13,075 research outputs found
Conhecendo espécies de plantas da Amazônia: ingá-costela (Inga capitata desv. - Leguminosae).
bitstream/item/102979/1/COM-TEC-243.pd
Fluorescência da clorofila em plantas de cambre submetidas a sub-doses do herbicida sulfentrazone.
What are the Best Hierarchical Descriptors for Complex Networks?
This work reviews several hierarchical measurements of the topology of
complex networks and then applies feature selection concepts and methods in
order to quantify the relative importance of each measurement with respect to
the discrimination between four representative theoretical network models,
namely Erd\"{o}s-R\'enyi, Barab\'asi-Albert, Watts-Strogatz as well as a
geographical type of network. The obtained results confirmed that the four
models can be well-separated by using a combination of measurements. In
addition, the relative contribution of each considered feature for the overall
discrimination of the models was quantified in terms of the respective weights
in the canonical projection into two dimensions, with the traditional
clustering coefficient, hierarchical clustering coefficient and neighborhood
clustering coefficient resulting particularly effective. Interestingly, the
average shortest path length and hierarchical node degrees contributed little
for the separation of the four network models.Comment: 9 pages, 4 figure
Fluorescência da clorofila A em plantas de nabo forrageiro submetidas à subdoses do herbicida S-metolachlor.
Conhecendo espécies de plantas da Amazônia: ingá-vermelha [Inga alba (Sw.) Willd. - Leguminosae - Mimosoideae].
bitstream/item/99944/1/COM-242.pd
Responses in growth and dynamics of the shade-tolerant species Theobroma subincanumto logging gaps in the Eastern Amazon.
Aim of study: To assess responses of the shade-tolerant species Theobroma subincanum in relation to canopy gaps created by reduced impact logging (RIL). Materials and methods: A managed forest in themunicipality ofMoju, Pará state,Brazil, harvested in 1997 through RIL was monitored during 12 years (1998-2010). Nine logging gaps were selected and classified in small, medium, and large. Four 10 m x 50 m strips starting from the gap?s border towards the forest and following the directions of cardinal points were installed. Each strip was divided in five 10 m x 10 m plots. Density, diameter distribution (DBH ≥ 5 cm with intervals = 5 cm), and diameter growth were measured. Main results: No significant changes in seedling density of T. subincanum were found, and its diameter distribution followed the reverse ?J? shape during all monitoring time. T. subincanum presented diameter growth of 0.15 cm year-1 with highest Periodic Annual Increment in diameter up to three years, and stabilization in nine years after RIL. The species responded to a growth gradient inversely proportional to the gap?s border distance (p = 0.001) but not to gap size and plots direction in cardinal points around the gap. Research highlights: Shade-tolerant species such as T. subincanum have sensible and positive growth responses to disturbances caused by RIL even when seedlings received low amounts of indirect sunlight. These positive responses should be considered in the management of production forests
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