A novel pathogenic taxon of the Mycobacterium tuberculosis complex, Canetti: characterization of an exceptional isolate from Africa

In an attempt to characterize an unusual mycobacterial strain isolated from a 2-year-old Somali patient with lymphadenitis, we applied various molecular methods not previously used for the taxonomic classification of mycobacteria. This isolate, designated So93, did not differ from Mycobacterium tuberculosis in the biochemical tests and in its 16S rRNA sequence, but produced smooth and glossy colonies, which is highly exceptional for this species. This smooth phenotype was unstable and switched nonreversibly to a rough colony morphology with a low frequency. The two colony types were equally virulent for the guinea pig, exhibiting characteristic tuberculous disease. Both morphotypes had shorter generation times than the M. tuberculosis reference laboratory strain H37Rv and clinical isolates of M. tuberculosis and Mycobacterium bovis. Furthermore, the So93 isolate differed from all M. tuberculosis complex strains described thus far by having only a single copy of insertion sequence IS1081, an unusual composition of the direct repeat cluster, and a characteristic phenolic glycolipid and lipooligosaccharide. This glycolipid had previously been observed only in a smooth isolate of M. tuberculosis obtained in 1969 by Canetti in France. Analysis of the Canetti strain showed that it shared virtually all genetic properties characteristic of So93, distinguishing these two strains from the known M. tuberculosis complex taxa, M. tuberculosis, Mycobacterium africanum, M. bovis, and Mycobacterium microti. The natural reservoir, host range, and mode of transmission of the group of bacteria described in this paper are presently unknown. This study, partly based on not previously used molecular criteria, supports the idea that the established members within the M. tuberculosis complex and the newly described Canetti grouping should be regarded as a single species, which likely will be designated "M. tuberculosis".     

Random Pattern and Frequency Generation Using a Photonic Reservoir Computer with Output Feedback

Reservoir computing is a bio-inspired computing paradigm for processing time dependent signals. The performance of its analogue implementations matches other digital algorithms on a series of benchmark tasks. Their potential can be further increased by feeding the output signal back into the reservoir, which would allow to apply the algorithm to time series generation. This requires, in principle, implementing a sufficiently fast readout layer for real-time output computation. Here we achieve this with a digital output layer driven by a FPGA chip. We demonstrate the first opto-electronic reservoir computer with output feedback and test it on two examples of time series generation tasks: frequency and random pattern generation. We obtain very good results on the first task, similar to idealised numerical simulations. The performance on the second one, however, suffers from the experimental noise. We illustrate this point with a detailed investigation of the consequences of noise on the performance of a physical reservoir computer with output feedback. Our work thus opens new possible applications for analogue reservoir computing and brings new insights on the impact of noise on the output feedback.     

Laser polishing and 2PP structuring of inside microfluidic channels in fused silica

This study presents the development of post-processing steps for microfluidics fabricated with selective laser etching (SLE) in fused silica. In a first step, the SLE surface—even inner walls of microfluidic channels—can be smoothed by laser polishing. In addition, two-photon polymerization (2PP) can be used to manufacture polymer microstructures and microcomponents inside the microfluidic channels. The reduction in the surface roughness by laser polishing is a remelting process. While heating the glass surface above softening temperature, laser radiation relocates material thanks to the surface tension. With laser polishing, the RMS roughness of SLE surfaces can be reduced from 12 µm down to 3 nm for spatial wavelength λ < 400 µm. Thanks to the laser polishing, fluidic processes as well as particles in microchannels can be observed with microscopy. A manufactured microfluidic demonstrates that SLE and laser polishing can be combined successfully. By developing two-photon polymerization (2PP) processing in microchannels we aim to enable new applications with sophisticated 3D structures inside the microchannel. With 2PP, lenses with a diameter of 50 µm are processed with a form accuracy rms of 70 nm. In addition, this study demonstrates that 3D structures can be fabricated inside the microchannels manufactured with SLE. Thanks to the combination of SLE, laser polishing and 2PP, research is pioneering new applications for microfluidics made of fused silica.     

High‐resolution imaging of nanoparticle bimetallic catalysts supported on mesoporous silica

Although conventional high‐resolution transmission electron microscopy is a powerful method for the elucidation of the structure of mesoporous solids (diameter of pores from 1.5 to 20 nm), it is far less capable than high‐resolution scanning transmission electron microscopy in identifying the spatial distribution of nanocrystals of catalysts encapsulated within the mesopores. Using high‐angle annular dark‐field imaging (either in a 100 or 300 keV STEM system), it is possible to locate precisely individual bimetallic nanoparticles (Ag₃Ru₁₀, Cu₄Ru₁₂ and Pd₆Ru₆ hydrogenation catalysts) supported on mesoporous silica, to determine their size distribution, and to record their characteristic X‐ray emission maps. It is also established that there is little tendency for elemental fragmentation of the bimetallic catalysts, all of which were prepared by decarbonylating, by thermolysis, precursor cluster carbonylate anions: [Ag₃Ru₁₀C₂(CO)₂₈Cl]⁻, [Ru₆C(CO)₁₆Cu₂Cl]²⁻ and [Ru₆Pd₆(CO)₂₄]²⁻. This revised version was published online in July 2006 with corrections to the Cover Date.     

Self, identity, and globalization in times of uncertainty: A dialogical analysis.

Our era is witnessing an increasing impact of globalization on self and identity and at the same time a growing uncertainty. The experience of uncertainty motivates individuals and groups to find local niches for identity construction. This article's central tenet is that the processes of globalization and localization, as globalization's counterforce, require a dialogical conceptualization of self and identity in which global and local voices are involved in continuous interchanges and negotiations. This tenet is elaborated along 2 lines of argument. First, 3 factors are described as crucial to understanding the processes of globalization and localization on the individual level: the increasing number of voices and countervoices, the role of social power, and the role of emotions. Second, the authors argue that the apparent tension between the widening horizons of globalization and the need for local niches requires acknowledgment of the pervasive influence of biologically based needs for stability, safety, and security. Finally, the authors propose studying self and identity on 3 levels--individual, local, and global--and some lines of research at the interface of these levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation between OSH and ergonomics: a 'mother-daughter' or 'sister-sister' relation?

Despite the growing importance of ergonomics and ergonomists worldwide, the position of ergonomics in companies is often not clear. Today, in many countries ergonomics is mainly (or even only) associated with the reduction of risks of work-related musculoskeletal disorders (WMSDs). Therefore, many companies consider ergonomics a part of occupational safety and health (OSH) that focuses mainly on the reduction of risks. This paper aims to analyse the links between occupational ergonomics and OSH. The position of occupational ergonomics in legislation, the presence of ergonomics in OSH networks, and the position of ergonomics in OSH company services are discussed. In addition, the added value of ergonomics to companies is examined. From these discussions, it becomes clear that ergonomics should be part of the OSH policy of companies, and should be integrated into today's company strategies to improve labour conditions. If ergonomics is considered as a discipline in its own right, a clear legislative context should be developed that goes beyond voluntary guidelines and the goodwill of employers, and necessitates the presence of ergonomics professionals in companies.     

Recurrent kernel machines: computing with infinite echo state networks

Echo state networks (ESNs) are large, random recurrent neural networks with a single trained linear readout layer. Despite the untrained nature of the recurrent weights, they are capable of performing universal computations on temporal input data, which makes them interesting for both theoretical research and practical applications. The key to their success lies in the fact that the network computes a broad set of nonlinear, spatiotemporal mappings of the input data, on which linear regression or classification can easily be performed. One could consider the reservoir as a spatiotemporal kernel, in which the mapping to a high-dimensional space is computed explicitly. In this letter, we build on this idea and extend the concept of ESNs to infinite-sized recurrent neural networks, which can be considered recursive kernels that subsequently can be used to create recursive support vector machines. We present the theoretical framework, provide several practical examples of recursive kernels, and apply them to typical temporal tasks.