Search results for "Reduction"
showing 10 items of 2058 documents
Molecular analysis of the nitrate-reducing community from unplanted and maize-planted soils
2002
ABSTRACT Microorganisms that use nitrate as an alternative terminal electron acceptor play an important role in the global nitrogen cycle. The diversity of the nitrate-reducing community in soil and the influence of the maize roots on the structure of this community were studied. The narG gene encoding the membrane bound nitrate reductase was selected as a functional marker for the nitrate-reducing community. The use of narG is of special interest because the phylogeny of the narG gene closely reflects the 16S ribosomal DNA phylogeny. Therefore, targeting the narG gene provided for the first time a unique insight into the taxonomic composition of the nitrate-reducing community in planted an…
Electroorganic synthesis of nitriles via a halogen-free domino oxidation–reduction sequence
2015
A direct electroorganic sequence yielding nitriles from oximes in undivided cells is reported. Despite the fact that intermediate nitrile oxides might be formed, the method is viable to prepare benzonitriles without substituents ortho to the aldoxime moiety. This constant current method is easy to perform for a broad scope of substrates and employs common electrodes, such as graphite and lead.
Possible nitrogen fertilization of the early Earth Ocean by microbial continental ecosystems
2018
While significant efforts have been invested in reconstructing the early evolution of the Earth’s atmosphere–ocean–biosphere biogeochemical nitrogen cycle, the potential role of an early continental contribution by a terrestrial, microbial phototrophic biosphere has been largely overlooked. By transposing to the Archean nitrogen fluxes of modern topsoil communities known as biological soil crusts (terrestrial analogs of microbial mats), whose ancestors might have existed as far back as 3.2 Ga ago, we show that they could have impacted the evolution of the nitrogen cycle early on. We calculate that the net output of inorganic nitrogen reaching the Precambrian hydrogeological system could hav…
Comparative Genomics of Blattabacterium cuenoti: The Frozen Legacy of an Ancient Endosymbiont Genome
2013
Many insect species have established long-term symbiotic relationships with intracellular bacteria. Symbiosis with bacteria has provided insects with novel ecological capabilities, which have allowed them colonize previously unexplored niches. Despite its importance to the understanding of the emergence of biological complexity, the evolution of symbiotic relationships remains hitherto a mystery in evolutionary biology. In this study, we contribute to the investigation of the evolutionary leaps enabled by mutualistic symbioses by sequencing the genome of Blattabacterium cuenoti, primary endosymbiont of the omnivorous cockroach Blatta orientalis, and one of the most ancient symbiotic associa…
Moisture absorption, thermal conductivity and noise mitigation of clay based plasters: The influence of mineralogical and textural characteristics
2016
Abstract Three pre-mixed clay based plasters successfully employed in green building practices in several European countries (Spain, France, Germany, and United Kingdom), mainly used for interior wall coating and finishing, were tested in this paper. Their compositional and textural characteristics as well as plastic behaviour were investigated through a multi-analytical approach in a previous paper. A natural earth (Terra Rossa red soil sampled in north-western Sicily), theoretically appropriate for the production of earthen plaster, was also subjected to the same analytical routine and compared with the three commercially available products. Humidity control capacity by the determination …
Signal-to-noise ratio in reproducing kernel Hilbert spaces
2018
This paper introduces the kernel signal-to-noise ratio (kSNR) for different machine learning and signal processing applications}. The kSNR seeks to maximize the signal variance while minimizing the estimated noise variance explicitly in a reproducing kernel Hilbert space (rkHs). The kSNR gives rise to considering complex signal-to-noise relations beyond additive noise models, and can be seen as a useful signal-to-noise regularizer for feature extraction and dimensionality reduction. We show that the kSNR generalizes kernel PCA (and other spectral dimensionality reduction methods), least squares SVM, and kernel ridge regression to deal with cases where signal and noise cannot be assumed inde…
Impulse noise removal on an embedded, low memory SIMD processor
2003
Vector median filters efficiently reduce noise while preserving image details. However, their high computational complexity for color images makes them impractical for real-time systems. We propose new computationally efficient filtering algorithms, called index mapping filters (IMF). These filtering algorithms are accelerated by implementing them on a massively data parallel processor array. In addition to greater computational efficiency, these algorithms result in robust noise reduction of corrupted color images. Analyses of mean square error, signal-to-noise-ratio, and visual comparison metrics indicate that IMF are competitive with the vector median filter (VMF) in their ability to cor…
Signal Denoising with Harten’s Multiresolution Using Interpolation and Least Squares Fitting
2014
Harten’s multiresolution has been successfully applied to the signal compression using interpolatory reconstructions with nonlinear techniques. Here we study the applicability of these techniques to remove noise to piecewise smooth signals. We use two reconstruction types: interpolatory and least squares, and we introduce ENO and SR nonlinear techniques. The standard methods adaptation to noisy signals and the comparative of the different schemes are the subject of this paper.
Genome Evolution in the Primary Endosymbiont of Whiteflies Sheds Light on Their Divergence
2015
International audience; Hemipteran insects are well-known in their ability to establish symbiotic relationships with bacteria. Among them, heteropteran insects present an array of symbiotic systems, ranging from the most common gut crypt symbiosis to the more restricted bacteriome-associated endosymbiosis, which have only been detected in members of the superfamily Lygaeoidea and the family Cimicidae so far. Genomic data of heteropteran endosymbionts are scarce and have merely been analyzed from the Wolbachia endosymbiont in bed bug and a few gut crypt-associated symbionts in pentatomoid bugs. In this study, we present the first detailed genomic analysis of a bacteriome-associated endosymbi…
A Comparison of Special Bonding Techniques for Transmission and Distribution Cables under Normal and Fault Conditions
2021
In this article, a review of the existing special bonding techniques for medium voltage and high-voltage cables is presented. Special bonding techniques have the purpose of reducing sheath currents, thereby limiting copper losses and the reduction of the ampacity of cables. The literature review shows various bonding techniques and how these have evolved over the years thanks to new technologies. Simulations of each technique are performed in MATLAB/Simulink, to compare their strengths and drawbacks both under normal conditions and in the presence of a single-line-to-ground fault.