Geological evidence of extensive N-fixation by volcanic lightning during very large explosive eruptions.

Most of the nitrogen (N) accessible for life is trapped in dinitrogen (N2), the most stable atmospheric molecule. In order to be metabolized by living organisms, N2 has to be converted into biologically assimilable forms, so-called fixed N. Nowadays, nearly all the N-fixation is achieved through biological and anthropogenic processes. However, in early prebiotic environments of the Earth, N-fixation must have occurred via natural abiotic processes. One of the most invoked processes is electrical discharges, including from thunderstorms and lightning associated with volcanic eruptions. Despite the frequent occurrence of volcanic lightning during explosive eruptions and convincing laboratory experimentation, no evidence of substantial N-fixation has been found in any geological archive. Here, we report on the discovery of a significant amount of nitrate in volcanic deposits from Neogene caldera-forming eruptions, which are well correlated with the concentrations of species directly emitted by volcanoes (sulfur, chlorine). The multi-isotopic composition (δ18O, Δ17O) of the nitrates reveals that they originate from the atmospheric oxidation of nitrogen oxides formed by volcanic lightning. According to these first geological volcanic nitrate archive, we estimate that, on average, about 60 Tg of N can be fixed during a large explosive event. Our findings hint at a unique role potentially played by subaerial explosive eruptions in supplying essential ingredients for the emergence of life on Earth.

Improved Feedback Quantizer with Discrete Space Vector.

The use of advanced modulation and control schemes for power converters, such as a Feedback Quantizer and Predictive Control, is widely studied in the literature. This work focuses on improving the closed-loop modulation scheme called Feedback Quantizer, which is applied to a three-phase voltage source inverter. This scheme has the natural behavior of mitigating harmonics at low frequencies, which are detrimental to electrical equipment such as transformers. This modulation scheme also provides good tracking for the voltage reference at the fundamental frequency. On the other hand, the disadvantage of this scheme is that it has a variable switching frequency, creating a harmonic spectrum in frequency dispersion, and it also needs a small sampling time to obtain good results. The proposed scheme to improve the modulation scheme is based on a Discrete Space Vector with virtual vectors to obtain a better approximation of the optimal vectors for use in the algorithm. The proposal improves the conventional scheme at a high sampling time (200 µs), obtaining a THD less than 2% in the load current, decreases the noise created by the conventional scheme, and provides a fixed switching frequency. Experimental tests demonstrate the correct operation of the proposed scheme.

Neuro-cranio-vertebral syndrome related to coccygeal dislocation: A preliminary study.

Background: Neuro-cranio-vertebral syndrome (NCVS) includes a set of idiopathic diseases: Arnold-Chiari syndrome type 0,1 and 1.5, idiopathic scoliosis, and idiopathic syringomyelia. It is caused by the pathological traction transmitted by the filum terminale on the neuraxis. Considering that the filum terminale is inserted at sacrococcygeal level, it is logical to think that an alteration of this segment's anatomy, such as an anterior coccyx dislocation, can increase the tension exerted by the filum terminale on the neuraxis, which in turn triggers NCVS. Methods: We collected data from 372 patients with NCVS and 15 patients with coccygeal dislocation and NCVS from our database. We analyzed the relationship between the sacrococcygeal and intercoccygeal angles with signs, symptoms and associated diagnoses. T-tests for independent samples and linear regression were used for analysis (p <0.05). We describe the MRI findings and clinical features of NCVS caused by coccygeal dislocation and compare its prevalence with that of a sample without coccygeal dislocation. Results: 65% of the signs, symptoms, and imaging features were present in similar proportions in both samples. There was a similar prevalence of cerebellar tonsillar descent and scoliosis in both groups, whereas the incidence of syringomyelia differed. A sacrococcygeal angle between 89-110° prevails in cases of syringomyelia while an intercoccygeal angle between 90-140° prevails in cases with cerebellar tonsillar descent. Conclusions: The high clinical and radiological prevalence of coccygeal dislocation in patients with Neuro-cranio-vertebral syndrome suggests an association between them. The mechanism involved in coccygeal dislocation can directly influence the development of Neuro-cranio-vertebral syndrome.

A Detailed dSPACE-Based Implementation of Modulated Model Predictive Control for AC Microgrids.

Microgrids represent a promising energy technology, because of the inclusion in them of clean and smart energy technologies. They also represent research challenges, including controllability, stability, and implementation. This article presents a dSPACE-control-platform-based implementation of a fixed-switching-frequency modulated model predictive control (M2PC) strategy, as an inner controller of a two-level, three-phase voltage source inverter (VSI) working in an islanded AC microgrid. The developed controller is hierarchical, as it includes a primary controller to share the load equally with the other power converter with its own local modulated predictive-based controller. All details of the implementation are given for establishing the dSPACE-based implementation of the control on a dSPACE ds1103 control platform, using MATLAB/Simulink for the controller design, I/O implementation and configuration with the embedded dSPACE's real-time interface in Simulink, and then using the ControlDesk software for monitoring and testing of the real plant. The latter consists of the VSI operating with LCL filters, and sharing an RL load with a paralleled VSI with exactly the same controller. Finally, the obtained experimental waveforms are shown, with our respective conclusions representing this work, which is a very valuable tool for helping microgrid researchers implement dSPACE-based real-time simulations.

Moving Microgrid Hierarchical Control to an SDN-Based Kubernetes Cluster: A Framework for Reliable and Flexible Energy Distribution.

Software Defined Networking (SDN) is a communication alternative to increase the scalability and resilience of microgrid hierarchical control. The common architecture has a centralized and monolithic topology, where the controller is highly susceptible to latency problems, resiliency, and scalability issues. This paper proposes a novel and intelligent control network to improve the performance of microgrid communications, solving the typical drawback of monolithic SDN controllers. The SDN controller's functionalities are segregated into microservices groups and distributed through a bare-metal Kubernetes cluster. Results are presented from PLECS hardware in the loop simulation to validate the seamless transition between standard hierarchical control to the SDN networked microgrid. The microservices significantly impact the performance of the SDN controller, decreasing the latency by 10.76% compared with a monolithic architecture. Furthermore, the proposed approach demonstrates a 42.23% decrease in packet loss versus monolithic topologies and a 53.41% reduction in recovery time during failures. Combining Kubernetes with SDN microservices can eliminate the single point of failure in hierarchical control, improve application recovery time, and enhance containerization benefits, including security and portability. This proposal represents a reference framework for future edge computing and intelligent control approaches in networked microgrids.

High Pulsed Voltage Alkaline Electrolysis for Water Splitting.

Pulsed electrolysis has become a promising research topic in recent decades due to advances in solid-state semiconductor devices. These technologies have enabled the design and construction of simpler, more efficient, and less costly high-voltage and high-frequency power converters. In this paper, we study high-voltage pulsed electrolysis considering variations in both power converter parameters and cell configuration. Experimental results are obtained for frequency variations ranging from 10 Hz to 1 MHz, voltage changes from 2 V to 500 V, and electrode separations from 0.1 to 2 mm. The results demonstrate that pulsed plasmolysis is a promising method for decomposing water for hydrogen production.

A Smart Crop Water Stress Index-Based IoT Solution for Precision Irrigation of Wine Grape.

The Scholander-type pressure chamber to measure midday stem water potential (MSWP) has been widely used to schedule irrigation in commercial vineyards. However, the limited number of sites that can be evaluated using the pressure chamber makes it difficult to evaluate the spatial variability of vineyard water status. As an alternative, several authors have suggested using the crop water stress index (CWSI) based on low-cost thermal infrared (TIR) sensors to estimate the MSWP. Therefore, this study aimed to develop a low-cost wireless infrared sensor network (WISN) to monitor the spatial variability of MSWPs in a drip-irrigated Cabernet Sauvignon vineyard under two levels of water stress. For this study, the MLX90614 sensor was used to measure canopy temperature (Tc), and thus compute the CWSI. The results indicated that good performance of the MLX90614 infrared thermometers was observed under laboratory and vineyard conditions with root mean square error (RMSE) and mean absolute error (MAE) values being less than 1.0 °C. Finally, a good nonlinear correlation between the MSWP and CWSI (R2 = 0.72) was observed, allowing the development of intra-vineyard spatial variability maps of MSWP using the low-cost wireless infrared sensor network.

FCS-MPC with Nonlinear Control Applied to a Multicell AFE Rectifier.

The use of controlled power converters has been extended for high power applications, stacking off-the-shelve semiconductors, and allowing the implementation of, among others, AC drives for medium voltages of 2.3 kV to 13.8 kV. For AC drives based on power cells assembled with three-phase diode rectifiers and cascaded H-bridge inverters, a sophisticated input multipulse transformer is required to reduce the grid voltage, provide isolation among the power cells, and compensate for low-frequency current harmonics generated by the diode-based rectifiers. However, this input multipulse transformer is bulky, heavy, and expensive and must be designed according to the number of power cells, not allowing total modularity of the AC drives based on cascade H-bridges. This study proposes and evaluates a control strategy based on a finite control set-model predictive control that emulates the harmonic cancellation performed by an input multipulse transformer in a cascade H-bridge topology. Hence, the proposed method requires conventional input transformers and replaces the three-phase diode rectifiers. As a result, greater modularity than the conventional multicell converter and improved AC overall input current with a THD as low as 2% with a unitary displacement power factor are achieved. In this case, each power cell manages its own DC voltage using a nonlinear control strategy, ensuring stable system operation for passive and regenerative loads. The experimental tests demonstrated the correct performance of the proposed scheme.

Awake prone positioning and oxygen therapy in patients with COVID-19: the APRONOX study.

BACKGROUND: The awake prone positioning strategy for patients with acute respiratory distress syndrome is a safe, simple and cost-effective technique used to improve hypoxaemia. We aimed to evaluate intubation and mortality risk in patients with coronavirus disease 2019 (COVID-19) who underwent awake prone positioning during hospitalisation. METHODS: In this retrospective, multicentre observational study conducted between 1 May 2020 and 12 June 2020 in 27 hospitals in Mexico and Ecuador, nonintubated patients with COVID-19 managed with awake prone or awake supine positioning were included to evaluate intubation and mortality risk through logistic regression models; multivariable and centre adjustment, propensity score analyses, and E-values were calculated to limit confounding. RESULTS: 827 nonintubated patients with COVID-19 in the awake prone (n=505) and awake supine (n=322) groups were included for analysis. Fewer patients in the awake prone group required endotracheal intubation (23.6% versus 40.4%) or died (19.8% versus 37.3%). Awake prone positioning was a protective factor for intubation even after multivariable adjustment (OR 0.35, 95% CI 0.24-0.52; p<0.0001, E=2.12), which prevailed after propensity score analysis (OR 0.41, 95% CI 0.27-0.62; p<0.0001, E=1.86) and mortality (adjusted OR 0.38, 95% CI 0.26-0.55; p<0.0001, E=2.03). The main variables associated with intubation among awake prone patients were increasing age, lower baseline peripheral arterial oxygen saturation/inspiratory oxygen fraction ratio (P aO2 /F IO2 ) and management with a nonrebreather mask. CONCLUSIONS: Awake prone positioning in hospitalised nonintubated patients with COVID-19 is associated with a lower risk of intubation and mortality.

Review of Control Techniques in Microinverters.

The use of renewable energies sources is taking great importance due to the high demand for electricity and the decrease in the use of fossil fuels worldwide. In this context, electricity generation through photovoltaic panels is gaining a lot of interest due to the reduction in installation costs and the rapid advance of the development of new technologies. To minimize or reduce the negative impact of partial shading or mismatches of photovoltaic panels, many researchers have proposed four configurations that depend on the power ranges and the application. The microinverter is a promising solution in photovoltaic systems, due to its high efficiency of Maximum Power Point Tracking and high flexibility. However, there are several challenges to improve microinverter's reliability and conversion efficiency that depend on the proper control design and the power converter design. This paper presents a review of different control strategies in microinverters for different applications. The control strategies are described and compared based on stability, dynamic response, topologies, and control objectives. One of the most important results showed that there is little research regarding the stability and robustness analysis of the reviewed control strategies.

What is the radiation before 5G? A correlation study between measurements in situ and in real time and epidemiological indicators in Vallecas, Madrid.

BACKGROUND: Exposure of the general population to electromagnetic radiation emitted by mobile phone base stations is one of the greater concerns of residents affected by the proximity of these structures due to the possible relationship between radiated levels and health indicators. OBJECTIVES: This study aimed to find a possible relationship between some health indicators and electromagnetic radiation measurements. METHODS: A total of 268 surveys, own design, were completed by residents of a Madrid neighborhood surrounded by nine telephone antennas, and 105 measurements of electromagnetic radiation were taken with a spectrum analyzer and an isotropic antenna, in situ and in real - time, both outside and inside the houses. RESULTS: It was shown statistically significant p - values in headaches presence (p = 0.010), nightmares (p = 0.001), headache intensity (p < 0.001), dizziness frequency (p = 0.011), instability episodes frequency (p = 0.026), number of hours that one person sleeps per day (p < 0.001) and three of nine parameters studied from tiredness. Concerning cancer, there are 5.6% of cancer cases in the study population, a percentage 10 times higher than that of the total Spanish population. DISCUSSION: People who are exposed to higher radiation values present more severe headaches, dizziness and nightmares. Moreover, they sleep fewer hours.

The Filum disease and the Neuro-Cranio-vertebral syndrome: definition, clinical picture and imaging features.

BACKGROUND: We propose two new concepts, the Filum Disease (FD) and the Neuro-cranio-vertebral syndrome (NCVS), that group together conditions thus far considered idiopathic, such as Arnold-Chiari Syndrome Type I (ACSI), Idiopathic Syringomyelia (ISM), Idiopathic Scoliosis (IS), Basilar Impression (BI), Platybasia (PTB) Retroflexed Odontoid (RO) and Brainstem Kinking (BSK). METHOD: We describe the symptomatology, the clinical course and the neurological signs of the new nosological entities as well as the changes visible on imaging studies in a series of 373 patients. RESULTS: Our series included 72% women with a mean age of 33.66 years; 48% of the patients had an interval from onset to diagnosis longer than 10 years and 64% had a progressive clinical course. The commonest symptoms were: headache 84%, lumbosacral pain 72%, cervical pain 72%, balance alteration 72% and paresthesias 70%. The commonest neurological signs were: altered deep tendon reflexes in upper extremities 86%, altered deep tendon reflexes in lower extremities 82%, altered plantar reflexes 73%, decreased grip strength 70%, altered sensibility to temperature 69%, altered abdominal reflexes 68%, positive Mingazzini's test 66%, altered sensibility to touch 65% and deviation of the uvula and/or tongue 64%. The imaging features most often seen were: altered position of cerebellar tonsils 93%, low-lying Conus medullaris below the T12L1 disc 88%, idiopathic scoliosis 76%, multiple disc disease 72% and syringomyelic cavities 52%. CONCLUSIONS: This is a paradigm shift that opens up new paths for research and broadens the range of therapeutics available to these patients.

Ventilación en posición prono en pacientes postoperados de cirugía abdominal complicados con síndrome de dificultad respiratoria aguda: análisis de una cohorte / Prone position ventilation in abdominal surgery patients complicated with acute respiratory distress syndrome: analysis of a cohort / Ventilação em posição prona em pacientes submetidos à cirurgia abdominal complicados com SDRA: análise de uma coorte

Resumen: Introducción: Las complicaciones postoperatorias a nivel pulmonar son causa de morbilidad y mortalidad, particularmente cuando desarrollan síndrome de dificultad respiratoria aguda y requieren ventilación mecánica; uno de los métodos empleados para pacientes que no responden al manejo ventilatorio convencional es la posición prono; sin embargo, hay poca evidencia sobre ventilación en prono en pacientes quirúrgicos abdominales. Material y métodos: Se revisó una cohorte de pacientes ventilados en prono para analizar el comportamiento de los cortocircuitos pulmonares y el índice PaO2/FiO2 antes, durante y después de la ventilación en prono. Resultados: Se observó una disminución significativa de los cortocircuitos pulmonares a partir de las 48 horas, mientras que el aumento de la PaO2/FiO2 fue significativa a partir de las 12 horas de prono; no se revisaron eventos adversos relevantes durante la pronación. Conclusiones: La ventilación en posición prono es una maniobra segura que provee una opción terapéutica en pacientes refractarios a manejo convencional, incluso durante el postquirúrgico de abdomen.

Abstract: Introduction: Postoperative complications at the respiratory level are a cause of morbidity and mortality, particularly when they develop acute respiratory distress syndrome and require mechanical ventilation; one of the methods used for patients who do not respond to conventional ventilatory management is the prone position, however, there is little evidence on prone ventilation in abdominal surgical patients. Material and methods: A cohort of patients ventilated in prone was reviewed to analyze the behavior of pulmonary shunts and the PaO2/FiO2 index before, during and after prone ventilation. Results: A significant decrease in pulmonary shunts was observed after 48 hours, while the increase in PaO2/FiO2 was significant after 12 hours of prone; no serioud adverse events were recorded during pronation. Conclusions: The prone position is a safe ventilatory maneuver that provides a therapeutic option in patients refractory to conventional management, even during abdominal post-surgery.

Resumo: Introdução: As complicações pós-operatórias a nível pulmonar causam morbimortalidade, principalmente quando desenvolvem síndrome do desconforto respiratório agudo e requerem ventilação mecânica; um dos métodos utilizados para pacientes que não respondem ao tratamento ventilatório convencional é a posição prona, no entanto, existem poucas evidências sobre a ventilação prona em pacientes cirúrgicos abdominais. Material e métodos: Uma coorte de pacientes ventilados em decúbito prona foi revisada para analisar o comportamento dos shunts pulmonares e o índice de PaO2/ FiO2 antes, durante e após a ventilação prona. Resultados: Foi observada uma diminuição significativa dos curtos-circuitos pulmonares após 48 horas, enquanto o aumento da PaO2/ FiO2 foi significativo após 12 horas; nenhum evento adverso relevante foi verificado durante a pronação. Conclusões: A ventilação prona é uma manobra segura que oferece uma opção terapêutica em pacientes refratários ao tratamento convencional, mesmo durante o abdome pós-cirúrgico.

Data for resistance and inductance estimation within a voltage source inverter.

Power converters are essential for the use of renewable energy resources. For example, a photovoltaic system produces DC energy that is transformed into AC by the voltage source inverter (VSI). This power is used by a motor drive that operates at different speeds, generating variable loads. Two parameters, namely, resistance and inductance are essential to correctly adjust the model predictive control (MPC) in a VSI. In this paper, we describe the data from a VSI that incorporates an MPC. We generate four datasets consisting of 399 cases or instances (rows) each one. Two data set comprises the simulations varying the inductance (continuous and discrete versions) and the other two varying the resistance (continuous and discrete versions). The motivation behind this data is to support the design and development of nonintrusive models to predict the resistance and inductance of a VSI under different conditions.

Coronary Angioplasty with Stent in Woman with Active Vaginal Bleeding

Uterine leiomyoma and coronary artery disease are two common diseases in women. However, the association of uterine bleeding caused by leiomyoma with unstable coronary syndrome is not frequent. Here we describe a case of a patient with active vaginal bleeding and unstable angina who underwent a unique approach by performing percutaneous procedures. The report demonstrates that new interventional options can be used to control active bleeding in patients in need of coronary angioplasty

Multiple vertebral fractures at the "dr. manuel dufoo" spine clinic / Fraturas vertebrais múltiplas na clínica de coluna "dr. manuel dufoo" / Fracturas vertebrales múltiples en la clínica de columna "dr. manuel dufoo"

ABSTRACT Objective: To establish the frequency of presentation of multiple vertebral fractures and evaluate the relationship between the postsurgical condition and the initial neurological lesion, as well as to report the associated injuries in this group of patients. Methods: We conducted a review of patients with spinal trauma and a diagnosis of multiple vertebral fractures who were admitted to the "Dr. Manuel Dufoo Olvera" Spine Clinic of the Secretary of Health of Mexico City from January 1,2014 to June 30, 2017. The multiple fractures were classified as either contiguous or non-contiguous, according to the number of vertebral bodies and levels affected. The statistical analysis was conducted using formulas of descriptive statistics and the information was then tabulated and graphed to assess the relationship between the anatomical classification and the degree of neurological injury. Results: We observed 530 patients, of whom 47 met the criteria. Thirty-one (65.95%) of the cases corresponded to contiguous fractures and 16 cases (34.05%) to non-contiguous fractures. Fourteen patients (29.78%) with neurological integrity were classified as ASIA D, 20 patients (42.58%) with complete lesion as ASIA A, 7 seven patients (14.89%) as ASIA B, and 6 patients (12.76%) with partial injury as ASIA C. Conclusions: The correlation between the classification of vertebral injuries and the presence of neurological lesion did not show significant differences between contiguous and non-contiguous fractures. Level of Evidence II; Retrospective.

RESUMO Objetivos: Estabelecer a frequência de apresentação de múltiplas fraturas vertebrais e avaliar a relação de sua condição pós-cirúrgica e a lesão neurológica inicial, bem como relatar as lesões associadas neste grupo de pacientes. Métodos: Uma revisão dos casos com traumatismo espinhal e diagnóstico de fratura vertebral múltipla, que entraram no Spine Clinic " Dr Manuel Dufoo Olvera " Secretário da Cidade do México saúde da coluna vertebral, durante o período de 1 de janeiro de 2014 a 30 de Junho de 2017. A classificação divide fraturas múltiplas como contíguas e não contíguas, seguido pelo número de pessoas afetadas e os corpos de nível. A análise estatística foi realizada utilizando fórmulas statística descritivas, então tabuladas e as informações representadas graficamente. Para avaliar a relação entre a classificação anatômica e do grau de lesão neurológica. Resultados: 530 Pacientes foram observados, dos quais 47 apresentaram os critérios necessários. 31 pacientes (65,95%) do estudo foram classificados com fraturas adjacentes contíguas e 16 casos (34,05%) como não contíguas. 14 doentes (29,78%) foram classificados com integridade neurológica ÁSIA D, 20 doentes (42,58%) apresentaram lesão completa ÁSIA A, sete doentes (14,89%) na ASIA B e seis doentes. (12,76%) com lesão incompleta ÁSIA C. Conclusão: A correlação entre a classificação das lesões da coluna vertebral e a presença de lesão neurológica não mostraram diferenças significativas entre fraturas adjacentes e não adjacentes. Nível de Evidência II; Restrospectivo.

RESUMEN Objetivo: Establecer la frecuencia de presentación de las fracturas vertebrales múltiples y evaluar la relación de su condición postquirúrgica y la lesión neurológica inicial, así como relatar las lesiones asociadas en este grupo de pacientes. Métodos: Se realiza una revisión de los casos con traumatismo raquimedular y diagnóstico de fractura vertebral múltiple que ingresaron a la Clínica de Columna "Dr. Manuel Dufoo Olvera" de la Secretaría de Salud de Ciudad de México del 1° de enero de 2014 al 30 de junio del 2017. La clasificación divide las fracturas múltiples como contiguas y no contiguas, acorde al número de cuerpos afectados y el nivel.. El análisis estadístico se realizó utilizando fórmulas de estadística descriptiva, para después tabular y graficar la información, para evaluar la relación entre la clasificación anatómica y el grado de lesión neurológica. Resultados: Fueron observados 530 pacientes, de los cuales 47 presentaron los criterios necesarios. Treinta y un pacientes (65,95%) del estudio fueron clasificados con fracturas contiguas y 16 casos (34,05%) con no contiguas. Catorce pacientes (29,78%) fueron clasificados con integridad neurológica ASIA D, 20 pacientes (42,58%) presentaron lesión completa ASIA A, siete pacientes (14,89%) en ASIA B y seis pacientes (12,76%) con lesión incompleta ASIA C. Conclusiones: La correlación entre la clasificación de lesión de columna vertebral y la presencia de lesión neurológica no mostró diferencias significativas entre fracturas contiguas y no contiguas. Nivel de Evidencia II; Retrospectivo.