3,176 research outputs found

    Dr. Marie Zakrzewska.

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    Contrasting Properties of Motor Output from the Supplementary Motor Area and Primary Motor Cortex in Rhesus Macaques

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    The goal of this study was to assess the motor output capabilities of the forelimb representation of the supplementary motor area (SMA) in terms of the sign, latency and strength of effects on electromyographic (EMG) activity. Stimulus triggered averages of EMG activity from 24 muscles of the forelimb were computed in SMA during a reach-to-grasp task. Poststimulus facilitation (PStF) from SMA had two distinct peaks (15.2 and 55.2 ms) and one poststimulus suppression (PStS) peak (32.4 ms). The short onset latency PStF and PStS of SMA were 5.5 and 16.8 ms longer than those of the primary motor cortex (M1). The average magnitudes (peak increase or decrease above baseline) of the short and long latency PStF and PStS from SMA at 60 μA were 13.8, 11.3 and −11.9% respectively. In comparison, M1 PStF and PStS magnitudes at 15 μA were 50.2 and −23.8%. Extrapolating M1 PStF magnitude to 60 μA yields a mean effect that is nearly 15 times greater than the mean PStF from SMA. Moreover, unlike M1, the facilitation of distal muscles from SMA was not significantly greater than the facilitation of proximal muscles. We conclude that the output from SMA to motoneurons is markedly weaker compared with M1 raising doubts about the role of SMA corticospinal neurons in the direct control of muscle activit

    A dependent nominal type theory

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    Nominal abstract syntax is an approach to representing names and binding pioneered by Gabbay and Pitts. So far nominal techniques have mostly been studied using classical logic or model theory, not type theory. Nominal extensions to simple, dependent and ML-like polymorphic languages have been studied, but decidability and normalization results have only been established for simple nominal type theories. We present a LF-style dependent type theory extended with name-abstraction types, prove soundness and decidability of beta-eta-equivalence checking, discuss adequacy and canonical forms via an example, and discuss extensions such as dependently-typed recursion and induction principles

    Negative thermal expansion of MgB2_{2} in the superconducting state and anomalous behavior of the bulk Gr\"uneisen function

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    The thermal expansion coefficient α\alpha of MgB2_2 is revealed to change from positive to negative on cooling through the superconducting transition temperature TcT_c. The Gr\"uneisen function also becomes negative at TcT_c followed by a dramatic increase to large positive values at low temperature. The results suggest anomalous coupling between superconducting electrons and low-energy phonons.Comment: 5 figures. submitted to Phys. Rev. Let

    Summation of Power Series by Self-Similar Factor Approximants

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    A novel method of summation for power series is developed. The method is based on the self-similar approximation theory. The trick employed is in transforming, first, a series expansion into a product expansion and in applying the self-similar renormalization to the latter rather to the former. This results in self-similar factor approximants extrapolating the sought functions from the region of asymptotically small variables to their whole domains. The method of constructing crossover formulas, interpolating between small and large values of variables is also analysed. The techniques are illustrated on different series which are typical of problems in statistical mechanics, condensed-matter physics, and, generally, in many-body theory.Comment: 30 pages + 5 ps figures, some misprints have been correcte

    Sustainable Affordable Housing - Submission to Inquiry into First Home Ownership

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    The Institute welcomes this opportunity to submit comments to the Commissions Inquiry evaluating the affordability and availability of housing for first home buyers. The Institute for Sustainable Futures is a self-funded research and consulting institute of the University of Technology, Sydney. The Institutes mission is to support and create change towards sustainable futures by working with government, industry and the community. Social sustainability, sustainable housing and sustainable urban infrastructure for energy, water and transport are all key parts of this mission.1 This submission seeks to evaluate the affordability and availability of housing for first home buyers within the framework of ecologically sustainable development (ESD). It is in two parts. Part I: Submission provides the framework. Part II: Comments on the Commissions Issues Paper provides more details on this framework under the broad headings used in the Commissions Issues Paper

    Nominal Unification of Higher Order Expressions with Recursive Let

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    A sound and complete algorithm for nominal unification of higher-order expressions with a recursive let is described, and shown to run in non-deterministic polynomial time. We also explore specializations like nominal letrec-matching for plain expressions and for DAGs and determine the complexity of corresponding unification problems.Comment: Pre-proceedings paper presented at the 26th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2016), Edinburgh, Scotland UK, 6-8 September 2016 (arXiv:1608.02534

    How Coaching Changes Teaching Practices In Elementary Literacy Instruction

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    Professional development is a major initiative in many school districts in an effort to help teachers improve teaching and learning. Literacy coaches are becoming increasingly prevalent in many elementary school buildings. This study examined the effects literacy coaches have on teaching practices. More specifically, it examined to what degree literacy coaches affect teaching. Utilizing an electronic survey, 18 elementary classroom teachers participated in providing feedback relative to their enjoyment, new learning, changes in practice, and subsequent changes in student learning that occurred as a result of literacy coaching. Teachers indicated new learning was occurring despite how many years they had been teaching. Teachers who were newer to the profession, fewer than 10 years’ experience, indicated high levels of enjoyment and changes to their practice and noted positive changes in student learning. Teachers with more experience indicated lower levels of enjoyment, but some still reported they noticed a change in their teaching practices for the short term at least. This study has substantial implications for the value of literacy instructional coaches and identifies particular coaching moves that teachers identified as useful. This study supports the work being done in schools and the investment being made in literacy coaching. The argument for providing job-embedded professional development is strong in this study

    Dynamics of direct inter-pack encounters in endangered African wild dogs

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    Aggressive encounters may have important life history consequences due to the potential for injury and death, disease transmission, dispersal opportunities or exclusion from key areas of the home range. Despite this, little is known of their detailed dynamics, mainly due to the difficulties of directly observing encounters in detail. Here, we describe detailed spatial dynamics of inter-pack encounters in African wild dogs (Lycaon pictus), using data from custom-built high-resolution GPS collars in 11 free-ranging packs. On average, each pack encountered another pack approximately every 7 weeks and met each neighbour twice each year. Surprisingly, intruders were more likely to win encounters (winning 78.6% of encounters by remaining closer to the site in the short term). However, intruders did tend to move farther than residents toward their own range core in the short-term (1 h) post-encounter, and if this were used to indicate losing an encounter, then the majority (73.3%) of encounters were won by residents. Surprisingly, relative pack size had little effect on encounter outcome, and injuries were rare (<15% of encounters). These results highlight the difficulty of remotely scoring encounters involving mobile participants away from static defendable food resources. Although inter-pack range overlap was reduced following an encounter, encounter outcome did not seem to drive this, as both packs shifted their ranges post-encounter. Our results indicate that inter-pack encounters may be lower risk than previously suggested and do not appear to influence long-term movement and ranging
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