13,274 research outputs found
Frequently hypercyclic bilateral shifts
It is not known if the inverse of a frequently hypercyclic bilateral weighted
shift on is again frequently hypercyclic. We show that the
corresponding problem for upper frequent hypercyclicity has a positive answer.
We characterise, more generally, when bilateral weighted shifts on Banach
sequence spaces are (upper) frequently hypercyclic
Algebras of frequently hypercyclic vectors
We show that the multiples of the backward shift operator on the spaces
, , or , when endowed with coordinatewise
multiplication, do not possess frequently hypercyclic algebras. More generally,
we characterize the existence of algebras of -hypercyclic vectors
for these operators. We also show that the differentiation operator on the
space of entire functions, when endowed with the Hadamard product, does not
possess frequently hypercyclic algebras. On the other hand, we show that for
any frequently hypercyclic operator on any Banach space, is
algebrable for a suitable product, and in some cases it is even strongly
algebrable
Fluorescent nanodiamonds for FRET-based monitoring of a single biological nanomotor FoF1-ATP synthase
Color centers in diamond nanocrystals are a new class of fluorescence markers
that attract significant interest due to matchless brightness, photostability
and biochemical inertness. Fluorescing diamond nanocrystals containing defects
can be used as markers replacing conventional organic dye molecules, quantum
dots or autofluorescent proteins. They can be applied for tracking and
ultrahigh-resolution localization of the single markers. In addition the spin
properties of diamond defects can be utilized for novel magneto-optical imaging
(MOI) with nanometer resolution. We develop this technique to unravel the
details of the rotary motions and the elastic energy storage mechanism of a
single biological nanomotor FoF1-ATP synthase. FoF1-ATP synthase is the enzyme
that provides the 'chemical energy currency' adenosine triphosphate, ATP, for
living cells. The formation of ATP is accomplished by a stepwise internal
rotation of subunits within the enzyme. Previously subunit rotation has been
monitored by single-molecule fluorescence resonance energy transfer (FRET) and
was limited by the photostability of the fluorophores. Fluorescent nanodiamonds
advance these FRET measurements to long time scales.Comment: 10 pages, 4 figure
A Development Environment for Visual Physics Analysis
The Visual Physics Analysis (VISPA) project integrates different aspects of
physics analyses into a graphical development environment. It addresses the
typical development cycle of (re-)designing, executing and verifying an
analysis. The project provides an extendable plug-in mechanism and includes
plug-ins for designing the analysis flow, for running the analysis on batch
systems, and for browsing the data content. The corresponding plug-ins are
based on an object-oriented toolkit for modular data analysis. We introduce the
main concepts of the project, describe the technical realization and
demonstrate the functionality in example applications
Automated Reconstruction of Particle Cascades in High Energy Physics Experiments
We present a procedure for reconstructing particle cascades from event data
measured in a high energy physics experiment. For evaluating the hypothesis of
a specific physics process causing the observed data, all possible
reconstruction versions of the scattering process are constructed from the
final state objects. We describe the procedure as well as examples of physics
processes of different complexity studied at hadron-hadron colliders. We
estimate the performance by 20 microseconds per reconstructed decay vertex, and
0.6 kByte per reconstructed particle in the decay trees.Comment: 8 pages, 2 figures. Submitted to Computational Science & Discover
Concepts, Developments and Advanced Applications of the PAX Toolkit
The Physics Analysis eXpert (PAX) is an open source toolkit for high energy
physics analysis. The C++ class collection provided by PAX is deployed in a
number of analyses with complex event topologies at Tevatron and LHC. In this
article, we summarize basic concepts and class structure of the PAX kernel. We
report about the most recent developments of the kernel and introduce two new
PAX accessories. The PaxFactory, that provides a class collection to facilitate
event hypothesis evolution, and VisualPax, a Graphical User Interface for PAX
objects
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