2,975 research outputs found
PDA-BCJR algorithm for factorial hidden Markov models with application to MIMO equalisation
Publication in the conference proceedings of EUSIPCO, Florence, Italy, 200
Depth-first and breadth-first search based multilevel SGA algorithms for near optimal symbol detection in MIMO systems
Identifying Climate-smart agriculture research needs
Climate-smart agriculture (CSA) is an approach to help agricultural systems worldwide, concurrently addressing three challenge areas: increased adaptation to climate change, mitigation of climate change, and ensuring global food securityâââthrough innovative policies, practices, and financing. It involves a set of objectives and multiple transformative transitions for which there are newly identified knowledge gaps. We address these questions raised by CSA within three areas: conceptualization, implementation, and implications for policy and decision-makers. We also draw up scenarios on the future of the CSA concept in relation to the 4âperâ1000 Initiative (Soils for Food Security and Climate) launched at UNFCCC 21st Conference of the Parties (COP 21). Our analysis shows that there is still a need for further interdisciplinary research on the theoretical foundation of the CSA concept and on the necessary transformations of agriculture and land use systems. Contrasting views about implementation indicate that CSA focus on the âtriple winâ (adaptation, mitigation, food security) needs to be assessed in terms of science-based practices. CSA policy tools need to incorporate an integrated set of measures supported by reliable metrics. Environmental and social safeguards are necessary to make sure that CSA initiatives conform to the principles of sustainability, both at the agriculture and food system levels
Influence of oxide films on primary water stress corrosion cracking initiation of alloy 600
In the present study alloy 600 was tested in simulated pressurised water reactor (PWR) primary water, at 360 °C, under an hydrogen partial pressure of 30 kPa. These testing conditions correspond to the maximum sensitivity of alloy 600 to crack initiation. The resulting oxidised structures (corrosion scale and underlying metal) were characterised. A chromium rich oxide layer was revealed, the underlying metal being chromium depleted. In addition, analysis of the chemical composition of the metal close to the oxide scale had allowed to detect oxygen under the oxide scale and particularly in a triple grain boundary. Implication of such a finding on the crack initiation of alloy 600 is discussed. Significant diminution of the crack initiation time was observed for sample oxidised before stress corrosion tests. In view of these results, a mechanism for stress corrosion crack initiation of alloy 600 in PWR primary water was proposed
Modeling biomass flows at the farm level: a discussion support tool for farmers.
Many simulation models that are used to assess the impact of mixed farming systems have a high level of complexity that is not suitable for teaching farmers about the impacts of their practices.DOI: 10.1051/agro/2009047
Size effect on magnetism of Fe thin films in Fe/Ir superlattices
In ferromagnetic thin films, the Curie temperature variation with the
thickness is always considered as continuous when the thickness is varied from
to atomic planes. We show that it is not the case for Fe in Fe/Ir
superlattices. For an integer number of atomic planes, a unique magnetic
transition is observed by susceptibility measurements, whereas two magnetic
transitions are observed for fractional numbers of planes. This behavior is
attributed to successive transitions of areas with and atomic planes,
for which the 's are not the same. Indeed, the magnetic correlation length
is presumably shorter than the average size of the terraces. Monte carlo
simulations are performed to support this explanation.Comment: LaTeX file with Revtex, 5 pages, 5 eps figures, to appear in Phys.
Rev. Let
An oxygen isotope record of lacustrine opal from a European Maar indicates climatic stability during the Last Interglacial
The penultimate temperate period, 127â110 ka before present (BP), bracketed by abrupt shifts of the global climate system initiating and terminating it, is considered as an analogue of the Holocene because of a similar low global iceâvolume. Ice core records as well as continental and marine records exhibit conflicting evidence concerning the climate variability within this period, the Last Interglacial. We present, for the first time, a highâresolution record of oxygen isotopes in diatom opal of the Last Interglacial obtained from the Ribains Maar in France (44°50âČ09âłN 3°49âČ16âłE). Our results indicate that the Last Interglacial in southwestern Europe was generally a period of climatic stability. The record shows that the temperate period was initiated by an abrupt warm event followed midway by a minor climatic transition to a colder climate. An abrupt isotopic depletion that occurs simultaneously with abrupt changes in pollen and diatom assemblages marks the end of the temperate period, and is correlative with the Melisey I stadial. Variations in the isotopic composition of lakeâwater related to the isotopic composition of precipitation and evaporation dominate the biogenic opal oxygen isotope record
- âŠ