The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform

Lieselotte Sippel - One of the best experts on this subject based on the ideXlab platform.

  • Maximizing the benefits of peer Interaction: Form-focused instruction and peer feedback training
    Language Teaching Research, 2021
    Co-Authors: Lieselotte Sippel
    Abstract:

    This classroom study investigated the effectiveness of Form-focused instruction and peer feedback training to improve grammatical accuracy and thereby maximize learning opportunities during peer Interaction. Eighty-seven third-semester learners of German were assigned to a PI group (peer Interaction only), an FFI group (peer Interaction and Form-focused instruction), or a PFT group (peer Interaction, Form-focused instruction, and peer feedback training). During an instructional intervention over 3 class periods, participants in all 3 groups engaged in the same peer Interaction activities, but only the FFI group and the PFT group received Form-focused instruction on the grammatical target structure, the German present perfect tense. Critically, only the PFT group was trained to provide corrective feedback to peers. Results from a pretest and two posttests, all of which included an oral production task and an error correction task, showed that peer Interaction was effective when combined with Form-focused instruction, but more effective when peer feedback training was also provided to learners. These results underscore the importance of instruction on peer feedback for more successful peer Interaction activities.

  • maximizing the benefits of peer Interaction Form focused instruction and peer feedback training
    Language Teaching Research, 2021
    Co-Authors: Lieselotte Sippel
    Abstract:

    This classroom study investigated the effectiveness of Form-focused instruction and peer feedback training to improve grammatical accuracy and thereby maximize learning opportunities during peer in...

Joseph Abdou - One of the best experts on this subject based on the ideXlab platform.

  • The structure of unstable power mechanisms
    Economic Theory, 2012
    Co-Authors: Joseph Abdou
    Abstract:

    We study the structure of unstable power mechanisms. A power mechanism is modeled by an Interaction Form, the solution of which is called a settlement. By stability, we mean the existence of some settlement for any preference profile. Configurations that produce instability are called cycles. We introduce a stability index that measures the difficulty of emergence of cycles. Structural properties such as exactness, superadditivity, subadditivity and maximality provide indications about the type of instability that may affect the mechanism. We apply our analysis to strategic game Forms in the context of Nash-like solutions or core-like solutions. In particular, we establish an upper bound on the stability index of maximal Interaction Forms.

  • The Structure of Unstable Power Systems
    2009
    Co-Authors: Joseph Abdou
    Abstract:

    A power system is modeled by an Interaction Form, the solution of which is called a settlement. By stability we mean the existence of some settlement for any preference profile. Like in other models of power structure, instability is equivalent to the existence of a cycle. Structural properties of the system like maximality, regularity, superadditivity, subadditivity and exactness are defined and used to determine the type of instability that may affect the system. A Stability Index is introduced. Loosely speaking this index measures the difficulty of the emergence of configurations that produce a deadlock. As applications we have a characterization of solvable game Forms, an analysis of the structure of their instability and a localization of their stability index in case where solvability fails.

  • Stability Index of Interaction Forms
    Research Papers in Economics, 2008
    Co-Authors: Joseph Abdou
    Abstract:

    An Interaction Form is an abstract model of Interaction based on a description of power distribution among agents over alternatives. A solution known as the settlement set is defined at any preference profile. Necessary and sufficient conditions for stability, that is the existence of settlements, are established. A Stability Index that plays a role similar to that of the Naka- mura Number is defined. It measures, loosely speaking, the complexity of those configurations that prevent a settlement. To any strategic game Form one can associate an Interaction Form in such a way that given an equilibrium concept (e.g. Nash or strong Nash) and a preference profile, settlements of the Interaction Form are precisely the equilibrium outcomes of the resulting game. As a consequence we have necessary and sufficient conditions for the solvability of game Forms. The paper provides a localization of the index in case of unstability.

Jane Y Howe - One of the best experts on this subject based on the ideXlab platform.

  • tuning magnetoresistance and magnetic field dependent electroluminescence through mixing a strong spin orbital coupling molecule and a weak spin orbital coupling polymer
    Physical Review B, 2007
    Co-Authors: Jane Y Howe
    Abstract:

    We report a tunable magnetoresistance by uniFormly mixing strong-spin-orbital-coupling molecule fac-tris (2-phenylpyridinato) iridium [Ir(ppy)3] and weak-spin-orbital-coupling polymer poly(N-vinyl carbazole) (PVK). Three possible mechanisms, namely charge transport distribution, energy transfer, and intermolecular spin-orbital Interaction, are discussed to interpret the Ir(ppy)3 concentration-dependent magnetoresistance in the PVK+Ir(ppy)3 composite. The comparison between the magnetic field effects measured from energy-transfer and non-energy-transfer Ir(ppy)3 doped polymer composites indicates that energy transfer and intermolecular spin-orbital Interaction lead to rough and fine tuning for the magnetoresistance, respectively. Furthermore, the photocurrent dependence of magnetic field implies that the excited states contribute to the magnetoresistance through dissociation. As a result, the modification of singlet or triplet ratio of excited states through energy transfer and intermolecular spin-orbital Interaction Form a mechanism to tune the magnetoresistance in organic semiconducting materials.

Neri Merhav - One of the best experts on this subject based on the ideXlab platform.

  • Sequence Complexity and Work Extraction
    Journal of Statistical Mechanics: Theory and Experiment, 2015
    Co-Authors: Neri Merhav
    Abstract:

    We consider a simplified version of a solvable model by Mandal and Jarzynski, which constructively demonstrates the interplay between work extraction and the increase of the Shannon entropy of an inFormation reservoir which is in contact with a physical system. We extend Mandal and Jarzynski's main findings in several directions: First, we allow sequences of correlated bits rather than just independent bits. Secondly, at least for the case of binary inFormation, we show that, in fact, the Shannon entropy is only one measure of complexity of the inFormation that must increase in order for work to be extracted. The extracted work can also be upper bounded in terms of the increase in other quantities that measure complexity, like the predictability of future bits from past ones. Third, we point out to a partial extension to the case of non-binary inFormation (i.e., a larger alphabet), and finally, we extend the scope to the case where the incoming bits (before the Interaction) Form an individual sequence, rather than a random one. In this case, the entropy before the Interaction can be replaced by the Lempel-Ziv (LZ) complexity of the incoming sequence, a fact that gives rise to an entropic meaning of the LZ complexity, not only in inFormation theory, but also in physics.

  • Sequence complexity and work extraction
    arXiv: Statistical Mechanics, 2015
    Co-Authors: Neri Merhav
    Abstract:

    We consider a simplified version of a solvable model by Mandal and Jarzynski, which constructively demonstrates the interplay between work extraction and the increase of the Shannon entropy of an inFormation reservoir which is in contact with the physical system. We extend Mandal and Jarzynski's main findings in several directions: First, we allow sequences of correlated bits rather than just independent bits. Secondly, at least for the case of binary inFormation, we show that, in fact, the Shannon entropy is only one measure of complexity of the inFormation that must increase in order for work to be extracted. The extracted work can also be upper bounded in terms of the increase in other quantities that measure complexity, like the predictability of future bits from past ones. Third, we provide an extension to the case of non-binary inFormation (i.e., a larger alphabet), and finally, we extend the scope to the case where the incoming bits (before the Interaction) Form an individual sequence, rather than a random one. In this case, the entropy before the Interaction can be replaced by the Lempel-Ziv (LZ) complexity of the incoming sequence, a fact that gives rise to an entropic meaning of the LZ complexity, not only in inFormation theory, but also in physics.

Mariana F. Wolfner - One of the best experts on this subject based on the ideXlab platform.

  • evidence for structural constraint on ovulin a rapidly evolving drosophila melanogaster seminal protein
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Alex Wong, Shannon N Albright, Mariana F. Wolfner
    Abstract:

    The egg-laying hormone ovulin (Acp26Aa) is among the most rapidly evolving proteins in the Drosophila genome. Against the background of ovulin's high sequence variability within and between species, we have identified highly conserved motifs that may play an important structural role. Using yeast two-hybrid and GST-pull-down assays, we show that ovulin interacts with itself. The C terminus of ovulin is necessary and sufficient for self-Interaction, with its C-terminal 45 aa playing a major role. Under nonreducing conditions, ovulin participates in a high-molecular-mass complex, suggesting that it occurs in an oligomeric Form. One or more of three predicted coiled-coil domains in the C terminus of ovulin may be involved in its self-Interaction. These structural elements are conserved between species despite an overall rapid pace of evolution in ovulin's primary sequence. We therefore suggest that domains involved in ovulin's self-Interaction Form a conserved structural backbone for the protein, resulting in greater evolutionary flexibility at other sites.