78 research outputs found
Benefits of Entomophile Pollination in Crops of Brassica napus and Aspects of Plant Floral Biology
Rapeseed (Brassica napus L. var. oleifera) is an oleaginous species of the Brassicaceae family, being the third most produced oleaginous in the world. Rapeseed can produce fruits and seeds from both self-pollination and cross-pollination. However, cross-pollination rate is approximately 30% and may suffer variations due to the abundance and diversity of pollinator insects, cultivar and meteorological conditions. Different researchers have reported that pollination by insects, especially Apis mellifera honeybee, on rapeseed flowers provides an increase in productivity, improving yield and contributing to the uniformity and initial pod establishment. It is estimated that the economic value of A. mellifera honeybees for rapeseed cultivation in Brazil is US$ 8.2 million. The objective of this chapter is gathering data for a compilation of information regarding rapeseed culture and the importance of A. mellifera in Brassica napus pollination
Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions
We study the beam-energy and system-size dependence of \phi meson production
(using the hadronic decay mode \phi -- K+K-) by comparing the new results from
Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4
and 200 GeV measured in the STAR experiment at RHIC. Data presented are from
mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the
transverse momentum distributions for \phi mesons are observed to be similar in
yield and shape for Cu+Cu and Au+Au colliding systems with similar average
numbers of participating nucleons. The \phi meson yields in nucleus-nucleus
collisions, normalised by the average number of participating nucleons, are
found to be enhanced relative to those from p+p collisions with a different
trend compared to strange baryons. The enhancement for \phi mesons is observed
to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations
for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision
energies, the source of enhancement of strange hadrons is related to the
formation of a dense partonic medium in high energy nucleus-nucleus collisions
and cannot be alone due to canonical suppression of their production in smaller
systems.Comment: 20 pages and 5 figure
- …