Novel in vitro and mathematical models for the prediction of chemical toxicity.

PubMed

Williams, Dominic P; Shipley, Rebecca; Ellis, Marianne J; Webb, Steve; Ward, John; Gardner, Iain; Creton, Stuart

2013-01-01

The focus of much scientific and medical research is directed towards understanding the disease process and defining therapeutic intervention strategies. The scientific basis of drug safety is very complex and currently remains poorly understood, despite the fact that adverse drug reactions (ADRs) are a major health concern and a serious impediment to development of new medicines. Toxicity issues account for ∼21% drug attrition during drug development and safety testing strategies require considerable animal use. Mechanistic relationships between drug plasma levels and molecular/cellular events that culminate in whole organ toxicity underpins development of novel safety assessment strategies. Current in vitro test systems are poorly predictive of toxicity of chemicals entering the systemic circulation, particularly to the liver. Such systems fall short because of (1) the physiological gap between cells currently used and human hepatocytes existing in their native state, (2) the lack of physiological integration with other cells/systems within organs, required to amplify the initial toxicological lesion into overt toxicity, (3) the inability to assess how low level cell damage induced by chemicals may develop into overt organ toxicity in a minority of patients, (4) lack of consideration of systemic effects. Reproduction of centrilobular and periportal hepatocyte phenotypes in in vitro culture is crucial for sensitive detection of cellular stress. Hepatocyte metabolism/phenotype is dependent on cell position along the liver lobule, with corresponding differences in exposure to substrate, oxygen and hormone gradients. Application of bioartificial liver (BAL) technology can encompass in vitro predictive toxicity testing with enhanced sensitivity and improved mechanistic understanding. Combining this technology with mechanistic mathematical models describing intracellular metabolism, fluid-flow, substrate, hormone and nutrient distribution provides the opportunity to

Novel in vitro and mathematical models for the prediction of chemical toxicity

PubMed Central

Shipley, Rebecca; Ellis, Marianne J.; Webb, Steve; Ward, John; Gardner, Iain; Creton, Stuart

2013-01-01

The focus of much scientific and medical research is directed towards understanding the disease process and defining therapeutic intervention strategies. The scientific basis of drug safety is very complex and currently remains poorly understood, despite the fact that adverse drug reactions (ADRs) are a major health concern and a serious impediment to development of new medicines. Toxicity issues account for ∼21% drug attrition during drug development and safety testing strategies require considerable animal use. Mechanistic relationships between drug plasma levels and molecular/cellular events that culminate in whole organ toxicity underpins development of novel safety assessment strategies. Current in vitro test systems are poorly predictive of toxicity of chemicals entering the systemic circulation, particularly to the liver. Such systems fall short because of (1) the physiological gap between cells currently used and human hepatocytes existing in their native state, (2) the lack of physiological integration with other cells/systems within organs, required to amplify the initial toxicological lesion into overt toxicity, (3) the inability to assess how low level cell damage induced by chemicals may develop into overt organ toxicity in a minority of patients, (4) lack of consideration of systemic effects. Reproduction of centrilobular and periportal hepatocyte phenotypes in in vitro culture is crucial for sensitive detection of cellular stress. Hepatocyte metabolism/phenotype is dependent on cell position along the liver lobule, with corresponding differences in exposure to substrate, oxygen and hormone gradients. Application of bioartificial liver (BAL) technology can encompass in vitro predictive toxicity testing with enhanced sensitivity and improved mechanistic understanding. Combining this technology with mechanistic mathematical models describing intracellular metabolism, fluid-flow, substrate, hormone and nutrient distribution provides the opportunity to

Reducing chemical exposures at home: opportunities for action

PubMed Central

Zota, Ami R; Singla, Veena; Adamkiewicz, Gary; Mitro, Susanna D; Dodson, Robin E

2017-01-01

Indoor environments can influence human environmental chemical exposures and, ultimately, public health. Furniture, electronics, personal care and cleaning products, floor coverings and other consumer products contain chemicals that can end up in the indoor air and settled dust. Consumer product chemicals such as phthalates, phenols, flame retardants and per- and polyfluorinated alkyl substances are widely detected in the US general population, including vulnerable populations, and are associated with adverse health effects such as reproductive and endocrine toxicity. We discuss the implications of our recent meta-analysis describing the patterns of chemical exposures and the ubiquity of multiple chemicals in indoor environments. To reduce the likelihood of exposures to these toxic chemicals, we then discuss approaches for exposure mitigation: targeting individual behaviour change, household maintenance and purchasing decisions, consumer advocacy and corporate responsibility in consumer markets, and regulatory action via state/federal policies. There is a need to further develop evidence-based strategies for chemical exposure reduction in each of these areas, given the multi-factorial nature of the problem. Further identifying those at greatest risk; understanding the individual, household and community factors that influence indoor chemical exposures; and developing options for mitigation may substantially improve individuals’ exposures and health. PMID:28756396

Reducible or irreducible? Mathematical reasoning and the ontological method.

PubMed

Fisher, William P

2010-01-01

Science is often described as nothing but the practice of measurement. This perspective follows from longstanding respect for the roles mathematics and quantification have played as media through which alternative hypotheses are evaluated and experience becomes better managed. Many figures in the history of science and psychology have contributed to what has been called the "quantitative imperative," the demand that fields of study employ number and mathematics even when they do not constitute the language in which investigators think together. But what makes an area of study scientific is, of course, not the mere use of number, but communities of investigators who share common mathematical languages for exchanging quantitative and quantitative value. Such languages require rigorous theoretical underpinning, a basis in data sufficient to the task, and instruments traceable to reference standard quantitative metrics. The values shared and exchanged by such communities typically involve the application of mathematical models that specify the sufficient and invariant relationships necessary for rigorous theorizing and instrument equating. The mathematical metaphysics of science are explored with the aim of connecting principles of quantitative measurement with the structures of sufficient reason.

Mathematical Modeling to Reduce Waste of Compounded Sterile Products in Hospital Pharmacies

PubMed Central

Dobson, Gregory; Haas, Curtis E.; Tilson, David

2014-01-01

Abstract In recent years, many US hospitals embarked on “lean” projects to reduce waste. One advantage of the lean operational improvement methodology is that it relies on process observation by those engaged in the work and requires relatively little data. However, the thoughtful analysis of the data captured by operational systems allows the modeling of many potential process options. Such models permit the evaluation of likely waste reductions and financial savings before actual process changes are made. Thus the most promising options can be identified prospectively, change efforts targeted accordingly, and realistic targets set. This article provides one example of such a datadriven process redesign project focusing on waste reduction in an in-hospital pharmacy. A mathematical model of the medication prepared and delivered by the pharmacy is used to estimate the savings from several potential redesign options (rescheduling the start of production, scheduling multiple batches, or reordering production within a batch) as well as the impact of information system enhancements. The key finding is that mathematical modeling can indeed be a useful tool. In one hospital setting, it estimated that waste could be realistically reduced by around 50% by using several process changes and that the greatest benefit would be gained by rescheduling the start of production (for a single batch) away from the period when most order cancellations are made. PMID:25477580

Hazardous Chemicals on the Job: A Workers Guide to Reducing Exposure.

ERIC Educational Resources Information Center

Conrad, Fran; Kayman, Lindsey

This guide is intended to assist workers in reducing their exposure to hazardous chemicals on the job. It describes a systematic preventive approach to hazardous chemicals that is based on the following steps: determining which chemicals are in use at a particular worksite (techniques for asking the company and steps to take if the company is…

Perceptions of College Students on Successful Strategies for Reducing Mathematics Anxiety

ERIC Educational Resources Information Center

Allen, Amelia Ann

2011-01-01

Despite more than 50 years of attempts to improve mathematics education and the simultaneous prevalence of fears associated with learning mathematics in the United States, the problem of mathematics anxiety among students still remains. This qualitative phenomenological study was focused on understanding college students' perceptions regarding the…

Exploring Effects of High School Students' Mathematical Processing Skills and Conceptual Understanding of Chemical Concepts on Algorithmic Problem Solving

ERIC Educational Resources Information Center

Gultepe, Nejla; Yalcin Celik, Ayse; Kilic, Ziya

2013-01-01

The purpose of the study was to examine the effects of students' conceptual understanding of chemical concepts and mathematical processing skills on algorithmic problem-solving skills. The sample (N = 554) included grades 9, 10, and 11 students in Turkey. Data were collected using the instrument "MPC Test" and with interviews. The MPC…

Mathematics Models in Chemistry--An Innovation for Non-Mathematics and Non-Science Majors

ERIC Educational Resources Information Center

Rash, Agnes M.; Zurbach, E. Peter

2004-01-01

The intention of this article is to present a year-long interdisciplinary course, Mathematical Models in Chemistry. The course is comprised of eleven units, each of which has both a mathematical and a chemical component. A syllabus of the course is given and the format of the class is explained. The interaction of the professors and the content is…

Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite.

PubMed

Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D; Pumera, Martin

2012-08-07

Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research.

Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite

PubMed Central

Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D.; Pumera, Martin

2012-01-01

Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research. PMID:22826262

Converting STEM Doctoral Dissertations into Patent Applications: A Study of Chemistry, Physics, Mathematics, and Chemical Engineering Dissertations from CIC Institutions

ERIC Educational Resources Information Center

Butkovich, Nancy J.

2015-01-01

Doctoral candidates may request short-term embargoes on the release of their dissertations in order to apply for patents. This study examines how often inventions described in dissertations in chemical engineering, chemistry, physics, and mathematics are converted into U.S. patent applications, as well as the relationship between dissertation…

Computer program determines chemical composition of physical system at equilibrium

NASA Technical Reports Server (NTRS)

Kwong, S. S.

1966-01-01

FORTRAN 4 digital computer program calculates equilibrium composition of complex, multiphase chemical systems. This is a free energy minimization method with solution of the problem reduced to mathematical operations, without concern for the chemistry involved. Also certain thermodynamic properties are determined as byproducts of the main calculations.

Chemical treatment costs reduced with in-pond raceway systems

USDA-ARS?s Scientific Manuscript database

Production systems such as in-pond raceway systems (IPRS) and split ponds are providing an alternative to traditional pond culture for raising catfish in several southeastern states. One advantage noted by farmers utilizing these systems is the reduced cost associated with the chemical treatment of ...

Investigation of the Effects of Mathematical Thinking States of Form Teachers on Their Mathematics Teaching Anxieties

ERIC Educational Resources Information Center

Yorulmaz, Alper; Altintas, Sedat; Sidekli, Sabri

2017-01-01

The state of mathematical thinking is considered to have an effect on the formation of anxiety regarding teaching mathematics. It is hypothesized that with the formation of mathematical thinking, the anxiety in teachers regarding teaching mathematics will be reduced. Since mathematical thinking is a skill acquired starting from the early years of…

Drude conductivity exhibited by chemically synthesized reduced graphene oxide

NASA Astrophysics Data System (ADS)

Younas, Daniyal; Javed, Qurat-ul-Ain; Fatima, Sabeen; Kalsoom, Riffat; Abbas, Hussain; Khan, Yaqoob

2017-09-01

Electrical conductance in graphene layers having Drude like response due to massless Dirac fermions have been well explained theoretically as well as experimentally. In this paper Drude like electrical conductivity response of reduced graphene oxide synthesized by chemical route is presented. A method slightly different from conventional methods is used to synthesize graphene oxide which is then converted to reduced graphene oxide. Various analytic techniques were employed to verify the successful oxidation and reductions in the process and were also used to measure various parameters like thickness of layers and conductivity. Obtained reduced graphene oxide has very thin layers of thickness around 13 nm on average and reduced graphene oxide has average thickness below 20 nm. Conductivity of the reduced graphene was observed to have Drude like response which is explained on basis of Drude model for conductors.

Mathematical anxiety is linked to reduced cognitive reflection: a potential road from discomfort in the mathematics classroom to susceptibility to biases

PubMed Central

2014-01-01

Background When asked to solve mathematical problems, some people experience anxiety and threat, which can lead to impaired mathematical performance (Curr Dir Psychol Sci 11:181–185, 2002). The present studies investigated the link between mathematical anxiety and performance on the cognitive reflection test (CRT; J Econ Perspect 19:25–42, 2005). The CRT is a measure of a person’s ability to resist intuitive response tendencies, and it correlates strongly with important real-life outcomes, such as time preferences, risk-taking, and rational thinking. Methods In Experiments 1 and 2 the relationships between maths anxiety, mathematical knowledge/mathematical achievement, test anxiety and cognitive reflection were analysed using mediation analyses. Experiment 3 included a manipulation of working memory load. The effects of anxiety and working memory load were analysed using ANOVAs. Results Our experiments with university students (Experiments 1 and 3) and secondary school students (Experiment 2) demonstrated that mathematical anxiety was a significant predictor of cognitive reflection, even after controlling for the effects of general mathematical knowledge (in Experiment 1), school mathematical achievement (in Experiment 2) and test anxiety (in Experiments 1–3). Furthermore, Experiment 3 showed that mathematical anxiety and burdening working memory resources with a secondary task had similar effects on cognitive reflection. Conclusions Given earlier findings that showed a close link between cognitive reflection, unbiased decisions and rationality, our results suggest that mathematical anxiety might be negatively related to individuals’ ability to make advantageous choices and good decisions. PMID:25179230

Mathematical anxiety is linked to reduced cognitive reflection: a potential road from discomfort in the mathematics classroom to susceptibility to biases.

PubMed

Morsanyi, Kinga; Busdraghi, Chiara; Primi, Caterina

2014-09-01

When asked to solve mathematical problems, some people experience anxiety and threat, which can lead to impaired mathematical performance (Curr Dir Psychol Sci 11:181-185, 2002). The present studies investigated the link between mathematical anxiety and performance on the cognitive reflection test (CRT; J Econ Perspect 19:25-42, 2005). The CRT is a measure of a person's ability to resist intuitive response tendencies, and it correlates strongly with important real-life outcomes, such as time preferences, risk-taking, and rational thinking. In Experiments 1 and 2 the relationships between maths anxiety, mathematical knowledge/mathematical achievement, test anxiety and cognitive reflection were analysed using mediation analyses. Experiment 3 included a manipulation of working memory load. The effects of anxiety and working memory load were analysed using ANOVAs. Our experiments with university students (Experiments 1 and 3) and secondary school students (Experiment 2) demonstrated that mathematical anxiety was a significant predictor of cognitive reflection, even after controlling for the effects of general mathematical knowledge (in Experiment 1), school mathematical achievement (in Experiment 2) and test anxiety (in Experiments 1-3). Furthermore, Experiment 3 showed that mathematical anxiety and burdening working memory resources with a secondary task had similar effects on cognitive reflection. Given earlier findings that showed a close link between cognitive reflection, unbiased decisions and rationality, our results suggest that mathematical anxiety might be negatively related to individuals' ability to make advantageous choices and good decisions.

Mathematical challenges from theoretical/computational chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-12-31

The committee believes that this report has relevance and potentially valuable suggestions for a wide range of readers. Target audiences include: graduate departments in the mathematical and chemical sciences; federal and private agencies that fund research in the mathematical and chemical sciences; selected industrial and government research and development laboratories; developers of software and hardware for computational chemistry; and selected individual researchers. Chapter 2 of this report covers some history of computational chemistry for the nonspecialist, while Chapter 3 illustrates the fruits of some past successful cross-fertilization between mathematical scientists and computational/theoretical chemists. In Chapter 4 the committee has assembledmore » a representative, but not exhaustive, survey of research opportunities. Most of these are descriptions of important open problems in computational/theoretical chemistry that could gain much from the efforts of innovative mathematical scientists, written so as to be accessible introductions to the nonspecialist. Chapter 5 is an assessment, necessarily subjective, of cultural differences that must be overcome if collaborative work is to be encouraged between the mathematical and the chemical communities. Finally, the report ends with a brief list of conclusions and recommendations that, if followed, could promote accelerated progress at this interface. Recognizing that bothersome language issues can inhibit prospects for collaborative research at the interface between distinctive disciplines, the committee has attempted throughout to maintain an accessible style, in part by using illustrative boxes, and has included at the end of the report a glossary of technical terms that may be familiar to only a subset of the target audiences listed above.« less

Using Propensity Scores to Reduce Selection Bias in Mathematics Education Research

ERIC Educational Resources Information Center

Graham, Suzanne E.

2010-01-01

Selection bias is a problem for mathematics education researchers interested in using observational rather than experimental data to make causal inferences about the effects of different instructional methods in mathematics on student outcomes. Propensity score methods represent 1 approach to dealing with such selection bias. This article…

Mathematical Modeling of Multiphase Filtration in Porous Media with a Chemically Active Skeleton

NASA Astrophysics Data System (ADS)

Khramchenkov, M. G.; Khramchenkov, É. M.

2018-01-01

The authors propose a mathematical model of two-phase filtration that occurs under the conditions of dissolution of a porous medium. The model can be used for joint description of complex chemical-hydrogeomechanical processes that are of frequent occurrence in the oil-and-gas producing and nature conservation practice. As an example, consideration is given to the acidizing of the bottom zone of the injection well of an oil reservoir. Enclosing rocks are represented by carbonates. The phases of the process are an aqueous solution of hydrochloric acid and oil. A software product for computational experiments is developed. For the numerical experiments, use is made of the data on the wells of an actual oil field. Good agreement is obtained between the field data and the calculated data. Numerical experiments with different configurations of the permeability of an oil stratum are conducted.

Mathematical modeling of chemical composition modification and etching of polymers under the atomic oxygen influence

NASA Astrophysics Data System (ADS)

Chirskaia, Natalia; Novikov, Lev; Voronina, Ekaterina

2016-07-01

Atomic oxygen (AO) of the upper atmosphere is one of the most important space factors that can cause degradation of spacecraft surface. In our previous mathematical model the Monte Carlo method and the "large particles" approximation were used for simulating processes of polymer etching under the influence of AO [1]. The interaction of enlarged AO particles with the polymer was described in terms of probabilities of reactions such as etching of polymer and specular and diffuse scattering of the AO particles on polymer. The effects of atomic oxygen on protected polymers and microfiller containing composites were simulated. The simulation results were in quite good agreement with the results of laboratory experiments on magnetoplasmadynamic accelerator of the oxygen plasma of SINP MSU [2]. In this paper we present a new model that describes the reactions of AO interactions with polymeric materials in more detail. Reactions of formation and further emission of chemical compounds such as CO, CO _{2}, H _{2}O, etc. cause the modification of the chemical composition of the polymer and change the probabilities of its consequent interaction with the AO. The simulation results are compared with the results of previous simulation and with the results of laboratory experiments. The reasons for the differences between the results of natural experiments on spacecraft, laboratory experiments and simulations are discussed. N. Chirskaya, M. Samokhina, Computer modeling of polymer structures degradation under the atomic oxygen exposure, WDS'12 Proceedings of Contributed Papers: Part III - Physics, Matfyzpress Prague, 2012, pp. 30-35. E. Voronina, L. Novikov, V. Chernik, N. Chirskaya, K. Vernigorov, G. Bondarenko, and A. Gaidar, Mathematical and experimental simulation of impact of atomic oxygen of the earth's upper atmosphere on nanostructures and polymer composites, Inorganic Materials: Applied Research, 2012, vol. 3, no. 2, pp. 95-101.

Evaluation of chemical immersion treatments to reduce microbial populations in fresh beef.

PubMed

Kassem, Ahmed; Meade, Joseph; Gibbons, James; McGill, Kevina; Walsh, Ciara; Lyng, James; Whyte, Paul

2017-11-16

The aim of the current study was to assess the ability of a number of chemicals (acetic Acid (AA), citric acid (CA) lactic acid (LA), sodium decanoate (SD) and trisodium phosphate (TSP)) to reduce microbial populations (total viable count, Campylobacter jejuni, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes) on raw beef using an immersion system. The following concentrations of each chemical were used: 3 & 5% for AA, CA, LA, SD and 10 &12% for TSP. Possible synergistic effects of using combinations of two chemicals sequentially (LA+CA and LA+AA) were also investigated. L*, a* and b* values were measured before and after treatments and ΔE* values were calculated in order to determine any changes in the color of meat due to the use of these chemicals. In general, all chemical treatments resulted in significantly (p<0.05) reduced bacterial counts when compared to untreated controls. The greatest reductions were obtained by using LA3%, SD5%, AA5%, LA5% and SD3% for TVC, C. jejuni, E. coli, S. typhimurium and L. monocytogenes, respectively. However, no significant difference in microbial load was observed between the different concentrations of each chemical used (p>0.05). The application of combinations of chemical immersion treatments (LA3%+AA3% and LA3%+CA3%) did not result in further significant reductions in microbial populations when compared to single chemical treatments (P<0.05). Assessment of color changes in meat following the application of chemical immersion treatments indicated that using AA or CA at either concentration and LA at 5% led to an increase in the ΔE* value of >3 immediately after treatment and after 24h storage. The remaining treatments did not result in significant changes to the color of raw beef. Copyright © 2017 Elsevier B.V. All rights reserved.

High-Quality Reduced Graphene Oxide by a Dual-Function Chemical Reduction and Healing Process

PubMed Central

Some, Surajit; Kim, Youngmin; Yoon, Yeoheung; Yoo, HeeJoun; Lee, Saemi; Park, Younghun; Lee, Hyoyoung

2013-01-01

A new chemical dual-functional reducing agent, thiophene, was used to produce high-quality reduced graphene oxide (rGO) as a result of a chemical reduction of graphene oxide (GO) and the healing of rGO. Thiophene reduced GO by donation of electrons with acceptance of oxygen while it was converted into an intermediate oxidised polymerised thiophene that was eventually transformed into polyhydrocarbon by loss of sulphur atoms. Surprisingly, the polyhydrocarbon template helped to produce good-quality rGOC (chemically reduced) and high-quality rGOCT after thermal treatment. The resulting rGOCT nanosheets did not contain any nitrogen or sulphur impurities, were highly deoxygenated and showed a healing effect. Thus the electrical properties of the as-prepared rGOCT were superior to those of conventional hydrazine-produced rGO that require harsh reaction conditions. Our novel dual reduction and healing method with thiophene could potentially save energy and facilitate the commercial mass production of high-quality graphene. PMID:23722643

Chemically active reduced graphene oxide with tunable C/O ratios.

PubMed

Compton, Owen C; Jain, Bonny; Dikin, Dmitriy A; Abouimrane, Ali; Amine, Khalil; Nguyen, Sonbinh T

2011-06-28

Organic dispersions of graphene oxide can be thermally reduced in polar organic solvents under reflux conditions to afford electrically conductive, chemically active reduced graphene oxide (CARGO) with tunable C/O ratios, dependent on the boiling point of the solvent. The reductions are achieved after only 1 h of reflux, and the corresponding C/O ratios do not change upon further thermal treatment. Hydroxyl and carboxyl groups can be removed when the reflux is carried out above 155 °C, while epoxides are removable only when the temperature is higher than 200 °C. The increasing hydrophobic nature of CARGO, as its C/O ratio increases, improves the dispersibility of the nanosheets in a polystyrene matrix, in contrast to the aggregates formed with CARGO having lower C/O ratios. The excellent processability of the obtained CARGO dispersions is demonstrated via free-standing CARGO papers that exhibit tunable electrical conductivity/chemical activity and can be used as lithium-ion battery anodes with enhanced Coulombic efficiency.

Mathematical Modeling of Dual Layer Shell Type Recuperation System for Biogas Dehumidification

NASA Astrophysics Data System (ADS)

Gendelis, S.; Timuhins, A.; Laizans, A.; Bandeniece, L.

2015-12-01

The main aim of the current paper is to create a mathematical model for dual layer shell type recuperation system, which allows reducing the heat losses from the biomass digester and water amount in the biogas without any additional mechanical or chemical components. The idea of this system is to reduce the temperature of the outflowing gas by creating two-layered counter-flow heat exchanger around the walls of biogas digester, thus increasing a thermal resistance and the gas temperature, resulting in a condensation on a colder surface. Complex mathematical model, including surface condensation, is developed for this type of biogas dehumidifier and the parameter study is carried out for a wide range of parameters. The model is reduced to 1D case to make numerical calculations faster. It is shown that latent heat of condensation is very important for the total heat balance and the condensation rate is highly dependent on insulation between layers and outside temperature. Modelling results allow finding optimal geometrical parameters for the known gas flow and predicting the condensation rate for different system setups and seasons.

Current problems in applied mathematics and mathematical physics

NASA Astrophysics Data System (ADS)

Samarskii, A. A.

Papers are presented on such topics as mathematical models in immunology, mathematical problems of medical computer tomography, classical orthogonal polynomials depending on a discrete variable, and boundary layer methods for singular perturbation problems in partial derivatives. Consideration is also given to the computer simulation of supernova explosion, nonstationary internal waves in a stratified fluid, the description of turbulent flows by unsteady solutions of the Navier-Stokes equations, and the reduced Galerkin method for external diffraction problems using the spline approximation of fields.

Mathematical modelling and quantitative methods.

PubMed

Edler, L; Poirier, K; Dourson, M; Kleiner, J; Mileson, B; Nordmann, H; Renwick, A; Slob, W; Walton, K; Würtzen, G

2002-01-01

The present review reports on the mathematical methods and statistical techniques presently available for hazard characterisation. The state of the art of mathematical modelling and quantitative methods used currently for regulatory decision-making in Europe and additional potential methods for risk assessment of chemicals in food and diet are described. Existing practices of JECFA, FDA, EPA, etc., are examined for their similarities and differences. A framework is established for the development of new and improved quantitative methodologies. Areas for refinement, improvement and increase of efficiency of each method are identified in a gap analysis. Based on this critical evaluation, needs for future research are defined. It is concluded from our work that mathematical modelling of the dose-response relationship would improve the risk assessment process. An adequate characterisation of the dose-response relationship by mathematical modelling clearly requires the use of a sufficient number of dose groups to achieve a range of different response levels. This need not necessarily lead to an increase in the total number of animals in the study if an appropriate design is used. Chemical-specific data relating to the mode or mechanism of action and/or the toxicokinetics of the chemical should be used for dose-response characterisation whenever possible. It is concluded that a single method of hazard characterisation would not be suitable for all kinds of risk assessments, and that a range of different approaches is necessary so that the method used is the most appropriate for the data available and for the risk characterisation issue. Future refinements to dose-response characterisation should incorporate more clearly the extent of uncertainty and variability in the resulting output.

Modern Mathematical Topics in Chemistry.

ERIC Educational Resources Information Center

Henson, R. C.; Stumbles, A. M.

1979-01-01

Discusses how modern mathematical language can be used to develop chemical ideas in class. Examples for the application of Venn Diagrams and Flow Diagrams in teaching chemistry in the Nuffield courses are presented. (HM)

Mapping of Drug-like Chemical Universe with Reduced Complexity Molecular Frameworks.

PubMed

Kontijevskis, Aleksejs

2017-04-24

The emergence of the DNA-encoded chemical libraries (DEL) field in the past decade has attracted the attention of the pharmaceutical industry as a powerful mechanism for the discovery of novel drug-like hits for various biological targets. Nuevolution Chemetics technology enables DNA-encoded synthesis of billions of chemically diverse drug-like small molecule compounds, and the efficient screening and optimization of these, facilitating effective identification of drug candidates at an unprecedented speed and scale. Although many approaches have been developed by the cheminformatics community for the analysis and visualization of drug-like chemical space, most of them are restricted to the analysis of a maximum of a few millions of compounds and cannot handle collections of 10 8 -10 12 compounds typical for DELs. To address this big chemical data challenge, we developed the Reduced Complexity Molecular Frameworks (RCMF) methodology as an abstract and very general way of representing chemical structures. By further introducing RCMF descriptors, we constructed a global framework map of drug-like chemical space and demonstrated how chemical space occupied by multi-million-member drug-like Chemetics DNA-encoded libraries and virtual combinatorial libraries with >10 12 members could be analyzed and mapped without a need for library enumeration. We further validate the approach by performing RCMF-based searches in a drug-like chemical universe and mapping Chemetics library selection outputs for LSD1 targets on a global framework chemical space map.

The Interface between ChE and Mathematics: What Do Students Really Need?

ERIC Educational Resources Information Center

Graham, Michael D.; Ganter, Susan L.

2001-01-01

Summarizes the report given to the Committee on the Undergraduate Program in Mathematics of the Mathematical Association of America (MAA) who is developing new guidelines for instruction in mathematics with a chemical engineering group at Clemson University in order to list specific knowledge and skills in mathematics needed by engineering…

Chemical Equation Balancing.

ERIC Educational Resources Information Center

Blakley, G. R.

1982-01-01

Reviews mathematical techniques for solving systems of homogeneous linear equations and demonstrates that the algebraic method of balancing chemical equations is a matter of solving a system of homogeneous linear equations. FORTRAN programs using this matrix method to chemical equation balancing are available from the author. (JN)

Tuning the nonlinear optical absorption of reduced graphene oxide by chemical reduction.

PubMed

Shi, Hongfei; Wang, Can; Sun, Zhipei; Zhou, Yueliang; Jin, Kuijuan; Redfern, Simon A T; Yang, Guozhen

2014-08-11

Reduced graphene oxides with varying degrees of reduction have been produced by hydrazine reduction of graphene oxide. The linear and nonlinear optical properties of both graphene oxide as well as the reduced graphene oxides have been measured by single beam Z-scan measurement in the picosecond region. The results reveal both saturable absorption and two-photon absorption, strongly dependent on the intensity of the pump pulse: saturable absorption occurs at lower pump pulse intensity (~1.5 GW/cm2 saturation intensity) whereas two-photon absorption dominates at higher intensities (≥5.7 GW/cm2). Intriguingly, we find that the two-photon absorption coefficient (from 1.5 cm/GW to 4.5cm/GW) and the saturation intensity (from 1 GW/cm2 to 2 GW/cm2) vary with chemical reduction, which is ascribed to the varying concentrations of sp2 domains and sp2 clusters in the reduced graphene oxides. Our results not only provide an insight into the evolution of the nonlinear optical coefficient in reduced graphene oxide, but also suggest that chemical engineering techniques may usefully be applied to tune the nonlinear optical properties of various nano-materials, including atomically thick graphene sheets.

Mathematics anxiety reduces default mode network deactivation in response to numerical tasks.

PubMed

Pletzer, Belinda; Kronbichler, Martin; Nuerk, Hans-Christoph; Kerschbaum, Hubert H

2015-01-01

Mathematics anxiety is negatively related to mathematics performance, thereby threatening the professional success. Preoccupation with the emotional content of the stimuli may consume working memory resources, which may be reflected in decreased deactivation of areas associated with the default mode network (DMN) activated during self-referential and emotional processing. The common problem is that math anxiety is usually associated with poor math performance, so that any group differences are difficult to interpret. Here we compared the BOLD-response of 18 participants with high (HMAs) and 18 participants with low mathematics anxiety (LMAs) matched for their mathematical performance to two numerical tasks (number comparison, number bisection). During both tasks, we found stronger deactivation within the DMN in LMAs compared to HMAs, while BOLD-response in task-related activation areas did not differ between HMAs and LMAs. The difference in DMN deactivation between the HMA and LMA group was more pronounced in stimuli with additional requirement on inhibitory functions, but did not differ between number magnitude processing and arithmetic fact retrieval.

Mathematics anxiety reduces default mode network deactivation in response to numerical tasks

PubMed Central

Pletzer, Belinda; Kronbichler, Martin; Nuerk, Hans-Christoph; Kerschbaum, Hubert H.

2015-01-01

Mathematics anxiety is negatively related to mathematics performance, thereby threatening the professional success. Preoccupation with the emotional content of the stimuli may consume working memory resources, which may be reflected in decreased deactivation of areas associated with the default mode network (DMN) activated during self-referential and emotional processing. The common problem is that math anxiety is usually associated with poor math performance, so that any group differences are difficult to interpret. Here we compared the BOLD-response of 18 participants with high (HMAs) and 18 participants with low mathematics anxiety (LMAs) matched for their mathematical performance to two numerical tasks (number comparison, number bisection). During both tasks, we found stronger deactivation within the DMN in LMAs compared to HMAs, while BOLD-response in task-related activation areas did not differ between HMAs and LMAs. The difference in DMN deactivation between the HMA and LMA group was more pronounced in stimuli with additional requirement on inhibitory functions, but did not differ between number magnitude processing and arithmetic fact retrieval. PMID:25954179

Mass Transfer with Chemical Reaction.

ERIC Educational Resources Information Center

DeCoursey, W. J.

1987-01-01

Describes the organization of a graduate course dealing with mass transfer, particularly as it relates to chemical reactions. Discusses the course outline, including mathematics models of mass transfer, enhancement of mass transfer rates by homogeneous chemical reaction, and gas-liquid systems with chemical reaction. (TW)

The Chicken or the Egg? The Direction of the Relationship Between Mathematics Anxiety and Mathematics Performance.

PubMed

Carey, Emma; Hill, Francesca; Devine, Amy; Szücs, Dénes

2015-01-01

This review considers the two possible causal directions between mathematics anxiety (MA) and poor mathematics performance. Either poor maths performance may elicit MA (referred to as the Deficit Theory), or MA may reduce future maths performance (referred to as the Debilitating Anxiety Model). The evidence is in conflict: the Deficit Theory is supported by longitudinal studies and studies of children with mathematical learning disabilities, but the Debilitating Anxiety Model is supported by research which manipulates anxiety levels and observes a change in mathematics performance. It is suggested that this mixture of evidence might indicate a bidirectional relationship between MA and mathematics performance (the Reciprocal Theory), in which MA and mathematics performance can influence one another in a vicious cycle.

Reduced hazard chemicals for solid rocket motor production

NASA Technical Reports Server (NTRS)

Caddy, Larry A.; Bowman, Ross; Richards, Rex A.

1995-01-01

During the last three years. the NASA/Thiokol/industry team has developed and started implementation of an environmentally sound manufacturing plan for the continued production of solid rocket motors. NASA Marshall Space Flight Center (MSFC) and Thiokol Corporation have worked with other industry representatives and the U.S. Environmental Protection Agency (EPA) to prepare a comprehensive plan to eliminate all ozone depleting chemicals from manufacturing processes and reduce the use of other hazardous materials used to produce the space shuttle reusable solid rocket motors. The team used a classical approach for problem-solving combined with a creative synthesis of new approaches to attack this challenge.

76 FR 41371 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 3 Chemical...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

...The Bureau of Industry and Security (BIS) is seeking public comments on the impact of amending the Chemical Weapons Convention Regulations (CWCR) to reduce the concentration level at which the CWCR exempt certain mixtures containing Schedule 3 chemicals from the declaration requirements that apply to Schedule 3 chemical production and the reporting requirements that apply to exports and imports of Schedule 3 chemicals under the Chemical Weapons Convention (CWC). BIS is considering amending the CWCR declaration requirements that apply to the production of Schedule 3 chemicals to conform with the low concentration exemption adopted by the Organization for the Prohibition of Chemical Weapons (OPCW) in 2003, which applies when the concentration of any single Schedule 3 chemical in a mixture is ``30% or less,'' by weight or volume (whichever yields the lesser percent). Currently, the CWCR do not require the quantity of a Schedule 3 chemical contained in a mixture to be counted for declaration or reporting purposes if the concentration of the Schedule 3 chemical in the mixture is ``less than 80%'' by volume or weight (whichever yields the lesser percent). The current low concentration level was implemented in accordance with requirements set forth in the Chemical Weapons Convention Implementation Act (CWCIA). Accordingly, publication and implementation of regulatory changes affecting this low concentration exemption level would be contingent upon amendment of the CWCIA by the Congress. In addition, consistent with U.S. national discretion, BIS is considering amending the CWCR reporting requirements for exports and imports of Schedule 3 chemicals by reducing the low concentration exemption that applies to certain mixtures containing Schedule 3 chemicals from the current low concentration level of ``less than 80%'' of a Schedule 3 chemical by volume or weight (whichever yields the lesser percent) to a concentration of ``30% or less.''

Hierarchical Bayesian Approach To Reduce Uncertainty in the Aquatic Effect Assessment of Realistic Chemical Mixtures.

PubMed

Oldenkamp, Rik; Hendriks, Harrie W M; van de Meent, Dik; Ragas, Ad M J

2015-09-01

Species in the aquatic environment differ in their toxicological sensitivity to the various chemicals they encounter. In aquatic risk assessment, this interspecies variation is often quantified via species sensitivity distributions. Because the information available for the characterization of these distributions is typically limited, optimal use of information is essential to reduce uncertainty involved in the assessment. In the present study, we show that the credibility intervals on the estimated potentially affected fraction of species after exposure to a mixture of chemicals at environmentally relevant surface water concentrations can be extremely wide if a classical approach is followed, in which each chemical in the mixture is considered in isolation. As an alternative, we propose a hierarchical Bayesian approach, in which knowledge on the toxicity of chemicals other than those assessed is incorporated. A case study with a mixture of 13 pharmaceuticals demonstrates that this hierarchical approach results in more realistic estimations of the potentially affected fraction, as a result of reduced uncertainty in species sensitivity distributions for data-poor chemicals.

Programmable chemical controllers made from DNA.

PubMed

Chen, Yuan-Jyue; Dalchau, Neil; Srinivas, Niranjan; Phillips, Andrew; Cardelli, Luca; Soloveichik, David; Seelig, Georg

2013-10-01

Biological organisms use complex molecular networks to navigate their environment and regulate their internal state. The development of synthetic systems with similar capabilities could lead to applications such as smart therapeutics or fabrication methods based on self-organization. To achieve this, molecular control circuits need to be engineered to perform integrated sensing, computation and actuation. Here we report a DNA-based technology for implementing the computational core of such controllers. We use the formalism of chemical reaction networks as a 'programming language' and our DNA architecture can, in principle, implement any behaviour that can be mathematically expressed as such. Unlike logic circuits, our formulation naturally allows complex signal processing of intrinsically analogue biological and chemical inputs. Controller components can be derived from biologically synthesized (plasmid) DNA, which reduces errors associated with chemically synthesized DNA. We implement several building-block reaction types and then combine them into a network that realizes, at the molecular level, an algorithm used in distributed control systems for achieving consensus between multiple agents.

Programmable chemical controllers made from DNA

NASA Astrophysics Data System (ADS)

Chen, Yuan-Jyue; Dalchau, Neil; Srinivas, Niranjan; Phillips, Andrew; Cardelli, Luca; Soloveichik, David; Seelig, Georg

2013-10-01

Biological organisms use complex molecular networks to navigate their environment and regulate their internal state. The development of synthetic systems with similar capabilities could lead to applications such as smart therapeutics or fabrication methods based on self-organization. To achieve this, molecular control circuits need to be engineered to perform integrated sensing, computation and actuation. Here we report a DNA-based technology for implementing the computational core of such controllers. We use the formalism of chemical reaction networks as a 'programming language' and our DNA architecture can, in principle, implement any behaviour that can be mathematically expressed as such. Unlike logic circuits, our formulation naturally allows complex signal processing of intrinsically analogue biological and chemical inputs. Controller components can be derived from biologically synthesized (plasmid) DNA, which reduces errors associated with chemically synthesized DNA. We implement several building-block reaction types and then combine them into a network that realizes, at the molecular level, an algorithm used in distributed control systems for achieving consensus between multiple agents.

Evidence for shared genetic risk between ADHD symptoms and reduced mathematics ability: a twin study

PubMed Central

Greven, Corina U.; Kovas, Yulia; Willcutt, Erik G.; Petrill, Stephen A.; Plomin, Robert

2013-01-01

Background Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Methods Data came from more than 6,000 12-year-old twin pairs from the U.K. population-representative Twins Early Development Study. Parents rated each twin’s behaviour using a DSM-IV-based 18-item questionnaire of inattentive and hyperactive-impulsive ADHD symptoms. Mathematics tests based on the U.K. National Curriculum were completed by each twin. The twins also completed standardised tests of reading and general cognitive ability. Multivariate twin model fitting was applied. Results Inattentive and hyperactive-impulsive ADHD symptoms were highly heritable (67% and 73%, respectively). Mathematics ability was moderately heritable (46%). Mathematics ability and inattentiveness showed a significantly greater phenotypic correlation (rp=−0.26) and genetic correlation (rA=−0.41) than mathematics ability and hyperactivity-impulsivity (rp=−0.18; rA=−0.22). The genetic correlation between inattentiveness and mathematics ability was largely independent from hyperactivity-impulsivity, and was only partially accounted for by genetic influences related to reading and general cognitive ability. Conclusions Results revealed the novel finding that mathematics ability shows significantly stronger phenotypic and genetic associations with inattentiveness than with hyperactivity-impulsivity. Genetic associations between inattentiveness and mathematics ability could only partially be accounted for by hyperactivity-impulsivity, reading and general cognitive ability. Results suggest that mathematics ability is associated with ADHD symptoms largely because it shares genetic risk factors with inattentiveness, and provide further evidence for considering inattentiveness and hyperactivity-impulsivity separately. DNA markers for ADHD symptoms (especially inattentiveness) may also

Evidence for shared genetic risk between ADHD symptoms and reduced mathematics ability: a twin study.

PubMed

Greven, Corina U; Kovas, Yulia; Willcutt, Erik G; Petrill, Stephen A; Plomin, Robert

2014-01-01

Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Data came from more than 6,000 twelve-year-old twin pairs from the UK population-representative Twins Early Development Study. Parents rated each twin's behaviour using a DSM-IV-based 18-item questionnaire of inattentive and hyperactive-impulsive ADHD symptoms. Mathematics tests based on the UK National Curriculum were completed by each twin. The twins also completed standardised tests of reading and general cognitive ability. Multivariate twin model fitting was applied. Inattentive and hyperactive-impulsive ADHD symptoms were highly heritable (67% and 73% respectively). Mathematics ability was moderately heritable (46%). Mathematics ability and inattentiveness showed a significantly greater phenotypic correlation (r(p) = -.26) and genetic correlation (r(A) = -.41) than mathematics ability and hyperactivity-impulsivity (r(p) = -.18; r(A) = -.22). The genetic correlation between inattentiveness and mathematics ability was largely independent from hyperactivity-impulsivity, and was only partially accounted for by genetic influences related to reading and general cognitive ability. Results revealed the novel finding that mathematics ability shows significantly stronger phenotypic and genetic associations with inattentiveness than with hyperactivity-impulsivity. Genetic associations between inattentiveness and mathematics ability could only partially be accounted for by hyperactivity-impulsivity, reading and general cognitive ability. Results suggest that mathematics ability is associated with ADHD symptoms largely because it shares genetic risk factors with inattentiveness, and provide further evidence for considering inattentiveness and hyperactivity-impulsivity separately. DNA markers for ADHD symptoms (especially inattentiveness) may also be candidate risk factors for

The Chicken or the Egg? The Direction of the Relationship Between Mathematics Anxiety and Mathematics Performance

PubMed Central

Carey, Emma; Hill, Francesca; Devine, Amy; Szücs, Dénes

2016-01-01

This review considers the two possible causal directions between mathematics anxiety (MA) and poor mathematics performance. Either poor maths performance may elicit MA (referred to as the Deficit Theory), or MA may reduce future maths performance (referred to as the Debilitating Anxiety Model). The evidence is in conflict: the Deficit Theory is supported by longitudinal studies and studies of children with mathematical learning disabilities, but the Debilitating Anxiety Model is supported by research which manipulates anxiety levels and observes a change in mathematics performance. It is suggested that this mixture of evidence might indicate a bidirectional relationship between MA and mathematics performance (the Reciprocal Theory), in which MA and mathematics performance can influence one another in a vicious cycle. PMID:26779093

Equity and spatial reasoning: reducing the mathematical achievement gap in gender and social disadvantage

NASA Astrophysics Data System (ADS)

Lowrie, Tom; Jorgensen, Robyn

2018-03-01

Since the early 70s, there has been recognition that there are specific differences in achievement based on variables, such as gender and socio-economic background, in terms of mathematics performance. However, these differences are not unilateral but rather quite specific and relate strongly to spatial reasoning. This early work has paved the way for thinking critically about who achieves in mathematics and why. This project innovatively combines the strengths of the two Chief Investigators—Lowrie's work in spatial reasoning and Jorgensen's work in equity. The assumptions, the approach and theoretical framing used in the study unite quite disparate areas of mathematics education into a cogent research program that seeks to challenge some of the long-held views in the field of mathematics education.

Mathematical Notation in Bibliographic Databases.

ERIC Educational Resources Information Center

Pasterczyk, Catherine E.

1990-01-01

Discusses ways in which using mathematical symbols to search online bibliographic databases in scientific and technical areas can improve search results. The representations used for Greek letters, relations, binary operators, arrows, and miscellaneous special symbols in the MathSci, Inspec, Compendex, and Chemical Abstracts databases are…

Reduced and simplified chemical kinetics for air dissociation using Computational Singular Perturbation

NASA Technical Reports Server (NTRS)

Goussis, D. A.; Lam, S. H.; Gnoffo, P. A.

1990-01-01

The Computational Singular Perturbation CSP methods is employed (1) in the modeling of a homogeneous isothermal reacting system and (2) in the numerical simulation of the chemical reactions in a hypersonic flowfield. Reduced and simplified mechanisms are constructed. The solutions obtained on the basis of these approximate mechanisms are shown to be in very good agreement with the exact solution based on the full mechanism. Physically meaningful approximations are derived. It is demonstrated that the deduction of these approximations from CSP is independent of the complexity of the problem and requires no intuition or experience in chemical kinetics.

Scramjet Combustor Simulations Using Reduced Chemical Kinetics for Practical Fuels

DTIC Science & Technology

2003-12-01

the aerospace industry in reducing prototype and testing costs and the time needed to bring products to market . Accurate simulation of chemical...JP-8 kinetics and soot models into the UNICORN CFD code (Montgomery et al., 2003a) NSF Phase I and II SBIRs for development of a computer-assisted...divided by diameter QSS quasi-steady state REI Reaction Engineering International UNICORN UNsteady Ignition and COmbustion with ReactioNs VULCAN Viscous Upwind aLgorithm for Complex flow ANalysis

Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors

NASA Astrophysics Data System (ADS)

Kehayias, Christopher E.; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

2013-06-01

Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors.

PubMed

Kehayias, Christopher E; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

2013-06-21

Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

Using Mathematics, Mathematical Applications, Mathematical Modelling, and Mathematical Literacy: A Theoretical Study

ERIC Educational Resources Information Center

Mumcu, Hayal Yavuz

2016-01-01

The purpose of this theoretical study is to explore the relationships between the concepts of using mathematics in the daily life, mathematical applications, mathematical modelling, and mathematical literacy. As these concepts are generally taken as independent concepts in the related literature, they are confused with each other and it becomes…

Activation of aluminum as an effective reducing agent by pitting corrosion for wet-chemical synthesis.

PubMed

Li, Wei; Cochell, Thomas; Manthiram, Arumugam

2013-01-01

Metallic aluminum (Al) is of interest as a reducing agent because of its low standard reduction potential. However, its surface is invariably covered with a dense aluminum oxide film, which prevents its effective use as a reducing agent in wet-chemical synthesis. Pitting corrosion, known as an undesired reaction destroying Al and is enhanced by anions such as F⁻, Cl⁻, and Br⁻ in aqueous solutions, is applied here for the first time to activate Al as a reducing agent for wet-chemical synthesis of a diverse array of metals and alloys. Specifically, we demonstrate the synthesis of highly dispersed palladium nanoparticles on carbon black with stabilizers and the intermetallic Cu₂Sb/C, which are promising candidates, respectively, for fuel cell catalysts and lithium-ion battery anodes. Atomic hydrogen, an intermediate during the pitting corrosion of Al in protonic solvents (e.g., water and ethylene glycol), is validated as the actual reducing agent.

Physical and mathematical modeling of antimicrobial photodynamic therapy

NASA Astrophysics Data System (ADS)

Bürgermeister, Lisa; López, Fernando Romero; Schulz, Wolfgang

2014-07-01

Antimicrobial photodynamic therapy (aPDT) is a promising method to treat local bacterial infections. The therapy is painless and does not cause bacterial resistances. However, there are gaps in understanding the dynamics of the processes, especially in periodontal treatment. This work describes the advances in fundamental physical and mathematical modeling of aPDT used for interpretation of experimental evidence. The result is a two-dimensional model of aPDT in a dental pocket phantom model. In this model, the propagation of laser light and the kinetics of the chemical reactions are described as coupled processes. The laser light induces the chemical processes depending on its intensity. As a consequence of the chemical processes, the local optical properties and distribution of laser light change as well as the reaction rates. The mathematical description of these coupled processes will help to develop treatment protocols and is the first step toward an inline feedback system for aPDT users.

Mathematical Ability Relies on Knowledge, Too

ERIC Educational Resources Information Center

Sweller, John; Clark, Richard E.; Kirschner, Paul A.

2011-01-01

Recent "reform" curricula both ignore the absence of supporting data and completely misunderstand the role of problem solving in cognition. If, the argument goes, teachers are not really teaching people mathematics but rather are teaching them some form of general problem solving, then mathematical content can be reduced in importance. According…

Chemically stabilized reduced graphene oxide/zirconia nanocomposite: synthesis and characterization

NASA Astrophysics Data System (ADS)

Sagadevan, Suresh; Zaman Chowdhury, Zaira; Enamul Hoque, Md; Podder, Jiban

2017-11-01

In this research, chemical method was used to fabricate reduced graphene oxide/zirconia (rGO/ZrO2) nanocomposite. X-ray Diffraction analysis (XRD) was carried out to examine the crystalline structure of the nanocomposites. The nanocomposite prepared here has average crystallite size of 14 nm. The surface morphology was observed using scanning electron microscopic analysis (SEM) coupled with electron dispersion spectroscopy (EDS) to detect the chemical element over the surface of the nanocomposites. High-resolution Transmission electron microscopic analysis (HR-TEM) was carried out to determine the particle size and shape of the nanocomposites. The optical property of the prepared samples was determined using UV-visible absorption spectrum. The functional groups were identified using FTIR and Raman spectroscopic analysis. Efficient, cost effective and properly optimized synthesis process of rGO/ZrO2 nanocomposite can ensure the presence of infiltrating graphene network inside the ZrO2 matrix to enhance the electrical properties of the hybrid composites up to a greater scale. Thus the dielectric constant, dielectric loss and AC conductivity of the prepared sample was measured at various frequencies and temperatures. The analytical results obtained here confirmed the homogeneous dispersion of ZrO2 nanostructures over the surface of reduced graphene oxide nanosheets. Overall, the research demonstrated that the rGO/ZrO2 nano-hybrid structure fabricated here can be considered as a promising candidate for applications in nanoelectronics and optoelectronics.

Programmable chemical controllers made from DNA

PubMed Central

Chen, Yuan-Jyue; Dalchau, Neil; Srinivas, Niranjan; Phillips, Andrew; Cardelli, Luca; Soloveichik, David; Seelig, Georg

2014-01-01

Biological organisms use complex molecular networks to navigate their environment and regulate their internal state. The development of synthetic systems with similar capabilities could lead to applications such as smart therapeutics or fabrication methods based on self-organization. To achieve this, molecular control circuits need to be engineered to perform integrated sensing, computation and actuation. Here we report a DNA-based technology for implementing the computational core of such controllers. We use the formalism of chemical reaction networks as a 'programming language', and our DNA architecture can, in principle, implement any behaviour that can be mathematically expressed as such. Unlike logic circuits, our formulation naturally allows complex signal processing of intrinsically analogue biological and chemical inputs. Controller components can be derived from biologically synthesized (plasmid) DNA, which reduces errors associated with chemically synthesized DNA. We implement several building-block reaction types and then combine them into a network that realizes, at the molecular level, an algorithm used in distributed control systems for achieving consensus between multiple agents. PMID:24077029

Modelling Mathematical Reasoning in Physics Education

NASA Astrophysics Data System (ADS)

Uhden, Olaf; Karam, Ricardo; Pietrocola, Maurício; Pospiech, Gesche

2012-04-01

Many findings from research as well as reports from teachers describe students' problem solving strategies as manipulation of formulas by rote. The resulting dissatisfaction with quantitative physical textbook problems seems to influence the attitude towards the role of mathematics in physics education in general. Mathematics is often seen as a tool for calculation which hinders a conceptual understanding of physical principles. However, the role of mathematics cannot be reduced to this technical aspect. Hence, instead of putting mathematics away we delve into the nature of physical science to reveal the strong conceptual relationship between mathematics and physics. Moreover, we suggest that, for both prospective teaching and further research, a focus on deeply exploring such interdependency can significantly improve the understanding of physics. To provide a suitable basis, we develop a new model which can be used for analysing different levels of mathematical reasoning within physics. It is also a guideline for shifting the attention from technical to structural mathematical skills while teaching physics. We demonstrate its applicability for analysing physical-mathematical reasoning processes with an example.

Reducing health risk assigned to organic emissions from a chemical weapons incinerator.

PubMed

Laman, David M; Weiler, B Douglas; Skeen, Rodney S

2013-03-01

Organic emissions from a chemical weapons incinerator have been characterized with an improved set of analytical methods to reduce the human health risk assigned to operations of the facility. A gas chromatography/mass selective detection method with substantially reduced detection limits has been used in conjunction with scanning electron microscopy/energy dispersive X-ray spectrometry and Fourier transform infrared microscopy to improve the speciation of semi-volatile and non-volatile organics emitted from the incinerator. The reduced detection limits have allowed a significant reduction in the assumed polycyclic aromatic hydrocarbon (PAH) and aminobiphenyl (ABP) emission rates used as inputs to the human health risk assessment for the incinerator. A mean factor of 17 decrease in assigned human health risk is realized for six common local exposure scenarios as a result of the reduced PAH and ABP detection limits.

[Mathematical exploration of essence of herbal properties based on "Three-Elements" theory].

PubMed

Jin, Rui; Zhao, Qian; Zhang, Bing

2014-10-01

Herbal property theory of traditional Chinese medicines is the theoretical guidance on authentication of medicinal plants, herborization, preparation of herbal medicines for decoction and clinical application, with important theoretical value and prac- tical significance. Our research team proposed the "three-element" theory for herbal properties for the first time, conducted a study by using combined methods of philology, chemistry, pharmacology and mathematics, and then drew the research conclusion that herbal properties are defined as the chemical compositions-based comprehensive expression with complex and multi-level (positive/negative) biological effects in specific organism state. In this paper, researchers made a systematic mathematical analysis in four aspects--the correlation between herbal properties and chemical component factors, the correlation between herbal properties and organism state fac- tor, the correlation between herbal properties and biological effect factor and the integration study of the three elements, proposed future outlook, and provided reference to mathematical studies and mathematical analysis of herbal properties.

In situ chemical synthesis of ruthenium oxide/reduced graphene oxide nanocomposites for electrochemical capacitor applications.

PubMed

Kim, Ji-Young; Kim, Kwang-Heon; Yoon, Seung-Beom; Kim, Hyun-Kyung; Park, Sang-Hoon; Kim, Kwang-Bum

2013-08-07

An in situ chemical synthesis approach has been developed to prepare ruthenium oxide/reduced graphene oxide (RGO) nanocomposites. It is found that as the C/O ratio increases, the number density of RuO2 nanoparticles decreases, because the chemical interaction between the Ru ions and the oxygen-containing functional groups provides anchoring sites where the nucleation of particles takes place. For electrochemical capacitor applications, the microwave-hydrothermal process was carried out to improve the conductivity of RGO in RuO2/RGO nanocomposites. The significant improvement in capacitance and high rate capability might result from the RuO2 nanoparticles used as spacers that make the interior layers of the reduced graphene oxide electrode available for electrolyte access.

Mathematical Modeling of Diverse Phenomena

NASA Technical Reports Server (NTRS)

Howard, J. C.

1979-01-01

Tensor calculus is applied to the formulation of mathematical models of diverse phenomena. Aeronautics, fluid dynamics, and cosmology are among the areas of application. The feasibility of combining tensor methods and computer capability to formulate problems is demonstrated. The techniques described are an attempt to simplify the formulation of mathematical models by reducing the modeling process to a series of routine operations, which can be performed either manually or by computer.

Balancing Chemical Reactions With Matrix Methods and Computer Assistance. Applications of Linear Algebra to Chemistry. Modules and Monographs in Undergraduate Mathematics and Its Applications Project. UMAP Unit 339.

ERIC Educational Resources Information Center

Grimaldi, Ralph P.

This material was developed to provide an application of matrix mathematics in chemistry, and to show the concepts of linear independence and dependence in vector spaces of dimensions greater than three in a concrete setting. The techniques presented are not intended to be considered as replacements for such chemical methods as oxidation-reduction…

Mathematics anxiety and mathematics achievement

NASA Astrophysics Data System (ADS)

Sherman, Brian F.; Wither (Post.), David P.

2003-09-01

This paper is a distillation of the major result from the 1998 Ph.D. thesis of the late David Wither. It details a longitudinal study over five years of the relationship between mathematics anxiety and mathematics achievement. It starts from the already well documented negative correlation between the two, and seeks to establish one of the three hypotheses—that mathematics anxiety causes an impairment of mathematics achievement; that lack of mathematics achievement causes mathematics anxiety; or that there is a third underlying cause of the two.

Reducing aquatic hazards of industrial chemicals: probabilistic assessment of sustainable molecular design guidelines.

PubMed

Connors, Kristin A; Voutchkova-Kostal, Adelina M; Kostal, Jakub; Anastas, Paul; Zimmerman, Julie B; Brooks, Bryan W

2014-08-01

Basic toxicological information is lacking for the majority of industrial chemicals. In addition to increasing empirical toxicity data through additional testing, prospective computational approaches to drug development aim to serve as a rational basis for the design of chemicals with reduced toxicity. Recent work has resulted in the derivation of a "rule of 2," wherein chemicals with an octanol-water partition coefficient (log P) less than 2 and a difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital (ΔE) greater than 9 (log P<2 and ΔE >9 eV) are predicted to be 4 to 5 times less likely to elicit acute or chronic toxicity to model aquatic organisms. The present study examines potential reduction of aquatic toxicity hazards from industrial chemicals if these 2 molecular design guidelines were employed. Probabilistic hazard assessment approaches were used to model the likelihood of encountering industrial chemicals exceeding toxicological categories of concern both with and without the rule of 2. Modeling predicted that utilization of these molecular design guidelines for log P and ΔE would appreciably decrease the number of chemicals that would be designated to be of "high" and "very high" concern for acute and chronic toxicity to standard model aquatic organisms and end points as defined by the US Environmental Protection Agency. For example, 14.5% of chemicals were categorized as having high and very high acute toxicity to the fathead minnow model, whereas only 3.3% of chemicals conforming to the design guidelines were predicted to be in these categories. Considerations of specific chemical classes (e.g., aldehydes), chemical attributes (e.g., ionization), and adverse outcome pathways in representative species (e.g., receptor-mediated responses) could be used to derive future property guidelines for broader classes of contaminants. © 2014 SETAC.

Biodegradation of organic chemicals in soil/water microcosms system: Model development

USGS Publications Warehouse

Liu, L.; Tindall, J.A.; Friedel, M.J.; Zhang, W.

2007-01-01

The chemical interactions of hydrophobic organic contaminants with soils and sediments may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints. In order to illustrate the recalcitrance of chemical to degradation on sites, a sorption mechanism of intraparticle sequestration was postulated to operate on chemical remediation sites. Pseudo-first order sequestration kinetics is used in the study with the hypothesis that sequestration is an irreversibly surface-mediated process. A mathematical model based on mass balance equations was developed to describe the fate of chemical degradation in soil/water microcosm systems. In the model, diffusion was represented by Fick's second law, local sorption-desorption by a linear isotherm, irreversible sequestration by a pseudo-first order kinetics and biodegradation by Monod kinetics. Solutions were obtained to provide estimates of chemical concentrations. The mathematical model was applied to a benzene biodegradation batch test and simulated model responses correlated well compared to measurements of biodegradation of benzene in the batch soil/water microcosm system. A sensitivity analysis was performed to assess the effects of several parameters on model behavior. Overall chemical removal rate decreased and sequestration increased quickly with an increase in the sorption partition coefficient. When soil particle radius, a, was greater than 1 mm, an increase in radius produced a significant decrease in overall chemical removal rate as well as an increase in sequestration. However, when soil particle radius was less than 0.1 mm, an increase in radius resulted in small changes in the removal rate and sequestration. As pseudo-first order sequestration rate increased, both chemical removal rate and sequestration increased slightly. Model simulation results showed that desorption resistance played an important role in the bioavailability of organic chemicals in porous

The subtle business of model reduction for stochastic chemical kinetics.

PubMed

Gillespie, Dan T; Cao, Yang; Sanft, Kevin R; Petzold, Linda R

2009-02-14

This paper addresses the problem of simplifying chemical reaction networks by adroitly reducing the number of reaction channels and chemical species. The analysis adopts a discrete-stochastic point of view and focuses on the model reaction set S(1)<=>S(2)-->S(3), whose simplicity allows all the mathematics to be done exactly. The advantages and disadvantages of replacing this reaction set with a single S(3)-producing reaction are analyzed quantitatively using novel criteria for measuring simulation accuracy and simulation efficiency. It is shown that in all cases in which such a model reduction can be accomplished accurately and with a significant gain in simulation efficiency, a procedure called the slow-scale stochastic simulation algorithm provides a robust and theoretically transparent way of implementing the reduction.

Collective Surfing of Chemically Active Particles

NASA Astrophysics Data System (ADS)

Masoud, Hassan; Shelley, Michael J.

2014-03-01

We study theoretically the collective dynamics of immotile particles bound to a 2D surface atop a 3D fluid layer. These particles are chemically active and produce a chemical concentration field that creates surface-tension gradients along the surface. The resultant Marangoni stresses create flows that carry the particles, possibly concentrating them. For a 3D diffusion-dominated concentration field and Stokesian fluid we show that the surface dynamics of active particle density can be determined using nonlocal 2D surface operators. Remarkably, we also show that for both deep or shallow fluid layers this surface dynamics reduces to the 2D Keller-Segel model for the collective chemotactic aggregation of slime mold colonies. Mathematical analysis has established that the Keller-Segel model can yield finite-time, finite-mass concentration singularities. We show that such singular behavior occurs in our finite-depth system, and study the associated 3D flow structures.

Nonlinear model predictive control for chemical looping process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Abhinaya; Lei, Hao; Lou, Xinsheng

A control system for optimizing a chemical looping ("CL") plant includes a reduced order mathematical model ("ROM") that is designed by eliminating mathematical terms that have minimal effect on the outcome. A non-linear optimizer provides various inputs to the ROM and monitors the outputs to determine the optimum inputs that are then provided to the CL plant. An estimator estimates the values of various internal state variables of the CL plant. The system has one structure adapted to control a CL plant that only provides pressure measurements in the CL loops A and B, a second structure adapted to amore » CL plant that provides pressure measurements and solid levels in both loops A, and B, and a third structure adapted to control a CL plant that provides full information on internal state variables. A final structure provides a neural network NMPC controller to control operation of loops A and B.« less

Chemical databases evaluated by order theoretical tools.

PubMed

Voigt, Kristina; Brüggemann, Rainer; Pudenz, Stefan

2004-10-01

Data on environmental chemicals are urgently needed to comply with the future chemicals policy in the European Union. The availability of data on parameters and chemicals can be evaluated by chemometrical and environmetrical methods. Different mathematical and statistical methods are taken into account in this paper. The emphasis is set on a new, discrete mathematical method called METEOR (method of evaluation by order theory). Application of the Hasse diagram technique (HDT) of the complete data-matrix comprising 12 objects (databases) x 27 attributes (parameters + chemicals) reveals that ECOTOX (ECO), environmental fate database (EFD) and extoxnet (EXT)--also called multi-database databases--are best. Most single databases which are specialised are found in a minimal position in the Hasse diagram; these are biocatalysis/biodegradation database (BID), pesticide database (PES) and UmweltInfo (UMW). The aggregation of environmental parameters and chemicals (equal weight) leads to a slimmer data-matrix on the attribute side. However, no significant differences are found in the "best" and "worst" objects. The whole approach indicates a rather bad situation in terms of the availability of data on existing chemicals and hence an alarming signal concerning the new and existing chemicals policies of the EEC.

Chemical treatment costs reduced with in-pond receway systems comopared to traditional pond aquaculture

USDA-ARS?s Scientific Manuscript database

Production systems such as in-pond raceway systems (IPRS) and split ponds are providing an alternative to traditional pond culture for raising catfish in several southeastern states. One advantage noted by farmers utilizing these systems is the reduced cost associated with the chemical treatment of...

Multiscale Mathematics for Biomass Conversion to Renewable Hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plechac, Petr

2016-03-01

The overall objective of this project was to develop multiscale models for understanding and eventually designing complex processes for renewables. To the best of our knowledge, our work is the first attempt at modeling complex reacting systems, whose performance relies on underlying multiscale mathematics and developing rigorous mathematical techniques and computational algorithms to study such models. Our specific application lies at the heart of biofuels initiatives of DOE and entails modeling of catalytic systems, to enable economic, environmentally benign, and efficient conversion of biomass into either hydrogen or valuable chemicals.

Predicting Relationships between Mathematics Anxiety, Mathematics Teaching Anxiety, Self-Efficacy Beliefs towards Mathematics and Mathematics Teaching

ERIC Educational Resources Information Center

Unlu, Melihan; Ertekin, Erhan; Dilmac, Bulent

2017-01-01

The purpose of the research is to investigate the relationships between self-efficacy beliefs toward mathematics, mathematics anxiety and self-efficacy beliefs toward mathematics teaching, mathematics teaching anxiety variables and testing the relationships between these variables with structural equation model. The sample of the research, which…

A Study of Coordination Between Mathematics and Chemistry in the Pre-Technical Program.

ERIC Educational Resources Information Center

Loiseau, Roger A.

This research was undertaken to determine whether the mathematics course offered to students taking courses in chemical technology was adequate. Students in a regular class and an experimental class were given mathematics and chemistry pretests and posttests. The experimental class was taught using a syllabus designed to maximize the coherence…

Examining the Relationship between Secondary Mathematics Teachers' Self-Efficacy, Attitudes, and Use of Technology to Support Communication and Mathematics Literacy

ERIC Educational Resources Information Center

Letwinsky, Karim Medico

2017-01-01

The rich language surrounding mathematical concepts often is reduced in many classrooms to a narrow process of memorizing isolated procedures with little context. This approach has proven to be detrimental to students' ability to understand mathematics at deeper levels and remain engaged with this content. The current generation of students values…

The subtle business of model reduction for stochastic chemical kinetics

NASA Astrophysics Data System (ADS)

Gillespie, Dan T.; Cao, Yang; Sanft, Kevin R.; Petzold, Linda R.

2009-02-01

This paper addresses the problem of simplifying chemical reaction networks by adroitly reducing the number of reaction channels and chemical species. The analysis adopts a discrete-stochastic point of view and focuses on the model reaction set S1⇌S2→S3, whose simplicity allows all the mathematics to be done exactly. The advantages and disadvantages of replacing this reaction set with a single S3-producing reaction are analyzed quantitatively using novel criteria for measuring simulation accuracy and simulation efficiency. It is shown that in all cases in which such a model reduction can be accomplished accurately and with a significant gain in simulation efficiency, a procedure called the slow-scale stochastic simulation algorithm provides a robust and theoretically transparent way of implementing the reduction.

The Effect of Mathematics Research on Mathematics Majors' Mathematical Beliefs

ERIC Educational Resources Information Center

Goodson, Joshua E.

2012-01-01

This is a dissertation about the beliefs that mathematics majors have about mathematics and how their beliefs are affected by the introduction of mathematics research. The mathematics research presented to the students dealt with counting regular orbits of an action. Research has shown that the beliefs that teachers hold about mathematics…

Teachers' Mathematics as Mathematics-at-Work

ERIC Educational Resources Information Center

Bednarz, Nadine; Proulx, Jérôme

2017-01-01

Through recognising mathematics teachers as professionals who use mathematics in their workplace, this article traces a parallel between the mathematics enacted by teachers in their practice and the mathematics used in workplaces found in studies of professionals (e.g. nurses, engineers, bankers). This parallel is developed through the five…

The Effectiveness of the North Carolina Early Mathematics Placement Test in Preparing High School Students for College-Level Introductory Mathematics Courses

ERIC Educational Resources Information Center

Hilgoe, Ellen; Brinkley, Jason; Hattingh, Johannes; Bernhardt, Robert

2016-01-01

Since its establishment in 1996, the North Carolina Early Mathematics Placement Testing (NC EMPT) Program has provided a low stakes reality check of readiness for college-level mathematics to more than 600,000 high school students statewide. The program strives to help reduce the percentage of incoming college freshmen requiring mathematics…

Rational application of chemicals in response to oil spills may reduce environmental damage.

PubMed

Tamis, Jacqueline E; Jongbloed, Ruud H; Karman, Chris C; Koops, Wierd; Murk, Albertinka J

2012-04-01

Oil spills, for example those due to tanker collisions and groundings or platform accidents, can have huge adverse impacts on marine systems. The impact of an oil spill at sea depends on a number of factors, such as spill volume, type of oil spilled, weather conditions, and proximity to environmentally, economically, or socially sensitive areas. Oil spilled at sea threatens marine organisms, whole ecosystems, and economic resources in the immediate vicinity, such as fisheries, aquaculture, recreation, and tourism. Adequate response to any oil spill to minimize damage is therefore of great importance. The common response to an oil spill is to remove all visible oil from the water surface, either mechanically or by using chemicals to disperse the oil into the water column to biodegrade. This is not always the most suitable response to an oil spill, as the chemical application itself may also have adverse effects, or no response may be needed. In this article we discuss advantages and disadvantages of using chemical treatments to reduce the impact of an oil spill in relation to the conditions of the spill. The main characteristics of chemical treatment agents are discussed and presented within the context of a basic decision support scheme. Copyright © 2011 SETAC.

Examining Fourth-Grade Mathematics Writing: Features of Organization, Mathematics Vocabulary, and Mathematical Representations

ERIC Educational Resources Information Center

Hebert, Michael A.; Powell, Sarah R.

2016-01-01

Increasingly, students are expected to write about mathematics. Mathematics writing may be informal (e.g., journals, exit slips) or formal (e.g., writing prompts on high-stakes mathematics assessments). In order to develop an effective mathematics-writing intervention, research needs to be conducted on how students organize mathematics writing and…

Teaching Mathematical Modeling in Mathematics Education

ERIC Educational Resources Information Center

Saxena, Ritu; Shrivastava, Keerty; Bhardwaj, Ramakant

2016-01-01

Mathematics is not only a subject but it is also a language consisting of many different symbols and relations. Taught as a compulsory subject up the 10th class, students are then able to choose whether or not to study mathematics as a main subject. The present paper discusses mathematical modeling in mathematics education. The article provides…

Mathematical Modeling and Pure Mathematics

ERIC Educational Resources Information Center

Usiskin, Zalman

2015-01-01

Common situations, like planning air travel, can become grist for mathematical modeling and can promote the mathematical ideas of variables, formulas, algebraic expressions, functions, and statistics. The purpose of this article is to illustrate how the mathematical modeling that is present in everyday situations can be naturally embedded in…

Androgen receptor mediated compensation of estradiol in response to aromatase inhibition: a mathematical model

EPA Science Inventory

Chemicals in the environment have the potential to cause reproductive toxicity by acting on the hypothalamus-pituitary-gonadal (HPG) axis. We have developed a mathematical model to predict chemical impacts on reproductive hormone production in the highly conserved HPG axis using...

Linking Preservice Teachers' Mathematics Self-Efficacy and Mathematics Teaching Efficacy to Their Mathematical Performance

ERIC Educational Resources Information Center

Bates, Alan B.; Latham, Nancy; Kim, Jin-ah

2011-01-01

This study examined preservice teachers' mathematics self-efficacy and mathematics teaching efficacy and compared them to their mathematical performance. Participants included 89 early childhood preservice teachers at a Midwestern university. Instruments included the Mathematics Self-Efficacy Scale (MSES), Mathematics Teaching Efficacy Beliefs…

A mathematical model for jet engine combustor pollutant emissions

NASA Technical Reports Server (NTRS)

Boccio, J. L.; Weilerstein, G.; Edelman, R. B.

1973-01-01

Mathematical modeling for the description of the origin and disposition of combustion-generated pollutants in gas turbines is presented. A unified model in modular form is proposed which includes kinetics, recirculation, turbulent mixing, multiphase flow effects, swirl and secondary air injection. Subelements of the overall model were applied to data relevant to laboratory reactors and practical combustor configurations. Comparisons between the theory and available data show excellent agreement for basic CO/H2/Air chemical systems. For hydrocarbons the trends are predicted well including higher-than-equilibrium NO levels within the fuel rich regime. Although the need for improved accuracy in fuel rich combustion is indicated, comparisons with actual jet engine data in terms of the effect of combustor-inlet temperature is excellent. In addition, excellent agreement with data is obtained regarding reduced NO emissions with water droplet and steam injection.

Contrasts in Mathematical Challenges in A-Level Mathematics and Further Mathematics, and Undergraduate Mathematics Examinations

ERIC Educational Resources Information Center

Darlington, Ellie

2014-01-01

This article describes part of a study which investigated the role of questions in students' approaches to learning mathematics at the secondary-tertiary interface, focussing on the enculturation of students at the University of Oxford. Use of the Mathematical Assessment Task Hierarchy taxonomy revealed A-level Mathematics and Further Mathematics…

Mathematical modeling in realistic mathematics education

NASA Astrophysics Data System (ADS)

Riyanto, B.; Zulkardi; Putri, R. I. I.; Darmawijoyo

2017-12-01

The purpose of this paper is to produce Mathematical modelling in Realistics Mathematics Education of Junior High School. This study used development research consisting of 3 stages, namely analysis, design and evaluation. The success criteria of this study were obtained in the form of local instruction theory for school mathematical modelling learning which was valid and practical for students. The data were analyzed using descriptive analysis method as follows: (1) walk through, analysis based on the expert comments in the expert review to get Hypothetical Learning Trajectory for valid mathematical modelling learning; (2) analyzing the results of the review in one to one and small group to gain practicality. Based on the expert validation and students’ opinion and answers, the obtained mathematical modeling problem in Realistics Mathematics Education was valid and practical.

MATHEMATICAL MODELING OF PESTICIDES IN THE ENVIRONMENT: CURRENT AND FUTURE DEVELOPMENTS

EPA Science Inventory

Transport models, total ecosystem models with aggregated linear approximations, evaluative models, hierarchical models, and influence analysis methods are mathematical techniques that are particularly applicable to the problems encountered when characterizing pesticide chemicals ...

Musical Chemistry: Integrating Chemistry and Music--A Nine-Part Tutorial for Generating Music from Chemical Processes

ERIC Educational Resources Information Center

Kumbar, Mahadev

2007-01-01

This paper synopsizes a series of nine tutorials investigating how various chemical processes can be shown to have musical aspects. Both chemistry and music share a common language: mathematics. Interesting music can be created as chemical reactions--mediated by instrumentation and mathematics (e.g., spectrometry and discrete Fourier…

High School Mathematics Curricula, University Mathematics Placement Recommendations, and Student University Mathematics Performance

ERIC Educational Resources Information Center

Norman, Ke Wu; Medhanie, Amanuel G.; Harwell, Michael R.; Anderson, Edwin; Post, Thomas R.

2011-01-01

Recent "math wars" have drawn attention to how well various high school mathematics curricula prepare students for college-level mathematics. The purpose of this study was to investigate the relationship between the high school mathematics curricula and students' post-secondary mathematics placement recommendation, specifically how…

Using Mathematics Literature with Prospective Secondary Mathematics Teachers

ERIC Educational Resources Information Center

Jett, Christopher C.

2014-01-01

Literature in mathematics has been found to foster positive improvements in mathematics learning. This manuscript reports on a mathematics teacher educator's use of literature via literature circles with 11 prospective secondary mathematics teachers in a mathematics content course. Using survey and reflection data, the author found that…

Mathematical Language Skills of Mathematics Prospective Teachers

ERIC Educational Resources Information Center

Gürefe, Nejla

2018-01-01

Effective mathematics teaching can be actualized only with correct use of the mathematical content language which comprises mathematical rules, concepts, symbols and terms. In this research, it was aimed to examine the mathematics prospective teachers' content language skills in some basic geometric concepts which are ray, angle, polygon,…

Mathematical tool from corn stover TGA to determine its composition.

PubMed

Freda, Cesare; Zimbardi, Francesco; Nanna, Francesco; Viola, Egidio

2012-08-01

Corn stover was treated by steam explosion process at four different temperatures. A fraction of the four exploded matters was extracted by water. The eight samples (four from steam explosion and four from water extraction of exploded matters) were analysed by wet chemical way to quantify the amount of cellulose, hemicellulose and lignin. Thermogravimetric analysis in air atmosphere was executed on the eight samples. A mathematical tool was developed, using TGA data, to determine the composition of corn stover in terms of cellulose, hemicellulose and lignin. It uses the biomass degradation temperature as multiple linear function of the cellulose, hemicellulose and lignin content of the biomass with interactive terms. The mathematical tool predicted cellulose, hemicellulose and lignin contents with average absolute errors of 1.69, 5.59 and 0.74 %, respectively, compared to the wet chemical method.

Doing Mathematics with Purpose: Mathematical Text Types

ERIC Educational Resources Information Center

Dostal, Hannah M.; Robinson, Richard

2018-01-01

Mathematical literacy includes learning to read and write different types of mathematical texts as part of purposeful mathematical meaning making. Thus in this article, we describe how learning to read and write mathematical texts (proof text, algorithmic text, algebraic/symbolic text, and visual text) supports the development of students'…

Annual Perspectives in Mathematics Education 2016: Mathematical Modeling and Modeling Mathematics

ERIC Educational Resources Information Center

Hirsch, Christian R., Ed.; McDuffie, Amy Roth, Ed.

2016-01-01

Mathematical modeling plays an increasingly important role both in real-life applications--in engineering, business, the social sciences, climate study, advanced design, and more--and within mathematics education itself. This 2016 volume of "Annual Perspectives in Mathematics Education" ("APME") focuses on this key topic from a…

Dissolution of synthetic uranium dibutyl phosphate deposits in oxidizing and reducing chemical formulations.

PubMed

Rufus, A L; Sathyaseelan, V S; Narasimhan, S V; Velmurugan, S

2013-06-15

Permanganate and nitrilotriacetic acid (NTA) based dilute chemical formulations were evaluated for the dissolution of uranium dibutyl phosphate (U-DBP), a compound that deposits over the surfaces of nuclear reprocessing plants and waste storage tanks. A combination of an acidic, oxidizing treatment (nitric acid with permanganate) followed by reducing treatment (NTA based formulation) efficiently dissolved the U-DBP deposits. The dissolution isotherm of U-DBP in its as precipitated form followed a logarithmic fit. The same chemical treatment was also effective in dissolving U-DBP coated on the surface of 304-stainless steel, while resulting in minimal corrosion of the stainless steel substrate material. Investigation of uranium recovery from the resulting decontamination solutions by ion exchange with a bed of mixed anion and cation resins showed quantitative removal of uranium. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemically reduced graphene oxide-P25-Au nanocomposite materials and their photoelectrocatalytic and photocatalytic applications.

PubMed

Praveen, Raju; Ramaraj, Ramasamy

2016-10-05

Visible light active photocatalysts consisting of gold nanoparticle (Au NP) decorated chemically reduced graphene oxide-P25 nanocomposite materials (CRGO-P25-Au NCMs) were prepared through a one-pot chemical reduction method. The nanocomposite materials were characterized using diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and electrochemical impedance spectroscopy (EIS) analyses. The performances of CRGO-P25-Au NCM modified ITO electrodes were evaluated towards the photoelectrochemical oxidation of methanol. The photoelectrode fabricated using CRGO-P25-Au NCM exhibited a higher photocurrent of 293 μA cm -2 compared to other control electrodes. The CRGO-P25-Au NCMs were also used for the photocatalytic reduction of highly toxic chromium(vi) ions to chromium(iii) ions in the presence of oxalic acid as a sacrificial electron donor. The results showed that around 75% of the Cr(vi) ions were photocatalytically reduced to Cr(iii) ions by the CRGO-P25-Au NCM within the light irradiation time of 1 h. In both applications, the enhanced catalytic activity of the CRGO-P25-Au NCM was attributed to the improved visible light absorption and the reduced charge recombination exerted by the interaction of CRGO and Au NPs with P25 and their synergistic effects.

Mathematical Modeling of the Effectiveness of Facemasks in Reducing the Spread of Novel Influenza A (H1N1)

PubMed Central

Tracht, Samantha M.; Del Valle, Sara Y.; Hyman, James M.

2010-01-01

On June 11, 2009, the World Health Organization declared the outbreak of novel influenza A (H1N1) a pandemic. With limited supplies of antivirals and vaccines, countries and individuals are looking at other ways to reduce the spread of pandemic (H1N1) 2009, particularly options that are cost effective and relatively easy to implement. Recent experiences with the 2003 SARS and 2009 H1N1 epidemics have shown that people are willing to wear facemasks to protect themselves against infection; however, little research has been done to quantify the impact of using facemasks in reducing the spread of disease. We construct and analyze a mathematical model for a population in which some people wear facemasks during the pandemic and quantify impact of these masks on the spread of influenza. To estimate the parameter values used for the effectiveness of facemasks, we used available data from studies on N95 respirators and surgical facemasks. The results show that if N95 respirators are only 20% effective in reducing susceptibility and infectivity, only 10% of the population would have to wear them to reduce the number of influenza A (H1N1) cases by 20%. We can conclude from our model that, if worn properly, facemasks are an effective intervention strategy in reducing the spread of pandemic (H1N1) 2009. PMID:20161764

History of Mathematics: Illuminating Understanding of School Mathematics Concepts for Prospective Mathematics Teachers

ERIC Educational Resources Information Center

Clark, Kathleen Michelle

2012-01-01

The use of the history of mathematics in teaching has long been considered a tool for enriching students' mathematical learning. However, in the USA few, if any, research efforts have investigated how the study of history of mathematics contributes to a person's mathematical knowledge for teaching. In this article, I present the results of…

Mathematics for Life: Sustainable Mathematics Education

ERIC Educational Resources Information Center

Renert, Moshe

2011-01-01

Ecological sustainability has not been a major focus of mathematics education research, even though it has attracted considerable attention in other areas of educational research in the past decade. The connections between mathematics education and ecological sustainability are not readily apparent. This paper explores how mathematics educators…

Mathematical modeling of tomographic scanning of cylindrically shaped test objects

NASA Astrophysics Data System (ADS)

Kapranov, B. I.; Vavilova, G. V.; Volchkova, A. V.; Kuznetsova, I. S.

2018-05-01

The paper formulates mathematical relationships that describe the length of the radiation absorption band in the test object for the first generation tomographic scan scheme. A cylindrically shaped test object containing an arbitrary number of standard circular irregularities is used to perform mathematical modeling. The obtained mathematical relationships are corrected with respect to chemical composition and density of the test object material. The equations are derived to calculate the resulting attenuation radiation from cobalt-60 isotope when passing through the test object. An algorithm to calculate the radiation flux intensity is provided. The presented graphs describe the dependence of the change in the γ-quantum flux intensity on the change in the radiation source position and the scanning angle of the test object.

A mathematical model for the interactive behavior of sulfate-reducing bacteria and methanogens during anaerobic digestion.

PubMed

Ahammad, S Ziauddin; Gomes, James; Sreekrishnan, T R

2011-09-01

Anaerobic degradation of waste involves different classes of microorganisms, and there are different types of interactions among them for substrates, terminal electron acceptors, and so on. A mathematical model is developed based on the mass balance of different substrates, products, and microbes present in the system to study the interaction between methanogens and sulfate-reducing bacteria (SRB). The performance of major microbial consortia present in the system, such as propionate-utilizing acetogens, butyrate-utilizing acetogens, acetoclastic methanogens, hydrogen-utilizing methanogens, and SRB were considered and analyzed in the model. Different substrates consumed and products formed during the process also were considered in the model. The experimental observations and model predictions showed very good prediction capabilities of the model. Model prediction was validated statistically. It was observed that the model-predicted values matched the experimental data very closely, with an average error of 3.9%.

Experimental Mathematics and Mathematical Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, David H.; Borwein, Jonathan M.; Broadhurst, David

2009-06-26

One of the most effective techniques of experimental mathematics is to compute mathematical entities such as integrals, series or limits to high precision, then attempt to recognize the resulting numerical values. Recently these techniques have been applied with great success to problems in mathematical physics. Notable among these applications are the identification of some key multi-dimensional integrals that arise in Ising theory, quantum field theory and in magnetic spin theory.

Abstraction in Mathematics and Mathematics Learning

ERIC Educational Resources Information Center

Mitchelmore, Michael; White, Paul

2004-01-01

It is claimed that, since mathematics is essentially a self-contained system, mathematical objects may best be described as "abstract-apart." On the other hand, fundamental mathematical ideas are closely related to the real world and their learning involves empirical concepts. These concepts may be called "abstract-general" because they embody…

Mathematical Modelling Approach in Mathematics Education

ERIC Educational Resources Information Center

Arseven, Ayla

2015-01-01

The topic of models and modeling has come to be important for science and mathematics education in recent years. The topic of "Modeling" topic is especially important for examinations such as PISA which is conducted at an international level and measures a student's success in mathematics. Mathematical modeling can be defined as using…

Mathematics Underground

ERIC Educational Resources Information Center

Luther, Kenneth H.

2012-01-01

Mathematical modeling of groundwater flow is a topic at the intersection of mathematics and geohydrology and is rarely encountered in undergraduate mathematics. However, this subject is full of interesting and meaningful examples of truly "applied" mathematics accessible to undergraduates, from the pre-calculus to advanced mathematics levels. This…

Chemical treatment costs reduced with use of in-pond raceway systems compared to traditional pond aquaculture

USDA-ARS?s Scientific Manuscript database

Production systems such as in-pond raceway systems (IPRS) and split ponds are providing an alternative to traditional pond culture for raising catfish in several southeastern states. One advantage noted by farmers utilizing these systems is the reduced cost associated with the chemical treatment of ...

Exploring mathematics anxiety and attitude: Mathematics students' experiences

NASA Astrophysics Data System (ADS)

Sahri, Nurul Ashikin; Kamaruzaman, Wan Nur Farahdalila Wan; Jamil, Jastini Mohd.; Shaharanee, Izwan Nizal Mohd.

2017-11-01

A quantitative and correlational, survey methods were used to investigate the relationships among mathematical anxiety and attitude toward student's mathematics performance. Participants were 100 students volunteer to enroll in undergraduate Industrial Statistics, Decision Sciences and Business Mathematics at one of northern university in Malaysia. Survey data consisted of demographic items and Likert scale items. The collected data was analyzed by using the idea of correlation and regression analysis. The results indicated that there was a significant positive relationship between students' attitude and mathematics anxiety. Results also indicated that a substantial positive effect of students' attitude and mathematics anxiety in students' achievement. Further study can be conducted on how mathematical anxiety and attitude toward mathematics affects can be used to predict the students' performance in the class.

A Capstone Mathematics Course for Prospective Secondary Mathematics Teachers

ERIC Educational Resources Information Center

Artzt, Alice F.; Sultan, Alan; Curcio, Frances R.; Gurl, Theresa

2012-01-01

This article describes an innovative capstone mathematics course that links college mathematics with school mathematics and pedagogy. It describes how college juniors in a secondary mathematics teacher preparation program engage in leadership experiences that enable them to learn mathematics for teaching while developing student-centered…

A mathematical model of a large open fire

NASA Technical Reports Server (NTRS)

Harsha, P. T.; Bragg, W. N.; Edelman, R. B.

1981-01-01

A mathematical model capable of predicting the detailed characteristics of large, liquid fuel, axisymmetric, pool fires is described. The predicted characteristics include spatial distributions of flame gas velocity, soot concentration and chemical specie concentrations including carbon monoxide, carbon dioxide, water, unreacted oxygen, unreacted fuel and nitrogen. Comparisons of the predictions with experimental values are also given.

Hands-On Mathematics: Two Cases from Ancient Chinese Mathematics

ERIC Educational Resources Information Center

Wang, Youjun

2009-01-01

In modern mathematical teaching, it has become increasingly emphasized that mathematical knowledge should be taught by problem-solving, hands-on activities, and interactive learning experiences. Comparing the ideas of modern mathematical education with the development of ancient Chinese mathematics, we find that the history of mathematics in…

On Mathematical Understanding: Perspectives of Experienced Chinese Mathematics Teachers

ERIC Educational Resources Information Center

Cai, Jinfa; Ding, Meixia

2017-01-01

Researchers have long debated the meaning of mathematical understanding and ways to achieve mathematical understanding. This study investigated experienced Chinese mathematics teachers' views about mathematical understanding. It was found that these mathematics teachers embrace the view that understanding is a web of connections, which is a result…

Molecular modeling: An open invitation for applied mathematics

NASA Astrophysics Data System (ADS)

Mezey, Paul G.

2013-10-01

Molecular modeling methods provide a very wide range of challenges for innovative mathematical and computational techniques, where often high dimensionality, large sets of data, and complicated interrelations imply a multitude of iterative approximations. The physical and chemical basis of these methodologies involves quantum mechanics with several non-intuitive aspects, where classical interpretation and classical analogies are often misleading or outright wrong. Hence, instead of the everyday, common sense approaches which work so well in engineering, in molecular modeling one often needs to rely on rather abstract mathematical constraints and conditions, again emphasizing the high level of reliance on applied mathematics. Yet, the interdisciplinary aspects of the field of molecular modeling also generates some inertia and perhaps too conservative reliance on tried and tested methodologies, that is at least partially caused by the less than up-to-date involvement in the newest developments in applied mathematics. It is expected that as more applied mathematicians take up the challenge of employing the latest advances of their field in molecular modeling, important breakthroughs may follow. In this presentation some of the current challenges of molecular modeling are discussed.

Theoretical Mathematics

NASA Astrophysics Data System (ADS)

Stöltzner, Michael

Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.

Exploring Differential Effects of Mathematics Courses on Mathematics Achievement

ERIC Educational Resources Information Center

Ma, Xin; McIntyre, Laureen J.

2005-01-01

Using data from the Longitudinal Study of Mathematics Participation (N = 1,518 students from 34 schools), we investigated the effects of pure and applied mathematics courses on mathematics achievement, controlling for prior mathematics achievement. Results of multilevel modelling showed that the effects of pure mathematics were significant after…

76 FR 41365 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 2A Chemical...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

...The Bureau of Industry and Security (BIS) is seeking public comments on the impact of amending the Chemical Weapons Convention Regulations (CWCR) to reduce the concentration level below which the CWCR exempt certain mixtures containing a Schedule 2A chemical from the declaration requirements that apply to Schedule 2A chemical production, processing, and consumption under the Chemical Weapons Convention (CWC). To make these declaration requirements consistent with the international agreement adopted by the Organization for the Prohibition of Chemical Weapons (OPCW), BIS is considering amending the CWCR to replace the current low concentration exemption (a concentration of ``less than 30%'' by volume or weight) with a two-tiered low concentration exemption that is based, in part, on whether the total amount of a Schedule 2A chemical produced, processed, or consumed at one or more plants on a plant site during a calendar year is less than the applicable verification threshold in the CWCR. Under this two- tiered approach, the declaration and reporting requirements in the CWCR would not apply to a chemical mixture containing a Schedule 2A chemical if: The concentration of the Schedule 2A chemical in the mixture is ``1% or less,'' or the concentration of the Schedule 2A chemical in the mixture is ``more than 1%, but less than or equal to 10%,'' and the annual amount of the Schedule 2A chemical produced, processed, or consumed is less than the relevant verification threshold. Legislative amendment of the Chemical Weapons Convention Implementation Act (CWCIA) is required in order to implement this proposed amendment to the CWCR. In addition, at U.S. national discretion, BIS is considering amending the CWCR to require declarations/reports for exports and imports of any mixtures that contain ``more than 10%'' of a Schedule 2A chemical by volume or weight (whichever method yields the lesser percentage), if the total quantity of the Schedule 2A chemical exported or imported

Pre-service Mathematics Teachers' Knowledge of History of Mathematics and Their Attitudes and Beliefs Towards Using History of Mathematics in Mathematics Education

NASA Astrophysics Data System (ADS)

Alpaslan, Mustafa; Işıksal, Mine; Haser, Çiğdem

2014-01-01

This study examined pre-service mathematics teachers' knowledge of history of mathematics and their attitudes and beliefs towards using history of mathematics in mathematics education based on year level in teacher education program and gender. The sample included 1,593 freshman, sophomore, junior, and senior pre-service middle school (grades 4-8) mathematics teachers from nine universities in Turkey. Data were collected through Knowledge of History of Mathematics Test and Attitudes and Beliefs towards the Use of History of Mathematics in Mathematics Education Questionnaire. Results indicate that pre-service teachers have moderate knowledge of history of mathematics and positive attitudes and beliefs towards using history of mathematics. Their knowledge scores increase as the year level in teacher education program advanced. Males' knowledge scores are significantly higher than females' scores in the first 2 years. This situation reverses in the last 2 years, but it is not statistically significant. Pre-service teachers have more positive attitudes and availing beliefs towards using history of mathematics as they progress in their teacher education program. Females have greater attitudes and beliefs mean scores than males in each of the years. The results indicate that the teacher education program may have enhanced the pre-service teachers' knowledge of history of mathematics by related courses. However, the moderate knowledge scores indicate that there is a need for revision of these courses. The pre-service teachers' positive attitudes and beliefs towards using history of mathematics stress the importance of teacher education program in order to prepare them for implementing this alternative strategy in the future.

Mathematics, the Computer, and the Impact on Mathematics Education.

ERIC Educational Resources Information Center

Tooke, D. James

2001-01-01

Discusses the connection between mathematics and the computer; mathematics curriculum; mathematics instruction, including teachers learning to use computers; and the impact of the computer on learning mathematics. (LRW)

Finite Mathematics and Discrete Mathematics: Is There a Difference?

ERIC Educational Resources Information Center

Johnson, Marvin L.

Discrete mathematics and finite mathematics differ in a number of ways. First, finite mathematics has a longer history and is therefore more stable in terms of course content. Finite mathematics courses emphasize certain particular mathematical tools which are useful in solving the problems of business and the social sciences. Discrete mathematics…

75 FR 15675 - Professional Research Experience Program in Chemical Science and Technology Laboratory...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-30

... in physics, chemistry, mathematics, computer science, or engineering. Institutions should have a 4..., mathematics, computer science, or engineering with work experiences in laboratories or other settings...-0141-01] Professional Research Experience Program in Chemical Science and Technology Laboratory...

Mathematical Intelligence and Mathematical Creativity: A Causal Relationship

ERIC Educational Resources Information Center

Tyagi, Tarun Kumar

2017-01-01

This study investigated the causal relationship between mathematical creativity and mathematical intelligence. Four hundred thirty-nine 8th-grade students, age ranged from 11 to 14 years, were included in the sample of this study by random cluster technique on which mathematical creativity and Hindi adaptation of mathematical intelligence test…

Examining the Efficacy of a Tier 2 Kindergarten Mathematics Intervention.

PubMed

Clarke, Ben; Doabler, Christian T; Smolkowski, Keith; Baker, Scott K; Fien, Hank; Strand Cary, Mari

2016-01-01

This study examined the efficacy of a Tier 2 kindergarten mathematics intervention program, ROOTS, focused on developing whole number understanding for students at risk in mathematics. A total of 29 classrooms were randomly assigned to treatment (ROOTS) or control (standard district practices) conditions. Measures of mathematics achievement were collected at pretest and posttest. Treatment and control students did not differ on mathematics assessments at pretest. Gain scores of at-risk intervention students were significantly greater than those of control peers, and the gains of at-risk treatment students were greater than the gains of peers not at risk, effectively reducing the achievement gap. Implications for Tier 2 mathematics instruction in a response to intervention (RtI) model are discussed. © Hammill Institute on Disabilities 2014.

Learning Mathematics for Teaching Mathematics: Non-Specialist Teachers' Mathematics Teacher Identity

ERIC Educational Resources Information Center

Crisan, Cosette; Rodd, Melissa

2017-01-01

A non-specialist teacher of mathematics is a school teacher who qualified to teach in a subject other than mathematics yet teaches mathematics to students in secondary school. There is an emerging interest internationally in this population, a brief report of which is given in the paper. Because of concerns about the quality of non-specialists'…

Mathematization Competencies of Pre-Service Elementary Mathematics Teachers in the Mathematical Modelling Process

ERIC Educational Resources Information Center

Yilmaz, Suha; Tekin-Dede, Ayse

2016-01-01

Mathematization competency is considered in the field as the focus of modelling process. Considering the various definitions, the components of the mathematization competency are determined as identifying assumptions, identifying variables based on the assumptions and constructing mathematical model/s based on the relations among identified…

Mathematical modeling of high-pH chemical flooding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhuyan, D.; Lake, L.W.; Pope, G.A.

1990-05-01

This paper describes a generalized compositional reservoir simulator for high-pH chemical flooding processes. This simulator combines the reaction chemistry associated with these processes with the extensive physical- and flow-property modeling schemes of an existing micellar/polymer flood simulator, UTCHEM. Application of the model is illustrated for cases from a simple alkaline preflush to surfactant-enhanced alkaline-polymer flooding.

Crossroads in the History of Mathematics and Mathematics Education. The Montana Mathematics Enthusiast: Monograph Series in Mathematics Education

ERIC Educational Resources Information Center

Sriraman, Bharath, Ed.

2012-01-01

The interaction of the history of mathematics and mathematics education has long been construed as an esoteric area of inquiry. Much of the research done in this realm has been under the auspices of the history and pedagogy of mathematics group. However there is little systematization or consolidation of the existing literature aimed at…

Methodology and Results of Mathematical Modelling of Complex Technological Processes

NASA Astrophysics Data System (ADS)

Mokrova, Nataliya V.

2018-03-01

The methodology of system analysis allows us to draw a mathematical model of the complex technological process. The mathematical description of the plasma-chemical process was proposed. The importance the quenching rate and initial temperature decrease time was confirmed for producing the maximum amount of the target product. The results of numerical integration of the system of differential equations can be used to describe reagent concentrations, plasma jet rate and temperature in order to achieve optimal mode of hardening. Such models are applicable both for solving control problems and predicting future states of sophisticated technological systems.

Chemical Terrorism: US Policies to Reduce the Chemical Terror Threat

DTIC Science & Technology

2008-09-01

In- stitute 1992-present CARLA HILLS US Trade Representative 1989-93 RICHARD HOLBROOKE Ambassador to UN, 1999-2001 THOMAS KEAN Governor New...Jersey 1982- 1990 ANTHONY LAKE National Security Advisor 1993-97 JOHN LEHMAN Secretary of the Navy 1981-87 RICHARD C. LEONE President, The...chemical, or biologi- cal, or nuclear weapons.” President George W. Bush, Remarks at the National Defense University, February 11, 2004. 3 “We must be

The Relationships among Mathematics Teaching Efficacy, Mathematics Self-Efficacy, and Mathematical Beliefs for Elementary Pre-Service Teachers

ERIC Educational Resources Information Center

Briley, Jason S.

2012-01-01

Ninety-five elementary pre-service teachers enrolled in a mathematics content course for elementary school teachers completed 3 surveys to measure mathematics teaching efficacy, mathematics self-efficacy, and mathematical beliefs. The pre-service teachers who reported stronger beliefs in their capabilities to teach mathematics effectively were…

Constructing Mathematical Knowledge: Epistemology and Mathematics Education. Studies in Mathematics Education Series: 4.

ERIC Educational Resources Information Center

Ernest, Paul, Ed.

This book illustrates the breadth of theoretical and philosophical perspectives that can be brought to bear on mathematics and education. Part 1, "Constructivism and the Learning of Mathematics," contains the following chapters: (1) "A Radical Constructivist View of Basic Mathematical Concepts" (E. von Glasersfeld); (2) "Interaction and Children's…

Symbolic Mathematics Engines in Teaching Chemistry: A Symposium Report

ERIC Educational Resources Information Center

Ellison, Mark

2004-01-01

The use of Symbolic Mathematics Engines (SMEs) in chemical education as a part of the Division of Computers in Chemistry was discussed by a panel of educators at the Symbolic Calculation in Chemistry symposium in Philadelphia in 2004. The panelists agreed that many more topics in chemistry are amenable to SME's exploration and that symbolic…

MATHEMATICAL MODELING OF OZONE ABSORPTION IN THE LOWER RESPIRATORY TRACT

EPA Science Inventory

A mathematical O3 dosimetry model has been developed for simulating the local absorption of O3 in the lower respiratory tract (LRT) of animals and man. The model takes into account LRT anatomy, transport in the lumen and air spaces, transport and chemical reactions in the liquid ...

Discrete Mathematics and the Secondary Mathematics Curriculum.

ERIC Educational Resources Information Center

Dossey, John

Discrete mathematics, the mathematics of decision making for finite settings, is a topic of great interest in mathematics education at all levels. Attention is being focused on resolving the diversity of opinion concerning the exact nature of the subject, what content the curriculum should contain, who should study that material, and how that…

Mathematics Self-Efficacy and Flow in Developmental Mathematics Students

ERIC Educational Resources Information Center

Golnabi, Laura

2017-01-01

This study examined mathematics self-efficacy and the characteristics of flow in the context of performing mathematical tasks. In particular, it explored the subjective experiences of 113 undergraduate students enrolled in a developmental mathematics course while they were independently solving certain mathematical problems. This study…

Cultural horizons for mathematics

NASA Astrophysics Data System (ADS)

Owens, Kay; Paraides, Patricia; Jannok Nutti, Ylva; Johansson, Gunilla; Bennet, Maria; Doolan, Pat; Peckham, Ray; Hill, John; Doolan, Frank; O'Sullivan, Dominic; Murray, Libbey; Logan, Patricia; McNair, Melissa; Sunnari, Vappu; Murray, Beatrice; Miller, Alissa; Nolan, John; Simpson, Alca; Ohrin, Christine; Doolan, Terry; Doolan, Michelle; Taylor, Paul

2011-06-01

As a result of a number of government reports, there have been numerous systemic changes in Indigenous education in Australia revolving around the importance of partnerships with the community. A forum with our local Dubbo community established the importance of working together and developed a model which placed the child in an ecological perspective that particularly noted the role of Elders and the place of the child in the family. However, there was also the issue of curriculum and mathematics education to be addressed. It was recognised that a colonised curriculum reduces the vision of what might be the potential for Indigenous mathematics education. This paper reports on the sharing that developed between our local community and some researchers and teachers from Sweden, Papua New Guinea and New Zealand. It has implications for recognising the impact of testing regimes, the teaching space, understanding the ways children learn, the curriculum, and teacher education. As a result of these discussions, a critical pedagogy that considers culture and place is presented as an ecocultural perspective on mathematics education. This perspective was seen as critical for the curriculum and learning experiences of Indigenous children.

More on Chemical Reaction Balancing.

ERIC Educational Resources Information Center

Swinehart, D. F.

1985-01-01

A previous article stated that only the matrix method was powerful enough to balance a particular chemical equation. Shows how this equation can be balanced without using the matrix method. The approach taken involves writing partial mathematical reactions and redox half-reactions, and combining them to yield the final balanced reaction. (JN)

Mathematical models of cell factories: moving towards the core of industrial biotechnology.

PubMed

Cvijovic, Marija; Bordel, Sergio; Nielsen, Jens

2011-09-01

Industrial biotechnology involves the utilization of cell factories for the production of fuels and chemicals. Traditionally, the development of highly productive microbial strains has relied on random mutagenesis and screening. The development of predictive mathematical models provides a new paradigm for the rational design of cell factories. Instead of selecting among a set of strains resulting from random mutagenesis, mathematical models allow the researchers to predict in silico the outcomes of different genetic manipulations and engineer new strains by performing gene deletions or additions leading to a higher productivity of the desired chemicals. In this review we aim to summarize the main modelling approaches of biological processes and illustrate the particular applications that they have found in the field of industrial microbiology. © 2010 The Authors. Journal compilation © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Mathematics, Anyone?

ERIC Educational Resources Information Center

Reys, Robert; Reys, Rustin

2011-01-01

In their dual roles as mathematics teachers and tennis coaches, the authors have worked with tennis players who have never thought about how a knowledge of mathematics might help them become "better" tennis players. They have also worked with many mathematics students who have never considered how much mathematics is associated with tennis. This…

Mathematical Selfies: Students' Real-World Mathematics

ERIC Educational Resources Information Center

Jaqua, Kathy M. C.

2017-01-01

The activity of snapping photographs to document all parts of daily life and sharing them with friends is the norm for many students. What if we could make mathematics as natural a part of daily life through "mathematical selfies"? The author's goal is to use students' love of selfies to help them see that mathematics is already part of…

Effects of Mathematics Anxiety and Mathematical Metacognition on Word Problem Solving in Children with and without Mathematical Learning Difficulties.

PubMed

Lai, Yinghui; Zhu, Xiaoshuang; Chen, Yinghe; Li, Yanjun

2015-01-01

Mathematics is one of the most objective, logical, and practical academic disciplines. Yet, in addition to cognitive skills, mathematical problem solving also involves affective factors. In the current study, we first investigated effects of mathematics anxiety (MA) and mathematical metacognition on word problem solving (WPS). We tested 224 children (116 boys, M = 10.15 years old, SD = 0.56) with the Mathematics Anxiety Scale for Children, the Chinese Revised-edition Questionnaire of Pupil's Metacognitive Ability in Mathematics, and WPS tasks. The results indicated that mathematical metacognition mediated the effect of MA on WPS after controlling for IQ. Second, we divided the children into four mathematics achievement groups including high achieving (HA), typical achieving (TA), low achieving (LA), and mathematical learning difficulty (MLD). Because mathematical metacognition and MA predicted mathematics achievement, we compared group differences in metacognition and MA with IQ partialled out. The results showed that children with MLD scored lower in self-image and higher in learning mathematics anxiety (LMA) than the TA and HA children, but not in mathematical evaluation anxiety (MEA). MLD children's LMA was also higher than that of their LA counterparts. These results provide insight into factors that may mediate poor WPS performance which emerges under pressure in mathematics. These results also suggest that the anxiety during learning mathematics should be taken into account in mathematical learning difficulty interventions.

Effects of Mathematics Anxiety and Mathematical Metacognition on Word Problem Solving in Children with and without Mathematical Learning Difficulties

PubMed Central

Lai, Yinghui; Zhu, Xiaoshuang; Chen, Yinghe; Li, Yanjun

2015-01-01

Mathematics is one of the most objective, logical, and practical academic disciplines. Yet, in addition to cognitive skills, mathematical problem solving also involves affective factors. In the current study, we first investigated effects of mathematics anxiety (MA) and mathematical metacognition on word problem solving (WPS). We tested 224 children (116 boys, M = 10.15 years old, SD = 0.56) with the Mathematics Anxiety Scale for Children, the Chinese Revised-edition Questionnaire of Pupil’s Metacognitive Ability in Mathematics, and WPS tasks. The results indicated that mathematical metacognition mediated the effect of MA on WPS after controlling for IQ. Second, we divided the children into four mathematics achievement groups including high achieving (HA), typical achieving (TA), low achieving (LA), and mathematical learning difficulty (MLD). Because mathematical metacognition and MA predicted mathematics achievement, we compared group differences in metacognition and MA with IQ partialled out. The results showed that children with MLD scored lower in self-image and higher in learning mathematics anxiety (LMA) than the TA and HA children, but not in mathematical evaluation anxiety (MEA). MLD children’s LMA was also higher than that of their LA counterparts. These results provide insight into factors that may mediate poor WPS performance which emerges under pressure in mathematics. These results also suggest that the anxiety during learning mathematics should be taken into account in mathematical learning difficulty interventions. PMID:26090806

International note: Are Emirati parents' attitudes toward mathematics linked to their adolescent children's attitudes toward mathematics and mathematics achievement?

PubMed

Areepattamannil, Shaljan; Khine, Myint Swe; Melkonian, Michael; Welch, Anita G; Al Nuaimi, Samira Ahmed; Rashad, Fatimah F

2015-10-01

Drawing on data from the 2012 Program for International Student Assessment (PISA) and employing multilevel modeling as an analytic strategy, this study examined the relations of adolescent children's perceptions of their parents' attitudes towards mathematics to their own attitudes towards mathematics and mathematics achievement among a sample of 5116 adolescents from 384 schools in the United Arab Emirates. The results of this cross-sectional study revealed that adolescents who perceived that their parents liked mathematics and considered mathematics was important for their children not only to study but also for their career tended to report higher levels of intrinsic and instrumental motivation to learn mathematics, mathematics self-concept and self-efficacy, and mathematics work ethic. Moreover, adolescents who perceived that their parents liked mathematics and considered mathematics was important for their children's career tended to report positive intentions and behaviors toward mathematics. However, adolescents who perceived that their parents considered mathematics was important for their children's career tended to report higher levels of mathematics anxiety. Finally, adolescents who perceived that their parents considered mathematics was important for their children to study performed significantly better on the mathematics assessment than did their peers whose parents disregarded the importance of learning mathematics. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

The Relationships among Pre-Service Mathematics Teachers' Beliefs about Mathematics, Mathematics Teaching, and Use of Technology in China

ERIC Educational Resources Information Center

Yang, Xinrong; Leung, Frederick K. S.

2015-01-01

This paper investigated pre-service mathematics teachers' mathematics beliefs, beliefs about information and communication technology (ICT), and their relationships. 787 pre-service mathematics teachers in China completed a survey questionnaire measuring their beliefs about the nature of mathematics, beliefs about mathematics learning and…

Mixtures Equation Pilot Program to Reduce Animal Testing

EPA Pesticide Factsheets

EPA is announcing the start of a pilot program to evaluate the usefulness and acceptability of a mathematical tool (the GHS Mixtures Equation), which is used in the Globally Harmonized System of Classification and Labeling of Chemicals (GHS).

Prospective Mathematics Teachers' Attitudes Towards Learning Mathematics with Technology

ERIC Educational Resources Information Center

Ipek, A. Sabri; Berigel, Muhammed; Albayrak, Mustafa

2007-01-01

Role of technology which is an important tool for new approaches in learning mathematics is rapidly increasing at focus point of learning mathematics with new designs. One of the biggest factors at learning and instructing technology based mathematic education is attitudes of mathematics teachers towards technology. At this study, attitudes of…

Pre-Service Teachers' Mathematics Self-Efficacy and Mathematics Teaching Self-Efficacy

ERIC Educational Resources Information Center

Zuya, Habila Elisha; Kwalat, Simon Kevin; Attah, Bala Galle

2016-01-01

Pre-service mathematics teachers' mathematics self-efficacy and mathematics teaching self-efficacy were investigated in this study. The purpose was to determine the confidence levels of their self-efficacy in mathematics and mathematics teaching. Also, the study was aimed at finding whether their mathematics self-efficacy and teaching…

Mathematics Teachers' Perceptions of Their Students' Mathematical Competence: Relations to Mathematics Achievement, Affect, and Engagement in Singapore and Australia

ERIC Educational Resources Information Center

Areepattamannil, Shaljan; Kaur, Berinderjeet

2013-01-01

This study, drawing on data from the Trends in International Mathematics and Science Study (TIMSS) 2011, examined whether mathematics teachers' perceptions of their students' mathematical competence were related to mathematics achievement, affect toward mathematics, and engagement in mathematics lessons among Grade 8 students in Singapore and…

Dynamic Boolean Mathematics

ERIC Educational Resources Information Center

Bossé, Michael J.; Adu-Gyamfi, Kwaku; Chandler, Kayla; Lynch-Davis, Kathleen

2016-01-01

Dynamic mathematical environments allow users to reify mathematical concepts through multiple representations, transform mathematical relations and organically explore mathematical properties, investigate integrated mathematics, and develop conceptual understanding. Herein, we integrate Boolean algebra, the functionalities of a dynamic…

Mathematical Modeling in Mathematics Education: Basic Concepts and Approaches

ERIC Educational Resources Information Center

Erbas, Ayhan Kürsat; Kertil, Mahmut; Çetinkaya, Bülent; Çakiroglu, Erdinç; Alacaci, Cengiz; Bas, Sinem

2014-01-01

Mathematical modeling and its role in mathematics education have been receiving increasing attention in Turkey, as in many other countries. The growing body of literature on this topic reveals a variety of approaches to mathematical modeling and related concepts, along with differing perspectives on the use of mathematical modeling in teaching and…

Using Mathematics in Science: Working with Your Mathematics Department

ERIC Educational Resources Information Center

Lyon, Steve

2014-01-01

Changes to the mathematics and science curriculums are designed to increase rigour in mathematics, and place greater emphasis on mathematical content in science subjects at key stages 3, 4 and 5 (ages 11-18). One way to meet the growing challenge of providing increased emphasis on mathematics in the science curriculum is greater collaboration…

Chemical Thromboprophylaxis Is Not Necessary to Reduce Risk of Thromboembolism With Tranexamic Acid After Total Hip Arthroplasty.

PubMed

Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

2017-02-01

The major concern with the use of tranexamic acid is that it may promote a hypercoagulable state and increase the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE), particularly when chemical thromboprophylaxis is not used. The objective of this study was to ascertain whether tranexamic acid reduces blood loss and transfusion amounts and increases the prevalence of DVT and PE in the patients undergoing primary cementless total hip arthroplasty (THA) without the use of routine chemical thromboprophylaxis. There were 480 patients (582 hips) in the control group who did not receive tranexamic acid and 487 patients (584 hips) in the study group who received tranexamic acid. Mechanical compression device was applied without any chemical thromboprophylaxis. Transfusion rates and volumes were recorded. DVT was diagnosed using both sonogram and venogram at 7 or 8 days postoperatively. All patients had pre- and postoperative perfusion lung scanning to defect pulmonary embolism (PE). Intraoperative (614 vs 389 mL) and postoperative blood loss (515 vs 329 mL) and transfusion volumes (3 units vs 1.5 units) were significantly lower (P < .001) in the tranexamic acid group. The prevalence of DVT was 15% (87 of 582 hips) in the control group and 18% (105 of 584 hips) in the tranexamic acid group. No fatal PE occurred in either group. The use of tranexamic acid reduces the volume of blood transfusion and does not increase the prevalence of DVT or PE in the patients who did not receive routine chemical thromboprophylaxis after primary cementless THA. Copyright © 2016 Elsevier Inc. All rights reserved.

Improving students’ mathematical representational ability through RME-based progressive mathematization

NASA Astrophysics Data System (ADS)

Warsito; Darhim; Herman, T.

2018-01-01

This study aims to determine the differences in the improving of mathematical representation ability based on progressive mathematization with realistic mathematics education (PMR-MP) with conventional learning approach (PB). The method of research is quasi-experiments with non-equivalent control group designs. The study population is all students of class VIII SMPN 2 Tangerang consisting of 6 classes, while the sample was taken two classes with purposive sampling technique. The experimental class is treated with PMR-MP while the control class is treated with PB. The instruments used are test of mathematical representation ability. Data analysis was done by t-test, ANOVA test, post hoc test, and descriptive analysis. The result of analysis can be concluded that: 1) there are differences of mathematical representation ability improvement between students treated by PMR-MP and PB, 2) no interaction between learning approach (PMR-MP, PB) and prior mathematics knowledge (PAM) to improve students’ mathematical representation; 3) Students’ mathematical representation improvement in the level of higher PAM is better than medium, and low PAM students. Thus, based on the process of mathematization, it is very important when the learning direction of PMR-MP emphasizes on the process of building mathematics through a mathematical model.

Promoting Mathematical Argumentation

ERIC Educational Resources Information Center

Rumsey, Chepina; Langrall, Cynthia W.

2016-01-01

The Standards for Mathematical Practice (SMP) in the Common Core State Standards for Mathematics (CCSSM) (CCSSI 2010) highlight the mathematical habits that educators should be fostering in mathematics classrooms throughout K-grade 12 education. That argumentation and discourse are important components of developing mathematically proficient…

Application of mathematical planning in production of filled emulsion rubbers

NASA Astrophysics Data System (ADS)

Pugacheva, I. N.; Molokanova, L. V.; Popova, L. V.; Repin, P. S.

2018-05-01

The applicability of mathematical planning of experiment in the field of chemistry and chemical engineering, in particular in the industrial production of synthetic rubbers, is considered in the article. Possibility of using secondary material resources, which are waste products of light industry, in the production of elastomeric compositions is studied. The method of obtaining a powdered cellulose additive from wastes containing cellulose fiber is described. The best way of introducing the obtained additive into elastomeric compositions based on the emulsion rubber is established. Optimal conditions for obtaining filled emulsion rubber with the help of a powdered cellulose additive were established basing on the mathematical planning of experiment.

Method for producing chemically bonded phosphate ceramics and for stabilizing contaminants encapsulated therein utilizing reducing agents

DOEpatents

Singh, Dileep; Wagh, Arun S.; Jeong, Seung-Young

2000-01-01

Known phosphate ceramic formulations are improved and the ability to produce iron-based phosphate ceramic systems is enabled by the addition of an oxidizing or reducing step during the acid-base reactions that form the phosphate ceramic products. The additives allow control of the rate of the acid-base reactions and concomitant heat generation. In an alternate embodiment, waste containing metal anions are stabilized in phosphate ceramic products by the addition of a reducing agent to the phosphate ceramic mixture. The reduced metal ions are more stable and/or reactive with the phosphate ions, resulting in the formation of insoluble metal species within the phosphate ceramic matrix, such that the resulting chemically bonded phosphate ceramic product has greater leach resistance.

Chemical Dosing and First-Order Kinetics

ERIC Educational Resources Information Center

Hladky, Paul W.

2011-01-01

College students encounter a variety of first-order phenomena in their mathematics and science courses. Introductory chemistry textbooks that discuss first-order processes, usually in conjunction with chemical kinetics or radioactive decay, stop at single, discrete dose events. Although single-dose situations are important, multiple-dose events,…

Effect of Using Mathematics Laboratory in Teaching Mathematics on the Achievement of Mathematics Students

ERIC Educational Resources Information Center

Okigbo, Ebele C.; Osuafor, Abigail M.

2008-01-01

The study investigated the effect of using mathematics laboratory in teaching on students' achievement in Junior Secondary School Mathematics. A total of 100 JS 3 Mathematics students were involved in the study. The study is a quasi-experimental research. Results were analyzed using mean, standard deviation and analysis of covariance (ANCOVA).…

Teaching Mathematics to Non-Mathematics Majors through Applications

ERIC Educational Resources Information Center

Abramovich, Sergei; Grinshpan, Arcadii Z.

2008-01-01

This article focuses on the important role of applications in teaching mathematics to students with career paths other than mathematics. These include the fields as diverse as education, engineering, business, and life sciences. Particular attention is given to instructional computing as a means for concept development in mathematics education…

Changing Our Perspective on Space: Place Mathematics as a Human Endeavour

ERIC Educational Resources Information Center

Owens, Kay

2010-01-01

This paper collates some of the systematic ways that different cultural groups refer to space. In some cases, space is more strongly identified in terms of place than in school Indo-European mathematics approaches. The affinity to place does not reduce the efficient, abstract, mathematical system behind the reference but it does strengthen its…

GENDER EQUALITY AND THE GENDER GAP IN MATHEMATICS.

PubMed

Tao, Hung-Lin; Michalopoulos, Christos

2018-03-01

A gender gap has been found in mathematics (boys outperform girls) that has prevailed across countries for many decades. Whether this gap results from nature or nurture has been hotly debated. Using the evidence of PISA 2003 and the gender equality index of 2003, some researchers have argued that an improvement in gender equality reduces the gender gap in mathematics. This study used five waves of country-level PISA data and, controlling for country fixed effects, found no evidence to support this argument. Furthermore, individual data for PISA 2012 and the multilevel data model were used. The conclusion drawn also does not support the argument. In fact, the relationship between gender equality and the gender gap in mathematics vanished after PISA 2003.

Detailed and reduced chemical-kinetic descriptions for hydrocarbon combustion

NASA Astrophysics Data System (ADS)

Petrova, Maria V.

Numerical and theoretical studies of autoignition processes of fuels such as propane are in need of realistic simplified chemical-kinetic descriptions that retain the essential features of the detailed descriptions. These descriptions should be computationally feasible and cost-effective. Such descriptions are useful for investigating ignition processes that occur, for example, in homogeneous-charge compression-ignition engines, for studying the structures and dynamics of detonations and in fields such as multi-dimensional Computational Fluid Dynamics (CFD). Reduced chemistry has previously been developed successfully for a number of other hydrocarbon fuels, however, propane has not been considered in this manner. This work focuses on the fuels of propane, as well propene, allene and propyne, for several reasons. The ignition properties of propane resemble those of other higher hydrocarbons but are different from those of the lower hydrocarbons (e.g. ethylene and acetylene). Propane, therefore, may be the smallest hydrocarbon that is representative of higher hydrocarbons in ignition and detonation processes. Since the overall activation energy and ignition times for propane are similar to those of other higher hydrocarbons, including liquid fuels that are suitable for many applications, propane has been used as a model fuel for several numerical and experimental studies. The reason for studying elementary chemistry of propene and C3H4 (allene or propyne) is that during the combustion process, propane breaks down to propene and C3H4 before proceeding to products. Similarly, propene combustion includes C3H4 chemistry. In studying propane combustion, it is therefore necessary to understand the underlying combustion chemistry of propene as well as C3H 4. The first part of this thesis focuses on obtaining and testing a detailed chemical-kinetic description for autoignition of propane, propene and C 3H4, by comparing predictions obtained with this detailed mechanism

Velocity encoding with the slice select refocusing gradient for faster imaging and reduced chemical shift-induced phase errors.

PubMed

Middione, Matthew J; Thompson, Richard B; Ennis, Daniel B

2014-06-01

To investigate a novel phase-contrast MRI velocity-encoding technique for faster imaging and reduced chemical shift-induced phase errors. Velocity encoding with the slice select refocusing gradient achieves the target gradient moment by time shifting the refocusing gradient, which enables the use of the minimum in-phase echo time (TE) for faster imaging and reduced chemical shift-induced phase errors. Net forward flow was compared in 10 healthy subjects (N = 10) within the ascending aorta (aAo), main pulmonary artery (PA), and right/left pulmonary arteries (RPA/LPA) using conventional flow compensated and flow encoded (401 Hz/px and TE = 3.08 ms) and slice select refocused gradient velocity encoding (814 Hz/px and TE = 2.46 ms) at 3 T. Improved net forward flow agreement was measured across all vessels for slice select refocused gradient compared to flow compensated and flow encoded: aAo vs. PA (1.7% ± 1.9% vs. 5.8% ± 2.8%, P = 0.002), aAo vs. RPA + LPA (2.1% ± 1.7% vs. 6.0% ± 4.3%, P = 0.03), and PA vs. RPA + LPA (2.9% ± 2.1% vs. 6.1% ± 6.3%, P = 0.04), while increasing temporal resolution (35%) and signal-to-noise ratio (33%). Slice select refocused gradient phase-contrast MRI with a high receiver bandwidth and minimum in-phase TE provides more accurate and less variable flow measurements through the reduction of chemical shift-induced phase errors and a reduced TE/repetition time, which can be used to increase the temporal/spatial resolution and/or reduce breath hold durations. Copyright © 2013 Wiley Periodicals, Inc.

Program Helps To Determine Chemical-Reaction Mechanisms

NASA Technical Reports Server (NTRS)

Bittker, D. A.; Radhakrishnan, K.

1995-01-01

General Chemical Kinetics and Sensitivity Analysis (LSENS) computer code developed for use in solving complex, homogeneous, gas-phase, chemical-kinetics problems. Provides for efficient and accurate chemical-kinetics computations and provides for sensitivity analysis for variety of problems, including problems involving honisothermal conditions. Incorporates mathematical models for static system, steady one-dimensional inviscid flow, reaction behind incident shock wave (with boundary-layer correction), and perfectly stirred reactor. Computations of equilibrium properties performed for following assigned states: enthalpy and pressure, temperature and pressure, internal energy and volume, and temperature and volume. Written in FORTRAN 77 with exception of NAMELIST extensions used for input.

Interest in mathematics and science among students having high mathematics aptitude

NASA Astrophysics Data System (ADS)

Ely, Jane Alice

The study investigates why men and women differ in their interest in mathematics and science and in the pursuit of careers in mathematics and science. The most persistent gender differential in educational standard testing is the scores in mathematics achievement. The mean Scholastic Aptitude Test (Mathematics) scores for women are consistently below that of men by about 40 points. One result of this gender differential in mathematics is that few women entertain a career requiring a robust knowledge of higher mathematics (i.e. engineering, computing, or the physical sciences). A large body of literature has been written attempting to explain why this is happening. Biological, cultural, structural and psychological explanations have been suggested and empirically examined. Controlling for mathematical ability is one method of sorting out these explanations. Eliminating mathematical ability as a factor, this dissertation reports the results of a study of men and women college students who all had high mathematics ability. Thus, any differences we found among them would have to be a result of other variables. Using a Mathematics Placement Exam and the SAT-M, forty-two students (12 males and 30 females) with high scores in both were interviewed. Student were asked about their experiences in high school and college mathematics, their career choices, and their attitudes toward mathematics. The findings, that there were no gender differences in the course selection, attitudes towards mathematics, and career choice, differed from my initial expectations. This negative finding suggests that women with high ability in mathematics are just as likely as men to pursue interests in mathematics and related courses in college and in selecting careers.

Facilitating Student Understanding of Buffering by an Integration of Mathematics and Chemical Concepts

ERIC Educational Resources Information Center

Curtright, Robert; Emry, Randall; Heaton, Ruth M.; Markwell, John

2004-01-01

We describe a simple undergraduate exercise involving the titration of a weak acid by a strong base using a pH meter and a micropipette. Students then use their data and carry out graphical analyses with a spreadsheet. The analyses involve using mathematical concepts such as first-derivative and semi-log plots and provide an opportunity for…

Mathematical thinking styles of undergraduate students and their achievement in mathematics

NASA Astrophysics Data System (ADS)

Risnanosanti

2017-08-01

The main purpose of this study is to analyze the role of mathematical thinking styles in students' achievement in mathematics. On the basis of this study, it is also to generate recommendation for classroom instruction. The two specific aims are; first to observe students' mathematical thinking styles during problem solving, the second to asses students' achievement in mathematics. The data were collected by using Mathematical Thinking Styles questionnaires and test of students' achievement in mathematics. The subject in this study was 35 students from third year at mathematics study program of Muhammadiyah University of Bengkulu in academic year 2016/2017. The result of this study was that the students have three mathematical thinking styles (analytic, visual, and integrated), and the students who have analytic styles have better achievement than those who have visual styles in mathematics.

Quotable Quotes in Mathematics

ERIC Educational Resources Information Center

Lo, Bruce W. N.

1983-01-01

As a way to dispel negative feelings toward mathematics, a variety of quotations are given. They are categorized by: what mathematics is, mathematicians, mathematics and other disciplines, different areas of mathematics, mathematics and humor, applications of mathematics, and pure versus applied mathematics. (MNS)

Mesoporous Silica Nanoparticle Delivery of Chemically Modified siRNA Against TWIST1 Leads to Reduced Tumor Burden

PubMed Central

Finlay, James; Roberts, Cai M.; Dong, Juyao; Zink, Jeffrey I.; Tamanoi, Fuyuhiko; Glackin, Carlotta A.

2015-01-01

Growth and progression of solid tumors depends on the integration of multiple pro-growth and survival signals, including the induction of angiogenesis. TWIST1 is a transcription factor whose reactivation in tumors leads to epithelial to mesenchymal transition (EMT), including increased cancer cell stemness, survival, and invasiveness. Additionally, TWIST1 drives angiogenesis via activation of IL-8 and CCL2, independent of VEGF signaling. In this work, results suggest that chemically modified siRNA against TWIST1 reverses EMT both in vitro and in vivo. siRNA delivery with a polyethyleneimine-coated mesoporous silica nanoparticle (MSN) led to reduction of TWIST1 target genes and migratory potential in vitro. In mice bearing xenograft tumors, weekly intravenous injections of the siRNA-nanoparticle complexes resulted in decreased tumor burden together with a loss of CCL2 suggesting a possible anti-angiogenic response. Therapeutic use of TWIST1 siRNA delivered via MSNs has the potential to inhibit tumor growth and progression in many solid tumor types. Chemically modified siRNA against TWIST1 was complexed to cation-coated mesoporous silica nanoparticles and tested in vitro and in vivo. In cell culture experiments, siRNA reduced expression of TWIST1 and its target genes, and reduced cell migration. In mice, injections of the siRNA-nanoparticle complex led to reduced tumor weight. Data suggest that diminished tumor burden was the result of reduced CCL2 expression and angiogenesis following TWIST1 knockdown. PMID:26115637

Elementary Mathematics Teachers' Perceptions and Lived Experiences on Mathematical Communication

ERIC Educational Resources Information Center

Kaya, Defne; Aydin, Hasan

2016-01-01

Mathematical thinking skills and meaningful mathematical understanding are among the goals of current mathematics education. There is a wide consensus among scholars about the purpose of developing mathematical understanding and higher order thinking skills in students. However, how to develop those skills in classroom settings is an area that…

Assessing Mathematics Self-Efficacy: How Many Categories Do We Really Need?

ERIC Educational Resources Information Center

Toland, Michael D.; Usher, Ellen L.

2016-01-01

The present study tested whether a reduced number of categories is optimal for assessing mathematics self-efficacy among middle school students using a 6-point Likert-type format or a 0- to 100-point format. Two independent samples of middle school adolescents (N = 1,913) were administered a 24-item Middle School Mathematics Self-Efficacy Scale…

History of Modern Applied Mathematics in Mathematics Education

ERIC Educational Resources Information Center

Jankvist, Uffe Thomas

2009-01-01

This article discusses the integration of history of modern applied mathematics in mathematics education as well as the possible teaching and learning benefits of introducing a newer history of mathematics over an old(er) one--something that seems to be done most often when integrating history. Three cases of the history of modern applied…

How students learn to coordinate knowledge of physical and mathematical models in cellular physiology

NASA Astrophysics Data System (ADS)

Lira, Matthew

This dissertation explores the Knowledge in Pieces (KiP) theory to account for how students learn to coordinate knowledge of mathematical and physical models in biology education. The KiP approach characterizes student knowledge as a fragmented collection of knowledge elements as opposed to stable and theory-like knowledge. This dissertation sought to use this theoretical lens to account for how students understand and learn with mathematical models and representations, such as equations. Cellular physiology provides a quantified discipline that leverages concepts from mathematics, physics, and chemistry to understand cellular functioning. Therefore, this discipline provides an exemplary context for assessing how biology students think and learn with mathematical models. In particular, the resting membrane potential provides an exemplary concept well defined by models of dynamic equilibrium borrowed from physics and chemistry. In brief, membrane potentials, or voltages, "rest" when the electrical and chemical driving forces for permeable ionic species are equal in magnitude but opposite in direction. To assess students' understandings of this concept, this dissertation employed three studies: the first study employed the cognitive clinical interview to assess student thinking in the absence and presence of equations. The second study employed an intervention to assess student learning and the affordances of an innovative assessment. The third student employed a human-computer-interaction paradigm to assess how students learn with a novel multi-representational technology. Study 1 revealed that students saw only one influence--the chemical gradient--and that students coordinated knowledge of only this gradient with the related equations. Study 2 revealed that students benefited from learning with the multi-representational technology and that the assessment detected performance gains across both calculation and explanation tasks. Last, Study 3 revealed how students

A screen of chemical modifications identifies position-specific modification by UNA to most potently reduce siRNA off-target effects

PubMed Central

Bramsen, Jesper B.; Pakula, Malgorzata M.; Hansen, Thomas B.; Bus, Claus; Langkjær, Niels; Odadzic, Dalibor; Smicius, Romualdas; Wengel, Suzy L.; Chattopadhyaya, Jyoti; Engels, Joachim W.; Herdewijn, Piet; Wengel, Jesper; Kjems, Jørgen

2010-01-01

Small interfering RNAs (siRNAs) are now established as the preferred tool to inhibit gene function in mammalian cells yet trigger unintended gene silencing due to their inherent miRNA-like behavior. Such off-target effects are primarily mediated by the sequence-specific interaction between the siRNA seed regions (position 2–8 of either siRNA strand counting from the 5′-end) and complementary sequences in the 3′UTR of (off-) targets. It was previously shown that chemical modification of siRNAs can reduce off-targeting but only very few modifications have been tested leaving more to be identified. Here we developed a luciferase reporter-based assay suitable to monitor siRNA off-targeting in a high throughput manner using stable cell lines. We investigated the impact of chemically modifying single nucleotide positions within the siRNA seed on siRNA function and off-targeting using 10 different types of chemical modifications, three different target sequences and three siRNA concentrations. We found several differently modified siRNAs to exercise reduced off-targeting yet incorporation of the strongly destabilizing unlocked nucleic acid (UNA) modification into position 7 of the siRNA most potently reduced off-targeting for all tested sequences. Notably, such position-specific destabilization of siRNA–target interactions did not significantly reduce siRNA potency and is therefore well suited for future siRNA designs especially for applications in vivo where siRNA concentrations, expectedly, will be low. PMID:20453030

Advanced Mathematical Thinking and Students' Mathematical Learning: Reflection from Students' Problem-Solving in Mathematics Classroom

ERIC Educational Resources Information Center

Sangpom, Wasukree; Suthisung, Nisara; Kongthip, Yanin; Inprasitha, Maitree

2016-01-01

Mathematical teaching in Thai tertiary education still employs traditional methods of explanation and the use of rules, formulae, and theories in order for students to memorize and apply to their mathematical learning. This results in students' inability to concretely learn, fully comprehend and understand mathematical concepts and practice. In…

Elementary Pre-Service Teachers' Mathematics Anxiety and Mathematics Teaching Anxiety

ERIC Educational Resources Information Center

Haciomeroglu, Guney

2014-01-01

The present study examined the structure of elementary pre-service teachers' mathematics anxiety and mathematics teaching anxiety by asking whether the two systems of anxiety are related. The Turkish Mathematics Anxiety Rating Scale Short Version and the Mathematics Teaching Anxiety Scale were administered to 260 elementary pre-service teachers.…

Studies in Mathematics, Volume XVI. Some Uses of Mathematics: A Source Book for Teachers and Students of School Mathematics.

ERIC Educational Resources Information Center

Bell, Max S., Ed.

This is a collection of articles dealing with mathematical applications for use by high school teachers and students. The articles are intended to illustrate several themes: (1) how mathematics is applied via construction of mathematical models; (2) the various types of activities in applied mathematics; (3) the role of pure mathematics in applied…

Bounds on stochastic chemical kinetic systems at steady state

NASA Astrophysics Data System (ADS)

Dowdy, Garrett R.; Barton, Paul I.

2018-02-01

The method of moments has been proposed as a potential means to reduce the dimensionality of the chemical master equation (CME) appearing in stochastic chemical kinetics. However, attempts to apply the method of moments to the CME usually result in the so-called closure problem. Several authors have proposed moment closure schemes, which allow them to obtain approximations of quantities of interest, such as the mean molecular count for each species. However, these approximations have the dissatisfying feature that they come with no error bounds. This paper presents a fundamentally different approach to the closure problem in stochastic chemical kinetics. Instead of making an approximation to compute a single number for the quantity of interest, we calculate mathematically rigorous bounds on this quantity by solving semidefinite programs. These bounds provide a check on the validity of the moment closure approximations and are in some cases so tight that they effectively provide the desired quantity. In this paper, the bounded quantities of interest are the mean molecular count for each species, the variance in this count, and the probability that the count lies in an arbitrary interval. At present, we consider only steady-state probability distributions, intending to discuss the dynamic problem in a future publication.

Mathematical Modelling of Bacterial Populations in Bio-remediation Processes

NASA Astrophysics Data System (ADS)

Vasiliadou, Ioanna A.; Vayenas, Dimitris V.; Chrysikopoulos, Constantinos V.

2011-09-01

An understanding of bacterial behaviour concerns many field applications, such as the enhancement of water, wastewater and subsurface bio-remediation, the prevention of environmental pollution and the protection of human health. Numerous microorganisms have been identified to be able to degrade chemical pollutants, thus, a variety of bacteria are known that can be used in bio-remediation processes. In this study the development of mathematical models capable of describing bacterial behaviour considered in bio-augmentation plans, such as bacterial growth, consumption of nutrients, removal of pollutants, bacterial transport and attachment in porous media, is presented. The mathematical models may be used as a guide in designing and assessing the conditions under which areas contaminated with pollutants can be better remediated.

Mathematical psychology.

PubMed

Batchelder, William H

2010-09-01

Mathematical psychology is a sub-field of psychology that started in the 1950s and has continued to grow as an important contributor to formal psychological theory, especially in the cognitive areas of psychology such as learning, memory, classification, choice response time, decision making, attention, and problem solving. In addition, there are several scientific sub-areas that were originated by mathematical psychologists such as the foundations of measurement, stochastic memory models, and psychologically motivated reformulations of expected utility theory. Mathematical psychology does not include all uses of mathematics and statistics in psychology, and indeed there is a long history of such uses especially in the areas of perception and psychometrics. What is most unique about mathematical psychology is its approach to theory construction. While accepting the behaviorist dictum that the data in psychology must be observable and replicable, mathematical models are specified in terms of unobservable formal constructs that can predict detailed aspects of data across multiple experimental and natural settings. By now almost all the substantive areas of cognitive and experimental psychology have formal mathematical models and theories, and many of these are due to researchers that identify with mathematical psychology. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

Mathematical marriages: intercourse between mathematics and Semiotic choice.

PubMed

Wagner, Roy

2009-04-01

This paper examines the interaction between Semiotic choices and the presentation and solution of a family of contemporary mathematical problems centred around the so-called 'stable marriage problem'. I investigate how a socially restrictive choice of signs impacts mathematical production both in terms of problem formation and of solutions. I further note how the choice of gendered language ends up constructing a reality, which duplicates the very structural framework that it imported into mathematical analysis in the first place. I go on to point out some semiotic lines of flight from this interlocking grip of mathematics and gendered language.

Reduce, Reuse, Recycle: Resources and Strategies for the Use of Writing Projects in Mathematics

ERIC Educational Resources Information Center

Latulippe, Joe; Latulippe, Christine

2014-01-01

As an often recommended but under-utilized pedagogical strategy, writing in mathematics has many benefits for students. However, creating and grading worthwhile writing projects can be more time-consuming than utilizing more traditional forms of assessment. This paper provides a concrete example of a writing project prompt, questions, directions,…

Random Signal Fluctuations Can Reduce Random Fluctuations in Regulated Components of Chemical Regulatory Networks

NASA Astrophysics Data System (ADS)

Paulsson, Johan; Ehrenberg, Måns

2000-06-01

Many intracellular components are present in low copy numbers per cell and subject to feedback control. We use chemical master equations to analyze a negative feedback system where species X and S regulate each other's synthesis with standard intracellular kinetics. For a given number of X-molecules, S-variation can be significant. We show that this signal noise does not necessarily increase X-variation as previously thought but, surprisingly, can be necessary to reduce it below a Poissonian limit. The principle resembles Stochastic Resonance in that signal noise improves signal detection.

Structural Equation Model to Validate: Mathematics-Computer Interaction, Computer Confidence, Mathematics Commitment, Mathematics Motivation and Mathematics Confidence

ERIC Educational Resources Information Center

Garcia-Santillán, Arturo; Moreno-Garcia, Elena; Escalera-Chávez, Milka E.; Rojas-Kramer, Carlos A.; Pozos-Texon, Felipe

2016-01-01

Most mathematics students show a definite tendency toward an attitudinal deficiency, which can be primarily understood as intolerance to the matter, affecting their scholar performance adversely. In addition, information and communication technologies have been gradually included within the process of teaching mathematics. Such adoption of…

Mathematical relationships between metrics of chemical bioaccumulation in fish.

PubMed

Mackay, Don; Arnot, Jon A; Gobas, Frank A P C; Powell, David E

2013-07-01

Five widely used metrics of bioaccumulation in fish are defined and discussed, namely the octanol-water partition coefficient (KOW ), bioconcentration factor (BCF), bioaccumulation factor (BAF), biomagnification factor (BMF), and trophic magnification factor (TMF). Algebraic relationships between these metrics are developed and discussed using conventional expressions for chemical uptake from water and food and first-order losses by respiration, egestion, biotransformation, and growth dilution. Two BCFs may be defined, namely as an equilibrium partition coefficient KFW or as a nonequilibrium BCFK in which egestion losses are included. Bioaccumulation factors are shown to be the product of the BCFK and a novel equilibrium multiplier M containing 2 ratios, namely, the diet-to-water concentration ratio and the ratio of uptake rate constants for respiration and dietary uptake. Biomagnification factors are shown to be proportional to the lipid-normalized ratio of the predator/prey values of BCFK and the ratio of the equilibrium multipliers. Relationships with TMFs are also discussed. The effects of chemical hydrophobicity, biotransformation, and growth are evaluated by applying the relationships to a range of illustrative chemicals of varying KOW in a linear 4-trophic-level food web with typical values for uptake and loss rate constants. The roles of respiratory and dietary intakes are demonstrated, and even slow rates of biotransformation and growth can significantly affect bioaccumulation. The BCFK s and the values of M can be regarded as the fundamental determinants of bioaccumulation and biomagnification in aquatic food webs. Analyzing data from food webs can be enhanced by plotting logarithmic lipid-normalized concentrations or fugacities as a linear function of trophic level to deduce TMFs. Implications for determining bioaccumulation by laboratory tests for regulatory purposes are discussed. Copyright © 2013 SETAC.

Between the Academic Mathematics and the Mathematics Education Worlds.

ERIC Educational Resources Information Center

Moreira, Candida Queiroz

1997-01-01

Investigated stresses confronted by Portuguese secondary mathematics teachers during the first semester in a master's course, Perspectives on Mathematics Education, noting how they negatively affected teachers' self-confidence and morale and discussing fundamental issues teachers addressed in bridging the academic mathematics and mathematics…

The materiality of mathematics: presenting mathematics at the blackboard.

PubMed

Greiffenhagen, Christian

2014-09-01

Sociology has been accused of neglecting the importance of material things in human life and the material aspects of social practices. Efforts to correct this have recently been made, with a growing concern to demonstrate the materiality of social organization, not least through attention to objects and the body. As a result, there have been a plethora of studies reporting the social construction and effects of a variety of material objects as well as studies that have explored the material dimensions of a diversity of practices. In different ways these studies have questioned the Cartesian dualism of a strict separation of 'mind' and 'body'. However, it could be argued that the idea of the mind as immaterial has not been entirely banished and lingers when it comes to discussing abstract thinking and reasoning. The aim of this article is to extend the material turn to abstract thought, using mathematics as a paradigmatic example. This paper explores how writing mathematics (on paper, blackboards, or even in the air) is indispensable for doing and thinking mathematics. The paper is based on video recordings of lectures in formal logic and investigates how mathematics is presented at the blackboard. The paper discusses the iconic character of blackboards in mathematics and describes in detail a number of inscription practices of presenting mathematics at the blackboard (such as the use of lines and boxes, the designation of particular regions for specific mathematical purposes, as well as creating an 'architecture' visualizing the overall structure of the proof). The paper argues that doing mathematics really is 'thinking with eyes and hands' (Latour 1986). Thinking in mathematics is inextricably interwoven with writing mathematics. © London School of Economics and Political Science 2014.

The Characterization of Cognitive Processes Involved in Chemical Kinetics Using a Blended Processing Framework

ERIC Educational Resources Information Center

Bain, Kinsey; Rodriguez, Jon-Marc G.; Moon, Alena; Towns, Marcy H.

2018-01-01

Chemical kinetics is a highly quantitative content area that involves the use of multiple mathematical representations to model processes and is a context that is under-investigated in the literature. This qualitative study explored undergraduate student integration of chemistry and mathematics during problem solving in the context of chemical…

Components of Mathematics Anxiety: Factor Modeling of the MARS30-Brief.

PubMed

Pletzer, Belinda; Wood, Guilherme; Scherndl, Thomas; Kerschbaum, Hubert H; Nuerk, Hans-Christoph

2016-01-01

Mathematics anxiety involves feelings of tension, discomfort, high arousal, and physiological reactivity interfering with number manipulation and mathematical problem solving. Several factor analytic models indicate that mathematics anxiety is rather a multidimensional than unique construct. However, the factor structure of mathematics anxiety has not been fully clarified by now. This issue shall be addressed in the current study. The Mathematics Anxiety Rating Scale (MARS) is a reliable measure of mathematics anxiety (Richardson and Suinn, 1972), for which several reduced forms have been developed. Most recently, a shortened version of the MARS (MARS30-brief) with comparable reliability was published. Different studies suggest that mathematics anxiety involves up to seven different factors. Here we examined the factor structure of the MARS30-brief by means of confirmatory factor analysis. The best model fit was obtained by a six-factor model, dismembering the known two general factors "Mathematical Test Anxiety" (MTA) and "Numerical Anxiety" (NA) in three factors each. However, a more parsimonious 5-factor model with two sub-factors for MTA and three for NA fitted the data comparably well. Factors were differentially susceptible to sex differences and differences between majors. Measurement invariance for sex was established.

Rainforest Mathematics

ERIC Educational Resources Information Center

Kilpatrick, Jeremy

2014-01-01

This paper addresses the contested way that ethnomathematics has sometimes been received by mathematicians and others and what that disagreement might suggest about issues in mathematics education; namely, (a) the relation of ethnomathematics to academic mathematics; (b) recent efforts to reform secondary school mathematics so that it prepares…

Quantum Chemistry in Great Britain: Developing a Mathematical Framework for Quantum Chemistry

NASA Astrophysics Data System (ADS)

Simões, Ana; Gavroglu, Kostas

By 1935 quantum chemistry was already delineated as a distinct sub-discipline due to the contributions of Fritz London, Walter Heitler, Friedrich Hund, Erich Hückel, Robert Mulliken, Linus Pauling, John van Vleck and John Slater. These people are credited with showing that the application of quantum mechanics to the solution of chemical problems was, indeed, possible, especially so after the introduction of a number of new concepts and the adoption of certain approximation methods. And though a number of chemists had started talking of the formation of theoretical or, even, mathematical chemistry, a fully developed mathematical framework of quantum chemistry was still wanting. The work of three persons in particular-of John E. Lennard-Jones, Douglas R. Hartree, and Charles Alfred Coulson-has been absolutely crucial in the development of such a framework. In this paper we shall discuss the work of these three researchers who started their careers in the Cambridge tradition of mathematical physics and who at some point of their careers all became professors of applied mathematics. We shall argue that their work consisted of decisive contributions to the development of such a mathematical framework for quantum chemistry.

UAH mathematical model of the variable polarity plasma ARC welding system calculation

NASA Technical Reports Server (NTRS)

Hung, R. J.

1994-01-01

Significant advantages of Variable Polarity Plasma Arc (VPPA) welding process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. A mathematical model is presented to analyze the VPPA welding process. Results of the mathematical model were compared with the experimental observation accomplished by the GDI team.

Applications of the Soave-Redlich-Kwong Equations of State Using Mathematic

NASA Astrophysics Data System (ADS)

Sun, Lanyi; Zhai, Cheng; Zhang, Hui

The application of the Peng-Robinson equations of state (PR EOS) using Matlab and Mathematic has already been demonstrated. In this paper, using Mathematic to solve Soave-Redlich-Kwong (SRK) EOS, as well as the estimation of pure component properties, plotting of vapor-liquid equilibrium (VLE) diagram and calculation of chemical equilibrium, is presented. First the SRK EOS is used to predict several pure-component properties, such as liquid and gas molar volumes for isobutane. The vapor-liquid isobaric diagram is then plotted for a binary mixture composed of n-pentane and n-hexane under the pressures of 2*10^5 and 8*10^5 Pa respectively.

Exploring Mathematical Capital: An Essential Construct for Mathematical Success?

ERIC Educational Resources Information Center

Baber, Marla Ann Lasswell

2017-01-01

In the United States students have traditionally struggled with mathematics. Many students leave the educational system with limited mathematical literacy that can adversely affect their success as a college student, a consumer and citizen. In turn, lack of mathematical literacy affects their socioeconomic status. Through improving their…

From Mathematical Reading to Mathematical Literacy

ERIC Educational Resources Information Center

Beaudine, Gregory

2018-01-01

If teachers have a deeper comprehension of their students' reading ability, it may lead to students' improved literacy and understanding of the subject. The account presented in this article of the author's growing interest in mathematical literacy specifically involves mathematical reading. This shift in interest began with a six-week…

Mathematical Modeling: Challenging the Figured Worlds of Elementary Mathematics

ERIC Educational Resources Information Center

Wickstrom, Megan H.

2017-01-01

This article is a report on a teacher study group that focused on three elementary teachers' perceptions of mathematical modeling in contrast to typical mathematics instruction. Through the theoretical lens of figured worlds, I discuss how mathematics instruction was conceptualized across the classrooms in terms of artifacts, discourse, and…

Mathematics Teachers' Ideas about Mathematical Models: A Diverse Landscape

ERIC Educational Resources Information Center

Bautista, Alfredo; Wilkerson-Jerde, Michelle H.; Tobin, Roger G.; Brizuela, Bárbara M.

2014-01-01

This paper describes the ideas that mathematics teachers (grades 5-9) have regarding mathematical models of real-world phenomena, and explores how teachers' ideas differ depending on their educational background. Participants were 56 United States in-service mathematics teachers. We analyzed teachers' written responses to three open-ended…

Enhancing Core Mathematics Courses

ERIC Educational Resources Information Center

Billings, Esther; Schlicker, Steven; Novotny, Karen; Tefera, Akalu

2004-01-01

The Departments of Mathematics and Statistics at Grand Valley State University are engaged in a project to address the mathematical preparation of all its majors, including prospective elementary and secondary mathematics teachers. In this article, we describe how the mathematics and mathematics education faculty in our mathematics department…

Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Randall S. Seright

2007-09-30

This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) formore » existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated

Mathematics and engineering in real life through mathematical competitions

NASA Astrophysics Data System (ADS)

More, M.

2018-02-01

We bring out an experience of organizing mathematical competitions that can be used as a medium to motivate the student and teacher minds in new directions of thinking. This can contribute to fostering research, innovation and provide a hands-on experience of mathematical concepts with the real world. Mathematical competitions can be used to build curiosity and give an understanding of mathematical applications in real life. Participation in the competition has been classified under four broad categories. Student can showcase their findings in various forms of expression like model, poster, soft presentation, animation, live performance, art and poetry. The basic focus of the competition is on using open source computation tools and modern technology, to emphasize the relationship of mathematical concepts with engineering applications in real life.

The relative importance of two different mathematical abilities to mathematical achievement.

PubMed

Nunes, Terezinha; Bryant, Peter; Barros, Rossana; Sylva, Kathy

2012-03-01

Two distinct abilities, mathematical reasoning and arithmetic skill, might make separate and specific contributions to mathematical achievement. However, there is little evidence to inform theory and educational practice on this matter. The aims of this study were (1) to assess whether mathematical reasoning and arithmetic make independent contributions to the longitudinal prediction of mathematical achievement over 5 years and (2) to test the specificity of this prediction. Data from Avon Longitudinal Study of Parents and Children (ALSPAC) were available on 2,579 participants for analyses of KS2 achievement and on 1,680 for the analyses of KS3 achievement. Hierarchical regression analyses were used to assess the independence and specificity of the contribution of mathematical reasoning and arithmetic skill to the prediction of achievement in KS2 and KS3 mathematics, science, and English. Age, intelligence, and working memory (WM) were controls in these analyses. Mathematical reasoning and arithmetic did make independent contributions to the prediction of mathematical achievement; mathematical reasoning was by far the stronger predictor of the two. These predictions were specific in so far as these measures were more strongly related to mathematics than to science or English. Intelligence and WM were non-specific predictors; intelligence contributed more to the prediction of science than of maths, and WM predicted maths and English equally well. There is clear justification for making a distinction between mathematical reasoning and arithmetic skills. The implication is that schools must plan explicitly to improve mathematical reasoning as well as arithmetic skills. ©2011 The British Psychological Society.

The Effect of Reducing the Weight of Homework Assignments on the Mathematics Achievement of Upper Level High School Students

ERIC Educational Resources Information Center

Ortiz, Craig R.

2017-01-01

Homework varies widely in importance among both teachers and students, as well as in subject areas. In mathematics, it is generally expected that it plays a critical role in students' understanding of mathematics and will be assigned daily. However, it is also understood that whether students take homework seriously can be difficult to ascertain.…

Mathematics for Language, Language for Mathematics

ERIC Educational Resources Information Center

Prochazkova, Lenka Tejkalova

2013-01-01

The author discusses the balance and mutual influence of the language of instruction and mathematics in the context of CLIL, Content and Language Integrated Learning. Different aspects of the relationship of language and Mathematics teaching and learning are discussed: the benefits of using a foreign language of instruction, as well as the…

Sex and mathematical background as predictors of anxiety and self-efficacy in mathematics.

PubMed

Lussier, G

1996-12-01

Anxiety and self-efficacy in mathematics as a function of sex and mathematical background were investigated. This study employed an ex post facto 2 x 2 factorial design in which sex and mathematical background were classification variables. It was predicted that men would report lower anxiety scores and higher self-efficacy scores than women and that students with a high mathematical background would report lower anxiety scores and higher self-efficacy scores than those with a low background in mathematics. An interaction between sex and mathematical background was also predicted. 51 subjects were given the revised Mathematics Anxiety Scale and the Mathematics Self-efficacy Scale. Results supported the hypotheses with respect to background in mathematics for anxiety in mathematics, and all of the hypotheses were supported for self-efficacy in mathematics.

Effects of Modern Educational Game Play on Attitudes towards Mathematics, Mathematics Self-Efficacy, and Mathematics Achievement

ERIC Educational Resources Information Center

Ritzhaupt, Albert; Higgins, Heidi; Allred, Beth

2011-01-01

This study investigated the effects of modern educational game playing on middle school students' attitudes towards mathematics, mathematics self-efficacy, and mathematics achievement. Two hundred twenty-five middle school students from four different Title 1 schools in two different counties in the southeastern United States were recruited.…

Mathematics Anxiety in Young Children: Concurrent and Longitudinal Associations with Mathematical Performance

ERIC Educational Resources Information Center

Vukovic, Rose K.; Kieffer, Michael J.; Bailey, Sean P.; Harari, Rachel R.

2013-01-01

This study explored mathematics anxiety in a longitudinal sample of 113 children followed from second to third grade. We examined how mathematics anxiety related to different types of mathematical performance concurrently and longitudinally and whether the relations between mathematics anxiety and mathematical performance differed as a function of…

Mathematics Lessons without ...

ERIC Educational Resources Information Center

Cross, Kath; Hibbs, John

2006-01-01

In the Association of Teachers of Mathematics (ATM) Easter conference, 2006, the authors presented a list of important aspects of mathematics lessons, recommended for students to have a positive attitude to mathematics and for teachers to acquire effective teaching. The following are discussed in detail: (1) Mathematics lessons without good…

Reduced chemical warfare agent sorption in polyurethane-painted surfaces via plasma-enhanced chemical vapor deposition of perfluoroalkanes.

PubMed

Gordon, Wesley O; Peterson, Gregory W; Durke, Erin M

2015-04-01

Perfluoralkalation via plasma chemical vapor deposition has been used to improve hydrophobicity of surfaces. We have investigated this technique to improve the resistance of commercial polyurethane coatings to chemicals, such as chemical warfare agents. The reported results indicate the surface treatment minimizes the spread of agent droplets and the sorption of agent into the coating. The improvement in resistance is likely due to reduction of the coating's surface free energy via fluorine incorporation, but may also have contributing effects from surface morphology changes. The data indicates that plasma-based surface modifications may have utility in improving chemical resistance of commercial coatings.

Ammonia gas sensors based on chemically reduced graphene oxide sheets self-assembled on Au electrodes

PubMed Central

2014-01-01

We present a useful ammonia gas sensor based on chemically reduced graphene oxide (rGO) sheets by self-assembly technique to create conductive networks between parallel Au electrodes. Negative graphene oxide (GO) sheets with large sizes (>10 μm) can be easily electrostatically attracted onto positive Au electrodes modified with cysteamine hydrochloride in aqueous solution. The assembled GO sheets on Au electrodes can be directly reduced into rGO sheets by hydrazine or pyrrole vapor and consequently provide the sensing devices based on self-assembled rGO sheets. Preliminary results, which have been presented on the detection of ammonia (NH3) gas using this facile and scalable fabrication method for practical devices, suggest that pyrrole-vapor-reduced rGO exhibits much better (more than 2.7 times with the concentration of NH3 at 50 ppm) response to NH3 than that of rGO reduced from hydrazine vapor. Furthermore, this novel gas sensor based on rGO reduced from pyrrole shows excellent responsive repeatability to NH3. Overall, the facile electrostatic self-assembly technique in aqueous solution facilitates device fabrication, the resultant self-assembled rGO-based sensing devices, with miniature, low-cost portable characteristics and outstanding sensing performances, which can ensure potential application in gas sensing fields. PMID:24917701

Mathematical Modelling in the Junior Secondary Years: An Approach Incorporating Mathematical Technology

ERIC Educational Resources Information Center

Lowe, James; Carter, Merilyn; Cooper, Tom

2018-01-01

Mathematical models are conceptual processes that use mathematics to describe, explain, and/or predict the behaviour of complex systems. This article is written for teachers of mathematics in the junior secondary years (including out-of-field teachers of mathematics) who may be unfamiliar with mathematical modelling, to explain the steps involved…

Dilemma in Teaching Mathematics

ERIC Educational Resources Information Center

Md Kamaruddin, Nafisah Kamariah; Md Amin, Zulkarnain

2012-01-01

The challenge in mathematics education is finding the best way to teach mathematics. When students learn the reasoning and proving in mathematics, they will be proficient in mathematics. Students must know mathematics before they can apply it. Symbolism and logic is the key to both the learning of mathematics and its effective application to…

Mathematics Teacher Candidates' Metaphors about the Concept of "Mathematics"

ERIC Educational Resources Information Center

Erdogan, Ahmet; Yazlik, Derya Ozlem; Erdik, Cengiz

2014-01-01

The main purpose of this study was to research mathematics teacher candidates' perceptions about the concept of "mathematics" through the use of metaphors. The research is conducted during 2012-2013 academic year, on a group of 111 mathematics teacher candidates at the Education Faculty of a University in Turkey. To collect the research…

Influences of Self-Perceived Competence in Mathematics and Positive Affect toward Mathematics on Mathematics Achievement of Adolescents in Singapore

ERIC Educational Resources Information Center

Areepattamannil, Shaljan; Kaur, Berinderjeet

2012-01-01

This study, drawing on data from the Trends in International Mathematics and Science Study (TIMSS) 2007, examined the influences of self-perceived competence in mathematics and positive affect toward mathematics on mathematics achievement of adolescents in Singapore. Ordinary least squares (OLS) regression analyses revealed the positive influences…

Disorder and Chaos: Developing and Teaching an Interdisciplinary Course on Chemical Dynamics

ERIC Educational Resources Information Center

Desjardins, Steven G.

2008-01-01

In this paper we describe an interdisciplinary course on dynamics that is appropriate for nonscience majors. This course introduces ideas about mathematical modeling using examples based on pendulums, chemical kinetics, and population dynamics. The unique emphasis for a nonmajors course is on chemical reactions as dynamical systems that do more…

Functioning Mathematically: 1

ERIC Educational Resources Information Center

Cain, David

2007-01-01

This article presents the first part of the closing address given by the author to the 2007 Association of Teachers of Mathematics (ATM) Easter conference at Loughborough. In his closing address, the author focuses on functioning mathematically as opposed to functional mathematics. His view of functional mathematics is that the focus is on someone…

Mathematics and Engineering in Real Life through Mathematical Competitions

ERIC Educational Resources Information Center

More, M.

2018-01-01

We bring out an experience of organizing mathematical competitions that can be used as a medium to motivate the student and teacher minds in new directions of thinking. This can contribute to fostering research, innovation and provide a hands-on experience of mathematical concepts with the real world. Mathematical competitions can be used to build…

Mathematical Fiction: Its Place in Secondary-School Mathematics Learning

ERIC Educational Resources Information Center

Padula, Janice

2005-01-01

This article contains a small selection of mathematical fiction chosen with the teaching of mathematics in secondary school in mind. However, an attempt is made to classify the works and provide a few ideas about how these items may be used by mathematics teachers, sometimes, but not necessarily, in collaboration with science and humanities…

Peirce's Philosophy of Mathematical Education: Fostering Reasoning Abilities for Mathematical Inquiry

ERIC Educational Resources Information Center

Campos, Daniel G.

2010-01-01

I articulate Charles S. Peirce's philosophy of mathematical education as related to his conception of mathematics, the nature of its method of inquiry, and especially, the reasoning abilities required for mathematical inquiry. The main thesis is that Peirce's philosophy of mathematical education primarily aims at fostering the development of the…

An Investigation of Mathematical Modeling with Pre-Service Secondary Mathematics Teachers

ERIC Educational Resources Information Center

Thrasher, Emily Plunkett

2016-01-01

The goal of this thesis was to investigate and enhance our understanding of what occurs while pre-service mathematics teachers engage in a mathematical modeling unit that is broadly based upon mathematical modeling as defined by the Common Core State Standards for Mathematics (National Governors Association Center for Best Practices & Council…

Chemical Computer Man: Chemical Agent Response Simulation (CARS). Technical report, January 1983-September 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, E.G.; Mioduszewski, R.J.

The Chemical Computer Man: Chemical Agent Response Simulation (CARS) is a computer model and simulation program for estimating the dynamic changes in human physiological dysfunction resulting from exposures to chemical-threat nerve agents. The newly developed CARS methodology simulates agent exposure effects on the following five indices of human physiological function: mental, vision, cardio-respiratory, visceral, and limbs. Mathematical models and the application of basic pharmacokinetic principles were incorporated into the simulation so that for each chemical exposure, the relationship between exposure dosage, absorbed dosage (agent blood plasma concentration), and level of physiological response are computed as a function of time. CARS,more » as a simulation tool, is designed for the users with little or no computer-related experience. The model combines maximum flexibility with a comprehensive user-friendly interactive menu-driven system. Users define an exposure problem and obtain immediate results displayed in tabular, graphical, and image formats. CARS has broad scientific and engineering applications, not only in technology for the soldier in the area of Chemical Defense, but also in minimizing animal testing in biomedical and toxicological research and the development of a modeling system for human exposure to hazardous-waste chemicals.« less

Reduced biological control and enhanced chemical pest management in the evolution of fungus farming in ants

PubMed Central

Fernández-Marín, Hermógenes; Zimmerman, Jess K.; Nash, David R.; Boomsma, Jacobus J.; Wcislo, William T.

2009-01-01

To combat disease, most fungus-growing ants (Attini) use antibiotics from mutualistic bacteria (Pseudonocardia) that are cultured on the ants' exoskeletons and chemical cocktails from exocrine glands, especially the metapleural glands (MG). Previous work has hypothesized that (i) Pseudonocardia antibiotics are narrow-spectrum and control a fungus (Escovopsis) that parasitizes the ants' fungal symbiont, and (ii) MG secretions have broad-spectrum activity and protect ants and brood. We assessed the relative importance of these lines of defence, and their activity spectra, by scoring abundance of visible Pseudonocardia for nine species from five genera and measuring rates of MG grooming after challenging ants with disease agents of differing virulence. Atta and Sericomyrmex have lost or greatly reduced the abundance of visible bacteria. When challenged with diverse disease agents, including Escovopsis, they significantly increased MG grooming rates and expanded the range of targets. By contrast, species of Acromyrmex and Trachymyrmex maintain abundant Pseudonocardia. When challenged, these species had lower MG grooming rates, targeted primarily to brood. More elaborate MG defences and reduced reliance on mutualistic Pseudonocardia are correlated with larger colony size among attine genera, raising questions about the efficacy of managing disease in large societies with chemical cocktails versus bacterial antimicrobial metabolites. PMID:19324734

A Conceptual Model of Mathematical Reasoning for School Mathematics

ERIC Educational Resources Information Center

Jeannotte, Doris; Kieran, Carolyn

2017-01-01

The development of students' mathematical reasoning (MR) is a goal of several curricula and an essential element of the culture of the mathematics education research community. But what mathematical reasoning consists of is not always clear; it is generally assumed that everyone has a sense of what it is. Wanting to clarify the elements of MR,…

Components of Mathematics Anxiety: Factor Modeling of the MARS30-Brief

PubMed Central

Pletzer, Belinda; Wood, Guilherme; Scherndl, Thomas; Kerschbaum, Hubert H.; Nuerk, Hans-Christoph

2016-01-01

Mathematics anxiety involves feelings of tension, discomfort, high arousal, and physiological reactivity interfering with number manipulation and mathematical problem solving. Several factor analytic models indicate that mathematics anxiety is rather a multidimensional than unique construct. However, the factor structure of mathematics anxiety has not been fully clarified by now. This issue shall be addressed in the current study. The Mathematics Anxiety Rating Scale (MARS) is a reliable measure of mathematics anxiety (Richardson and Suinn, 1972), for which several reduced forms have been developed. Most recently, a shortened version of the MARS (MARS30-brief) with comparable reliability was published. Different studies suggest that mathematics anxiety involves up to seven different factors. Here we examined the factor structure of the MARS30-brief by means of confirmatory factor analysis. The best model fit was obtained by a six-factor model, dismembering the known two general factors “Mathematical Test Anxiety” (MTA) and “Numerical Anxiety” (NA) in three factors each. However, a more parsimonious 5-factor model with two sub-factors for MTA and three for NA fitted the data comparably well. Factors were differentially susceptible to sex differences and differences between majors. Measurement invariance for sex was established. PMID:26924996

Grounded Blends and Mathematical Gesture Spaces: Developing Mathematical Understandings via Gestures

ERIC Educational Resources Information Center

Yoon, Caroline; Thomas, Michael O. J.; Dreyfus, Tommy

2011-01-01

This paper examines how a person's gesture space can become endowed with mathematical meaning associated with mathematical spaces and how the resulting mathematical gesture space can be used to communicate and interpret mathematical features of gestures. We use the theory of grounded blends to analyse a case study of two teachers who used gestures…

Some unsolved problems in discrete mathematics and mathematical cybernetics

NASA Astrophysics Data System (ADS)

Korshunov, Aleksei D.

2009-10-01

There are many unsolved problems in discrete mathematics and mathematical cybernetics. Writing a comprehensive survey of such problems involves great difficulties. First, such problems are rather numerous and varied. Second, they greatly differ from each other in degree of completeness of their solution. Therefore, even a comprehensive survey should not attempt to cover the whole variety of such problems; only the most important and significant problems should be reviewed. An impersonal choice of problems to include is quite hard. This paper includes 13 unsolved problems related to combinatorial mathematics and computational complexity theory. The problems selected give an indication of the author's studies for 50 years; for this reason, the choice of the problems reviewed here is, to some extent, subjective. At the same time, these problems are very difficult and quite important for discrete mathematics and mathematical cybernetics. Bibliography: 74 items.

Mathematical Modeling of Protein Misfolding Mechanisms in Neurological Diseases: A Historical Overview.

PubMed

Carbonell, Felix; Iturria-Medina, Yasser; Evans, Alan C

2018-01-01

Protein misfolding refers to a process where proteins become structurally abnormal and lose their specific 3-dimensional spatial configuration. The histopathological presence of misfolded protein (MP) aggregates has been associated as the primary evidence of multiple neurological diseases, including Prion diseases, Alzheimer's disease, Parkinson's disease, and Creutzfeldt-Jacob disease. However, the exact mechanisms of MP aggregation and propagation, as well as their impact in the long-term patient's clinical condition are still not well understood. With this aim, a variety of mathematical models has been proposed for a better insight into the kinetic rate laws that govern the microscopic processes of protein aggregation. Complementary, another class of large-scale models rely on modern molecular imaging techniques for describing the phenomenological effects of MP propagation over the whole brain. Unfortunately, those neuroimaging-based studies do not take full advantage of the tremendous capabilities offered by the chemical kinetics modeling approach. Actually, it has been barely acknowledged that the vast majority of large-scale models have foundations on previous mathematical approaches that describe the chemical kinetics of protein replication and propagation. The purpose of the current manuscript is to present a historical review about the development of mathematical models for describing both microscopic processes that occur during the MP aggregation and large-scale events that characterize the progression of neurodegenerative MP-mediated diseases.

Educational standardization and gender differences in mathematics achievement: A comparative study.

PubMed

Ayalon, Hanna; Livneh, Idit

2013-03-01

We argue that between-country variations in the gender gap in mathematics are related to the level of educational system standardization. In countries with standardized educational systems both genders are exposed to similar knowledge and are motivated to invest in studying mathematics, which leads to similar achievements. We hypothesize that national examinations and between-teacher uniformity in covering major mathematics topics are associated with a smaller gender gap in a country. Based on Trends of International Mathematical and Science Study (TIMSS) 2003, we use multilevel regression models to compare the link of these two factors to the gender gap in 32 countries, controlling for various country characteristics. The use of national examinations and less between-teacher instructional variation prove major factors in reducing the advantage of boys over girls in mathematics scores and in the odds of excelling. Factors representing gender stratification, often analyzed in comparative gender-gap research in mathematics, are at most marginal in respect of the gap. Copyright © 2012 Elsevier Inc. All rights reserved.

Secondary Defense Chemicals in Milkweed Reduce Parasite Infection in Monarch Butterflies, Danaus plexippus.

PubMed

Gowler, Camden D; Leon, Kristoffer E; Hunter, Mark D; de Roode, Jacobus C

2015-06-01

In tri-trophic systems, herbivores may benefit from their host plants in fighting parasitic infections. Plants can provide parasite resistance in two contrasting ways: either directly, by interfering with the parasite, or indirectly, by increasing herbivore immunity or health. In monarch butterflies, the larval diet of milkweed strongly influences the fitness of a common protozoan parasite. Toxic secondary plant chemicals known as cardenolides correlate strongly with parasite resistance of the host, with greater cardenolide concentrations in the larval diet leading to lower parasite growth. However, milkweed cardenolides may covary with other indices of plant quality including nutrients, and a direct experimental link between cardenolides and parasite performance has not been established. To determine if the anti-parasitic activity of milkweeds is indeed due to secondary chemicals, as opposed to nutrition, we supplemented the diet of infected and uninfected monarch larvae with milkweed latex, which contains cardenolides but no nutrients. Across three experiments, increased dietary cardenolide concentrations reduced parasite growth in infected monarchs, which consequently had longer lifespans. However, uninfected monarchs showed no differences in lifespan across treatments, confirming that cardenolide-containing latex does not increase general health. Our results suggest that cardenolides are a driving force behind plant-derived resistance in this system.

Mathematics and Sports. Mathematical World. Volume 3.

ERIC Educational Resources Information Center

Sadovskii, L. E.; Sadovskii, A. L.

This volume contains some examples of mathematical applications in sports. Sports discussed include tennis, figure skating, gymnastics, track and field, soccer, skiing, hockey, and swimming. Problems and situations are posed and answers with thorough explanations are provided. Chapters include: (1) Mathematics and Sports; (2) What Is Applied…

Strategic of Applying Free Chemical Usage In Purified Water System For Pharmaceutical Industry Toward CPOB (Cara Pembuatan Obat yang Baik) Indonesia To Reducing Environmental Pollution

NASA Astrophysics Data System (ADS)

Kartono, R.; Basuki, Y. T.

2014-03-01

The purpose of this paper is to examine the sets of model and literature review to prove that strategy of applying free chemical usage in purified water system for pharmaceutical industry would be help the existing and new pharmaceutical companies to comply with part of Natioanal Agency of Drug and Food Control / Badan Pengawas Obat dan Makanan (NADFC/BPOM) regulation in order to achieve "Cara Pembuatan Obat yang Baik" (CPOB) of Indonesia pharmaceutical industry. One of the main reasons is when we figured out the number of Indonesian pharmaceutical industries in 2012 are kept reducing compare to the increasing numbers of Indonesian population growth. This strategy concept also might help the industries to reducing environmental pollution, and operational cost in pharmaceutical industries, by reducing of the chemical usage for water treatment process in floculation and cougulation and chlorination for sterillization. This new model is free usage of chemicals for purified water generation system process and sterilization. The concept offering of using membrane technology- Reverse Osmosis (RO) membrane base treatment to replace traditional chemical base treatment, following enhance Electrodeionization (EDI) as final polisher for controlling conductivity, and finally Ultra Violet (UV) disinfectant technology as final guard for bacteria controls instead of chemical base system in purified water generation system.

Chemical Equilibrium and Polynomial Equations: Beware of Roots.

ERIC Educational Resources Information Center

Smith, William R.; Missen, Ronald W.

1989-01-01

Describes two easily applied mathematical theorems, Budan's rule and Rolle's theorem, that in addition to Descartes's rule of signs and intermediate-value theorem, are useful in chemical equilibrium. Provides examples that illustrate the use of all four theorems. Discusses limitations of the polynomial equation representation of chemical…

Mathematical Creativity and Mathematical Aptitude: A Cross-Lagged Panel Analysis

ERIC Educational Resources Information Center

Tyagi, Tarun Kumar

2016-01-01

Cross-lagged panel correlation (CLPC) analysis has been used to identify causal relationships between mathematical creativity and mathematical aptitude. For this study, 480 8th standard students were selected through a random cluster technique from 9 intermediate and high schools of Varanasi, India. Mathematical creativity and mathematical…

Mathematical Models of Elementary Mathematics Learning and Performance. Final Report.

ERIC Educational Resources Information Center

Suppes, Patrick

This project was concerned with the development of mathematical models of elementary mathematics learning and performance. Probabilistic finite automata and register machines with a finite number of registers were developed as models and extensively tested with data arising from the elementary-mathematics strand curriculum developed by the…

Adults' Use of Mathematics and Its Influence on Mathematical Competence

ERIC Educational Resources Information Center

Duchhardt, Christoph; Jordan, Anne-Katrin; Ehmke, Timo

2017-01-01

The Programme for the International Assessment of Adult Competencies (PIAAC) has recently drawn additional attention to "mathematical literacy" as an important influential factor for individuals' life chances. High levels of mathematical literacy have thereby been linked to using mathematics in daily and working life frequently. In this…

Mathematics Coursework Regulates Growth in Mathematics Achievement

ERIC Educational Resources Information Center

Ma, Xin; Wilkins, Jesse L. M.

2007-01-01

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

The Mathematics and Mathematical Thinking of Seamstresses.

ERIC Educational Resources Information Center

Hancock, Sabrina J. C.

This study documents the mathematics practiced by four women in the context of sewing. The study describes the mathematics recognized in the skills, thinking and strategies used by the seamstresses. Through their work, the seamstresses exhibited an understanding of the concepts of angles, direction, parallel, reflection, symmetry, proportion,…

Evidence for Shared Genetic Risk between ADHD Symptoms and Reduced Mathematics Ability: A Twin Study

ERIC Educational Resources Information Center

Greven, Corina U.; Kovas, Yulia; Willcutt, Erik G.; Petrill, Stephen A.; Plomin, Robert

2013-01-01

Background: Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Methods: Data came from more than 6,000 twelve-year-old twin pairs from the UK population-representative Twins Early Development Study. Parents…

A synthesis of mathematical and cognitive performances of students with mathematics learning disabilities.

PubMed

Shin, Mikyung; Bryant, Diane Pedrotty

2015-01-01

The purpose of this study was to synthesize the findings from 23 articles that compared the mathematical and cognitive performances of students with mathematics learning disabilities (LD) to (a) students with LD in mathematics and reading, (b) age- or grade-matched students with no LD, and (c) mathematical-ability-matched younger students with no LD. Overall results revealed that students with mathematics LD exhibited higher word problem-solving abilities and no significant group differences on working memory, long-term memory, and metacognition measures compared to students with LD in mathematics and reading. Findings also revealed students with mathematics LD demonstrated significantly lower performance compared to age- or grade-matched students with no LD on both mathematical and cognitive measures. Comparison between students with mathematics LD and younger students with no LD revealed mixed outcomes on mathematical measures and generally no significant group differences on cognitive measures. © Hammill Institute on Disabilities 2013.

Causal Connections between Mathematical Language and Mathematical Knowledge: A Dialogic Reading Intervention

ERIC Educational Resources Information Center

Purpura, David J.; Napoli, Amy R.; Wehrspann, Elizabeth A.; Gold, Zachary S.

2017-01-01

The acquisition of early mathematical knowledge is critical for successful long-term academic development. Mathematical language is one of the strongest predictors of children's early mathematical success. Findings from previous studies have provided correlational evidence supporting the importance of mathematical language to the development of…

The Mathematics Education Debates: Preparing Students to Become Professionally Active Mathematics Teachers

ERIC Educational Resources Information Center

Munakata, Mika

2010-01-01

The Mathematics Education Debate is an assignment designed for and implemented in an undergraduate mathematics methods course for prospective secondary school mathematics teachers. For the assignment, students read and analyze current research and policy reports related to mathematics education, prepare and present their positions, offer…

Revealing and Capitalising on Young Children's Mathematical Potential

ERIC Educational Resources Information Center

English, Lyn D.

2016-01-01

With ongoing concerns about environments that push teachers toward increasingly structured assessments, thus reducing opportunities to observe young learners' mathematical capabilities, the publication of this special issue on formative assessment is especially significant and timely. The articles illustrate how we cannot rely solely on…

Mathematical Thinking and Creativity through Mathematical Problem Posing and Solving

ERIC Educational Resources Information Center

Ayllón, María F.; Gómez, Isabel A.; Ballesta-Claver, Julio

2016-01-01

This work shows the relationship between the development of mathematical thinking and creativity with mathematical problem posing and solving. Creativity and mathematics are disciplines that do not usually appear together. Both concepts constitute complex processes sharing elements, such as fluency (number of ideas), flexibility (range of ideas),…

Mathematical Writing Errors in Expository Writings of College Mathematics Students

ERIC Educational Resources Information Center

Guce, Ivee K.

2017-01-01

Despite the efforts to confirm the effectiveness of writing in learning mathematics, analysis on common errors in mathematical writings has not received sufficient attention. This study aimed to provide an account of the students' procedural explanations in terms of their commonly committed errors in mathematical writing. Nine errors in…

"Mathematics Is Like a Lion": Elementary Students' Beliefs about Mathematics

ERIC Educational Resources Information Center

Markovits, Zvia; Forgasz, Helen

2017-01-01

The aim of this study was to explore the beliefs of elementary school students about mathematics and about themselves as mathematics learners. The participants, Israeli grade 4 and grade 6 students, completed questionnaires. Using an "animal metaphor" to tap beliefs, some students perceived mathematics as difficult and complicated, while…

Authenticity of Mathematical Modeling

ERIC Educational Resources Information Center

Tran, Dung; Dougherty, Barbara J.

2014-01-01

Some students leave high school never quite sure of the relevancy of the mathematics they have learned. They fail to see links between school mathematics and the mathematics of everyday life that requires thoughtful decision making and often complex problem solving. Is it possible to bridge the gap between school mathematics and the mathematics in…

Pre-Service Secondary Mathematics Teachers' Reflections on Good and Bad Mathematics Teaching

ERIC Educational Resources Information Center

Dayal, Hem Chand

2013-01-01

Researchers suggest that teachers' beliefs about teaching are strongly influenced by their personal experiences with mathematics. This study aimed to explore Pacific Island pre-service secondary mathematics teachers' perceptions about good and bad mathematics teachers. Thirty pre-service teachers, enrolled in a mathematics teaching methods course…

Utilization of mathematics amongst healthcare students towards problem solving during their occupational safety health internship

NASA Astrophysics Data System (ADS)

Umasenan a/l Thanikasalam

2017-05-01

Occupational safety health is a multidisciplinary discipline concentrating on the safety, health and welfare of workers in the working place. Healthcare Students undergoing Occupational Safety Health internships are required to apply mathematical in areas such as safety legislation, safety behavior, ergonomics, chemical safety, OSH practices, industrial hygiene, risk management and safety health practices as problem solving. The aim of this paper is to investigate the level of mathematics and logic utilization from these students during their internship looking at areas of Hazard identification, Determining the population exposed to the hazard, Assessing the risk of the exposure to the hazards and Taking preventive and control. A total of 142 returning healthcare students from their Occupational Safety Health, internship were given a questionnaire to measure their perceptions towards mathematical and logic utilization. The overall results indicated a strong positive skewed result towards the use of Mathematics during their internship. The findings showed that mathematics were well delivered by the students during their internship. Mathematics could not be separated from OSH practice as a needed precision in quantifying safety, health an d welfare of workers in addition to empiricism.

Combining in situ chemical oxidation, stabilization, and anaerobic bioremediation in a single application to reduce contaminant mass and leachability in soil.

PubMed

Cassidy, Daniel P; Srivastava, Vipul J; Dombrowski, Frank J; Lingle, James W

2015-10-30

Laboratory batch reactors were maintained for 32 weeks to test the potential for an in situ remedy that combines chemical oxidation, stabilization, and anaerobic bioremediation in a single application to treat soil from a manufactured gas plant, contaminated with polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Portland cement and slaked lime were used to activate the persulfate and to stabilize/encapsulate the contaminants that were not chemically oxidized. Native sulfate-reducing bacteria degraded residual contaminants using the sulfate left after persulfate activation. The ability of the combined remedy to reduce contaminant mass and leachability was compared with NaOH-activated persulfate, stabilization, and sulfate-reducing bioremediation as stand-alone technologies. The stabilization amendments increased pH and temperature sufficiently to activate the persulfate within 1 week. Activation with both stabilization amendments and NaOH removed between 55% and 70% of PAH and BTEX. However, combined persulfate and stabilization significantly reduced the leachability of residual BTEX and PAH compared with NaOH activation. Sulfide, 2-naphthoic acid, and the abundance of subunit A of the dissimilatory sulfite reductase gene (dsrA) were used to monitor native sulfate-reducing bacteria, which were negatively impacted by activated persulfate, but recovered completely within weeks. Copyright © 2015 Elsevier B.V. All rights reserved.

Steady-State Multiplicity Features of Chemically Reacting Systems.

ERIC Educational Resources Information Center

Luss, Dan

1986-01-01

Analyzes steady-state multiplicity in chemical reactors, focusing on the use of two mathematical tools, namely, the catastrophe theory and the singularity theory with a distinguished parameter. These tools can be used to determine the maximum number of possible solutions and the different types of bifurcation diagrams. (JN)

Racial Differences in Mathematics Test Scores for Advanced Mathematics Students

ERIC Educational Resources Information Center

Minor, Elizabeth Covay

2016-01-01

Research on achievement gaps has found that achievement gaps are larger for students who take advanced mathematics courses compared to students who do not. Focusing on the advanced mathematics student achievement gap, this study found that African American advanced mathematics students have significantly lower test scores and are less likely to be…

Primary School Pre-Service Mathematics Teachers' Views on Mathematical Modeling

ERIC Educational Resources Information Center

Karali, Diren; Durmus, Soner

2015-01-01

The current study aimed to identify the views of pre-service teachers, who attended a primary school mathematics teaching department but did not take mathematical modeling courses. The mathematical modeling activity used by the pre-service teachers was developed with regards to the modeling activities utilized by Lesh and Doerr (2003) in their…

Why do early mathematics skills predict later reading? The role of mathematical language.

PubMed

Purpura, David J; Logan, Jessica A R; Hassinger-Das, Brenna; Napoli, Amy R

2017-09-01

A growing body of evidence indicates that the development of mathematics and literacy skills is highly related. The importance of literacy skills-specifically language-for mathematics development has been well rationalized. However, despite several prominent studies indicating that mathematics skills are highly predictive of literacy development, the reason for this relation is not well understood. The purpose of this study was to identify how and why early mathematics is predictive of early literacy development. Participants included 125 preschool children 3-5 years old (M = 4 years 3 months). Participants were assessed on mathematics, literacy, and cognitive measures in both the fall and spring of their preschool year. Mediation analyses indicated that the relation between early mathematics and literacy skills is mediated by children's mathematical language skills. These findings suggest that, in prior research identifying mathematical performance as a significant predictor of later literacy skills, mathematical performance may have acted only as a proxy measure for more complex language skills such as those assessed on a mathematical language measure. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

[Applications of mathematical statistics methods on compatibility researches of traditional Chinese medicines formulae].

PubMed

Mai, Lan-Yin; Li, Yi-Xuan; Chen, Yong; Xie, Zhen; Li, Jie; Zhong, Ming-Yu

2014-05-01

The compatibility of traditional Chinese medicines (TCMs) formulae containing enormous information, is a complex component system. Applications of mathematical statistics methods on the compatibility researches of traditional Chinese medicines formulae have great significance for promoting the modernization of traditional Chinese medicines and improving clinical efficacies and optimizations of formulae. As a tool for quantitative analysis, data inference and exploring inherent rules of substances, the mathematical statistics method can be used to reveal the working mechanisms of the compatibility of traditional Chinese medicines formulae in qualitatively and quantitatively. By reviewing studies based on the applications of mathematical statistics methods, this paper were summarized from perspective of dosages optimization, efficacies and changes of chemical components as well as the rules of incompatibility and contraindication of formulae, will provide the references for further studying and revealing the working mechanisms and the connotations of traditional Chinese medicines.

Reduced modeling of signal transduction – a modular approach

PubMed Central

Koschorreck, Markus; Conzelmann, Holger; Ebert, Sybille; Ederer, Michael; Gilles, Ernst Dieter

2007-01-01

Background Combinatorial complexity is a challenging problem in detailed and mechanistic mathematical modeling of signal transduction. This subject has been discussed intensively and a lot of progress has been made within the last few years. A software tool (BioNetGen) was developed which allows an automatic rule-based set-up of mechanistic model equations. In many cases these models can be reduced by an exact domain-oriented lumping technique. However, the resulting models can still consist of a very large number of differential equations. Results We introduce a new reduction technique, which allows building modularized and highly reduced models. Compared to existing approaches further reduction of signal transduction networks is possible. The method also provides a new modularization criterion, which allows to dissect the model into smaller modules that are called layers and can be modeled independently. Hallmarks of the approach are conservation relations within each layer and connection of layers by signal flows instead of mass flows. The reduced model can be formulated directly without previous generation of detailed model equations. It can be understood and interpreted intuitively, as model variables are macroscopic quantities that are converted by rates following simple kinetics. The proposed technique is applicable without using complex mathematical tools and even without detailed knowledge of the mathematical background. However, we provide a detailed mathematical analysis to show performance and limitations of the method. For physiologically relevant parameter domains the transient as well as the stationary errors caused by the reduction are negligible. Conclusion The new layer based reduced modeling method allows building modularized and strongly reduced models of signal transduction networks. Reduced model equations can be directly formulated and are intuitively interpretable. Additionally, the method provides very good approximations especially for

The Mathematical Event: Mapping the Axiomatic and the Problematic in School Mathematics

ERIC Educational Resources Information Center

de Freitas, Elizabeth

2013-01-01

Traditional philosophy of mathematics has been concerned with the nature of mathematical objects rather than events. This traditional focus on reified objects is reflected in dominant theories of learning mathematics whereby the learner is meant to acquire familiarity with ideal mathematical objects, such as number, polygon, or tangent. I argue…

A Comparative Study of the FET Phase Mathematical Literacy and Mathematics Curriculum

ERIC Educational Resources Information Center

Mhakure, Duncan; Mokoena, Mamolahluwa Amelia

2011-01-01

This article is based on a study that compared the FET (further education and training) phase mathematics literacy curriculum and mathematics curriculum. The study looked into how the conceptualization of a mathematical literacy curriculum enhanced the acquisition of mathematical concepts among the learners. In order to carry out this comparison…

Mathematical Geology.

ERIC Educational Resources Information Center

Jones, Thomas A.

1983-01-01

Mathematical techniques used to solve geological problems are briefly discussed (including comments on use of geostatistics). Highlights of conferences/meetings and conference papers in mathematical geology are also provided. (JN)

Secondary Teachers’ Mathematics-related Beliefs and Knowledge about Mathematical Problem-solving

NASA Astrophysics Data System (ADS)

E Siswono, T. Y.; Kohar, A. W.; Hartono, S.

2017-02-01

This study investigates secondary teachers’ belief about the three mathematics-related beliefs, i.e. nature of mathematics, teaching mathematics, learning mathematics, and knowledge about mathematical problem solving. Data were gathered through a set of task-based semi-structured interviews of three selected teachers with different philosophical views of teaching mathematics, i.e. instrumental, platonist, and problem solving. Those teachers were selected from an interview using a belief-related task from purposively selected teachers in Surabaya and Sidoarjo. While the interviews about knowledge examine teachers’ problem solving content and pedagogical knowledge, the interviews about beliefs examine their views on several cases extracted from each of such mathematics-related beliefs. Analysis included the categorization and comparison on each of beliefs and knowledge as well as their interaction. Results indicate that all the teachers did not show a high consistency in responding views of their mathematics-related beliefs, while they showed weaknesses primarily on problem solving content knowledge. Findings also point out that teachers’ beliefs have a strong relationship with teachers’ knowledge about problem solving. In particular, the instrumental teacher’s beliefs were consistent with his insufficient knowledge about problem-solving, while both platonist and problem-solving teacher’s beliefs were consistent with their sufficient knowledge of either content or pedagogical problem solving.

Middle School Mathematics Students' Perspectives on the Study of Mathematics

ERIC Educational Resources Information Center

Vaughn, Christy H.

2012-01-01

This qualitative study addressed the perceptions toward the study of mathematics by middle school students who had formerly been in a remedial mathematics program. The purpose of the study was to explore the past experiences of nine students in order to determine what is needed for them to feel successful in mathematics. The conceptual framework…

Mathematics disorder

MedlinePlus

... this page: //medlineplus.gov/ency/article/001534.htm Mathematics disorder To use the sharing features on this page, please enable JavaScript. Mathematics disorder is a condition in which a child's ...

From Searle's Chinese Room to the Mathematics Classroom: Technical and Cognitive Mathematics

ERIC Educational Resources Information Center

Gavalas, Dimitris

2007-01-01

Employing Searle's views, I begin by arguing that students of Mathematics behave similarly to machines that manage symbols using a set of rules. I then consider two types of Mathematics, which I call "Cognitive Mathematics" and "Technical Mathematics" respectively. The former type relates to concepts and meanings, logic and sense, whilst the…

Explorations in Mathematics

ERIC Educational Resources Information Center

Muses, Charles

1977-01-01

Mathematics provides a language by which man can explore, and describe precisely and profoundly, any possible set of characteristics or relationships in nature. Discussed in this article are several mathematical topics including some historical perspectives in mathematics and new pioneering in hypernumbers. Supplementary sections include…

The Early Prevention of Mathematics Difficulty: Its Power and Limitations

PubMed Central

Fuchs, Lynn S.; Fuchs, Douglas; Compton, Donald L.

2012-01-01

In this article, the authors consider the power and limitations of responsiveness-to-intervention (RTI) for reducing the need for ongoing and intensive services for the segment of the school population traditionally identified as having a learning disability in mathematics. To assess the robustness of RTI, the authors describe four studies with strong demonstrations of efficacy, as they considered the percentage of students who failed to respond, the post-tutoring achievement gap between tutored and not-at-risk students, and the extent of transfer across components of the mathematics curriculum. The authors then discuss implications and additional research questions pertaining to mathematics intervention generally and within the context of RTI. They conclude with a proposal for an expanded conceptualization of RTI. PMID:22491809

The early prevention of mathematics difficulty: its power and limitations.

PubMed

Fuchs, Lynn S; Fuchs, Douglas; Compton, Donald L

2012-01-01

In this article, the authors consider the power and limitations of responsiveness-to-intervention (RTI) for reducing the need for ongoing and intensive services for the segment of the school population traditionally identified as having a learning disability in mathematics. To assess the robustness of RTI, the authors describe four studies with strong demonstrations of efficacy, as they considered the percentage of students who failed to respond, the post-tutoring achievement gap between tutored and not-at-risk students, and the extent of transfer across components of the mathematics curriculum. The authors then discuss implications and additional research questions pertaining to mathematics intervention generally and within the context of RTI. They conclude with a proposal for an expanded conceptualization of RTI.

Oncolytic potency and reduced virus tumor-specificity in oncolytic virotherapy. A mathematical modelling approach.

PubMed

Mahasa, Khaphetsi Joseph; Eladdadi, Amina; de Pillis, Lisette; Ouifki, Rachid

2017-01-01

In the present paper, we address by means of mathematical modeling the following main question: How can oncolytic virus infection of some normal cells in the vicinity of tumor cells enhance oncolytic virotherapy? We formulate a mathematical model describing the interactions between the oncolytic virus, the tumor cells, the normal cells, and the antitumoral and antiviral immune responses. The model consists of a system of delay differential equations with one (discrete) delay. We derive the model's basic reproductive number within tumor and normal cell populations and use their ratio as a metric for virus tumor-specificity. Numerical simulations are performed for different values of the basic reproduction numbers and their ratios to investigate potential trade-offs between tumor reduction and normal cells losses. A fundamental feature unravelled by the model simulations is its great sensitivity to parameters that account for most variation in the early or late stages of oncolytic virotherapy. From a clinical point of view, our findings indicate that designing an oncolytic virus that is not 100% tumor-specific can increase virus particles, which in turn, can further infect tumor cells. Moreover, our findings indicate that when infected tissues can be regenerated, oncolytic viral infection of normal cells could improve cancer treatment.

Rethinking Mathematics.

ERIC Educational Resources Information Center

Abad, Ernesto A.

1994-01-01

Poses solutions for our failure to show students how well mathematics interlocks with the physical structures of the Universe. Some examples are provided to illustrate the natural integration of mathematics and science. (ZWH)

EPA Releases Guidance on a Voluntary Pilot Program to Reduce Animal Testing

EPA Pesticide Factsheets

EPA is announcing the start of a voluntary pilot program to evaluate the usefulness and acceptability of a mathematical tool that estimates the toxicological classification of a chemical, which is used in the GHS.

Mathematics Teaching Today

ERIC Educational Resources Information Center

Martin, Tami S.; Speer, William R.

2009-01-01

This article describes features, consistent messages, and new components of "Mathematics Teaching Today: Improving Practice, Improving Student Learning" (NCTM 2007), an updated edition of "Professional Standards for Teaching Mathematics" (NCTM 1991). The new book describes aspects of high-quality mathematics teaching; offers a model for observing,…

Mathematics and the surgeon.

PubMed Central

Crank, J.

1976-01-01

The surgeon uses elementary mathematics just as much as any other educated layman. In his professional life, however, much of the knowledge and skill on which he relies has had a mathematical strand in its development, possibly woven into the supporting disciplines such as physics, chemistry, biology, and bioengineering. The valves and limitations of mathematical models are examined briefly in the general medical field and particularly in relation to the surgeon. Arithmetic and statistics are usually regarded as the most immediately useful parts of mathematics. Examples are cited, however, of medical postgraduate work which uses other highly advanced mathematical techniques. The place of mathematics in postgraduate and postexperience teaching courses is touched on. The role of a mathematical consultant in the medical team is discussed. PMID:942167

Program Helps Generate Boundary-Element Mathematical Models

NASA Technical Reports Server (NTRS)

Goldberg, R. K.

1995-01-01

Composite Model Generation-Boundary Element Method (COM-GEN-BEM) computer program significantly reduces time and effort needed to construct boundary-element mathematical models of continuous-fiber composite materials at micro-mechanical (constituent) scale. Generates boundary-element models compatible with BEST-CMS boundary-element code for anlaysis of micromechanics of composite material. Written in PATRAN Command Language (PCL).

Applying the three R's: Reduce, reuse, and recycle in the chemical industry.

PubMed

Mostafa, Mohamed K; Peters, Robert W

2017-03-01

Pollution prevention (P2) assessment was conducted by applying the three R's, reduce, reuse, and recycle, in a chemical industry for the purpose of reducing the amount of wastewater generated, reusing paint wastewater in the manufacture of cement bricks, recycling cooling water, and improving water usage efficiency. The results of this study showed that the annual wastewater flow generated from the paint manufacturing can be reduced from 1,100 m 3 to 488.4 m 3 (44.4% reduction) when a high-pressure hose is used. Two mixtures were prepared. The first mixture (A) contains cement, coarse aggregate, fine aggregate, Addicrete BVF, and clean water. The second mixture (B) contains the same components used in the first mixture, except that paint wastewater was used instead of the clean water. The prepared samples were tested for water absorption, toxicity, reactivity, compressive strength, ignitability, and corrosion. The tests results indicated that using paint wastewater in the manufacture of the cement bricks improved the mechanical properties of the bricks. The toxicity test results showed that the metals concentration in the bricks did not exceed the U.S. EPA limits. This company achieved the goal of zero liquid discharge (ZLD), especially after recycling 2,800 m 3 of cooling water. The total annual saving could reach $42,570 with a payback period of 41 days. This research focused on improving the water usage efficiency, reducing the quantity of wastewater generated, and potentially reusing wastewater in the manufacture of cement bricks. Reusing paint wastewater in the manufacture of the bricks prevents the hazardous pollutants in the wastewater (calcium carbonate, styrene acrylic resins, colored pigments, and titanium dioxide) from entering and polluting the surface water and the environment. We think that this paper will help to find the most efficient and cost-effective way to manage paint wastewater and conserve fresh water resources. We also believe that this

[On the founders of the Institute of Mathematics and Physics, University of Bahia].

PubMed

Dias, A L

The reduced number of female students of mathematics at the University of Bahia School of Philosophy (Faculdade de Filosofia, Universidade da Bahia - FF/UBa) is quite surprising. To date, they are concentrated in areas traditionally viewed as feminine whereas men predominate in the mathematical fields. I have examined interview data from a few women who graduated in mathematics and went on to teach at the University of Bahia School of Mathematics (Faculdade de Filosofia - FF) and at the Institute of Mathematics and Physics (Instituto de Matemática e Física - IMF), where they were soon to outnumber men and constitute the majority of the mathematics teaching staff. In this study, I have investigated the course of their careers over time: from their early student days, through their time as teaching assistants and professors, and finally as founders of the Institute of Mathematics and Physics, in 1960. Special reference is made to Martha Maria de Souza Dantas, organizer of the I Brazilian Conference on Mathematics Teaching, an event which has provided the groundwork for what was to become the Institute (IMF); and to Arlete Cerqueira Lima, the mastermind behind its creation.

Determination of minimum enzymatic decolorization time of reactive dye solution by spectroscopic & mathematical approach.

PubMed

Celebi, Mithat; Ozdemir, Zafer Omer; Eroglu, Emre; Altikatoglu, Melda; Guney, Ibrahim

2015-02-01

Synthetic dyes are very important for textile dyeing, paper printing, color photography and petroleum products. Traditional methods of dye removal include biodegradation, precipitation, adsorption, chemical degradation, photo degradation, and chemical coagulation. Dye decolorization with enzymatic reaction is an important issue for several research field (chemistry, environment) In this study, minimum decolorization time of Remazol Brilliant Blue R dye with Horseradish peroxidase enzyme was calculated using with mathematical equation depending on experimental data. Dye decolorization was determined by monitoring the absorbance decrease at the specific maximum wavelength for dye. All experiments were carried out with different initial dye concentrations of Remazol Brilliant Blue R at 25 degrees C constant temperature for 30 minutes. The development of the least squares estimators for a nonlinear model brings about complications not encountered in the case of the linear model. Decolorization times for completely removal of dye were calculated according to equation. It was shown that mathematical equation was conformed exponential curve for dye degradation.

Modeling of chemical inhibition from amyloid protein aggregation kinetics.

PubMed

Vázquez, José Antonio

2014-02-27

The process of amyloid proteins aggregation causes several human neuropathologies. In some cases, e.g. fibrillar deposits of insulin, the problems are generated in the processes of production and purification of protein and in the pump devices or injectable preparations for diabetics. Experimental kinetics and adequate modelling of chemical inhibition from amyloid aggregation are of practical importance in order to study the viable processing, formulation and storage as well as to predict and optimize the best conditions to reduce the effect of protein nucleation. In this manuscript, experimental data of insulin, Aβ42 amyloid protein and apomyoglobin fibrillation from recent bibliography were selected to evaluate the capability of a bivariate sigmoid equation to model them. The mathematical functions (logistic combined with Weibull equation) were used in reparameterized form and the effect of inhibitor concentrations on kinetic parameters from logistic equation were perfectly defined and explained. The surfaces of data were accurately described by proposed model and the presented analysis characterized the inhibitory influence on the protein aggregation by several chemicals. Discrimination between true and apparent inhibitors was also confirmed by the bivariate equation. EGCG for insulin (working at pH = 7.4/T = 37°C) and taiwaniaflavone for Aβ42 were the compounds studied that shown the greatest inhibition capacity. An accurate, simple and effective model to investigate the inhibition of chemicals on amyloid protein aggregation has been developed. The equation could be useful for the clear quantification of inhibitor potential of chemicals and rigorous comparison among them.

Defining Mathematical Giftedness

ERIC Educational Resources Information Center

Parish, Linda

2014-01-01

This theoretical paper outlines the process of defining "mathematical giftedness" for a present study on how primary school teaching shapes the mindsets of children who are mathematically gifted. Mathematical giftedness is not a badge of honour or some special value attributed to a child who has achieved something exceptional.…

Making Mathematics Phenomenal

ERIC Educational Resources Information Center

Pratt, Dave

2012-01-01

Mathematics is often portrayed as an "abstract" cerebral subject, beyond the reach of many. In response, research with digital technology has led to innovative design in which mathematics can be experienced much like everyday phenomena. This lecture examines how careful design can "phenomenalise" mathematics and support not only engagement but…

Conceptions and Images of Mathematics Professors on Teaching Mathematics in School.

ERIC Educational Resources Information Center

Pehkonen, Erkki

1999-01-01

Clarifies what kind of mathematical beliefs are conveyed to student teachers during their studies. Interviews mathematics professors (n=7) from five Finnish universities who were responsible for mathematics teacher education. Professors estimated that teachers' basic knowledge was poor and old-fashioned, requiring improvement, and they emphasized…

Mathematics teachers' support and retention: using Maslow's hierarchy to understand teachers' needs

NASA Astrophysics Data System (ADS)

Fisher, Molly H.; Royster, David

2016-10-01

As part of a larger study, four mathematics teachers from diverse backgrounds and teaching situations report their ideas on teacher stress, mathematics teacher retention, and their feelings about the needs of mathematics teachers, as well as other information crucial to retaining quality teachers. The responses from the participants were used to develop a hierarchy of teachers' needs that resembles Maslow's hierarchy, which can be used to better support teachers in various stages of their careers. The interviews revealed both non content-specific and content-specific needs within the hierarchy. The responses show that teachers found different schools foster different stress levels and that as teachers they used a number of resources for reducing stress. Other mathematics-specific ideas are also discussed such as the amount of content and pedagogy courses required for certification.

The Use of the History of Mathematics in the Teaching Pre-Service Mathematics Teachers

ERIC Educational Resources Information Center

Galante, Dianna

2014-01-01

Many scholars have written about using the history of mathematics in the teaching of pre-service mathematics teachers. For this study, pre-service mathematics teachers developed an electronic journal of reflections based on presentations in the history of mathematics in a secondary mathematics education course. The main purpose of the…

Construction of mathematical knowledge using graphic calculators (CAS) in the mathematics classroom

NASA Astrophysics Data System (ADS)

Hitt, Fernando

2011-09-01

Mathematics education researchers are asking themselves about why technology has impacted heavily on the social environment and not in the mathematics classroom. The use of technology in the mathematics classroom has not had the expected impact, as it has been its use in everyday life (i.e. cell phone). What about teachers' opinions? Mathematics teachers can be divided into three categories: those with a boundless overflow (enthusiasm) who want to use the technology without worrying much about the construction of mathematical concepts, those who reject outright the use of technology because they think that their use inhibits the development of mathematical skills and others that reflect on the balance that must exist between paper-pencil activities and use of technology. The mathematics teacher, by not having clear examples that support this last option about the balance of paper-pencil activities and technology, opt for one of the extreme positions outlined above. In this article, we show the results of research on a methodology based on collaborative learning (ACODESA) in the training of mathematics teachers in secondary schools and implementation of activities in an environment of paper-pencil and CAS in the mathematics classroom. We also note that with the development of technology on the use of electronic tablets and interactive whiteboards, these activities will take on greater momentum in the near future.

Mathematical Perspectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glimm, J.

2009-10-14

Progress for the past decade or so has been extraordinary. The solution of Fermat's Last Theorem [11] and of the Poincare Conjecture [1] have resolved two of the most outstanding challenges to mathematics. For both cases, deep and advanced theories and whole subfields of mathematics came into play and were developed further as part of the solutions. And still the future is wide open. Six of the original seven problems from the Clay Foundation challenge remain open, the 23 DARPA challenge problems are open. Entire new branches of mathematics have been developed, including financial mathematics and the connection between geometrymore » and string theory, proposed to solve the problems of quantized gravity. New solutions of the Einstein equations, inspired by shock wave theory, suggest a cosmology model which fits accelerating expansion of the universe possibly eliminating assumptions of 'dark matter'. Intellectual challenges and opportunities for mathematics are greater than ever. The role of mathematics in society continues to grow; with this growth comes new opportunities and some growing pains; each will be analyzed here. We see a broadening of the intellectual and professional opportunities and responsibilities for mathematicians. These trends are also occuring across all of science. The response can be at the level of the professional societies, which can work to deepen their interactions, not only within the mathematical sciences, but also with other scientific societies. At a deeper level, the choices to be made will come from individual mathematicians. Here, of course, the individual choices will be varied, and we argue for respect and support for this diversity of responses. In such a manner, we hope to preserve the best of the present while welcoming the best of the new.« less

Linear systems on balancing chemical reaction problem

NASA Astrophysics Data System (ADS)

Kafi, R. A.; Abdillah, B.

2018-01-01

The concept of linear systems appears in a variety of applications. This paper presents a small sample of the wide variety of real-world problems regarding our study of linear systems. We show that the problem in balancing chemical reaction can be described by homogeneous linear systems. The solution of the systems is obtained by performing elementary row operations. The obtained solution represents the finding coefficients of chemical reaction. In addition, we present a computational calculation to show that mathematical software such as Matlab can be used to simplify completion of the systems, instead of manually using row operations.

Algorithm For Hypersonic Flow In Chemical Equilibrium

NASA Technical Reports Server (NTRS)

Palmer, Grant

1989-01-01

Implicit, finite-difference, shock-capturing algorithm calculates inviscid, hypersonic flows in chemical equilibrium. Implicit formulation chosen because overcomes limitation on mathematical stability encountered in explicit formulations. For dynamical portion of problem, Euler equations written in conservation-law form in Cartesian coordinate system for two-dimensional or axisymmetric flow. For chemical portion of problem, equilibrium state of gas at each point in computational grid determined by minimizing local Gibbs free energy, subject to local conservation of molecules, atoms, ions, and total enthalpy. Major advantage: resulting algorithm naturally stable and captures strong shocks without help of artificial-dissipation terms to damp out spurious numerical oscillations.

Empowering Mathematical Practices

ERIC Educational Resources Information Center

Coomes, Jacqueline; Lee, Hyung Sook

2017-01-01

Mathematics teachers want to empower students as mathematical thinkers and doers (NCTM 2000). Specific ways of thinking and doing mathematics were described in the Process Standards (NCTM 2000); they were further characterized as habits of mind (Mark, Goldenberg, and Sword 2010); and more recently, they were detailed in the Common Core's Standards…

Topics in Mathematics.

ERIC Educational Resources Information Center

Posey, Johnsie Jo, Ed.; And Others

This manual is a collection of materials and teaching strategies to motivate the development of mathematical ideas in secondary school mathematics programs or in beginning college mathematics programs. The unit is written for the instructor with step-by-step procedures including lists of needed materials. The exercises in this unit also appear in…

Mathematics and Sports

ERIC Educational Resources Information Center

Gallian, Joseph A., Ed.

2010-01-01

"Mathematics and Sports", edited by Joseph A. Gallian, gathers 25 articles that illuminate the power and role of mathematics in the worlds of professional and recreational play. Divided into sections by the kind of sports, the book offers source materials for classroom use and student projects. Readers will encounter mathematical ideas from an…

Primary Mathematics Trainee Teacher Confidence and Its Relationship to Mathematical Knowledge

ERIC Educational Resources Information Center

Norton, Stephen J.

2017-01-01

The purpose of this paper is to examine trainee primary school teachers' confidence in their mathematical content knowledge (MCK) and confidence to teach specific primary mathematics concepts (mathematics pedagogical content knowledge --MPCK) which was correlated to their actual MCK on specific tasks. For this correlational study survey and test…

Math Worlds: Philosophical and Social Studies of Mathematics and Mathematics Education.

ERIC Educational Resources Information Center

Restivo, Sal, Ed.; And Others

This book is a compilation of papers from authors who are all concerned with what bearing mathematical practice has on the production or construction of mathematics. The sections and chapters are: (1) General Introduction: "The Promethean Task of Bringing Mathematics to Earth" (S. Restivo); (2) Philosophical Perspectives: "Foundations of…

Studies in Mathematics, Volume X. Applied Mathematics in the High School.

ERIC Educational Resources Information Center

Schiffer, Max M.

This publication contains a sequence of lectures given to high school mathematics teachers by the author. Applications of mathematics emphasized are elementary algebra, geometry, and matrix algebra. Included are: (1) an introduction concerning teaching applications of mathematics; (2) Chapter 1: Mechanics for the High School Student; (3) Chapter…

Mathematics, anxiety, and the brain.

PubMed

Moustafa, Ahmed A; Tindle, Richard; Ansari, Zaheda; Doyle, Margery J; Hewedi, Doaa H; Eissa, Abeer

2017-05-24

Given that achievement in learning mathematics at school correlates with work and social achievements, it is important to understand the cognitive processes underlying abilities to learn mathematics efficiently as well as reasons underlying the occurrence of mathematics anxiety (i.e. feelings of tension and fear upon facing mathematical problems or numbers) among certain individuals. Over the last two decades, many studies have shown that learning mathematical and numerical concepts relies on many cognitive processes, including working memory, spatial skills, and linguistic abilities. In this review, we discuss the relationship between mathematical learning and cognitive processes as well as the neural substrates underlying successful mathematical learning and problem solving. More importantly, we also discuss the relationship between these cognitive processes, mathematics anxiety, and mathematics learning disabilities (dyscalculia). Our review shows that mathematical cognition relies on a complex brain network, and dysfunction to different segments of this network leads to varying manifestations of mathematical learning disabilities.

Civic Mathematics: A Real-Life General Mathematics Course.

ERIC Educational Resources Information Center

Vatter, Terry

1994-01-01

Presents a civic mathematics curriculum that encompasses issues of race and gender, poverty and wealth, the environment, and concerns of teenagers. Includes lists of mathematics skills and aspects of the issues and a sample lesson on water resources. Quarterly projects are suggested as an alternative to exams. (MKR)

It's all just mathematics

NASA Astrophysics Data System (ADS)

Tegmark, Max

2014-02-01

The world can be described using mathematical equations and numbers, but why does maths do it so well? In his new book Our Mathematical Universe, a section of which is abridged and edited here, Max Tegmark makes the radical proposal that our reality isn't just described by mathematics - it is mathematics.

The Only Absolute Truth in Mathematics is the Myth of Mathematics as Universal

ERIC Educational Resources Information Center

Kantner, M. Joanne

2008-01-01

Culture and national origin can affect thinking about mathematics and mathematics learning. The myth that mathematics is objective and culture free becomes a barrier to adults learning mathematics. Adult educators must reflect upon culture's influence on learning and recognize the implications of universality myths on students' learning in…

Mathematics and Water in the Garden: Weaving Mathematics into the Students' Lived Environment

ERIC Educational Resources Information Center

Clarkson, Philip

2010-01-01

In an earlier issue of "Australian Primary Mathematics Classroom," Sparrow discussed the concept of real-world mathematics and the use of mathematics to explore problems in real-life situations. Environmental issues have provided a context that some teachers have used for teaching mathematics. An example of a particular environmental…

Preservice Elementary Mathematics Teachers' Level of Relating Mathematical Concepts in Daily Life Contexts

ERIC Educational Resources Information Center

Akkus, Oylum

2008-01-01

The purpose of this study was to investigate preservice elementary mathematics teachers' ability of relating mathematical concepts and daily life context. Two research questions were set; what is the preservice elementary mathematics teachers' level of relating mathematical concepts and daily life context regarding to their education year and…

Mathematics and mysticism.

PubMed

Abraham, Ralph

2015-12-01

Is there a world of mathematics above and beyond ordinary reality, as Plato proposed? Or is mathematics a cultural construct? In this short article we speculate on the place of mathematical reality from the perspective of the mystical cosmologies of the ancient traditions of meditation, psychedelics, and divination. Copyright © 2015. Published by Elsevier Ltd.

Mathematics for Electronics.

ERIC Educational Resources Information Center

Clary, Joseph R.; Nery, Karen P.

This set of 20 modules was designed for use primarily to help teach and reinforce the basic mathematics skills in electronics classes. The modules are based on electronics competencies that require mathematics skills, as determined by a panel of high school electronics and mathematics teachers. Each module consists of one or two pages of basic…

Latinos and Mathematics.

ERIC Educational Resources Information Center

Ortiz-Franco, Luis

An historical perspective reveals that sophisticated mathematical activity has been going on in the Latino culture for thousands of years. This paper provides a general definition of the area of mathematics education that deals with issues of culture and mathematics (ethnomathematics) and defines what is meant by the term Latino in this essay.…

The Effects of Pedagogical Agents on Mathematics Anxiety and Mathematics Learning

ERIC Educational Resources Information Center

Wei, Quan

2010-01-01

The purpose of this study was to investigate the impact of the mathematics anxiety treatment messages in a computer-based environment on ninth-grade students' mathematics anxiety and mathematics learning. The study also examined whether the impact of the treatment messages would be differentiated by learner's gender and by learner's prior…

Secondary Mathematics Coaching: The Components of Effective Mathematics Coaching and Implications

ERIC Educational Resources Information Center

Bengo, Priscilla

2016-01-01

Mathematics coaching, which can be defined broadly as job-embedded learning for mathematics teachers with someone who can help, is being used in Canada to improve teaching practice and increase student achievement. Mathematics coaching research is quite new with little written on the components of effective coaching. The paper attempts to…

Studies in Mathematics Education. Volume 6. Out-of-School Mathematics Education.

ERIC Educational Resources Information Center

Morris, Robert, Ed.

This is the sixth volume in a series designed to improve mathematics instruction by providing resource materials for those responsible for mathematics teaching. Focusing on out-of-school mathematics education, this volume presents a panorama of current practices around the world and suggests future trends. Subjects considered include: (1)…

Applications: Students, the Mathematics Curriculum and Mathematics Textbooks

ERIC Educational Resources Information Center

Kilic, Cigdem

2013-01-01

Problem posing is one of the most important topics in a mathematics education. Through problem posing, students gain mathematical abilities and concepts and teachers can evaluate their students and arrange adequate learning environments. The aim of the present study is to investigate Turkish primary school teachers' opinions about problem posing…

Mathematical Difficulty: Does Early Intervention Enhance Mathematical Performance?

ERIC Educational Resources Information Center

Graham, Jennifer

2008-01-01

The need to ask educators about their opinions on the subject to what extent early intervention methods enhance mathematical performance is long overdue. The purpose of this quantitative research is to examine the extent to which teachers agree that early intervention methods enhance the mathematical performance of students with mathematical…

Making Sense of Mathematics

ERIC Educational Resources Information Center

Umphrey, Jan

2011-01-01

The National Council of Teachers of Mathematics (NCTM) is a voice and advocate for mathematics educators, working to ensure that all students receive equitable mathematics learning of the highest quality. To help teachers and school leaders understand the Common Core State Standards for Mathematics (CCSSM) and to point out how the CCSSM can be…

Conceptual metaphors and mathematical practice: on cognitive studies of historical developments in mathematics.

PubMed

Schlimm, Dirk

2013-04-01

This article looks at recent work in cognitive science on mathematical cognition from the perspective of history and philosophy of mathematical practice. The discussion is focused on the work of Lakoff and Núñez, because this is the first comprehensive account of mathematical cognition that also addresses advanced mathematics and its history. Building on a distinction between mathematics as it is presented in textbooks and as it presents itself to the researcher, it is argued that the focus of cognitive analyses of historical developments of mathematics has been primarily on the former, even if they claim to be about the latter. Copyright © 2013 Cognitive Science Society, Inc.

The Role of Mathematical Fiction in the Learning of Mathematics in Primary School

ERIC Educational Resources Information Center

Padula, Janice

2004-01-01

This article classifies and describes a selection of mathematical fiction. It also provides some practical activities teachers or parents can use to help make the mathematics more explicit and engaging for their children. Not many people, apart from primary teachers, are aware of mathematical fiction or mathematical picture storybooks, although…

Detecting Strengths and Weaknesses in Learning Mathematics through a Model Classifying Mathematical Skills

ERIC Educational Resources Information Center

Karagiannakis, Giannis N.; Baccaglini-Frank, Anna E.; Roussos, Petros

2016-01-01

Through a review of the literature on mathematical learning disabilities (MLD) and low achievement in mathematics (LA) we have proposed a model classifying mathematical skills involved in learning mathematics into four domains (Core number, Memory, Reasoning, and Visual-spatial). In this paper we present a new experimental computer-based battery…

Investigating Pre-Service Teachers' Mathematics Anxiety Using the Revised Mathematics Anxiety Scale (RMARS)

ERIC Educational Resources Information Center

Wilson, Sue

2012-01-01

Pre-service primary (elementary) teachers' mathematics anxiety affects their engagement with and future teaching of mathematics. The study measured the range of mathematics anxiety in 219 pre-service teachers starting a teacher education course in an Australian university. They responded to the Revised Mathematics Anxiety Scale (RMARS) and a set…

Teachers' Beliefs about School Mathematics and Mathematicians' Mathematics and Their Relationship to Practice

ERIC Educational Resources Information Center

Beswick, Kim

2012-01-01

There is broad acceptance that mathematics teachers' beliefs about the nature of mathematics influence the ways in which they teach the subject. It is also recognised that mathematics as practised in typical school classrooms is different from the mathematical activity of mathematicians. This paper presents case studies of two secondary…

South Carolina Guide for Mathematics for the Technologies (Applied Vocational Mathematics).

ERIC Educational Resources Information Center

Moore, Charles; And Others

In this instructional guide, a third-level, two-semester mathematics course specifically for the student who plans a career in a vocational field is presented. The course is designed to meet the needs of students with varying mathematical backgrounds and to teach the mathematical skills required by various technical areas. In this practical…

Teaching Mathematics: Challenging the Sacred Cow of Mathematical Certainty.

ERIC Educational Resources Information Center

Borba, Marcelo C.

1992-01-01

Challenges the concept of mathematical certainty and questions whether it is a useful concept for elementary and secondary mathematics curriculum. Encourages teachers to bring this issue into the classroom and ask students to think about it critically. (HB)

The Impact of Prior Mathematics Achievement on the Relationship between High School Mathematics Curricula and Postsecondary Mathematics Performance, Course-Taking, and Persistence

ERIC Educational Resources Information Center

Post, Thomas R.; Medhanie, Amanuel; Harwell, Michael; Norman, Ke Wu; Dupuis, Danielle N.; Muchlinski, Thomas; Andersen, Edwin; Monson, Debra

2010-01-01

This retrospective study examined the impact of prior mathematics achievement on the relationship between high school mathematics curricula and student postsecondary mathematics performance. The sample (N = 4,144 from 266 high schools) was partitioned into 3 strata by ACT mathematics scores. Students completing 3 or more years of a commercially…

Secondary School Mathematics Teachers' Knowledge Levels and Use of History of Mathematics

ERIC Educational Resources Information Center

Bütüner, Suphi Önder

2018-01-01

This study describes secondary school mathematics teachers' use of history of mathematics in their classes and their knowledge levels in this field. The study population included a total of 58 secondary school mathematics teachers working at the secondary schools located in Yozgat city center, and the sample included 32 mathematics teachers from…

What Is Measured in Mathematics Tests? Construct Validity of Curriculum-Based Mathematics Measures.

ERIC Educational Resources Information Center

Thurber, Robin Schul; Shinn, Mark R.; Smolkowski, Keith

2002-01-01

Mathematics curriculum-based measurement (M-CBM) is one tool that has been developed for formative evaluation in mathematics. This study examines what constructs M-CBM actually measures in the context of a range of other mathematics measures. Results indicated that a two-factor model of mathematics where Computation and Applications were distinct…

Technical Mathematics.

ERIC Educational Resources Information Center

Flannery, Carol A.

This manuscript provides information and problems for teaching mathematics to vocational education students. Problems reflect applications of mathematical concepts to specific technical areas. The materials are organized into six chapters. Chapter 1 covers basic arithmetic, including fractions, decimals, ratio and proportions, percentages, and…

Mathematical knowledge for teaching: Making the tacit more explicit in mathematics teacher education

NASA Astrophysics Data System (ADS)

Abdullah, Mohd Faizal Nizam Lee; Vimalanandan, Lena

2017-05-01

Teaching practice during school based experiences, afford an opportunity for pre service teachers to put into practice their knowledge for teaching mathematics. Like all knowledge, Mathematical Knowledge for Teaching (MKT) is held in both tacit and explicit form, making it especially difficult to study and map during instruction. This study investigates the tacit and explicit nature of MKT held by pre service teachers in a Malaysian Teacher Education Program and how it impacts the Mathematical Quality of their instruction (MQI). This study of three mathematics pre-service teachers (PSTs), utilised videos of mathematics lessons, reflective debriefs and interviews. The findings suggest that factors such as reflecting, peer-sharing, conferencing with mentors and observing support in making tacit knowledge more explicit during planning and instruction. Implications for preparation of mathematics teachers capable of high Mathematical Quality of Instruction are also discussed.

Physical, Chemical, Bibological, and Biotechnological sciences are incomplete without each other

USDA-ARS?s Scientific Manuscript database

By coupling of mechanics, optics, and mathematics, Theodor Svedberg invented the ultracentrifuge, which allowed separation of important biological materials by high centrifugal force, resulting in physical chemical separation and characterization of atherogenic low density lipoproteins and other bio...

Perception determinants in learning mathematics

NASA Astrophysics Data System (ADS)

Mokhtar, Siti Fairus; Ali, Noor Rasidah; Rashid, Nurazlina Abdul

2015-05-01

This article described a statistical study of students' perception in mathematics. The objective of this study is to identify factors related to perception about learning mathematics among non mathematics' student. This study also determined the relationship between of these factors among non mathematics' student. 43 items questionnaires were distributed to one hundred students in UiTM Kedah who enrolled in the Business Mathematics course. These items were measured by using a semantic scale with the following anchors: 1 = strongly disagree to 7 = strongly agree. A factor analysis of respondents were identified into five factors that influencing the students' perception in mathematics. In my study, factors identified were attitude, interest, role of the teacher, role of peers and usefulness of mathematics that may relate to the perception about learning mathematics among non mathematics' student.

New Materialist Ontologies in Mathematics Education: The Body in/of Mathematics

ERIC Educational Resources Information Center

de Freitas, Elizabeth; Sinclair, Nathalie

2013-01-01

In this paper we study the mathematical body as an assemblage of human and non-human mathematical concepts. We argue that learners' bodies are always in the process of becoming assemblages of diverse and dynamic materialities. Following the work of the historian of science Karen Barad, we argue that mathematical concepts must be considered dynamic…

Attitudes of Mathematics Teachers toward Using Smart Board in Teaching Mathematics

ERIC Educational Resources Information Center

Muhanna, Wafa; Nejem, Khamis Mousa

2013-01-01

This study aimed at investigating the attitudes of mathematics teachers toward using a smart board in teaching mathematics and also to determine the effect of gender, experience, and qualification of teachers on their attitudes. The sample of this study consisted of 74 mathematics teachers--35 males and 39 females--from private schools in Amman…

Reducing drinking water supply chemical contamination: risks from underground storage tanks.

PubMed

Enander, Richard T; Hanumara, R Choudary; Kobayashi, Hisanori; Gagnon, Ronald N; Park, Eugene; Vallot, Christopher; Genovesi, Richard

2012-12-01

Drinking water supplies are at risk of contamination from a variety of physical, chemical, and biological sources. Ranked among these threats are hazardous material releases from leaking or improperly managed underground storage tanks located at municipal, commercial, and industrial facilities. To reduce human health and environmental risks associated with the subsurface storage of hazardous materials, government agencies have taken a variety of legislative and regulatory actions--which date back more than 25 years and include the establishment of rigorous equipment/technology/operational requirements and facility-by-facility inspection and enforcement programs. Given a history of more than 470,000 underground storage tank releases nationwide, the U.S. Environmental Protection Agency continues to report that 7,300 new leaks were found in federal fiscal year 2008, while nearly 103,000 old leaks remain to be cleaned up. In this article, we report on an alternate evidence-based intervention approach for reducing potential releases from the storage of petroleum products (gasoline, diesel, kerosene, heating/fuel oil, and waste oil) in underground tanks at commercial facilities located in Rhode Island. The objective of this study was to evaluate whether a new regulatory model can be used as a cost-effective alternative to traditional facility-by-facility inspection and enforcement programs for underground storage tanks. We conclude that the alternative model, using an emphasis on technical assistance tools, can produce measurable improvements in compliance performance, is a cost-effective adjunct to traditional facility-by-facility inspection and enforcement programs, and has the potential to allow regulatory agencies to decrease their frequency of inspections among low risk facilities without sacrificing compliance performance or increasing public health risks. © 2012 Society for Risk Analysis.

The Characteristics of Mathematical Creativity

ERIC Educational Resources Information Center

Sriraman, Bharath

2004-01-01

Mathematical creativity ensures the growth of mathematics as a whole. However, the source of this growth, the creativity of the mathematician, is a relatively unexplored area in mathematics and mathematics education. In order to investigate how mathematicians create mathematics, a qualitative study involving five creative mathematicians was…

A Synthesis of Mathematical and Cognitive Performances of Students with Mathematics Learning Disabilities

ERIC Educational Resources Information Center

Shin, Mikyung; Bryant, Diane Pedrotty

2015-01-01

The purpose of this study was to synthesize the findings from 23 articles that compared the mathematical and cognitive performances of students with mathematics learning disabilities (LD) to (a) students with LD in mathematics and reading, (b) age- or grade-matched students with no LD, and (c) mathematical-ability-matched younger students with no…

The effect of the Alabama Mathematics, Science, and Technology Initiative (AMSTI) on middle school students' scores in mathematics and science

NASA Astrophysics Data System (ADS)

Ramey, Toni Boyd

The purpose of this study was to determine whether the application of the Alabama Mathematics, Science, and Technology Initiative (AMSTI) program in middle schools reduced the gaps found between students' CRT scores; specifically, did the gaps found in the CRT scores within the respective subgroups race, gender, SES, and special/regular education narrow? The subject areas considered by this study were mathematics and science. Student-level data were collected and examined for longitudinal changes over a three year period in which the AMSTI program was implemented at two participating public middle schools. The dependent variables used were mathematics and science CRT scores of 6th through 8th grade students. Three repeated measures MANCOVAs and one MANOVA were conducted in order to examine possible longitudinal changes in the mathematics and science scores of the student population as well as for changes in the gaps between the demographic groups of students within the subgroups. Significant decreases were found in the differences between the respective subgroups in the variables of SES and special education. The reductions were attributed to both mathematics and science. A significant reduction in the gap found between races was found, but could not be attributed to either mathematics or science. Gender was the only subgroup in which no significant change was found. Additionally, a questionnaire was administered to teachers in four public middle schools in which AMSTI had been implemented. ANOVAs were used to examine the responses to determine how teacher training in AMSTI materials and techniques affected reported teacher attitude and frequency of usage of inquiry-based lessons. When the responses of teachers with less than one year of AMSTI training were compared to those teachers with more than one year of training, no significant change in teachers' reported attitudes toward inquiry lessons or the frequency of usage of inquiry lessons was found.

Mathematical Modeling of Cellular Metabolism.

PubMed

Berndt, Nikolaus; Holzhütter, Hermann-Georg

Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research.

Exploring the Relationship between Questioning, Enacted Mathematical Tasks, and Mathematical Discourse in Elementary School Mathematics

ERIC Educational Resources Information Center

Martin, Christie; Polly, Drew; McGee, Jen; Wang, Chuang; Lambert, Richard; Pugalee, David

2015-01-01

This study examined the mathematical discourse of elementary school teachers and their students while participating in a year-long professional development project focused on implementing reform-based mathematics curriculum. The teacher participants included 12 teachers, two from each grade level from Kindergarten through Grade 5. Field notes were…

Mathematics Fitness.

ERIC Educational Resources Information Center

Trezise, Kathleen A.

1998-01-01

Students receiving mathematics instruction relevant to life will understand that mathematics is part of the real world and not just another school subject. Presents an activity that integrates rational numbers with health-related science content as students collect data and engage in decision making. (ASK)

Mathematical modelling of intra-aortic balloon pump.

PubMed

Abdolrazaghi, Mona; Navidbakhsh, Mahdi; Hassani, Kamran

2010-10-01

Ischemic heart diseases now afflict thousands of Iranians and are the major cause of death in many industrialised countries. Mathematical modelling of an intra-aortic balloon pump (IABP) could provide a better understanding of its performance and help to represent blood flow and pressure in systemic arteries before and after inserting the pump. A mathematical modelling of the whole cardiovascular system was formulated using MATLAB software. The block diagram of the model consists of 43 compartments. All the anatomical data was extracted from the physiological references. In the next stage, myocardial infarction (MI) was induced in the model by decreasing the contractility of the left ventricle. The IABP was mathematically modelled and inserted in the model in the thoracic aorta I artery just before the descending aorta. The effects of IABP on MI were studied using the mathematical model. The normal operation of the cardiovascular system was studied firstly. The pressure-time graphs of the ventricles, atriums, aorta, pulmonary system, capillaries and arterioles were obtained. The volume-time curve of the left ventricle was also presented. The pressure-time curves of the left ventricle and thoracic aorta I were obtained for normal, MI, and inserted IABP conditions. Model verification was performed by comparing the simulation results with the clinical observations reported in the literature. IABP can be described by a theoretical model. Our model representing the cardiovascular system is capable of showing the effects of different pathologies such as MI and we have shown that MI effects can be reduced using IABP in accordance with the modelling results. The mathematical model should serve as a useful tool to simulate and better understand cardiovascular operation in normal and pathological conditions.

Maternal exposure to perfluorinated chemicals and reduced fecundity: the MIREC study.

PubMed

Vélez, M P; Arbuckle, T E; Fraser, W D

2015-03-01

What is the effect of maternal exposure to perfluorooctane sulfonate (PFOS), perflurooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) on female fecundity? Increasing concentrations of PFOA or PFHxS in maternal plasma were associated with reduced fecundability and infertility. Perfluorinated chemicals (PFCs) are a group of synthetic compounds used in industrial production. There is a concern about the effect of PFCs on fecundity, as measured by time-to-pregnancy (TTP). Although some recent studies suggest that increasing concentrations of PFCs may decrease fecundity, divergence in the methodological approaches used to evaluate this association have prevented firm conclusions being reached. The Maternal-Infant Research on Environmental Chemicals (MIREC) Study is a cohort study of 2,001 women recruited before 14 weeks of gestation in 10 cities across Canada between 2008 and 2011. A questionnaire was administered and medical chart data and biospecimens were collected from participants. After excluding women who withdrew, those for whom data were incomplete, those whose pregnancies followed birth control failure, and accounting for male fertility, 1743 participants remained. TTP was defined as the number of months of unprotected intercourse needed to become pregnant in the current pregnancy, as self-reported in the first trimester of pregnancy. Plasma concentrations of PFOA, PFOS and PFHxS measured in the first trimester were considered as a surrogate of preconception exposure. Fecundability odds ratios (FORs) were estimated using Cox proportional hazard models for discrete time. FOR < 1 denote a longer TTP and FORs >1 denote a shorter TTP. The odds of infertility (TTP > 12 months or infertility treatment in the index pregnancy) were estimated using logistic regression. Each chemical concentration (ng/ml) was log-transformed and divided by its SD. The cumulative probabilities of pregnancy at 1, 6 and 12 months were 0.42 (95% confidence interval (CI) 0

Does Time Matter in Improving Mathematical Discussions? The Influence of Mathematical Autonomy

ERIC Educational Resources Information Center

Kosko, Karl W.; Wilkins, Jesse L. M.

2015-01-01

Facilitating students' transition from less to more mathematically productive engagement in discussions is an important area of investigation. Research on mathematical whole-class discussions has consistently identified facilitating students' mathematical autonomy as a central component of this transition. Additionally, research commonly infers…

Astronomy and Mathematics Education

NASA Astrophysics Data System (ADS)

Ros, Rosa M.

There are many European countries where Astronomy does not appear as a specific course on the secondary school. In these cases Astronomy content can be introduced by means of other subjects. There are some astronomical topics within the subject of Physics but this talk concerns introducing Astronomy in Mathematics classes. Teaching Astronomy through Mathematics would result in more exposure than through Physics as Mathematics is more prevalent in the curriculum. Generally it is not easy to motivate students in Mathematics but they are motivated to find out more about the universe and Astronomy current events than appears in the media. This situation can be an excellent introduction to several mathematics topics. The teachers in secondary and high school can use this idea in order to present more attractive mathematics courses. In particular some different examples will be offered regarding * Angles and spherical coordinates considering star traces * Logarithms and visual magnitudes * Plane trigonometry related orbital movements * Spherical trigonometry in connection with ecliptic obliquity * Conic curves related to sundial at several latitudes Some students do not enjoy studying Mathematics but they can be attracted by practical situations using Applied Mathematics: Astronomy is always very attractive to teenagers.

Neural signatures of co-occurring reading and mathematical difficulties.

PubMed

Skeide, Michael A; Evans, Tanya M; Mei, Edward Z; Abrams, Daniel A; Menon, Vinod

2018-06-19

Impaired abilities in multiple domains is common in children with learning difficulties. Co-occurrence of low reading and mathematical abilities (LRLM) appears in almost every second child with learning difficulties. However, little is known regarding the neural bases of this combination. Leveraging a unique and tightly controlled sample including children with LRLM, isolated low reading ability (LR), and isolated low mathematical ability (LM), we uncover a distinct neural signature in children with co-occurring low reading and mathematical abilities differentiable from LR and LM. Specifically, we show that LRLM is neuroanatomically distinct from both LR and LM based on reduced cortical folding of the right parahippocampal gyrus, a medial temporal lobe region implicated in visual associative learning. LRLM children were further distinguished from LR and LM by patterns of intrinsic functional connectivity between parahippocampal gyrus and brain circuitry underlying reading and numerical quantity processing. Our results critically inform cognitive and neural models of LRLM by implicating aberrations in both domain-specific and domain-general brain regions involved in reading and mathematics. More generally, our results provide the first evidence for distinct multimodal neural signatures associated with LRLM, and suggest that this population displays an independent phenotype of learning difficulty that cannot be explained simply as a combination of isolated low reading and mathematical abilities. © 2018 John Wiley & Sons Ltd.

Dissociations in mathematical knowledge: case studies in Down's syndrome and Williams syndrome.

PubMed

Robinson, Sally J; Temple, Christine M

2013-02-01

A study is reported of mathematical vocabulary and factual mathematical knowledge in PQ, a 22 year old with Down's syndrome (DS) who has a verbal mental age (MA) of 9 years 2 months and ST, a 15 year old with Williams syndrome (WS) who has a verbal MA of 9 years 6 months, matched to typically developing controls. The number of mathematical words contained within PQ's lexical stores was significantly reduced as reflected by performance on lexical decision. PQ was also impaired at both naming from descriptions and describing mathematical words. These results contrast with normal lexical decision and item descriptions for concrete words reported recently for PQ (Robinson and Temple, 2010). PQ's recall of mathematical facts was also impaired, whilst his recall of general knowledge facts was normal. This performance in DS indicates a deficit in both lexical representation and semantic knowledge for mathematical words and mathematical facts. In contrast, ST, the teenager with WS had good accuracy on lexical decision, naming and generating definitions for mathematical words. This contrasted with the atypical performance with concrete words recently reported for ST (Robinson and Temple, 2009). Knowledge of addition facts and general knowledge facts was also unimpaired for ST, though knowledge of multiplication facts was weak. Together the cases form a double dissociation and provide support for the distinct representation of mathematical and concrete items within the lexical-semantic system during development. The dissociations between mathematical and general factual knowledge also indicate that different types of factual knowledge may be selectively impaired during development. There is further support for a modular structure within which mathematical vocabulary and mathematical knowledge have distinct representations. This supports the case for the independent representation of factual and language-based knowledge within the semantic system during development. Copyright

Relationships of Mathematics Anxiety, Mathematics Self-Efficacy and Mathematics Performance of Adult Basic Education Students

ERIC Educational Resources Information Center

Watts, Beverly Kinsey

2011-01-01

Competent mathematical skills are needed in the workplace as well as in the college setting. Adults in Adult Basic Education classes and programs generally perform below high school level competency, but very few studies have been performed investigating the predictors of mathematical success for adults. The current study contributes to the…

Effect of Directed Study of Mathematics Vocabulary on Standardized Mathematics Assessment Questions

ERIC Educational Resources Information Center

Waite, Adel Marlane

2017-01-01

The problems under investigation included (a) Did a directed study of mathematics vocabulary significantly affect student performance levels on standardized mathematical questions? and (b) Did the strategies used in this study significantly affect student performance levels on standardized mathematical questions? The population consisted of…

Brain Correlates of Mathematical Competence in Processing Mathematical Representations

PubMed Central

Grabner, Roland H.; Reishofer, Gernot; Koschutnig, Karl; Ebner, Franz

2011-01-01

The ability to extract numerical information from different representation formats (e.g., equations, tables, or diagrams) is a key component of mathematical competence but little is known about its neural correlate. Previous studies comparing mathematically less and more competent adults have focused on mental arithmetic and reported differences in left angular gyrus (AG) activity which were interpreted to reflect differential reliance on arithmetic fact retrieval during problem solving. The aim of the present functional magnetic resonance imaging study was to investigate the brain correlates of mathematical competence in a task requiring the processing of typical mathematical representations. Twenty-eight adults of lower and higher mathematical competence worked on a representation matching task in which they had to evaluate whether the numerical information of a symbolic equation matches that of a bar chart. Two task conditions without and one condition with arithmetic demands were administered. Both competence groups performed equally well in the non-arithmetic conditions and only differed in accuracy in the condition requiring calculation. Activation contrasts between the groups revealed consistently stronger left AG activation in the more competent individuals across all three task conditions. The finding of competence-related activation differences independently of arithmetic demands suggests that more and less competent individuals differ in a cognitive process other than arithmetic fact retrieval. Specifically, it is argued that the stronger left AG activity in the more competent adults may reflect their higher proficiency in processing mathematical symbols. Moreover, the study demonstrates competence-related parietal activation differences that were not accompanied by differential experimental performance. PMID:22069387

Mathematization in introductory physics

NASA Astrophysics Data System (ADS)

Brahmia, Suzanne M.

Mathematization is central to STEM disciplines as a cornerstone of the quantitative reasoning that characterizes these fields. Introductory physics is required for most STEM majors in part so that students develop expert-like mathematization. This dissertation describes coordinated research and curriculum development for strengthening mathematization in introductory physics; it blends scholarship in physics and mathematics education in the form of three papers. The first paper explores mathematization in the context of physics, and makes an original contribution to the measurement of physics students' struggle to mathematize. Instructors naturally assume students have a conceptual mastery of algebra before embarking on a college physics course because these students are enrolled in math courses beyond algebra. This paper provides evidence that refutes the validity of this assumption and categorizes some of the barriers students commonly encounter with quantification and representing ideas symbolically. The second paper develops a model of instruction that can help students progress from their starting points to their instructor's desired endpoints. Instructors recognize that the introductory physics course introduces new ideas at an astonishing rate. More than most physicists realize, however, the way that mathematics is used in the course is foreign to a large portion of class. This paper puts forth an instructional model that can move all students toward better quantitative and physical reasoning, despite the substantial variability of those students' initial states. The third paper describes the design and testing of curricular materials that foster mathematical creativity to prepare students to better understand physics reasoning. Few students enter introductory physics with experience generating equations in response to specific challenges involving unfamiliar quantities and units, yet this generative use of mathematics is typical of the thinking involved in

Tragic mathematics: romantic narratives and the refounding of mathematics in the early nineteenth century.

PubMed

Alexander, Amir R

2006-12-01

A new, Romantic type of mathematical story appeared in the early nineteenth century that was radically different from the sober narrative characteristic of the previous generation of mathematicians. At the same time, a new mathematical practice emerged that differed sharply from the understanding and practice of mathematics during the Enlightenment. These parallel developments are inseparable: the new type of mathematical practice went hand in hand with the new mathematical story.

Practice; criteria; provisions; mathematical descriptions: Examples

NASA Astrophysics Data System (ADS)

Wijdieks, J.

1983-06-01

Waterhammer is defined as the appearance of pressure changes in closed conduits caused by velocity changes with time of the flow. Therefore waterhammer may occur in all kinds of pipelines in which flow changes occur over time: long or short pipelines for oil, sewage, drinking water, cooling water, slurry, coal slurry, chemicals, and in fresh water or city heating networks. The phenomenon of waterhammer is discussed herein. Specific parameters addressed include: the practical causes of waterhammer, cavitation flow, overpressure, vapor pressures, bulk modulus, continuous and discontinuous flow, and provisions to prevent waterhammer. Calculation of waterhammer is presented along with a mathematical description thereof. Hydraulic equipment (valves, pumps, surge towers) is also discussed.

Orientations toward Mathematical Processes of Prospective Secondary Mathematics Teachers as Related to Work with Tasks

ERIC Educational Resources Information Center

Cannon, Tenille

2016-01-01

Mathematics can be conceptualized in different ways. Policy documents such as the National Council of Teachers of Mathematics (NCTM) (2000) and the Common Core State Standards Initiative (CCSSI) (2010), classify mathematics in terms of mathematical content (e.g., quadratic functions, Pythagorean theorem) and mathematical activity in the form of…

HIDDEN DISPARITIES: HOW COURSES AND CURRICULA SHAPE OPPORTUNITIES IN MATHEMATICS DURING HIGH SCHOOL1

PubMed Central

Schiller, Kathryn S.; Schmidt, William H.; Muller, Chandra; Houang, Richard

2011-01-01

Efforts to promote academic achievement by increasing access to courses, especially in mathematics, may mask educational disparities if variations in curriculum are not also monitored. A multi-dimensional description of students’ mathematics curricula during high school was obtained from analyses of surveys, transcripts, and textbooks collected for a nationally representative study of adolescents during the mid-1990s. Few gaps in the number of years or credits in mathematics coursework were found. However, the quantity and cognitive challenge of instructional materials in textbooks adopted for those courses differed significantly both across and within mathematics tracks. Differences in the quality of curriculum accumulating during high school were also related to parents’ education level. Reducing such gaps in learning opportunities would require teachers to supplement adopted instructional materials to ensure that all students receive a high quality mathematics curriculum. PMID:23554547

Mathematics teachers' conceptions about modelling activities and its reflection on their beliefs about mathematics

NASA Astrophysics Data System (ADS)

Shahbari, Juhaina Awawdeh

2018-07-01

The current study examines whether the engagement of mathematics teachers in modelling activities and subsequent changes in their conceptions about these activities affect their beliefs about mathematics. The sample comprised 52 mathematics teachers working in small groups in four modelling activities. The data were collected from teachers' Reports about features of each activity, interviews and questionnaires on teachers' beliefs about mathematics. The findings indicated changes in teachers' conceptions about the modelling activities. Most teachers referred to the first activity as a mathematical problem but emphasized only the mathematical notions or the mathematical operations in the modelling process; changes in their conceptions were gradual. Most of the teachers referred to the fourth activity as a mathematical problem and emphasized features of the whole modelling process. The results of the interviews indicated that changes in the teachers' conceptions can be attributed to structure of the activities, group discussions, solution paths and elicited models. These changes about modelling activities were reflected in teachers' beliefs about mathematics. The quantitative findings indicated that the teachers developed more constructive beliefs about mathematics after engagement in the modelling activities and that the difference was significant, however there was no significant difference regarding changes in their traditional beliefs.

Making Mathematics.

ERIC Educational Resources Information Center

Huckstep, Peter

2002-01-01

Contends teachers must resist the temptation to suggest that, while children can create stories and melodies, they cannot create mathematics. Quotes mathematician G. H. Hardy: "A mathematician, like a painter or poet, is a 'maker' of patterns." Considers mathematics should be able to stand up for itself. (BT)

Helping Children Learn Mathematics through Multiple Intelligences and Standards for School Mathematics.

ERIC Educational Resources Information Center

Adams, Thomasenia Lott

2001-01-01

Focuses on the National Council of Teachers of Mathematics 2000 process-oriented standards of problem solving, reasoning and proof, communication, connections, and representation as providing a framework for using the multiple intelligences that children bring to mathematics learning. Presents ideas for mathematics lessons and activities to…

The Language of Mathematics: The Importance of Teaching and Learning Mathematical Vocabulary

ERIC Educational Resources Information Center

Riccomini, Paul J.; Smith, Gregory W.; Hughes, Elizabeth M.; Fries, Karen M.

2015-01-01

Vocabulary understanding is a major contributor to overall comprehension in many content areas, including mathematics. Effective methods for teaching vocabulary in all content areas are diverse and long standing. Teaching and learning the language of mathematics is vital for the development of mathematical proficiency. Students' mathematical…

Reciprocal Relationships between Mathematics Anxiety and Attitude towards Mathematics in Elementary Students

ERIC Educational Resources Information Center

Haciomeroglu, Guney

2017-01-01

This current study examined the reciprocal relationship between anxiety and attitude towards mathematics in elementary students. Two instruments (attitudes towards mathematics inventory short form [ATMI-Short Form] and the Revised Fennema-Sherman Mathematics Anxiety Scale [Revised-FSMAS]) were administered to 310 fourth grade elementary students.…

Mathematics Competency for Beginning Chemistry Students Through Dimensional Analysis.

PubMed

Pursell, David P; Forlemu, Neville Y; Anagho, Leonard E

2017-01-01

Mathematics competency in nursing education and practice may be addressed by an instructional variation of the traditional dimensional analysis technique typically presented in beginning chemistry courses. The authors studied 73 beginning chemistry students using the typical dimensional analysis technique and the variation technique. Student quantitative problem-solving performance was evaluated. Students using the variation technique scored significantly better (18.3 of 20 points, p < .0001) on the final examination quantitative titration problem than those who used the typical technique (10.9 of 20 points). American Chemical Society examination scores and in-house assessment indicate that better performing beginning chemistry students were more likely to use the variation technique rather than the typical technique. The variation technique may be useful as an alternative instructional approach to enhance beginning chemistry students' mathematics competency and problem-solving ability in both education and practice. [J Nurs Educ. 2017;56(1):22-26.]. Copyright 2017, SLACK Incorporated.

Reducing the Risk of Dangerous Chemicals Getting into the Wrong Hands

ERIC Educational Resources Information Center

Matthews, Nancy

2008-01-01

Under the Department of Homeland Security (DHS) Appropriations Act of 2007, DHS has the authority and funding to regulate security at facilities storing chemicals considered to be high-risk (P. L. 109-295, Section 550). This article discusses the Department's efforts to enhance the security of facilities that store chemicals that could be stolen…

Mathematics Self-Efficacy and Mistake-Handling Learning as Predictors of Mathematics Anxiety

ERIC Educational Resources Information Center

Aksu, Zeki; Ozkaya, Merve; Gedik, Solmaz Damla; Konyalioglu, Alper Cihan

2016-01-01

This study aims to analyze the relationship between secondary school seventh grade students' perception of mathematical self-efficacy, mistake-handling learning awareness, and mathematical anxiety; and to define the power of mistake-handling learning and self-efficacy in predicting mathematical anxiety. In this study, relational model was used and…

An Analysis of the Algebraic Method for Balancing Chemical Reactions.

ERIC Educational Resources Information Center

Olson, John A.

1997-01-01

Analyzes the algebraic method for balancing chemical reactions. Introduces a third general condition that involves a balance between the total amount of oxidation and reduction. Requires the specification of oxidation states for all elements throughout the reaction. Describes the general conditions, the mathematical treatment, redox reactions, and…

Incentivizing advanced mathematics study at upper secondary level: the case of bonus points in Ireland

NASA Astrophysics Data System (ADS)

Treacy, Páraic Thomas

2018-04-01

Secondary level mathematics education in Ireland has recently experienced a period of significant change with the introduction of new curricula and the addition of an incentive to study upper secondary mathematics at the most advanced level (Higher Level). This incentive, typically referred to as 'bonus points', appears to have aided a significant increase in the number of students studying upper secondary mathematics at Higher Level. However, thematic analysis of interviews with experienced upper secondary mathematics examiners and exploration of mathematics diagnostic test data outlined in this paper suggest that the difficulty of the Higher Level upper secondary mathematics final examination in Ireland has reduced since the introduction of the bonus points initiative. The sharp increase in students attempting this examination coupled with a policy of maintaining a consistent proportion of students achieving passing grades was identified as a key reason for this possible reduction in standards.

Identification of Chemical Toxicity Using Ontology Information of Chemicals.

PubMed

Jiang, Zhanpeng; Xu, Rui; Dong, Changchun

2015-01-01

With the advance of the combinatorial chemistry, a large number of synthetic compounds have surged. However, we have limited knowledge about them. On the other hand, the speed of designing new drugs is very slow. One of the key causes is the unacceptable toxicities of chemicals. If one can correctly identify the toxicity of chemicals, the unsuitable chemicals can be discarded in early stage, thereby accelerating the study of new drugs and reducing the R&D costs. In this study, a new prediction method was built for identification of chemical toxicities, which was based on ontology information of chemicals. By comparing to a previous method, our method is quite effective. We hope that the proposed method may give new insights to study chemical toxicity and other attributes of chemicals.

Symmetrical group theory for mathematical complexity reduction of digital holograms

NASA Astrophysics Data System (ADS)

Perez-Ramirez, A.; Guerrero-Juk, J.; Sanchez-Lara, R.; Perez-Ramirez, M.; Rodriguez-Blanco, M. A.; May-Alarcon, M.

2017-10-01

This work presents the use of mathematical group theory through an algorithm to reduce the multiplicative computational complexity in the process of creating digital holograms. An object is considered as a set of point sources using mathematical symmetry properties of both the core in the Fresnel integral and the image, where the image is modeled using group theory. This algorithm has multiplicative complexity equal to zero and an additive complexity ( k - 1) × N for the case of sparse matrices and binary images, where k is the number of pixels other than zero and N is the total points in the image.

Examining Mathematical Task and Pedagogical Usability of Web Contents Authored by Prospective Mathematics Teachers

ERIC Educational Resources Information Center

Akayuure, Peter; Apawu, Jones

2015-01-01

The study was designed to engage prospective mathematics teachers in creating web learning modules. The aim was to examine the mathematical task and perceived pedagogical usability of the modules for mathematics instructions in Ghana. The study took place at University of Education, Winneba. Classes of 172 prospective mathematics teachers working…

Time Spent on Homework, Mathematics Anxiety and Mathematics Achievement: Evidence from a US Sample

ERIC Educational Resources Information Center

Cheema, Jehanzeb R.; Sheridan, Kimberly

2015-01-01

This study investigated the effect of time spent on homework and mathematics anxiety on mathematics achievement. Data from a nationally representative US sample consisting of 4,978 cases was used to predict mathematics achievement from time spent on homework and mathematics anxiety while controlling for demographic differences such as gender,…

Deepening Pre-Service Secondary Teachers' Mathematical Content Knowledge through Engaging with Peers' Mathematical Contributions

ERIC Educational Resources Information Center

Pournara, C.

2016-01-01

Depth and rigour in mathematical knowledge for pre-service secondary school mathematics teachers may be found in particular experiences of learning and doing school-level mathematics. Drawing on two cases from a course on financial mathematics for secondary school teachers, I illustrate opportunities for exploring compound and exponential growth.…

Improving Mathematics Teaching in Kindergarten with Realistic Mathematical Education

ERIC Educational Resources Information Center

Papadakis, Stamatios; Kalogiannakis, Michail; Zaranis, Nicholas

2017-01-01

The present study investigates and compares the influence of teaching Realistic Mathematics on the development of mathematical competence in kindergarten. The sample consisted of 231 Greek kindergarten students. For the implementation of the survey, we conducted an intervention, which included one experimental and one control group. Children in…

General Mathematics; Part 1. Mathematics Curriculum Guide (Career Oriented).

ERIC Educational Resources Information Center

Nuschler, Alexandra; And Others

The curriculum guide for secondary level, career-oriented General Mathematics Part 1, correlates performance objectives in basic mathematics with career-oriented concepts and activities. The material is designed to lead the student in a systematic development that provides for continuous progress. The guide is in outline format, providing a…

Mathematics. [SITE 2001 Section].

ERIC Educational Resources Information Center

Connell, Michael L., Ed.; Lowery, Norene Vail, Ed.; Harnisch, Delwyn L., Ed.

This document contains the following papers on mathematics from the SITE (Society for Information Technology & Teacher Education) 2001 conference: "Secondary Mathematics Methods Course with Technology Units: Encouraging Pre-Service Teachers To Use Technology" (Rajee Amarasinghe); "Competency Exams in College Mathematics"…

Not mathematics Education, not Mathematics education but Mathematics Education

ERIC Educational Resources Information Center

Galbraith, P. L.

1977-01-01

Weaknesses in the initial preparation of school mathematics teachers are proposed. Emphasis is on the underdevelopment of global understanding in lieu of the manipulation of symbols or the performing of complex algorithms. (MN)

Long-term incorporation of manure with chemical fertilizers reduced total nitrogen loss in rain-fed cropping systems

PubMed Central

Duan, Yinghua; Xu, Minggang; Gao, Suduan; Liu, Hua; Huang, Shaomin; Wang, Boren

2016-01-01

Improving soil fertility/productivity and reducing environmental impact of nitrogen (N) fertilization are essential for sustainable agriculture. Quantifying the contribution of various fertilization regimes to soil N storage and loss has been lacking in a wide range of spatiotemporal scales. Based on data collected from field experiments at three typical agricultural zones in China, soil N dynamics and N changes in soil profile (0–100 cm) were examined during 1990–2009 under chemical fertilization, manure incorporation with fertilizer, and fertilizer with straw return treatments. We employed a mass balance approach to estimate the N loss to the environment after taking into account soil N change. Results showed a significant increase in soil N storage under manure incorporation treatments, accompanied with the lowest N loss (ave.20–24% of total N input) compared to all other treatments (ave.35–63%). Both soil N distribution and mass balance data suggested higher leaching risk from chemical fertilization in acidic soil of southern China with higher precipitation than the other two sites. This research concludes that manure incorporation with chemical fertilizer not only can achieve high N use efficiency and improve soil fertility, but also leads to the lowest total N loss or damage to the environment. PMID:27650801

Long-term incorporation of manure with chemical fertilizers reduced total nitrogen loss in rain-fed cropping systems.

PubMed

Duan, Yinghua; Xu, Minggang; Gao, Suduan; Liu, Hua; Huang, Shaomin; Wang, Boren

2016-09-21

Improving soil fertility/productivity and reducing environmental impact of nitrogen (N) fertilization are essential for sustainable agriculture. Quantifying the contribution of various fertilization regimes to soil N storage and loss has been lacking in a wide range of spatiotemporal scales. Based on data collected from field experiments at three typical agricultural zones in China, soil N dynamics and N changes in soil profile (0-100 cm) were examined during 1990-2009 under chemical fertilization, manure incorporation with fertilizer, and fertilizer with straw return treatments. We employed a mass balance approach to estimate the N loss to the environment after taking into account soil N change. Results showed a significant increase in soil N storage under manure incorporation treatments, accompanied with the lowest N loss (ave.20-24% of total N input) compared to all other treatments (ave.35-63%). Both soil N distribution and mass balance data suggested higher leaching risk from chemical fertilization in acidic soil of southern China with higher precipitation than the other two sites. This research concludes that manure incorporation with chemical fertilizer not only can achieve high N use efficiency and improve soil fertility, but also leads to the lowest total N loss or damage to the environment.

Chemical Hygiene Program

NASA Technical Reports Server (NTRS)

Mayor, Antoinette C.

1999-01-01

The Chemical Management Team is responsible for ensuring compliance with the OSHA Laboratory Standard. The program at Lewis Research Center (LeRC) evolved over many years to include training, developing Standard Operating Procedures (SOPS) for each laboratory process, coordinating with other safety and health organizations and teams at the Center, and issuing an SOP binder. The Chemical Hygiene Policy was first established for the Center. The Chemical Hygiene Plan was established and reviewed by technical, laboratory and management for viability and applicability to the Center. A risk assessment was conducted for each laboratory. The laboratories were prioritized by order of risk, higher risk taking priority. A Chemical Management Team staff member interviewed the lead researcher for each laboratory process to gather the information needed to develop the SOP for the process. A binder containing the Chemical Hygiene Plan, the SOP, a map of the laboratory identifying the personal protective equipment and best egress, and glove guides, as well as other guides for safety and health. Each laboratory process has been captured in the form of an SOP. The chemicals used in the procedure have been identified and the information is used to reduce the number of chemicals in the lab. The Chemical Hygiene Plan binder is used as a training tool for new employees. LeRC is in compliance with the OSHA Standard. The program was designed to comply with the OSHA standard. In the process, we have been able to assess the usage of chemicals in the laboratories, as well as reduce or relocate the chemicals being stored in the laboratory. Our researchers are trained on the hazards of the materials they work with and have a better understanding of the hazards of the process and what is needed to prevent any incident. From the SOP process, we have been able to reduce our chemical inventory, determine and implement better hygiene procedures and equipment in the laboratories, and provide

The contribution of executive functions to emergent mathematic skills in preschool children.

PubMed

Espy, Kimberly Andrews; McDiarmid, Melanie M; Cwik, Mary F; Stalets, Melissa Meade; Hamby, Arlena; Senn, Theresa E

2004-01-01

Mathematical ability is related to both activation of the prefrontal cortex in neuroimaging studies of adults and to executive functions in school-age children. The purpose of this study was to determine whether executive functions were related to emergent mathematical proficiency in preschool children. Preschool children (N = 96) were administered an executive function battery that was reduced empirically to working memory (WM), inhibitory control (IC), and shifting abilities by calculating composite scores derived from principal component analysis. Both WM and IC predicted early arithmetic competency, with the observed relations robust after controlling statistically for child age, maternal education, and child vocabulary. Only IC accounted for unique variance in mathematical skills, after the contribution of other executive functions were controlled statistically as well. Specific executive functions are related to emergent mathematical proficiency in this age range. Longitudinal studies using structural equation modeling are necessary to better characterize these ontogenetic relations.

Encouraging Young Women to Stay in the Mathematics Pipeline: Mathematics Camps for Young Women

ERIC Educational Resources Information Center

Chacon, Paul; Soto-Johnson, Hortensia

2003-01-01

For two summers, week-long residential mathematics programs were held for high school women, with the primary goal of encouraging them to continue their study of mathematics. The activities were designed to rekindle their excitement about mathematics and to support the idea that women should learn advanced mathematics. This paper reports the…

Mathematics Teacher Identity in the Context of Mathematics Reform: Elementary Teacher Experiences

ERIC Educational Resources Information Center

Sun, Jennifer

2017-01-01

Reform efforts and changes in mathematics education have brought on a shift towards a new vision of mathematics teaching in the United States. In light of recent accountability standards, the focus on teacher learning within the context of mathematics professional development is even more pressing. Prior research on teacher learning in the context…

Mathematics Teachers' Use of Ethnomathematics Approach in Mathematics Teaching in Edo State

ERIC Educational Resources Information Center

Aikpitanyi, Lucky Aiwuyor; Eraikhuemen, Lucy

2017-01-01

The study investigated mathematics teachers' use of ethnomathematics approach to teaching. Descriptive survey research was used with a target population of all mathematics teacher in all public secondary schools in Oredo, Egor and Ikpoba-Okha local government areas of Edo State out of which 121 mathematics teachers in 42 randomly selected public…

[Reducing nutrients loss by plastic film covering chemical fertilizers].

PubMed

Chen, Huo-jun; Wei, Ze-bin; Wu, Qi-tang; Zeng, Shu-cai

2010-03-01

With the low utilization rate of fertilizers by crop and the growing amount of fertilizer usage,the agricultural non-point source pollution in China is becoming more and more serious. The field experiments planting corns were conducted, in which the applied chemical fertilizers were recovered with plastic film to realize the separation of fertilizers from rain water. In the experiments, the influences of different fertilizing treatments on the growing and production of sweet corn were observed. The fertilizer utilization rate and the nutrient contents in surface run-off water with and without the film covering were also determined. Results showed that, with only 70% of the normal amount of fertilizers,the sweet corn could already get high yield under the experimental soil conditions. Soil analysis after corn crops showed that the amounts of available N, P and K in the soil increased obviously with the film-covering, and the decreasing order was: 100% fertilizers with film-covering > 70% fertilizers with film-covering > 100% fertilizers, 70% fertilizers > no fertilizer. The average utilization coefficients of fertilizers by the crop were 42%-87%, 0%-3%, 5%-15% respectively for N, P and K. It was higher with film-covering than that without covering, especially for the high fertilization treatment. Analysis of water samples collected for eight run-off events showed that, without film-covering, N, P and K average concentrations in the runoff waters with fertilizations were 27.72, 2.70 and 7.07 mg x L(-1), respectively. And they were reduced respectively by 39.54%, 28.05%, 43.74% with the film-covering. This can give significant benefits to the decrease of agricultural non-point source pollution and water eutrophication.

The impact of mathematical models of teaching materials on square and rectangle concepts to improve students' mathematical connection ability and mathematical disposition in middle school

NASA Astrophysics Data System (ADS)

Afrizal, Irfan Mufti; Dachlan, Jarnawi Afghani

2017-05-01

The aim of this study was to determine design of mathematical models of teaching materials to improve students' mathematical connection ability and mathematical disposition in middle school through experimental studies. The design in this study was quasi-experimental with non-equivalent control group type. This study consisted of two phases, the first phase was identify students' learning obstacle on square and rectangle concepts to obtain the appropriate design of teaching materials, beside that there were internalization of the values or characters expected to appear on students through the teaching materials. Second phase was experiments on the effectiveness and efficiency of mathematical models of teaching materials to improve students' mathematical connection ability and mathematical disposition. The result of this study are 1) Students' learning obstacle that have identified was categorized as an epistemological obstacle. 2) The improvement of students' mathematical connection ability and mathematical disposition who used mathematical teaching materials is better than the students who used conventional learning.

Mathematical Gossip: Relevance and Context in the Mathematics Classroom

ERIC Educational Resources Information Center

Callingham, Rosemary

2004-01-01

Using mathematical gossip in the classroom allows teachers to expand their students' horizons, and provide pathways to improvement of understanding. The expansion of a simple idea into another mathematical context can enrich a student's learning. In particular it may help to bridge the gap between purely procedural approaches and a conceptual…

Addressing the Mathematics-Specific Needs of Beginning Mathematics Teachers

ERIC Educational Resources Information Center

Britton, Edward

2012-01-01

Beginning mathematics teachers at the secondary level (middle and high school grades) have mathematics-specific needs that induction programs should address more substantially. However, a number of issues in how programs can accomplish this are more complex than often framed in discussions occurring in the induction programs and the field of…

Mathematical Power: Exploring Critical Pedagogy in Mathematics and Statistics

ERIC Educational Resources Information Center

Lesser, Lawrence M.; Blake, Sally

2007-01-01

Though traditionally viewed as value-free, mathematics is actually one of the most powerful, yet underutilized, venues for working towards the goals of critical pedagogy--social, political and economic justice for all. This emerging awareness is due to how critical mathematics educators such as Frankenstein, Skovsmose and Gutstein have applied the…

Conducting a Mathematics Camp for Girls & Other Mathematics Enthusiasts

ERIC Educational Resources Information Center

Wiest, Lynda

2008-01-01

Throughout much of the world, boys continue to outscore girls on standardized mathematics tests. For example, in most of the 57 countries that participated in the Programme for International Student Assessment (PISA) 2006, boys' performance was significantly higher than girls on the mathematics scale. This fact alone can harm girls' opportunities…

The influence of Missouri mathematics project on seventh grade students’ mathematical understanding ability

NASA Astrophysics Data System (ADS)

Rezeki, S.; Setyawan, A. A.; Amelia, S.

2018-01-01

Mathematical understanding ability is a primary goal of Indonesian national education goals. However, various sources has shown that Indonesian students’ mathematical understanding ability is still relatively low. This study used quasi-experimental research design to examine the effectiveness of the application of Missouri Mathematics Project (MMP) on students’ mathematical understanding ability. The participants of the study were seventh grade students in Pekanbaru, Riau Province, Indonesia. They were selected purposively and represented as high, medium, and low-quality schools. The result of this study indicated that there was a significant effect of MMP on the overall students’ mathematical understanding ability and in all categories, except for low school level.

A mathematical basis for plant patterning derived from physico-chemical phenomena.

PubMed

Beleyur, Thejasvi; Abdul Kareem, Valiya Kadavu; Shaji, Anil; Prasad, Kalika

2013-04-01

The position of leaves and flowers along the stem axis generates a specific pattern, known as phyllotaxis. A growing body of evidence emerging from recent computational modeling and experimental studies suggests that regulators controlling phyllotaxis are chemical, e.g. the plant growth hormone auxin and its dynamic accumulation pattern by polar auxin transport, and physical, e.g. mechanical properties of the cell. Here we present comprehensive views on how chemical and physical properties of cells regulate the pattern of leaf initiation. We further compare different computational modeling studies to understand their scope in reproducing the observed patterns. Despite a plethora of experimental studies on phyllotaxis, understanding of molecular mechanisms of pattern initiation in plants remains fragmentary. Live imaging of growth dynamics and physicochemical properties at the shoot apex of mutants displaying stable changes from one pattern to another should provide mechanistic insights into organ initiation patterns. Copyright © 2013 WILEY Periodicals, Inc.

Electromechanical Behavior of Chemically Reduced Graphene Oxide and Multi-walled Carbon Nanotube Hybrid Material

NASA Astrophysics Data System (ADS)

Benchirouf, Abderrahmane; Müller, Christian; Kanoun, Olfa

2016-01-01

In this paper, we propose strain-sensitive thin films based on chemically reduced graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) without adding any further surfactants. In spite of the insulating properties of the thin-film-based GO due to the presence functional groups such as hydroxyl, epoxy, and carbonyl groups in its atomic structure, a significant enhancement of the film conductivity was reached by chemical reduction with hydro-iodic acid. By optimizing the MWCNT content, a significant improvement of electrical and mechanical thin film sensitivity is realized. The optical properties and the morphology of the prepared thin films were studied using ultraviolet-visible spectroscopy (UV-Vis) and scanning electron microscope (SEM). The UV-Vis spectra showed the ability to tune the band gap of the GO by changing the MWCNT content, whereas the SEM indicated that the MWCNTs were well dissolved and coated by the GO. Investigations of the piezoresistive properties of the hybrid nanocomposite material under mechanical load show a linear trend between the electrical resistance and the applied strain. A relatively high gauge factor of 8.5 is reached compared to the commercial metallic strain gauges. The self-assembled hybrid films exhibit outstanding properties in electric conductivity, mechanical strength, and strain sensitivity, which provide a high potential for use in strain-sensing applications.

Electromechanical Behavior of Chemically Reduced Graphene Oxide and Multi-walled Carbon Nanotube Hybrid Material.

PubMed

Benchirouf, Abderrahmane; Müller, Christian; Kanoun, Olfa

2016-12-01

In this paper, we propose strain-sensitive thin films based on chemically reduced graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) without adding any further surfactants. In spite of the insulating properties of the thin-film-based GO due to the presence functional groups such as hydroxyl, epoxy, and carbonyl groups in its atomic structure, a significant enhancement of the film conductivity was reached by chemical reduction with hydro-iodic acid. By optimizing the MWCNT content, a significant improvement of electrical and mechanical thin film sensitivity is realized. The optical properties and the morphology of the prepared thin films were studied using ultraviolet-visible spectroscopy (UV-Vis) and scanning electron microscope (SEM). The UV-Vis spectra showed the ability to tune the band gap of the GO by changing the MWCNT content, whereas the SEM indicated that the MWCNTs were well dissolved and coated by the GO. Investigations of the piezoresistive properties of the hybrid nanocomposite material under mechanical load show a linear trend between the electrical resistance and the applied strain. A relatively high gauge factor of 8.5 is reached compared to the commercial metallic strain gauges. The self-assembled hybrid films exhibit outstanding properties in electric conductivity, mechanical strength, and strain sensitivity, which provide a high potential for use in strain-sensing applications.

The basic science and mathematics of random mutation and natural selection.

PubMed

Kleinman, Alan

2014-12-20

The mutation and natural selection phenomenon can and often does cause the failure of antimicrobial, herbicidal, pesticide and cancer treatments selection pressures. This phenomenon operates in a mathematically predictable behavior, which when understood leads to approaches to reduce and prevent the failure of the use of these selection pressures. The mathematical behavior of mutation and selection is derived using the principles given by probability theory. The derivation of the equations describing the mutation and selection phenomenon is carried out in the context of an empirical example. Copyright © 2014 John Wiley & Sons, Ltd.

A Mathematics Software Database Update.

ERIC Educational Resources Information Center

Cunningham, R. S.; Smith, David A.

1987-01-01

Contains an update of an earlier listing of software for mathematics instruction at the college level. Topics are: advanced mathematics, algebra, calculus, differential equations, discrete mathematics, equation solving, general mathematics, geometry, linear and matrix algebra, logic, statistics and probability, and trigonometry. (PK)

Applying an alternative mathematics pedagogy for students with weak mathematics: meta-analysis of alternative pedagogies

NASA Astrophysics Data System (ADS)

Lake, Warren; Wallin, Margie; Woolcott, Geoff; Boyd, Wendy; Foster, Alan; Markopoulos, Christos; Boyd, William

2017-02-01

Student mathematics performance and the need for work-ready graduates to be mathematics-competent is a core issue for many universities. While both student and teacher are responsible for learning outcomes, there is a need to explicitly acknowledge the weak mathematics foundation of many university students. A systematic literature review was undertaken of identified innovations and/or interventions that may lead to improvement in student outcomes for university mathematics-based units of study. The review revealed the importance of understanding the foundations of student performance in higher education mathematics learning, especially in first year. Pre-university mathematics skills were identified as significant in student retention and mathematics success at university, and a specific focus on student pre-university mathematics skill level was found to be more effective in providing help, rather than simply focusing on a particular at-risk group. Diagnostics tools were found to be important in identifying (1) student background and (2) appropriate intervention. The studies highlighted the importance of appropriate and validated interventions in mathematics teaching and learning, and the need to improve the learning model for mathematics-based subjects, communication and technology innovations.

Construction of Mathematical Knowledge Using Graphic Calculators (CAS) in the Mathematics Classroom

ERIC Educational Resources Information Center

Hitt, Fernando

2011-01-01

Mathematics education researchers are asking themselves about why technology has impacted heavily on the social environment and not in the mathematics classroom. The use of technology in the mathematics classroom has not had the expected impact, as it has been its use in everyday life (i.e. cell phone). What about teachers' opinions? Mathematics…

Reorganizing Freshman Business Mathematics II: Authentic Assessment in Mathematics through Professional Memos

ERIC Educational Resources Information Center

Green, Kris; Emerson, Allen

2008-01-01

The first part of this two-part paper [see EJ787497] described the development of a new freshman business mathematics (FBM) course at our college. In this paper, we discuss our assessment tool, the business memo, as a venue for students to apply mathematical skills, via mathematical modelling, to realistic business problems. These memos have…

The Role of Real-Life Mathematics Instruction on Mathematics Outcomes in Kindergarten

ERIC Educational Resources Information Center

Gottfried, Michael

2016-01-01

In an era of a declining quality and quantity of students entering and persisting in mathematics in the USA, researchers and policy makers are looking for new strategies to engage students in these fields and improve mathematics outcomes. One push has been to make mathematics instruction more relevant with real-world applications throughout the…

[Mathematical anatomy: muscles according to Stensen].

PubMed

Andrault, Raphaële

2010-01-01

In his Elementorum Myologiae Specimen, Steno geometrizes "the new fabric of muscles" and their movement of contraction, so as to refute the main contemporary hypothesis about the functioning of the muscles. This physiological refutation relies on an abstract representation of the muscular fibre as a parallelepiped of flesh transversally linked to the tendons. Those two features have been comprehensively studied. But the method used by Steno, as well as the way he has chosen to present his physiological results, have so far been neglected. Yet, Steno's work follows a true synthetic order, which he conceives as a tool to separate uncertain anatomical "elements" from the certain ones. We will show that the true understanding of this "more geometrico" order is the only way to avoid frequent misconceptions of the scientific aim pursued by Steno, which is neither to give a mathematical explanation of the functioning of the muscles, nor to reduce the muscles to some mathematical shapes.

The written mathematical communication profile of prospective math teacher in mathematical proving

NASA Astrophysics Data System (ADS)

Pantaleon, K. V.; Juniati, D.; Lukito, A.; Mandur, K.

2018-01-01

Written mathematical communication is the process of expressing mathematical ideas and understanding in writing. It is one of the important aspects that must be mastered by the prospective math teacher as tool of knowledge transfer. This research was a qualitative research that aimed to describe the mathematical communication profile of the prospective mathematics teacher in mathematical proving. This research involved 48 students of Mathematics Education Study Program; one of them with moderate math skills was chosen as the main subject. Data were collected through tests, assignments, and task-based interviews. The results of this study point out that in the proof of geometry, the subject explains what is understood, presents the idea in the form of drawing and symbols, and explains the content/meaning of a representation accurately and clearly, but the subject can not convey the argument systematically and logically. Whereas in the proof of algebra, the subject describes what is understood, explains the method used, and describes the content/meaning of a symbolic representation accurately, systematically, logically, but the argument presented is not clear because it is insufficient detailed and complete.

Mathematical Sciences in Australia

ERIC Educational Resources Information Center

Thomas, Jan; Muchatuta, Michelle; Wood, Leigh

2009-01-01

This article investigates enrolment trends in mathematical sciences in Australian universities. Data has been difficult to extract and the coding for mathematical disciplines has made investigation challenging. We show that the number of mathematics major undergraduates in Australia is steadily declining though the number studying…

Who Can Know Mathematics?

ERIC Educational Resources Information Center

Walshaw, Margaret

2014-01-01

This paper explores contemporary thinking about learning mathematics, and within that, social justice within mathematics education. The discussion first looks at mechanisms offered by conventional explanations on the emancipatory project and then moves towards more recent insights developed within mathematics education. Synergies are drawn between…

Correlates of Mathematics Anxiety.

ERIC Educational Resources Information Center

McCoy, Leah, P.

1992-01-01

Presents a survey of 78 pre- and in-service elementary teachers in a midwestern region to examine the relationship between mathematics anxiety, perceptual preference, and previous mathematics instructional experiences with workbooks and manipulatives. Results indicate that the variables significant in predicting mathematics anxiety were…

An integrated mathematical model for chemical oxygen demand (COD) removal in moving bed biofilm reactors (MBBR) including predation and hydrolysis.

PubMed

Revilla, Marta; Galán, Berta; Viguri, Javier R

2016-07-01

An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gender: Its relation to Mathematical Creative Thinking Skill

NASA Astrophysics Data System (ADS)

Permatasari, H. R.; Wahyudin, W.

2017-09-01

Mathematical creative thinking skill is one of the most important capabilities in the present century, both for men and women. One of the current issues is about gender and how gender mainstreaming can be realized optimally. The purpose of this study is to determine the comparison of the mathematical creative thinking skill increasing between male and female students after the application of Team Games Tournament (TGT) learning. This research was conducted at 28 students in the 4th grade of an elementary school in Bandung City. The research method used is quasi experiment because it is aimed to test wether there are differences in mathematical creative thinking skill improving between male and female students after being treatment in the form of learnig with TGT. The result of this research is that there is no difference in mathematical creative thinking skill improving between male and female students after the application of TGT learning. It is influenced by some factors such as how the teacher treats male and female with the same treatment in learning process. Recommendation of this research that can be done further research about this topic more deeply. Beside that, the teacher especially in elementary school can use the TGT learning application to reduce the gap between male and female students during the learning process.

Teacher's Guide to Secondary Mathematics.

ERIC Educational Resources Information Center

Duval County Schools, Jacksonville, FL.

This is a teacher's guide to secondary school mathematics. Developed for use in the Duval County Public Schools, Jacksonville, Florida. Areas of mathematics covered are algebra, analysis, calculus, computer literacy, computer science, geometry, analytic geometry, general mathematics, consumer mathematics, pre-algebra, probability and statistics,…

Truth & Beauty: Mathematics in Literature

ERIC Educational Resources Information Center

Cohen, Marion D.

2013-01-01

Today there are many categories of mathematics literature, including fiction and poetry. Mathematics fiction appears in such anthologies as "Fantasia Mathematica" (Fadiman 1958, 1997) and "The Mathematical Magpie" (Fadiman 1962, 1997). In addition, mathematics fiction is featured at http://kasmana.people.cofc.edu/MATHFICT.…

Theoretical Explanations in Mathematical Physics

NASA Astrophysics Data System (ADS)

Rivadulla, Andrés

Many physicists wonder at the usefulness of mathematics in physics. According Madrid to Einstein mathematics is admirably appropriate to the objects of reality. Wigner asserts that mathematics plays an unreasonable important role in physics. James Jeans affirms that God is a mathematician, and that the first aim of physics is to discover the laws of nature, which are written in mathematical language. Dirac suggests that God may have used very advanced mathematics in constructing the universe. And Barrow adheres himself to Wigner's claim about the unreasonable effectiveness of mathematics for the workings of the physical world.

Toothpastes containing abrasive and chemical whitening agents: efficacy in reducing extrinsic dental staining.

PubMed

Soares, Cristina Neves Girao Salgado; Amaral, Flavia Lucisano Botelho do; Mesquita, Marcelo Ferraz; Franca, Fabiana Mantovani Gomes; Basting, Roberta Tarkany; Turssi, Cecilia Pedroso

2015-01-01

This in vitro study evaluated the efficacy of toothpastes containing abrasive and chemical whitening agents in reducing the extrinsic discoloration of dental enamel. Sixty slabs of dentin from human teeth were sealed so that only the enamel surface was exposed. The enamel surfaces were photographed for initial color assessment. Staining was performed by immersing the dental slabs in 0.2% chlorhexidine solution for 2 minutes and then in black tea for 60 minutes. This process was repeated 15 times. Photographs were taken at the end of the staining process, and the slabs were divided into 5 groups (n = 12), 3 to be brushed with toothpastes containing chemical whitening agents (2 containing phosphate salts and 1 containing phosphate salts plus hydrogen peroxide) and 2 to represent control groups (ordinary/nonwhitening toothpaste and distilled water). The dental slabs were subjected to mechanical toothbrushing with toothpaste slurry or distilled water, according to each group's specifications. After brushing, more photographs were taken for color analysis. The results showed a significant reduction in luminosity after the staining process in addition to an increase in the colors red and yellow (P < 0.001). After brushing, there was a significant increase in luminosity and a reduction in both red and yellow (P < 0.001). However, there was no observed difference between the changes in color values in dental enamel slabs brushed with whitening toothpastes and the changes found in slabs brushed with ordinary toothpaste. The whitening toothpastes did not outperform an ordinary toothpaste in the removal of extrinsic staining.

QSAR modeling of cumulative environmental end-points for the prioritization of hazardous chemicals.

PubMed

Gramatica, Paola; Papa, Ester; Sangion, Alessandro

2018-01-24

The hazard of chemicals in the environment is inherently related to the molecular structure and derives simultaneously from various chemical properties/activities/reactivities. Models based on Quantitative Structure Activity Relationships (QSARs) are useful to screen, rank and prioritize chemicals that may have an adverse impact on humans and the environment. This paper reviews a selection of QSAR models (based on theoretical molecular descriptors) developed for cumulative multivariate endpoints, which were derived by mathematical combination of multiple effects and properties. The cumulative end-points provide an integrated holistic point of view to address environmentally relevant properties of chemicals.

Variation and Mathematics Pedagogy

ERIC Educational Resources Information Center

Leung, Allen

2012-01-01

This discussion paper put forwards variation as a theme to structure mathematical experience and mathematics pedagogy. Patterns of variation from Marton's Theory of Variation are understood and developed as types of variation interaction that enhance mathematical understanding. An idea of a discernment unit comprising mutually supporting variation…

Consequences, Characteristics, and Causes of Mathematical Learning Disabilities and Persistent Low Achievement in Mathematics

PubMed Central

Geary, David C.

2011-01-01

Objective The goals of the review are threefold; a) to highlight the educational and employment consequences of poorly developed mathematical competencies; b) overview the characteristics of the children with persistently low achievement in mathematics; and c) provide a primer on cognitive science research that is aimed at identifying the cognitive mechanisms underlying these learning disabilities and associated cognitive interventions. Method Literatures on the educational and economic consequences of poor mathematics achievement were reviewed and integrated with reviews of epidemiological, behavioral genetic, and cognitive science studies of poor mathematics achievement. Results Poor mathematical competencies are common among adults and result in employment difficulties and difficulties in many common day-to-day activities. Among students, about 7% of children and adolescents have a mathematical learning disability (MLD) and another 10% show persistent low achievement (LA) in mathematics despite average abilities in most other areas. Children with MLD and their LA peers have deficits in understanding and representing numerical magnitude, difficulties retrieving basic arithmetic facts from long-term memory, and delays in learning mathematical procedures. These deficits and delays cannot be attributed to intelligence, but are related to working memory deficits for children with MLD, but not LA children. Interventions that target these cognitive deficits are in development and preliminary results are promising. Conclusion Mathematical learning disabilities and learning difficulties associated with persistent low achievement in mathematics are common and not attributable to intelligence. These individuals have identifiable number and memory delays and deficits that appear to be specific to mathematics learning. The most promising interventions are those that target these specific deficits and, in addition, for children with MLD interventions that target their low

Discrete Mathematics and Curriculum Reform.

ERIC Educational Resources Information Center

Kenney, Margaret J.

1996-01-01

Defines discrete mathematics as the mathematics necessary to effect reasoned decision making in finite situations and explains how its use supports the current view of mathematics education. Discrete mathematics can be used by curriculum developers to improve the curriculum for students of all ages and abilities. (SLD)

Reaching All Students with Mathematics.

ERIC Educational Resources Information Center

Cuevas, Gilbert, Ed.; Driscoll, Mark, Ed.

The National Council of Teachers of Mathematics'"Curriculum and Evaluation Standards for School Mathematics" and "Professional Standards for Teaching Mathematics" reflect the belief that all students can learn a significant core of high-quality mathematics. Recognizing the magnitude of the task of reaching all students, this…

Mathematics reflecting sensorimotor organization.

PubMed

McCollum, Gin

2003-02-01

This review combines short presentations of several mathematical approaches that conceptualize issues in sensorimotor neuroscience from different perspectives and levels of analysis. The intricate organization of neural structures and sensorimotor performance calls for characterization using a variety of mathematical approaches. This review points out the prospects for mathematical neuroscience: in addition to computational approaches, there is a wide variety of mathematical approaches that provide insight into the organization of neural systems. By starting from the perspective that provides the greatest clarity, a mathematical approach avoids specificity that is inaccurate in characterizing the inherent biological organization. Approaches presented include the mathematics of ordered structures, motion-phase space, subject-coincident coordinates, equivalence classes, topological biodynamics, rhythm space metric, and conditional dynamics. Issues considered in this paper include unification of levels of analysis, response equivalence, convergence, relationship of physics to motor control, support of rhythms, state transitions, and focussing on low-dimensional subspaces of a high-dimensional sensorimotor space.

Moving toward Positive Mathematics Beliefs and Developing Socio-Mathematical Authority: Urban Preservice Teachers in Mathematics Methods Courses

ERIC Educational Resources Information Center

Saran, Rupam; Gujarati, Joan

2013-01-01

This article explores how preservice elementary teachers change their negative beliefs toward mathematics into positive ones after taking a mathematics methods course that follows the Concrete-Pictorial-Abstract (CPA) instructional method. Also explored is the relationship between those beliefs and sociomathematical authority. By administering…

[Mathematics - astronomy - astrology special library].

PubMed

Gluch, Sibylle

2011-01-01

About 1560 Elector August of Saxony created an unusual library--one distinguished within its period by both its specialization and location. Situated within the Kunstkammer this library was mostly dedicated to the mathematical sciences and related disciplines. It contained works by the most important authors on mathematics, astronomy, and astrology from the classical, medieval, and early modern periods. This essay traces the formation and composition of August's library, and examines its function: What kind of relationship existed between the library and the Kunstkammer? In what way did the library mirror the interests of the Elector, and to what extend does it permit inferences regarding the Elector's knowledge of mathematics? From the analysis August emerges not as a specialist with a deep understanding of mathematics, but as a particular aficionado of mathematical applications. As a practitioner and general follower of the mathematical arts he took part in a far-reaching intellectual network the center of which lay in the University of Wittenberg. Here, Melanchthon had effectively strengthened the importance of the mathematical disciplines within the university curriculum. He regarded mathematics as the foremost science, arguing that before all other disciplines its method enabled man to recognize the harmonic order of the world, and to discern divine providence. Thus, mathematics offered consoling stability and support in an often seemingly chaotic world torn by religious controversies. This kind of esteem for the mathematical sciences did not presuppose expert knowledge. Hence, the fact that August does not appear to have read the mathematical books he collected does not come as a contradiction. On the contrary, for August it sufficed to recognize the potential of the mathematical sciences, which he brought into life through the creation of a specialized library that developed a rhetoric of its own. The collection of his Kunstkammer library spoke of a

Opinions of Secondary School Mathematics Teachers on Mathematical Modelling

ERIC Educational Resources Information Center

Tutak, Tayfun; Güder, Yunus

2013-01-01

The aim of this study is to identify the opinions of secondary school mathematics teachers about mathematical modelling. Qualitative research was used. The participants of the study were 40 secondary school teachers working in the Bingöl Province in Turkey during 2012-2013 education year. Semi-structured interview form prepared by the researcher…

Explicit Mathematics Instruction: What Teachers Can Do for Teaching Students With Mathematics Difficulties

ERIC Educational Resources Information Center

Doabler, Christian T.; Fien, Hank

2013-01-01

This article describes the essential instructional elements necessary for delivering explicit mathematics instruction to students with mathematics difficulties. Mathematics intervention research indicates that explicit instruction is one of the most effective instructional approaches for teaching students with or at risk for math difficulties.…

Why Do Early Mathematics Skills Predict Later Reading? The Role of Mathematical Language

ERIC Educational Resources Information Center

Purpura, David J.; Logan, Jessica A. R.; Hassinger-Das, Brenna; Napoli, Amy R.

2017-01-01

A growing body of evidence indicates that the development of mathematics and literacy skills is highly related. The importance of literacy skills--specifically language--for mathematics development has been well rationalized. However, despite several prominent studies indicating that mathematics skills are highly predictive of literacy…

Semantic Processing of Mathematical Gestures

ERIC Educational Resources Information Center

Lim, Vanessa K.; Wilson, Anna J.; Hamm, Jeff P.; Phillips, Nicola; Iwabuchi, Sarina J.; Corballis, Michael C.; Arzarello, Ferdinando; Thomas, Michael O. J.

2009-01-01

Objective: To examine whether or not university mathematics students semantically process gestures depicting mathematical functions (mathematical gestures) similarly to the way they process action gestures and sentences. Semantic processing was indexed by the N400 effect. Results: The N400 effect elicited by words primed with mathematical gestures…

Internationalizing the Mathematical Finance Course

ERIC Educational Resources Information Center

Okonkwo, Zephyrinus C.

2017-01-01

About the year 2000, the Department of Mathematics and Computer Science, Albany State University (ASU), Albany, Georgia, USA envisioned the need to have a comprehensive curriculum revision based on recommendations of the Conference Boards of The Mathematical Sciences, the American Mathematical Society, the Mathematical Association of American, and…

Measuring Developmental Students' Mathematics Anxiety

ERIC Educational Resources Information Center

Ding, Yanqing

2016-01-01

This study conducted an item-level analysis of mathematics anxiety and examined the dimensionality of mathematics anxiety in a sample of developmental mathematics students (N = 162) by Multi-dimensional Random Coefficients Multinominal Logit Model (MRCMLM). The results indicate a moderately correlated factor structure of mathematics anxiety (r =…

The Relationship between Students' Performance on Conventional Standardized Mathematics Assessments and Complex Mathematical Modeling Problems

ERIC Educational Resources Information Center

Kartal, Ozgul; Dunya, Beyza Aksu; Diefes-Dux, Heidi A.; Zawojewski, Judith S.

2016-01-01

Critical to many science, technology, engineering, and mathematics (STEM) career paths is mathematical modeling--specifically, the creation and adaptation of mathematical models to solve problems in complex settings. Conventional standardized measures of mathematics achievement are not structured to directly assess this type of mathematical…

A Mathematical Diet Model

ERIC Educational Resources Information Center

Toumasis, Charalampos

2004-01-01

Emphasis on problem solving and mathematical modeling has gained considerable attention in the last few years. Connecting mathematics to other subjects and to the real world outside the classroom has received increased attention in mathematics programs. This article describes an application of simple differential equations in the field of…

Designing Online Mathematical Investigation

ERIC Educational Resources Information Center

Gadanidis, George; Sedig, Kamran; Liang, Hai-Ning

2004-01-01

In this paper we focus on interactive visualizations that support mathematical investigation. In the context of analyzing and redesigning an interactive visualization from the National Council of Teachers of Mathematics's (NCTM's) Illuminations Web site, we consider two interrelated issues: (1) how the pedagogy of mathematical investigation may be…

A Probablistic Diagram to Guide Chemical Design with Reduced Potency to Incur Cytotoxicity

EPA Science Inventory

Toxicity is a concern with many chemicals currently in commerce, and with new chemicals that are introduced each year. The standard approach to testing chemicals is to run studies in laboratory animals (e.g. rats, mice, dogs), but because of the expense of these studies and conce...

The Role of Gender, Self- and Task Perceptions in Mathematics and Science Participation among College Students.

ERIC Educational Resources Information Center

Lips, Hilary M.

The tendency of female students to avoid mathematics and science courses has been of concern to many researchers. The concern stems from the fact that avoidance of these academic areas places young women in a position of reduced choice with respect to careers. This research examined mathematics and science related attitudes and behaviors among…

Approaching mathematical model of the immune network based DNA Strand Displacement system.

PubMed

Mardian, Rizki; Sekiyama, Kosuke; Fukuda, Toshio

2013-12-01

One biggest obstacle in molecular programming is that there is still no direct method to compile any existed mathematical model into biochemical reaction in order to solve a computational problem. In this paper, the implementation of DNA Strand Displacement system based on nature-inspired computation is observed. By using the Immune Network Theory and Chemical Reaction Network, the compilation of DNA-based operation is defined and the formulation of its mathematical model is derived. Furthermore, the implementation on this system is compared with the conventional implementation by using silicon-based programming. From the obtained results, we can see a positive correlation between both. One possible application from this DNA-based model is for a decision making scheme of intelligent computer or molecular robot. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Mathematical Modeling: A Structured Process

ERIC Educational Resources Information Center

Anhalt, Cynthia Oropesa; Cortez, Ricardo

2015-01-01

Mathematical modeling, in which students use mathematics to explain or interpret physical, social, or scientific phenomena, is an essential component of the high school curriculum. The Common Core State Standards for Mathematics (CCSSM) classify modeling as a K-12 standard for mathematical practice and as a conceptual category for high school…

Finding Meaning in Mathematical Mnemonics

ERIC Educational Resources Information Center

Miller, Geoffrey; Obara, Samuel

2017-01-01

A mathematical mnemonic is a visual cue or verbal strategy that is used to aid initial memorisation and recall of a mathematical concept or procedure. Used wisely, mathematical mnemonics can benefit students' performance and understanding. Explorations into how mathematical mnemonics work can also offer students opportunities to engage in proof…

Rapid-mix and chemical quench studies of ferredoxin-reduced stearoyl-acyl carrier protein desaturase.

PubMed

Lyle, Karen S; Haas, Jeffrey A; Fox, Brian G

2003-05-20

Stearoyl-ACP Delta9 desaturase (Delta9D) catalyzes the NADPH- and O(2)-dependent insertion of a cis double bond between the C9 and C10 positions of stearoyl-ACP (18:0-ACP) to produce oleoyl-ACP (18:1-ACP). This work revealed the ability of reduced [2Fe-2S] ferredoxin (Fd) to act as a catalytically competent electron donor during the rapid conversion of 18:0-ACP into 18:1-ACP. Experiments on the order of addition for substrate and reduced Fd showed high conversion of 18:0-ACP to 18:1-ACP (approximately 95% per Delta9D active site in a single turnover) when 18:0-ACP was added prior to reduced Fd. Reactions of the prereduced enzyme-substrate complex with O(2) and the oxidized enzyme-substrate complex with reduced Fd were studied by rapid-mix and chemical quench methods. For reaction of the prereduced enzyme-substrate complex, an exponential burst phase (k(burst) = 95 s(-1)) of product formation accounted for approximately 90% of the turnover expected for one subunit in the dimeric protein. This rapid phase was followed by a slower phase (k(linear) = 4.0 s(-1)) of product formation corresponding to the turnover expected from the second subunit. For reaction of the oxidized enzyme-substrate complex with excess reduced Fd, a slower, linear rate (k(obsd) = 3.4 s(-1)) of product formation was observed over approximately 1.5 turnovers per Delta9D active site potentially corresponding to a third phase of reaction. An analysis of the deuterium isotope effect on the two rapid-mix reaction sequences revealed only a modest effect on k(burst) ((D)k(burst) approximately 1.5) and k(linear) (D)k(linear) approximately 1.4), indicating C-H bond cleavage does not contribute significantly to the rate-limiting steps of pre-steady-state catalysis. These results were used to assemble and evaluate a minimal kinetic model for Delta9D catalysis.

African American Mathematics Teachers as Agents in Their African American Students' Mathematics Identity Formation

ERIC Educational Resources Information Center

Clark, Lawrence M.; Badertscher, Eden M.; Napp, Carolina

2013-01-01

Background/Context: Recent research in mathematics education has employed sociocultural and historical lenses to better understand how students experience school mathematics and come to see themselves as capable mathematics learners. This work has identified mathematics classrooms as places where power struggles related to students'…

Beyond Motivation: Exploring Mathematical Modeling as a Context for Deepening Students' Understandings of Curricular Mathematics

ERIC Educational Resources Information Center

Zbiek, Rose Mary; Conner, Annamarie

2006-01-01

Views of mathematical modeling in empirical, expository, and curricular references typically capture a relationship between real-world phenomena and mathematical ideas from the perspective that competence in mathematical modeling is a clear goal of the mathematics curriculum. However, we work within a curricular context in which mathematical…

Mathematical Struggles and Ensuring Success: Post-Compulsory Mathematics as Preparation for Undergraduate Bioscience

ERIC Educational Resources Information Center

Bowyer, Jessica; Darlington, Ellie

2018-01-01

This article reports on data from a large-scale study investigating students' mathematical transitions to higher education. Three hundred and seventy-one undergraduate bioscientists were surveyed in order to investigate their perceptions and experiences of studying post-compulsory mathematics, as preparation for the mathematics elements of their…

Exploring Preservice Mathematics Teachers' Perception of the Mathematics Teacher through Communities of Practice

ERIC Educational Resources Information Center

Akkoç, Hatice; Balkanlioglu, Mehmet Ali; Yesildere-Imre, Sibel

2016-01-01

This research aimed to analyse the induction experiences of preservice mathematics teachers during their school placements through the lens of communities of practice. The main research question was concerned with how preservice mathematics teachers perceive what constitutes the practice of a professional community of mathematics teachers. A…

A New View of Mathematics Will Help Mathematics Teachers

ERIC Educational Resources Information Center

Maasz, Juergen

2005-01-01

For many people mathematics is something like a very huge and impressive building. It has a given structure with lots of levels and rooms. For many people this structure and therefore mathematics itself is independent from society, culture and history. It exists and mathematicians try to recover (not: to construct!) new parts of it. From this…

Modern Versus Traditional Mathematics

ERIC Educational Resources Information Center

Roberts, A. M.

1974-01-01

The effect of different secondary school mathematics syllabi on first-year performance in college-level mathematics was studied in an attempt to evaluate the syllabus change. Students with a modern mathematics background performed sigficantly better on most first-year units. A topic-by-topic analysis of results is included. (DT)

Mobile learning to improve mathematics teachers mathematical competencies

NASA Astrophysics Data System (ADS)

Hendrayana, A.; Wahyudin

2018-01-01

The role of teachers is crucial to the success of mathematics learning. One of the learning indicator is characterized by the students’ improved mathematical proficiency. In order to increase that, it is necessary to improve the teacher’s mathematical skills first. For that, it needs an innovative way to get teachers close to easily accessible learning resources through technology. The technology can facilitate teachers to access learning resources anytime and anywhere. The appropriate information technology is mobile learning. Innovations that can make teachers easy to access learning resources are mobile applications that can be accessed anytime and anywhere either online or offline. The research method was research development method. In preliminary analysis, subjects consist of teachers and lecturers in professional teacher education program. The results that the teachers ready to adopt mobile-learning for the improvement of their skills.

A Preservice Mathematics Teacher's Beliefs about Teaching Mathematics with Technology

ERIC Educational Resources Information Center

Belbase, Shashidhar

2015-01-01

This paper analyzed a preservice mathematics teacher's beliefs about teaching mathematics with technology. The researcher used five semi-structured task-based interviews in the problematic contexts of teaching fraction multiplications with JavaBars, functions and limits, and geometric transformations with Geometer's Sketchpad, and statistical data…

Alkaline deoxygenated graphene oxide for supercapacitor applications: An effective green alternative for chemically reduced graphene

NASA Astrophysics Data System (ADS)

Perera, Sanjaya D.; Mariano, Ruperto G.; Nijem, Nour; Chabal, Yves; Ferraris, John P.; Balkus, Kenneth J.

2012-10-01

Graphene is a promising electrode material for energy storage applications. The most successful method for preparing graphene from graphite involves the oxidation of graphite to graphene oxide (GO) and reduction back to graphene. Even though different chemical and thermal methods have been developed to reduce GO to graphene, the use of less toxic materials to generate graphene still remains a challenge. In this study we developed a facile one-pot synthesis of deoxygenated graphene (hGO) via alkaline hydrothermal process, which exhibits similar properties to the graphene obtained via hydrazine reduction (i.e. the same degree of deoxygenation found in hydrazine reduced GO). Moreover, the hGO formed freestanding, binder-free paper electrodes for supercapacitors. Coin cell type (CR2032) symmetric supercapacitors were assembled using the hGO electrodes. Electrochemical characterization of hGO was carried out using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and ethylmethylimidazolium bis-(trifluoromethanesulfonyl)imide (EMITFSI) electrolytes. The results for the hGO electrodes were compared with the hydrazine reduced GO (rGO) electrode. The hGO electrode exhibits a energy density of 20 W h kg-1 and 50 W h kg-1 in LiTFSI and EMITFSI respectively, while delivering a maximum power density of 11 kW kg-1 and 14.7 kW kg-1 in LiTFSI and EMITFSI, respectively.

Developmental Mathematics College Students' Experiences of Mathematical Practices in a 4-Week Summer Learning Community Using Local Communities of Mathematical Practice

ERIC Educational Resources Information Center

Naidu, Bhupinder

2013-01-01

The research literature concerning traditionally aged college mathematics students' who require remediation, in beginning Algebra topics, states that these students lack confidence in their mathematical skills, have experienced failure and frustration in the past, have low self confidence issues with respect to mathematics and often lack…

The Mathematical Sciences: A Report.

ERIC Educational Resources Information Center

National Academy of Sciences, Washington, DC.

Presented are position statements for the support of the mathematical sciences and a description of the present state of both research and education in mathematics and related disciplines. The report calls attention to the penetration of mathematics and mathematical modes of thought into many new areas of scholarship and the resultant increase in…

Science modelling in pre-calculus: how to make mathematics problems contextually meaningful

NASA Astrophysics Data System (ADS)

Sokolowski, Andrzej; Yalvac, Bugrahan; Loving, Cathleen

2011-04-01

'Use of mathematical representations to model and interpret physical phenomena and solve problems is one of the major teaching objectives in high school math curriculum' (National Council of Teachers of Mathematics (NCTM), Principles and Standards for School Mathematics, NCTM, Reston, VA, 2000). Commonly used pre-calculus textbooks provide a wide range of application problems. However, these problems focus students' attention on evaluating or solving pre-arranged formulas for given values. The role of scientific content is reduced to provide a background for these problems instead of being sources of data gathering for inducing mathematical tools. Students are neither required to construct mathematical models based on the contexts nor are they asked to validate or discuss the limitations of applied formulas. Using these contexts, the instructor may think that he/she is teaching problem solving, where in reality he/she is teaching algorithms of the mathematical operations (G. Kulm (ed.), New directions for mathematics assessment, in Assessing Higher Order Thinking in Mathematics, Erlbaum, Hillsdale, NJ, 1994, pp. 221-240). Without a thorough representation of the physical phenomena and the mathematical modelling processes undertaken, problem solving unintentionally appears as simple algorithmic operations. In this article, we deconstruct the representations of mathematics problems from selected pre-calculus textbooks and explicate their limitations. We argue that the structure and content of those problems limits students' coherent understanding of mathematical modelling, and this could result in weak student problem-solving skills. Simultaneously, we explore the ways to enhance representations of those mathematical problems, which we have characterized as lacking a meaningful physical context and limiting coherent student understanding. In light of our discussion, we recommend an alternative to strengthen the process of teaching mathematical modelling - utilization

Mathematical biology modules based on modern molecular biology and modern discrete mathematics.

PubMed

Robeva, Raina; Davies, Robin; Hodge, Terrell; Enyedi, Alexander

2010-01-01

We describe an ongoing collaborative curriculum materials development project between Sweet Briar College and Western Michigan University, with support from the National Science Foundation. We present a collection of modules under development that can be used in existing mathematics and biology courses, and we address a critical national need to introduce students to mathematical methods beyond the interface of biology with calculus. Based on ongoing research, and designed to use the project-based-learning approach, the modules highlight applications of modern discrete mathematics and algebraic statistics to pressing problems in molecular biology. For the majority of projects, calculus is not a required prerequisite and, due to the modest amount of mathematical background needed for some of the modules, the materials can be used for an early introduction to mathematical modeling. At the same time, most modules are connected with topics in linear and abstract algebra, algebraic geometry, and probability, and they can be used as meaningful applied introductions into the relevant advanced-level mathematics courses. Open-source software is used to facilitate the relevant computations. As a detailed example, we outline a module that focuses on Boolean models of the lac operon network.

Mathematical Biology Modules Based on Modern Molecular Biology and Modern Discrete Mathematics

PubMed Central

Davies, Robin; Hodge, Terrell; Enyedi, Alexander

2010-01-01

We describe an ongoing collaborative curriculum materials development project between Sweet Briar College and Western Michigan University, with support from the National Science Foundation. We present a collection of modules under development that can be used in existing mathematics and biology courses, and we address a critical national need to introduce students to mathematical methods beyond the interface of biology with calculus. Based on ongoing research, and designed to use the project-based-learning approach, the modules highlight applications of modern discrete mathematics and algebraic statistics to pressing problems in molecular biology. For the majority of projects, calculus is not a required prerequisite and, due to the modest amount of mathematical background needed for some of the modules, the materials can be used for an early introduction to mathematical modeling. At the same time, most modules are connected with topics in linear and abstract algebra, algebraic geometry, and probability, and they can be used as meaningful applied introductions into the relevant advanced-level mathematics courses. Open-source software is used to facilitate the relevant computations. As a detailed example, we outline a module that focuses on Boolean models of the lac operon network. PMID:20810955

Mathematics Attitudes and Mathematics Outcomes of U.S. and Belarusian Middle School Students

ERIC Educational Resources Information Center

Lipnevich, Anastasiya A.; MacCann, Carolyn; Krumm, Stefan; Burrus, Jeremy; Roberts, Richard D.

2011-01-01

Two multivariate studies examined the applicability of the theory of planned behavior in gauging students' attitudes toward mathematics, as well as the predictive power of mathematics attitudes in explaining students' grades in mathematics. Middle-school students from the United States (N = 382) and Belarus (N = 339) participated. Confirmatory…

The Effects of a Mathematics Infusion Curriculum on Middle School Student Mathematics Achievement

ERIC Educational Resources Information Center

Burghardt, M. David; Lauckhardt, James; Kennedy, Maria; Hecht, Deborah; McHugh, Luisa

2015-01-01

Increasing mathematical competencies of American students has been a focus for educators, researchers, and policy makers alike. One purported approach to increase student learning is through connecting mathematics and science curricula. Yet there is a lack of research examining the impact of making these connections. The Mathematics Infusion into…

Finnish Mentor Mathematics Teachers' Views of the Teacher Knowledge Required for Teaching Mathematics

ERIC Educational Resources Information Center

Asikainen, Mervi A.; Pehkonen, Erkki; Hirvonen, Pekka E.

2013-01-01

Seven Finnish mentor mathematics teachers were interviewed about their views regarding the teacher knowledge required for teaching mathematics. The results of the interviews revealed not only the teachers' spontaneous views of the knowledge base needed for effective mathematics teaching but also their views of the particular types of teacher…

pyJac: Analytical Jacobian generator for chemical kinetics

NASA Astrophysics Data System (ADS)

Niemeyer, Kyle E.; Curtis, Nicholas J.; Sung, Chih-Jen

2017-06-01

Accurate simulations of combustion phenomena require the use of detailed chemical kinetics in order to capture limit phenomena such as ignition and extinction as well as predict pollutant formation. However, the chemical kinetic models for hydrocarbon fuels of practical interest typically have large numbers of species and reactions and exhibit high levels of mathematical stiffness in the governing differential equations, particularly for larger fuel molecules. In order to integrate the stiff equations governing chemical kinetics, generally reactive-flow simulations rely on implicit algorithms that require frequent Jacobian matrix evaluations. Some in situ and a posteriori computational diagnostics methods also require accurate Jacobian matrices, including computational singular perturbation and chemical explosive mode analysis. Typically, finite differences numerically approximate these, but for larger chemical kinetic models this poses significant computational demands since the number of chemical source term evaluations scales with the square of species count. Furthermore, existing analytical Jacobian tools do not optimize evaluations or support emerging SIMD processors such as GPUs. Here we introduce pyJac, a Python-based open-source program that generates analytical Jacobian matrices for use in chemical kinetics modeling and analysis. In addition to producing the necessary customized source code for evaluating reaction rates (including all modern reaction rate formulations), the chemical source terms, and the Jacobian matrix, pyJac uses an optimized evaluation order to minimize computational and memory operations. As a demonstration, we first establish the correctness of the Jacobian matrices for kinetic models of hydrogen, methane, ethylene, and isopentanol oxidation (number of species ranging 13-360) by showing agreement within 0.001% of matrices obtained via automatic differentiation. We then demonstrate the performance achievable on CPUs and GPUs using py

Mathematics and Global Survival.

ERIC Educational Resources Information Center

Schwartz, Richard H.

This resource was written to provide students with an awareness of critical issues facing the world today. In courses for college students, it can motivate their study of mathematics, teach them how to solve mathematical problems related to current global issues, provide coherence to mathematical studies through a focus on issues of human…

Utah's New Mathematics Core

ERIC Educational Resources Information Center

Utah State Office of Education, 2011

2011-01-01

Utah has adopted more rigorous mathematics standards known as the Utah Mathematics Core Standards. They are the foundation of the mathematics curriculum for the State of Utah. The standards include the skills and understanding students need to succeed in college and careers. They include rigorous content and application of knowledge and reflect…

Teaching Mathematics as Agape

ERIC Educational Resources Information Center

Amidon, Joel C.

2011-01-01

What happens when the problem of inequitable access to mathematics is addressed by agape (pronounced agapa) or attending to the relationships students develop with mathematics? To respond to this question, this paper offers a description of the journey towards teaching mathematics as agape. First, I organized examples of equity pedagogy around the…

Mathematics, Programming, and STEM

ERIC Educational Resources Information Center

Yeh, Andy; Chandra, Vinesh

2015-01-01

Learning mathematics is a complex and dynamic process. In this paper, the authors adopt a semiotic framework (Yeh & Nason, 2004) and highlight programming as one of the main aspects of the semiosis or meaning-making for the learning of mathematics. During a 10- week teaching experiment, mathematical meaning-making was enriched when primary…

Learning Mathematics in High School Courses beyond Mathematics: Combating the Need for Post-Secondary Remediation in Mathematics

ERIC Educational Resources Information Center

Young, R. Brent; Hodge, Angie; Edwards, M. Craig; Leising, James G.

2012-01-01

The purpose of this study was to empirically test the posit that students who participated in a contextualized, mathematics-enhanced high school agricultural power and technology (APT) curriculum and aligned instructional approach would develop a deeper and more sustained understanding of selected mathematics concepts than those students who…

Propagation of Cutaneous Thermal Injury: A Mathematical Model

PubMed Central

Xue, Chuan; Chou, Ching-Shan; Kao, Chiu-Yen; Sen, Chandan K.; Friedman, Avner

2012-01-01

Cutaneous burn wounds represent a significant public health problem with 500,000 patients per year in the U.S. seeking medical attention. Immediately after skin burn injury, the volume of the wound burn expands due to a cascade of chemical reactions, including lipid peroxidation chain reactions. Based on these chemical reactions, the present paper develops for the first time a three-dimensional mathematical model to quantify the propagation of tissue damage within 12 hours post initial burn. We use the model to investigate the effect of supplemental antioxidant vitamin E for stopping the propagation. We show, for example, that if the production rate of vitamin E is increased, post burn, by five times the natural production in a healthy tissue, then this would slow down the lipid peroxide propagation by at least 50%. Our model is formulated in terms of differential equations, and sensitivity analysis is performed on the parameters to ensure the robustness of the results. PMID:22211391

Correlation of spacecraft thermal mathematical models to reference data

NASA Astrophysics Data System (ADS)

Torralbo, Ignacio; Perez-Grande, Isabel; Sanz-Andres, Angel; Piqueras, Javier

2018-03-01

Model-to-test correlation is a frequent problem in spacecraft-thermal control design. The idea is to determine the values of the parameters of the thermal mathematical model (TMM) that allows reaching a good fit between the TMM results and test data, in order to reduce the uncertainty of the mathematical model. Quite often, this task is performed manually, mainly because a good engineering knowledge and experience is needed to reach a successful compromise, but the use of a mathematical tool could facilitate this work. The correlation process can be considered as the minimization of the error of the model results with regard to the reference data. In this paper, a simple method is presented suitable to solve the TMM-to-test correlation problem, using Jacobian matrix formulation and Moore-Penrose pseudo-inverse, generalized to include several load cases. Aside, in simple cases, this method also allows for analytical solutions to be obtained, which helps to analyze some problems that appear when the Jacobian matrix is singular. To show the implementation of the method, two problems have been considered, one more academic, and the other one the TMM of an electronic box of PHI instrument of ESA Solar Orbiter mission, to be flown in 2019. The use of singular value decomposition of the Jacobian matrix to analyze and reduce these models is also shown. The error in parameter space is used to assess the quality of the correlation results in both models.

Time estimation predicts mathematical intelligence.

PubMed

Kramer, Peter; Bressan, Paola; Grassi, Massimo

2011-01-01

Performing mental subtractions affects time (duration) estimates, and making time estimates disrupts mental subtractions. This interaction has been attributed to the concurrent involvement of time estimation and arithmetic with general intelligence and working memory. Given the extant evidence of a relationship between time and number, here we test the stronger hypothesis that time estimation correlates specifically with mathematical intelligence, and not with general intelligence or working-memory capacity. Participants performed a (prospective) time estimation experiment, completed several subtests of the WAIS intelligence test, and self-rated their mathematical skill. For five different durations, we found that time estimation correlated with both arithmetic ability and self-rated mathematical skill. Controlling for non-mathematical intelligence (including working memory capacity) did not change the results. Conversely, correlations between time estimation and non-mathematical intelligence either were nonsignificant, or disappeared after controlling for mathematical intelligence. We conclude that time estimation specifically predicts mathematical intelligence. On the basis of the relevant literature, we furthermore conclude that the relationship between time estimation and mathematical intelligence is likely due to a common reliance on spatial ability.

Improved chemical and electrochemical stability of perovskite oxides with less reducible cations at the surface

DOE PAGES

Tsvetkov, Nikolai; Lu, Qiyang; Sun, Lixin; ...

2016-06-13

Segregation and phase separation of aliovalent dopants on perovskite oxide (ABO 3 ) surfaces are detrimental to the performance of energy conversion systems such as solid oxide fuel/electrolysis cells and catalysts for thermochemical H 2 O and CO 2 splitting. One key reason behind the instability of perovskite oxide surfaces is the electrostatic attraction of the negatively charged A-site dopants (for example, Sr La ') by the positively charged oxygen vacancies (Vmore » $$••\\atop{o}$$) enriched at the surface. Here we show that reducing the surface V $$••\\atop{o}$$ concentration improves the oxygen surface exchange kinetics and stability significantly, albeit contrary to the well-established understanding that surface oxygen vacancies facilitate reactions with O 2 molecules. We take La 0.8 Sr 0.2 CoO 3 (LSC) as a model perovskite oxide, and modify its surface with additive cations that are more and less reducible than Co on the B-site of LSC. By using ambient-pressure X-ray absorption and photoelectron spectroscopy, we proved that the dominant role of the less reducible cations is to suppress the enrichment and phase separation of Sr while reducing the concentration of V $$••\\atop{o}$$ and making the LSC more oxidized at its surface. Consequently, we found that these less reducible cations significantly improve stability, with up to 30 times faster oxygen exchange kinetics after 54 h in air at 530 °C achieved by Hf addition onto LSC. Finally, the results revealed a 'volcano' relation between the oxygen exchange kinetics and the oxygen vacancy formation enthalpy of the binary oxides of the additive cations. This volcano relation highlights the existence of an optimum surface oxygen vacancy concentration that balances the gain in oxygen exchange kinetics and the chemical stability loss.« less

Improved chemical and electrochemical stability of perovskite oxides with less reducible cations at the surface