14,813 research outputs found
Quantum properties of the codirectional three-mode Kerr nonlinear coupler
We investigate the quantum properties for the codirectional three-mode Kerr
nonlinear coupler. We investigate single-, two- and three-mode quadrature
squeezing, Wigner function and purity. We prove that this device can provide
richer nonclassical effects than those produced by the conventional coupler,
i.e. the two-mode Kerr coupler. We show that it can provide squeezing and the
quadrature squeezing exhibiting leaf-revival-collapse phenomenon in dependence
on the values of the interaction parameters. In contrast to the conventional
Kerr coupler two different forms of cat states can be simultaneously generated
in the waveguides. We deduce conditions required for the complete
disentanglement between the components of the system.Comment: 23 pages, 6 figure
Organic farm conventionalisation and farmer practices in China, Brazil and Egypt.
Certified organic agriculture stipulates a range of principles and standards, which govern farmer practices. The recent global expansion of organic agriculture has raised new challenges for organic agriculture, particularly whether management practices in organic farms are subject to the forces of conventionalisation. We studied changes in agroecological practices in certified organic farms in China, Brazil and Egypt. The study takes departure in the conventionalisation hypothesis and the analysis is framed using organic and agroecological principles. The study focuses on agroecological design principles, inherent to organic agriculture, of diversity in crop production, pest, disease and weed management, and soil fertility management. The research design was as a multiple case study of five cases in China, Brazil and Egypt. We show that the adoption of organic agriculture has induced fundamental changes in organic farmer management practices, although agroecological practices of organic farmers do not fulfil organic principles. The forces of conventionalisation exert a strong influence on changes in organic farmer practices. Organic ‘niche’ market crops with a high-value influence organic farmers’ management decisions, particularly regarding the prioritisation of diversity in the cropping systems for agroecological purposes. The farming systems have therefore not undergone major changes of their cropping patterns. Furthermore, there was a general heavy reliance upon input substitution for pest and soil fertility management. This study thus presents new data and a novel analysis of the implications at the farm scale of the global expansion of organic agriculture, and the influence of conventionalisation on farmers practices
Higher-order squeezing for the codirectional Kerr nonlinear coupler
In this Letter we study the evolution of the higher-order squeezing, namely,
th-order single-mode squeezing, sum- and difference-squeezing for the
codirectional Kerr nonlinear coupler. We show that the amount of squeezing
decreases when , i.e. the squeezing order, increases. For specific values of
the interaction parameters squeezing factors exhibit a series of
revival-collapse phenomena, which become more pronounced when the value of
increases. Sum-squeezing can provide amounts of squeezing greater than those
produced by the th higher-order () squeezing for the same values of
interaction parameters and can map onto amplitude-squared squeezing. Further,
we prove that the difference-squeezing is not relevant measure for obtaining
information about squeezing from this device.Comment: 13 pages, 3 figure
Reduced survival of total knee arthroplasty after previous unicompartmental knee arthroplasty compared with previous high tibial osteotomy:a propensity-score weighted mid-term cohort study based on 2,133 observations from the Danish Knee Arthroplasty Registry
Prior High Tibial Osteotomy Does Not Affect the Survival of Total Knee Arthroplasties:Results From the Danish Knee Arthroplasty Registry
High completeness and accurate reporting of key variables make data from the Danish shoulder arthroplasty registry a valuable source of information
Fatal cardiac arrhythmia caused by tumor lysis in a patient with diffuse large B-cell lymphoma upon start of R-CHOP
Market Integration Shape Organic Farmers’ Organisation
Increasing consumption of organic products in globalised food chains will require the involvement of thousands more smallholder farmers in many regions of the world. A study of Egypt, China and Uganda identified the three key factors of property rights regimes, cultural differences and social organisation as determents of the supply chain organization and farmers’ degree of direct integration in the export markets. Patterns are emerging where smallholder farmers are being socially and economically linked to larger farmers who may do some processing before the raw materials are handed over to the contracting company. Where transactions costs are high, local communities may develop and contract out the land directly to exporting companies who farm using employees. Four organisational patterns are identified which each leads to different types of livelihood benefits for the producers; preliminary results indicate that income and a reliable market access is the dominant benefits
Percolation in deposits for competitive models in (1+1)-dimensions
The percolation behaviour during the deposit formation, when the spanning
cluster was formed in the substrate plane, was studied. Two competitive or
mixed models of surface layer formation were considered in (1+1)-dimensional
geometry. These models are based on the combination of ballistic deposition
(BD) and random deposition (RD) models or BD and Family deposition (FD) models.
Numerically we find, that for pure RD, FD or BD models the mean height of the
percolation deposit grows with the substrate length according to
the generalized logarithmic law , where
(RD), (FD) and (BD).
For BD model, the scaling law between deposit density and its mean height
at the point of percolation of type are observed, where is a scaling
coefficient. For competitive models the crossover, %in versus
corresponding to the RD or FD -like behaviour at small and the BD-like
behaviour at large are observed.Comment: 8 pages,4 figures, Latex, uses iopart.cl
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