Conservação das sementes de Pinheiro-do-Paraná (Araucaria angustifolia Bert.O.Ktze.)

Edição dos resumos do 18º Congresso Brasileiro de Sementes, 2013, Florianópolis. CD-ROM

On the Nature of Precursors in the Radio Pulsar Profiles

In the average profiles of several radio pulsars, the main pulse is accompanied by the preceding component. This so called precursor is known for its distinctive polarization, spectral, and fluctuation properties. Recent single-pulse observations hint that the sporadic activity at the extreme leading edge of the pulse may be prevalent in pulsars. We for the first time propose a physical mechanism of this phenomenon. It is based on the induced scattering of the main pulse radiation into the background. We show that the scattered component is directed approximately along the ambient magnetic field and, because of rotational aberration in the scattering region, appears in the pulse profile as a precursor to the main pulse. Our model naturally explains high linear polarization of the precursor emission, its spectral and fluctuation peculiarities as well as suggests a specific connection between the precursor and the main pulse at widely spaced frequencies. This is believed to stimulate multifrequency single-pulse studies of intensity modulation in different pulsars.Comment: 5 pages, no figures. Accepted for publication in MNRAS Letter

A influência do manejo do solo e da calagem na intensidade do mal-do-pe do trigo.

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Dormência em sementes florestais.

Categorias de dormencia; dormencia tegumentar ou exogena, dormencia embrionaria ou endogena; Causas da dormencia; Metodos para a superacao da dormencia; Dormencia combinadabitstream/item/153708/1/doc40.pd

Contamination

Soil contamination occurs when substances are added to soil, resulting in increases in concentrations above background or reference levels. Pollution may follow from contamination when contaminants are present in amounts that are detrimental to soil quality and become harmful to the environment or human health. Contamination can occur via a range of pathways including direct application to land and indirect application from atmospheric deposition. Contamination was identified by SEPA (2001) as a significant threat to soil quality in many parts of Scotland. Towers et al. (2006) identified four principal contamination threats to Scottish soils: acidification; eutrophication; metals; and pesticides. The Scottish Soil Framework (Scottish Government, 2009) set out the potential impact of these threats on the principal soil functions. Severe contamination can lead to “contaminated land” [as defined under Part IIA of the Environmental Protection Act (1990)]. This report does not consider the state and impacts of contaminated land on the wider environment in detail. For further information on contaminated land, see ‘Dealing with Land Contamination in Scotland’ (SEPA, 2009). This chapter considers the causes of soil contamination and their environmental and socio-economic impacts before going on to discuss the status of, and trends in, levels of contaminants in Scotland’s soils

Testes de envelhecimento precoce para sementes de bracatinga (Mimosa scabrella Benth).

O trabalho objetiva determinar as melhores temperaturas e tempos de exposição dentro da camara para a realização do teste de envelhecimento precoce de sementes de Bracatinga (Mimosa scabrella Benth).bitstream/item/96269/1/CPAF-AP-2000-Teste-Bracatinga.pd

Manejo de sementes de espécies florestais.

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Quebra de dormência e armazenamento de sementes de Erythrina crista-galli L.

Resumo 6