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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

Social environment influences impulsivity in red junglefowl (Gallus gallus) chicks

Andersson, Emelie January 2019 (has links)
Cognition (i.e. how individuals perceive, process and react to environmental cues) is fundamental to all animals’ life. Despite this, what explains variation in cognitive abilities is still mainly unclear. Environment is assumed to influences cognitive variation, but the mechanisms for this are still unknown. According to the social intelligence hypothesis, living in a group with a rich social environment, generate challenges that can enhance cognitive abilities. Impulsivity (to not be able to inhibit impulses), one aspect of cognition, may be influenced by the social environment, however this has not yet been experimentally tested. Impulsivity can complicate life, both for humans and animals. In humans, high levels of impulsivity and lack of self-control are associated with addictions and psychiatric disorders, thus is considered to be maladaptive. In animals, impulsivity correlates with stereotypies. To improve our understanding of impulsivity, I experimentally investigated how early social environment affects individual variation in impulsivity. To test this, red junglefowl chicks were used because their group living nature, and our accumulated knowledge on their cognition and behaviour. To manipulate the social environment, chicks either grew up in larger groups (with 17 individuals) or smaller groups (with 7 individuals). During the chicks’ first five weeks of life, three aspects of impulsivity were tested; impulsive action, persistence (in a detour reaching test) and routine formation (in a reversal learning test). Chicks that grew up in larger groups tended to perform less impulsive actions, while social environment did not explain variation in persistence. Chicks from larger groups had less strong routine formation compared to chicks raised in smaller groups. This partially supports the social intelligence hypothesis, and suggest that early social life can affect cognitive traits and explain individual variation in such.
332

Institutional Moderators of the Relationship between College Remediation and Degree Attainment

Shields, Katherine A. January 2014 (has links)
Thesis advisor: Laura M. O'Dwyer / Students who take postsecondary remedial courses graduate from college at lower rates than other students, but the relationship between remedial education and college outcomes is not well understood. This study analyzes the association between remediation and the odds of degree attainment in two- and four-year colleges, after controlling for other student and institutional factors related to persistence. Using generalized multilevel mixed modeling, it examines variation in these relationships across institutional contexts. Data are drawn from the Beginning Postsecondary Students Longitudinal Study (2004/2009), a nationally representative sample that tracked students through interviews and transcript data for six years from their first enrollment. Additional institutional variables are incorporated from the Integrated Postsecondary Education Data System (IPEDS). Comparisons are made among remedial course subjects, higher and lower numbers of remedial courses taken, and different postsecondary credentials. For students who first enroll at a four-year college, this analysis finds that remediation has a negative association with completing a Bachelor's degree or higher, particularly among students who take remedial Mathematics or three or more remedial classes. While students at two-year institutions who take three or more remedial courses have lower odds of completing a certificate or Bachelor's degree, English as a Second Language coursework emerges as a positive factor for Bachelor's attainment in this population. By contrast, remediation has a positive relationship with attaining an Associate's degree but no higher for two-year college students. This relationship varies significantly across two-year institutions, but institutional factors are not predictive of the variation. No other significant cross-college variation is found in the relationships between remedial variables and outcomes. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Lynch School of Education. / Discipline: Educational Research, Measurement and Evaluation.
333

Gender and Migration Background in Intergenerational Educational Mobility. Policy Paper no 11

Schneebaum, Alyssa, Rumplmaier, Bernhard, Altzinger, Wilfried 02 1900 (has links) (PDF)
We employ 2011 European Union Survey on Income and Living Conditions (EU-SILC) data for Austria to perform Markovian mobility matrix analysis and uni- and multivariate econometric analysis to study intergenerational educational mobility by gender and migration background. We find that the educational attainment of girls and migrants relative to their parents is less mobile than for boys and natives. Further, the immobility of educational attainment is enhanced by the intersection of these identities: migrant girls are the least educationally mobile group and are especially likely to follow their mothers 19 educational footsteps, while native boys are the most mobile, especially compared to their mothers. / Series: WWWforEurope
334

Efeitos do isolamento social: sobre a persistência na procura em contextos associados ao álcool / Effects of early social isolation on persistence of alcoholseeking in alcohol-related contexts

Cortes-Patiño, Diana Milena 16 February 2017 (has links)
Experimentos têm mostrado que ratos criados isolados consumem mais álcool durante a idade adulta que ratos criados em condições de interação social; no entanto, poucos experimentos têm explorado os efeitos do isolamento sobre a persistência na procura de álcool. A presente serie de estudos avaliou os efeitos do isolamento em etapas iniciais do desenvolvimento sobre a persistência na procura de álcool em contextos associados à sua entrega. Nos estudos, ratos foram distribuídos imediatamente depois do desmame em duas condições alojamento: isolamento (ISO) e interação (INT). Na idade adulta, os ratos foram treinados em esquemas múltiplos nos quais diferentes contextos de estímulos foram associados a diferentes taxas de entrega de álcool -magnitudes ou a reforçadores diferentes-. A persistência na procura de álcool foi avaliada como resistência à mudança em sessões de extinção. No Capítulo I foi avaliada a persistência em contextos associados a diferentes frequências de entrega de álcool. Foi achado que ratos ISO mostraram maior persistência que ratos INT em contextos associado a frequências altas e baixas de entrega de álcool. No Capítulo II foi estudado o efeito da concentração (5% ou 15%) de álcool sobre a persistência do comportamento de procura. Os resultados mostraram que concentrações altas de álcool geram maior persistência do comportamento de procura, embora gerem taxas baixas de resposta na linha de base. No capítulo III foram realizados dois estudos nos quais foi achado que ratos criados em isolamento persistem mais em contextos associados a concentrações altas de álcool (Experimento 3) e que o isolamento afeta particularmente a procura em contextos associados ao álcool quando comparados com contextos associados a outros reforçadores (Experimento 4). Os achados gerais demonstram que o isolamento em etapas inicias do desenvolvimento incrementa tanto o consumo quanto a persistência na procura por álcool, o que sugere que o estresse social em etapas iniciais do desenvolvimento é um fator de risco para o desenvolvimento de dependência ao álcool / Several experiments have shown increased alcohol consumption in rats reared in social isolation compared to rats reared in group conditions; however, few experiments had explored the effects of social isolation on persistence of alcohol seeking. The studies presented here assessed the effects of social isolation on persistence of seeking in alcoholrelated contexts. For the studies, rats were assigned to on of two conditions after weaning: Social Isolation (ISO) or social Interaction (INT). During adulthood, rats were trained within a multiple schedule of reinforcement, in which different contextual stimuli were related to differential frequencies, magnitudes or qualities of alcohol. Persistence was assessed as resistance to extinction in extinction sessions. Chapter I measured persistence by ISO and INT rats in contexts related to high and low rates of alcohol reinforcement. It was found that ISO rats persisted more than INT rats regardless of the frequency of reinforcement. In Chapter II was studied the effect of alcohol concentration (5% and 15%) on persistence of alcohol seeking. Results showed that high alcohol concentrations are related to higher persistence during extinction. Chapter III presented two studies that found that ISO rats are more persistent in contexts related to high alcohol concentrations (Experiment 3), also that isolation differentially increased persistence in contexts related to alcohol compared to contexts related to other reinforcers (Experiment 4). General findings show that social isolation increase both consumption and persistence in alcohol related contexts, suggesting that social stress early in the development could be a considered a risk factor for alcohol use disorders
335

Atenuação natural de pluma de contaminação de gasolina e etanol em água subterrânea / Natural attenuation of gasoline and ethanol ground water plume

Zoby, José Luiz Gomes 28 July 2006 (has links)
Um estudo de caso e dois experimentos controlados de campo foram realizados, a fim de avaliar o impacto do etanol nos processos de atenuação natural que atuam em plumas de contaminação em fase dissolvida de gasolina. No estudo de caso, foi monitorada uma pluma de contaminação de E22 (gasolina com 22% de etanol em volume) em Itaguaí (RJ). Os dois experimentos controlados foram realizados no aqüífero de Borden, no Canadá, para estudar plumas de E10 e E95 (gasolinas com 10 e 95% de volume de etanol, respectivamente). Neste caso, foram realizadas injeções dos contaminantes abaixo do nível d\'água, gerando plumas que foram monitoradas. O etanol, em subsuperfície, particiona rapidamente para a água subterrânea, deixando a fase residual, e é transportado com a velocidade da água subterrânea. Os outros compostos orgânicos de gasolina migram com velocidades menores. Benzeno e tolueno apresentam velocidades mais próximas do etanol, enquanto trimetilbezenos e naftalenos são os mais retardados. Estas diferenças de migração dos compostos resultaram na separação espacial entre as plumas ao longo do período monitorado. A maior concentração de etanol detectada foi de 12.762 mg/L, que corresponde a um volume de etanol em água de 1,63%. As baixas concentrações de etanol não evidenciam que ele tenha exercido efeito cosolvente pronunciado na solubilidade dos compostos da gasolina. Os compostos orgânicos apresentaram perdas de massa ao longo do tempo de monitoramento. A biodegradação dos contaminantes foi observada pelo consumo de oxigênio dissolvido e metonogênese. O etanol apresentou a maior diminuição de massa e foi biotransformado mesmo sob condições anóxicas. O composto que apresentou a menos perda de massa foi o benzeno. A maior persistência de benzeno é atribuída à sua velocidade de migração próxima à água subterrânea associada ao efeito de consumo preferencial de receptores de elétrons pelo etanol. No estudo de caso, o desaparecimento de etanol pode estar relacionado à sua alta taxa de biodegradação, fato observado nos experimentos de campo. Entretanto, o efeito cosolvente na pluma, que explicaria o deplecionamento dos compostos mais móveis, como benzeno e tolueno, na pluma não foi comprovado nos experimentos. / A case study and two controlled field experiments were conducted to evaluate the impact of ethanol on the natural attenuation processes affecting dissolved phase of gasoline plumes. The case study was conducted in Itaguaí (RJ) where an E22 (gasoline with 22 % by volume of denatured ethanol) contaminant plume was studied. The controlled field experiments were conducted at the Borden aquifer in Canada to study plumes E10 and E95. In this case, contaminants were injected below the water table and plumes were monitored down gradient. In subsurface, ethanol partitions fastly from the residual phase and is transported with the ground water velocity. The other organic compounds migrate with lower velocities. Benzene and toluene present velocities close to ethanol, while trimethylbenzenes and naphthalene are the most retarded. These transport differences resulted in the spatial separation between the plumes throughout the monitoring period. The highest ethanol concentration detected was 12,762 mg/L, which corresponds to 1.63 % of ethanol volume in water. The ethanol concentrations detected do not support the cosolvency effect on the gasoline constituents of the plumes. The organic compounds presented mass losses throughout the monitoring period. Biodegradation was also demonstrated through dissolved oxygen consumption and methanogenesis. Ethanol presented the highest mass losses and was biotransformed under anoxic conditions. Benzene presented the smallest mass loss. Benzene´s higher persistence is related to the migration close to the ground water velocity and the preferential consumption of electron acceptors by ethanol. In the case study, the disappearance of ethanol can be related to its higher biodegradation rate, which was detected through the field experiments. However, the cosolvent effect in the plume, which would explain the depletion of the most mobile compounds such as benzene and toluene was not observed during the field experiments.
336

Teacher and School Contributions to Student Growth

Anderson, Daniel 18 August 2015 (has links)
Teachers and schools both play important roles in students' education. Yet, the unique contribution of each to students' growth has rarely been explored. In this dissertation, a Bayesian multilevel model was applied in each of Grades 3 to 5, with students' growth estimated across three seasonal (fall, winter, spring) administrations of a mathematics assessment. Variance in students' within-year growth was then partitioned into student-, classroom-, and school-level components. The expected differences in students' growth between classrooms and schools were treated as indicators of the teacher or school "effect" on students' mathematics growth. Results provided evidence that meaningful differences in students' growth lies both between classrooms within schools, and between schools. The distribution of teacher effects between schools was also examined through the lens of access and equity with systematic sorting of teachers to schools leading to disproportional student access to classrooms where the average growth was above the norm. Further, previous research has documented persistent and compounding teacher effects over time. Systematic teacher sorting results in students' having differential probabilities of being enrolled in multiple "high" or "low" growth classrooms in a row. While clear evidence of teacher sorting was found, the demographic composition of schools did not relate to the sorting, contrary to previous research. The persistence of teacher and school effects was also examined from a previously unexplored angle by examining the effect of students' previous teacher(s) on their subsequent rate of within-year growth during the school year. These effects were found to be small and teacher effects overall were found to decay quite rapidly.
337

Achromobacter & Pandoraea : diversité et évolution adaptative de populations persistantes au cours de la mucoviscidose et dans l'environnement / Achromobacter & Pandoraea : diversity and adaptive evolution of persistent populations in cystic fibrosis and in environment

Dupont, Chloé 25 November 2016 (has links)
La persistance bactérienne implique une adaptation aux conditions et aux contraintes environnementales, parfois associée à une diversification des génotypes et des phénotypes des populations bactériennes impliquées. Dans le cadre des infections chroniques, la mucoviscidose (CF) est une des pathologies humaines parmi les plus étudiées en termes de persistance et d’adaptation de pathogènes opportunistes. Certains pathogènes opportunistes d’origine environnementale, comme les bactéries des genres Achromobacter et Pandoraea, considérés comme émergents dans cette pathologie, sont capables de coloniser chroniquement les voies respiratoires des patients CF (VRCF). La colonisation et la persistance impliquent des mécanismes d’adaptations étudiés pour P. aeruginosa mais mal connus pour les bactéries émergentes.Nous avons étudié la persistance de bactéries du genre Achromobacter dans les VRCF de 13 patients, ainsi que dans de réseau d’eau d’un centre de soins dentaires, et la persistance de Pandoraea pulmonicola dans les VRCF d’un patient, durant des périodes de colonisation allant jusqu’à 7 ans. En parallèle, nous avons étudié la diversité génomique et phénotypique de populations d’Achromobacter dans les expectorations de 9 patients. Enfin, une investigation environnementale au domicile de 3 patients colonisés chroniquement par Achromobacter a été menée dans le but de connaître la diversité et l’écologie des bactéries de ce genre dans l’environnement proche des patients. Lors de ces différentes études, les espèces d’Achromobacter et Pandoraea ont été identifiées par méthodes moléculaires et la dynamique du génome ainsi que la diversité phénotypique ont été étudiées.Nous avons observé une diversité d’espèces de bactéries du genre Achromobacter colonisant les VRCF, incluant une espèce non décrite. Les patients colonisés chroniquement l’étaient par un clone unique d’Achromobacter ou de P. pulmonicola, appuyant l’idée de l’acquisition initiale d’un clone environnemental qui persiste dans le temps. Une importante diversité génomique et phénotypique a été observée au cours du temps mais aussi au sein de populations à un temps donné. Nous avons également mis en évidence une importante diversité de profils d’antibiorésistance au sein de chaque expectoration, dont l’impact clinique reste à évaluer. Enfin, une diversité d’espèces du genre Achromobacter a été observée au domicile des patients alors que le clone d’A. xylosoxidans adapté aux VRCF des patients n’a pas été isolé dans leurs environnements domestiques. Ces résultats suggèrent qu’après la colonisation initiale et la spécialisation des clones colonisant les VRCF, ceux-ci seraient secondairement incapables de survivre dans l’environnement.Un clone qui colonise les VRCF s’adapte rapidement aux conditions environnementales particulières de cet habitat et subit une diversification génomique et phénotypique intense par spécialisation de génotypes à différentes niches écologiques, aboutissant à une population clonale diversifiée. Cette diversité assure certainement la persistance de la population clonale par "l’hypothèse d’assurance" selon laquelle quelle que soit la pression environnementale exercée, une bactérie ou un sous-groupe de bactéries sera capable d’y résister.Mots clés : Achromobacter, adaptation, colonisation chronique, diversité, écologie, environnement, épidémiologie, évolution, génomique, mucoviscidose, Pandoraea, persistance, phénotype, réseau d’eau, résistance aux antibiotiques. / Bacterial persistence involves adaptation to environmental conditions and constraints, sometimes associated with genotype and phenotype diversification of bacterial populations. In the context of chronic infections, Cystic Fibrosis (CF) is a human disease among the most studied in terms of persistence and adaptation of opportunistic pathogens. Some environmental opportunistic pathogens like Achromobacter and Pandoraea genera are considered as emerging in CF and are able to chronically colonize CF Respiratory Tract (CFRT). Adaptation mechanisms required for colonization and persistence were studied for P. aeruginosa but remain largely unknown for emerging bacteria. We studied Achromobacter spp. persistence in the CFRT of 13 patients and in a dental care unit water network, and Pandoraea pulmonicola persistence in the CFRT of one patient, during colonization periods up to 7 years. In parallel, we studied Achromobacter population genomic and phenotypic diversity in sputum samples from 9 patients. Finally, we made an environmental investigation to study the diversity and the ecology of Achromobacter spp. in household of 3 Achromobacter chronically colonized CF patients. During these studies, Achromobacter and Pandoraea species were identified by molecular methods and genome dynamic and phenotypic diversity were studied.Diversity of Achromobacter species colonizing the CFRT is described and included an undescribed species. Chronically colonized patients had a unique Achromobacter or Pandoraea clone in their CFRT, supporting the initial acquisition of one environmental clone which persists over time. A large genomic and phenotypic diversity has been observed over time and also at the intra-specimen level. A wide antibiotic susceptibility profile diversity was observed within samples and its clinical impact remains to be assessed. Finally, Achromobacter species diversity was observed in patient domestic environment but the Achromobacter clone adapted to the patient CFRT was not isolated. These results suggested that after initial colonization and specialisation the CFRT, colonizing clones might secondarily be unable to survive in the environment.A colonizing clone quickly adapts to the specific local conditions of the CFRT and undergoes intense genomic and phenotypic diversification with genotype specialization to the different ecological niches of the heterogeneous CFRT, resulting in a diversified clonal population. This diversity certainly insures the population persistence according to the “bet hedging” theory stating that regardless of the environmental pressures, a bacteria or a subgroup of bacteria will be able to persist.Key words : Achromobacter, adaptation, antibiotic susceptibility, chronic colonization, Cystic Fibrosis, diversity, ecology, environment, epidemiology, evolution, genomic, Pandoraea, persistence, phenotype, water network.
338

The Grit-to-Graduate: Pedagogical Ideas for Fostering College Persistence, Academic Success, and Career Readiness in Freshmen Through the Basic Communication Course

Lynette J Bleed (6584897) 10 June 2019 (has links)
<p> Students who achieve their long-term goal of graduating from college are models of persistence and grit. Grit is the self-regulatory construct defined as “passion and perseverance for long-term goals despite setbacks, failures, and competing pursuits” (Eskreis-Winkler, Gross, Duckworth, 2016) and has been associated with both academic and workplace success (Eskreis-Winkler, Duckworth, Shulman, & Beal, 2014). Unfortunately, 37% of freshmen drop out of college by the end of their freshmen year (Almeida, 2016; Snyder, de Brey, & Dillow, 2018). The college classroom provides an optimal environment for institutions of higher learning to foster the grit-to-graduate<i> </i>in college freshmen, to enhance learning and academic success, and to increase goal commitment to graduation, degree achievement, and career readiness.</p> <p> The purpose of this study was to investigate whether six pedagogical interventions and project adaptations would increase student grit in an entry-level communication class heavily comprised of freshmen. Four class sections were administered the 12-item grit scale (Duckworth, 2019) during the first and last week of first semester at a Midwestern University (<i>N</i>=79). The experimental group received the pedagogical grit interventions throughout the semester; the control group did not. A repeated measures ANOVA computed the variance of grit scores between the groups. Students in the experimental group also provided quantitative and qualitative data about which pedagogical instruments they found most effective.</p> <p> While the hypothesis was not supported, student feedback on the six grit interventions was largely positive. Ideas for improving the interventions and for fostering grit and college persistence in freshmen are included.</p> <br>
339

Diamonds are forever long-run effects of mining institutions in Brazil / Os diamantes são eternos: efeitos de longo prazo de instituições mineradoras no Brasil

Carvalho, Marcelo Sacchi de 02 August 2016 (has links)
This paper uses a regression discontinuity approach to investigate whether a set of colonial policies adopted in the Diamond District have long-run impacts on development. Results show that the treatment effect is positive on household income, adult literacy and light density from satellite images. I also explore potential channels through which this historical event might be leading to these positive outcomes. I use contemporary census data to show that treated areas have higher urbanization rates. I also present evidence from 1872 and 1890 census data that areas inside the District have persistently higher human capital levels. Using a geospatial road location database and vector data constructed from historical maps, I find that observations inside the District\'s historical boundaries used to have less dense road networks but this is not true today. Additionally I use data from the 1830s and from the 1872 census to show that slavery was more intense in treated villages but after the decline of diamond extraction this difference vanished / Este artigo usa a técnica de regressão descontínua para investigar se um conjunto de políticas coloniais adotado no Distrito Diamantino tem efeitos de longo prazo sobre o desenvolvimento econômico. Os resultados mostram que o tratamento tem efeito positivo sobre renda por domicílio, alfabetização de adultos e densidade de luz obtida através de imagens de satélite. Eu também exploro potenciais canais de transmissão através dos quais esse evento histórico poderia gerar esses resultados positivos Eu uso dados do Censo de 2010 para mostrar que áreas tratadas têm taxa de urbanização mais alta. Eu também apresento evidência a partir dos Censos de 1872 e 1890 de que área dentro do Distrito tinham nível de capital humano persistentemente mais alto. Usando uma base geoespacial de localização de estradas e dados vetoriais construídos a partir de mapas históricos, eu encontro que observações dentro dos limites históricos do Distrito tinham redes viárias menos densas originalmente, mas que isso não é verdade hoje em dia. Adicionalmente, eu uso dados dos anos 1830 e do Censo de 1872 para mostrar que havia mais escravidão em paróquias tratadas, mas que com o declínio da extração dos diamantes essa diferença desapareceu.
340

Persistência de palhada de plantas de cobertura em função de doses de silício e resposta do feijoeiro em sucessão /

Fernandes, Fabiana Aparecida, 1982- January 2008 (has links)
Orientador: Leonardo Theodoro Büll / Banca: CarlosAlexandre Costa Crusciol / Banca: Takashi Muraoka / Resumo: A manutenção dos resíduos vegetais na superfície do solo é essencial para a sustentabilidade do sistema plantio direto, para tanto, é fundamental a seleção de coberturas vegetais com elevada capacidade de produção de massa seca, principalmente, em regiões onde as condições climáticas são favoráveis à rápida decomposição, além do estabelecimento de manejos da palhada que minimizem esse efeito, visando à proteção superficial do solo, formação de palhada, bem como reciclagem de nutrientes, com impacto direto nos atributos químicos do solo e na resposta das culturas subseqüentes ou em rotação. Assim o objetivo do trabalho foi avaliar a persistência da palhada de espécies de cobertura em função da aplicação de silicato e calcário e a resposta da cultura do feijão em sucessão em semeadura direta. O delineamento experimental utilizado foi em blocos ao acaso disposto em um esquema fatorial 3x5, com quatro repetições. O trabalho foi desenvolvido em estufa, no Departamento de Produção Vegetal, pertencente à Faculdade de Ciências Agronômicas - UNESP, Campus Botucatu. As parcelas foram constituídas por cinco doses de silicato de cálcio, calculadas em função da quantidade necessária para elevar a saturação por bases a 70%, dispostas da seguinte forma: 1 - 0 de silicato cálcio e 100% de calcário; 2 - 25% de silicato de cálcio e 75% de calcário; 3 - 50% de silicato de cálcio e 50% de calcário; 4 - 75% de silicato de cálcio e 25% de calcário; 5 - 100% de ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The maintenance of residual vegetation on the surface of the soil is essential for the sustainability no till, therefore, is essential the selection of covering vegetation with an increase capacity for the production of dry mass, especially in regions where climate conditions are favorable for rapid decomposition, along with establishing ways to handle the ground cover to minimize this effect, aiming for the protection of the soil surface, ground cover formation, as well as nutrients recycling, with direct impact on chemical properties of the soil and on response to subsequent or rotation crop. Therefore, the objective of the research was to evaluate the continued usage of the ground cover species as in function of the correction of the soil with silicate and lime and the response of the beans crop in succession in the direct plantation system. The experimental outlined used was the random blocks arranged in a 3x5 factorial design, with four replication. The experiment was developed in greenhouse, in the Department of Agriculture, of the Faculdade de Ciências Agronômicas - FCA - UNESP, Campus Botucatu. The plots were composed by five doses of calcium silicate, calculated as a function of the quantity necessary to increase base saturation to 70%, arranged as follows: 1 - 0% calcium silicate and 100% lime; 2 - 25% calcium silicate and 75% lime; 3 - 50% calcium silicate and 50% lime; 4 - 75% calcium silicate and 25% lime; 5 - 100% calcium silicate and 0% lime and three species of cover crops: millet (Pennisetum americanum L) beard grass (Brachiaria brizantha) pigeon pea (Cajanus cajan L.). The lime used was a mixture of CaCO3 and MgCO3 PA, so as to obtain the same proportions of Ca and Mg, both in the lime and in the silicate, this way varying, only the silicon content in each treatment. The parameters analyzed were: content and accumulation of nutrients ...(Complete abstract, click electronic access below) / Mestre

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