8,440 research outputs found
Safety and effi cacy of insertion of supraglottic device in anaesthetised patients by fi rst-time users
Background: Over the years, several supraglottic devices have been developed, but the most recent one is the i-gel®. It is a new device with some distinctive features that set it apart from many of its competitors. This study was designed to determine the safety and efficacy of placing different airway devices by first-time users. Methods: Fifty volunteer doctors who are regularly involved in cardiopulmonary resuscitation and emergency medicine were divided into two groups on the basis of their experience and were timed to insert the two supraglottic devices, i-gel® and laryngeal mask airway (LMA), in ASA grade I, II and III anaesthetised patients under expert guidance. The haemodynamic parameters were recorded and the volunteers were asked to complete a questionnaire.Results: In both the groups, i-gel® was inserted in less time than LMA. The time taken for insertion of i-gel® by both the groups was not significant. The success rate of inserting i-gel® by both groups was not significant (p > 0.05). Ninety-six percent of participants in both the groups found that i-gel® was easier to insert and required minimal adjustment.Conclusion: Our results suggest that i-gel® is rapidly inserted by novices, and produces haemodynamic changes compared to those resulting from insertion of classic LMA. We suggest that the device is safe and can be used by first-time users and experts in cardiopulmonary resuscitation and in emergencies.Keywords: first-time users; laryngeal mask airway; i-ge
SMITIN: Self-Monitored Inference-Time INtervention for Generative Music Transformers
We introduce Self-Monitored Inference-Time INtervention (SMITIN), an approach
for controlling an autoregressive generative music transformer using classifier
probes. These simple logistic regression probes are trained on the output of
each attention head in the transformer using a small dataset of audio examples
both exhibiting and missing a specific musical trait (e.g., the
presence/absence of drums, or real/synthetic music). We then steer the
attention heads in the probe direction, ensuring the generative model output
captures the desired musical trait. Additionally, we monitor the probe output
to avoid adding an excessive amount of intervention into the autoregressive
generation, which could lead to temporally incoherent music. We validate our
results objectively and subjectively for both audio continuation and
text-to-music applications, demonstrating the ability to add controls to large
generative models for which retraining or even fine-tuning is impractical for
most musicians.
Audio samples of the proposed intervention approach are available on our demo
page http://tinyurl.com/smitin
Analyzing a higher order model and its implications in the late evolution of the Universe using recent observational datasets
In this research paper, we explore a well-motivated parametrization of the
time-dependent deceleration parameter, characterized by a cubic form, within
the context of late time cosmic acceleration. The current analysis is based on
the gravity theory, by considering the background metric as the
homogeneous and isotropic Friedmann Lema\^itre Robertson Walker (FLRW) metric.
Investigating the model reveals intriguing features of the late universe. To
constrain the model, we use the recent observational datasets, including cosmic
chronometer (CC), Supernovae (SNIa), Baryon Acoustic Oscillation (BAO), Cosmic
Microwave Background Radiation (CMB), Gamma Ray Burst (GRB), and Quasar (Q)
datasets. The joint analysis of these datasets results in tighter constraints
for the model parameters, enabling us to discuss both the physical and
geometrical aspects of the model. Moreover, we determine the present values of
the deceleration parameter (), the Hubble parameter (), and the
transition redshift () from deceleration to acceleration ensuring
consistency with some recent results of Planck 2018. Our statistical analysis
yields highly improved results, surpassing those obtained in previous
investigations. Overall, this study presents valuable insights into the higher
order model and its implications for late-time cosmic acceleration,
shedding light on the nature of the late universe
NeuroHeed+: Improving Neuro-steered Speaker Extraction with Joint Auditory Attention Detection
Neuro-steered speaker extraction aims to extract the listener's
brain-attended speech signal from a multi-talker speech signal, in which the
attention is derived from the cortical activity. This activity is usually
recorded using electroencephalography (EEG) devices. Though promising, current
methods often have a high speaker confusion error, where the interfering
speaker is extracted instead of the attended speaker, degrading the listening
experience. In this work, we aim to reduce the speaker confusion error in the
neuro-steered speaker extraction model through a jointly fine-tuned auxiliary
auditory attention detection model. The latter reinforces the consistency
between the extracted target speech signal and the EEG representation, and also
improves the EEG representation. Experimental results show that the proposed
network significantly outperforms the baseline in terms of speaker confusion
and overall signal quality in two-talker scenarios
Behaviour of three charged particles on a plane under perpendicular magnetic field
We consider the problem of three identical charged particles on a plane under
a perpendicular magnetic field and interacting through Coulomb repulsion. This
problem is treated within Taut's framework, in the limit of vanishing center of
mass vector , which corresponds to the strong magnetic
field limit, occuring for example in the Fractional Quantum Hall Effect. Using
the solutions of the biconfluent Heun equation, we compute the eigenstates and
show that there is two sets of solutions. The first one corresponds to a system
of three independent anyons which have their angular momenta fixed by the value
of the magnetic field and specified by a dimensionless parameter , the ratio of , the magnetic length, over , the Bohr
radius. This anyonic character, consistent with quantum mechanics of identical
particles in two dimensions, is induced by competing physical forces. The
second one corresponds to the case of the Landau problem when .
Finally we compare these states with the quantum Hall states and find that the
Laughlin wave functions are special cases of our solutions under certains
conditions.Comment: 15 pages, 3 figures, Accepeted in JP
Spinning, breathing, and flapping: Periodicities in Saturn’s middle magnetosphere
In Saturn’s magnetosphere, ubiquitous fluctuations with a period of ~10.7 h have been observed in Saturn kilometric radiation (SKR), auroral emissions, the magnetic field, the electron density, and energetic particle fluxes. Here we characterize previously unstudied periodicities in plasma properties inside of 15 RS near the equatorial plane. Although periodically varying magnetic perturbations rotate relatively smoothly (spinning), plasma properties do not. The phase of the peak value of plasma density or pressure perturbations can change substantially across a few hours of local time or RS. As a means of interpreting observations, we use a magnetohydrodynamic simulation that generates field‐aligned currents centered at 70° invariant latitude in Saturn’s southern ionosphere and rotating at the SKR period. The simulation reproduces many periodic features of the data including not only spinning perturbations but also global‐scale compression and expansion (breathing). Simulated plasma properties are also modulated by periodic large‐scale north‐south motion (flapping) in regions beyond ~15 Saturn radii (RS), which we do not analyze here. Inside of 15 RS, plasma responds to a superposition of spinning and breathing at the spin period, developing perturbations that peak at different phases depending on what is measured and where. Strong compressional effects act impulsively over a limited range of rotation phase. Superposition of local and global‐scale variations produces phase jumps across short distances and can introduce multiple peaks in the variation of plasma properties within one rotation period, accounting for anomalies in the phase dependence of periodic fluctuations identified in the sparse data available.Key PointsEquatorial plasma and field moments in the core region are modulated at the SKR periodThe peak phase of observed plasma properties depends on the location of measurementPeriodic changes in the magnetosphere can be described as spinning, breathing, and flappingPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136320/1/jgra53132-sup-0001-Text_SI-S01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136320/2/jgra53132_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136320/3/jgra53132-sup-0003-Figure_SI-S01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136320/4/jgra53132.pd
Conductivity in a symmetry broken phase: Spinless fermions with corrections
The dynamic conductivity of strongly correlated electrons in
a symmetry broken phase is investigated in the present work. The model
considered consists of spinless fermions with repulsive interaction on a simple
cubic lattice. The investigated symmetry broken phase is the charge density
wave (CDW) with wave vector which occurs at
half-filling. The calculations are based on the high dimensional approach, i.e.
an expansion in the inverse dimension is used. The finite dimensionality
is accounted for by the inclusion of linear terms in and the true finite
dimensional DOS. Special care is paid to the setup of a conserving
approximation in the sense of Baym/Kadanoff without inconsistencies. The
resulting Bethe-Salpeter equation is solved for the dynamic conductivity in the
non symmetry broken and in the symmetry broken phase (AB-CDW). The
dc-conductivity is reduced drastically in the CDW. Yet it does not vanish in
the limit due to a subtle cancellation of diverging mobility and
vanishing DOS. In the dynamic conductivity the energy gap
induced by the symmetry breaking is clearly discernible. In addition, the
vertex corrections of order lead to an excitonic resonance lying within
the gap.Comment: 23 pages, 19 figures included with psfig, Revtex; Physical Review
B15, in press (October/November 1996) depending on the printer/screen driver,
it might be necessary to comment out figures 3,4,5,10,11,12,19 and have them
printed separatel
Ionospheric flow shear associated with the preexisting auroral arc: A statistical study from the FAST spacecraft data
An auroral substorm is a disturbance in the magnetosphere that releases energy stored in the magnetotail into the high‐latitude ionosphere. By definition, an auroral substorm commences when a discrete auroral arc brightens and subsequently expands poleward and azimuthally. The arc that brightens is usually the most equatorward of several auroral arcs that remain quiescent for ~5 to ~60 min before the breakup commences. This arc is often referred to as the “preexisting auroral arc (PAA)” or the “growth‐phase arc.” In this study, we use FAST measurements to establish the statistics of flow patterns near PAAs in the ionosphere. We find that flow shear is present in the vicinity of a preexisting arc. When a PAA appears in the evening sector, enhanced westward flow develops equatorward of the arc, whereas when a PAA appears in the morning sector, enhanced eastward flow develops poleward of the arc. We benchmark locations of the PAAs relative to large‐scale field‐aligned currents (FACs) and convective flows in the ionosphere, finding that the arc forms in the upward current region within ~1° of the Region 1/Region 2 boundary in all local time sectors from 20 MLT to 03 MLT. We also find that near midnight in the Harang region, most of the PAAs lie within 0.5° poleward of the low‐latitude Region 1/Region 2 currents boundary and sit between the westward and eastward flow peak but equatorward of the flow reversal point. Finally, we examine arc‐associated electrodynamics and find that the FAC of the PAA is mainly closed by the north‐south Pedersen current in the ionosphere.Key PointsAn ionospheric flow shear is associated with the preexisting auroral arcThe FAC of the PAA is primarily closed by N‐S Pedersen current in the ionosphereThe PAA is located very close to the R1/R2 boundaryPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112278/1/jgra51768.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112278/2/jgra51768-sup-0001-supinfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112278/3/jgra51768-sup-0002-supinfo.pd
Scenario-Aware Audio-Visual TF-GridNet for Target Speech Extraction
Target speech extraction aims to extract, based on a given conditioning cue,
a target speech signal that is corrupted by interfering sources, such as noise
or competing speakers. Building upon the achievements of the state-of-the-art
(SOTA) time-frequency speaker separation model TF-GridNet, we propose
AV-GridNet, a visual-grounded variant that incorporates the face recording of a
target speaker as a conditioning factor during the extraction process.
Recognizing the inherent dissimilarities between speech and noise signals as
interfering sources, we also propose SAV-GridNet, a scenario-aware model that
identifies the type of interfering scenario first and then applies a dedicated
expert model trained specifically for that scenario. Our proposed model
achieves SOTA results on the second COG-MHEAR Audio-Visual Speech Enhancement
Challenge, outperforming other models by a significant margin, objectively and
in a listening test. We also perform an extensive analysis of the results under
the two scenarios.Comment: Accepted by ASRU 202
NIIRF: Neural IIR Filter Field for HRTF Upsampling and Personalization
Head-related transfer functions (HRTFs) are important for immersive audio,
and their spatial interpolation has been studied to upsample finite
measurements. Recently, neural fields (NFs) which map from sound source
direction to HRTF have gained attention. Existing NF-based methods focused on
estimating the magnitude of the HRTF from a given sound source direction, and
the magnitude is converted to a finite impulse response (FIR) filter. We
propose the neural infinite impulse response filter field (NIIRF) method that
instead estimates the coefficients of cascaded IIR filters. IIR filters mimic
the modal nature of HRTFs, thus needing fewer coefficients to approximate them
well compared to FIR filters. We find that our method can match the performance
of existing NF-based methods on multiple datasets, even outperforming them when
measurements are sparse. We also explore approaches to personalize the NF to a
subject and experimentally find low-rank adaptation to be effective.Comment: Accepted to ICASSP 202
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