Detecting event-related recurrences by symbolic analysis: Applications to human language processing

Quasistationarity is ubiquitous in complex dynamical systems. In brain dynamics there is ample evidence that event-related potentials reflect such quasistationary states. In order to detect them from time series, several segmentation techniques have been proposed. In this study we elaborate a recent approach for detecting quasistationary states as recurrence domains by means of recurrence analysis and subsequent symbolisation methods. As a result, recurrence domains are obtained as partition cells that can be further aligned and unified for different realisations. We address two pertinent problems of contemporary recurrence analysis and present possible solutions for them.Comment: 24 pages, 6 figures. Draft version to appear in Proc Royal Soc

Detection of fixed points in spatiotemporal signals by clustering method

We present a method to determine fixed points in spatiotemporal signals. A 144-dimensioanl simulated signal, similar to a Kueppers-Lortz instability, is analyzed and its fixed points are reconstructed.Comment: 3 pages, 3 figure

A Tonal Analysis of Gurung, with Separate Systems for Register and Contour Pitch Features

An earlier analysis of Gurung, by Burton-Page in BSOAS, 17/1, 1955, put forward a single system, of two terms, for the word unit in the dialect spoken in Ghandrung: tones 1 and 2; the present analysis of the Gurung of a speaker from the centre of the Gurung area differs from Burton-Page's in that it distinguishes two tone systems: a two-term system (tones 1 and 2) for a difference in pitch register and a further two-term system (tones A and B) for a difference in pitch contour. Support for separating register-pitch and contour-pitch differences comes from three associated features, aspiration, phonation and voice: they apply to the register distinction but not to the contour distinction. Further support comes from comparing this tonal analysis with an identical analysis of a closely related language, Tamang, and also with the two-term system put forward for the word in Tibetan

How clumpy is my image? Evaluating crowdsourced annotation tasks

13th UK Workshop on Computational Intelligence (UKCI), Guildford, UK, 9-11 September 2013This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.The use of citizen science to obtain annotations from multiple annotators has been shown to be an effective method for annotating datasets in which computational methods alone are not feasible. The way in which the annotations are obtained is an important consideration which affects the quality of the resulting consensus estimates. In this paper, we examine three separate approaches to obtaining scores for instances rather than merely classifications. To obtain a consensus score annotators were asked to make annotations in one of three paradigms: classification, scoring and ranking. A web-based citizen science experiment is described which implements the three approaches as crowdsourced annotation tasks. The tasks are evaluated in relation to the accuracy and agreement among the participants using both simulated and real-world data from the experiment. The results show a clear difference in performance between the three tasks, with the ranking task obtaining the highest accuracy and agreement among the participants. We show how a simple evolutionary optimiser may be used to improve the performance by reweighting the importance of annotators

Aerobic Bacterial Catabolism of Dimethylsulfoniopropionate

ABSTRACT. Dimethylsulfoniopropionate (DMSP) is an organosulfur zwitterion produced by various marine algae and Bacteria as an osmolyte, cryoprotectant, defence molecule and anti-oxidant. In the marine environment in particular, it can be degraded by the Bacteria in various ways. In this chapter we cover the biochemistry and physiology of the various pathways of DMSP catabolism, including the three core enzymes DMSP dethiomethylase (EC 4.4.1.3, the so-called “DMSP lyase”), DMSP demethylase (EC 2.1.1.269) and DMSP CoA transferase/lyase (EC 2.3.1.x). Six isoenzyme classes of DMSP dethiomethylase have been purified and confirmed in marine Bacteria thus far, with a further isoenzyme found in algae that may also occur in Bacteria – these are all discussed in detail. Methodologies for enzyme assays and the synthesis of DMSP hydrochloride are given, including those for radio- and stable-isotope labelling

Bacterial Metabolism of C1 Sulfur Compounds

The metabolism of C1 organosulfur compounds by the Bacteria is important in the biogeochemical cycling of sulfur and carbon, and in climate regulation in terms of mediating release of e.g. dimethylsulfide from the oceans. Herein we review the canon of work on the metabolism of dimethysulfide, dimethylsulfoxide, dimethylsulfone, methanesulfonate, dimethyldisulfide and methanethiol, in terms of dissimilation to formaldehyde or carbon dioxide when used as carbon and energy sources by methylotrophs or autotrophs; oxidation to sulfite prior to assimilation as sulfur sources, and use as respiratory terminal electron acceptors. We discuss the enzymology of the metabolism of these compounds and propose a revision to the Enzyme Commission classification to some of them where multiple enzymes are clearly grouped under one name at present. We also provide methodologies for enzyme assays, for the safe handling and quantification of these compounds, and for the synthesis of carbon-14, carbon-11, sulfur-34 and sulfur-34 compounds for use in physiological and ecological studies

An evaluation of Thiomicrospira, Hydrogenovibrio and Thioalkalimicrobium: reclassification of 4 species of Thiomicrospira to each Thiomicrorhabdus gen. nov. and Hydrogenovibrio, and reclassification of all 4 species of Thioalkalimicrobium to Thiomicrospira.

Thiomicrospira spp. are small sulfur-oxidising chemolithoautotrophic members of the Gammaproteobacteria. Whilst the type species Tms. pelophila and closely related Tms. thyasirae exhibit canonical spiral morphology under sub-optimal growth conditions, most species are vibrios or rods. The 16S rRNA gene diversity is vast, with identities as low as 91.6 % to Tms. pelophila versus Tms. frisia, for example. Thiomicrospira was examined with closely related genera Hydrogenovibrio and Thioalkalimicrobium and, to rationalise organisms on the basis of the 16S rRNA gene phylogeny, physiology and morphology, we reclassify Tms. kuenenii, Tms. crunogena, Tms. thermophila and Tms. halophila to Hydrogenovibrio kuenenii comb. nov., H. crunogenus corrig. comb. nov., H. thermophilus corrig. comb. nov., and H. halophilus corrig. comb. nov. We reclassify Tms. frisia, Tms. arctica, Tms. psychrophila and Tms. chilensis to Thiomicrorhabdus gen. nov., as Tmr. frisia comb. nov., Tmr. arctica comb. nov., Tmr. psychrophila comb. nov. and Tmr. chilensis comb. nov. – the type species of Thiomicrorhabdus is Tmr. frisia. We demonstrate Thioalkalimicrobium spp. fall in the genus Thiomicrospira sensu stricto, thus reclassifying them to Tms. aerophila corrig. comb. nov., Tms. microaerophila corrig. comb. nov., Tms. cyclica corrig. comb. nov.and Tms. sibirica corrig. comb. nov. We provide emended descriptions of the genera Thiomicrospira and Hydrogenovibrio and of Tms. thyasirae