Analog simulator of integro-differential equations with classical memristors.

An analog computer makes use of continuously changeable quantities of a system, such as its electrical, mechanical, or hydraulic properties, to solve a given problem. While these devices are usually computationally more powerful than their digital counterparts, they suffer from analog noise which does not allow for error control. We will focus on analog computers based on active electrical networks comprised of resistors, capacitors, and operational amplifiers which are capable of simulating any linear ordinary differential equation. However, the class of nonlinear dynamics they can solve is limited. In this work, by adding memristors to the electrical network, we show that the analog computer can simulate a large variety of linear and nonlinear integro-differential equations by carefully choosing the conductance and the dynamics of the memristor state variable. We study the performance of these analog computers by simulating integro-differential models related to fluid dynamics, nonlinear Volterra equations for population growth, and quantum models describing non-Markovian memory effects, among others. Finally, we perform stability tests by considering imperfect analog components, obtaining robust solutions with up to 13% relative error for relevant timescales.

Multiqubit and multilevel quantum reinforcement learning with quantum technologies.

We propose a protocol to perform quantum reinforcement learning with quantum technologies. At variance with recent results on quantum reinforcement learning with superconducting circuits, in our current protocol coherent feedback during the learning process is not required, enabling its implementation in a wide variety of quantum systems. We consider diverse possible scenarios for an agent, an environment, and a register that connects them, involving multiqubit and multilevel systems, as well as open-system dynamics. We finally propose possible implementations of this protocol in trapped ions and superconducting circuits. The field of quantum reinforcement learning with quantum technologies will enable enhanced quantum control, as well as more efficient machine learning calculations.

¿Retinopexia neumática o implante de silicona para pacientes con desprendimiento regmatógeno de retina? / Scleral buckle versus pneumatic retinopexy for rhegmatogenous retinal detachments

Resumen INTRODUCCIÓN: l desprendimiento de retina de tipo regmatógeno es aquel causado por un desgarro o ruptura de la retina, y es causa frecuente de pérdida de visión. Dentro del manejo quirúrgico existen varias opciones, entre ellas el implante de silicona o cirugía convencional y la retinopexia neumática. A pesar de que la mayoría de los profesionales prefiere el uso de implante de silicona, la retinopexia neumática es un procedimiento más simple, de menor costo y sigue siendo considerada como alternativa en algunos casos de desprendimiento de retina regmatógeno, sin embargo hay poca evidencia que compare ambas intervenciones. MÉTODOS: Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos tres revisiones sistemáticas que en conjunto incluyeron seis estudios primarios, de los cuales tres corresponden a ensayos aleatorizados. Concluimos que el resultado anatómico podría ser mejor con el uso de implante de silicona en términos de re-aplicación de la retina y del riesgo de recurrencia del desprendimiento, pero la retinopexia neumática podría disminuir la incidencia de efectos adversos quirúrgicos oculares.

Abstract INTRODUCTION: Rhegmatogenous retinal detachment is caused by a tear in the retina and is a frequent cause of vision loss. Its treatment is mainly surgical and the following alternatives can be identified: scleral buckling or classic surgery, pneumatic retinopexy and vitrectomy. Between the first two options, most professionals prefer scleral buckling over pneumatic retinopexy, but the latter is a simpler, cheaper and lower-risk procedure, so it is still considered as an option for selected patients. However, there is little evidence comparing both interventions. METHODS: To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS We identified three systematic reviews including six studies overall, of which three were randomized trials. We concluded the anatomic result might be better with scleral buckling in terms of retinal reattachment and risk of recurrence, but the risk of ocular adverse events might be lower with pneumatic retinopexy.

Natamicina versus voriconazol para queratitis fúngica / Natamycin versus voriconazole for fungal keratitis

INTRODUCCIÓN: La queratitis infecciosa de origen fúngico afecta principalmente a personas de países tropicales y subtropicales, y constituye una importante causa de ceguera prevenible. Los antifúngicos tópicos, en particular la natamicina y el voriconazol, se consideran efectivos, pero no está claro cuál de ellos constituye la mejor alternativa de tratamiento. MÉTODOS: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos tres revisiones sistemáticas que en conjunto incluyeron tres estudios primarios, todos correspondientes a ensayos aleatorizados. Concluimos que natamicina probablemente se asocia a mejor agudeza visual tras la infección, y que previene la perforación corneal y/o la necesidad de realizar queratoplastia terapéutica en comparación a voriconazol en queratitis fúngica.

INTRODUCTION: Infectious keratitis of fungal origin mainly affects people in tropical and subtropical countries, and is an important cause of preventable blindness. Topical antifungals, particularly natamycin and voriconazole, are considered effective, but it is not clear which one is the best treatment alternative. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified three systematic reviews including three studies overall,all of which were randomized trials. We concluded natamycin probably is associated with better visual acuity after infection, and it prevents corneal perforation and/or need to perform therapeutic keratoplasty compared to voriconazole in fungal keratitis.

Incoherent-mediator for quantum state transfer in the ultrastrong coupling regime.

We study quantum state transfer between two qubits coupled to a common quantum bus that is constituted by an ultrastrong coupled light-matter system. By tuning both qubit frequencies on resonance with a forbidden transition in the mediating system, we demonstrate a high-fidelity swap operation even though the quantum bus is thermally populated. We discuss a possible physical implementation in a realistic circuit QED scheme that leads to the multimode Dicke model. This proposal may have applications on hot quantum information processing within the context of ultrastrong coupling regime of light-matter interaction.

Sudden Transition between Classical to Quantum Decoherence in bipartite correlated Qutrit Systems.

Classical to quantum decoherence transition, an issue existing for incoherent superposition of Bell-diagonal states is studied for three dimensional bipartite AB mixed quantum systems. Depending on the initial conditions, the dynamics of classical and quantum correlations can exhibit a sudden transition between classical to quantum decoherence. This result is calculated numerically by using entropic and geometric measures of correlations. An alternative explanation for this effect could be obtained by extending the bipartite A ⊗ B qutrit system to a pure tripartite A ⊗ B ⊗ C system. The freezing of classical correlations in AB is related to a freezing of the entanglement in the AC bipartition.

Transparent Memory For Harsh Electronics.

As a new class of non-volatile memory, resistive random access memory (RRAM) offers not only superior electronic characteristics, but also advanced functionalities, such as transparency and radiation hardness. However, the environmental tolerance of RRAM is material-dependent, and therefore the materials used must be chosen carefully in order to avoid instabilities and performance degradation caused by the detrimental effects arising from environmental gases and ionizing radiation. In this work, we demonstrate that AlN-based RRAM displays excellent performance and environmental stability, with no significant degradation to the resistance ratio over a 100-cycle endurance test. Moreover, transparent RRAM (TRRAM) based on AlN also performs reliably under four different harsh environmental conditions and 2 MeV proton irradiation fluences, ranging from 1011 to 1015 cm-2. These findings not only provide a guideline for TRRAM design, but also demonstrate the promising applicability of AlN TRRAM for future transparent harsh electronics.

Open lung approach ventilation abolishes the negative effects of respiratory rate in experimental lung injury.

BACKGROUND: We recently reported that a high respiratory rate was associated with less inflammation than a low respiratory rate, but caused more pulmonary edema in a model of ARDS when an ARDSNet ventilatory strategy was used. We hypothesized that an open lung approach (OLA) strategy would neutralize the independent effects of respiratory rate on lung inflammation and edema. This hypothesis was tested in an ARDS model using two clinically relevant respiratory rates during OLA strategy. METHODS: Twelve piglets were subjected to an experimental model of ARDS and randomized into two groups: LRR (20 breaths/min) and HRR (40 breaths/min). They were mechanically ventilated for 6 h according to an OLA strategy. We assessed respiratory mechanics, hemodynamics, and extravascular lung water (EVLW). At the end of the experiment, wet/dry ratio, regional histology, and cytokines were evaluated. RESULTS: After the ARDS model was established, Cdyn,rs decreased from 21 ± 3.3 to 9.0 ± 1.8 ml/cmH2 O (P < 0.0001). After the lung recruitment maneuver, Cdyn,rs increased to the pre-injury value. During OLA ventilation, no differences in respiratory mechanics, hemodynamics, or EVLW were observed between groups. Wet/dry ratio and histological scores were not different between groups. Cytokine quantification was similar and showed a homogeneous distribution throughout the lung in both groups. CONCLUSION: Contrary to previous findings with the ARDSNet strategy, respiratory rate did not influence lung inflammatory response or pulmonary edema during OLA ventilation in experimental ARDS. This indicates that changing the respiratory rate when OLA ventilation is used will not exacerbate lung injury.

High respiratory rate is associated with early reduction of lung edema clearance in an experimental model of ARDS.

BACKGROUND: The independent impact of respiratory rate on ventilator-induced lung injury has not been fully elucidated. The aim of this study was to investigate the effects of two clinically relevant respiratory rates on early ventilator-induced lung injury evolution and lung edema during the protective ARDSNet strategy. We hypothesized that the use of a higher respiratory rate during a protective ARDSNet ventilation strategy increases lung inflammation and, in addition, lung edema associated to strain-induced activation of transforming growth factor beta (TGF-ß) in the lung epithelium. METHODS: Twelve healthy piglets were submitted to a two-hit lung injury model and randomized into two groups: LRR (20 breaths/min) and HRR (40 breaths/min). They were mechanically ventilated during 6 h according to the ARDSNet strategy. We assessed respiratory mechanics, hemodynamics, and extravascular lung water (EVLW). At the end of the experiment, the lungs were excised and wet/dry ratio, TGF-ß pathway markers, regional histology, and cytokines were evaluated. RESULTS: No differences in oxygenation, PaCO2 levels, systemic and pulmonary arterial pressures were observed during the study. Respiratory system compliance and mean airway pressure were lower in LRR group. A decrease in EVLW over time occurred only in the LRR group (P < 0.05). Wet/dry ratio was higher in the HRR group (P < 0.05), as well as TGF-ß pathway activation. Histological findings suggestive of inflammation and inflammatory tissue cytokines were higher in LRR. CONCLUSION: HRR was associated with more pulmonary edema and higher activation of the TGF-ß pathway. In contrast with our hypothesis, HRR was associated with less lung inflammation.

High PEEP levels are associated with overdistension and tidal recruitment/derecruitment in ARDS patients.

BACKGROUND: Positive end-expiratory pressure (PEEP) improves gas exchange and respiratory mechanics, and it may decrease tissue injury and inflammation. The mechanisms of this protective effect are not fully elucidated. Our aim was to determine the intrinsic effects of moderate and higher levels of PEEP on tidal recruitment/derecruitment, hyperinflation, and lung mechanics, in patients with acute respiratory distress syndrome (ARDS). METHODS: Nine patients with ARDS of mainly pulmonary origin were ventilated sequential and randomly using two levels of PEEP: 9 and 15 cmH2 O, and studied with dynamic computed tomography at a fix transversal lung region. Tidal recruitment/derecruitment and hyperinflation were determined as non-aerated tissue and hyperinflated tissue variation between inspiration and expiration, expressed as percentage of total weight. We also assessed the maximal amount of non-aerated and hyperinflated tissue weight. RESULTS: PEEP 15 cmH2 O was associated with decrease in non-aerated tissue in all the patients (P < 0.01). However, PEEP 15 cmH2 O did not decrease tidal recruitment/derecruitment compared to PEEP 9 cmH2 O (P = 1). In addition, PEEP 15 cmH2 O markedly increased maximal hyperinflation (P < 0.01) and tidal hyperinflation (P < 0.05). Lung compliance decreased with PEEP 15 cmH2 O (P < 0.001). CONCLUSION: In this series of patients with ARDS of mainly pulmonary origin, application of high levels of PEEP did not decrease tidal recruitment/derecruitment, but instead consistently increased tidal and maximal hyperinflation.

Análisis comparativo in vitro del grado de filtración marginal de restauraciones de resina compuesta realizadas con dos métodos de grabado ácido distintos / In vitro comparative analysis of microleakage in composites resin restorations made with a conventional and a modified acid etch technique

La técnica de grabado ácido en esmalte representa el hito que marca la puerta de entrada para el establecimiento de la odontología adhesiva. Producto de que el sustrato adamantino pudiese presentar comportamiento refractario a la técnica convencional de grabado ácido es que se plantea una técnica en dos tiempos operatorios, la cual pudiese disminuir dicho comportamiento resistente al grabado ácido y combatir así el fenómeno de la filtración marginal de las resinas compuestas. En este estudio se utilizaron 30 terceros molares sanos, en los cuales se realizaron cavidades clases V en las caras vestibulares y linguales/palatinas, las cuales fueron obturadas con resina compuestas utilizando técnica de grabado ácido convencional y técnica de grabado ácido en dos tiempos operatorios, respectivamente. Estos especímenes fueron sometidos a un proceso de termociclado en presencia de un agente colorante marcador. Luego de un proceso de termociclado, las muestras fueron cortadas transversalmente para evaluar el porcentaje de penetración del agente marcador. El análisis de los resultados demostró que las restauraciones realizadas con técnica de grabado ácido en dos tiempos operatorios presentaron menores valores de filtración marginal, existiendo diferencias significativas entre ambos grupos estudiados.

The acid etch technique is the fact that marks the starting point for the establishment of the adhesive dentistry era. But as the enamel structure may have a resistant behavior towards the conventional acid etch technique ,a two-step acid etch technique is presented. This would diminish the aforementioned resistant behavior of enamel to the conventional acid etch technique, and minimize as well, the marginal leakage phenomenon of the composite materials. In this study 30 sound recently extracted molars were used. Equal class V cavities preparations were made in the buccal and palatal/lingual faces of each tooth. Buccal cavities were filled with composite before the use of the conventional acid etch technique, as adhesive method, while in the lingual/palatal faces the two-step acid etch technique was used. The samples were subjected to thermal cycles in the presence of a dying agent. After the thermocycling process, the samples were cut transversely to assess the percentage of penetration of the staining agent. The analysis of the results showed that there was a significant statistical difference between both groups. Moreover the restorations made with the two-step acid etch technique presented lower values of marginal leakage.

Dissonance is required for assisted optimal state discrimination.

The roles of quantum correlations, entanglement, discord, and dissonance needed for performing unambiguous quantum state discrimination assisted by an auxiliary system are studied. In general, this procedure for conclusive recognition between two nonorthogonal states relies on the availability of entanglement and discord. However, we find that there exist special cases for which the procedure can be successfully achieved without entanglement. In particular, we show that the optimal case for discriminating between two nonorthogonal states prepared with equal a priori probabilities does not require entanglement but quantum dissonance only.

Tidal volume is a major determinant of cyclic recruitment-derecruitment in acute respiratory distress syndrome.

BACKGROUND: Overdistension and cyclic recruitment-derecruitment contribute to ventilator-induced lung injury. High tidal volumes are thought to increase mortality mainly by inducing overdistension. However, experimental evidence suggests that tidal volume (VT) may also influence cyclic recruitment-derecruitment. Our main goal was to determine whether high tidal volumes increase cyclic recruitment-derecruitment in acute respiratory distress syndrome (ARDS) patients, as measured by dynamic computed tomography (CT). METHODS: We studied 9 ARDS patients with diffuse attenuations on CT who underwent a protocol including 2 ventilatory modes: (a) VT 6 mL/kg, respiratory rate 30/min, PEEP 9 cmH2O, (b) VT 12 mL/kg, respiratory rate 15/min, PEEP 9 cmH2O. A dynamic computed tomography of 8 seconds on a fixed transverse region was performed during each ventilator mode. Cyclic recruitment-derecruitment was determined as non-aerated tissue variation between inspiration and expiration and was expressed as % of lung tissue weight. RESULTS: VT 12 mL/kg exhibited less non-aerated tissue at expiration compared to VT 6 ml/kg (40.15 [35.94-56.00] and 45.31 [37.95-59.32], respectively, P<0.05). However, VT 12 ml/kg increased cyclic recruitment-derecruitment compared to VT 6 mL/kg (7.32 [6.58-9.29] mL/kg vs. 4.51 [3.42-5.75] mL/kg, P<0.01). Tidal hyperinflation was also larger at VT 12 mL/kg (0.55 [0.27-2.24] vs. 0.24 [0.18-0.83], P<0.01). CONCLUSION: High tidal volume is a major determinant of cyclic recruitment-derecruitment in ARDS patients with diffuse attenuations.

Sudden birth versus sudden death of entanglement in multipartite systems.

We study the entanglement dynamics of two cavities interacting with independent reservoirs. Expectedly, as the cavity entanglement is depleted, it is transferred to the reservoir degrees of freedom. We find also that when the cavity entanglement suddenly disappears, the reservoir entanglement suddenly and necessarily appears. Surprisingly, we show that this entanglement sudden birth can manifest before, simultaneously, or even after entanglement sudden death. Finally, we present an explanatory study of other entanglement partitions and of higher dimensional systems.

Field squeeze operators in optical cavities with atomic ensembles.

We propose a method of generating unitarily single and two-mode field squeezing in an optical cavity with an atomic cloud. Through a suitable laser system, we are able to engineer a squeeze field operator decoupled from the atomic degrees of freedom, yielding a large squeeze parameter that is scaled up by the number of atoms, and realizing degenerate and nondegenerate parametric amplification. By means of the input-output theory we show that ideal squeezed states and perfect squeezing could be approached at the output. The scheme is robust to decoherence processes.

Scaling approach to the magnetic phase diagram of nanosized systems.

Based on the discovery of a simple scaling relation, a new technique for the investigation of the phase diagram of nanosized magnetic systems is proposed. By scaling the exchange interaction between magnetic moments, the magnetic phase diagram of currently lithographically produced particles can be obtained from those corresponding to much smaller systems. Such a technique reduces the computation time by several orders of magnitude, and provides a new approach to the investigation of the relative stability of distinct internal magnetic configurations of nanosized systems. The technique is illustrated by the determination of the phase diagram of cylindrically shaped Co particles.