121,012 research outputs found
Can re-entrance be observed in force induced transitions?
A large conformational change in the reaction co-ordinate and the role of the
solvent in the formation of base-pairing are combined to settle a long standing
issue {\it i.e.} prediction of re-entrance in the force induced transition of
DNA. A direct way to observe the re-entrance, i.e a strand goes to the closed
state from the open state and again to the open state with temperature, appears
difficult to be achieved in the laboratory. An experimental protocol (in direct
way) in the constant force ensemble is being proposed for the first time that
will enable the observation of the re-entrance behavior in the
force-temperature plane. Our exact results for small oligonucleotide that forms
a hairpin structure provide the evidence that re-entrance can be observed.Comment: 12 pages and 5 figures (RevTex4). Accepted in Europhys Lett. (2009
From open resources to educational opportunity
Since MIT’s bold announcement of the OpenCourseWare initiative in 2001, the content of over 700 of its courses have been published on the Web and made available for free to the world. Important infrastructure initiatives have also been launched recently with a view to enabling the sustainable implementation of these educational programmes, through strengthening organizational capacity as well as through building open, standards‐based technology. Each of these initiatives point to a rich palette of transformational possibilities for education; together with the growing open source movement, they offer glimpses of a sustainable ecology of substantial and quality educational resources. This discussion piece will highlight some of the educational opportunity presented by MIT’s current information technology‐enabled educational agenda and related initiatives, along with their strategic underpinnings and implications. It will address various dimensions of their impact on the form and function of education. It will examine how these ambitious programmes achieve a vision characterized by an abundance of sustainable, transformative educational opportunities, not merely pervasive technology
The Contribution of Hot Electron Spin Polarization to the Magnetotransport in a Spin-Valve Transistor at Finite Temperatures
The effect of spin mixing due to thermal spin waves and temperature
dependence of hot electron spin polarization to the collector current in a
spin-valve transistor has been theoretically explored. We calculate the
collector current as well as the temperature dependence of magnetocurrent at
finite temperatures to investigate the relative importance of spin mixing and
hot electron spin polarization. In this study the inelastic scattering events
in ferromagnetic layers have been taken into account to explore our interests.
The theoretical calculations suggest that the temperature dependence of hot
electron spin polarization has substantial contribution to the magnetotransport
in the spin-valve transistor.Comment: 8 pages and 6 figure
A distributed directory scheme for information access in mobile computers
In this paper, we discuss the design aspects of a dynamic distributed directory scheme (DDS) to facilitate efficient and transparent access to information files in mobile environments. The proposed directory interface enables users of mobile computers to view a distributed file system on a network of computers as a globally shared file system. In order to counter some of the limitations of wireless communications, we propose improvised invalidation schemes that avoid false sharing and ensure uninterrupted usage under disconnected and low bandwidth conditions
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