Educational Resources Information Center

    Ampaabeng, Samuel Kofi

    2013-01-01

    This dissertation examines the determinants of student outcomes--achievement, attainment, occupational choices and earnings--in three different contexts. The first two chapters focus on Ghana while the final chapter focuses on the US state of Massachusetts. In the first chapter, I exploit the incidence of famine and malnutrition that resulted to…

  16. Optimal refrigerator.

    PubMed

    Allahverdyan, Armen E; Hovhannisyan, Karen; Mahler, Guenter

    2010-05-01

    We study a refrigerator model which consists of two n -level systems interacting via a pulsed external field. Each system couples to its own thermal bath at temperatures T h and T c, respectively (θ ≡ T c/T h < 1). The refrigerator functions in two steps: thermally isolated interaction between the systems driven by the external field and isothermal relaxation back to equilibrium. There is a complementarity between the power of heat transfer from the cold bath and the efficiency: the latter nullifies when the former is maximized and vice versa. A reasonable compromise is achieved by optimizing the product of the heat-power and efficiency over the Hamiltonian of the two systems. The efficiency is then found to be bounded from below by [formula: see text] (an analog of the Curzon-Ahlborn efficiency), besides being bound from above by the Carnot efficiency [formula: see text]. The lower bound is reached in the equilibrium limit θ → 1. The Carnot bound is reached (for a finite power and a finite amount of heat transferred per cycle) for ln n > 1. If the above maximization is constrained by assuming homogeneous energy spectra for both systems, the efficiency is bounded from above by ζ CA and converges to it for n > 1. PMID:20866207

  17. Hybrid Swarm Intelligence Optimization Approach for Optimal Data Storage Position Identification in Wireless Sensor Networks

    PubMed Central

    Mohanasundaram, Ranganathan; Periasamy, Pappampalayam Sanmugam

    2015-01-01

    The current high profile debate with regard to data storage and its growth have become strategic task in the world of networking. It mainly depends on the sensor nodes called producers, base stations, and also the consumers (users and sensor nodes) to retrieve and use the data. The main concern dealt here is to find an optimal data storage position in wireless sensor networks. The works that have been carried out earlier did not utilize swarm intelligence based optimization approaches to find the optimal data storage positions. To achieve this goal, an efficient swam intelligence approach is used to choose suitable positions for a storage node. Thus, hybrid particle swarm optimization algorithm has been used to find the suitable positions for storage nodes while the total energy cost of data transmission is minimized. Clustering-based distributed data storage is utilized to solve clustering problem using fuzzy-C-means algorithm. This research work also considers the data rates and locations of multiple producers and consumers to find optimal data storage positions. The algorithm is implemented in a network simulator and the experimental results show that the proposed clustering and swarm intelligence based ODS strategy is more effective than the earlier approaches. PMID:25734182

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

    ERIC Educational Resources Information Center

    McCabe, Molly

    2010-01-01

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

  19. Growth condition optimization and mobility enhancement through prolonging the GaN nuclei coalescence process of AlGaN/AlN/GaN structure

    NASA Astrophysics Data System (ADS)

    He, Xiao-Guang; Zhao, De-Gang; Jiang, De-Sheng; Zhu, Jian-Jun; Chen, Ping; Liu, Zong-Shun; Le, Ling-Cong; Yang, Jing; Li, Xiao-Jing; Zhang, Shu-Ming; Yang, Hui

    2015-09-01

    AlGaN/AlN/GaN structures are grown by metalorganic vapor phase epitaxy on sapphire substrates. Influences of AlN interlayer thickness, AlGaN barrier thickness, and Al composition on the two-dimensional electron gas (2DEG) performance are investigated. Lowering the V/III ratio and enhancing the reactor pressure at the initial stage of the high-temperature GaN layer growth will prolong the GaN nuclei coalescence process and effectively improve the crystalline quality and the interface morphology, diminishing the interface roughness scattering and improving 2DEG mobility. AlGaN/AlN/GaN structure with 2DEG sheet density of 1.19 × 1013 cm-2, electron mobility of 2101 cm2·V-1·s-1, and square resistance of 249 Ω is obtained. Project support by the National Natural Science Foundation of China (Grant Nos. 61474110, 61377020, 61376089, 61223005, and 61176126), the National Science Fund for Distinguished Young Scholars, China (Grant No. 60925017), the One Hundred Person Project of the Chinese Academy of Sciences, and the Basic Research Project of Jiangsu Province, China (Grant No. BK20130362).

  20. Achieving optimal aesthetics using contemporary porcelain materials: a case report.

    PubMed

    Roberts, John; Roberts, Matt

    2004-08-01

    While the selection of an appropriate material contributes to restorative success, a thorough treatment plan with enhanced clinician/technician communication is required to ensure an appropriate and aesthetic result. A concise understanding of the patient's existing condition, desires, and expectations is critical to ensure restorative success. This case presentation demonstrates the clinical and laboratory protocols for the development of predictable, functional, and aesthetic porcelain restorations in treating severely compromised maxillary anterior dentition. PMID:15485162

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

    ERIC Educational Resources Information Center

    Makar, Susan

    2003-01-01

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

  2. Systematic investigation of the growth rate of β-Ga2O3(010) by plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Okumura, Hironori; Kita, Masao; Sasaki, Kohei; Kuramata, Akito; Higashiwaki, Masataka; Speck, James S.

    2014-09-01

    β-Ga2O3(010) homo-epitaxial growth was performed by plasma-assisted molecular beam epitaxy. Under Ga-rich conditions and for growth temperatures above 650 °C, the growth rate was independent of the Ga/O ratio (>1). A high growth rate of 2.2 nm/min for β-Ga2O3(010) was achieved by optimizing the O flux between 650 and 750 °C. Under Ga-rich conditions between growth temperatures of 500-900 °C, smooth surfaces with rms roughness below 1 nm were realized. We found that the slightly Ga-rich conditions between 650 and 750 °C were optimal for β-Ga2O3(010) growth with a smooth surface and a high growth rate.

  3. Quantification of human epidermal growth factor receptor 2 immunohistochemistry using the Ventana Image Analysis System: correlation with gene amplification by fluorescence in situ hybridization: the importance of instrument validation for achieving high (>95%) concordance rate.

    PubMed

    Dennis, Jake; Parsa, Rezvaneh; Chau, Donnie; Koduru, Prasad; Peng, Yan; Fang, Yisheng; Sarode, Venetia Rumnong

    2015-05-01

    The use of computer-based image analysis for scoring human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) has gained a lot of interest recently. We investigated the performance of the Ventana Image Analysis System (VIAS) in HER2 quantification by IHC and its correlation with fluorescence in situ hybridization (FISH). We specifically compared the 3+ IHC results using the manufacturer's machine score cutoffs versus laboratory-defined cutoffs with the FISH assay. Using the manufacturer's 3+ cutoff (VIAS score; 2.51 to 3.5), 181/536 (33.7%) were scored 3+, and FISH was positive in 147/181 (81.2%), 2 (1.1%) were equivocal, and 32 (17.6%) were FISH (-). Using the laboratory-defined 3+ cutoff (VIAS score 3.5), 52 (28.7%) cases were downgraded to 2+, of which 29 (55.7%) were FISH (-), and 23 (44.2%) were FISH (+). With the revised cutoff, there were improvements in the concordance rate from 89.1% to 97.0% and in the positive predictive value from 82.1% to 97.6%. The false-positive rate for 3+ decreased from 9.0% to 0.8%. Six of 175 (3.4%) IHC (-) cases were FISH (+). Three cases with a VIAS score 3.5 showed polysomy of chromosome 17. In conclusion, the VIAS may be a valuable tool for assisting pathologists in HER2 scoring; however, the positive cutoff defined by the manufacturer is associated with a high false-positive rate. This study highlights the importance of instrument validation/calibration to reduce false-positive results. PMID:25602790

  4. Validation and workflow optimization of human epidermal growth factor receptor 2 testing using INFORM HER2 dual-color in situ hybridization.

    PubMed

    Lim, Sung-Jig; Cantillep, Alegria; Carpenter, Philip M

    2013-11-01

    Human epidermal growth factor receptor 2 (HER2) status is useful for predicting response to trastuzumab. Fluorescence in situ hybridization (FISH) for HER2 gene amplification is accurate but limited because of cost, the need for fluorescence microscopy, the limited assessment of histology, and the fading of its signal over time. Dual-color in situ hybridization (Dual ISH) is fully automated, is viewable by bright-field microscopy, has a stable signal, and has separate colors for HER2 and chromosome 17 signals. HER2 immunohistochemistry (IHC), FISH, and Dual ISH were performed on 101 breast cancer cases. Sixteen of 17 cases with 3+ HER2 by IHC showed gene amplification by FISH, and 15 showed amplification by Dual ISH. Three of the 2+ IHC cases were either amplified or equivocal by Dual ISH. None of the IHC-negative cases were amplified by either FISH or Dual ISH. Dual ISH agreed with FISH in 93% of cases. Among the 6 discrepancies, 4 were for an equivocal result for 1 test compared with either a positive or a negative result for the other test. The average differences in readings between Dual ISH and FISH in the discrepant cases were only 0.02, with a range of -1.37 to 1.85. Turnaround time for FISH as a send-out test from test ordering to reporting averaged 8.27 workdays, whereas the turnaround time for Dual ISH performed in-house averaged 4.94 workdays (P < .0000001). Our results indicated that automated Dual ISH is a useful method for evaluating HER2 status in a clinical setting. PMID:24075600

  5. Faculty achievement tracking tool.

    PubMed

    Pettus, Sarah; Reifschneider, Ellen; Burruss, Nancy

    2009-03-01

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

  6. Project ACHIEVE final report

    SciTech Connect

    1997-06-13

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

  7. Optimal temperature control for a structured model of plant cell culture.

    PubMed

    Bailey, C M; Nicholson, H

    1990-02-01

    This article calculates optimal open-loop temperature trajectories that maximize the average rate of product synthesis of a plant cell culture. It uses a previously published five-state mathematical model which describes the growth and product synthesis of a batch plant cell suspension culture of Catharanthus roseus under temperature control. The optimal open-loop temperatures maximize the final product concentration for predefined fermentation periods. A single switch in temperature is shown by computer simulation to be near optimal, with a 22% increase in final product yield over that obtained at the optimal constant temperature. Examination of the achieved final product yield as a function of fermentation period allows this period also to be chosen optimally. This time is reduced from 16 days in the constant temperature case to 12 days in the switched temperature case. PMID:18592517

  8. Dynamic Optimization

    NASA Technical Reports Server (NTRS)

    Laird, Philip

    1992-01-01

    We distinguish static and dynamic optimization of programs: whereas static optimization modifies a program before runtime and is based only on its syntactical structure, dynamic optimization is based on the statistical properties of the input source and examples of program execution. Explanation-based generalization is a commonly used dynamic optimization method, but its effectiveness as a speedup-learning method is limited, in part because it fails to separate the learning process from the program transformation process. This paper describes a dynamic optimization technique called a learn-optimize cycle that first uses a learning element to uncover predictable patterns in the program execution and then uses an optimization algorithm to map these patterns into beneficial transformations. The technique has been used successfully for dynamic optimization of pure Prolog.

  9. Achieving healthy weights.

    PubMed Central

    Kirkland, L.; Anderson, R.

    1993-01-01

    Only 5% of patients dieting to achieve permanent weight loss will be successful and reap the associated health benefits. Ninety-five percent will be unsuccessful. The health implications of failed dieting attempts are numerous and include negative effects on both physical and psychological well-being. Better alternatives to dieting help patients take small, positive, enjoyable steps toward healthy eating, active living, and a positive self-image. PMID:8435552

  10. Hierarchical Optimization Model on Geonetwork

    NASA Astrophysics Data System (ADS)

    Zha, Z.; Jiang, J.; Zhou, X.

    2012-07-01

    In existing construction experience of Spatial Data Infrastructure (SDI), GeoNetwork, as the geographical information integrated solution, is an effective way of building SDI. During GeoNetwork serving as an internet application, several shortcomings are exposed. The first one is that the time consuming of data loading has been considerately increasing with the growth of metadata count. Consequently, the efficiency of query and search service becomes lower. Another problem is that stability and robustness are both ruined since huge amount of metadata. The final flaw is that the requirements of multi-user concurrent accessing based on massive data are not effectively satisfied on the internet. A novel approach, Hierarchical Optimization Model (HOM), is presented to solve the incapability of GeoNetwork working with massive data in this paper. HOM optimizes the GeoNetwork from these aspects: internal procedure, external deployment strategies, etc. This model builds an efficient index for accessing huge metadata and supporting concurrent processes. In this way, the services based on GeoNetwork can maintain stable while running massive metadata. As an experiment, we deployed more than 30 GeoNetwork nodes, and harvest nearly 1.1 million metadata. From the contrast between the HOM-improved software and the original one, the model makes indexing and retrieval processes more quickly and keeps the speed stable on metadata amount increasing. It also shows stable on multi-user concurrent accessing to system services, the experiment achieved good results and proved that our optimization model is efficient and reliable.

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

    ERIC Educational Resources Information Center

    Huang, Chiungjung

    2011-01-01

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

  12. Supply-Chain Optimization Template

    NASA Technical Reports Server (NTRS)

    Quiett, William F.; Sealing, Scott L.

    2009-01-01

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

  13. RF Gun Optimization Study

    SciTech Connect

    Alicia Hofler; Pavel Evtushenko

    2007-07-03

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. A genetic algorithm (GA) has been successfully used to optimize DC photo injector designs at Cornell University [1] and Jefferson Lab [2]. We propose to apply GA techniques to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize a system that has been benchmarked with beam measurements and simulation.

  14. Autoimmune control of lesion growth in CNS with minimal damage

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    Lesions in central nervous system (CNS) and their growth leads to debilitating diseases like Multiple Sclerosis (MS), Alzheimer's etc. We developed a model earlier [1, 2] which shows how the lesion growth can be arrested through a beneficial auto-immune mechanism. We compared some of the dynamical patterns in the model with different facets of MS. The success of the approach depends on a set of control parameters and their phase space was shown to have a smooth manifold separating the uncontrolled lesion growth region from the controlled. Here we show that an optimal set of parameter values exist in the model which minimizes system damage while, at once, achieving control of lesion growth.

  15. Environmental optimal control strategies based on plant canopy photosynthesis responses and greenhouse climate model

    NASA Astrophysics Data System (ADS)

    Deng, Lujuan; Xie, Songhe; Cui, Jiantao; Liu, Tao

    2006-11-01

    It is the essential goal of intelligent greenhouse environment optimal control to enhance income of cropper and energy save. There were some characteristics such as uncertainty, imprecision, nonlinear, strong coupling, bigger inertia and different time scale in greenhouse environment control system. So greenhouse environment optimal control was not easy and especially model-based optimal control method was more difficult. So the optimal control problem of plant environment in intelligent greenhouse was researched. Hierarchical greenhouse environment control system was constructed. In the first level data measuring was carried out and executive machine was controlled. Optimal setting points of climate controlled variable in greenhouse was calculated and chosen in the second level. Market analysis and planning were completed in third level. The problem of the optimal setting point was discussed in this paper. Firstly the model of plant canopy photosynthesis responses and the model of greenhouse climate model were constructed. Afterwards according to experience of the planting expert, in daytime the optimal goals were decided according to the most maximal photosynthesis rate principle. In nighttime on plant better growth conditions the optimal goals were decided by energy saving principle. Whereafter environment optimal control setting points were computed by GA. Compared the optimal result and recording data in real system, the method is reasonable and can achieve energy saving and the maximal photosynthesis rate in intelligent greenhouse

  16. Achieving empowerment through information.

    PubMed

    Parmalee, J C; Scholomiti, T O; Whitman, P; Sees, M; Smith, D; Gardner, E; Bastian, C

    1993-05-01

    Despite the problems we encountered, which are not uncommon with the development and implementation of any data system, we are confident that our success in achieving our goals is due to the following: establishing a reliable information database connecting several related departments; interfacing with registration and billing systems to avoid duplication of data and chance for error; appointing a qualified Systems Manager devoted to the project; developing superusers to include intensive training in the operating system (UNIX), parameters of the information system, and the report writer. We achieved what we set out to accomplish: the development of a reliable database and reports on which to base a variety of hospital decisions; improved hospital utilization; reliable clinical data for reimbursement, quality management, and credentialing; enhanced communication and collaboration among departments; and an increased profile of the departments and staff. Data quality specialists, Utilization Management and Quality Management coordinators, and the Medical Staff Credentialing Supervisor and their managers are relied upon by physicians and administrators to provide timely information. The staff are recognized for their knowledge and expertise in their department-specific information. The most significant reward is the potential for innovation. Users are no longer restricted to narrow information corridors. UNIX programming encourages creativity without demanding a degree in computer science. The capability to reach and use diverse hospital database information is no longer a dream. PMID:10139109

  17. Parametric Design Optimization By Integrating CAD Systems And Optimization Tools

    NASA Astrophysics Data System (ADS)

    Rehan, M.; Olabi, A. G.

    2009-11-01

    Designing a cost effective product in minimum time is a complex process. In order to achieve this goal the requirement of optimum designs are becoming more important. One of the time consuming factor in the design optimization cycle is the modifications of Computer Aided Design (CAD) model after optimization. In conventional design optimization techniques the design engineer has to update the CAD model after receiving optimum design from optimization tools. It is worthwhile using parametric design optimization process to minimize the optimization cycle time. This paper presents a comprehensive study to integrate the optimization parameters between CAD system and optimization tools which were driven from a single user environment. Finally, design optimization of a Compressed Natural Gas (CNG) cylinder was implemented as case study. In this case study the optimization tools were fully integrated with CAD system, therefore, all the deliverables including; part design, drawings and assembly can be automatically updated after achieving the optimum geometry having minimum volume and satisfying all imposed constraints.

  18. Bilingualism and academic achievement.

    PubMed

    Han, Wen-Jui

    2012-01-01

    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 kindergarten, Mixed Bilingual children fully closed the math gap with their White English Monolingual peers by fifth grade. However, because non-English-Dominant Bilinguals and non-English Monolinguals started kindergarten with significantly lower reading and math scores compared to their English Monolingual peers, by fifth grade the former groups still had significantly lower scores. School-level factors explained about one third of the reductions in the differences in children's academic performance. PMID:22098584

  19. MPQC: Performance Analysis and Optimization

    SciTech Connect

    Sarje, Abhinav; Williams, Samuel; Bailey, David

    2012-11-30

    MPQC (Massively Parallel Quantum Chemistry) is a widely used computational quantum chemistry code. It is capable of performing a number of computations commonly occurring in quantum chemistry. In order to achieve better performance of MPQC, in this report we present a detailed performance analysis of this code. We then perform loop and memory access optimizations, and measure performance improvements by comparing the performance of the optimized code with that of the original MPQC code. We observe that the optimized MPQC code achieves a significant improvement in the performance through a better utilization of vector processing and memory hierarchies.

  20. Achieving closure at Fernald

    SciTech Connect

    Bradburne, John; Patton, Tisha C.

    2001-02-25

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