A Modified Direct Power Control Strategy Allowing the Connection of Three-Phase Inverters to the Grid Through LCL Filters

Abstract — This paper proposes a novel approach to adapt the conventional Direct Power Control (DPC) for high power applications with a third order LCL filter. The strong resonance present in the LCL filter is damped with additional effort in the system control. The application of DPC to the control of threephase Voltage Source Inverter (VSI) connected to the grid through a LCL filter has not yet been considered. An active damping strategy for the LCL filter together with harmonic rejection control is proposed over the conventional DPC. The steady state as well as the dynamic performance of the proposed system is presented by means of the simulation results and compared with the conventional approach

Key factors controlling the post-fire hydrological and erosive response at micro-plot scale in a recently burned Mediterranean forest

The impacts of wildfires on the hydrological and erosive response of forest ecosystems have been extensively studied worldwide. Nevertheless, few studies have measured post-fire runoff and erosion over large time scales in Mediterranean-climate type environments and even fewer studies considered the effects of pre-fire land management practices on post-fire hydrological and erosive processes. In a previous study in the Colmeal study area, Vieira et al. (2016) revealed that post-fire runoff and erosion may not follow the classic window of disturbance model, since the peak of post-fire response occurred in the second and third years after fire. This previous study also showed that pre-fire land management can substantially influence the post-fire response, since annual runoff and erosion were lower in pre-fire unplowed than plowed sites. In this follow-up work, a multiple regression model (MRM) analysis was performed to understand how several key factors influence the hydrological and erosive response of a burned Mediterranean forest, taking into account the wildfire; pre-fire land management practices (unplowed, downslope plowed, and contour plowed) and soil moisture conditions. Based on the results of the present study, post-fire runoff was largely explained by rainfall amounts and soil water repellency (SWR)-related variables, whereas erosion processes were better explained by rainfall intensity and ground cover variables. Fewer factors were found to control the hydrological response of plowed sites when compared to the unplowed site. Aside from rainfall intensity, which was the major factor controlling sediment losses, bare soil cover also seems to have been important for erosion processes at the unplowed site, whereas at the plowed sites stone cover was the second most relevant factor. Rainfall-related variables (rainfall and maximum 30-min rainfall intensity) were more important for explaining runoff and erosion under dry conditions than under wet conditions. The results of the MRM analysis are an important contribution to understand the dynamics of burned forest areas and should be considered when adapting hydrological and erosion models to post-fire environments.publishe

Relative age effect on national selection process in triathlon

El objetivo de este estudio fue analizar el efecto de la edad relativa (RAE) en el proceso de selección nacional de triatletas (n = 1321) durante las temporadas 2013-2015. La muestra fue divida por categorías y sexo. Cada una fue subdividida en 4 cuartiles según la fecha de nacimiento. Las diferencias fueron analizadas mediante la prueba no paramétrica Krustal-Wallis. Para la comparación múltiple se utilizó U de Mann Whitney. Los resultados mostraron que el rendimiento en las pruebas analizadas presentaba una mejor tendencia en aquellos deportistas nacidos en el primer cuartil del año para el sexo masculino. En esta línea, los atletas nacidos en la última parte mostraron un peor rendimiento general. Estos resultados fueron menos consistentes para el sexo femenino. Este trabajo ha puesto de manifiesto la influencia del RAE en los procesos de identificación de talentos y la estructura competitiva, sugiriendo su consideración en los procesos de selecciónThe aim of this study was to analyze the influence of relative age effect on the selection process in triathlon (n = 1321). The sample was divided by category and gender. Each category was allocated into four quartiles - based on date of birth according to the selection year. The Krustal-Wallis and Mann-Whitney test were used to analyze the intra-categorical and intra-gender differences. The results showed a better performance trend in those athletes that were born in the first quartile. In contrast, athletes that were born in the latter part of the year showed poorer overall performance and a lower score in the point scale. However, these results were less consistent for females. This work has shown a significant loss of potential triathlon talent due to the influence of RAE in the selection process and competitive structureEste trabajo ha sido financiado por la Secretaría de Investigación, Desarrollo e Innovación del Ministerio de Economía [DEP2012-32124

Avaliação da fixação biológica de nitrogênio e da colonização micorrízica em dez genótipos de feijão-de-corda em solo de tabuleiros costeiros.

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Simulation-based evaluation of school reopening strategies during COVID-19: a case study of São Paulo, Brazil

During the COVID-19 pandemic, many countries opted for strict public health measures, including closing schools. After some time, they have started relaxing some of those restrictions. To avoid overwhelming health systems, predictions for the number of new COVID-19 cases need to be considered when choosing a school reopening strategy. Using a computer simulation based on a stochastic compartmental model that includes a heterogeneous and dynamic network, we analyze different strategies to reopen schools in the São Paulo Metropolitan Area, including one similar to the official reopening plan. Our model allows us to describe different types of relations between people, each type with a different infectiousness. Based on our simulations and model assumptions, our results indicate that reopening schools with all students at once has a big impact on the number of new COVID-19 cases, which could cause a collapse of the health system. On the other hand, our results also show that a controlled school reopening could possibly avoid the collapse of the health system, depending on how people follow sanitary measures. We estimate that postponing the schools’ return date for after a vaccine becomes available may save tens of thousands of lives just in the São Paulo Metropolitan Area compared to a controlled reopening considering a worst case scenario. We also discuss our model constraints and the uncertainty of its parameters

Avaliação de cultivares de milho precoce em alguns estados do Nordeste brasileiro.

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Sistemas de cultivo para as culturas de milho, feijão (Phaseolus vulgaris L.) e algodão em consórcio, no Estado de Sergipe.

Área de abrangênia, sistema de cultivo n.1 (milho x feijão), preparo do solo, adubação, plantio, época, cultivares, arranjo espacial, espaçamento e densidade do plantio, tratos culturais, tratos fitossanitários, colheita e beneficiamento, armazenamento, coeficientes técnicos, sistema de cultivo n.2, (milho x feijão x algodão) .bitstream/item/43933/1/CPATC-DOCUMENTOS-04-SISTEMAS-DE-CULTIVO-PARA-AS-CULTURAS-DE-MILHO-FEIJAO-E-ALGODAO-EM-CONSORCIO-N.pd

Impacts of climate and land use changes on the hydrological and erosion processes of two contrasting Mediterranean catchments

The impacts of climate and land use changes on streamflow and sediment export were evaluated for a humid (São Lourenço) and a dry (Guadalupe) Mediterranean catchment, using the SWAT model. SWAT was able to produce viable streamflow and sediment export simulations for both catchments, which provided a baseline for investigating climate and land use changes under the A1B and B1 emission scenarios for 2071–2100. Compared to the baseline scenario (1971–2000), climate change scenarios showed a decrease in annual rainfall for both catchments (humid: − 12%; dry: − 8%), together with strong increases in rainfall during winter. Land use changes were derived from a socio-economic storyline in which traditional agriculture is replaced by more profitable land uses (i.e. corn and commercial forestry at the humid site; sunflower at the dry site). Climate change projections showed a decrease in streamflow for both catchments, whereas sediment export decreased only for the São Lourenço catchment. Land use changes resulted in an increase in streamflow, but the erosive response differed between catchments. The combination of climate and land use change scenarios led to a reduction in streamflow for both catchments, suggesting a domain of the climatic response. As for sediments, contrasting results were observed for the humid (A1B: − 29%; B1: − 22%) and dry catchment (A1B: + 222%; B1: + 5%), which is mainly due to differences in the present-day and forecasted vegetation types. The results highlight the importance of climate-induced land-use change impacts, which could be similar to or more severe than the direct impacts of climate change alone

Hormonal contraceptives and the length of their use are not independent risk factors for high-risk HPV infections or high-grade CIN

AIMS: To evaluate the role of hormonal contraceptives as a risk factor of high-risk human papillomavirus (HR-HPV), cervical intraepithelial lesions (CIN) and cervical cancer in our multi-center population-based LAMS (Latin American Screening) study. METHODS: A cohort study with >12,000 women from Brazil and Argentina using logistic regression to analyze the covariates of hormonal contraception (HOC - oral, injections, patches, implants, vaginal ring and progesterone intrauterine system) use followed by multivariate modeling for predictors of HR-HPV and CIN2+. RESULTS: HR-HPV infection was a consistent risk factor of high-grade CIN in all three groups of women. The length of HOC use was not significantly related to high-grade squamous intraepithelial lesions (HSIL)+ Pap (p = 0.069), LSIL+ Pap (p = 0.781) or ASCUS+ (p = 0.231). The same was true with the length of HOC use and histology CIN3+ (p = 0.115) and CIN2+ (p = 0.515). Frequently, HOC users have previously shown more HPV-related lesions, as well as lower HPV prevalence if they were current smokers. But HOC use and time of usage were not independent risk factors of either HR-HPV infection or high-grade CIN using multiple logistic regressions. CONCLUSIONS: No evidence was found for an association between the use of HOC with an increased risk for HR-HPV infection or high-grade CIN in this cohort.This study is a part of the ongoing LAMS (Latin American Screening) study, entitled: Improving Health Systems Towards Equality-Based Control of Cervical Cancer in Latin America, and is supported by the INCO-DEV Program of the European Commission (Project No. ICA4-CT-2001-10013). The generous contribution of Digene Corporation (USA) who donated the HCII tests at our disposal is gratefully acknowledged

Impact of mothers' IPV-PTSD on their capacity to predict their child's emotional comprehension and its relationship to their child's psychopathology

Background: Previous studies demonstrated that when the violence-exposed child becomes a mother and interacts with her own child during early sensitive periods for social-emotional development, she may have difficulties providing sensitive responsiveness to the child's emotional communication. Such difficulties place the child's development of emotional comprehension (EC) and related self-regulation at risk. The aim of this study was to examine how mothers' interpersonal violence-related posttraumatic disorder (IPV-PTSD) would affect their children's EC and their own ability to predict their children's EC. We also investigated how mothers' predictive ability would correlate with child psychopathology. Methods: Sixty-one mother-child dyads (36 with IPV-PTSD) participated in this study. Children's (mean age = 7.0 years, SD = 1.1) EC was assessed with the Test of Emotion Comprehension (child TEC) and their psychopathology as reported by the mother was assessed with the Child Behaviour Checklist (CBCL) and as evaluated by a clinician using selected modules of the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS). Mothers were measured for IPV-PTSD with the Clinician Administered PTSD Scale (CAPS) and for their capacity to predict their child's emotional comprehension (mother-responding-as-child TEC; mTEC). Results: We found no significant between-group differences in children's level of EC. Maternal PTSD was associated with lower scores on the mTEC, however. Reduced maternal scores on the mTEC were significantly associated with maternal report of increased aggressive child behaviour and with depression symptoms on the K-SADS. Further, scores on the mTEC interacted with maternal report of child aggression on child oppositional defiant disorder (ODD) symptoms on the K-SADS. Conclusion: These findings support that improving maternal emotional comprehension may help reduce child risk for psychiatric morbidity in this population