7,266 research outputs found
Review article
In eukaryotic cells, the trans-Golgi network (TGN) serves as a platform for secretory cargo sorting and trafficking. In recent years, it has become evident that a complex network of lipid-lipid and lipid-protein interactions contributes to these key functions. This review addresses the role of lipids at the TGN with a particular emphasis on sphingolipids and diacylglycerol. We further highlight how these lipids couple secretory cargo sorting and trafficking for spatiotemporal coordination of protein transport to the plasma membrane
Development of UHF radiometer
A wideband multifrequency UHF radiometer was initially developed to operate in the 500 to 710 MHz frequency range for the remote measurement of ocean water salinity. However, radio-frequency interference required a reconfiguration to operate in the single-frequency radio astronomy band of 608 to 614 MHz. Details of the radiometer development and testing are described. Flight testing over variable terrain provided a performance comparison of the UHF radiometer with an L-band radiometer for remote sensing of geophysical parameters. Although theoretically more sensitive, the UHF radiometer was found to be less desirable in practice than the L-band radiometer
Quantum Darwinism in quantum Brownian motion: the vacuum as a witness
We study quantum Darwinism -- the redundant recording of information about a
decohering system by its environment -- in zero-temperature quantum Brownian
motion. An initially nonlocal quantum state leaves a record whose redundancy
increases rapidly with its spatial extent. Significant delocalization (e.g., a
Schroedinger's Cat state) causes high redundancy: many observers can measure
the system's position without perturbing it. This explains the objective (i.e.
classical) existence of einselected, decoherence-resistant pointer states of
macroscopic objects.Comment: 5 page
System Size Dependence of Particle Production at the SPS
Recent results on the system size dependence of net-baryon and hyperon
production as measured at the CERN SPS are discussed. The observed Npart
dependences of yields, but also of dynamical properties, such as average
transverse momenta, can be described in the context of the core corona
approach. Other observables, such as antiproton yields and net-protons at
forward rapidities, do not follow the predictions of this model. Possible
implications for a search for a critical point in the QCD phase diagram are
discussed. Event-by-event fluctuations of the relative core to corona source
contributions might influence fluctuation observables (e.g. multiplicity
fluctuations). The magnitude of this effect is investigated.Comment: 10 pages, 4 figurs. Proceedings of the 6th International Workshop on
Critical Point and Onset of Deconfinement in Dubna, Aug. 201
Nash Codes for Noisy Channels
This paper studies the stability of communication protocols that deal with
transmission errors. We consider a coordination game between an informed sender
and an uninformed decision maker, the receiver, who communicate over a noisy
channel. The sender's strategy, called a code, maps states of nature to
signals. The receiver's best response is to decode the received channel output
as the state with highest expected receiver payoff. Given this decoding, an
equilibrium or "Nash code" results if the sender encodes every state as
prescribed. We show two theorems that give sufficient conditions for Nash
codes. First, a receiver-optimal code defines a Nash code. A second, more
surprising observation holds for communication over a binary channel which is
used independently a number of times, a basic model of information
transmission: Under a minimal "monotonicity" requirement for breaking ties when
decoding, which holds generically, EVERY code is a Nash code.Comment: More general main Theorem 6.5 with better proof. New examples and
introductio
Phenomenological Models of Socio-Economic Network Dynamics
We study a general set of models of social network evolution and dynamics.
The models consist of both a dynamics on the network and evolution of the
network. Links are formed preferentially between 'similar' nodes, where the
similarity is defined by the particular process taking place on the network.
The interplay between the two processes produces phase transitions and
hysteresis, as seen using numerical simulations for three specific processes.
We obtain analytic results using mean field approximations, and for a
particular case we derive an exact solution for the network. In common with
real-world social networks, we find coexistence of high and low connectivity
phases and history dependence.Comment: 11 pages, 8 figure
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