A review of the stable isotope bio-geochemistry of the global silicon cycle and its associated trace elements

Silicon (Si) is the second most abundant element in the Earth’s crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry (e.g., Al/Si, Ge/Si, Zn/Si, d13C, d15N, d18O, d30Si) of dissolved and biogenic Si, present case studies, such as the Silicic Acid Leakage Hypothesis, and discuss challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e., sources, sinks, and processes) and the potential technical and conceptual limitations that need to be considered for future studies

Approach of migration since curriculum and didactic unification in São Paulo state schools

Este trabalho tem como objetivo principal entender como as migrações são apresentadas e desenvolvidas nas apostilas de professores e alunos da rede estadual de São Paulo, desde a introdução de currículo e material unificado em 2008. As mudanças que a escola paulista sofreu desde essa data fazem parte de uma política educacional neoliberal adotada pelo governo estadual de São Paulo que sofre influências de instituições financeiras internacionais, como o Banco Mundial, que relaciona desenvolvimento econômico ao ensino. Para tanto, avaliamos tais materiais conforme nossas considerações e experiências vivenciadas dentro da sala de aula e também pelos critérios de avaliação de livros didáticos do Programa Nacional do Livro Didático (PNLD). Além das avaliações das migrações nos materiais didáticos unificados, serão também discutidas as influências internacionais no ensino de São Paulo; a formação do aluno conforme os interesses internacionais; as consequências sofridas por alunos, professores e pela escola; o currículo unificado de Geografia implantado em 2008; a utilização das apostilas em sala de aula; a nova função do professor, entre outros, que se relacionam às expectativas e a atual realidade do ensino paulista.This work has as main objective to comprehend how migrations concepts are presented and developed in the São Paulo state schools textbooks, since the introduction of the unified curriculum and didactic material in 2008. The changes that schools underwent since 2008 are part of a neoliberal educational policy adopted by São Paulo state government, which is influenced by international financial institutions, such as World Bank, that link economic development to education. For that, we evaluated the textbooks following our considerations, based both on our own experiences in classrooms and on the evaluation criteria of the Textbook National Program (Programa Nacional do Livro Didático PNLD). In addition to evaluating migration in the textbooks, we will also discuss the international influences on São Paulo education; the student education following international interests; the consequences suffered by students, teachers and the school; the curriculum of Geography adopted in 2008; the use of textbooks in the classroom; the new role of teachers; among others, which are related to the expectations and current reality of teaching in São Paulo

Functional Evolution of Young Retrogenes with Regulatory Roles in Drosophila

The set of genes in the genome of a species is the result of a dynamic net balance between gain and loss events that happen over evolutionary time. The origination and divergence of new genes are major sources of genomic novelty, and has the potential to generate substantial raw material for the evolution of functional innovations. It has been recently recognized that young genes can take over fundamental functions in basic cellular processes and be essential for the survival of an organism, even when they are restricted to a few species in a phylogeny. It is not clear, however, how newly duplicated genes are integrated into ancestral networks or to what extent they diverge from their parents at the functional level. In the two study cases reported here, I investigate the evolution of three relatively young duplicated genes with regulatory functions, and only found in some fly species. Using computational analyses and experimental assays, I show that a diverse suite of factors was responsible for the functional divergence of the duplicated genes after their origination from their conserved parental genes. After their origination through retrotransposition events in different branches of the Drosophila phylogeny, the genes acquired a restrict expression pattern, and rapidly diverged in sequence from their parents, which remained essentially conserved. I further show their phenotypic importance for viability and male fertility, and demonstrate that the duplicated genes diverged in several aspects from their parents, including their protein interactions, genomic binding pattern and impact on global gene regulation. Our results show how young elements can be integrated into conserved processes in different ways, and illustrate the complex nature of evolution driven by new gene origination

ABORDAGEM DO TEMA “MIGRAÇÃO” NAS APOSTILAS DA REDE PÚBLICA ESTADUAL PAULISTA

Dentre os tantos assuntos estudados na disciplina de Geografia da rede pública estadual paulista, os fluxos migratórios se caracterizam por serem importantes, pois estão muito presentes no cotidiano do aluno: ao se deslocar de casa até a escola; da migração de seus pais de um estado até outro ou ainda de amigos que foram para outro país em busca de emprego, por exemplo. Por isso, esse assunto merece destaque em sala de aula e assim, se faz necessário, juntamente com o professor, um bom material de apoio: jornais, documentários, filmes, revistas, livros didáticos, apostilas e outros. Portanto, objetivamos analisar de que forma as apostilas de Geografia organizadas pela Secretaria de Educação do Estado de São Paulo apresentam os conteúdos relacionados aos processos migratórios. Para tanto, os materiais que apresentam tal assunto serão selecionadas e itens como: ilustrações, representações cartográficas, textos, exercícios, dentre outros, serão analisados para que posteriormente possamos contribuir para melhora do material. Como exemplo dessa análise, podemos citar o mapa “As Migrações, final do século XX” página 23 do caderno do aluno, volume 1, 3ª série do Ensino Médio, que ao apresentar os principais fluxos migratórios internacionais aponta apenas um questionamento aos alunos: “O que o mapa representa? Justifique”. Tal mapa com informações sobre efetivo de imigrantes, fluxos e porcentagem de imigrantes na população, poderia ser mais explorado em questões e discussões para melhor compreensão do aluno

Prevalence and male-killing effect of Spiroplasma endosymbiont in Drosophila melanogaster populations

Orientador: Louis Bernard KlaczkoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O resumo poderá ser visualizado no texto completo da tese digitalAbstract: The abstract is available with the full electronic documentMestradoGenetica Animal e EvoluçãoMestre em Genética e Biologia Molecula

Screening for male-killing variation among Drosophila melanogaster and Spiroplasma strains

This file contains 5 spreadsheets with experimental data of screening for male-killing variation among Drosophila melanogaster and Spiroplasma strains, at 18.5 and 23ºC

Data from: Low temperature reveals genetic variability against male-killing Spiroplasma in Drosophila melanogaster natural populations

Spiroplasma endosymbionts are maternally inherited microorganisms which infect many arthropod species. In some Drosophila species, it acts as a reproductive manipulator, spreading in populations by killing the sons of infected mothers. Distinct Drosophila melanogaster populations from Brazil exhibit variable male-killing Spiroplasma prevalences. In this study, we investigated the presence of variability for the male-killing phenotype among Drosophila and/or Spiroplasma strains and verified if it correlates with the endosymbiont prevalence in natural populations. For that, we analyzed the male-killing expression when Spiroplasma strains from different populations were transferred to a standard D. melanogaster line (Canton-S) and when a common Spiroplasma strain was transferred to different wild-caught D. melanogaster lines, both at optimal and challenging temperatures for the bacteria. No variation was observed in the male-killing phenotype induced by different Spiroplasma strains. No phenotypic variability among fly lines was detected at optimal temperature (23 °C), as well. Conversely, significant variation in the male-killing expression was revealed among D. melanogaster lines at 18.5 °C, probably caused by imperfect transmission of the endosymbiont. Distinct lines differed in their average sex ratios as well as in the pattern of male-killing expression as the infected females aged. Greater variation occurred among lines from one locality, although there was no clear correlation between the male-killing intensity and the endosymbiont prevalence in each population. Imperfect transmission or male killing may also occur in the field, thus helping to explain the low or intermediate prevalences reported in nature. We discuss the implications of our results for the dynamics of male-killing Spiroplasma in natural populations