17,769 research outputs found
Implementation of a 2-D 8x8 IDCT on the Reconfigurable Montium Core
This paper describes the mapping of a two-dimensional inverse discrete cosine transform (2-D IDCT) onto a wordlevel reconfigurable Montium Processor. This shows that the IDCT is mapped onto the Montium tile processor (TP) with reasonable effort and presents performance numbers in terms of energy consumption, speed and silicon costs. The Montium results are compared with the IDCT implementation on three other architectures: TI DSP, ASIC and ARM
Comparison of indices for the prediction of nitrogen mineralization after destruction of managed grassland
Intensively managed grasslands are occasionally chemically killed with herbicide and ploughed in order to grow an arable crop. After this management, large N mineralization rates with large losses to the environment are commonly observed. However, it remains to be determined to what extent the chemical killing contribute to increased N mineralization. In this study the potential nitrogen (N) mineralization from grasslands, that were killed with herbicides but otherwise undisturbed, was investigated in a laboratory experiment with undisturbed soil columns. Subsequently we assessed the predictive value of several laboratory indices for N mineralization after chemically killing of the grass. Mineralization rates varied from 0.5 to 3.0 g N m-2 wk-1. The contents of total N, total C, dissolved organic carbon (DOC) and hot-KCl extractable NH4 + were best related to N mineralization rates (R2=50, 48, 38 and 47%, respectively). In combination with information on the N content of the roots and stubble and the age of grassland at destruction, up to 62% of the variation in N mineralization rates could be explained. Although previous studies suggested that dissolved organic nitrogen (DON) is a good indicator for mineralization rates, this was not the case after chemically killing grass in the current study
A Reconfigurable Platform For Cognitive Radio
Today¿s rigid spectrum allocation scheme creates a spectrum scarcity problem for future wireless communications. Measurements show that a wide range of the allocated frequency bands are rarely used. Cognitive radio is a novel approach to improve the spectrum usage, which is able to sense the spectrum and adapt its transmission while coexisting with the licensed spectrum user. A reconfigurable radio platform is required to provide enough adaptivity for cognitive radio. In this paper, we propose a cognitive radio system architecture and discuss its possible implementation on a heterogeneous reconfigurable radio platform
Chern-Simons number asymmetry from CP-violation during tachyonic preheating
We consider the creation of non-zero Chern-Simons number in a model of the
early Universe, where the Higgs field experiences a fast quench at the end of
inflation. We perform numerical lattice simulations in the Abelian Higgs model
in 1+1 dimensions and in the SU(2)-Higgs model in 3+1 dimensions with an added
effective CP-violating term. We also comment on the appropriate choice of
vacuum initial conditions for classical simulations.Comment: 5 pages, 10 figures, to appear in the proceedings of SEWM2002.
Modified presentation of final result. Results unchange
Sexual hormones in Achyla. V. Properties of hormone A of Achyla bisexualis
1. The hormonal coordinating mechanism of the sexual process in Achlya is briefly reviewed.
2. A technique is described for culturing the female plant of Achlya bisexualis in sufficient quantity to furnish material for the chemical study of hormone A.
3. A modification of the biological assay for hormone A is described.
4. Many of the properties of hormone A have been determined: (a) solubilities in common organic solvents, (b) adsorption, (c) stability, (d) inactivation, and (e) reactions with certain reagents.
5. A procedure is described whereby enormous enrichment of the active principle has been achieved
Lattice Computation of a Magnetic Monopole Mass
A single magnetic monopole in pure SU(2) gauge theory is simulated on the
lattice and its mass is computed in the full quantum theory. The results are
relevant for our proposed realization of the dual superconductor hypothesis of
confinement.Comment: 3 pages PostScript, to appear in the Proceedings of IMACS93 (St.
Louis, USA, Oct. 1993). Registration numbers ITFA-93-38 (Amsterdam),
DFTUZ/93/21 (Zaragoza
W-Particle Distribution in ElectroWeak Tachyonic Pre-Heating
Results are presented of a numerical study of the distribution of W-bosons
generated in a tachyonic electroweak pre-heating transitionComment: Contribution to Strong and ElectroWeak Matter 2002, 5 page
Xanthurenic acid and its rôle in the trytophane metabolism of pyroxidine-deficient rats
In a previous publication (1) the isolation of a green pigment from the urine of pyridoxine-deficient rats was described. The green pigment was shown to be the product of a reaction between ferric ammonium sulfate or other ferric salts and a compound whose nature was unknown. This compound has now been isolated in crystalline form. It is a yellow pigment and has been identified as xanthurenic acid
Heavy cosmic strings
We argue that cosmic strings with high winding numbers generally form in
first-order gauge symmetry breaking phase transitions, and we demonstrate this
using computer simulations. These strings are heavier than single-winding
strings and therefore more easily observable. Their cosmological evolution may
also be very different.Comment: 4 pages, updated to match the published versio
- …