7,938 research outputs found
Estimating Parasitism of Colorado Potato Beetle Eggs, \u3ci\u3eLeptinotarsa Decemlineata\u3c/i\u3e (Coleoptera: Chrysomelidae), by \u3ci\u3eEdovum Puttleri\u3c/i\u3e (Hymenoptera: Eulophidae)
A computer simulation was used to evaluate methods for estimating parasitism of Colorado potato beetle egg mass populations by Edovum puttleri. The algorithm incorporated the specific attack behavior of E. puttleri, and a development time for parasitized egg masses of ca. 2.9 times that of healthy egg masses. Of the methods compared, a modification of Southwood\u27s graphical technique was found to be most accurate in relation to the true parasitism derived from the algorithm. A regression equation is presented to correct the error in this method at high levels of parasitism. A second simulation was used to test the accuracy of this correcter where in a jacknife procedure was used to generate a mean and variance for estimates of parasitism
Many-body quantum dynamics of polarisation squeezing in optical fibre
We report new experiments that test quantum dynamical predictions of
polarization squeezing for ultrashort photonic pulses in a birefringent fibre,
including all relevant dissipative effects. This exponentially complex
many-body problem is solved by means of a stochastic phase-space method. The
squeezing is calculated and compared to experimental data, resulting in
excellent quantitative agreement. From the simulations, we identify the
physical limits to quantum noise reduction in optical fibres. The research
represents a significant experimental test of first-principles time-domain
quantum dynamics in a one-dimensional interacting Bose gas coupled to
dissipative reservoirs.Comment: 4 pages, 4 figure
A new dawn? The Roman Catholic Church and environmental issues
This is a PDF version of an article published in New Blackfriars© 1997. The definitive version is available at www.blackwell-synergy.com.This article discusses the stance of the Roman Catholic Church on environmental issues and argues that the Church tends to stay on the fringe rather than get involved. Some of the ways in which Roman Catholic theologians have incorporated environmental issues into theological reflection is discussed, as are environmental challenges facing the Church in Britain (conservation, resources, biodiversity, animal welfare, biotechnology, cooperate/individual ethics, environmental justice, economics/policy development, and global issues)
Decoherence of Quantum-Enhanced Timing Accuracy
Quantum enhancement of optical pulse timing accuracy is investigated in the
Heisenberg picture. Effects of optical loss, group-velocity dispersion, and
Kerr nonlinearity on the position and momentum of an optical pulse are studied
via Heisenberg equations of motion. Using the developed formalism, the impact
of decoherence by optical loss on the use of adiabatic soliton control for
beating the timing standard quantum limit [Tsang, Phys. Rev. Lett. 97, 023902
(2006)] is analyzed theoretically and numerically. The analysis shows that an
appreciable enhancement can be achieved using current technology, despite an
increase in timing jitter mainly due to the Gordon-Haus effect. The decoherence
effect of optical loss on the transmission of quantum-enhanced timing
information is also studied, in order to identify situations in which the
enhancement is able to survive.Comment: 12 pages, 4 figures, submitte
On All-loop Integrands of Scattering Amplitudes in Planar N=4 SYM
We study the relationship between the momentum twistor MHV vertex expansion
of planar amplitudes in N=4 super-Yang-Mills and the all-loop generalization of
the BCFW recursion relations. We demonstrate explicitly in several examples
that the MHV vertex expressions for tree-level amplitudes and loop integrands
satisfy the recursion relations. Furthermore, we introduce a rewriting of the
MHV expansion in terms of sums over non-crossing partitions and show that this
cyclically invariant formula satisfies the recursion relations for all numbers
of legs and all loop orders.Comment: 34 pages, 17 figures; v2: Minor improvements to exposition and
discussion, updated references, typos fixe
Einstein-Podolsky-Rosen correlations via dissociation of a molecular Bose-Einstein condensate
Recent experimental measurements of atomic intensity correlations through
atom shot noise suggest that atomic quadrature phase correlations may soon be
measured with a similar precision. We propose a test of local realism with
mesoscopic numbers of massive particles based on such measurements. Using
dissociation of a Bose-Einstein condensate of diatomic molecules into bosonic
atoms, we demonstrate that strongly entangled atomic beams may be produced
which possess Einstein-Podolsky-Rosen (EPR) correlations in field quadratures,
in direct analogy to the position and momentum correlations originally
considered by EPR.Comment: Final published version (corrections in Ref. [32], updated
references
Outcoupling from a Bose-Einstein condensate with squeezed light to produce entangled atom laser beams
We examine the properties of an atom laser produced by outcoupling from a
Bose-Einstein condensate with squeezed light. We model the multimode dynamics
of the output field and show that a significant amount of squeezing can be
transfered from an optical mode to a propagating atom laser beam. We use this
to demonstrate that two-mode squeezing can be used to produce twin atom laser
beams with continuous variable entanglement in amplitude and phase.Comment: 11 pages, 14 figure
The Yangian origin of the Grassmannian integral
In this paper we analyse formulas which reproduce different contributions to
scattering amplitudes in N=4 super Yang-Mills theory through a Grassmannian
integral. Recently their Yangian invariance has been proved directly by using
the explicit expression of the Yangian level-one generators. The specific
cyclic structure of the form integrated over the Grassmannian enters in a
crucial way in demonstrating the symmetry. Here we show that the Yangian
symmetry fixes this structure uniquely.Comment: 26 pages. v2: typos corrected, published versio
Crystallization and characterization of Y2O3-SiO2 glasses
Glasses in the yttria-silica system with 20 to 40 mol pct Y2O3 were subjected to recrystallization studies after melting at 1900 to 2100 C in W crucibles in 1 and 50 atm N2. The TEM and XRD results obtained indicate the presence of the delta, gamma, gamma prime, and beta-Y2Si2O7 crystalline phases, depending on melting and quenching conditions. Heat treatment in air at 1100 to 1600 C increased the amount of crystallization, and led to the formation of Y2SiO5, cristabalite, and polymorphs of Y2Si2O7. Also investigated were the effects of 5 and 10 wt pct zirconia additions
Cutting Edge : Failure of Antigen-Specific CD4+ T Cell Recruitment to the Kidney during Systemic Candidiasis
Copyright © 2014 The Authors. Acknowledgments We thank E. Bolton and H. Bagavant for reagents and advice. We also acknowledge the staff of the Medical Research Facility at the University of Aberdeen for care of the animals used in this study. This work was supported by the Medical Research Council and the Wellcome Trust.Peer reviewedPublisher PD
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