2,690 research outputs found
Intranasal insulin to improve developmental delay in children with 22q13 deletion syndrome: an exploratory clinical trial
Background: The 22q13 deletion syndrome (Phelan–
McDermid syndrome) is characterised by a global
developmental delay, absent or delayed speech, generalised
hypotonia, autistic behaviour and characteristic
phenotypic features. Intranasal insulin has been shown to
improve declarative memory in healthy adult subjects and
in patients with Alzheimer disease.
Aims: To assess if intranasal insulin is also able to
improve the developmental delay in children with 22q13
deletion syndrome.
Methods: We performed exploratory clinical trials in six
children with 22q13 deletion syndrome who received
intranasal insulin over a period of 1 year. Short-term
(during the first 6 weeks) and long-term effects (after
12 months of treatment) on motor skills, cognitive
functions, or autonomous functions, speech and communication,
emotional state, social behaviour, behavioural
disorders, independence in daily living and education were
assessed.
Results: The children showed marked short-term
improvements in gross and fine motor activities, cognitive
functions and educational level. Positive long-term effects
were found for fine and gross motor activities, nonverbal
communication, cognitive functions and autonomy.
Possible side effects were found in one patient who
displayed changes in balance, extreme sensitivity to touch
and general loss of interest. One patient complained of
intermittent nose bleeding.
Conclusions: We conclude that long-term administration
of intranasal insulin may benefit motor development,
cognitive functions and spontaneous activity in children
with 22q13 deletion syndrome
Reciprocally-rotating Velocity Obstacles
Modern multi-agent systems frequently use high-level planners to extract basic
paths for agents, and then rely on local collision avoidance to ensure that the agents reach
their destinations without colliding with one another or dynamic obstacles. One
state-of-the-art local collision avoidance technique is Optimal Reciprocal Colli- sion Avoidance
(ORCA). Despite being fast and efficient for circular-shaped agents, ORCA may deadlock when
polygonal shapes are used. To address this shortcom- ing, we introduce Reciprocally-Rotating
Velocity Obstacles (RRVO). RRVO extends ORCA by introducing a notion of rotation. This
extension permits more realistic motion than ORCA for polygonally-shaped agents and does not
suffer from as much deadlock. In this thesis, we present the theory of RRVO and show empirically
that it does not suffer from the deadlock issue ORCA has, that it permits agents to
reach goals faster, and that it has a comparable collision rate at the cost of some
performance overhead
Controlling induced coherence for quantum imaging
Induced coherence in parametric down-conversion between two coherently pumped
nonlinear crystals that share a common idler mode can be used as an imaging
technique. Based on the interference between the two signal modes of the
crystals, an image can be reconstructed. By obtaining an expression for the
interference pattern that is valid in both the low- and the high-gain regimes
of parametric down-conversion, we show how the coherence of the light emitted
by the two crystals can be controlled. With our comprehensive analysis we
provide deeper insight into recent discussions about the application of induced
coherence to imaging in different regimes. Moreover, we propose a scheme for
optimizing the visibility of the interference pattern so that it directly
corresponds to the degree of coherence of the light generated in the two
crystals. We find that this scheme leads in the high-gain regime to a
visibility arbitrarily close to unity.Comment: 9 pages, 4 figure
Double Bragg diffraction: A tool for atom optics
The use of retro-reflection in light-pulse atom interferometry under
microgravity conditions naturally leads to a double-diffraction scheme. The two
pairs of counterpropagating beams induce simultaneously transitions with
opposite momentum transfer that, when acting on atoms initially at rest, give
rise to symmetric interferometer configurations where the total momentum
transfer is automatically doubled and where a number of noise sources and
systematic effects cancel out. Here we extend earlier implementations for Raman
transitions to the case of Bragg diffraction. In contrast with the
single-diffraction case, the existence of additional off-resonant transitions
between resonantly connected states precludes the use of the adiabatic
elimination technique. Nevertheless, we have been able to obtain analytic
results even beyond the deep Bragg regime by employing the so-called "method of
averaging," which can be applied to more general situations of this kind. Our
results have been validated by comparison to numerical solutions of the basic
equations describing the double-diffraction process.Comment: 26 pages, 20 figures; minor changes to match the published versio
The phase sensitivity of a fully quantum three-mode nonlinear interferometer
We study a nonlinear interferometer consisting of two consecutive parametric
amplifiers, where all three optical fields (pump, signal and idler) are treated
quantum mechanically, allowing for pump depletion and other quantum phenomena.
The interaction of all three fields in the final amplifier leads to an
interference pattern from which we extract the phase uncertainty. We find that
the phase uncertainty oscillates around a saturation level that decreases as
the mean number of input pump photons increases. For optimal interaction
strengths, we also find a phase uncertainty below the shot-noise level and
obtain a Heisenberg scaling . This is in contrast to the conventional
treatment within the parametric approximation, where the Heisenberg scaling is
observed as a function of the number of down-converted photons inside the
interferometer.Comment: 8 pages, 7 figure
Diastereofacial selectivity in reactions of substituted cyclohexyl radicals. An experimental and theoretical study
Measurement of the Photon-Plasmon Coupling Phase
Scattering processes have played a crucial role in the development of quantum
theory. In the field of optics, scattering phase shifts have been utilized to
unveil interesting forms of light-matter interactions. Here, we investigate the
mode-coupling phase of single photons to surface plasmon polaritons in a
quantum plasmonic tritter. We observe that the coupling process induces a phase
jump that occurs when photons scatter into surface plasmons and vice versa.
This interesting coupling phase dynamics is of particular relevance for quantum
plasmonic experiments. Furthermore, it is demonstrated that this photon-plasmon
interaction can be modeled through a quantum-mechanical tritter. We show that
the visibility of a double-slit and a triple-slit interference patterns are
convenient observables to characterize the interaction at a slit and determine
the coupling phase. Our accurate and simple model of the interaction, validated
by simulations and experiments, has important implications not only for quantum
plasmonic interference effects, but is also advantageous to classical
applications
Hierarchical Spatio-Temporal Morphable Models for Representation of complex movements for Imitation Learning
Imitation learning is a promising technique for teaching robots complex movement sequences. One key problem in this area is the transfer of perceived movement characteristics from perception to action. For the solution of this problem, representations are required that are suitable for the analysis and the synthesis of complex action sequences. We describe the method of Hierarchical Spatio-Temporal Morphable Models that allows an automatic segmentation of movements sequences into movement primitives, and a modeling of these primitives by morphing between a set of prototypical trajectories. We use HSTMMs in an imitation learning task for human writing movements. The models are learned from recorded trajectories and transferred to a human-like robot arm. Due to the generalization proper- ties of our movement representation, the arm is capable of synthesizing new writing movements with only a few learning examples
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