178 research outputs found
Ashes for organic farming
Nowadays only eight percent of the cultivated field area is used for organic farming. The Ministry of Agriculture and Forestry has published the guidelines for the program of organic farming to diversify the supply and the consumption of organic food. The aim is to increase organically arable land to 20% by the year 2020.The demand of organic fertilizer products is strongly increasing. Interest in forestry by-products (ash, bark, zero fiber, etc.) for use in organic production has recently been exceptionally high. For example, development of pelleted fertilizers with zero fiber, ash and a nitrogen-containing fertilizer material is in progress.The ash fertilizer contains many valuable nutrients in fairly optimal ratios: these include phosphorus, potassium, manganese, magnesium, sulfur, zinc, calcium, boron, cobalt, copper and smaller amounts of other trace elements. Ashes contain phosphorus in large amounts, which is useful in organic production. More important nutrients than phosphorus and potassium are apparently trace elements. Neutralizing value of the ash is quite rapid comparedto many liming materials allowed in organic farming. The price quality ratio of ash as a liming material is also good.The use of clean wood ash is permissible in organic production. Peat and straw ash cannot be used in organic production because of the fact that in the EU peat is not considered a renewable resource. Restrictions include only inputs from outside of the organic farm
Orbital Competition in Bilayer Graphene's Fractional Quantum Hall Effect
The lowest Landau level of bilayer graphene has an octet of internal degrees
of freedom, composed from spin, valley and orbital two-level systems. Dominance
of orbitals over orbitals in low energy quantum fluctuations leads
to distinct fractional quantum Hall characteristics compared dominance of
over . The competition between and orbitals depends
sensitively on particle-hole asymmetry and on Lamb shifts due to exchange
interactions with the negative energy sea, which must be accounted for
simultaneously in assessing the orbital competition. We identify the
circumstances under which , which supports strong even-denominator FQH
states with non-abelian quasiparticles, emerges robustly as the low-energy
Landau level
Bit error rate performance of a generalized diversity selectioncombining scheme in Nakagami fading channels
The severity of fading on mobile communication channels calls for the combining of multiple diversity sources to achieve acceptable error rate performance. Traditional approaches perform the combining of the different diversity sources using either: the conventional selective diversity combining (CSC), equal-gain combining (EGC), or maximal-ratio combining (MRC) schemes. CSC and MRC are the two extremes of compromise between performance quality and complexity. This paper presents a generalized diversity selection combining (GSC) scheme in which only those diversity branches whose energy levels are above a specified threshold are combined. Doing so, the proposed scheme will have a bit error (BER) performance that is upper- and lower-bounded by those of the CSC and MRC schemes respectively. Simulation results for the performances of this scheme over Nakagami (1960) fading channels are show
An adaptive error control system using hybrid ARQ schemes
A simple and efficient system utilizing the class of Hamming codes in a cascaded manner is proposed to provide high throughput over a wide range of channel bit error probability. Comparisons with other adaptive schemes indicate that the proposed system is superior from the point of view of throughput, while still providing the same order of reliability as an ARQ (automatic repeat request) system. The main feature of this system is that the receiver uses the same decoder for decoding the received information after each transmission while the error-correcting capability of the code increases. As a result, the system is kept to the minimum complexity and the system performance is improve
An adaptive error control system using hybrid ARQ schemes
A simple and efficient system utilizing the class of Hamming codes in a cascaded manner is proposed to provide high throughput over a wide range of channel bit error probability. Comparisons with other adaptive schemes indicate that the proposed system is superior from the point of view of throughput, while still providing the same order of reliability as an ARQ (automatic repeat request) system. The main feature of this system is that the receiver uses the same decoder for decoding the received information after each transmission while the error-correcting capability of the code increases. As a result, the system is kept to the minimum complexity and the system performance is improve
Bit error rate performance of a generalized diversity selectioncombining scheme in Nakagami fading channels
The severity of fading on mobile communication channels calls for the combining of multiple diversity sources to achieve acceptable error rate performance. Traditional approaches perform the combining of the different diversity sources using either: the conventional selective diversity combining (CSC), equal-gain combining (EGC), or maximal-ratio combining (MRC) schemes. CSC and MRC are the two extremes of compromise between performance quality and complexity. This paper presents a generalized diversity selection combining (GSC) scheme in which only those diversity branches whose energy levels are above a specified threshold are combined. Doing so, the proposed scheme will have a bit error (BER) performance that is upper- and lower-bounded by those of the CSC and MRC schemes respectively. Simulation results for the performances of this scheme over Nakagami (1960) fading channels are show
Reliability-throughput: optimisation for adaptive forward errorcorrection systems
Adaptive error control systems are very efficient for digital transmission over time-varying channels. An adaptive forward error correction system based on code selection is considered. An estimation of the channel quality is utilised by the transmitter to adaptively encode the information bits to be sent over the channel. The proper code is selected to optimise the system performance in terms of the two most important evaluation measures: throughput and reliability. The optimisation technique is applied to the case of an adaptive system using BCH codes over Rayleigh fading channels. The achievement of the adaptive system over the non-adaptive system is studied in detai
Reliability-throughput: optimisation for adaptive forward errorcorrection systems
Adaptive error control systems are very efficient for digital transmission over time-varying channels. An adaptive forward error correction system based on code selection is considered. An estimation of the channel quality is utilised by the transmitter to adaptively encode the information bits to be sent over the channel. The proper code is selected to optimise the system performance in terms of the two most important evaluation measures: throughput and reliability. The optimisation technique is applied to the case of an adaptive system using BCH codes over Rayleigh fading channels. The achievement of the adaptive system over the non-adaptive system is studied in detai
Laser-based angle-resolved photoemission spectroscopy with micrometer spatial resolution and detection of three-dimensional spin vector
We have developed a state-of-the-art apparatus for laser-based spin- and
angle-resolved photoemission spectroscopy with micrometer spatial resolution
(micro-SARPES). This equipment is achieved through the combination of a
high-resolution photoelectron spectrometer, a 6-eV laser with high photon flux
that is focused down to a few micrometers, a high-precision sample stage
control system, and a double very-low-energy-electron-diffraction spin
detector. The setup achieves an energy resolution of 1.5 (5.5) meV without
(with) the spin detection mode, compatible with a spatial resolution better
than 10 micrometers. This enables us to probe both spatially-resolved
electronic structures and vector information of spin polarization in three
dimensions. The performance of micro-SARPES apparatus is demonstrated by
presenting ARPES and SARPES results from topological insulators and Au
photolithography patterns on a Si (001) substrate.Comment: 18 pages, 5 figure
Resorbable screws versus pins for optimal transplant fixation (SPOT) in anterior cruciate ligament replacement with autologous hamstring grafts: rationale and design of a randomized, controlled, patient and investigator blinded trial [ISRCTN17384369]
BACKGROUND: Ruptures of the anterior cruciate ligament (ACL) are common injuries to the knee joint. Arthroscopic ACL replacement by autologous tendon grafts has established itself as a standard of care. Data from both experimental and observational studies suggest that surgical reconstruction does not fully restore knee stability. Persisting anterior laxity may lead to recurrent episodes of giving-way and cartilage damage. This might at least in part depend on the method of graft fixation in the bony tunnels. Whereas resorbable screws are easy to handle, pins may better preserve graft tension. The objective of this study is to determine whether pinning of ACL grafts reduces residual anterior laxity six months after surgery as compared to screw fixation. DESIGN/ METHODS: SPOT is a randomised, controlled, patient and investigator blinded trial conducted at a single academic institution. Eligible patients are scheduled to arthroscopic ACL repair with triple-stranded hamstring grafts, conducted by a single, experienced surgeon. Intraoperatively, subjects willing to engage in this study will be randomised to transplant tethering with either resorbable screws or resorbable pins. No other changes apply to locally established treatment protocols. Patients and clinical investigators will remain blinded to the assigned fixation method until the six-month follow-up examination. The primary outcome is the side-to-side (repaired to healthy knee) difference in anterior translation as measured by the KT-1000 arthrometer at a defined load (89 N) six months after surgery. A sample size of 54 patients will yield a power of 80% to detect a difference of 1.0 mm ± standard deviation 1.2 mm at a two-sided alpha of 5% with a t-test for independent samples. Secondary outcomes (generic and disease-specific measures of quality of life, magnetic resonance imaging morphology of transplants and devices) will be handled in an exploratory fashion. CONCLUSION: SPOT aims at showing a reduction in anterior knee laxity after fixing ACL grafts by pins compared to screws
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