18,488 research outputs found

    An Economic Theory of Academic Engagement Norms: The Struggle for Popularity and Normative Hegemony in Secondary Schools

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    [Excerpt] Why and how do groups create norms? Kenneth Arrow proposed that “norms of social behavior, including ethical and moral codes, 
.are reactions of society to compensate for market failure”. This internalize the real externalities explanation for norms is also standard among rational choice theorists in sociology. The situation becomes more complex when we recognize some actions create positive externalities for some individuals and negative externalities for others. Often this results in no norm being established. However, sometimes one segment of a social system has normative hegemony and enforces norms that enhance their power and prestige at the expense of other groups. Norms regarding caste in India, for example, were functional for Brahmins but humiliating for Harijans. Caste and status norms of this type will also be referred to as “Honor us; Not them” norms. Such norms arise when one group is much more powerful (has greater ability to enforce their preferred social norm) than other groups and it imposes its will on others. An additional requirement is that the people who oppose the norm established by the dominant group must be unable or unwilling to leave the social system in which the norm operates

    Peer Harassment: A Weapon in the Struggle for Popularity and Normative Hegemony in American Secondary Schools

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    This paper addresses two of secondary education’s most serious problems—peer abuse of weaker socially unskilled students and a peer culture that in most schools discourages many students from trying to be all that they can be academically. We have documented the two problems by reviewing ethnographies of secondary schools, by interviewing students in eight suburban high schools and by analyzing data from questionnaires completed by nearly 100,000 students at Educational Excellence Alliance schools. Grounded in these observations, we built a simple mathematical model of peer harassment and popularity and of the pressures for conformity that are created by the struggle for popularity and then tested it in data from the Educational Excellence Alliance. Students entering middle school learn its norms by trying to copy the traits and behaviors of students who are respected and by avoiding contact with those who are frequently harassed. Peer norms are enforced by encouraging ‘wannabes,’ aspirants for admission to popular crowds, to harass those who visibly violate them. Consequently, one can infer the norms by noting who gets harassed and who doesn’t. Traits that in EEA data led to higher risks of being bullied and harassed were: being in a special education, being in gifted programs, taking accelerated courses in middle school, tutoring other students, enjoying school assignments, taking a theatre course, not liking rap-hip hop music and liking instead musicals, heavy metal, country, or classical music. The relationship between harassment and academic effort was curvilinear; both the nerds and the slackers were harassed. To some degree these norms are, as Kenneth Arrow suggests, trying to internalize externalities. But why are music preferences such good predictors of harassment? Why are the student tutors victimized? We propose that norms also have a “We’re cool, Honor us” function of legitimating the high status that the leading crowds claim for themselves. As a result the traits and interests that members of leading crowds have in common tend to become normative for everyone. The norms that prevailed were: “Spend your time socializing, do not “study too hard.” Value classmates for their athletic prowess and their attractiveness, not their interest in history or their accomplishments in science.

    Hover performance tests of baseline metal and Advanced Technology Blade (ATB) rotor systems for the XV-15 tilt rotor aircraft

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    Rotor hover performance data were obtained for two full-scale rotor systems designed for the XV-15 Tilt Rotor Research Aircraft. One rotor employed the rectangular planform metal blades (rotor solidity = 0.089) which were used on the initial flight configuration of the XV-15. The second rotor configuration examined the nonlinear taper, composite-construction, Advanced Technology Blade (ATB), (rotor solidity = 0.10) designed to replace the metal blades on the XV-15. Variations of the baseline ATB tip and cuff shapes were also tested. A new six-component rotor force and moment balance designed to obtain highly accurate data over a broad range of thrust and torque conditions is described. The test data are presented in nondimensional coefficient form for the performance results, and in dimensional form for the steady and alternating loads. Some wake and acoustic data are also shown

    Resonances, Unstable Systems and Irreversibility: Matter Meets Mind

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    The fundamental time-reversal invariance of dynamical systems can be broken in various ways. One way is based on the presence of resonances and their interactions giving rise to unstable dynamical systems, leading to well-defined time arrows. Associated with these time arrows are semigroups bearing time orientations. Usually, when time symmetry is broken, two time-oriented semigroups result, one directed toward the future and one directed toward the past. If time-reversed states and evolutions are excluded due to resonances, then the status of these states and their associated backwards-in-time oriented semigroups is open to question. One possible role for these latter states and semigroups is as an abstract representation of mental systems as opposed to material systems. The beginnings of this interpretation will be sketched.Comment: 9 pages. Presented at the CFIF Workshop on TimeAsymmetric Quantum Theory: The Theory of Resonances, 23-26 July 2003, Instituto Superior Tecnico, Lisbon, Portugal; and at the Quantum Structures Association Meeting, 7-22 July 2004, University of Denver. Accepted for publication in the Internation Journal of Theoretical Physic

    Spectral signatures of the Luttinger liquid to charge-density-wave transition

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    Electron- and phonon spectral functions of the one-dimensional, spinless-fermion Holstein model at half filling are calculated in the four distinct regimes of the phase diagram, corresponding to an attractive or repulsive Luttinger liquid at weak electron-phonon coupling, and a band- or polaronic insulator at strong coupling. The results obtained by means of kernel polynomial and systematic cluster approaches reveal substantially different physics in these regimes and further indicate that the size of the phonon frequency significantly affects the nature of the quantum Peierls phase transition.Comment: 5 pages, 4 figures; final version, accepted for publication in Physical Review

    Phase Transitions in the Spin-Half J_1--J_2 Model

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    The coupled cluster method (CCM) is a well-known method of quantum many-body theory, and here we present an application of the CCM to the spin-half J_1--J_2 quantum spin model with nearest- and next-nearest-neighbour interactions on the linear chain and the square lattice. We present new results for ground-state expectation values of such quantities as the energy and the sublattice magnetisation. The presence of critical points in the solution of the CCM equations, which are associated with phase transitions in the real system, is investigated. Completely distinct from the investigation of the critical points, we also make a link between the expansion coefficients of the ground-state wave function in terms of an Ising basis and the CCM ket-state correlation coefficients. We are thus able to present evidence of the breakdown, at a given value of J_2/J_1, of the Marshall-Peierls sign rule which is known to be satisfied at the pure Heisenberg point (J_2 = 0) on any bipartite lattice. For the square lattice, our best estimates of the points at which the sign rule breaks down and at which the phase transition from the antiferromagnetic phase to the frustrated phase occurs are, respectively, given (to two decimal places) by J_2/J_1 = 0.26 and J_2/J_1 = 0.61.Comment: 28 pages, Latex, 2 postscript figure

    Noisy regression and classification with continuous multilayer networks

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    We investigate zero temperature Gibbs learning for two classes of unrealizable rules which play an important role in practical applications of multilayer neural networks with differentiable activation functions: classification problems and noisy regression problems. Considering one step of replica symmetry breaking, we surprisingly find that for sufficiently large training sets the stable state is replica symmetric even though the target rule is unrealizable. Further, the classification problem is shown to be formally equivalent to the noisy regression problem.Comment: 7 pages, including 2 figure

    Literature Survey of Radiochemical Cross-section Data Below 425 Mev

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    Literature survey of radiochemical cross sections below 425 Me

    Assessment and diagnosis of Developmental Language Disorder: The experiences of speech and language therapists

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    © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (http://www.creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).Background: For many years research and practice have noted the impact of the heterogeneous nature of Developmental Language Disorder (also known as language impairment or specific language impairment) on diagnosis and assessment. Recent research suggests the disorder is not restricted to the language domain and against this background, the challenge for the practitioner is to provide accurate assessment and effective therapy. The language practitioner aims to support the child and their carers to achieve the best outcomes. However, little is known about the experiences of the language practitioner in the assessment process, in contrast to other childhood disorders, yet their expertise is central in the assessment and diagnosis of children with language disorder. Aims: This study aimed to provide a detailed qualitative description of the experiences of speech and language therapists involved in the assessment and diagnosis of children with Developmental Language Disorder. Methods & Procedures: The qualitative study included three focus groups to provide a credible and rich description of the experiences of speech and language therapists involved in the assessment of Developmental Language Disorder. The speech and language therapists who participated in the study were recruited from three NHS Trusts across the UK and all were directly involved in the assessment and diagnosis procedures. The lengths of practitioner experience ranged from 2 years to 38 years. The data was analysed using a thematic analysis in accordance with the principles set out by Braun & Clarke (2006). Outcomes & Results: The data showed a number of key themes concerning the experiences of speech and language therapists in assessing children with Developmental Language Disorder (DLD). These themes ranged from the participants’ experiences of the barriers to early referral, challenges for assessment and the concerns over continued future support. Conclusions & Implications: This study provides first-hand evidence from speech and language therapists in the assessment of children with Developmental Language Disorder, drawing together experiences from language practitioners from different regions. The findings provide insight to the barriers to referral, the potential variations in the assessment process, the role of practitioner expertise and the challenges faced them. The importance of early intervention, useful assessment tools and future support were expressed. Taken together, the results relate to some issues to be addressed on a practical level and a continuing need for initiatives to raise awareness of DLD in the public domain.Peer reviewe

    High-Order Coupled Cluster Method (CCM) Calculations for Quantum Magnets with Valence-Bond Ground States

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    In this article, we prove that exact representations of dimer and plaquette valence-bond ket ground states for quantum Heisenberg antiferromagnets may be formed via the usual coupled cluster method (CCM) from independent-spin product (e.g. N\'eel) model states. We show that we are able to provide good results for both the ground-state energy and the sublattice magnetization for dimer and plaquette valence-bond phases within the CCM. As a first example, we investigate the spin-half J1J_1--J2J_2 model for the linear chain, and we show that we are able to reproduce exactly the dimerized ground (ket) state at J2/J1=0.5J_2/J_1=0.5. The dimerized phase is stable over a range of values for J2/J1J_2/J_1 around 0.5. We present evidence of symmetry breaking by considering the ket- and bra-state correlation coefficients as a function of J2/J1J_2/J_1. We then consider the Shastry-Sutherland model and demonstrate that the CCM can span the correct ground states in both the N\'eel and the dimerized phases. Finally, we consider a spin-half system with nearest-neighbor bonds for an underlying lattice corresponding to the magnetic material CaV4_4O9_9 (CAVO). We show that we are able to provide excellent results for the ground-state energy in each of the plaquette-ordered, N\'eel-ordered, and dimerized regimes of this model. The exact plaquette and dimer ground states are reproduced by the CCM ket state in their relevant limits.Comment: 34 pages, 13 figures, 2 table
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