3,735 research outputs found
Organic rapeseed production in Finland
Most of the 56 organic rapeseed growers interviewed in this research acknowledged modest success in rapeseed yield (often under 500 kg/ha, on average about 800-900 kg/ha), but kept continuing cultivation because of other benefits such as good price and well functioning markets of the product, flexibility in sowing time, possibility to cultivate a temporary fallow to fight the weeds, and need for protein rich fodder for own or neighbor livestock. The main complications in rapeseed cultivation were unfavorable weather conditions, pests and insufficient nutrient levels for optimal yields. The farmers followed carefully the instructions from research and advisory institutions, but were also innovative in developing their own solutions to problems. Because of different conditions with neighboring farms, different soil types and climatic conditions, different sources of fertilizers and availability of pollinators, tailor-made solutions for every farm individually are imperative. Despite problems most farmers were optimistic and were readily investing in the future e.g. by renting and buying more field area for cultivation. Success in organic rapeseed cultivation seems to coincide with optimism, good relationships with family members and neighbors, availability of affordable fertilizers and relatively large cultivation area for efficient crop rotation
Clover rot (Sclerotinia trifolium) and Fusarium fungi in organic red clover in Finland
Sclerotinia trifolium is economically one of the most important pathogens of red clover in Europe and North America, while many Fusarium species can cause root rot in red clover in certain environmental conditions. During the years 2003-2004 S. trifolium was found only in the Northern and Eastern part of Finland, although in 1960's it was common everywhere in Finland
Molecular coupling of light with plasmonic waveguides
We use molecules to couple light into and out of microscale plasmonic
waveguides. Energy transfer, mediated by surface plasmons, from donor molecules
to acceptor molecules over ten micrometer distances is demonstrated. Also
surface plasmon coupled emission from the donor molecules is observed at
similar distances away from the excitation spot. The lithographic fabrication
method we use for positioning the dye molecules allows scaling to nanometer
dimensions. The use of molecules as couplers between far-field and near-field
light offers the advantages that no special excitation geometry is needed, any
light source can be used to excite plasmons and the excitation can be localized
below the diffraction limit. Moreover, the use of molecules has the potential
for integration with molecular electronics and for the use of molecular
self-assembly in fabrication. Our results constitute a proof-of-principle
demonstration of a plasmonic waveguide where signal in- and outcoupling is done
by molecules.Comment: 9 pages, 5 figure
Control of potato late blight by caraway oil in organic farming
Caraway (Carum carvi) seeds contain biologically active essential oils, which have shown potential in controlling Phytophthora infestans (P.i.). An attempt is being made to develop a P.i. control strategy for organic farming based on caraway oil
UBVRI photopolarimetry of the long period eclipsing AM Herculis binary V1309
We report simultaneous UBVRI photo-polarimetric observations of the long
period (7.98 h) AM Her binary V1309 Ori. The length and shape of the eclipse
ingress and egress varies from night to night. We suggest this is due to the
variation in the brightness of the accretion stream. By comparing the phases of
circular polarization zero-crossovers with previous observations, we confirm
that V1309 Ori is well synchronized, and find an upper limit of 0.002 percent
for the difference between the spin and orbital periods. We model the
polarimetry data using a model consisting of two cyclotron emission regions at
almost diametrically opposite locations, and centered at colatitude 35 (deg)
and 145 (deg) on the surface of the white dwarf. We also present archive X-ray
observations which show that the negatively polarised accretion region is X-ray
bright.Comment: 11 pages, 12 figures (2 colour), Fig1 and Fig 4 are in lower
resolution than in original paper, accepted for publication in Monthly
Notices of the Royal Astronomical Societ
Multi-mode lasing in supercell plasmonic nanoparticle arrays
Multicolour light sources can be used in applications such as lighting and
multiplexing signals. In photonic and plasmonic systems, one way to achieve
multicolour light is via multi-mode lasing. To achieve this, plasmonic
nanoparticle arrays are typically arranged in superlattices that lead to
multiple dispersions of the single arrays coupled via the superlattice Bragg
modes. Here, we show an alternative way to enable multi-mode lasing in
plasmonic nanoparticle arrays. We design a supercell in a square lattice by
leaving part of the lattice sites empty. This results in multiple dispersive
branches caused by the supercell period and hence creates additional band edges
that can support lasing. We experimentally demonstrate multi-mode lasing in
such a supercell array. Furthermore, we identify the lasing modes by
calculating the dispersion by combining the structure factor of the array
design with an empty lattice approximation. We conclude that the lasing modes
are the 74th - and 106th -point of the supercell. By tuning the
square lattice period with respect to the gain emission we can control the
modes that lase. Finally, we show that the lasing modes exhibit a combination
of transverse electric and transverse magnetic mode characteristics in
polarization resolved measurements
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