Publicações

 In this paper we analyze electric-field and current measurements of upward leaders induced by a downward negative lightning flash that struck a residential building. The attachment process was recorded by two high-speed cameras running at 37,800 and 70,000 images per second and the current measured in two lightning rods. Differently from previous works, here we show, for the first time, current measurements of multiple upward leaders that after initiation propagate to connect the negative downward moving leader. At the beginning of the propagation of the leaders that initiate on the instrumented lightning rods, current pulses appear superimposed to a steadily increasing DC current. The upward leader current pulses increase with the approach of the downward leader and are not synchronized but present an alternating pattern. All 2D leader speeds are approximately constant. The upward leaders are slower than the downward leader speed. The average time interval between current pulses in upward leaders is close to the interstep time interval found by optical or electric field sensors for negative cloud-to-ground stepped leaders. The upward leaders respond to different downward propagating branches and, as the branches alternate in propagation and intensity, so do the leaders accordingly. Right before the attachment process the alternating pattern of the leaders ceases, all downward leader branches intensify, and consequently upward leaders synchronize and pulse together. The average linear densities for upward leaders (49 and 82 mu C/m) were obtained for the first time for natural lightning. Plain Language Summary The effectiveness of a lightning protection system depends on its efficiency to intercept the down coming leader of a cloud-to-ground lightning flash. The interception is usually done by an upward connecting leader that initiates from grounded structures, humans, or living beings that protrude from nearby ground. The understanding of the upward connecting leader and of the attachment process with the downward leader plays an important role in the determination of the zone of protection and therefore in the improvement of a lightning protection system. Unconnected upward leaders, that is, upward leaders that fail to connect the downward leader, are also of great importance in lightning protection. They can be large enough to cause damage to equipment vulnerable to sparks or induced currents, and enough to injure people from who it initiates. In this paper we analyze electric-field, speed, and current measurements of upward leaders induced by a downward negative lightning flash that struck a residential building. The attachment process was simultaneously recorded by two high-speed cameras, an electric-field sensor, and current sensors installed on two lightning rods. Differently from previous works we show, for the first time, current measurements of multiple upward leaders induced by the negative downward moving leader.

Este trabalho tem por objetivo identificar as desigualdades do acesso domiciliar à rede de abastecimento de água e de esgotamento sanitário na Região Metropolitana do Rio de Janeiro, RJ, Brasil. Com dados do Censo Demográfico (2010) e de Uso e Cobertura do Solo, um método dasimétrico desagregou os dados censitários, considerando um espaço celular. A dependência espacial do acesso foi estudada por análise espacial exploratória dos Índices de Moran Global e Local. Os resultados indicaram dependência espacial de acesso ao abastecimento de água e esgotamento sanitário e clusters (Alto-Alto) para os dois tipos de serviços sobretudo na capital, Rio de Janeiro, e municípios limítrofes a oeste, além dos municípios Niterói e São Gonçalo, a leste. Esta análise das desigualdades espaciais contribui para o planejamento e adequação de políticas de saneamento.

Species distribution models (SDMs) are one of the most widely used tools to predict areas with potential for occurrence of native, invasive and endangered species, based on current and future environmenal and climate conditions. Despite their global use, evaluating the accuracy of SDMs based only on presence records is still a challenge. The performance of models depends on the sample size and species prevalence. Recently, studies to model the distribution of species in the Caatinga biome in Northeast Brazil have gained force, raising the question about the minimum number of presence records adjusted to different prevalences that are necessary to generate accurate SDMs. In this context, the objective of this study was to indicate minimum numbers of presence records for species with different prevalences in the Caatinga biome to obtain accurate SDMs. For that purpose, we used a method involving simulated species and performed repeated evaluations of the models performance in function of the sample size and prevalence. The results indicated that for this approach in the Caatinga biome, the minimum required numbers of specimen records were 17 and 30 for species with narrow and widespread distributions, respectively.

Desde o século XVIII o Rio de Janeiro é afetado por eventos extremos de precipitação, os quais acarretam uma série de transtornos no espaço urbano, por meio de inundações e movimentos de massa. Dentre inúmeros eventos, o ocorrido no dia quatorze de fevereiro de 2018, possui características peculiares, uma vez que precipitou 51 mm em 1h. Dessa forma, objetivou-se, através da análise rítmica, compreender o evento de maneira dinâmica, dando atenção aos impactos causados na bacia do rio Piraquê-Cabuçu, no município do Rio de Janeiro. Para tal, foram levantados dados para a caracterização da gênese do fenômeno, buscando individualizar os tipos de tempo atmosféricos, através do acompanhamento de seus ritmos. Para a consecução do objetivo, no que tange ao arcabouço metodológico, o estudo recorreu a dados meteorológicos e maregráficos, imagens de satélite, radar meteorológico, cartas sinóticas, dados de reanálise e o Diagrama de Skew-T Log P, além de dados hemerográficos. Com tudo, muito provavelmente o episódio de inundação esteve associado à ocorrência de um evento de downburst, pois os dados corroboram a existência de uma amálgama de condicionantes meteorológicos característicos de tais processos: perda de sustentação e consequente movimento descente de uma parcela de cumulonimbus, o total pluviométrico concentrado e os elevados índices de instabilidade, como o valor de 1.198 J/kg para o índice CAPE. Dadas características genéticas do evento, além do alto grau de antropização da bacia, como consequência os impactos afetaram cerca de 50.000 pessoas e provocaram repercussões na área de estudo por, pelo menos, 7 dias.

O Brasil muitas vezes é caracterizado pela abundância de água, entretanto eventos recorrentes de escassez hídrica nas diversas regiões do País e os múltiplos impactos que podem ser desencadeados e intensificados pelo processo de mudanças climáticas, demonstram a importância da gestão contínua desse recurso. Uma região que tem sido considerada uma alternativa para garantir as demandas hídricas de importantes centros para o desenvolvimento do País, tanto internos como externos as suas fronteiras, é a Bacia do Paraíba do Sul (BPS). Considerando a importância da transposição da BPS para a bacia do Guandú para o atendimento das demandas hídricas e energéticas da região metropolitana do Rio de Janeiro, o presente trabalho tem como objetivo a análise da variabilidade futura dos recursos hídricos, tendo como principal foco a transposição para a bacia do Guandú, e a variabilidade da geração de energia BPS, considerando o processo de mudanças climáticas. A comparação das projeções das vazões e quantidade de energia gerada em cenários futuros com o cenário de referência, mostram uma elevada influência dos processos climáticos nas variações da disponibilidade hídrica da bacia, além de uma tendência geral de redução da disponibilidade hídrica, principalmente nos cenários de maiores emissões de gases do efeito estufa.

Cities are increasingly vulnerable to climate change’s impacts and poorly adapted to extreme variability. This study aimed to evaluate climate projections of air temperature and precipitation in seven cities in the Metropolitan Region of São Paulo that correspond to the Greater ABC Paulista. We used high-resolution models Eta-HADGEM2_ES (CMIP5), CNRM-CM6-1-HR (CMIP6), and the TerraClimate database to analyze future projections and the specific warming levels (SWLs), respectively. Model data were validated with observed data and bias was removed. A bias correction factor was generated and used in the climate projections for the different emission scenarios. The results show a consensus between the models and the SWLs (2 and 4°C) for the increase in maximum (Tmax) and minimum (Tmin) temperatures for all municipalities in ABC Paulista in different emission scenarios until the end of the 21st century. For the nearest future (20202040), the city of São Caetano do Sul (SCS) shows the highest positive annual anomalies of Tmax concerning the climatological period (19852015), for the scenario RCP4.5 (2.8°C) and the RCP8.5 (7.4°C), according to projections from the Eta-HADGEM2_ES, highlighting summer and autumn as the hottest. For precipitation, there was a consensus between the Eta-HADGEM2_ES and the CNRM-CM6-1-HR for a reduction in all scenarios and time-slices 20202040 and 20412070. The municipalities of Diadema (−78.4%) and SCS (−78%) showed the most significant reductions in December for the RCP8.5, and for SSP5-8.5, SCS shows −30.9% in December for the 20202040 time-slice. On the other hand, TerraClimate presents excess rain for Ribeirão Pires (+24.8%) and Santo André (+23.7%) in winter for SWL4°C. These results suggest that an increase in Tmax and Tmin, as projected, should influence the intensity of extreme heat events. Furthermore, a reduction in annual and seasonal rainfall does not mean a decrease in the region’s extreme daily events that cause floods and landslides. However, it leaves an alert of water scarcity for the supply and demand of the population. ABC Paulista does not have adaptation plans to face extreme climate change. The results can contribute to the first phase of creating an adaptation plan, giving a first view of the climate threat that should intensify until the end of the twentieth century affecting the most vulnerable municipalities.

The western tropical North Atlantic (WTNA) is a very complex region, with the influence of intense western boundary currents in connection with equatorial zonal currents, important atmospheric forcings (e.g Intertropical Convergence Zone), mesoscale activities (e.g NBC rings), and the worlds largest river discharge as the Amazon River runoff. The volume discharge is equivalent to more than one-third of the Atlantic river freshwater input, with a plume that spreads over the region reaching the northwestward Caribbean Sea and eastward longitudes of 30°W, and influencing from physical to biological structures. Therefore, in order to enable and encourage more understanding of the region, here we present a dataset based on an idealized scenario of no river runoff of the Amazon River and Par ́a River in the WTNA. The numerical simulations were conducted with a regional oceanic modeling system (ROMS) model and three pairs of files were generated with the model outputs: (i) ROMS-files, with the parameters of the ROMS-outputs raw data in a NetCDF format and monthly and weekly frequencies; (ii) MATLAB-files, which contain oceanographic parameters also in monthly and weekly frequencies; and (iii) NetCDF-files, with oceanographic parameters again in monthly and weekly frequencies. For each file, we present the coordinates and variable names, descriptions, and correspondent units.

Computational analysis of electroencephalographic (EEG) signals have shown promising results in detecting brain disorders, such as Alzheimer’s disease (AD). AD is a progressive neurological illness that causes neuron cells degeneration, resulting in cognitive impairment. While there is no cure for AD, early diagnosis is critical to improving the quality of life of affected individuals. Here, we apply six computational time-series analysis methods (wavelet coherence, fractal dimension, quadratic entropy, wavelet energy, quantile graphs and visibility graphs) to EEG records from 160 AD patients and 24 healthy controls. Results from raw and wavelet-filtered (alpha, beta, theta and delta bands) EEG signals show that some of the time-series analysis methods tested here, such as wavelet coherence and quantile graphs, can robustly discriminate between AD patients from elderly healthy subjects. They represent a promising non-invasive and low-cost approach to the AD detection in elderly patients.

This paper introduces the gtfs2emis model, a bottom-up method available as an R package to estimate emissions of public transport systems. The method uses General Transit Feed Specification (GTFS) data, a standard format for public transport data widely adopted worldwide, which makes the method easily applicable to cities with limited data. The model requires a GTFS feed of a given transport system and a table with general characteristics of the vehicle fleet profile. The package can estimate over 16 pollutants and energy consumption based on emission factor models from Europe, the United States, and Brazil. It also includes functions to help users examine how emissions are distributed across space, at different times of the day, and by types of vehicles. This paper presents a reproducible example of the city of S ao Paulo (Brazil) to demonstrate the gtfs2emis package and to discuss the potential applications and limitations of the proposed model.

over the past few decades, a significant amount of agricultural land has been lost due to soil degradation/desertification. in addition, the increasing frequency of extreme events, such as intense droughts and forest fires, has negatively impacted various ecosystem services. two of the main brazilian biomes-the cerrado and the caatinga-have been affected by increased rainfall variability, leading to desertification, increased fire frequency, and, consequently, rising concerns regarding the water and food security of the local population. in this study, we develop a methodology to assess these impacts using a socio-environmental vulnerability index (sevi) that combines physical, environmental, and socio-economic indicators related to exposure, sensitivity, and adaptation, as well as including socio-environmental feedback. the developed sevi is then applied to the sao francisco and parnaiba river basins. the proposed index is based on the medalus methodology and is adapted to include multiple biological, physical, and socio-economic indicators, allowing for the discrimination of areas characterized by different levels of vulnerability. we also analyze the effectiveness of governmental policies, such as the creation of conservation areas and the rural registration of properties, in reducing vulnerability. the sevi analysis highlights that adaptive capacity is the main constraint for reducing socio-environmental vulnerability in the parnaiba basin, while exposure and sensitivity are the greater challenges in the sao francisco basin. the results of this study are crucial for the prioritization of recovery actions in degraded areas.

The joint effects of climate change and landscape fragmentation to the genetic viability of isolated populations has barely been addressed for the Atlantic Forest fauna. Therefore, this work explored the potential habitat suitability for the southern muriqui (Brachyteles arachnoides), by modeling climate change, landscape fragmentation, and genetic diversity loss of the species. Maxent was used to model its potential distribution in 2050, with two climate change scenarios. A land use and land cover change model was applied to describe current and future forest fragmentation patterns, and a Population and Habitat Viability Analysis (PHVA) was used to describe the retention of genetic diversity of the southern muriqui. Although PHVA modeling provided a low risk of extinction of the southern muriqui, climate change and fragmentation could result in the loss of >65% of the suitable forest patches, and reduce the habitat suitability to only 11% of the potential distribution area, which could lead to future genetic diversity loss and decreased capacity of self-sustained populations. In both climate change scenarios, the suitable areas for the southern muriqui in Paraná and Rio de Janeiro states will decrease more drastically. Areas where the primate occurs in the interior of São Paulo and Rio de Janeiro states will disappear or be climatically disconnected from the core potential habitat. Alike preventing further deforestation, Atlantic Forest restoration actions are needed to connect the viable populations for compensating the projected land use and climate change impacts to the long term persistence of the southern muriqui.

Nitrogen pollution is one of the most widespread and challenging problems in Brazil, being the cause of several environmental and health issues. The focus of this thesis is to investigate the underlying drivers of reactive nitrogen emissions, the sustainability of nitrogen use, and the policy responses to address the pollution problem, with the aim of contributing to improving nitrogen management in the country. To accomplish this main objective, we carried out the following activities, in which specific methods were applied for each one of them, and unique but also complementary results were obtained: (i) development of a Conceptual Framework Model to understand the complexity of N dynamics in the country, the diversity of drivers, and potential damage to environment and human health; (ii) calculation of the level of nitrogen sustainability using the Entropy Weight Method (EWM) on a set of N-related indicators, within the environmental, economic, social, and institutional subsystems, and (iii) application of the Policy Coherence Analytical Framework to show how coherent interactions are among N-related policies in Brazil and how these policies can promote the development of a potential integrated nitrogen policy approach. As an overall result, we conclude that the driving forces behind the increase in N emissions are the productive activities aimed at meeting the demand for food, energy, and housing by a rapidly growing population, leading to a weak-to-basic level of sustainability of nitrogen management in the country. Our results also indicate that political and institutional factors (e.g., good governance, regulatory quality, and political stability) are essential to prepare and implement successful responses to address the problem of nitrogen pollution in Brazil. Finally, the policy coherence analysis shows a favorable outcome, since most of the analyzed policies present positive interactions, which enables and reinforces the achievement of their objectives. An exception is the 2022 National Fertilizer Plan, considering that the absence of environmental care actions could make several other policies unfeasible. In this case, we suggest reformulating the plan with the involvement of multiple actors and stakeholders, to include environmental issues related to fertilizer production and use, as well as to avoid counteraction with other N-related policies.