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Sample records for achieving optimal growth

  1. 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

  2. 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…

  3. 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…

  4. Mathematics Coursework Regulates Growth in Mathematics Achievement

    ERIC Educational Resources Information Center

    Ma, Xin; Wilkins, Jesse L. M.

    2007-01-01

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

  5. 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…

  6. Optimal growth trajectories with finite carrying capacity.

    PubMed

    Caravelli, F; Sindoni, L; Caccioli, F; Ududec, C

    2016-08-01

    We consider the problem of finding optimal strategies that maximize the average growth rate of multiplicative stochastic processes. For a geometric Brownian motion, the problem is solved through the so-called Kelly criterion, according to which the optimal growth rate is achieved by investing a constant given fraction of resources at any step of the dynamics. We generalize these finding to the case of dynamical equations with finite carrying capacity, which can find applications in biology, mathematical ecology, and finance. We formulate the problem in terms of a stochastic process with multiplicative noise and a nonlinear drift term that is determined by the specific functional form of carrying capacity. We solve the stochastic equation for two classes of carrying capacity functions (power laws and logarithmic), and in both cases we compute the optimal trajectories of the control parameter. We further test the validity of our analytical results using numerical simulations. PMID:27627325

  7. The Effects of Academic Optimism on Elementary Reading Achievement

    ERIC Educational Resources Information Center

    Bevel, Raymona K.; Mitchell, Roxanne M.

    2012-01-01

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

  8. Reading Achievement Growth in Children with Language Impairments

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  9. 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.

  10. Academic Optimism and Student Achievement in Urban Elementary Schools

    ERIC Educational Resources Information Center

    Smith, Page A.; Hoy, Wayne K.

    2007-01-01

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

  11. A Domain-level Approach to Describing Growth in Achievement

    ERIC Educational Resources Information Center

    Schulz, E. Matthew; Lee, Won-Chan; Mullen, Ken

    2005-01-01

    Descriptions of growth in educational achievement often rely on the notion that higher-level students can do whatever lower-level students can do, plus at least one more thing. This article presents a method of supporting such descriptions using the data of a subject-area achievement test. Multiple content domains with an expected order of…

  12. 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…

  13. 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.

  14. Growth mindset tempers the effects of poverty on academic achievement.

    PubMed

    Claro, Susana; Paunesku, David; Dweck, Carol S

    2016-08-01

    Two largely separate bodies of empirical research have shown that academic achievement is influenced by structural factors, such as socioeconomic background, and psychological factors, such as students' beliefs about their abilities. In this research, we use a nationwide sample of high school students from Chile to investigate how these factors interact on a systemic level. Confirming prior research, we find that family income is a strong predictor of achievement. Extending prior research, we find that a growth mindset (the belief that intelligence is not fixed and can be developed) is a comparably strong predictor of achievement and that it exhibits a positive relationship with achievement across all of the socioeconomic strata in the country. Furthermore, we find that students from lower-income families were less likely to hold a growth mindset than their wealthier peers, but those who did hold a growth mindset were appreciably buffered against the deleterious effects of poverty on achievement: students in the lowest 10th percentile of family income who exhibited a growth mindset showed academic performance as high as that of fixed mindset students from the 80th income percentile. These results suggest that students' mindsets may temper or exacerbate the effects of economic disadvantage on a systemic level. PMID:27432947

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

    ERIC Educational Resources Information Center

    Johnson, Ursula Yvette

    2011-01-01

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

  16. Growth in Mathematics Achievement: Analysis with Classification and Regression Trees

    ERIC Educational Resources Information Center

    Ma, Xin

    2005-01-01

    A recently developed statistical technique, often referred to as classification and regression trees (CART), holds great potential for researchers to discover how student-level (and school-level) characteristics interactively affect growth in mathematics achievement. CART is a host of advanced statistical methods that statistically cluster…

  17. 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…

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

    PubMed

    Seals, Douglas R; Melov, Simon

    2014-09-01

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

  19. 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

  20. 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

  1. Optimized Delivery System Achieves Enhanced Endomyocardial Stem Cell Retention

    PubMed Central

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

    2014-01-01

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

  2. Toward achieving optimal response: understanding and managing antidepressant side effects

    PubMed Central

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

    2008-01-01

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

  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

  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. 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…

  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. 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.

  8. Optimizing the Growth of (111) Diamond for Diamond Based Magnetometry

    NASA Astrophysics Data System (ADS)

    Kamp, Eric; Godwin, Patrick; Samarth, Nitin; Snyder, David; de Las Casas, Charles; Awschalom, David D.

    Magnetometers based on nitrogen vacancy (NV) ensembles have recently achieved sub-picotesla sensitivities [Phys. Rev. X 5, 041001(2015)], putting the technique on par with SQUID and MFM magnetometry.Typically these sensors use (100) oriented diamond with NV centers forming along all four (111) crystal orientations.This allows for vector magnetometry, but is a hindrance to the absolute sensitivity. Diamond grown on (111) oriented substrates through microwave plasma enhanced chemical vapor deposition(MP-CVD) provides a promising route in this context since such films can exhibit preferential orientation greater than 99% [Appl. Phys. Lett.104, 102407 (2014)]. An important challenge though is to achieve sufficiently high NV center densities required for enhancing the sensitivity of an NV ensemble magnetometer.We report systematic studies of the MP-CVD growth and characterization of (111) oriented diamond, where we vary growth temperature, methane concentration, and nitrogen doping. For each film we study the Nitrogen to NV ratio, the NV- to NV0 ratio, and alignment percentage to minimize sources of decoherence and ensure preferential alignment. From these measurements we determine the optimal growth parameters for high sensitivity, NV center ensemble scalar magnetometry. Funded by NSF-DMR.

  9. 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.

  10. Multidisciplinary optimization for engineering systems: Achievements and potential

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw

    1989-01-01

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

  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. 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.

  13. 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

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

    DOEpatents

    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. 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…

  16. Multiphase Nano-Composite Coatings for Achieving Energy Optimization

    SciTech Connect

    Nainaparampil, Jose

    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. 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…

  18. 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…

  19. 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

  20. 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…

  1. 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

  2. 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...

  3. 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.

  4. 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…

  5. 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…

  6. 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…

  7. 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.…

  8. 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…

  9. 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…

  10. 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.

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

    PubMed

    Ruini, Chiara; Fava, Giovanni A

    2012-01-01

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

  13. Achieving optimal aesthetics for direct and indirect restorations with microhybrid composite resins.

    PubMed

    Okuda, Wynn H

    2005-04-01

    In aesthetic dentistry, material science has played a key role in the development of natural-appearing restorations. Despite the progress, there have been challenges in achieving a harmonious integration of direct and indirect posterior restorations. Although porcelain restorations provide natural aesthetics, ceramics cannot be applied via direct techniques. Consequently, composite resins are valuable alternatives for conservative posterior restorations. In addition, because of their differing physical and optical properties, optimal aesthetic blending with porcelain and resin cannot be routinely achieved. This article explores the potential of composite resins as a direct and indirect restorative option in achieving the most favorable natural blend in the posterior region. PMID:15974036

  14. 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…

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

    ERIC Educational Resources Information Center

    Johnson, Ursula Y.; Hull, Darrell M.

    2014-01-01

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

  16. 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

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

    ERIC Educational Resources Information Center

    Geary, David C.

    2011-01-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  19. 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…

  20. 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…

  1. 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

  2. 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.

  3. 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

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

    PubMed

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

    2014-01-01

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

  5. 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

  6. 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.

  7. Numerical Optimization of the Thermal Field in Bridgman Detached Growth

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  8. Robust, integrated computational control of NMR experiments to achieve optimal assignment by ADAPT-NMR.

    PubMed

    Bahrami, Arash; Tonelli, Marco; Sahu, Sarata C; Singarapu, Kiran K; Eghbalnia, Hamid R; Markley, John L

    2012-01-01

    ADAPT-NMR (Assignment-directed Data collection Algorithm utilizing a Probabilistic Toolkit in NMR) represents a groundbreaking prototype for automated protein structure determination by nuclear magnetic resonance (NMR) spectroscopy. With a [(13)C,(15)N]-labeled protein sample loaded into the NMR spectrometer, ADAPT-NMR delivers complete backbone resonance assignments and secondary structure in an optimal fashion without human intervention. ADAPT-NMR achieves this by implementing a strategy in which the goal of optimal assignment in each step determines the subsequent step by analyzing the current sum of available data. ADAPT-NMR is the first iterative and fully automated approach designed specifically for the optimal assignment of proteins with fast data collection as a byproduct of this goal. ADAPT-NMR evaluates the current spectral information, and uses a goal-directed objective function to select the optimal next data collection step(s) and then directs the NMR spectrometer to collect the selected data set. ADAPT-NMR extracts peak positions from the newly collected data and uses this information in updating the analysis resonance assignments and secondary structure. The goal-directed objective function then defines the next data collection step. The procedure continues until the collected data support comprehensive peak identification, resonance assignments at the desired level of completeness, and protein secondary structure. We present test cases in which ADAPT-NMR achieved results in two days or less that would have taken two months or more by manual approaches. PMID:22427982

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

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

  10. 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.

  11. 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…

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

    SciTech Connect

    Kudchadker, Rajat J.; Pugh, Thomas J.; Swanson, David A.; Bruno, Teresa L.; Bolukbasi, Yasemin; Frank, Steven J.

    2012-01-01

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

  13. 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

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

    ERIC Educational Resources Information Center

    Henry, Kimberly L.

    2010-01-01

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

  15. Student Course Taking and Teacher Quality: Their Effects on Achievement and Growth

    ERIC Educational Resources Information Center

    Heck, Ronald H.; Mahoe, Rochelle

    2010-01-01

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

  16. 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,…

  17. 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

  18. 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…

  19. Growth, Optical Properties, and Optimization of Infrared Optoelectronic Materials

    NASA Astrophysics Data System (ADS)

    Webster, Preston Thomas

    High-performance III-V semiconductors based on ternary alloys and superlattice systems are fabricated, studied, and compared for infrared optoelectronic applications. InAsBi is a ternary alloy near the GaSb lattice constant that is not as thoroughly investigated as other III-V alloys and that is challenging to produce as Bi has a tendency to surface segregate and form droplets during growth rather than incorporate. A growth window is identified within which high-quality droplet-free bulk InAsBi is produced and Bi mole fractions up to 6.4% are obtained. Photoluminescence with high internal quantum efficiency is observed from InAs/InAsBi quantum wells. The high structural and optical quality of the InAsBi materials examined demonstrates that bulk, quantum well, and superlattice structures utilizing InAsBi are an important design option for efficient infrared coverage. Another important infrared material system is InAsSb and the strain-balanced InAs/InAsSb superlattice on GaSb. Detailed examination of X-ray diffraction, photoluminescence, and spectroscopic ellipsometry data provides the temperature and composition dependent bandgap of bulk InAsSb. The unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattice is measured and found to significantly impact the analysis of the InAs/InAsSb band alignment. In the analysis of the absorption spectra, the ground state absorption coefficient and transition strength of the superlattice are proportional to the square of the electron-hole wavefunction overlap; wavefunction overlap is therefore a major design parameter in terms of optimizing absorption in these materials. Furthermore in addition to improvements through design optimization, the optical quality of the materials studied is found to be positively enhanced with the use of Bi as a surfactant during molecular beam epitaxy growth. A software tool is developed that calculates and optimizes the miniband structure of semiconductor

  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. 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.

  2. Achieving optimal gingival esthetics around restored natural teeth and implants. Rationale, concepts, and techniques.

    PubMed

    Bichacho, N

    1998-10-01

    The role of prosthetic restorations in the final appearance of the surrounding soft tissues has long been recognized. Innovative prosthodontic concepts as described should be used to enhance the biologic as well as the esthetic data of the supporting tissues, in natural teeth and implants alike. Combined dental treatment modalities of different kinds (i.e., orthodontics, periodontal treatment) are often required for optimal results. Meticulous care and attention to the delicate soft tissues should be given throughout all phases of the treatment, with a view to achieving a functional, healthy, and esthetic oral environment. PMID:9891656

  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. 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

  5. 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.

  6. 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.

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

    PubMed

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

    2009-07-01

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

  8. Analysis of green algal growth via dynamic model simulation and process optimization.

    PubMed

    Zhang, Dongda; Chanona, Ehecatl Antonio Del-Rio; Vassiliadis, Vassilios S; Tamburic, Bojan

    2015-10-01

    Chlamydomonas reinhardtii is a green microalga with the potential to generate sustainable biofuels for the future. Process simulation models are required to predict the impact of laboratory-scale growth experiments on future scaled-up system operation. Two dynamic models were constructed to simulate C. reinhardtii photo-autotrophic and photo-mixotrophic growth. A novel parameter estimation methodology was applied to determine the values of key parameters in both models, which were then verified using experimental results. The photo-mixotrophic model was used to accurately predict C. reinhardtii growth under different light intensities and in different photobioreactor configurations. The optimal dissolved CO2 concentration for C. reinhardtii photo-autotrophic growth was determined to be 0.0643 g·L(-1) , and the optimal light intensity for algal growth was 47 W·m(-2) . Sensitivity analysis revealed that the primary factor limiting C. reinhardtii growth was its intrinsic cell decay rate rather than light attenuation, regardless of the growth mode. The photo-mixotrophic growth model was also applied to predict the maximum biomass concentration at different flat-plate photobioreactors scales. A double-exposure-surface photobioreactor with a lower light intensity (less than 50 W·m(-2) ) was the best configuration for scaled-up C. reinhardtii cultivation. Three different short-term (30-day) C. reinhardtii photo-mixotrophic cultivation processes were simulated and optimised. The maximum biomass productivity was 0.053 g·L(-1) ·hr(-1) , achieved under continuous photobioreactor operation. The continuous stirred-tank reactor was the best operating mode, as it provides both the highest biomass productivity and lowest electricity cost of pump operation. PMID:25855209

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

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

    PubMed

    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 achieved "optimal outcomes" (OOs). Since residual impairments in these individuals might be expected in deficits central to autism, and in developmentally advanced skills, EF was examined in 34 individuals who achieved OOs, 43 individuals with high-functioning autism (HFA), and 34 typically developing (TD) peers. Groups were matched on age (M = 13.49), gender, and nonverbal IQ (NVIQ) but differed on verbal IQ (VIQ; HFA < TD, OO). On direct assessment, all three groups demonstrated average EF; however, the OO and HFA groups exhibited more impulsivity and less efficient planning and problem-solving than the TD group, and more HFA participants exhibited below average inhibition than did OO and TD participants. Parent-report measures revealed average EF among the OO and TD groups; however, the OO group exhibited more difficulty than the TD group on set-shifting and working memory. HFA participants demonstrated more difficulty on all parent-reported EF domains, with a clinical impairment in attention-shifting. Results suggest that EF in OO appears to be within the average range, even for functions that were impaired among individuals with HFA. Despite their average performance, however, the OO and TD groups differed on measures of impulsivity, set-shifting, problem-solving, working memory, and planning, suggesting that the OO group does not have the above-average EF scores of the TD group despite their high-average IQs. PMID:23731181

  16. 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

  17. Assessment of the Optimal Stimulus Pattern to Achieve Rapid Dorsal Hippocampal Kindling in Rats

    PubMed Central

    Etemadi, Fatemeh; Sayyah, Mohammad; Gholami Pourbadie, Hamid; Babapour, Vahab

    2015-01-01

    Introduction: Although hippocampus is the most famous brain area involved in temporal lobe epilepsy, hippocampal kindling (HK) develops very slowly. Hence, rapid kindling is usually preferred to the traditional kindling and it is widely used. In this article we aimed at finding the optimal stimulus pattern, which yields the fastest HK rate. Methods: Stimulus patterns with different duration (2, 3, 5 and 10 s) and inter-train interval (ITI) (5, 10 and 30 min) as well as number of trains in 24 h (8 and 12) were exerted to rats’ dorsal hippocampus. The stimuli were continued until appearance of 3 consecutive generalized seizures or maximum 7 days stimulations. Results: While the protocol with train duration of 10 s and ITI of 30 min caused the fastest kindling rate and the most growth of afterdischarges, the protocol with train duration of 5 s and ITI of 5 min was the most time-consuming protocol among protocols tested. Discussion: Rapid HK develops with a time course of days compared to weeks in traditional kindling. Train duration and inter-train interval are key factors for rapid HK. Among the patterns, 12 trains/24h of 50Hz monophasic square wave with 10 s duration and 30 min interval between trains, is the best stimulus pattern for eliciting rapid dorsal HK. PMID:27307955

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

    PubMed

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

    2014-04-01

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

  19. 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

  20. 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

  1. Hierarchically structured hematite architectures achieved by growth in a silica hydrogel.

    PubMed

    Asenath-Smith, Emily; Hovden, Robert; Kourkoutis, Lena F; Estroff, Lara A

    2015-04-22

    Biomineralization strategies include the use of hydrogels to direct the formation of composite, single-crystal-like structures with unique structure-property profiles. Application of similar synthetic approaches to transition-metal oxides has the promise to yield low-temperature routes to hierarchically structured crystals that are optimized for a range of applications. Here, growth of hematite (α-Fe2O3) within a silica hydrogel resulted in hierarchical, mosaic crystals preferentially expressing catalytically active {110} facets, which are absent in solution-grown controls. Quantitative structural and compositional analysis reveals architectural changes that begin with the incorporation of silicon into the hematite lattice and propagate through to the nanoscale domain structure and assembly, leading to microscale morphologies that show improved photocatalytic performance. This work demonstrates the potential of applying bioinspired crystallization techniques to design functional oxides with multiscale architectural features. PMID:25822466

  2. 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

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  4. Calibration of STUD+ parameters to achieve optimally efficient broadband adiabatic decoupling in a single transient

    PubMed

    Bendall; Skinner

    1998-10-01

    for a single sech/tanh pulse. Residual splitting of the centerband, normally associated with incomplete or inefficient decoupling, is not seen in sech/tanh decoupling and therefore cannot be used as a measure of adiabatic decoupling efficiency. The calibrated experimental performance levels achieved in this study are within 20% of theoretical performance levels derived previously for ideal sech/tanh decoupling at high power, indicating a small scope for further improvement at practical RF power levels. The optimization procedures employed here will be generally applicable to any good combination of adiabatic inversion pulse and phase cycle. Copyright 1998 Academic Press. PMID:9761708

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  6. 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.

  7. Academic achievement and psychological adjustment in short children. The National Cooperative Growth Study.

    PubMed

    Stabler, B; Clopper, R R; Siegel, P T; Stoppani, C; Compton, P G; Underwood, L E

    1994-02-01

    Limited information is available on the educational and behavioral functioning of short children. Through 27 participating medical centers, we administered a battery of psychologic tests to 166 children referred for growth hormone (GH) treatment (5 to 16 years) who were below the third percentile for height (mean height = -2.7 SD). The sample consisted of 86 children with isolated growth-hormone deficiency (GHD) and 80 children with idiopathic short stature (ISS). Despite average intelligence, absence of significant family dysfunction, and advantaged social background, a large number of children had academic underachievement. Both groups showed significant discrepancy (p < .01) between IQ and achievement scores in reading (6%), spelling (10%), and arithmetic (13%) and a higher-than-expected rate of behavior problems (GHD, 12%, p < .0001; ISS, 10%, p < .0001). Behavior problems included elevated rates of internalizing behavior (e.g., anxiety, somatic complaints) and externalizing behavior (e.g., impulsive, distractable, attention-seeking). Social competence was reduced in school-related activities for GHD patients (6%, p < .03). The high frequency of underachievement, behavior problems, and reduced social competency in these children suggests that short stature itself may predispose them to some of their difficulties. Alternately, parents of short, underachieving children may be more likely to seek help. In addition, some problems may be caused by factors related to specific diagnoses. PMID:8195431

  8. Tripartite Growth Trajectories of Reading and Math Achievement: Tracking National Academic Progress at Primary, Middle, and High School Levels

    ERIC Educational Resources Information Center

    Lee, Jaekyung

    2010-01-01

    This study examines trends in American students' growth trajectories in reading and math achievement over the past three decades. Drawing upon multiple sources of national assessment data, cohort analyses provide new evidence on the stability and change of national academic growth curves. The emerging trends imply a tripartite pattern where…

  9. Gender Differences in Growth in Mathematics Achievement: Three-Level Longitudinal and Multilevel Analyses of Individual, Home, and School Influences.

    ERIC Educational Resources Information Center

    Ai, Xiaoxia

    2002-01-01

    Focuses on gender differences in growth in mathematics achievement in relation to various social-psychological factors such as attitude towards mathematics, self-esteem, parents' academic encouragement, mathematics teachers' expectations, and peer influence. Results indicate that gender differences in growth in mathematics varied by the student's…

  10. 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…

  11. 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…

  12. 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…

  13. 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

  14. 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

  15. 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…

  16. Extrauterine growth restriction in preterm infants: importance of optimizing nutrition in neonatal intensive care units.

    PubMed

    Yu, Victor Y H

    2005-10-01

    Extrauterine growth restriction in preterm infants secondary to suboptimal nutrition is a major problem in neonatal intensive care units. Evidence is emerging that early growth deficits have long-term adverse effects, including short stature and poor neurodevelopmental outcomes. The parenteral route of feeding is essential to maintain nutritional integrity before successful transition to the enteral route of feeding is achieved. Nevertheless, early initiation of enteral feeding in sub-nutritional trophic quantity is vital for promoting gut motility and bile secretion, inducing lactase activity, and reducing sepsis and cholestatic jaundice. Results emerging from over sixty randomized clinical trials are available for providing a template on which feeding protocols can be based. Preterm breast milk expressed from the infant's own mother is the milk of choice. Supplementation with a human milk fortifier is necessary to optimize nutritional intake. Preterm formulas are an appropriate substitute for preterm human milk when the latter is unavailable. There are over ten systematic reviews of randomized controlled trials published by the Cochrane Library that addressed feeding strategies, but most do not address long-term outcome measures of clinical importance. There is an urgent need for large-scale, long-term randomized controlled trials to help evaluate metabolic, growth, and neurodevelopmental responses of preterm infants to earlier and more aggressive nutritional management. PMID:16158465

  17. Achieving Finite Element Mesh Quality via Optimization of the Jacobian Matrix Norm and Associated Quantities, Part 1 - A Framework for Surface Mesh Optimization

    SciTech Connect

    Knupp, P.M.

    1999-01-18

    Structured mesh quality optimization methods are extended to optimization of unstructured triangular, quadrilateral, and mixed finite element meshes. N"ew interpretations of well-known nodally-bssed objective functions are made possible using matrices and matrix norms. The matrix perspective also suggests several new objective functions. Particularly significant is the interpretation of the Oddy metric and the Smoothness objective functions in terms of the condition number of the metric tensor and Jacobian matrix, respectively. Objective functions are grouped according to dimensionality to form weighted combinations. A simple unconstrained local optimum is computed using a modiiied N-ewton iteration. The optimization approach was implemented in the CUBIT mesh generation code and tested on several problems. Results were compared against several standard element-based quaIity measures to demonstrate that good mesh quality can be achieved with nodally-based objective functions.

  18. 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. PMID:25891207

  19. Tumor Growth Prediction with Hyperelastic Biomechanical Model, Physiological Data Fusion, and Nonlinear Optimization

    PubMed Central

    Wong, Ken C. L.; Summers, Ronald M.; Kebebew, Electron; Yao, Jianhua

    2015-01-01

    Tumor growth prediction is usually achieved by physiological modeling and model personalization from clinical measurements. Although image-based frameworks have been proposed with promising results, different issues such as infinitesimal strain assumption, complicated optimization procedures, and lack of functional information, may limit the prediction performance. Therefore, we propose a framework which comprises a hyperelastic biomechanical model for better physiological plausibility, gradient-free nonlinear optimization for more flexible choices of models and objective functions, and physiological data fusion of structural and functional images for better subject-specificity. Experiments were performed on synthetic and clinical data to verify parameter estimation capability and prediction performance of the framework. Comparisons of using different biomechanical models and objective functions were also performed. From the experimental results on eight patient data sets, the recall, precision, and relative volume difference (RVD) between predicted and measured tumor volumes are 84.85±6.15%, 87.08±7.83%, and 13.81±6.64% respectively. PMID:25485359

  20. Proportion of corn silage in diets of feedlot steers fed to achieve stepwise increases in growth.

    PubMed

    Rossi, J E; Loerch, S C

    2001-06-01

    Two experiments were conducted to investigate the effects of proportion of dietary corn silage during periods of feed restriction on performance of steers. In Exp. 1, Simmental x Angus steer calves (n = 107; initial BW = 273 +/- 3.8 kg) were allotted to 12 pens with eight or nine steers/pen and four pens/treatment. Periods of growth were 273 to 366 kg BW (Period 1), 367 to 501 kg BW (Period 2), and 502 to 564 kg BW (Period 3). In two of the dietary regimens, steers were given ad libitum access to feed throughout the experiment and were fed either a 15% corn silage diet in each period or an 85, 50, and 15% corn silage diet in Periods 1, 2, and 3; respectively. In the third feeding regimen, a programmed intake feeding regimen was used. Steers were fed a 15% corn silage diet in each period. However, feed intake was restricted to achieve a predicted gain of 1.13 kg/d in Period 1 and 1.36 kg/d in Period 2, and feed was offered for ad libitum consumption in Period 3. For the entire experiment, ADG was similar (P = 0.41) among treatments and feed efficiency was lower (P < 0.10) for steers in the corn silage regimen than for steers in the programmed intake and ad libitum regimens. In Exp. 2, Simmental x Angus steer calves (n = 106; initial BW = 233 +/- 2 kg) were allotted by BW to 12 pens (three pens/treatment) and fed in three periods similar to those described in Exp. 1. Four feeding regimens were investigated: 1) AL; steers were offered a 15% corn silage diet for ad libitum consumption in all three periods; 2) PI; DMI was programmed to achieve gains as described in Exp. 1; 3) CS-HLL; programmed intake as described above except diets contained 85, 15, and 15% corn silage in Periods 1, 2, and 3, respectively; and 4) CS-HIL; same feeding regimens as CS-HLL, except diets contained 85, 50, and 15% corn silage in Periods 1, 2, and 3, respectively. Steers were given ad libitum access to feed in Period 3. Overall ADG was lower (P < 0.05) for steers in the CS-HLL and CS

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

    ERIC Educational Resources Information Center

    Burgess, Melissa L.

    2010-01-01

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

  2. Achieving diverse and monoallelic olfactory receptor selection through dual-objective optimization design.

    PubMed

    Tian, Xiao-Jun; Zhang, Hang; Sannerud, Jens; Xing, Jianhua

    2016-05-24

    Multiple-objective optimization is common in biological systems. In the mammalian olfactory system, each sensory neuron stochastically expresses only one out of up to thousands of olfactory receptor (OR) gene alleles; at the organism level, the types of expressed ORs need to be maximized. Existing models focus only on monoallele activation, and cannot explain recent observations in mutants, especially the reduced global diversity of expressed ORs in G9a/GLP knockouts. In this work we integrated existing information on OR expression, and constructed a comprehensive model that has all its components based on physical interactions. Analyzing the model reveals an evolutionarily optimized three-layer regulation mechanism, which includes zonal segregation, epigenetic barrier crossing coupled to a negative feedback loop that mechanistically differs from previous theoretical proposals, and a previously unidentified enhancer competition step. This model not only recapitulates monoallelic OR expression, but also elucidates how the olfactory system maximizes and maintains the diversity of OR expression, and has multiple predictions validated by existing experimental results. Through making an analogy to a physical system with thermally activated barrier crossing and comparative reverse engineering analyses, the study reveals that the olfactory receptor selection system is optimally designed, and particularly underscores cooperativity and synergy as a general design principle for multiobjective optimization in biology. PMID:27162367

  3. Early Acceleration of Students in Mathematics: Does It Promote Growth and Stability of Growth in Achievement across Mathematical Areas?

    ERIC Educational Resources Information Center

    Ma, Xin

    2005-01-01

    Using data from the Longitudinal Study of American Youth (LSAY), the present study examined whether early acceleration of students into formal algebra at the beginning of middle school promoted evident growth in different mathematical areas (basic skills, algebra, geometry, and quantitative literacy) and stable growth across these mathematical…

  4. Optimization of medium components and physicochemical parameters to simultaneously enhance microbial growth and production of lypolitic enzymes by Stenotrophomonas sp.

    PubMed

    Mazzucotelli, Cintia Anabela; Agüero, María Victoria; Del Rosario Moreira, María; Ansorena, María Roberta

    2016-05-01

    The optimization of lipase and esterase production (LP and EP) and bacterial growth (BG) of a Stenotrophomonas sp. strain was developed. For this purpose, the effect of five different medium components and three physicochemical parameters were evaluated using a Plackett-Burman statistical design. Among eight variables, stirring speed, pH, and peptone concentration were found to be the most effective factors on the three responses under evaluation. An optimization study applying Box-Behnken response surface methodology was used to study the interactive effects of the three selected variables on LP/EP and microorganism growth. Predicted models were found to be significant with high regression coefficients (90%-99%). By using the desirability function approach, the optimum condition applying simultaneous optimization of the three responses under study resulted to be: stirring speed of 100 rpm, pH of 7.5, and a peptone concentration of 10 g/L, with a desirability value of 0.977. Under these optimal conditions, it is possible to achieve in the optimized medium a 15-fold increase in esterase productivity, a 117-fold increase in lipase production, and a 9-log CFU/mL increase in BG, compared with the basal medium without agitation. PMID:25817426

  5. 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.

  6. 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…

  7. 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

  8. Plasticity in the growth of the chick eye: Emmetropization achieved by alternate morphologies

    PubMed Central

    Wahl, Christina; Li, Tong; Howland, Howard

    2015-01-01

    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 11 weeks, we returned chicks to normal (N) conditions with 12 hrs. of light alternating with 12 hrs. of darkness (designated the “R”, or recovery, condition) for total periods of 4, 7, 11, or 17 weeks. 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 one week after 3 weeks CL treatment. In R chicks exposed to CL for 11 weeks 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

  9. 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

  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. Achieving Optimal Self-Adaptivity for Dynamic Tuning of Organic Semiconductors through Resonance Engineering.

    PubMed

    Tao, Ye; Xu, Lijia; Zhang, Zhen; Chen, Runfeng; Li, Huanhuan; Xu, Hui; Zheng, Chao; Huang, Wei

    2016-08-01

    Current static-state explorations of organic semiconductors for optimal material properties and device performance are hindered by limited insights into the dynamically changed molecular states and charge transport and energy transfer processes upon device operation. Here, we propose a simple yet successful strategy, resonance variation-based dynamic adaptation (RVDA), to realize optimized self-adaptive properties in donor-resonance-acceptor molecules by engineering the resonance variation for dynamic tuning of organic semiconductors. Organic light-emitting diodes hosted by these RVDA materials exhibit remarkably high performance, with external quantum efficiencies up to 21.7% and favorable device stability. Our approach, which supports simultaneous realization of dynamically adapted and selectively enhanced properties via resonance engineering, illustrates a feasible design map for the preparation of smart organic semiconductors capable of dynamic structure and property modulations, promoting the studies of organic electronics from static to dynamic. PMID:27403886

  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. Optimal thickness of silicon membranes to achieve maximum thermoelectric efficiency: A first principles study

    NASA Astrophysics Data System (ADS)

    Mangold, Claudia; Neogi, Sanghamitra; Donadio, Davide

    2016-08-01

    Silicon nanostructures with reduced dimensionality, such as nanowires, membranes, and thin films, are promising thermoelectric materials, as they exhibit considerably reduced thermal conductivity. Here, we utilize density functional theory and Boltzmann transport equation to compute the electronic properties of ultra-thin crystalline silicon membranes with thickness between 1 and 12 nm. We predict that an optimal thickness of ˜7 nm maximizes the thermoelectric figure of merit of membranes with native oxide surface layers. Further thinning of the membranes, although attainable in experiments, reduces the electrical conductivity and worsens the thermoelectric efficiency.

  14. 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;…

  15. 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…

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

    ERIC Educational Resources Information Center

    Ma, Lingling; Ma, Xin

    2005-01-01

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

  17. The Relationship of Selected Measures of Proprioception to Physical Growth, Motor Performance, and Academic Achievement in Young Children.

    ERIC Educational Resources Information Center

    Haubenstricker, John L.; Milne, D. Conrad

    This study investigates the relationship of selected measures of proprioception to measures of physical growth, motor performance, and academic achievement in young children. Measures were obtained from 321 boys and girls attending kindergarten and first and second grade. Sample correlation matrices were computed on all variables at each grade…

  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. 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…

  20. 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…

  1. An approach toward optimization of the influential growth determinants of opportunistic yeast isolate Pichia guilliermondii.

    PubMed

    Mukherjee, Suprabhat; Mukherjee, Niladri; Roy, Priya; Saini, Prasanta; Sinha Babu, Santi P

    2016-07-01

    The present study reports statistical optimization of growth conditions of an opportunistic fungal strain Pichia guilliermondii, isolated from the blood of patients suffering from bancroftian filariasis. Seven key determinants, namely, primary inoculums size (%), volume (mL) and pH of media, serum proportion, temperature (°C), incubation time (hr), and agitation speed (rpm) that influence in vitro growth of the pathogen were optimized statistically using response surface methodology (RSM). RSM with seven factors and two-level Box-Behnken design was employed for designing experimental run, prediction of case statistics, suitable exploration of quadratic response surfaces, and constructing a second-order polynomial equation. Analysis of variance (ANOVA) showed that primary inoculums size, volume of culture media, temperature, incubation time, and agitation speed exert most significant influence over fungal growth. The RSM study predicted that optimum fungal growth can be obtained using 10% primary inoculums size in 100 mL culture media with pH 6.0, 6.28% serum, 32.5°C temperature, and 24 hr of incubation, alongside agitation speed at 400 rpm. The desirability of the optimized growth model for P. guilliermondii is 99.123%, which indicated its accuracy and acceptability. Finally, the optimized growth module illustrated in the study could be useful in improving in vitro growth of clinically important P. guilliermondii. PMID:26176798

  2. Growth and change in attention problems, disruptive behavior, and achievement from kindergarten to fifth grade.

    PubMed

    Claessens, Amy; Dowsett, Chantelle

    2014-12-01

    Despite widespread interest in children's adjustment problems, existing research does not provide conclusive evidence regarding the direction of the associations of achievement with classroom attention problems and disruptive behavior over the course of elementary school. Using a nationally representative sample of 16,260 kindergarteners, this study examined the temporal sequence of achievement, classroom attention problems, and disruptive behavior, focusing on how changes in skills and problems unfold across key periods between kindergarten and fifth grade. Results indicate that improvements in attention during the earliest years of schooling predict achievement gains through third grade. However, changes in disruptive behavior do not predict subsequent changes in achievement. Evidence linking changes in achievement to changes in classroom attention problems and disruptive behavior was less consistent. These findings point to the need to develop and examine early interventions that can improve attention skills as a mechanism for improving children's academic trajectories in elementary school. PMID:25376191

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. Identification and Treatment of Pathophysiological Comorbidities of Autism Spectrum Disorder to Achieve Optimal Outcomes.

    PubMed

    Frye, Richard E; Rossignol, Daniel A

    2016-01-01

    the optimal treatments for these abnormalities. PMID:27330338

  9. Identification and Treatment of Pathophysiological Comorbidities of Autism Spectrum Disorder to Achieve Optimal Outcomes

    PubMed Central

    Frye, Richard E.; Rossignol, Daniel A.

    2016-01-01

    the optimal treatments for these abnormalities. PMID:27330338

  10. Endonasal endoscopic dacryocystorhinostomy: how to achieve optimal results with simple punch technique.

    PubMed

    Naraghi, Mohsen; Tabatabaii Mohammadi, Sayed Ziaeddin; Sontou, Alain Fabrice; Farajzadeh Deroee, Armin; Boroojerdi, Masoud

    2012-05-01

    Endonasal endoscopic dacryocystorhinostomy (EEDCR) has been popularized as a minimally invasive technique. Although preliminary reports revealed less success in comparison with external approaches, recent endonasal endoscopic surgeries on various types of DCR have preserved advantages of this technique while diminishing the failures. We described our experience on EEDCR, including the main advantages and disadvantages of it. Hundred consecutive cases of lachrymal problems underwent EEDCR utilizing simple punch removal of bone, instead of powered instrumentation or lasers. The medial aspect of the sac was removed in all of patients, while preserving normal mucosa around the sac. Hundred cases of EEDCR were performed on 81 patients, with 19 bilateral procedures. Nine procedures were performed under local anesthesia. Based on a mean 14 months follow-up, 95 cases were free of symptoms, revealing 95% success rate. The punch technique diminishes the expenses of powered or laser instrumentation with comparable results. It seems that preserving normal tissues and creating a patent rhinostomy with least surgical trauma and less subsequent scar, plays the most important role in achieving desirable results. PMID:22065173

  11. A General Multivariate Latent Growth Model with Applications to Student Achievement

    ERIC Educational Resources Information Center

    Bianconcini, Silvia; Cagnone, Silvia

    2012-01-01

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

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. 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...

  17. Effectiveness of increasing the frequency of posaconazole syrup administration to achieve optimal plasma concentrations in patients with haematological malignancy.

    PubMed

    Park, Wan Beom; Cho, Joo-Youn; Park, Sang-In; Kim, Eun Jung; Yoon, Seonghae; Yoon, Seo Hyun; Lee, Jeong-Ok; Koh, Youngil; Song, Kyoung-Ho; Choe, Pyoeng Gyun; Yu, Kyung-Sang; Kim, Eu Suk; Bang, Su Mi; Kim, Nam Joong; Kim, Inho; Oh, Myoung-Don; Kim, Hong Bin; Song, Sang Hoon

    2016-07-01

    Few data are available on whether adjusting the dose of posaconazole syrup is effective in patients receiving anti-cancer chemotherapy. The aim of this prospective study was to analyse the impact of increasing the frequency of posaconazole administration on optimal plasma concentrations in adult patients with haematological malignancy. A total of 133 adult patients receiving chemotherapy for acute myeloid leukaemia or myelodysplastic syndrome who received posaconazole syrup 200 mg three times daily for fungal prophylaxis were enrolled in this study. Drug trough levels were measured by liquid chromatography-tandem mass spectrometry. In 20.2% of patients (23/114) the steady-state concentration of posaconazole was suboptimal (<500 ng/mL) on Day 8. In these patients, the frequency of posaconazole administration was increased to 200 mg four times daily. On Day 15, the median posaconazole concentration was significantly increased from 368 ng/mL [interquartile range (IQR), 247-403 ng/mL] to 548 ng/mL (IQR, 424-887 ng/mL) (P = 0.0003). The median increase in posaconazole concentration was 251 ng/mL (IQR, 93-517 ng/mL). Among the patients with initially suboptimal levels, 79% achieved the optimal level unless the steady-state level was <200 ng/mL. This study shows that increasing the administration frequency of posaconazole syrup is effective for achieving optimal levels in patients with haematological malignancy undergoing chemotherapy. PMID:27234674

  18. 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…

  19. 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…

  20. 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…

  1. 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…

  2. 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

  3. 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

  4. Comparing immune-tumor growth models with drug therapy using optimal control

    NASA Astrophysics Data System (ADS)

    Martins, Marisa C.; Rocha, Ana Maria A. C.; Costa, M. Fernanda P.; Fernandes, Edite M. G. P.

    2016-06-01

    In this paper we compare the dynamics of three tumor growth models that include an immune system and a drug administration therapy using optimal control. The objective is to minimize a combined function of the total of tumor cells over time and a chemotherapeutic drug administration.

  5. 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

  6. 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

  7. Simulation optimization of the cathode deposit growth in a coaxial electrolyzer-refiner

    NASA Astrophysics Data System (ADS)

    Smirnov, G. B.; Fokin, A. A.; Markina, S. E.; Vakhitov, A. I.

    2015-08-01

    The results of simulation of the cathode deposit growth in a coaxial electrolyzer-refiner are presented. The sizes of the initial cathode matrix are optimized. The data obtained by simulation and full-scale tests of the precipitation of platinum from a salt melt are compared.

  8. 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...

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

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

    PubMed

    Ketseoglou, Irene; Bouwer, Gustav

    2013-08-10

    An Anabaena strain (PCC 7120#11) that was genetically engineered to express Bacillus thuringiensis subsp. israelensis cry genes has shown good larvicidal activity against Anopheles arabiensis, a major vector of malaria in Africa. Response surface methodology was used to evaluate the relationship between key growth factors and the volumetric productivity of PCC 7120#11 in an indoor, flat-plate photobioreactor. The interaction of input CO₂ concentration and airflow rate had a statistically significant effect on the volumetric productivity of PCC 7120#11, as did the interaction of airflow rate and photosynthetic photon flux density. Model-based numerical optimization indicated that the optimal factor level combination for maximizing PCC 7120#11 volumetric productivity was a photosynthetic photon flux density of 154 μmol m⁻² s⁻¹ and air enriched with 3.18% (v/v) CO₂ supplied at a flow rate of 1.02 vessel volumes per minute. At the levels evaluated in the study, none of the growth factors had a significant effect on the median lethal concentration of PCC 7120#11 against An. arabiensis larvae. This finding is important because loss of mosquitocidal activity under growth conditions that maximize volumetric productivity would impact on the feasibility of using PCC 7120#11 in malaria vector control programs. The study showed the usefulness of response surface methodology for determination of the optimal growth conditions for a cyanobacterium that is genetically engineered to have larvicidal activity against malaria vectors. PMID:23732832

  15. 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

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

    PubMed

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

    2013-01-01

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

  17. 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.

  18. Optimizing cyanobacteria growth conditions in a sealed environment to enable chemical inhibition tests with volatile chemicals.

    PubMed

    Johnson, Tylor J; Zahler, Jacob D; Baldwin, Emily L; Zhou, Ruanbao; Gibbons, William R

    2016-07-01

    Cyanobacteria are currently being engineered to photosynthetically produce next-generation biofuels and high-value chemicals. Many of these chemicals are highly toxic to cyanobacteria, thus strains with increased tolerance need to be developed. The volatility of these chemicals may necessitate that experiments be conducted in a sealed environment to maintain chemical concentrations. Therefore, carbon sources such as NaHCO3 must be used for supporting cyanobacterial growth instead of CO2 sparging. The primary goal of this study was to determine the optimal initial concentration of NaHCO3 for use in growth trials, as well as if daily supplementation of NaHCO3 would allow for increased growth. The secondary goal was to determine the most accurate method to assess growth of Anabaena sp. PCC 7120 in a sealed environment with low biomass titers and small sample volumes. An initial concentration of 0.5g/L NaHCO3 was found to be optimal for cyanobacteria growth, and fed-batch additions of NaHCO3 marginally improved growth. A separate study determined that a sealed test tube environment is necessary to maintain stable titers of volatile chemicals in solution. This study also showed that a SYTO® 9 fluorescence-based assay for cell viability was superior for monitoring filamentous cyanobacterial growth compared to absorbance, chlorophyll α (chl a) content, and biomass content due to its accuracy, small sampling size (100μL), and high throughput capabilities. Therefore, in future chemical inhibition trials, it is recommended that 0.5g/L NaHCO3 is used as the carbon source, and that culture viability is monitored via the SYTO® 9 fluorescence-based assay that requires minimum sample size. PMID:27196637

  19. Growth

    NASA Astrophysics Data System (ADS)

    Waag, Andreas

    , molecular beam epitaxy (MBE) delivers high quality ZnMgO-ZnO quantum well structures. Other thin film techniques such as PLD or MOCVD are also widely used. The main problem at present is to consistently achieve reliable p-type doping. For this topic, see also Chap. 5. In the past years, there have been numerous publications on p-type doping of ZnO, as well as ZnO p-n junctions and light emitting diodes (LEDs). However, a lot of these reports are in one way or the other inconsistent or at least incomplete. It is quite clear from optical data that once a reliable hole injection can be achieved, high brightness ZnO LEDs should be possible. In contrast to that expectation, none of the LEDs reported so far shows efficient light emission, as would be expected from a reasonable quality ZnO-based LED. See also Chap. 13. As a matter of fact, there seems to be no generally accepted and reliable technique for p-type doping available at present. The reason for this is the unfavorable position of the band structure of ZnO relative to the vacuum level, with a very low lying valence band. See also Fig. 5.1. This makes the incorporation of electrically active acceptors difficult. Another difficulty is the huge defect density in ZnO. There are many indications that defects play a major role in transport and doping. In order to solve the doping problem, it is generally accepted that the quality of the ZnO material grown by the various techniques needs to be improved. Therefore, the optimization of ZnO epitaxy is thought to play a key role in the further development of this material system. Besides being used as an active material in optoelectronic devices, ZnO plays a major role as transparent contact material in thin film solar cells. Polycrystalline, heavily n-type doped ZnO is used for this, combining a high electrical conductivity with a good optical transparency. In this case, ZnO thin films are fabricated by large area growth techniques such as sputtering. For this and other

  20. 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

  1. 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

  2. Multifactorial optimization of endothelial cell growth using modular synthetic extracellular matrices

    PubMed Central

    Jung, Jangwook P.; Moyano, José V.; Collier, Joel H.

    2012-01-01

    Extracellular matrices (ECMs) are complex materials, containing dozens of macromolecules that are assembled together, thus complicating their optimization towards applications in 3D cell culture or tissue engineering. The natural complexity of ECMs has limited cell-matrix investigations predominantly to experiments where only one matrix component is adjusted at a time, making it difficult to uncover interactions between different matrix components or to efficiently determine optimal matrix compositions for specific desired biological responses. Here we have developed modular synthetic ECMs based on peptide self-assembly whose incorporation of multiple different peptide ligands can be adjusted. The peptides can co-assemble in a wide range of combinations to form hydrogels of uniform morphology and consistent mechanical properties, but with precisely varied mixtures of peptide ligands. The modularity of this system in turn enabled multi-factorial experimental designs for investigating interactions between these ligands and for determining a multi-peptide matrix formulation that maximized endothelial cell growth. In cultures of HUVECs, we observed a previously unknown antagonistic interaction between the laminin-derived peptide YIGSR and RGDS-mediated cell attachment and growth. We also identified an optimized combination of self-assembled peptides bearing the ligands RGDS and IKVAV that led to endothelial cell growth equivalent to that on native full-length fibronectin. Both of these findings would have been challenging to uncover using more traditional one-factor-at-a-time analyses. PMID:21249249

  3. The optimal atmospheric CO2 concentration for the growth of winter wheat (Triticum aestivum).

    PubMed

    Xu, Ming

    2015-07-20

    This study examined the optimal atmospheric CO2 concentration of the CO2 fertilization effect on the growth of winter wheat with growth chambers where the CO2 concentration was controlled at 400, 600, 800, 1000, and 1200 ppm respectively. I found that initial increase in atmospheric CO2 concentration dramatically enhanced winter wheat growth through the CO2 fertilization effect. However, this CO2 fertilization effect was substantially compromised with further increase in CO2 concentration, demonstrating an optimal CO2 concentration of 889.6, 909.4, and 894.2 ppm for aboveground, belowground, and total biomass, respectively, and 967.8 ppm for leaf photosynthesis. Also, high CO2 concentrations exceeding the optima not only reduced leaf stomatal density, length and conductance, but also changed the spatial distribution pattern of stomata on leaves. In addition, high CO2 concentration also decreased the maximum carboxylation rate (Vc(max)) and the maximum electron transport rate (J(max)) of leaf photosynthesis. However, the high CO2 concentration had little effect on leaf length and plant height. The optimal CO2 fertilization effect found in this study can be used as an indicator in selecting and breeding new wheat strains in adapting to future high atmospheric CO2 concentrations and climate change. PMID:26253981

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

    NASA Astrophysics Data System (ADS)

    Gevertz, Jana

    2012-04-01

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

  5. 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

  6. 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.

  7. 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.

  8. An optimal control strategy for crop growth in advanced life support systems.

    PubMed

    Fleisher, D H; Baruh, H

    2001-01-01

    A feedback control method for regulating crop growth in advanced life support systems is presented. Two models for crop growth are considered, one developed by the agricultural industry and used by the Ames Research Center, and a mechanistic model, termed the Energy Cascade model. Proportional and pointwise-optimal control laws are applied to both models using wheat as the crop and light intensity as the control input. The control is particularly sensitive to errors in measurement of crop dry mass. However, it is shown that the proposed approach is a potentially viable way of controlling crop growth as it compensates for model errors and problems associated with applying the desired control input due to environmental disturbances. Grant numbers: NGT5-50229. PMID:11725784

  9. Growth of large size diamond single crystals by plasma assisted chemical vapour deposition: Recent achievements and remaining challenges

    NASA Astrophysics Data System (ADS)

    Tallaire, Alexandre; Achard, Jocelyn; Silva, François; Brinza, Ovidiu; Gicquel, Alix

    2013-02-01

    Diamond is a material with outstanding properties making it particularly suited for high added-value applications such as optical windows, power electronics, radiation detection, quantum information, bio-sensing and many others. Tremendous progresses in its synthesis by microwave plasma assisted chemical vapour deposition have allowed obtaining single crystal optical-grade material with thicknesses of up to a few millimetres. However the requirements in terms of size, purity and crystalline quality are getting more and more difficult to achieve with respect to the forecasted applications, thus pushing the synthesis method to its scientific and technological limits. In this paper, after a short description of the operating principles of the growth technique, the challenges of increasing crystal dimensions both laterally and vertically, decreasing and controlling point and extended defects as well as modulating crystal conductivity by an efficient doping will be detailed before offering some insights into ways to overcome them.

  10. 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.

  11. 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.

  12. 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,…

  13. Monitoring Plasmodium falciparum growth and development by UV flow cytometry using an optimized Hoechst-thiazole orange staining strategy.

    PubMed

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

    2008-06-01

    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

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

    PubMed

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

    2013-09-01

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

  15. 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.

  16. 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.

  17. 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

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

    PubMed

    Cruz-Rivera, Erica; Vasilieva, Olga

    2013-02-01

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

  20. 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.

  1. 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.

  2. 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).

  3. 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.

  4. 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

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

    PubMed Central

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

    2012-01-01

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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Export dynamics as an optimal growth problem in the network of global economy.

    PubMed

    Caraglio, Michele; Baldovin, Fulvio; Stella, Attilio L

    2016-01-01

    We analyze export data aggregated at world global level of 219 classes of products over a period of 39 years. Our main goal is to set up a dynamical model to identify and quantify plausible mechanisms by which the evolutions of the various exports affect each other. This is pursued through a stochastic differential description, partly inspired by approaches used in population dynamics or directed polymers in random media. We outline a complex network of transfer rates which describes how resources are shifted between different product classes, and determines how casual favorable conditions for one export can spread to the other ones. A calibration procedure allows to fit four free model-parameters such that the dynamical evolution becomes consistent with the average growth, the fluctuations, and the ranking of the export values observed in real data. Growth crucially depends on the balance between maintaining and shifting resources to different exports, like in an explore-exploit problem. Remarkably, the calibrated parameters warrant a close-to-maximum growth rate under the transient conditions realized in the period covered by data, implying an optimal self organization of the global export. According to the model, major structural changes in the global economy take tens of years. PMID:27530505

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

    PubMed

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

    2011-07-01

    Anodic aluminium oxide (RAAO) membranes with a mesoporous structure were prepared under strictly controlling experimental process conditions, and physically and chemically characterized by a wide range of experimental techniques. Commercial anodic aluminium oxide (CAAO) membranes were also investigated for comparison. We demonstrated that RAAO membranes have lower content of both water and phosphorus and showed better porosity shape than CAAO. The RAAO membranes were used for template growth of carbon nanotubes (CNT) inside its pores by ethylene chemical vapour deposition (CVD) in the absence of a catalyst. A composite material, containing one nanotube for each channel, having the same length as the membrane thickness and an external diameter close to the diameter of the membrane holes, was obtained. Yield, selectivity and quality of CNTs in terms of diameter, length and arrangement (i.e. number of tubes for each channel) were optimized by investigating the effect of changing the experimental conditions for the CVD process. We showed that upon thermal treatment RAAO membranes were made up of crystallized allotropic alumina phases, which govern the subsequent CNT growth, because of their catalytic activity, likely due to their Lewis acidity. The strict control of experimental conditions for membrane preparation and CNT growth allowed us to enhance the carbon structural order, which is a critical requisite for CNT application as a substitute for copper in novel nano-interconnects. PMID:21576783

  12. Export dynamics as an optimal growth problem in the network of global economy

    PubMed Central

    Caraglio, Michele; Baldovin, Fulvio; Stella, Attilio L.

    2016-01-01

    We analyze export data aggregated at world global level of 219 classes of products over a period of 39 years. Our main goal is to set up a dynamical model to identify and quantify plausible mechanisms by which the evolutions of the various exports affect each other. This is pursued through a stochastic differential description, partly inspired by approaches used in population dynamics or directed polymers in random media. We outline a complex network of transfer rates which describes how resources are shifted between different product classes, and determines how casual favorable conditions for one export can spread to the other ones. A calibration procedure allows to fit four free model-parameters such that the dynamical evolution becomes consistent with the average growth, the fluctuations, and the ranking of the export values observed in real data. Growth crucially depends on the balance between maintaining and shifting resources to different exports, like in an explore-exploit problem. Remarkably, the calibrated parameters warrant a close-to-maximum growth rate under the transient conditions realized in the period covered by data, implying an optimal self organization of the global export. According to the model, major structural changes in the global economy take tens of years. PMID:27530505

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  14. Increase of SiC sublimation growth rate by optimizing of powder packaging

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolin; Cai, Dang; Zhang, Hui

    2007-07-01

    In this paper, a comprehensive model for silicon carbide (SiC) sublimation crystal growth considering powder packaging is presented. This model is based on heat and mass transfer of porous powder charge with different sizes of the particle and accounts for induction heating, powder charge sublimation, vapor transport, and porosity evolution in a SiC sublimation crystal growth system. The mechanism of vapor transport is proposed by introducing a driving force arising from temperature difference between powder charge and seed in the growth system. Powder porosity evolution and sublimation rate variations are predicted based on vapor transport mechanism. Effects of powder geometry, such as particle sizes, volume and size ratios of different particles, and driving forces on the sublimation rate are studied. In addition, simulation results for powder sublimation with and without a central hole are presented. The results indicate that the sublimation rate can be increased by optimizing the powder packaging, or by creating a hole in the center of packed powder.

  15. 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

  16. Optimal Design for Informative Protocols in Xenograft Tumor Growth Inhibition Experiments in Mice.

    PubMed

    Lestini, Giulia; Mentré, France; Magni, Paolo

    2016-09-01

    Tumor growth inhibition (TGI) models are increasingly used during preclinical drug development in oncology for the in vivo evaluation of antitumor effect. Tumor sizes are measured in xenografted mice, often only during and shortly after treatment, thus preventing correct identification of some TGI model parameters. Our aims were (i) to evaluate the importance of including measurements during tumor regrowth and (ii) to investigate the proportions of mice included in each arm. For these purposes, optimal design theory based on the Fisher information matrix implemented in PFIM4.0 was applied. Published xenograft experiments, involving different drugs, schedules, and cell lines, were used to help optimize experimental settings and parameters using the Simeoni TGI model. For each experiment, a two-arm design, i.e., control versus treatment, was optimized with or without the constraint of not sampling during tumor regrowth, i.e., "short" and "long" studies, respectively. In long studies, measurements could be taken up to 6 g of tumor weight, whereas in short studies the experiment was stopped 3 days after the end of treatment. Predicted relative standard errors were smaller in long studies than in corresponding short studies. Some optimal measurement times were located in the regrowth phase, highlighting the importance of continuing the experiment after the end of treatment. In the four-arm designs, the results showed that the proportions of control and treated mice can differ. To conclude, making measurements during tumor regrowth should become a general rule for informative preclinical studies in oncology, especially when a delayed drug effect is suspected. PMID:27306546

  17. 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.

  18. A Study of the Growth Patterns in Language, Communication, and Educational Achievement in Six Residential Schools for Deaf Students.

    ERIC Educational Resources Information Center

    Babbini, Barbara E.; Quigley, Stephen P.

    Communication skills, language abilities, and educational achievement of 163 subjects from six residential schools for deaf students were studied. Subjects were tested yearly from 1963 to 1967 on speechreading, fingerspelling, speech intelligibility, reading achievement, arithmetic achievement, and written language. Both males and females and the…

  19. Optimizing conditions for production of high levels of soluble recombinant human growth hormone using Taguchi method.

    PubMed

    Savari, Marzieh; Zarkesh Esfahani, Sayyed Hamid; Edalati, Masoud; Biria, Davoud

    2015-10-01

    Human growth hormone (hGH) is synthesized and stored by somatotroph cells of the anterior pituitary gland and can effect on body metabolism. This protein can be used to treat hGH deficiency, Prader-Willi syndrome and Turner syndrome. The limitations in current technology for soluble recombinant protein production, such as inclusion body formation, decrease its usage for therapeutic purposes. To achieve high levels of soluble form of recombinant human growth hormone (rhGH) we used suitable host strain, appropriate induction temperature, induction time and culture media composition. For this purpose, 32 experiments were designed using Taguchi method and the levels of produced proteins in all 32 experiments were evaluated primarily by ELISA and dot blotting and finally the purified rhGH protein products assessed by SDS-PAGE and Western blotting techniques. Our results indicate that media, bacterial strains, temperature and induction time have significant effects on the production of rhGH. The low cultivation temperature of 25°C, TB media (with 3% ethanol and 0.6M glycerol), Origami strain and a 10-h induction time increased the solubility of human growth hormone. PMID:26151869

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

    PubMed

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

    2013-01-01

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

  1. 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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  3. Analysis of cell growth dynamics of Pediococcus acidilactici in the presence of inulin in an optimized microenvironment.

    PubMed

    Samanta Koruri, Sharmistha; Chowdhury, Ranjana; Bhattacharya, Pinaki

    2015-09-01

    The present investigation deals with the optimization of cell growth rate of the candidate probiotic Pediococcus acidilactici in the presence of the specific prebiotic inulin. Three independent variables viz. concentration of inulin, concentration of glucose and pH have been selected for optimization study using response surface methodology. Theoretical analysis indicates that the maximum cell growth rate occurs at pH 7, 20 g/dm(3) concentration of inulin and 20 g/dm(3) concentration of glucose. Validation of these values has been done through a set of programmed experiments. Studies on cell dynamics in the presence of different concentrations of inulin have also been carried out to identify any limitation on the initial inulin concentration. Results clearly indicate that cell growth is enhanced with the increase in inulin concentration. However, there is a critical value of the prebiotic concentration (20 g/dm(3) inulin) beyond which the cell growth is inhibited. A summative type growth model has been proposed to explain the growth behaviour of P. acidilactici in the presence of the dual substrate, i.e. glucose and inulin. While growth on glucose follows Monod model, Haldane-type substrate-inhibited growth model holds good for growth on inulin. Intrinsic kinetic parameters for all the model equations have been determined experimentally. PMID:26159350

  4. 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…

  5. 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…

  6. Systematic development and optimization of chemically defined medium supporting high cell density growth of Bacillus coagulans.

    PubMed

    Chen, Yu; Dong, Fengqing; Wang, Yonghong

    2016-09-01

    With determined components and experimental reducibility, the chemically defined medium (CDM) and the minimal chemically defined medium (MCDM) are used in many metabolism and regulation studies. This research aimed to develop the chemically defined medium supporting high cell density growth of Bacillus coagulans, which is a promising producer of lactic acid and other bio-chemicals. In this study, a systematic methodology combining the experimental technique with flux balance analysis (FBA) was proposed to design and simplify a CDM. The single omission technique and single addition technique were employed to determine the essential and stimulatory compounds, before the optimization of their concentrations by the statistical method. In addition, to improve the growth rationally, in silico omission and addition were performed by FBA based on the construction of a medium-size metabolic model of B. coagulans 36D1. Thus, CDMs were developed to obtain considerable biomass production of at least five B. coagulans strains, in which two model strains B. coagulans 36D1 and ATCC 7050 were involved. PMID:27262567

  7. 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.

  8. 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

  9. Optimization of culture conditions to obtain maximal growth of penicillin-resistant Streptococcus pneumoniae

    PubMed Central

    Restrepo, Andrea V; Salazar, Beatriz E; Agudelo, María; Rodriguez, Carlos A; Zuluaga, Andres F; Vesga, Omar

    2005-01-01

    Background Streptococcus pneumoniae, particularly penicillin-resistant strains (PRSP), constitute one of the most important causes of serious infections worldwide. It is a fastidious microorganism with exquisite nutritional and environmental requirements to grow, a characteristic that prevents the development of useful animal models to study the biology of the microorganism. This study was designed to determine optimal conditions for culture and growth of PRSP. Results We developed a simple and reproducible method for culture of diverse strains of PRSP representing several invasive serotypes of clinical and epidemiological importance in Colombia. Application of this 3-step culture protocol consistently produced more than 9 log10 CFU/ml of viable cells in the middle part of the logarithmic phase of their growth curve. Conclusion A controlled inoculum size grown in 3 successive steps in supplemented agar and broth under 5% CO2 atmosphere, with pH adjustment and specific incubation times, allowed production of great numbers of PRSP without untimely activation of autolysis mechanisms. PMID:15932633

  10. OPTIMAL GROWTH CONDITIONS AND ANTIOXIDATIVE ACTIVITIES OF CYLINDROTHECA CLOSTERIUM (BACILLARIOPHYCEAE)(1).

    PubMed

    Affan, Abu; Heo, Soo-Jin; Jeon, You-Jin; Lee, Joon-Baek

    2009-12-01

    We isolated the unialgal strain of Cylindotheca closterium (Ehrenb.) Reimann et J. C. Lewin and produced an axenic strain using an antibiotic cocktail of enriched f/2 artificial seawater medium. The optimal growth conditions were estimated under 27 different combinations of temperature, salinity, and nutrients, and mass culture was performed based on the best specific growth conditions. Its antioxidant activities were determined from the extracts of methanol, water, and enzymes (proteases and carbohydrases). The maximum specific growth rate (μmax ) varied from 0.63 to 0.97 · d(-1) . The maximum cell density was 7.20 × 10(4) cells · mL(-1) , while the μmax was 0.82 · d(-1) in culture conditions of 20°C, 30 psu (practical salinity unit), and "F" nutrient concentrations on day 10 of the culture period. The scavenging rates for 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical were 72.5% and 69.4% from Viscozyme and methanol extracts, respectively. The enzymatic extracts of C. closterium prepared by the hydrolyses of Amyloglucosidase (AMG) and Viscozyme showed 45.8% and 45.5% nitric-oxide-scavenging rates, slightly lower than the activity of alpha-tocopherol (α-tocopherol) but similar to butylated hydroxytoluene (BHT). The extract from methanol and water showed 44.8% and 44.4% scavenging rates, statistically similar with BHT. The metal-chelating activities of the Kojizyme, Alcalase, methanol, Viscozyme, and Neutrase extracts were 67.1, 53.9, 53.2, 52.1, and 50.2 %, respectively, five to six times higher than the commercial antioxidants. The AMG, Viscozyme, and Neutrase extracts showed a remarkable linoleic acid peroxidation inhibition, which was higher than BHT and statistically similar with α-tocopherol. PMID:27032598

  11. 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.

  12. 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

  13. Modelling of salad plants growth and physiological status in vitamin space greenhouse during lighting regime optimization

    NASA Astrophysics Data System (ADS)

    Konovalova, Irina; Berkovich, Yuliy A.; Smolyanina, Svetlana; Erokhin, Alexei; Yakovleva, Olga; Lapach, Sergij; Radchenko, Stanislav; Znamenskii, Artem; Tarakanov, Ivan

    2016-07-01

    The efficiency of the photoautotrophic element as part of bio-engineering life-support systems is determined substantially by lighting regime. The artificial light regime optimization complexity results from the wide range of plant physiological functions controlled by light: trophic, informative, biosynthetical, etc. An average photosynthetic photon flux density (PPFD), light spectral composition and pulsed light effects on the crop growth and plant physiological status were studied in the multivariate experiment, including 16 independent experiments in 3 replicates. Chinese cabbage plants (Brassica chinensis L.), cultivar Vesnianka, were grown during 24 days in a climatic chamber under white and red light-emitting diodes (LEDs): photoperiod 24 h, PPFD from 260 to 500 µM/(m ^{2}*s), red light share in the spectrum varying from 33% to 73%, pulsed (pulse period from 30 to 501 µs) and non-pulsed lighting. The regressions of plant photosynthetic and biochemical indexes as well as the crop specific productivity in response to the selected parameters of lighting regime were calculated. Developed models of crop net photosynthesis and dark respiration revealed the most intense gas exchange area corresponding to PPFD level 450 - 500 µM/(m ^{2}*s) with red light share in the spectrum about 60% and the pulse length 30 µs with a pulse period from 300 to 400 µs. Shoot dry weight increased monotonically in response to the increasing PPFD and changed depending on the pulse period under stabilized PPFD level. An increase in ascorbic acid content in the shoot biomass was revealed when increasing red light share in spectrum from 33% to 73%. The lighting regime optimization criterion (Q) was designed for the vitamin space greenhouse as the maximum of a crop yield square on its ascorbic acid concentration, divided by the light energy consumption. The regression model of optimization criterion was constructed based on the experimental data. The analysis of the model made it

  14. 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

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

    PubMed

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

    2009-08-01

    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

  16. 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

  17. 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

  18. 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

  19. Optimal myelin elongation relies on YAP activation by axonal growth and inhibition by Crb3/Hippo pathway.

    PubMed

    Fernando, Ruani N; Cotter, Laurent; Perrin-Tricaud, Claire; Berthelot, Jade; Bartolami, Sylvain; Pereira, Jorge A; Gonzalez, Sergio; Suter, Ueli; Tricaud, Nicolas

    2016-01-01

    Fast nerve conduction relies on successive myelin segments that electrically isolate axons. Segment geometry-diameter and length-is critical for the optimization of nerve conduction and the molecular mechanisms allowing this optimized geometry are partially known. We show here that peripheral myelin elongation is dynamically regulated by stimulation of YAP (Yes-associated protein) transcription cofactor activity during axonal elongation and limited by inhibition of YAP activity via the Hippo pathway. YAP promotes myelin and non-myelin genes transcription while the polarity protein Crb3, localized at the tips of the myelin sheath, activates the Hippo pathway to temper YAP activity, therefore allowing for optimal myelin growth. Dystrophic Dy(2j/2j) mice mimicking human peripheral neuropathy with reduced internodal lengths have decreased nuclear YAP which, when corrected, leads to longer internodes. These data show a novel mechanism controlling myelin growth and nerve conduction, and provide a molecular ground for disease with short myelin segments. PMID:27435623

  20. Optimal myelin elongation relies on YAP activation by axonal growth and inhibition by Crb3/Hippo pathway

    PubMed Central

    Fernando, Ruani N.; Cotter, Laurent; Perrin-Tricaud, Claire; Berthelot, Jade; Bartolami, Sylvain; Pereira, Jorge A.; Gonzalez, Sergio; Suter, Ueli; Tricaud, Nicolas

    2016-01-01

    Fast nerve conduction relies on successive myelin segments that electrically isolate axons. Segment geometry—diameter and length—is critical for the optimization of nerve conduction and the molecular mechanisms allowing this optimized geometry are partially known. We show here that peripheral myelin elongation is dynamically regulated by stimulation of YAP (Yes-associated protein) transcription cofactor activity during axonal elongation and limited by inhibition of YAP activity via the Hippo pathway. YAP promotes myelin and non-myelin genes transcription while the polarity protein Crb3, localized at the tips of the myelin sheath, activates the Hippo pathway to temper YAP activity, therefore allowing for optimal myelin growth. Dystrophic Dy2j/2j mice mimicking human peripheral neuropathy with reduced internodal lengths have decreased nuclear YAP which, when corrected, leads to longer internodes. These data show a novel mechanism controlling myelin growth and nerve conduction, and provide a molecular ground for disease with short myelin segments. PMID:27435623

  1. Rod Visual Pigment Optimizes Active State to Achieve Efficient G Protein Activation as Compared with Cone Visual Pigments*

    PubMed Central

    Kojima, Keiichi; Imamoto, Yasushi; Maeda, Ryo; Yamashita, Takahiro; Shichida, Yoshinori

    2014-01-01

    Most vertebrate retinas contain two types of photoreceptor cells, rods and cones, which show different photoresponses to mediate scotopic and photopic vision, respectively. These cells contain different types of visual pigments, rhodopsin and cone visual pigments, respectively, but little is known about the molecular properties of cone visual pigments under physiological conditions, making it difficult to link the molecular properties of rhodopsin and cone visual pigments with the differences in photoresponse between rods and cones. Here we prepared bovine and mouse rhodopsin (bvRh and mRh) and chicken and mouse green-sensitive cone visual pigments (cG and mG) embedded in nanodiscs and applied time-resolved fluorescence spectroscopy to compare their Gt activation efficiencies. Rhodopsin exhibited greater Gt activation efficiencies than cone visual pigments. Especially, the Gt activation efficiency of mRh was about 2.5-fold greater than that of mG at 37 °C, which is consistent with our previous electrophysiological data of knock-in mice. Although the active state (Meta-II) was in equilibrium with inactive states (Meta-I and Meta-III), quantitative determination of Meta-II in the equilibrium showed that the Gt activation efficiency per Meta-II of bvRh was also greater than those of cG and mG. These results indicated that efficient Gt activation by rhodopsin, resulting from an optimized active state of rhodopsin, is one of the causes of the high amplification efficiency of rods. PMID:24375403

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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...

  8. Strategies to optimize lithium-ion supercapacitors achieving high-performance: Cathode configurations, lithium loadings on anode, and types of separator

    NASA Astrophysics Data System (ADS)

    Cao, Wanjun; Li, Yangxing; Fitch, Brian; Shih, Jonathan; Doung, Tien; Zheng, Jim

    2014-12-01

    The Li-ion capacitor (LIC) is composed of a lithium-doped carbon anode and an activated carbon cathode, which is a half Li-ion battery (LIB) and a half electrochemical double-layer capacitor (EDLC). LICs can achieve much more energy density than EDLC without sacrificing the high power performance advantage of capacitors over batteries. LIC pouch cells were assembled using activated carbon (AC) cathode and hard carbon (HC) + stabilized lithium metal power (SLMP®) anode. Different cathode configurations, various SLMP loadings on HC anode, and two types of separators were investigated to achieve the optimal electrochemical performance of the LIC. Firstly, the cathode binders study suggests that the PTFE binder offers improved energy and power performances for LIC in comparison to PVDF. Secondly, the mass ratio of SLMP to HC is at 1:7 to obtain the optimized electrochemical performance for LIC among all the various studied mass ratios between lithium loading amounts and active anode material. Finally, compared to the separator Celgard PP 3501, cellulose based TF40-30 is proven to be a preferred separator for LIC.

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  10. 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.