22,084 research outputs found
Omnipresent Maxwell’s demons orchestrate information management in living cells
The development of synthetic biology calls for accurate
understanding of the critical functions that allow
construction and operation of a living cell. Besides
coding for ubiquitous structures, minimal genomes
encode a wealth of functions that dissipate energy in
an unanticipated way. Analysis of these functions
shows that they are meant to manage information
under conditions when discrimination of substrates
in a noisy background is preferred over a simple
recognition process. We show here that many of
these functions, including transporters and the ribosome
construction machinery, behave as would
behave a material implementation of the informationmanaging
agent theorized by Maxwell almost
150 years ago and commonly known as Maxwell’s
demon (MxD). A core gene set encoding these functions belongs to the minimal genome required
to allow the construction of an autonomous cell.
These MxDs allow the cell to perform computations
in an energy-efficient way that is vastly better than
our contemporary computers
Expanding graphs, Ramanujan graphs, and 1-factor perturbations
We construct (k+-1)-regular graphs which provide sequences of expanders by
adding or substracting appropriate 1-factors from given sequences of k-regular
graphs. We compute numerical examples in a few cases for which the given
sequences are from the work of Lubotzky, Phillips, and Sarnak (with k-1 the
order of a finite field). If k+1 = 7, our construction results in a sequence of
7-regular expanders with all spectral gaps at least about 1.52
A Spatial Look at Negative Externalities in Agricultural Landscapes: Seedless Mandarins and Honey Bee Pollination in California
When honey bees transport pollen across citrus orchards they can increase the number of seeds in varieties that remain seedless otherwise. An increase in seeds diminishes the market value of the fruit creating an externality between seedless growers and beekeepers. This paper investigates the efficiency of different policy resolution of this externality including a range of regulated spatial segregations of beekeeping and seedless farming with or without financial compensations. We develop a spatial model of honey foraging behavior to quantify the efficiencies and redistributions of different policies that may be used to correct this market failure. Some of these policies have been implemented others are being currently discussed in policy debates in the California citrus belt. This paper illustrates that quantifying biophysical processes that create externalities is a necessary step towards evaluating the economics efficiency of alternative solutions.Resource /Energy Economics and Policy,
The future of the Belgian Press
Overview of the Belgian print media landscape with comarative approach for Flanders and Walloni
Entanglement in a fermion chain under continuous monitoring
We study the entanglement entropy of the quantum trajectories of a free
fermion chain under continuous monitoring of local occupation numbers. We
propose a simple theory for entanglement entropy evolution from disentangled
and highly excited initial states. It is based on generalized hydrodynamics and
the quasi-particle pair approach to entanglement in integrable systems. We test
several quantitative predictions of the theory against extensive numerics and
find good agreement. In particular, the volume law entanglement is destroyed by
the presence of arbitrarily weak measurement.Comment: 18 pages, 8 figures, 2 new figure
Gravitational wave energy spectrum of hyperbolic encounters
The emission of gravitational waves is studied for a system of massive
objects interacting on hyperbolic orbits within the quadrupole approximation
following the work of Capozziello et al. Here we focus on the derivation of an
analytic formula for the energy spectrum of the emitted waves. We checked
numerically that our formula is in agreement with the two limiting cases for
which results were already available: for the eccentricity {\epsilon} = 1, the
parabolic case whose spectrum was computed by Berry and Gair, and the large
{\epsilon} limit with the formula given by Turner.Comment: 9 pages, 4 figures, Accepted for publication in Physical Review
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