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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 individual epiphyseal plates. PMID:26241802

  2. 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…

  3. 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…

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

    ERIC Educational Resources Information Center

    Bacolod, Marigee P.; Tobias, Justin L.

    2006-01-01

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

  5. 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.…

  6. 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.

  7. Efficient Secret Sharing Schemes Achieving Optimal Information Rate

    E-print Network

    Wang, Yongge

    Efficient Secret Sharing Schemes Achieving Optimal Information Rate Yongge Wang KINDI Center problems in secret sharing schemes is to establish bounds on the size of the shares to be given to participants in secret sharing schemes. The other important problem in secret sharing schemes is to reduce

  8. 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

  9. Adaptation to Optimal Cell Growth through Self-Organized Criticality

    NASA Astrophysics Data System (ADS)

    Furusawa, Chikara; Kaneko, Kunihiko

    2012-05-01

    A simple cell model consisting of a catalytic reaction network is studied to show that cellular states are self-organized in a critical state for achieving optimal growth; we consider the catalytic network dynamics over a wide range of environmental conditions, through the spontaneous regulation of nutrient transport into the cell. Furthermore, we find that the adaptability of cellular growth to reach a critical state depends only on the extent of environmental changes, while all chemical species in the cell exhibit correlated partial adaptation. These results are in remarkable agreement with the recent experimental observations of the present cells.

  10. 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…

  11. Limits of optimal control yields achievable with quantum controllers

    E-print Network

    Re-Bing Wu; Constantin Brif; Matthew R. James; Herschel Rabitz

    2015-05-03

    In quantum optimal control theory, kinematic bounds are the minimum and maximum values of the control objective achievable for any physically realizable system dynamics. For a given initial state of the system, these bounds depend on the nature and state of the controller. We consider a general situation where the controlled quantum system is coupled to both an external classical field (referred to as a classical controller) and an auxiliary quantum system (referred to as a quantum controller). In this general situation, the kinematic bound is between the classical kinematic bound (CKB), corresponding to the case when only the classical controller is available, and the quantum kinematic bound (QKB), corresponding to the ultimate physical limit of the objective's value. Specifically, when the control objective is the expectation value of a quantum observable (a Hermitian operator on the system's Hilbert space), the QKBs are the minimum and maximum eigenvalues of this operator. We present, both qualitatively and quantitatively, the necessary and sufficient conditions for surpassing the CKB and reaching the QKB, through the use of a quantum controller. The general conditions are illustrated by examples in which the system and controller are initially in thermal states. The obtained results provide a basis for the design of quantum controllers capable of maximizing the control yield and reaching the ultimate physical limit.

  12. 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.

  13. 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…

  14. 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

  15. 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…

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  17. 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…

  18. 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.…

  19. Optimizing Production of Hydroquinone Achieves Increased Yield and Energy Efficiency 

    E-print Network

    Gross, S.

    2010-01-01

    , build inventory, then take extended shutdowns to control inventory to acceptable levels ? Payoff: Significant energy reduction, yield improvement and optimized operating costs Project definition ? Risk assessment ? In order to move past the cultural... ? Amount of HQ produced in one year ? Year end inventory ? Energy Savings: compared 2009 electricity and steam usage to that of 2008 ? Manufacturing Cost Reporting (SAP) Results ? Energy Savings ? Reduction in steam and electricity usage: ? Steam: 88...

  20. 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.

  1. 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.

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

    PubMed Central

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

    2002-01-01

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

  3. Achieving and documenting closure in plant growth facilities

    NASA Astrophysics Data System (ADS)

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

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

  4. 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.

  5. Optimization of heating conditions during Cz BGO crystal growth

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  9. Multiphase Nano-Composite Coatings for Achieving Energy Optimization

    SciTech Connect

    Dr. Jose Nainaparampil

    2012-03-26

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

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

    E-print Network

    Osu, Rieko

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

  11. 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…

  12. 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…

  13. 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…

  14. 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...

  15. Growth parameter optimization for fast quantum dot SESAMs

    E-print Network

    Keller, Ursula

    Growth parameter optimization for fast quantum dot SESAMs D. J. H. C. Maas,* A.-R. Bellancourt, M: maas@phys.ethz.ch Abstract: Semiconductor saturable absorber mirrors (SESAMs) using quantum dot (QD and post growth annealing on the macroscopic optical SESAM parameters, measuring both nonlinear

  16. Optimal Conditions for the Mycelial Growth of Coprinus comatus Strains

    PubMed Central

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

    2009-01-01

    The principal objective of this study was to acquire basic data regarding the mycelial growth characteristics for the artificial cultivation of Coprinus comatus. 12 URP primers were employed to evaluate the genetic relationships of C. comatus, and the results were divided into three groups. Among six kinds of mushroom media, MYP medium was selected as the most favorable culture medium for C. comatus. The optimal temperature and pH ranges for the mycelial growth of C. comatus were 23~26? and pH 6~8, respectively. The carbon and nitrogen sources for optimal mycelial growth were sucrose and tryptone, respectively. PMID:23983517

  17. 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.

  18. Optimal linear growth in MHD duct flow

    NASA Astrophysics Data System (ADS)

    Boeck, Thomas; Krasnov, Dmitry; Rossi, Maurice; Zikanov, Oleg

    2008-11-01

    We consider the flow of an electrically conducting fluid in a rectangular duct under a homogeneous magnetic field. The field is perpendicular to the flow direction and parallel to one set of the non-conducting walls. Our focus is on the transient growth of linear perturbations as a prerequisite for subsequent numerical studies of subcritical transition in the MHD duct flow. The perturbations with strongest transient growth are obtained by an iterative method based on linearized perturbation equations and their adjoint equations. We study the effect of the magnetic induction and of the aspect ratio of the duct on the maximum energy amplification and on the corresponding spatial structure of the linear perturbations. For wide ducts with magnetic field perpendicular to the long walls we find considerable differences to the periodic channel with wall-normal magnetic field. For narrow ducts the agreement with the periodic channel with spanwise magnetic field is considerably better.

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

    ERIC Educational Resources Information Center

    Guvercin, Mustafa

    2013-01-01

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

  20. 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

  1. 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…

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

    NASA Astrophysics Data System (ADS)

    Muller, Patricia Ann

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

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

    ERIC Educational Resources Information Center

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

    2004-01-01

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

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

    PubMed Central

    Geary, David C.

    2011-01-01

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

  5. The MBE growth and optimization of high performance terahertz frequency quantum cascade lasers.

    PubMed

    Li, L H; Zhu, J X; Chen, L; Davies, A G; Linfield, E H

    2015-02-01

    The technique of molecular beam epitaxy has recently been used to demonstrate the growth of terahertz frequency GaAs/AlGaAs quantum cascade lasers (QCL) with Watt-level optical output powers. In this paper, we discuss the critical importance of achieving accurate layer thicknesses and alloy compositions during growth, and demonstrate that precise growth control as well as run-to-run growth reproducibility is possible. We also discuss the importance of minimizing background doping level in maximizing QCL performance. By selecting high-performance active region designs, and optimizing the injection doping level and device fabrication, we demonstrate total optical (two-facet) output powers as high as 1.56 W. PMID:25836134

  6. Achieving optimal model complexity through objective selection and simplification of alternative structures

    NASA Astrophysics Data System (ADS)

    van Dijk, Albert I. J. M.

    2010-05-01

    A formal method was developed to achieve optimal model complexity where alternative conceptual structures exist or there are several free model parameters. The method was applied to alternative lumped model structures for surface runoff prediction and for baseflow recession estimation, respectively. The objective performance measure is based on Aikake's Information Criterion (AIC), which attempts to account for the effect of the number of free parameters in the calculation of model prediction error. Model simplification involves stepwise reduction of the least important free parameters, either by removing it or replacing it by a single prior estimate. The model with the optimal performance among all structures and variants is selected as having the optimal trade-off between model complexity and parsimony. Caveats of the method are associated with the assumptions in the AIC model, how telling the used error statistic is, and how representative the data available for performance assessment.

  7. 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.

  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. 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 the middle position of the third furnace.

  10. 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.

  11. 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.

  12. Growth–Defense Tradeoffs in Plants: A Balancing Act to Optimize Fitness

    PubMed Central

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

    2014-01-01

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

  13. Perceived social support and academic achievement: cross-lagged panel and bivariate growth curve analyses.

    PubMed

    Mackinnon, Sean P

    2012-04-01

    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 disentangle the direction of relationships. This study uses a cross-lagged panel and a bivariate growth curve analysis with a three-wave longitudinal design. Participants include 10,445 students (56% female; 12.6% born outside of Canada) transitioning to post-secondary education from ages 15-19. Self-report measures of academic achievement and a generalized measure of perceived social support were used. An increase in average relative standing in academic achievement predicted an increase in average relative standing on perceived social support 2 years later, but the reverse was not true. High levels of perceived social support at age 15 did not protect against declines in academic achievement over time. In sum, perceived social support appears to have no bearing on adolescents' future academic performance, despite commonly held assumptions of its importance. PMID:21720859

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

    SciTech Connect

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

    2000-11-16

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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Legionella pneumophilaRequires Polyamines for Optimal Intracellular Growth ?

    PubMed Central

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

  1. 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.

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

    PubMed

    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. PMID:15880901

  3. 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.

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  5. 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

  6. Optimizing light regimes on growth and lipid accumulation in Ankistrodesmus fusiformis H1 for biodiesel production.

    PubMed

    He, Qiaoning; Yang, Haijian; Hu, Chunxiang

    2015-12-01

    The aim of this study was to optimize the light regimes including initial inoculum density, photoperiod and light intensity on the growth and lipid (TAG) accumulation in Ankistrodesmus fusiformis H1 for biodiesel production. At last, the strategy of 4.47mM urea with initial OD680-0.5, 18:6h light/dark cycle and 200?molphotonm(-2)s(-1) regimes were optimized. The lipid productivity of 116.88mgL(-1)d(-1) and 57.58% neutral lipid in total lipid were achieved finally. Moreover, the changes of photosynthetic activity, pigments contents and biochemical compositions revealed that more carbon flow to lipid synthesis. Therefore, A. fusiformis H1 is an ideal candidate for biodiesel production by utilizing light appropriately. PMID:26469216

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  9. 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.

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

    PubMed Central

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

    2014-01-01

    Executive functioning (EF) is examined among children and adolescents once diagnosed with an autism spectrum disorder (ASD), but who no longer meet diagnostic criteria. These individuals have average social and language skills, receive minimal school support and are considered to have achievedoptimal outcomes” (OOs). Since residual impairments in these individuals might be expected in deficits central to autism, and in developmentally advanced skills, EF was examined in: 34 individuals who achieved OOs, 43 individuals with high-functioning autism (HFA), and 34 typically-developing (TD) peers. Groups were matched on age (M=13.49), gender, and NVIQ, but differed on VIQ (HFA

  11. Growth and academic achievement in inner-city kindergarten children. The relationship of height, weight, cognitive ability, and neurodevelopmental level.

    PubMed

    Karp, R; Martin, R; Sewell, T; Manni, J; Heller, A

    1992-06-01

    Measures of height, weight, nonverbal cognitive ability (Ravens progressive matrix), visual-motor-perceptual ability (Beery-Buktenica test of Visual Motor Integration [VMI]), the imitation-of-gestures technique, and academic achievement (Stanford Early Achievement) were obtained for a sample of 82 children from a poor inner-city community. In contrast to prior reports from the United States and about other developed countries, anthropometric measures were related both to academic achievement and to these measures of neurodevelopment. They were not consistently related to measures of nonverbal cognitive ability. Regression analyses revealed that general cognitive ability contributed more variance (39%) to predictions of achievement than all other variables, including weight for age (13%) and VMI (6%). Children with reduced somatic growth were likely to do poorly in school, but the data do not show that undernutrition causes learning failure. Rather, they suggest that environmental problems affecting the development of thought processes and nutrient intake precede both growth and learning failure. PMID:1628466

  12. 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

  13. 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…

  14. 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

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

    NASA Astrophysics Data System (ADS)

    Jones, Scott B.; Or, Dani

    1998-11-01

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

  16. 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.

  17. electrodes, and (iii) an output collimator. To achieve optimal performance, the whole modulator, including the input collimator,

    E-print Network

    Cao, Wenwu

    in rectangular dielec- tric resonators (DRs). Three-dimensional field patterns for these modes are derivedelectrodes, and (iii) an output collimator. To achieve optimal performance, the whole modulator 10.1002/mop. 10708 Key words: finite-difference time-domain method (FDTD); dielectric resonators

  18. 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;…

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

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  20. 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…

  1. 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.

  2. MOCVD optimized growth for laser diodes emitting at 980nm via photoluminescence

    NASA Astrophysics Data System (ADS)

    Li, Jianjun; He, Linjie; Lin, Shengjie; Han, Jun; Deng, Jun

    2014-07-01

    We have investigated different growth conditions of AlGaAs and InGaAs quantum wells (QWs) by metal organic chemical vapor deposition (MOCVD) for applications in high-power laser diodes emitting at 980nm. According to different experimental results measured by Photoluminescence (PL), we optimized the growth conditions. Growth temperature, V/III ratio, growth interruption and spacer time have been studied in detail. We have found the optimal growth conditions for laser diodes emitting at 980nm grown by metal organic chemical vapor deposition (MOCVD). As for our experiments, the best suitable growth temperature of AlGaAs and InGaAs QWs was 700°C and 600°C, respectively. The growth procedure of laser diodes should include growth interruption and spacer layers surrounding QWs. V/III ratio was about 130 during the growth of QWs.

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

    E-print Network

    Lieth, J. Heinrich

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

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

    PubMed

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

    2014-11-01

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

  5. 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…

  6. Growth of aligned carbon nanotubes by plasma-enhanced chemical vapor deposition: Optimization of growth parameters

    NASA Astrophysics Data System (ADS)

    Tanemura, M.; Iwata, K.; Takahashi, K.; Fujimoto, Y.; Okuyama, F.; Sugie, H.; Filip, V.

    2001-08-01

    Direct-current plasma-enhanced chemical vapor deposition (CVD) with mixtures of acetylene and ammonia was optimized to synthesize aligned carbon nanotubes (CNTs) on Co- or Ni-covered W wires with regard to wire temperature, wire diameter, gas pressure, and sample bias. A phase diagram of CNT growth was established experimentally in this optimization process. It was revealed by transmission electron microscopy that Co-catalyzed CNTs encapsulated a Co carbide nanoparticle at their tip, disagreeing with a previous report that Co particles were located at the base of CNTs CVD grown on Co-covered Si substrates [C. Bower et al., Appl. Phys. Lett. 77, 2767 (2000)]. This leads to the conclusion that the formation mechanism of aligned CNTs depends significantly on the catalyst support material as well as the catalyst material itself. Since the sample bias strongly affected the morphology of CNTs, the selective supply of positive ions to CNT tips was possibly responsible for the alignment of growing CNTs.

  7. 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…

  8. 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…

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

    E-print Network

    Chen, Yiling

    Epstein-Barr virus exploits intrinsic B-lymphocyte transcription programs to achieve immortal cell for resting B-lymphocyte (RBL) conversion to immortal lymphoblast cell lines (LCLs). ChIP-seq of EBNA2

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

    E-print Network

    Yang, Yung-Hun

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

  11. 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…

  12. 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...

  13. 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…

  14. 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…

  15. 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…

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

    ERIC Educational Resources Information Center

    Hinkle, Rachelle Whittaker

    2011-01-01

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

  17. 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…

  18. 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…

  19. 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…

  20. 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…

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  2. Achieving high mobility ZnO : Al at very high growth rates by dc filtered cathodic arc deposition

    NASA Astrophysics Data System (ADS)

    Mendelsberg, R. J.; Lim, S. H. N.; Zhu, Y. K.; Wallig, J.; Milliron, D. J.; Anders, A.

    2011-06-01

    Achieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500-1300 nm thick and highly transparent ZnO : Al films were grown on glass at rates exceeding 250 nm min-1 while maintaining resistivity below 5 × 10-4 ? cm with electron mobility as high as 60 cm2 V-1 s-1.

  3. ORIGINAL ARTICLE Statistical optimization of growth media for Paecilomyces

    E-print Network

    Mittal, Aditya

    optimized for obtaining high production of bio- mass and spores of a biocontrol agent, the entomopathogenic of Paecilomyces lilacinus as a biocontrol agent has been reported to control root-knot nematodes, greenhouse

  4. Achieving Optimal Solution of Linear Programming Based on Mobile Agent Technology

    NASA Astrophysics Data System (ADS)

    Ma, Guo-feng; Yang, Jun-hong; Zhang, Ping-chuan

    Linear programming is an important solution for engineering applications, and sometimes the integer value is needed for the applications, this paper introduced the third distributed computation technology namely Mobile Agent to the linear programming problems, designed the algorithm with low time complexity compared to the traditional method, clarified the method of seeking the optimization in linear programming by means of Mobile Agent,and it's very valuable and practicable.

  5. 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.

  6. 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

  7. 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.

  8. THE COUPLING OF OPTIMAL ECONOMIC GROWTH AND CLIMATE DYNAMICS

    E-print Network

    Edwards, Neil

    economic growth programs coupled with climate change dynamics. The study is based on models derived from climate model, allow us to identity a domain intended to preserve the Atlantic thermohaline circulation of MERGE and an intermediate complexity "3-D" climate model (C-GOLDSTEIN) which computes the changes

  9. Inoculum optimization of Clostridium beijerinckii for reproducible growth.

    PubMed

    Sandoval-Espinola, Walter J; Chinn, Mari; Bruno-Barcena, Jose M

    2015-10-01

    Spore-forming solventogenic Clostridium spp. are receiving renewed attention due to their butanol production abilities. However, there is an absence of literature describing the preparation of dense, vigorous and homogeneous seed cultures of Clostridium spp., guaranteeing reproducibility during fermentation. Therefore, we performed a series of growth experiments of Clostridium beijerinckii NCIMB 8052 and its offspring SA-1 to evaluate the influence of inoculum age (harvest time) on the subsequent population's maximum specific growth rate, as a signal of population homogeneity. The organisms were cultivated in Reinforced Clostridial Medium and supplemented sweet sorghum juice. The best inoculum ages coincided with the late-exponential growth phase: between 9 and 11 h in the conditions tested. Additionally, the harvest time was delayed up to 4 h by pre-adapting the seed culture with 0.75 g L(-1) butyric acid. These findings were validated by performing a series of bench-top batch fermentations showcasing reproducibility in growth kinetics with 95% confidence limits. Overall, these experiments allowed us to understand the transient nature of seed cultures of C. beijerinckii NCIMB 8052 and SA-1, while enabling reproducibility and consistent culture performance. PMID:26363015

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

    PubMed Central

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

    2012-01-01

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

  11. Study on growth optimization and metallization of AlN thin films

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  12. 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

  13. 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

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

    SciTech Connect

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

    2011-02-15

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

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

    PubMed Central

    2013-01-01

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

  16. 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

  17. 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

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

    E-print Network

    Kaneko, Kunihiko

    Adaptation to Optimal Cell Growth through Self-Organized Criticality Chikara Furusawa Quantitative the spontaneous regulation of nutrient transport into the cell. Furthermore, we find that the adaptability chemical species in the cell exhibit correlated partial adaptation. These results are in remarkable

  19. 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 signi?cance 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

  20. 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.

  1. 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

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

    ERIC Educational Resources Information Center

    Chiu, Pui Chi

    2012-01-01

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

  3. 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.

  4. 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.

  5. High-density spore production of Piriformospora indica, a plant growth-promoting endophyte, by optimization of nutritional and cultural parameters.

    PubMed

    Kumar, Vinod; Sahai, Vikram; Bisaria, V S

    2011-02-01

    Piriformospora indica is an axenically cultivable root endophytic fungus which exerts plant growth promoting effects on its host plants. To enable commercial production of its spores, the medium composition and culture conditions have been optimized in a 14 L bioreactor such that they result in maximum biomass during growth phase and in maximum spore yield during subsequent sporulation phase. Maximum spore yields were obtained with modified Kaefer medium using a glucose deprivation strategy. An enhancement of 100% in overall biomass productivity (0.18 g L(-1) h(-1)) and reduction of about 70% in the time (60 h) required to achieve the maximum spore yield (9.25×10(7) spores/mL) was achieved in comparison to the original Kaefer medium. The high spore yield obtained in the present study seems to be economical for commercial production of P. indica. PMID:21095631

  6. 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

  7. 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.

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

    E-print Network

    Suardin, Jaffee Arizon

    2006-10-30

    The integration of the safety parameter into process design and optimization is essential. However, there is no previous work in integrating the fire and explosion index (F&EI) into design and optimization. This research proposed a procedure...

  9. 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.

  10. Optimization of ZnSe film growth conditions for p-type doping

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaojun; Beres, Matthew; Ma, Zhixun; Mao, Samuel S.

    2014-02-01

    Wide bandgap semiconductors such as ZnSe and ZnO have attracted great interest due to their applications in solar cells, light emitting diodes, and lasers. However, these wide bandgap semiconductors are frequently difficult to be doped to heavy concentrations, greatly limiting their application. A substrate holder with a natural temperature gradient was developed for batch growth of films at different deposition temperatures, in order to investigate ZnSe film growth and doping challenges. Thin ZnSe films were grown by pulsed laser deposition and characterized using X-ray diffraction, optical transmission and reflection, Raman spectroscopy, and Energy Dispersive X-ray analysis. Deposition temperature and film stoichiometry (Zn:Se) are shown to be significant factors affecting ZnSe growth and doping. ZnSe films with improved crystallinity have been obtained by enriching with selenium and depositing at an optimized temperature. Heavily p-type ZnSe films with hole concentrations of ~2.7 × 1019 cm-3 and resistivities of ~0.099 Ohm cm have been obtained (compared with previous reports of ~1 × 1018 cm-3 and ~0.75 Ohm cm). The results, which are consistent with previous theoretical prediction of compensating defects in ZnSe films, can help to optimize ZnSe growth conditions and understand doping challenges in wide bandgap semiconductors.

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

    PubMed Central

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

    2009-01-01

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

  12. Comparison of Three Growth Modeling Techniques in the Multilevel Analysis of Longitudinal Academic Achievement Scores: Latent Growth Modeling, Hierarchical Linear Modeling, and Longitudinal Profile Analysis via Multidimensional Scaling

    ERIC Educational Resources Information Center

    Shin, Tacksoo

    2007-01-01

    This study introduces three growth modeling techniques: latent growth modeling (LGM), hierarchical linear modeling (HLM), and longitudinal profile analysis via multidimensional scaling (LPAMS). It compares the multilevel growth parameter estimates and potential predictor effects obtained using LGM, HLM, and LPAMS. The purpose of this multilevel…

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

    PubMed

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    E-print Network

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

    2009-01-01

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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Gharagozloo, P. E.

    2014-12-01

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

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

    PubMed

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

    2015-04-01

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

  5. 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...

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

    ERIC Educational Resources Information Center

    Guglielmi, R. Sergio

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Tiller, Michael M.

    1995-01-01

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

  8. 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

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

    PubMed Central

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

    2009-01-01

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

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

    PubMed

    Leu, Jyh-Yih; Lin, Yen-Hui

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2012-04-11

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

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

    SciTech Connect

    Wayne Penrod; David Moyeda

    2003-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Miyauchi, T.; Machimura, T.

    2013-12-01

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

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

    SciTech Connect

    David Shropshire

    2009-09-01

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

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

    SciTech Connect

    Jeganathan, K.; Shimizu, M.

    2014-09-15

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

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

    NASA Astrophysics Data System (ADS)

    Jeganathan, K.; Shimizu, M.

    2014-09-01

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

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

    SciTech Connect

    Wayne Penrod; David Moyeda

    2003-04-01

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

  3. Testing the optimal defense theory and the growth-differentiation balance hypothesis in Arabidopsis thaliana.

    PubMed

    Barto, E Kathryn; Cipollini, Don

    2005-12-01

    Two prominent theories proposed to explain patterns of chemical defense expression in plants are the optimal defense theory (ODT) and the growth-differentiation balance hypothesis (GDBH). The ODT predicts that plant parts with high fitness value will be highly defended, and the GDBH predicts that slow growing plant parts will have more resources available for defense and thus will have higher defense levels than faster growing tissues. We examined growth rate, fitness value, and defense protein levels in leaves of a wild and lab ecotype of Arabidopsis thaliana to address whether patterns of defense protein expression in this plant conform to predictions of either the ODT or the GDBH. We divided leaves of A. thaliana into six leaf classes based on three developmental stages: vegetative, bolting, and flowering; with two leaf ages at each stage: young and old. We assessed the fitness value of leaves by determining the impact of the removal of each leaf class on total seed production and germination rates. Although A. thaliana was highly tolerant to defoliation, young leaves were more valuable than old in general, and young leaves on bolting plants were the most valuable leaf class in particular. Young leaves on vegetative plants grew fastest in both ecotypes, while old leaves on bolting and flowering plants grew slowest. Finally, defense levels were assessed in each leaf class by quantifying the constitutive and inducible expression of four defense-related proteins. Expression of guaiacol peroxidase and chitinase activity conformed largely to GDBH predictions. Expression of trypsin inhibitor and polyphenoloxidase activity varied by leaf class and treatment, but conformed to neither GDBH nor ODT predictions. PMID:16096848

  4. Optimization of Molecular Beam Epitaxy (MBE) Growth for the Development of Mid-Infrared (IR) II-VI Quantum Cascade Lasers

    NASA Astrophysics Data System (ADS)

    Moug, R. T.; Sultana, H.; Yao, Y.; Alfaro-Martinez, A.; Peng, L.; Garcia, T.; Shen, A.; Gmachl, C.; Tamargo, M. C.

    2012-05-01

    Quantum cascade (QC) lasers operating in the mid-infrared (IR) are being intensely pursued for environmental sensing and other important technological applications. Having demonstrated mid-IR (3 ?m to 5 ?m) electroluminescence (EL) from a II-VI intersubband device based on wide-band-gap (2.9 eV) Zn0.24Cd0.26Mg0.5Se on InP, there has been a drive towards production of a QC laser from these materials. To achieve lasing, waveguiding layers that straddle the active region used in the EL structure must be included. Initial attempts to grow this more complex structure resulted in degradation of the material quality. This paper presents the optimization steps required for the growth of the full QC laser structure and discusses possible mechanisms for the degraded quality.

  5. 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.

  6. Surface stability and the selection rules of substrate orientation for optimal growth of epitaxial II-VI semiconductors

    NASA Astrophysics Data System (ADS)

    Yin, Wan-Jian; Yang, Ji-Hui; Zaunbrecher, Katherine; Gessert, Tim; Barnes, Teresa; Yan, Yanfa; Wei, Su-Huai

    2015-10-01

    The surface structures of ionic zinc-blende CdTe (001), (110), (111), and (211) surfaces are systematically studied by first-principles density functional calculations. Based on the surface structures and surface energies, we identify the detrimental twinning appearing in molecular beam epitaxy (MBE) growth of II-VI compounds as the (111) lamellar twin boundaries. To avoid the appearance of twinning in MBE growth, we propose the following selection rules for choosing optimal substrate orientations: (1) the surface should be nonpolar so that there is no large surface reconstructions that could act as a nucleation center and promote the formation of twins; (2) the surface structure should have low symmetry so that there are no multiple equivalent directions for growth. These straightforward rules, in consistent with experimental observations, provide guidelines for selecting proper substrates for high-quality MBE growth of II-VI compounds.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Reconstruction of ancestral 16S rRNA reveals mutation bias in the evolution of optimal growth temperature in the Thermotogae phylum.

    PubMed

    Green, Anna G; Swithers, Kristen S; Gogarten, Jan F; Gogarten, Johann Peter

    2013-11-01

    Optimal growth temperature is a complex trait involving many cellular components, and its physiology is not yet fully understood. Evolution of continuous characters, such as optimal growth temperature, is often modeled as a one-dimensional random walk, but such a model may be an oversimplification given the complex processes underlying the evolution of continuous characters. Recent articles have used ancestral sequence reconstruction to infer the optimal growth temperature of ancient organisms from the guanine and cytosine content of the stem regions of ribosomal RNA, allowing inferences about the evolution of optimal growth temperature. Here, we investigate the optimal growth temperature of the bacterial phylum Thermotogae. Ancestral sequence reconstruction using a nonhomogeneous model was used to reconstruct the stem guanine and cytosine content of 16S rRNA sequences. We compare this sequence reconstruction method with other ancestral character reconstruction methods, and show that sequence reconstruction generates smaller confidence intervals and different ancestral values than other reconstruction methods. Unbiased random walk simulation indicates that the lower temperature members of the Thermotogales have been under directional selection; however, when a simulation is performed that takes possible mutations into account, it is the high temperature lineages that are, in fact, under directional selection. We find that the evolution of Thermotogales optimal growth temperatures is best fit by a biased random walk model. These findings suggest that it may be easier to evolve from a high optimal growth temperature to a lower one than vice versa. PMID:23966548

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

    PubMed Central

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

    2015-01-01

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

  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

    2006-12-31

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

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

    EPA Science Inventory

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

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

    PubMed Central

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

    2015-01-01

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

  13. Do homologous thermophilic-mesophilic proteins exhibit similar structures and dynamics at optimal growth temperatures? A molecular dynamics simulation study.

    PubMed

    Basu, Sohini; Sen, Srikanta

    2013-02-25

    Structure and dynamics both are known to be important for the activity of a protein. A fundamental question is whether a thermophilic protein and its mesophilic homologue exhibit similar dynamics at their respective optimal growth temperatures. We have addressed this question by performing molecular dynamics (MD) simulations of a natural mesophilic-thermophilic homologue pair at their respective optimal growth temperatures to compare their structural, dynamical, and solvent properties. The MD simulations were done in explicit aqueous solvent under periodic boundary and constant pressure and temperature (CPT) conditions and continued for 10.0 ns using the same protocol for the two proteins, excepting the temperatures. The trajectories were analyzed to compare the properties of the two proteins. Results indicated that the dynamical behaviors of the two proteins at the respective optimal growth temperatures were remarkably similar. For the common residues in the thermophilic protein, the rms fluctuations have a general trend to be slightly higher compared to that in the mesophilic counterpart. Lindemann parameter values indicated that only a few residues exhibited solid-like dynamics while the protein as a whole appeared as a molten globule in each case. Interestingly, the water-water interaction was found to be strikingly similar in spite of the difference in temperatures while, the protein-water interaction was significantly different in the two simulations. PMID:23267663

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

    E-print Network

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

    2006-12-05

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

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

    ERIC Educational Resources Information Center

    Shin, Tacksoo

    2012-01-01

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

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

    USGS Publications Warehouse

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

    2006-01-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  18. OPTIMAL GEOMETRY IN EQUILIBRIUM AND GROWTH by Fred Almgren & Jean E. Taylor

    E-print Network

    Taylor, Jean

    natural processes involving surface free energy@math.rutgers.edu) ______________________________________________________________________________* *___ ABSTRACT We discuss geometric optimization as a mathematical device with which to model* * several formulate and solve proble* *ms for the nondifferentiable surface energies which lead to faceted crystals

  19. Reproducibility of Volumetric Computed Tomography of Stable Small Pulmonary Nodules with Implications on Estimated Growth Rate and Optimal Scan Interval

    PubMed Central

    Smith, Gary T.; Rahman, Ahmad R.; Li, Ming; Moore, Brandon; Gietema, Hester; Veronesi, Giulia; Massion, Pierre P.; Walker, Ronald C.

    2015-01-01

    Purpose To use clinically measured reproducibility of volumetric CT (vCT) of lung nodules to estimate error in nodule growth rate in order to determine optimal scan interval for patient follow-up. Methods We performed quantitative vCT on 89 stable non-calcified nodules and 49 calcified nodules measuring 3–13 mm diameter in 71 patients who underwent 3–9 repeat vCT studies for clinical evaluation of pulmonary nodules. Calculated volume standard deviation as a function of mean nodule volume was used to compute error in estimated growth rate. This error was then used to determine the optimal patient follow-up scan interval while fixing the false positive rate at 5%. Results Linear regression of nodule volume standard deviation versus the mean nodule volume for stable non-calcified nodules yielded a slope of 0.057±0.002 (r2 = 0.79, p<0.001). For calcified stable nodules, the regression slope was 0.052±0.005 (r2 = 0.65, p = 0.03). Using this with the error propagation formula, the optimal patient follow-up scan interval was calculated to be 81 days, independent of initial nodule volume. Conclusions Reproducibility of vCT is excellent, and the standard error is proportional to the mean calculated nodule volume for the range of nodules examined. This relationship constrains statistical certainty of vCT calculated doubling times and results in an optimal scan interval that is independent of the initial nodule volume. PMID:26379272

  20. Optimation growth of platinum and palladium nanoparticles on stainless steel 316L and activated carbon pellet substrates

    NASA Astrophysics Data System (ADS)

    Iwantono, Taer, E.; Umar, A. A.

    2012-06-01

    In this study, an optimation growth of platinum (PtNs) and palladium (PdNs) nanoparticles has successfully grown on stainless steel 316L and activated carbon pellet as substrates. PtNs and PdNs were grown on the substrates by wet chemical method. The effect of concentration of ascorbic acid and multi-growth step had shown the significantly in density and particle size distribution on the both substrates. The morphology and the structure of PtNs and PdNs were characterized by a field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), respectively. Homogenous particles size and high density of PtNs and PdNs on the substrates were also successfully grown with current method.

  1. Optimism

    PubMed Central

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

    2010-01-01

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

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

    E-print Network

    Palmer, Michael W.

    how mode of application of known PGPB affects plant growth, and second to evaluate the effect preliminary surface sterilization of seeds (a common practice in phytoremediation trials) followed plant species, Atriplex lentiformis and Buchloe dactyloides, suggest that seed surface sterilization

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

    E-print Network

    Steiner, Stephen Alan, III

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Pandit, Abhay Smashikant

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

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

    PubMed Central

    Lee, Meonghun; Yoe, Hyun

    2015-01-01

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

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

    PubMed

    Lee, Meonghun; Yoe, Hyun

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Gao, B.; Kakimoto, K.

    2014-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2015-12-01

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

  11. Optimization of flow assisted entrapment of pollen grains in a microfluidic platform for tip growth analysis.

    PubMed

    Sanati Nezhad, Amir; Ghanbari, Mahmood; Agudelo, Carlos G; Naghavi, Mahsa; Packirisamy, Muthukumaran; Bhat, Rama B; Geitmann, Anja

    2014-02-01

    A biocompatible polydimethylsiloxane (PDMS) biomicrofluidic platform is designed, fabricated and tested to study protuberance growth of single plant cells in a micro-vitro environment. The design consists of an inlet to introduce the cell suspension into the chip, three outlets to conduct the medium or cells out of the chip, a main distribution chamber and eight microchannels connected to the main chamber to guide the growth of tip growing plant cells. The test cells used here were pollen grains which produce cylindrical protrusions called pollen tubes. The goal was to adjust the design of the microfluidic network with the aim to enhance the uniformly distributed positioning of pollen grains at the entrances of the microchannels and to provide identical fluid flow conditions for growing pollen tubes along each microchannel. Computational fluid analysis and experimental testing were carried out to estimate the trapping efficiencies of the different designs. PMID:24013680

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

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

  14. Growth optimization and optical properties of AlGaNAs alloys

    SciTech Connect

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

    2014-04-28

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

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

    SciTech Connect

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    SciTech Connect

    Emanuela Barzi; Sara Mattafirri

    2002-10-25

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

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

    PubMed

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Shibuya, Keisuke; Sawa, Akihito

    2015-10-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

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

    PubMed Central

    Sicher, Richard C.

    2015-01-01

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

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

    PubMed

    Sicher, Richard C

    2015-01-01

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

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

    ERIC Educational Resources Information Center

    Benson, James G.; Borman, Geoffrey D.

    2007-01-01

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

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

    ERIC Educational Resources Information Center

    Brooks, Morris, Jr.

    2009-01-01

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

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

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

    PubMed Central

    Merchant, Sabeeha S.; Helmann, John D.

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

    Nitric oxide (NO) has many biological roles (e.g., antimicrobial agent, promoter of angiogenesis, prevention of platelet activation, etc.) 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 ± 0.7 wt %) and Tecophillic SP-60D-20 (22.5 ± 1.1 wt%)) were doped with 25 wt% DBHD/N2O2 and 10 wt% 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 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 24 h (~4 log reduction). The NO release patches are also able to reduce the TGF-? levels, in comparison to controls, which can enhance reepithelialization, 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

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

    PubMed

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

    2012-02-14

    Novel ?–conjugated cyanostilbene-based semiconductors (Hex-3,5-TFPTA and Hex-4-TFPTA) with tight molecular stacking and optimized energy levels are synthesized. Hex-4-TFPTA exhibits high-performance n-type organic field-effect transistor (OFET) properties with electron mobilities as high as 2.14 cm2 V?1s?1 and on-off current ratios PMID:22403831

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

    SciTech Connect

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

    2012-01-16

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

  12. Unmet Promise: Raising Minority Achievement. The Achievement Gap.

    ERIC Educational Resources Information Center

    Johnston, Robert C.; Viadero, Debra

    2000-01-01

    This first in a four-part series on why academic achievement gaps persist discusses how to raise minority achievement. It explains how earlier progress in closing the gap has stalled, while at the same time, the greater diversity of student populations and the rapid growth of the Hispanic population and of other ethnic groups have reshaped the…

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

    PubMed Central

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

    2014-01-01

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

  14. Nutrient improvement using statistical optimization for growth of Schizophyllum commune, and its antifungal activity against wood degrading fungi of rubberwood.

    PubMed

    Teoh, Yi Peng; Don, Mashitah Mat; Ujang, Salmiah

    2012-01-01

    Two statistical tools, Plackett-Burman design (PBD) and Box-Behnken design (BBD) were used to optimize the mycelia growth of Schizophyllum commune with different nutrient components. Results showed that 32.92 g/L of biomass were produced using a medium consisting of 18.74 g/L yeast extract, 38.65 g/L glucose, and 0.59 g/L MgSO(4).7H(2)O. The experimental data fitted well with the model predicted values within 0.09 to 0.77% error. The biomass was also tested for antifungal activity against wood degrading fungi of rubberwood. Results showed that the minimum inhibitory concentration (MIC) values for antifungal activity range from 0.16 to 5.00 ?g/?L. The GC-MS analysis indicated that this fungus produced several compounds, such as glycerin, 2(3H)-furanone, 5-heptyldihydro-, 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, and triacetin. PMID:21990033

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

    PubMed

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

    2012-04-01

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

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

    SciTech Connect

    Srinivasan, Kumar; Piramanayagam, S. N.

    2008-01-15

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

  17. Sharing Leadership Responsibilities Results in Achievement Gains

    ERIC Educational Resources Information Center

    Armistead, Lew

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Schaefer, Brian; Grant, Daniel; Biswas, Amlan

    2014-03-01

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

  19. The Lindahl equilibrium in Schumpeterian growth models: Knowledge diffusion, social value of innovations and optimal R&D

    E-print Network

    of prices that sustains the first-best social optimum in an economy with non rival goods, appears in a standard endogenous growth model with vertical innovations that explicitly exhibits knowledge diffusion". The standard literature on growth with vertical innovations generally focuses on a decentralized economy

  20. Investigation of Optimal Parameters for Oxide-Assisted Growth of Vertically Aligned Single-Walled Carbon Nanotubes

    E-print Network

    Wikswo, John

    and Technology, Rice UniVersity, Houston, Texas 77005, Department of Physics, Cornell UniVersity, Ithaca, New having the most dominant effect upon carpet growth. Utilizing water-assisted growth, this process supercapacitors,4,5 chemical sensors,6,7 self- cleaning adhesive tapes,8,9 and filtration membranes.10,11 How

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

    SciTech Connect

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

    2014-01-28

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

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

    E-print Network

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

    2010-01-01

    Background and Aims: Prediction of phenotypic traits from new genotypes under untested environmental conditions is crucial to build simulations of breeding strategies to improve target traits. Although the plant response to environmental stresses is characterized by both architectural and functional plasticity, recent attempts to integrate biological knowledge into genetics models have mainly concerned specific physiological processes or crop models without architecture, and thus may prove limited when studying genotype x environment interactions. Consequently, this paper presents a simulation study introducing genetics into a functional-structural growth model, which gives access to more fundamental traits for quantitative trait loci (QTL) detection and thus to promising tools for yield optimization. Methods: The GreenLab model was selected as a reasonable choice to link growth model parameters to QTL. Virtual genes and virtual chromosomes were defined to build a simple genetic model that drove the settings ...

  3. Self-Beliefs and Student Goal Achievement

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    SciTech Connect

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

    2013-08-05

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

  5. Achieving business growth through minority equity partnerships.

    PubMed

    Pavia, L

    1998-10-01

    Healthcare organizations can become more accessible to patients and managed care organizations and can expand their patient base by forming minority equity partnerships with physician practices. By investing in practices, healthcare organizations provide capital and guidance to help the practices grow. Such an arrangement fosters goodwill as the physicians retain ownership interests, which preserves their entrepreneurial spirit. PMID:10187621

  6. Trade-offs between drug toxicity and benefit in the multi-antibiotic resistance system underlie optimal growth of E. coli

    PubMed Central

    2012-01-01

    Background Efflux is a widespread mechanism of reversible drug resistance in bacteria that can be triggered by environmental stressors, including many classes of drugs. While such chemicals when used alone are typically toxic to the cell, they can also induce the efflux of a broad range of agents and may therefore prove beneficial to cells in the presence of multiple stressors. The cellular response to a combination of such chemical stressors may be governed by a trade-off between the fitness costs due to drug toxicity and benefits mediated by inducible systems. Unfortunately, disentangling the cost-benefit interplay using measurements of bacterial growth in response to the competing effects of the drugs is not possible without the support of a theoretical framework. Results Here, we use the well-studied multiple antibiotic resistance (MAR) system in E. coli to experimentally characterize the trade-off between drug toxicity (“cost”) and drug-induced resistance (“benefit”) mediated by efflux pumps. Specifically, we show that the combined effects of a MAR-inducing drug and an antibiotic are governed by a superposition of cost and benefit functions that govern these trade-offs. We find that this superposition holds for all drug concentrations, and it therefore allows us to describe the full dose–response diagram for a drug pair using simpler cost and benefit functions. Moreover, this framework predicts the existence of optimal growth at a non-trivial concentration of inducer. We demonstrate that optimal growth does not coincide with maximum induction of the mar promoter, but instead results from the interplay between drug toxicity and mar induction. Finally, we derived and experimentally validated a general phase diagram highlighting the role of these opposing effects in shaping the interaction between two drugs. Conclusions Our analysis provides a quantitative description of the MAR system and highlights the trade-off between inducible resistance and the toxicity of the inducing agent in a multi-component environment. The results provide a predictive framework for the combined effects of drug toxicity and induction of the MAR system that are usually masked by bulk measurements of bacterial growth. The framework may also be useful for identifying optimal growth conditions in more general systems where combinations of environmental cues contribute to both transient resistance and toxicity. PMID:22631053

  7. Bridgman crystal growth

    NASA Technical Reports Server (NTRS)

    Carlson, Frederick

    1990-01-01

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

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

    PubMed

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

    2015-12-01

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

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

    PubMed Central

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

    2015-01-01

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

  10. Graded Achievement, Tested Achievement, and Validity

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Twenty-eight studies of grades, over a century, were reviewed using the argument-based approach to validity suggested by Kane as a theoretical framework. The review draws conclusions about the meaning of graded achievement, its relation to tested achievement, and changes in the construct of graded achievement over time. "Graded…

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

    USGS Publications Warehouse

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

    2011-01-01

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

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

    PubMed Central

    Rothstein, Steven J.

    2014-01-01

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

  13. Optimization of growth methods and recombinant protein production in BTI-Tn-5B1-4 insect cells using the baculovirus expression system.

    PubMed

    Wickham, T J; Nemerow, G R

    1993-01-01

    A novel insect cell line from Trichoplusia ni, BTI-Tn 5B1-4 (Tn 5), was compared to Spodoptera frugiperda, Sf 9, cells for production of two recombinant secreted proteins: truncated Epstein-Barr viral attachment protein (EBV gp105) and truncated, soluble tissue factor (sTF). Under optimum conditions for both cell lines, Tn 5 cells produced 28-fold more secreted sTF than Sf 9 cells, respectively, on a per cell basis. The total production of gp105 was similar for the two cell lines. However, Tn5 cells secreted gp105 much more efficiently, resulting in 5-fold higher levels in the extracellular medium. Despite these increases, Tn 5 cells are attachment-dependent, and protein production is sensitive to the cell density (cells/cm2), unlike the Sf9 cell line which can be easily grown and scaled up in cell suspension cultures without significantly affecting its per cell production. Thus, protein production from Tn 5 cells above 0.1 L scales was optimized with respect to cell density using standard techniques for the growth of attachment-dependent cells. Roller bottles precoated with DEAE-based microcarriers and suspension cultures employing collagen-coated microcarriers were found to be effective ways of culturing Tn 5 cells. Predetermined optimal cell densities were used to produce EBV gp105 in microcarrier-coated roller bottles or in suspension cultures using collagen-coated microcarriers at concentrations close to those observed in tissue culture flasks. PMID:7764044

  14. The growth and optimization of InPSb/InGaAs/InAsSb strained-layer superlattice emitters by metal organic chemical vapor deposition

    SciTech Connect

    Biefeld, R.M.; Kurtz, S.R.

    1995-05-01

    The authors have prepared InAsSb/InGaAs strained-layer superlattices (SLS`s) and lnPSb confinement layers using metal-organic chemical vapor deposition (MOCVD) for use as infrared emitters. X-ray diffraction was used to determine lattice matching as well as composition and structure of the SLS`s. Photoluminescence linewidth and intensity were used as a measure of the quality of the structures. Typical FWHM were less than 10 meV. The presence of interface layers were indicated by broadened X-ray diffraction peaks for samples grown under non-optimized conditions. Two types of interfacial layers apparently due to a difference in composition at the interfaces were observed with transmission electron microscopy (TEM). The width of the X-ray peaks can be explained by a variation of the interfacial layer thicknesses. Optimized growth resulted in SLS`s with narrow X-ray peaks and high radiative efficiency. Room temperature LEDs operating between 4-5 {mu}m have been prepared.

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

    PubMed Central

    Babi?, Janja; Likozar, Blaž; Pavko, Aleksander

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Jagtap, Piyush; Kumar, Praveen

    2015-04-01

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

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

    PubMed

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

    2009-06-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Himeoka, Yusuke; Kaneko, Kunihiko

    2014-10-01

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

  20. Fibroblast Growth Factor (FGF) Receptor/FGF Inhibitors: Novel Targets and Strategies for Optimization of Response of Solid Tumors.

    PubMed

    Hierro, Cinta; Rodon, Jordi; Tabernero, Josep

    2015-12-01

    The fibroblast growth factor receptor (FGFR) pathway plays a major role in several biological processes, from organogenesis to metabolism homeostasis and angiogenesis. Several aberrations, including gene amplifications, point mutations, and chromosomal translocations have been described across solid tumors. Most of these molecular alterations promote multiple steps of carcinogenesis in FGFR oncogene-addicted cells, increasing cell proliferation, angiogenesis, and drug resistance. Data suggest that upregulation of FGFR signaling is a common event in many cancer types. The FGFR pathway thus arises as a potential promising target for cancer treatment. Several FGFR inhibitors are currently under development. Initial preclinical results have translated into limited successful clinical responses when first-generation, nonspecific FGFR inhibitors were evaluated in patients. The future development of selective and unselective FGFR inhibitors will rely on a better understanding of the tissue-specific role of FGFR signaling and identification of biomarkers to select those patients who will benefit the most from these drugs. Further studies are warranted to establish the predictive significance of the different FGFR-aberrations and to incorporate them into clinical algorithms, now that second-generation, selective FGFR inhibitors exist. PMID:26615127

  1. miR-17-92 fine-tunes MYC expression and function to ensure optimal B cell lymphoma growth

    PubMed Central

    Mihailovich, Marija; Bremang, Michael; Spadotto, Valeria; Musiani, Daniele; Vitale, Elena; Varano, Gabriele; Zambelli, Federico; Mancuso, Francesco M.; Cairns, David A.; Pavesi, Giulio; Casola, Stefano; Bonaldi, Tiziana

    2015-01-01

    The synergism between c-MYC and miR-17-19b, a truncated version of the miR-17-92 cluster, is well-documented during tumor initiation. However, little is known about miR-17-19b function in established cancers. Here we investigate the role of miR-17-19b in c-MYC-driven lymphomas by integrating SILAC-based quantitative proteomics, transcriptomics and 3? untranslated region (UTR) analysis upon miR-17-19b overexpression. We identify over one hundred miR-17-19b targets, of which 40% are co-regulated by c-MYC. Downregulation of a new miR-17/20 target, checkpoint kinase 2 (Chek2), increases the recruitment of HuR to c-MYC transcripts, resulting in the inhibition of c-MYC translation and thus interfering with in vivo tumor growth. Hence, in established lymphomas, miR-17-19b fine-tunes c-MYC activity through a tight control of its function and expression, ultimately ensuring cancer cell homeostasis. Our data highlight the plasticity of miRNA function, reflecting changes in the mRNA landscape and 3? UTR shortening at different stages of tumorigenesis. PMID:26555894

  2. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Meyyappan, M.

    2004-01-01

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

  3. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  4. Optimal control of plates using incompatible strains

    NASA Astrophysics Data System (ADS)

    Jones, G. W.; Mahadevan, L.

    2015-09-01

    A flat plate will bend into a curved shell if it experiences an inhomogeneous growth field or if constrained appropriately at a boundary. While the forward problem associated with this process is well studied, the inverse problem of designing the boundary conditions or growth fields to achieve a particular shape is much less understood. We use ideas from variational optimization theory to formulate a well posed version of this inverse problem to determine the optimal growth field or boundary condition that will give rise to an arbitrary target shape, optimizing for both closeness to the target shape and for smoothness of the growth field. We solve the resulting system of PDE numerically using finite element methods with examples for both the fully non-symmetric case as well as for simplified one-dimensional and axisymmetric geometries. We also show that the system can also be solved semi-analytically by positing an ansatz for the deformation and growth fields in a circular disk with given thickness profile, leading to paraboloidal, cylindrical and saddle-shaped target shapes, and show how a soft mode can arise from a non-axisymmetric deformation of a structure with axisymmetric material properties.

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  6. Which Achievement Gap?

    ERIC Educational Resources Information Center

    Anderson, Sharon; Medrich, Elliott; Fowler, Donna

    2007-01-01

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

  7. Affecting Achievement Motivation.

    ERIC Educational Resources Information Center

    Parker, Jane E.; Johnson, Candine E.

    While children approach performance situations with different combinations of motives, parenting and teaching practices can influence the development of each child's achievement behavior. Because achievement motivation is learned, and its development begins early in life with a critical stage during early childhood, it is necessary that pertinent…

  8. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

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

  9. Aboriginal Student Achievement Program

    E-print Network

    Saskatchewan, University of

    Aboriginal Student Achievement Program (ASAP) For more information, contact: Program Information@arts.usask.ca artsandscience.usask.ca/students/aboriginal/asap.php "I really want to connect with other aboriginal students · LiaisonwithFirstNationsbands The Aboriginal Student Achievement Program (ASAP) Morethan800

  10. General Achievement Trends: Massachusetts

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  11. General Achievement Trends: Idaho

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  12. General Achievement Trends: Nebraska

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  13. General Achievement Trends: Oklahoma

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  14. General Achievement Trends: Hawaii

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  15. General Achievement Trends: Iowa

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  16. General Achievement Trends: Arkansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  17. General Achievement Trends: Texas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  18. General Achievement Trends: Alabama

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  19. General Achievement Trends: Virginia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  20. General Achievement Trends: Florida

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  1. General Achievement Trends: Georgia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  2. General Achievement Trends: Michigan

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  3. General Achievement Trends: Kentucky

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  4. General Achievement Trends: Colorado

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  5. General Achievement Trends: Maine

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  6. General Achievement Trends: Maryland

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  7. General Achievement Trends: Oregon

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  8. General Achievement Trends: Tennessee

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  9. General Achievement Trends: Kansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

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

    E-print Network

    Peng, Huei

    Journal of Power Sources, Vol.165, issue 2, March 2007, pp.819-832. 1 Abstract-- Power management Management and Design Optimization of Fuel Cell/Battery Hybrid Vehicles #12;Journal of Power Sources, Vol.165 vehicles because of the multiple power sources and differences in their characteristics. Furthermore

  11. [Achievement of therapeutic objectives].

    PubMed

    Mantilla, Teresa

    2014-07-01

    Therapeutic objectives for patients with atherogenic dyslipidemia are achieved by improving patient compliance and adherence. Clinical practice guidelines address the importance of treatment compliance for achieving objectives. The combination of a fixed dose of pravastatin and fenofibrate increases the adherence by simplifying the drug regimen and reducing the number of daily doses. The good tolerance, the cost of the combination and the possibility of adjusting the administration to the patient's lifestyle helps achieve the objectives for these patients with high cardiovascular risk. PMID:25043543

  12. Achievement goals and emotions.

    PubMed

    Puente-Díaz, Rogelio

    2013-01-01

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

  13. POLICIES FOR ACHIEVING ENERGY

    E-print Network

    Delaware, University of

    POLICIES FOR ACHIEVING ENERGY JUSTICE IN SOCIETY: BEST PRACTICES FOR APPLYING SOLAR ENERGY FOR APPLYING SOLAR ENERGY TECHNOLOGIES TO LOW-INCOME HOUSING Final Report A Renewable Energy Applications.0 State Solar Energy Assistance Programs................................................. 21 5.1 Case

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    McCabe, Molly

    2010-01-01

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

  17. Prospective Optimization

    PubMed Central

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

    2014-01-01

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

  18. Bilingualism and Academic Achievement

    ERIC Educational Resources Information Center

    Han, Wen-Jui

    2012-01-01

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

  19. Polyethylene fiber drawing optimization

    E-print Network

    Chiloyan, Vazrik

    2011-01-01

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

  20. Intelligence and Educational Achievement

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  1. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

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

  2. Explorations in achievement motivation

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.

    1982-01-01

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

  3. Achieving Peace through Education.

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

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

  4. School Students' Science Achievement

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  5. Academic Achievement and Nongradedness

    ERIC Educational Resources Information Center

    Engel, Barney M.; Cooper, Martin

    1971-01-01

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

  6. Essays on Educational Achievement

    ERIC Educational Resources Information Center

    Ampaabeng, Samuel Kofi

    2013-01-01

    This dissertation examines the determinants of student outcomes--achievement, attainment, occupational choices and earnings--in three different contexts. The first two chapters focus on Ghana while the final chapter focuses on the US state of Massachusetts. In the first chapter, I exploit the incidence of famine and malnutrition that resulted to…

  7. INTELLIGENCE, PERSONALITY AND ACHIEVEMENT.

    ERIC Educational Resources Information Center

    MUIR, R.C.; AND OTHERS

    A LONGITUDINAL DEVELOPMENTAL STUDY OF A GROUP OF MIDDLE CLASS CHILDREN IS DESCRIBED, WITH EMPHASIS ON A SEGMENT OF THE RESEARCH INVESTIGATING THE RELATIONSHIP OF ACHIEVEMENT, INTELLIGENCE, AND EMOTIONAL DISTURBANCE. THE SUBJECTS WERE 105 CHILDREN AGED FIVE TO 6.3 ATTENDING TWO SCHOOLS IN MONTREAL. EACH CHILD WAS ASSESSED IN THE AREAS OF…

  8. SALT and Spelling Achievement.

    ERIC Educational Resources Information Center

    Nelson, Joan

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

  9. The Latino Achievement Gap

    ERIC Educational Resources Information Center

    Madrid, E. Michael

    2011-01-01

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

  10. Advancing Student Achievement

    ERIC Educational Resources Information Center

    Walberg, Herbert J.

    2010-01-01

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

  11. Optimization of air-assisted CVD growth of vertically-aligned ZnO nanowires, guided by structural analysis using X-ray scattering

    NASA Astrophysics Data System (ADS)

    Ok, Jong G.; Hart, A. John

    2009-03-01

    ZnO nanowires (ZNWs) are of significant interest for applications ranging from optical sensors to vibrational energy harvesters, due to properties including UV photoluminescence and piezoelectricity. We have studied low-pressure growth of ZNWs using a vapor transport method in air flowing within a tube furnace, giving vertically-aligned ZNW arrays on sapphire substrates seeded by Au catalysts. The growth rate and the average length of ZNWs depend on the flow rate of air and the total growth time, while multiple parameters such as catalyst thickness, pressure, and temperature also interdependently affect the ZNW characteristics. Grazing incidence small-angle X-ray scattering (GI-SAXS) measurements enable non-destructive quantification of ZNW diameter and alignment. By fitting GI-SAXS images using analytical models of the array as a population of solid cylinders having a Gaussian diameter distribution, we establish precise relationships between the structural characteristics and the growth conditions; for example, we determine rates of radial growth and size distribution broadening in comparison to axial growth. Control of the temperature gradient within the furnace also enables growth of well-aligned arrays at substrate temperatures as low as 600 ^oC.

  12. Growth rates of the population in a branching Brownian motion with an inhomogeneous breeding potential

    E-print Network

    Berestycki, Julien; Harris, John W; Harris, Simon C; Roberts, Matthew I

    2012-01-01

    We consider a branching particle system where each particle moves as an independent Brownian motion and breeds at a rate proportional to its distance from the origin raised to the power $p$, for $p\\in[0,2)$. The asymptotic behaviour of the right-most particle for this system is already known; in this article we give large deviations probabilities for particles following "difficult" paths, growth rates along "easy" paths, the total population growth rate, and we derive the optimal paths which particles must follow to achieve this growth rate.

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

    PubMed

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

    2013-11-01

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

  14. Autoimmune control of lesion growth in CNS with minimal damage

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    Lesions in central nervous system (CNS) and their growth leads to debilitating diseases like Multiple Sclerosis (MS), Alzheimer's etc. We developed a model earlier [1, 2] which shows how the lesion growth can be arrested through a beneficial auto-immune mechanism. We compared some of the dynamical patterns in the model with different facets of MS. The success of the approach depends on a set of control parameters and their phase space was shown to have a smooth manifold separating the uncontrolled lesion growth region from the controlled. Here we show that an optimal set of parameter values exist in the model which minimizes system damage while, at once, achieving control of lesion growth.

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

    ERIC Educational Resources Information Center

    Huang, Chiungjung

    2011-01-01

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

  16. Achieving optimum filtration performance.

    PubMed

    Aurand, C; Jones, R

    2003-06-01

    Medical device and equipment manufacturers are faced with a plethora of choices in filter media. All filtration companies have specialists who are experienced in the correct selection of filter media and filter configuration to achieve the optimum filtration performance and results. Device and equipment manufacturers can find a true consultant who will be able to recommend the best material and configuration to do the job. PMID:12852117

  17. Growth hormone and growth?

    PubMed

    Harvey, Steve

    2013-09-01

    Pituitary GH is obligatory for normal growth in mammals, but the importance of pituitary GH in avian growth is less certain. In birds, pituitary GH is biologically active and has growth promoting actions in the tibia-test bioassay. Its importance in normal growth is indicated by the growth suppression following the surgical removal of the pituitary gland or after the immunoneutralization of endogenous pituitary GH. The partial restoration of growth in some studies with GH-treated hypophysectomized birds also suggests GH dependency in avian growth, as does the dwarfism that occurs in some strains with GHR dysfunctions. Circulating GH concentrations are also correlated with body weight gain, being high in young, rapidly growing birds and low in slower growing older birds. Nevertheless, despite these observations, there is an extensive literature that concludes pituitary GH is not important in avian growth. This is based on numerous studies with hypophysectomized and intact birds that show only slight, transitory or absent growth responses to exogenous GH-treatment. Moreover, while circulating GH levels correlate with weight gain in young birds, this may merely reflect changes in the control of pituitary GH secretion during aging, as numerous studies involving experimental alterations in growth rate fail to show positive correlations between plasma GH concentrations and the alterations in growth rate. Furthermore, growth is known to occur in the absence of pituitary GH, as most embryonic development occurs prior to the ontogenetic appearance of pituitary somatotrophs and the appearance of GH in embryonic circulation. Early embryonic growth is also independent of the endocrine actions of pituitary GH, since removal of the presumptive pituitary gland does not impair early growth. Embryonic growth does, however, occur in the presence of extrapituitary GH, which is produced by most tissues and has autocrine or paracrine roles that locally promote growth and development. The role of GH in avian growth is therefore still unclear. PMID:23376467

  18. Gear optimization

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  19. Optimal husbandry of hatchling Eastern Indigo Snakes (Drymarchon couperi) during a captive head-start program.

    PubMed

    Wines, Michael P; Johnson, Valerie M; Lock, Brad; Antonio, Fred; Godwin, James C; Rush, Elizabeth M; Guyer, Craig

    2015-01-01

    Optimal husbandry techniques are desirable for any headstart program, but frequently are unknown for rare species. Here we describe key reproductive variables and determine optimal incubation temperature and diet diversity for Eastern Indigo Snakes (Drymarchon couperi) grown in laboratory settings. Optimal incubation temperature was estimated from two variables dependent on temperature, shell dimpling, a surrogate for death from fungal infection, and deviation of an egg from an ovoid shape, a surrogate for death from developmental anomalies. Based on these relationships and size at hatching we determined optimal incubation temperature to be 26°C. Additionally, we used incubation data to assess the effect of temperature on duration of incubation and size of hatchlings. We also examined hatchling diets necessary to achieve optimal growth over a 21-month period. These snakes exhibited a positive linear relationship between total mass eaten and growth rate, when individuals were fed less than 1711?g of prey, and displayed constant growth for individuals exceeding 1711?g of prey. Similarly, growth rate increased linearly with increasing diet diversity up to a moderately diverse diet, followed by constant growth for higher levels of diet diversity. Of the two components of diet diversity, diet evenness played a stronger role than diet richness in explaining variance in hatchling growth. These patterns document that our goal of satiating snakes was achieved for some individuals but not others and that diets in which total grams consumed over the first 21 months of life is distributed equivalently among at least three prey genera yielded the fastest growth rates for hatchling snakes. PMID:25866094

  20. Observations on achieving total practice success.

    PubMed

    Berning, R K

    2000-04-01

    A doctor or group practice that understands the design of what the practice wants to be and develops a strategy to accomplish that end will invariably achieve a high level of performance. Performance areas in contemporary practice administration cover a wide area including growth, transition, and succession. Due to the wide and demanding areas in practice administration, it is important to address any practice planning effort in a comprehensive manner rather than a piecemeal approach. The foregoing will materially assist any practitioner to achieve the level of success they seek. PMID:11323928

  1. Achieving empowerment through information.

    PubMed

    Parmalee, J C; Scholomiti, T O; Whitman, P; Sees, M; Smith, D; Gardner, E; Bastian, C

    1993-05-01

    Despite the problems we encountered, which are not uncommon with the development and implementation of any data system, we are confident that our success in achieving our goals is due to the following: establishing a reliable information database connecting several related departments; interfacing with registration and billing systems to avoid duplication of data and chance for error; appointing a qualified Systems Manager devoted to the project; developing superusers to include intensive training in the operating system (UNIX), parameters of the information system, and the report writer. We achieved what we set out to accomplish: the development of a reliable database and reports on which to base a variety of hospital decisions; improved hospital utilization; reliable clinical data for reimbursement, quality management, and credentialing; enhanced communication and collaboration among departments; and an increased profile of the departments and staff. Data quality specialists, Utilization Management and Quality Management coordinators, and the Medical Staff Credentialing Supervisor and their managers are relied upon by physicians and administrators to provide timely information. The staff are recognized for their knowledge and expertise in their department-specific information. The most significant reward is the potential for innovation. Users are no longer restricted to narrow information corridors. UNIX programming encourages creativity without demanding a degree in computer science. The capability to reach and use diverse hospital database information is no longer a dream. PMID:10139109

  2. Students' Goal Achievement: Exploring Individual and Situational Factors

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  3. Bilingualism and academic achievement.

    PubMed

    Han, Wen-Jui

    2012-01-01

    Using the Early Childhood Longitudinal Study, Kindergarten Cohort, this study examines the role that bilingualism plays in children's academic developmental trajectories during their early school years, with particular attention on the school environment (N = 16,380). Growth-curve results showed that despite starting with lower math scores in kindergarten, Mixed Bilingual children fully closed the math gap with their White English Monolingual peers by fifth grade. However, because non-English-Dominant Bilinguals and non-English Monolinguals started kindergarten with significantly lower reading and math scores compared to their English Monolingual peers, by fifth grade the former groups still had significantly lower scores. School-level factors explained about one third of the reductions in the differences in children's academic performance. PMID:22098584

  4. Fully automated molecular biology routines on a plasmid-based functional proteomic workcell: Evaluation and Characterization of Yeast Strains Optimized for Growth on Xylose Expressing "Stealth" Insecticidal Peptides.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optimization of genes important to production of fuel ethanol from hemicellulosic biomass for use in developing improved commercial yeast strains is necessary to meet the rapidly expanding need for ethanol. The United States Department of Agriculture has developed a fully automated platform for mol...

  5. Use of growth hormone in children.

    PubMed

    Hindmarsh, Peter C; Dattani, Mehul T

    2006-05-01

    The introduction of recombinant DNA-derived human growth hormone (rhGH) in the mid-1980s allowed studies to be undertaken in a number of growth disorders other than the classic indication--growth-hormone deficiency (GHD). In patients with GHD, optimizing the dose and frequency of rhGH administration, and early instigation of therapy, has led to near-normalization of final height. The use of rhGH in the treatment of Turner syndrome, Prader-Willi syndrome, intrauterine growth restriction, and chronic renal failure demonstrated the efficacy of therapy, although the increase in final height (5-7 cm) is less than that achieved in GHD. Cost-benefit implications need to be considered in the next phases of evaluating the role of rhGH therapy in these indications. To date, rhGH has only received approval for the management of idiopathic short stature in the US; as with the other wider growth indications, the lack of formal randomized, controlled trials hampers the full evaluation of efficacy, and a cautious approach should, therefore, be adopted for this particular indication. rhGH has a good safety record, although there are current concerns about the possible long-term increased risk of colonic and lymphatic malignancy, which will require monitoring through national cancer registries. PMID:16932297

  6. Achieving closure at Fernald

    SciTech Connect

    Bradburne, John; Patton, Tisha C.

    2001-02-25

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

  7. Optimization of experimental and modelling parameters for the differentiation of beverage spoiling yeasts by Matrix-Assisted-Laser-Desorption/Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in response to varying growth conditions.

    PubMed

    Usbeck, Julia C; Kern, Carola C; Vogel, Rudi F; Behr, Jürgen

    2013-12-01

    The growth of spoiling yeasts in beverages results in reduced quality, economic and image losses. Therefore, biochemical and DNA-based identification methods have been developed but are mostly time-consuming and laborious. Matrix-Assisted-Laser-Desorption/Ionization-Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) could deliver discriminative peptide mass fingerprints within minutes and could thus be a rapid and reliable tool for identification and differentiation. However, routine analysis of yeasts by MALDI-TOF MS is yet impaired by low reproducibility and effects of different physiological states of organisms on the reliability of the identification method are still controversial. The aim of this study was to optimize sample preparation and measurement parameterization using three spoilage yeasts (Saccharomyces cerevisiae var. diastaticus, Wickerhamomyces anomalus and Debaryomyces hansenii). The influence of environmental or physiological parameters including oxygen availability, different nutrients, cell density and growth phase were analysed and revealed small differences in mass fingerprints. Yeasts grown in the presence or absence of oxygen were precisely differentiated along these differences in mass fingerprints and a crude classification of growth phase was possible. Cell concentration did not affect the spectra distinctly, neither qualitatively nor quantitatively, and an influence of available nutrients could not be measured in each case. However, core mass peaks remained constant under all tested conditions enabling reliable identification. PMID:24010620

  8. Light source performance achievements

    NASA Astrophysics Data System (ADS)

    Laclare, J. L.

    2001-07-01

    More and more third generation light sources (3GLS) have come into operation. All of them were successful in reaching their performances. Some of them, like the ESRF, achieved brilliances up to two orders of magnitude higher than their initial target. Experience with the operation of existing machines indicates some imperfections and possibilities for new projects to integrate possible corrections in their design. These include: operation at the diffraction limit with even higher brilliances, higher position stability, enhanced Touschek lifetimes with larger momentum acceptances combined with low chromaticity and feedback of coupled bunch transverse resistive wall instability, efficient control of the longitudinal coupled bunch instability, higher currents in single bunch, better signal to noise ratio by localising losses at selected places in the ring and avoiding the emission of high energy bremsstrahlung photons in the direction of beamlines, possibilities of permanent injection, production of focused photon beams, high quality insertion devices, etc. Over the last 5 years, intensive R&D was dedicated to linac driven SASE FELs. They are considered as genuine 4th generation light sources. Results are encouraging, but there is still a certain way to go before planning an X-ray FEL facility. Therefore, rings are likely to remain for a long time the sources of excellence for users.

  9. How fast-growing bacteria robustly tune their ribosome concentration to approximate growth-rate maximization

    PubMed Central

    Bosdriesz, Evert; Molenaar, Douwe; Teusink, Bas; Bruggeman, Frank J

    2015-01-01

    Maximization of growth rate is an important fitness strategy for bacteria. Bacteria can achieve this by expressing proteins at optimal concentrations, such that resources are not wasted. This is exemplified for Escherichia coli by the increase of its ribosomal protein-fraction with growth rate, which precisely matches the increased protein synthesis demand. These findings and others have led to the hypothesis that E. coli aims to maximize its growth rate in environments that support growth. However, what kind of regulatory strategy is required for a robust, optimal adjustment of the ribosome concentration to the prevailing condition is still an open question. In the present study, we analyze the ppGpp-controlled mechanism of ribosome expression used by E. coli and show that this mechanism maintains the ribosomes saturated with its substrates. In this manner, overexpression of the highly abundant ribosomal proteins is prevented, and limited resources can be redirected to the synthesis of other growth-promoting enzymes. It turns out that the kinetic conditions for robust, optimal protein-partitioning, which are required for growth rate maximization across conditions, can be achieved with basic biochemical interactions. We show that inactive ribosomes are the most suitable ‘signal’ for tracking the intracellular nutritional state and for adjusting gene expression accordingly, as small deviations from optimal ribosome concentration cause a huge fractional change in ribosome inactivity. We expect to find this control logic implemented across fast-growing microbial species because growth rate maximization is a common selective pressure, ribosomes are typically highly abundant and thus costly, and the required control can be implemented by a small, simple network. PMID:25754869

  10. Optimizing the water chemistry of the Novovoronezh NPP Units 3 and 4 to prevent growth of coolant pressure difference across the reactor

    NASA Astrophysics Data System (ADS)

    Kritskii, V. G.; Rodionov, Yu. A.; Berezina, I. G.; Zelenina, E. V.; Gavrilov, A. V.; Vitkovskii, S. L.; Shchedrin, M. G.; Galanin, A. V.; Gorburov, V. I.

    2014-02-01

    For a few fuel campaigns in the first years of their extended service life, the Novovoronezh NPP Units 3 and 4 had to operate with a limited reactor thermal power output due to constraints imposed on certain parameters of the reactor core. The decrease of thermal power output during a campaign was accompanied by a growth of pressure difference across the reactor caused by accumulation of deposits in the fuel assemblies, which in turn led to a growth in the number of leaky fuel rods. Compensating measures were implemented based on the results obtained from the performed investigations and modeling of corrosion product mass transfer processes, which in the final analysis made it possible to minimize the accumulation of deposits in fuel assemblies and loss of fuel rod tightness, and to exclude the need to limit the reactor thermal power as demanded by constraints imposed on the reactor core parameters.

  11. HEPEX - achievements and challenges!

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  12. Factors Influencing Seminar Learning and Academic Achievement.

    PubMed

    Spruijt, Annemarie; Leppink, Jimmie; Wolfhagen, Ineke; Bok, Harold; Mainhard, Tim; Scherpbier, Albert; van Beukelen, Peter; Jaarsma, Debbie

    2015-01-01

    Many veterinary curricula use seminars, interactive educational group formats in which some 25 students discuss questions and issues relating to course themes. To get indications on how to optimize the seminar learning process for students, we aimed to investigate relationships between factors that seem to be important for the seminar learning process, and to determine how these seminar factors account for differences in students' achievement scores. A 57-item seminar evaluation (USEME) questionnaire was administered to students right after they attended a seminar. In total, 80 seminars distributed over years 1, 2, and 3 of an undergraduate veterinary medicine curriculum were sampled and 988 questionnaires were handed in. Principal factor analysis (PFA) was conducted on 410 questionnaires to examine which items could be grouped together as indicators of the same factor, and to determine correlations between the derived factors. Multilevel regression analysis was performed to explore the effects of these seminar factors and students' prior achievement scores on students' achievement scores. Within the questionnaire, four factors were identified that influence the seminar learning process: teacher performance, seminar content, student preparation, and opportunities for interaction within seminars. Strong correlations were found between teacher performance, seminar content, and group interaction. Prior achievement scores and, to a much lesser extent, the seminar factor group interaction appeared to account for differences in students' achievement scores. The factors resulting from the present study and their relation to the method of assessment should be examined further, for example, in an experimental setup. PMID:26075625

  13. High cell density production of Deinococcus radiodurans under optimized conditions.

    PubMed

    He, Yi

    2009-04-01

    Deinococcus radiodurans is a bacterium being investigated for mechanisms of extreme radiation resistance and for bioremediation of environmental radioactive waste sites. In both fundamental and applied research settings, methods for large-scale production of D. radiodurans are needed. In this study, a systematic investigation was carried out to optimize D. radiodurans production at the 20-L fermentor scale. In defined medium, the phosphate buffer typically used was found to be inhibitory to D. radiodurans growth, and caused cell aggregation. Substitution of HEPES and MOPS buffers for phosphate buffer improved D. radiodurans growth characteristics. Several antifoaming agents were investigated to support large-scale production with submerged aeration, and the defoamer KFO 673 was chosen based on its ability to prevent foaming without affecting D. radiodurans growth. The conventional undefined rich medium tryptone/glucose/yeast extract (TGY) maximally supported D. radiodurans growth to an OD(600) of 10. Using a 'design of experiments' approach, we found glucose, Mg and Mn to be critical in supporting high-density growth of D. radiodurans. The optimal pH and temperature for D. radiodurans growth in large-scale preparations were 7.0 and 37 degrees C, respectively. Growth was carried out in a 20-L fermentor using the newly developed media under the optimal conditions. With addition of 10 g/L glucose, 0.5 g/L MgSO(4) . 7H(2)O, 5 microM MnCl(2) into TGY media, an OD(600) of 40 was achieved. PMID:19137334

  14. Attitude Towards Physics and Additional Mathematics Achievement Towards Physics Achievement

    ERIC Educational Resources Information Center

    Veloo, Arsaythamby; Nor, Rahimah; Khalid, Rozalina

    2015-01-01

    The purpose of this research is to identify the difference in students' attitude towards Physics and Additional Mathematics achievement based on gender and relationship between attitudinal variables towards Physics and Additional Mathematics achievement with achievement in Physics. This research focused on six variables, which is attitude towards…

  15. The Impact of Reading Achievement on Overall Academic Achievement

    ERIC Educational Resources Information Center

    Churchwell, Dawn Earheart

    2009-01-01

    This study examined the relationship between reading achievement and achievement in other subject areas. The purpose of this study was to determine if there was a correlation between reading scores as measured by the Standardized Test for the Assessment of Reading (STAR) and academic achievement in language arts, math, science, and social studies…

  16. High Growth Rate Metal-Organic Molecular Beam Epitaxy for the Fabrication of GaAs Space Solar Cells

    NASA Technical Reports Server (NTRS)

    Freundlich, A.; Newman, F.; Monier, C.; Street, S.; Dargan, P.; Levy, M.

    2005-01-01

    In this work it is shown that high quality GaAs photovoltaic devices can be produced by Molecular Beam Epitaxy (MBE) with growth rates comparable to metal-organic chemical vapor deposition (MOCVD) through the subsitution of group III solid sources by metal-organic compounds. The influence the III/V flux-ratio and growth temperatures in maintaining a two dimensional layer by layer growth mode and achieving high growth rates with low residual background impurities is investigated. Finally subsequent to the study of the optimization of n- and p doping of such high growth rate epilayers, results from a preliminary attempt in the fabrication of GaAs photovoltaic devices such as tunnel diodes and solar cells using the proposed high growth rate approach are reported.

  17. Hybrid Swarm Intelligence Optimization Approach for Optimal Data Storage Position Identification in Wireless Sensor Networks

    PubMed Central

    Mohanasundaram, Ranganathan; Periasamy, Pappampalayam Sanmugam

    2015-01-01

    The current high profile debate with regard to data storage and its growth have become strategic task in the world of networking. It mainly depends on the sensor nodes called producers, base stations, and also the consumers (users and sensor nodes) to retrieve and use the data. The main concern dealt here is to find an optimal data storage position in wireless sensor networks. The works that have been carried out earlier did not utilize swarm intelligence based optimization approaches to find the optimal data storage positions. To achieve this goal, an efficient swam intelligence approach is used to choose suitable positions for a storage node. Thus, hybrid particle swarm optimization algorithm has been used to find the suitable positions for storage nodes while the total energy cost of data transmission is minimized. Clustering-based distributed data storage is utilized to solve clustering problem using fuzzy-C-means algorithm. This research work also considers the data rates and locations of multiple producers and consumers to find optimal data storage positions. The algorithm is implemented in a network simulator and the experimental results show that the proposed clustering and swarm intelligence based ODS strategy is more effective than the earlier approaches. PMID:25734182

  18. Achieving Developmental Synchrony in Young Children With Hearing Loss

    PubMed Central

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

    2009-01-01

    Children with hearing loss, with early and appropriate amplification and intervention, demonstrate gains in speech, language, and literacy skills. Despite these improvements many children continue to exhibit disturbances in cognitive, behavioral, and emotional control, self-regulation, and aspects of executive function. Given the complexity of developmental learning, educational settings should provide services that foster the growth of skills across multiple dimensions. Transdisciplinary intervention services that target the domains of language, communication, psychosocial functioning, motor, and cognitive development can promote academic and social success. Educational programs must provide children with access to the full range of basic skills necessary for academic and social achievement. In addition to an integrated curriculum that nurtures speech, language, and literacy development, innovations in the areas of auditory perception, social emotional learning, motor development, and vestibular function can enhance student outcomes. Through ongoing evaluation and modification, clearly articulated curricular approaches can serve as a model for early intervention and special education programs. The purpose of this article is to propose an intervention model that combines best practices from a variety of disciplines that affect developmental outcomes for young children with hearing loss, along with specific strategies and approaches that may help to promote optimal development across domains. Access to typically developing peers who model age-appropriate skills in language and behavior, small class sizes, a co-teaching model, and a social constructivist perspective of teaching and learning, are among the key elements of the model. PMID:20150187

  19. Growth Disorders

    MedlinePLUS

    ... their parents are. But some children have growth disorders. Growth disorders are problems that prevent children from developing normal ... growth can sometimes signal a gland problem or disease. The pituitary gland makes growth hormone, which stimulates ...

  20. Growth Hormone

    MedlinePLUS

    ... limited. Home Visit Global Sites Search Help? Growth Hormone Share this page: Was this page helpful? Also known as: GH; Human Growth Hormone; HGH; Somatotropin; Growth Hormone Stimulation Test; Growth Hormone ...

  1. Involvement of the CasK/R two-component system in optimal unsaturation of the Bacillus cereus fatty acids during low-temperature growth.

    PubMed

    Diomandé, Sara Esther; Nguyen-The, Christophe; Abee, Tjakko; Tempelaars, Marcel H; Broussolle, Véronique; Brillard, Julien

    2015-11-20

    Bacillus cereus sensu lato is composed of a set of ubiquitous strains including human pathogens that can survive a range of food processing conditions, grow in refrigerated food, and sometimes cause food poisoning. We previously identified the two-component system CasK/R that plays a key role in cold adaptation. To better understand the CasK/R-controlled mechanisms that support low-temperature adaptation, we performed a transcriptomic analysis on the ATCC 14579 strain and its isogenic ?casK/R mutant grown at 12°C. Several genes involved in fatty acid (FA) metabolism were downregulated in the mutant, including desA and desB encoding FA acyl-lipid desaturases that catalyze the formation of a double-bond on the FA chain in positions ?5 and ?10, respectively. A lower proportion of FAs presumably unsaturated by DesA was observed in the ?casK/R strain compared to the parental strain while no difference was found for FAs presumably unsaturated by DesB. Addition of phospholipids from egg yolk lecithin rich in unsaturated FAs, to growth medium, abolished the cold-growth impairment of ?casK/R suggesting that exogenous unsaturated FAs can support membrane-level modifications and thus compensate for the decreased production of these FAs in the B. cereus ?casK/R mutant during growth at low temperature. Our findings indicate that CasK/R is involved in the regulation of FA metabolism, and is necessary for cold adaptation of B. cereus unless an exogenous source of unsaturated FAs is available. PMID:25987542

  2. Doublon Growth in Solidification

    E-print Network

    Brian Utter; E. Bodenschatz

    2004-08-13

    We present experiments on the doublon growth morphology in directional solidification. Samples used are succinonitrile with small amounts of poly(ethylene oxide), acetone, or camphor as the solute. Doublons, or symmetry-broken dendrites, are generic diffusion-limited growth structures expected at large undercooling and low anisotropy. Low anisotropy growth is achieved by selecting a grain near the $\\{111\\}$ plane leading to either seaweed (dense branching morphology) or doublon growth depending on experimental parameters. We find selection of doublons to be strongly dependent on solute concentration and sample orientation. Doublons are selected at low concentrations (low solutal undercooling) in contrast to the prediction of doublons at large thermal undercooling in pure materials. Doublons also exhibit preferred growth directions and changing the orientation of a specific doublonic grain changes the character and stability of the doublons. We observe transitions between seaweed and doublon growth with changes in concentration and sample orientation.

  3. Akamai technologies : an analysis of product and platform growth strategies

    E-print Network

    Piper, Victor L. (Victor Lawrence)

    2013-01-01

    Akamai Technologies has achieved market leadership in content delivery and application acceleration services and is pursuing aggressive growth. Akamai has advised the market that growth to $5B by 2020 is achievable by ...

  4. Effect of lipids on insect cell growth and expression of recombinant proteins in serum-free medium.

    PubMed

    Gilbert, R S; Nagano, Y; Yokota, T; Hwan, S F; Fletcher, T; Lydersen, K

    1996-01-01

    The lipid emulsion components of a serum-free insect cell medium were varied and evaluated for effects on cell growth and recombinant protein expression. The growth of High-Five(TM) cells was significantly affected by polyol Pluronic F-68 and Tween-80, but not by lipids. Pluronic was essential for cell growth, while Tween-80 was required to achieve maximum cell densities. A dose response effect was observed for Tween-80 with optimal cell growth at a concentration of 25 mg/l. Cholesterol had a minor effect on cell growth, but was essential for the expression of recombinant proteins. The expression of ?-galactosidase (?-gal) was directly affected by cholesterol with optimal expression at a concentration of 5.4 mg/l. Vitamin E, important as an antioxidant to stabilize lipids, did not directly affect recombinant protein expression. Although lipids were not required for cell growth, the presence of lipids were required during the cell growth phase in order to achieve efficient infection with baculovirus. These studies help to define the important components, and range of concentrations, for lipid emulsions which can effectively replace serum in insect cell culture. PMID:22358931

  5. Role of the seeding promoter in MoS2 growth by chemical vapor deposition.

    PubMed

    Ling, Xi; Lee, Yi-Hsien; Lin, Yuxuan; Fang, Wenjing; Yu, Lili; Dresselhaus, Mildred S; Kong, Jing

    2014-02-12

    The thinnest semiconductor, molybdenum disulfide (MoS2) monolayer, exhibits promising prospects in the applications of optoelectronics and valleytronics. A uniform and highly crystalline MoS2 monolayer in a large area is highly desirable for both fundamental studies and substantial applications. Here, utilizing various aromatic molecules as seeding promoters, a large-area, highly crystalline, and uniform MoS2 monolayer was achieved with chemical vapor deposition (CVD) at a relatively low growth temperature (650 °C). The dependence of the growth results on the seed concentration and on the use of different seeding promoters is further investigated. It is also found that an optimized concentration of seed molecules is helpful for the nucleation of the MoS2. The newly identified seed molecules can be easily deposited on various substrates and allows the direct growth of monolayer MoS2 on Au, hexagonal boron nitride (h-BN), and graphene to achieve various hybrid structures. PMID:24475747

  6. Learning optimal embedded cascades.

    PubMed

    Saberian, Mohammad Javad; Vasconcelos, Nuno

    2012-10-01

    The problem of automatic and optimal design of embedded object detector cascades is considered. Two main challenges are identified: optimization of the cascade configuration and optimization of individual cascade stages, so as to achieve the best tradeoff between classification accuracy and speed, under a detection rate constraint. Two novel boosting algorithms are proposed to address these problems. The first, RCBoost, formulates boosting as a constrained optimization problem which is solved with a barrier penalty method. The constraint is the target detection rate, which is met at all iterations of the boosting process. This enables the design of embedded cascades of known configuration without extensive cross validation or heuristics. The second, ECBoost, searches over cascade configurations to achieve the optimal tradeoff between classification risk and speed. The two algorithms are combined into an overall boosting procedure, RCECBoost, which optimizes both the cascade configuration and its stages under a detection rate constraint, in a fully automated manner. Extensive experiments in face, car, pedestrian, and panda detection show that the resulting detectors achieve an accuracy versus speed tradeoff superior to those of previous methods. PMID:22213762

  7. Achievement as Resistance: The Development of a Critical Race Achievement Ideology among Black Achievers

    ERIC Educational Resources Information Center

    Carter, Dorinda J.

    2008-01-01

    In this article, Dorinda Carter examines the embodiment of a critical race achievement ideology in high-achieving black students. She conducted a yearlong qualitative investigation of the adaptive behaviors that nine high-achieving black students developed and employed to navigate the process of schooling at an upper-class, predominantly white,…

  8. Optimal Periodic Training Signal for Frequency Offset Estimation in Frequency Selective Fading

    E-print Network

    Minn, Hlaing

    signal statistics. The optimal training structure with optimal training signals achieves substantial periodic training sig- nal design for frequency offset estimation in frequency selective multipath Rayleigh, the optimal periodic training signal structure (the optimal location of identical training sub

  9. Linear growth and neurodevelopmental outcomes.

    PubMed

    Pfister, Katie M; Ramel, Sara E

    2014-06-01

    Despite advances in care, preterm infants exhibit disproportionate growth and neurodevelopmental delay attributable to both nutritional and nonnutritional factors. These infants have prolonged linear stunting and decreased fat-free mass compared with their term counterparts. These 2 metrics index organ growth and development (including the brain) and protein accretion. Protein, along with carbohydrates, fats, and zinc, plays key roles in brain development, and deficiencies can lead to linear growth failure, abnormalities in the growth hormone axis, and developmental delay. Optimization of nutrition, including protein intake, decreasing inflammatory episodes, and enhancing the growth hormone axis will likely improve long-term outcomes. PMID:24873834

  10. Mathematics Achievement in High- and Low-Achieving Secondary Schools

    ERIC Educational Resources Information Center

    Mohammadpour, Ebrahim; Shekarchizadeh, Ahmadreza

    2015-01-01

    This paper identifies the amount of variance in mathematics achievement in high- and low-achieving schools that can be explained by school-level factors, while controlling for student-level factors. The data were obtained from 2679 Iranian eighth graders who participated in the 2007 Trends in International Mathematics and Science Study. Of the…

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

    ERIC Educational Resources Information Center

    Gilmore, Beatrice

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

  12. Growth condition optimization and mobility enhancement through prolonging the GaN nuclei coalescence process of AlGaN/AlN/GaN structure

    NASA Astrophysics Data System (ADS)

    He, Xiao-Guang; Zhao, De-Gang; Jiang, De-Sheng; Zhu, Jian-Jun; Chen, Ping; Liu, Zong-Shun; Le, Ling-Cong; Yang, Jing; Li, Xiao-Jing; Zhang, Shu-Ming; Yang, Hui

    2015-09-01

    AlGaN/AlN/GaN structures are grown by metalorganic vapor phase epitaxy on sapphire substrates. Influences of AlN interlayer thickness, AlGaN barrier thickness, and Al composition on the two-dimensional electron gas (2DEG) performance are investigated. Lowering the V/III ratio and enhancing the reactor pressure at the initial stage of the high-temperature GaN layer growth will prolong the GaN nuclei coalescence process and effectively improve the crystalline quality and the interface morphology, diminishing the interface roughness scattering and improving 2DEG mobility. AlGaN/AlN/GaN structure with 2DEG sheet density of 1.19 × 1013 cm-2, electron mobility of 2101 cm2·V-1·s-1, and square resistance of 249 ? is obtained. Project support by the National Natural Science Foundation of China (Grant Nos. 61474110, 61377020, 61376089, 61223005, and 61176126), the National Science Fund for Distinguished Young Scholars, China (Grant No. 60925017), the One Hundred Person Project of the Chinese Academy of Sciences, and the Basic Research Project of Jiangsu Province, China (Grant No. BK20130362).

  13. Affective Processes and Academic Achievement.

    ERIC Educational Resources Information Center

    Feshbach, Norma Deitch; Feshbach, Seymour

    1987-01-01

    Data indicate that for girls, affective dispositional factors (empathy, depressive affectivity, aggression, and self-concept) are intimately linked to cognitive development and academic achievement. (PCB)

  14. Sequential growth and monitoring of a polypyrrole actuator system

    NASA Astrophysics Data System (ADS)

    Sarrazin, J. C.; Mascaro, Stephen A.

    2014-03-01

    Electroactive polymers (EAPs) have emerged as viable materials in sensing and actuating applications, but the capability to mimic the structure and function of natural muscle is increased due to their ability to permit additional, sequential synthesis steps between stages of actuation. Current work is improving upon the mechanical performance in terms of achievable stresses, strains, and strain rates, but issues still remain with actuator lifetime and adaptability. This work seeks to create a bioinspired polymer actuation system that can be monitored using state estimation and adjusted in vivo during operation. The novel, time-saving process of sequential growth was applied to polymer actuator systems for the initial growth, as well as additional growth steps after actuation cycles. Synthesis of conducting polymers on a helical metal electrode directs polymer shape change during actuation, assists in charge distribution along the polymer for actuation, and as is described in this work, constructs a constant working electrode/polymer connection during operation which allows sequential polymer growth based on a performance need. The polymer system is monitored by means of a reduced-order, state estimation model that works between growth and actuation cycles. In this case, actuator stress is improved between growth cycles. The ability for additional synthesis of the polymer actuator not only creates an actuator system that can be optimized based on demand, but creates a dynamic actuator system that more closely mimics natural muscle capability.

  15. Expert System Control of Plant Growth in an Enclosed Space

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  16. Role of nutrient supply on cell growth in bioreactor design for tissue engineering of hematopoietic cells.

    PubMed

    Pathi, Pragyansri; Ma, Teng; Locke, Bruce R

    2005-03-30

    In the present study, a dynamic mathematical model for the growth of granulocyte progenitor cells in the hematopoietic process is developed based on the principles of diffusion and chemical reaction. This model simulates granulocyte progenitor cell growth and oxygen consumption in a three-dimensional (3-D) perfusion bioreactor. Material balances on cells are coupled to the nutrient balances in 3-D matrices to determine the effects of transport limitations on cell growth. The method of volume averaging is used to formulate the material balances for the cells and the nutrients in the porous matrix containing the cells. All model parameters are obtained from the literature. The maximum cell volume fraction reached when oxygen is depleted in the cell layer at 15 days and is nearly 0.63, corresponding to a cell density of 2.25 x 10(8) cells/mL. The substrate inhibition kinetics for cell growth lead to complex effects with respect to the roles of oxygen concentration and supply by convection and diffusion on cell growth. Variation in the height of the liquid layer above the cell matrix where nutrient supply is introduced affected the relative and absolute amounts of oxygen supply by hydrodynamic flow and by diffusion across a gas permeable FEP membrane. Mass transfer restrictions of the FEP membrane are considerable, and the supply of oxygen by convection is essential to achieve higher levels of cell growth. A maximum growth rate occurs at a specific flow rate. For flow rates higher than this optimal, the high oxygen concentration led to growth inhibition and for lower flow rates growth limitations occur due to insufficient oxygen supply. Because of the nonlinear effects of the autocatalytic substrate inhibition growth kinetics coupled to the convective transport, the rate of growth at this optimal flow rate is higher than that in a corresponding well-mixed reactor where oxygen concentration is set at the maximum indicated by the inhibitory kinetics. PMID:15696509

  17. Growth Problems

    MedlinePLUS

    ... function and also play a role in growth. Hypothyroidism can cause slow growth because the thyroid gland ... to support normal growth. A major symptom of hypothyroidism is feeling tired or sluggish. A blood test ...

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

    PubMed

    Himeoka, Yusuke; Kaneko, Kunihiko

    2014-10-01

    Cells generally convert external nutrient resources to support metabolism and growth. Understanding the thermodynamic efficiency of this conversion is essential to determine the general characteristics of cellular growth. Using a simple protocell model with catalytic reaction dynamics to synthesize the necessary enzyme and membrane components from nutrients, the entropy production per unit-cell-volume growth is calculated analytically and numerically based on the rate equation for chemical kinetics and linear nonequilibrium thermodynamics. The minimal entropy production per unit-cell growth is found to be achieved at a nonzero nutrient uptake rate rather than at a quasistatic limit as in the standard Carnot engine. This difference appears because the equilibration mediated by the enzyme exists only within cells that grow through enzyme and membrane synthesis. Optimal nutrient uptake is also confirmed by protocell models with many chemical components synthesized through a catalytic reaction network. The possible relevance of the identified optimal uptake to optimal yield for cellular growth is also discussed. PMID:25375530

  19. Optimizing a Ratchet Gear

    E-print Network

    I. M. Sokolov

    2002-07-29

    The energetic efficiencies of rocked ratchets reported in the literature typically lie in the sub-percent range. We discuss the problem of optimization of the energetic efficiency of a ratchet, and show that considerably higher efficiencies can be achieved; however this assumes a fine-tuning of the parameters of the system. The domain of parameters corresponding to high efficiencies is typically narrow.

  20. Combined optimization model for sustainable energization strategy

    NASA Astrophysics Data System (ADS)

    Abtew, Mohammed Seid

    Access to energy is a foundation to establish a positive impact on multiple aspects of human development. Both developed and developing countries have a common concern of achieving a sustainable energy supply to fuel economic growth and improve the quality of life with minimal environmental impacts. The Least Developing Countries (LDCs), however, have different economic, social, and energy systems. Prevalence of power outage, lack of access to electricity, structural dissimilarity between rural and urban regions, and traditional fuel dominance for cooking and the resultant health and environmental hazards are some of the distinguishing characteristics of these nations. Most energy planning models have been designed for developed countries' socio-economic demographics and have missed the opportunity to address special features of the poor countries. An improved mixed-integer programming energy-source optimization model is developed to address limitations associated with using current energy optimization models for LDCs, tackle development of the sustainable energization strategies, and ensure diversification and risk management provisions in the selected energy mix. The Model predicted a shift from traditional fuels reliant and weather vulnerable energy source mix to a least cost and reliable modern clean energy sources portfolio, a climb on the energy ladder, and scored multifaceted economic, social, and environmental benefits. At the same time, it represented a transition strategy that evolves to increasingly cleaner energy technologies with growth as opposed to an expensive solution that leapfrogs immediately to the cleanest possible, overreaching technologies.

  1. Perils of Standardized Achievement Testing

    ERIC Educational Resources Information Center

    Haladyna, Thomas M.

    2006-01-01

    This article argues that the validity of standardized achievement test-score interpretation and use is problematic; consequently, confidence and trust in such test scores may often be unwarranted. The problem is particularly severe in high-stakes situations. This essay provides a context for understanding standardized achievement testing, then…

  2. Teaching the Low Level Achiever.

    ERIC Educational Resources Information Center

    Salomone, Ronald E., Ed.

    1986-01-01

    Intended for teachers of the English language arts, the articles in this issue offer suggestions and techniques for teaching the low level achiever. Titles and authors of the articles are as follows: (1) "A Point to Ponder" (Rachel Martin); (2) "Tracking: A Self-Fulfilling Prophecy of Failure for the Low Level Achiever" (James Christopher Davis);…

  3. Stress Correlates and Academic Achievement.

    ERIC Educational Resources Information Center

    Bentley, Donna Anderson; And Others

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

  4. Raising Boys' Achievement in Schools.

    ERIC Educational Resources Information Center

    Bleach, Kevan, Ed.

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

  5. General Achievement Trends: New Jersey

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  6. The Impact of Assessment for Learning: Benefits and Barriers to Student Achievement

    ERIC Educational Resources Information Center

    Collins, Natalie M.

    2012-01-01

    The purpose of this study was to compare growth in student achievement of students in a classroom where the assessment for learning process was either absent from or present in a teacher's practices, and to gather the teacher's and students' perceptions of the benefits and barriers related to growth in student achievement when the…

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

    ERIC Educational Resources Information Center

    Robinson, Keith; Mueller, Anna S.

    2014-01-01

    Using nationally representative data on 12,462 kindergarten children, this report examines the link between behavioral engagement and math achievement growth during kindergarten. Multilevel models show that students with higher individual engagement tend to experience larger math achievement growth over kindergarten, that classroom engagement…

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

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

    SciTech Connect

    Datta, Saurav; Biswas, Ajay; Bhaumik, Swapan; Majumdar, Gautam

    2011-01-17

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

  10. Trajectory optimization for domains with contacts using inverse dynamics

    E-print Network

    Todorov, Emanuel

    Trajectory optimization for domains with contacts using inverse dynamics Tom Erez and Emanuel the control that yields a trajectory of minimal total cost. Global methods of optimal control find an optimal of trajectory optimization -- by identifying only locally-optimal trajectories, these algo- rithms achieve

  11. Convex Functions Smooth Optimization Non-Smooth Optimization Stochastic Optimization Convex Optimization

    E-print Network

    Marlin, Benjamin

    Convex Functions Smooth Optimization Non-Smooth Optimization Stochastic Optimization Convex Optimization Mark Schmidt - CMPT 419/726 #12;Convex Functions Smooth Optimization Non-Smooth Optimization;Convex Functions Smooth Optimization Non-Smooth Optimization Stochastic Optimization Motivation: Why

  12. The Effect of Primary School Size on Academic Achievement

    ERIC Educational Resources Information Center

    Gershenson, Seth; Langbein, Laura

    2015-01-01

    Evidence on optimal school size is mixed. We estimate the effect of transitory changes in school size on the academic achievement of fourth-and fifth-grade students in North Carolina using student-level longitudinal administrative data. Estimates of value-added models that condition on school-specific linear time trends and a variety of…

  13. The Effects of Temperature and Nutritional Conditions on Mycelium Growth of Two Oyster Mushrooms (Pleurotus ostreatus and Pleurotus cystidiosus).

    PubMed

    Hoa, Ha Thi; Wang, Chun-Li

    2015-03-01

    The influences of temperature and nutritional conditions on the mycelium growth of oyster mushroom Pleurotus ostreatus (PO) and Pleurotus cystidiosus (PC) were investigated in laboratory experiment during the summer season of 2014. The results of the experiment indicated that potato dextrose agar (PDA) and yam dextrose agar (YDA) were the most suitable media for the mycelium growth of oyster mushroom PO while four media (PDA, YDA, sweet potato dextrose agar, and malt extract agar medium) were not significantly different in supporting mycelium growth of oyster mushroom PC. The optimal temperature for mycelium growth of both oyster mushroom species was obtained at 28?. Mycelium growth of oyster mushroom PO was improved by carbon sources such as glucose, molasses, and at 1~5% sucrose concentration, mycelium colony diameter of mushroom PO was achieved the highest value. Whereas glucose, dextrose, and sucrose as carbon sources gave the good mycelium growth of oyster mushroom PC, and at 1~3% sucrose concentration, mycelium colony diameter of PC was achieved the maximum value. Ammonium chloride concentrations at 0.03~0.09% and 0.03~0.05% also gave the greatest values in mycelium colony diameter of mushroom PO and PC. Brown rice was found to be the most favourable for mycelium growth of two oyster mushroom species. In addition, sugarcane residue, acasia sawdust and corn cob were selected as favourable lignocellulosic substrate sources for mycelium growth of both oyster mushrooms. PMID:25892910

  14. The Effects of Temperature and Nutritional Conditions on Mycelium Growth of Two Oyster Mushrooms (Pleurotus ostreatus and Pleurotus cystidiosus)

    PubMed Central

    Hoa, Ha Thi

    2015-01-01

    The influences of temperature and nutritional conditions on the mycelium growth of oyster mushroom Pleurotus ostreatus (PO) and Pleurotus cystidiosus (PC) were investigated in laboratory experiment during the summer season of 2014. The results of the experiment indicated that potato dextrose agar (PDA) and yam dextrose agar (YDA) were the most suitable media for the mycelium growth of oyster mushroom PO while four media (PDA, YDA, sweet potato dextrose agar, and malt extract agar medium) were not significantly different in supporting mycelium growth of oyster mushroom PC. The optimal temperature for mycelium growth of both oyster mushroom species was obtained at 28?. Mycelium growth of oyster mushroom PO was improved by carbon sources such as glucose, molasses, and at 1~5% sucrose concentration, mycelium colony diameter of mushroom PO was achieved the highest value. Whereas glucose, dextrose, and sucrose as carbon sources gave the good mycelium growth of oyster mushroom PC, and at 1~3% sucrose concentration, mycelium colony diameter of PC was achieved the maximum value. Ammonium chloride concentrations at 0.03~0.09% and 0.03~0.05% also gave the greatest values in mycelium colony diameter of mushroom PO and PC. Brown rice was found to be the most favourable for mycelium growth of two oyster mushroom species. In addition, sugarcane residue, acasia sawdust and corn cob were selected as favourable lignocellulosic substrate sources for mycelium growth of both oyster mushrooms. PMID:25892910

  15. MPQC: Performance Analysis and Optimization

    SciTech Connect

    Sarje, Abhinav; Williams, Samuel; Bailey, David

    2012-11-30

    MPQC (Massively Parallel Quantum Chemistry) is a widely used computational quantum chemistry code. It is capable of performing a number of computations commonly occurring in quantum chemistry. In order to achieve better performance of MPQC, in this report we present a detailed performance analysis of this code. We then perform loop and memory access optimizations, and measure performance improvements by comparing the performance of the optimized code with that of the original MPQC code. We observe that the optimized MPQC code achieves a significant improvement in the performance through a better utilization of vector processing and memory hierarchies.

  16. Stripping accumulation and optimization of HIMM synchrotron

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  17. Childhood Obesity and Cognitive Achievement.

    PubMed

    Black, Nicole; Johnston, David W; Peeters, Anna

    2015-09-01

    Obese children tend to perform worse academically than normal-weight children. If poor cognitive achievement is truly a consequence of childhood obesity, this relationship has significant policy implications. Therefore, an important question is to what extent can this correlation be explained by other factors that jointly determine obesity and cognitive achievement in childhood? To answer this question, we exploit a rich longitudinal dataset of Australian children, which is linked to national assessments in math and literacy. Using a range of estimators, we find that obesity and body mass index are negatively related to cognitive achievement for boys but not girls. This effect cannot be explained by sociodemographic factors, past cognitive achievement or unobserved time-invariant characteristics and is robust to different measures of adiposity. Given the enormous importance of early human capital development for future well-being and prosperity, this negative effect for boys is concerning and warrants further investigation. PMID:26123250

  18. Using Design To Achieve Sustainability

    EPA Science Inventory

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

  19. Identity Achievement and Axiological Maturity.

    ERIC Educational Resources Information Center

    Simmons, Dale D.

    1983-01-01

    Confirmed the relationship among identity achievement, value competence, and valuing fulfillment, in a study involving 99 college students. Suggested that identity status may reflect axiological maturity, but an increase in the level of such maturity is needed. (JAC)

  20. Purification, growth, fabrication and characterization of wide bandgap materials. Final technical report

    SciTech Connect

    Chen, K.T.; Chen, H.; Burger, A.

    1998-05-01

    Wide bandgap semiconductor single crystals, such as heavy metal halide compounds, have been grown by physical vapor transport and Bridgman methods. Zone-refining and vacuum sublimation techniques were used to purify and adjust the stoichiometric composition of the starting material, and were proven to be effective. Several spectroscopic, microscopic and thermodynamic analytical techniques were employed to investigate the optical, electrical and structural properties of crystals. These results revealed information regarding micro- and macroscopic defects, impurities and modifications resulting from source material, growth process, post-growth treatment and device fabrication. Crystal growth and processing conditions have been correlated with this information and were optimized to achieve the purest and highest quality materials for practical device applications. Future works will involve optimization of material purification and crystal growth processes to produce high purity and low defect crystals, development of sensitive material characterization tools allowing a better understanding of defects formation and their correlation with processing conditions. Developments in bulk crystal growth research for detector devices in the Center for Photonic Materials and Devices since its establishment have been reviewed. Purification processes and single crystal growth systems employing physical vapor transport and Bridgman methods were assembled and used to produce high purity and superior quality wide bandgap materials based on heavy metal halides semiconductors. Comprehensive material characterization techniques have been employed to reveal the optical, electrical and thermodynamic properties of crystals, and the results were used to establish improved material processing procedures.

  1. RF Gun Optimization Study

    SciTech Connect

    Alicia Hofler; Pavel Evtushenko

    2007-07-03

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. A genetic algorithm (GA) has been successfully used to optimize DC photo injector designs at Cornell University [1] and Jefferson Lab [2]. We propose to apply GA techniques to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize a system that has been benchmarked with beam measurements and simulation.

  2. Crystal Growth Control

    NASA Technical Reports Server (NTRS)

    Duval, Walter M. B.; Batur, Celal; Bennett, Robert J.

    1997-01-01

    We present an innovative design of a vertical transparent multizone furnace which can operate in the temperature range of 25 C to 750 C and deliver thermal gradients of 2 C/cm to 45 C/cm for the commercial applications to crystal growth. The operation of the eight zone furnace is based on a self-tuning temperature control system with a DC power supply for optimal thermal stability. We show that the desired thermal profile over the entire length of the furnace consists of a functional combination of the fundamental thermal profiles for each individual zone obtained by setting the set-point temperature for that zone. The self-tuning system accounts for the zone to zone thermal interactions. The control system operates such that the thermal profile is maintained under thermal load, thus boundary conditions on crystal growth ampoules can be predetermined prior to crystal growth. Temperature profiles for the growth of crystals via directional solidification, vapor transport techniques, and multiple gradient applications are shown to be easily implemented. The unique feature of its transparency and ease of programming thermal profiles make the furnace useful for scientific and commercial applications for the determination of process parameters to optimize crystal growth conditions.

  3. Growth of (indium,aluminum)gallium nitride alloys by RF-plasma assisted molecular beam epitaxy for application in high electron mobility transistor structures

    NASA Astrophysics Data System (ADS)

    Poblenz, Christiane

    In this thesis work, growth of (In,Al)GaN alloys by molecular beam epitaxy (MBE) was investigated with the goal of developing these materials for application in high electron mobility transistor structures (HEMTs). Growth of InGaN alloys by MBE was investigated in detail with the objective of implementing InGaN channels into HEMT structures to improve device performance. A growth diagram for InGaN growth based on III/V ratio during growth was developed. Control of indium composition was studied in detail and found to be highly dependent upon several growth parameters. Systematic studies resulted in demonstration of complete compositional control during growth of InGaN across the entire compositional range. Implementation of these layers into HEMT structures yielded inferior device properties due to an extremely high level of unintentional background carriers in the InGaN channel. Transport measurements were done on bulk InGaN for the first time demonstrating carrier concentrations as high as 1018 cm-2. An all-MBE growth process for AlGaN/GaN HEMTs on SiC was also developed utilizing an AlN nucleation layer and a two-step growth process for the GaN to reduce and control threading dislocation density. The GaN growth process was structurally and electrically optimized to achieve semi-insulating HEMT buffers. Two methods were developed to reduce buffer leakage. The first was through implementation of carbon doping via CBr4, and the second was by optimization of the AlN nucleation layer growth conditions in unintentionally doped (carbon-free) structures. Optimization of the direct-growth process and elimination of buffer leakage led to record output power densities in MBE-grown AlGaN/GaN HEMTs and device performance which is on par with state-of-the art HEMTs grown by metalorganic chemical vapor deposition (MOCVD).

  4. Growth and study of nonlinear optical materials for frequency conversion devices with applications in defence and security

    NASA Astrophysics Data System (ADS)

    Tassev, V.; Snure, M.; Vangala, S.; Kimani, M.; Peterson, R.; Schunemann, P.

    2014-10-01

    A series of nonlinear materials including GaAs, GaP, and ZnSe have been examined to determine their suitability for non-linear frequency conversion devices (FCD) and more specifically their use as high power, compact and broadly tunable IR and THz sources for defense and security applications. The more mature GaAs was investigated to reveal the causes for the optical losses that restrict achievement of higher conversion efficiency in quasi-phasematched FCD, while the efforts with GaP were oriented in developing simple, cost effective techniques for fabrication of orientation patterned (OP) templates and optimizing the subsequent thick HVPE growth on these templates. Thus, average growth rates of 50- 70 ?m/h were achieved in up to 8-hour long experiments. High optical layer quality was achieved by suitable control of the process parameters. The optimal orientation of the pattern was determined and used as essential feedback aiming to improve the template preparation. This led to the production of the first 300-400 ?m thick device quality OPGaP. Efforts to suppress the parasitic nucleation during growths with longer duration or to achieve thicker layers by a 2 step growth process were also made. The main challenge with the newer candidate, OPZnSe, was to establish suitable regimes for hydrothermal growth on plain (001) ZnSe seeds grown by chemical vapor deposition. Two different temperature ranges, 330-350 °C and 290-330 °C, were investigated. The mineralized concentration was also manipulated to accelerate the growth in (111) direction and, thus, to improve the growth in (001) direction. The next material in the line is GaN. The traditional HVPE approach will be combined with a growth at low reactor pressure. Growths will be performed in the next sequence: growth on thin GaN layers grown by MOCVD on sapphire wafers, growth on half-patterned GaN templates with different orientations and, finally, growth on OPGaN templates.

  5. Role of Prism Decussation on Fatigue Crack Growth and Fracture of Human Enamel

    PubMed Central

    Bajaj, Devendra; Arola, Dwayne

    2009-01-01

    The role of prism decussation on the crack growth resistance of human enamel is evaluated. Miniature inset Compact Tension (CT) specimens embodying a section of cuspal enamel were subjected to Mode I cyclic or monotonic loads. Cracks were grown in either the forward (from outer enamel inwards) or reverse (from inner enamel outwards) direction and the responses were compared quantitatively. Results showed that the outer enamel exhibits lower resistance to the inception and growth of cracks. Regardless of the growth direction, the near threshold region of cyclic extension was typical of ‘short crack’ behavior (i.e. deceleration of growth with an increase in crack length). Cyclic crack growth was more stable in the forward direction and occurred over twice the spatial distance achieved in the reverse direction. In response to the monotonic loads, a rising R-curve response was exhibited by growth in the forward direction only. The total energy absorbed in fracture for the forward direction was more than three times that in the reverse. The rise in crack growth resistance was largely attributed to a combination of mechanisms that included crack bridging, crack bifurcation and crack curving, which were induced by decussation in the inner enamel. An analysis of the responses distinguished that the microstructure of enamel appears optimized for resisting crack growth initiating from damage at the tooth’s surface. PMID:19433137

  6. Convex Functions Smooth Optimization Non-Smooth Optimization Randomized Algorithms Parallel/Distributed Optimization Convex Optimization

    E-print Network

    Marlin, Benjamin

    Convex Functions Smooth Optimization Non-Smooth Optimization Randomized Algorithms Parallel Smooth Optimization Non-Smooth Optimization Randomized Algorithms Parallel/Distributed Optimization Smooth Optimization Non-Smooth Optimization Randomized Algorithms Parallel/Distributed Optimization

  7. Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters

    PubMed Central

    Leach, Michelle K.; Feng, Zhang-Qi; Tuck, Samuel J.; Corey, Joseph M.

    2011-01-01

    Electrospun nanofiber scaffolds have been shown to accelerate the maturation, improve the growth, and direct the migration of cells in vitro. Electrospinning is a process in which a charged polymer jet is collected on a grounded collector; a rapidly rotating collector results in aligned nanofibers while stationary collectors result in randomly oriented fiber mats. The polymer jet is formed when an applied electrostatic charge overcomes the surface tension of the solution. There is a minimum concentration for a given polymer, termed the critical entanglement concentration, below which a stable jet cannot be achieved and no nanofibers will form - although nanoparticles may be achieved (electrospray). A stable jet has two domains, a streaming segment and a whipping segment. While the whipping jet is usually invisible to the naked eye, the streaming segment is often visible under appropriate lighting conditions. Observing the length, thickness, consistency and movement of the stream is useful to predict the alignment and morphology of the nanofibers being formed. A short, non-uniform, inconsistent, and/or oscillating stream is indicative of a variety of problems, including poor fiber alignment, beading, splattering, and curlicue or wavy patterns. The stream can be optimized by adjusting the composition of the solution and the configuration of the electrospinning apparatus, thus optimizing the alignment and morphology of the fibers being produced. In this protocol, we present a procedure for setting up a basic electrospinning apparatus, empirically approximating the critical entanglement concentration of a polymer solution and optimizing the electrospinning process. In addition, we discuss some common problems and troubleshooting techniques. PMID:21304466

  8. Electrospinning fundamentals: optimizing solution and apparatus parameters.

    PubMed

    Leach, Michelle K; Feng, Zhang-Qi; Tuck, Samuel J; Corey, Joseph M

    2011-01-01

    Electrospun nanofiber scaffolds have been shown to accelerate the maturation, improve the growth, and direct the migration of cells in vitro. Electrospinning is a process in which a charged polymer jet is collected on a grounded collector; a rapidly rotating collector results in aligned nanofibers while stationary collectors result in randomly oriented fiber mats. The polymer jet is formed when an applied electrostatic charge overcomes the surface tension of the solution. There is a minimum concentration for a given polymer, termed the critical entanglement concentration, below which a stable jet cannot be achieved and no nanofibers will form - although nanoparticles may be achieved (electrospray). A stable jet has two domains, a streaming segment and a whipping segment. While the whipping jet is usually invisible to the naked eye, the streaming segment is often visible under appropriate lighting conditions. Observing the length, thickness, consistency and movement of the stream is useful to predict the alignment and morphology of the nanofibers being formed. A short, non-uniform, inconsistent, and/or oscillating stream is indicative of a variety of problems, including poor fiber alignment, beading, splattering, and curlicue or wavy patterns. The stream can be optimized by adjusting the composition of the solution and the configuration of the electrospinning apparatus, thus optimizing the alignment and morphology of the fibers being produced. In this protocol, we present a procedure for setting up a basic electrospinning apparatus, empirically approximating the critical entanglement concentration of a polymer solution and optimizing the electrospinning process. In addition, we discuss some common problems and troubleshooting techniques. PMID:21304466

  9. Use of a D-optimal design with constrains to quantify the effects of the mixture of sodium, potassium, calcium and magnesium chloride salts on the growth parameters of Saccharomyces cerevisiae.

    PubMed

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

    2008-08-01

    The combined effect of NaCl, KCl, CaCl(2), and MgCl(2) on the water activity (a (w)) and the growth parameters of Saccharomyces cerevisiae was studied by means of a D-optimal mixture design with constrains (total salt concentrations < or = 9.0%, w/v). The a (w) was linearly related to the concentrations of the diverse salts; its decrease, by similar concentrations of salts, followed the order NaCl > CaCl(2) > KCl > MgCl(2), regardless of the reference concentrations used (total absence of salts or 5% NaCl). The equations that expressed the maximum specific growth (mu (max)), lag phase duration (lambda), and maximum population reached (N (max)) showed that the values of these parameters depended on linear effects and two-way interactions of the studied chloride salts. The mu (max) decreased as NaCl and CaCl(2) increased (regardless of the presence or not of previous NaCl); however, in the presence of a 5% NaCl, a further addition of KCl and MgCl(2) markedly increased mu (max). The lambda was mainly affected by MgCl(2) and the interactions NaCl x CaCl(2) and CaCl(2) x MgCl(2). The further addition of NaCl and CaCl(2) to a 5% NaCl medium increased the lag phase while KCl and MgCl(2) had negligible or slightly negative effect, respectively. N (max) was mainly affected by MgCl(2) and its interactions with NaCl, KCl, and CaCl(2); MgCl(2) stimulated N (max) in the presence of 5% NaCl while KCl, NaCl, and CaCl(2) had a progressive decreasing effect. These results can be of interest for the fermentation and preservation of vegetable products, and foods in general, in which this yeast could be present. PMID:18465155

  10. Mouth Growths

    MedlinePLUS

    ... Multiple bony growths in the mouth may indicate familial adenomatous polyposis, a hereditary disorder of the digestive tract where ... in the colon that often become cancerous (see Familial Adenomatous Polyposis ). Keratoacanthomas (see Keratoacanthomas ) are growths that form on ...

  11. The economics of optimal urban groundwater management in southwestern USA

    NASA Astrophysics Data System (ADS)

    Hansen, Jason K.

    2012-08-01

    Groundwater serves as the primary water source for approximately 80% of public water systems in the United States, and for many more as a secondary source. Traditionally management relies on groundwater to meet rising demand by increasing supply, but climate uncertainty and population growth require more judicious management to achieve efficiency and sustainability. Over-pumping leads to groundwater overdraft and jeopardizes the ability of future users to depend on the resource. Optimal urban groundwater pumping can play a role in solving this conundrum. This paper investigates to what extent and under what circumstances controlled pumping improves social welfare. It considers management in a hydro-economic framework and finds the optimal pumping path and the optimal price path. These allow for the identification of the social benefit of controlled pumping, and the scarcity rent, which is one tool to sustainably manage groundwater resources. The model is numerically illustrated with a case study from Albuquerque, New Mexico (USA). The Albuquerque results indicate that, in the presence of strong demand growth, controlled pumping improves social welfare by 22%, extends use of the resource, and provides planners with a mechanism to advance the economic sustainability of groundwater.

  12. Optimal control

    NASA Astrophysics Data System (ADS)

    Sargent, R. W. H.

    2000-12-01

    This paper gives a brief historical survey of the development of the theory of the calculus of variations and optimal control, and goes on to review the different approaches to the numerical solution of optimal control problems.

  13. Dynamic Optimization

    NASA Technical Reports Server (NTRS)

    Laird, Philip

    1992-01-01

    We distinguish static and dynamic optimization of programs: whereas static optimization modifies a program before runtime and is based only on its syntactical structure, dynamic optimization is based on the statistical properties of the input source and examples of program execution. Explanation-based generalization is a commonly used dynamic optimization method, but its effectiveness as a speedup-learning method is limited, in part because it fails to separate the learning process from the program transformation process. This paper describes a dynamic optimization technique called a learn-optimize cycle that first uses a learning element to uncover predictable patterns in the program execution and then uses an optimization algorithm to map these patterns into beneficial transformations. The technique has been used successfully for dynamic optimization of pure Prolog.

  14. Delayed growth

    MedlinePLUS

    Growth - slow (child 0 - 5 years); Weight gain - slow (child 0 - 5 years); Slow rate of growth; Retarded growth and development; ... A child should have regular, well-baby check-ups with a health care provider. These checkups are usually scheduled ...

  15. Goal Setting to Achieve Results

    ERIC Educational Resources Information Center

    Newman, Rich

    2012-01-01

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

  16. Socioeconomic Determinants of Academic Achievement

    ERIC Educational Resources Information Center

    Tomul, Ekber; Savasci, Havva Sebile

    2012-01-01

    This study aims to investigate the relationship between academic achievement and the socioeconomic characteristics of elementary school 7th grade students in Burdur. The population of the study are 7th grade students who had education at elementary schools in Burdur in the 2007-2008 academic year. Two staged sampling was chosen as suitable for the…

  17. Potential-Based Achievement Goals

    ERIC Educational Resources Information Center

    Elliot, Andrew; Murayama, Kou; Kobeisy, Ahmed; Lichtenfeld, Stephanie

    2015-01-01

    Background: Self-based achievement goals use one's own intrapersonal trajectory as a standard of evaluation, and this intrapersonal trajectory may be grounded in one's past (past-based goals) or one's future potential (potential-based goals). Potential-based goals have been overlooked in the literature to date. Aims: The primary aim of the present…

  18. Washington State's Student Achievement Initiative

    ERIC Educational Resources Information Center

    Pettitt, Maureen; Prince, David

    2010-01-01

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

  19. Educational Achievement and Sex Discrimination.

    ERIC Educational Resources Information Center

    Mullis, Ina V. S.

    In the past years the National Assessment of Educational Progress (NAEP) has released results from a variety of learning areas. The purpose of this paper is to point out male-female differences in achievement across several learning areas. Hopefully, the results discussed here will be used as a basis for examining the possible existence of social…

  20. Explaining Achievement in Higher Education

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  1. The Widening Income Achievement Gap

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2013-01-01

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

  2. ACHIEVING DEXTEROUS MANIPULATION FOR MINIMALLY

    E-print Network

    Wu, Mingshen

    ;Hydraulics offers advantages for surgical manipulators. 5 #12;6 #12;The components are housed withinACHIEVING DEXTEROUS MANIPULATION FOR MINIMALLY INVASIVE SURGICAL ROBOTS THROUGH THE USE OF HYDRAULICS Devin R. Berg*, Perry Y. Li, and Arthur G. Erdman Department of Mechanical Engineering University

  3. Achieving world class maintenance status

    SciTech Connect

    Tomlingson, P.D.

    2007-08-15

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

  4. Meeting a Math Achievement Crisis

    ERIC Educational Resources Information Center

    Jennings, Lenora; Likis, Lori

    2005-01-01

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

  5. The Achievement-Assessment Link

    ERIC Educational Resources Information Center

    Wallace, Virginia; Husid, Whitney

    2011-01-01

    The recent recession, school budget cuts, and predictions of school libraries' demise because of technology advances put pressure on school librarians to prove the utility, relevance, and value of school libraries to student learning. While national studies document that school libraries increase student achievement, school librarians must…

  6. Dream It. Achieve It. Scholarships

    E-print Network

    Indiana University

    Dream It. Achieve It. Scholarships and Financial Aid INDIANA UNIVERSITY BLOOMINGTON #12;A great in external scholarship money. $23,000,000+ #12;Scholarships and You There's nothing better than investing millions of dollars in scholarships to hard-working and talented students to make their college dreams

  7. Dream It. Achieve It. Scholarships

    E-print Network

    Indiana University

    Dream It. Achieve It. Scholarships and Financial Aid IndIAnA UnIverSIty Bloomington #12;explore at IU with more than $22M in external scholarship money. $22,000,000+ #12;Scholarships and you There your goals. Every year, IU awards millions of dollars in scholarships to hard-working and talented

  8. Television Viewing and Mathematics Achievement.

    ERIC Educational Resources Information Center

    Paik, Haejung

    A study examined the correlation between mathematics achievement and television viewing, and explored the underlying processes. Data were gathered from 13,542 high school seniors from the first wave of the High School and Beyond project, conducted by the National Opinion Research Center on behalf of the National Center for Education Statistics. A…

  9. Scheduling and Achievement. Research Brief

    ERIC Educational Resources Information Center

    Walker, Karen

    2006-01-01

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

  10. School Districts and Student Achievement

    ERIC Educational Resources Information Center

    Chingos, Matthew M.; Whitehurst, Grover J.; Gallaher, Michael R.

    2015-01-01

    School districts are a focus of education reform efforts in the United States, but there is very little existing research about how important they are to student achievement. We fill this gap in the literature using 10 years of student-level, statewide data on fourth- and fifth-grade students in Florida and North Carolina. A variance decomposition…

  11. Can Judges Improve Academic Achievement?

    ERIC Educational Resources Information Center

    Greene, Jay P.; Trivitt, Julie R.

    2008-01-01

    Over the last 3 decades student achievement has remained essentially unchanged in the United States, but not for a lack of spending. Over the same period a myriad of education reforms have been suggested and per-pupil spending has more than doubled. Since the 1990s the education reform attempts have frequently included judicial decisions to revise…

  12. Achieving safe femoral arterial access.

    PubMed

    Lee, Michael S; Kong, Jeremy

    2015-06-01

    Percutaneous coronary intervention can lead to vascular access complications that prolong patient hospital stay and costs as well as increase patient morbidity and mortality. Given its ease of use and familiarity, transfemoral access is still the preferred method of approach by many operators. The transfemoral approach is used when large bore access is required or if transradial access is not feasible due to variations in the anatomy of the upper extremity artery. The use of fluoroscopy, ultrasonography, and femoral angiography can help the operator obtain proper arteriotomy of the common femoral artery. Measures to decrease vascular access complications include proper technique, optimal pharmacotherapy, and avoiding the use of arterial sheaths >6 Fr. Optimal pharmacotherapy includes the use of bivalirudin and weight-based unfractionated heparin to avoid supratherapeutic activated clotting times, and to avoid glycoprotein IIb/IIIa inhibitors. When used appropriately, vascular closure devices can decrease the risk of bleeding complications. Randomized trials are needed to confirm these recommendations. PMID:25911441

  13. Harming the Best: How Schools Affect the Black-White Achievement Gap. NBER Working Paper No. 14211

    ERIC Educational Resources Information Center

    Hanushek, Eric A.; Rivkin, Steven G.

    2008-01-01

    Sizeable achievement differences by race appear in early grades, but substantial uncertainty exists about the impact of school quality on the black-white achievement gap and particularly about its evolution across different parts of the achievement distribution. Texas administrative data show that the overall growth in the achievement gap between…

  14. Thermoacoustic Refrigerator's Stack Optimization

    NASA Astrophysics Data System (ADS)

    El-Fawal, Mawahib Hassan; Mohd-Ghazali, Normah; Yaacob, Mohd. Shafik; Darus, Amer Nordin

    2010-06-01

    The standing wave thermoacoustic refrigerator, which uses sound generation to transfer heat, was developed rapidly during the past four decades. It was regarded as a new, promising and environmentally benign alternative to conventional compression vapor refrigerators, although it was not competitive regarding the coefficient of performance (COP) yet. Thus the aim of this paper is to enhance thermoacoustic refrigerator's stack performance through optimization. A computational optimization procedure of thermoacoustic stack design was fully developed. The procedure was designed to achieve optimal coefficient of performance based on most of the design and operating parameters. Cooling load and acoustic power governing equations were set assuming the linear thermoacoustic theory. Lagrange multipliers method was used as an optimization technique tool to solve the governing equations. Numerical analyses results of the developed design procedure are presented. The results showed that the stack design parameters are the most significant parameters for the optimal overall performance. The coefficient of performance obtained increases by about 48.8% from the published experimental optimization methods. The results are in good agreement with past established studies.

  15. Growth of vertical-cavity surface emitting lasers by metalorganic vapor phase epitaxy

    SciTech Connect

    Hou, H.Q.; Hammons, B.E.; Crawford, M.H.; Lear, K.L.; Choquette, K.D.

    1996-10-01

    We present growth and characterization of visible and near-infrared vertical-cavity surface emitting lasers (VCSELs) grown by metalorganic vapor phase epitaxy. Discussions on the growth issue of VCSEL materials include growth rate and composition control using an {ital in}{ital situ} normal-incidence reflectometer, comprehensive p- and n-type doping study in AlGaAs by CCl{sub 4} and Si{sub 2}H{sub 6} over the entire composition range, and optimization of ultra-high material uniformity. We also demonstrate our recent achievements of all-AlGaAs VCSELs which include the first room-temperature continuous- wave demonstration of 700-nm red VCSELs and high-efficiency and low- threshold voltage 850-nm VCSELs.

  16. Optimal Centroid Position Estimation

    SciTech Connect

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

    2004-07-23

    The alignment of high energy laser beams for potential fusion experiments demand high precision and accuracy by the underlying positioning algorithms. This paper discusses the feasibility of employing online optimal position estimators in the form of model-based processors to achieve the desired results. Here we discuss the modeling, development, implementation and processing of model-based processors applied to both simulated and actual beam line data.

  17. Prescribing Posttraumatic Growth.

    PubMed

    Harbin, Ami

    2015-11-01

    This article introduces questions in psychiatric ethics regarding the substantial field of qualitative and quantitative research into 'posttraumatic growth', which investigates how, after devastating experiences, individuals can come to feel that they have developed warmer relationships, increased spirituality, or a clearer vision of their priorities. In one area of this research, researchers of posttraumatic growth outline strategies for clinicians interested in assisting their patients in achieving such growth. In this article, I articulate two ethical concerns about this account of posttraumatic growth and the practice of growth-oriented therapy. The first is a concern about the status and effects of the ideal of posttraumatic health implicit in their account, and the second a concern about the ethical implications of the clinical recommendations for the post-trauma patient. I argue for the need for more attention to the hazardous implications of relating to patients as though they are on their way to, and themselves largely in control of, their own posttraumatic growth. PMID:25908490

  18. Enhanced thermal conductivity of polycrystalline aluminum nitride thin films by optimizing the interface structure

    NASA Astrophysics Data System (ADS)

    Pan, T. S.; Zhang, Y.; Huang, J.; Zeng, B.; Hong, D. H.; Wang, S. L.; Zeng, H. Z.; Gao, M.; Huang, W.; Lin, Y.

    2012-08-01

    The growth-temperature dependency and interface structure effects on the thermal conductivity of the highly textured AlN thin films on (001) Si substrates were systematically studied by characterizing the crystal structures, surface morphologies, interface structures, chemical compositions, and thermal conductivity using x-ray diffraction analysis, atomic force microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and 3-omega method, respectively. By optimizing the interface microstructure and the growth temperature, thermal conductivity of polycrystalline AlN thin films can be greatly enhanced from 9.9 to 26.7 W/mK, when the growth temperature increases from 330 to 560 °C. This achievement is considered to be associated with the diminishment of the amorphous and disordered layer at the AlN/Si interface.

  19. Optimal quantum cloning via spin networks

    SciTech Connect

    Chen Qing; Cheng Jianhua; Wang Kelin; Du Jiangfeng

    2006-09-15

    In this paper we demonstrate that optimal 1{yields}M phase-covariant cloning quantum cloning is available via free dynamical evolution of spin networks. By properly designing the network and the couplings between spins, we show that optimal 1{yields}M phase-covariant cloning can be achieved if the initial state is prepared as a specific symmetric state. Especially, when M is an odd number, the optimal phase-covariant cloning can be achieved without ancillas. Moreover, we demonstrate that the same framework is capable for optimal 1{yields}2 universal cloning.

  20. Achieving the Holevo bound via a bisection decoding protocol

    E-print Network

    Matteo Rosati; Vittorio Giovannetti

    2015-06-29

    We present a new decoding protocol to realize transmission of classical information through a quantum channel at asymptotically maximum capacity, achieving the Holevo bound and thus the optimal communication rate. At variance with previous proposals, our scheme recover the message bit by bit, making use of a series "yes-no" measurements, organized in bisection fashion, thus determining which codeword was sent in logN steps, N being the number of codewords.

  1. Recombinant collagen production optimization in Escherichia coli

    E-print Network

    Whittemore, Brett A

    2005-01-01

    An Escherichia coli-based collagen-production process was used to investigate several process optimization objectives for use at the industrial scale. The effect of cooling on fermentation growth kinetics was studied, with ...

  2. Metabolism at Evolutionary Optimal States

    PubMed Central

    Rabbers, Iraes; van Heerden, Johan H.; Nordholt, Niclas; Bachmann, Herwig; Teusink, Bas; Bruggeman, Frank J.

    2015-01-01

    Metabolism is generally required for cellular maintenance and for the generation of offspring under conditions that support growth. The rates, yields (efficiencies), adaptation time and robustness of metabolism are therefore key determinants of cellular fitness. For biotechnological applications and our understanding of the evolution of metabolism, it is necessary to figure out how the functional system properties of metabolism can be optimized, via adjustments of the kinetics and expression of enzymes, and by rewiring metabolism. The trade-offs that can occur during such optimizations then indicate fundamental limits to evolutionary innovations and bioengineering. In this paper, we review several theoretical and experimental findings about mechanisms for metabolic optimization. PMID:26042723

  3. State Growth Models for School Accountability: Progress on Development and Reporting Measures of Student Growth

    ERIC Educational Resources Information Center

    Blank, Rolf K.

    2010-01-01

    The Council of Chief State School Officers (CCSSO) is working to respond to increased interest in the use of growth models for school accountability. Growth models are based on tracking change in individual student achievement scores over multiple years. While growth models have been used for decades in academic research and program evaluation, a…

  4. Economic growth and carbon emission control

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu

    The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal policies of emissions control required for achieving the social goal in a private context. The results suggest that the efficiency of abatement technology is crucial for the timing of executing the emission tax. And emission tax is preferred to an input tax, as long as the detection of emissions is not costly and abatement technology is efficient. Keywords: Economic growth, Carbon emission, Power generation, Joint production, China

  5. Hierarchical chirality transfer in the growth of Towel Gourd tendrils

    E-print Network

    Qin, Qinghua

    Hierarchical chirality transfer in the growth of Towel Gourd tendrils Jian-Shan Wang1,2 , Gang Wang unclear. In this paper, we investigate how the Towel Gourd tendrils achieve their chiral growth. Our

  6. Within-Teacher Variation of Causal Attributions of Low Achieving Students

    ERIC Educational Resources Information Center

    Jager, Lieke; Denessen, Eddie

    2015-01-01

    In teacher research, causal attributions of low achievement have been proven to be predictive of teachers' efforts to provide optimal learning contexts for all students. In most studies, however, attributions have been studied as a between-teacher variable rather than a within-teacher variable assuming that teachers' responses to low achievement

  7. Parental Warmth, Control, and Involvement in Schooling: Predicting Academic Achievement among Korean American Adolescents.

    ERIC Educational Resources Information Center

    Kim, Kyoungho; Rohner, Ronald P.

    2002-01-01

    Explored the relationship between parenting style and academic achievement of Korean American adolescents, investigating the influence of perceived parental warmth and control and improvement in schooling. Survey data indicated that authoritative paternal parenting related to optimal academic achievement. Differences in maternal parenting styles…

  8. Optimal life-cycle profiles of fertility and labor supply.

    PubMed

    Moffitt, R

    1984-01-01

    A model of life cycle fertility is developed using the language and framework of optimal control theory. The chief characteristic of children that distinguishes them from other consumer durables is, in the language of the optimal growth theory, the "irreversibility of investment." As the good does not depreciate in the ordinary sense, the stock must be monotonically nondecreasing over time. The optimal profile of fertility is, for this reason, characterized by the same type of "bang-bang" behavior found in many optimal growth problems. Yet, the fertility decision is complicated considerably by several other factors. Chief among these is the intrinsic relation to the labor-supply decision, for having children implies inevitable constraints on the mother's or father's time. Thus, optimal labor-supply decisions also must be considered. The model is developed in stages, proceeding from very simple to the more complex models. 1 section introduces the impact of fertility on the future demands for home time. It is shown that optimal fertility profiles follow turnpike paths similar to those in the growth-theory literature. A subsequent section introduces labor-supply and human-captial considerations. As the models become more complex, solutions become harder to derive and are often only outlined. The analysis provides some theoretical basis for expecting certain shapes of the life-cycle profiles of fertility, labor supply, and wages. Fertility profiles may be of 2 shapes--one beginning at a high rate, falling to a lower rate, then to zero; and one beginning at zero, rising to a moderate rate, then falling back down to zero. Labor supply profiles can be of a number of different shapes, but the impact of childbearing is to lower hours worked during the early childrearing period. As the children mature, hours worked rise (or at least fall more slowly) as home time responsibilities lessen, although the level to which they rise will probably be lower than before the 1st birth. Log-wage profiles rise during the period before the 1st birth, then either fall or rise more slowly during the early years of childbearing, and then rise again as the children mature. These shapes have been inferred from a control-theory model that is quite complex and which could use considerably more delineation than has been achieved here. Closed-form solutions to the model have not been obtained, nor have any formal comparative dynamics been performed. As the model stands it is too complex to be empirically implemented. Such implementation would be desirable. PMID:12266417

  9. Risk modelling in portfolio optimization

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    Risk management is very important in portfolio optimization. The mean-variance model has been used in portfolio optimization to minimize the investment risk. The objective of the mean-variance model is to minimize the portfolio risk and achieve the target rate of return. Variance is used as risk measure in the mean-variance model. The purpose of this study is to compare the portfolio composition as well as performance between the optimal portfolio of mean-variance model and equally weighted portfolio. Equally weighted portfolio means the proportions that are invested in each asset are equal. The results show that the portfolio composition of the mean-variance optimal portfolio and equally weighted portfolio are different. Besides that, the mean-variance optimal portfolio gives better performance because it gives higher performance ratio than the equally weighted portfolio.

  10. Achieving Quality in Occupational Health

    NASA Technical Reports Server (NTRS)

    O'Donnell, Michele (Editor); Hoffler, G. Wyckliffe (Editor)

    1997-01-01

    The conference convened approximately 100 registered participants of invited guest speakers, NASA presenters, and a broad spectrum of the Occupational Health disciplines representing NASA Headquarters and all NASA Field Centers. Centered on the theme, "Achieving Quality in Occupational Health," conferees heard presentations from award winning occupational health program professionals within the Agency and from private industry; updates on ISO 9000 status, quality assurance, and information technologies; workshops on ergonomics and respiratory protection; an overview from the newly commissioned NASA Occupational Health Assessment Team; and a keynote speech on improving women's health. In addition, NASA occupational health specialists presented 24 poster sessions and oral deliveries on various aspects of current practice at their field centers.

  11. Parallel VLSI Circuit Analysis and Optimization 

    E-print Network

    Ye, Xiaoji

    2012-02-14

    circuit simulation techniques and achieves superlinear speedup in practice. The second part of the dissertation talks about parallel circuit optimization. A modified asynchronous parallel pattern search (APPS) based method which utilizes the efficient...

  12. Time-optimal control with finite bandwidth

    E-print Network

    M. Hirose; P. Cappellaro

    2015-11-24

    Optimal control theory provides recipes to achieve quantum operations with high fidelity and speed, as required in quantum technologies such as quantum sensing and computation. While technical advances have achieved the ultrastrong driving regime in many physical systems, these capabilities have yet to be fully exploited for the precise control of quantum systems, as other limitations, such as the generation of higher harmonics or the finite bandwidth of the control fields, prevent the implementation of theoretical time-optimal control. Here we present a method to achieve time-optimal control of qubit systems that can take advantage of fast driving beyond the rotating wave approximation. We exploit results from optimal control theory to design driving protocols that can be implemented with realistic, finite-bandwidth control and we find a relationship between bandwidth limitations and achievable control fidelity.

  13. Dispositional optimism.

    PubMed

    Carver, Charles S; Scheier, Michael F

    2014-06-01

    Optimism is a cognitive construct (expectancies regarding future outcomes) that also relates to motivation: optimistic people exert effort, whereas pessimistic people disengage from effort. Study of optimism began largely in health contexts, finding positive associations between optimism and markers of better psychological and physical health. Physical health effects likely occur through differences in both health-promoting behaviors and physiological concomitants of coping. Recently, the scientific study of optimism has extended to the realm of social relations: new evidence indicates that optimists have better social connections, partly because they work harder at them. In this review, we examine the myriad ways this trait can benefit an individual, and our current understanding of the biological basis of optimism. PMID:24630971

  14. Dispositional Optimism

    PubMed Central

    Carver, Charles S.; Scheier, Michael F.

    2014-01-01

    Optimism is a cognitive construct (expectancies regarding future outcomes) that also relates to motivation: optimistic people exert effort, whereas pessimistic people disengage from effort. Study of optimism began largely in health contexts, finding positive associations between optimism and markers of better psychological and physical health. Physical health effects likely occur through differences in both health-promoting behaviors and physiological concomitants of coping. Recently, the scientific study of optimism has extended to the realm of social relations: new evidence indicates that optimists have better social connections, partly because they work harder at them. In this review, we examine the myriad ways this trait can benefit an individual, and our current understanding of the biological basis of optimism. PMID:24630971

  15. Optimization of pre-sowing magnetic field doses through RSM in pea

    NASA Astrophysics Data System (ADS)

    Iqbal, M.; Ahmad, I.; Hussain, S. M.; Khera, R. A.; Bokhari, T. H.; Shehzad, M. A.

    2013-09-01

    Seed pre-sowing magnetic field treatment was reported to induce biochemical and physiological changes. In the present study, response surface methodology was used for deduction of optimal magnetic field doses. Improved growth and yield responses in the pea cultivar were achieved using a rotatable central composite design and multivariate data analysis. The growth parameters such as root and shoot fresh masses and lengths as well as yield were enhanced at a certain magnetic field level. The chlorophyll contents were also enhanced significantly vs. the control. The low magnetic field strength for longer duration of exposure/ high strength for shorter exposure were found to be optimal points for maximum responses in root fresh mass, chlorophyll `a' contents, and green pod yield/plant, respectively and a similar trend was observed for other measured parameters. The results indicate that the magnetic field pre-sowing seed treatment can be used practically to enhance the growth and yield in pea cultivar and response surface methodology was found an efficient experimental tool for optimization of the treatment level to obtain maximum response of interest.

  16. Parasites shape the optimal investment in immunity

    E-print Network

    Richner, Heinz

    Parasites shape the optimal investment in immunity Barbara Tschirren* and Heinz Richner The evolution of optimal functioning and maintenance of the immune system is thought to be driven by the costs arising from the allocation of resources to immune functions rather than to growth and reproduction

  17. Integrated multidisciplinary design optimization of rotorcraft

    NASA Technical Reports Server (NTRS)

    Adelman, Howard M.; Mantay, Wayne R.

    1989-01-01

    The NASA/Army research plan for developing the logic elements for helicopter rotor design optimization by integrating appropriate disciplines and accounting for important interactions among the disciplines is discussed. The optimization formulation is described in terms of the objective function, design variables, and constraints. The analysis aspects are discussed, and an initial effort at defining the interdisciplinary coupling is summarized. Results are presented on the achievements made in the rotor dynamic optimization for vibration reduction, rotor structural optimization for minimum weight, and integrated aerodynamic load/dynamics optimization for minimum vibration and weight.

  18. Response-surface-based optimization of 0.1-?m PMOSFETs with ultrathin gate stack dielectrics

    NASA Astrophysics Data System (ADS)

    Srivastava, Anadi; Osburn, Carlton M.

    1998-09-01

    An optimal design for 0.1 micrometer PMOS, consistent with SIA-NTRS Roadmap projections, is developed using a Response Surface methodology (RSM). The impact of four different low thermal budget growth and deposition gate dielectric processes (Furnace oxidation, Rapid Thermal Oxidation (RTO), Rapid Thermal CVD (RTCVD) and Remote Plasma Enhanced CVD (RPECVD) on the design optimization is examined. A Design Of Experiments (DOE) approach was independently employed in each case with simulated baseline surface channel PMOSFET structures having a 2.0 nm gate oxide to statistically explore the channel and extension junction parameter spaces. Channel and extension junction parameters were separately optimized, with channel optimization performed for both doubly-implanted and uniformly doped channels. The condition for constrained optimization was the maximization of Isat at the NTRS Roadmap specified Ioff value of 3 nA/micrometer. A 20% manufacturing tolerance in channel length was factored into the optimization strategy by measuring both Isat and Ioff under their respective worst case tolerance conditions. Optimal designs with modestly differing implant specifications but exhibiting largely comparable performance characteristics were identified for each gate stack. Excellent current drivability of 279 (mu) A/micrometer was obtained at the nominal Leff of 70 nm. Optimized doubly-implanted channels provide 7.5% higher current than the uniformly doped ones. Optimum extension junction design was achieved by a high surface concentration of 2 X 1020 cm-3, extension depth of 32 nm and spacer width of 49 nm, and the analysis clearly revealed that a necessary condition for junction optimization was the onset of drain decoupling from the channel.

  19. An improved medium for the anaerobic growth of Paracoccus denitrificans Pd1222

    PubMed Central

    Hahnke, Stefanie M.; Moosmann, Philipp; Erb, Tobias J.; Strous, Marc

    2014-01-01

    Paracoccus denitrificans is a well studied model organism with respect to its aerobic and anaerobic respiratory enzymes. However, until now, the growth medium for this organism has not been optimized for anaerobic growth. In particular, the requirements of P. denitrificans for trace elements (TEs) are not well known. In the present study we aimed to improve growth rates of P. denitrificans Pd1222 on a defined medium under anoxic conditions. We designed media containing different combinations of TEs at various concentrations, and tested their performance against previously reported media. Our results suggest that growth rate and yield depend on the availability and concentration of TEs in the medium. A chelated TE solution was more suitable than an acidified TE solution. Highest growth rates were achieved with medium comprising the TEs iron, manganese, molybdenum, copper and zinc ranging from 0.1 to 9 ?M. On this medium, P. denitrificans Pd1222 grew with a generation time of 4.4 h under anoxic conditions and 2.8 h under oxic conditions. Diauxic growth was clearly shown with respect to nitrate and nitrite reduction under anoxic conditions. PMID:24550891

  20. Web-dendritic ribbon growth

    NASA Technical Reports Server (NTRS)

    Hilborn, R. B., Jr.; Faust, J. W., Jr.

    1976-01-01

    A web furnace was constructed for pulling dendritic-web samples. The effect of changes in the furnace thermal geometry on the growth of dendritic-web was studied. Several attempts were made to grow primitive dendrites for use as the dendritic seed crystals for web growth and to determine the optimum twin spacing in the dendritic seed crystal for web growth. Mathematical models and computer programs were used to determine the thermal geometries in the susceptor, crucible melt, meniscus, and web. Several geometries were determined for particular furnace geometries and growth conditions. The information obtained was used in conjunction with results from the experimental growth investigations in order to achieve proper conditions for sustained pulling of two dendrite web ribbons. In addition, the facilities for obtaining the following data were constructed: twin spacing, dislocation density, web geometry, resistivity, majority charge carrier type, and minority carrier lifetime.

  1. Academic Achievement Trajectories of Adolescents from Mexican and East Asian Immigrant Families in the United States

    ERIC Educational Resources Information Center

    Jeong, Yu-Jin; Acock, Alan C.

    2014-01-01

    Drawing on the National Educational Longitudinal Survey 1988 (NELS:88), this study identified (1) the growth pattern of academic achievement of adolescent children from Mexican and East Asian immigrant families; (2) investigated to what extent ethnicity and family capital influenced the trajectories in the academic achievement of children from…

  2. Examining School Effects on Achievement: A Conceptual Model and an Example.

    ERIC Educational Resources Information Center

    Fillos, Rita M.; Bowman, Clair Michael

    This paper describes an adaptation of Dyer's regression model that uses data on individual students in an attempt to isolate the influence of different schools on variations in student achievement growth. This procedure involves comparing the results of a multiple regression analysis of individual student achievement scores and several…

  3. Changes in Self-Esteem across the First Year in College: The Role of Achievement Goals

    ERIC Educational Resources Information Center

    Shim, Sungok Serena; Ryan, Allison M.; Cassady, Jerrell

    2012-01-01

    This longitudinal study examined the effects of achievement goals on the growth trajectories of self-esteem during the first-year at a comprehensive public university. College freshmen (N = 311) were followed for one academic year with three time points. Between-individual differences and within-individual change in achievement goals were…

  4. Improving Education Achievement and Attainment in Luxembourg. OECD Economics Department Working Papers, No. 508

    ERIC Educational Resources Information Center

    Carey, David; Ernst, Ekkehard

    2006-01-01

    Improving education achievement in Luxembourg is a priority for strengthening productivity growth and enhancing residents' employment prospects in the private sector, where employers mainly hire cross-border workers. Student achievement in Luxembourg is below the OECD average according to the 2003 OECD PISA study, with the performance gap between…

  5. The Forms of Capital and the Developed Achievement of Black Males

    ERIC Educational Resources Information Center

    Dixon-Román, Ezekiel J.

    2013-01-01

    This study sought to examine the association of the various forms of capital on the developed achievement of Black males. As one of the richest longitudinal family economic data sets, the Child Development Supplement to the Panel Study of Income Dynamics is used to estimate multilevel growth models of the math and reading achievement of Black…

  6. From conformal overgrowth to lateral growth of indium arsenide nano structures on silicon substrates by MOVPE

    NASA Astrophysics Data System (ADS)

    Sladek, Kamil; Haas, Fabian; Heidelmann, Markus; Park, Daesung; Barthel, Juri; Dorn, Falk; Weirich, Thomas E.; Grützmacher, Detlev; Hardtdegen, Hilde

    2013-05-01

    A methodology for the deposition of lateral InAs nanostructures on silicon by selective area metal organic vapor phase epitaxy (SA-MOVPE) is presented. Growth parameters which are optimal for the SA-MOVPE of conformal InAs overgrowth on GaAs nanowires were transferred to the lateral SA growth of InAs structures on patterned silicon substrates. The substrate pretreatment conditions and growth parameters were further optimized with respect to selectivity and nanostructure morphology. It is found that lateral growth of InAs nano structures can be achieved on patterned Si(110) as well as on patterned silicon on insulator (SOI) substrates. An investigation of the laterally grown InAs/Si nanowires' crystal structure revealed a faceted but nevertheless abrupt Si-InAs interface on the Si(110) substrate as well as relaxation and a high crystallinity of the deposited InAs on both Si template types. The morphology and crystallinity of laterally grown structures are discussed in detail and compared to that of vertical shell/core InAs/GaAs nanowires.

  7. Epitaxial Growth of Silicon on Poly-Crystalline Si Seed layer at Low Temperature by Using Hot Wire Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Aldawsari, Manal Abdullah

    There has been a growing interest in using low cost material as a substrate for the large grained polycrystalline silicon photovoltaic devices. The main property of those devices is the potential of obtaining high efficiency similar to crystalline Si devices efficiency yet at much lower cost because of the thin film techniques. Epitaxial growth of Si at low temperatures on low cost large grained seed layers, prepared by aluminum induced crystallization method (AIC), using hot wire chemical vapor deposition (HWCVD) system is investigated in this thesis. In this work, different parameters have been studied in order to optimize the growth to reach the goal of epitaxial growth. The growth of epitaxial silicon using HWCVD system is controlled by four parameters: flow rate of gases, pressure, substrate temperature and filament temperature. As a result, in this work, those four factors were varied to optimize the growth process. Crystallinity quality is a significant factor toward confirming the epitaxial layer. Raman scattering, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM) were used to determine the crystallinity. Epitaxial growth of Si at 500 °C was obtained even with a low vacuum of 1x10-3 torr. Furthermore, heavily doped large grained polycrystalline silicon seed layers were formed at first using AIC on Indium Tin Oxide (ITO) coated glass substrates to be ready for the following step which was epitaxial growth of Si. The grains were continues in the center of the film which was a single crystal that no one has reported it before. Epitaxial growth of Si was successfully achieved as the SEM results showed similar grain sizes before the epitaxial growth and after the epitaxial growth. The TEM results confirmed the epitaxial growth but stacking faults were observed. Also, different orientations were present as Moire Fringes was seen in the TEM images.

  8. Causality orientations, failure, and achievement.

    PubMed

    Koestner, R; Zuckerman, M

    1994-09-01

    Two studies examined similarities between Deci and Ryan's (1985) causality orientations theory and Dweck and Leggett's (1988) social-cognitive theory of achievement. Study 1 examined the conceptual similarity between the individual difference measures central to the two theories. It was shown that autonomous college students are likely to adopt learning goals and report high confidence in their academic abilities; controlled students are likely to adopt performance goals and to report high levels of confidence in their ability; and impersonal students are likely to possess the classic helpless pattern of performance goals and low confidence in their academic abilities. Study 2 examined whether causality orientations, like Dweck's measures of goals and confidence, moderate the impact of failure feedback on motivation as measured in persistence and performance. The results suggested that autonomous individuals respond to failure in a mastery-oriented fashion, whereas impersonal individuals respond in a helpless manner. The response of controlled individuals to failure parallels that of people described as ego-involved or reactive. PMID:7965562

  9. Academic Achievement Among Juvenile Detainees.

    PubMed

    Grigorenko, Elena L; Macomber, Donna; Hart, Lesley; Naples, Adam; Chapman, John; Geib, Catherine F; Chart, Hilary; Tan, Mei; Wolhendler, Baruch; Wagner, Richard

    2015-01-01

    The literature has long pointed to heightened frequencies of learning disabilities (LD) within the population of law offenders; however, a systematic appraisal of these observations, careful estimation of these frequencies, and investigation of their correlates and causes have been lacking. Here we present data collected from all youth (1,337 unique admissions, mean age 14.81, 20.3% females) placed in detention in Connecticut (January 1, 2010-July 1, 2011). All youth completed a computerized educational screener designed to test a range of performance in reading (word and text levels) and mathematics. A subsample (n = 410) received the Wide Range Achievement Test, in addition to the educational screener. Quantitative (scale-based) and qualitative (grade-equivalence-based) indicators were then analyzed for both assessments. Results established the range of LD in this sample from 13% to 40%, averaging 24.9%. This work provides a systematic exploration of the type and severity of word and text reading and mathematics skill deficiencies among juvenile detainees and builds the foundation for subsequent efforts that may link these deficiencies to both more formal, structured, and variable definitions and classifications of LD, and to other types of disabilities (e.g., intellectual disability) and developmental disorders (e.g., ADHD) that need to be conducted in future research. PMID:24064502

  10. Microcomputer program optimizes steam systems

    SciTech Connect

    Tsai, T.

    1986-02-24

    A microcomputer program has been developed to determine the steam balance for steam systems in refineries and petrochemical plants. The program provides the optimum design within the constraints of the existing equipment and available economic data. The material balance for steam generation, steam demands, boiler feed water, and demineralized water is calculated. Optimization of the steam system is achieved by the linear programming technique.

  11. Optimal Manipulation of Voting Rules Svetlana Obraztsova

    E-print Network

    Elkind, Edith

    Optimal Manipulation of Voting Rules Svetlana Obraztsova School of Physical and Mathematical of voting manipulation is a prominent research topic in computational social choice. In this paper, we study the com- plexity of optimal manipulation, i.e., finding a manipulative vote that achieves the manipulator

  12. Engineering applications of heuristic multilevel optimization methods

    NASA Technical Reports Server (NTRS)

    Barthelemy, Jean-Francois M.

    1989-01-01

    Some engineering applications of heuristic multilevel optimization methods are presented and the discussion focuses on the dependency matrix that indicates the relationship between problem functions and variables. Coordination of the subproblem optimizations is shown to be typically achieved through the use of exact or approximate sensitivity analysis. Areas for further development are identified.

  13. Engineering applications of heuristic multilevel optimization methods

    NASA Technical Reports Server (NTRS)

    Barthelemy, Jean-Francois M.

    1988-01-01

    Some engineering applications of heuristic multilevel optimization methods are presented and the discussion focuses on the dependency matrix that indicates the relationship between problem functions and variables. Coordination of the subproblem optimizations is shown to be typically achieved through the use of exact or approximate sensitivity analysis. Areas for further development are identified.

  14. Sootblowing optimization for improved boiler performance

    DOEpatents

    James, John Robert; McDermott, John; Piche, Stephen; Pickard, Fred; Parikh, Neel J.

    2012-12-25

    A sootblowing control system that uses predictive models to bridge the gap between sootblower operation and boiler performance goals. The system uses predictive modeling and heuristics (rules) associated with different zones in a boiler to determine an optimal sequence of sootblower operations and achieve boiler performance targets. The system performs the sootblower optimization while observing any operational constraints placed on the sootblowers.

  15. Sootblowing optimization for improved boiler performance

    SciTech Connect

    James, John Robert; McDermott, John; Piche, Stephen; Pickard, Fred; Parikh, Neel J

    2013-07-30

    A sootblowing control system that uses predictive models to bridge the gap between sootblower operation and boiler performance goals. The system uses predictive modeling and heuristics (rules) associated with different zones in a boiler to determine an optimal sequence of sootblower operations and achieve boiler performance targets. The system performs the sootblower optimization while observing any operational constraints placed on the sootblowers.

  16. Surrogate-Based Optimization Using Multifidelity Models with Variable Parameterization and Corrected Space Mapping

    E-print Network

    Peraire, Jaime

    Surrogate-Based Optimization Using Multifidelity Models with Variable Parameterization.2514/1.36043 Surrogate-based-optimization methods provide a means to achieve high-fidelity design optimization at reduced) in a design optimization framework. Surrogate-based optimization (SBO) methods have previously been proposed

  17. Semiconductor Nanowire Growth and Integration

    E-print Network

    Lieber, Charles M.

    , numerous studies have been carried out to explore nanowires as new building blocks in electronics,1 in terms of rate of charging/discharging and stability (e.g., small diameters can better sustain strain and electrodes,38,39,43 all achieved in a single nanowire during growth. Another aspect that sets the "bottom

  18. Distributed Optimization

    NASA Technical Reports Server (NTRS)

    Macready, William; Wolpert, David

    2005-01-01

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

  19. Achieving Maximal Speed of Solution Exchange for Patch Clamp Experiments

    PubMed Central

    Auzmendi, Jerónimo; Fernández Do Porto, Darío; Pallavicini, Carla; Moffatt, Luciano

    2012-01-01

    Background Resolving the kinetics of agonist binding events separately from the subsequent channel gating processes requires the ability of applying and removing the agonist before channel gating occurs. No reported system has yet achieved pulses shorter than 100 µs, necessary to study nicotinic ACh receptor or AMPA receptor activation. Methodology/Principal Findings Solution exchange systems deliver short agonist pulses by moving a sharp interface between a control and an experimental solution across a channel preparation. We achieved shorter pulses by means of an exchange system that combines a faster flow velocity, narrower partition between the two streams, and increased velocity and bandwidth of the movement of the interface. The measured response of the entire system was fed back to optimize the voltage signal applied to the piezoelectric actuator overcoming the spurious oscillations arising from the mechanical resonances when a high bandwidth driving function was applied. Optimization was accomplished by analyzing the transfer function of the solution exchange system. When driven by optimized command pulses the enhanced system provided pulses lasting 26 ± 1 µs and exchanging 93 ± 1% of the solution, as measured in the open tip of a patch pipette. Conclusions/Significance Pulses of this duration open the experimental study of the molecular events that occur between the agonist binding and the opening of the channel. PMID:22879927

  20. Quantum Optimal Control Theory

    E-print Network

    J. Werschnik; E. K. U. Gross

    2007-07-12

    The control of quantum dynamics via specially tailored laser pulses is a long-standing goal in physics and chemistry. Partly, this dream has come true, as sophisticated pulse shaping experiments allow to coherently control product ratios of chemical reactions. The theoretical design of the laser pulse to transfer an initial state to a given final state can be achieved with the help of quantum optimal control theory (QOCT). This tutorial provides an introduction to QOCT. It shows how the control equations defining such an optimal pulse follow from the variation of a properly defined functional. We explain the most successful schemes to solve these control equations and show how to incorporate additional constraints in the pulse design. The algorithms are then applied to simple quantum systems and the obtained pulses are analyzed. Besides the traditional final-time control methods, the tutorial also presents an algorithm and an example to handle time-dependent control targets.

  1. A novel growth strategy and characterization of fully relaxed un-tilted FCC GaAs on Si(1 0 0)

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Partha; Kumar, Rahul; Ghosh, Saptarsi; Chakraborty, Apurba; Bag, Ankush; Kabi, Sanjib; Banerji, Pallab; Biswas, Dhrubes

    2015-05-01

    A novel growth strategy for GaAs epilayer on Si(1 0 0) has been developed with AlAs/GaAs strained layer superlattice to achieve high crystalline quality for device applications. Emphasis has been given on understanding the inconclusive crystalline morphology of the initial layers by comprehensive material characterization. The influence of growth conditions have been studied by varying the growth temperatures, rates and V/III flux ratios. In-situ RHEED observations throughout the growth guided us to recognize the impact of individual growth parameters on the crystalline morphology. All the four stages of growth have been carried out by molecular beam epitaxy. The optimization of growth parameters at every stage initiates the formation of GaAs face centered cubic crystal from the very beginning. Material characterizations include AFM, HRTEM and HRXRD. The latter one, for the first time witnessed the intensity of superlattice satellite peaks in the fourth order. Low values of threading dislocation propagating to the top surface have been seen in HRTEM with absence of anti-phase boundaries (APB). Results for extended dislocations and surface roughness have been observed to be in the order of 106 cm-2 and 2 nm, respectively which is among the best reported values till date. Significant reduction of extended dislocations has been observed under strain fields in the superlattice. Notably, lower alloy mixing due to the optimized growth of AlAs/GaAs resulted in a suitable thermal behavioral platform as required for device applications. Fully relaxed, un-tilted, APB free, single domain and smooth GaAs epilayers have been achieved which paves the pathway to on-wafer integration of high performance III-Arsenide devices with Si logic circuits.

  2. [Assessment of rice achievable productivity and its application in rice production management division: a case study in Fuyang County of Zhejiang Province, East China].

    PubMed

    Wu, Hao-Xiang; Jiang, Yu-Gen; Chen, Jian-Ming; Dai, Yong-Yi; He, Xu-Hua; Qiu, Xi-Ya

    2011-11-01

    Rice productivity is the key factor affecting rice production and its sustainable development. Based on the gradation of cultivated land quality at county-level, this paper evaluated the rice productivity in Fuyang County of Zhejiang Province, and, through selected sampling field investigation and according to the land productivity index of paddy field quality, a model for assessing rice achievable productivity was established, aimed to analyze the regional rice productivity and its achievable productivity. In the study area, there was a positive correlation between the land productivity index and rice yield. For single cropping rice, its achievable productivity was 1.70 x 10(5) t, being 1.6 times of its realistic productivity (1.04 x 10(5) t). In 2009, the realistic rice productivity per unit area was 7676 kg x hm(-2), and the achievable productivity was 8831 kg x hm(-2), with a production potentiality of +15%, a big potential of rice production capacity in the county. Through the analyses of rice productivity, relative superiority of rice production scale, and its growth potential index in the villages and towns, the rice production of Fuyang County was divided into three regions, i. e., key enhancement region, optimization construction region, and development protection region. PMID:22303662

  3. Pattern, Growth and Control

    PubMed Central

    Lander, Arthur D.

    2011-01-01

    The view of biology as goal-directed engineering has deep historical roots in developmental biology, a field currently benefitting from an influx of ideas and methods from systems biology. Systems biology draws on non-biological paradigms to explain developmental mechanisms of control, the specific type of regulation that achieves or maintains a desired end. This review highlights some of the current efforts designed to elucidate basic design principles underlying the engineering objectives of robustness, precision, and scaling that are required during developmental control of growth and pattern formation. Examples from vertebrate and invertebrate development are used to illustrate general principles including the value of integral feedback in achieving set-point control; the usefulness of self-organizing behavior; the importance of recognizing and appropriately handling noise; and the No Free Lunch theory. Through the examination of such principles, systems biology offers a functional framework to make sense of the mechanistic complexity of organismal development. PMID:21414486

  4. Individualism, innovation, and long-run growth

    PubMed Central

    Gorodnichenko, Yuriy; Roland, Gerard

    2011-01-01

    Countries having a more individualist culture have enjoyed higher long-run growth than countries with a more collectivist culture. Individualist culture attaches social status rewards to personal achievements and thus, provides not only monetary incentives for innovation but also social status rewards, leading to higher rates of innovation and economic growth. PMID:22198759

  5. Does Minority Status Increase the Effect of Disability Status on Elementary Schoolchildren's Academic Achievement?

    PubMed Central

    Wu, Qiong; Morgan, Paul L.; Farkas, George

    2015-01-01

    We investigated whether children's reading and mathematics growth trajectories from kindergarten to fifth grade inter-related, and to what extent disability and minority status interacted to predict their achievement trajectories. We conducted secondary data analysis based on a nationally representative sample of 6,446 U.S. schoolchildren from the Early Childhood Longitudinal Study-Kindergarten Cohort. Results indicated that children's reading and mathematics achievement highly correlated in both initial status and growth. Being disabled or a racial/ethnic minority independently predicted lower academic achievement. However, and contrary to what might be expected from prior research on minority children's special education experiences, disability status was associated with similar academic disadvantages for minority students and White students from kindergarten to fifth grade. Growth mixture models identified a group of children with lower and lagging achievement in both reading and mathematics from kindergarten until fifth grade. PMID:26273125

  6. Growth regulation by macrophages

    SciTech Connect

    Wharton, W.; Walker, E.; Stewart, C.C.

    1982-01-01

    The evidence reviewed here indicates that macrophages, either acting alone or in concert with other cells, influence the proliferation of multiple types of cells. Most of the data indicate that these effects are mediated by soluble macrophage-elaborated products (probably proteins) although the role of direct cell-to-cell contacts cannot be ruled out in all cases. A degree of success has been achieved on the biochemical characterization of these factors, due mainly to their low specific activity in conditioned medium and the lack of rapid, specific assays. Understanding the growth-regulating potential of macrophages is an important and needed area of research.

  7. An Analysis of High School Mathematics Achievement and English Language Arts Achievement as Predictors of Science Achievement

    ERIC Educational Resources Information Center

    Edwards, Anthony C.

    2012-01-01

    Science assessments require students to read and comprehend questions and to solve mathematical problems. The purpose of this study is to determine whether the following variables can be used to predict science achievement: English language arts achievement, mathematics achievement, socioeconomic status (SES), limited English proficiency (LEP)…

  8. A Combined Modeling and Experimental Approach for Achieving a Simplified Closed Ecosystem

    NASA Astrophysics Data System (ADS)

    Turc, H. A.; Pintena, J.; Bagarri, P.; Gibiat, F.; Fabreguettes, V.

    1999-01-01

    In CELSS both biological and physico-chemical processes have to be used to support the main needs of the crews and to minimize the re-supply of food and air from Earth. The basic idea is to create a complete food chain (an artificial ecosystem), beginning from the crew, with its wastes, and returning to the crew to supply it with food and air. Two main other steps of this food chain are a waste treatment process and a biomass production including higher plants. We set up the connection of these key modules, which we called ECLAS (Ecosystème Clos Artificiel Simplifié). A growth chamber containing higher plants is connected to a continuous supercritical water oxidation reactor, that converts the harvested biomass into carbon dioxide and enables the photosynthesis of the canopy. To achieve a stable coupling through optimized regulations between the modules, we programmed a modular numerical simulation of the system, in order to assess the involved fluxes and to constrain the last degrees of freedom of the experimental system already built. Simulation results and the first experimental results are here compared.

  9. Optimizing Optimism in Systems Engineers

    E-print Network

    Valerdi, Dr. Ricardo

    2009-11-18

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

  10. Approaches of Russian oil companies to optimal capital structure

    NASA Astrophysics Data System (ADS)

    Ishuk, T.; Ulyanova, O.; Savchitz, V.

    2015-11-01

    Oil companies play a vital role in Russian economy. Demand for hydrocarbon products will be increasing for the nearest decades simultaneously with the population growth and social needs. Change of raw-material orientation of Russian economy and the transition to the innovative way of the development do not exclude the development of oil industry in future. Moreover, society believes that this sector must bring the Russian economy on to the road of innovative development due to neo-industrialization. To achieve this, the government power as well as capital management of companies are required. To make their optimal capital structure, it is necessary to minimize the capital cost, decrease definite risks under existing limits, and maximize profitability. The capital structure analysis of Russian and foreign oil companies shows different approaches, reasons, as well as conditions and, consequently, equity capital and debt capital relationship and their cost, which demands the effective capital management strategy.

  11. Numerical Simulation of Nanostructure Growth

    NASA Technical Reports Server (NTRS)

    Hwang, Helen H.; Bose, Deepak; Govindan, T. R.; Meyyappan, M.

    2004-01-01

    Nanoscale structures, such as nanowires and carbon nanotubes (CNTs), are often grown in gaseous or plasma environments. Successful growth of these structures is defined by achieving a specified crystallinity or chirality, size or diameter, alignment, etc., which in turn depend on gas mixture ratios. pressure, flow rate, substrate temperature, and other operating conditions. To date, there has not been a rigorous growth model that addresses the specific concerns of crystalline nanowire growth, while demonstrating the correct trends of the processing conditions on growth rates. Most crystal growth models are based on the Burton, Cabrera, and Frank (BCF) method, where adatoms are incorporated into a growing crystal at surface steps or spirals. When the supersaturation of the vapor is high, islands nucleate to form steps, and these steps subsequently spread (grow). The overall bulk growth rate is determined by solving for the evolving motion of the steps. Our approach is to use a phase field model to simulate the growth of finite sized nanowire crystals, linking the free energy equation with the diffusion equation of the adatoms. The phase field method solves for an order parameter that defines the evolving steps in a concentration field. This eliminates the need for explicit front tracking/location, or complicated shadowing routines, both of which can be computationally expensive, particularly in higher dimensions. We will present results demonstrating the effect of process conditions, such as substrate temperature, vapor supersaturation, etc. on the evolving morphologies and overall growth rates of the nanostructures.

  12. Enhanced Cellulase Production from Bacillus subtilis by Optimizing Physical Parameters for Bioethanol Production

    PubMed Central

    Deka, Deepmoni; Das, Saprativ P.; Sahoo, Naresh; Das, Debasish; Jawed, Mohammad; Goyal, Dinesh

    2013-01-01

    Effect of physical parameters such as initial pH, agitation (rpm), and temperature (°C) for cellulase production from Bacillus subtilis AS3 was investigated. Central composite design of experiments followed by multiple desirability function was applied for the optimization of cellulase activity and cell growth. The effect of the temperature and agitation was found to be significant among the three independent variables. The optimum levels of initial pH, temperature, and agitation for alkaline carboxymethylcellulase (CMCase) production predicted by the model were 7.2, 39°C, and 121?rpm, respectively. The CMCase activity with unoptimized physical parameters and previously optimized medium composition was 0.43?U/mL. The maximum activity (0.56?U/mL) and cell growth (2.01?mg/mL) predicted by the model were in consensus with values (0.57?U/mL, 2.1?mg/mL) obtained using optimized medium and optimal values of physical parameters. After optimization, 33% enhancement in CMCase activity (0.57?U/mL) was recorded. On scale-up of cellulase production process in bioreactor with all the optimized conditions, an activity of 0.75?U/mL was achieved. Consequently, the bacterial cellulase employed for bioethanol production expending (5%, w/v) NaOH-pretreated wild grass with Zymomonas mobilis yielded an utmost ethanol titre of 7.56?g/L and 11.65?g/L at shake flask and bioreactor level, respectively. PMID:25937985

  13. Achieving diversity in Scotland's forest landscapes

    E-print Network

    Achieving diversity in Scotland's forest landscapes Practice Guide #12;Practice Guide Achieving diversity in Scotland's forest landscapes Alison Grant and Rick Worrell with Scott Wilson, Duncan Ray Grant, landscape architect, with Rick Worrell, forestry consultant, Scott Wilson, consultant forester

  14. Optimization of a thermomagnetic motor

    NASA Astrophysics Data System (ADS)

    Trapanese, Marco; Cipriani, Giovanni; Di Dio, Vincenzo; Franzitta, Vincenzo; Viola, Alessia

    2015-05-01

    In this paper, an approach towards the optimization of the Curie motor is presented. The approach is based on a thermal-magnetic coupled dynamic model of the motor, which is obtained by assuming the use of a ferromagnetic material working at temperatures near the Curie point. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal, and geometrical parameters of the generated torque, is given. The expressions of speed and torque are derived and related to the thermal properties of the machine and are used as optimization indexes in an optimization procedure. The aim of the optimization process is to obtain a machine able to rotate constantly at the maximum achievable power. A design of a machine, based on this theory, is proposed and the related performances are numerically simulated. A preliminary experimental verification of the performances is reported.

  15. Optimal swimming of a sheet

    NASA Astrophysics Data System (ADS)

    Montenegro-Johnson, Thomas D.; Lauga, Eric

    2014-06-01

    Propulsion at microscopic scales is often achieved through propagating traveling waves along hairlike organelles called flagella. Taylor's two-dimensional swimming sheet model is frequently used to provide insight into problems of flagellar propulsion. We derive numerically the large-amplitude wave form of the two-dimensional swimming sheet that yields optimum hydrodynamic efficiency: the ratio of the squared swimming speed to the rate-of-working of the sheet against the fluid. Using the boundary element method, we show that the optimal wave form is a front-back symmetric regularized cusp that is 25% more efficient than the optimal sine wave. This optimal two-dimensional shape is smooth, qualitatively different from the kinked form of Lighthill's optimal three-dimensional flagellum, not predicted by small-amplitude theory, and different from the smooth circular-arc-like shape of active elastic filaments.

  16. Optimal doping control of magnetic semiconductors via subsurfactant epitaxy

    SciTech Connect

    Zeng, Changgan; Zhang, Zhenyu; van Benthem, Klaus; Chisholm, Matthew F; Weitering, Harm H

    2008-02-01

    Dilute magnetic semiconductors (DMS) with high ferromagnetic ordering temperatures (T{sub c}) have vast potential for advancing spin-based electronics or 'spintronics'. To date, achieving high-T{sub c} DMS typically required doping levels of order 5%. Such high doping levels inevitably compromise the structural homogeneity and carrier mobility of the DMS. Here, we establish 'subsurfactant epitaxy' as a novel kinetic pathway for synthesizing Mn-doped germanium with T{sub c} much higher than room temperature, at dramatically reduced doping levels. This is accomplished by optimal control of the diffusion kinetics of the dopant atoms near the growth front in two separate deposition steps. The first involves a submonolayer dose of Mn on Ge(100) at low temperature, which populates subsurface interstitial sites with Mn while suppressing lateral Mn diffusion and clustering. The second step involves epitaxial growth of Ge at elevated temperature, taking advantage of the strong floating ability of the interstitial Mn dopants towards the newly defined subsurface sites at the growth front. Most remarkably, the Mn dopants trapped inside the film are uniformly distributed at substitutional sites, and the resulting film exhibits ferromagnetism above 400 K at the nominal doping level of only 0.2%.

  17. Enriching the Hierarchical Model of Achievement Motivation: Autonomous and Controlling Reasons Underlying Achievement Goals

    ERIC Educational Resources Information Center

    Michou, Aikaterini; Vansteenkiste, Maarten; Mouratidis, Athanasios; Lens, Willy

    2014-01-01

    Background: The hierarchical model of achievement motivation presumes that achievement goals channel the achievement motives of need for achievement and fear of failure towards motivational outcomes. Yet, less is known whether autonomous and controlling reasons underlying the pursuit of achievement goals can serve as additional pathways between…

  18. Achievement Motivation and Self-Attribution Related to School Achievement. Research Projects in Early Childhood Learning.

    ERIC Educational Resources Information Center

    Reed, Linda

    The present study related achievement motivation and the degree of responsibility attributed to the self for success and failure to school achievement. A children's achievement motivation scale and Crandall's Intellectual Achievement Responsibility Questionnaire were administered to elementary school children. Achievers and underachievers were…

  19. Health Risk Behaviors and Academic Achievement

    MedlinePLUS

    Health-Risk Behaviors and Academic Achievement What is the relationship between health-risk behaviors and academic achievement? Data presented below from ... Behavior Survey (YRBS) show a negative association between health-risk behaviors and academic achievement among high school students ...

  20. The Influence of Poverty on Achievement

    ERIC Educational Resources Information Center

    Tienken, Christopher H.

    2012-01-01

    Without a doubt, poverty has a negative influence on student achievement, especially when achievement is measured by state-mandated standardized tests. However, some bureaucrats, such as state commissioners of education and even state governors, continue to downplay the influence of poverty on student achievement. New Jersey's Governor Chris…

  1. Subgroup Achievement and Gap Trends: Vermont, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Vermont for 2010. Vermont's demographic profile is such that achievement trends could only be determined for white, male and female, and low-income student subgroups. In grade 8 (the only grade in which subgroup trends were analyzed by achievement level), the white, low-income,…

  2. Subgroup Achievement and Gap Trends: Wyoming, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Wyoming for 2010. Wyoming's demographic profile is such that achievement trends could only be determined for white, Latino, male and female, and low-income student subgroups. In grade 8 (the only grade in which subgroup trends were analyzed by achievement level), the white,…

  3. The optimal elastic flagellum

    NASA Astrophysics Data System (ADS)

    Spagnolie, Saverio E.; Lauga, Eric

    2010-03-01

    Motile eukaryotic cells propel themselves in viscous fluids by passing waves of bending deformation down their flagella. An infinitely long flagellum achieves a hydrodynamically optimal low-Reynolds number locomotion when the angle between its local tangent and the swimming direction remains constant along its length. Optimal flagella therefore adopt the shape of a helix in three dimensions (smooth) and that of a sawtooth in two dimensions (nonsmooth). Physically, biological organisms (or engineered microswimmers) must expend internal energy in order to produce the waves of deformation responsible for the motion. Here we propose a physically motivated derivation of the optimal flagellum shape. We determine analytically and numerically the shape of the flagellar wave which leads to the fastest swimming for a given appropriately defined energetic expenditure. Our novel approach is to define an energy which includes not only the work against the surrounding fluid, but also (1) the energy stored elastically in the bending of the flagellum, (2) the energy stored elastically in the internal sliding of the polymeric filaments which are responsible for the generation of the bending waves (microtubules), and (3) the viscous dissipation due to the presence of an internal fluid. This approach regularizes the optimal sawtooth shape for two-dimensional deformation at the expense of a small loss in hydrodynamic efficiency. The optimal waveforms of finite-size flagella are shown to depend on a competition between rotational motions and bending costs, and we observe a surprising bias toward half-integer wave numbers. Their final hydrodynamic efficiencies are above 6%, significantly larger than those of swimming cells, therefore indicating available room for further biological tuning.

  4. On the Vacationing CEO Problem: Achievable Rates and Outer Bounds

    E-print Network

    Soundararajan, Rajiv; Vishwanath, Sriram

    2010-01-01

    This paper studies a class of source coding problems that combines elements of the CEO problem with the multiple description problem. In this setting, noisy versions of one remote source are observed by two nodes with encoders (which is similar to the CEO problem). However, it differs from the CEO problem in that each node must generate multiple descriptions of the source. This problem is of interest in multiple scenarios in efficient communication over networks. In this paper, an achievable region and an outer bound are presented for this problem, which is shown to be sum rate optimal for a class of distortion constraints.

  5. Fully Automated Molecular Biology Routines on a Plasmid-Based Functional Proteomic Workcell: Evaluation and Characterization of Yeast Strains Optimized for Growth on Xylose and Engineered to Express an Insecticidal Peptide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optimization of genes important to production of fuel ethanol from hemicellulosic biomass for use in engineering improved commercial yeast strains is necessary to meet the United States' rapidly expanding need for ethanol. United States Department of Agriculture, Agricultural Research Service, Nati...

  6. Optimal design of solidification processes

    NASA Technical Reports Server (NTRS)

    Dantzig, Jonathan A.; Tortorelli, Daniel A.

    1991-01-01

    An optimal design algorithm is presented for the analysis of general solidification processes, and is demonstrated for the growth of GaAs crystals in a Bridgman furnace. The system is optimal in the sense that the prespecified temperature distribution in the solidifying materials is obtained to maximize product quality. The optimization uses traditional numerical programming techniques which require the evaluation of cost and constraint functions and their sensitivities. The finite element method is incorporated to analyze the crystal solidification problem, evaluate the cost and constraint functions, and compute the sensitivities. These techniques are demonstrated in the crystal growth application by determining an optimal furnace wall temperature distribution to obtain the desired temperature profile in the crystal, and hence to maximize the crystal's quality. Several numerical optimization algorithms are studied to determine the proper convergence criteria, effective 1-D search strategies, appropriate forms of the cost and constraint functions, etc. In particular, we incorporate the conjugate gradient and quasi-Newton methods for unconstrained problems. The efficiency and effectiveness of each algorithm is presented in the example problem.

  7. OPTIMAL CONTROL APPLICATIONS AND METHODS Optim. Control Appl. Meth. 2013; 34:680695

    E-print Network

    , Ltd. Received 28 March 2012; Accepted 3 July 2012 KEY WORDS: stem cell tissue engineering; tissue, in the development of tissues from stem cells, the stem cells must uptake growth factors, which are proteins growth or regeneration of a tissue. Four approaches are compared for determining one- dimensional optimal

  8. Framework for computationally efficient optimal irrigation scheduling using ant colony optimization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A general optimization framework is introduced with the overall goal of reducing search space size and increasing the computational efficiency of evolutionary algorithm application for optimal irrigation scheduling. The framework achieves this goal by representing the problem in the form of a decisi...

  9. Optimal shutdown management

    NASA Astrophysics Data System (ADS)

    Bottasso, C. L.; Croce, A.; Riboldi, C. E. D.

    2014-06-01

    The paper presents a novel approach for the synthesis of the open-loop pitch profile during emergency shutdowns. The problem is of interest in the design of wind turbines, as such maneuvers often generate design driving loads on some of the machine components. The pitch profile synthesis is formulated as a constrained optimal control problem, solved numerically using a direct single shooting approach. A cost function expressing a compromise between load reduction and rotor overspeed is minimized with respect to the unknown blade pitch profile. Constraints may include a load reduction not-to-exceed the next dominating loads, a not-to-be-exceeded maximum rotor speed, and a maximum achievable blade pitch rate. Cost function and constraints are computed over a possibly large number of operating conditions, defined so as to cover as well as possible the operating situations encountered in the lifetime of the machine. All such conditions are simulated by using a high-fidelity aeroservoelastic model of the wind turbine, ensuring the accuracy of the evaluation of all relevant parameters. The paper demonstrates the capabilities of the novel proposed formulation, by optimizing the pitch profile of a multi-MW wind turbine. Results show that the procedure can reliably identify optimal pitch profiles that reduce design-driving loads, in a fully automated way.

  10. Are Smart Growth Objectives Complementary or Conflicting?

    NASA Astrophysics Data System (ADS)

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

    2001-05-01

    Increasing awareness about the problems brought on by urban sprawl has 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 seeks to first illuminate that planners, developers, scientists, and environmentalists, among other groups, can consider more than one objective in the context of smart growth. In essence, we posit that smart growth can be construed as a "multiobjective optimization" problem with objectives including: profit maximization, minimization of environmental damage, and maximization of social welfare to name just a few. Unlike single objective optimization, in the multiple objectives case, one seeks to find a "non-inferior" solution such that any improvement in one of the objectives must come at the expense of the other objectives. In essence, such a non-inferior solution gives one possible compromise between the competing objectives. Specific examples of disparate objectives in the context of smart growth might include: a state planner wanting to steer new development towards areas that have available infrastructural capacity to support new growth, to a land developer who might want to build a new sub-division in a specific location and density that will yield the greatest profit. These differing objectives in smart growth if optimized one at a time would undoubtedly lead to different global land use plans for an area. Given the wide range of stakeholders in smart growth, the case of competing objectives is more realistic. This presentation seeks to develop a meaningful framework in which the multiple objectives held by a range of parties might be generally handled in a context that truly reflects smart growth.

  11. Antecedents of students' achievement in statistics

    NASA Astrophysics Data System (ADS)

    Awaludin, Izyan Syazana; Razak, Ruzanna Ab; Harris, Hezlin; Selamat, Zarehan

    2015-02-01

    The applications of statistics in most fields have been vast. Many degree programmes at local universities require students to enroll in at least one statistics course. The standard of these courses varies across different degree programmes. This is because of students' diverse academic backgrounds in which some comes far from the field of statistics. The high failure rate in statistics courses for non-science stream students had been concerning every year. The purpose of this research is to investigate the antecedents of students' achievement in statistics. A total of 272 students participated in the survey. Multiple linear regression was applied to examine the relationship between the factors and achievement. We found that statistics anxiety was a significant predictor of students' achievement. We also found that students' age has significant effect to achievement. Older students are more likely to achieve lowers scores in statistics. Student's level of study also has a significant impact on their achievement in statistics.

  12. A Kinetic and Factorial Approach to Study the Effects of Temperature and Salinity on Growth and Toxin Production by the Dinoflagellate Alexandrium ostenfeldii from the Baltic Sea

    PubMed Central

    Salgado, Pablo; Vázquez, José A.; Riobó, Pilar; Franco, José M.; Figueroa, Rosa I.; Kremp, Anke; Bravo, Isabel

    2015-01-01

    Alexandrium ostenfeldii is present in a wide variety of environments in coastal areas worldwide and is the only dinoflagellate known species that produces paralytic shellfish poisoning (PSP) toxins and two types of cyclic imines, spirolides (SPXs) and gymnodimines (GYMs). The increasing frequency of A. ostenfeldii blooms in the Baltic Sea has been attributed to the warming water in this region. To learn more about the optimal environmental conditions favoring the proliferation of A. ostenfeldii and its complex toxicity, the effects of temperature and salinity on the kinetics of both the growth and the net toxin production of this species were examined using a factorial design and a response-surface analysis (RSA). The results showed that the growth of Baltic A. ostenfeldii occurs over a wide range of temperatures and salinities (12.5–25.5°C and 5–21, respectively), with optimal growth conditions achieved at a temperature of 25.5°C and a salinity of 11.2. Together with the finding that a salinity > 21 was the only growth-limiting factor detected for this strain, this study provides important insights into the autecology and population distribution of this species in the Baltic Sea. The presence of PSP toxins, including gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), and GYMs (GYM-A and GYM-B/-C analogues) was detected under all temperature and salinity conditions tested and in the majority of the cases was concomitant with both the exponential growth and stationary phases of the dinoflagellate’s growth cycle. Toxin concentrations were maximal at temperatures and salinities of 20.9°C and 17 for the GYM-A analogue and > 19°C and 15 for PSP toxins, respectively. The ecological implications of the optimal conditions for growth and toxin production of A. ostenfeldii in the Baltic Sea are discussed. PMID:26636674

  13. An Optimized Mouse Thigh Infection Model for Enterococci and Its Impact on Antimicrobial Pharmacodynamics

    PubMed Central

    Rodriguez, Carlos A.; Agudelo, Maria; Gonzalez, Javier M.; Vesga, Omar

    2014-01-01

    Negligible in vivo growth of enterococci and high-level dispersion of data have led to inaccurate estimations of antibiotic pharmacodynamics (PD). Here we improved an in vivo model apt for PD studies by optimizing the in vitro culture conditions for enterococci. The PD of vancomycin (VAN), ampicillin-sulbactam (SAM), and piperacillin-tazobactam (TZP) against enterococci were determined in vivo, comparing the following different conditions of inoculum preparation: aerobiosis, aerobiosis plus mucin, and anaerobiosis plus mucin. Drug exposure was expressed as the ratio of the area under the concentration-time curve for the free, unbound fraction of the drug to the MIC (fAUC/MIC) (VAN) or the time in a 24-h period that the drug concentration for the free, unbound fraction exceeded the MIC under steady-state pharmacokinetic conditions (fT>MIC) (SAM and TZP) and linked to the change in log10 CFU/thigh. Only anaerobiosis plus mucin enhanced the in vivo growth, yielding significant PD parameters with all antibiotics. In conclusion, robust in vivo growth of enterococci was crucial for better determining the PD of tested antibacterial agents, and this was achieved by optimizing the procedure for preparing the inoculum. PMID:25348523

  14. An optimized mouse thigh infection model for enterococci and its impact on antimicrobial pharmacodynamics.

    PubMed

    Rodriguez, Carlos A; Agudelo, Maria; Gonzalez, Javier M; Vesga, Omar; Zuluaga, Andres F

    2015-01-01

    Negligible in vivo growth of enterococci and high-level dispersion of data have led to inaccurate estimations of antibiotic pharmacodynamics (PD). Here we improved an in vivo model apt for PD studies by optimizing the in vitro culture conditions for enterococci. The PD of vancomycin (VAN), ampicillin-sulbactam (SAM), and piperacillin-tazobactam (TZP) against enterococci were determined in vivo, comparing the following different conditions of inoculum preparation: aerobiosis, aerobiosis plus mucin, and anaerobiosis plus mucin. Drug exposure was expressed as the ratio of the area under the concentration-time curve for the free, unbound fraction of the drug to the MIC (fAUC/MIC) (VAN) or the time in a 24-h period that the drug concentration for the free, unbound fraction exceeded the MIC under steady-state pharmacokinetic conditions (fT(>MIC)) (SAM and TZP) and linked to the change in log10 CFU/thigh. Only anaerobiosis plus mucin enhanced the in vivo growth, yielding significant PD parameters with all antibiotics. In conclusion, robust in vivo growth of enterococci was crucial for better determining the PD of tested antibacterial agents, and this was achieved by optimizing the procedure for preparing the inoculum. PMID:25348523

  15. Thyroid Growth and Cancer.

    PubMed

    Williams, Dillwyn

    2015-09-01

    It is proposed that most papillary thyroid cancers originate in infancy and childhood, based on the early rise in sporadic thyroid carcinoma incidence, the pattern of radiation-induced risk (highest in those exposed as infants), and the high prevalence of sporadic papillary thyroid cancers in children and adolescents (ultrasound screening after the Fukushima accident). The early origin can be linked to the growth pattern of follicular cells, with a high mitotic rate in infancy falling to very low replacement levels in adult life. The cell of origin of thyroid cancers, the differentiated follicular cell, has a limited growth potential. Unlike cancers originating in stem cells, loss of the usually tight link between differentiation and replicative senescence is required for immortalisation. It is suggested that this loss distinguishes larger clinically significant papillary thyroid cancers from micro-papillary thyroid cancers of little clinical significance. Papillary carcinogenesis can then be divided into 3 stages: (1) initiation, the first mutation in the carcinogenic cascade, for radiation-induced papillary thyroid cancers usually a RET rearrangement, (2) progression, acquisition of the additional mutations needed for low-grade malignancy, and (3) escape, further mutations giving immortality and a higher net growth rate. Most papillary thyroid cancers will not have achieved full immortality by adulthood, and remain as so-called micro-carcinomas with a very low growth rate. The use of the term 'cancer' to describe micro-papillary thyroid cancers in older patients encourages overtreatment and alarms patients. Invasive papillary thyroid tumours show a spectrum of malignancy, which at its lowest poses no threat to life. The treatment protocols and nomenclature for small papillary carcinomas need to be reconsidered in the light of the new evidence available, the continuing discovery of smaller lesions, and the model of thyroid carcinogenesis proposed. PMID:26558233

  16. Population growth.

    PubMed

    1984-01-01

    Despite efforts to reduce population growth, the World Bank projects a world population of 10 billion by 2050, with 7 billion living in developing countries. From October 1979 to September 1984, the US Agency for International Development (AID) funded the Research Triangle Institute's (RTI) Integrated Population and Development Planning (IPDP) project to assess rapid population growth effects in 25 developing countries. In October 1984, US AID extended funding for the program, nicknamed INPLAN, for 3 years, at a cost of $6.3 million. Up to 50% of people in developing countries are under age 15, a fact that guarantees large population increases for the next 50-75 years. Also, many regions have been slow to correlate high fertility with socioeconomic development, and in some areas, fertility is actually increasing. INPLAN aims to make governments more aware of population dynamics and to provide training and tools for effective development planning. 40% of INPLAN's work will be done in Africa, 25% in Latin America, and 20% in Asia, with some activity in the Near East. One project in Egypt, involving the use of model generation by microcomputer, was developed by RTI to show rural to urban migration and rapid population growth affects on the educational system. INPLAN expects to develop several other planning sector models on labor force and employment, health and family planning, food supply, housing, and urban development, and apply them to 20-25 countries. Another project provided 9 microcomputer systems and training to Nigerian government agencies. IMPLAN will purchase and distribute 60 such systems in the future. PMID:12314095

  17. [SIAM conference on optimization

    SciTech Connect

    Not Available

    1992-05-10

    Abstracts are presented of 63 papers on the following topics: large-scale optimization, interior-point methods, algorithms for optimization, problems in control, network optimization methods, and parallel algorithms for optimization problems.

  18. Achieving zero stress in iridium, chromium, and nickel thin films

    NASA Astrophysics Data System (ADS)

    Broadway, David M.; Weimer, Jeffrey; Gurgew, Danielle; Lis, Tomasz; Ramsey, Brian D.; O'Dell, Stephen L.; Gubarev, Mikhail; Ames, A.; Bruni, R.

    2015-05-01

    We examine a method for achieving zero intrinsic stress in thin films of iridium, chromium, and nickel deposited by magnetron sputter deposition. The examination of the stress in these materials is motivated by efforts to advance the optical performance of light-weight x-ray space telescopes into the regime of sub-arc second resolution. A characteristic feature of the intrinsic stress behavior in chromium and nickel is their sensitivity to the magnitude and sign of the intrinsic stress with argon gas pressure, including the existence of a critical pressure that results in zero film stress. This critical pressure scales linearly with the film's density. While the effect of stress reversal with argon pressure has been previously reported by Hoffman and others for nickel and chromium, we have discovered a similar behavior for the intrinsic stress in iridium films. Additionally, we have identified zero stress in iridium shortly after island coalescence in the high adatom mobility growth regime. This feature of film growth is used for achieving a total internal stress of -2.89 MPa for a 15.8 nm thick iridium film with a surface roughness of 5.0 +/- 0.5Å based on x-ray reflectivity (XRR) measurement at CuK?. The surface topography was also examined using atomic force microscopy (AFM). The examination of the stress in these films has been performed with a novel in-situ measurement device. The methodology and sensitivity of the in-situ instrument is also described herein.

  19. A Better Way to Motivate Achievement

    ERIC Educational Resources Information Center

    Parker, Dennis

    2012-01-01

    Many low income, minority schools in California are within 100 points of closing the achievement gap, a prize worth working for no matter how inconvenient, uncomfortable, or risky. In this article, the author describes a better way to motivate educators to try new things that will accelerate student learning and close the achievement gap. The…

  20. Achievement and Its Correlates: Symposium III A.

    ERIC Educational Resources Information Center

    Ismail, Maznah; And Others

    This symposium contains a report of a study which (1) examined the relationship between Malaysian children's perception of control and their academic achievement, by Maznah Ismail and Choo Piang Foong, and two abstracts of studies which (2) investigated achievement motivation and attribution of success in rural and urban Malaysian ethnic groups,…

  1. Personality, Approaches to Learning and Achievement

    ERIC Educational Resources Information Center

    Swanberg, Anne Berit; Martinsen, Oyvind Lund

    2010-01-01

    The present study investigated the relationships between the five-factor model of personality, approaches to learning and academic achievement. Based on the previous research, we expected approaches to have a mediating effect between personality and academic achievement. Six hundred and eighty-seven business students participated in a survey; 56%…

  2. Psychological Adjustment and Academic Achievement among Adolescents

    ERIC Educational Resources Information Center

    Mahmood, Khalid; Iqbal, Muhammad Maqsood

    2015-01-01

    This study was studied that emotional and behavioural problems of young students who are directly related to their academic achievement and thus play a vital role in the development of young learners carrier. This study helped to fill a gap by conducting an exploration of psychological adjustment and academic achievement among adolescents. It also…

  3. Achievement Goal Orientations and Identity Formation Styles

    ERIC Educational Resources Information Center

    Kaplan, Avi; Flum, Hanoch

    2010-01-01

    The present article points to shared underlying theoretical assumptions and central processes of a prominent academic motivation perspective--achievement goal theory--and recent process perspectives in the identity formation literature, and more specifically, identity formation styles. The review highlights the shared definition of achievement

  4. The Black-White Achievement Gap Revisited

    ERIC Educational Resources Information Center

    Braun, Henry; Chapman, Lauren; Vezzu, Sailesh

    2010-01-01

    This study examines trends in Black student achievement and in the Black-White achievement gap over the period 2000 to 2007, employing data from ten states drawn from the NAEP Grade 8 mathematics assessments. Results are obtained for three levels of aggregation: the state, school poverty stratum within the state, and schools within poverty…

  5. Gifted Student Academic Achievement and Program Quality

    ERIC Educational Resources Information Center

    Jordan, Katrina Ann Woolsey

    2010-01-01

    Gifted academic achievement has been identified as a major area of interest for educational researchers. The purpose of this study was to ascertain whether there was a relation between the quality of gifted programs as perceived by teachers, coordinators and supervisors of the gifted and the achievement of the same gifted students in 6th and 7th…

  6. Variability of Pupil Achievement in Mathematics.

    ERIC Educational Resources Information Center

    Bolvin, John O.

    Reported is a study in the Oakleaf Elementary School to test the hypothesis that variability of achievement within a particular grade approximates the number of years the pupils have been in school (e.g., in the third grade, a spread of three years is expected). Data were collected and analyzed regarding range of achievement prior to instruction…

  7. Brain Wave Analysis and School Achievement.

    ERIC Educational Resources Information Center

    Wilson, Barry; And Others

    The Brain Wave Analyzer (BWA Ertl 02) was used to measure the brain potentials of 110 public school children. Resulting scores were correlated with concurrent measures of school achievement. Results indicate that certain brain wave scores have relatively low correlations with school achievement compared to traditional intelligence measures but may…

  8. Attitudes and Achievement of Bruneian Science Students.

    ERIC Educational Resources Information Center

    Dhindsa, Harkirat S.; Chung, Gilbert

    2003-01-01

    Evaluates attitudes towards and achievement in science of Form 3 students studying in single-sex and coeducational schools in Brunei. Results demonstrated significant differences in attitudes towards and achievement in science of male and female students in single-sex schools and students in coeducational schools. (Contains 46 references.)…

  9. Debating Values: Race, Class and Academic Achievement

    ERIC Educational Resources Information Center

    Milton, Penny

    2008-01-01

    The relationships among race, class and academic achievement are complex, yet have been well documented in Canada for the last thirty years. Generations of students have experienced them--lowered expectations for achievement, gross generalizations about parents' backgrounds and aspirations, negative stereotypes of communities, and curricula that…

  10. Subgroup Achievement and Gap Trends: Utah, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Utah for 2010. Utah implemented new standards and cut scores in math so trend data that include 2009 are not available. In grade 8 (the only grade in which subgroup trends were analyzed by achievement level), Utah showed across-the-board gains in reading at the basic,…

  11. Association between Emotional Variables and School Achievement

    ERIC Educational Resources Information Center

    Randler, Christoph

    2009-01-01

    Recent psychological studies highlight emotional aspects, and they show an important role within individual learning processes. Hereby, positive emotions were supposed to positively influence learning and achievement processes and negative ones do the contrary. In this study, an educational unit "ecosystem lake" was used during which achievement

  12. The Constraints of Poverty on High Achievement

    ERIC Educational Resources Information Center

    Burney, Virginia H.; Beilke, Jayne R.

    2008-01-01

    Research studies on school success often focus on the impact of discrete elements such as race, culture, ethnicity, gender, language, or school location on high achievement. The condition of poverty, however, may be the most important of all student differences in relation to high achievement; although not all schools have racial diversity, nearly…

  13. Regulatory Contributors to Children's Kindergarten Achievement.

    ERIC Educational Resources Information Center

    Howse, Robin B.; Calkins, Susan D.; Anastopoulos, Arthur D.; Keane, Susan P.; Shelton, Terri L.

    2003-01-01

    This study examined whether preschoolers' emotion regulation, problem behavior, and kindergarten behavioral self-regulation in the classroom predicted kindergarten achievement scores. Findings indicated that children's emotion regulation and behavioral self-regulation in the classroom were related to all achievement measures. Relation between…

  14. Effects of Weight on Children's Educational Achievement

    ERIC Educational Resources Information Center

    Kaestner, Robert; Grossman, Michael

    2009-01-01

    In this paper, we investigate the association between weight and children's educational achievement, as measured by scores on Peabody Individual Achievement Tests in math and reading, and grade attainment. Data for the study came from the 1979 cohort of the National Longitudinal Survey of Youth (NLSY), which contains a large, national sample of…

  15. Youth Perspectives of Achievement: Is Money Everything?

    ERIC Educational Resources Information Center

    Matope, Jasmine; Badroodien, Azeem

    2015-01-01

    This article draws from a qualitative research project completed at Victoria High School (pseudonym) in Cape Town in 2012 which explored 13 learners' perspectives of achievement and its influence on their lives and thinking. The piece problematises and analyses taken-for-granted connections between money, achievement, youth aspirations and views…

  16. Professional Learning Communities Impact on Student Achievement

    ERIC Educational Resources Information Center

    Hamilton, Jan L.

    2013-01-01

    This study examined the impact of the Professional Learning Community model on student achievement in the state of California. Specifically, the study compared student achievement between two school types: Professional Learning Community schools and Non Professional Learning schools. The research utilized existing API scores for California schools…

  17. Will Flexible Learning Raise Student Achievement?

    ERIC Educational Resources Information Center

    Guest, Ross

    2005-01-01

    This paper presents both theoretical and survey evidence on the effect of flexible learning--in particular, the shift to a more student-centred approach to learning--on academic achievement by students. A survey was conducted of 577 business students at a major Australian university in order to elicit their preferences for academic achievement and…

  18. Subgroup Achievement and Gap Trends: Nevada, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Nevada for 2010. In grade 8 (the only grade in which subgroup trends were analyzed by achievement level), Nevada showed across-the-board gains--improvements in both reading and math at the basic, proficient and advanced levels for all racial/ethnic subgroups, low income…

  19. Multimedia Technology and Students' Achievement in Geography

    ERIC Educational Resources Information Center

    DaSilva, Edmar Bernardes; Kvasnak, Robb Neil

    2012-01-01

    In this study done at a community college in South Florida, the achievements of students who spoke English as their second language who had attended their K-12 education outside the United States in their home countries, in a U.S. college course on world geography are compared with the achievements of students in the same classes who spoke English…

  20. The Achiever. Volume 6, Number 7

    ERIC Educational Resources Information Center

    Ashby, Nicole, Ed.

    2007-01-01

    "The Achiever" is a monthly publication for parents and community leaders from the Office of Communications and Outreach, U.S. Department of Education. This issue contains the following articles: (1) President Seeks to Build on Law's Results; (2) Bridging the Gap: Ohio Charter School Surmounts Age, Achievement Barriers; (3) Spellings'…