101 research outputs found
Evaluating the uncertainty and reliability of standardized indices
Standardized indices are widely used in the spatio-temporal monitoring of several hydrological variables. The estimation of these indices is affected by uncertainty which depends on the methods adopted for their quantification and on the characteristics (i.e., size and variability) of the available sample of observations. In this paper various uncertainty measures, applicable to any kind of standardized index, are proposed. These measures derive from bootstrap-based confidence intervals expressed in years of return period and are effective for assessing both the uncertainty and the reliability of the index estimate. In the illustrative case study the indices considered are the Standardized Precipitation Index and the Standardized Precipitation Evapotranspiration Index. Their time series have been quantified by both nonparametric and parametric approaches, using the weather data of a single station in central Italy. For the parametric approach, two possible types of distributions have been assumed for each index. The results are discussed in order to analyze the behavior of the proposed uncertainty measures in relation to: sample size, type of approach (parametric or nonparametric), time scale, type of standardized index, and type of anomaly (excess or deficit)
Speaker anonymization using neural audio codec language models
The vast majority of approaches to speaker anonymization involve the
extraction of fundamental frequency estimates, linguistic features and a
speaker embedding which is perturbed to obfuscate the speaker identity before
an anonymized speech waveform is resynthesized using a vocoder. Recent work has
shown that x-vector transformations are difficult to control consistently:
other sources of speaker information contained within fundamental frequency and
linguistic features are re-entangled upon vocoding, meaning that anonymized
speech signals still contain speaker information. We propose an approach based
upon neural audio codecs (NACs), which are known to generate high-quality
synthetic speech when combined with language models. NACs use quantized codes,
which are known to effectively bottleneck speaker-related information: we
demonstrate the potential of speaker anonymization systems based on NAC
language modeling by applying the evaluation framework of the Voice Privacy
Challenge 2022.Comment: Submitted to ICASSP 202
Interaction and coherence of a plasmon-exciton polariton condensate
Polaritons are quasiparticles arising from the strong coupling of
electromagnetic waves in cavities and dipolar oscillations in a material
medium. In this framework, localized surface plasmon in metallic nanoparticles
defining optical nanocavities have attracted increasing interests in the last
decade. This interest results from their sub-diffraction mode volume, which
offers access to extremely high photonic densities by exploiting strong
scattering cross-sections. However, high absorption losses in metals have
hindered the observation of collective coherent phenomena, such as
condensation. In this work we demonstrate the formation of a non-equilibrium
room temperature plasmon-exciton-polariton condensate with a long range spatial
coherence, extending a hundred of microns, well over the excitation area, by
coupling Frenkel excitons in organic molecules to a multipolar mode in a
lattice of plasmonic nanoparticles. Time-resolved experiments evidence the
picosecond dynamics of the condensate and a sizeable blueshift, thus measuring
for the first time the effect of polariton interactions in plasmonic cavities.
Our results pave the way to the observation of room temperature superfluidity
and novel nonlinear phenomena in plasmonic systems, challenging the common
belief that absorption losses in metals prevent the realization of macroscopic
quantum states.Comment: 23 pages, 5 figures, SI 7 pages, 5 figure
Magnetic and Electric Mie-Exciton Polaritons in Silicon Nanodisks
Light-matter interactions at the nanoscale constitute a fundamental
ingredient for engineering applications in nanophotonics and quantum optics. To
this regard electromagnetic Mie resonances excited in high-refractive index
dielectric nanoparticles have recently attracted interest because of their
lower losses and better control over the scattering patterns compared to their
plasmonic metallic counterparts. The emergence of several resonances in those
systems results in an overall high complexity, where the electric and magnetic
dipoles have significant overlap in the case of spherical symmetry, thus
concealing the contributions of each resonance separately. Here we show,
experimentally and theoretically, the emergence of strong light-matter coupling
between the magnetic and electric-dipole resonances of individual silicon
nanodisks coupled to a J-aggregated organic semiconductor resonating at optical
frequencies, evidencing how the different properties of the two resonances
results in two different coupling strengths. The energy splittings observed are
of the same order of magnitude as in similar plasmonic systems, thus confirming
dielectric nanoparticles as promising alternatives for localized strong
coupling studies. The coupling of both the electric and magnetic dipole
resonances can offer interesting possibilities for the control of directional
light scattering in the strong-coupling regime and the dynamic tuning of
nanoscale light-matter coupled states by external fields
Gain-compensated cavities for the dynamic control of light-matter interactions
We propose an efficient approach for actively controlling the Rabi
oscillations in emitter-cavity hybrids based on the presence of an element with
optical gain. Inspired by recent developments in parity-time
()-symmetry photonics, we show that nano- or micro-cavities where
intrinsic losses are partially or fully compensated by an externally
controllable amount of gain offer unique capabilities for manipulating the
dynamics of emitters. In particular, one can drastically modify the dynamics of
the system, increase the overall occupation numbers, enhance the longevity of
the Rabi oscillations, and even decelerate them to the point where their
experimental observation becomes less challenging. Furthermore, we show that
there is a specific gain value that leads to an exceptional point, where both
emitter and cavity occupation oscillate practically in phase, with occupation
numbers that can significantly exceed unity. By revisiting a
recently-introduced Rabi-visibility measure, we provide robust guidelines for
quantifying the coupling strength and achieving strong-coupling with adaptable
Rabi frequency via loss compensation
CORRIGENDUM to The mechanisms of acute interstitial nephritis in the era of immune checkpoint inhibitors in melanoma
In this article, the authors’ first names and surnames were incorrectly listed in the wrong order. The correct author list is: Marco Tucci, Anna Passarelli, Annalisa Todisco, Francesco Mannavola, Luigia Stefania Stucci, Stella D’Oronzo, Michele Rossini, Marco Taurisano, Loreto Gesualdo and Franco Silvestris
Immunometabolism Modulation by Extracts from Pistachio Stalks Formulated in Phospholipid Vesicles
Several studies have demonstrated the effectiveness of plant extracts against various
diseases, especially skin disorders; namely, they exhibit overall protective effects. The Pistachio
(Pistacia vera L.) is known for having bioactive compounds that can effectively contribute to a person’s
healthy status. However, these benefits may be limited by the toxicity and low bioavailability
often inherent in bioactive compounds. To overcome these problems, delivery systems, such as
phospholipid vesicles, can be employed. In this study, an essential oil and a hydrolate were produced
from P. vera stalks, which are usually discarded as waste. The extracts were characterized by liquid
and gas chromatography coupled with mass spectrometry and formulated in phospholipid vesicles
intended for skin application. Liposomes and transfersomes showed small size (<100 nm), negative
charge (approximately −15 mV), and a longer storage stability for the latter. The entrapment efficiency
was determined via the quantification of the major compounds identified in the extracts and was
>80%. The immune-modulating activity of the extracts was assayed in macrophage cell cultures. Most
interestingly, the formulation in transfersomes abolished the cytotoxicity of the essential oil while
increasing its ability to inhibit inflammatory mediators via the immunometabolic citrate pathway
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