6,925 research outputs found
On the models of nonlocal nonlinear optics
We show that under certain assumptions a general model of nonlocal nonlinear
response in 1+1-dimension is equivalent to the model considered by Krolikowski
and Bang for a Kerr-type medium. We derive the limit of weak nonlocality in
high frequency regime and discuss the integrable cases.Comment: 6 page
The single currency and European citizenship
We could expect that the introduction of the single currency had been accompanied by a significant share of studies and researches about the implications and impacts of such a watershed event on European citizenship. On the contrary, we soon discover to be facing a paradox, which could be phrased as follows: while the purpose of building European citizenship is the very rationale for the project of the single currency, the Scholars – but also the policy community – have mostly underestimated if not neglected this relation, both in terms of public policy making and discourse and of interpretation and forecasting. As a consequence of all of that, relevant features of the single currency happened to remain hidden, poorly considered and almost not thematized. In order to fill this gap, the first part of this article will present the main findings emerged from a documentary research conducted by FONDACA between 2010 and 2011, aimed at mapping the existing academic and policy thematizations about the hidden dimensions of the euro. The second part will be devoted to define “the other side of the coin” as an empirical phenomenon
Symmetry constraints for real dispersionless Veselov-Novikov equation
Symmetry constraints for dispersionless integrable equations are discussed.
It is shown that under symmetry constraints the dispersionless Veselov-Novikov
equation is reduced to the 1+1-dimensional hydrodynamic type systems.Comment: 14 pages, no figures, to appear on Fund.Prikl.Mat. (russian version),
Jour.Math.Sciences (english version
Beyond key velocity: Continuous sensing for expressive control on the Hammond Organ and Digital keyboards
In this thesis we seek to explore the potential for continuous key position to be
used as an expressive control in keyboard musical instruments, and how preexisting
skills can be adapted to leverage this additional control. Interaction between
performer and sound generation on a keyboard instrument is often restricted
to a number of discrete events on the keys themselves (notes onsets and
offsets), while complementary continuous control is provided via additional interfaces,
such as pedals, modulation wheels and knobs. The rich vocabulary of
gestures that skilled performers can achieve on the keyboard is therefore often
simplified to a single, discrete velocity measurement. A limited number of acoustical
and electromechanical keyboard instruments do, however, present affordances
of continuous key control, so that the role of the key is not limited to delivering
discrete events, but its instantaneous position is, to a certain extent, an element of
expressive control. Recent evolutions in sensing technologies allow to leverage continuous
key position as an expressive element in the sound generation of digital
keyboard musical instruments.
We start by exploring the expression available on the keys of the Hammond
organ, where nine contacts are closed at different points of the key throw for each
key onset and we find that the velocity and the percussiveness of the touch affect
the way the contacts close and bounce, producing audible differences in the onset
transient of each note.
We develop an embedded hardware and software environment for low-latency
sound generation controlled by continuous key position, which we use to create
two digital keyboard instruments. The first of these emulates the sound of a Hammond
and can be controlled with continuous key position, so that it allows for
arbitrary mapping between the key position and the nine virtual contacts of the
digital sound generator. A study with 10 musicians shows that, when exploring
the instrument on their own, the players can appreciate the differences between
different settings and tend to develop a personal preference for one of them. In the
second instrument, continuous key position is the fundamental means of expression:
percussiveness, key position and multi-key gestures control the parameters
of a physical model of a flute. In a study with 6 professional musicians playing
this instrument we gather insights on the adaptation process, the limitations of the
interface and the transferability of traditional keyboard playing techniques
Stochastic vortex dynamics in two-dimensional easy-plane ferromagnets: Multiplicative versus additive noise
We study how thermal fluctuations affect the dynamics of vortices in the
two-dimensional classical, ferromagnetic, anisotropic Heisenberg model
depending on their additive or multiplicative character. Using a collective
coordinate theory, we analytically show that multiplicative noise, arising from
fluctuations in the local field term of the Landau-Lifshitz equations, and
Langevin-like additive noise both have the same effect on vortex dynamics
(within a very plausible assumption consistent with the collective coordinate
approach). This is a non-trivial result, as multiplicative and additive noises
usually modify the dynamics quite differently. We also carry out numerical
simulations of both versions of the model finding that they indeed give rise to
very similar vortex dynamics.Comment: 10 pages, 6 figure
The Colombian conflict: a description of a mental health program in the Department of Tolima.
Colombia has been seriously affected by an internal armed conflict for more than 40 years affecting mainly the civilian population, who is forced to displace, suffers kidnapping, extortion, threats and assassinations. Between 2005 and 2008, Médecins Sans Frontières-France provided psychological care and treatment in the region of Tolima, a strategic place in the armed conflict. The mental health program was based on a short-term multi-faceted treatment developed according to the psychological and psychosomatic needs of the population. Here we describe the population attending during 2005-2008, in both urban and rural settings, as well as the psychological treatment provided during this period and its outcomes.We observed differences between the urban and rural settings in the traumatic events reported, the clinical expression of the disorders, the disorders diagnosed, and their severity. Although the duration of the treatment was limited due to security reasons and access difficulties, patient condition at last visit improved in most of the patients. These descriptive results suggest that further studies should be conducted to examine the role of short-term psychotherapy, adapted specifically to the context, can be a useful tool to provide psychological care to population affected by an armed conflict
Super-diffusion versus competitive advection: a simulation
Magnetic element tracking is often used to study the transport and diffusion
of the magnetic field on the solar photosphere. From the analysis of the
displacement spectrum of these tracers, it has been recently agreed that a
regime of super-diffusivity dominates the solar surface. Quite habitually this
result is discussed in the framework of fully developed turbulence. But the
debate whether the super-diffusivity is generated by a turbulent dispersion
process, by the advection due to the convective pattern, or by even another
process, is still open, as is the question about the amount of diffusivity at
the scales relevant to the local dynamo process. To understand how such
peculiar diffusion in the solar atmosphere takes places, we compared the
results from two different data-sets (ground-based and space-borne) and
developed a simulation of passive tracers advection by the deformation of a
Voronoi network. The displacement spectra of the magnetic elements obtained by
the data-sets are consistent in retrieving a super-diffusive regime for the
solar photosphere, but the simulation also shows a super-diffusive displacement
spectrum: its competitive advection process can reproduce the signature of
super-diffusion. Therefore, it is not necessary to hypothesize a totally
developed turbulence regime to explain the motion of the magnetic elements on
the solar surface
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