2,903 research outputs found
Transitions in auditory rehabilitation with bone conductive implant (bci)
Background: The bone conductive implants (BCI) are nowadays a reliable alternative for rehabilitation of specific forms of hearing loss, i.e. conductive, mixed or single sided deafness (SSD). Aims/Objective: To analyse the various factors in play when considering an auditory rehabilitation with a bone-conductive device (BCI). Materials and Methods: The clinical charts of subjects who underwent BCI application at the same Implanting Center from 2005 to 2018 were retrieved analysing also the reason for eventual explantation and the alternative option (transition) for hearing rehabilitation. Results: Nine BAHA Compact, 4 BAHA Intenso, 21 BAHA Divino, 3 BAHA BP100, 4 Ponto, 2 Sophono, 5 Bonebridge, 5 BAHA5 Attract; 11 BAHA5 Connect were used in 12 unilateral COM; 16 bilateral COM; 3 unilateral cholesteatoma; 6 bilateral cholesteatoma; 2 unilateral otosclerosis; 5 bilateral otosclerosis; 9 congenital malformations; 6 major otoneurosurgical procedures; 5 sudden deafness. Explantation was necessary for five subjects. Conclusions: Middle ear pathology and sequels from surgery represent the most common reason for BCI implantation, both in unilateral and in bilateral cases. Transition from one implantable device to another one can be predictable, mostly when explantation is necessary. Significance: The role of BCI for rehabilitation in middle ear pathology may be extremely important
QoS monitoring in real-time streaming overlays based on lock-free data structures
AbstractPeer-to-peer streaming is a well-known technology for the large-scale distribution of real-time audio/video contents. Delay requirements are very strict in interactive real-time scenarios (such as synchronous distance learning), where playback lag should be of the order of seconds. Playback continuity is another key aspect in these cases: in presence of peer churning and network congestion, a peer-to-peer overlay should quickly rearrange connections among receiving nodes to avoid freezing phenomena that may compromise audio/video understanding. For this reason, we designed a QoS monitoring algorithm that quickly detects broken or congested links: each receiving node is able to independently decide whether it should switch to a secondary sending node, called "fallback node". The architecture takes advantage of a multithreaded design based on lock-free data structures, which improve the performance by avoiding synchronization among threads. We will show the good responsiveness of the proposed approach on machines with different computational capabilities: measured times prove both departures of nodes and QoS degradations are promptly detected and clients can quickly restore a stream reception. According to PSNR and SSIM, two well-known full-reference video quality metrics, QoE remains acceptable on receiving nodes of our resilient overlay also in presence of swap procedures
Segregation with Social Linkages: Evaluating Schelling's Model with Networked Individuals
This paper generalizes the original Schelling (1969, 1971a,b, 2006) model of
racial and residential segregation to a context of variable externalities due
to social linkages. In a setting in which individuals' utility function is a
convex combination of a heuristic function a la Schelling, of the distance to
friends, and of the cost of moving, the prediction of the original model gets
attenuated: the segregation equilibria are not the unique solutions. While the
cost of distance has a monotonic pro-status-quo effect, equivalent to that of
models of migration and gravity models, if friends and neighbours are formed
following independent processes the location of friends in space generates an
externality that reinforces the initial configuration if the distance to
friends is minimal, and if the degree of each agent is high. The effect on
segregation equilibria crucially depends on the role played by network
externalities.Comment: 38 pages, 24 figure
Exploiting Robot Redundancy for Online Learning and Control
Accurate trajectory tracking in the task space is critical in many robotics applications. Model-based robot controllers are able to ensure very good tracking but lose effectiveness in the presence of model uncertainties. On the other hand, online learning-based control laws can handle poor dynamic modeling, as long as prediction errors are kept small and decrease over time. However, in the case of redundant robots directly controlled in the task space, this condition is not usually met. We present an online learning-based control framework that exploits robot redundancy so as to increase the overall performance and shorten the learning transient. The validity of the proposed approach is shown through a comparative study conducted in simulation on a KUKA LWR4+ robot
Implications of the Weak Gravity Conjecture for Tidal Love Numbers of Black Holes
The Weak Gravity Conjecture indicates that extremal black holes in the low
energy effective field theory should be able to decay. This criterion gives
rise to non-trivial constraints on the coefficients of higher-order derivative
corrections to gravity. In this paper, we investigate the tidal deformability
of neutral black holes due to higher-order derivative corrections. As a proof
of concept, we consider a correction of cubic order in the Riemann curvature
tensor. The tidal Love numbers of neutral black holes receive leading-order
corrections from higher-order derivative terms, since black holes in pure
General Relativity have vanishing tidal Love number. We conclude that the
interplay between the tidal deformability of black holes and the Weak Gravity
Conjecture provides useful information about the effective field theory.Comment: 23 pages, 2 figures. v2: matching published versio
Dynamical friction in dark matter superfluids: The evolution of black hole binaries
The theory of superfluid dark matter is characterized by self-interacting
sub-eV particles that thermalize and condense to form a superfluid core in
galaxies. Massive black holes at the center of galaxies, however, modify the
dark matter distribution and result in a density enhancement in their vicinity
known as dark matter spikes. The presence of these spikes affects the evolution
of binary systems by modifying their gravitational wave emission and inducing
dynamical friction effects on the orbiting bodies. In this work, we assess the
role of dynamical friction for bodies moving through a superfluid core enhanced
by a central massive black hole. As a first step, we compute the dynamical
friction force experienced by bodies moving in a circular orbit. Then, we
estimate the gravitational wave dephasing of the binary, showing that the
effect of the superfluid drag force is beyond the reach of space-based
experiments like LISA, contrarily to collisionless dark matter, therefore
providing an opportunity to distinguish these dark matter models.Comment: 36 pages, 7 figure
Non-linearities in the tidal Love numbers of black holes
Tidal Love numbers describe the linear response of a compact object under the
presence of external tidal perturbations, and they are found to vanish exactly
for black holes within General Relativity. In this paper we investigate the
tidal deformability of neutral black holes when non-linearities in the theory
are taken into account. As a case in point, we consider scalar tidal
perturbations on the black hole background, and find that the tidal Love
numbers may be non vanishing depending on the scalar interactions in the bulk
theory. Remarkably, for non-linear sigma models, we find that the tidal Love
numbers vanish to all orders in perturbation theory.Comment: 30 pages. v2: matching version published in PR
Oncoplastic central quadrantectomies
Tumors localized in the central quadrant (centrally located breast tumors) have always represented a challenge for the surgeon because of the critical aesthetical matters related to the nipple-areola complex (NAC). Many years of experience with breast cancer patients treated by using various oncoplastic techniques, has allowed us to develop the modified hemibatwing for the treatment of central breast tumors, where the NAC is involved. Modified hemibatwing-along with the removal of the NAC-is a useful oncoplastic technique and it represents an ideal option for the treatment of central tumors because it assures oncological safety, a reduced surgical timetable and greater aesthetical results
Advanced chondrosarcoma of the pelvis: a rare case of urinary obstruction
Chondrosarcoma is the second most common malignant tumor of the bone with an incidence of 1 in 200.000 per year. Axial skeleton is frequently involved showing poorer oncological outcomes than appendicular one: human pelvis is a site predilection. It is rarely associated to urinary obstruction but according to its localization, it can be frequently linked to compression of pelvic organs as bladder, prostate or bowel. We describe the case of a 52 years old caucasian male with history of advanced pelvic chondrosarcoma and severe hydronephrosis due to total bladder dislocation
Equivalence of nonequilibrium ensembles in turbulence models
Understanding under which conditions it is possible to construct equivalent ensembles is key to advancing our ability to connect microscopic and macroscopic properties of non-equilibrium statisti- cal mechanics. In the case of fluid dynamical systems, a first issue is to test whether different models for viscosity lead to the same macroscopic properties of the fluid systems in different regimes. Such models include, besides the standard choice of constant viscosity, also cases where the time symme- try of the evolution equations is exactly preserved, as it must be in the corresponding microscopic systems, when available. Here a time-reversible dynamics is obtained by imposing the conservation of global observables. We test the equivalence of reversible and irreversible ensembles for the case of a multiscale shell model of turbulence. We verify that the equivalence is obeyed for the mean-values of macroscopic observables, up to an error that vanishes as the system becomes more and more chaotic
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