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Sample records for posets disc math

  1. Webs and posets

    International Nuclear Information System (INIS)

    Dukes, M.; Gardi, E.; McAslan, H.; Scott, D.J.; White, C.D.

    2014-01-01

    The non-Abelian exponentiation theorem has recently been generalised to correlators of multiple Wilson line operators. The perturbative expansions of these correlators exponentiate in terms of sets of diagrams called webs, which together give rise to colour factors corresponding to connected graphs. The colour and kinematic degrees of freedom of individual diagrams in a web are entangled by mixing matrices of purely combinatorial origin. In this paper we relate the combinatorial study of these matrices to properties of partially ordered sets (posets), and hence obtain explicit solutions for certain families of web-mixing matrix, at arbitrary order in perturbation theory. We also provide a general expression for the rank of a general class of mixing matrices, which governs the number of independent colour factors arising from such webs. Finally, we use the poset language to examine a previously conjectured sum rule for the columns of web-mixing matrices which governs the cancellation of the leading subdivergences between diagrams in the web. Our results, when combined with parallel developments in the evaluation of kinematic integrals, offer new insights into the all-order structure of infrared singularities in non-Abelian gauge theories

  2. Sorting and selection in posets

    DEFF Research Database (Denmark)

    Daskalakis, Constantinos; Karp, Richard M.; Mossel, Elchanan

    2011-01-01

    from two decades ago by Faigle and Turán. In particular, we present the first algorithm that sorts a width-$w$ poset of size $n$ with query complexity $O(n(w+\\log n))$ and prove that this query complexity is asymptotically optimal. We also describe a variant of Mergesort with query complexity $O......(wn\\log\\frac{n}{w})$ and total complexity $O(w^{2}n\\log\\frac{n}{w})$; an algorithm with the same query complexity was given by Faigle and Turán, but no efficient implementation of that algorithm is known. Both our sorting algorithms can be applied with negligible overhead to the more general problem of reconstructing transitive......Classical problems of sorting and searching assume an underlying linear ordering of the objects being compared. In this paper, we study these problems in the context of partially ordered sets, in which some pairs of objects are incomparable. This generalization is interesting from a combinatorial...

  3. Poset limits can be totally ordered

    Czech Academy of Sciences Publication Activity Database

    Hladký, Jan; Máthé, A.; Viresh, P.; Pikhurko, O.

    2015-01-01

    Roč. 367, č. 6 (2015), s. 4319-4337 ISSN 0002-9947 Institutional support: RVO:67985840 Keywords : limits of discrete structures * regularity lemma * poset Subject RIV: BA - General Mathematics Impact factor: 1.196, year: 2015 http://www.ams.org/journals/tran/2015-367-06/S0002-9947-2015-06299-0/home.html

  4. Poset limits can be totally ordered

    Czech Academy of Sciences Publication Activity Database

    Hladký, Jan; Máthé, A.; Viresh, P.; Pikhurko, O.

    2015-01-01

    Roč. 367, č. 6 (2015), s. 4319-4337 ISSN 0002-9947 Institutional support: RVO:67985840 Keywords : limits of discrete structures * regularity lemma * poset Subject RIV: BA - General Mathematics Impact factor: 1.196, year: 2015 http://www.ams.org/journals/tran/2015-367-06/S0002-9947-2015-06299-0/ home .html

  5. Jauch-Piron orthomodular posets and propositional systems: A comparison

    Science.gov (United States)

    Piron, C.

    1993-10-01

    We compare the structures obtained via orthomodular posets and via propositional systems, discussing some examples of the links between them. Despite some analogies, the two structures are fundamentally different.

  6. Math

    CERN Document Server

    Robertson, William C

    2006-01-01

    Flummoxed by formulas? Queasy about equations? Perturbed by pi? Now you can stop cursing over calculus and start cackling over Math, the newest volume in Bill Robertson's accurate but amusing Stop Faking It! best sellers. As Robertson sees it, too many people view mathematics as a set of rules to be followed, procedures to memorize, and theorems to apply. This book focuses on the reasoning behind the rules, from math basics all the way up to a brief introduction to calculus.

  7. Meet and Join Matrices in the Poset of Exponential Divisors

    Indian Academy of Sciences (India)

    ... exponential divisor ( G C E D ) and the least common exponential multiple ( L C E M ) do not always exist. In this paper we embed this poset in a lattice. As an application we study the G C E D and L C E M matrices, analogues of G C D and L C M matrices, which are both special cases of meet and join matrices on lattices.

  8. Gerbes over posets and twisted C*-dynamical systems

    OpenAIRE

    Vasselli, Ezio

    2017-01-01

    A base $\\Delta$ generating the topology of a space $M$ becomes a partially ordered set (poset), when ordered under inclusion of open subsets. Given a precosheaf over $\\Delta$ of fixed-point spaces (typically C*-algebras) under the action of a group $G$, in general one cannot find a precosheaf of $G$-spaces having it as fixed-point precosheaf. Rather one gets a gerbe over $\\Delta$, that is, a "twisted precosheaf" whose twisting is encoded by a cocycle with coefficients in a suitable 2-group. W...

  9. A Framework for Coxeter Spectral Classification of Finite Posets and Their Mesh Geometries of Roots

    Directory of Open Access Journals (Sweden)

    Daniel Simson

    2013-01-01

    Full Text Available Following our paper [Linear Algebra Appl. 433(2010, 699–717], we present a framework and computational tools for the Coxeter spectral classification of finite posets J≡(J,⪯. One of the main motivations for the study is an application of matrix representations of posets in representation theory explained by Drozd [Funct. Anal. Appl. 8(1974, 219–225]. We are mainly interested in a Coxeter spectral classification of posets J such that the symmetric Gram matrix GJ:=(1/2[CJ+CJtr]∈J(ℚ is positive semidefinite, where CJ∈J(ℤ is the incidence matrix of J. Following the idea of Drozd mentioned earlier, we associate to J its Coxeter matrix CoxJ:=-CJ·CJ-tr, its Coxeter spectrum speccJ, a Coxeter polynomial coxJ(t∈ℤ[t], and a Coxeter number  cJ. In case GJ is positive semi-definite, we also associate to J a reduced Coxeter number   čJ, and the defect homomorphism ∂J:ℤJ→ℤ. In this case, the Coxeter spectrum speccJ is a subset of the unit circle and consists of roots of unity. In case GJ is positive semi-definite of corank one, we relate the Coxeter spectral properties of the posets J with the Coxeter spectral properties of a simply laced Euclidean diagram DJ∈{̃n,̃6,̃7,̃8} associated with J. Our aim of the Coxeter spectral analysis of such posets J is to answer the question when the Coxeter type CtypeJ:=(speccJ,cJ,  čJ of J determines its incidence matrix CJ (and, hence, the poset J uniquely, up to a ℤ-congruency. In connection with this question, we also discuss the problem studied by Horn and Sergeichuk [Linear Algebra Appl. 389(2004, 347–353], if for any ℤ-invertible matrix A∈n(ℤ, there is B∈n(ℤ such that Atr=Btr·A·B and B2=E is the identity matrix.

  10. Flow network QSAR for the prediction of physicochemical properties by mapping an electrical resistance network onto a chemical reaction poset.

    Science.gov (United States)

    Ivanciuc, Ovidiu; Ivanciuc, Teodora; Klein, Douglas J

    2013-06-01

    Usual quantitative structure-activity relationship (QSAR) models are computed from unstructured input data, by using a vector of molecular descriptors for each chemical in the dataset. Another alternative is to consider the structural relationships between the chemical structures, such as molecular similarity, presence of certain substructures, or chemical transformations between compounds. We defined a class of network-QSAR models based on molecular networks induced by a sequence of substitution reactions on a chemical structure that generates a partially ordered set (or poset) oriented graph that may be used to predict various molecular properties with quantitative superstructure-activity relationships (QSSAR). The network-QSAR interpolation models defined on poset graphs, namely average poset, cluster expansion, and spline poset, were tested with success for the prediction of several physicochemical properties for diverse chemicals. We introduce the flow network QSAR, a new poset regression model in which the dataset of chemicals, represented as a reaction poset, is transformed into an oriented network of electrical resistances in which the current flow results in a potential at each node. The molecular property considered in the QSSAR model is represented as the electrical potential, and the value of this potential at a particular node is determined by the electrical resistances assigned to each edge and by a system of batteries. Each node with a known value for the molecular property is attached to a battery that sets the potential on that node to the value of the respective molecular property, and no external battery is attached to nodes from the prediction set, representing chemicals for which the values of the molecular property are not known or are intended to be predicted. The flow network QSAR algorithm determines the values of the molecular property for the prediction set of molecules by applying Ohm's law and Kirchhoff's current law to the poset

  11. Talking Math, Blogging Math

    OpenAIRE

    Mathews, Linda Marie

    2009-01-01

    Talking Math, Blogging Math is a curriculum designed to aid middle school Pre- Algebra students' mathematical problem-solving through the use of academic language instruction, explanatory proofs, and online technology (blogging). Talking Math, Blogging Math was implemented over a period of ten weeks during the 2008 - 2009 school year. The school where the curriculum was implemented is a non-traditional classroom-based charter school. The 7th, 8th and 9th grade students attended class twice a ...

  12. Modern maths

    CERN Multimedia

    Thom,R

    1974-01-01

    Le Prof. R. Thom expose ses vues sur l'enseignement des mathématiques modernes et des mathémathiques de toujours. Il est un grand mathématicien et était professeur à Strasbourg; maintenant il est professeur de hautes études scientifiques et était invité par le Prof. Piaget à Genève

  13. Artificial Disc Replacement

    Science.gov (United States)

    ... Spondylolisthesis BLOG FIND A SPECIALIST Treatments Artificial Disc Replacement (ADR) Patient Education Committee Jamie Baisden The disc ... Disc An artificial disc (also called a disc replacement, disc prosthesis or spine arthroplasty device) is a ...

  14. Math Safari.

    Science.gov (United States)

    Nelson, Vaunda; Stanko, Anne

    1992-01-01

    Describes Math Safari, a mathematical, scientific, geographic, informational adventure for fourth grade students. It integrates all curriculum areas and other skills by using information children must find in books to pose math problems about animals. It encourages cooperative learning, critical reading, analysis, and use of research skills. (SM)

  15. Math Stuff

    CERN Document Server

    Pappas, Theoni

    2002-01-01

    Whether it's stuff in your kitchen or garden, stuff that powers your car or your body, stuff that helps you work, communicate or play, or stuff that you've never heard of you can bet that mathematics is there. MATH STUFF brings it all in the open in the Pappas style. Not many people think of mathematics as fascinating, exciting and invaluable. Yet Pappas writes about math ideas in such a way that conveys its often overlooked fascination, excitement, and worth. MATH STUFF deals with 38 topics in an non-threatening way that piques our curiosities. Open the book at random, and learn about such to

  16. Talking Maths

    Science.gov (United States)

    Murray, Jenny

    2006-01-01

    Discussion in maths lessons has always been something encouraged by ATM but can be difficult to initiate for non-specialist and inexperienced teachers who may feel they need material in books to get them going. In this article, the author describes resources aimed at encouraging discussion among primary mathematicians. These resources include: (1)…

  17. Penguin Math

    Science.gov (United States)

    Green, Daniel; Kearney, Thomas

    2015-01-01

    Emperor penguins, the largest of all the penguin species, attain heights of nearly four feet and weigh up to 99 pounds. Many students are not motivated to learn mathematics when textbook examples contain largely nonexistent contexts or when the math is not used to solve significant problems found in real life. This article's project explores how…

  18. Tangible Math

    Science.gov (United States)

    Scarlatos, Lori L.

    2006-01-01

    Educators recognize that group work and physical involvement with learning materials can greatly enhance the understanding and retention of difficult concepts. As a result, math manipulatives--such as pattern blocks and number lines--have increasingly been making their way into classrooms and children's museums. Yet without the constant guidance…

  19. Math Problem

    Science.gov (United States)

    Oguntoyinbo, Lekan

    2012-01-01

    Many experts give the nation's schools a poor grade for their approach to teaching mathematics and for their preparation of mathematics teachers. While many policymakers make much of data that suggest children in the United States lag behind many other advanced countries in math, many experts call for a change in mathematics education,…

  20. Working memory, math performance, and math anxiety.

    Science.gov (United States)

    Ashcraft, Mark H; Krause, Jeremy A

    2007-04-01

    The cognitive literature now shows how critically math performance depends on working memory, for any form of arithmetic and math that involves processes beyond simple memory retrieval. The psychometric literature is also very clear on the global consequences of mathematics anxiety. People who are highly math anxious avoid math: They avoid elective coursework in math, both in high school and college, they avoid college majors that emphasize math, and they avoid career paths that involve math. We go beyond these psychometric relationships to examine the cognitive consequences of math anxiety. We show how performance on a standardized math achievement test varies as a function of math anxiety, and that math anxiety compromises the functioning of working memory. High math anxiety works much like a dual task setting: Preoccupation with one's math fears and anxieties functions like a resource-demanding secondary task. We comment on developmental and educational factors related to math and working memory, and on factors that may contribute to the development of math anxiety.

  1. Disc defect classification for optical disc drives

    NARCIS (Netherlands)

    Helvoirt, van J.; Leenknegt, G.A.L.; Steinbuch, M.; Goossens, H.J.

    2005-01-01

    Optical disc drives are subject to various disturbances and faults. A special type of fault is the so-called disc defect. In this paper we present an approach for disc defect classification. It is based on hierarchical clustering of measured signals that are affected by disc defects. The

  2. Counseling the Math Anxious

    Science.gov (United States)

    Tobias, Sheila; Donady, Bonnie

    1977-01-01

    Describes the rationale and mode of operations for a Math Clinic at Wellesley University and Wesleyan College where counselors and math specialists work together to combat "math anxiety," particularly in female students. (HMV)

  3. Taking Math Anxiety out of Math Instruction

    Science.gov (United States)

    Shields, Darla J.

    2007-01-01

    To take math anxiety out of math instruction, teachers need to first know how to easily diagnose it in their students and second, how to analyze causes. Results of a recent study revealed that while students believed that their math anxiety was largely related to a lack of mathematical understanding, they often blamed their teachers for causing…

  4. Short-cut math

    CERN Document Server

    Kelly, Gerard W

    1984-01-01

    Clear, concise compendium of about 150 time-saving math short-cuts features faster, easier ways to add, subtract, multiply, and divide. Each problem includes an explanation of the method. No special math ability needed.

  5. Parent-child math anxiety and math-gender stereotypes predict adolescents' math education outcomes

    OpenAIRE

    Casad, Bettina J.; Hale, Patricia; Wachs, Faye L.

    2015-01-01

    Two studies examined social determinants of adolescents’ math anxiety including parents’ own math anxiety and children’s endorsement of math-gender stereotypes. In study 1, parent-child dyads were surveyed and the interaction between parent and child math anxiety was examined, with an eye to same- and other-gender dyads. Results indicate that parent’s math anxiety interacts with daughters’ and sons’ anxiety to predict math self-efficacy, GPA, behavioral intentions, math attitudes, and math de...

  6. Advanced Math Equals Career Readiness. Math Works

    Science.gov (United States)

    Achieve, Inc., 2013

    2013-01-01

    The equation is simple: No matter their background, students who take challenging math courses in high school get better jobs and earn more money throughout their entire lives. This paper stresses that: (1) Higher-level math opens doors for any and all postsecondary programs and keeps it open for advancement beyond entry-level jobs; and (2)…

  7. Teaching Math Their Way.

    Science.gov (United States)

    Tankersley, Karen

    1993-01-01

    Teachers at a K-8 urban school in Phoenix, Arizona, worked to develop an effective math program that generated student interest and positive self-esteem. They eventually set aside classroom and large enclosed porch area to house math manipulative lab, where children could learn new concepts at concrete level. Results are excitement about math and…

  8. Solving America's Math Problem

    Science.gov (United States)

    Vigdor, Jacob

    2013-01-01

    Concern about students' math achievement is nothing new, and debates about the mathematical training of the nation's youth date back a century or more. In the early 20th century, American high-school students were starkly divided, with rigorous math courses restricted to a college-bound elite. At midcentury, the "new math" movement sought,…

  9. Maths in Prison

    Directory of Open Access Journals (Sweden)

    Catherine Patricia Byrne

    2015-08-01

    Full Text Available I teach maths to all levels in an adult male remand prison in Ireland and am also studying for a PhD in maths in prison education in Dublin Institute of Technology (DIT. This paper describes recent initiatives piloted by maths teachers and school management to increase attendance, engagement and certification in maths. It assesses the effects of the initiatives and looks at future potential in this setting and in others. To set the paper in context, I begin by describing a typical day as a prison maths teacher.

  10. College Math Assessment: SAT Scores vs. College Math Placement Scores

    Science.gov (United States)

    Foley-Peres, Kathleen; Poirier, Dawn

    2008-01-01

    Many colleges and university's use SAT math scores or math placement tests to place students in the appropriate math course. This study compares the use of math placement scores and SAT scores for 188 freshman students. The student's grades and faculty observations were analyzed to determine if the SAT scores and/or college math assessment scores…

  11. Radially truncated galactic discs

    NARCIS (Netherlands)

    Grijs, R. de; Kregel, M.; Wesson, K H

    2000-01-01

    Abstract: We present the first results of a systematic analysis of radially truncatedexponential discs for four galaxies of a sample of disc-dominated edge-onspiral galaxies. Edge-on galaxies are very useful for the study of truncatedgalactic discs, since we can follow their light distributions out

  12. Female teachers' math anxiety affects girls' math achievement.

    Science.gov (United States)

    Beilock, Sian L; Gunderson, Elizabeth A; Ramirez, Gerardo; Levine, Susan C

    2010-02-02

    People's fear and anxiety about doing math--over and above actual math ability--can be an impediment to their math achievement. We show that when the math-anxious individuals are female elementary school teachers, their math anxiety carries negative consequences for the math achievement of their female students. Early elementary school teachers in the United States are almost exclusively female (>90%), and we provide evidence that these female teachers' anxieties relate to girls' math achievement via girls' beliefs about who is good at math. First- and second-grade female teachers completed measures of math anxiety. The math achievement of the students in these teachers' classrooms was also assessed. There was no relation between a teacher's math anxiety and her students' math achievement at the beginning of the school year. By the school year's end, however, the more anxious teachers were about math, the more likely girls (but not boys) were to endorse the commonly held stereotype that "boys are good at math, and girls are good at reading" and the lower these girls' math achievement. Indeed, by the end of the school year, girls who endorsed this stereotype had significantly worse math achievement than girls who did not and than boys overall. In early elementary school, where the teachers are almost all female, teachers' math anxiety carries consequences for girls' math achievement by influencing girls' beliefs about who is good at math.

  13. Maths in Prison

    OpenAIRE

    Catherine Patricia Byrne

    2015-01-01

    I teach maths to all levels in an adult male remand prison in Ireland and am also studying for a PhD in maths in prison education in Dublin Institute of Technology (DIT). This paper describes recent initiatives piloted by maths teachers and school management to increase attendance, engagement and certification in maths. It assesses the effects of the initiatives and looks at future potential in this setting and in others. To set the paper in context, I begin by describing a typical day as a ...

  14. Maths in Prison

    OpenAIRE

    Byrne, Catherine; Carr, Michael

    2015-01-01

    I teach maths to all levels in an adult male remand prison in Ireland and am also studying for a PhD in maths in prison education in Dublin Institute of Technology (DIT). This paper describes recent initiatives piloted by maths teachers and school management to increase attendance, engagement and certification in maths. It assesses the effects of the initiatives and looks at future potential in this setting and in others. To set the paper in context, I begin by describing a typical day as a p...

  15. Getting Manipulative about Math.

    Science.gov (United States)

    Scheer, Janet K.; And Others

    1984-01-01

    Math manipulatives that are made from inexpensive, common items help students understand basic mathematics concepts. Learning activities using Cheerios, jellybeans, and clay as teaching materials are suggested. (DF)

  16. GRE math tests

    CERN Document Server

    Kolby, Jeff

    2014-01-01

    Twenty-three GRE Math Tests! The GRE math section is not easy. There is no quick fix that will allow you to ""beat"" the section. But GRE math is very learnable. If you study hard and master the techniques in this book, your math score will improve--significantly! The GRE cannot be ""beaten."" But it can be mastered--through hard work, analytical thought, and by training yourself to think like a test writer. Many of the problems in this book are designed to prompt you to think like a test writer. For example, you will find ""Duals."" These are pairs of similar problems in which only one prop

  17. Dr Math at your service

    CSIR Research Space (South Africa)

    Butgereit, L

    2012-10-01

    Full Text Available In this presentation the author explains how the Dr Math service works; how tutors are recruited to act as Dr Math; and how school pupils can reach Dr Math for help with their mathematics homework....

  18. Evaluating the importance of surface soil contributions to reservoir sediment in alpine environments: a combined modelling and fingerprinting approach in the Posets-Maladeta Natural Park

    Science.gov (United States)

    Palazón, L.; Gaspar, L.; Latorre, B.; Blake, W. H.; Navas, A.

    2014-09-01

    Soil in alpine environments plays a key role in the development of ecosystem services and in order to maintain and preserve this important resource, information is required on processes that lead to soil erosion. Similar to other mountain alpine environments, the Benasque catchment is characterised by temperatures below freezing that can last from November to April, intense rainfall events, typically in spring and autumn, and rugged topography which makes assessment of erosion challenging. Indirect approaches to soil erosion assessment, such as combined model approaches, offer an opportunity to evaluate soil erosion in such areas. In this study (i) the SWAT (Soil and Water Assessment Tool) hydrological and erosion model and (ii) sediment fingerprinting procedures were used in parallel to assess the viability of a combined modelling and tracing approach to evaluate soil erosion processes in the area of the Posets-Maladeta Natural Park (central Spanish Pyrenees). Soil erosion rates and sediment contribution of potential sediment sources defined by soil type (Kastanozems/Phaeozems; Fluvisols and Cambisols) were assessed. The SWAT model suggested that, with the highest specific sediment yields, Cambisols are the main source of sediment in the Benasque catchment and Phaeozems and Fluvisols were identified as the lowest sediment contributors. Spring and winter model runs gave the highest and lowest specific sediment yield, respectively. In contrast, sediment fingerprinting analysis identified Fluvisols, which dominate the riparian zone, as the main sediment source at the time of sampling. This indicates the importance of connectivity as well as potential differences in the source dynamic of material in storage versus that transported efficiently from the system at times of high flow. The combined approach enabled us to better understand soil erosion processes in the Benasque alpine catchment, wherein SWAT identified areas of potential high sediment yield in large flood

  19. Parent-child math anxiety and math-gender stereotypes predict adolescents' math education outcomes

    Science.gov (United States)

    Casad, Bettina J.; Hale, Patricia; Wachs, Faye L.

    2015-01-01

    Two studies examined social determinants of adolescents' math anxiety including parents' own math anxiety and children's endorsement of math-gender stereotypes. In Study 1, parent-child dyads were surveyed and the interaction between parent and child math anxiety was examined, with an eye to same- and other-gender dyads. Results indicate that parent's math anxiety interacts with daughters' and sons' anxiety to predict math self-efficacy, GPA, behavioral intentions, math attitudes, and math devaluing. Parents with lower math anxiety showed a positive relationship to children's math outcomes when children also had lower anxiety. The strongest relationships were found with same-gender dyads, particularly Mother-Daughter dyads. Study 2 showed that endorsement of math-gender stereotypes predicts math anxiety (and not vice versa) for performance beliefs and outcomes (self-efficacy and GPA). Further, math anxiety fully mediated the relationship between gender stereotypes and math self-efficacy for girls and boys, and for boys with GPA. These findings address gaps in the literature on the role of parents' math anxiety in the effects of children's math anxiety and math anxiety as a mechanism affecting performance. Results have implications for interventions on parents' math anxiety and dispelling gender stereotypes in math classrooms. PMID:26579000

  20. Parent-Child Math Anxiety and Math-Gender Stereotypes Predict Adolescents’ Math Education Outcomes

    Directory of Open Access Journals (Sweden)

    Bettina J Casad

    2015-11-01

    Full Text Available Two studies examined social determinants of adolescents’ math anxiety including parents’ own math anxiety and children’s endorsement of math-gender stereotypes. In study 1, parent-child dyads were surveyed and the interaction between parent and child math anxiety was examined, with an eye to same- and other-gender dyads. Results indicate that parent’s math anxiety interacts with daughters’ and sons’ anxiety to predict math self-efficacy, GPA, behavioral intentions, math attitudes, and math devaluing. Parents with lower math anxiety showed a positive relationship to children’s math outcomes when children also had lower anxiety. The strongest relationships were found with same-gender dyads, particularly Mother-Daughter dyads. Study 2 showed that endorsement of math-gender stereotypes predicts math anxiety (and not vice versa for performance beliefs and outcomes (self-efficacy and GPA. Further, math anxiety fully mediated the relationship between gender stereotypes and math self-efficacy for girls and for boys, and for boys with GPA. These findings address gaps in the literature on the role of parents’ math anxiety in the effects of children’s math anxiety and math anxiety as a mechanism affecting performance. Results have implications for interventions on parents’ math anxiety and dispelling gender stereotypes in math classrooms.

  1. Parent-child math anxiety and math-gender stereotypes predict adolescents' math education outcomes.

    Science.gov (United States)

    Casad, Bettina J; Hale, Patricia; Wachs, Faye L

    2015-01-01

    Two studies examined social determinants of adolescents' math anxiety including parents' own math anxiety and children's endorsement of math-gender stereotypes. In Study 1, parent-child dyads were surveyed and the interaction between parent and child math anxiety was examined, with an eye to same- and other-gender dyads. Results indicate that parent's math anxiety interacts with daughters' and sons' anxiety to predict math self-efficacy, GPA, behavioral intentions, math attitudes, and math devaluing. Parents with lower math anxiety showed a positive relationship to children's math outcomes when children also had lower anxiety. The strongest relationships were found with same-gender dyads, particularly Mother-Daughter dyads. Study 2 showed that endorsement of math-gender stereotypes predicts math anxiety (and not vice versa) for performance beliefs and outcomes (self-efficacy and GPA). Further, math anxiety fully mediated the relationship between gender stereotypes and math self-efficacy for girls and boys, and for boys with GPA. These findings address gaps in the literature on the role of parents' math anxiety in the effects of children's math anxiety and math anxiety as a mechanism affecting performance. Results have implications for interventions on parents' math anxiety and dispelling gender stereotypes in math classrooms.

  2. The influence of experiencing success in math on math anxiety, perceived math competence, and math performance

    NARCIS (Netherlands)

    Jansen, B.R.J.; Louwerse, J.; Straatemeier, M.; van der Ven, S.H.G.; Klinkenberg, S.; van der Maas, H.L.J.

    2013-01-01

    It was investigated whether children would experience less math anxiety and feel more competent when they, independent of ability level, experienced high success rates in math. Comparable success rates were achieved by adapting problem difficulty to individuals' ability levels with a

  3. Barron's SAT math workbook

    CERN Document Server

    Leff MS, Lawrence S

    2016-01-01

    This completely revised edition reflects all of the new questions and question types that will appear on the new SAT, scheduled to be administered in Spring 2016. Includes hundreds of revised math questions and answer explanations, math strategies, test-taking tips, and much more.

  4. String Math 2017

    CERN Document Server

    The series of String-Math conferences has developed into a central event on the interface between mathematics and physics related to string theory, quantum field theory and neighboring subjects. The conference will take place from July 24-28 in the main building of Hamburg university. The String-Math conference is organised by the University of Hamburg jointly with DESY Hamburg.

  5. The Influence of Experiencing Success in Math on Math Anxiety, Perceived Math Competence, and Math Performance

    Science.gov (United States)

    Jansen, Brenda R. J.; Louwerse, Jolien; Straatemeier, Marthe; Van der Ven, Sanne H. G.; Klinkenberg, Sharon; Van der Maas, Han L. J.

    2013-01-01

    It was investigated whether children would experience less math anxiety and feel more competent when they, independent of ability level, experienced high success rates in math. Comparable success rates were achieved by adapting problem difficulty to individuals' ability levels with a computer-adaptive program. A total of 207 children (grades 3-6)…

  6. GRE math workbook

    CERN Document Server

    Madore, Blair

    2015-01-01

    Reflective of the current GRE, this third edition includes a description of the General Math Exam explaining structure, questions types, and scoring, strategies for problem solving, two full-length math sample sections structured to reflect the actual exam, answers thoroughly explained, and more.

  7. Superluminous accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M [Cambridge Univ. (UK). Inst. of Astronomy; Polska Akademia Nauk, Warsaw. Centrum Astronomiczne)

    1981-07-01

    Upper limits are computed for the total luminosities and collimation of radiation from thick, radiation supported accretion discs around black holes. Numerical results are obtained for the 'extreme' discs with rsub(out) = 10/sup 3/ GMsub(BH)/c/sup 2/, the angular momentum of the black hole being Jsub(BH) = 0.998 GMsub(BH)/c. The high luminosity (L approximately 8.5 Lsub(Edd)) and substantial collimation of radiation found for these discs indicate that such discs can explain both the high luminosities of quasars and similar objects and may produce some of the observed beams and jets.

  8. Flight Software Math Library

    Science.gov (United States)

    McComas, David

    2013-01-01

    The flight software (FSW) math library is a collection of reusable math components that provides typical math utilities required by spacecraft flight software. These utilities are intended to increase flight software quality reusability and maintainability by providing a set of consistent, well-documented, and tested math utilities. This library only has dependencies on ANSI C, so it is easily ported. Prior to this library, each mission typically created its own math utilities using ideas/code from previous missions. Part of the reason for this is that math libraries can be written with different strategies in areas like error handling, parameters orders, naming conventions, etc. Changing the utilities for each mission introduces risks and costs. The obvious risks and costs are that the utilities must be coded and revalidated. The hidden risks and costs arise in miscommunication between engineers. These utilities must be understood by both the flight software engineers and other subsystem engineers (primarily guidance navigation and control). The FSW math library is part of a larger goal to produce a library of reusable Guidance Navigation and Control (GN&C) FSW components. A GN&C FSW library cannot be created unless a standardized math basis is created. This library solves the standardization problem by defining a common feature set and establishing policies for the library s design. This allows the libraries to be maintained with the same strategy used in its initial development, which supports a library of reusable GN&C FSW components. The FSW math library is written for an embedded software environment in C. This places restrictions on the language features that can be used by the library. Another advantage of the FSW math library is that it can be used in the FSW as well as other environments like the GN&C analyst s simulators. This helps communication between the teams because they can use the same utilities with the same feature set and syntax.

  9. Motivation and Math Anxiety for Ability Grouped College Math Students

    Science.gov (United States)

    Helming, Luralyn

    2013-01-01

    The author studied how math anxiety, motivation, and ability group interact to affect performance in college math courses. This clarified the effects of math anxiety and ability grouping on performance. It clarified the interrelationships between math anxiety, motivation, and ability grouping by considering them in a single analysis. It introduces…

  10. Instability of warped discs

    Science.gov (United States)

    Doǧan, S.; Nixon, C. J.; King, A. R.; Pringle, J. E.

    2018-05-01

    Accretion discs are generally warped. If a warp in a disc is too large, the disc can `break' apart into two or more distinct planes, with only tenuous connections between them. Further, if an initially planar disc is subject to a strong differential precession, then it can be torn apart into discrete annuli that precess effectively independently. In previous investigations, torque-balance formulae have been used to predict where and when the disc breaks into distinct parts. In this work, focusing on discs with Keplerian rotation and where the shearing motions driving the radial communication of the warp are damped locally by turbulence (the `diffusive' regime), we investigate the stability of warped discs to determine the precise criterion for an isolated warped disc to break. We find and solve the dispersion relation, which, in general, yields three roots. We provide a comprehensive analysis of this viscous-warp instability and the emergent growth rates and their dependence on disc parameters. The physics of the instability can be understood as a combination of (1) a term that would generally encapsulate the classical Lightman-Eardley instability in planar discs (given by ∂(νΣ)/∂Σ < 0) but is here modified by the warp to include ∂(ν1|ψ|)/∂|ψ| < 0, and (2) a similar condition acting on the diffusion of the warp amplitude given in simplified form by ∂(ν2|ψ|)/∂|ψ| < 0. We discuss our findings in the context of discs with an imposed precession, and comment on the implications for different astrophysical systems.

  11. The Effects of Math Anxiety

    Science.gov (United States)

    Andrews, Amanda; Brown, Jennifer

    2015-01-01

    Math anxiety is a reoccurring problem for many students, and the effects of this anxiety on college students are increasing. The purpose of this study was to examine the association between pre-enrollment math anxiety, standardized test scores, math placement scores, and academic success during freshman math coursework (i.e., pre-algebra, college…

  12. Disc operational system

    International Nuclear Information System (INIS)

    Veretenov, V.Yu.; Volkov, A.I.; Gurevich, M.I.; Kozik, V.S.; Pod'yachev, E.I.; Shapiro, M.L.

    1974-01-01

    A disc operational system is proposed, which is based on the file structure and designed for use in a BESM-6 computer with the software system comprising a dispatcher DD-73 and a monitor 'Dubna'. The main distinguishing feature of the disc operational system is the decentralization of the file system. Each disc package is an independent file unaffected by the state of the other disc packages. The use of several disc packages is allowed. The above feature of the disc operational system makes it possible to simplify the language of communication with the system, to give the user the opportunity of controlling the file quite independently, and to simplify the maintenance of the discs by the computer personnel. One and the same disc can be simultaneously addressed by all problems in the processor (both mathematical and service). A single file, however, may be used in the recording mode by only one problem. The description presented is the instruction for users. It also describes special possibilities open to the system programmers [ru

  13. Intratracheal Seal Disc

    DEFF Research Database (Denmark)

    Christiansen, Karen J; Moeslund, Niels; Lauridsen, Henrik

    2017-01-01

    . The device consisted of an intratracheal silicone seal disc fixated by a cord through the stoma to an external part. At day 14, computed tomography (CT) was performed before the device was extracted. With the pulling of a cord, the disc unraveled into a thin thread and was extracted through the stoma. At day...

  14. SAT math prep course

    CERN Document Server

    Kolby, Jeff

    2011-01-01

    Comprehensive Prep for SAT Math Every year, students pay 1,000 and more to test prep companies to prepare for the math section of the new SAT. Now you can get the same preparation in a book. Features: * Comprehensive Review: Twenty-three chapters provide complete review of SAT math. * Practice: Includes 164 examples and more than 500 exercises! Arranged from easy to medium to hard to very hard. * Diagnostic Test: The diagnostic test measures your strengths and weaknesses and directs you to areas you need to study more. * Performance: If your target is a 700+ score, this is the book!

  15. More math into Latex

    CERN Document Server

    Grätzer, George

    2007-01-01

    For close to two decades, Math into Latex has been the standard introduction and complete reference for writing articles and books containing mathematical formulas. In this fourth edition, the reader is provided with important updates on articles and books. An important new topic is discussed: transparencies (computer projections). Key features of More Math into Latex, 4th edition: Installation instructions for PC and Mac users; An example-based, visual approach and a gentle introduction with the Short Course; A detailed exposition of multiline math formulas with a Visual Guide; A unified appr

  16. Double rupture disc experience

    International Nuclear Information System (INIS)

    1979-01-01

    Result of these observations, comparisons and evaluations can be summarized in the following list of concerns regarding the use of double rupture discs coupled to the liquid space of a steam generator that is subjected to a large leak sodium water reaction event. Single rupture disc show delayed collapse characteristics in LLTR Series I and double disc assemblies are presumed to be more complex with additional delay before opening to give pressure relief. Delayed failure increases pressures in the IHTS and must be adequately covered by design requirements. With CRBR design, the first disc may fail only partially reducing the loading on the second disc with the result that relief performance may not meet requirements

  17. Principals in Partnership with Math Coaches

    Science.gov (United States)

    Grant, Catherine Miles; Davenport, Linda Ruiz

    2009-01-01

    One of the most promising developments in math education is the fact that many districts are hiring math coaches--also called math resource teachers, math facilitators, math lead teachers, or math specialists--to assist elementary-level teachers with math instruction. What must not be lost, however, is that principals play an essential role in…

  18. A Study of Perceptions of Math Mindset, Math Anxiety, and View of Math by Young Adults

    Science.gov (United States)

    Hocker, Tami

    2017-01-01

    This study's purpose was to determine whether instruction in growth math mindset led to change in perceptions of 18-22-year-old at-risk students in math mindset, math anxiety, and view of math. The experimental curriculum was created by the researcher with the guidance of experts in mathematics and education and focused on the impact of brain…

  19. Optic disc oedema

    DEFF Research Database (Denmark)

    Nielsen, Marianne Kromann; Hamann, Steffen

    2014-01-01

    Optic disc oedema describes the nonspecific, localized swelling of the optic nerve head regardless of aetiology. Therefore, differentiating among the various aetiologies depends on a thorough history and knowledge of the clinical characteristics of the underlying conditions. Papilloedema strictly...... refers to optic disc oedema as a consequence of elevated intracranial pressure. It is usually a bilateral condition and visual function is preserved until late. Optic disc oedema caused by an anterior optic neuropathy is usually unilateral and accompanied by the loss of visual function....

  20. Herniated Cervical Disc

    Science.gov (United States)

    ... are sometimes prescribed for more severe arm and neck pain because of their very powerful anti-inflammatory effect. ... caused by a herniated cervical disc. However, some neck pain may persist. Most patients respond well to discectomy; ...

  1. La deglaciación de la alta montaña. Morfología, evolución y fases morfogenéticas glaciares en el macizo del Posets (Pirineo Aragonés)

    OpenAIRE

    Serrano Cañadas, Enrique; Agudo Garrido, Carlos; González Trueba, Juan José

    2002-01-01

    RESUMEN.El Posets es un macizo de alta montaña prácticamente deglaciado, donde las formas glaciares dominan en un medio crionival actual. Mediante la elaboración de la cartografía geomorfológica, la reconstrucción de las distintas fases glaciares y la estimación de los límites de equilibrio glaciar de cada fase, se establece la evolución de la deglaciación y la transición de un medio glaciar a periglaciar. Se han detectado cinco fases morfogenéticas principales en la alta montaña, Fase I, Ple...

  2. Math Anxiety and Math Ability in Early Primary School Years

    Science.gov (United States)

    Krinzinger, Helga; Kaufmann, Liane; Willmes, Klaus

    2010-01-01

    Mathematical learning disabilities (MLDs) are often associated with math anxiety, yet until now, very little is known about the causal relations between calculation ability and math anxiety during early primary school years. The main aim of this study was to longitudinally investigate the relationship between calculation ability, self-reported evaluation of mathematics, and math anxiety in 140 primary school children between the end of first grade and the middle of third grade. Structural equation modeling revealed a strong influence of calculation ability and math anxiety on the evaluation of mathematics but no effect of math anxiety on calculation ability or vice versa—contrasting with the frequent clinical reports of math anxiety even in very young MLD children. To summarize, our study is a first step toward a better understanding of the link between math anxiety and math performance in early primary school years performance during typical and atypical courses of development. PMID:20401159

  3. Math in Action. Hands-On, Minds-On Math.

    Science.gov (United States)

    Waite-Stupiansky, Sandra; Stupiansky, Nicholas G.

    1998-01-01

    Hands-on math must also involve students' minds in creative thinking. Math manipulatives must be used for uncovering, not just discovering. This paper presents guidelines for planning hands-on, minds-on math for elementary students. Suggestions include dialoging, questioning, integrating manipulatives and other tools, writing, and evaluating. (SM)

  4. An Annotated Math Lab Inventory.

    Science.gov (United States)

    Schussheim, Joan Yares

    1980-01-01

    A listing of mathematics laboratory material is organized as follows: learning kits, tape programs, manipulative learning materials, publications, math games, math lab library, and an alphabetized listing of publishers and/or companies offering materials. (MP)

  5. Culture and math.

    Science.gov (United States)

    Tcheang, Lili

    2014-01-01

    Cultural differences have been shown across a number of different cognitive domains from vision, language, and music. Mathematical cognition is another domain that is an integral part of modern society and because there are a fixed number of ways in which many math operations can be performed, it is also an apposite tool for cultural comparisons. This discussion examines the literature on mathematical processing in accordance with culture, summarizing the brain regions involved across various mathematical tasks. In doing so, we provide a clear picture of the anatomical similarities and differences between cultures when performing different math tasks. This information is useful to explore the possibility of enhancement of mathematical skills, where different strategies may be applicable in accordance with culture. It also contributes to the evolutionary development of different math skills and the growing theory that anatomical and behavioral studies must account for the cultural identity of their sample.

  6. Business math for dummies

    CERN Document Server

    Sterling, Mary Jane

    2008-01-01

    Now, it is easier than ever before to understand complex mathematical concepts and formulas and how they relate to real-world business situations. All you have to do it apply the handy information you will find in Business Math For Dummies. Featuring practical practice problems to help you expand your skills, this book covers topics like using percents to calculate increases and decreases, applying basic algebra to solve proportions, and working with basic statistics to analyze raw data. Find solutions for finance and payroll applications, including reading financial statements, calculating wages and commissions, and strategic salary planning. Navigate fractions, decimals, and percents in business and real estate transactions, and take fancy math skills to work. You'll be able to read graphs and tables and apply statistics and data analysis. You'll discover ways you can use math in finance and payroll investments, banking and payroll, goods and services, and business facilities and operations. You'll learn ho...

  7. When math hurts: math anxiety predicts pain network activation in anticipation of doing math.

    Directory of Open Access Journals (Sweden)

    Ian M Lyons

    Full Text Available Math can be difficult, and for those with high levels of mathematics-anxiety (HMAs, math is associated with tension, apprehension, and fear. But what underlies the feelings of dread effected by math anxiety? Are HMAs' feelings about math merely psychological epiphenomena, or is their anxiety grounded in simulation of a concrete, visceral sensation - such as pain - about which they have every right to feel anxious? We show that, when anticipating an upcoming math-task, the higher one's math anxiety, the more one increases activity in regions associated with visceral threat detection, and often the experience of pain itself (bilateral dorso-posterior insula. Interestingly, this relation was not seen during math performance, suggesting that it is not that math itself hurts; rather, the anticipation of math is painful. Our data suggest that pain network activation underlies the intuition that simply anticipating a dreaded event can feel painful. These results may also provide a potential neural mechanism to explain why HMAs tend to avoid math and math-related situations, which in turn can bias HMAs away from taking math classes or even entire math-related career paths.

  8. When Math Hurts: Math Anxiety Predicts Pain Network Activation in Anticipation of Doing Math

    Science.gov (United States)

    Lyons, Ian M.; Beilock, Sian L.

    2012-01-01

    Math can be difficult, and for those with high levels of mathematics-anxiety (HMAs), math is associated with tension, apprehension, and fear. But what underlies the feelings of dread effected by math anxiety? Are HMAs’ feelings about math merely psychological epiphenomena, or is their anxiety grounded in simulation of a concrete, visceral sensation – such as pain – about which they have every right to feel anxious? We show that, when anticipating an upcoming math-task, the higher one’s math anxiety, the more one increases activity in regions associated with visceral threat detection, and often the experience of pain itself (bilateral dorso-posterior insula). Interestingly, this relation was not seen during math performance, suggesting that it is not that math itself hurts; rather, the anticipation of math is painful. Our data suggest that pain network activation underlies the intuition that simply anticipating a dreaded event can feel painful. These results may also provide a potential neural mechanism to explain why HMAs tend to avoid math and math-related situations, which in turn can bias HMAs away from taking math classes or even entire math-related career paths. PMID:23118929

  9. When math hurts: math anxiety predicts pain network activation in anticipation of doing math.

    Science.gov (United States)

    Lyons, Ian M; Beilock, Sian L

    2012-01-01

    Math can be difficult, and for those with high levels of mathematics-anxiety (HMAs), math is associated with tension, apprehension, and fear. But what underlies the feelings of dread effected by math anxiety? Are HMAs' feelings about math merely psychological epiphenomena, or is their anxiety grounded in simulation of a concrete, visceral sensation - such as pain - about which they have every right to feel anxious? We show that, when anticipating an upcoming math-task, the higher one's math anxiety, the more one increases activity in regions associated with visceral threat detection, and often the experience of pain itself (bilateral dorso-posterior insula). Interestingly, this relation was not seen during math performance, suggesting that it is not that math itself hurts; rather, the anticipation of math is painful. Our data suggest that pain network activation underlies the intuition that simply anticipating a dreaded event can feel painful. These results may also provide a potential neural mechanism to explain why HMAs tend to avoid math and math-related situations, which in turn can bias HMAs away from taking math classes or even entire math-related career paths.

  10. Group Activities for Math Enthusiasts

    Science.gov (United States)

    Holdener, J.; Milnikel, R.

    2016-01-01

    In this article we present three group activities designed for math students: a balloon-twisting workshop, a group proof of the irrationality of p, and a game of Math Bingo. These activities have been particularly successful in building enthusiasm for mathematics and camaraderie among math faculty and students at Kenyon College.

  11. Is Math Anxiety Always Bad for Math Learning? The Role of Math Motivation.

    Science.gov (United States)

    Wang, Zhe; Lukowski, Sarah L; Hart, Sara A; Lyons, Ian M; Thompson, Lee A; Kovas, Yulia; Mazzocco, Michèle M M; Plomin, Robert; Petrill, Stephen A

    2015-12-01

    The linear relations between math anxiety and math cognition have been frequently studied. However, the relations between anxiety and performance on complex cognitive tasks have been repeatedly demonstrated to follow a curvilinear fashion. In the current studies, we aimed to address the lack of attention given to the possibility of such complex interplay between emotion and cognition in the math-learning literature by exploring the relations among math anxiety, math motivation, and math cognition. In two samples-young adolescent twins and adult college students-results showed inverted-U relations between math anxiety and math performance in participants with high intrinsic math motivation and modest negative associations between math anxiety and math performance in participants with low intrinsic math motivation. However, this pattern was not observed in tasks assessing participants' nonsymbolic and symbolic number-estimation ability. These findings may help advance the understanding of mathematics-learning processes and provide important insights for treatment programs that target improving mathematics-learning experiences and mathematical skills. © The Author(s) 2015.

  12. Business Math without Tears.

    Science.gov (United States)

    Merchant, Ronald

    1980-01-01

    Describes a new course at Spokane Falls Community College which builds on and reviews basic business math and electronic calculator skills. Material is self-paced and includes work with metrics. Discusses student evaluation of the course and type of equipment used. (CT)

  13. Where's the Math?

    Science.gov (United States)

    Texas Child Care, 2003

    2003-01-01

    Offers examples of materials and activities that promote and guide math-learning opportunities in all areas of the classroom. Materials and activities relate to: (1) art center; (2) science and discovery center; (3) blocks; (4) library and writing centers; (5) music and movement; (6) manipulatives; (7) dramatic play; (8) outdoor play; and (9)…

  14. Understand electrical and electronics maths

    CERN Document Server

    Bishop, Owen

    1993-01-01

    Understand Electrical and Electronics Maths covers elementary maths and the aspects of electronics. The book discusses basic maths including quotients, algebraic fractions, logarithms, types of equations and balancing of equations. The text also describes the main features and functions of graphs and the solutions to simpler types of electronics problems. The book then tackles the applications of polar coordinates in electronics, limits, differentiation and integration, and the applications of maths of rates of change in electronics. The activities of an electronic circuit; techniques of math

  15. The Galactic stellar disc

    International Nuclear Information System (INIS)

    Feltzing, S; Bensby, T

    2008-01-01

    The study of the Milky Way stellar discs in the context of galaxy formation is discussed. In particular, we explore the properties of the Milky Way disc using a new sample of about 550 dwarf stars for which we have recently obtained elemental abundances and ages based on high-resolution spectroscopy. For all the stars we also have full kinematic information as well as information about their stellar orbits. We confirm results from previous studies that the thin and the thick discs have distinct abundance patterns. But we also explore a larger range of orbital parameters than what has been possible in our previous studies. Several new results are presented. We find that stars that reach high above the Galactic plane and have eccentric orbits show remarkably tight abundance trends. This implies that these stars formed out of well-mixed gas that had been homogenized over large volumes. We find some evidence that suggest that the event that most likely caused the heating of this stellar population happened a few billion years ago. Through a simple, kinematic exploration of stars with super-solar [Fe/H], we show that the solar neighbourhood contains metal-rich, high velocity stars that are very likely associated with the thick disc. Additionally, the HR1614 moving group and the Hercules and Arcturus stellar streams are discussed and it is concluded that, probably, a large fraction of the groups and streams so far identified in the disc are the result of evolution and interactions within the stellar disc rather than being dissolved stellar clusters or engulfed dwarf galaxies.

  16. Isolated Optic Disc Tuberculosis

    Science.gov (United States)

    Mansour, Ahmad M.; Tabbara, Khalid F.; Tabbarah, Zuhair

    2015-01-01

    We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation. PMID:26483675

  17. Isolated Optic Disc Tuberculosis

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mansour

    2015-09-01

    Full Text Available We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation.

  18. Attentional Bias in Math Anxiety

    Directory of Open Access Journals (Sweden)

    Orly eRubinsten

    2015-10-01

    Full Text Available Cognitive theory from the field of general anxiety suggests that the tendency to display attentional bias toward negative information results in anxiety. Accordingly, the current study aims to investigate whether attentional bias is involved in math anxiety as well (i.e., a persistent negative reaction to math. Twenty seven participants (14 with high levels of math anxiety and 13 with low levels of math anxiety were presented with a novel computerized numerical version of the well established dot probe task. One of 6 types of prime stimuli, either math related or typically neutral, were presented on one side of a computer screen. The prime was preceded by a probe (either one or two asterisks that appeared in either the prime or the opposite location. Participants had to discriminate probe identity (one or two asterisks. Math anxious individuals reacted faster when the probe was at the location of the numerical related stimuli. This suggests the existence of attentional bias in math anxiety. That is, for math anxious individuals, the cognitive system selectively favored the processing of emotionally negative information (i.e., math related words. These findings suggest that attentional bias is linked to unduly intense math anxiety symptoms.

  19. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  20. String-math 2012

    CERN Document Server

    Katz, Sheldon; Klemm, Albrecht; Morrison, David R

    2015-01-01

    This volume contains the proceedings of the conference String-Math 2012, which was held July 16-21, 2012, at the Hausdorff Center for Mathematics, Universitat Bonn. This was the second in a series of annual large meetings devoted to the interface of mathematics and string theory. These meetings have rapidly become the flagship conferences in the field. Topics include super Riemann surfaces and their super moduli, generalized moonshine and K3 surfaces, the latest developments in supersymmetric and topological field theory, localization techniques, applications to knot theory, and many more. The contributors include many leaders in the field, such as Sergio Cecotti, Matthias Gaberdiel, Rahul Pandharipande, Albert Schwarz, Anne Taormina, Johannes Walcher, Katrin Wendland, and Edward Witten. This book will be essential reading for researchers and students in this area and for all mathematicians and string theorists who want to update themselves on developments in the math-string interface.

  1. Technical Math For Dummies

    CERN Document Server

    Schoenborn, Barry

    2010-01-01

    Technical Math For Dummies is your one-stop, hands-on guide to acing the math courses you’ll encounter as you work toward getting your degree, certifacation, or�license in the skilled trades. You’ll get easy-to-follow, plain-English guidance on mathematical formulas and methods that professionals use every day in the automotive, health, construction, licensed trades, maintenance, and other trades. You’ll learn how to apply concepts of algebra, geometry, and trigonometry and their formulas related to occupational areas of study. Plus, you’ll find out how to perform basic arithmetic

  2. Contact dynamics math model

    Science.gov (United States)

    Glaese, John R.; Tobbe, Patrick A.

    1986-01-01

    The Space Station Mechanism Test Bed consists of a hydraulically driven, computer controlled six degree of freedom (DOF) motion system with which docking, berthing, and other mechanisms can be evaluated. Measured contact forces and moments are provided to the simulation host computer to enable representation of orbital contact dynamics. This report describes the development of a generalized math model which represents the relative motion between two rigid orbiting vehicles. The model allows motion in six DOF for each body, with no vehicle size limitation. The rotational and translational equations of motion are derived. The method used to transform the forces and moments from the sensor location to the vehicles' centers of mass is also explained. Two math models of docking mechanisms, a simple translational spring and the Remote Manipulator System end effector, are presented along with simulation results. The translational spring model is used in an attempt to verify the simulation with compensated hardware in the loop results.

  3. All Students Need Advanced Mathematics. Math Works

    Science.gov (United States)

    Achieve, Inc., 2013

    2013-01-01

    This fact sheet explains that to thrive in today's world, all students will need to graduate with very strong math skills. That can only mean one thing: advanced math courses are now essential math courses. Highlights of this paper include: (1) Advanced math equals college success; (2) Advanced math equals career opportunity; and (3) Advanced math…

  4. Financial Statement Math

    OpenAIRE

    2007-01-01

    game tool Game Tool Interactive Media Element The purpose of this interactive exercise is to help you understand the math in the income statement and balance sheet., Give the proper mathematical computations in order to correctly prepare the income statement and the balance sheet.The exercise is divided into 3 parts: The income Statement, The Balance Sheet - Assets, The Balance Sheet - Liabilities, GB3050 Financial Reporting and Analysis

  5. MathSci

    OpenAIRE

    De Robbio, Antonella

    1997-01-01

    This paper shows the prestigious mathematics database MathSci, produced by American Mathematical Society (AMS). It is an indexing resource that deals with the whole literature about mathematics. The subject involved in referred to mathematical sciences and others relating such as Statistics, Information science, Operative research and Mathematics Physics. Moreover it indexes sciences related to applied mathematics such as Astronomy, Astrophysics, Biology, Compartmental Sciences, Thermodyn...

  6. The role of self-math overlap in understanding math anxiety and the relation between math anxiety and performance.

    Science.gov (United States)

    Necka, Elizabeth A; Sokolowski, H Moriah; Lyons, Ian M

    2015-01-01

    Recent work has demonstrated that math anxiety is more than just the product of poor math skills. Psychosocial factors may play a key role in understanding what it means to be math anxious, and hence may aid in attempts to sever the link between math anxiety and poor math performance. One such factor may be the extent to which individuals integrate math into their sense of self. We adapted a well-established measure of this degree of integration (i.e., self-other overlap) to assess individuals' self-math overlap. This non-verbal single-item measure showed that identifying oneself with math (having higher self-math overlap) was strongly associated with lower math anxiety (r = -0.610). We also expected that having higher self-math overlap would leave one especially susceptible to the threat of poor math performance to the self. We identified two competing hypotheses regarding how this plays out in terms of math anxiety. Those higher in self-math overlap might be more likely to worry about poor math performance, exacerbating the negative relation between math anxiety and math ability. Alternatively, those higher in self-math overlap might exhibit self-serving biases regarding their math ability, which would instead predict a decoupling of the relation between their perceived and actual math ability, and in turn the relation between their math ability and math anxiety. Results clearly favored the latter hypothesis: those higher in self-math overlap exhibited almost no relation between math anxiety and math ability, whereas those lower in self-math overlap showed a strong negative relation between math anxiety and math ability. This was partially explained by greater self-serving biases among those higher in self-math overlap. In sum, these results reveal that the degree to which one integrates math into one's self - self-math overlap - may provide insight into how the pernicious negative relation between math anxiety and math ability may be ameliorated.

  7. The role of self-math overlap in understanding math anxiety and the relation between math anxiety and performance

    Science.gov (United States)

    Necka, Elizabeth A.; Sokolowski, H. Moriah; Lyons, Ian M.

    2015-01-01

    Recent work has demonstrated that math anxiety is more than just the product of poor math skills. Psychosocial factors may play a key role in understanding what it means to be math anxious, and hence may aid in attempts to sever the link between math anxiety and poor math performance. One such factor may be the extent to which individuals integrate math into their sense of self. We adapted a well-established measure of this degree of integration (i.e., self-other overlap) to assess individuals’ self-math overlap. This non-verbal single-item measure showed that identifying oneself with math (having higher self-math overlap) was strongly associated with lower math anxiety (r = -0.610). We also expected that having higher self-math overlap would leave one especially susceptible to the threat of poor math performance to the self. We identified two competing hypotheses regarding how this plays out in terms of math anxiety. Those higher in self-math overlap might be more likely to worry about poor math performance, exacerbating the negative relation between math anxiety and math ability. Alternatively, those higher in self-math overlap might exhibit self-serving biases regarding their math ability, which would instead predict a decoupling of the relation between their perceived and actual math ability, and in turn the relation between their math ability and math anxiety. Results clearly favored the latter hypothesis: those higher in self-math overlap exhibited almost no relation between math anxiety and math ability, whereas those lower in self-math overlap showed a strong negative relation between math anxiety and math ability. This was partially explained by greater self-serving biases among those higher in self-math overlap. In sum, these results reveal that the degree to which one integrates math into one’s self – self-math overlap – may provide insight into how the pernicious negative relation between math anxiety and math ability may be ameliorated. PMID

  8. The role of self-math overlap in understanding math anxiety and the relation between math anxiety and performance

    Directory of Open Access Journals (Sweden)

    Elizabeth A Necka

    2015-10-01

    Full Text Available Recent work has demonstrated that math anxiety is more than just the product of poor math skills. Psychosocial factors may play a key role in understanding what it means to be math anxious, and hence may aid in attempts to sever the link between math anxiety and poor math performance. One such factor may be the extent to which individuals integrate math into their sense of self. We adapted a well-established measure of this degree of integration (i.e., self-other overlap to assess individuals’ self-math overlap. This nonverbal single-item measure showed that identifying oneself with math (having higher self-math overlap was strongly associated with lower math anxiety (r=-.610. We also expected that having higher self-math overlap would leave one especially susceptible to the threat of poor math performance to the self. We identified two competing hypotheses regarding how this plays out in terms of math anxiety. Those higher in self-math overlap might be more likely to worry about poor math performance, exacerbating the negative relation between math anxiety and math ability. Alternatively, those higher in self-math overlap might exhibit self-serving biases regarding their math ability, which would instead predict a decoupling of the relation between their perceived and actual math ability, and in turn the relation between their math ability and math anxiety. Results clearly favored the latter hypothesis: those higher in self-math overlap exhibited almost no relation between math anxiety and math ability, whereas those lower in self-math overlap showed a strong negative relation between math anxiety and math ability. This was partially explained by greater self-serving biases among those higher in self-math overlap. In sum, these results reveal that the degree to which one integrates math into one’s self – self-math overlap – may provide insight into how the pernicious negative relation between math anxiety and math ability may be

  9. Wave disc engine apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Norbert; Piechna, Janusz; Sun, Guangwei; Parraga, Pablo-Francisco

    2018-01-02

    A wave disc engine apparatus is provided. A further aspect employs a constricted nozzle in a wave rotor channel. A further aspect provides a sharp bend between an inlet and an outlet in a fluid pathway of a wave rotor, with the bend being spaced away from a peripheral edge of the wave rotor. A radial wave rotor for generating electricity in an automotive vehicle is disclosed in yet another aspect.

  10. Advanced Math: Closing the Equity Gap. Math Works

    Science.gov (United States)

    Achieve, Inc., 2013

    2013-01-01

    Minority and low-income students are less likely to have access to, enroll in and succeed in higher-level math courses in high school than their more advantaged peers. Under these circumstances, higher-level math courses function not as the intellectual and practical boost they should be, but as a filter that screens students out of the pathway to…

  11. Early Math Interest and the Development of Math Skills

    Science.gov (United States)

    Fisher, Paige H.; Dobbs-Oates, Jennifer; Doctoroff, Greta L.; Arnold, David H.

    2012-01-01

    Prior models suggest that math attitudes and ability might strengthen each other over time in a reciprocal fashion (Ma, 1997). The current study investigated the relationship between math interest and skill both concurrently and over time in a preschool sample. Analyses of concurrent relationships indicated that high levels of interest were…

  12. Math Anxiety and Math Ability in Early Primary School Years

    Science.gov (United States)

    Krinzinger, Helga; Kaufmann, Liane; Willmes, Klaus

    2009-01-01

    Mathematical learning disabilities (MLDs) are often associated with math anxiety, yet until now, very little is known about the causal relations between calculation ability and math anxiety during early primary school years. The main aim of this study was to longitudinally investigate the relationship between calculation ability, self-reported…

  13. Accretion discs around neutron stars

    International Nuclear Information System (INIS)

    Pringle, J.E.

    1982-01-01

    If the central object in the disc is a neutron star, then we do not need the disc itself to produce the X-rays. In other words, the disc structure itself is not important as long as it plays the role of depositing matter on the neutron star at a sufficient rate to produce the X-ray flux. Similarly, in the outer disc regions, the main disc luminosity comes from absorption and reradiation of X-ray photons and not from the intrinsic, viscously-produced, local energy production rate. These two points indicate why in the compact binary X-ray sources confrontation between disc theory and observations is not generally practicable. For this reason I will divide my talk into two parts: one on observational discs in which I discuss what observational evidence there is for discs in the compact X-ray sources and what the evidence can tell the theorist about disc behaviour, and the other on theoretical discs where I consider in what ways theoretical arguments can put limits or cast doubt on some of the empirical models put forward to explain the observations. (orig.)

  14. Math primer for engineers

    CERN Document Server

    Cryer, CW

    2014-01-01

    Mathematics and engineering are inevitably interrelated, and this interaction will steadily increase as the use of mathematical modelling grows. Although mathematicians and engineers often misunderstand one another, their basic approach is quite similar, as is the historical development of their respective disciplines. The purpose of this Math Primer is to provide a brief introduction to those parts of mathematics which are, or could be, useful in engineering, especially bioengineering. The aim is to summarize the ideas covered in each subject area without going into exhaustive detail. Formula

  15. Math Education at a Crossroads

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    With an enrollment of 550 students once a year the first year course Math1 at the Technical University of Denmark is one of the largest courses at university level in Denmark. Since its re-formation 6 years ago a number of interesting valuable assets concerning undergraduate math education...

  16. Math Learning Begins at Home

    Science.gov (United States)

    Eason, Sarah H.; Levine, Susan C.

    2017-01-01

    Children demonstrate gaps in the math knowledge that they possess by the time they begin school, and these gaps have been found to predict long-term outcomes not only in math but also in reading. Consequently, it is important to identify what accounts for these early differences and how they can be addressed to ensure that all children enter…

  17. From Mxit to Dr Math

    CSIR Research Space (South Africa)

    Botha, Adèle

    2013-02-01

    Full Text Available In 2007, Laurie Butgereit, a researcher at the CSIR Meraka Institute, started to use Mxit as a communication channel to tutor her son in mathematics. Her son and a number of his friends logged in, and Dr Math was born. At the inception of Dr Math...

  18. What Math Teachers Need Most

    Science.gov (United States)

    Nelson, Barbara Scott; Sassi, Annette

    2007-01-01

    The combination of new instructional methods and new accountability pressures puts many in a quandary in evaluating math instruction. There is much for principals to learn about how and under what conditions new instructional methods work in math classrooms, how to support teachers as they develop new instructional skills, and how to integrate a…

  19. "Math Anxiety" Explored in Studies

    Science.gov (United States)

    Sparks, Sarah D.

    2011-01-01

    Math problems make more than a few students--and even teachers--sweat, but new brain research is providing insights into the earliest causes of the anxiety so often associated with mathematics. Experts argue that "math anxiety" can bring about widespread, intergenerational discomfort with the subject, which could lead to anything from fewer…

  20. Math Fact Strategies Research Project

    Science.gov (United States)

    Boso, Annie

    2011-01-01

    An action research project was conducted in order to determine effective math fact strategies for first graders. The traditional way of teaching math facts included using timed tests and flashcards, with most students counting on their fingers or a number line. Six new research-based strategies were taught and analyzed to decide which methods…

  1. The math excellence workshop

    International Nuclear Information System (INIS)

    Lasser, Susan J.S.; Snelsire, Robert W.

    1992-01-01

    This paper describes the first two years of the Clemson University College of Engineering's Math Excellence Workshop, a program administered by Westinghouse Electric Corporation, Savannah River Site, and funded by the Department of Energy. The objective of the program is to prepare minority students for technical/scientific study, with the goal of increasing minority retention in the College of Engineering, Twenty-three African American students, all of whom had been accepted into the College of Engineering Fall 1990 freshman class, took part in the first year of the program. The contract paid for room, board, tuition, fees, books, and supplies for the students to live on campus and take a precalculus math course. In addition, the students attended a special honors workshop designed to prepare them to study technical material effectively. Twenty of the 23 students earned As or Bs in the precalculus class. All participants indicated that they felt confident of their ability to succeed academically at Clemson. At the end of the session, twenty of the students were still planning to major in engineering. The program was repeated the following summer with 24 students from the 1991 freshman class. Twelve of the students earned A's or B's in the precalculus class. (author)

  2. The math excellence workshop

    Energy Technology Data Exchange (ETDEWEB)

    Lasser, Susan J.S.; Snelsire, Robert W [College of Engineering, Clemson University, Clemson, SC (United States)

    1992-07-01

    This paper describes the first two years of the Clemson University College of Engineering's Math Excellence Workshop, a program administered by Westinghouse Electric Corporation, Savannah River Site, and funded by the Department of Energy. The objective of the program is to prepare minority students for technical/scientific study, with the goal of increasing minority retention in the College of Engineering, Twenty-three African American students, all of whom had been accepted into the College of Engineering Fall 1990 freshman class, took part in the first year of the program. The contract paid for room, board, tuition, fees, books, and supplies for the students to live on campus and take a precalculus math course. In addition, the students attended a special honors workshop designed to prepare them to study technical material effectively. Twenty of the 23 students earned As or Bs in the precalculus class. All participants indicated that they felt confident of their ability to succeed academically at Clemson. At the end of the session, twenty of the students were still planning to major in engineering. The program was repeated the following summer with 24 students from the 1991 freshman class. Twelve of the students earned A's or B's in the precalculus class. (author)

  3. CT discography for cervical soft disc hernia

    Energy Technology Data Exchange (ETDEWEB)

    Iwasa, Kenichi; Mizutani, Shigeru; Morimoto, Hiroyuki; Yamada, Hidehito; Iwasa, Satoru

    1985-03-01

    In this study the effectiveness of computed tomographic discography (CTD) in diagnosing cervical soft disc hernia was evaluated. Twenty-five intervertebral discs of 15 cases with cervical soft disc hernia were examined with a discography and then a CT scan. Results of the CT scan were as follows: three discs were protruded, 12 discs were prolapsed, 6 discs were extruded, and 4 discs were sequestrated. The findings were helpful in determining the location of soft disc hernias between the median and posterolateral discs. They were also valuable in classifying types of hernias and surgical approaches.

  4. CT discography for cervical soft disc hernia

    International Nuclear Information System (INIS)

    Iwasa, Kenichi; Mizutani, Shigeru; Morimoto, Hiroyuki; Yamada, Hidehito; Iwasa, Satoru

    1985-01-01

    In this study the effectiveness of computed tomographic discography (CTD) in diagnosing cervical soft disc hernia was evaluated. Twenty-five interververtebral discs of 15 cases with cervical soft disc hernia were examined with a discography and then a CT scan. Results of the CT scan were as follows: three discs were protruded, 12 discs were prolapsed, 6 discs were extruded, and 4 discs were sequestrated. The findings were helpful in determining the location of soft disc hernians between the median and posterolateral discs. They were also valuable in classifying types of hernians and surgical aproaches. (author)

  5. The Role of Parental Math Anxiety and Math Attitude in Their Children's Math Achievement

    Science.gov (United States)

    Soni, Akanksha; Kumari, Santha

    2017-01-01

    The present study investigated the antecedents and consequences of children's math anxiety and math attitude. A total of 595 students aged 10 to 15 years (5th to 10th grades) and 1 parent of each (mother or father) participated in the study. The study was conducted in India, with the study sample drawn from schools in South-West Punjab. Math…

  6. Math anxiety and math performance in children: The mediating roles of working memory and math self-concept.

    Science.gov (United States)

    Justicia-Galiano, M José; Martín-Puga, M Eva; Linares, Rocío; Pelegrina, Santiago

    2017-12-01

    Numerous studies, most of them involving adolescents and adults, have evidenced a moderate negative relationship between math anxiety and math performance. There are, however, a limited number of studies that have addressed the mechanisms underlying this relation. This study aimed to investigate the role of two possible mediational mechanisms between math anxiety and math performance. Specifically, we sought to test the simultaneous mediating role of working memory and math self-concept. A total of 167 children aged 8-12 years participated in this study. Children completed a set of questionnaires used to assess math and trait anxiety, math self-concept as well as measures of math fluency and math problem-solving. Teachers were asked to rate each student's math achievement. As measures of working memory, two backward span tasks were administered to the children. A series of multiple mediation analyses were conducted. Results indicated that both mediators (working memory and math self-concept) contributed to explaining the relationship between math anxiety and math achievement. Results suggest that working memory and self-concept could be worth considering when designing interventions aimed at helping students with math anxiety. Longitudinal designs could also be used to better understand the mediational mechanisms that may explain the relationship between math anxiety and math performance. © 2017 The British Psychological Society.

  7. Addressing Math Anxiety in the Classroom

    Science.gov (United States)

    Finlayson, Maureen

    2014-01-01

    In today's educational systems, students of all levels of education experience math anxiety. Furthermore, math anxiety is frequently linked to poor achievement in mathematics. The purpose of this study is to examine the causes of math anxiety and to explore strategies which pre-service teachers have identified to overcome math anxiety. The…

  8. Enhancing Mathematical Communication for Virtual Math Teams

    Science.gov (United States)

    Stahl, Gerry; Çakir, Murat Perit; Weimar, Stephen; Weusijana, Baba Kofi; Ou, Jimmy Xiantong

    2010-01-01

    The Math Forum is an online resource center for pre-algebra, algebra, geometry and pre-calculus. Its Virtual Math Teams (VMT) service provides an integrated web-based environment for small teams of people to discuss math and to work collaboratively on math problems or explore interesting mathematical micro-worlds together. The VMT Project studies…

  9. Helping Students Get Past Math Anxiety

    Science.gov (United States)

    Scarpello, Gary

    2007-01-01

    Math anxiety can begin as early as the fourth grade and peaks in middle school and high school. It can be caused by past classroom experiences, parental influences, and remembering poor past math performance. Math anxiety can cause students to avoid challenging math courses and may limit their career choices. It is important for teachers, parents…

  10. Gravitating discs around black holes

    International Nuclear Information System (INIS)

    Karas, V; Hure, J-M; Semerak, O

    2004-01-01

    Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole-disc system using analytical solutions of stationary, axially symmetric Einstein equations. Then, more detailed considerations are focused to the middle and outer parts of extended disc-like configurations where relativistic effects are small and the Newtonian description is adequate. Within general relativity, only a static case has been analysed in detail. Results are often very inspiring. However, simplifying assumptions must be imposed: ad hoc profiles of the disc density are commonly assumed and the effects of frame-dragging are completely lacking. Astrophysical discs (e.g. accretion discs in active galactic nuclei) typically extend far beyond the relativistic domain and are fairly diluted. However, self-gravity is still essential for their structure and evolution, as well as for their radiation emission and the impact on the surrounding environment. For example, a nuclear star cluster in a galactic centre may bear various imprints of mutual star-disc interactions, which can be recognized in observational properties, such as the relation between the central mass and stellar velocity dispersion. (topical review)

  11. String-Math 2015

    CERN Document Server

    2015-01-01

    Welcome to String-Math 2015 at Sanya. The conference will be opened in December 31, 2015- January 4, 2016. String theory plays a central role in theoretical physics as a candidate for the quantum theory unifying gravity with other interactions. It has profound connections with broad branches of modern mathematics ever since the birth. In the last decades, the prosperous interaction, built upon the joint efforts from both mathematicians and physicists, has given rise to marvelous deep results in supersymmetric gauge theory, topological string, M-theory and duality on the physics side as well as in algebraic geometry, differential geometry, algebraic topology, representation theory and number theory on the mathematics side. The interplay is two-fold. The mathematics has provided powerful tools to fulfill the physical interconnection of ideas and clarify physical structures to understand the nature of string theory. On the other hand, ideas from string theory and quantum field theory have been a source of sign...

  12. Mathe Kompakt fur Dummies

    CERN Document Server

    Zegarelli, Mark

    2015-01-01

    Der schnelle Überblick für Schüler und jeden, den es sonst noch interessiert Müssen Sie sich in der Schule oder im Beruf mit Mathematik beschäftigen und es hapert schon an den Grundlagen? Frei nach dem Motto »Einst gelernt, doch längst vergessen« bereiten oft gerade die einfachen Fragestellungen Probleme. Wie viel Prozent sind das nochmal? Wie war das doch gleich mit der Bruchrechnung und wie berechnet man eigentlich den Flächeninhalt eines Dreiecks? Keine Sorge, Mark Zegarelli erklärt es Ihnen einfach, aber zugleich amüsant, und hilft Ihnen so, Ihre Wissenslücken zu schließen. Damit ist Mathe

  13. Report on results of the Experts from the Boris Kidric Institute to the Institute for theoretical and experimental physics in Moscow - Operational Report; Radni izvestaj - Izvestaj o rezultatima posete strucnjaka iz IBK Institutu za teorijsku i eksperimentalnu fiziku u Moskvi

    Energy Technology Data Exchange (ETDEWEB)

    Martinc, R; Petrovic, M; Cupac, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1976-12-15

    Three experts from the Boris Kidric Institute of Nuclear sciences have visited the the Institute of theoretical and experimental physics in Moscow from 17-23 October 1976. The objective of this visit was to: a) obtain information about operational characteristics of the TVRS reactor with 80% enriched fuel, and experiences about utilization of this fuel in the TVRS in Moscow; b) getting acquainted with the elements of safety analysis related to conversion of TVRS reactor core to new fuel into and its utilization; and c) exchange of opinion about the program for introducing the new 80% enriched fuel into the RA reactor core. This report contains the results achieved during the visit. The most important conclusions drawn are as follows. a) The visit was successful although answers to some important questions were not obtained. b) After analyzing the obtained information and after obtaining the first experiences related to application of the new fuel in the RA reactor core and final decision about the operation equilibrium cycle with the new fuel, another visit to Moscow would be very useful. c.) New dispersion highly enriched fuel is much more reliable during operation than the 2% enriched metal uranium fuel (presently used in the Ra reactor). d) There have been no objection concerning our program for conversion of RA reactor to operation with the new fuel (transition regime). e) additional information will be demanded concerning maximum permissible burnup level of the 80% enriched dispersion fuel. Optimum equilibrium burnup cycle will be revised according to the maximum burnup conditioned by RA reactor parameters. f) Methods for thermal analysis of the fuel elements which is applied at the RA reactor was found to be equivalent with the method applied for calculations at the TVRS in Moscow. [Serbo-Croat] Grupa od tri saradnika IBK boravila je u Institutu za teorijsku i eksperimentalnu fiziku u Moskvi u vremenu od 17.10. do 23.10.1976. godine. Cilj posete je bio: a

  14. The relation between math self-concept, test and math anxiety, achievement motivation and math achievement in 12 to 14-year-old typically developing adolescents

    OpenAIRE

    Timmerman, H.L.; Toll, S.W.M.; van Luit, J.E.H.

    2017-01-01

    :This study examines the relation between math self-concept, test and math anxiety, achievement motivation, and math achievement in typically developing 12 to 14-year-old adolescents (N = 108) from a school for secondary education in the Netherlands. Data was obtained using a math speed test, achievement motivation test, and the math experience questionnaire. A significant positive correlation was found between math self-concept and math achievement in all four math domains (measurement, rela...

  15. Students as Math Level Designers

    DEFF Research Database (Denmark)

    Jensen, Erik Ottar; Hanghøj, Thorkild; Schoenau-Fog, Henrik

    The short paper presents preliminary findings from a pilot study on how students become motivated through design of learning games in math. The research is carried out in a Danish public school with two classes of 5th graders (N = 42 students). Over the course of two weeks, the students work...... with a design template for a runner game in the Unity 3D game design engine. The students are introduced to the concept of “flow” (Csikszentmihalyi, 1991) as a game design principle and are asked to design levels for a math runner game, which are both engaging as well as a meaningful way of learning math....... In this way, the students are positioned as “math level designers”, which means that they both have to redesign the difficulty of the runner game as well as the difficulty of the mathematical questions and possible answers....

  16. Parents' Beliefs about Children's Math Development and Children's Participation in Math Activities

    OpenAIRE

    Susan Sonnenschein; Claudia Galindo; Shari R. Metzger; Joy A. Thompson; Hui Chih Huang; Heather Lewis

    2012-01-01

    This study explored associations between parents’ beliefs about children’s development and children’s reported math activities at home. Seventy-three parents were interviewed about the frequency of their children’s participation in a broad array of math activities, the importance of children doing math activities at home, how children learn math, parents’ role in their children’s math learning, and parents’ own math skills. Although the sample consisted of African Americans, Chinese, Latino, ...

  17. Math Anxiety Is Related to Some, but Not All, Experiences with Math

    OpenAIRE

    Krystle O'Leary; Cheryll L. Fitzpatrick; Darcy Hallett

    2017-01-01

    Math anxiety has been defined as unpleasant feelings of tension and anxiety that hinder the ability to deal with numbers and math in a variety of situations. Although many studies have looked at situational and demographic factors associated with math anxiety, little research has looked at the self-reported experiences with math that are associated with math anxiety. The present study used a mixed-methods design and surveyed 131 undergraduate students about their experiences with math through...

  18. Universals and Specifics of Math Self-Concept, Math Self-Efficacy, and Math Anxiety across 41 PISA 2003 Participating Countries

    Science.gov (United States)

    Lee, Jihyun

    2009-01-01

    The overarching goal of the present study is to investigate the factorial structure of three closely related constructs: math self-concept, math self-efficacy, and math anxiety. The factorial structure consisting of three factors, each representing math self-concept, math self-efficacy, and math anxiety, is supported in all 41 countries employed…

  19. Attentional bias in math anxiety.

    Science.gov (United States)

    Rubinsten, Orly; Eidlin, Hili; Wohl, Hadas; Akibli, Orly

    2015-01-01

    Cognitive theory from the field of general anxiety suggests that the tendency to display attentional bias toward negative information results in anxiety. Accordingly, the current study aims to investigate whether attentional bias is involved in math anxiety (MA) as well (i.e., a persistent negative reaction to math). Twenty seven participants (14 with high levels of MA and 13 with low levels of MA) were presented with a novel computerized numerical version of the well established dot probe task. One of six types of prime stimuli, either math related or typically neutral, was presented on one side of a computer screen. The prime was preceded by a probe (either one or two asterisks) that appeared in either the prime or the opposite location. Participants had to discriminate probe identity (one or two asterisks). Math anxious individuals reacted faster when the probe was at the location of the numerical related stimuli. This suggests the existence of attentional bias in MA. That is, for math anxious individuals, the cognitive system selectively favored the processing of emotionally negative information (i.e., math related words). These findings suggest that attentional bias is linked to unduly intense MA symptoms.

  20. Double-disc gate valve

    International Nuclear Information System (INIS)

    Wheatley, S.J.

    1979-01-01

    The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

  1. Intergenerational Effects of Parents' Math Anxiety on Children's Math Achievement and Anxiety.

    Science.gov (United States)

    Maloney, Erin A; Ramirez, Gerardo; Gunderson, Elizabeth A; Levine, Susan C; Beilock, Sian L

    2015-09-01

    A large field study of children in first and second grade explored how parents' anxiety about math relates to their children's math achievement. The goal of the study was to better understand why some students perform worse in math than others. We tested whether parents' math anxiety predicts their children's math achievement across the school year. We found that when parents are more math anxious, their children learn significantly less math over the school year and have more math anxiety by the school year's end-but only if math-anxious parents report providing frequent help with math homework. Notably, when parents reported helping with math homework less often, children's math achievement and attitudes were not related to parents' math anxiety. Parents' math anxiety did not predict children's reading achievement, which suggests that the effects of parents' math anxiety are specific to children's math achievement. These findings provide evidence of a mechanism for intergenerational transmission of low math achievement and high math anxiety. © The Author(s) 2015.

  2. The role of self-math overlap in understanding math anxiety and the relation between math anxiety and performance

    OpenAIRE

    Necka, Elizabeth A.; Sokolowski, H. Moriah; Lyons, Ian M.

    2015-01-01

    Recent work has demonstrated that math anxiety is more than just the product of poor math skills. Psychosocial factors may play a key role in understanding what it means to be math anxious, and hence may aid in attempts to sever the link between math anxiety and poor math performance. One such factor may be the extent to which individuals integrate math into their sense of self. We adapted a well-established measure of this degree of integration (i.e., self-other overlap) to assess individual...

  3. Are galaxy discs optically thick?

    International Nuclear Information System (INIS)

    Disney, Michael; Davies, Jonathan; Phillipps, Steven

    1989-01-01

    We re-examine the classical optical evidence for the low optical depths traditionally assigned to spiral discs and argue that it is highly model-dependent and unconvincing. In particular, layered models with a physically thin but optically thick dust layer behave like optically thin discs. The opposite hypotheses, that such discs are optically thick is then examined in the light of modern evidence. We find it to be consistent with the near-infrared and IRAS observations, with the surface brightnesses, with the HI and CO column densities and with the Hα measurements. (author)

  4. Disc piezoelectric ceramic transformers.

    Science.gov (United States)

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

  5. Disc Golf: Teaching a Lifetime Activity

    Science.gov (United States)

    Eastham, Susan L.

    2015-01-01

    Disc golf is a lifetime activity that can be enjoyed by students of varying skill levels and abilities. Disc golf follows the principles of ball golf but is generally easier for students to play and enjoy success. The object of disc golf is similar to ball golf and involves throwing a disc from the teeing area to the target in as few throws as…

  6. When approximate number acuity predicts math performance: The moderating role of math anxiety

    Science.gov (United States)

    Libertus, Melissa E.

    2018-01-01

    Separate lines of research suggest that people who are better at estimating numerical quantities using the approximate number system (ANS) have better math performance, and that people with high levels of math anxiety have worse math performance. Only a handful of studies have examined both ANS acuity and math anxiety in the same participants and those studies report contradictory results. To address these inconsistencies, in the current study 87 undergraduate students completed assessments of ANS acuity, math anxiety, and three different measures of math. We considered moderation models to examine the interplay of ANS acuity and math anxiety on different aspects of math performance. Math anxiety and ANS acuity were both unique significant predictors of the ability to automatically recall basic number facts. ANS acuity was also a unique significant predictor of the ability to solve applied math problems, and this relation was further qualified by a significant interaction with math anxiety: the positive association between ANS acuity and applied problem solving was only present in students with high math anxiety. Our findings suggest that ANS acuity and math anxiety are differentially related to various aspects of math and should be considered together when examining their respective influences on math ability. Our findings also raise the possibility that good ANS acuity serves as a protective factor for highly math-anxious students on certain types of math assessments. PMID:29718939

  7. Measurement of math beliefs and their associations with math behaviors in college students.

    Science.gov (United States)

    Hendy, Helen M; Schorschinsky, Nancy; Wade, Barbara

    2014-12-01

    Our purpose in the present study was to expand understanding of math beliefs in college students by developing 3 new psychometrically tested scales as guided by expectancy-value theory, self-efficacy theory, and health belief model. Additionally, we identified which math beliefs (and which theory) best explained variance in math behaviors and performance by college students and which students were most likely to have problematic math beliefs. Study participants included 368 college math students who completed questionnaires to report math behaviors (attending class, doing homework, reading textbooks, asking for help) and used a 5-point rating scale to indicate a variety of math beliefs. For a subset of 84 students, math professors provided final math grades. Factor analyses produced a 10-item Math Value Scale with 2 subscales (Class Devaluation, No Future Value), a 7-item single-dimension Math Confidence Scale, and an 11-item Math Barriers Scale with 2 subscales (Math Anxiety, Discouraging Words). Hierarchical multiple regression revealed that high levels of the newly discovered class devaluation belief (guided by expectancy-value theory) were most consistently associated with poor math behaviors in college students, with high math anxiety (guided by health belief model) and low math confidence (guided by self-efficacy theory) also found to be significant. Analyses of covariance revealed that younger and male students were at increased risk for class devaluation and older students were at increased risk for poor math confidence. (c) 2014 APA, all rights reserved.

  8. When approximate number acuity predicts math performance: The moderating role of math anxiety.

    Science.gov (United States)

    Braham, Emily J; Libertus, Melissa E

    2018-01-01

    Separate lines of research suggest that people who are better at estimating numerical quantities using the approximate number system (ANS) have better math performance, and that people with high levels of math anxiety have worse math performance. Only a handful of studies have examined both ANS acuity and math anxiety in the same participants and those studies report contradictory results. To address these inconsistencies, in the current study 87 undergraduate students completed assessments of ANS acuity, math anxiety, and three different measures of math. We considered moderation models to examine the interplay of ANS acuity and math anxiety on different aspects of math performance. Math anxiety and ANS acuity were both unique significant predictors of the ability to automatically recall basic number facts. ANS acuity was also a unique significant predictor of the ability to solve applied math problems, and this relation was further qualified by a significant interaction with math anxiety: the positive association between ANS acuity and applied problem solving was only present in students with high math anxiety. Our findings suggest that ANS acuity and math anxiety are differentially related to various aspects of math and should be considered together when examining their respective influences on math ability. Our findings also raise the possibility that good ANS acuity serves as a protective factor for highly math-anxious students on certain types of math assessments.

  9. When approximate number acuity predicts math performance: The moderating role of math anxiety.

    Directory of Open Access Journals (Sweden)

    Emily J Braham

    Full Text Available Separate lines of research suggest that people who are better at estimating numerical quantities using the approximate number system (ANS have better math performance, and that people with high levels of math anxiety have worse math performance. Only a handful of studies have examined both ANS acuity and math anxiety in the same participants and those studies report contradictory results. To address these inconsistencies, in the current study 87 undergraduate students completed assessments of ANS acuity, math anxiety, and three different measures of math. We considered moderation models to examine the interplay of ANS acuity and math anxiety on different aspects of math performance. Math anxiety and ANS acuity were both unique significant predictors of the ability to automatically recall basic number facts. ANS acuity was also a unique significant predictor of the ability to solve applied math problems, and this relation was further qualified by a significant interaction with math anxiety: the positive association between ANS acuity and applied problem solving was only present in students with high math anxiety. Our findings suggest that ANS acuity and math anxiety are differentially related to various aspects of math and should be considered together when examining their respective influences on math ability. Our findings also raise the possibility that good ANS acuity serves as a protective factor for highly math-anxious students on certain types of math assessments.

  10. Lumbar disc excision through fenestration

    Directory of Open Access Journals (Sweden)

    Sangwan S

    2006-01-01

    Full Text Available Background : Lumbar disc herniation often causes sciatica. Many different techniques have been advocated with the aim of least possible damage to other structures while dealing with prolapsed disc surgically in the properly selected and indicated cases. Methods : Twenty six patients with clinical symptoms and signs of prolapsed lumbar intervertebral disc having radiological correlation by MRI study were subjected to disc excision by interlaminar fenestration method. Results : The assessment at follow-up showed excellent results in 17 patients, good in 6 patients, fair in 2 patients and poor in 1 patient. The mean preoperative and postoperative Visual Analogue Scores were 9.34 ±0.84 and 2.19 ±0.84 on scale of 0-10 respectively. These were statistically significant (p value< 0.001, paired t test. No significant complications were recorded. Conclusion : Procedures of interlaminar fenestration and open disc excision under direct vision offers sufficient adequate exposure for lumbar disc excision with a smaller incision, lesser morbidity, shorter convalescence, early return to work and comparable overall results in the centers where recent laser and endoscopy facilities are not available.

  11. Comparison of Animal Discs Used in Disc Research to Human Lumbar Disc: Torsion Mechanics and Collagen Content

    Science.gov (United States)

    Showalter, Brent L.; Beckstein, Jesse C.; Martin, John T.; Beattie, Elizabeth E.; Orías, Alejandro A. Espinoza; Schaer, Thomas P.; Vresilovic, Edward J.; Elliott, Dawn M.

    2012-01-01

    Study Design Experimental measurement and normalization of in vitro disc torsion mechanics and collagen content for several animal species used in intervertebral disc research and comparing these to the human disc. Objective To aid in the selection of appropriate animal models for disc research by measuring torsional mechanical properties and collagen content. Summary of Background Data There is lack of data and variability in testing protocols for comparing animal and human disc torsion mechanics and collagen content. Methods Intervertebral disc torsion mechanics were measured and normalized by disc height and polar moment of inertia for 11 disc types in 8 mammalian species: the calf, pig, baboon, goat, sheep, rabbit, rat, and mouse lumbar, and cow, rat, and mouse caudal. Collagen content was measured and normalized by dry weight for the same discs except the rat and mouse. Collagen fiber stretch in torsion was calculated using an analytical model. Results Measured torsion parameters varied by several orders of magnitude across the different species. After geometric normalization, only the sheep and pig discs were statistically different from human. Fiber stretch was found to be highly dependent on the assumed initial fiber angle. The collagen content of the discs was similar, especially in the outer annulus where only the calf and goat discs were statistically different from human. Disc collagen content did not correlate with torsion mechanics. Conclusion Disc torsion mechanics are comparable to human lumbar discs in 9 of 11 disc types after normalization by geometry. The normalized torsion mechanics and collagen content of the multiple animal discs presented is useful for selecting and interpreting results for animal models of the disc. Structural composition of the disc, such as initial fiber angle, may explain the differences that were noted between species after geometric normalization. PMID:22333953

  12. Identifying Maths Anxiety in Student Nurses and Focusing Remedial Work

    Science.gov (United States)

    Bull, Heather

    2009-01-01

    Maths anxiety interferes with maths cognition and thereby increases the risk of maths errors. To initiate strategies for preventing anxiety-related errors progressing into nursing practice, this study explored the hypothesis that student nurses experience high maths anxiety in association with poor maths performance, and that high maths anxiety is…

  13. A Motivational Technique for Business Math

    Science.gov (United States)

    Voelker, Pamela

    1977-01-01

    The author suggests the use of simulation and role playing as a method of motivating students in business math. Examples of career-oriented business math simulation games are counting change, banking, payrolls, selling, and shopping. (MF)

  14. Math Anxiety, Working Memory, and Math Achievement in Early Elementary School

    Science.gov (United States)

    Ramirez, Gerardo; Gunderson, Elizabeth A.; Levine, Susan C.; Beilock, Sian L.

    2013-01-01

    Although math anxiety is associated with poor mathematical knowledge and low course grades (Ashcraft & Krause, 2007), research establishing a connection between math anxiety and math achievement has generally been conducted with young adults, ignoring the emergence of math anxiety in young children. In the current study, we explored whether…

  15. A Latent Profile Analysis of Math Achievement, Numerosity, and Math Anxiety in Twins

    Science.gov (United States)

    Hart, Sara A.; Logan, Jessica A. R.; Thompson, Lee; Kovas, Yulia; McLoughlin, Gráinne; Petrill, Stephen A.

    2016-01-01

    Underperformance in math is a problem with increasing prevalence, complex etiology, and severe repercussions. This study examined the etiological heterogeneity of math performance in a sample of 264 pairs of 12-year-old twins assessed on measures of math achievement, numerosity, and math anxiety. Latent profile analysis indicated 5 groupings of…

  16. Reciprocal Relations among Motivational Frameworks, Math Anxiety, and Math Achievement in Early Elementary School

    Science.gov (United States)

    Gunderson, Elizabeth A.; Park, Daeun; Maloney, Erin A.; Beilock, Sian L.; Levine, Susan C.

    2018-01-01

    School-entry math achievement is a strong predictor of math achievement through high school. We asked whether reciprocal relations among math achievement, math anxiety, and entity motivational frameworks (believing that ability is fixed and a focus on performance) can help explain these persistent individual differences. We assessed 1st and 2nd…

  17. Evolution of viscous discs. 3. Giant discs in symbiotic stars

    Energy Technology Data Exchange (ETDEWEB)

    Bath, G T [Oxford Univ. (UK). Dept. of Astrophysics; Pringle, J E [Cambridge Univ. (UK). Inst. of Astronomy

    1982-10-01

    The structure of time-dependent accretion discs in giant binaries with separation of the order of 10/sup 13/ cm is examined. Radiative ..cap alpha..-viscosity discs with ..cap alpha.. of order unity accreting on to main-sequence stars at accretion rates which generate luminosities greater than a giant companion decay on time-scales of the same order as the binary period, unlike those in dwarf nova binaries which decay on time-scales 100 times longer than the binary period. This results from the lower gravitational potential and consequent larger disc thickness (relative to the radius) of luminous 'giant' discs accreting at high accretion rates. The eruptions of the symbiotic binary C I Cygni are modelled by an ..cap alpha.. = 1 disc with outer radius 8.5 x 10/sup 12/ cm and a sequence of five mass-transfer bursts at rates between 1.5 x 10/sup 21/ and 4 x 10/sup 22/g s/sup -1/.

  18. Math word problems for dummies

    CERN Document Server

    Sterling, Mary Jane

    2008-01-01

    Covers percentages, probability, proportions, and moreGet a grip on all types of word problems by applying them to real lifeAre you mystified by math word problems? This easy-to-understand guide shows you how to conquer these tricky questions with a step-by-step plan for finding the right solution each and every time, no matter the kind or level of problem. From learning math lingo and performing operations to calculating formulas and writing equations, you''ll get all the skills you need to succeed!Discover how to: * Translate word problems into plain English* Brush up on basic math skills* Plug in the right operation or formula* Tackle algebraic and geometric problems* Check your answers to see if they work

  19. Response to intervention in math

    CERN Document Server

    Riccomini, Paul J

    2010-01-01

    Boost academic achievement for all students in your mathematics classroom! This timely resource leads the way in applying RTI to mathematics instruction. The authors describe how the three tiers can be implemented in specific math areas and illustrate RTI procedures through case studies. Aligned with the NMAP final report and IES practice guide, this book includes: Intervention strategies for number sense, fractions, problem solving, and more Procedures for teaching math using systematic and explicit instruction for assessment, instructional planning, and evaluation Essential components to con

  20. The Effects of the Elevate Math Summer Program on Math Achievement and Algebra Readiness. REL 2015-096

    Science.gov (United States)

    Snipes, Jason; Huang, Chun-Wei; Jaquet, Karina; Finkelstein, Neal

    2015-01-01

    The Effects of the Elevate Math summer program on math achievement and algebra readiness: This randomized trial examined the effects of the Elevate Math summer program on math achievement and algebra readiness, as well as math interest and self-efficacy, among rising 8th grade students in California's Silicon Valley. The Elevate Math summer math…

  1. Math Branding in a Community College Library

    Science.gov (United States)

    Brantz, Malcolm; Sadowski, Edward B.

    2010-01-01

    As a strategy to promote the Arapahoe Community College Library's collections and services, the Library undertook to brand itself as a math resource center. In promoting one area of expertise, math was selected to help address the problem of a large portion of high school graduates' inability to work at college-level math. A "Math…

  2. Saxon Math. What Works Clearinghouse Intervention Report

    Science.gov (United States)

    What Works Clearinghouse, 2017

    2017-01-01

    "Saxon Math" is a curriculum for students in grades K-12. The amount of new math content students receive each day is limited and students practice concepts every day. New concepts are developed, reviewed, and practiced cumulatively rather than in discrete chapters or units. This review focuses on studies of "Saxon Math"'s…

  3. Math Game(s) - an alternative (approach) to teaching math?

    NARCIS (Netherlands)

    Ruttkay, Z.M.; Eliens, A.P.W.; Breitlauch, L.

    2009-01-01

    Getting students to read, digest and practice material is difficult in any discipline, but even more so for math, since many students have to cope with motivational problems and feelings of inadequacy, often due to prior unsuccesful training and teaching methods. In this paper we look at the

  4. Taking Math Outside of the Classroom: Math in the City

    Science.gov (United States)

    Radu, Petronela

    2013-01-01

    Math in the City is an interdisciplinary mathematics course offered at University of Nebraska-Lincoln in which students engage in a real-world experience to understand current major societal issues of local and national interest. The course is run in collaboration with local businesses, research centers, and government organizations, that provide…

  5. Americans Need Advanced Math to Stay Globally Competitive. Math Works

    Science.gov (United States)

    Achieve, Inc., 2013

    2013-01-01

    No student who hopes to compete in today's rapidly evolving global economy and job market can afford to graduate from high school with weak mathematical skills, which include the ability to use logic, reason, and solve problems. The benefits associated with improving the math performance of American students also extend to the larger U.S. economy.…

  6. Understanding the Home Math Environment and Its Role in Predicting Parent Report of Children's Math Skills.

    Science.gov (United States)

    Hart, Sara A; Ganley, Colleen M; Purpura, David J

    2016-01-01

    There is a growing literature concerning the role of the home math environment in children's math development. In this study, we examined the relation between these constructs by specifically addressing three goals. The first goal was to identify the measurement structure of the home math environment through a series of confirmatory factor analyses. The second goal was to examine the role of the home math environment in predicting parent report of children's math skills. The third goal was to test a series of potential alternative explanations for the relation between the home math environment and parent report of children's skills, specifically the direct and indirect role of household income, parent math anxiety, and parent math ability as measured by their approximate number system performance. A final sample of 339 parents of children aged 3 through 8 drawn from Mechanical Turk answered a questionnaire online. The best fitting model of the home math environment was a bifactor model with a general factor representing the general home math environment, and three specific factors representing the direct numeracy environment, the indirect numeracy environment, and the spatial environment. When examining the association of the home math environment factors to parent report of child skills, the general home math environment factor and the spatial environment were the only significant predictors. Parents who reported doing more general math activities in the home reported having children with higher math skills, whereas parents who reported doing more spatial activities reported having children with lower math skills.

  7. Is Mathematical Anxiety Always Bad for Math Learning: The Role of Math Motivation

    Science.gov (United States)

    Wang, Zhe; Lukowski, Sarah L.; Hart, Sara Ann; Lyons, Ian M.; Thompson, Lee A.; Kovas, Yulia; Mazzocco, Michèle M.; Plomin, Robert; Petrill, Stephen A.

    2015-01-01

    The linear relations between math anxiety and math cognition have been frequently studied. However, the relations between anxiety and performance on complex cognitive tasks have been repeatedly demonstrated to follow a curvilinear fashion. Given the lack of attention to the possibility of such complex interplay between emotion and cognition in the math learning literature, the current study aimed to address this gap via exploring the relations between math anxiety, math motivation, and math cognition. The current study consisted of two samples. One sample included 262 pairs of young adolescent twins and the other included 237 adult college students. Participants self-reported their math anxiety and math motivation. Math cognition was assessed using a comprehensive battery of mathematics tasks. In both samples, results showed inverted-U relations between math anxiety and math performance in students with high intrinsic math motivation, and modest negative associations between math anxiety and math performance in students with low intrinsic math motivation. However, this pattern was not observed in tasks assessing student’s nonsymbolic and symbolic number estimation. These findings may help advance our understanding of mathematics learning processes and may provide important insights for treatment programs that target improving mathematics learning experiences and mathematical skills. PMID:26518438

  8. Understanding the Home Math Environment and Its Role in Predicting Parent Report of Children's Math Skills.

    Directory of Open Access Journals (Sweden)

    Sara A Hart

    Full Text Available There is a growing literature concerning the role of the home math environment in children's math development. In this study, we examined the relation between these constructs by specifically addressing three goals. The first goal was to identify the measurement structure of the home math environment through a series of confirmatory factor analyses. The second goal was to examine the role of the home math environment in predicting parent report of children's math skills. The third goal was to test a series of potential alternative explanations for the relation between the home math environment and parent report of children's skills, specifically the direct and indirect role of household income, parent math anxiety, and parent math ability as measured by their approximate number system performance. A final sample of 339 parents of children aged 3 through 8 drawn from Mechanical Turk answered a questionnaire online. The best fitting model of the home math environment was a bifactor model with a general factor representing the general home math environment, and three specific factors representing the direct numeracy environment, the indirect numeracy environment, and the spatial environment. When examining the association of the home math environment factors to parent report of child skills, the general home math environment factor and the spatial environment were the only significant predictors. Parents who reported doing more general math activities in the home reported having children with higher math skills, whereas parents who reported doing more spatial activities reported having children with lower math skills.

  9. All you need in Maths!

    NARCIS (Netherlands)

    van de Craats, J.; Bosch, R.

    2014-01-01

    All You Need in Maths! covers the basic mathematics you need to successfully embark on a university or college career in technology, natural sciences, computer and information science, economics, business and management studies, and related disciplines. By basic mathematics we mean elementary

  10. Meeting a Math Achievement Crisis

    Science.gov (United States)

    Jennings, Lenora; Likis, Lori

    2005-01-01

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

  11. Teaching Math to the Talented

    Science.gov (United States)

    Hanushek, Eric A.; Peterson, Paul E.; Woessmann, Ludger

    2011-01-01

    Maintaining America's productivity as a nation depends importantly on developing a highly qualified cadre of scientists, engineers, entrepreneurs, and other professionals. To realize that objective requires a system of schooling that produces students with advanced math and science skills. To see how well schools in the United States do at…

  12. Big Math for Little Kids

    Science.gov (United States)

    Greenes, Carole; Ginsburg, Herbert P.; Balfanz, Robert

    2004-01-01

    "Big Math for Little Kids," a comprehensive program for 4- and 5-year-olds, develops and expands on the mathematics that children know and are capable of doing. The program uses activities and stories to develop ideas about number, shape, pattern, logical reasoning, measurement, operations on numbers, and space. The activities introduce the…

  13. Basic Maths Practice Problems For Dummies

    CERN Document Server

    Beveridge, Colin

    2012-01-01

    Fun, friendly coaching and all the practice you need to tackle maths problems with confidence and ease In his popular Basic Maths For Dummies, professional maths tutor Colin Beveridge proved that he could turn anyone - even the most maths-phobic person - into a natural-born number cruncher. In this book he supplies more of his unique brand of maths-made- easy coaching, plus 2,000 practice problems to help you master what you learn. Whether you're prepping for a numeracy test or an employability exam, thinking of returning to school, or you'd just like to be one of those know-it-alls who says

  14. Vertebral osteomyelitis without disc involvement

    Energy Technology Data Exchange (ETDEWEB)

    Kamani, I.; Syed, I.; Saifuddin, A. E-mail: asaifuddin@aol.com; Green, R.; MacSweeney, F

    2004-10-01

    Vertebral osteomyelitis is most commonly due to pyogenic or granulomatous infection and typically results in the combined involvement of the intervertebral disc and adjacent vertebral bodies. Non-infective causes include the related conditions of chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. Occasionally, these conditions may present purely within the vertebral body, resulting in various combinations of vertebral marrow oedema and sclerosis, destructive lesions of the vertebral body and pathological vertebral collapse, thus mimicking neoplastic disease. This review illustrates the imaging features of vertebral osteomyelitis without disc involvement, with emphasis on magnetic resonance imaging (MRI) findings.

  15. Three brief assessments of math achievement.

    Science.gov (United States)

    Steiner, Eric T; Ashcraft, Mark H

    2012-12-01

    Because of wide disparities in college students' math knowledge-that is, their math achievement-studies of cognitive processing in math tasks also need to assess their individual level of math achievement. For many research settings, however, using existing math achievement tests is either too costly or too time consuming. To solve this dilemma, we present three brief tests of math achievement here, two drawn from the Wide Range Achievement Test and one composed of noncopyrighted items. All three correlated substantially with the full achievement test and with math anxiety, our original focus, and all show acceptable to excellent reliability. When lengthy testing is not feasible, one of these brief tests can be substituted.

  16. Affective and Motivational Factors Mediate the Relation between Math Skills and Use of Math in Everyday Life

    Science.gov (United States)

    Jansen, Brenda R. J.; Schmitz, Eva A.; van der Maas, Han L. J.

    2016-01-01

    This study focused on the use of math in everyday life (the propensity to recognize and solve quantitative issues in real life situations). Data from a Dutch nation-wide research on math among adults (N = 521) were used to investigate the question whether math anxiety and perceived math competence mediated the relationship between math skills and use of math in everyday life, taken gender differences into account. Results showed that women reported higher math anxiety, lower perceived math competence, and lower use of math in everyday life, compared to men. Women's skills were estimated at a lower level than men's. For both women and men, higher skills were associated with higher perceived math competence, which in turn was associated with more use of math in everyday life. Only for women, math anxiety also mediated the relation between math skills and use of math in everyday life. PMID:27148122

  17. Affective and motivational factors mediate the relation between math skills and use of math in everyday life

    Directory of Open Access Journals (Sweden)

    Brenda RJ Jansen

    2016-04-01

    Full Text Available This study focused on the use of math in everyday life (the propensity to recognize and solve quantitative issues in real life situations. Data from a Dutch nation-wide research on math among adults (N = 521 were used to investigate the question whether math anxiety and perceived math competence mediated the relationship between math skills and use of math in everyday life, taken gender differences into account. Results showed that women reported higher math anxiety, lower perceived math competence, and lower use of math in everyday life, compared to men. Women's skills were estimated at a lower level than men's. For both women and men, higher skills were associated with higher perceived math competence, which in turn was associated with more use of math in everyday life. Only for women, math anxiety also mediated the relation between math skills and use of math in everyday life.

  18. Intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bergknut, N.

    2011-01-01

    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  19. Intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bergknut, Niklas

    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  20. CT morphometry of adult thoracic intervertebral discs.

    Science.gov (United States)

    Fletcher, Justin G R; Stringer, Mark D; Briggs, Christopher A; Davies, Tilman M; Woodley, Stephanie J

    2015-10-01

    Despite being commonly affected by degenerative disorders, there are few data on normal thoracic intervertebral disc dimensions. A morphometric analysis of adult thoracic intervertebral discs was, therefore, undertaken. Archival computed tomography scans of 128 recently deceased individuals (70 males, 58 females, 20-79 years) with no known spinal pathology were analysed to determine thoracic disc morphometry and variations with disc level, sex and age. Reliability was assessed by intraclass correlation coefficients (ICCs). Anterior and posterior intervertebral disc heights and axial dimensions were significantly greater in men (anterior disc height 4.0±1.4 vs 3.6±1.3 mm; posterior disc height 3.6±0.90 vs 3.4±0.93 mm; p<0.01). Disc heights and axial dimensions at T4-5 were similar or smaller than at T2-3, but thereafter increased caudally (mean anterior disc height T4-5 and T10-11, 2.7±0.7 and 5.4±1.2 mm, respectively, in men; 2.6±0.8 and 5.1±1.3 mm, respectively, in women; p<0.05). Except at T2-3, anterior disc height decreased with advancing age and anteroposterior and transverse disc dimensions increased; posterior and middle disc heights and indices of disc shape showed no consistent statistically significant changes. Most parameters showed substantial to almost perfect agreement for intra- and inter-rater reliability. Thoracic disc morphometry varies significantly and consistently with disc level, sex and age. This study provides unique reference data on adult thoracic intervertebral disc morphometry, which may be useful when interpreting pathological changes and for future biomechanical and functional studies.

  1. Strengthening maths learning dispositions through ‘math clubs’

    OpenAIRE

    Mellony Graven

    2016-01-01

    In this paper, I argue that the establishment of after-school mathematics clubs in early grades holds rich potential for supporting the development of increasingly participatory and sense-making maths learning dispositions. Within the South African Numeracy Chair project, lead by the author, multiple after-school mathematics clubs have been set up for learners in Grades 3-6 across Eastern Cape schools. These clubs are a complementary initiative to teacher development, aimed at improving low l...

  2. Math Game(s) - an alternative (approach) to teaching math?

    OpenAIRE

    Ruttkay, Z.M.; Eliens, A.P.W.; Breitlauch, L.

    2009-01-01

    Getting students to read, digest and practice material is difficult in any discipline, but even more so for math, since many students have to cope with motivational problems and feelings of inadequacy, often due to prior unsuccesful training and teaching methods. In this paper we look at the opportunities offered by computer graphics, visual programming and game design as an alternative for traditional methods of teaching mathemathics. In particular, games may be deployed both as intruments to d...

  3. Thermochemical modelling of brown dwarf discs

    NARCIS (Netherlands)

    Greenwood, A. J.; Kamp, I.; Waters, L. B. F. M.; Woitke, P.; Thi, W.-F.; Rab, Ch.; Aresu, G.; Spaans, M.

    The physical properties of brown dwarf discs, in terms of their shapes and sizes, are still largely unexplored by observations. ALMA has by far the best capabilities to observe these discs in sub-mm CO lines and dust continuum, while also spatially resolving some discs. To what extent brown dwarf

  4. Disc degeneration: current surgical options

    Directory of Open Access Journals (Sweden)

    C Schizas

    2010-10-01

    Full Text Available Chronic low back pain attributed to lumbar disc degeneration poses a serious challenge to physicians. Surgery may be indicated in selected cases following failure of appropriate conservative treatment. For decades, the only surgical option has been spinal fusion, but its results have been inconsistent. Some prospective trials show superiority over usual conservative measures while others fail to demonstrate its advantages. In an effort to improve results of fusion and to decrease the incidence of adjacent segment degeneration, total disc replacement techniques have been introduced and studied extensively. Short-term results have shown superiority over some fusion techniques. Mid-term results however tend to show that this approach yields results equivalent to those of spinal fusion. Nucleus replacement has gained some popularity initially, but evidence on its efficacy is scarce. Dynamic stabilisation, a technique involving less rigid implants than in spinal fusion and performed without the need for bone grafting, represents another surgical option. Evidence again is lacking on its superiority over other surgical strategies and conservative measures. Insertion of interspinous devices posteriorly, aiming at redistributing loads and relieving pain, has been used as an adjunct to disc removal surgery for disc herniation. To date however, there is no clear evidence on their efficacy. Minimally invasive intradiscal thermocoagulation techniques have also been tried, but evidence of their effectiveness is questioned. Surgery using novel biological solutions may be the future of discogenic pain treatment. Collaboration between clinicians and basic scientists in this multidisciplinary field will undoubtedly shape the future of treating symptomatic disc degeneration.

  5. CT findings of lumbar intervertebral disc: II. Disc herniation (HNP)

    International Nuclear Information System (INIS)

    Yang, W. J.; Lee, J. M.; Bahk, Y. W.

    1984-01-01

    In lumbar region the epidural fat pad is relatively abundant so that CT can provides sufficient information in diagnosis of lumbar HNP. Many authors have reported on the CT findings of HNP such as focal nodular protrusion of the posterior disc margin, obliteration of epidural fat pad, impingement of dural sac and nerve root, swelling of nerve root, soft tissue density in the spinal canal and calcification of disc. However there was so previous report describing incidence and reliability of the findings. It is the purpose of the present study to survey the frequency, reliability, and limitation of these CT findings. The clinical material was consisted of 30 operatively proven cases of HNP of the lumbar spine. Each lumbar CT scan was reviewed retrospectively and the findings were analysed by two radiologists independently. There were 20 males and 10 females and the mean age was 36.7 years. Involvement of L4-S5 level was 2.3 times more frequent than that of L5-S1 level. Of 30 cases, 22 were unilateral posterolateral types and 8 cases central or unilateral far lateral types. CT findings observed were nodular protrusion of the posterior margin of the disc, obliteration of epidural fat pad, impingement of dural sac or nerve root, soft tissue density in the spinal canal and calcification in the posterior portion of the protruded disc, in order of decreasing frequency. The conclusions are follows: 1. Nodular protrusion of the posterior disc margin accompanied by obliteration of epidural fat pad was observed in every case. The former findings was designated as direct sign and the latter indirect. 2. Obliteration of the epidural fat appears to be significant in lateral recesses especially when it occurs unilaterally. This was not true, however, in the centrally located fat pad. 3. Impingement of the dural sac and nerve root were observed in 90% and 67%, respectively, and were very helpful in establishing HNP diagnosis when the direct and indirect signs were equivocal

  6. Nurses' maths: researching a practical approach.

    Science.gov (United States)

    Wilson, Ann

    To compare a new practical maths test with a written maths test. The tests were undertaken by qualified nurses training for intravenous drug administration, a skill dependent on maths accuracy. The literature showed that the higher education institutes (HEIs) that provide nurse training use traditional maths tests, a practical way of testing maths had not been described. Fifty five nurses undertook two maths tests based on intravenous drug calculations. One was a traditional written test. The second was a new type of test using a simulated clinical environment. All participants were also interviewed one week later to ascertain their thoughts and feelings about the tests. There was a significant improvement in maths test scores for those nurses who took the practical maths test first. It is suggested that this is because it improved their conceptualisation skills and thus helped them to achieve accuracy in their calculations. Written maths tests are not the best way to help and support nurses in acquiring and improving their maths skills and should be replaced by a more practical approach.

  7. Family Maths and Complexity Theory

    OpenAIRE

    Webb, Paul; Austin, Pam

    2012-01-01

    The importance of family involvement is highlighted by findings that parents’ behaviours, beliefs and attitudes affect children’s behaviour in a major way. The Family Maths programme, which is the focus of this study, provides support for the transformative education practices targeted by the South African Department of Education by offering an intervention which includes teachers, learners and their families in an affirming learning community. In this study participating parents were intervi...

  8. Greg Tang: Making Math Count

    Science.gov (United States)

    Pierpont, Katherine

    2006-01-01

    Greg Tang has a resume that could get his foot in the door to a lot of places. A graduate of Harvard with both a B.A. and M.A. in economics, Tang has found success as a business executive, a speechwriter, a software designer and owner of a Tae Kwon Do school. After the publication of his first best-selling book for children, "The Grapes of Math"…

  9. Maths4Stats: Educating teachers

    Directory of Open Access Journals (Sweden)

    Renette J. Blignaut

    2013-02-01

    Full Text Available The inadequate nature of the education infrastructure in South Africa has led to poor academic performance at public schools. Problems within schools such as under-qualified teachers and poor teacher performance arise due to the poorly constructed education system in our country. The implementation in 2012 of the Curriculum and Assessment Policy Statement (CAPS at public schools in South Africa saw the further crippling of some teachers, as they were unfamiliar with parts of the CAPS subject content. The Statistics and Population Studies department at the University of the Western Cape was asked to join the Maths4Stats project in 2012. This project was launched by Statistics South Africa in an effort to assist in training the teachers in statistical content within the CAPS Mathematics curricula. The University of the Western Cape’s team would like to share their experience of being part of the Maths4Stats training in the Western Cape. This article focuses on how the training sessions were planned and what the outcomes were. With the knowledge gained from our first Maths4Stats experience, it is recommended that future interventions are still needed to ensure that mathematics teachers become well-informed and confident to teach topics such as data handling, probability and regression analysis.

  10. Productive failure in learning math.

    Science.gov (United States)

    Kapur, Manu

    2014-06-01

    When learning a new math concept, should learners be first taught the concept and its associated procedures and then solve problems, or solve problems first even if it leads to failure and then be taught the concept and the procedures? Two randomized-controlled studies found that both methods lead to high levels of procedural knowledge. However, students who engaged in problem solving before being taught demonstrated significantly greater conceptual understanding and ability to transfer to novel problems than those who were taught first. The second study further showed that when given an opportunity to learn from the failed problem-solving attempts of their peers, students outperformed those who were taught first, but not those who engaged in problem solving first. Process findings showed that the number of student-generated solutions significantly predicted learning outcomes. These results challenge the conventional practice of direct instruction to teach new math concepts and procedures, and propose the possibility of learning from one's own failed problem-solving attempts or those of others before receiving instruction as alternatives for better math learning. © 2014 Cognitive Science Society, Inc.

  11. MR imaging findings of a sequestered disc in the lumbar spine: a comparison with an extruded disc

    International Nuclear Information System (INIS)

    Sim, Su Youn; Park, Ji Seon; Ryu, Kyung Nam; Jin, Wook

    2007-01-01

    To compare the MR findings of a sequestered disc with an extruded disc. MR images of 28 patients with a sequestered disc and 18 patients with an extruded disc were retrospectively reviewed. Patients with sequestered discs were divided into two groups whether definite separation from the parent disc was or was not seen. In the latter group (definite separation not seen) and the extruded disc group of patients, the signal intensities of the herniated discs were compared with the signal intensities of the parent discs and were evaluated on T1-and T2-weighted images. We also assessed the presence of a notch within the herniated disc. In the sequestered disc group of patients (28 discs), only 5 discs (18%) showed obvious separation from the parent disc. Among the remaining 23 discs with indefinite separation, the notch was visible in 14 discs (61%) and 9 discs (39%) had no notch. In the extruded disc group (18 discs), the notch was visible in 2 (11%) discs and the difference between the two groups was statistically significant (ρ 0.0002). The signal intensities of the herniated discs on T1-weighted images were isointense in both the sequestered and extruded discs. The difference of incidence of high signal intensities on T2-weighted images was not statistically significant (ρ = 0.125). It is necessary to consider the possibility of the presence of a sequestered disc when a herniated disc material shows a notch

  12. Retina image–based optic disc segmentation

    Directory of Open Access Journals (Sweden)

    Ching-Lin Wang

    2016-05-01

    Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

  13. Changes in Math Prerequisites and Student Performance in Business Statistics: Do Math Prerequisites Really Matter?

    OpenAIRE

    Jeffrey J. Green; Courtenay C. Stone; Abera Zegeye; Thomas A. Charles

    2007-01-01

    We use a binary probit model to assess the impact of several changes in math prerequisites on student performance in an undergraduate business statistics course. While the initial prerequisites did not necessarily provide students with the necessary math skills, our study, the first to examine the effect of math prerequisite changes, shows that these changes were deleterious to student performance. Our results helped convince the College of Business to change the math prerequisite again begin...

  14. Inhibition Performance in Children with Math Disabilities

    OpenAIRE

    Winegar, Kathryn Lileth

    2013-01-01

    This study examined the inhibition deficit hypothesis in children with math disabilities (MD). Children with and without MD were compared on two inhibition tasks that included the random generation of numbers and letters. The results addressed three hypotheses. Weak support was found for the first hypothesis which stated difficulties related to inhibition are significantly related to math performance. I found partial support for this hypothesis in that inhibition was related to math problem s...

  15. Briefing paper for universities on Core Maths

    OpenAIRE

    Glaister, Paul

    2015-01-01

    This briefing paper outlines the rationale for and development of the new Core Maths qualifications, the characteristics of Core Maths, and why Core Maths is important for higher education. It is part of a communication to university vice-chancellors from the Department for Business, Innovation and Skills (BIS) comprising this paper and a joint Ministerial letter from Jo Johnson, Minister of State for Universities and Science in BIS, and Nick Gibb, Minister of State for Schools in the Departm...

  16. Teachers’ ability in using math learning media

    Science.gov (United States)

    Masniladevi; Prahmana, R. C. I.; Helsa, Y.; Dalais, M.

    2017-12-01

    The studies aim to enhance teachers’ knowledge and skill in making math instructional media, develop math instructional media, train and assist the use of instructional media in learning math in the classroom. The method used in the activities adopted the pattern of preventive implementation, planning stage, program implementation, observation and evaluation and reflection. The research results show that the evaluation of teachers’ ability is still in average category. The result required more intensive training.

  17. Numbers and other math ideas come alive

    CERN Document Server

    Pappas, Theoni

    2012-01-01

    Most people don't think about numbers, or take them for granted. For the average person numbers are looked upon as cold, clinical, inanimate objects. Math ideas are viewed as something to get a job done or a problem solved. Get ready for a big surprise with Numbers and Other Math Ideas Come Alive. Pappas explores mathematical ideas by looking behind the scenes of what numbers, points, lines, and other concepts are saying and thinking. In each story, properties and characteristics of math ideas are entertainingly uncovered and explained through the dialogues and actions of its math

  18. The Impact of MOVE IT Math(TM) and Traditional Textbook Instruction on Math Achievement Scores

    Science.gov (United States)

    Bennett, Angela Stephens

    2010-01-01

    One recommendation of government, education, and business leaders is an increased emphasis on math and science instruction in public schools. The purpose of this quantitative study using a posttest, quasi-experimental design was to determine if the Math Opportunities, Valuable Experiences, and Innovative Teaching (MOVE IT Math(TM)) program…

  19. The Effectiveness of Using STAR Math to Improve PSSA Math Scores

    Science.gov (United States)

    Holub, Sherry L.

    2017-01-01

    This is a quantitative study examining whether STAR Math, a student monitoring system, can improve PSSA Math scores. The experimental school used STAR Math during the 2015-2016 school year in grouping students for remediation and intervention. The control school used traditional curriculum measures to group students for remediation and…

  20. Using Brief Guided Imagery to Reduce Math Anxiety and Improve Math Performance: A Pilot Study

    Science.gov (United States)

    Henslee, Amber M.; Klein, Brandi A.

    2017-01-01

    The objective of this study was to investigate whether brief guided imagery could provide a short-term reduction in math anxiety and improve math performance. Undergraduates (N = 581) were screened for math anxiety, and the highest and lowest quartiles were recruited to participate in a lab-based study. Participants were assigned to a brief guided…

  1. Advanced Math Course Taking: Effects on Math Achievement and College Enrollment

    Science.gov (United States)

    Byun, Soo-yong; Irvin, Matthew J.; Bell, Bethany A.

    2015-01-01

    Using data from the Educational Longitudinal Study of 2002-2006, the authors investigated the effects of advanced math course taking on math achievement and college enrollment and how such effects varied by socioeconomic status and race/ethnicity. Results from propensity score matching and sensitivity analyses showed that advanced math course…

  2. Using an Intelligent Tutor and Math Fluency Training to Improve Math Performance

    Science.gov (United States)

    Arroyo, Ivon; Royer, James M.; Woolf, Beverly P.

    2011-01-01

    This article integrates research in intelligent tutors with psychology studies of memory and math fluency (the speed to retrieve or calculate answers to basic math operations). It describes the impact of computer software designed to improve either strategic behavior or math fluency. Both competencies are key to improved performance and both…

  3. Math Performance as a Function of Math Anxiety and Arousal Performance Theory

    Science.gov (United States)

    Farnsworth, Donald M., Jr.

    2009-01-01

    While research continues to link increased math anxiety with reduced working memory, the exact nature of the relationship remains elusive. In addition, research regarding the extent of the impact math anxiety has on working memory is contradictory. This research clarifies the directional nature of math anxiety as it pertains to working memory, and…

  4. The PANDA Endcap Disc DIRC

    Science.gov (United States)

    Föhl, K.; Ali, A.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Böhm, M.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Düren, M.; Etzelmüller, E.; Hayrapetyan, A.; Kreutzfeld, K.; Merle, O.; Rieke, J.; Schmidt, M.; Wasem, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2018-02-01

    Positively identifying charged kaons in the PANDA forward endcap solid angle range can be achieved with the Endcap Disc DIRC, allowing kaon-pion separation from 1 up to 4 GeV/c with a separation power of at least 3 standard deviations. Design, performance, and components of this DIRC are given, including the recently introduced TOFPET-ASIC based read-out. Results of a prototype operated in a test beam at DESY in 2016 are shown.

  5. Normal modes of Bardeen discs

    International Nuclear Information System (INIS)

    Verdaguer, E.

    1983-01-01

    The short wavelength normal modes of self-gravitating rotating polytropic discs in the Bardeen approximation are studied. The discs' oscillations can be seen in terms of two types of modes: the p-modes whose driving forces are pressure forces and the r-modes driven by Coriolis forces. As a consequence of differential rotation coupling between the two takes place and some mixed modes appear, their properties can be studied under the assumption of weak coupling and it is seen that they avoid the crossing of the p- and r-modes. The short wavelength analysis provides a basis for the classification of the modes, which can be made by using the properties of their phase diagrams. The classification is applied to the large wavelength modes of differentially rotating discs with strong coupling and to a uniformly rotating sequence with no coupling, which have been calculated in previous papers. Many of the physical properties and qualitative features of these modes are revealed by the analysis. (author)

  6. Word posets, with applications to Coxeter groups

    Directory of Open Access Journals (Sweden)

    Matthew J. Samuel

    2011-08-01

    Full Text Available We discuss the theory of certain partially ordered sets that capture the structure of commutation classes of words in monoids. As a first application, it follows readily that counting words in commutation classes is #P-complete. We then apply the partially ordered sets to Coxeter groups. Some results are a proof that enumerating the reduced words of elements of Coxeter groups is #P-complete, a recursive formula for computing the number of commutation classes of reduced words, as well as stronger bounds on the maximum number of commutation classes than were previously known. This also allows us to improve the known bounds on the number of primitive sorting networks.

  7. Math Anxiety and Math Performance in Children: The Mediating Roles of Working Memory and Math Self-Concept

    Science.gov (United States)

    Justicia-Galiano, M. José; Martín-Puga, M. Eva; Linares, Rocío; Pelegrina, Santiago

    2017-01-01

    Background: Numerous studies, most of them involving adolescents and adults, have evidenced a moderate negative relationship between math anxiety and math performance. There are, however, a limited number of studies that have addressed the mechanisms underlying this relation. Aims: This study aimed to investigate the role of two possible…

  8. The relation between math self-concept, test and math anxiety, achievement motivation and math achievement in 12 to 14-year-old typically developing adolescents

    NARCIS (Netherlands)

    Timmerman, H.L.; Toll, S.W.M.; van Luit, J.E.H.

    2017-01-01

    :This study examines the relation between math self-concept, test and math anxiety, achievement motivation, and math achievement in typically developing 12 to 14-year-old adolescents (N = 108) from a school for secondary education in the Netherlands. Data was obtained using a math speed test,

  9. On the relationship between math anxiety and math achievement in early elementary school: The role of problem solving strategies.

    Science.gov (United States)

    Ramirez, Gerardo; Chang, Hyesang; Maloney, Erin A; Levine, Susan C; Beilock, Sian L

    2016-01-01

    Even at young ages, children self-report experiencing math anxiety, which negatively relates to their math achievement. Leveraging a large dataset of first and second grade students' math achievement scores, math problem solving strategies, and math attitudes, we explored the possibility that children's math anxiety (i.e., a fear or apprehension about math) negatively relates to their use of more advanced problem solving strategies, which in turn relates to their math achievement. Our results confirm our hypothesis and, moreover, demonstrate that the relation between math anxiety and math problem solving strategies is strongest in children with the highest working memory capacity. Ironically, children who have the highest cognitive capacity avoid using advanced problem solving strategies when they are high in math anxiety and, as a result, underperform in math compared with their lower working memory peers. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Mathematics anxiety: separating the math from the anxiety.

    Science.gov (United States)

    Lyons, Ian M; Beilock, Sian L

    2012-09-01

    Anxiety about math is tied to low math grades and standardized test scores, yet not all math-anxious individuals perform equally poorly in math. We used functional magnetic resonance imaging to separate neural activity during the anticipation of doing math from activity during math performance itself. For higher (but not lower) math-anxious individuals, increased activity in frontoparietal regions when simply anticipating doing math mitigated math-specific performance deficits. This network included bilateral inferior frontal junction, a region involved in cognitive control and reappraisal of negative emotional responses. Furthermore, the relation between frontoparietal anticipatory activity and highly math-anxious individuals' math deficits was fully mediated (or accounted for) by activity in caudate, nucleus accumbens, and hippocampus during math performance. These subcortical regions are important for coordinating task demands and motivational factors during skill execution. Individual differences in how math-anxious individuals recruit cognitive control resources prior to doing math and motivational resources during math performance predict the extent of their math deficits. This work suggests that educational interventions emphasizing control of negative emotional responses to math stimuli (rather than merely additional math training) will be most effective in revealing a population of mathematically competent individuals, who might otherwise go undiscovered.

  11. Proto-planetary disc evolution and dispersal

    Science.gov (United States)

    Rosotti, Giovanni Pietro

    2015-05-01

    Planets form from gas and dust discs in orbit around young stars. The timescale for planet formation is constrained by the lifetime of these discs. The properties of the formed planetary systems depend thus on the evolution and final dispersal of the discs, which is the main topic of this thesis. Observations reveal the existence of a class of discs called "transitional", which lack dust in their inner regions. They are thought to be the last stage before the complete disc dispersal, and hence they may provide the key to understanding the mechanisms behind disc evolution. X-ray photoevaporation and planet formation have been studied as possible physical mechanisms responsible for the final dispersal of discs. However up to now, these two phenomena have been studied separately, neglecting any possible feedback or interaction. In this thesis we have investigated what is the interplay between these two processes. We show that the presence of a giant planet in a photo-evaporating disc can significantly shorten its lifetime, by cutting the inner regions from the mass reservoir in the exterior of the disc. This mechanism produces transition discs that for a given mass accretion rate have larger holes than in models considering only X-ray photo-evaporation, constituting a possible route to the formation of accreting transition discs with large holes. These discs are found in observations and still constitute a puzzle for the theory. Inclusion of the phenomenon called "thermal sweeping", a violent instability that can destroy a whole disc in as little as 10 4 years, shows that the outer disc left can be very short-lived (depending on the X-ray luminosity of the star), possibly explaining why very few non accreting transition discs are observed. However the mechanism does not seem to be efficient enough to reconcile with observations. In this thesis we also show that X-ray photo-evaporation naturally explains the observed correlation between stellar masses and accretion

  12. Girls Talk Math - Engaging Girls Through Math Media

    Science.gov (United States)

    Bernardi, Francesca; Morgan, Katrina

    2017-11-01

    ``Girls Talk Math: Engaging Girls through Math Media'' is a free two-week long summer day camp for high-school girls in the Triangle area of NC. This past June the camp had its second run thanks to renewed funding from the Mathematical Association of America Tensor Women and Mathematics Grant. The camp involved 35 local high-school students who identify as female. Campers complete challenging problem sets and research the life of a female scientist who worked on similar problems. They report their work in a blog post and record a podcast about the scientist they researched. The curriculum has been developed by Mathematics graduate students at UNC from an inquiry based learning perspective; problem sets topics include some theoretical mathematics, but also more applied physics-based material. Campers worked on fluid dynamics, special relativity, and quantum mechanics problem sets which included experiments. The camp has received positive feedback from the local community and the second run saw a large increase in the number of participants. The program is evaluated using pre and post surveys, which measure campers' confidence and interest in pursuing higher level courses in STEM. The results from the past two summers have been encouraging. Mathematical Association of America Tensor Women and Mathematics Grant.

  13. 80 Years of Zentralblatt MATH

    CERN Document Server

    Teschke, Olaf; Werner, Dirk

    2011-01-01

    Founded in 1931 by Otto Neugebauer as the printed documentation service "Zentralblatt fur Mathematik und ihre Grenzgebiete", Zentralblatt MATH (ZBMATH) celebrates its 80th anniversary in 2011. Today it is the most comprehensive and active reference database in pure and applied mathematics worldwide. Many prominent mathematicians have been involved in this service as reviewers or editors and have, like all mathematicians, left their footprints in ZBMATH, in a long list of entries describing all of their research publications in mathematics. This book provides one review from each of t

  14. Maths for the building trades

    CERN Document Server

    Kidd, Jim

    2014-01-01

    Maths for the Building Trades provides students of all ages with an easy-to-understand guide to the fundamental mathematics that is required in their area of study and beyond. It can be used as a learning programme on its own or in conjunction with the textbooks associated with their chosen trade. The book assumes only a minimum level of mathematical knowledge and thoroughly covers the basic rules. It then goes on to fully explain some of the more complex areas in which the student will be required to demonstrate competence.

  15. [Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

    Science.gov (United States)

    Liang, Hang; Deng, Xiangyu; Shao, Zengwu

    2017-10-01

    To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

  16. Combining Basic Business Math and Electronic Calculators.

    Science.gov (United States)

    Merchant, Ronald

    As a means of alleviating math anxiety among business students and of improving their business machine skills, Spokane Falls Community College offers a course in which basic business math skills are mastered through the use of desk top calculators. The self-paced course, which accommodates varying student skill levels, requires students to: (1)…

  17. Explaining Math Achievement: Personality, Motivation, and Trust

    Science.gov (United States)

    Kilic-Bebek, Ebru

    2009-01-01

    This study investigated the statistical significance of student trust next to the well-tested constructs of personality and motivation to determine whether trust is a significant predictor of course achievement in college math courses. Participants were 175 students who were taking undergraduate math courses in an urban public university. The…

  18. Childcare Quality and Preschoolers' Math Development

    Science.gov (United States)

    Choi, Ji Young; Dobbs-Oates, Jennifer

    2014-01-01

    This study examined the associations between four types of childcare quality (i.e. teacher-child closeness, frequency of math-related activities, and teacher education and experience) and preschoolers' residualised gain in math over the course of six months. Additionally, potential interactions between teacher-child closeness and other indicators…

  19. Football to Improve Math and Reading Performance

    Science.gov (United States)

    Van Klaveren, Chris; De Witte, Kristof

    2015-01-01

    Schools frequently increase the instructional time to improve primary school children's math and reading skills. There is, however, little evidence that math and reading skills are effectively improved by these instruction-time increases. This study evaluates "Playing for Success" (PfS), an extended school day program for underachieving…

  20. Five Keys for Teaching Mental Math

    Science.gov (United States)

    Olsen, James R.

    2015-01-01

    After studying the Common Core State Standards for Mathematics (CCSSM) and brain-based learning research, James Olsen believes mental math instruction in secondary school mathematics (grades 7-12) and in teacher education programs needs increased attention. The purpose of this article is to share some keys for teaching mental math. Olsen also…

  1. Mini-Portfolio on Math and Science.

    Science.gov (United States)

    Teaching PreK-8, 1996

    1996-01-01

    Presents six articles dealing with math and science education: "Sneaker Geometry" (Jack George), "Fairs with a Flair" (Diane McCarty), "Generating Excitement with Math Projects" (Jeffrey Kostecky and Louis Roe), "Playing with Numbers" (Diana Smith), "When Student Teachers Want to Do Hands-On Science" (Betsy Feldkamp-Price), and "Science ala Carte"…

  2. Football to improve math and reading performance

    NARCIS (Netherlands)

    Van Klaveren, Chris; De Witte, Kristof

    2015-01-01

    Schools frequently increase the instructional time to improve primary school children's math and reading skills. There is, however, little evidence that math and reading skills are effectively improved by these instruction-time increases. This study evaluates ‘Playing for Success’ (PfS), an extended

  3. Decreasing Math Anxiety in College Students

    Science.gov (United States)

    Perry, Andrew B.

    2004-01-01

    This paper examines the phenomenon of mathematics anxiety in contemporary college and university students. Forms of math anxiety range from moderate test anxiety to extreme anxiety including physiological symptoms such as nausea. For each of several types of math anxiety, one or more case studies is analyzed. Selected strategies for coping with…

  4. Is math anxiety in the secondary classroom limiting physics mastery? A study of math anxiety and physics performance

    Science.gov (United States)

    Mercer, Gary J.

    This quantitative study examined the relationship between secondary students with math anxiety and physics performance in an inquiry-based constructivist classroom. The Revised Math Anxiety Rating Scale was used to evaluate math anxiety levels. The results were then compared to the performance on a physics standardized final examination. A simple correlation was performed, followed by a multivariate regression analysis to examine effects based on gender and prior math background. The correlation showed statistical significance between math anxiety and physics performance. The regression analysis showed statistical significance for math anxiety, physics performance, and prior math background, but did not show statistical significance for math anxiety, physics performance, and gender.

  5. Biomaterials for intervertebral disc regeneration and repair.

    Science.gov (United States)

    Bowles, Robert D; Setton, Lori A

    2017-06-01

    The intervertebral disc contributes to motion, weight bearing, and flexibility of the spine, but is susceptible to damage and morphological changes that contribute to pathology with age and injury. Engineering strategies that rely upon synthetic materials or composite implants that do not interface with the biological components of the disc have not met with widespread use or desirable outcomes in the treatment of intervertebral disc pathology. Here we review bioengineering advances to treat disc disorders, using cell-supplemented materials, or acellular, biologically based materials, that provide opportunity for cell-material interactions and remodeling in the treatment of intervertebral disc disorders. While a field still in early development, bioengineering-based strategies employing novel biomaterials are emerging as promising alternatives for clinical treatment of intervertebral disc disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Development of rupture discs for the FBTR

    International Nuclear Information System (INIS)

    Chetal, S.C.; Raju, C.; Anandkumar, V.; Seetharaman, V.; Rajan, K.K.

    1984-01-01

    Rupture discs are required as a safety device for protecting the secondary sodium circuit and its components against high pressure surges due to accidental water steam leaks in sodium heated steam generator and the consequent sodium water reaction. For identical reasons, rupture discs are also required on the vessels used for decontamination of sodium components. Reverse buckling knife blade concept with austenitic stainless steel disc has been developed for the rupture disc assemblies required for Fast Breeder Test Reactor (FBTR). Hydroforming process without any die has been used for disc fabrication. One rupture disc assembly required for steam generator is undergoing sodium endurance test and has accumulated 4,500 hours. The present status of development work as demonstrated by room temperature experimental results as well as the scope for future work are discussed. (author)

  7. Phylogeny of the TRAF/MATH domain.

    Science.gov (United States)

    Zapata, Juan M; Martínez-García, Vanesa; Lefebvre, Sophie

    2007-01-01

    The TNF-receptor associated factor (TRAF) domain (TD), also known as the meprin and TRAF-C homology (MATH) domain is a fold of seven anti-parallel p-helices that participates in protein-protein interactions. This fold is broadly represented among eukaryotes, where it is found associated with a discrete set of protein-domains. Virtually all protein families encompassing a TRAF/MATH domain seem to be involved in the regulation of protein processing and ubiquitination, strongly suggesting a parallel evolution of the TRAF/MATH domain and certain proteolysis pathways in eukaryotes. The restricted number of living organisms for which we have information of their genetic and protein make-up limits the scope and analysis of the MATH domain in evolution. However, the available information allows us to get a glimpse on the origins, distribution and evolution of the TRAF/MATH domain, which will be overviewed in this chapter.

  8. Engaging Math-Avoidant College Students

    Directory of Open Access Journals (Sweden)

    M. Paul Latiolais

    2009-07-01

    Full Text Available This paper is an informal, personal account of how we, as two college teachers, became interested in math anxiety, decided to explore it amongst students at our institution in order to inform our teaching, and became convinced that the massive problem is math avoidance. We tried discussion groups, but few students attended, although those that did made useful suggestions. Thus informed, we designed an innovative course, Confronting College Mathematics as a Humanities course with the possibility of credit toward the math requirement, but it was undersubscribed in its first offering and had to be canceled. How can we get college students who avoid math to break through the barrier of math avoidance? We have now begun to explore a new approach: Second Life, where students can engage math—and quantitative literacy—virtually, and anonymously.

  9. Physiological pattern of lumbar disc height

    International Nuclear Information System (INIS)

    Biggemann, M.; Frobin, W.; Brinckmann, P.

    1997-01-01

    Purpose of this study is to present a new method of quantifying objectively the height of all discs in lateral radiographs of the lumbar spine and of analysing the normal craniocaudal sequence pattern of lumbar disc heights. Methods: The new parameter is the ventrally measured disc height corrected for the dependence on the angle of lordosis by normalisation to mean angles observed in the erect posture of healthy persons. To eliminate radiographic magnification, the corrected ventral height is related to the mean depth of the cranially adjoining vertebra. In this manner lumbar disc heights were objectively measured in young, mature and healthy persons (146 males and 65 females). The craniocaudal sequence pattern was analysed by mean values from all persons and by height differences of adjoining discs in each individual lumbar spine. Results: Mean normative values demonstrated an increase in disc height between L1/L2 and L4/L5 and a constant or decreasing disc height between L4/L5 and L5/S1. However, this 'physiological sequence of disc height in the statistical mean' was observed in only 36% of normal males and 55% of normal females. Conclusion: The radiological pattern of the 'physiological sequence of lumbar disc height' leads to a relevant portion of false positive pathological results especially at L4/L5. An increase of disc height from L4/L5 to L5/S1 may be normal. The recognition of decreased disc height should be based on an abrupt change in the heights of adjoining discs and not on a deviation from a craniocaudal sequence pattern. (orig.) [de

  10. Debris disc constraints on planetesimal formation

    Science.gov (United States)

    Krivov, Alexander V.; Ide, Aljoscha; Löhne, Torsten; Johansen, Anders; Blum, Jürgen

    2018-02-01

    Two basic routes for planetesimal formation have been proposed over the last decades. One is a classical `slow-growth' scenario. Another one is particle concentration models, in which small pebbles are concentrated locally and then collapse gravitationally to form planetesimals. Both types of models make certain predictions for the size spectrum and internal structure of newly born planetesimals. We use these predictions as input to simulate collisional evolution of debris discs left after the gas dispersal. The debris disc emission as a function of a system's age computed in these simulations is compared with several Spitzer and Herschel debris disc surveys around A-type stars. We confirm that the observed brightness evolution for the majority of discs can be reproduced by classical models. Further, we find that it is equally consistent with the size distribution of planetesimals predicted by particle concentration models - provided the objects are loosely bound `pebble piles' as these models also predict. Regardless of the assumed planetesimal formation mechanism, explaining the brightest debris discs in the samples uncovers a `disc mass problem'. To reproduce such discs by collisional simulations, a total mass of planetesimals of up to ˜1000 Earth masses is required, which exceeds the total mass of solids available in the protoplanetary progenitors of debris discs. This may indicate that stirring was delayed in some of the bright discs, that giant impacts occurred recently in some of them, that some systems may be younger than previously thought or that non-collisional processes contribute significantly to the dust production.

  11. Math

    Directory of Open Access Journals (Sweden)

    Srinivas Jangili

    2016-09-01

    Full Text Available The present study investigates the entropy generation in magnetized-micropolar fluid flow in between two vertical concentric rotating cylinders of infinite length. The surface of the inner cylinder is heated while the surface of the outer cylinder is cooled. Internal heat generation is incorporated. The Eringen thermo-micropolar fluid model is used to simulate the micro-structural rheological flow characteristics in the annulus region. The flow is subjected to a constant, static, axial magnetic field. The surface of the inner cylinder is prescribed to be isothermal whereas the surface of the outer cylinder was exposed to convection cooling. The conservation equations are normalized and closed-form solutions are obtained for the velocity, microrotation, temperature, entropy generation number, Bejan number and total entropy generation rate. The effects of the relevant parameters are displayed graphically. It is observed that the external magnetic force enhances the entropy production rate and it is maximum in the proximity of the inner cylinder. This causes more wear and tear at the surface of the inner cylinder. Greater Hartmann number also elevates microrotation values in the entire annulus region. The study is relevant to optimization of chemical engineering processes, nuclear engineering cooling systems and propulsion systems utilizing non-Newtonian fluids and magnetohydrodynamics.

  12. Strengthening maths learning dispositions through ‘math clubs’

    Directory of Open Access Journals (Sweden)

    Mellony Graven

    2016-02-01

    Full Text Available In this paper, I argue that the establishment of after-school mathematics clubs in early grades holds rich potential for supporting the development of increasingly participatory and sensemaking maths learning dispositions. Within the South African Numeracy Chair project, lead by the author, multiple after-school mathematics clubs have been set up for learners in Grades 3–6 across Eastern Cape schools. These clubs are a complementary initiative to teacher development, aimed at improving low levels of numeracy learning across the majority of schools in the province. Two sources of data, learner interviews and teacher questionnaires, from one case study club, are shared in this article to illuminate the potential such clubs hold in developing increasingly participatory mathematics learning dispositions.

  13. Mothers, Intrinsic Math Motivation, Arithmetic Skills, and Math Anxiety in Elementary School

    Science.gov (United States)

    Daches Cohen, Lital; Rubinsten, Orly

    2017-01-01

    Math anxiety is influenced by environmental, cognitive, and personal factors. Yet, the concurrent relationships between these factors have not been examined. To this end, the current study investigated how the math anxiety of 30 sixth graders is affected by: (a) mother’s math anxiety and maternal behaviors (environmental factors); (b) children’s arithmetic skills (cognitive factors); and (c) intrinsic math motivation (personal factor). A rigorous assessment of children’s math anxiety was made by using both explicit and implicit measures. The results indicated that accessible self-representations of math anxiety, as reflected by the explicit self-report questionnaire, were strongly affected by arithmetic skills. However, unconscious cognitive constructs of math anxiety, as reflected by the numerical dot-probe task, were strongly affected by environmental factors, such as maternal behaviors and mothers’ attitudes toward math. Furthermore, the present study provided preliminary evidence of intergenerational transmission of math anxiety. The conclusions are that in order to better understand the etiology of math anxiety, multiple facets of parenting and children’s skills should be taken into consideration. Implications for researchers, parents, and educators are discussed. PMID:29180973

  14. Mothers, Intrinsic Math Motivation, Arithmetic Skills, and Math Anxiety in Elementary School.

    Science.gov (United States)

    Daches Cohen, Lital; Rubinsten, Orly

    2017-01-01

    Math anxiety is influenced by environmental, cognitive, and personal factors. Yet, the concurrent relationships between these factors have not been examined. To this end, the current study investigated how the math anxiety of 30 sixth graders is affected by: (a) mother's math anxiety and maternal behaviors (environmental factors); (b) children's arithmetic skills (cognitive factors); and (c) intrinsic math motivation (personal factor). A rigorous assessment of children's math anxiety was made by using both explicit and implicit measures. The results indicated that accessible self-representations of math anxiety, as reflected by the explicit self-report questionnaire, were strongly affected by arithmetic skills. However, unconscious cognitive constructs of math anxiety, as reflected by the numerical dot-probe task, were strongly affected by environmental factors, such as maternal behaviors and mothers' attitudes toward math. Furthermore, the present study provided preliminary evidence of intergenerational transmission of math anxiety. The conclusions are that in order to better understand the etiology of math anxiety, multiple facets of parenting and children's skills should be taken into consideration. Implications for researchers, parents, and educators are discussed.

  15. Math Anxiety Is Related to Some, but Not All, Experiences with Math.

    Science.gov (United States)

    O'Leary, Krystle; Fitzpatrick, Cheryll L; Hallett, Darcy

    2017-01-01

    Math anxiety has been defined as unpleasant feelings of tension and anxiety that hinder the ability to deal with numbers and math in a variety of situations. Although many studies have looked at situational and demographic factors associated with math anxiety, little research has looked at the self-reported experiences with math that are associated with math anxiety. The present study used a mixed-methods design and surveyed 131 undergraduate students about their experiences with math through elementary school, junior high, and high school, while also assessing math anxiety, general anxiety, and test anxiety. Some reported experiences (e.g., support in high school, giving students plenty of examples) were significantly related to the level of math anxiety, even after controlling for general and test anxiety, but many other factors originally thought to be related to math anxiety did not demonstrate a relation in this study. Overall, this study addresses a gap in the literature and provides some suggestive specifics of the kinds of past experiences that are related to math anxiety and those that are not.

  16. Math Anxiety Is Related to Some, but Not All, Experiences with Math

    Directory of Open Access Journals (Sweden)

    Krystle O'Leary

    2017-12-01

    Full Text Available Math anxiety has been defined as unpleasant feelings of tension and anxiety that hinder the ability to deal with numbers and math in a variety of situations. Although many studies have looked at situational and demographic factors associated with math anxiety, little research has looked at the self-reported experiences with math that are associated with math anxiety. The present study used a mixed-methods design and surveyed 131 undergraduate students about their experiences with math through elementary school, junior high, and high school, while also assessing math anxiety, general anxiety, and test anxiety. Some reported experiences (e.g., support in high school, giving students plenty of examples were significantly related to the level of math anxiety, even after controlling for general and test anxiety, but many other factors originally thought to be related to math anxiety did not demonstrate a relation in this study. Overall, this study addresses a gap in the literature and provides some suggestive specifics of the kinds of past experiences that are related to math anxiety and those that are not.

  17. Mothers, Intrinsic Math Motivation, Arithmetic Skills, and Math Anxiety in Elementary School

    Directory of Open Access Journals (Sweden)

    Lital Daches Cohen

    2017-11-01

    Full Text Available Math anxiety is influenced by environmental, cognitive, and personal factors. Yet, the concurrent relationships between these factors have not been examined. To this end, the current study investigated how the math anxiety of 30 sixth graders is affected by: (a mother’s math anxiety and maternal behaviors (environmental factors; (b children’s arithmetic skills (cognitive factors; and (c intrinsic math motivation (personal factor. A rigorous assessment of children’s math anxiety was made by using both explicit and implicit measures. The results indicated that accessible self-representations of math anxiety, as reflected by the explicit self-report questionnaire, were strongly affected by arithmetic skills. However, unconscious cognitive constructs of math anxiety, as reflected by the numerical dot-probe task, were strongly affected by environmental factors, such as maternal behaviors and mothers’ attitudes toward math. Furthermore, the present study provided preliminary evidence of intergenerational transmission of math anxiety. The conclusions are that in order to better understand the etiology of math anxiety, multiple facets of parenting and children’s skills should be taken into consideration. Implications for researchers, parents, and educators are discussed.

  18. Local models of astrophysical discs

    Science.gov (United States)

    Latter, Henrik N.; Papaloizou, John

    2017-12-01

    Local models of gaseous accretion discs have been successfully employed for decades to describe an assortment of small-scale phenomena, from instabilities and turbulence, to dust dynamics and planet formation. For the most part, they have been derived in a physically motivated but essentially ad hoc fashion, with some of the mathematical assumptions never made explicit nor checked for consistency. This approach is susceptible to error, and it is easy to derive local models that support spurious instabilities or fail to conserve key quantities. In this paper we present rigorous derivations, based on an asympototic ordering, and formulate a hierarchy of local models (incompressible, Boussinesq and compressible), making clear which is best suited for a particular flow or phenomenon, while spelling out explicitly the assumptions and approximations of each. We also discuss the merits of the anelastic approximation, emphasizing that anelastic systems struggle to conserve energy unless strong restrictions are imposed on the flow. The problems encountered by the anelastic approximation are exacerbated by the disc's differential rotation, but also attend non-rotating systems such as stellar interiors. We conclude with a defence of local models and their continued utility in astrophysical research.

  19. Optic Disc Drusen in Children

    DEFF Research Database (Denmark)

    Malmqvist, Lasse; Li, Xiao Qiang; Eckmann, Christina L

    2017-01-01

    diameter and fetal birth and pubertal parameters are associated with the presence of ODD. METHODS: This observational, longitudinal population-based birth cohort study, with a nested case-control, included 1,406 children. Eye examinations were performed when the children were between 11 and 12 years of age....... Assessment was performed of optical coherence tomography (OCT) scans from 1,304 children with gradable enhanced depth imaging scans of the optic disc. RESULTS: ODD in one or both eyes were found in 13 (1.0%) of all children. All but one of the cases were found in children with scleral canal diameter...... in the lowest quartile (1,182-1,399 μm) in the nested case-control study. Children with ODD had a mean disc diameter of 1,339 μm (interquartile range, 30 μm), whereas it was 1,508 μm (interquartile range, 196 μm) in the 130 controls without ODD (P

  20. Minimum weight design of inhomogeneous rotating discs

    International Nuclear Information System (INIS)

    Jahed, Hamid; Farshi, Behrooz; Bidabadi, Jalal

    2005-01-01

    There are numerous applications for gas turbine discs in the aerospace industry such as in turbojet engines. These discs normally work under high temperatures while subjected to high angular velocities. Minimizing the weight of such items in aerospace applications results in benefits such as low dead weights and lower costs. High speed of rotation causes large centrifugal forces in a disc and simultaneous application of high temperatures reduces disc material strength. Thus, the latter effects tend to increase deformations of the disc under the applied loads. In order to obtain a reliable disc analysis and arrive at the corresponding correct stress distribution, solutions should consider changes in material properties due to the temperature field throughout the disc. To achieve this goal, an inhomogeneous disc model with variable thickness is considered. Using the variable material properties method, stresses are obtained for the disc under rotation and a steady temperature field. In this paper this is done by modelling the rotating disc as a series of rings of different but constant properties. The optimum disc profile is arrived at by sequentially proportioning the thicknesses of each ring to satisfy the stress requirements. This method vis-a-vis a mathematical programming procedure for optimization shows several advantages. Firstly, it is simple iterative proportioning in each design cycle not requiring involved mathematical operations. Secondly, due to its simplicity it alleviates the necessity of certain simplifications that are common in so-called rigorous mathematical procedures. The results obtained, compared to those published in the literature show agreement and superiority. A further advantage of the proposed method is the independence of the end results from the initially assumed point in the iterative design routine, unlike most methods published so far

  1. Enhancing Mathematical Communication for Virtual Math Teams

    Directory of Open Access Journals (Sweden)

    Gerry Stahl

    2010-06-01

    Full Text Available The Math Forum is an online resource center for pre-algebra, algebra, geometry and pre-calculus. Its Virtual Math Teams (VMT service provides an integrated web-based environment for small teams of people to discuss math and to work collaboratively on math problems or explore interesting mathematical micro-worlds together. The VMT Project studies the online math discourse that takes place during sessions of virtual math teams working on open-ended problem-solving tasks. In particular, it investigates methods of group cognition that are employed by teams in this setting. The VMT environment currently integrates social networking, synchronous text chat, a shared whiteboard for drawing, web browsers and an asynchronous wiki for exchanging findings within the larger community. A simple version of MathML is supported in the whiteboard, chat and wiki for displaying mathematical expressions. The VMT Project is currently integrating the dynamic mathematics application, GeoGebra, into its collaboration environment. This will create a multi-user version of GeoGebra, which can be used in concert with the chat, web browsers, curricular topics and wiki repository.

  2. La maison des mathématiques

    CERN Document Server

    Villani, Cédric; Moncorgé, Vincent

    2014-01-01

    Comment travaillent les mathématiciens ? C'est peut-être en se promenant dans les couloirs de la première des " maisons des mathématiques " de France, l'institut Henri Poincaré, que l'on trouvera quelques réponses. Le mathématicien Cédric Villani et le physicien Jean-Philippe Uzan nous invitent à découvrir cette discipline et ses acteurs. Au fil des pages on suit, à travers de superbes images signées du photographe Vincent Moncorgé, la façon dont se fabrique cette science qui reste souvent mystérieuse. Toutes les dimensions, scientifique, esthétique et poétique, des mathématiques sont convoquées grâce à des regards croisés : la diversité des inspirations des chercheurs, la source de leur créativité, l'imaginaire littéraire et artistique des mathématiques, la drôle de tribu des mathématiciens. Un voyage au cœur de cette " auberge espagnole " des mathématiques, campus " à la française " accueillant des centaines de chercheurs du monde entier, devenu un lieu d'émulation et d'éc...

  3. The neurodevelopmental basis of math anxiety.

    Science.gov (United States)

    Young, Christina B; Wu, Sarah S; Menon, Vinod

    2012-05-01

    Math anxiety is a negative emotional reaction to situations involving mathematical problem solving. Math anxiety has a detrimental impact on an individual's long-term professional success, but its neurodevelopmental origins are unknown. In a functional MRI study on 7- to 9-year-old children, we showed that math anxiety was associated with hyperactivity in right amygdala regions that are important for processing negative emotions. In addition, we found that math anxiety was associated with reduced activity in posterior parietal and dorsolateral prefrontal cortex regions involved in mathematical reasoning. Multivariate classification analysis revealed distinct multivoxel activity patterns, which were independent of overall activation levels in the right amygdala. Furthermore, effective connectivity between the amygdala and ventromedial prefrontal cortex regions that regulate negative emotions was elevated in children with math anxiety. These effects were specific to math anxiety and unrelated to general anxiety, intelligence, working memory, or reading ability. Our study identified the neural correlates of math anxiety for the first time, and our findings have significant implications for its early identification and treatment.

  4. Math-Gender Stereotypes in Elementary School Children

    Science.gov (United States)

    Cvencek, Dario; Meltzoff, Andrew N.; Greenwald, Anthony G.

    2011-01-01

    A total of 247 American children between 6 and 10 years of age (126 girls and 121 boys) completed Implicit Association Tests and explicit self-report measures assessing the association of (a) "me" with "male" (gender identity), (b) "male" with "math" (math-gender stereotype), and (c) "me" with "math" (math self-concept). Two findings emerged.…

  5. More than Counting: Whole Math Activities for Preschool and Kindergarten.

    Science.gov (United States)

    Moomaw, Sally; Hieronymus, Brenda

    This book presents extensive sampling of a "whole math" curriculum for preschool and kindergarten children ages 3 and older. An introductory chapter is followed by seven curriculum chapters that discuss math manipulatives, collections, grid games, path games, graphing, math and gross-motor play, and the "math suitcase." Each chapter is divided…

  6. A Simulation Model of Focus and Radial Servos in Compact Disc Players with Disc Surface Defects

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2004-01-01

    Compact Disc players have been on the market in more than two decades.As a consequence most of the control servo problems have been solved. A large remaining problem to solve is the handling of Compact Discs with severe surface defects like scratches and fingerprints. This paper introduces a method...... for making the design of controllers handling surface defects easier. A simulation model of Compact Disc players playing discs with surface defects is presented. The main novel element in the model is a model of the surface defects. That model is based on data from discs with surface defects. This model...

  7. Intervertebral disc herniation: prevalence and association with ...

    African Journals Online (AJOL)

    Background: Low back pain is one of the common health problems encountered in life with intervertebral disc herniation being a common cause of its occurrence. Magnetic resonance imaging has emerged the gold standard for diagnosing a herniated disc. Aims and Objectives: To assess the frequency and pattern of ...

  8. The evolution of stellar exponential discs

    NARCIS (Netherlands)

    Ferguson, AMN; Clarke, CJ

    2001-01-01

    Models of disc galaxies which invoke viscosity-driven radial flows have long been known to provide a natural explanation for the origin of stellar exponential discs, under the assumption that the star formation and viscous time-scales are comparable. We present models which invoke simultaneous star

  9. Feature Based Control of Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh

    Two servo control loops are used to keep the Optical Pick-up Unit focused and radially on the information track of the Compact Disc. These control servos have problems handling surface faults on the Compact Disc. In this Ph.D thesis a method is proposed to improve the handling of these surface...

  10. Robust control of a compact disc mechanism

    NARCIS (Netherlands)

    Steinbuch, M.; Schootstra, G.; Bosgra, O.H.; Levine, W.S.

    1995-01-01

    A compact disc (CD) player is an optical decoding device that reproduces high-quality audio from a digitally coded signal recorded as a spiral-shaped track on a reflective disc. Apart from the audio application, other optical data systems (CD-ROM, optical data drive) and combined audio/video

  11. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  12. Use NASA GES DISC Data in ArcGIS

    Science.gov (United States)

    Yang, Wenli; Pham, Long B.; Kempler, Steve

    2015-01-01

    This presentation describes GIS relevant data at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), GES DISC Services and Support for GIS Users, and use cases of GES DISC data in ArcGIS.

  13. Math and Gender: Is Math a Route to a High-Powered Career?

    DEFF Research Database (Denmark)

    Joensen, Juanna Schrøter; Nielsen, Helena Skyt

    There is a large gender gap in advanced math coursework in high school that many believe exists because girls are discouraged from taking math courses. In this paper, we exploit an institutional change that reduced the costs of acquiring advanced high school math to determine if access is, in fact......, the mechanism - in particular for girls at the top of the math ability distribution. By estimating marginal treatment effects of acquiring advanced math qualifications, we document substantial beneficial wage effects from encouraging even more females to opt for these qualifications. Our analysis suggests...... that the beneficial effect comes from accelerating graduation and attracting females to high-paid or traditionally male-dominated career tracks and to CEO positions. Our results may be reconciled with experimental and empirical evidence suggesting there is a pool of unexploited math talent among high ability girls...

  14. Affective and motivational factors mediate the relation between math skills and use of math in everyday life

    NARCIS (Netherlands)

    Jansen, B.R.J.; Schmitz, E.A.; van der Maas, H.L.J.

    2016-01-01

    This study focused on the use of math in everyday life (the propensity to recognize and solve quantitative issues in real life situations). Data from a Dutch nation-wide research on math among adults (N = 521) were used to investigate the question whether math anxiety and perceived math competence

  15. Turning Negatives into Positives: The Role of an Instructional Math Course on Preservice Teachers' Math Beliefs

    Science.gov (United States)

    Looney, Lisa; Perry, David; Steck, Andy

    2017-01-01

    Teachers' beliefs about mathematics can play a role in their teaching effectiveness (Bandura, 1993). Negative attitudes toward math (e.g., math anxiety) or low self-efficacy beliefs for teaching math can act as barriers to the teaching process, impacting the achievement and math beliefs of students (Beilock, Gunderson, Ramirez, & Levine, 2010;…

  16. An Investigation of Boys' and Girls' Emotional Experience of Math, Their Math Performance, and the Relation between These Variables

    Science.gov (United States)

    Erturan, Selin; Jansen, Brenda

    2015-01-01

    Gender differences in children's emotional experience of math, their math performance, and the relation between these variables were investigated in two studies. In Study 1, test anxiety, math anxiety, and math performance (whole-number computation) were measured in 134 children in grades 3-8 (ages 7-15 years). In Study 2, perceived math…

  17. An investigation of boys’ and girls’ emotional experience of math, their math performance, and the relation between these variables

    NARCIS (Netherlands)

    Erturan, S; Jansen, B.

    2015-01-01

    GGender differences in children’s emotional experience of math, their math performance, and the relation between these variables were investigated in two studies. In Study 1, test anxiety, math anxiety, and math performance (whole-number computation) were measured in 134 children in grades 3-8 (ages

  18. Math Practice and Its Influence on Math Skills and Executive Functions in Adolescents with Mild to Borderline Intellectual Disability

    Science.gov (United States)

    Jansen, Brenda R. J.; De Lange, Eva; Van der Molen, Mariet J.

    2013-01-01

    Adolescents with mild to borderline intellectual disability (MBID) often complete schooling without mastering basic math skills, even though basic math is essential for math-related challenges in everyday life. Limited attention to cognitive skills and low executive functioning (EF) may cause this delay. We aimed to improve math skills in an…

  19. Magnetic resonance imaging of intervertebral disc degeneration

    International Nuclear Information System (INIS)

    Maeda, Hiroshi; Noguchi, Masao; Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi.

    1993-01-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.)

  20. Magnetic resonance imaging of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi

    1993-02-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

  1. The formation of planets by disc fragmentation

    Directory of Open Access Journals (Sweden)

    Stamatellos Dimitris

    2013-04-01

    Full Text Available I discuss the role that disc fragmentation plays in the formation of gas giant and terrestrial planets, and how this relates to the formation of brown dwarfs and low-mass stars, and ultimately to the process of star formation. Protostellar discs may fragment, if they are massive enough and can cool fast enough, but most of the objects that form by fragmentation are brown dwarfs. It may be possible that planets also form, if the mass growth of a proto-fragment is stopped (e.g. if this fragment is ejected from the disc, or suppressed and even reversed (e.g by tidal stripping. I will discuss if it is possible to distinguish whether a planet has formed by disc fragmentation or core accretion, and mention of a few examples of observed exoplanets that are suggestive of formation by disc fragmentation.

  2. T1 hyperintense disc in alkaptonuria.

    Science.gov (United States)

    Sag, Alan A; Silbergleit, Richard; Olson, Rick E; Wilson, Jon; Krishnan, Anant

    2012-10-01

    Case report. To report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation. A 46-year-old man without previous diagnosis of alkaptonuria underwent evaluation for progressive back pain revealing a T1-hyperintense disc herniation at the L3-L4 level. Discectomy recovered a blackened disc that was pathologically confirmed to be nucleus pulposus with alkaptonuric involvement. The differential diagnosis of a T1-hyperintense, T2-hypointense disc on magnetic resonance imaging is discussed, with emphasis on the pathophysiology of alkaptonuria. A single patient is reported. Pathologically proven patient presentation with radiological and pathological images. We report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation.

  3. Neural correlates of math anxiety – an overview and implications

    OpenAIRE

    Artemenko, Christina; Daroczy, Gabriella; Nuerk, Hans-Christoph

    2015-01-01

    Math anxiety is a common phenomenon which can have a negative impact on numerical and arithmetic performance. However, so far little is known about the underlying neurocognitive mechanisms. This mini review provides an overview of studies investigating the neural correlates of math anxiety which provide several hints regarding its influence on math performance: while behavioral studies mostly observe an influence of math anxiety on difficult math tasks, neurophysiological studies show that pr...

  4. Symbolic math for computation of radiation shielding

    International Nuclear Information System (INIS)

    Suman, Vitisha; Datta, D.; Sarkar, P.K.; Kushwaha, H.S.

    2010-01-01

    Radiation transport calculations for shielding studies in the field of accelerator technology often involve intensive numerical computations. Traditionally, radiation transport equation is solved using finite difference scheme or advanced finite element method with respect to specific initial and boundary conditions suitable for the geometry of the problem. All these computations need CPU intensive computer codes for accurate calculation of scalar and angular fluxes. Computation using symbols of the analytical expression representing the transport equation as objects is an enhanced numerical technique in which the computation is completely algorithm and data oriented. Algorithm on the basis of symbolic math architecture is developed using Symbolic math toolbox of MATLAB software. Present paper describes the symbolic math algorithm and its application as a case study in which shielding calculation of rectangular slab geometry is studied for a line source of specific activity. Study of application of symbolic math in this domain evolves a new paradigm compared to the existing computer code such as DORT. (author)

  5. Math: The Gateway to Great Careers

    Science.gov (United States)

    Ploutz-Snyder, Robert

    2010-01-01

    This slide presentation examines the role of mathematical proficiency and how it relates to advantages in careers. It emphasises the role of math in attaining entrance to college, graduate schools, and a career that is interesting and well paying.

  6. Developing Mathematical Resilience of Prospective Math Teachers

    Science.gov (United States)

    Ariyanto, L.; Herman, T.; Sumarmo, U.; Suryadi, D.

    2017-09-01

    Prospective math teachers need to develop positive adaptive attitudes toward mathematics that will enable them to continue learning despite having to deal with obstacles and difficulties. This research focuses on the resilience improvement of the prospective mathematic teachers after being treated using problem-based learning based on their basic knowledge on mathematic and their overall knowledge on math. This research used only one group for pre-test and post-test. The result of this research shows that there is improvement on prospective teachers’ resilience after they were given treatment using problem-based learning. One of the factors causing the resilience improvement of the prospective mathematic teachers is the instructions on students’ work sheet. In the instructions, stud ents were asked to write difficulties in solving math problems as well as write down the solution they take to overcome them. This research can be used as a reference for other researchers who want to do the same research related on students’ resiliency o n math and or math lecturers to improve the resilience of prospective teachers to be resilient teachers on math in the future.

  7. Understanding the Home Math Environment and Its Role in Predicting Parent Report of Children’s Math Skills

    Science.gov (United States)

    Ganley, Colleen M.; Purpura, David J.

    2016-01-01

    There is a growing literature concerning the role of the home math environment in children’s math development. In this study, we examined the relation between these constructs by specifically addressing three goals. The first goal was to identify the measurement structure of the home math environment through a series of confirmatory factor analyses. The second goal was to examine the role of the home math environment in predicting parent report of children’s math skills. The third goal was to test a series of potential alternative explanations for the relation between the home math environment and parent report of children’s skills, specifically the direct and indirect role of household income, parent math anxiety, and parent math ability as measured by their approximate number system performance. A final sample of 339 parents of children aged 3 through 8 drawn from Mechanical Turk answered a questionnaire online. The best fitting model of the home math environment was a bifactor model with a general factor representing the general home math environment, and three specific factors representing the direct numeracy environment, the indirect numeracy environment, and the spatial environment. When examining the association of the home math environment factors to parent report of child skills, the general home math environment factor and the spatial environment were the only significant predictors. Parents who reported doing more general math activities in the home reported having children with higher math skills, whereas parents who reported doing more spatial activities reported having children with lower math skills. PMID:28005925

  8. Intervertebral Disc Characteristic on Progressive Neurological Deficit

    Directory of Open Access Journals (Sweden)

    Farid Yudoyono

    2017-09-01

    Full Text Available Objective: To examine the intervertebral disc characteristic on magnetic resonance imaging (MRI in lumbar herniated disc (LHD patients with progressive neurological deficit. Methods: Patients were collected retrospectively from Dr. Hasan Sadikin General Hospital Database from 2011–2013 with LHD, had neurological deficit such as radiculopathy and cauda equine syndrome for less than four weeks with a positive sign confirmed by neurological examination and confirmatory with MRI examination. Results: A total of 14 patients with lumbar herniated disc disease (10 males, 4 females suffered from progressive neurological deficit with an average age of (52.07±10.9 years old. Early disc height was 9.38±0.5 mm and progressive neurological deficit state disc height was 4.03±0.53 mm, which were significantly different statisticaly (p<0.01. Symptoms of radiculopathy were seen in 11 patients and cauda equine syndrome in three patients. Modic changes grade 1 was found in five patients, grade 2 in eight patients,grade 3 in one patient, Pfirmman grade 2 in eleven patients and grade 3 in three patients. Thecal sac compression 1/3 compression was seen in four patients and 2/3 compression in ten patients. Conclusions: Neurosurgeon should raise concerns on the characteristic changes of intervertebral disc in magnetic resonance imaging examination to avoid further neural injury in lumbar herniated disc patients.

  9. Deep-down ionization of protoplanetary discs

    Science.gov (United States)

    Glassgold, A. E.; Lizano, S.; Galli, D.

    2017-12-01

    The possible occurrence of dead zones in protoplanetary discs subject to the magneto-rotational instability highlights the importance of disc ionization. We present a closed-form theory for the deep-down ionization by X-rays at depths below the disc surface dominated by far-ultraviolet radiation. Simple analytic solutions are given for the major ion classes, electrons, atomic ions, molecular ions and negatively charged grains. In addition to the formation of molecular ions by X-ray ionization of H2 and their destruction by dissociative recombination, several key processes that operate in this region are included, e.g. charge exchange of molecular ions and neutral atoms and destruction of ions by grains. Over much of the inner disc, the vertical decrease in ionization with depth into the disc is described by simple power laws, which can easily be included in more detailed modelling of magnetized discs. The new ionization theory is used to illustrate the non-ideal magnetohydrodynamic effects of Ohmic, Hall and Ambipolar diffusion for a magnetic model of a T Tauri star disc using the appropriate Elsasser numbers.

  10. Likelihood inference for unions of interacting discs

    DEFF Research Database (Denmark)

    Møller, Jesper; Helisova, K.

    2010-01-01

    This is probably the first paper which discusses likelihood inference for a random set using a germ-grain model, where the individual grains are unobservable, edge effects occur and other complications appear. We consider the case where the grains form a disc process modelled by a marked point...... process, where the germs are the centres and the marks are the associated radii of the discs. We propose to use a recent parametric class of interacting disc process models, where the minimal sufficient statistic depends on various geometric properties of the random set, and the density is specified......-based maximum likelihood inference and the effect of specifying different reference Poisson models....

  11. Spectroscopic Parameters of Lumbar Intervertebral Disc Material

    Science.gov (United States)

    Terbetas, G.; Kozlovskaja, A.; Varanius, D.; Graziene, V.; Vaitkus, J.; Vaitkuviene, A.

    2009-06-01

    There are numerous methods of investigating intervertebral disc. Visualization methods are widely used in clinical practice. Histological, imunohistochemical and biochemical methods are more used in scientific research. We propose that a new spectroscopic investigation would be useful in determining intervertebral disc material, especially when no histological specimens are available. Purpose: to determine spectroscopic parameters of intervertebral disc material; to determine emission spectra common for all intervertebral discs; to create a background for further spectroscopic investigation where no histological specimen will be available. Material and Methods: 20 patients, 68 frozen sections of 20 μm thickness from operatively removed intervertebral disc hernia were excited by Nd:YAG microlaser STA-01-TH third harmonic 355 nm light throw 0, 1 mm fiber. Spectrophotometer OceanOptics USB2000 was used for spectra collection. Mathematical analysis of spectra was performed by ORIGIN multiple Gaussian peaks analysis. Results: In each specimen of disc hernia were found distinct maximal spectral peaks of 4 types supporting the histological evaluation of mixture content of the hernia. Fluorescence in the spectral regions 370-700 nm was detected in the disc hernias. The main spectral component was at 494 nm and the contribution of the components with the peak wavelength values at 388 nm, 412 nm and 435±5 nm were varying in the different groups of samples. In comparison to average spectrum of all cases, there are 4 groups of different spectral signatures in the region 400-500 nm in the patient groups, supporting a clinical data on different clinical features of the patients. Discussion and Conclusion: besides the classical open discectomy, new minimally invasive techniques of treating intervertebral disc emerge (PLDD). Intervertebral disc in these techniques is assessed by needle, no histological specimen is taken. Spectroscopic investigation via fiber optics through the

  12. On the Leaky Math Pipeline: Comparing Implicit Math-Gender Stereotypes and Math Withdrawal in Female and Male Children and Adolescents

    Science.gov (United States)

    Steffens, Melanie C.; Jelenec, Petra; Noack, Peter

    2010-01-01

    Many models assume that habitual human behavior is guided by spontaneous, automatic, or implicit processes rather than by deliberate, rule-based, or explicit processes. Thus, math-ability self-concepts and math performance could be related to implicit math-gender stereotypes in addition to explicit stereotypes. Two studies assessed at what age…

  13. The Aftermath of Remedial Math: Investigating the Low Rate of Certificate Completion among Remedial Math Students

    Science.gov (United States)

    Bahr, Peter Riley

    2013-01-01

    Nationally, a majority of community college students require remedial assistance with mathematics, but comparatively few students who begin the remedial math sequence ultimately complete it and achieve college-level math competency. The academic outcomes of students who begin the sequence but do not complete it are disproportionately unfavorable:…

  14. Math Tracks: What Pace in Math Is Best for the Middle School Child?

    Science.gov (United States)

    Morrison, Michelle

    2011-01-01

    Mathematics is a critical part of academic preparation of the middle school child, or, as Dr. Maria Montessori would refer to them, children in the third plane of development. Montessori educators are sincere in their endeavors not only to prepare young students for further studies of math and the application of math in their world and careers,…

  15. Investigating Validity of Math 105 as Prerequisite to Math 201 among Undergraduate Students, Nigeria

    Science.gov (United States)

    Zakariya, Yusuf F.

    2016-01-01

    In this study, the author examined the validity of MATH 105 as a prerequisite to MATH 201. The data for this study was extracted directly from the examination results logic of the university. Descriptive statistics in form of correlations and linear regressions were used to analyze the obtained data. Three research questions were formulated and…

  16. Math and Movement: Practical Ways to Incorporate Math into Physical Education

    Science.gov (United States)

    Wade, Marcia

    2016-01-01

    Each year, physical educators are asked to incorporate even more math, language arts, science and social studies into their curriculum. The challenge is how to do this without sacrificing the essential health and life skills provided by a quality physical education program. One program, Math & Movement, is a great aid for physical educators to…

  17. The Effects of the Elevate Math Summer Program on Math Achievement and Algebra Readiness

    Science.gov (United States)

    Snipes, Jason; Huang, Chun-Wei; Jaquet, Karina; Finkelstein, Neal

    2016-01-01

    To raise math success rates in middle school, many schools and districts have implemented summer math programs designed to improve student preparation for algebra content in grade 8. However, little is known about the effectiveness of these programs. While students who participate typically experience learning gains, there is little rigorous…

  18. Gender compatibility, math-gender stereotypes, and self-concepts in math and physics

    Science.gov (United States)

    Koul, Ravinder; Lerdpornkulrat, Thanita; Poondej, Chanut

    2016-12-01

    [This paper is part of the Focused Collection on Gender in Physics.] Positive self-assessment of ability in the quantitative domains is considered critical for student participation in science, technology, engineering, and mathematics field studies. The present study investigated associations of gender compatibility (gender typicality and contentedness) and math-gender stereotypes with self-concepts in math and physics. Statistical analysis of survey data was based on a sample of 170 male and female high school science students matched on propensity scores based on age and past GPA scores in math. Results of MANCOVA analyses indicated that the combination of high personal gender compatibility with low endorsement of math-gender stereotypes was associated with low gender differentials in math and physics self-concepts whereas the combination of high personal gender compatibility with high endorsement of math-gender stereotypes was associated with high gender differentials in math and physics self-concepts. These results contribute to the recent theoretical and empirical work on antecedents to the math and physics identities critical to achieving gender equity in STEM fields.

  19. Evaluation of the MIND Research Institute's Spatial-Temporal Math (ST Math) Program in California

    Science.gov (United States)

    Wendt, Staci; Rice, John; Nakamoto, Jonathan

    2014-01-01

    The MIND Research Institute contracted with the Evaluation Research Program at WestEd to conduct an independent assessment of mathematics outcomes in elementary school grades across California that were provided with the ST Math program. Spatial-Temporal (ST) Math is a game-based instructional software designed to boost K-5 and secondary-level…

  20. Literacy Specialists in Math Class! Closing the Achievement Gap on State Math Assessments

    Science.gov (United States)

    DiGisi, Lori L.; Fleming, Dianne

    2005-01-01

    Sixth and eighth grade students who are English language learners must be able to read and interpret 39 math word problems in order to successfully calculate the answers on the Massachusetts state math assessment (MCAS). The first year that MCAS was administered, many ELL students read the questions, found them confusing, and left them blank,…

  1. Math Academy: Are You Game? Explorations in Probability. Supplemental Math Materials for Grades 3-6

    Science.gov (United States)

    Rimbey, Kimberly

    2007-01-01

    Created by teachers for teachers, the Math Academy tools and activities included in this booklet were designed to create hands-on activities and a fun learning environment for the teaching of mathematics to the students. This booklet contains the themed program "Are You Game? Math Academy--Explorations in Probability," which teachers can use to…

  2. Gender Compatibility, Math-Gender Stereotypes, and Self-Concepts in Math and Physics

    Science.gov (United States)

    Koul, Ravinder; Lerdpornkulrat, Thanita; Poondej, Chanut

    2016-01-01

    Positive self-assessment of ability in the quantitative domains is considered critical for student participation in science, technology, engineering, and mathematics field studies. The present study investigated associations of gender compatibility (gender typicality and contentedness) and math-gender stereotypes with self-concepts in math and…

  3. Math Anxiety and the "Math Gap": How Attitudes toward Mathematics Disadvantages Students as Early as Preschool

    Science.gov (United States)

    Geist, Eugene

    2015-01-01

    This study was conducted to examine the attitudes of Head Start teachers toward mathematics and how it may influence how and what they teach in the classroom. In general, the findings of this study can be summarized as this: 1) Math anxiety affects how teachers assess their ability at mathematics. The more math anxiety they report, the lower they…

  4. Math Is Like a Scary Movie? Helping Young People Overcome Math Anxiety

    Science.gov (United States)

    Kulkin, Margaret

    2016-01-01

    Afterschool teachers who tutor students or provide homework help have a unique opportunity to help students overcome the social or emotional barriers that so often block learning. They can embrace a creative and investigative approach to math learning. Margaret Kulkin's interest in being a math attitude "myth-buster" led her to apply to…

  5. Improving Student Achievement in Math and Science

    Science.gov (United States)

    Sullivan, Nancy G.; Hamsa, Irene Schulz; Heath, Panagiota; Perry, Robert; White, Stacy J.

    1998-01-01

    As the new millennium approaches, a long anticipated reckoning for the education system of the United States is forthcoming, Years of school reform initiatives have not yielded the anticipated results. A particularly perplexing problem involves the lack of significant improvement of student achievement in math and science. Three "Partnership" projects represent collaborative efforts between Xavier University (XU) of Louisiana, Southern University of New Orleans (SUNO), Mississippi Valley State University (MVSU), and the National Aeronautics and Space Administration (NASA), Stennis Space Center (SSC), to enhance student achievement in math and science. These "Partnerships" are focused on students and teachers in federally designated rural and urban empowerment zones and enterprise communities. The major goals of the "Partnerships" include: (1) The identification and dissemination of key indices of success that account for high performance in math and science; (2) The education of pre-service and in-service secondary teachers in knowledge, skills, and competencies that enhance the instruction of high school math and science; (3) The development of faculty to enhance the quality of math and science courses in institutions of higher education; and (4) The incorporation of technology-based instruction in institutions of higher education. These goals will be achieved by the accomplishment of the following objectives: (1) Delineate significant ?best practices? that are responsible for enhancing student outcomes in math and science; (2) Recruit and retain pre-service teachers with undergraduate degrees in Biology, Math, Chemistry, or Physics in a graduate program, culminating with a Master of Arts in Curriculum and Instruction; (3) Provide faculty workshops and opportunities for travel to professional meetings for dissemination of NASA resources information; (4) Implement methodologies and assessment procedures utilizing performance-based applications of higher order

  6. Thermal analysis on motorcycle disc brake geometry

    Science.gov (United States)

    W. M. Zurin W., S.; Talib, R. J.; Ismail, N. I.

    2017-08-01

    Braking is a phase of slowing and stop the movement of motorcycle. During braking, the frictional heat was generated and the energy was ideally should be faster dissipated to surrounding to prevent the built up of the excessive temperature which may lead to brake fluid vaporization, thermoelastic deformation at the contact surface, material degradation and failure. In this paper, solid and ventilated type of motorcycle disc brake are being analyse using Computational Fluid Dynamic (CFD) software. The main focus of the analysis is the thermal behaviour during braking for solid and ventilated disc brake. A comparison between both geometries is being discussed to determine the better braking performance in term of temperature distribution. It is found that ventilated disc brake is having better braking performance in terms of heat transfer compare to solid disc.

  7. Hydrodynamic forces on two moving discs

    Directory of Open Access Journals (Sweden)

    Burton D.A.

    2004-01-01

    Full Text Available We give a detailed presentation of a flexible method for constructing explicit expressions of irrotational and incompressible fluid flows around two rigid circular moving discs. We also discuss how such expressions can be used to compute the fluid-induced forces and torques on the discs in terms of Killing drives. Conformal mapping techniques are used to identify a meromorphic function on an annular region in C with a flow around two circular discs by a Mobius transformation. First order poles in the annular region correspond to vortices outside of the two discs. Inflows are incorporated by putting a second order pole at the point in the annulus that corresponds to infinity.

  8. Locally prepared antibiotic sensitivity discs: a substitute for imported ...

    African Journals Online (AJOL)

    Zones of inhibition were compared with those obtained from commercial antibiotic discs. Results obtained showed that discs prepared locally from antibiotic tablets, performed comparably with commercially obtained discs. There was no significant statistical difference between the two tested discs. We therefore recommend ...

  9. Optic Disc Pit with Sectorial Retinitis Pigmentosa

    OpenAIRE

    Balikoglu-Yilmaz, Melike; Taskapili, Muhittin; Yilmaz, Tolga; Teke, Mehmet Yasin

    2013-01-01

    Sectorial retinitis pigmentosa (RP) and optic disc pit (ODP) are rare clinical conditions. We present a 40-year-old woman with a history of mild night blindness and decreased vision in the right eye for about 5 years. Fundus examination revealed retinal pigmentary changes in the superior and inferotemporal sectors covering the macula and reduced arterial calibre and ODP at the temporal edge of the optic disc. In addition, fundus autofluorescence, spectral-domain optical coherence tomography, ...

  10. The lowest surface brightness disc galaxy known

    International Nuclear Information System (INIS)

    Davies, J.I.; Phillipps, S.; Disney, M.J.

    1988-01-01

    The discovery of a galaxy with a prominent bulge and a dominant extremely low surface brightness disc component is reported. The profile of this galaxy is very similar to the recently discovered giant low surface brightness galaxy Malin 1. The disc central surface brightness is found to be ∼ 26.4 Rμ, some 1.5 mag fainter than Malin 1 and thus by far the lowest yet observed. (author)

  11. Spontaneous Resolution of Optic Disc Pit Maculopathy

    OpenAIRE

    Tripathy, Koushik

    2017-01-01

    I read with interest the article reporting spontaneous resolution of optic disc pit maculopathy in a boy.1 Though the presence of an optic disc pit and associated macular involvement is undoubted in the presented case, the provided optical coherence tomography (OCT) does not clearly show typical intraretinal schisis (Figure 1B)1 at multiple retinal levels which may communicate with the pit. Instead, it shows a sub-internal limiting membrane (sub-ILM) cavity. Such cavities are known to occur f...

  12. Archival-grade optical disc design and international standards

    Science.gov (United States)

    Fujii, Toru; Kojyo, Shinichi; Endo, Akihisa; Kodaira, Takuo; Mori, Fumi; Shimizu, Atsuo

    2015-09-01

    Optical discs currently on the market exhibit large variations in life span among discs, making them unsuitable for certain business applications. To assess and potentially mitigate this problem, we performed accelerated degradation testing under standard ISO conditions, determined the probable disc failure mechanisms, and identified the essential criteria necessary for a stable disc composition. With these criteria as necessary conditions, we analyzed the physical and chemical changes that occur in the disc components, on the basis of which we determined technological measures to reduce these degradation processes. By applying these measures to disc fabrication, we were able to develop highly stable optical discs.

  13. The role of expressive writing in math anxiety.

    Science.gov (United States)

    Park, Daeun; Ramirez, Gerardo; Beilock, Sian L

    2014-06-01

    Math anxiety is a negative affective reaction to situations involving math. Previous work demonstrates that math anxiety can negatively impact math problem solving by creating performance-related worries that disrupt the working memory needed for the task at hand. By leveraging knowledge about the mechanism underlying the math anxiety-performance relationship, we tested the effectiveness of a short expressive writing intervention that has been shown to reduce intrusive thoughts and improve working memory availability. Students (N = 80) varying in math anxiety were asked to sit quietly (control group) prior to completing difficulty-matched math and word problems or to write about their thoughts and feelings regarding the exam they were about to take (expressive writing group). For the control group, high math-anxious individuals (HMAs) performed significantly worse on the math problems than low math-anxious students (LMAs). In the expressive writing group, however, this difference in math performance across HMAs and LMAs was significantly reduced. Among HMAs, the use of words related to anxiety, cause, and insight in their writing was positively related to math performance. Expressive writing boosts the performance of anxious students in math-testing situations. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  14. The new math of ownership.

    Science.gov (United States)

    Gross, B

    1998-01-01

    In 1994, when the software maker Knowledge Adventure decided to spin out a new venture--Worlds, Incorporated--founder Bill Gross expected the worst. He had argued with the board that it was in KA's best interests to maintain a controlling ownership stake in Worlds, whose powerful new software technology had enormous revenue potential. But the board prevailed, and KA took only a 20% ownership in the new company, giving the rest to Worlds' employees. Within a year, the company's performance had surpassed all expectations, and instead of owning 80% of a $5 million business, KA owned 20% of a $77 million business. The arithmetic may have been counterintuitive, but the lesson was clear. When KA let go of Worlds and gave its employees near total ownership, the company unleashed a new level of employee performance. That, in turn, led to the creation of economic value that more than made up for the equity KA had surrendered. So compelling was this "new math of ownership" that Gross founded a new company, Idealab, on this principle. The company, which develops ideas for Internet-based businesses and seeds the most promising ones, takes no more than a 49% equity stake in the new ventures and gives at least 1% of ownership to each employee. For Gross, this radical approach to ownership is the key to inspiring stellar performances. In part, employee-owners are motivated by their potential to earn great financial reward. But the drama of ownership, he argues, is even more important. In that drama, employees become personally involved in the struggle to outdo the competition and emerge victorious.

  15. Math practice and its influence on math skills and executive functions in adolescents with mild to borderline intellectual disability.

    Science.gov (United States)

    Jansen, Brenda R J; De Lange, Eva; Van der Molen, Mariët J

    2013-05-01

    Adolescents with mild to borderline intellectual disability (MBID) often complete schooling without mastering basic math skills, even though basic math is essential for math-related challenges in everyday life. Limited attention to cognitive skills and low executive functioning (EF) may cause this delay. We aimed to improve math skills in an MBID-sample using computerized math training. Also, it was investigated whether EF and math performance were related and whether computerized math training had beneficial effects on EF. The sample consisted of a total of 58 adolescents (12-15 years) from special education. Participants were randomly assigned to either the experimental group or a treatment as usual (TAU) group. In the experimental condition, participants received 5 weeks of training. Math performance and EF were assessed before and after the training period. Math performance improved equally in both groups. However, frequently practicing participants improved more than participants in the control group. Visuo-spatial memory skills were positively related to addition and subtraction skills. Transfer effects from math training to EF were absent. It is concluded that math skills may increase if a reasonable effort in practicing math skills is made. The relation between visuo-spatial memory skills provides opportunities for improving math performance. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Math at home adds up to achievement in school.

    Science.gov (United States)

    Berkowitz, Talia; Schaeffer, Marjorie W; Maloney, Erin A; Peterson, Lori; Gregor, Courtney; Levine, Susan C; Beilock, Sian L

    2015-10-09

    With a randomized field experiment of 587 first-graders, we tested an educational intervention designed to promote interactions between children and parents relating to math. We predicted that increasing math activities at home would increase children's math achievement at school. We tested this prediction by having children engage in math story time with their parents. The intervention, short numerical story problems delivered through an iPad app, significantly increased children's math achievement across the school year compared to a reading (control) group, especially for children whose parents are habitually anxious about math. Brief, high-quality parent-child interactions about math at home help break the intergenerational cycle of low math achievement. Copyright © 2015, American Association for the Advancement of Science.

  17. Elementary School Math Instruction: Can Reading Specialists Assist?

    Science.gov (United States)

    Heinrichs, Audrey S.

    1987-01-01

    Discusses the contradictions found in recommendations for direction instruction or informal math language development, and some suggestions for practical resolution of disagreements, to enable school reading specialists to provide both background and practical help to classroom instructors teaching math. (HTH)

  18. Minimum-complexity helicopter simulation math model

    Science.gov (United States)

    Heffley, Robert K.; Mnich, Marc A.

    1988-01-01

    An example of a minimal complexity simulation helicopter math model is presented. Motivating factors are the computational delays, cost, and inflexibility of the very sophisticated math models now in common use. A helicopter model form is given which addresses each of these factors and provides better engineering understanding of the specific handling qualities features which are apparent to the simulator pilot. The technical approach begins with specification of features which are to be modeled, followed by a build up of individual vehicle components and definition of equations. Model matching and estimation procedures are given which enable the modeling of specific helicopters from basic data sources such as flight manuals. Checkout procedures are given which provide for total model validation. A number of possible model extensions and refinement are discussed. Math model computer programs are defined and listed.

  19. Cervical disc hernia operations through posterior laminoforaminotomy.

    Science.gov (United States)

    Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

    2016-01-01

    The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  20. Cervical disc hernia operations through posterior laminoforaminotomy

    Directory of Open Access Journals (Sweden)

    Coskun Yolas

    2016-01-01

    Full Text Available Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years. Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%. On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  1. Only marginal alignment of disc galaxies

    Science.gov (United States)

    Andrae, René; Jahnke, Knud

    2011-12-01

    Testing theories of angular-momentum acquisition of rotationally supported disc galaxies is the key to understanding the formation of this type of galaxies. The tidal-torque theory aims to explain this acquisition process in a cosmological framework and predicts positive autocorrelations of angular-momentum orientation and spiral-arm handedness, i.e. alignment of disc galaxies, on short distance scales of 1 Mpc h-1. This disc alignment can also cause systematic effects in weak-lensing measurements. Previous observations claimed discovering these correlations but are overly optimistic in the reported level of statistical significance of the detections. Errors in redshift, ellipticity and morphological classifications were not taken into account, although they have a significant impact. We explain how to rigorously propagate all the important errors through the estimation process. Analysing disc galaxies in the Sloan Digital Sky Survey (SDSS) data base, we find that positive autocorrelations of spiral-arm handedness and angular-momentum orientations on distance scales of 1 Mpc h-1 are plausible but not statistically significant. Current data appear not good enough to constrain parameters of theory. This result agrees with a simple hypothesis test in the Local Group, where we also find no evidence for disc alignment. Moreover, we demonstrate that ellipticity estimates based on second moments are strongly biased by galactic bulges even for Scd galaxies, thereby corrupting correlation estimates and overestimating the impact of disc alignment on weak-lensing studies. Finally, we discuss the potential of future sky surveys. We argue that photometric redshifts have too large errors, i.e. PanSTARRS and LSST cannot be used. Conversely, the EUCLID project will not cover the relevant redshift regime. We also discuss the potentials and problems of front-edge classifications of galaxy discs in order to improve the autocorrelation estimates of angular-momentum orientation.

  2. Star-disc interaction in galactic nuclei: formation of a central stellar disc

    Science.gov (United States)

    Panamarev, Taras; Shukirgaliyev, Bekdaulet; Meiron, Yohai; Berczik, Peter; Just, Andreas; Spurzem, Rainer; Omarov, Chingis; Vilkoviskij, Emmanuil

    2018-05-01

    We perform high-resolution direct N-body simulations to study the effect of an accretion disc on stellar dynamics in an active galactic nucleus (AGN). We show that the interaction of the nuclear stellar cluster (NSC) with the gaseous accretion disc (AD) leads to formation of a stellar disc in the central part of the NSC. The accretion of stars from the stellar disc on to the super-massive black hole is balanced by the capture of stars from the NSC into the stellar disc, yielding a stationary density profile. We derive the migration time through the AD to be 3 per cent of the half-mass relaxation time of the NSC. The mass and size of the stellar disc are 0.7 per cent of the mass and 5 per cent of the influence radius of the super-massive black hole. An AD lifetime shorter than the migration time would result in a less massive nuclear stellar disc. The detection of such a stellar disc could point to past activity of the hosting galactic nucleus.

  3. Essential math and calculations for pharmacy technicians

    CERN Document Server

    Reddy, Indra K

    2003-01-01

    Working with Roman and Arabic NumeralsUsing Fractions and Decimals in Pharmacy MathUsing Ratios, Proportions and Percentages in Dosage CalculationsApplying Systems of MeasurementsInterpreting Medication OrdersIdentifying Prescription Errors and OmissionsWorking with Liquid Dosage FormsWorking with Solid Dosage FormsAdjusting IsotonicityWorking with Buffer and Ionization ValuesDealing with ReconstitutionsDetermining Milliequivalent StrengthsCalculating Caloric Values Determining IV Flow RatesWorking with Insulin and Heparin ProductsAppendices: A: Working with Temperature ConversionsB: Working with Capsule Dosage FormsC: Dealing with Pediatric Dosages D: Understanding Essential Business Math.

  4. The "Parrot Math" Attack on Memorization

    Directory of Open Access Journals (Sweden)

    Bill Quirk

    2013-01-01

    Full Text Available Constructivist math educators regularly cite Parrot Math by Thomas C. O'Brien. Although this paper promotes constructivist "activity-based" learning over direct instruction, it's primary claim to fame is the open hostility to memorization. Professor O'Brien rejects "memorization and parrot-like drill " in favor of "children's invented strategies." He references a paper by Kamii and Dominick as evidence of "considerable research" showing that mastery of the standard algorithms of arithmetic is harmful for children. [See The Bogus Research in Kamii and Dominick's Harmful Algorithms Papers

  5. Strategies for Reducing Math Anxiety. Information Capsule. Volume 1102

    Science.gov (United States)

    Blazer, Christie

    2011-01-01

    Approximately 93 percent of Americans indicate that they experience some level of math anxiety. Math anxiety is defined as negative emotions that interfere with the solving of mathematical problems. Studies have found that some students who perform poorly on math assessments actually have a full understanding of the concepts being tested; however,…

  6. Supporting English Language Learners in Math Class, Grades K-2

    Science.gov (United States)

    Bresser, Rusty; Melanese, Kathy; Sphar, Christine

    2009-01-01

    More than 10 percent of the students in our nation's public schools are English language learners, and this number grows each year. Many of these students are falling behind in math. "Supporting English Language Learners in Math Class, Grades K-2" outlines the challenges ELL students face when learning math and provides a wealth of specific…

  7. Firefighter Math - a web-based learning tool

    Science.gov (United States)

    Dan Jimenez

    2010-01-01

    Firefighter Math is a web based interactive resource that was developed to help prepare wildland fire personnel for math based training courses. The website can also be used as a refresher for fire calculations including slope, flame length, relative humidity, flow rates, unit conversion, etc. The website is designed to start with basic math refresher skills and...

  8. Specific Cognitive Predictors of Early Math Problem Solving

    Science.gov (United States)

    Decker, Scott L.; Roberts, Alycia M.

    2015-01-01

    Development of early math skill depends on a prerequisite level of cognitive development. Identification of specific cognitive skills that are important for math development may not only inform instructional approaches but also inform assessment approaches to identifying children with specific learning problems in math. This study investigated the…

  9. Mathematizing: An Emergent Math Curriculum Approach for Young Children

    Science.gov (United States)

    Rosales, Allen C.

    2015-01-01

    Based on years of research with early childhood teachers, author Allen Rosales provides an approach to create an emergent math curriculum that integrates children's interests with math concepts. The mathematizing approach is different from traditional math curriculums, as it immerses children in a process that is designed to develop their…

  10. Learning to Be a Math Teacher: What Knowledge Is Essential?

    Science.gov (United States)

    Reid, Mary; Reid, Steven

    2017-01-01

    This study critically examined the math content knowledge (MCK) of teacher candidates (TCs) enrolled in a two-year Master of Teaching (MT) degree. Teachers require a solid math knowledge base in order to support students' achievement. Provincial and international math assessments have been of major concern in Ontario, Canada, due to declining…

  11. Formula for Success: Engaging Families in Early Math Learning

    Science.gov (United States)

    Global Family Research Project, 2017

    2017-01-01

    Early math ability is one of the best predictors of children's later success in school. Because children's learning begins in the home, families are fundamental in shaping children's interest and skills in math. The experience of learning and doing math, however, looks different from the instruction that was offered when most adults were in…

  12. How to Make the Most of Math Manipulatives.

    Science.gov (United States)

    Burns, Marilyn

    1996-01-01

    A discussion of how to use math manipulatives to teach elementary students focuses on essential program elements: what math manipulatives are and why they are used, common questions about math manipulatives, how one teacher introduced the geoboard into the classroom, and pattern block activities. (SM)

  13. District Finds the Right Equation to Improve Math Instruction

    Science.gov (United States)

    Holmstrom, Annette

    2010-01-01

    The math problem is common to most U.S. school districts, and education leaders are well aware that U.S. math achievement lags far behind many other countries in the world. University Place (Washington) School District Superintendent Patti Banks found the conspicuous income gap for math scores even more disturbing. In her school district, only 23%…

  14. Impact of Math Snacks Games on Students' Conceptual Understanding

    Science.gov (United States)

    Winburg, Karin; Chamberlain, Barbara; Valdez, Alfred; Trujillo, Karen; Stanford, Theodore B.

    2016-01-01

    This "Math Snacks" intervention measured 741 fifth grade students' gains in conceptual understanding of core math concepts after game-based learning activities. Teachers integrated four "Math Snacks" games and related activities into instruction on ratios, coordinate plane, number systems, fractions and decimals. Using a…

  15. Radiological assessment of loss of disc height during acute and chronic degenerative lumbar disc alterations

    International Nuclear Information System (INIS)

    Zoellner, J.; Sancaktaroglu, T.; Nafe, B.; Eysel, P.; Loew, R.

    2001-01-01

    Aim of the study: A loss of disc height with increasing segmental mobility is an important reason for low back pain. The measurement of hyaluronic acid content of the nucleus pulposus prolaps shows a difference between acute (group 1) and chronic (group 2) disc degeneration. The purpose of the present investigation was to determine the decreasing of disc height between these two groups and the no-symptomatic segments of these patients. Methods: 20 human lateral preoperative X-ray measurements according to Frobin et al. were taken; group 1 with 7 patients (mean age 41 years) and group 2 with 13 patients (mean age 44 years). Results: There was a significant tendency (p=0.091) to a reduction of disc height in group 2 between symptomatic and asymptomatic discs. Conclusion: The used method is not suitable to answer the present question conclusively. (orig.) [de

  16. The Sum of All Fears: The Effects of Math Anxiety on Math Achievement in Fifth Grade Students and the Implications for School Counselors

    Science.gov (United States)

    Ruff, Sarah E.; Boes, Susan R.

    2014-01-01

    Low math achievement is a recurring weakness in many students. Math anxiety is a persistent and significant theme to math avoidance and low achievement. Causes for math anxiety include social, cognitive, and academic factors. Interventions to reduce math anxiety are limited as they exclude the expert skills of professional school counselors to…

  17. DZ Chamaeleontis: a bona fide photoevaporating disc

    Science.gov (United States)

    Canovas, H.; Montesinos, B.; Schreiber, M. R.; Cieza, L. A.; Eiroa, C.; Meeus, G.; de Boer, J.; Ménard, F.; Wahhaj, Z.; Riviere-Marichalar, P.; Olofsson, J.; Garufi, A.; Rebollido, I.; van Holstein, R. G.; Caceres, C.; Hardy, A.; Villaver, E.

    2018-02-01

    Context. DZ Cha is a weak-lined T Tauri star (WTTS) surrounded by a bright protoplanetary disc with evidence of inner disc clearing. Its narrow Hα line and infrared spectral energy distribution suggest that DZ Cha may be a photoevaporating disc. Aims: We aim to analyse the DZ Cha star + disc system to identify the mechanism driving the evolution of this object. Methods: We have analysed three epochs of high resolution optical spectroscopy, photometry from the UV up to the sub-mm regime, infrared spectroscopy, and J-band imaging polarimetry observations of DZ Cha. Results: Combining our analysis with previous studies we find no signatures of accretion in the Hα line profile in nine epochs covering a time baseline of 20 yr. The optical spectra are dominated by chromospheric emission lines, but they also show emission from the forbidden lines [SII] 4068 and [OI] 6300Å that indicate a disc outflow. The polarized images reveal a dust depleted cavity of 7 au in radius and two spiral-like features, and we derive a disc dust mass limit of Mdust 80 MJup) companions are detected down to 0.̋07 ( 8 au, projected). Conclusions: The negligible accretion rate, small cavity, and forbidden line emission strongly suggests that DZ Cha is currently at the initial stages of disc clearing by photoevaporation. At this point the inner disc has drained and the inner wall of the truncated outer disc is directly exposed to the stellar radiation. We argue that other mechanisms like planet formation or binarity cannot explain the observed properties of DZ Cha. The scarcity of objects like this one is in line with the dispersal timescale (≲105 yr) predicted by this theory. DZ Cha is therefore an ideal target to study the initial stages of photoevaporation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 097.C-0536. Based on data obtained from the ESO Science Archive Facility under request number 250112.

  18. INJURIES IN DISC GOLF - A DESCRIPTIVE CROSS-SECTIONAL STUDY

    DEFF Research Database (Denmark)

    Rahbek, Martin Amadeus; Nielsen, Rasmus Oestergaard

    2016-01-01

    BACKGROUND: Disc golf is rapidly increasing in popularity and more than two million people are estimated to regularly participate in disc golf activities. Despite this popularity, the epidemiology of injuries in disc golf remains under reported. PURPOSE: The purpose of the present study...... was to investigate the prevalence and anatomic distribution of injuries acquired through disc-golf participation in Danish disc golf players. METHODS: The study was a cross-sectional study conducted on Danish disc-golf players. In May 2015, invitations to complete a web-based questionnaire were spread online via...... social media, and around disc-golf courses in Denmark. The questionnaire included questions regarding disc-golf participation and the characteristics of injuries acquired through disc golf participation. The data was analyzed descriptively. RESULTS: An injury prevalence of 13.3% (95% CI: 6.7% to 19...

  19. MRI findings of traumatic cervical disc herniation

    International Nuclear Information System (INIS)

    Tanaka, Hisato; Kasahara, Takaki; Akiyama, Nanae

    2011-01-01

    In general practice, disc hernia is increasingly being questioned about its relation with traffic injuries. In this study, we examined the image findings of cervical disc herniation for findings indicative of traumatic hernia. In 2008, we examined 35 cases of cervical disc herniation at our hospital by MRI. The patients were divided into two groups; patients with trauma history (19 cases) and those without (16 cases), and their images were compared. Disc herniation in the trauma group showed high intensity at T2, with some of the patients in this group also indicating continuous high intensity of the internal and herniated discs. Traumatic force was found to cause swelling under the laryngeal soft tissue. Cases with further flexion injury showed interspinous ligament hemorrhage. These findings strongly suggest the involvement of injury. But given that some younger patients in the non-trauma group also show high intensity at T2*, attention must be paid not to confuse swelling below the larynx with inflammation of the longus colli muscle. (author)

  20. Active galactic nucleus outflows in galaxy discs

    Science.gov (United States)

    Hartwig, Tilman; Volonteri, Marta; Dashyan, Gohar

    2018-05-01

    Galactic outflows, driven by active galactic nuclei (AGNs), play a crucial role in galaxy formation and in the self-regulated growth of supermassive black holes (BHs). AGN feedback couples to and affects gas, rather than stars, and in many, if not most, gas-rich galaxies cold gas is rotationally supported and settles in a disc. We present a 2D analytical model for AGN-driven outflows in a gaseous disc and demonstrate the main improvements, compared to existing 1D solutions. We find significant differences for the outflow dynamics and wind efficiency. The outflow is energy-driven due to inefficient cooling up to a certain AGN luminosity (˜1043 erg s-1 in our fiducial model), above which the outflow remains momentum-driven in the disc up to galactic scales. We reproduce results of 3D simulations that gas is preferentially ejected perpendicular to the disc and find that the fraction of ejected interstellar medium is lower than in 1D models. The recovery time of gas in the disc, defined as the free-fall time from the radius to which the AGN pushes the ISM at most, is remarkably short, of the order 1 Myr. This indicates that AGN-driven winds cannot suppress BH growth for long. Without the inclusion of supernova feedback, we find a scaling of the BH mass with the halo velocity dispersion of MBH ∝ σ4.8.

  1. Math practice and its influence on math skills and executive functions in adolescents with mild to borderline intellectual disability

    NARCIS (Netherlands)

    Jansen, B.R.J.; Lange, E.; van der Molen, M.J.

    2013-01-01

    Adolescents with mild to borderline intellectual disability (MBID) often complete schooling without mastering basic math skills, even though basic math is essential for math-related challenges in everyday life. Limited attention to cognitive skills and low executive functioning (EF) may cause this

  2. Opportunities for Learning Math in Elementary School: Implications for SES Disparities in Procedural and Conceptual Math Skills

    Science.gov (United States)

    Bachman, Heather J.; Votruba-Drzal, Elizabeth; El Nokali, Nermeen E.; Castle Heatly, Melissa

    2015-01-01

    The present study examined whether multiple opportunities to learn math were associated with smaller socioeconomic status (SES) disparities in fifth-grade math achievement using data from the NICHD Study of Early Child Care and Youth Development (SECCYD; N = 1,364). High amounts of procedural math instruction were associated with higher…

  3. Developmental Math Programs in California Community College: An Analysis of Math Boot Camp at Cosumnes River College

    Science.gov (United States)

    Powell, Torence J.

    2017-01-01

    The California Community College system, as an open access institution, is tasked with helping students who possess math skills far below college-level complete math course requirements for obtaining an associate degree or transfer to a university. Colleges have created various developmental math programs to achieve this mission; this paper…

  4. Order of Administration of Math and Verbal Tests: An Ecological Intervention to Reduce Stereotype Threat on Girls' Math Performance

    Science.gov (United States)

    Smeding, Annique; Dumas, Florence; Loose, Florence; Régner, Isabelle

    2013-01-01

    In 2 field experiments, we relied on the very features of real testing situations--where both math and verbal tests are administered--to examine whether order of test administration can, by itself, create vs. alleviate stereotype threat (ST) effects on girls' math performance. We predicted that taking the math test before the verbal test would be…

  5. Effects of Math Anxiety and Perfectionism on Timed versus Untimed Math Testing in Mathematically Gifted Sixth Graders

    Science.gov (United States)

    Tsui, Joanne M.; Mazzocco, Michele M. M.

    2006-01-01

    This study was designed to examine the effects of math anxiety and perfectionism on math performance, under timed testing conditions, among mathematically gifted sixth graders. We found that participants had worse math performance during timed versus untimed testing, but this difference was statistically significant only when the timed condition…

  6. Jamming Transition: Heptagons, Pentagons, and Discs

    Directory of Open Access Journals (Sweden)

    Xu Yuanyuan

    2017-01-01

    Full Text Available The jamming behavior of a system composed of discs has been well documented. However, it remains unclear how a granular system consisting of non-spherical particles transitions between unjammed and jammed states. Here, we present compression experiments to study the jamming transition of 2D granular materials composed of photoelastic heptagonal particles and compare these results to data for discs and pentagons. We determine the critical packing fraction of heptagons and make a comparison to discs and pentagons. In the experiment, we subject 618 heptagonal particles to cyclic compression. We track the motion (inlcuding rotations of the particles, and we measure forces on particles by photoelasticity. We observe a power law relationship between the average contact number (Z and the pressure (P. Furthermore, we classify the type of contacts by the relative orientation of pairs of contacting particles (creating point-to-face and face-to-face contacts, and we explore the evolution of the contacts during jamming.

  7. On the formation of exponential discs

    International Nuclear Information System (INIS)

    Yoshii, Yuzuru; Sommer-Larsen, Jesper

    1989-01-01

    Spiral galaxy discs are characterized by approximately exponential surface luminosity profiles. In this paper the evolutionary equations for a star-forming, viscous disc are solved analytically or semi-analytically. It is shown that approximately exponential stellar surface density profiles result if the viscous time-scale t ν is comparable to the star-formation time scale t * everywhere in the disc. The analytical solutions are used to illuminate further on the issue of why the above mechanism leads to resulting exponential stellar profiles under certain conditions. The sensitivity of the solution to variations of various parameters are investigated and show that the initial gas surface density distribution has to be fairly regular in order that final exponential stellar surface density profiles result. (author)

  8. Optic disc pit with sectorial retinitis pigmentosa.

    Science.gov (United States)

    Balikoglu-Yilmaz, Melike; Taskapili, Muhittin; Yilmaz, Tolga; Teke, Mehmet Yasin

    2013-01-01

    Sectorial retinitis pigmentosa (RP) and optic disc pit (ODP) are rare clinical conditions. We present a 40-year-old woman with a history of mild night blindness and decreased vision in the right eye for about 5 years. Fundus examination revealed retinal pigmentary changes in the superior and inferotemporal sectors covering the macula and reduced arterial calibre and ODP at the temporal edge of the optic disc. In addition, fundus autofluorescence, spectral-domain optical coherence tomography, fluorescein angiography, and multifocal electroretinogram scans confirmed these clinical findings. Visual acuity was decreased due to an atrophic-appearing foveal lesion. No intervention was suggested because of the poor visual potential. To the best of our knowledge, the present study is the first to describe coexistent optic disc pit and sectorial RP in the superior and inferotemporal sectors covering the macula in the same eye with figures.

  9. Optic Disc Pit with Sectorial Retinitis Pigmentosa

    Directory of Open Access Journals (Sweden)

    Melike Balikoglu-Yilmaz

    2013-01-01

    Full Text Available Sectorial retinitis pigmentosa (RP and optic disc pit (ODP are rare clinical conditions. We present a 40-year-old woman with a history of mild night blindness and decreased vision in the right eye for about 5 years. Fundus examination revealed retinal pigmentary changes in the superior and inferotemporal sectors covering the macula and reduced arterial calibre and ODP at the temporal edge of the optic disc. In addition, fundus autofluorescence, spectral-domain optical coherence tomography, fluorescein angiography, and multifocal electroretinogram scans confirmed these clinical findings. Visual acuity was decreased due to an atrophic-appearing foveal lesion. No intervention was suggested because of the poor visual potential. To the best of our knowledge, the present study is the first to describe coexistent optic disc pit and sectorial RP in the superior and inferotemporal sectors covering the macula in the same eye with figures.

  10. Imaging cell competition in Drosophila imaginal discs.

    Science.gov (United States)

    Ohsawa, Shizue; Sugimura, Kaoru; Takino, Kyoko; Igaki, Tatsushi

    2012-01-01

    Cell competition is a process in which cells with higher fitness ("winners") survive and proliferate at the expense of less fit neighbors ("losers"). It has been suggested that cell competition is involved in a variety of biological processes such as organ size control, tissue homeostasis, cancer progression, and the maintenance of stem cell population. By advent of a genetic mosaic technique, which enables to generate fluorescently marked somatic clones in Drosophila imaginal discs, recent studies have presented some aspects of molecular mechanisms underlying cell competition. Now, with a live-imaging technique using ex vivo-cultured imaginal discs, we can dissect the spatiotemporal nature of competitive cell behaviors within multicellular communities. Here, we describe procedures and tips for live imaging of cell competition in Drosophila imaginal discs. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. M6-C artificial disc placement.

    Science.gov (United States)

    Coric, Domagoj; Parish, John; Boltes, Margaret O

    2017-01-01

    There has been a steady evolution of cervical total disc replacement (TDR) devices over the last decade resulting in surgical technique that closely mimics anterior cervical discectomy and fusion as well as disc design that emphasizes quality of motion. The M6-C TDR device is a modern-generation artificial disc composed of titanium endplates with tri-keel fixation as well as a polyethylene weave with a polyurethane core. Although not yet approved by the FDA, M6-C has finished a pilot and pivotal US Investigational Device Exemption (IDE) study. The authors present the surgical technique for implantation of a 2-level M6-C cervical TDR device. The video can be found here: https://youtu.be/rFEAqINLRCo .

  12. Calcification of intervertebral discs in children

    International Nuclear Information System (INIS)

    Hoermann, D.

    1984-01-01

    Thirteen children with intervertebral disc calcifications of the cervical, thoracal and lumbar spine have been diagnosed since 1970. Most of them were observed over a period of several years. Ten children fell ill with acute pains, but only 2 of them sufferred from a trauma. In 3 cases the features were discovered accidentally combined with malformations of vertebral bodies and congenital diseases. Our results suggest a primary structural inferiority of the calcified discs. The calcifications arise partially from a birth trauma, partially from an unknown etiology. They can last for a long time without symptoms. An acute event effects the pains due to shifting or herniation of calcified disc-fragments. Secondary findings such as decrease of the height of cervical vertebral bodies or destructions of the endplates of thoracal and lumbar vertebral bodies disappear retarded and often incompletely and demand a control for a long time. (orig.)

  13. Interactive geometry inside MathDox

    NARCIS (Netherlands)

    Cuypers, H.; Hendriks, M.; Knopper, J.W.

    2010-01-01

    In this paper we describe how we envision using interactive geometry inside MathDox pages. In particular, by some examples we discuss how users and mathematical services (offered by various mathematical software packages) can interact with the geometric objects available. This not only includes

  14. What Adds Up?: Math Enrollment and Graduation

    Science.gov (United States)

    Utah System of Higher Education, 2015

    2015-01-01

    College students struggling to pass a college level math course required for Quantitative Literacy (QL) credit1 has been a common issue facing many institutions in higher education. In the fall of 2014, the Utah State Board of Regents solidified a statewide initiative that set goals for each of the Utah System of Higher Education institutions (UU,…

  15. ADP Security Plan, Math Building, Room 1139

    Energy Technology Data Exchange (ETDEWEB)

    Melton, R.

    1985-08-27

    This document provides the draft copy of an updated (ADP) Security Plan for an IBM Personal Computer to be used in the Math Building at PNL for classified data base management. Using the equipment specified in this document and implementing the administrative and physical procedures as outlined will provide the secure environment necessary for this work to proceed.

  16. Admission Math Level and Student Performance

    DEFF Research Database (Denmark)

    la Cour, Lisbeth

    2015-01-01

    In this paper we analyze the study performance data for three cohorts of students for the course in Economics at the Business Diploma (herafter HD) study program at Copenhagen Business School. Out main findings are 1) that students with the lowest level of math from high school are performing worse...

  17. Confessions of a Dr Math tutor

    CSIR Research Space (South Africa)

    Butgereit, L

    2015-06-01

    Full Text Available Mathematics look different on a small 3-inch screen of an inexpensive cell phone when compared to a 3-meter whiteboard in a mathematics classroom. Dr Math uses cell phone or mobile data "chat" technologies to assist primary and secondary school...

  18. Early math intervention for marginalized students

    DEFF Research Database (Denmark)

    Overgaard, Steffen; Tonnesen, Pia Beck

    2016-01-01

    This study is one of more substudies in the project Early Math Intervention for Marginalized Students (TMTM2014). The paper presents the initial process of this substudy that will be carried out fall 2015. In the TMTM2014 project, 80 teachers, who completed a one week course in the idea of TMTM...

  19. Fold in Origami and Unfold Math

    Science.gov (United States)

    Georgeson, Joseph

    2011-01-01

    Students enjoy origami and like making everything from paper cranes to footballs out of small, colorful squares of paper. They can invent their own shapes and are intrigued by the polyhedrons that they can construct. Paper folding is fun, but where is the math? Unless teachers develop lessons that address mathematical objectives, origami could be…

  20. Math on the Job. Metal Product Assembler.

    Science.gov (United States)

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This booklet is intended to help mainstreamed mentally retarded, emotionally disturbed, or learning disabled high school students acquire a basic understanding of the responsibilities and working conditions of metal product assemblers and to practice basic math skills necessary in the occupation. The first section provides a brief introduction to…

  1. Ideas on Manipulative Math for Young Children.

    Science.gov (United States)

    Murray, Anne

    2001-01-01

    Presents a case study of one kindergarten class in which the mathematics center is the popular area in the room. Focuses on how math is best understood if activities follow the five-C formula: collaborative, concrete, comprehensive, connecting, and cavorting. Describes how children used manipulatives to construct mathematics concepts…

  2. The Demise of the Asian Math Gene.

    Science.gov (United States)

    Bracey, Gerald W.

    1999-01-01

    The 1996 National Assessment of Educational Progress math scores for eighth-graders show that when socioeconomic status is considered, English-proficient Asian students have no achievement advantage over other ethnic groups. However, Chinese sixth-graders, using abstract reasoning skills, outperformed American students on 12 open-ended math…

  3. MIT professor wins major international math prize

    CERN Multimedia

    Allen, S

    2004-01-01

    Mathematicians Isadore Singer of MIT and Sir Michael Francis Atiyah of the University of Edinburgh will share an $875,000 award as winners of the second Abel Prize, which some hope will come to be seen as a Nobel Prize for math.

  4. Online Options for Math-Advanced Students

    Science.gov (United States)

    Wessling, Suki

    2012-01-01

    Once upon a time, a student well advanced past grade level in math would have had few choices. Advanced students would invariably outpace the skills of their elementary teachers, and due to age wouldn't have options such as going to the middle school or community college for classes. Soon thereafter, students would enter middle school only to find…

  5. Relationship between Affective Dimension and Math Learning

    Directory of Open Access Journals (Sweden)

    Ronny Gamboa Araya

    2014-05-01

    Full Text Available Math has become an obstacle to achieve educational goals for a large number of students; thus it has transcended the academic world and has become a cognitive and emotional impairment.  What students feel, perceive, believe, and how they act directly influences this.  In addition, what teachers feel and perceive, their expectations, beliefs and attitudes towards the discipline also play an important role in how they teach and in the affective dimension of their students.  Based on theoretical aspects from various authors, this paper is aimed at addressing some elements regarding the affective dimension, and at showing elements pertaining to teachers and students, and their relationship with math learning and teaching.  It was concluded that the role of the affective dimension in math learning must be addressed by math educators in order to understand the process from the perspective of the actors associated with it, both students and teachers, as well as to achieve a change in the discipline by improving the beliefs and attitudes of students and teachers.

  6. New Mexico Math Pathways Taskforce Report

    Science.gov (United States)

    New Mexico Higher Education Department, 2016

    2016-01-01

    In April 2015 New Mexico faculty, Dana Center staff, and New Mexico Higher Education (NMHED) co-presented the need for better math pathways statewide. Faculty from 6 institutions (New Mexico State University, New Mexico Highlands University, Dine College, Eastern New Mexico University, El Paso Community College, and San Juan College) participated…

  7. Tic Tac Toe Math. Train the Trainer.

    Science.gov (United States)

    Center for Alternative Learning, Bryn Mawr, PA.

    This report describes a project that developed a "Train the Trainer" program that would enable individuals to learn and teach the alternative instructional technique, Tic Tac Toe Math, developed by Richard Cooper for adult basic education students. The pilot workshop conducted as part of the project identified problems that traditional…

  8. Basic math and pre-algebra practice problems for dummies

    CERN Document Server

    Zegarelli, Mark

    2013-01-01

    1001 Basic Math & Pre- Algebra Practice Problems For  Dummies   Practice makes perfect-and helps deepen your understanding of basic math and pre-algebra 1001 Basic Math & Pre-Algebra Practice Problems For Dummies, with free access to online practice problems, takes you beyond the instruction and guidance offered in Basic Math & Pre-Algebra For Dummies, giving you 1,001 opportunities to practice solving problems from the major topics in your math course. You begin with some basic arithmetic practice, move on to fractions, decimals, and per

  9. Avoiding math on a rapid timescale: Emotional responsivity and anxious attention in math anxiety.

    Science.gov (United States)

    Pizzie, Rachel G; Kraemer, David J M

    2017-11-01

    Math anxiety (MA) is characterized by negative feelings towards mathematics, resulting in avoidance of math classes and of careers that rely on mathematical skills. Focused on a long timescale, this research may miss important cognitive and affective processes that operate moment-to-moment, changing rapid reactions even when a student simply sees a math problem. Here, using fMRI with an attentional deployment paradigm, we show that MA influences rapid spontaneous emotional and attentional responses to mathematical stimuli upon brief presentation. Critically, participants viewed but did not attempt to solve the problems. Indicating increased threat reactivity to even brief presentations of math problems, increased MA was associated with increased amygdala response during math viewing trials. Functionally and anatomically defined amygdala ROIs yielded similar results, indicating robustness of the finding. Similar to the pattern of vigilance and avoidance observed in specific phobia, behavioral results of the attentional paradigm demonstrated that MA is associated with attentional disengagement for mathematical symbols. This attentional avoidance is specific to math stimuli; when viewing negatively-valenced images, MA is correlated with attentional engagement, similar to other forms of anxiety. These results indicate that even brief exposure to mathematics triggers a neural response related to threat avoidance in highly MA individuals. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Appearance of Keplerian discs orbiting Kerr superspinars

    Energy Technology Data Exchange (ETDEWEB)

    Stuchlik, Zdenek; Schee, Jan, E-mail: zdenek.stuchlik@fpf.slu.c, E-mail: jan.schee@fpf.slu.c [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo nam. 13, Opava (Czech Republic)

    2010-11-07

    We study optical phenomena related to the appearance of Keplerian accretion discs orbiting Kerr superspinars predicted by string theory. The superspinar exterior is described by standard Kerr naked singularity geometry breaking the black hole limit on the internal angular momentum (spin). We construct local photon escape cones for a variety of orbiting sources that enable us to determine the superspinars silhouette in the case of distant observers. We show that the superspinar silhouette depends strongly on the assumed edge where the external Kerr spacetime is joined to the internal spacetime governed by string theory and significantly differs from the black hole silhouette. The appearance of the accretion disc is strongly dependent on the value of the superspinar spin in both their shape and frequency shift profile. Apparent extension of the disc grows significantly with the growing spin, while the frequency shift grows with the descending spin. This behaviour differs substantially from the appearance of discs orbiting black holes enabling thus, at least in principle, to distinguish clearly the Kerr superspinars and black holes. In vicinity of a Kerr superspinar the non-escaped photons have to be separated to those captured by the superspinar and those being trapped in its strong gravitational field leading to self-illumination of the disc that could even influence its structure and cause self-reflection effect of radiation of the disc. The amount of trapped photons grows with descending superspinar spin. We thus can expect significant self-illumination effects in the field of Kerr superspinars with near-extreme spin a {approx} 1.

  11. Actuator disc edge singularity. The key to a revised actuator disc concept and momentum theory

    Energy Technology Data Exchange (ETDEWEB)

    Kuik, G.A.M. van (The Wind Energy Group of the Technical University Eindhoven (NL))

    1989-01-01

    Since the beginning of rotor aerodynamics the actuator disc momentum theory occupies a prominant place in almost any textbook on this subject. Specially in axial flow the theory provides an easy and rather accurate performance prediction. The results first obtained by Lanchester for the induced power of a hovering rotor and the maximum power of a wind turbine are still used as guidelines for complicated calculations. On the other hand, experimental results for propellers are known to deviate systematically (some 10%) from the momentum theory results. This is commonly attributed to the differences between a real rotor and an actuator disc. However, some actuator disc- and actuator strip (the 2-dimensional version) experiments are described in literature, showing the same deviations from momentum theory results. Therefore, apart from the question how representative an actuator disc is for a real rotor, the actuator disc concept itself may be inadequate. This problem is the subject of the work describe here. It will be shown that the classical actuator disc concept ignores discrete forces resulting from a flow singularity at the edge of the disc. The (extended) momentum theory, applied to this actuator strip model, shows a shift of the results towards the experimental data, and for the static case (hover) even a quantitative agreement is obtained. (author) 12 refs.

  12. Disc valve for sampling erosive process streams

    Science.gov (United States)

    Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.

    1986-01-07

    A four-port disc valve is described for sampling erosive, high temperature process streams. A rotatable disc defining opposed first and second sampling cavities rotates between fired faceplates defining flow passageways positioned to be alternatively in axial alignment with the first and second cavities. Silicon carbide inserts and liners composed of [alpha] silicon carbide are provided in the faceplates and in the sampling cavities to limit erosion while providing lubricity for a smooth and precise operation when used under harsh process conditions. 1 fig.

  13. Static axisymmetric discs and gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Chamorro, A.; Gregory, R.; Stewart, J.M.

    1987-09-08

    Regular static axisymmetric vacuum solutions of Einstein's field equations representing the exterior field of a finite thin disc are found. These are used to describe the slow collapse of a disc-like object. If no conditions are placed on the matter, a naked singularity is formed and the cosmic censorship hypothesis would be violated. Imposition of the weak energy condition, however, prevents slow collapse to a singularity and preserves the validity of this hypothesis. The validity of the hoop conjecture is also discussed.

  14. Cells and Biomaterials for Intervertebral Disc Regeneration

    CERN Document Server

    Grad, Sibylle

    2010-01-01

    Disorders related to the intervertebral disc (IVD) are common causes of morbidity and of severe life quality deterioration. IVD degeneration, although in many cases asymptomatic, is often the origin of painful neck and back diseases. In Western societies IVD related pain and disability account for enormous health care costs as a result of work absenteeism and thus lost production, disability benefits, medical and insurance expenses. Although only a small percentage of patients with disc disorders finally will undergo surgery, spinal surgery has been one of the fastest growing disciplines in th

  15. Neural correlates of math anxiety – an overview and implications

    Science.gov (United States)

    Artemenko, Christina; Daroczy, Gabriella; Nuerk, Hans-Christoph

    2015-01-01

    Math anxiety is a common phenomenon which can have a negative impact on numerical and arithmetic performance. However, so far little is known about the underlying neurocognitive mechanisms. This mini review provides an overview of studies investigating the neural correlates of math anxiety which provide several hints regarding its influence on math performance: while behavioral studies mostly observe an influence of math anxiety on difficult math tasks, neurophysiological studies show that processing efficiency is already affected in basic number processing. Overall, the neurocognitive literature suggests that (i) math anxiety elicits emotion- and pain-related activation during and before math activities, (ii) that the negative emotional response to math anxiety impairs processing efficiency, and (iii) that math deficits triggered by math anxiety may be compensated for by modulating the cognitive control or emotional regulation network. However, activation differs strongly between studies, depending on tasks, paradigms, and samples. We conclude that neural correlates can help to understand and explore the processes underlying math anxiety, but the data are not very consistent yet. PMID:26388824

  16. Neural correlates of math anxiety - an overview and implications.

    Science.gov (United States)

    Artemenko, Christina; Daroczy, Gabriella; Nuerk, Hans-Christoph

    2015-01-01

    Math anxiety is a common phenomenon which can have a negative impact on numerical and arithmetic performance. However, so far little is known about the underlying neurocognitive mechanisms. This mini review provides an overview of studies investigating the neural correlates of math anxiety which provide several hints regarding its influence on math performance: while behavioral studies mostly observe an influence of math anxiety on difficult math tasks, neurophysiological studies show that processing efficiency is already affected in basic number processing. Overall, the neurocognitive literature suggests that (i) math anxiety elicits emotion- and pain-related activation during and before math activities, (ii) that the negative emotional response to math anxiety impairs processing efficiency, and (iii) that math deficits triggered by math anxiety may be compensated for by modulating the cognitive control or emotional regulation network. However, activation differs strongly between studies, depending on tasks, paradigms, and samples. We conclude that neural correlates can help to understand and explore the processes underlying math anxiety, but the data are not very consistent yet.

  17. Neural correlates of math anxiety – An overview and implications

    Directory of Open Access Journals (Sweden)

    Christina eArtemenko

    2015-09-01

    Full Text Available Math anxiety is a common phenomenon which can have a negative impact on numerical and arithmetic performance. However, so far little is known about the underlying neurocognitive mechanisms. This mini review provides an overview of studies investigating the neural correlates of math anxiety which provide several hints regarding its influence on math performance: while behavioral studies mostly observe an influence of math anxiety on difficult math tasks, neurophysiological studies show that processing efficiency is already affected in basic number processing. Overall, the neurocognitive literature suggests that (i math anxiety elicits emotion- and pain-related activation during and before math activities, (ii that the negative emotional response to math anxiety impairs processing efficiency, and (iii that math deficits triggered by math anxiety may be compensated for by modulating the cognitive control or emotional regulation network. However, activation differs strongly between studies, depending on tasks, paradigms and samples. We conclude that neural correlates can help to understand and explore the processes underlying math anxiety, but the data are not very consistent yet.

  18. Effects of Math Anxiety and Perfectionism on Timed versus Untimed Math Testing in Mathematically Gifted Sixth Graders

    Science.gov (United States)

    Tsui, Joanne M.; Mazzocco, Michèle M. M.

    2009-01-01

    This study was designed to examine the effects of math anxiety and perfectionism on math performance, under timed testing conditions, among mathematically gifted sixth graders. We found that participants had worse math performance during timed versus untimed testing, but this difference was statistically significant only when the timed condition preceded the untimed condition. We also found that children with higher levels of either math anxiety or perfectionism had a smaller performance discrepancy during timed versus untimed testing, relative to children with lower levels of math anxiety or perfectionism. There were no statistically significant gender differences in overall test performance, nor in levels of math anxiety or perfectionism; however, the difference between performance on timed and untimed math testing was statistically significant for girls, but not for boys. Implications for educators are discussed. PMID:20084180

  19. Relationship of condylar position to disc position and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Incesu, L.; Taskaya-Yilmaz, N. E-mail: nergizy@omu.edu.tr; Oeguetcen-Toller, M.; Uzun, E

    2004-09-01

    Introduction/objective: The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position. Methods and material: One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging. Results and discussion: Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position. Conclusion: It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.

  20. Imaging characteristics of noncontained migrating disc fragment and cyst

    International Nuclear Information System (INIS)

    Eerens, I.; Demaerel, P.; Haven, F.; Wilms, G.; Loon, J. van; Calenbergh, F. van

    2001-01-01

    The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma. (orig.)

  1. Imaging characteristics of noncontained migrating disc fragment and cyst

    Energy Technology Data Exchange (ETDEWEB)

    Eerens, I.; Demaerel, P.; Haven, F.; Wilms, G. [Dept. of Radiology, University Hospitals, Leuven (Belgium); Loon, J. van; Calenbergh, F. van [Dept. of Neurosurgery, University Hospitals, Leuven (Belgium)

    2001-05-01

    The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma. (orig.)

  2. Solid angle subtended by two circular discs

    International Nuclear Information System (INIS)

    Gilly, Louis.

    1978-09-01

    Methods of calculation of solid angles, subtended by two circular discs are analysed. Calculus are methodically classified as follow: series development Legendre polynomes, defined integral, elliptic integrals, Bessel integrals, multiple integrals, Monte Carlo method, electrostatic analogy. Applications in Nuclear Physics are added as examples. List of numeric tables completes bibliography [fr

  3. Frictional Torque on a Rotating Disc

    Science.gov (United States)

    Mungan, Carl E.

    2012-01-01

    Resistance to motion often includes a dry frictional term independent of the speed of an object and a fluid drag term varying linearly with speed in the viscous limit. (At higher speeds, quadratic drag can also occur.) Here, measurements are performed for an aluminium disc mounted on bearings that is given an initial twist and allowed to spin…

  4. Fusion around cervical disc prosthesis: case report.

    NARCIS (Netherlands)

    Bartels, R.H.M.A.; Donk, R.

    2005-01-01

    OBJECTIVE AND IMPORTANCE: Cervical arthroplasty is a relatively new method to maintain motion after cervical anterior discectomy. Two cases are presented in which bony fusion occurred around a cervical disc prosthesis. CLINICAL PRESENTATION: A 30-year-old man and a 49-year-old woman underwent a

  5. Can Exercise Positively Influence the Intervertebral Disc?

    NARCIS (Netherlands)

    Belavý, Daniel L.; Albracht, Kirsten; Bruggemann, Gert Peter; Vergroesen, Pieter Paul A; van Dieën, Jaap H.

    2016-01-01

    To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a

  6. Radiographic identification of ingested disc batteries

    International Nuclear Information System (INIS)

    Maves, M.D.

    1986-01-01

    Recently, the hazards by posed the accidental ingestion and impaction of small disc batteries have been widely publicized in the medical and lay press. These foreign bodies, when lodged in the esophagus, leak a caustic solution of 26 to 45% sodium or potassium hydroxide which can cause a burn injury to the esophagus in a very short period of time. Because of the considerable clinical morbidity and mortality from this foreign body, it becomes imperative for the radiologist to quickly and accurately identify disc batteries on plain radiographs. This communication offers a series of radiologic signs important in the identification of disc batteries demonstrate a double density shadow due to the bilaminar structure of the battery. On lateral view, the edges of most disc batteries are round and again present a step-off at the junction of the cathode and anode. These findings are differentiated from the more common esophageal foreign body of a coin which does not have a double density on frontal projection, has a much sharper edge and no visible stepoff. (orig.)

  7. Kinematic structures in galactic disc simulations

    NARCIS (Netherlands)

    Roca-F� brega, S.; Romero-Gómez, M.; Figueras, F.; Antoja Castelltort, Teresa; Valenzuela, O.; Henney, W.J.; Torres-Peimbert, S.

    2011-01-01

    N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic

  8. Geršgorin discs revisited

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Hall, F.J.; Marsli, R.

    2013-01-01

    Roč. 438, č. 1 (2013), s. 598-603 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : geometric multiplicity * algebra ic multiplicity * Geršgorin disc Subject RIV: BA - General Mathematics Impact factor: 0.983, year: 2013

  9. Vascular complications of prosthetic inter-vertebral discs

    OpenAIRE

    Daly, Kevin J.; Ross, E. Raymond S.; Norris, Heather; McCollum, Charles N.

    2006-01-01

    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had e...

  10. Angiogenesis in the degeneration of the lumbar intervertebral disc

    OpenAIRE

    David, Gh; Ciurea, AV; Iencean, SM; Mohan, A

    2010-01-01

    The goal of the study is to show the histological and biochemical changes that indicate the angiogenesis of the intervertebral disc in lumbar intervertebral disc hernia and the existence of epidemiological correlations between these changes and the risk factors of lumbar intervertebral disc hernia, as well as the patient's quality of life (QOL). We have studied 50 patients aged between 18 and 73 years old, who have undergone lumbar intervertebral disc hernia surgery, making fibroblast growth ...

  11. On the diversity and statistical properties of protostellar discs

    Science.gov (United States)

    Bate, Matthew R.

    2018-04-01

    We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star-disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to ≈105 yr. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order 10 to a few hundred au, grow in size on time-scales ≲ 104 yr, and are smaller around lower mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Σ ∝ r-1. Disc to protostar mass ratios rarely exceed two, with a typical range of Md/M* = 0.1-1 to ages ≲ 104 yr and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.

  12. Physical Limitations to Tissue Engineering of Intervertabral Disc Cells

    OpenAIRE

    Kobayashi, Shigeru; Baba, Hisatoshi; Takeno, Kenichi; Miyazaki, Tsuyoshi; Meir, Adam; Urban, Jill

    2010-01-01

    There is increasing interest in the using biological methods to repair degenerate discs. Biological repair depends on the disc maintaining a population of viable and active cells. Adequate nutrition of the disc influences the outcome of such therapies and, hence, must be considered to be a crucial parameter. Therefore, it is very important to maintain an appropriate physicochemical environment to achieve successful disc repair by biological methods and tissue engineering procedures.

  13. Positional and morphologic changes of the temporomandibular joint disc using magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ahn, Hyoun Suk; Cho, Su Beom; Koh, Kwang Joon

    2001-01-01

    To evaluate displacement and morphologic changes of the temporomandibular joint (TMJ) disc in patient with internal derangement using magnetic resonance imaging (MRI). One hundred and forty five MR images of TMJs in 73 patients were evaluated. Positional and morphologic changes of the TMJ disc were assessed. Lateral or medial disc displacement was also evaluated on cornal images. Among 63 discs with anterior disc displacement, 37 discs were assessed as a biconcave disc and 21 as a deformed disc. Rotational disc displacement was observed in 35 disc. Anteromedial disc displacement was observed in 29 discs, and anterolateral direction in 6 discs. Among 35 rotational displacement, 5 biconcave discs and 21 deformed discs were observed. Rotational and sideways displacement of TMJ discs were found to be common and an important aspect of internal derangement. This study also suggests that sagittal and coronal images of the TMJ have complementary abilities for an assessment of joint abnormality

  14. Grain size segregation in debris discs

    Science.gov (United States)

    Thebault, P.; Kral, Q.; Augereau, J.-C.

    2014-01-01

    Context. In most debris discs, dust grain dynamics is strongly affected by stellar radiation pressure. Because this mechanism is size-dependent, we expect dust grains to be spatially segregated according to their sizes. However, because of the complex interplay between radiation pressure, grain processing by collisions, and dynamical perturbations, this spatial segregation of the particle size distribution (PSD) has proven difficult to investigate and quantify with numerical models. Aims: We propose to thoroughly investigate this problem by using a new-generation code that can handle some of the complex coupling between dynamical and collisional effects. We intend to explore how PSDs behave in both unperturbed discs at rest and in discs pertubed by planetary objects. Methods: We used the DyCoSS code to investigate the coupled effect of collisions, radiation pressure, and dynamical perturbations in systems that have reached a steady-state. We considered two setups: a narrow ring perturbed by an exterior planet, and an extended disc into which a planet is embedded. For both setups we considered an additional unperturbed case without a planet. We also investigated the effect of possible spatial size segregation on disc images at different wavelengths. Results: We find that PSDs are always spatially segregated. The only case for which the PSD follows a standard dn ∝ s-3.5ds law is for an unperturbed narrow ring, but only within the parent-body ring itself. For all other configurations, the size distributions can strongly depart from such power laws and have steep spatial gradients. As an example, the geometrical cross-section of the disc is very rarely dominated by the smallest grains on bound orbits, as it is expected to be in standard PSDs in sq with q ≤ -3. Although the exact profiles and spatial variations of PSDs are a complex function of the set-up that is considered, we are still able to derive some reliable results that will be useful for image or SED

  15. Prognosis of intervertebral disc loss from diagnosis of degenerative disc disease

    Science.gov (United States)

    Li, S.; Lin, A.; Tay, K.; Romano, W.; Osman, Said

    2015-03-01

    Degenerative Disc Disease (DDD) is one of the most common causes of low back pain, and is a major factor in limiting the quality of life of an individual usually as they enter older stages of life, the disc degeneration reduces the shock absorption available which in turn causes pain. Disc loss is one of the central processes in the pathogenesis of DDD. In this study, we investigated whether the image texture features quantified from magnetic resonance imaging (MRI) could be appropriate markers for diagnosis of DDD and prognosis of inter-vertebral disc loss. The main objective is to use simple image based biomarkers to perform prognosis of spinal diseases using non-invasive procedures. Our results from 65 subjects proved the higher success rates of the combination marker compared to the individual markers and in the future, we will extend the study to other spine regions to allow prognosis and diagnosis of DDD for a wider region.

  16. Time Localisation of Surface Defects on Optical Discs

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Wickerhauser, M.V.

    Many have experienced problems with their Compact Disc player when a disc with a scratch or a finger print is tried played. One way to improve the playability of discs with such a defect, is to locate the defect in time and then handle it in a special way. As a consequence this time localisation...

  17. Time Localisation of Surface Defects on Optical Discs

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Wickerhauser, M.V.

    2004-01-01

    Many have experienced problems with their Compact Disc Player when a disc with a scratch or a fingerprint is tried played. One way to improve the playability of discs with such a defect, is to locate the defect in time and then handle it in a special way. As a consequence this time localization...

  18. Analysis of an Assemblage of Discs Employing Interactive Graphics.

    Science.gov (United States)

    1980-12-01

    facilitate the program’s efficiency. Indeed, the ulsabilitv of tie distinct element method is pred icated on ef f ic ielt Irogramming techniques...paragraphs. Any subsequent user of DISC should not necessarily feel bound to this scheme. 33. At the outset of writing DISC, it was decided that a disc

  19. On the illumination of neutron star accretion discs

    Science.gov (United States)

    Wilkins, D. R.

    2018-03-01

    The illumination of the accretion disc in a neutron star X-ray binary by X-rays emitted from (or close to) the neutron star surface is explored through general relativistic ray tracing simulations. The applicability of the canonical suite of relativistically broadened emission line models (developed for black holes) to discs around neutron stars is evaluated. These models were found to describe well emission lines from neutron star accretion discs unless the neutron star radius is larger than the innermost stable orbit of the accretion disc at 6 rg or the disc is viewed at high inclination, above 60° where shadowing of the back side of the disc becomes important. Theoretical emissivity profiles were computed for accretion discs illuminated by hotspots on the neutron star surfaces, bands of emission and emission by the entirety of the hot, spherical star surface and in all cases, the emissivity profile of the accretion disc was found to be well represented by a single power law falling off slightly steeper than r-3. Steepening of the emissivity index was found where the emission is close to the disc plane and the disc can appear truncated when illuminated by a hotspot at high latitude. The emissivity profile of the accretion disc in Serpens X-1 was measured and found to be consistent with a single unbroken power law with index q=3.5_{-0.4}^{+0.3}, suggestive of illumination by the boundary layer between the disc and neutron star surface.

  20. A method for quantitative measurement of lumbar intervertebral disc structures

    DEFF Research Database (Denmark)

    Tunset, Andreas; Kjær, Per; Samir Chreiteh, Shadi

    2013-01-01

    There is a shortage of agreement studies relevant for measuring changes over time in lumbar intervertebral disc structures. The objectives of this study were: 1) to develop a method for measurement of intervertebral disc height, anterior and posterior disc material and dural sac diameter using MR...

  1. CT in diagnosis of recurrent vertebral disc hernias after preceding lumbar disc prolapse surgery

    International Nuclear Information System (INIS)

    Burval, S.; Nekula, J.; Vaverka, M.; Veliskova, J.

    1992-01-01

    20 patients with recurrent symptoms following operations for disc prolapse and resistant to treatment were studied by CT, using plain and enhanced images. The results have been analysed. In 10 patients a recurrence of disc prolapse was diagnosed, and this was confirmed surgically in 8 cases. In 2 patients there was epidural scarring. The findings indicate that differential diagnosis between scarring and recurring prolapse can by accurately made by this technique. (orig.) [de

  2. The life cycles of Be viscous decretion discs: fundamental disc parameters of 54 SMC Be stars

    Science.gov (United States)

    Rímulo, L. R.; Carciofi, A. C.; Vieira, R. G.; Rivinius, Th; Faes, D. M.; Figueiredo, A. L.; Bjorkman, J. E.; Georgy, C.; Ghoreyshi, M. R.; Soszyński, I.

    2018-05-01

    Be stars are main-sequence massive stars with emission features in their spectrum, which originates in circumstellar gaseous discs. Even though the viscous decretion disc model can satisfactorily explain most observations, two important physical ingredients, namely the magnitude of the viscosity (α) and the disc mass injection rate, remain poorly constrained. The light curves of Be stars that undergo events of disc formation and dissipation offer an opportunity to constrain these quantities. A pipeline was developed to model these events that use a grid of synthetic light curves, computed from coupled hydrodynamic and radiative transfer calculations. A sample of 54 Be stars from the OGLE survey of the Small Magellanic Cloud (SMC) was selected for this study. Because of the way our sample was selected (bright stars with clear disc events), it likely represents the densest discs in the SMC. Like their siblings in the Galaxy, the mass of the disc in the SMC increases with the stellar mass. The typical mass and angular momentum loss rates associated with the disc events are of the order of ˜10-10 M⊙ yr-1 and ˜5 × 1036 g cm2 s-2, respectively. The values of α found in this work are typically of a few tenths, consistent with recent results in the literature and with the ones found in dwarf novae, but larger than current theory predicts. Considering the sample as a whole, the viscosity parameter is roughly two times larger at build-up ( = 0.63) than at dissipation ( = 0.26). Further work is necessary to verify whether this trend is real or a result of some of the model assumptions.

  3. Spontaneous Resolution of Optic Disc Pit Maculopathy

    Directory of Open Access Journals (Sweden)

    Koushik Tripathy

    2017-06-01

    Full Text Available I read with interest the article reporting spontaneous resolution of optic disc pit maculopathy in a boy.1 Though the presence of an optic disc pit and associated macular involvement is undoubted in the presented case, the provided optical coherence tomography (OCT does not clearly show typical intraretinal schisis (Figure 1B1 at multiple retinal levels which may communicate with the pit. Instead, it shows a sub-internal limiting membrane (sub-ILM cavity. Such cavities are known to occur following the resolution of sub-ILM bleed due to various cause including Valsalva retinopathy,2 Terson syndrome, and also in some retinitis3 cases.4 In fact, some of these cavities may simulate a neurosensory retinal detachment or central serous chorioretinopathy on cursory clinical examination.5 To confirm that the features of the current patient1 are indeed related to the optic disc pit, it is necessary for the authors to provide an OCT scan which shows a connection of the presented cavity with the optic disc pit. Also, clear OCT scans of the fovea, both at presentation and at final follow-up would help our understanding of the visual recovery of the patient. The interval between the presenting (28 June 2012 OCT and final OCT (30 Nov 2012 is 5 months and not 6 months as described in the manuscript. For an effective comparison, both the presenting and final OCT scans should have been taken using either horizontal or vertical orientation over the macula. Though the spontaneous resolution of optic disc pit maculopathy is possible, visual recovery in usually unlikely and in such cases an alternate diagnosis needs to be excluded.

  4. Worrying Thoughts Limit Working Memory Capacity in Math Anxiety.

    Science.gov (United States)

    Shi, Zhan; Liu, Peiru

    2016-01-01

    Sixty-one high-math-anxious persons and sixty-one low-math-anxious persons completed a modified working memory capacity task, designed to measure working memory capacity under a dysfunctional math-related context and working memory capacity under a valence-neutral context. Participants were required to perform simple tasks with emotionally benign material (i.e., lists of letters) over short intervals while simultaneously reading and making judgments about sentences describing dysfunctional math-related thoughts or sentences describing emotionally-neutral facts about the world. Working memory capacity for letters under the dysfunctional math-related context, relative to working memory capacity performance under the valence-neutral context, was poorer overall in the high-math-anxious group compared with the low-math-anxious group. The findings show a particular difficulty employing working memory in math-related contexts in high-math-anxious participants. Theories that can provide reasonable interpretations for these findings and interventions that can reduce anxiety-induced worrying intrusive thoughts or improve working memory capacity for math anxiety are discussed.

  5. Simple arithmetic: not so simple for highly math anxious individuals.

    Science.gov (United States)

    Chang, Hyesang; Sprute, Lisa; Maloney, Erin A; Beilock, Sian L; Berman, Marc G

    2017-12-01

    Fluency with simple arithmetic, typically achieved in early elementary school, is thought to be one of the building blocks of mathematical competence. Behavioral studies with adults indicate that math anxiety (feelings of tension or apprehension about math) is associated with poor performance on cognitively demanding math problems. However, it remains unclear whether there are fundamental differences in how high and low math anxious individuals approach overlearned simple arithmetic problems that are less reliant on cognitive control. The current study used functional magnetic resonance imaging to examine the neural correlates of simple arithmetic performance across high and low math anxious individuals. We implemented a partial least squares analysis, a data-driven, multivariate analysis method to measure distributed patterns of whole-brain activity associated with performance. Despite overall high simple arithmetic performance across high and low math anxious individuals, performance was differentially dependent on the fronto-parietal attentional network as a function of math anxiety. Specifically, low-compared to high-math anxious individuals perform better when they activate this network less-a potential indication of more automatic problem-solving. These findings suggest that low and high math anxious individuals approach even the most fundamental math problems differently. © The Author (2017). Published by Oxford University Press.

  6. Worrying Thoughts Limit Working Memory Capacity in Math Anxiety.

    Directory of Open Access Journals (Sweden)

    Zhan Shi

    Full Text Available Sixty-one high-math-anxious persons and sixty-one low-math-anxious persons completed a modified working memory capacity task, designed to measure working memory capacity under a dysfunctional math-related context and working memory capacity under a valence-neutral context. Participants were required to perform simple tasks with emotionally benign material (i.e., lists of letters over short intervals while simultaneously reading and making judgments about sentences describing dysfunctional math-related thoughts or sentences describing emotionally-neutral facts about the world. Working memory capacity for letters under the dysfunctional math-related context, relative to working memory capacity performance under the valence-neutral context, was poorer overall in the high-math-anxious group compared with the low-math-anxious group. The findings show a particular difficulty employing working memory in math-related contexts in high-math-anxious participants. Theories that can provide reasonable interpretations for these findings and interventions that can reduce anxiety-induced worrying intrusive thoughts or improve working memory capacity for math anxiety are discussed.

  7. [Partial nucleotomy of the ovine disc as an in vivo model for disc degeneration].

    Science.gov (United States)

    Guder, E; Hill, S; Kandziora, F; Schnake, K J

    2009-01-01

    The aim of this study was to develop a suitable animal model for the clinical situation of progressive disc degeneration after microsurgical nucleotomy. Twenty sheep underwent standardised partial anterolateral nucleotomy at lumbar segment 3/4. After randomisation, 10 animals were sacrificed after 12 weeks (group 1). The remainder was sacrificed after 48 weeks (group 2). For radiological examination X-rays, MRI and post-mortem CT scans were performed. Lumbar discs L 3/4 with adjacent subchondral trabecular bone were harvested and analysed macroscopically and histologically. An image-analysing computer program was used to measure histomorphometric indices of bone structure. 17 segments could be evaluated. After 12 weeks (group 1) histological and radiological degenerative disc changes were noted. After 48 weeks (group 2), radiological signs in MRI reached statistical significance. Furthermore, group 2 showed significantly more osteophyte formations in CT scans. Histomorphometric changes of the disc and the adjacent vertebral bone structure suggest a significant progressive degenerative remodelling. The facet joints did not show any osteoarthrosis after 48 weeks. Partial nucleotomy of the ovine lumbar disc leads to radiological and histological signs of disc degeneration similar to those seen in humans after microsurgical nucleotomy. The presented in vivo model may be useful to evaluate new orthopaedic treatment strategies.

  8. Classroom Learning Environment and Gender: Do They Explain Math Self-Efficacy, Math Outcome Expectations, and Math Interest during Early Adolescence?

    Science.gov (United States)

    Deacon, Mary M.

    2011-01-01

    Despite initiatives to increase and broaden participation in science, technology, engineering, and mathematics (STEM) fields, women remain underrepresented in STEM. While U.S. girls and women perform as well as, if not better, than boys and men in math, research results indicate that there are significant declines in girls' math self-efficacy,…

  9. Addressing the Math-Practice Gap in Elementary School: Are Tablets a Feasible Tool for Informal Math Practice?

    Science.gov (United States)

    Stacy, Sara T; Cartwright, Macey; Arwood, Zjanya; Canfield, James P; Kloos, Heidi

    2017-01-01

    Students rarely practice math outside of school requirements, which we refer to as the "math-practice gap". This gap might be the reason why students struggle with math, making it urgent to develop means by which to address it. In the current paper, we propose that math apps offer a viable solution to the math-practice gap: Online apps can provide access to a large number of problems, tied to immediate feedback, and delivered in an engaging way. To substantiate this conversation, we looked at whether tablets are sufficiently engaging to motivate children's informal math practice. Our approach was to partner with education agencies via a community-based participatory research design. The three participating education agencies serve elementary-school students from low-SES communities, allowing us to look at tablet use by children who are unlikely to have extensive access to online math enrichment programs. At the same time, the agencies differed in several structural details, including whether our intervention took place during school time, after school, or during the summer. This allowed us to shed light on tablet feasibility under different organizational constraints. Our findings show that tablet-based math practice is engaging for young children, independent of the setting, the student's age, or the math concept that was tackled. At the same time, we found that student engagement was a function of the presence of caring adults to facilitate their online math practice.

  10. Math Description Engine Software Development Kit

    Science.gov (United States)

    Shelton, Robert O.; Smith, Stephanie L.; Dexter, Dan E.; Hodgson, Terry R.

    2010-01-01

    The Math Description Engine Software Development Kit (MDE SDK) can be used by software developers to make computer-rendered graphs more accessible to blind and visually-impaired users. The MDE SDK generates alternative graph descriptions in two forms: textual descriptions and non-verbal sound renderings, or sonification. It also enables display of an animated trace of a graph sonification on a visual graph component, with color and line-thickness options for users having low vision or color-related impairments. A set of accessible graphical user interface widgets is provided for operation by end users and for control of accessible graph displays. Version 1.0 of the MDE SDK generates text descriptions for 2D graphs commonly seen in math and science curriculum (and practice). The mathematically rich text descriptions can also serve as a virtual math and science assistant for blind and sighted users, making graphs more accessible for everyone. The MDE SDK has a simple application programming interface (API) that makes it easy for programmers and Web-site developers to make graphs accessible with just a few lines of code. The source code is written in Java for cross-platform compatibility and to take advantage of Java s built-in support for building accessible software application interfaces. Compiled-library and NASA Open Source versions are available with API documentation and Programmer s Guide at http:/ / prim e.jsc.n asa. gov.

  11. Learning Math With My Father: A Memoir

    Directory of Open Access Journals (Sweden)

    Yolanda De La CRUZ

    2012-07-01

    Full Text Available If he is indeed wise he does not bid you enter the house of his wisdom, but rather leads you to the threshold of your own mind. Kahlil Gibran. We all build our own houses of wisdom, each of us; we cannot build them for each other. Teachers cannot simply invite students into their houses of wisdom, but can often find ways to help learners to enter and explore their own minds. While Constructivism has had a positive impact on the teaching and learning of literacy mathematics instruction continues to rely heavily on rote memorization and drills. As a young child, I learned to love math. My love of math stems from learning math with my father. He did not focus on rote memorization and drills. The primary emphasis was for a real purpose. My self-confidence was enforced when he started me out with problems that were less difficult and had many different solutions. These solutions were valued and respected, which allowed me to trust in my own problem solving abilities. How can we hope to lead children to the thresholds of their own minds when we remain intent on forcing them into our houses of wisdom? What alternative ways can we devise of interacting with children that respect their confidence and leave intact their levels of understanding, that lead them to the thresholds of their own minds excited about entering?

  12. The diagnosis of internal disc disruption with CT discography

    International Nuclear Information System (INIS)

    Liu Miao; Chen Xingcan; Li Xiaohong; Pan Yongqin

    2008-01-01

    Objective: To study the value of diagnosis for internal disc disruption (IDD)with CT discography(CTD). Methods: 42 discs of 32 patients showing no disc herniation on CT or MRI, but suffering from chronic low back pain, were undertaken CTD to work out the types of CTD with correlation between contrast medium dosages and the induction of pain. Results: CTD demonstrated 4 types of IDD which was individually correlated with the contrast dosages and induced pain; furthermore the dosages for positive and negative disc cases showed significant differece (P<0.01). Conclusions: CTD can show the direct sign of internal disc disruption, providing more information than conventional discography. (authors)

  13. Primary maths anyone can feed skittles to sharks

    CERN Document Server

    Tiley-Nunn, Nick

    2014-01-01

    Primary maths is stereotypically loved by a few hairy oddballs, tolerated by most sane primary practitioners; loathed by many. With the right approach, however; the right mindset and sense of the impossible being achievable, maths can be moulded into the diamond in the rough of the primary curriculum. Enter Nick Tiley-Nunn: Britain's most imaginative, most exciting primary maths specialist. Over years of practice he has generated ideas about the teaching of maths that are so distinct, so far out and so utterly brilliant that any primary teacher struggling to grasp the nettle of teaching long division will emerge from communing with his ideas not just with some clichéd sense that ‘maths can be fun', but that it can be brilliant, life-enhancing and truly hilarious. This book presents ideas for primary maths teaching so wildly creative and so full of the joy of life that any classroom of kids will be grateful you read it.

  14. Metacognition and Confidence: Comparing Math to Other Academic Subjects

    Directory of Open Access Journals (Sweden)

    Shanna eErickson

    2015-06-01

    Full Text Available Two studies addressed student metacognition in math, measuring confidence accuracy about math performance. Underconfidence would be expected in light of pervasive math anxiety. However, one might alternatively expect overconfidence based on previous results showing overconfidence in other subject domains. Metacognitive judgments and performance were assessed for biology, literature, and mathematics tests. In Study 1, high school students took three different tests and provided estimates of their performance both before and after taking each test. In Study 2, undergraduates similarly took three shortened SAT II Subject Tests. Students were overconfident in predicting math performance, indeed showing greater overconfidence compared to other academic subjects. It appears that both overconfidence and anxiety can adversely affect metacognitive ability and can lead to math avoidance. The results have implications for educational practice and other environments that require extensive use of math.

  15. Queixas auditivas de disc jockeys da cidade de Recife Auditory complaints in disc jockeys in Recife

    Directory of Open Access Journals (Sweden)

    Eliza Maia de Britto Macedo

    2011-06-01

    Full Text Available OBJETIVO: investigar a ocorrência de queixas auditivas em disc jockeys da cidade de Recife/PE. MÉTODOS: foi realizada uma entrevista com 30 disc jockeys, com idade entre 19 e 28 anos, abordando informações ocupacionais, conhecimentos gerais sobre o ruído e queixas auditivas (diminuição da acuidade auditiva, desconforto a sons intensos, zumbido, sensação de ouvido abafado e otalgia. A análise foi realizada por meio de abordagem quantitativa, utilizando o teste estatístico t-student. RESULTADOS: dentre os dados mais relevantes, destacam-se: 46,7% dos disc jockeys apresentaram, espontaneamente, queixas auditivas, em especial, a diminuição da acuidade auditiva (relatada por todos os sujeitos; 14 disc jockeys (46,67% referiram desconforto a sons intensos e 13 (43,33% mencionaram zumbido. Todos afirmaram ter conhecimento sobre os riscos do ruído para a saúde auditiva, mas 76,7% não realizam qualquer medida preventiva de suas consequências. A perda auditiva foi referida pelos sujeitos como o principal risco da exposição a níveis intensos de pressão sonora. CONCLUSÃO: todos os disc jockeys apresentaram queixa de perda auditiva e, entre as demais queixas auditivas, destacaram-se o desconforto a sons intensos e o zumbido. Tendo em vista a irreversibilidade da perda auditiva induzida por elevados níveis de pressão sonora, os disc jockeys devem ser periodicamente avaliados a fim de que se confirme ou não a perda auditiva de que se queixaram e, caso ela exista, deve ser monitorada para que seja passível de intervenção pelo fonoaudiólogo. Desta forma, percebe-se a necessidade de atuação da Fonoaudiologia junto aos disc jockeys, uma vez que poder-se-á propiciar a otimização do exercício profissional com o mínimo de risco possível.PURPOSE: to investigate the occurrence of auditory complaints in disc jockeys from the city of Recife/PE. METHODS: an interview was carried through with 30 disc jockeys aged between 19 and 48 years

  16. Fas ligand exists on intervertebral disc cells: a potential molecular mechanism for immune privilege of the disc.

    Science.gov (United States)

    Takada, Toru; Nishida, Kotaro; Doita, Minoru; Kurosaka, Masahiro

    2002-07-15

    Rat and human intervertebral disc specimens were examined immunohistochemically. Reverse transcription polymerase chain reaction (RT-PCR) analysis was also performed on rat disc tissue to demonstrate the existence of Fas ligand. To clarify the existence of Fas ligand on intact intervertebral disc cells. The nucleus pulposus has been reported to be an immune-privileged site. The immune-privileged characteristic in other tissues such as the retina and testis has been attributed to the local expression of Fas ligand, which acts by inducing apoptosis of invading Fas-positive T-cells. The existence of Fas ligand in normal disc cells has not yet been addressed. Skeletally mature SD male rats were killed, and the coccygeal discs were harvested. Human disc specimens were obtained from idiopathic scoliosis patients during surgical procedures. Immunohistochemical staining for Fas ligand was performed for cross-sections of the discs by standard procedures. Reverse transcription polymerase chain reaction analysis was also carried out to demonstrate Fas ligand mRNA expression on rat intervertebral discs. Testes of the rats were used for positive controls, and muscles were used for negative controls. The sections were observed by light microscopy. The nucleus pulposus cells exhibited intense positive immune staining for Fas ligand. The outer anulus fibrosus cells and notochordal cells exhibited little immunopositivity. The positive controls exhibited positive immune staining, and the negative control showed no immunopositivity. The result of RT-PCR confirmed the existence of Fas ligand in disc cells. The human nucleus pulposus cells showed a similar predilection to rat disc cells. We demonstrated the existence of Fas ligand on disc cells, which should play a key role in the potential molecular mechanism to maintain immune privilege of the disc. Immune privilege and Fas ligand expression of the intervertebral disc may provide a new insight for basic science research as well as

  17. MR image assessment of disc configuration and degree of anterior disc displacement in internal derangement related to age

    International Nuclear Information System (INIS)

    Igarashi, Chinami; Kobayashi, Kaoru; Imanaka, Masahiro; Yuasa, Masao; Yamamoto, Akira

    1999-01-01

    This study was designed to evaluate the configuration of the articular disc and degree of anterior disc displacement on magnetic resonance (MR) imagings in temporomandibular joints (TMJs) with internal derangement. A total of 363 joints diagnosed as having anterior disc displacement with reduction (ADD w R) and 523 joints diagnosed as having anterior disc displacement without reduction (ADD wo R) by MR imaging were examined. These joints did not show severe osseous changes on the condylar head or glenoid fossa. We assessed the configuration of the articular disc and degree of anterior disc displacement. In the ADD w R group, 82.6% of the articular discs showed biconcave configuration; enlargement of the posterior band in 4.6%, biconvex configuration in 0.5%, and others in 10.7%. Moreover 62.5% of the discs showed a slight degree of anterior disc displacement; were 27.2% moderately displaced and were 10.2% severe displaced. The prevalence of slightly displaced discs was higher in the TMJs of cases over 50 years of age than in cases under 30 years in the ADD w R group. On the other hand, in the ADD wo R group 35.9% of the articular discs showed biconcave configuration; enlargement of the posterior band in 12.6%, biconvex configuration in 25.4%, and others in 22.3%. Furthermore, 4.4% of the discs were slightly displaced; 43.9% moderately displaced and 51.6% were severely displaced. The prevalence of severely displaced and deformed discs in joints of cases over 40 years of age was high in the ADD wo R group. The prevalence of slightly displaced biconcave discs was higher in the ADD w R group. The other hand, the prevalence of severely displaced deformed discs was higher in the ADD wo R group. MR findings of internal derangement of the TMJ were found to be significantly correlated with age. (author)

  18. Metacognitive awareness and math anxiety in gifted students

    OpenAIRE

    Hakan Sarıcam; Üzeyir Ogurlu

    2015-01-01

    The basic purpose of this study has been to examine the relationships between metacognitive awareness and maths anxiety in gifted students. The second aim was to compare with gifted and non-gifted students’ metacognitive awareness and maths anxiety levels. The participants were 300 (150 gifted, 150 non-gifted) volunteer secondary school students in Turkey. The mean age of the participants was 12.56 years ranging from 12 to 13 years. For gathering data, the Maths Anxiety Scale for Elementary S...

  19. Insecure attachment is associated with math anxiety in middle childhood

    OpenAIRE

    Bosmans, Guy; De Smedt, Bert

    2015-01-01

    Children?s anxiety for situations requiring mathematical problem solving, a concept referred to as math anxiety, has a unique and detrimental impact on concurrent and long-term mathematics achievement and life success. Little is known about the factors that contribute to the emergence of math anxiety. The current study builds on the hypothesis that math anxiety might reflect a maladaptive affect regulation mechanism that is characteristic for insecure attachment relationships. To test this hy...

  20. What to Do About Canada's Declining Math Scores?

    OpenAIRE

    Anna Stokke

    2015-01-01

    The declining performance of Canadian students on international math assessments should worry Canadians and their provincial governments. Strong mathematics knowledge is required for success in the workforce, and early achievement in math is one of the best predictors of later academic success and future career options. Between 2003 and 2012, all but two Canadian provinces showed statistically significant declines in math scores on international exams administered by the Organization for Econ...

  1. Examination of turbine discs from nuclear power plants

    International Nuclear Information System (INIS)

    Czajkowski, C.J.; Weeks, J.R.

    1982-01-01

    Investigations were performed on a cracked turbine disc from the Cooper Nuclear Power Station, and on two failed turbine discs (governor and generator ends) from the Yankee-Rowe Nuclear Power Station. Cooper is a boiling water reactor (BWR) which went into commercial operation in July 1974, and Yankee-Rowe is a pressurized water reactor (PWR) which went into commercial operation in June 1961. Cracks were identified in the bore of the Cooper disc after 41,913 hours of operation, and the disc removed for repair. At Yankee-Rowe two discs failed after 100,000 hours of operation. Samples of the Cooper disc and both Yankee-Rowe disc (one from the governor and one from the generator end of the LP turbine) were sent to Brookhaven National Laboratory (BNL) for failure analysis

  2. A descriptive study of high school Latino and Caucasian students' values about math, perceived math achievement and STEM career choice

    Science.gov (United States)

    Rodriguez Flecha, Samuel

    The purpose of this study was to examine high school students' math values, perceived math achievement, and STEM career choice. Participants (N=515) were rural high school students from the U.S. Northwest. Data was collected by administering the "To Do or Not to Do:" STEM pilot survey. Most participants (n=294) were Latinos, followed by Caucasians (n=142). Fifty-three percent of the students rated their math achievement as C or below. Of high math students, 57% were male. Females were 53% of low math students. Caucasians (61%) rated themselves as high in math in a greater proportion than Latinos (39%). Latinos (58%) rated themselves as low in math in a greater proportion than Caucasians (39%). Math Values play a significant role in students' perceived math achievement. Internal math values (r =.68, R2 =.46, p =.001) influenced perceived math achievement regardless of gender (males: r =.70, R2 =.49, p =.001; females: r =.65, R2 =.43, p =.001), for Latinos (r =.66, R2 =.44, p =.001), and Caucasians (r =.72, R2 =.51, p =.001). External math values (r =.53, R2 =.28, p =.001) influenced perceived math achievement regardless of gender (males: r =.54, R2 =.30, p =.001; females: r =.49, R2 =.24, p =.001), for Latinos (r =.47, R2 =.22, p =.001), and Caucasians (r =.58, R2 =.33, p =.001). Most high-math students indicated an awareness of being good at math at around 11 years old. Low-math students said that they realized that math was difficult for them at approximately 13 years of age. The influence of parents, teachers, and peers may vary at different academic stages. Approximately half of the participants said there was not a person who had significantly impacted their career choice; only a minority said their parents and teachers were influencing them to a STEM career. Parents and teachers are the most influential relationships in students' career choice. More exposure to STEM role models and in a variety of professions is needed. Possible strategies to impact students

  3. Are Collapsed Cervical Discs Amenable to Total Disc Arthroplasty?: Analysis of Prospective Clinical Data With 2-Year Follow Up.

    Science.gov (United States)

    Patwardhan, Avinash G; Carandang, Gerard; Voronov, Leonard I; Havey, Robert M; Paul, Gary A; Lauryssen, Carl; Coric, Domagoj; Dimmig, Thomas; Musante, David

    2016-12-15

    Analysis of prospectively collected radiographic data. To investigate the influence of preoperative index-level range of motion (ROM) and disc height on postoperative ROM after cervical total disc arthroplasty (TDA) using compressible disc prostheses. Clinical studies demonstrate benefits of motion preservation over fusion; however, questions remain unanswered as to which preoperative factors have the ability to identify patients who are most likely to have good postoperative motion, which is the primary rationale for TDA. We analyzed prospectively collected data from a single-arm, multicenter study with 2-year follow up of 30 patients with 48 implanted levels. All received compressible cervical disc prostheses of 6 mm-height (M6C, Spinal Kinetics, Sunnyvale, CA). The influence of index-level preoperative disc height and ROM (each with two levels: below-median and above-median) on postoperative ROM was analyzed using 2 x 2 ANOVA. We further analyzed the radiographic outcomes of a subset of discs with preoperative height less than 3 mm, the so-called "collapsed" discs. Shorter (3.0 ± 0.4 mm) discs were significantly less mobile preoperatively than taller (4.4 ± 0.5 mm) discs (6.7° vs. 10.5°, P = 0.01). The postoperative ROM did not differ between the shorter and taller discs (5.6° vs. 5.0°, P = 0.63). Tall discs that were less mobile preoperatively had significantly smaller postoperative ROM than short discs with above-median preoperative mobility (P < 0.05). The "collapsed discs" (n = 8) were less mobile preoperatively compared with all discs combined (5.1° vs. 8.6°, P < 0.01). These discs were distracted to more than two times the preoperative height, from 2.6 to 5.7 mm, and had significantly greater postoperative ROM than all discs combined (7.6° vs. 5.3°, P < 0.05). We observed a significant interaction between preoperative index-level disc height and ROM in influencing postoperative ROM. Although limited by small sample

  4. Cognitive consistency and math-gender stereotypes in Singaporean children.

    Science.gov (United States)

    Cvencek, Dario; Meltzoff, Andrew N; Kapur, Manu

    2014-01-01

    In social psychology, cognitive consistency is a powerful principle for organizing psychological concepts. There have been few tests of cognitive consistency in children and no research about cognitive consistency in children from Asian cultures, who pose an interesting developmental case. A sample of 172 Singaporean elementary school children completed implicit and explicit measures of math-gender stereotype (male=math), gender identity (me=male), and math self-concept (me=math). Results showed strong evidence for cognitive consistency; the strength of children's math-gender stereotypes, together with their gender identity, significantly predicted their math self-concepts. Cognitive consistency may be culturally universal and a key mechanism for developmental change in social cognition. We also discovered that Singaporean children's math-gender stereotypes increased as a function of age and that boys identified with math more strongly than did girls despite Singaporean girls' excelling in math. The results reveal both cultural universals and cultural variation in developing social cognition. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. A Correlation of Community College Math Readiness and Student Success

    Science.gov (United States)

    Brown, Jayna Nicole

    Although traditional college students are more prepared for college-level math based on college admissions tests, little data have been collected on nontraditional adult learners. The purpose of this study was to investigate relationships between math placement tests and community college students' success in math courses and persistence to degree or certificate completion. Guided by Tinto's theory of departure and student retention, the research questions addressed relationships and predictability of math Computer-adaptive Placement Assessment and Support System (COMPASS) test scores and students' performance in math courses, persistence in college, and degree completion. After conducting correlation and regression analyses, no significant relationships were identified between COMPASS Math test scores and students' performance (n = 234) in math courses, persistence in college, or degree completion. However, independent t test and chi-squared analyses of the achievements of college students who tested into Basic Math (n = 138) vs. Introduction to Algebra (n = 96) yielded statistically significant differences in persistence (p = .039), degree completion (p college students' math competencies and degree achievement.

  6. Evaluation of bone and disc configuration in TMJ internal derangement

    International Nuclear Information System (INIS)

    Park, Cheol Woo; Hwang, Eui Hwan; Lee, Sang Rae

    2001-01-01

    To investigate bone and disc configuration on MR images in internal derangement related to age. MR images of 150 TMJs in 107 patients were analyzed to determine the morphologic changes. Two groups were distinguished to be correlated with age. Group 1 consisted of TMJs that were diagnosed as having anterior disc displacement with reduction (ADDwR), and Group 2 consisted of TMJs that were diagnosed as having anterior disc displacement without reduction (ADDwR). We assessed the configuration of the articular disc, degree of anterior disc displacement, and osseous changes of TMJs. The third decade (83 of 150 joints) was most frequent in this study. In the ADDwR group biconcave disc was most frequent at all ages except fifth decade, but in the ADDwoR group deformed discs was most frequent at third and forth decades. In the ADDwR group slightly displaced discs was most frequent at all ages, but in the ADDwoR group severely displaced discs was most frequent at second decade, and the degree of disc displacement was increased with aging over 30 years of age. TM joints showed osseous changes in 17% of the ADDwR group, and in 30% of the ADDwoR group. MR findings of osseous changes of the TMJ were not found to be significantly correlated with age. The prevalence of deformation of disc, displacement of disc, and osseous changes of TMJ was higher in the ADDwoR group than in the ADDwR group. MR findings of disc configuration and degree of disc displacement were found to be correlated with age

  7. Cervical disc arthroplasty: Pros and cons.

    Science.gov (United States)

    Moatz, Bradley; Tortolani, P Justin

    2012-01-01

    Cervical disc arthroplasty has emerged as a promising potential alternative to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients. Despite a history of excellent outcomes after ACDF, the question as to whether a fusion leads to adjacent segment degeneration remains unanswered. Numerous US investigational device exemption trials comparing cervical arthroplasty to fusion have been conducted to answer this question. This study reviews the current research regarding cervical athroplasty, and emphasizes both the pros and cons of arthroplasty as compared with ACDF. Early clinical outcomes show that cervical arthroplasty is as effective as the standard ACDF. However, this new technology is also associated with an expanding list of novel complications. Although there is no definitive evidence that cervical disc replacement reduces the incidence of adjacent segment degeneration, it does show other advantages; for example, faster return to work, and reduced need for postoperative bracing.

  8. MR imaging of degenerative disc disease

    International Nuclear Information System (INIS)

    Farshad-Amacker, Nadja A.; Farshad, Mazda; Winklehner, Anna; Andreisek, Gustav

    2015-01-01

    Highlights: • This systematic literature review summarizes the current knowledge on MR imaging in degenerative disc disease. • Different classification systems for segmental spine degeneration are summarized. • It outlines the diagnostic limitations of MR imaging. - Abstract: Magnet resonance imaging (MRI) is the most commonly used imaging modality for diagnosis of degenerative disc disease (DDD). Lack of precise observations and documentation of aspects within the complex entity of DDD might partially be the cause of poor correlation of radiographic findings to clinical symptoms. This literature review summarizes the current knowledge on MRI in DDD and outlines the diagnostic limitations. The review further sensitizes the reader toward awareness of potentially untended aspects of DDD and the interaction of DDD and endplate changes. A summary of the available classifications for DDD is provided

  9. MR imaging of degenerative disc disease

    Energy Technology Data Exchange (ETDEWEB)

    Farshad-Amacker, Nadja A., E-mail: nadja.farshad@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, Zurich (Switzerland); Farshad, Mazda [Department of Orthopaedic Surgery, Balgrist University Hospital, Zurich (Switzerland); Winklehner, Anna; Andreisek, Gustav [Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, Zurich (Switzerland)

    2015-09-15

    Highlights: • This systematic literature review summarizes the current knowledge on MR imaging in degenerative disc disease. • Different classification systems for segmental spine degeneration are summarized. • It outlines the diagnostic limitations of MR imaging. - Abstract: Magnet resonance imaging (MRI) is the most commonly used imaging modality for diagnosis of degenerative disc disease (DDD). Lack of precise observations and documentation of aspects within the complex entity of DDD might partially be the cause of poor correlation of radiographic findings to clinical symptoms. This literature review summarizes the current knowledge on MRI in DDD and outlines the diagnostic limitations. The review further sensitizes the reader toward awareness of potentially untended aspects of DDD and the interaction of DDD and endplate changes. A summary of the available classifications for DDD is provided.

  10. Material Science in Cervical Total Disc Replacement

    Science.gov (United States)

    Pham, Martin H.; Mehta, Vivek A.; Tuchman, Alexander; Hsieh, Patrick C.

    2015-01-01

    Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

  11. Material Science in Cervical Total Disc Replacement

    Directory of Open Access Journals (Sweden)

    Martin H. Pham

    2015-01-01

    Full Text Available Current cervical total disc replacement (TDR designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti, and cobalt-chrome (CoCr. These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

  12. Material Science in Cervical Total Disc Replacement.

    Science.gov (United States)

    Pham, Martin H; Mehta, Vivek A; Tuchman, Alexander; Hsieh, Patrick C

    2015-01-01

    Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

  13. The Astral Curved Disc of Chevroches (France)

    Science.gov (United States)

    Devevey, F. Rousseau, A.

    2009-08-01

    The excavation of the unexplored secondary agglomeration in Chevroches (Nièvre), from 2001 to 2002, directed by F. Devevey (INRAP), has led to the discovery of an astrological bronze curved disc of a type unknown in the ancient world; it is inscribed with three lines in Greek transcribing Egyptian an Roman months, and the twelve signs of the zodiac. This article presents the first observations.

  14. Influence of degenerative changes of intervertebral disc

    Directory of Open Access Journals (Sweden)

    WANG Yi

    2012-04-01

    Full Text Available 【Abstract】Objective: To investigate the material properties of normal and degenerated intervertebral discs (IVDs and examine the effect of degenerative changes on IVD pathology. Methods: A computer-based online search was under-taken to identify English articles about material properties of IVDs published from January 1950 to 2011 in PubMed database. The retrieved keywords included material properties, intervertebral disc and degeneration. Based on the principles of reliability, advancement and efficiency, the obtained data were primarily examined, and the original source was retrieved to read the full-text. Repetitive articles were excluded. The data of material properties of normal and degenerated IVDs were summarized and analyzed by meta-analysis. Results: The data of Young's modulus, Poisson's ratio, shear modulus, hydraulic permeability and intradiscal pres-sure of normal and degenerated IVDs were obtained. Com-pared with normal IVDs, the Young's modulus and shear modulus of annulus fibrosus and nucleus pulposus were higher in degenerated IVDs, the Poisson's ratio was lower while the hydraulic permeability and intradiscal pressure were higher. Besides, the degeneration-related alterations in IVDs had an influence both on itself and other spinal structures, leading to diseases such as bulging disc, discogenic pain and spinal stenosis. Meanwhile, the heavy mechanical loading and injury indicated important pathways to IVD degeneration. Conclusions: To a certain extent, the degenerative changes of IVD influence its material properties. And the degeneration-related alterations of composition can cause structural failure of IVDs, leading to injuries and diseases. Key words: Intervertebral disc; Mechanical phenomena; Degeneration; Elastic modulus; Permeability; Pathology

  15. Can Low-Cost Online Summer Math Programs Improve Student Preparation for College-Level Math? Evidence from Randomized Experiments at Three Universities

    Science.gov (United States)

    Chingos, Matthew M.; Griffiths, Rebecca J.; Mulhern, Christine

    2017-01-01

    Every year many students enter college without the math preparation needed to succeed in their desired programs of study. Many of these students struggle to catch up, especially those who are required to take remedial math courses before entering college-level math. Increasing the number of students who begin at the appropriate level of math has…

  16. Trajectories of Self-Perceived Math Ability, Utility Value and Interest across Middle School as Predictors of High School Math Performance

    Science.gov (United States)

    Petersen, Jennifer Lee; Hyde, Janet Shibley

    2017-01-01

    Although many studies have documented developmental change in mathematics motivation, little is known about how these trends predict math performance. A sample of 288 participants from the United States reported their perceived math ability, math utility value and math interest in 5th, 7th and 9th grades. Latent growth curve models estimated…

  17. Optic disc and peripapillary retinal nerve fiber layer characteristics associated with glaucomatous optic disc in young myopia.

    Science.gov (United States)

    Lee, Jong Eun; Sung, Kyung Rim; Park, Ji Min; Yoon, Joo Young; Kang, Sung Yong; Park, Sung Bae; Koo, Hyung Jin

    2017-03-01

    To explore optic disc and peripapillary retinal nerve fiber layer (RNFL) features associated with glaucomatous optic disc (GOD) in young myopia. Presence of GOD, optic disc tilt, and disc torsion were determined using fundus photographs. If the measured disc tilt ratio was >1.3, the optic disc was classified as tilted. Optic disc torsion was defined as a >15° deviation in the long axis of the optic disc from the vertical meridian. The average and four quadrants RNFL thicknesses were assessed using spectral domain optical coherence tomography (SD-OCT). Logistic regression analyses were performed to identify factors associated with the presence of GOD. Nine hundred and sixty myopic subjects were recruited from four refractive surgery clinic databases. The mean age was 26.6 ± 5.7 years and spherical equivalent (SE) was -5.5 ± 2.5 diopters. Among 960 eyes, 26 (2.7%) received GOD group classification. Among 934 normal eyes, 290 (31.0%) had titled optic discs. Eighteen eyes (69.2%) in the GOD group had tilted optic discs. When compared to normal eyes, the GOD group had significantly higher tilt ratios (1.4 ± 0.2 vs. 1.2 ± 0.1, p Optic disc tilt was found in approximately one-third of young myopic eyes and was independently associated with the presence of GOD.

  18. Dynamic analysis of three autoventilated disc brakes

    Directory of Open Access Journals (Sweden)

    Ricardo A. García-León

    2017-09-01

    Full Text Available The braking system of a car must meet several requirements, among which safety is the most important. It is also composed of a set of mechanical parts such as springs, different types of materials (Metallic and Non Metallic, gases and liquids. The brakes must work safely and predictably in all circumstances, which means having a stable level of friction, in any condition of temperature, humidity and salinity of the environment. For a correct design and operation of brake discs, it is necessary to consider different aspects, such as geometry, type of material, mechanical strength, maximum temperature, thermal deformation, cracking resistance, among others. Therefore, the main objective of this work is to analyze the dynamics and kinetics of the brake system from the pedal as the beginning of mathematical calculations to simulate the behavior and Analysis of Finite Elements (FEA, with the help of SolidWorks Simulation Software. The results show that the third brake disc works best in relation to the other two discs in their different working conditions such as speed and displacement in braking, concluding that depending on the geometry of the brake and the cooling channels these systems can be optimized that are of great importance for the automotive industry.

  19. Percutaneous treatment of intervertebral disc herniation.

    Science.gov (United States)

    Buy, Xavier; Gangi, Afshin

    2010-06-01

    Interventional radiology plays a major role in the management of symptomatic intervertebral disc herniations. In the absence of significant pain relief with conservative treatment including oral pain killers and anti-inflammatory drugs, selective image-guided periradicular infiltrations are generally indicated. The precise control of needle positioning allows optimal distribution of steroids along the painful nerve root. After 6 weeks of failure of conservative treatment including periradicular infiltration, treatment aiming to decompress or remove the herniation is considered. Conventional open surgery offers suboptimal results and is associated with significant morbidity. To achieve minimally invasive discal decompression, different percutaneous techniques have been developed. Their principle is to remove a small volume of nucleus, which results in an important reduction of intradiscal pressure and subsequently reduction of pressure inside the disc herniation. However, only contained disc herniations determined by computed tomography or magnetic resonance are indicated for these techniques. Thermal techniques such as radiofrequency or laser nucleotomy seem to be more effective than purely mechanical nucleotomy; indeed, they achieve discal decompression but also thermal destruction of intradiscal nociceptors, which may play a major role in the physiopathology of discal pain. The techniques of image-guided spinal periradicular infiltration and percutaneous nucleotomy with laser and radiofrequency are presented with emphasis on their best indications.

  20. Can Exercise Positively Influence the Intervertebral Disc?

    Science.gov (United States)

    Belavý, Daniel L; Albracht, Kirsten; Bruggemann, Gert-Peter; Vergroesen, Pieter-Paul A; van Dieën, Jaap H

    2016-04-01

    To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a narrative review. The majority of the available data come from cell or whole-disc loading models and animal exercise models. However, some studies have examined the impact of specific sports on IVD degeneration in humans and acute exercise on disc size. Based on the data available in the literature, loading types that are likely beneficial to the IVD are dynamic, axial, at slow to moderate movement speeds, and of a magnitude experienced in walking and jogging. Static loading, torsional loading, flexion with compression, rapid loading, high-impact loading and explosive tasks are likely detrimental for the IVD. Reduced physical activity and disuse appear to be detrimental for the IVD. We also consider the impact of genetics and the likelihood of a 'critical period' for the effect of exercise in IVD development. The current review summarises the literature to increase awareness amongst exercise, rehabilitation and ergonomic professionals regarding IVD health and provides recommendations on future directions in research.

  1. [Surgical treatment of thoracic disc herniation].

    Science.gov (United States)

    Hrabálek, L; Kalita, O; Langová, K

    2010-08-01

    The aim of this study was to compare the efficiency of different surgical approaches to thoracic disc herniation, and to show the role of segmental fusion and selection of an appropriate microsurgical decompression technique for the successful outcome of surgery. A group of 27 patients, 10 men and 17 women, between 31 and 70 years (average age, 49.33 years) were included in this prospective study. They underwent surgery for thoracic degeneration disc disease in the period from June 1994 to August 2008. In all patients, the severity of myelopathy was assessed using the grading Frankel system and JOA score, axial and radicular pain intensity was evaluated with VAS and ODI rating systems. The diagnosis was established on the basis of thoracic spine radiography, thoracic spine MRI and a CT scan of the segment. A total of 30 thoracic segments, in the range of Th4/Th5 to Th12/L1, were indicated for surgery. Localisation of the hernia was medial at 19 segments, mediolateral at three and lateral at eight segments. Soft disc herniation was found in 17 cases and hard disc protrusion at the remaining 13 segments. Surgery for significant myelopathy was carried out in 23 patients and for pain in four patients. According to the surgical procedure used, the patients were allocated to two groups: group A comprised 10 patients treated without disc replacement through a laminectomy or a costotransversectomy exposure, and group B consisted of 17 patients undergo- ing intersomatic fusion via a thoracotomy. Clinical and radiographic examinations were made at regular intervals for at least 1 year of follow-up. The results of clinical assessment, including JOA scores, JOA Recovery Rate, VAS scores at rest and after exercise and ODI, were statistically analysed for each group and compared. There was a statistically significant difference in JOA evaluation of myelopathy between the groups in group A, the mean JOA score declined from 7.9 to 7.0, i.e., -0.9 point, while in group B it

  2. Chipping machines: disc and drum energy requirements

    Directory of Open Access Journals (Sweden)

    Alessio Facello

    2013-09-01

    Full Text Available Air pollution and fossil fuel reserves exhaustion are increasing the importance of the biomass-derived products, in particular wood, as source of clean and renewable energy for the production of electricity or steam. In order to improve the global efficiency and the entire production chain, we have to evaluate the energetic aspects linked to the process of transformation, handling and transport of these materials. This paper reports results on a comparison between two chippers of similar size using different cutting technology: disc and drum tool respectively. During trials, fuel consumption, PTO torque and speed, processing time and weight of processed material were recorded. Power demand, fuel consumption, specific energy and productivity were computed. The machine was fed with four different feedstock types (chestnut logs, poplar logs, poplar branches, poplar sawmill residues. 15 repetitions for each combination of feedstock-tool were carried out. The results of this study show that the disc tool requires, depending on the processed material, from 12 to 18% less fuel per unit of material processed than the drum tool, and consequently, from 12 to 16% less specific energy. In particular, the highest difference between tools was found in branches processing whereas the smallest was in poplar logs. Furthermore the results of the investigation indicate, that, in testing conditions, the productivity of drum tool is higher (8% than disc tool.

  3. Accretion disc origin of the Earth's water.

    Science.gov (United States)

    Vattuone, Luca; Smerieri, Marco; Savio, Letizia; Asaduzzaman, Abu Md; Muralidharan, Krishna; Drake, Michael J; Rocca, Mario

    2013-07-13

    Earth's water is conventionally believed to be delivered by comets or wet asteroids after the Earth formed. However, their elemental and isotopic properties are inconsistent with those of the Earth. It was thus proposed that water was introduced by adsorption onto grains in the accretion disc prior to planetary growth, with bonding energies so high as to be stable under high-temperature conditions. Here, we show both by laboratory experiments and numerical simulations that water adsorbs dissociatively on the olivine {100} surface at the temperature (approx. 500-1500 K) and water pressure (approx. 10⁻⁸ bar) expected for the accretion disc, leaving an OH adlayer that is stable at least up to 900 K. This may result in the formation of many Earth oceans, provided that a viable mechanism to produce water from hydroxyl exists. This adsorption process must occur in all disc environments around young stars. The inevitable conclusion is that water should be prevalent on terrestrial planets in the habitable zone around other stars.

  4. Math Anxiety Assessment with the Abbreviated Math Anxiety Scale: Applicability and usefulness: insights from the Polish adaptation

    Directory of Open Access Journals (Sweden)

    Krzysztof eCipora

    2015-11-01

    Full Text Available Math anxiety has an important impact on mathematical development and performance. However, although math anxiety is supposed to be a transcultural trait, assessment instruments are scarce and are validated mainly for Western cultures so far. Therefore, we aimed at examining the transcultural generality of math anxiety by a thorough investigation of the validity of math anxiety assessment in Eastern Europe. We investigated the validity and reliability of a Polish adaptation of the Abbreviated Math Anxiety Scale (AMAS, known to have very good psychometric characteristics in its original, American-English version as well as in its Italian and Iranian adaptations.We also observed high reliability, both for internal consistency and test-retest stability of the AMAS in the Polish sample. The results also show very good construct, convergent and discriminant validity: The factorial structure in Polish adult participants (n = 857 was very similar to the one previously found in other samples; AMAS scores correlated moderately in expected directions with state and trait anxiety, self-assessed math achievement and skill as well temperamental traits of emotional reactivity, briskness, endurance and perseverance. Average scores obtained by participants as well as gender differences and correlations with external measures were also similar across cultures. Beyond the cultural comparison, we used path model analyses to show that math anxiety relates to math grades and self-competence when controlling for trait anxiety.The current study shows transcultural validity of math anxiety assessment with the AMAS.

  5. Math starters 5- to 10-minute activities aligned with the common core math standards, grades 6-12

    CERN Document Server

    Muschla, Judith A; Muschla, Erin

    2013-01-01

    A revised edition of the bestselling activities guide for math teachers Now updated with new math activities for computers and mobile devices-and now organized by the Common Core State Standards-this book includes more than 650 ready-to-use math starter activities that get kids quickly focused and working as soon as they enter the classroom. Ideally suited for any math curriculum, these high-interest problems spark involvement in the day's lesson, help students build skills, and allow teachers to handle daily management tasks without wasting valuable instructional time. A newly updated edit

  6. Math Anxiety Assessment with the Abbreviated Math Anxiety Scale: Applicability and Usefulness: Insights from the Polish Adaptation.

    Science.gov (United States)

    Cipora, Krzysztof; Szczygieł, Monika; Willmes, Klaus; Nuerk, Hans-Christoph

    2015-01-01

    Math anxiety has an important impact on mathematical development and performance. However, although math anxiety is supposed to be a transcultural trait, assessment instruments are scarce and are validated mainly for Western cultures so far. Therefore, we aimed at examining the transcultural generality of math anxiety by a thorough investigation of the validity of math anxiety assessment in Eastern Europe. We investigated the validity and reliability of a Polish adaptation of the Abbreviated Math Anxiety Scale (AMAS), known to have very good psychometric characteristics in its original, American-English version as well as in its Italian and Iranian adaptations. We also observed high reliability, both for internal consistency and test-retest stability of the AMAS in the Polish sample. The results also show very good construct, convergent and discriminant validity: The factorial structure in Polish adult participants (n = 857) was very similar to the one previously found in other samples; AMAS scores correlated moderately in expected directions with state and trait anxiety, self-assessed math achievement and skill as well temperamental traits of emotional reactivity, briskness, endurance, and perseverance. Average scores obtained by participants as well as gender differences and correlations with external measures were also similar across cultures. Beyond the cultural comparison, we used path model analyses to show that math anxiety relates to math grades and self-competence when controlling for trait anxiety. The current study shows transcultural validity of math anxiety assessment with the AMAS.

  7. Senescent intervertebral disc cells exhibit perturbed matrix homeostasis phenotype.

    Science.gov (United States)

    Ngo, Kevin; Patil, Prashanti; McGowan, Sara J; Niedernhofer, Laura J; Robbins, Paul D; Kang, James; Sowa, Gwendolyn; Vo, Nam

    2017-09-01

    Aging greatly increases the risk for intervertebral disc degeneration (IDD) as a result of proteoglycan loss due to reduced synthesis and enhanced degradation of the disc matrix proteoglycan (PG). How disc matrix PG homeostasis becomes perturbed with age is not known. The goal of this study is to determine whether cellular senescence is a source of this perturbation. We demonstrated that disc cellular senescence is dramatically increased in the DNA repair-deficient Ercc1 -/Δ mouse model of human progeria. In these accelerated aging mice, increased disc cellular senescence is closely associated with the rapid loss of disc PG. We also directly examine PG homeostasis in oxidative damage-induced senescent human cells using an in vitro cell culture model system. Senescence of human disc cells treated with hydrogen peroxide was confirmed by growth arrest, senescence-associated β-galactosidase activity, γH2AX foci, and acquisition of senescence-associated secretory phenotype. Senescent human disc cells also exhibited perturbed matrix PG homeostasis as evidenced by their decreased capacity to synthesize new matrix PG and enhanced degradation of aggrecan, a major matrix PG. of the disc. Our in vivo and in vitro findings altogether suggest that disc cellular senescence is an important driver of PG matrix homeostatic perturbation and PG loss. Published by Elsevier B.V.

  8. Human disc degeneration is associated with increased MMP 7 expression.

    Science.gov (United States)

    Le Maitre, C L; Freemont, A J; Hoyland, J A

    2006-01-01

    During intervertebral disc (IVD) degeneration, normal matrix synthesis decreases and degradation of disc matrix increases. A number of proteases that are increased during disc degeneration are thought to be involved in its pathogenesis. Matrix metalloproteinase 7 (MMP 7) (Matrilysin, PUMP-1) is known to cleave the major matrix molecules found within the IVD, i.e., the proteoglycan aggrecan and collagen type II. To date, however, it is not known how its expression changes with degeneration or its exact location. We investigated the localization of MMP 7 in human, histologically graded, nondegenerate, degenerated and prolapsed discs to ascertain whether MMP 7 is up-regulated during disc degeneration. Samples of human IVD tissue were fixed in neutral buffered formalin, embedded in paraffin, and sections stained with hematoxylin and eosin to score the degree of morphological degeneration. Immunohistochemistry was performed to localize MMP 7 in 41 human IVDs with varying degrees of degeneration. We found that the chondrocyte-like cells of the nucleus pulposus and inner annulus fibrosus were MMP 7 immunopositive; little immunopositivity was observed in the outer annulus. Nondegenerate discs showed few immunopositive cells. A significant increase in the proportion of MMP 7 immunopositive cells was seen in the nucleus pulposus of discs classified as showing intermediate levels of degeneration and a further increase was seen in discs with severe degeneration. Prolapsed discs showed more MMP 7 immunopositive cells compared to nondegenerated discs, but fewer than those seen in cases of severe degeneration.

  9. Exposing the Myth: Advanced Math Does Not Increase Drop out Rates. Math Works

    Science.gov (United States)

    Achieve, Inc., 2013

    2013-01-01

    A common argument against raising math course-taking requirements for all students is that it will cause more students to drop out of high school. But most students who drop out for academic reasons do so not because they are being "too challenged," but rather because they are not being challenged enough. It is important to raise the rigor and…

  10. How Effective Are Community College Remedial Math Courses for Students with the Lowest Math Skills?

    Science.gov (United States)

    Xu, Di; Dadgar, Mina

    2018-01-01

    Objective: This article examines the effectiveness of remediation for community college students who are identified as having the lowest skills in math. Method: We use transcript data from a state community college system and take advantage of a regression discontinuity design that compares statistically identical students who are assigned to the…

  11. Math Teachers' Attitudes towards Photo Math Application in Solving Mathematical Problem Using Mobile Camera

    Science.gov (United States)

    Hamadneh, Iyad M.; Al-Masaeed, Aslan

    2015-01-01

    This study aimed at finding out mathematics teachers' attitudes towards photo math application in solving mathematical problems using mobile camera; it also aim to identify significant differences in their attitudes according to their stage of teaching, educational qualifications, and teaching experience. The study used judgmental/purposive…

  12. Placing Math Reform: Locating Latino English Learners in Math Classrooms and Communities

    Science.gov (United States)

    Erbstein, Nancy

    2015-01-01

    This article explores how place matters in public school reform efforts intended to promote more equitable opportunities and outcomes. Qualitative case studies of three California middle schools' eighth grade math reforms and the resulting opportunities for Latino English learners are presented, using the conceptual frameworks of critical human…

  13. Mechanoreceptors in Diseased Cervical Intervertebral Disc and Vertigo.

    Science.gov (United States)

    Yang, Liang; Yang, Cheng; Pang, Xiaodong; Li, Duanming; Yang, Hong; Zhang, Xinwu; Yang, Yi; Peng, Baogan

    2017-04-15

    We collected the samples of cervical intervertebral discs from patients with vertigo to examine the distribution and types of mechanoreceptors in diseased cervical disc. The aim of this study was to determine whether mechanoreceptors are distributed more abundantly in cervical discs from patients with cervical spondylosis, and whether they are related to vertigo. Previous limited studies have found that normal cervical intervertebral discs are supplied with mechanoreceptors that have been considered responsible for proprioceptive functions. Several clinical studies have indicated that the patients with cervical spondylosis manifested significantly impaired postural control and subjective balance disturbance. We collected 77 samples of cervical discs from 62 cervical spondylosis patients without vertigo, 61 samples from 54 patients with vertigo, and 40 control samples from 8 cadaveric donors to investigate distribution of mechanoreceptors containing neurofilament (NF200) and S-100 protein immunoreactive nerve endings. The immunohistochemical investigation revealed that the most frequently encountered mechanoreceptors were the Ruffini corpuscles in all groups of cervical disc samples. They were obviously increased in the number and deeply ingrown into inner annulus fibrosus and even into nucleus pulposus in the diseased cervical discs from patients with vertigo in comparison with the discs from patients without vertigo and control discs. Only three Golgi endings were seen in the three samples from patients with vertigo. No Pacinian corpuscles were found in any samples of cervical discs. The diseased cervical discs from patients with vertigo had more abundant distribution of Ruffini corpuscles than other discs. A positive association between the increased number and ingrowth of Ruffini corpuscles in the diseased cervical disc and the incidence of vertigo in the patients with cervical spondylosis was found, which may indicate a key role of Ruffini corpuscles in the

  14. Total disc replacement using tissue-engineered intervertebral discs in the canine cervical spine.

    Directory of Open Access Journals (Sweden)

    Yu Moriguchi

    Full Text Available The most common reason that adults in the United States see their physician is lower back or neck pain secondary to degenerative disc disease. To date, approaches to treat degenerative disc disease are confined to purely mechanical devices designed to either eliminate or enable flexibility of the diseased motion segment. Tissue engineered intervertebral discs (TE-IVDs have been proposed as an alternative approach and have shown promise in replacing native IVD in the rodent tail spine. Here we demonstrate the efficacy of our TE-IVDs in the canine cervical spine. TE-IVD components were constructed using adult canine annulus fibrosis and nucleus pulposus cells seeded into collagen and alginate hydrogels, respectively. Seeded gels were formed into a single disc unit using molds designed from the geometry of the canine spine. Skeletally mature beagles underwent discectomy with whole IVD resection at levels between C3/4 and C6/7, and were then divided into two groups that received only discectomy or discectomy followed by implantation of TE-IVD. Stably implanted TE-IVDs demonstrated significant retention of disc height and physiological hydration compared to discectomy control. Both 4-week and 16-week histological assessments demonstrated chondrocytic cells surrounded by proteoglycan-rich matrices in the NP and by fibrocartilaginous matrices in the AF portions of implanted TE-IVDs. Integration into host tissue was confirmed over 16 weeks without any signs of immune reaction. Despite the significant biomechanical demands of the beagle cervical spine, our stably implanted TE-IVDs maintained their position, structure and hydration as well as disc height over 16 weeks in vivo.

  15. Essential maths for geoscientists an introduction

    CERN Document Server

    Palmer, Paul I

    2014-01-01

    Maths for Geoscientists is an accessible, student-friendly introduction to the essential mathematics required by those students taking degree courses within the Geosciences. Clearly structured throughout, this book carefully guides the student step by step through the mathematics they will encounter and will provide numerous applied examples throughout to enhance students understanding and to place each technique into context. Opening with a chapter explaining the need for studying mathematics within geosciences the book then moves on to cover algebra, equations, solutions, logarithms and ex

  16. MhicMathúna v Ireland

    OpenAIRE

    Thornton, Liam

    2016-01-01

    This is a feminist re-imagining of the Supreme Court decision MhicMathúna v Ireland [1995] 1 I.R. 454. The actual Supreme Court decision in this case continues to have a profound impact upon how the Irish superior courts view constitutional socio-economic rights claims. This feminist judgment seeks to re-situate the legal analysis of constitutionalised socio-economic rights claims. However, this, as is seen from the feminist judgment, has not been an easy task. The plaintiffs' in this case at...

  17. Suspected herniated lumbar disc - computed tomography in differential diagnosis of non-disc-related sciatica

    International Nuclear Information System (INIS)

    Weiss, T.; Koehler, D.; Treisch, J.; Claussen, C.; Felix, R.

    1984-01-01

    The most common reason a patient is referred for spinal CT examination is to exclude a ruptured intervertebral disc. Besides nerve root entrapment due to herniated disc, a number of unusual for unexpected conditions have been encountered in the course of CT lumbar spine studies. These include spondylolisthesis, spinal dysraphism, Paget's disease, and inflammatory, neoplastic, or metastatic lesions. The application of spinal (small-circle) target imaging includes the risk to overlook soft tissue lesions that extend beyond the reconstruction circle. Therefore, complete (large-circle) circumferential abdominal scanning is recommended in case of a suspected extraspinal cause of sciatica. (orig.) [de

  18. Suspected herniated lumbar disc - computed tomography in differential diagnosis of non-disc-related sciatica

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, T.; Koehler, D.; Treisch, J.; Claussen, C.; Felix, R.

    1984-07-01

    The most common reason a patient is referred for spinal CT examination is to exclude a ruptured intervertebral disc. Besides nerve root entrapment due to herniated disc, a number of unusual or unexpected conditions have been encountered in the course of CT lumbar spine studies. These include spondylolisthesis, spinal dysraphism, Paget's disease, and inflammatory, neoplastic, or metastatic lesions. The application of spinal (small-circle) target imaging includes the risk of overlooking soft tissue lesions that extend beyond the reconstruction circle. Therefore, complete (large-circle) circumferential abdominal scanning is recommended in case of a suspected extraspinal cause of sciatica.

  19. Evaluating Number Sense in Community College Developmental Math Students

    Science.gov (United States)

    Steinke, Dorothea A.

    2017-01-01

    Community college developmental math students (N = 657) from three math levels were asked to place five whole numbers on a line that had only endpoints 0 and 20 marked. How the students placed the numbers revealed the same three stages of behavior that Steffe and Cobb (1988) documented in determining young children's number sense. 23% of the…

  20. Do the Math: Course Redesign's Impact on Learning and Scheduling

    Science.gov (United States)

    Squires, John; Faulkner, Jerry; Hite, Carl

    2009-01-01

    The math department at Cleveland State Community College embarked upon course redesign in 2008. As a result of this project, student engagement, learning, and success rates have increased dramatically. By including both developmental and college level math courses in the redesign, the department has been able to implement innovative scheduling and…

  1. Classroom Environment, Achievement Goals and Maths Performance: Gender Differences

    Science.gov (United States)

    Gherasim, Loredana Ruxandra; Butnaru, Simona; Mairean, Cornelia

    2013-01-01

    This study investigated how gender shapes the relationships between classroom environment, achievement goals and maths performance. Seventh-grade students ("N"?=?498) from five urban secondary schools filled in achievement goal orientations and classroom environment scales at the beginning of the second semester. Maths performance was…

  2. Math and Economics: Implementing Authentic Instruction in Grades K-5

    Science.gov (United States)

    Althauser, Krista; Harter, Cynthia

    2016-01-01

    The purpose of this study is to outline a partnership program that involved a local elementary school district, an institution of higher education, the local business community, and a state economic education advocacy group to integrate economics into math in grades K-5. The "Economics: Math in Real Life" program was provided in…

  3. Math on MXit: the medium is the message

    CSIR Research Space (South Africa)

    Butgereit, L

    2007-07-01

    Full Text Available Homework is a necessary evil in the path of learning mathematics at school. Mathematics homework is traditionally seen as difficult and boring. In the case of difficult homework, “math clubs” and “math extra lessons” are often perceived as even more...

  4. Determinants of Grades in Maths for Students in Economics

    DEFF Research Database (Denmark)

    Cappellari, Lorenzo; Lucifora, Claudio; Pozzoli, Dario

    attended are signi cantly associated with maths grades. Ceteris paribus, females typically do better than males. Since students can postpone the exam or repeat it when they fail, we also analyze the determinants of the elapsed time to pass the exam using survival analysis. Modeling simultaneously maths...

  5. How Math Anxiety Relates to Number–Space Associations

    Science.gov (United States)

    Georges, Carrie; Hoffmann, Danielle; Schiltz, Christine

    2016-01-01

    Given the considerable prevalence of math anxiety, it is important to identify the factors contributing to it in order to improve mathematical learning. Research on math anxiety typically focusses on the effects of more complex arithmetic skills. Recent evidence, however, suggests that deficits in basic numerical processing and spatial skills also constitute potential risk factors of math anxiety. Given these observations, we determined whether math anxiety also depends on the quality of spatial-numerical associations. Behavioral evidence for a tight link between numerical and spatial representations is given by the SNARC (spatial-numerical association of response codes) effect, characterized by faster left-/right-sided responses for small/large digits respectively in binary classification tasks. We compared the strength of the SNARC effect between high and low math anxious individuals using the classical parity judgment task in addition to evaluating their spatial skills, arithmetic performance, working memory and inhibitory control. Greater math anxiety was significantly associated with stronger spatio-numerical interactions. This finding adds to the recent evidence supporting a link between math anxiety and basic numerical abilities and strengthens the idea that certain characteristics of low-level number processing such as stronger number–space associations constitute a potential risk factor of math anxiety. PMID:27683570

  6. Brief Report: Gum Chewing Affects Standardized Math Scores in Adolescents

    Science.gov (United States)

    Johnston, Craig A.; Tyler, Chermaine; Stansberry, Sandra A.; Moreno, Jennette P.; Foreyt, John P.

    2012-01-01

    Gum chewing has been shown to improve cognitive performance in adults; however, gum chewing has not been evaluated in children. This study examined the effects of gum chewing on standardized test scores and class grades of eighth grade math students. Math classes were randomized to a gum chewing (GC) condition that provided students with gum…

  7. The Math Promise: Celebrating at Home and School

    Science.gov (United States)

    Legnard, Danielle; Austin, Susan

    2014-01-01

    The Math Promise is a contract that family members make with one another. They commit to spending mathematical time together; getting to know each other's mathematical thinking and understanding; and finding time to play math games, solve problems, and notice mathematics in their daily lives. Whether parents and children are cooking in the…

  8. Feedback Design Patterns for Math Online Learning Systems

    Science.gov (United States)

    Inventado, Paul Salvador; Scupelli, Peter; Heffernan, Cristina; Heffernan, Neil

    2017-01-01

    Increasingly, computer-based learning systems are used by educators to facilitate learning. Evaluations of several math learning systems show that they result in significant student learning improvements. Feedback provision is one of the key features in math learning systems that contribute to its success. We have recently been uncovering feedback…

  9. An Integration of Math with Auto Technician Courses

    Science.gov (United States)

    Valenzuela, Hector

    2012-01-01

    This article describes the development of the contextualized math, the course design, student teaching and daily interaction with the students, and the implementation aspects of the research project designed to develop contextualized mathematics and integrate it into the Auto Technician courses. The applied math curriculum was integrated into…

  10. HeartMath and Ubuntu integral healing approaches for social ...

    African Journals Online (AJOL)

    HeartMath and Ubuntu integral healing approaches for social coherence and physical activity. Stephen D. Edwards. Abstract. This research was motivated by many social health problems confronting planet earth. Its aim is to introduce HeartMath and Ubuntu as complimentary, integral healing approaches for promoting ...

  11. Science and Math in the Library Media Center Using GLOBE.

    Science.gov (United States)

    Aquino, Teresa L.; Levine, Elissa R.

    2003-01-01

    Describes the Global Learning and Observations to Benefit the Environment (GLOBE) program which helps school library media specialists and science and math teachers bring earth science, math, information literacy, information technology, and student inquiry into the classroom. Discusses use of the Internet to create a global network to study the…

  12. Restructuring Schools To Be Math Friendly to Females.

    Science.gov (United States)

    Karp, Karen; Shakeshaft, Charol

    1997-01-01

    The gender gap in math Scholastic Aptitude Test scores, attributable to course avoidance, lack of confidence, and unbalanced classroom instruction, can have serious consequences for young women, such as limited university selection, limited career choices, and lower lifetime salaries. Solutions include hiring math specialists, establishing role…

  13. Math Garden: A new educational and scientific instrument

    NARCIS (Netherlands)

    Straatemeier, M.

    2014-01-01

    This dissertation describes the research concerning the construction of a new educational and scientific instrument. This instrument, Math Garden, is a web application in which children can practice arithmetic by playing math games in which items are tailored to their ability level. At the same

  14. Basic Math Skills and Performance in an Introductory Economics Class

    Science.gov (United States)

    Ballard, Charles L.; Johnson, Marianne F.

    2004-01-01

    The authors measure math skills with a broader set of explanatory variables than have been used in previous studies. To identify what math skills are important for student success in introductory microeconomics, they examine (1) the student's score on the mathematics portion of the ACT Assessment Test, (2) whether the student has taken calculus,…

  15. Why Aren't More Minorities Taking Advanced Math?

    Science.gov (United States)

    Walker, Erica N.

    2007-01-01

    Black and Latino students are still underepresented in upper-level math classes in the United States, a fact which has serious implications for their academic achievement and futures. Walker provides six suggestions for how educators can encourage more black and Latino students to successfully take higher level math courses: (1) Expand our…

  16. How math anxiety relates to number-space associations

    Directory of Open Access Journals (Sweden)

    Carrie Georges

    2016-09-01

    Full Text Available Given the considerable prevalence of math anxiety, it is important to identify the factors contributing to it in order to improve mathematical learning. Research on math anxiety typically focusses on the effects of more complex arithmetic skills. Recent evidence, however, suggests that deficits in basic numerical processing and spatial skills also constitute potential risk factors of math anxiety. Given these observations, we determined whether math anxiety also depends on the quality of spatial-numerical associations. Behavioural evidence for a tight link between numerical and spatial representations is given by the SNARC (spatial-numerical association of response codes effect, characterized by faster left-/right-sided responses for small/large digits respectively in binary classification tasks. We compared the strength of the SNARC effect between high and low math anxious individuals using the classical parity judgment task in addition to evaluating their spatial skills, arithmetic performance, working memory and inhibitory control. Greater math anxiety was significantly associated with stronger spatio-numerical interactions. This finding adds to the recent evidence supporting a link between math anxiety and basic numerical abilities and strengthens the idea that certain characteristics of low-level number processing such as stronger number-space associations constitute a potential risk factor of math anxiety.

  17. Effects of Math Anxiety on Student Success in Higher Education

    Science.gov (United States)

    Nunez-Pena, M. I.; Suarez-Pellicioni, M.; Bono, R.

    2013-01-01

    This study examines whether math anxiety and negative attitudes toward mathematics have an effect on university students' academic achievement in a methodological course forming part of their degree. A total of 193 students were presented with a math anxiety test and some questions about their enjoyment, self-confidence and motivation regarding…

  18. The Effect of Cooperative Groups on Math Anxiety

    Science.gov (United States)

    Batton, Melissa

    2010-01-01

    Research indicates that many students have difficulty with mathematics, which can be attributed to many factors including math anxiety. Students who experience math anxiety have poor attitudes towards mathematics and perform below grade level based on class and statewide assessments. The purpose of this quasi-experimental quantitative study was to…

  19. How Math Anxiety Relates to Number-Space Associations.

    Science.gov (United States)

    Georges, Carrie; Hoffmann, Danielle; Schiltz, Christine

    2016-01-01

    Given the considerable prevalence of math anxiety, it is important to identify the factors contributing to it in order to improve mathematical learning. Research on math anxiety typically focusses on the effects of more complex arithmetic skills. Recent evidence, however, suggests that deficits in basic numerical processing and spatial skills also constitute potential risk factors of math anxiety. Given these observations, we determined whether math anxiety also depends on the quality of spatial-numerical associations. Behavioral evidence for a tight link between numerical and spatial representations is given by the SNARC (spatial-numerical association of response codes) effect, characterized by faster left-/right-sided responses for small/large digits respectively in binary classification tasks. We compared the strength of the SNARC effect between high and low math anxious individuals using the classical parity judgment task in addition to evaluating their spatial skills, arithmetic performance, working memory and inhibitory control. Greater math anxiety was significantly associated with stronger spatio-numerical interactions. This finding adds to the recent evidence supporting a link between math anxiety and basic numerical abilities and strengthens the idea that certain characteristics of low-level number processing such as stronger number-space associations constitute a potential risk factor of math anxiety.

  20. Metacognitive Awareness and Math Anxiety in Gifted Students

    Science.gov (United States)

    Saricam, Hakan; Ogurlu, Üzeyir

    2015-01-01

    The basic purpose of this study has been to examine the relationships between metacognitive awareness and maths anxiety in gifted students. The second aim was to compare with gifted and non-gifted students' metacognitive awareness and maths anxiety levels. The participants were 300 (150 gifted, 150 non-gifted) volunteer secondary school students…

  1. Remediation of Math Anxiety in Preservice Elementary School Teachers

    Science.gov (United States)

    Dunkle, Susan M.

    2010-01-01

    The purpose of this study was to measure the level of math anxiety in preservice elementary teachers, and then to determine if remediation methods would lower the measured level of anxiety in these same preservice teachers. The 10-day study provided an intense remediation using a time-series design to measure change on the Revised Math Anxiety…

  2. Cognitive and Academic Profiles Associated with Math Disability Subtypes

    Science.gov (United States)

    Kubas, Hanna A.; Schmid, Amy D.; Drefs, Michelle A.; Poole, Jennifer M.; Holland, Sara; Fiorello, Catherine A.

    2014-01-01

    Children with math disabilities (MD) represent a heterogeneous group and often display deficits in one or more cognitive domains. Math proficiency requires a number of different cognitive processes, including quantitative knowledge, working memory, processing speed, fluid reasoning, and executive functions. Assessment practices that do not address…

  3. The Reliability of Randomly Generated Math Curriculum-Based Measurements

    Science.gov (United States)

    Strait, Gerald G.; Smith, Bradley H.; Pender, Carolyn; Malone, Patrick S.; Roberts, Jarod; Hall, John D.

    2015-01-01

    "Curriculum-Based Measurement" (CBM) is a direct method of academic assessment used to screen and evaluate students' skills and monitor their responses to academic instruction and intervention. Interventioncentral.org offers a math worksheet generator at no cost that creates randomly generated "math curriculum-based measures"…

  4. Impact of University Lecturers' Intervention in School MathTeaching

    Indian Academy of Sciences (India)

    Some schools in the neighbourhood of Sefako MakgathoHealth Sciences University (SMU) in South Africa persistentlyyielded poor mathematics results in the past years. Thiswas of concern since maths is the main subject for manyopportunities, including admissiontoSMUstudy programmes.Some SMU maths lecturers ...

  5. Math and Science Gateways to California's Fastest Growing Careers

    Science.gov (United States)

    EdSource, 2008

    2008-01-01

    Some students--and parents--think math and science are not too important for their future. As everyday life becomes more dependent on technology, most people will need a better background in math and science to succeed in today's global economy. To get high-paying jobs in some of California's fastest-growing occupations, a strong background in…

  6. Schrödinger evolution of self-gravitating discs

    Science.gov (United States)

    Batygin, Konstantin

    2018-04-01

    An understanding of the long-term evolution of self-gravitating discs ranks among the classic outstanding problems of astrophysics. In this work, we show that the secular inclination dynamics of a geometrically thin quasi-Keplerian disc, with a surface density profile that scales as the inverse square-root of the orbital radius, are described by the time-dependent Schrödinger equation. Within the context of this formalism, nodal bending waves correspond to the eigenmodes of a quasi-particle's wavefunction, confined in an infinite square well with boundaries given by the radial extent of the disc. We further show that external secular perturbations upon self-gravitating discs exhibit a mathematical similarity to quantum scattering theory. Employing this framework, we derive an analytic criterion for the gravitational rigidity of a nearly-Keplerian disc under external perturbations. Applications of the theory to circumstellar discs and Galactic nuclei are discussed.

  7. Evidence for accreted component in the Galactic discs

    Science.gov (United States)

    Xing, Q. F.; Zhao, G.

    2018-06-01

    We analyse the distribution of [Mg/Fe] abundance in the Galactic discs with F- and G-type dwarf stars selected from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) archive. The sample stars are assigned into different stellar populations by using kinematic criteria. Our analysis reveals the chemical inhomogeneities in the Galactic thick disc. A few of metal-poor stars in the thick disc exhibit relatively low [Mg/Fe] abundance in respect to the standard thick-disc sample. The orbital eccentricities and maximum Galactocentric radii of low-α metal-poor stars are apparently greater than that of high-α thick-disc stars. The orbital parameters and chemical components of low-α stars in the thick disc suggest that they may have been formed in regions with low star formation rate that were located at large distances from the Galactic centre, such as infalling dwarf spheroidal galaxies.

  8. Indigenous development of rupture discs for FBTR (Paper No. 028)

    International Nuclear Information System (INIS)

    Chetal, S.C.; Raju, Chander; Anandkumar, V.; Seetharaman, V.

    1987-02-01

    Rupture discs are required as a safety device for protecting the secondary sodium circuit and its components against high pressure surges due to accidental water-steam leaks in sodium heated steam generator and the consequent sodium water reaction. For identical reasons, rupture discs are also required on the vessels used for decontamination of sodium components. As an import substitution of the costly items for the FBTR Project, development of the rupture disc assemblies has been in progress at Indira Gandhi Centre for Atomic Research, Kalpakkam. Reverse buckling knife blade concept with stainless steel disc has been taken up for development. Hydroforming process without any die has been selected for disc fabrication. One rupture disc assembly required for steam generator has been tested in sodium satisfactorily. (author). 4 tables, 5 figs

  9. Membangun Karakter Anak Usia Dini melalui Pembelajaran Math Character

    Directory of Open Access Journals (Sweden)

    Titin Faridatun Nisa’

    2016-09-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui penerapan pembelajaran math character untuk membangun karakter Anak Usia Dini (AUD dan kesulitan-kesulitan yang dialami guru dalam penerapan pembelajaran math character. Target penelitian ini adalah terbentuknya karakter anak usia dini melalui pembelajaran math character. Jenis penelitian ini adalah penelitian deskriptif dengan metode penelitian kualitatif. Teknik pengumpulan informasi penelitian ini dengan metode observasi dan wawancara. Analisis data penelitian ini menggunakan analisis deskriptif. Hasil penelitian menunjukkan bahwa penerapan pembelajaran math character dapat membangun delapan belas nilai-nilai karakter AUD. Kesulitan-kesulitan yang dialami guru dalam pembentukan karakter AUD melalui pembelajaran math character meliputi tema yang digunakan termasuk tema baru, siswa belum terbiasa dengan pembelajaran berbasis sentra, usia siswa bervariasi, dan adanya ikut campur wali siswa dalam kegiatan pembelajaran di kelas sehingga siswa menjadi kurang mandiri.

  10. On P-weight and P-distance inequalities

    DEFF Research Database (Denmark)

    Britz, Thomas Johann

    2006-01-01

    Jang and Park asked in [On a MacWilliams type identity and a perfectness for a binary linear (n, n - 1, j)-poset code, Discrete Math. 265 (2003) 85-104] whether, for each poset P = {l...., n}, the P-weights and P-distances satisfy the inequalities w(P)(x) - w(P)(y)......Jang and Park asked in [On a MacWilliams type identity and a perfectness for a binary linear (n, n - 1, j)-poset code, Discrete Math. 265 (2003) 85-104] whether, for each poset P = {l...., n}, the P-weights and P-distances satisfy the inequalities w(P)(x) - w(P)(y)...

  11. Math anxiety differentially affects WAIS-IV arithmetic performance in undergraduates.

    Science.gov (United States)

    Buelow, Melissa T; Frakey, Laura L

    2013-06-01

    Previous research has shown that math anxiety can influence the math performance level; however, to date, it is unknown whether math anxiety influences performance on working memory tasks during neuropsychological evaluation. In the present study, 172 undergraduate students completed measures of math achievement (the Math Computation subtest from the Wide Range Achievement Test-IV), math anxiety (the Math Anxiety Rating Scale-Revised), general test anxiety (from the Adult Manifest Anxiety Scale-College version), and the three Working Memory Index tasks from the Wechsler Adult Intelligence Scale-IV Edition (WAIS-IV; Digit Span [DS], Arithmetic, Letter-Number Sequencing [LNS]). Results indicated that math anxiety predicted performance on Arithmetic, but not DS or LNS, above and beyond the effects of gender, general test anxiety, and math performance level. Our findings suggest that math anxiety can negatively influence WAIS-IV working memory subtest scores. Implications for clinical practice include the utilization of LNS in individuals expressing high math anxiety.

  12. Cervical artificial disc extrusion after a paragliding accident

    OpenAIRE

    Niu, Tianyi; Hoffman, Haydn; Lu, Daniel C.

    2017-01-01

    Background: Cervical total disc replacement (TDR) is an established alternative to anterior cervical discectomy and fusion (ACDF) with excellent long-term outcomes and low failure rates. Cases of implant failure and migration are scarce and primarily limited to several years postoperatively. The authors report a case of anterior extrusion of a C4-C5 ProDisc-C (DePuy Synthes, West Chester, PA, USA) cervical artificial disc (CAD) 14 months after placement due to minor trauma. Case Description: ...

  13. Thoracic spine disc-related abnormalities: longitudinal MR imaging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Charles J.; Schweitzer, Mark E.; Morrison, William B.; Parellada, Joan A. [TJUH Radiology, Philadelphia, Pennsylvania (United States); Carrino, J.A. [Department of Radiology ASB-1, Harvard Medical School, Brigham and Women' s Hospital, L1, Room 002B, 75 Francis Street, MA 02115, Boston (United States)

    2004-04-01

    To describe and characterize the temporal changes in disc-related disorders of the thoracic spine using MR imaging. A retrospective longitudinal cohort study was carried out of 40 patients with two sequential thoracic spine MR images at variable intervals. The images were assessed for baseline presence of, new incidence of and changes in disc herniation, degenerative disc disease, endplate marrow signal alteration and Schmorl nodes. The range of follow-up was 4-149 weeks. Baseline presence was: disc herniation, 10% (49/480); degenerative disc disease, 14% (66/480); endplate marrow signal alteration, 2.3% (11/480); Schmorl nodes 9.6% (46/480). Most pre-existing lesions tended to remain unchanged. Herniations showed the most change, tending to improve in 27%. New incidence was: disc herniation, 1.5% (7/480), degenerative disc disease, 2% (10/480); endplate marrow signal alteration, 1.6% (8/480); Schmorl nodes, 2.1% (10/480). Disc degeneration was first visible at an 11-week interval and once established almost never changed over many weeks to months. Endplate signal alterations (Modic changes) were uncommon. Schmorl nodes show no change from baseline for up to 2 1/2 years. All findings predominated in the lower intervertebral levels from T6 to T10. The most prevalent thoracic spine disc-related findings are degeneration and herniation. Disc herniations predominate in the lower segments and are a dynamic phenomenon. Disc degeneration can be rapidly evolving but tends to remain unchanged after occurrence. Endplate marrow signal changes were an uncommon manifestation of thoracic disc disease. Schmorl nodes showed the least change over time. (orig.)

  14. Collimation of particle beams from thick accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M [N. Copernicus Astronomical Center, Warszawa (Poland); Wilson, D B [Cambridge Univ. (UK). Inst. of Astronomy

    1981-11-01

    The acceleration and collimation of particle beams in the funnel of thick accretion discs is studied in the approximation that the flow is optically thin. Such flows can be collimated to within approximately 0.1 radians by sufficiently thick discs. The flow cannot convert more than a small fraction of the disc's (super-Eddington) luminosity into the energy flow of a narrow beam without being optically thick.

  15. New Brown Dwarf Discs in Upper Scorpius Observed with WISE

    Science.gov (United States)

    Dawson, P.; Scholz, A.; Ray, T. P.; Natta, A.; Marsh, K. A.; Padgett, D.; Ressler, M. E.

    2013-01-01

    We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10 Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour magnitude and colour colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19 per cent) lack excess at 3.4 and 4.6 microns and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars.We estimate that the time-scale for a typical transition from class II to class III is less than 0.4 Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5 10 Myr and a disc clearing time-scale significantly shorter than 1 Myr.

  16. Math for scientists refreshing the essentials

    CERN Document Server

    Maurits, Natasha

    2017-01-01

    Accessible and comprehensive, this guide is an indispensable tool for anyone in the sciences – new and established researchers, students and scientists – looking either to refresh their math skills or to prepare for the broad range of math, statistical and data-related challenges they are likely to encounter in their work or studies. In addition to helping scientists improve their knowledge of key mathematical concepts, this unique book will help readers: ·                     Read mathematical symbols ·                     Understand formulas, data or statistical information ·                     Determine medication equivalents ·                     Analyze neuroimaging  Mathematical concepts are presented alongside illustrative and useful real-world scien­tific examples and are further clarified through practical pen-and-paper exercises. Whether you are a student encountering high-level mathematics in your research or...

  17. PUMAS: Practical Uses of Math And Science

    Science.gov (United States)

    Kahn, R. A.

    2009-12-01

    For more than ten years, PUMAS has provided a forum for disseminating peer-reviewed examples of Practical Uses of Math And Science, aimed at helping pre-college teachers enrich their presentation of math and science topics. Contributors include scientists, engineers, and content experts from many disciplines. The innovative ideas in PUMAS examples tend to be treasures, containing the ‘sparks’ of understanding that comes only from having real-life experience with the material. Examples can be essays, anecdotes, problems, demonstrations, or activities, and can be written in any style that serves the material well. They are keyed to the National Standards and Benchmarks, which provide the critical connection to K-12 curriculum guidelines, and the peer-review process involves at least one scientist with a relevant background, and at least one teacher at an appropriate grade level. The PUMAS Web Site has recently been upgraded. It is now a NASA-wide facility, recognized by both the National Science Teachers Association (NSTA) and the National Council of Teachers of Mathematics (NCTM). This presentation will describe and illustrate the operation of PUMAS, will highlight a few of our many treasures, and will appeal to scientists interested in contributing meaningfully to pre-college education to consider submitting examples to PUMAS.

  18. Imagine math 3 between culture and mathematics

    CERN Document Server

    2015-01-01

    Imagine mathematics, imagine with the help of mathematics, imagine new worlds, new geometries, new forms. This volume in the series “Imagine Math” casts light on what is new and interesting in the relationships between mathematics, imagination, and culture. The book opens by examining the connections between modern and contemporary art and mathematics, including Linda D. Henderson’s contribution. Several further papers are devoted to mathematical models and their influence on modern and contemporary art, including the work of Henry Moore and Hiroshi Sugimoto. Among the many other interesting contributions are an homage to Benoît Mandelbrot with reference to the exhibition held in New York in 2013 and the thoughts of Jean-Pierre Bourguignon on the art and math exhibition at the Fondation Cartier in Paris. An interesting part is dedicated to the connections between math, computer science and theatre with the papers by C. Bardainne and A. Mondot.  The topics are treated in a way that is rigorous but capt...

  19. Maths and physics, a love story

    CERN Multimedia

    CERN Bulletin

    Denis Guedj brings one of his plays to CERN. The writer and mathematician is working on a new novel in which LHC research figures prominently. In Denis Guedj’s plays, the number One is a self-absorbed character, Zero is not to be underestimated, and the Line Segment wants the Curve to straighten out. In his novels, mathematical entities come to life—and turn out to have exciting stories to tell. Denis Guedj is a mathematician and professor of the history of science and epistemology at the University of Paris VIII; over the years he has also indulged a personal passion for bringing maths to the stage. His novels and plays reach a broad public. Among his notable successes is a crime thriller called “The Parrot’s Theorem”, which has been translated into 20 languages. The popularity of his work owes much to the author’s refusal to be didactic. “If it works, it’s because I don’t try to teach maths,” he explains....

  20. Preschool Math Exposure in Private Center-Based Care and Low-SES Children's Math Development

    Science.gov (United States)

    Bachman, Heather J.; Degol, Jessica L.; Elliott, Leanne; Scharphorn, Laura; El Nokali, Nermeen E.; Palmer, Kalani M.

    2018-01-01

    Research Findings: The present study examined the amount of exposure to math activities that children of low socioeconomic status (SES) encounter in private community-based preschool classrooms and whether greater time in these activities predicted higher math skills. Three cohorts of 4- to 5-year-old children were recruited from 30 private…

  1. Instant Math Storymats with Hands-on Activities for Building Essential Primary Math Skills, Grades K-2.

    Science.gov (United States)

    Spann, Mary Beth

    This book contains 18 reproducible Math Storymats which can be a refreshing addition to any early elementary math program. Each storymat is accompanied by two separate read-aloud story selections that guide children in using plastic disk-shaped markers to interact with the mats in specific and open-ended ways. Together the mats and the…

  2. Carnegie Math Pathways 2015-2016 Impact Report: A Five-Year Review. Carnegie Math Pathways Technical Report

    Science.gov (United States)

    Hoang, Hai; Huang, Melrose; Sulcer, Brian; Yesilyurt, Suleyman

    2017-01-01

    College math is a gateway course that has become a constraining gatekeeper for tens of thousands of students annually. Every year, over 500,000 students fail developmental mathematics, preventing them from achieving their college and career goals. The Carnegie Math Pathways initiative offers students an alternative. It comprises two Pathways…

  3. Math Academy: Play Ball! Explorations in Data Analysis & Statistics. Book 3: Supplemental Math Materials for Grades 3-8

    Science.gov (United States)

    Rimbey, Kimberly

    2008-01-01

    Created by teachers for teachers, the Math Academy tools and activities included in this booklet were designed to create hands-on activities and a fun learning environment for the teaching of mathematics to the students. This booklet contains the "Math Academy--Play Ball! Explorations in Data Analysis & Statistics," which teachers can use to…

  4. Math Academy: Let's Go to the Mall! Explorations in Combinatorics. Book 5: Supplemental Math Materials for Grades 3-8

    Science.gov (United States)

    Rimbey, Kimberly

    2008-01-01

    Created by teachers for teachers, the Math Academy tools and activities included in this booklet were designed to create hands-on activities and a fun learning environment for the teaching of mathematics to the students. This booklet contains the "Math Academy--Let's Go to the Mall! Explorations in Combinatorics," which teachers can use to enhance…

  5. Math Academy: Dining Out! Explorations in Fractions, Decimals, & Percents. Book 4: Supplemental Math Materials for Grades 3-8

    Science.gov (United States)

    Rimbey, Kimberly

    2007-01-01

    Created by teachers for teachers, the Math Academy tools and activities included in this booklet were designed to create hands-on activities and a fun learning environment for the teaching of mathematics to the students. This booklet contains the "Math Academy--Dining Out! Explorations in Fractions, Decimals, and Percents," which teachers can use…

  6. Building a Math-Positive Culture: How to Support Great Math Teaching in Your School (ASCD Arias)

    Science.gov (United States)

    Seeley, Cathy L.

    2016-01-01

    Cathy L. Seeley, former president of the National Council of Teachers of Mathematics, turns the spotlight on administrative leaders who are seeking to improve their math programs, offering an overview of what an effective program looks like and examples of actions to take to achieve that goal. "Building a Math-Positive Culture" addresses…

  7. ISASS Policy Statement – Lumbar Artificial Disc

    Science.gov (United States)

    Garcia, Rolando

    2015-01-01

    Purpose The primary goal of this Policy Statement is to educate patients, physicians, medical providers, reviewers, adjustors, case managers, insurers, and all others involved or affected by insurance coverage decisions regarding lumbar disc replacement surgery. Procedures This Policy Statement was developed by a panel of physicians selected by the Board of Directors of ISASS for their expertise and experience with lumbar TDR. The panel's recommendation was entirely based on the best evidence-based scientific research available regarding the safety and effectiveness of lumbar TDR. PMID:25785243

  8. Frictional Torque on a Rotating Disc

    Science.gov (United States)

    2012-01-01

    Tracker Eur. J. Phys. 33 615–22 [2] Alam J, Hassan H, Shamim S , Mahmood W and Anwar M S 2011 Precise measurement of velocity dependent friction in...on a rotating disc 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) US Naval Academy,Physics Department,Annapolis,MD,21402-1363 8. PERFORMING ORGANIZATION

  9. ISO science - observations of dusty discs.

    Science.gov (United States)

    Heske, A.

    1992-12-01

    ISO, the Infrared Space Observatory, will be an infrared observing facility in space. Via submission of observing proposals, use of this facility will be open to the astronomical community. The scientific payload consists of two spectrometers, a camera and a photo-polarimeter. Following an overview of the ISO mission, this paper describes the highlights of the Central Programme - proposals which are being prepared by the instrument groups, the mission scientists and the astronomers of the ISO Science Operations Team - with special emphasis on the proposals concerned with dusty discs.

  10. Angular Speed of a Compact Disc

    Science.gov (United States)

    Sawicki, Mikolaj ``Mik''

    2006-09-01

    A spinning motion of a compact disc in a CD player offers an interesting and challenging problem in rotational kinematics with a nonconstant angular acceleration that can be incorporated into a typical introductory physics class for engineers and scientists. It can be used either as an example presented during the lecture, emphasizing application of calculus, or as a homework assignment that could be handled easily with the help of a spreadsheet, thus eliminating the calculus aspect altogether. I tried both approaches, and the spreadsheet study was favored by my students.

  11. Power diagrams and interaction processes for unions of discs

    DEFF Research Database (Denmark)

    Møller, Jesper; Helisova, Katarina

    We study a flexible class of finite disc process models with interaction between the discs. We let U denote the random set given by the union of discs, and use for the disc process an exponential family density with the canonical sufficient statistic only depending on geometric properties of U......, becomes useful for handling the problem of edge effects when only U is observed within a bounded observation window. The power tessellation and its dual graph become major tools when establishing inclusion-exclusion formulae, formulae for computing geometric characteristics of U, and stability properties...

  12. Power diagrams and interaction processes for unions of discs

    DEFF Research Database (Denmark)

    Møller, Jesper; Helisova, Katerina

    2008-01-01

     We study a flexible class of finite-disc process models with interaction between the discs. We let U denote the random set given by the union of discs, and use for the disc process an exponential family density with the canonical sufficient statistic depending only on geometric properties of U......, becomes useful for handling the problem of edge effects when only U is observed within a bounded observation window. The power tessellation and its dual graph become major tools when establishing inclusion-exclusion formulae, formulae for computing geometric characteristics of U, and stability properties...

  13. Disc electrophoresis and related techniques of polyacrylamide gel electrophoresis

    National Research Council Canada - National Science Library

    Maurer, H. R

    1971-01-01

    ..., enzymes, antingens and radioactively labelled materials, and detailed treatments of micro disc electrophoresis, preparative polyacrylamide gel electrophoresis and many other techniques for special problems...

  14. CT reconstruction technique in lumbar intraneuroforaminal disc herniation

    International Nuclear Information System (INIS)

    Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

    1988-01-01

    The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach. (orig.)

  15. CT reconstruction technique in lumbar intraneuroforaminal disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

    1988-04-01

    The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach.

  16. Vascular complications of prosthetic inter-vertebral discs.

    Science.gov (United States)

    Daly, Kevin J; Ross, E Raymond S; Norris, Heather; McCollum, Charles N

    2006-10-01

    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had eroded into the bifurcation of the inferior vena cava and the left common iliac vein. In three cases the aortic bifurcation was also involved. The fibrosis was so severe that dissecting out the arteries and veins to provide access to the relevant disc proved impossible. Formal division of the left common iliac vein and artery with subsequent repair was our solution. Anterior inter-vertebral disc displacement was associated with severe vascular injury. Preventing anterior disc displacement is essential in disc design. In the event of anterior displacement, disc removal should be planned with a Vascular Surgeon.

  17. Metallicity gradient of the thick disc progenitor at high redshift

    Science.gov (United States)

    Kawata, Daisuke; Allende Prieto, Carlos; Brook, Chris B.; Casagrande, Luca; Ciucă, Ioana; Gibson, Brad K.; Grand, Robert J. J.; Hayden, Michael R.; Hunt, Jason A. S.

    2018-01-01

    We have developed a novel Markov Chain Monte Carlo chemical 'painting' technique to explore possible radial and vertical metallicity gradients for the thick disc progenitor. In our analysis, we match an N-body simulation to the data from the Apache Point Observatory Galactic Evolution Experiment survey. We assume that the thick disc has a constant scaleheight and has completed its formation at an early epoch, after which time radial mixing of its stars has taken place. Under these assumptions, we find that the initial radial metallicity gradient of the thick disc progenitor should not be negative, but either flat or even positive, to explain the current negative vertical metallicity gradient of the thick disc. Our study suggests that the thick disc was built-up in an inside-out and upside-down fashion, and older, smaller and thicker populations are more metal poor. In this case, star-forming discs at different epochs of the thick disc formation are allowed to have different radial metallicity gradients, including a negative one, which helps to explain a variety of slopes observed in high-redshift disc galaxies. This scenario helps to explain the positive slope of the metallicity-rotation velocity relation observed for the Galactic thick disc. On the other hand, radial mixing flattens the slope of an existing gradient.

  18. Apparent quasar disc sizes in the "bird's nest" paradigm

    Science.gov (United States)

    Abolmasov, P.

    2017-04-01

    Context. Quasar microlensing effects make it possible to measure the accretion disc sizes around distant supermassive black holes that are still well beyond the spatial resolution of contemporary instrumentation. The sizes measured with this technique appear inconsistent with the standard accretion disc model. Not only are the measured accretion disc sizes larger, but their dependence on wavelength is in most cases completely different from the predictions of the standard model. Aims: We suggest that these discrepancies may arise not from non-standard accretion disc structure or systematic errors, as it was proposed before, but rather from scattering and reprocession of the radiation of the disc. In particular, the matter falling from the gaseous torus and presumably feeding the accretion disc may at certain distances become ionized and produce an extended halo that is free from colour gradients. Methods: A simple analytical model is proposed assuming that a geometrically thick translucent inflow acts as a scattering mirror changing the apparent spatial properties of the disc. This inflow may be also identified with the broad line region or its inner parts. Results: Such a model is able to explain the basic properties of the apparent disc sizes, primarily their large values and their shallow dependence on wavelength. The only condition required is to scatter a significant portion of the luminosity of the disc. This can easily be fulfilled if the scattering inflow has a large geometrical thickness and clumpy structure.

  19. Notochord Cells in Intervertebral Disc Development and Degeneration

    Science.gov (United States)

    McCann, Matthew R.; Séguin, Cheryle A.

    2016-01-01

    The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches. PMID:27252900

  20. Notochord Cells in Intervertebral Disc Development and Degeneration

    Directory of Open Access Journals (Sweden)

    Matthew R. McCann

    2016-01-01

    Full Text Available The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches.

  1. Mechanical design criteria for intervertebral disc tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2010-04-19

    Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviors, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive, and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying where functional equivalence was achieved, and where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. Copyright 2009 Elsevier Ltd. All rights reserved.

  2. Developments in intervertebral disc disease research: pathophysiology, mechanobiology, and therapeutics.

    Science.gov (United States)

    Weber, Kathryn T; Jacobsen, Timothy D; Maidhof, Robert; Virojanapa, Justin; Overby, Chris; Bloom, Ona; Quraishi, Shaheda; Levine, Mitchell; Chahine, Nadeen O

    2015-03-01

    Low back pain is a leading cause of disability worldwide and the second most common cause of physician visits. There are many causes of back pain, and among them, disc herniation and intervertebral disc degeneration are the most common diagnoses and targets for intervention. Currently, clinical treatment outcomes are not strongly correlated with diagnoses, emphasizing the importance for characterizing more completely the mechanisms of degeneration and their relationships with symptoms. This review covers recent studies elucidating cellular and molecular changes associated with disc mechanobiology, as it relates to degeneration and regeneration. Specifically, we review findings on the biochemical changes in disc diseases, including cytokines, chemokines, and proteases; advancements in disc disease diagnostics using imaging modalities; updates on studies examining the response of the intervertebral disc to injury; and recent developments in repair strategies, including cell-based repair, biomaterials, and tissue engineering. Findings on the effects of the omega-6 fatty acid, linoleic acid, on nucleus pulposus tissue engineering are presented. Studies described in this review provide greater insights into the pathogenesis of disc degeneration and may define new paradigms for early or differential diagnostics of degeneration using new techniques such as systemic biomarkers. In addition, research on the mechanobiology of disease enriches the development of therapeutics for disc repair, with potential to diminish pain and disability associated with disc degeneration.

  3. Acupuncture and Spontaneous Regression of a Radiculopathic Cervical Herniated Disc

    Directory of Open Access Journals (Sweden)

    Kim Sung-Ha

    2012-06-01

    Full Text Available The spontaneous regression of herniated cervical discs is not a well-established phenomenon. However, we encountered a case of a spontaneous regression of a severe radiculopathic herniated cervical disc that was treated with acupuncture, pharmacopuncture, and herb medicine. The symptoms were improved within 12 months of treatment. Magnetic resonance imaging (MRI conducted at that time revealed marked regression of the herniated disc. This case provides an additional example of spontaneous regression of a herniated cervical disc documented by MRI following non-surgical treatment.

  4. Beyond the standard model of the disc-line spectral profiles from black hole accretion discs

    Czech Academy of Sciences Publication Activity Database

    Sochora, Vjačeslav; Karas, Vladimír; Svoboda, Jiří; Dovčiak, Michal

    2014-01-01

    Roč. 54, č. 4 (2014), s. 301-304 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GC13-00070J Institutional support: RVO:67985815 Keywords : accretion discs * black hole physics * galactic nuclei Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  5. Inner disc obscuration in GRS 1915+105 based on relativistic slim disc model

    Czech Academy of Sciences Publication Activity Database

    Vierdayanti, K.; Sądowski, A.; Mineshige, L.S.; Bursa, Michal

    2013-01-01

    Roč. 436, č. 1 (2013), s. 71-81 ISSN 0035-8711 Institutional support: RVO:67985815 Keywords : accretion discs * black hole physics * GRS 1915+105 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.226, year: 2013

  6. Confirming chemical clocks: asteroseismic age dissection of the Milky Way disc(s)

    DEFF Research Database (Denmark)

    Silva Aguirre, V.; Bojsen-Hansen, M.; Slumstrup, D.

    2018-01-01

    Investigations of the origin and evolution of the Milky Way disc have long relied on chemical and kinematic identifications of its components to reconstruct our Galactic past. Difficulties in determining precise stellar ages have restricted most studies to small samples, normally confined to the ...

  7. Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load

    International Nuclear Information System (INIS)

    Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.

    1988-01-01

    Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of 3 H 2 O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the 3 H 2 O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc

  8. Math anxiety and exposure to statistics in messages about genetically modified foods: effects of numeracy, math self-efficacy, and form of presentation.

    Science.gov (United States)

    Silk, Kami J; Parrott, Roxanne L

    2014-01-01

    Health risks are often communicated to the lay public in statistical formats even though low math skills, or innumeracy, have been found to be prevalent among lay individuals. Although numeracy has been a topic of much research investigation, the role of math self-efficacy and math anxiety on health and risk communication processing has received scant attention from health communication researchers. To advance theoretical and applied understanding regarding health message processing, the authors consider the role of math anxiety, including the effects of math self-efficacy, numeracy, and form of presenting statistics on math anxiety, and the potential effects for comprehension, yielding, and behavioral intentions. The authors also examine math anxiety in a health risk context through an evaluation of the effects of exposure to a message about genetically modified foods on levels of math anxiety. Participants (N = 323) were randomly assigned to read a message that varied the presentation of statistical evidence about potential risks associated with genetically modified foods. Findings reveal that exposure increased levels of math anxiety, with increases in math anxiety limiting yielding. Moreover, math anxiety impaired comprehension but was mediated by perceivers' math confidence and skills. Last, math anxiety facilitated behavioral intentions. Participants who received a text-based message with percentages were more likely to yield than participants who received either a bar graph with percentages or a combined form. Implications are discussed as they relate to math competence and its role in processing health and risk messages.

  9. A computational study of intervertebral disc degeneration in relation to changes in regional tissue composition and disc nutrition

    OpenAIRE

    Ruiz Wills, Carlos

    2015-01-01

    Up to 85% of the world population suffers from low back pain, a clinical condition often related to the intervertebral disc (IVD) degeneration (DD). Altered disc cell nutrition affects cell viability and can generate catabolic cascades that degrade the extracellular matrix (ECM). Also, a major degenerative biochemical change in the disc is the proteoglycan (PG) loss, which affects the osmotic pressure and hydration that is critical for cell nutrition. However, the relationship between biochem...

  10. Secular instabilities of Keplerian stellar discs

    Science.gov (United States)

    Kaur, Karamveer; Kazandjian, Mher V.; Sridhar, S.; Touma, Jihad R.

    2018-05-01

    We present idealized models of a razor-thin, axisymmetric, Keplerian stellar disc around a massive black hole, and study non-axisymmetric secular instabilities in the absence of either counter-rotation or loss cones. These discs are prograde mono-energetic waterbags, whose phase-space distribution functions are constant for orbits within a range of eccentricities (e) and zero outside this range. The linear normal modes of waterbags are composed of sinusoidal disturbances of the edges of distribution function in phase space. Waterbags that include circular orbits (polarcaps) have one stable linear normal mode for each azimuthal wavenumber m. The m = 1 mode always has positive pattern speed and, for polarcaps consisting of orbits with e normal modes for each m, which can be stable or unstable. We derive analytical expressions for the instability condition, pattern speeds, growth rates, and normal mode structure. Narrow bands are unstable to modes with a wide range in m. Numerical simulations confirm linear theory and follow the non-linear evolution of instabilities. Long-time integration suggests that instabilities of different m grow, interact non-linearly, and relax collisionlessly to a coarse-grained equilibrium with a wide range of eccentricities.

  11. The cellular memory disc of reprogrammed cells.

    Science.gov (United States)

    Anjamrooz, Seyed Hadi

    2013-04-01

    The crucial facts underlying the low efficiency of cellular reprogramming are poorly understood. Cellular reprogramming occurs in nuclear transfer, induced pluripotent stem cell (iPSC) formation, cell fusion, and lineage-switching experiments. Despite these advances, there are three fundamental problems to be addressed: (1) the majority of cells cannot be reprogrammed, (2) the efficiency of reprogramming cells is usually low, and (3) the reprogrammed cells developed from a patient's own cells activate immune responses. These shortcomings present major obstacles for using reprogramming approaches in customised cell therapy. In this Perspective, the author synthesises past and present observations in the field of cellular reprogramming to propose a theoretical picture of the cellular memory disc. The current hypothesis is that all cells undergo an endogenous and exogenous holographic memorisation such that parts of the cellular memory dramatically decrease the efficiency of reprogramming cells, act like a barrier against reprogramming in the majority of cells, and activate immune responses. Accordingly, the focus of this review is mainly to describe the cellular memory disc (CMD). Based on the present theory, cellular memory includes three parts: a reprogramming-resistance memory (RRM), a switch-promoting memory (SPM) and a culture-induced memory (CIM). The cellular memory arises genetically, epigenetically and non-genetically and affects cellular behaviours. [corrected].

  12. Auto fluorescence of intervertebral disc tissue: a new diagnostic tool.

    Science.gov (United States)

    Hoell, T; Huschak, G; Beier, A; Hüttmann, G; Minkus, Y; Holzhausen, H J; Meisel, H J

    2006-08-01

    The paper reports on auto fluorescence phenomena of inter-vertebral human discs. It systematically investigates the auto fluorescence effects of ex vivo disc specimen and reports on surgical cases to demonstrate the potential value of the new method. The paper offers biologic explanations of the phenomenon and discusses the potential value of the UV auto fluorescence technique as a diagnostic tool. Intra- and postoperative observations are made by a surgical microscope with an integrated UV light source. Quantitative measurements were carried out using a photon counter and a spectrometer ex vivo. The auto fluorescence phenomenon allows the differentiation of traumatized and degenerated disc tissue intraoperatively in some cases, it allows the differentiation of bony and collagen endplate in cervical disc surgery. The source of the auto fluorescent light emission are amino acids of the collagen molecules. The proteoglycan components and the liquid components of the disc do not show relevant auto fluorescence. Emission wavelength of disc material is equivalent to color perception. It differs due to different collagen composition of the intervertebral disc components from yellow-green to blue-green and can be visualized in situ by naked eye.UV-auto fluorescence of inter-vertebral discs is a new clinical tool that has the potential to differentiate disc material from the anatomical surrounding, to distinguish between different fractions of the disc and to give information on the quality and status of the disc material. Since the technology has just emerged, it needs further investigations to quantify the clinical observations reported in this paper.

  13. Disc-halo interactions in ΛCDM

    Science.gov (United States)

    Bauer, Jacob S.; Widrow, Lawrence M.; Erkal, Denis

    2018-05-01

    We present a new method for embedding a stellar disc in a cosmological dark matter halo and provide a worked example from a Λ cold dark matter zoom-in simulation. The disc is inserted into the halo at a redshift z = 3 as a zero-mass rigid body. Its mass and size are then increased adiabatically while its position, velocity, and orientation are determined from rigid-body dynamics. At z = 1, the rigid disc (RD) is replaced by an N-body disc whose particles sample a three-integral distribution function (DF). The simulation then proceeds to z = 0 with live disc (LD) and halo particles. By comparison, other methods assume one or more of the following: the centre of the RD during the growth phase is pinned to the minimum of the halo potential, the orientation of the RD is fixed, or the live N-body disc is constructed from a two rather than three-integral DF. In general, the presence of a disc makes the halo rounder, more centrally concentrated, and smoother, especially in the innermost regions. We find that methods in which the disc is pinned to the minimum of the halo potential tend to overestimate the amount of adiabatic contraction. Additionally, the effect of the disc on the subhalo distribution appears to be rather insensitive to the disc insertion method. The LD in our simulation develops a bar that is consistent with the bars seen in late-type spiral galaxies. In addition, particles from the disc are launched or `kicked up' to high galactic latitudes.

  14. Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

    Science.gov (United States)

    Chiang, Jaclyn; Yapp, Michael; Ly, Angelica; Hennessy, Michael P; Kalloniatis, Michael; Zangerl, Barbara

    2018-03-01

    This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

  15. News from the Library: Zentralblatt MATH: it's not all about maths

    CERN Multimedia

    CERN Library

    2011-01-01

    The CERN Library provides access to numerous and diverse information services of interest to the CERN community. Among them, Zentralblatt MATH stands out from our offer of online databases.   Zentralblatt MATH covers more than 3 million articles published in about 3500 journals, from 1826 to the present. Most bibliographic records are linked to the online published article. It covers all areas of pure and applied mathematics and also theoretical computer science, mathematical quantum and statistical physics, classical, solid and fluid mechanics, and general relativity and astronomy. Therefore, this database is useful in many disciplines beyond mathematics. It is daily updated and allows advanced search functionalities. Among others things, it includes the content of the Electronic Research Archive for Mathematics, the European Mathematical Information Service, and the Mathematics Preprint Search System. Please note the "Online Ordering" button next to every bibliographic recor...

  16. Math anxiety in second and third graders and its relation to mathematics achievement

    Directory of Open Access Journals (Sweden)

    Sarah eWu

    2012-06-01

    Full Text Available Although the detrimental effects of math anxiety in adults are well understood, few studies have examined how it affects younger children who are beginning to learn math in a formal academic setting. Here, we examine the relationship between math anxiety and math achievement in 2nd and 3rd graders. In response to the need for a grade-appropriate measure of assessing math anxiety in this group we first describe the development of Scale for Early Mathematics Anxiety (SEMA, a new measure for assessing math anxiety in 2nd and 3rd graders that is based on the Math Anxiety Rating Scale. We demonstrate the construct validity and reliability of the SEMA and use it to characterize the effect of math anxiety on standardized measures of math abilities, as assessed using the Wechsler Individual Achievement Test (WIAT-II. Math achievement, as measured by the WIAT-II Math Composite score, was significantly and negatively correlated with SEMA but not with trait anxiety scores. Additional analyses showed that SEMA scores were significantly correlated with scores on the Math Reasoning subtest, which involves more complex verbal problem solving, but not with the Numerical Operations subtest which assesses basic computation skills. Our results suggest that math anxiety has a pronounced effect on more demanding calculations. Our results further suggest that math anxiety has an equally detrimental impact on math achievement regardless of whether children have an anxiety related to numbers or to the situational and social experience of doing math. Critically, these effects were unrelated to trait anxiety, providing the first evidence that the specific effects of math anxiety can be detected in the earliest stages of formal math learning in school. Our findings provide new insights into the developmental origins of math anxiety, and further underscore the need to remediate math anxiety and its deleterious effects on math achievement in young children.

  17. Tutoring math platform accessible for visually impaired people.

    Science.gov (United States)

    Maćkowski, Michał Sebastian; Brzoza, Piotr Franciszek; Spinczyk, Dominik Roland

    2018-04-01

    There are many problems with teaching and assessing impaired students in higher education, especially in technical science, where the knowledge is represented mostly by structural information like: math formulae, charts, graphs, etc. Developing e-learning platform for distance education solves this problem only partially due to the lack of accessibility for the blind. The proposed method is based on the decomposition of the typical mathematical exercise into a sequence of elementary sub-exercises. This allows for interactive resolving of math exercises and assessment of the correctness of exercise solutions at every stage. The presented methods were prepared and evaluated by visually impaired people and students. The article presents the accessible interactive tutoring platform for math teaching and assessment, and experience in exploring it. The results of conducted research confirm good understanding of math formulae described according to elaborated rules. Regardless of the level of complexity of the math formulae the level of math formulae understanding is higher for alternative structural description. The proposed solution enables alternative descriptions of math formulae. Based on the research results, the tool for computer-aided interactive learning of mathematics adapted to the needs of the blind has been designed, implemented and deployed as a platform for on-site and online and distance learning. The designed solution can be very helpful in overcoming many barriers that occur while teaching impaired students. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Insecure attachment is associated with math anxiety in middle childhood.

    Science.gov (United States)

    Bosmans, Guy; De Smedt, Bert

    2015-01-01

    Children's anxiety for situations requiring mathematical problem solving, a concept referred to as math anxiety, has a unique and detrimental impact on concurrent and long-term mathematics achievement and life success. Little is known about the factors that contribute to the emergence of math anxiety. The current study builds on the hypothesis that math anxiety might reflect a maladaptive affect regulation mechanism that is characteristic for insecure attachment relationships. To test this hypothesis, 87 children primary school children (M age = 10.34 years; SD age = 0.63) filled out questionnaires measuring insecure attachment and math anxiety. They all completed a timed and untimed standardized test of mathematics achievement. Our data revealed that individual differences in math anxiety were significantly related to insecure attachment, independent of age, sex, and IQ. Both tests of mathematics achievement were associated with insecure attachment and this effect was mediated by math anxiety. This study is the first to indicate that math anxiety might develop in the context of insecure parent-child attachment relationships.

  19. Insecure attachment is associated with math anxiety in middle childhood

    Directory of Open Access Journals (Sweden)

    Guy eBosmans

    2015-10-01

    Full Text Available Children’s anxiety for situations requiring mathematical problem solving, a concept referred to as math anxiety, has a unique and detrimental impact on concurrent and long-term mathematics achievement and life success. Little is known about the factors that contribute to the emergence of math anxiety. The current study builds on the hypothesis that math anxiety might reflect a maladaptive affect-regulation mechanism that is characteristic for insecure attachment relationships. To test this hypothesis, 87 children primary school children (Mage = 10.34 years; SDage = 0.63 filled out questionnaires measuring insecure attachment and math anxiety. They all completed a timed and untimed standardized test of mathematics achievement. Our data revealed that individual differences in math anxiety were significantly related to insecure attachment, independent of age, sex and IQ. Both tests of mathematics achievement were associated with insecure attachment and this effect was mediated by math anxiety. This study is the first to indicate that math anxiety might develop in the context of insecure parent-child attachment relationships.

  20. Using the Intel Math Kernel Library on Peregrine | High-Performance

    Science.gov (United States)

    Computing | NREL the Intel Math Kernel Library on Peregrine Using the Intel Math Kernel Library on Peregrine Learn how to use the Intel Math Kernel Library (MKL) with Peregrine system software. MKL architectures. Core math functions in MKL include BLAS, LAPACK, ScaLAPACK, sparse solvers, fast Fourier