The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform

Mead, Lawrence R. - One of the best experts on this subject based on the ideXlab platform.

  • Can PT-Symmetric Quantum Mechanics be a Viable Alternative Quantum Theory?
    2014
    Co-Authors: Lee Sungwook, Mead, Lawrence R.
    Abstract:

    Update: A time-independent $n\times n$ PT-symmetric (and symmetric) Hamiltonian is diagonalizable since it has all distinct real eigenvalues and the resulting diagonal matrix is a real symmetric matrix. The diagonalization results an isometry so there shouldn't be any issue with unitarity and unfortunately this very elementary Mathematical Fact somehow did not draw the authors' attention. However, PT-symmetric quantum mechanics is not out of trouble. For time-dependent PT-symmetric (and symmetric) Hamiltonians (even $2\times 2$ ones) the authors observed that there is a violation of unitarity. Moreover, the first named author showed in his recent article arXiv:1312.7738 that PT-symmetric quantum mechanics is indeed a certain kind of Hermitian quantum mechanics and that in order for time-evolution to be unitary with respect to $J$-inner product (one that gives rise to a Hilbert space structure on the space of state functions), the potential energy operator $V(x)$ must be real. This means that those complex PT-symmetric Hamiltonians that have been studied by physicists are unfortunately unphysical. The first named author discussed in a subsequent article arXiv:1401.5149 that while finite-state PT-symmetric quantum mechanics with time-independent Hamiltonians is not physically any different from Hermitian quantum mechanics, PT-symmetric quantum mechanics exhibits a distinctive symmetry from that of Hermitian quantum mechanics.Comment: This paper has been withdrawn by the authors due to a crucial sign error in the proof of the authors' assertion about the unitarity issue with PT-symmetric quantum mechanic

Michael J Cook - One of the best experts on this subject based on the ideXlab platform.

  • adjunctive role for immediate feedback in the acquisition and retention of Mathematical Fact series by elementary school students classified with mild mental retardation
    Psychological Record, 2005
    Co-Authors: Roberta E Dihoff, Gary M Brosvic, Michael L Epstein, Michael J Cook
    Abstract:

    The effects of feedback on the acquisition and retention of Mathematical Fact series by elementary school students classified with mild mental retardation was examined in 4 studies. Immediate feedback was provided by either an educator or the Immediate Feedback Assessment Technique (IF AT), at the end of a test series by a review of correct solutions (delayed feedback), or for control purposes, with a Scantron form. Reductions in errors and inaccurate perseverative responding during intervention periods were higher, and the repetition of errors during maintenance test was lower, when feedback was provided by an educator in Study 1. These results were replicated and extended in Study 2 to the operation of subtraction. In Study 3, the concurrent presentation of both forms of immediate feedback was more effective than the presentation of either form separately. In Study 4, the adjunctive value of the IIF AT to facilitate the teaching-learning process was established, with higher levels of independent learning and retention demonstrated when the I F AT was available. The IF AT, as a simple paper and pencil tool, can assist the educator through the provision of individualized performance feedback and the encouraging of students to continue responding while simultaneously promoting independent learning.

Hsu Chien-en - One of the best experts on this subject based on the ideXlab platform.

  • [[alternative]]Mathematical Performance in Children with Developmental Language Disorder: A Study of Mandarin-Speaking Children
    國立台北護理健康大學語言治療與聽力研究所, 2020
    Co-Authors: Hsu Chien-en
    Abstract:

    [[abstract]]本研究旨在探討發展性語言障礙兒童（DLD）與典型發展同儕（TD）兒童在數學測驗中，百分位數、答題正確率、不同題型得分的表現差異。研究對象為144位四歲到小學三年級的DLD和TD兒童，共53位DLD兒童及91位TD兒童。每位兒童均施測標準化數學測驗「學童數學成就測驗」，比較兩組兒童在百分位數、答題正確率、及不同題型得分的差異。研究結果為（一）不論是學前或學齡DLD兒童，在百分位數及正確率的表現都顯著低於TD兒童。但是學齡的DLD兒童在百分位數及正確率都比學前DLD佳，反應年齡越大表現越佳的趨勢。（二）學前DLD兒童最明顯的困難是數數，所有學前DLD兒童在數數的得分都顯著低於TD同儕，數字認讀及數字書寫也的得分也顯著低於TD兒童。（三）學齡DLD兒童最明顯的困難是算術，小一小二DLD兒童的加減法得分顯著低於TD兒童，小三DLD兒童在加減法的得分並沒有顯著低於TD兒童，但在乘法和除法的得分顯著低於TD兒童。本研究發現無論在學前或是學齡DLD兒童除了，在數學的表現都顯著低於典型發展同儕，因此醫療人員及教師除了評估語障兒童的語言表現，也應參考其數學發展是否有落後的情形。[[abstract]]This study aims to investigate the Mathematical performance of Mandarin-speaking children with Developmental Language Disorder (DLD) and their chronological-age-matched peers. A total of 144 children, ranging from preschool to 3rd grade that met selection criteria participated in the study. Children were divided into DLD and Typically Developing (TD) groups. Standardized tests in language, cognition, and math are used to examine the performance and different error types in participants’ answers on standardized Mathematical test, with contents presented in different kinds of math task, including reciting, number sequence, counting, reading/writing numbers, magnitude comparison, arithmetic (including place value). Percentile, correctness, and scores were assessed to investigate the math performance between DLD and TD group.Children with DLD displayed poor performance in percentiles and correctness. In addition, deficit in counting and arithmetic were observed. DLD showed great difficulty in Mathematical Fact retrieval and have poor Mathematical knowledge. This study confirmed that both preschool and school-aged children with DLD have Mathematical performance and difficulties retrieving overlearned math Facts. Based on Dehaene’s Triple Code Model, children with DLD showed deficits in the two codes that involves auditory-verbal and visual-Arabic codes

Lee Sungwook - One of the best experts on this subject based on the ideXlab platform.

  • Can PT-Symmetric Quantum Mechanics be a Viable Alternative Quantum Theory?
    2014
    Co-Authors: Lee Sungwook, Mead, Lawrence R.
    Abstract:

    Update: A time-independent $n\times n$ PT-symmetric (and symmetric) Hamiltonian is diagonalizable since it has all distinct real eigenvalues and the resulting diagonal matrix is a real symmetric matrix. The diagonalization results an isometry so there shouldn't be any issue with unitarity and unfortunately this very elementary Mathematical Fact somehow did not draw the authors' attention. However, PT-symmetric quantum mechanics is not out of trouble. For time-dependent PT-symmetric (and symmetric) Hamiltonians (even $2\times 2$ ones) the authors observed that there is a violation of unitarity. Moreover, the first named author showed in his recent article arXiv:1312.7738 that PT-symmetric quantum mechanics is indeed a certain kind of Hermitian quantum mechanics and that in order for time-evolution to be unitary with respect to $J$-inner product (one that gives rise to a Hilbert space structure on the space of state functions), the potential energy operator $V(x)$ must be real. This means that those complex PT-symmetric Hamiltonians that have been studied by physicists are unfortunately unphysical. The first named author discussed in a subsequent article arXiv:1401.5149 that while finite-state PT-symmetric quantum mechanics with time-independent Hamiltonians is not physically any different from Hermitian quantum mechanics, PT-symmetric quantum mechanics exhibits a distinctive symmetry from that of Hermitian quantum mechanics.Comment: This paper has been withdrawn by the authors due to a crucial sign error in the proof of the authors' assertion about the unitarity issue with PT-symmetric quantum mechanic

Roberta E Dihoff - One of the best experts on this subject based on the ideXlab platform.

  • adjunctive role for immediate feedback in the acquisition and retention of Mathematical Fact series by elementary school students classified with mild mental retardation
    Psychological Record, 2005
    Co-Authors: Roberta E Dihoff, Gary M Brosvic, Michael L Epstein, Michael J Cook
    Abstract:

    The effects of feedback on the acquisition and retention of Mathematical Fact series by elementary school students classified with mild mental retardation was examined in 4 studies. Immediate feedback was provided by either an educator or the Immediate Feedback Assessment Technique (IF AT), at the end of a test series by a review of correct solutions (delayed feedback), or for control purposes, with a Scantron form. Reductions in errors and inaccurate perseverative responding during intervention periods were higher, and the repetition of errors during maintenance test was lower, when feedback was provided by an educator in Study 1. These results were replicated and extended in Study 2 to the operation of subtraction. In Study 3, the concurrent presentation of both forms of immediate feedback was more effective than the presentation of either form separately. In Study 4, the adjunctive value of the IIF AT to facilitate the teaching-learning process was established, with higher levels of independent learning and retention demonstrated when the I F AT was available. The IF AT, as a simple paper and pencil tool, can assist the educator through the provision of individualized performance feedback and the encouraging of students to continue responding while simultaneously promoting independent learning.