1,048 research outputs found
Statistical Mechanics of finite arrays of coupled bistable elements
We discuss the equilibrium of a single collective variable characterizing a
finite set of coupled, noisy, bistable systems as the noise strength, the size
and the coupling parameter are varied. We identify distinct regions in
parameter space. The results obtained in prior works in the asymptotic infinite
size limit are significantly different from the finite size results. A
procedure to construct approximate 1-dimensional Langevin equation is adopted.
This equation provides a useful tool to understand the collective behavior even
in the presence of an external driving force
Z-Axis Meandering Patch Antenna and Fabrication Thereof
Apparatus and techniques described herein can include antenna configurations and related fabrication. For example, a Z-axis meandering antenna configuration can be fabricated, such as by forming a dielectric substrate extending in two dimensions and defining an undulating region extending out of a plane defined by the two dimensions; and forming at least one conductive region following a contour of the dielectric substrate including at least a portion of the undulating region. The at least one conductive region can follow the contour of the dielectric substrate, such as including a first conductive region on a first layer, and a second conductive region on another layer separate from the first conductive region of the first conductive layer
Two-state theory of nonlinear Stochastic Resonance
An amenable, analytical two-state description of the nonlinear population
dynamics of a noisy bistable system driven by a rectangular subthreshold signal
is put forward. Explicit expressions for the driven population dynamics, the
correlation function (its coherent and incoherent part), the signal-to-noise
ratio (SNR) and the Stochastic Resonance (SR) gain are obtained. Within a
suitably chosen range of parameter values this reduced description yields
anomalous SR-gains exceeding unity and, simultaneously, gives rise to a
non-monotonic behavior of the SNR vs. the noise strength. The analytical
results agree well with those obtained from numerical solutions of the Langevin
equation.Comment: 4 pages, 1 figur
Nemo phosphorylates Eyes absent and enhances output from the Eya-Sine oculis transcriptional complex during Drosophila retinal determination
AbstractThe retinal determination gene network comprises a collection of transcription factors that respond to multiple signaling inputs to direct Drosophila eye development. Previous genetic studies have shown that nemo (nmo), a gene encoding a proline-directed serine/threonine kinase, can promote retinal specification through interactions with the retinal determination gene network, although the molecular point of cross-talk was not defined. Here, we report that the Nemo kinase positively and directly regulates Eyes absent (Eya). Genetic assays show that Nmo catalytic activity enhances Eya-mediated ectopic eye formation and potentiates induction of the Eya-Sine oculis (So) transcriptional targets dachshund and lozenge. Biochemical analyses demonstrate that Nmo forms a complex with and phosphorylates Eya at two consensus mitogen-activated protein kinase (MAPK) phosphorylation sites. These same sites appear crucial for Nmo-mediated activation of Eya function in vivo. Thus, we propose that Nmo phosphorylation of Eya potentiates its transactivation function to enhance transcription of Eya-So target genes during eye specification and development
Tuning the program transformers from LCC to PDL
ISBN del número: 978-1-84890-274-9This work proposes an alternative definition of the so-called program transformers
used to obtain reduction axioms in the Logic of Communication and
Change (LCC). Our proposal uses an elegant matrix treatment of Brzozowski’s
equational method instead of Kleene’s translation from finite automata to regular
expressions. The two alternatives are shown to be equivalent, with Brzozowski’s
method having the advantage of generating smaller expressions for
models with average connectivity
Hi-Res activity recognition system based on EEG and WoT
Nowadays, the recognition of physical activity (PA)
is a well-known problem with many solutions. Sev eral kind of algorithms, using MEMS sensors, al low determine the most likely activity. Indeed,
these applications work well when physical activity
is performed for long periods of time and steadily.
However, indoors, these systems are not entirely
suitable and have several problems. In this paper,
thanks to the introduction of new context infor mation, such as EEG, and through communication
between WoT based elements interface at home,
it would be possible to perform a more accurate
and low-level recognition. By using uPnP proto col and additional services, information from other
smart housing elements with user device itself can
be shared, enriching traditional systems based on
ac-celerometry.Ministerio de Economía y Competitividad TIN2009-14378-C02-01Junta de Andalucía TIC-805
Combination of stable isotope analysis and chemometrics to discriminate geoclimatically and temporally the virgin olive oils from three mediterranean countries
The knowledge of the isotopic composition of virgin olive oil (VOO) allows the evaluation of authenticity and geographical origin, being an important tool against fraud. This study aimed to assess if VOOs produced in three Mediterranean regions could be discriminated on the basis of multivariate statistical analysis of geoclimatic and isotopic data. A total of 138 geo-referenced VOO samples from Portugal, France and Turkey from two different cultivation years were collected. The isotopic composition (δ13C, δ2H and δ18O) of VOOs was obtained using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA-IRMS). One-way analysis of variance for δ13C, δ2H and δ18O showed some significant differences either between crop years or geoclimatic conditions. Based on multiple regression analyses using meteorological and geographical parameters, a meteoric water line for olive oil from Portugal, France and Turkey, in two harvest years, were created to assess the impact of climate change on their δ2H and δ18O values. Principal component analysis and Linear Discriminant Analysis, used to sort samples according to geoclimatic origin, performed best for French and Portuguese olive oils. In light of the results, multivariate isotopic analysis of VOO samples may discriminate not only between geoclimatic regions but also among cultivation years
Microcanonical quantum fluctuation theorems
Previously derived expressions for the characteristic function of work
performed on a quantum system by a classical external force are generalized to
arbitrary initial states of the considered system and to Hamiltonians with
degenerate spectra. In the particular case of microcanonical initial states
explicit expressions for the characteristic function and the corresponding
probability density of work are formulated. Their classical limit as well as
their relations to the respective canonical expressions are discussed. A
fluctuation theorem is derived that expresses the ratio of probabilities of
work for a process and its time reversal to the ratio of densities of states of
the microcanonical equilibrium systems with corresponding initial and final
Hamiltonians.From this Crooks-type fluctuation theorem a relation between
entropies of different systems can be derived which does not involve the time
reversed process. This entropy-from-work theorem provides an experimentally
accessible way to measure entropies.Comment: revised and extended versio
The activated torsion oscillation magnetometer
The activated torsion oscillation magnetometer exploits the mechanical
resonance of a cantilever beam, driven by the torque exerted on the sample by
an ac field applied perpendicularly to the film plane. We describe a model for
the cantilever dynamics which leads to the calculation of the cantilever
dynamic profile and allows the mechanical sensitivity of the instrument to be
expressed in terms of the minimum electronically detectable displacement. We
have developed a capacitance detector of small oscillations which is able to
detect displacements of the order of 0.1 nm. We show that sensitivities of the
order of 0.5(10-11 Am2 can be in principle achieved. We will subsequently
describe the main features of the ATOM prototype which we have built and
tested, with particular attention to the design solutions which have been
adopted in order to reduce the effects of parasitic vibrations due either to
acoustic noise, originating from the ac field coil, or to eddy currents in the
capacitor electrodes. The instrument is mounted in a continuous flow cryostat
and can work in the 4.2-300 K temperature range. Finally, we will show that our
experimental set-up has a second mode of operation, named Torsion Induction
Magnetometer (TIM).Comment: Invited Talk at the Moscow International Symposium on Magnetism, 2002
to appear in the J. Mag. Mag. Mat Revised versio
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