1,468 research outputs found
The potential use of lures for thrips biological control in greenhouses: practice and theory
Exploiting the response of thrips pest species to odours has long been a goal for improving thrips pest management including biological control. Applications of attractants could include improved monitoring, push-pull (in conjunction with a repellent odour), lure and kill, and lure and infect technologies, and surveillance for invasive organisms. We have recently discovered that 4-pyridyl carbonyl compounds can elicit responses from a range of thrips species (Thrips tabaci, T. major, T. obscuratus and Frankliniella occidentalis) in the laboratory, in glasshouses and in open field bioassays. Some of these compounds can increase the trap capture of these thrips species in both commercial greenhouses and broad acre commercial crops where these species are considered pests. However, our understanding of the mechanisms eliciting this response in thrips is still only rudimentary. Greater knowledge of the underlying behavioural mechanisms, including the intrinsic and extrinsic factors that may affect these responses, as well as optimal trap design and configuration, and odour formulation, will be essential if semiochemical-based approaches are to be integrated into thrips management programme
In search for classification and selection of spare parts suitable for additive manufacturing: a literature review
This paper reviews the literature on additive manufacturing (AM) technologies and equipment, and spare parts classification criteria to propose a systematic process for selecting spare parts which are suitable for AM. This systematic process identifies criteria that can be used to select spare parts that are suitable for AM. The review found that there is limited research that addresses identifying processes for spare parts selection for AM, even though companies have identified this to be a key challenge in adopting AM. Seven areas for future research are identified relating to the methodology of spare parts selection for AM, processes for cross-functional integration in selecting spare parts for AM, broadening the spare parts portfolio that is suitable for AM (by considering usage of AM in conjunction with conventional technologies), and potential impact of AM on product modularity and integrality
Protecting Quantum Information with Entanglement and Noisy Optical Modes
We incorporate active and passive quantum error-correcting techniques to
protect a set of optical information modes of a continuous-variable quantum
information system. Our method uses ancilla modes, entangled modes, and gauge
modes (modes in a mixed state) to help correct errors on a set of information
modes. A linear-optical encoding circuit consisting of offline squeezers,
passive optical devices, feedforward control, conditional modulation, and
homodyne measurements performs the encoding. The result is that we extend the
entanglement-assisted operator stabilizer formalism for discrete variables to
continuous-variable quantum information processing.Comment: 7 pages, 1 figur
Addressing the clumsiness loophole in a Leggett-Garg test of macrorealism
The rise of quantum information theory has lent new relevance to experimental
tests for non-classicality, particularly in controversial cases such as
adiabatic quantum computing superconducting circuits. The Leggett-Garg
inequality is a "Bell inequality in time" designed to indicate whether a single
quantum system behaves in a macrorealistic fashion. Unfortunately, a violation
of the inequality can only show that the system is either (i)
non-macrorealistic or (ii) macrorealistic but subjected to a measurement
technique that happens to disturb the system. The "clumsiness" loophole (ii)
provides reliable refuge for the stubborn macrorealist, who can invoke it to
brand recent experimental and theoretical work on the Leggett-Garg test
inconclusive. Here, we present a revised Leggett-Garg protocol that permits one
to conclude that a system is either (i) non-macrorealistic or (ii)
macrorealistic but with the property that two seemingly non-invasive
measurements can somehow collude and strongly disturb the system. By providing
an explicit check of the invasiveness of the measurements, the protocol
replaces the clumsiness loophole with a significantly smaller "collusion"
loophole.Comment: 7 pages, 3 figure
Experimental implementation of a NMR entanglement witness
Entanglement witnesses (EW) allow the detection of entanglement in a quantum
system, from the measurement of some few observables. They do not require the
complete determination of the quantum state, which is regarded as a main
advantage. On this paper it is experimentally analyzed an entanglement witness
recently proposed in the context of Nuclear Magnetic Resonance (NMR)
experiments to test it in some Bell-diagonal states. We also propose some
optimal entanglement witness for Bell-diagonal states. The efficiency of the
two types of EW's are compared to a measure of entanglement with tomographic
cost, the generalized robustness of entanglement. It is used a GRAPE algorithm
to produce an entangled state which is out of the detection region of the EW
for Bell-diagonal states. Upon relaxation, the results show that there is a
region in which both EW fails, whereas the generalized robustness still shows
entanglement, but with the entanglement witness proposed here with a better
performance
Knot soliton in Weinberg-Salam model
We study numerically the topological knot solution suggested recently in the
Weinberg-Salam model. Applying the SU(2) gauge invariant Abelian projection we
demonstrate that the restricted part of the Weinberg-Salam Lagrangian
containing the interaction of the neutral boson with the Higgs scalar can be
reduced to the Ginzburg-Landau model with the hidden SU(2) symmetry. The energy
of the knot composed from the neutral boson and Higgs field has been evaluated
by using the variational method with a modified Ward ansatz. The obtained
numerical value is 39 Tev which provides the upper bound on the electroweak
knot energy.Comment: 6 pages, 3 figures, analysis of stability adde
Electronic transport and vibrational modes in the smallest molecular bridge: H2 in Pt nanocontacts
We present a state-of-the-art first-principles analysis of electronic
transport in a Pt nanocontact in the presence of H2 which has been recently
reported by Smit et al. in Nature 419, 906 (2002). Our results indicate that at
the last stages of the breaking of the Pt nanocontact two basic forms of bridge
involving H can appear. Our claim is, in contrast to Smit et al.'s, that the
main conductance histogram peak at G approx 2e^2/h is not due to molecular H2,
but to a complex Pt2H2 where the H2 molecule dissociates. A first-principles
vibrational analysis that compares favorably with the experimental one also
supports our claim .Comment: 5 pages, 3 figure
Properties of the Fixed Point Lattice Dirac Operator in the Schwinger Model
We present a numerical study of the properties of the Fixed Point lattice
Dirac operator in the Schwinger model. We verify the theoretical bounds on the
spectrum, the existence of exact zero modes with definite chirality, and the
Index Theorem. We show by explicit computation that it is possible to find an
accurate approximation to the Fixed Point Dirac operator containing only very
local couplings.Comment: 38 pages, LaTeX, 3 figures, uses style [epsfig], a few comments and
relevant references adde
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