10,837 research outputs found
Energy-scales convergence for optimal and robust quantum transport in photosynthetic complexes
Underlying physical principles for the high efficiency of excitation energy
transfer in light-harvesting complexes are not fully understood. Notably, the
degree of robustness of these systems for transporting energy is not known
considering their realistic interactions with vibrational and radiative
environments within the surrounding solvent and scaffold proteins. In this
work, we employ an efficient technique to estimate energy transfer efficiency
of such complex excitonic systems. We observe that the dynamics of the
Fenna-Matthews-Olson (FMO) complex leads to optimal and robust energy transport
due to a convergence of energy scales among all important internal and external
parameters. In particular, we show that the FMO energy transfer efficiency is
optimum and stable with respect to the relevant parameters of environmental
interactions and Frenkel-exciton Hamiltonian including reorganization energy
, bath frequency cutoff , temperature , bath spatial
correlations, initial excitations, dissipation rate, trapping rate, disorders,
and dipole moments orientations. We identify the ratio of \lambda T/\gamma\*g
as a single key parameter governing quantum transport efficiency, where g is
the average excitonic energy gap.Comment: minor revisions, removing some figures, 19 pages, 19 figure
The teacher as action researcher : Using technology to capture pedagogic form
The paper argues that we make best use of learning technologies if we begin with an understanding of educational problems, and use this analysis to target the solutions we should be demanding from technology. The focus is to address the issue from the perspective of teachers and lecturers – the 'teaching community', and to consider how they could become the experimental innovators and reflective practitioners who will use technology well. Teachers could become 'action researchers', collaborating to produce their own development of knowledge about teaching with technology. For this to be possible, they must be able to share that knowledge, and the paper proposes the use of an online learning activity management system (LAMS) as a way of capturing and sharing the pedagogic forms teachers design. An action research approach, like all research, needs a theoretical framework from which to challenge practice, and paper shows how teachers could use the Conversational Framework to design and test an optimally effective learning experience. Examples of 'generic' learning designs illustrate how such approach can help the teaching community rethink their teaching, collectively, and embrace the best of conventional and digital methods. In this way they will be more likely to harness technology to the needs of education, rather than simply search for the problems to which the latest technology is a solution
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MILO : a microarchitecture and logic optimizer
In this report we discuss strengths and weaknesses of logic synthesis systems and describe a system for microarchitectural and logic optimization. Our system uses a set of algorithms for synthesizing SSI/MSI macros from parameterized microarchitecture components. In addition, it uses rules for optimizing both at the microarchitecture and logic level. The system increases designer productivity and requires less design knowledge and experience from circuit engineers
Game Theoretic Analysis of Negotiations under Bankruptcy
We extend the contingent claims framework for the levered firm in explicitly modeling the resolution of financial distress under formal bankruptcy as a non-cooperative game between claimants under the supervision of the bankruptcy judge. The identity of the class of claimants proposing the first reorganization plan is found to be a key determinant of the likelihood of liquidation and of the renegotiated value of claims. Our quantitative results confirm the economic intuition that a bankruptcy design must trade-off the initial priority of claims with the viability of reorganized firms
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