Tripartite entanglement in quantum memristors

We study the entanglement and memristive properties of three coupled quantum memristors. We consider quantum memristors based on superconducting asymmetric SQUID architectures which are coupled via inductors. The three quantum memristors are arranged in two different geometries: linear and triangular coupling configurations. We obtain a variety of correlation measures, including bipartite entanglement and tripartite negativity. We find that, for identical quantum memristors, entanglement and memristivity follow the same behavior for the triangular case and the opposite one in the linear case. Finally, we study the multipartite correlations with the tripartite negativity and entanglement monogamy relations, showing that our system has genuine tripartite entanglement. Our results show that quantum correlations in multipartite memristive systems have a non-trivial role and can be used to design quantum memristor arrays for quantum neural networks and neuromorphic quantum computing architectures.Comment: 9 pages, 6 figure

Axonal degeneration induced by glutamate-excitotoxicity is mediated by necroptosis

Neuronal excitotoxicity induced by glutamate leads to cell death and functional impairment in a variety of central nervous system pathologies. Glutamate-mediated excitotoxicity triggers neuronal apoptosis in the cell soma as well as degeneration of axons and dendrites by a process associated to calcium increase and mitochondrial dysfunction. Importantly, degeneration of axons initiated by diverse stimuli, including excitotoxicity, has been proposed as an important pathological event leading to functional impairment in neurodegenerative conditions. Here we demonstrate that excitotoxicity-induced axonal degeneration proceeds by a mechanism dependent on the necroptotic kinases RIPK1, RIPK3 and the necroptotic mediator MLKL. Inhibition of RIPK1, RIPK3 or MLKL prevent key steps in the axonal degeneration cascade including mitochondrial depolarization, the opening of the permeability transition pore and calcium dysregulation in the axon. Interestingly, the same excitotoxic stimuli lead to apoptosis in the cell soma, demonstrating the co-activation of two independent degenerative mechanisms in different compartments of the same cell. The identification of necroptosis as a key mechanism of axonal degeneration after excitotoxicity is an important initial step to develop novel therapeutic strategies for nervous system disorders

Torrefacción de biomasa en un reactor de tornillo a escala de banco: efecto de la temperatura y del tipo de biomasa

The intensive use of fossil fuels contributes significantly to global warming and the growing world energy crisis. Thus, it is necessary to develop alternative energy sources that make the energy matrix more flexible and reduce environmental impacts. An outstanding option is the conversion of residual biomass into energy because it produces a low-emission fuel in terms of CO2. Therefore, this study aimed to improve the physicochemical properties of two residual biomasses (i.e., pine sawdust and spent coffee ground, SCG) through a torrefaction process. Biomass valorization was carried out in a bench-scale screw reactor (2.8 kg/h). The effect of temperature was evaluated between 200 °C and 300 °C, and the torrefied biomasses were characterized by instrumental techniques: calorific value, infrared spectroscopy analysis, thermogravimetric analysis, and scanning electron microscopy. Both biomasses exhibited an increase in calorific value when the process temperature was raised. This behavior is associated with the thermal degradation of the hemicellulose fraction and the increase in fixed carbon. In addition, the infrared analysis showed a decrease in OH and H-O-H signals associated with polar functional groups. These results show the high potential of the valorization of these two biomasses thanks to the decrease in polar groups, which have a great affinity with water, and the obtaining of calorific values close to those of fossil fuels such as lignite or sub-bituminous coal.El uso intensivo de combustibles fósiles contribuye significativamente al calentamiento global y a la creciente crisis energética mundial, en consecuencia, es necesario el desarrollo de fuentes de energía alternativas que permitan flexibilizar la matriz energética y mitigar los impactos ambientales. Una opción destacada es la conversión de biomasa residual a energía, pues la biomasa constituye un combustible con impacto menor respecto a las emisiones de CO2. Por consiguiente, este estudio tuvo como objetivo promover las propiedades fisicoquímicas de dos biomasas residuales, el aserrín de pino y la borra de café, mediante el proceso de torrefacción. La valorización energética de las biomasas se realizó en un reactor de tornillo a escala de banco (2.8 kg/h). Se evaluó el efecto de la temperatura en el rango entre 200 °C y 300 °C y se caracterizaron las biomasas torrefactadas mediante técnicas instrumentales: poder calorífico, análisis próximo, análisis infrarrojo y microscopía electrónica de barrido. Para ambas biomasas, al aumentar la temperatura de proceso se obtuvo un incremento del poder calorífico. Este comportamiento se asocia a la degradación térmica de la fracción de hemicelulosa, así como al incremento del carbono fijo. Además, en los análisis infrarrojos se observó una disminución de las señales OH y H-O-H asociadas a grupos funcionales polares. Los resultados anteriores muestran el alto potencial de valorización de las biomasas de estudio, respecto a la disminución de grupos polares que tienen gran afinidad por el agua, así como la obtención de poderes caloríficos cercanos a un combustible tipo carbón lignito o subbituminoso

Helmholtz theorem and the v-gauge in the problem of superluminal and instantaneous signals in classical electrodynamics

In this work we substantiate the applying of the Helmholtz vector decomposition theorem (H-theorem) to vector fields in classical electrodynamics. Using the H-theorem, within the framework of the two-parameter Lorentz-like gauge (so called v-gauge), we show that two kinds of magnetic vector potentials exist: one of them (solenoidal) can act exclusively with the velocity of light c and the other one (irrotational) with an arbitrary finite velocity $v$ (including a velocity more than c . We show also that the irrotational component of the electric field has a physical meaning and can propagate exclusively instantaneously.Comment: This variant has been accepted for publication in Found. Phys. Letter

Lasing in Two-Dimensional Tin Perovskites

Two-dimensional (2D) perovskites have been proposed as materials capable of improving the stability and surpassing the radiative recombination efficiency of three-dimensional perovskites. However, their luminescent properties have often fallen short of what has been expected. In fact, despite attracting considerable attention for photonic applications during the last two decades, lasing in 2D perovskites remains unclear and under debate. Here, we were able to improve the optical gain properties of 2D perovskite and achieve optically pumped lasing. We show that the choice of the spacer cation affects the defectivity and photostability of the perovskite, which in turn influences its optical gain. Based on our synthetic strategy, we obtain PEA2SnI4 films with high crystallinity and favorable optical properties, resulting in amplified spontaneous emission (ASE) with a low threshold (30 μJ/cm2), a high optical gain above 4000 cm-1 at 77 K, and ASE operation up to room temperature

Ab-initio calculation of the electronic and optical excitations in polythiophene: effects of intra- and interchain screening

We present an calculation of the electronic and optical excitations of an isolated polythiophene chain as well as of bulk polythiophene. We use the GW approximation for the electronic self-energy and include excitonic effects by solving the electron-hole Bethe-Salpeter equation. The inclusion of interchain screening in the case of bulk polythiophene drastically reduces both the quasi-particle band gap and the exciton binding energies, but the optical gap is hardly affected. This finding is relevant for conjugated polymers in general.Comment: 4 pages, 1 figur

IRAS4A1: Multi-wavelength continuum analysis of a very flared Class 0 disk

Understanding the formation of substructures in protoplanetary disks is vital for gaining insights into dust growth and the process of planet formation. Studying these substructures in highly embedded Class 0 objects using the Atacama Large Millimeter/submillimeter Array (ALMA), however, poses significant challenges. Nonetheless, it is imperative to do so to unravel the mechanisms and timing behind the formation of these substructures. In this study, we present high-resolution ALMA data at Bands 6 and 4 of the NGC1333 IRAS4A Class 0 protobinary system. This system consists of two components, A1 and A2, separated by 1.8" and located in the Perseus molecular cloud at $\sim$293 pc distance. To gain a comprehensive understanding of the dust properties and formation of substructures in the early stages, we conducted a multi-wavelength analysis of IRAS4A1. Additionally, we sought to address whether the lack of observed substructures in very young disks, could be attributed to factors such as high degrees of disk flaring and large scale heights. To explore this phenomenon, we employed radiative transfer models using RADMC-3D. Our multi-wavelength analysis of A1 discovered characteristics such as high dust surface density, substantial dust mass within the disk, and elevated dust temperatures. These findings suggest the presence of large dust grains compared to the ones in the interstellar medium (ISM), greater than 100 microns in size within the region. Furthermore, while there's no direct detection of any substructure, our models indicate that some, such as a small gap, must be present. In summary, this result implies that disk substructures may be masked or obscured by a large scale height in combination with a high degree of flaring in Class 0 disks. [Abridged]Comment: Accepted for publication in A&A, 13 pages, 7 figure

Prepartum body condition score changes and the secretion of acute phase proteins in dairy cows.

O objetivo deste estudo foi investigar o efeito da condição corporal (BCS) durante o período de pré-parto, sobre a concentração de proteínas de fase aguda e parâmetros metabólicos em vacas leiteiras