55,021 research outputs found
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Interrogating cellular perception and decision making with optogenetic tools.
Optogenetics promises to deepen our understanding of how cells perceive and respond to complex and dynamic signals and how this perception regulates normal and abnormal function. In this study, we present our vision for how these nascent tools may transform our view of fundamental cell biological processes
Making information accessible for the conservation and use of biodiversity. A novel initiative to facilitate access to information and use of agricultural and tree biodiversity
Poster presented at Science Week 2014 - Bioversity International HQ, Rome (Italy), 24-27 Feb 201
Quantum Communication in Spin Systems With Long-Range Interactions
We calculate the fidelity of transmission of a single qubit between distant
sites on semi-infinite and finite chains of spins coupled via the magnetic
dipole interaction. We show that such systems often perform better than their
Heisenberg nearest-neighbour coupled counterparts, and that fidelities closely
approaching unity can be attained between the ends of finite chains without any
special engineering of the system, although state transfer becomes slow in long
chains. We discuss possible optimization methods, and find that, for any
length, the best compromise between the quality and the speed of the
communication is obtained in a nearly uniform chain of 4 spins.Comment: 15 pages, 8 eps figures, updated references, corrected text and
corrected figs. 1, 4 and
A Solid State Pulsed Coagulating Diathermy Instrument
Solid state pulsed coagulating diathermy instrumen
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Numerical modelling of microwave sintering of lunar simulants under near lunar atmospheric condition
Asymptotic analysis of spatially inhomogeneous stiff and ultra-stiff cosmologies
We calculate analytically the past asymptotic decay rates close to an initial
singularity in general G_0 spatially inhomogeneous perfect fluid models with an
effective equation of state which is stiff or ultra-stiff (i.e., ). These results are then supported by numerical simulations in a special
class of G_2 cosmological models. Our analysis confirms and extends the BKL
conjectures and lends support to recent isotropization results in cosmological
models of current interest (with ).Comment: Accepted by CQ
Modified Gravity Makes Galaxies Brighter
We investigate the effect of modifed gravity with screening mechanisms, such
as the chameleon or symmetron models, upon the structure of main sequence
stars. We find that unscreened stars can be significantly more luminous and
ephemeral than their screened doppelgangers. By embedding these stars into
dwarf galaxies, which can be unscreened for values of the parameters not yet
ruled out observationally, we show that the cumulative effect of their
increased luminosity can enhance the total galactic luminosity. We estimate
this enhancement and find that it can be considerable given model parameters
that are still under experimental scrutiny. By looking for systematic offsets
between screened dwarf galaxies in clusters and unscreened galaxies in voids,
these effects could form the basis of an independent observational test that
can potentially lower the current experimental bounds on the model independent
parameters of these theories by and order of magnitude or more.Comment: 16 pages, six figure
Structural dynamic interaction with solar tracking control for evolutionary Space Station concepts
The sun tracking control system design of the Solar Alpha Rotary Joint (SARJ) and the interaction of the control system with the flexible structure of Space Station Freedom (SSF) evolutionary concepts are addressed. The significant components of the space station pertaining to the SARJ control are described and the tracking control system design is presented. Finite element models representing two evolutionary concepts, enhanced operations capability (EOC) and extended operations capability (XOC), are employed to evaluate the influence of low frequency flexible structure on the control system design and performance. The design variables of the control system are synthesized using a constrained optimization technique to meet design requirements, to provide a given level of control system stability margin, and to achieve the most responsive tracking performance. The resulting SARJ control system design and performance of the EOC and XOC configurations are presented and compared to those of the SSF configuration. Performance limitations caused by the low frequency of the dominant flexible mode are discussed
Cotunneling drag effect in Coulomb-coupled quantum dots
In Coulomb drag, a current flowing in one conductor can induce a voltage
across an adjacent conductor via the Coulomb interaction. The mechanisms
yielding drag effects are not always understood, even though drag effects are
sufficiently general to be seen in many low-dimensional systems. In this
Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot
(CC-DQD) and, through both experimental and theoretical arguments, identify
cotunneling as essential to obtaining a correct qualitative understanding of
the drag behavior.Comment: Main text: 5 pages, 5 figures; SM: 11 pages, 5 figures, 1 tabl
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