855 research outputs found
Corruption Perceptions: the Trap of Democratization, a Panel Data Analysis
Lâindice de perception de la corruption de Transparency International (TI) est le plus cĂ©lĂšbre des indicateurs de corruption depuis sa premiĂšre publication, en 1995. Cet indicateur est Ă©galement considĂ©rĂ© comme la plus robuste des mesures de ce flĂ©au. Cependant, puisque il sâagit prĂ©cisĂ©ment dâun indicateur basĂ© sur des perceptions, il connait certaines limites. Bien que Transparency International appelle inlassablement Ă une utilisation plus prudente de ses indicateurs, les dĂ©cideurs continuent de lui prĂȘter un rĂŽle dâoutil dâaide Ă la prise de dĂ©cision. Nous avions isolĂ©, dans un article prĂ©cĂ©dent, le rĂŽle jouĂ© par les mĂ©dias dans les perceptions de la corruption. Nous avions suggĂ©rĂ© que les jeunes dĂ©mocraties puissent ĂȘtre pĂ©nalisĂ©es par lâindicateur phare de Transparency International. En effet, nous avions montrĂ© que lâouverture des mĂ©dias conduisait Ă une meilleure couverture des actes de corruption, entrainant avec elle une plus forte perception de la corruption dĂ©jĂ existante, mais non rĂ©vĂ©lĂ©e. Notre article prĂ©cĂ©dent utilisait des donnĂ©es en coupe transversale. Dans un souci dâamĂ©lioration de la robustesse et de la prĂ©cision de lâanalyse prĂ©cĂ©demment menĂ©e, nous avons collectĂ© des sĂ©ries temporelles afin dâentreprendre une analyse en donnĂ©es de panel. Dans ce nouvel article, nous analysons le lien entre dĂ©mocratie et perceptions de la corruption Ă la lueur dâun possible biais dâouverture des rĂ©gimes en place, biais que nous avions qualifiĂ© de « rĂ©flectif ». The Corruption Perception Index (CPI) is the most famous corruption evaluation since its first publication by Transparency International (TI), in 1995. This index is also considered the most robust measure of corruption perceptions. However, since it precisely refers to perceptions, it inevitably faces some limitations. Although Transparency International continuously advocates for a better use of its indexes, policy makers keep using the CPI as a decision making tool. In a previous article we isolated the role played by the media in corruption perceptions. We previously suggested that young democracies were penalized by Transparency International. Indeed, we showed that media aperture leads to a better coverage of corruption deeds and therefore drives a stronger perception of already existing - but not yet broadcasted - corruption. Our previous paper was using cross-section data. Pursuing more consistent evidence and robustness improvement, we collected time series to perform a panel data analysis, questioning the stability and precision of our earlier findings. In this new paper, we investigate the link between democracy and corruption perceptions, in the light of a possible opening bias, we already called âreflective biasâ. (Full text in french)
A psychoacoustic "NofM"-type speech coding strategy for cochlear implants
We describe a new signal processing technique for cochlear implants using a psychoacoustic-masking model. The technique is based on the principle of a so-called "NofM" strategy. These strategies stimulate fewer channels (N) per cycle than active electrodes (NofM; N < M). In "NofM" strategies such as ACE or SPEAK, only the N channels with higher amplitudes are stimulated. The new strategy is based on the ACE strategy but uses a psychoacoustic-masking model in order to determine the essential components of any given audio signal. This new strategy was tested on device users in an acute Study, with either 4 or 8 channels stimulated per cycle. For the first condition (4 channels), the mean improvement over the ACE strategy was 17%. For the second condition (8 channels), no significant difference was found between the two strategies
ViSE: Vision-Based 3D Online Shape Estimation of Continuously Deformable Robots
The precise control of soft and continuum robots requires knowledge of their
shape. The shape of these robots has, in contrast to classical rigid robots,
infinite degrees of freedom. To partially reconstruct the shape, proprioceptive
techniques use built-in sensors resulting in inaccurate results and increased
fabrication complexity. Exteroceptive methods so far rely on placing reflective
markers on all tracked components and triangulating their position using
multiple motion-tracking cameras. Tracking systems are expensive and infeasible
for deformable robots interacting with the environment due to marker occlusion
and damage. Here, we present a regression approach for 3D shape estimation
using a convolutional neural network. The proposed approach takes advantage of
data-driven supervised learning and is capable of real-time marker-less shape
estimation during inference. Two images of a robotic system are taken
simultaneously at 25 Hz from two different perspectives, and are fed to the
network, which returns for each pair the parameterized shape. The proposed
approach outperforms marker-less state-of-the-art methods by a maximum of 4.4%
in estimation accuracy while at the same time being more robust and requiring
no prior knowledge of the shape. The approach can be easily implemented due to
only requiring two color cameras without depth and not needing an explicit
calibration of the extrinsic parameters. Evaluations on two types of soft
robotic arms and a soft robotic fish demonstrate our method's accuracy and
versatility on highly deformable systems in real-time. The robust performance
of the approach against different scene modifications (camera alignment and
brightness) suggests its generalizability to a wider range of experimental
setups, which will benefit downstream tasks such as robotic grasping and
manipulation
Role of alkali cations for the excited state dynamics of liquid water near the surface
Time-resolved liquid jet photoelectron spectroscopy was used to explore the excited state dynamics at the liquid water surface in the presence of alkali cations. The data were evaluated with the help of ab initio calculations on alkali-water clusters and an extension of these results on the basis of the dielectric continuum model: 160nm, sub-20fs vacuum ultraviolet pulses excite water molecules in the solvent shell of Na + or K + cations and evolve into a transient hydrated complex of alkali-ion and electron. The vertical ionization energy of this transient is about 2.5eV, significantly smaller than that of the solvated electron. ??? 2012 American Institute of Physics.open1
Low Voltage Electrohydraulic Actuators for Untethered Robotics
Rigid robots can be precise in repetitive tasks but struggle in unstructured
environments. Nature's versatility in such environments inspires researchers to
develop biomimetic robots that incorporate compliant and contracting artificial
muscles. Among the recently proposed artificial muscle technologies,
electrohydraulic actuators are promising since they offer comparable
performance to mammalian muscles in terms of speed and power density. However,
they require high driving voltages and have safety concerns due to exposed
electrodes. These high voltages lead to either bulky or inefficient driving
electronics that make untethered, high-degree-of-freedom bio-inspired robots
difficult to realize. Here, we present low voltage electrohydraulic actuators
(LEAs) that match mammalian skeletal muscles in average power density (50.5
W/kg) and peak strain rate (971 percent/s) at a driving voltage of just 1100 V.
This driving voltage is approx. 5 - 7 times lower compared to other
electrohydraulic actuators using paraelectric dielectrics. Furthermore, LEAs
are safe to touch, waterproof, and self-clearing, which makes them easy to
implement in wearables and robotics. We characterize, model, and physically
validate key performance metrics of the actuator and compare its performance to
state-of-the-art electrohydraulic designs. Finally, we demonstrate the utility
of our actuators on two muscle-based electrohydraulic robots: an untethered
soft robotic swimmer and a robotic gripper. We foresee that LEAs can become a
key building block for future highly-biomimetic untethered robots and wearables
with many independent artificial muscles such as biomimetic hands, faces, or
exoskeletons.Comment: Stephan-Daniel Gravert and Elia Varini contributed equally to this
wor
Virtuelles Pubquiz: (k)ein Kahoot! mit Mehrwert
In diesem Beitrag wird vor dem Hintergrund der aktuellen Situation der Fernlehre an Hochschulen das virtuelle Pubquiz als methodisch-didaktisches Format vorgestellt, das sich von traditionellen Quiz-Formaten vom Typ Kahoot! durch Konzeption und Design unterscheidet.Against the background of the current situation of distance learning at universities, this article presents the virtual pub quiz as a methodological-didactic format that differs from traditional quiz formats of the Kahoot! type in conception and design
Photosensitiser functionalised luminescent upconverting nanoparticles for efficient photodynamic therapy of breast cancer cells
Photodynamic therapy (PDT) is a well-established treatment of cancer in which cell toxic reactive oxygen species, including singlet oxygen (1O2), are produced by a photosensitiser drug following irradiation of a specific wavelength. Visible light is commonly used as the excitation source in PDT, although these wavelengths do have limited tissue penetration. In this research, upconverting nanoparticles (UCNPs) functionalised with the photosensitiser Rose Bengal (RB) have been designed and synthesised for PDT of breast cancer cells. The use of UCNPs shifts the required excitation wavelength for the production of 1O2 to near infrared light (NIR) thus allowing deeper tissue penetration. The system was designed to maximise the production of 1O2via efficient Förster resonance energy transfer (FRET) from the UCNPs to the photosensitiser. Highly luminescent NaYF4:Yb,Er,Gd@NaYF4 coreâshell UCNPs were synthesised that exhibited two main anti-Stokes emission bands at 541 and 652 nm following 980 nm irradiation. RB was chosen as the photosensitiser since its absorption band overlaps with the green emission of the UCNPs. To achieve efficient energy transfer from the nanoparticles to the photosensitiser, the functionalised UCNPs included a short L-lysine linker to attach the RB to the nanocore yielding RB-lysine functionalised UCNPs. The efficient FRET from the UCNPs to the RB was confirmed by luminescence lifetime measurements. The light emitted by the UCNPs at 541 nm, following excitation at 980 nm, generates the 1O2via the RB. Multi-photon and confocal laser scanning microscopies confirmed the internalisation of the RB-lysine-UCNPs by SK-BR-3 breast cancer cells. Cell viability studies revealed that the RB-lysine-UCNPs induced low dark toxicity in cells prior to PDT treatment. Importantly, following irradiation at 980 nm, high levels of cell death were observed in cells loaded with the RB-lysine-UCNPs. Cell death following PDT treatment was also confirmed using propidium iodide and confocal microscopy. The high drug loading capacity (160 RB/nanoparticle) of the UCNPs, the efficient FRET from the UCNPs to the photosensitiser, the high level of accumulation inside the cells and their PDT cell kill suggest that the RB-lysine-UCNPs are promising for NIR PDT and hence suitable for the treatment of deep-lying cancer tumours
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