8,939 research outputs found
Plasma Waves in Anisotropic Superconducting Films Below and Above the Plasma Frequency
We consider wave propagation inside an anisotropic superconducting film
sandwiched between two semi-infinite non-conducting bounding dieletric media
such that along the c-axis, perpendicular to the surfaces, there is a plasma
frequency below the superconducting gap. Propagation is assumed to
be parallel to the surfaces in the dielectric medium, where amplitudes decay
exponentially.Below , the amplitude also evanesces inside the film,
and we retrieve the experimentally measured lower dispersion relation branch,
, and the recently proposed higher frequency
branch, .Above , propagation is of the
guided wave type, i.e., a dispersive plane wave confined inside the film that
reflects into the dielectric interfaces,and the modes are approximately
described by , where
is discussed here.Comment: 26 pages,4 figures.Submitte
PALB2 self-interaction controls homologous recombination.
PALB2 is essential for BRCA2 anchorage to nuclear structures and for homologous recombinational repair of DNA double-strand breaks. Here, we report that the N-terminal coiled-coil motif of PALB2 regulates its self-association and homologous recombination. Monomeric PALB2 shows higher efficiency to bind DNA and promotes RAD51 filament formation with or without the inhibitory effect of Replication Protein A. Moreover, overexpression of the PALB2 coiled-coil domain severely affects RAD51 loading to DNA damage sites suggesting a competition between PALB2 self-interaction and PALB2-BRCA1 interaction. In the presence of DNA damage, the switch between PALB2-PALB2 and PALB2-BRCA1 interactions allows the activation of HR. Controlling HR via PALB2 self-interactions could be important to prevent aberrant recombination in normal conditions and activate DNA repair when required
Community water management and agricultural extension services: effects, impacts and perceptions in the coastal zone of Bangladesh
The coastal region of Bangladesh is prone to natural disasters and these events are expected to worsen as a result of climate change. Combined with anthropogenic factors, these events challenge livelihood opportunities, especially crop production. Waterlogging, tidal activity and the lack of proper drainage facilities are major constraints to agricultural production in these areas.
The CGIAR Research Program on Water, Land and Ecosystems (WLE) tested, at pilot scale, the combination of innovative agricultural technologies with improved water management to overcome these challenges.
This report assesses this intervention by observing the effects, measuring the short-term impacts and understanding the perceptions. The results highlight the need to integrate the interventions into the local context, and acknowledge that institutions and markets need to mature to harness the benefits from innovations. It also underlines the potential of multi-scale interventions combining plot-level and farmer-led innovations, community management and rehabilitation of large schemes
ACME vs PDDL: support for dynamic reconfiguration of software architectures
On the one hand, ACME is a language designed in the late 90s as an
interchange format for software architectures. The need for recon guration at
runtime has led to extend the language with speci c support in Plastik. On the
other hand, PDDL is a predicative language for the description of planning
problems. It has been designed in the AI community for the International
Planning Competition of the ICAPS conferences. Several related works have
already proposed to encode software architectures into PDDL. Existing planning
algorithms can then be used in order to generate automatically a plan that
updates an architecture to another one, i.e., the program of a recon guration.
In this paper, we improve the encoding in PDDL. Noticeably we propose how to
encode ADL types and constraints in the PDDL representation. That way, we can
statically check our design and express PDDL constraints in order to ensure
that the generated plan never goes through any bad or inconsistent
architecture, not even temporarily.Comment: 6\`eme \'edition de la Conf\'erence Francophone sur les Architectures
Logicielles (CAL 2012), Montpellier : France (2012
Ultrafast QND measurements based on diamond-shape artificial atom
We propose a Quantum Non Demolition (QND) read-out scheme for a
superconducting artificial atom coupled to a resonator in a circuit QED
architecture, for which we estimate a very high measurement fidelity without
Purcell effect limitations. The device consists of two transmons coupled by a
large inductance, giving rise to a diamond-shape artificial atom with a logical
qubit and an ancilla qubit interacting through a cross-Kerr like term. The
ancilla is strongly coupled to a transmission line resonator. Depending on the
qubit state, the ancilla is resonantly or dispersively coupled to the
resonator, leading to a large contrast in the transmitted microwave signal
amplitude. This original method can be implemented with state of the art
Josephson parametric amplifier, leading to QND measurements in a few tens of
nanoseconds with fidelity as large as 99.9 %.Comment: 5 pages, 4 figure
Stabilizing control for power converters connected to transmission lines
This paper proposes a switching control strategy for the set-point stabilization of a power converter connected via a transmission line to a resistive load. The strategy employs a Lyapunov function that is directly based on energy considerations of the power converter, as well as of the transmission line described by the telegraph equations. The proposed stabilizing switching control still allows a certain freedom in the choice of the control law, a comparison between a maximum descent strategy and a minimum commutation strategy being discussed on a simple example.
Electrical noise properties in aging materials
The electric thermal noise has been measured in two aging materials, a
colloidal suspension (Laponite) and a polymer (polycarbonate), presenting very
slow relaxation towards equilibrium. The measurements have been performed
during the transition from a fluid-like to a solid-like state for the gel and
after a quench for the polymer. For both materials we have observed that the
electric noise is characterized by a strong intermittency, which induces a
large violation of the Fluctuation Dissipation Theorem (FDT) during the aging
time, and may persist for several hours at low frequency. The statistics of
these intermittent signals and their dependance on the quench speed for the
polymer or on sample concentration for the gel are studied. The results are in
a qualitative agreement with recent models of aging, that predict an
intermittent dynamics.Comment: SPIE Proceeding Journa
Issues of Architectural Description Languages for Handling Dynamic Reconfiguration
Dynamic reconfiguration is the action of modifying a software system at
runtime. Several works have been using architectural specification as the basis
for dynamic reconfiguration. Indeed ADLs (architecture description languages)
let architects describe the elements that could be reconfigured as well as the
set of constraints to which the system must conform during reconfiguration. In
this work, we investigate the ADL literature in order to illustrate how
reconfiguration is supported in four well-known ADLs: pi-ADL, ACME, C2SADL and
Dynamic Wright. From this review, we conclude that none of these ADLs: (i)
addresses the issue of consistently reconfiguring both instances and types;
(ii) takes into account the behaviour of architectural elements during
reconfiguration; and (iii) provides support for assessing reconfiguration,
e.g., verifying the transition against properties.Comment: 6\`eme Conf\'erence francophone sur les architectures logicielles
(CAL'2012), Montpellier : France (2012
Measuring the size of a Schroedinger cat state
We propose a measure for the "size" of a Schroedinger cat state, i.e. a
quantum superposition of two many-body states with (supposedly) macroscopically
distinct properties, by counting how many single-particle operations are needed
to map one state onto the other. This definition gives sensible results for
simple, analytically tractable cases and is consistent with a previous
definition restricted to Greenberger-Horne-Zeilinger-like states. We apply our
measure to the experimentally relevant, nontrivial example of a superconducting
three-junction flux qubit put into a superposition of left- and
right-circulating supercurrent states and find this Schroedinger cat to be
surprisingly small.Comment: 5 pages, 3 figure
- âŠ