An Algorithm for Choosing the Optimal Number of Muscle Synergies during Walking

In motor control studies, the 90% thresholding of variance accounted for (VAF) is the classical way of selecting the number of muscle synergies expressed during a motor task. However, the adoption of an arbitrary cut-off has evident drawbacks. The aim of this work is to describe and validate an algorithm for choosing the optimal number of muscle synergies (ChoOSyn), which can overcome the limitations of VAF-based methods. The proposed algorithm is built considering the following principles: (1) muscle synergies should be highly consistent during the various motor task epochs (i.e., remaining stable in time), (2) muscle synergies should constitute a base with low intra-level similarity (i.e., to obtain information-rich synergies, avoiding redundancy). The algorithm performances were evaluated against traditional approaches (threshold-VAF at 90% and 95%, elbow-VAF and plateau-VAF), using both a simulated dataset and a real dataset of 20 subjects. The performance evaluation was carried out by analyzing muscle synergies extracted from surface electromyographic (sEMG) signals collected during walking tasks lasting 5 min. On the simulated dataset, ChoOSyn showed comparable performances compared to VAF-based methods, while, in the real dataset, it clearly outperformed the other methods, in terms of the fraction of correct classifications, mean error (ME), and root mean square error (RMSE). The proposed approach may be beneficial to standardize the selection of the number of muscle synergies between different research laboratories, independent of arbitrary thresholds

Numerical model of an Yb:Er:Tm:Ho co-doped germanate glass: concentrations optimization and transfer function

In this paper, we numerically simulate the population of levels of an Yb:Er:Tm:Ho co-doped germanate glass pumped at 980 nm, that could be able to generate broad emission in a wavelength range from 1500 nm to 2100 nm. The aim of this work is to study the possibility of reaching a homogeneous inversion of Er, Tm and Ho, in order to further develop ultra-broadband active devices. We study the influence of a variation in the concentration of the dopants in such a complex system, which exhibits many energy transfer phenomena between different rare earth ions. Furthermore, we computed the transfer function of the system to evaluate the pump noise influence

Conformal-invariance of 2D quantum turbulence in an exciton-polariton fluid of light

The similarities of quantum turbulence with classical hydrodynamics allow quantum fluids to provide essential models of their classical analogue, paving the way for fundamental advances in physics and technology. Recently, experiments on 2D quantum turbulence observed the clustering of same-sign vortices in strong analogy with the inverse energy cascade of classical fluids. However, self-similarity of the turbulent flow, a fundamental concept in the study of classical turbulence, has so far remained largely unexplored in quantum systems. Here, thanks to the unique features of exciton-polaritons, we measure the scale invariance of velocity circulations and show that the cascade process follows the universal scaling of critical phenomena in 2D. We demonstrate this behaviour from the statistical analysis of the experimentally measured incompressible velocity field and the microscopic imaging of the quantum fluid. These results can find wide application in both quantum and classical 2D turbulence

Dynamics of a vortex lattice in a non-equilibrium polariton superfluid

If a quantum fluid is put in motion with enough angular momentum, at equilibrium the ground state of the system is given by an array of quantised vortices. In a driven-dissipative polariton fluid, we demonstrate that the reverse process is also possible. Upon initially imprinting a static and regular vortex array, the quantum fluid starts rotating. By tracking on picosecond time scales many quantized vortices, we present the first measure of rigid-body rotation in a polariton condensate. Such many-body motion agrees with the Feynman quantization of superfluid velocity, which we show to be valid even if our system is expanding and equilibrium is never attained

An Algorithm for Choosing the Optimal Number of Muscle Synergies during Walking

In motor control studies, the 90% thresholding of variance accounted for (VAF) is the classical way of selecting the number of muscle synergies expressed during a motor task. However, the adoption of an arbitrary cut-off has evident drawbacks. The aim of this work is to describe and validate an algorithm for choosing the optimal number of muscle synergies (ChoOSyn), which can overcome the limitations of VAF-based methods. The proposed algorithm is built considering the following principles: (1) muscle synergies should be highly consistent during the various motor task epochs (i.e., remaining stable in time), (2) muscle synergies should constitute a base with low intra-level similarity (i.e., to obtain information-rich synergies, avoiding redundancy). The algorithm performances were evaluated against traditional approaches (threshold-VAF at 90% and 95%, elbow-VAF and plateau-VAF), using both a simulated dataset and a real dataset of 20 subjects. The performance evaluation was carried out by analyzing muscle synergies extracted from surface electromyographic (sEMG) signals collected during walking tasks lasting 5 min. On the simulated dataset, ChoOSyn showed comparable performances compared to VAF-based methods, while, in the real dataset, it clearly outperformed the other methods, in terms of the fraction of correct classifications, mean error (ME), and root mean square error (RMSE). The proposed approach may be beneficial to standardize the selection of the number of muscle synergies between different research laboratories, independent of arbitrary thresholds.</jats:p

Exciton-polariton ring Josephson junction

Abstract Macroscopic coherence in quantum fluids allows the observation of interference effects in their wavefunctions, and enables applications such as superconducting quantum interference devices based on Josephson tunneling. The Josephson effect manifests in both fermionic and bosonic systems, and has been well studied in superfluid helium and atomic Bose-Einstein condensates. In exciton-polariton condensates—that offer a path to integrated semiconductor platforms—creating weak links in ring geometries has so far remained challenging. In this work, we realize a Josephson junction in a polariton ring condensate. Using optical control of the barrier, we induce net circulation around the ring and demonstrate both superfluid-hydrodynamic and the Josephson regime characterized by a sinusoidal tunneling current. Our theory in terms of the free-energy landscapes explains the appearance of these regimes using experimental values. These results show that weak links in ring condensates can be explored in optical integrated circuits and hold potential for room-temperature applications

Hyperthermic Intraperitoneal Chemotherapy for Primary or Recurrent Adrenocortical Carcinoma. A Single Center Study.

BACKGROUND: This study explores the impact of Hypertermic Intra PEritoneal Chemotherapy (HIPEC) on adrenocortical carcinoma (ACC) management through a safety analysis completed by a preliminary evaluation of survival performances. METHODS: Retrospective chart review of 27 patients submitted to surgical treatment completed by HIPEC for primary (SP, 13 patients) or recurrent (SR, 14 patients, 17 treatments) ACC. Safety was evaluated by means of procedural morbidity and mortality. Survival performances included multiple end points: local/peritoneal disease-free survival (l/pDFS), overall progression-free survival (OPFS), and overall survival (OS). RESULTS: In the SP group, mortality was nil and morbidity was 46% (major 23%). At a median follow-up of 25 months, the median value for all the different survival measures had not been reached. Mortality was also nil in the SR group. However, morbidity was 77% (major 18%). Median l/pDFS and OPFS were 12 ± 4 and 8 ± 2 months, respectively. At a median follow-up of 30 months, median OS had not been reached. CONCLUSION: Surgery and HIPEC is an invasive procedure. Its employment in the surgery for primary setting deserves attention as it may affect oncologic outcomes positively. Its value in the management of recurrences seems less appreciable, albeit it may find its place in the multimodal management of a rare disease for which multiple therapeutic options do not yet exist

Hyperthermic Intraperitoneal Chemotherapy for Primary or Recurrent Adrenocortical Carcinoma. A Single Center Study

Background. This study explores the impact of Hypertermic Intra PEritoneal Chemotherapy (HIPEC) on adrenocortical carcinoma (ACC) management through a safety analysis completed by a preliminary evaluation of survival performances. Methods. Retrospective chart review of 27 patients submitted to surgical treatment completed by HIPEC for primary (SP, 13 patients) or recurrent (SR, 14 patients, 17 treatments) ACC. Safety was evaluated by means of procedural morbidity and mortality. Survival performances included multiple end points: local/peritoneal disease-free survival (l/pDFS), overall progression-free survival (OPFS), and overall survival (OS). Results. In the SP group, mortality was nil and morbidity was 46% (major 23%). At a median follow-up of 25 months, the median value for all the different survival measures had not been reached. Mortality was also nil in the SR group. However, morbidity was 77% (major 18%). Median l/pDFS and OPFS were 12 ± 4 and 8 ± 2 months, respectively. At a median follow-up of 30 months, median OS had not been reached. Conclusion. Surgery and HIPEC is an invasive procedure. Its employment in the surgery for primary setting deserves attention as it may affect oncologic outcomes positively. Its value in the management of recurrences seems less appreciable, albeit it may find its place in the multimodal management of a rare disease for which multiple therapeutic options do not yet exist.</jats:p