18,028 research outputs found
Carnivory in Adult Female Eumenid Wasps (Hymenoptera: Vespidae: Eumeninae) and Its Effect on Egg Production
Seventy captive adult female wasps of the eumenid genera Ancistrocerus and Euodynerus were observed to feed on multiple prey items. It was shown experimentally that E. foraminatus females that fed on prey had significantly larger egg volumes than adult wasps deprived of prey
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Direct Measurement of Vanadium Crossover in an Operating Vanadium Redox Flow Battery
Measurements of Vanadium diffusion coefficients for transport across cation exchange membranes using dialysis cells have been reported in the literature. However, to date direct measurement of crossover coefficients in an operating Vanadium redox flow battery (VRB) cell have not been reported. Results are reported in this paper on experiments utilizing a special VRB cell which allows measurement of Vanadium ion transport across ion exchange membranes with and without the presence of current. The cell utilizes two additional flow regions which collect Vanadium ions which diffuse from the positive and negative half cells. The effects of the magnitude and direction of electrical current on transport can be measured directly with this cell. We observe that transport is greatly enhanced when the direction of the hydrogen ion flux is in the same direction as the density gradient driven vanadium flux and suppressed when the hydrogen ion flux is in the opposite direction. The cell has been used to of investigate the effects on transport of current densities up to 900 mA/cm(2).US Department of Energy ARPA-E program DE-AR00000149Materials Science and Engineerin
Methods for Artificial Rearing of Solitary Eumenid Wasps (Hymenoptera: Vespidae: Eumeninae)
Solitary eumenid wasps of the genera Ancistrocerus and Euodynerus can be reared in small cages. Laboratory-reared larvae of the spruce budworm caterpillars, Choristoneura fumiferana (Lepidoptera: Torlricidae) are suitable prey
Order theory and interpolation in operator algebras
We continue our study of operator algebras with and contractive approximate
identities (cais). In earlier papers we have introduced and studied a new
notion of positivity in operator algebras, with an eye to extending certain
C*-algebraic results and theories to more general algebras. Here we continue to
develop this positivity and its associated ordering, proving many foundational
facts. We also give many applications, for example to noncommutative topology,
noncommutative peak sets, lifting problems, peak interpolation, approximate
identities, and to order relations between an operator algebra and the
C*-algebra it generates. In much of this it is not necessary that the algebra
have an approximate identity. Many of our results apply immediately to function
algebras, but we will not take the time to point these out, although most of
these applications seem new.Comment: 27 pages. arXiv admin note: substantial text overlap with
arXiv:1308.272
Ideals and hereditary subalgebras in operator algebras
This paper may be viewed as having two aims. First, we continue our study of
algebras of operators on a Hilbert space which have a contractive approximate
identity, this time from a more Banach algebraic point of view. Namely, we
mainly investigate topics concerned with the ideal structure, and hereditary
subalgebras (HSA's), which are in some sense generalization of ideals. Second,
we study properties of operator algebras which are hereditary subalgebras in
their bidual, or equivalently which are `weakly compact'. We also give several
examples answering natural questions that arise in such an investigation.Comment: 24 page
Intramolecular integration within Moloney murine leukemia virus DNA
By screening a library of unintegrated, circular Moloney murine leukemia virus (M-MuLV) DNA cloned in lambda phage, we found that approximately 20% of the M-MuLV DNA inserts contained internal sequence deletions or inversions. Restriction enzyme mapping demonstrated tht the deleted segments frequently abutted a long terminal repeat (LTR) sequence, whereas the inverted segments were usually flanked by LTR sequences, suggesting that many of the variants arose as a consequence of M-MuLV DNA molecules integrating within their own DNA. Nucleotide sequencing also suggested that most of the variant inserts were generated by autointegration. One of the recombinant M-MuLV DNA inserts contained a large inverted repeat of a unique M-MuLV sequence abutting an LTR. This molecule was shown by nucleotide sequencing to have arisen by an M-MuLV DNA Molecule integrating within a second M-MuLV DNA molecule before cloning. The autointegrated M-MuLV DNA had generally lost two base pairs from the LTR sequence at each junction with target site DNA, whereas a four-base-pair direct repeat of target site DNA flanked the integrated viral DNA. Nucleotide sequencing of preintegration target site DNA showed that this four-base-pair direct repeat was present only once before integration and was thus reiterated by the integration event. The results obtained from the autointegrated clones were supported by nucleotide sequencing of the host-virus junction of two cloned M-MuLV integrated proviruses obtained from infected rat cells. Detailed analysis of the different unique target site sequences revealed no obvious common features
Study of utraslow atomic motions by magnetic resonance
Journal ArticleMagnetic resonance has been widely used to study phenomena such as atomic diffusion and molecular reorientation. It is applicable when the mean time, r, between atomic jumps is either (a) sufficiently short to narrow the resonance line width or (b) of the correct magnitude to produce spin-lattice relaxation. Case (a) occurs when r is less than 1/Aco where Au> is the rigid lattice linewidth. Case (b) occurs when T is of the order of l/co0 , where oo0 is the Larmor frequency. Typically, case (a) is found when r < 100 /isec, case (b) when r ~ 10 ~ 8 sec. In this Letter we report a new, experimentally simple technique which enables us to study motions of a much slower rate, the criterion being roughly T < T 1 where T1 is the spin-lattice relaxation time
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