14,131 research outputs found
Tube streaming: Modelling collaborative media streaming in urban railway networks
We propose a quality assessment framework for crowdsourced media streaming in urban railway networks. We assume that commuters either tune in to some TV/radio channel, or submit requests for content they desire to watch or listen to, which eventually forms a playlist of videos/podcasts/tunes. Given that connectivity is challenged by the movement of trains and the disconnection that this movement causes, users collabo-ratively download (through cellular and WiFi connections) and share content, in order to maintain undisrupted playback. We model collaborative media streaming for the case of the London Underground train network. The proposed quality assessment framework comprises a utility function which characterises the Quality of Experience (QoE) that users (subjectively) perceive and takes into account all the necessary parameters that affect smooth playback. The framework can be used to assess the media streaming quality in any railway network, after adjusting the related parameters. To the best of our knowledge, this is the first study to quantify the perceptual quality of collaborative media streaming in (underground) railway networks from a modelling perspective, as opposed to a systems perspective. Based on real commuter traces from the London Underground network, we evaluate whether audio and video can be streamed to commuters with acceptable QoE. Our results show that even with very high-speed Internet connection, users still experience disruptions, but a carefully designed collaborative mechanism can result in high levels of perceived QoE even in such disruptive scenarios
Ultrathin, Ultra‐Conformable, and Free‐Standing Tattooable Organic Light‐Emitting Diodes
A novel tattooable, ultrathin, green organic light‐emitting diode (OLED) fabricated on top of commercial temporary tattoo paper, is demonstrated. The transfer mechanism relies on dissolution of the sacrificial layer typically incorporated in paper‐tattoos. The ready‐to‐use device can be stored on the tattoo substrate and released on the target surface at a later time, simply by a slight wetting of the tattoo paper with water. This approach provides a quick and easy method of transferring OLEDs on virtually any surface. This is particularly appealing, in perspective, for on‐skin and disposable electronic applications. The proof of concept demonstrates, for the very first time, the feasibility of ultrathin operational OLED tattoos. While the performance of such devices is not yet comparable with that of OLEDs on rigid or flexible non‐tattooable substrates, the results show the potential for an OLED tattoo technology in integrated conformable electronic circuits
Expression of Microbial Enzymes in Mammalian Astrocytes to Modulate Lactate Release
Astrocytes support and modulate neuronal activity through the release of L-lactate. The
suggested roles of astrocytic lactate in the brain encompass an expanding range of vital functions,
including central control of respiration and cardiovascular performance, learning, memory, executive
behaviour and regulation of mood. Studying the effects of astrocytic lactate requires tools that limit
the release of lactate selectively from astrocytes. Here, we report the validation in vitro of novel
molecular constructs derived from enzymes originally found in bacteria, that when expressed in
astrocytes, interfere with lactate handling. When lactate 2-monooxygenase derived from M. smegmatis
was specifically expressed in astrocytes, it reduced intracellular lactate pools as well as lactate release
upon stimulation. D-lactate dehydrogenase derived from L. bulgaricus diverts pyruvate towards
D-lactate production and release by astrocytes, which may affect signalling properties of lactate in
the brain. Together with lactate oxidase, which we have previously described, this set of transgenic
tools can be employed to better understand astrocytic lactate release and its role in the regulation of
neuronal activity in different behavioural contexts
Weighted ergodic theorems for Banach-Kantorovich lattice
In the present paper we prove weighted ergodic theorems and multiparameter
weighted ergodic theorems for positive contractions acting on
. Our main tool is the use of methods of
measurable bundles of Banach-Kantorovich lattices.Comment: 11 page
The Impact of Psychological Flexibility on Psychological Well-Being in Adults With Obesity
Obesity is a global health problem that affects both physical and psychological health and well-being. Psychological flexibility is one of the key components related to psychological health. This cross-sectional study aims to investigate the impact of psychological flexibility on psychological well-being in a sample of 220 individuals with obesity. Multivariate analysis was performed to investigate the role of psychological flexibility in explaining psychological well-being, controlling for confounding factors (sex, age, and Body Mass Index). According to the results, psychological flexibility significantly explained psychological well-being. Our study provides additional evidence of the impact of psychological flexibility on psychological well-being. It also provides further support for the importance of integrating psychological flexibility in the psychological interventions for obesity
From Rotating Atomic Rings to Quantum Hall States
Considerable efforts are currently devoted to the preparation of ultracold
neutral atoms in the emblematic strongly correlated quantum Hall regime. The
routes followed so far essentially rely on thermodynamics, i.e. imposing the
proper Hamiltonian and cooling the system towards its ground state. In rapidly
rotating 2D harmonic traps the role of the transverse magnetic field is played
by the angular velocity. For particle numbers significantly larger than unity,
the required angular momentum is very large and it can be obtained only for
spinning frequencies extremely near to the deconfinement limit; consequently,
the required control on experimental parameters turns out to be far too
stringent. Here we propose to follow instead a dynamic path starting from the
gas confined in a rotating ring. The large moment of inertia of the fluid
facilitates the access to states with a large angular momentum, corresponding
to a giant vortex. The initial ring-shaped trapping potential is then
adiabatically transformed into a harmonic confinement, which brings the
interacting atomic gas in the desired quantum Hall regime. We provide clear
numerical evidence that for a relatively broad range of initial angular
frequencies, the giant vortex state is adiabatically connected to the bosonic
Laughlin state, and we discuss the scaling to many particles.Comment: 9 pages, 5 figure
Flavour physics constraints in the BMSSM
We study the implications of the presence of the two leading-order,
non-renormalizable operators in the Higgs sector of the MSSM to flavour physics
observables. We identify the constraints of flavour physics on the parameters
of the BMSSM when we: a) focus on a region of parameters for which electroweak
baryogenesis is feasible, b) use a CMSSM-like parametrization, and c) consider
the case of a generic NUHM-type model. We find significant differences as
compared to the standard MSSM case.Comment: 22 pages, 7 figure
Vanishing of phase coherence in underdoped Bi_2Sr_2CaCu_2O_8+d
Coherent time-domain spectroscopy is used to measure the screening and
dissipation of high-frequency electromagnetic fields in a set of underdoped
Bi_2Sr_2CaCu_2O_8+d thin films. The measurements provide direct evidence for a
phase-fluctuation driven transition from the superconductor to normal state,
with dynamics described well by the Berezinskii-Kosterlitz-Thouless theory of
vortex-pair unbinding.Comment: Nature, Vol. 398, 18 March 1999, pg. 221 4 pages with 4 included
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