Abstract This work presents an adaptive hybrid signal precoding strategy for Cell-Free (CF) Massive multiple-input multiple-output (MIMO) systems. The proposed solution exploits the advantages of both distributed and centralized signal processing schemes to perform precoding. In our proposal, some access points (APs) are dynamically configured to be used in a centralized precoding scheme, whereas others are adjusted to employ a distributed method. Simulation results show that it is possible to achieve a good compromise between spectral efficiency (SE) and computational complexity (CC) in CF Massive MIMO systems finding a sensible balance between APs utilized in centralized and distributed precoding. To the best of our knowledge, prior-art solutions have not addressed an adaptive hybrid precoding method itself, they have only proposed a specific solution for each architecture, i.e., distributed or centralized.

Abstract The aim of this study was to verify whether obesity and acute physical exercise could influence the reactivity to mental stress. Twelve normal weight (NW) and ten obese (Ob) (31.82% women), normotensive individuals between 18 and 40 years old were evaluated. The Stroop color test was performed under two conditions: 1) Baseline and 2) 30 min after the end of aerobic physical exercise. Individuals performed 30 min of physical exercise (NW: 3.38 and Ob: 2.99 km·h-1; p< 0.05) between 50-60% of heart rate reserve (NW: 139±7 and Ob: 143±7 bpm). The reactivity to mental stress for systolic blood pressure - SBP (Δ2 min) and diastolic blood pressure - DBP (Δ2 and Δ4 min) was lower (p< 0.05) in Ob compared to NW group. The SBP reactivity to mental stress was less (p< 0.05) post-exercise in all moments (Δ2 and Δ4 min), regardless of obesity, while the DBP reactivity to mental stress was less post-exercise, only in NW. BP reactivity to stress correlated negatively with obesity indicators (r/Rho = - 0.42 to - 0.64), under the baseline condition, but not post-physical exercise. Obesity blunted BP reactivity to mental stress in normotensive young adults. Moderately-intensity acute aerobic exercise reduced SBP reactivity to mental stress, regardless of obesity, while it reduced DBP reactivity to mental stress, only in NW. In summary, acute physical exercise may be a one means to prevent cardiovascular changes.

Resumo O objetivo deste estudo foi verificar se a obesidade e o exercício físico agudo podem influenciar a reatividade ao estresse mental. Foram avaliados 12 indivíduos eutróficos (E) e dez obesos (Ob) (31,82% mulheres), normotensos entre 18 e 40 anos. O teste de cor Stroop foi realizado em duas condições: 1) Linha de base e 2) 30 min após o término do exercício físico aeróbio. Os indivíduos realizaram 30 min de exercício físico (E: 3,38 e Ob: 2,99 km•h-1; p<0,05) entre 50-60% da frequência cardíaca de reserva (E 139±7 e Ob: 143±7 bpm). A reatividade ao estresse mental para pressão arterial sistólica - PAS (Δ2 min) e pressão arterial diastólica - PAD (Δ2 e Δ4 min) foi menor (p< 0,05) no grupo Ob comparado ao grupo E. A reatividade da PAS ao estresse mental foi menor (p< 0,05) pós-exercício em todos os momentos (Δ2 e Δ4 min), independente da obesidade, enquanto a reatividade da PAD ao estresse mental foi menor pós-exercício, apenas no E. A reatividade da PA ao estresse correlacionou-se negativamente com os indicadores de obesidade (r/Rho = - 0,42 a - 0,64), na condição basal, mas não pós-exercício físico. A obesidade embotou a reatividade da PA ao estresse mental em adultos jovens normotensos. O exercício aeróbico agudo de ientesidade moderada reduziu a reatividade da PAS ao estresse mental, independentemente da obesidade, enquanto reduziu a reatividade da PAD ao estresse mental, apenas no E. Em resumo, o exercício físico agudo pode ser um meio de prevenir alterações cardiovasculares.

Abstract The characterization of unsaturated soils using hydromechanical methods is an essential requirement in soil science. However, current laboratory techniques used to obtain soil water retention and unsaturated hydraulic conductivity curves are time-consuming. To address this issue, a method based on indirect measures (electrical resistivity/electrical conductivity) was developed to quantitatively characterize soils. A novel unsaturated semi-empirical hydrogeophysical model of soils was developed by incorporating the hydrodynamic, geophysical, and petrophysical characteristics of soils. The model assumes that the parameters influencing the variation in the volumetric water content with matric suction and electrical resistivity are the same. The electrical resistivity characteristic curve (ERCC) defines a function that correlates environmental variables, electrical resistivity, soil water status, matric suction, hydraulic and petrophysical parameters, and fluid electrical resistivity. Model validation confirmed that the proposed approach can estimate the soil water retention curve (SWRC) via the indirect measures, and the results agreed with the experimental data. This indicates that it is possible to determine the SWRC and unsaturated hydraulic conductivity function of soil using the described approach.

Abstract Predicting the pile’s load capacity is one of the first steps of foundation engineering design. In geotechnical engineering, there are different ways of predicting soil resistance, which is one of the main parameters. The pile load test is the most accurate method to predict bearing capacity in foundations, as it is the most accurate due to the nature of the experiment. On the other hand, it is an expensive test, and time-consuming. Over the years, semi-empirical methods have played an important role in this matter. Initially, many proposed methods were based on linear regressions. Those are still mainly used, but recently the use of a new method has gained popularity in Geotechnics: Artificial Neural Network. Over the past few decades, Machine Learning has proven to be a very promising technique in the field, due to the complexity and variability of material and properties of soils. Considering that, this work has reviewed and mapped the literature of the main papers published in journals over the last decades. The aim of this paper was to determine the main methods used and lacks that can be fulfilled in future research. Among the results, the bibliometric and protocol aiming questions such as types of piles, tests, statistic methods, and characteristics inherent to the data, indicated a lack of works in helical piles and instrumented pile load tests results, dividing point and shaft resistance. s design resistance parameters foundations experiment hand timeconsuming. timeconsuming time consuming. consuming time-consuming years semiempirical semi empirical matter Initially regressions Geotechnics Network decades field soils research results data

Abstract This paper provides preliminary results on geothermal energy piles (GEPs) for the thermal climatization of structures founded on the typical tropical unsaturated soil of the central region of Brazil. The research employed a series of prototype simulations of a thermal pile embedded into a calibration chamber with compacted unsaturated soil. It closely simulates the behavior of a (prototype) section from real scale GEPs founded in the geotechnical media of the region, in terms of compactness, mineralogy, water content and thermal variables. One of the on-going thermal tests was numerically simulated with a Multiphysics commercial software to calibrate a model and expand the results to possible scenarios of distinct (laboratory) GEP performance. The analyses will base future simulations of typical foundation layouts for large-scale structures founded on tropical soils of the region to verify the thermal energy efficiency under average operational conditions. Besides the known limitations of this research, still at early stage, an initial assessment was achieved to design shallow geothermal systems for local conditions.

Abstract This paper explores the potential of machine learning techniques to predict the soil water retention curve based on physical characterization parameters. Results from 794 water retention and suction points obtained from 51 different soils were used in the algorithm. The soil properties used are the percentages of gravel, sand, silt, and clay, the plasticity index, the porosity, and the relation between the volumetric water content and total suction. The data were used as input for machine learning estimators to predict the volumetric water content of a soil with specified physical characterization parameters and suction, the techniques of artificial intelligence were developed in python. Results show that an extremely randomized trees' estimator can reach a coefficient of determination of 0.99 in the training dataset, with a coefficient of 0.90 in the cross-validation and testing dataset, which measures the generalization capacity. Furthermore, a continuous function can be obtained by fitting a model such as Cavalcante & Zornberg, or van Genuchten, or Costa & Cavalcante (bimodal) to the predictions of the machine learning for use in numerical methods. These results indicate that the proposed machine learning estimator can become an interesting alternative to estimate the soil water retention curve in engineering practice. This work is in progress and the predictions can be improved with the addition of new data. Know how to participate at the end of the paper.

Abstract Mining is an important economic activity in the modern world. However, despite the generated benefits, mining produces tremendous volumes of tailings, an environmental liability with numerous adverse effects. Researches about contaminant transport in tailings dam are important to assess the degree of contamination and to propose preventive or remedial measures. In geotechnical practice, the flow of solutes is generally characterized by numerical solution of the Richards equation to describe water movement followed by advection-dispersion equation to describe contaminant movement. This study aimed to model and simulate contaminant transport in a laboratory column test, using a new analytical formulation and mathematical codes, through tailings in transient unsaturated conditions. The analytical solution for the Richards equation was used to simulate the variation in the volumetric water content and to determine the transient contaminant plume using the advection-dispersion equation subsequently. The models were used to calibrate experimental data from hydraulic characterization and contamination tests. Finally, the normalized contaminant plume (cw/c0) was simulated as a function of time and space. Comparisons with experimental data showed that the analytical formulations adequately expressed the process of contaminant infiltration through the unsaturated porous medium. The formulations offered effectively and are configured as a new approach to solve various contamination problems in transient unsaturated conditions, providing insights into many complex processes that occur in the lab tests and requires far less computational effort compared with current programs to modeling the solute transport using numerical solutions, as the versatile commercial Software HYDRUS.

Abstract Allying technology, theory and engineering practice is one of the main challenges of modern foundation engineering. Current foundation and retaining walls designs may lead to oversizing or undersizing due to the spatial variability of the stratigraphic profile. As the design procedure of piled foundations involves defining the setting depth of the tip, sometimes the piles may not behave as expected, as the soil mass may change significantly even in a small region. In this paper, a study was conducted on the geoenergetic behavior of the soil mass and of the piles of a construction site located in Brasília, DF, Brazil. Previous studies showed that the energy needed to drill a continuous flight auger pile (CFAP) can be related to the strength of the drilled strata. Therefore, a methodological framework was built to further discuss how the geomechanical behavior of CFAPs foundations could be assessed by analyzing the energy needed to drill such piles. Statistical methods, in special the Bootstrap method, were used to assess the possible influences of construction procedures on pile behavior. It was studied how the execution energies of piles vary with initial depth and relative position in the terrain, as well as the influences that they suffer because of the order of execution within a same foundation group and due to the proximity to surrounding retaining walls. The proposed methodology can be used to improve the energy control procedure and performance evaluation of CFAPs, allowing a complementary reliability assessment for the foundation and retaining walls designs and implementations.

Abstract Several regions in Brazil and the world suffer from the presence of collapsible soils. The development of theories for understanding the phenomenon is significant because the increase of water content is associated with several reasons (e.g., precipitation, rupture of sewage, and water systems). Although some theories explain the behavior of various types of soils, they fail to explain collapsible and structured soils. In this research, an alternative interpretation of the consolidation theory is verified and calibrated for collapsible soil. The alternative model was applied to experimental data from a latosol from southeastern Brazil, and comparisons with the classical theory showed a difference in the saturated hydraulic conductivity of around 100 times. The observation showed promising results compared with the saturated hydraulic conductivity of the field (Guelph Permeameter). Furthermore, consolidation tests verified the collapse potential, the variation of consolidation coefficient and saturated hydraulic conductivity, and the total settlement prevision due to the presence of bleach and washing powder.

Abstract Mudflow is often associated with seismic activities. The present study applied a seismic based detection of the surface waves generated by the mudflow of Brumadinho dam collapse using records of Brazilian Seismographic Network. The signal envelope and time-frequency spectrograms of the mudflow signals were used in the analysis. As a result, the mudflow signals were successfully detected from the data recorded at a nearby seismic station. The findings of this study provide a good basis for future research to develop a flood early warning system based on cost-effective, remote and contentious seismic monitoring approaches.

RESUMO A implementação da Política Nacional de Resíduos Sólidos (Lei nº 12.305, de 2 de agosto de 2010) foi um marco para a disposição final e o tratamento de resíduos sólidos no país. A contaminação decorrente da negligência na disposição dos resíduos sólidos urbanos atinge sistemas naturais vitais para a existência humana. Torna-se, portanto, fundamental compreender os mecanismos que estão envolvidos no transporte de contaminantes e os dispositivos geotécnicos para mitigar e/ou remediar os impactos. Neste trabalho, é apresentada a utilização de modelagens matemáticas aplicadas aos resultados dos experimentos realizado por Ritter, em 1998, para determinar o transporte dos principais íons inorgânicos, encontrados no lixiviado do aterro Jardim Gramacho (K+, Cl-, Na+ e NH4 +), por difusão química e sorção. O Aterro de Resíduos Urbanos de Jardim Gramacho está localizado em Duque de Caxias, no estado do Rio de Janeiro, e operou por mais de 30 anos, de 1978 a 2012. Para a compreensão dos mecanismos de transporte, foi utilizada uma solução semi-analítica denominada de camada contaminada equivalente (CCE), proposta por Paz, em 2015, com o objetivo de traçar, no tempo e no espaço, o comportamento desses contaminantes ao longo da amostra de solo utilizada. A vantagem da utilização dessa solução analítica é que ela atende com maior rigor as condições de contorno dos experimentos analisados, quando comparadas com as soluções disponíveis na literatura. Os resultados mostram que os coeficientes de difusão efetivo determinados pela solução CCE apresentam-se dentro dos intervalos indicados na literatura.

ABSTRACT The implementation of the National Solid Waste Policy (Law No. 12.305, of August 2, 2010) was a milestone for the final disposal and treatment of solid waste in the country. The contamination due to negligence in the disposal of urban solid waste reaches natural resources and systems vital to human existence. It is, therefore, essential to understand the mechanisms involved in the transport of contaminants and the best geotechnical devices to mitigate and/or remediate impacts. This paper presents the use of mathematical models applied to the results of the experiments carried out by Ritter, in 1998, to determine the transport of the main inorganic ions found in the leachate of Jardim Gramacho landfill (K+, Cl-, Na+, and NH4 +), by chemical diffusion and sorption mechanisms. The Jardim Gramacho Urban Waste Landfill was located in Duque de Caxias, state of Rio de Janeiro, and operated for more than 30 years, from 1978 to 2012. In order to understand these transport mechanisms, a semi-analytical solution, denominated Equivalent Contaminated Layer (ECL) proposed by Paz, in 2015, was used to trace, in time and space, the behavior of these contaminants along the soil sample used. The advantage of using this analytical solution is that it meets more accurately the boundary conditions of the analyzed experiments, when compared with the solutions available in the literature. The results show that the effective diffusion coefficients determined by the ECL solution are within the ranges indicated in the literature.

Resumo A questão habitacional no Brasil vem sendo tratada de forma isolada. No entanto, deve ser compreendida como questão social e analisada na totalidade. A função social da propriedade enquanto conquista histórica pode ser utilizada visando ao enfrentamento dessa pauta. Entretanto, assiste-se nas cidades ao agravamento desse contexto. Nesse sentido, é trazido um breve apontamento sobre os dados recentes do déficit habitacional e seus determinantes sociais, assim como um registro dos chamados vazios urbanos e sua relação com o processo de especulação imobiliária nas cidades brasileiras, entendendo, dessa forma, como a retenção de terra urbana vem sendo abordada no país. O presente artigo pretende reunir aspectos que problematizem a função social da propriedade e o acesso aos direitos e às políticas públicas habitacionais no cenário brasileiro, bem como analisar o IPTU progressivo, entendendo-o como uma opção para além da função fiscal nas cidades e como um instrumento do direito urbanístico na efetivação de direitos, de gestão da cidade e do uso e da ocupação do solo urbano.

Abstract The housing issue in Brazil has been treated as an isolated problem. However, it must be understood as a social question, and analyzed in its totality. The social function of property as a historical achievement can be implemented to face this agenda. However, we’ve been witnessing the aggravation of this problem in the cities. Thus, we discuss an appointment about the recent data of the housing inequality and its social determinants, understanding how the urban land retention is being addressed in Brazil. This article intends to assemble aspects that problematize both the social function of the property, and the access to the rights and public housing policies in Brazil. We also aim to analyze Timing-Progressive Property Tax, which is not only understood as an option beyond the cities taxing function but also as an instrument of Urban Law in rights attainment, of city management and use and occupation of urban land.

Psychotria viridis is one of the species that produces N,N-dimethyltryptamine. Its decoction together with other species, such as Banisteriopsis caapi, produces ayahuasca, a beverage used for ritualistic and medicinal purposes. The goal of this study was to understand how environmental factors and cultivation methods influenced the content of N,N-dimethyltryptamine in P. viridis. Over all four seasons, leaf samples were collected from 25 different locations in 14 Brazilian states, and Federal District. Environmental parameters, micro and macronutrients, plant characteristics, information on farming methods were correlated with N,N-dimethyltryptamine content, determined by gas chromatography coupled to mass spectrometry (GC-MS). Greatest effects on the N,N-dimethyltryptamine amount were associated with seasonality, altitude, latitude and biome type. A positive correlation between N and Mg content and N,N-dimethyltryptamine levels was statistically established. By regression analysis, the adequate foliar nutrient levels that would result in the concentration of N,N-dimethyltryptamine in cultivated plants similar to that of Amazonian P. viridis were equated.

Resumen En este artículo se describe una metodología basada en el método de estimación puntual de Rosenblueth para el análisis del empuje activo desarrollado en un muro de retención con relleno cohesivo-friccionante bajo condiciones de carga sísmica. El principio básico de esta metodología es usar dos estimaciones puntales, i.e., la desviación estándar y el valor medio, para examinar una variable en el análisis de seguridad. Es posible mostrar que aumentando el valor del coeficiente de aceleración sísmica horizontal, el factor de seguridad por volteo decrece y la probabilidad de falla aumenta, especialmente para coeficientes mayores que 0.2. Por otro lado, es observado que el valor medio del factor de seguridad crece cuando aumenta el coeficiente de aceleración sísmica vertical, sin embargo la probabilidad de falla se mantiene prácticamente igual para el valor del factor de seguridad considerado como crítico (1.15).

Abstract This paper describes a methodology based on the Rosenblueth point estimate method to analyze the active earth pressure developed on retaining walls for c-φ soil backfill under seismic loading conditions. The fundamentals of this methodology are to use two point estimates to examine a variable in the safety analysis: the mean value and the standard deviation. When the horizontal seismic acceleration coefficient increases, the overturning factor of safety decreases, whereas the probability of failure increases, particularly for coefficients greater than 0.2. In addition, the mean factor of safety increases when the vertical seismic acceleration coefficient increases, but the probability of failure remains practically identical for the considered critical factor of safety (1.15).

A queda é uma das consequências mais graves do envelhecimento, sendo reconhecida como importante problema de saúde pública. A pesquisa teve como objetivo investigar aspectos relacionados à ocorrência de quedas em idosos. Participaram do estudo 50 idosos, do bairro Cidade 2000, em Fortaleza-CE, sendo 64% do gênero feminino. Para a coleta de dados foi utilizado um questionário. Observou-se que 42% dos idosos apresentaram, no mínimo, um episódio de queda nos últimos dois anos, dos quais 19% se encontravam entre 60 e 69 anos, 24% entre 70 e 79 anos e 57% entre 80 e 89 anos. As causas foram principalmente relacionadas ao ambiente doméstico inadequado (57%). Dentre os fatores relacionados ao ambiente doméstico que favorecem as quedas, o mais citado foi a existência de superfícies escorregadias (33%). A maioria dos participantes (80%) fazia uso de algum tipo de medicação prescrita por médicos, sendo os anti-hipertensivos utilizados por 42% do grupo. A consequência mais comum das quedas foi a fratura, indicada por 43% dos idosos, tendo sido mais frequente a fratura de rádio (56%). Outras consequências citadas foram trauma craniano (19%), depressão (19%) e ansiedade (19%). Necessitaram de internação hospitalar 33% dos idosos vítimas de quedas. A pesquisa aponta que 60% do grupo praticam atividade física regular e, dentre os sedentários, encontravam-se 90% dos idosos que haviam sido acometidos por quedas. Conclui-se que as quedas podem ser entendidas como eventos que podem, em parte, ser evitados através da adoção de programas e medidas preventivas simples.

Fall is one of the most serious consequences of aging, being recognized as an important public health problem. The research aimed to investigate aspects related to occurrence of falls in older adults. Fifty elderly residents of the neighborhood Cidade 2000, in Fortaleza, Ceará state, participated in the study, 64% were female. For data collection a questionnaire was used. It was observed that 42% of seniors had at least one fall in the last two years, 19% of these were between 60 and 69 years, 24% between 70 and 79 years and 57% between 80 and 89 years. The causes were mainly related to inadequate home environment (57%). Among the factors related to the domestic environment, the most often cited was the existence of slippery surfaces (33%). Most participants (80%) used some type of medication prescribed by doctors, and antihypertensive drugs were used by 42% of the group. The most common consequence of falls was the fracture, indicated by 43% of elderly the radius fracture was the most frequent (56%). Other consequences mentioned were head trauma (19%), depression (19%) and anxiety (19%); 33% of elderly victims of falls required hospitalization. The survey found that 60% of the group reported regular physical activity and 90% of elderly people who had falls were sedentary. We conclude that falls can be understood as events that may in part be avoided by adopting simple preventive measures and programs.