Foraging behavior of fire ant Solenopsis saevissima (Smith) (Hymenoptera: Formicidae) in Felis catus Linnaeus (Carnivora: Felidae) carcass

Solenopsis saevissima fire ants were found foraging in a Felis catus carcass over tissues an secretions present in holes and mucosa. The ants built a dirt-made physical structure around the carcass, which prevented necrophagous flies from laying eggs or larvae in the body. These observations are relevant to increasing knowledge on the role of this ant genus in the decaying process of other animal corpses, including humans

Desenvolvimento em VHDL da camada física de um transmissor 4G

The LTE and LTE-Advanced technologies are standards to the fourth mobile generation, or 4G. The planned successor of this mobile generation is 5G, which will be based on 5G-New Radio (5G-NR) standard. The 5G technology is on an initial phase of deployment. One of its features that are essential in this initial phase is the support for 4G communications, because many of the mobile devices currently in use do not have support for 5G communications. This support is made possible if there is an implementation where 4G and 5G networks both coexist with each other. In the future, with the increasing usage of mobile devices with 5G support, there will be a gradual migration of 4G networks to 5G, releasing frequency spectrums currently reserved for 4G so that those can be occupied by 5G. The data transmissions in 4G require quite a lot of the processing capacity of all systems within the mobile network. For 5G, the data transmissions, in terms of traffic volume and speed, are larger than 4G transmissions, requiring new systems to be implemented, to allow the processing of larger quantities of data. Implementation in hardware of a 4G Uplink transmission chain, at the physical layer level PHY-Low, will allow the optimization of certain processes that a CPU could handle, reducing CPU usage and time spent on processing. The use of FPGAs makes this possible, as FPGAs can perform parallel tasks simultaneously and perform digital signal processing. The purpose of this dissertation is the modelling of a 4G LTE Uplink transmitter, at the physical layer level. Then, synthesizable VHDL code is generated from the modeled system, which can be eventually implemented in FPGAs. The modelling of the system is made in Simulink, a tool inside the MATLAB software, which allows for modelling, simulating and analyzing systems in a graphic environment and has applications in control systems and digital signal processing. The VHDL code is generated from HDL Coder, another tool in MATLAB software, generating synthesizable Verilog and VHDL code, from the MATLAB functions and Simulink models. The results obtained of processed data from the system are analyzed and validated, comparing the reference data generated from Wireless Waveform Generator toolbox in MATLAB.A tecnologia LTE e LTE-Advanced são standards da quarta geração de comunicações moveis atuais, ou 4G. Futuramente, o 5G marca a próxima geração de comunicações moveis, segundo o standard 5G-New Radio (5GNR). A tecnologia 5G encontra-se numa fase inicial de implementação, sendo que nessa fase uma das suas características fundamentais é o suporte para comunicações 4G, pois muitos dos dispositivos moveis usados atualmente não possuem suporte para comunicações 5G. Este suporte para 4G é tornado possível, se for feita uma implementação onde as redes 4G e 5G se encontrem em coexistência. No futuro, com o aumento do uso de dispositivos moveis com suporte para 5G, haverá uma migração gradual de redes 4G para 5G, libertando os espectros de frequências reservados atualmente para o 4G para serem ocupados pelo 5G. As transmissões de dados no 4G exigem bastante da capacidade de processamento de todos os sistemas da rede movel. Para o 5G, as transmissões de dados tem volumes de tráfego e velocidades maiores do que as transmissões de dados 4G, fazendo com que novos sistemas tenham de ser implementados para poder processar maiores quantidades de dados. A implementação em hardware da cadeia de transmissão 4G Uplink, ao nível da camada física PHY-Low, permitirá a otimização de certos processos que um CPU poderia lidar, diminuindo o uso do CPU e o tempo gasto em processamento. O uso de FPGAs torna isto possível, tendo em conta que podem realizar tarefas em paralelo, em modo simultâneo, e fazer processamento digital de sinal. O objetivo desta dissertação assenta na modelação de um transmissor 4G LTE Uplink, ao nível da camada física. Depois, é gerado código VHDL sintetizável a partir do sistema modelado, que eventualmente será implementada em FPGAs. A modelação do sistema é feito em Simulink, uma ferramenta no software do MATLAB, que permite modelar, simular e analisar sistemas num ambiente gráfico e tem aplicações para sistemas de controlo e processamento digital de sinal. O código VHDL é gerado a partir do HDL Coder, uma outra ferramenta no software do MATLAB, que gera Verilog e VHDL sintetizáveis, a partir de funções MATLAB e de modelos Simulink. Os resultados obtidos dos dados processados pelo sistema são analisados e validados, comparando com os dados de referência obtidos a partir da toolbox Wireless Waveform Generator do MATLAB.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Entrepreneurship during times of crisis: Examining Entrepreneurial Framework Conditions and cultural characteristics during the COVID-19 pandemic

The Global Entrepreneurship Monitor (GEM) model suggests that entrepreneurial activity at the national level varies with Entrepreneurial Framework Conditions (EFCs). Hofstede's perspective, on the other hand, illustrates the effects of a society's culture on the values and behavior of its members. Combining these two perspectives, I empirically test the influence of GEMs entrepreneurial framework conditions and two Hofstede Dimensions on the creation of new companies within the context of the COVID-19 pandemic. Building on data drawn from Global Entrepreneurship Monitor and Hofstede Insights for 28 countries, results suggest that some factors, such as access to entrepreneurial finance, post-schooling entrepreneurial education and social and cultural norms are more relevant than others promoting the creation of new businesses during these difficult times. These findings have implications for theorists and policymakers, which are now more interested than ever in promoting entrepreneurial activity around the world

Public radio in Brazil: reflections on their original conditions, contemporary setting and challenges

Clarify the concept of public radio and certain aspects that relate to the original conditions of such stations in Brazil is the main objective of this work. Therefore, structured in four sessions that dialogue and intertwine: the broadcasting and its mission in the public communication; What is a public radio?; Reflections on the genesis of Brazilian public radio; and considerations on the setting and contemporary challenges of public radio. Methodologically, is based on the structural-historical dialectic approach. In theory, is based on the legal provisions of the Brazilian Constitution, guiding documents of Unesco, studies of Brazilian and European researchers on the subject, as well as the notion of European public broadcasting service. In summary, this paper points out that the understanding of the genesis of public radio in the country valuably contributes to the understanding of the challenges that present themselves to such stations; and the contemporary technological scenario appears to be conducive to the reconfiguration of this service in the convergence environment

Aprendizagem profunda por reforço para tarefas de manipulação robótica

The recent advances in Artificial Intelligence (AI) present new opportunities for robotics on many fronts. Deep Reinforcement Learning (DRL) is a sub-field of AI which results from the combination of Deep Learning (DL) and Reinforcement Learning (RL). It categorizes machine learning algorithms which learn directly from experience and offers a comprehensive framework for studying the interplay among learning, representation and decision-making. It has already been successfully used to solve tasks in many domains. Most notably, DRL agents learned to play Atari 2600 video games directly from pixels and achieved human comparable performance in 49 of those games. Additionally, recent efforts using DRL in conjunction with other techniques produced agents capable of playing the board game of Go at a professional level, which has long been viewed as an intractable problem due to its enormous search space. In the context of robotics, DRL is often applied to planning, navigation, optimal control and others. Here, the powerful function approximation and representation learning properties of Deep Neural Networks enable RL to scale up to problems with highdimensional state and action spaces. Additionally, inherent properties of DRL make transfer learning useful when moving from simulation to the real world. This dissertation aims to investigate the applicability and effectiveness of DRL to learn successful policies on the domain of robot manipulator tasks. Initially, a set of three classic RL problems were solved using RL and DRL algorithms in order to explore their practical implementation and arrive at class of algorithms appropriate for these robotic tasks. Afterwards, a task in simulation is defined such that an agent is set to control a 6 DoF manipulator to reach a target with its end effector. This is used to evaluate the effects on performance of different state representations, hyperparameters and state-of-the-art DRL algorithms, resulting in agents with high success rates. The emphasis is then placed on the speed and time restrictions of the end effector's positioning. To this end, different reward systems were tested for an agent learning a modified version of the previous reaching task with faster joint speeds. In this setting, a number of improvements were verified in relation to the original reward system. Finally, an application of the best reaching agent obtained from the previous experiments is demonstrated on a simplified ball catching scenario.Os avanços recentes na Inteligência Artificial (IA) demonstram um conjunto de novas oportunidades para a robótica. A Aprendizagem Profunda por Reforço (DRL) é uma subárea da IA que resulta da combinação de Aprendizagem Profunda (DL) com Aprendizagem por Reforço (RL). Esta subárea define algoritmos de aprendizagem automática que aprendem diretamente por experiência e oferece uma abordagem compreensiva para o estudo da interação entre aprendizagem, representação e a decisão. Estes algoritmos já têm sido utilizados com sucesso em diferentes domínios. Nomeadamente, destaca-se a aplicação de agentes de DRL que aprenderam a jogar vídeo jogos da consola Atari 2600 diretamente a partir de pixels e atingiram um desempenho comparável a humanos em 49 desses jogos. Mais recentemente, a DRL em conjunto com outras técnicas originou agentes capazes de jogar o jogo de tabuleiro Go a um nível profissional, algo que até ao momento era visto como um problema demasiado complexo para ser resolvido devido ao seu enorme espaço de procura. No âmbito da robótica, a DRL tem vindo a ser utilizada em problemas de planeamento, navegação, controlo ótimo e outros. Nestas aplicações, as excelentes capacidades de aproximação de funções e aprendizagem de representação das Redes Neuronais Profundas permitem à RL escalar a problemas com espaços de estado e ação multidimensionais. Adicionalmente, propriedades inerentes à DRL fazem a transferência de aprendizagem útil ao passar da simulação para o mundo real. Esta dissertação visa investigar a aplicabilidade e eficácia de técnicas de DRL para aprender políticas de sucesso no domínio das tarefas de manipulação robótica. Inicialmente, um conjunto de três problemas clássicos de RL foram resolvidos utilizando algoritmos de RL e DRL de forma a explorar a sua implementação prática e chegar a uma classe de algoritmos apropriados para estas tarefas de robótica. Posteriormente, foi definida uma tarefa em simulação onde um agente tem como objetivo controlar um manipulador com 6 graus de liberdade de forma a atingir um alvo com o seu terminal. Esta é utilizada para avaliar o efeito no desempenho de diferentes representações do estado, hiperparâmetros e algoritmos do estado da arte de DRL, o que resultou em agentes com taxas de sucesso elevadas. O foco é depois colocado na velocidade e restrições de tempo do posicionamento do terminal. Para este fim, diferentes sistemas de recompensa foram testados para que um agente possa aprender uma versão modificada da tarefa anterior para velocidades de juntas superiores. Neste cenário, foram verificadas várias melhorias em relação ao sistema de recompensa original. Finalmente, uma aplicação do melhor agente obtido nas experiências anteriores é demonstrada num cenário implicado de captura de bola.Mestrado em Engenharia de Computadores e Telemátic

Use of flight interception traps of Malaise type and attractive traps for social wasps record (Vespidae: Polistinae)

The literature provides different methodologies for sampling social wasps, including, flight intercept trap type Malaise and Attractive trap, however, there is no consensus on its use. In this respect, the aim of this study was to evaluate the best use of Malaise traps and Attractive trap in biodiversity work of social wasps, and generate a collection protocol for the use of these traps. The study was conducted in the Parque Estadual do Rio Doce, located in the east of the state of Minas Gerais, in the years 2000, 2001, 2002 and 2004 and in the Botanical Garden of the Federal University of Juiz de Fora, located in the southeastern state of Minas Gerais, in years 2011, 2012 and 2013. 15 species were collected using Malaise traps, and, 26 species of social wasps were collected using Attractive traps. Although the negative aspects of both traps, complementary methodologies surveys varying social wasps are useful and it is recommended to choose for using in accordance with the logistical field

Water diffusion in rough carbon nanotubes

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of deformation at 300 K. We found that the number of hydrogen bonds that water forms depends on nanotube topology, leading to enhancement or suppression of water diffusion. The simulation results reveal that more realistic nanotubes should be considered to understand the confined water diffusion behavior, at least for the narrowest nanotubes, when the interaction between water molecules and carbon atoms is relevant.Comment: 17 pages, 8 figure

Activity schedule and foraging in Protopolybia sedula (Hymenoptera, Vespidae)

Protopolybia sedula is a social swarming wasp, widely spread throughout many countries in the Americas, including most of Brazil. Despite its distribution, studies of its behavioral ecology are scarce. This study aimed to describe its foraging activity and relation to climatic variables in the city of Juiz de Fora in southeastern Brazil. Three colonies were under observation between 07:00 and 18:00 during April 2012, January 2013, and March 2013. Every 30 minutes, the number of foragers leaving and returning to the colony was registered along with air temperature and relative humidity. Activity began around 07:30¸ increased between 10:30 and 14:30, and ended around 18:30. A mean of 52.7 exits and 54 returns were measured every 30 minutes. The daily mean values were 1,107 ± 510.6 exits and 1,135 ± 854.8 returns. Only one colony showed a significant correlation between forager exits and temperature (rs = 0.8055; P \u3c 0.0001) and between exits and relative humidity (rs = -0.7441; P = 0.0001). This paper shows that climatic variables are likely to have little control on the foraging rhythm of P. sedula when compared to other species, suggesting the interaction of other external and internal factors as stimuli of species foraging behavio

Formação docente e as relações dialéticas da brincadeira e do jogo nas teorias de Elkonin, Vigotski, Luria, Leontiev e Wallon

The article aims to analyze the dialectical relationships of play and game in the field of education, as activities that promote human development in a historical-social-cultural and dialectical perspective, referenced in Elkonin theories (2009, 2017) , Vigotski (2017, 2008, 1996), Leontiev (2010, 1983), Luria (1992, 2010) and Wallon (1975, 2007). One has as a problem: what theoretical determinations do the authors Elkonin, Vigotski, Leontiev, Luria and Wallon present regarding the perception and development of play and play as: activity, human development and teaching resource? In this perspective, fundamental elements are highlighted in the theories of the mentioned authors determining their main contributions, based on the historical-dialectical method for analysis evidenced in the work of Marx (1968, 1982) and Vicente (2007). Next, some considerations are developed, signaling a theoretical approximation, through dialectical historical materialism, about the knowledge of play and game, developing categories of totality, contradiction, movement and transformation.El artículo se presenta con el objetivo de analizar las relaciones dialécticas del juego y el juego en el campo de la educación, como actividades que promueven el desarrollo humano en una perspectiva histórico-social-cultural y dialéctica, haciendo referencia a las teorías de Elkonin (2009, 2017), Vigotski. (2017, 2008, 1996), Leontiev (2010, 1983), Luria (1992, 2010) y Wallon (1975, 2007). El problema es: ¿qué determinaciones teóricas presentan los autores Elkonin, Vigotski, Leontiev, Luria y Wallon sobre la percepción y el desarrollo del juego y el juego como actividad, desarrollo humano y recurso didáctico? Desde esta perspectiva, se destacan elementos fundamentales en las teorías de los autores mencionados, determinando sus principales aportes, basados ​​en el método histórico-dialéctico de análisis, como se evidencia en el trabajo de Marx (1968, 1982) y Vicente (2007). Luego, se desarrollan algunas consideraciones, señalando un acercamiento teórico, a través del materialismo histórico-dialéctico, sobre el conocimiento de los juegos y los juegos, desarrollando categorías de totalidad, contradicción, movimiento y transformación.The article aims to analyze the dialectical relationships of play and game in the field of education, as activities that promote human development in a historical-social-cultural and dialectical perspective, referenced in Elkonin theories (2009, 2017) , Vigotski (2017, 2008, 1996), Leontiev (2010, 1983), Luria (1992, 2010) and Wallon (1975, 2007). One has as a problem: what theoretical determinations do the authors Elkonin, Vigotski, Leontiev, Luria and Wallon present regarding the perception and development of play and play as: activity, human development and teaching resource? In this perspective, fundamental elements are highlighted in the theories of the mentioned authors determining their main contributions, based on the historical-dialectical method for analysis evidenced in the work of Marx (1968, 1982) and Vicente (2007). Next, some considerations are developed, signaling a theoretical approximation, through dialectical historical materialism, about the knowledge of play and game, developing categories of totality, contradiction, movement and transformation.O artigo apresenta-se com o objetivo de analisar as relações dialéticas da brincadeira e do jogo no campo da educação, como atividades que promovem o desenvolvimento humano em uma perspectiva histórico-social-cultural e dialética, referenciando-se nas teorias de Elkonin (2009, 2017), Vigotski (1996, 2008, 2017), Leontiev (1983, 2010), Luria (1992, 2010) e Wallon (1975, 2007). Tem-se como problema: quais determinações teóricas os autores Elkonin, Vigotski, Leontiev, Luria e Wallon apresentam quanto à percepção e ao desenvolvimento da brincadeira e do jogo como atividade, desenvolvimento humano e recurso de ensino? Nessa perspectiva, destacam-se elementos fundamentais nas teorias dos autores mencionados determinando suas principais contribuições para sustentar as ações do trabalho docente. Apoia-se no método histórico-dialético para análise, evidenciado na obra de Marx (1968, 1982) e de Vicente (2007). Em seguida, desenvolvem-se algumas considerações, sinalizando uma aproximação teórica, por meio do materialismo histórico-dialético sobre os conhecimentos da brincadeira e do jogo, desenvolvendo categorias de totalidade, contradição, movimento e transformação