8,339 research outputs found
Fish, Corumbataí and Jacaré-Pepira river basins, São Paulo State, Brazil
Fish were studied in two river basins (Corumbataí and Jacaré-Pepira) subjected to strong human pressure, in the interior of the State of São Paulo, southeastern Brazil. In the Corumbataí basin, four sites were sampled: Cabeça river, Lapa stream, Passa-Cinco river, and Corumbataí river; in the Jacaré-Pepira basin, three sites were sampled: Tamanduá stream, Jacaré-Pepira river, and Água Branca stream. A total of 4,050 specimens belonging to 48 species and 13 families were caught and analyzed
Células de inovação : experiências educacionais em CTS+I
Neste artigo pretende-se mostrar uma investigação que vem sendo feita em escolas de formação profissional brasileiras com o uso de Células de Inovação (CI). As CI's são grupos de estudantes envolvidos com a tarefa de solucionar um problema concreto da de sua escola ou bairro utilizando-se de conhecimentos técnico-científicos. Procurou-se investigar, através de uma metodologia etnográfica, como esses alunos aprendem os conteúdos de ciência ao solucionar seu problema e se a inovação é algo que possa ser aprendido. As situações trabalhados são problematizadas numa perspectiva CTS e, em seguida, são discutidas soluções. A implementação das melhores soluções gera nova discussão CTS sobre seu impacto. O trabalho aqui descrito cobre apenas uma célula. Pretende-se que a partir de 2010 que a investigação estenda-se para várias células trabalhando em rede
Análises patentométrica, bibliométrica e do portfólio de projetos da Embrapa relacionados a Elaeis sp.
bitstream/item/79835/1/CITE-12.pd
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Oxidative stress specifically downregulates survivin to promote breast tumour formation.
BackgroundBreast cancer, a heterogeneous disease has been broadly classified into oestrogen receptor positive (ER+) or oestrogen receptor negative (ER-) tumour types. Each of these tumours is dependent on specific signalling pathways for their progression. While high levels of survivin, an anti-apoptotic protein, increases aggressive behaviour in ER- breast tumours, oxidative stress (OS) promotes the progression of ER+ breast tumours. Mechanisms and molecular targets by which OS promotes tumourigenesis remain poorly understood.ResultsDETA-NONOate, a nitric oxide (NO)-donor induces OS in breast cancer cell lines by early re-localisation and downregulation of cellular survivin. Using in vivo models of HMLE(HRAS) xenografts and E2-induced breast tumours in ACI rats, we demonstrate that high OS downregulates survivin during initiation of tumourigenesis. Overexpression of survivin in HMLE(HRAS) cells led to a significant delay in tumour initiation and tumour volume in nude mice. This inverse relationship between survivin and OS was also observed in ER+ human breast tumours. We also demonstrate an upregulation of NADPH oxidase-1 (NOX1) and its activating protein p67, which are novel markers of OS in E2-induced tumours in ACI rats and as well as in ER+ human breast tumours.ConclusionOur data, therefore, suggest that downregulation of survivin could be an important early event by which OS initiates breast tumour formation
Dengue disease, basic reproduction number and control
Dengue is one of the major international public health concerns. Although
progress is underway, developing a vaccine against the disease is challenging.
Thus, the main approach to fight the disease is vector control. A model for the
transmission of Dengue disease is presented. It consists of eight mutually
exclusive compartments representing the human and vector dynamics. It also
includes a control parameter (insecticide) in order to fight the mosquito. The
model presents three possible equilibria: two disease-free equilibria (DFE) and
another endemic equilibrium. It has been proved that a DFE is locally
asymptotically stable, whenever a certain epidemiological threshold, known as
the basic reproduction number, is less than one. We show that if we apply a
minimum level of insecticide, it is possible to maintain the basic reproduction
number below unity. A case study, using data of the outbreak that occurred in
2009 in Cape Verde, is presented.Comment: This is a preprint of a paper whose final and definitive form has
appeared in International Journal of Computer Mathematics (2011), DOI:
10.1080/00207160.2011.55454
Aspectos históricos do bicudo do algodoeiro (Anthonomus grandis Baheman).
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