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This article proposes a novel optimal hybrid control framework to improve the voltage profile of highly unbalanced Distribution Grids (DGs) by coordinating the injection of reactive power from multiple off-board Electrical Vehicles (EVs) chargers. It exploits the time-synchronized measurements advantages, centralized control, and local controllers embedded into a hierarchical and scalable scheme, coordinated by the distribution system operator (DSO). The proposed framework is aimed to increase the modern electrical networks’ flexibility, reliability, and stability. It is powered by the Eigensystem Realization (ER)-based system identification technique, a Linear Quadratic Gaussian (LQG) controller, the Distribution-level Phasor Measurement Units (D-PMUs), and a new aggregator agent that handles the EV chargers power injection to precisely and timely regulate the dynamic voltage response in a sub-area or the entire DG. The robustness and feasibility of the proposal are demonstrated by employing simulated scenarios with unbalanced faults, latency in communications, and highly unbalanced loads conditions on the IEEE 13 and 123 nodes test feeders, compensating the voltage variations accurately in less than 205 ms. The promising outcome of this study suggests a novel application for an emerging measurement-based control system in the operation of modern active DGs.

Objective: This study will analyze the effects of the most common substances in medical students and their impact on their academic performance. Method:328 medical students were interviewed between April 2019 to March 2020 for this study. In this cross-sectional study, information regarding substance use habits among medical students was obtained through a survey. The information was obtained through a questionnaire that is made up of 6 pages with the following sections: Registration, consumption of alcohol, marijuana, cocaine, medication to improve academic performance and energy drinks. Results:The results in this investigation were the following: the use of alcohol showed that it has a low relevance in influencing the performance of the students (p=0.702), the use of marijuana showed that it has a low relevance in the performance (p= 0.527), the use of cocaine showed that it has a low relevance in influencing academic performance (p=0.560), the use of medications showed that they have a high relevance in influencing academic performance (p=0.001), the use of energy drinks showed that they have a low relevance in influencing the performance of medical students (p=0.346). Conclusions:The use of substances among university students has been increasing over the years, the importance of understanding this phenomenon and its repercussions on students can help prevent addictions, school dropouts and even deaths from overdoses, as described in various literatures.

Current advances in industrial biotechnology are expanding the breadth of what is possible through the use of microbial cell factories. With global resources being exhausted at rapid rates and a heavy reliance on nonrenewable feedstocks, there is pressure to find alternatives using biorenewables. Application of these products is widespread, from reducing petroleum-based demand in the chemical industry, to synthesizing next-generation drug therapeutics at low cost. At the center of this biobased innovation is the need for a workhorse microorganism, capable of efficiently manufacturing these target molecules. In the context of biorenewable compounds, there are many cases where bacteria are not an option due to host toxicity or lack of processing ability, for example, post-translational modification. Baker’s yeast, Saccharomyces cerevisiae, is an ideal candidate as it is well characterized and frequently used industrially. Here we report its use in producing the polyketide triacetic acid lactone (TAL), an important polyketide which can be readily converted to replace fossil-fuel derived counterparts. Due to the complexity inherent in any host cell, metabolic pathway engineering was performed on central carbon metabolism to increase availability of acetyl-CoA and malonyl-CoA metabolites. The computational tool OptKnock in conjunction with other knockout interventions were used to create a strain (BY4741Δprb1Δpyc2Δnte1Δyia6) producing 2.2 g/L TAL, 26% of the theoretical yield on glucose, in fed-batch fermentation. In addition, enzyme engineering of the Gerbera hybrida 2-pyrone synthase (2-PS) catalyzing TAL formation was conducted and then evaluated in our strains. This effort screened 41 2-PS variants and elucidated key residues in the active site and the protein surface, improving catalytic efficiency and/or stability, leading to 2.5-fold increases in TAL levels in S. cerevisiae. The surface-modified variant 2-PS (C35S, C372S) exhibited the highest kcat/Km, over 40 times that of the native synthase. This variant was introduced into an engineered strain (BJ5464Δpyc2Δnte1) and cultivated in glucose or ethanol fed-batch to yield 2.7 g/L and 4.2 g/L TAL, respectively. Fermentation parameters were further improved and feed components modified for high titer (7.6 g/L) and yield (44% of theoretical) of this polyketide. Enhancement of precursor availability was also achieved by using a heterologous pathway from Escherichia coli. A modified E. coli bacterial pyruvate dehydrogenase (PDHm) was introduced in a cofactor-limited (Δzwf1) strain to couple NADPH cofactor balance with the synthesis of the TAL precursor acetyl-CoA. To prevent loss of acetyl-CoA and pyruvate by transport to the mitochondria, recently elucidated pathways were disrupted (Δpor2Δmpc2Δpda1Δyat2). The coupling of all three approaches (Δzwf1Δpor2Δmpc2Δpda1Δyat2+PDHm) elevated titers to 1.6 g/L, the highest by batch cultivation (and 35% of theoretical yield). These strategies are directly applicable to the synthesis of other acetyl-CoA derived compounds, and these studies provide a framework to develop design principles for robust, industrially relevant yeast for the synthesis of polyketides.

Transients caused by lightning that strikes to transmission lines, switching operations or faults, are fundamentals in selecting equipment insulation levels and protection devices. Thus, studies of electromagnetic transients on transmission lines have demonstrated that when a change on the normal operation of the system takes place, voltage and currents traveling waves appear and these are reflected and refracted in the transmission line. In this paper, an ATPDraw simulator is developed to observe the propagation of voltage and current traveling waves along the transmission lines. The Bewley's Lattice diagram is used into the simulator to show in a comprehensive manner the behavior of the traveling waves. The behavior of the traveling waves is strictly depending on the reflection and refraction coefficients in the sending and receiving nodes, in turn these coefficients are depending on the transmission network's parameters, such as the characteristic impedance and the impedance of the sending and receiving ends.

La investigación se realizó en la empresa consultora Solución Inocua S.A. y el objetivo general fue determinar la relación existente entre la gestión de competencias basado en las dimensiones del saber (saber conocer, saber hacer, saber actuar y saber ser) y el desempeño de los profesionales de la empresa consultora Solución Inocua S.A. La investigación fue de tipo correlacional aplicada y de corte transversal, cuyo diseño fue no experimental y de enfoque cualitativo, La población estuvo constituido por 45 profesionales de la empresa. La técnica fue la encuesta. El cuestionario fue sometido a validez de contenido, utilizando juicio de expertos sintetizando sus calificaciones mediante la prueba V de Aiken. Este tipo de validez, fue complementado con la de constructo utilizando los análisis AFE y AFC evidenciando indicadores robustos. Según los resultados se concluye mediante la evidencia de Rho de Spearman una correlación significativa entre la gestión por competencias y el desempeño laboral de 71%, El modelo confirmatorio señala robustez en sus factores Gestión por competencias en promedio 60.5% y desempeño 88% y define que la relación entre ambos es de 93%. Lima Este Escuela de Posgrado Gestión de Organizaciones

Wide-area monitoring systems (WAMS) are spread in many power systems around the world, which demonstrate their significance and potential for power system operators. Thus, this paper emphasizes the use of synchronized-measurements-driven applications in power systems. To this end, two Matlab-embedded applications are developed using the graphical user interface (GUI) environment of Matlab. The former provides synchrophasor estimates that are processed and stored by means of a phasor estimation algorithm and a database, respectively; meanwhile the latter consists of a power system modal monitor application that is able to capture the modal information corresponding to low frequency oscillations (LFOs) in power systems. Also, the DIgSILENT PowerFactory environment is employed for running EMT simulations, whose results provide instantaneous signals to the phasor estimation stage in Matlab. Finally, results exhibit a WAMS simulator dealing with a LFO captured by PMUs, showing the performance of three traditional technique for identifyina electromechanical modes in power systems.

This paper proposes a robust adaptive hybrid optimization approach taking advance of two meta-heuristic algorithms to solve the non-convex economic dispatch (ED) problem in large-scale power grids. The demanded load is continuously increasing, leading to the operators to cope with new challenges associated with the reduction of the generation costs. As a consequence of this unmeasured increasing, algorithms with flexible and soft computing capabilities for analysing large-scale power systems are required. Thus, the key idea behind the proposed hybrid optimization framework is based on the abilities of the adaptive simulated annealing (ASA) and genetic operators for evaluating the economic dispatch problem, since these accelerate the convergence and reduce the total number of evaluations. This proposal optimizes the solution of the non-convex ED problem, decreasing the generation costs and emissions, and demonstrating a better performance during its convergence characteristics. Numerical tests are carried out in two power grids, where a reduced version of the Mexican interconnected power system is considered with a 24-h wind profile, aiming to demonstrate the superiority of this work, and show the new advantages regarding other algorithms.

This article presents the use of an interactive computer tool developed in MATLAB® called RISKASSESSMENT v1.0, to perform market risk analysis of commercial products, through the development of cash flow, sensitivity analysis, and SpiderPlot graphics, which allow the identification of the economic-financial equilibrium point of a company. The tool facilitates the reduction of the uncertainty produced in the return on investment due to changes in the economic environment of the sector in which the company operates, through statistical techniques and tools that involve parameters such as the annual effective rate in the Colombian national currency, net present value, internal rate of return, period of recovery of capital, through a sensitivity analysis. To validate the effectiveness of using software in the development of risk analysis, a case study was conducted for an alcohol beverage sales business, where, based on the portfolio containing the product quantity, unit variable cost, sales price, percentage of sales growth and annual sales volume, in addition to detailed information on the initial investment, the cash flow with a 5-year horizon, the net present value, the internal rate of return, the period of capital recovery and the average accounting profitability are calculated. The tool also performs sensitivity analysis and SpiderPlot for each of the products. Finally, the program presented allows to calculate the annual cash flows in a fast and didactic way, which normally requires time and specialized training in a traditional exercise.

O objetivo deste estudo foi avaliar o efeito da suplementação durante pré e/ou pós-parto no desempenho, características nutricionais e metabólicas das vacas Nelore pastejando Brachiaria decumbens. O experimento foi conduzido durante 120 dias, de julho a novembro, durante a estação seca e o período de transição entre seco e chuvoso. Para o experimento, foram utilizadas 48 vacas Nelore multíparas, com idade média de 6 anos. O peso corporal médio (PC) e escore de condição corporal (ECC) no início do experimento foram de 501±55 kg e 5,4±0,65, respectivamente. O experimento foi realizado de acordo com um delineamento inteiramente casualizado, seguindo um esquema fatorial 2 × 2, onde duas estratégias de suplementação foram testadas, suplementação (1 kg/d com 20% de proteína bruta, PB) e sem suplementação, durante dois períodos, pré e pós-parto. Portanto, houve quatro tratamentos: suplementação durante pré e pós-parto (PrePost), suplementação durante pré-parto, mas não durante pós-parto (Pré), sem suplementação durante pré-parto, mas durante pós-parto (Pós) e sem suplementação durante pré ou pós- parto (Controle). Durante o pré-parto, as vacas suplementadas apresentaram maior consumo de matéria seca (MS), matéria orgânica (MO) e PB, em comparação com as vacas sem suplementação (P0,10), nem a digestibilidade da fibra em detergente neutro. A suplementação durante o pós-parto mostrou um efeito na ingestão de MS e MO quando expresso em g/kg de PC (P0,10). A suplementação durante pré e/ou pós-parto não afetou (P>0,10) a concentração sérica de glicose, proteínas totais, albumina, globulinas, nitrogênio ureico no sangue (BUN), ácidos graxos não esterificados (NEFA) e β-hidroxibutirato (βHB). Da mesma forma, não houve interação significativa entre tratamentos e tempo em que essas variáveis foram medidas (P>0,10). No entanto, a concentração dessas variáveis mudou significativamente dependendo do dia da amostragem (P0.10), neither digestibility of neutral detergent fiber. Supplementation during post-calving showed an effect on intake of DM and OM when expressed as g/kg of BW (P0.10). Supplementation during pre- and/or post-calving did not affect (P>0.10) serum concentration of glucose, total proteins, albumin, globulins, blood urea nitrogen (BUN), non-esterified fatty acids (NEFA) and β-hydroxybutyrate (βHB). Similarly, there were no significant interaction between treatments and time when these variables were measured (P>0.10). However, the concentration of these variables changed significantly depending of the sampling day (P

BackgroundHeadaches after concussion are common, potentially debilitating, and long lasting. There are currently no guidelines on the treatment of post traumatic headaches (PTH). The aim of this study is to investigate the effects of early prophylactic pharmacologic treatment on the development of chronic post traumatic headaches (cPTH) in adolescent and adult concussion patients.MethodsPatients were retrospectively enrolled from the patient population at the Barrow Concussion and Brain Injury Center (Phoenix, AZ) from the previous 5 years. Males and females ages 13 and older with a diagnosis of PTH attributed to mild head injury based on ICHD2 criteria who were offered a headache prophylactic medication were included. Patients were divided into 3 groups: those who did not take treatment (Untreated), those who took nortriptyline (Nor), and those who took topiramate (Top). Groups were subdivided into those that developed cPTH and those who did not (ncPTH). The average time from injury to start of treatment (SoT) in days were analyzed using t-tests within and between groups.ResultsOne hundred twenty patients met inclusion criteria for the study (Untreated = 36, Top = 46, Nor = 38). Overall, 64 of 120 patients met criteria for cPTH (53%). SoT and development of cPTH is significant overall (35 vs 23, p< 0.001). SoT is significant for Untreated (NcPTH 14.4 vs cPTH 35.6, p = 0.001) and Top (NcPTH 23.9 vs cPTH 35.5, p = 0.002), but not for Nor (NcPTH 31.9 vs cPTH 34.0, p = 0.372). For NcPTH there is a significant difference between SoT for Untreated and Top (14.4 vs 23.9, p = 0.04) and Untreated vs Nor (14.4 vs 31.9, p = 0.002), but not Top and Nor (23.9 vs 31.9, p = 0.09). For cPTH there is no difference for SoT between groups.ConclusionEarly intervention with nonpharmacologic treatments and topiramate is associated with reduced development of cPTH.

Conventional management for concussion involves prescribed rest and progressive return to activity. Recent evidence challenges this notion and suggests that active approaches may be effective for some patients. Previous concussion consensus statements provide limited guidance regarding active treatment.