21,940 research outputs found
Combined production of broilers and fruits
Combined production of broilers and fruit trees is a subject often discussed in organic fruit
production in Denmark. Very little research has been carried out on this type of production
system. In organic production in Denmark, nearly no pesticides are allowed, so the need
for alternative pest control is large. Apple sawfly (Hoplocampa testudinea) and pear midge
(Contarinia pyrivora) cause big crop losses in apples and pears respectively, in unsprayed
organic fruit production. Both insects infest fruitlets and cause these to drop prematurely
after which the pests pupate in the topsoil. In the present experiment a research orchard
with the varieties ‘Discovery’ and ‘Conference’ were used as outdoor area for broilers to
minimise the population of sawflies and pear midges, and to reduce the need for weeding
and manuring. The trees were kept unsprayed. Fruit yield and fruit quality were assessed
at harvest. White sticky traps were placed in the test area in order to measure the
occurrence of sawfly over time. The infestation of pear midge was investigated counting
the infested fruitlets in clusters on trees at the centre of the plots. The catch of apple
sawflies was reduced in the combined apple and broiler production, but no significant
effect on the yield or the fruit quality was seen. Experiences from on-farm research show
that combining fruit and egg-production is one way to reduce the problem with apple
sawfly, but poultry alone is not a sufficient way of controlling sawflies. The welfare and
health of the broilers were excellent under fruit trees
Error correction in ensemble registers for quantum repeaters and quantum computers
We propose to use a collective excitation blockade mechanism to identify
errors that occur due to disturbances of single atoms in ensemble quantum
registers where qubits are stored in the collective population of different
internal atomic states. A simple error correction procedure and a simple
decoherence-free encoding of ensemble qubits in the hyperfine states of alkali
atoms are presented.Comment: 4 pages, 2 figure
Universal Quantum Computation in a Neutral Atom Decoherence Free Subspace
In this paper, we propose a way to achieve protected universal computation in
a neutral atom quantum computer subject to collective dephasing. Our proposal
relies on the existence of a Decoherence Free Subspace (DFS), resulting from
symmetry properties of the errors. After briefly describing the physical system
and the error model considered, we show how to encode information into the DFS
and build a complete set of safe universal gates. Finally, we provide numerical
simulations for the fidelity of the different gates in the presence of
time-dependent phase errors and discuss their performance and practical
feasibility.Comment: 7 pages, 8 figure
Conditional expectations associated with quantum states
An extension of the conditional expectations (those under a given subalgebra
of events and not the simple ones under a single event) from the classical to
the quantum case is presented. In the classical case, the conditional
expectations always exist; in the quantum case, however, they exist only if a
certain weak compatibility criterion is satisfied. This compatibility criterion
was introduced among others in a recent paper by the author. Then,
state-independent conditional expectations and quantum Markov processes are
studied. A classical Markov process is a probability measure, together with a
system of random variables, satisfying the Markov property and can equivalently
be described by a system of Markovian kernels (often forming a semigroup). This
equivalence is partly extended to quantum probabilities. It is shown that a
dynamical (semi)group can be derived from a given system of quantum observables
satisfying the Markov property, and the group generators are studied. The
results are presented in the framework of Jordan operator algebras, and a very
general type of observables (including the usual real-valued observables or
self-adjoint operators) is considered.Comment: 10 pages, the original publication is available at http://www.aip.or
The nucleoside analog GS-441524 strongly inhibits feline infectious peritonitis (FIP) virus in tissue culture and experimental cat infection studies.
Feline infectious peritonitis (FIP) is a common and highly lethal coronavirus disease of domestic cats. Recent studies of diseases caused by several RNA viruses in people and other species indicate that antiviral therapy may be effective against FIP in cats. The small molecule nucleoside analog GS-441524 is a molecular precursor to a pharmacologically active nucleoside triphosphate molecule. These analogs act as an alternative substrate and RNA-chain terminator of viral RNA dependent RNA polymerase. We determined that GS-441524 was non-toxic in feline cells at concentrations as high as 100 uM and effectively inhibited FIPV replication in cultured CRFK cells and in naturally infected feline peritoneal macrophages at concentrations as low as 1 uM. We determined the pharmacokinetics of GS-441524 in cats in vivo and established a dosage that would sustain effective blood levels for 24 h. In an experimental FIPV infection of cats, GS-441524 treatment caused a rapid reversal of disease signs and return to normality with as little as two weeks of treatment in 10/10 cats and with no apparent toxicity
Bose Einstein condensation on inhomogeneous amenable graphs
We investigate the Bose-Einstein Condensation on nonhomogeneous amenable
networks for the model describing arrays of Josephson junctions. The resulting
topological model, whose Hamiltonian is the pure hopping one given by the
opposite of the adjacency operator, has also a mathematical interest in itself.
We show that for the nonhomogeneous networks like the comb graphs, particles
condensate in momentum and configuration space as well. In this case different
properties of the network, of geometric and probabilistic nature, such as the
volume growth, the shape of the ground state, and the transience, all play a
role in the condensation phenomena. The situation is quite different for
homogeneous networks where just one of these parameters, e.g. the volume
growth, is enough to determine the appearance of the condensation.Comment: 43 pages, 12 figures, final versio
Inducing spin-dependent tunneling to probe magnetic correlations in optical lattices
We suggest a simple experimental method for probing antiferromagnetic spin
correlations of two-component Fermi gases in optical lattices. The method
relies on a spin selective Raman transition to excite atoms of one spin species
to their first excited vibrational mode where the tunneling is large. The
resulting difference in the tunneling dynamics of the two spin species can then
be exploited, to reveal the spin correlations by measuring the number of doubly
occupied lattice sites at a later time. We perform quantum Monte Carlo
simulations of the spin system and solve the optical lattice dynamics
numerically to show how the timed probe can be used to identify
antiferromagnetic spin correlations in optical lattices.Comment: 5 pages, 5 figure
Field efficacy of new compounds to replace copper for scab control in organic apple production
Efficacy of compounds was investigated in field experiments in Denmark and the Netherlands according to EPPO guidelines. Some Yucca extracts and potassium bicarbonate had an efficacy similar to sulphur on leaves. Addition of sulphur to Yucca 1 and to potassium bicarbonate increased the level of efficacy to that of copper. This confirms results from earlier years. Although a dose increase resulted in better efficacy, this was more prominent for Yucca1 than for potassium bicarbonate
The productivity and financial impacts of eight types of environmental enrichment for broiler chickens
Reduced mobility in broilers can contribute to leg health problems. Environmental enrichment has been suggested as one approach to combat this through stimulating increased physical activity. Past studies have tested the effect of environmental enrichments on bird behaviour, health and welfare, but few have estimated their financial impacts. This study tested the impact of eight types of environmental enrichment on enterprise net margin, accounting for direct intervention costs plus indirect effects via changes to bird mortality, weight, feed intake, feed conversion ratio, and foot pad dermatitis. The trial used 58 pens each containing approximately 500 broilers (Ross 308) at a stocking density of 40 kg/m2. The environmental enrichments were: roughage, vertical panels, straw bales, elevated platforms (5 and 30 cm), increased distances between feed and water (7 and 3.5 m) and stocking density reduced to 34 kg/m2, plus a control group. Mortality was recorded daily and feed intake and weight weekly. Footpad dermatitis was assessed on day 35. Only one intervention improved financial performance (3.5 m between feed and water) above the control, suggesting that most environmental enrichment would have a negative financial impact due to the additional intervention costs, unless consumers were willing to pay a price premium
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