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Fuel optimal low thrust trajectories for an asteroid sample return mission /Rust, Jack W. January 2005 (has links) (PDF)
Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): I. Michael Ross. Includes bibliographical references (p. 57-58). Also available online.
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Trajectory reconstruction by analysis of trace evidence on spent bullets fired through building materials: analysis by microscopy and direct analysis in real timeEdison, William James 12 March 2016 (has links)
Trajectory reconstruction of shooting incidents can help investigators determine critical case information regarding the number of shooters involved, their location(s), and intent. The examination of trace amounts of intermediate target materials collected on the surface of spent bullets provides crucial information needed for trajectory reconstruction. Determining the origin of an unknown material adhered to a spent bullet allows for the identification of intermediate targets the bullet either contacted or penetrated during flight. Although significant information can be obtained from examination of these trace materials adhered to spent bullets, this aspect of trajectory reconstruction is often ignored.
The ability of different bullet types to collect trace materials from intermediate targets and the ability to associate these trace materials to their origin was examined using microscopy and Direct Analysis in Real Time (DART). Full metal jacket (FMJ), jacketed hollow point (JHP), and lead round nose (LRN) bullets were fired into sheets of five different commonly used building materials (oriented strand board, sanded plywood, white melamine board, synthetic PVC board, and medium density fiberboard) to produce a total of 45 spent bullets to be examined.
All spent bullets were examined and photographed using a DSLR camera paired with a stereomicroscope. The spent bullets were then examined using DART/MS to determine if any ion profiles generated from the trace materials could be associated with those of the intermediate target building materials which the bullets were fired through.
The collection of trace material from all five types used was highly dependent on the type of bullet. Very minimal amounts of trace materials were observed on the majority of LRN bullets, which failed to produce an identifiable ion signature. The FMJ bullets that were fired through PVC material collected trace material that produced an ion profile, while all other building materials failed to transfer to the FMJ bullets. All JHP bullets collected significant amounts of the five building materials tested inside the hollow point cavity and along the nose of the bullet. In every spent JHP bullet sample, the trace material collected produced a unique ion profile. Additionally, MS data from four of the five building materials tested matched the MS data generated from trace material collected on JHP bullets from the respective target materials.
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Ambient air pollution in Massachusetts: inequality trends, residential infiltration, and childhood weight growth trajectoriesRosofsky, Anna Stillman 18 March 2018 (has links)
Exposure to pollutants of ambient origin contributes significantly to the global disease burden (Cohen et al., 2017). Mounting evidence has demonstrated disproportionately high ambient PM2.5 and NO2 concentrations in the U.S. among nonwhite and low-income populations, potentially contributing to environmental health disparities (Bell and Ebisu, 2012; Clark et al., 2014; Morello-Frosch and Lopez, 2006). There is limited understanding of temporal trends and underlying causes of exposure inequalities (EIs), and whether residential building characteristics modify observed EIs. Further, while ambient pollutants have been linked to cardiometabolic disease in adulthood, few studies have documented the link between early-life ambient air pollution exposure and weight growth trajectories in early childhood- an informative step on the causal pathway between early life exposures and chronic outcomes.
Using 1 km2 PM2.5 and NO2 predictions in Massachusetts and Census data, we quantify longitudinal EI between sociodemographic groups over a decade. We estimate AER for all Massachusetts residential parcels using publicly available data and assess whether accounting for AER exacerbates or ameliorates PM2.5 inequalities. We examine associations of weight growth trajectories in early childhood with residential prenatal and postnatal PM2.5 and distance to road (traffic) exposure in the Boston-based Children’s HealthWatch cohort.
PM2.5 and NO2 inequalities increased across the study period in urban areas, and EIs were more pronounced for NO2 than PM2.5 and among racial/ethnic groups compared to other population subgroups. Analyzing EI longitudinally revealed that spatio-temporal shifts in air pollution, and not demographic distributions, contributed to exposure disparities. We found substantial variability in estimated AER across the state, and that PM2.5 EIs were magnified when AER was considered. Prenatal PM2.5 >9.5 µg/m3 predicted higher weight growth rates among females, but with an opposite direction of effect in males. This association was modified by birth weight and AER, with a stronger magnitude of effect in low-birthweight and higher-AER females.
These findings underscore the importance of considering vulnerable communities and residential characteristics in ambient air pollution reduction strategies. This dissertation provides an opportunity to understand susceptible phenotypes and periods of potential intervention to reduce ambient air pollution impacts on cardiometabolic outcomes. / 2020-03-17T00:00:00Z
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A construção da trajetória profissional de contadores a partir da experiência em uma Big FourFeijó, Carla dos Santos January 2016 (has links)
Este estudo objetivou analisar de que modo a vivência em uma das maiores empresas mundiais de auditoria (Big Four) influenciou na construção das trajetórias de carreira dos contadores que lá tiveram experiência como auditor ou consultor. Para a realização desta pesquisa qualitativa contou-se com a participação de catorze contadores que trabalham ou trabalharam nestas organizações. A coleta de dados ocorreu por meio de entrevista semiestruturada. A apresentação dos resultados foi organizada em 20 categorias iniciais, que deram origem a 7 intermediárias e 3 categorias finais de análise. Elas dizem respeito às expectativas e idealizações no início da carreira, à experiência vivenciada na Big e às mudanças de perspectivas pessoais e profissionais impactando nas decisões de carreira dos entrevistados. Esta dissertação possibilitou perceber, pela visão dos contadores entrevistados, que a experiência nestas empresas gera influências significativas, que poderiam ser considerados legados, tanto profissionais como pessoais para os indivíduos, devido ao dinamismo, definido por eles como diferenciado, a que essas pessoas ficaram sujeitas. Além disso, verificou-se que para quem decide sair dessas instituições, há uma alta empregabilidade no mercado de trabalho e, para os que decidem permanecer, há a possibilidade de se tornar sócio, dependendo das suas escolhas e direcionamentos das trajetórias de carreira, que são baseadas nos gostos e preferências pessoais, mas também influenciada pelo meio social no qual essas pessoas estão inseridas. Mostrou-se forte, nesta pesquisa, a influência da família para o direcionamento das escolhas e da constituição das trajetórias profissionais. Revelaram-se experiências nas Bigs enquanto carreiras organizacionais, hierarquizadas, em um ambiente com altas demandas de trabalho e priorização da carreira em detrimento à vida pessoal; entretanto, ao longo do tempo as mudanças de vida que ocorreram, demandaram, em determinado momento, um maior equilíbrio entre vida pessoal e profissional, que foi o maior direcionador das escolhas das novas trajetórias. O dilema das auditoras e o interesse pela docência, que a maioria dos entrevistados demonstrou, também são resultados desta pesquisa. / This study analyzed how the experience in one of the largest audit firms (Big Four) influenced the construction of the Accountant career trajectories while auditor or consultant. For the realization of this qualitative research was counted with the participation of fourteen accountants who work or have worked in these organizations. The data were collected through semi-structured interview. The presentation of the results was organized in 20 initial categories, which gave rise to 7 intermediate and final 3 categories of analysis. They relate to expectations and idealizations early in his career, to the experience of the Big and changes of personal and professional perspectives impacting on the respondents career decisions. This work made it possible to realize, by the interviewees counters that the experience these companies generate significant influences, which could be considered legacy, both professional and personal to individuals, due to the dynamics defined by them as differentiated, that these people were subject. Moreover, it was found that for those who decide to leave these institutions, there is a high employability in the labor market and for those who decide to stay, there is the possibility of becoming a partner, depending on your choices and directions of career paths that they are based on personal tastes and preferences, but also influenced by the social environment in which these people are located. Proved to be strong in this research, the family influence on the direction of the choices and the establishment of professional trajectories. They have proven experience in the Bigs as organizational, hierarchical careers in an environment with high job demands and prioritizing career over personal life; however, over time the life changes that occurred, demanded at any given time, a better balance between personal and professional life, which was the biggest driver of the choices of new paths. The dilemma of auditing and interest in teaching, most of them show, are also results of this research.
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A Heuristic Search Algorithm for Asteroid Tour MissionsBilal, Mohd January 2018 (has links)
Since the discovery of Ceres, asteroids have been of immense scientific interest and intrigue. They hold answers to many of the fundamental questionsabout the formation and evolution of the Solar System. Therefore, a missionsurveying the asteroid belt with close encounter of carefully chosen asteroidswould be of immense scientific benefit. The trajectory of such an asteroidtour mission needs to be designed such that asteroids of a wide range ofcompositions and sizes are encountered; all with an extremely limited ∆Vbudget.This thesis presents a novel heuristic algorithm to optimize trajectoriesfor an asteroid tour mission with close range flybys (≤ 1000 km). The coresearch algorithm efficiently decouples combinatorial (i.e. choosing the asteroids to flyby)and continuous optimization (i.e. optimizing critical maneuversand events) of what is essentially a mixed integer programming problem.Additionally, different methods to generate a healthy initial population forthe combinatorial optimization are presented.The algorithm is used to generate a set of 1800 feasible trajectories withina 2029+ launch frame. A statistical analysis of these set of trajectories isperformed and important metrics for the search are set based on the statistics.Trajectories allowing flybys to prominent families of asteroids like Flora andNysa with ∆V as low as 4.99 km/s are obtained.Two modified implementations of the algorithm are presented. In a firstiteration, a large sample of trajectories is generated with a limited numberof encounters to the most scientifically interesting targets. While, a posteriori, trajectories are filled in with as many small targets as possible. Thisis achieved in two different ways, namely single step extension and multiplestep extension. The former fills in the trajectories with small targets in onestep, while the latter optimizes the trajectory by filling in with one asteroid per step. The thesis also presents detection of asteroids for successfullyperforming flybys. A photometric filter is developed which prunes out badlyilluminated asteroids. The best trajectory is found to perform well againstthis filter such that nine out of the ten planned flybys are feasible.
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A experiência de pesquisa na formação básica e seu impacto na atuação docente na visão de profissionais do ensino fundamental IOnofre, Márcia Regina [UNESP] January 2006 (has links) (PDF)
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onofre_mr_dr_arafcl.pdf: 2010952 bytes, checksum: 9b6f2cb3bf1b3d5dc7abc4e61dbfe557 (MD5) / A pesquisa, aqui apresentada, defende a idéia de que professores formados em Cursos de Pedagogia, com licenciatura plena de 4 anos, em instituições públicas ou particulares conceituadas e que participaram, ao longo da graduação, de Programas Especiais de Estudo, Grupos de Estudos, Monitorias, Projetos de Pesquisa e Extensão e, especialmente de atividades de Iniciação à Pesquisa tendem a ter uma trajetória e desempenho profissionais diferenciados em relação aos demais professores. O objetivo do estudo foi o de investigar o impacto específico das experiências de iniciação à pesquisa no processo de formação inicial e no desempenho profissional de professores/as do Ensino Fundamental I da Secretaria Municipal de Educação de Araraquara. Para a obtenção dos dados foi realizada, em 2004, uma pesquisa preliminar, por meio de questionários distribuídos a 259 profissionais atuantes como docentes e como especialistas nas equipes técnicas das escolas de Ensino Fundamental I da Secretaria Municipal de Araraquara, com o objetivo de traçar o perfil pessoal, bem como caracterizar a trajetória de formação e a carreira desses profissionais. Desse total (259), foram devolvidos 142 questionários. A pesquisa revelou que desses 142 profissionais respondentes, 32 ou 25,60% revelavam trajetória profissional diferenciada, ocupando posições de destaque na Secretaria: 16 atuando nas funções de coordenadores, diretores e assistentes educacionais pedagógicos e 16 atuando em salas de aula como professoras da rede de ensino municipal. Com o apoio teórico de autores como Pérez Gómez, Antonio Contreras e Henry Giroux e focalizando, especificamente, as16 professoras que permaneciam nas salas de aula exercendo funções docentes foram realizadas entrevistas intensivas, buscando analisar, nos depoimentos das professoras... / The present study defends the idea that teachers who have graduated from Pedagogy courses in respected public or private institutions and who participated, during their graduation, in Special Study Programs, Study Groups, Tutoring, Research and Extension Projects and especially in activities of initial research tend to have differentiated trajectory and professional performance in relation to other teachers. The objective of this work was to investigate the specific impact of the experiences in research in the process of initial formation and in the professional performance of Middle School teachers of municipal schools in Araraquara. Preliminary research was accomplished in 2004 to obtain the data by means of questionnaires distributed to 259 professionals among teachers and specialists from Middle School teams in Araraquara, aiming to trace their personal profile as well as to characterize their formation trajectory and career. Of this total (259), 142 questionnaires were returned. The research showed that 142 of the respondents, 32 or 25.60% revealed differentiated professional trajectory: 16 were coordinators, directors and pedagogic assistants and 16 were teachers in municipal schools. Accomplished in 2005 and theoretically supported by authors such as Pérez Gómez, Gimeno Sacristán and Henry Giroux, intensive interviews aimed at the analysis of the relation established by these 16 teachers between their research experiences in their initial formation and the exercise of their profession. The results obtained in the second stage of the research indicate that in these teachers' view: initial formation constitutes fundamental learning for the building of knowledge necessary to teachersþ work; initiation activities to research, participation in study groups, extension projects and services to the community and, especially... (Complete abstract, click electronic address below)
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A construção da trajetória profissional de contadores a partir da experiência em uma Big FourFeijó, Carla dos Santos January 2016 (has links)
Este estudo objetivou analisar de que modo a vivência em uma das maiores empresas mundiais de auditoria (Big Four) influenciou na construção das trajetórias de carreira dos contadores que lá tiveram experiência como auditor ou consultor. Para a realização desta pesquisa qualitativa contou-se com a participação de catorze contadores que trabalham ou trabalharam nestas organizações. A coleta de dados ocorreu por meio de entrevista semiestruturada. A apresentação dos resultados foi organizada em 20 categorias iniciais, que deram origem a 7 intermediárias e 3 categorias finais de análise. Elas dizem respeito às expectativas e idealizações no início da carreira, à experiência vivenciada na Big e às mudanças de perspectivas pessoais e profissionais impactando nas decisões de carreira dos entrevistados. Esta dissertação possibilitou perceber, pela visão dos contadores entrevistados, que a experiência nestas empresas gera influências significativas, que poderiam ser considerados legados, tanto profissionais como pessoais para os indivíduos, devido ao dinamismo, definido por eles como diferenciado, a que essas pessoas ficaram sujeitas. Além disso, verificou-se que para quem decide sair dessas instituições, há uma alta empregabilidade no mercado de trabalho e, para os que decidem permanecer, há a possibilidade de se tornar sócio, dependendo das suas escolhas e direcionamentos das trajetórias de carreira, que são baseadas nos gostos e preferências pessoais, mas também influenciada pelo meio social no qual essas pessoas estão inseridas. Mostrou-se forte, nesta pesquisa, a influência da família para o direcionamento das escolhas e da constituição das trajetórias profissionais. Revelaram-se experiências nas Bigs enquanto carreiras organizacionais, hierarquizadas, em um ambiente com altas demandas de trabalho e priorização da carreira em detrimento à vida pessoal; entretanto, ao longo do tempo as mudanças de vida que ocorreram, demandaram, em determinado momento, um maior equilíbrio entre vida pessoal e profissional, que foi o maior direcionador das escolhas das novas trajetórias. O dilema das auditoras e o interesse pela docência, que a maioria dos entrevistados demonstrou, também são resultados desta pesquisa. / This study analyzed how the experience in one of the largest audit firms (Big Four) influenced the construction of the Accountant career trajectories while auditor or consultant. For the realization of this qualitative research was counted with the participation of fourteen accountants who work or have worked in these organizations. The data were collected through semi-structured interview. The presentation of the results was organized in 20 initial categories, which gave rise to 7 intermediate and final 3 categories of analysis. They relate to expectations and idealizations early in his career, to the experience of the Big and changes of personal and professional perspectives impacting on the respondents career decisions. This work made it possible to realize, by the interviewees counters that the experience these companies generate significant influences, which could be considered legacy, both professional and personal to individuals, due to the dynamics defined by them as differentiated, that these people were subject. Moreover, it was found that for those who decide to leave these institutions, there is a high employability in the labor market and for those who decide to stay, there is the possibility of becoming a partner, depending on your choices and directions of career paths that they are based on personal tastes and preferences, but also influenced by the social environment in which these people are located. Proved to be strong in this research, the family influence on the direction of the choices and the establishment of professional trajectories. They have proven experience in the Bigs as organizational, hierarchical careers in an environment with high job demands and prioritizing career over personal life; however, over time the life changes that occurred, demanded at any given time, a better balance between personal and professional life, which was the biggest driver of the choices of new paths. The dilemma of auditing and interest in teaching, most of them show, are also results of this research.
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Por que ser licenciado em CiÃncias Sociais? Um estudo sobre os significados da escolha profissional / Why obtain a graduate degree in Social Science? A study about the significance of professional choice.PatrÃcia Silva Xavier 21 July 2016 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / O estudo busca compreender os significados da escolha, por parte dos egressos, pela modalidade Licenciatura no curso de CiÃncias Sociais na Universidade Federal do Cearà entre os anos de 2002 a 2008. Esse momento corresponde ao perÃodo em que a disciplina de Sociologia ainda nÃo fazia parte da grade curricular obrigatÃria do Ensino MÃdio, tendo sido incorporado somente em 2008, com a aprovaÃÃo da Lei Nacional n 11684/08 que assegurou o seu retorno. Pretende-se entender como os estudantes conduziram suas trajetÃrias em um perÃodo que nÃo se tinha um campo profissional institucionalizado, da mesma forma procura saber como o curso de CiÃncias Sociais na modalidade Licenciatura era organizado, se havia incentivos para a sua escolha ou discussÃes a respeito da profissÃo de professor, seus campos de atuaÃÃo e quais as perspectivas de formaÃÃo apresentadas nos Projetos PolÃticos PedagÃgicos da Licenciatura. O trabalho configura-se numa anÃlise dos discursos dos egressos, se utilizando de tÃcnicas de pesquisa qualitativa. As respostas foram obtidas por meio de entrevistas semiestruturadas com egressos e na pesquisa documental com anÃlise de documentos (Projeto PolÃtico PedagÃgico, Ementas e conteÃdos das disciplinas, dentre outros). Foi utilizado autores que discutem a Licenciatura e a Sociologia no Ensino MÃdio. Os resultados da pesquisa identificam os percalÃos na construÃÃo desta formaÃÃo, pois naquele tempo nÃo havia polÃticas de incentivo. Conclui-se que os estudantes formados durante esse perÃodo na Licenciatura nÃo chegam à metade dos formandos no curso de CiÃncias Sociais. / The study seeks to understand the meanings of choice by the students, by
the Course mode in the course of Social Sciences at the Federal University of CearÃ
between the years 2002 to 2008. This time corresponds to the period in which
sociology discipline was not part the compulsory curriculum of high school, having
been built only in 2008, with the approval of the National Law No. 11684/08 which
ensured his return. I intend to understand how the students conducted their
trajectories in a period that was not an institutionalized professional field, I also seek
to understand how the course of Social Sciences in the mode degree was organized,
if there were incentives to choice or discussions concerning the teaching profession,
their areas of operation and what the prospects for training presented in politicalpedagogical
projects of degree course. The work sets up an analysis of the speeches
of the graduates, using qualitative research techniques.The answers will be sought
through semi-structured interviews with egresses and documentary research with
analysis of documents (political pedagogical project, syllabus and disciplines
content). It was used authors discussing Degree and sociology in high school. The
survey results identify the mishaps in building this career because at that time there
was no incentive policies. It was concluded that the students graduated during this
period the degree does not reach half of the trainees in the Social Sciences course.
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Sacerdotisa em Laranjeiras/SE : trajetória e recursos na ocupação de um espaço de poder e dominação / PRIESTESS IN LARANJEIRAS / SE: trajectory and resources in occupying a space of power and domination.Cruz, Eval 09 July 2012 (has links)
This work analyzes the trajectory and the resources provided by the current "Alôxa" of the "Irmandade Santa Bárbara Virgem" in the city of Laranjeiras, in Sergipe, for the occupation of an space of power. The study discusses the conditions for the formation of this agent as a priestess, from the perspective of Bourdieu's analysis. Thus, in addition to review of the historical context that led to the setting of Laranjeiras as a privileged space for the development of a religious field of African s descent, we evaluate the symbolic capital, the social capital and the school capital used by the agent. For this purpose, a literature review is used as soon as main expedients: ethnographic research, the construction of a diary, the application of a structured interview and some "informal conversations" with participants in the "Irmandade". If, on the one hand, it is clear that, according to the logic of the house of worship, a priestess is chosen by "the desire of the orixás", on the other hand, it appears that the scope of the control group occurs after a period of dispute with other agents. Moreover, it is observed that the preparation of "Alôxa" is articulated to a long process of learning the functions of leadership, a legacy established by living with her mother, also a "priestess", and the incorporation of a religious capital from the participation in cults and festivals. / Este trabalho analisa a trajetória e os recursos mobilizados pela atual Alôxa do terreiro Irmandade Santa Bárbara Virgem na cidade de Laranjeiras, no Estado de Sergipe, para a ocupação deste espaço de poder. O estudo versa sobre as condições de constituição desta agente como sacerdotisa, a partir de uma perspectiva bourdieusiana de análise. Deste modo, além da averiguação do contexto histórico que possibilitou a configuração de Laranjeiras como um espaço privilegiado para o desenvolvimento de um campo religioso afrodescendente, avalia-se os capitais simbólicos, social e escolar utilizados pela agente. Para este fim, além de uma revisão bibliográfica, utiliza-se como principais expedientes a pesquisa etnográfica, a construção de um diário de campo, a aplicação de um roteiro de entrevista e algumas conversas informais com participantes da Irmandade . Se, por um lado, é possível constatar que, segundo a lógica da casa de culto, uma sacerdotisa é escolhida por vontade dos orixás , por outro lado, verifica-se que o alcance do comando do grupo se dá após um período de disputa, juntamente com outros agentes. Ademais, observa-se que a preparação da Alôxa se articulou a um longo processo de aprendizagem das funções de liderança, uma herança estabelecida através da vivência com sua mãe, também sacerdotisa , e da incorporação de um capital religioso a partir da participação nos cultos e festejos.
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Restauração florestal de áreas mineradas de bauxita: é necessário o uso de gramíneas exóticas para o recobrimento inicial do solo? / Forest restoration of mined bauxite areas: it is necessary the use of exotic grasses for initial soil cover?Vanessa de Souza Moreno 22 January 2015 (has links)
A mineração modifica profundamente os ecossistemas naturais e, embora a recuperação dessas áreas seja exigida pela legislação, trata-se ainda de um grande desafio técnico. Geralmente, as estratégias de recuperação envolvem a distribuição de solo florestal superficial, a semeadura de gramíneas exóticas para cobrir o solo, chamada de \"tapete verde\", e o plantio de mudas de árvores exóticas e/ou nativas. No entanto, a semeadura de gramíneas exóticas pode restringir a regeneração de espécies nativas, sendo a avaliação da sua viabilidade ecológica necessária para determinar sua real necessidade. Nesse contexto, o objetivo desse trabalho foi avaliar se é necessário o uso de gramíneas exóticas para o recobrimento inicial do solo na recuperação de florestas tropicais em áreas de mineração de bauxita, bem como se a trajetória ecológica gerada apresenta potencial de retorno às condições pré-distúrbio. Sendo assim, utilizamos um estudo de caso de recuperação de minas de exploração de bauxita na Mata Atlântica do Brasil na região de Poços de Caldas-MG, na qual foram comparadas cronossequências de dois métodos de restauração de minas de bauxita - restauração florestal sem tapete verde (Rs) e restauração florestal com tapete verde (Rc) - tendo-se trechos de floresta nativa como ecossistema de referência. Foram avaliados dados de estrutura (cobertura de gramínea, cobertura de dossel, área basal, densidade de indivíduos com DAP ≥ 1 cm e altura ≥130 cm - classe 1 - e densidade de indivíduos com DAP < 1 cm e altura ≥ 50 cm - classe 2) e composição (riqueza, diversidade, equabilidade, riqueza e porcentagem de espécies por síndrome de dispersão). A definição da trajetória ecológica foi realizada por meio de regressões lineares. O método de restauração florestal sem tapete verde alcançou resultados superiores ao método Rc em parâmetros importantes para o estabelecimento da floresta, como cobertura de gramíneas, cobertura de dossel, riqueza e diversidade da classe 1. O método Rs também teve resultados semelhantes à Rc em vários parâmetros, apesar da idade inferior. Os dois métodos apresentaram tendências de evolução em direção aos parâmetros do ecossistema de referência, porém o método Rs, se mantiver a trajetória atual, pode alcançá-los mais rapidamente, o que reduz gastos com manutenção e manejo. Tais evidências mostram que o uso de gramíneas exóticas para recobrimento inicial de áreas mineradas não é necessário em projetos que visem à restauração florestal de áreas de mineração, pois essas prejudicam o restabelecimento da dinâmica florestal. Adicionalmente, mostrou-se ser possível recuperar áreas mineradas de bauxita com metas ecológicas mais ambiciosas, que visem o retorno de condições similares às existentes pré-distúrbio. / Mining profoundly alters natural ecosystems and, although the recovery of these areas is required by law, it is still a major technical challenge. Generally, recovery strategies involve the distribution of surface forest soil, planting of exotic grasses to cover the ground and the planting of exotic and/or native trees. However, the sowing of exotic grasses may restrict native species regeneration, therefore, context specific diagnosis must be carried out to determine the actual need of using such technique. In this context, the aim of this study was to evaluate whether the use of exotic grasses for initial soil covering in the recovery of tropical forests in areas of bauxite mining is necessary, as well as if the restored community has potential to return to the pre-disturbance conditions. Therefore, we use a case study of recovery of bauxite exploration in the Atlantic Forest region of Brazil in Pocos de Caldas, Minas Gerais, where chronosequences of two methods of restoration of bauxite mines were compared - restoration without exotic grasses (Rs) and forest restoration with exotic grasses (Rc) - taking up stretches of native forest ecosystem as a reference. We collected data on tree community structure (grass cover, canopy cover, basal area, and density of individuals CBH ≥3.1 cm and height ≥ 130 cm (1 class) and density of individuals DAP < 3.1 cm and height ≥ 50 cm (class 2) and composition (richness, diversity, evenness and richness and percentage of species by dispersion syndrome). The successional path was analyzed by linear regression. In class 1, the method of forest restoration without exotic grasses (Rs) achieved better results than Rc in key parameters for forest establishment, such as exotic grass cover, canopy cover, richness and diversity. The Rs method also had similar results to Rc in several parameters, despite being represented by younger communities. Both methods showed trends toward the parameters values found in reference ecosystem, but Rs method, if it remain the current way, can reach these values more quickly, which reduces maintenance costs and management. Such evidence shows that the use of exotic grasses for initial covering of mined areas is not necessary in projects aimed at forest restoration of mining areas, as these hinder the restoration of forest dynamics. Additionally, we proved to be possible to recover the bauxite mined areas with more ambitious ecological goals, aiming at the return of pre-disturbance conditions.
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