2,512 research outputs found
Analysis of existing mathematics textbooks for use in secondary schools.
Thesis (Ed.M.)--Boston University
Thesis (M.A.)--Boston Universit
Diel interactions between prey behaviour and feeding in an invasive fish, the round goby, in a North American river
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72558/1/j.1365-2427.2006.01527.x.pd
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Spectroscopic investigations of the electronic structure of neptunyl ions.
Molecular electronic structures are innately sensitive to the geometric and chemical environments around the metal center of coordination compounds . However, the interrelationships between the electronic structures and molecular geometries of actinide species, which often contain more than one electron in the Sf valence shell, are quite complex due to the large numbers of possible electronic states and high densities of vibronically enabled transitions .1'2 Investigations of the optical signatures of simple, well-defined molecular systems should provide the most straightforward approach for unharnessing these fundamental relationships, and in particular, systems with a single electron in the valence Sf shell, such as the neptunyl ion (Np0 22+), should provide the most viable means for characte rizing actinide electronic structure. Furthermore, Sf orbital-occupied actinide systems exhibit not only visible and ultraviolet ligand-to-metal charge-transfer spectral bands, but also near-infrared Sf-Sf transitions resulting from promotion of a Sf electron to an orbital of primarily Sf character
Proof of Bose-Einstein Condensation for Interacting Gases with a One-Particle Spectral Gap
Using a specially tuned mean-field Bose gas as a reference system, we
establish a positive lower bound on the condensate density for continuous Bose
systems with superstable two-body interactions and a finite gap in the
one-particle excitations spectrum, i.e. we prove for the first time standard
homogeneous Bose-Einstein condensation for such interacting systems
Responses of parasitoids to volatiles induced by Chilo partellus oviposition on teosinte, a wild ancestor of maize
Maize, a genetically diverse crop, is the domesticated
descendent of its wild ancestor, teosinte. Recently, we
have shown that certain maize landraces possess a valuable
indirect defense trait not present in commercial hybrids. Plants of these landraces release herbivore-induced plant volatiles (HIPVs) that attract both egg [Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae)and larval [Cotesia sesamiae Cameron (Hymenoptera:Braconidae)] parasitoids in response to stemborer egg deposition.
In this study, we tested whether this trait also exists in the germplasm of wild Zea species. Headspace samples were collected from plants exposed to egg deposition by Chilo
partellus Swinhoe (Lepidoptera: Crambidae) moths and unexposed control plants. Four-arm olfactometer bioassays with parasitic wasps, T. bournieri and C. sesamiae, indicated that both egg and larval parasitoids preferred HIPVs from plants with eggs in four of the five teosinte species sampled.
Headspace samples from oviposited plants released higher
amounts of EAG-active compounds such as (E)-4,8-dimethyl-
1,3,7-nonatriene. In oviposition choice bioassays, plants
without eggs were significantly preferred for subsequent oviposition by moths compared to plants with prior oviposition.
These results suggest that this induced indirect defence trait is not limited to landraces but occurs in wild Zea species and appears to be an ancestral trait. Hence, these species possess a valuable trait that could be introgressed into domesticated maize lines to provide indirect defense mechanisms against stemborers
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