Recovering Arrhythmic EEG Transients from Their Stochastic Interference

Traditionally, the neuronal dynamics underlying electroencephalograms (EEG) have been understood as arising from \textit{rhythmic oscillators with varying degrees of synchronization}. This dominant metaphor employs frequency domain EEG analysis to identify the most prominent populations of neuronal current sources in terms of their frequency and spectral power. However, emerging perspectives on EEG highlight its arrhythmic nature, which is primarily inferred from broadband EEG properties like the ubiquitous $1/f$ spectrum. In the present study, we use an \textit{arrhythmic superposition of pulses} as a metaphor to explain the origin of EEG. This conceptualization has a fundamental problem because the interference produced by the superpositions of pulses generates colored Gaussian noise, masking the temporal profile of the generating pulse. We solved this problem by developing a mathematical method involving the derivative of the autocovariance function to recover excellent approximations of the underlying pulses, significantly extending the analysis of this type of stochastic processes. When the method is applied to spontaneous mouse EEG sampled at $5$ kHz during the sleep-wake cycle, specific patterns -- called $\Psi$-patterns -- characterizing NREM sleep, REM sleep, and wakefulness are revealed. $\Psi$-patterns can be understood theoretically as \textit{power density in the time domain} and correspond to combinations of generating pulses at different time scales. Remarkably, we report the first EEG wakefulness-specific feature, which corresponds to an ultra-fast ($\sim 1$ ms) transient component of the observed patterns. By shifting the paradigm of EEG genesis from oscillators to random pulse generators, our theoretical framework pushes the boundaries of traditional Fourier-based EEG analysis, paving the way for new insights into the arrhythmic components of neural dynamics.Comment: Original research manuscript in PDF format, 46 pages long, with 13 figures and one tabl

Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads

Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria.With exception of XH and JC, all authors were supported by the FP7 Project ULIXES (FP7-KBBE-2010-266473). This work was further funded by grant BIO2011-25012 from the Spanish Ministry of the Economy and Competitiveness. FM was supported by Università degli Studi di Milano, European Social Fund (FSE) and Regione Lombardia (contract BDote Ricerca^). DD acknowledges support of KAUST, King Abdullah University of Science and Technology. PG acknowledges the support of the European Commission through the project Kill-Spill (FP7, Contract Nr 312139).Peer Reviewe

Application as absorbents of natural and functionalized Brazilian bentonite in Pb2+ adsorption: Equilibrium, kinetic, pH, and thermodynamic effects

AbstractThe capacities of natural and modified Brazilian bentonite samples as adsorbents to remove lead were investigated under several conditions in batch and column methods. The raw material, natural bentonite, was modified by anchorament of 3-aminopropyltrietoxisilane (APS) and 3,2-aminoethylaminopropyltrimetoxisilane (AEAPS) in the surface of component minerals of bentonite sample. Adsorption behavior of three bentonite types was strongly depending on pH of adsorbate solution, contact time adsorbent/adsorbate, and initial concentration of metal. The maximum adsorption capacities of bentonite types were 20.6843, 27.6524, and 29.5413mgg−1 for natural, bentonite functionalized by APS, and bentonite functionalized by AEAPS, respectively. The results were confirmed by column method and show that the adsorption process of materials accorded with Sips and Langmuir isotherm models. The pseudo-second-order model simulation was also introduced to reveal the principles of the lead removal. The exothermic enthalpic values reflected a favorable energetic process for lead atoms anchored in the material surfaces. The original and modified bentonite samples were characterized by elemental analysis, scanning electron microscopy, and X-ray diffraction powder. The negative Gibbs free energy results supported the spontaneity of three adsorption reactions with Pb2+

Design of mine-used intrinsically safe wireless through-the-earth communication system

The paper introduced structure and key technologies of mine-used intrinsically safe wireless through-the-earth communication system，and analyzed working principle of the system. The system uses low-frequency electromagnetic radiation technology, digital communication technology and intrinsically safe power supply technology, which has characteristics of smaller volume, lighter weight and easy operation. The test results of prototype show that the system has realized two-way through-the-earth communication for 50 m with communication rate of about 150 bit/s and bit error rate of no larger than 0.2 %, and has a certain practical valu

Comparative Genomics of a Bovine Mycobacterium tuberculosis Isolate and Other Strains Reveals Its Potential Mechanism of Bovine Adaptation

The Mycobacterium tuberculosis complex causes tuberculosis (TB) in humans and other animal species, but Mycobacterium tuberculosis has a distinct host preference to humans. The present study aimed to determine whether a bovine M. tb strain 1458 has evolved some genetic properties in their genome that might be associated with their bovine adaptation. The genome of the M. tb strain 1458 was sequenced and subjected to an extensive comparative genomic analysis. A phylogenetic analysis showed that strain 1458 is most closely related to a Chinese M. tb strain, CCDC5079, of the same Beijing family. Compared with three human M. tb Beijing family strains, the strain 1458 has the fewest unique genes. However, there are most (21) IS6110 insertion sequences in the strain 1458 genome at either intragenic or intergenic sites, resulting in the interruption of 11 genes including three PPE family-encoding genes (PPE16, PPE38, and PPE59). Only the strain 1458 genome has the upstream insertion in esxS and phoP genes. PCR confirmed four upstream insertions and qPCR determined that transcription of esxS, phoP, dnaN, and ctpD genes differed significantly between M. tb strain 1458 and H37Rv or M. bovis. A Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the genes affected by non-synonymous SNPs are enriched in RNA polymerase. Moreover, 127 of the 133 unique SNPs in strain 1458 are either different to those in the M. bovis genome. In conclusion, some critical genes responsible for bacterial virulence and immunogenicity were interrupted in the genome of bovine M. tb strain 1458 by IS insertions and non-synonymous SNPs, which might contribute to its bovine adaptation, and the modification of its virulence and immunogenicity in cattle

Genomic insights into the evolution of <i>Echinochloa</i> species as weed and orphan crop

As one of the great survivors of the plant kingdom, barnyard grasses (Echinochloa spp.) are the most noxious and common weeds in paddy ecosystems. Meanwhile, at least two Echinochloa species have been domesticated and cultivated as millets. In order to better understand the genomic forces driving the evolution of Echinochloa species toward weed and crop characteristics, we assemble genomes of three Echinochloa species (allohexaploid E. crus-galli and E. colona, and allotetraploid E. oryzicola) and re-sequence 737 accessions of barnyard grasses and millets from 16 rice-producing countries. Phylogenomic and comparative genomic analyses reveal the complex and reticulate evolution in the speciation of Echinochloa polyploids and provide evidence of constrained disease-related gene copy numbers in Echinochloa. A population-level investigation uncovers deep population differentiation for local adaptation, multiple target-site herbicide resistance mutations of barnyard grasses, and limited domestication of barnyard millets. Our results provide genomic insights into the dual roles of Echinochloa species as weeds and crops as well as essential resources for studying plant polyploidization, adaptation, precision weed control and millet improvements