Обработка сигналов домен-акустическим процессором в автокорреляционном режиме

Аналізується відношення сигнал/шум, яке може бути досягнуте під час оброблення сигналів домен-акустичним процесором. Показано, що якість обробки сигналів вказаним методом в ідеальному випадку визначається якістю цих первинних сигналів, при цьому за умови, що сигнал запису формується малошумним по- тужним генератором, то в автокореляцiйному режимі опорний сигнал формується із сигналу, який підлягає обробціIt is analyzed the signal / noise ratio, which can be achieved by the signal processing domain-acoustic processor. It is shown that the quality of signal processing by this method ideally determined by the quality of the primary signals. Provided that the recorded signal is formed by a powerful generator of low-noise, the autocorrelation mode, the reference signal generated from the signal, which is to be processedАнализируется отношение сигнал/шум, которое может быть достигнуто при обработки сигналов домен-акустическим процессором. Показано, что качество обработки сигналов указанным методом в идеальном случае определяется качеством этих первичных сигналов. При условии, что сигнал записи формируется малошумным мощным генератором, в автокорреляционном режиме опорный сигнал формируется из сигнала, который подлежит обработк

Theory of periodic swarming of bacteria: application to Proteus mirabilis

The periodic swarming of bacteria is one of the simplest examples for pattern formation produced by the self-organized collective behavior of a large number of organisms. In the spectacular colonies of Proteus mirabilis (the most common species exhibiting this type of growth) a series of concentric rings are developed as the bacteria multiply and swarm following a scenario periodically repeating itself. We have developed a theoretical description for this process in order to get a deeper insight into some of the typical processes governing the phenomena in systems of many interacting living units. All of our theoretical results are in excellent quantitative agreement with the complete set of available observations.Comment: 11 pages, 8 figure

Education, knowledge, and symbolic form

This article aims to introduce Ernst Cassirer, and his philosophy of symbolic form, to education studies, and, in doing so, to challenge the widespread but deeply flawed views of knowledge and so-called knowledge-based education that have shaped recent education policy in England. After sketching the current educational landscape, and then some of the main lines of flight in Cassirer’s work, time is given to a comparison with Heidegger—a more familiar figure by far in Anglophone philosophy than Cassirer, and who contributed to the displacement of Cassirer—in order to illustrate more clearly Cassirer’s original contribution, in particular to the relationship between knowledge and time. Cassirer’s view of knowledge stands in marked and critical contrast to that which has shaped recent educational reform in England, as he sees knowledge as a productive and expressive matter, and repudiates what I call the ‘building-blocks’ picture of knowledge and the hierarchisation of subject areas

Bacterial Surface Appendages Strongly Impact Nanomechanical and Electrokinetic Properties of Escherichia coli Cells Subjected to Osmotic Stress

The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM) and electrokinetics (electrophoresis). Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus). From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO3, cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (∼700–900 kPa and ∼100–300 kPa respectively). Under similar ionic strength condition, a dramatic ∼50% to ∼70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the intimate relationship between structure/flexibility and charge of bacterial envelope and propensity of bacterium and surface appendages to contract under hypertonic conditions

Обробка сигналів домен-акустичним процесором у авто кореляційному режимі

It is analyzed the signal / noise ratio, which can be achieved by the signal processing domain-acoustic processor. It is shown that the quality of signal processing by this method ideally determined by the quality of the primary signals. Provided that the recorded signal is formed by a powerful generator of low-noise, the autocorrelation mode, the reference signal generated from the signal, which is to be processed.Анализируется отношение сигнал/шум, которое может быть достигнуто при обработки сигналов домен-акустическим процессором. Показано, что качество обработки сигналов указанным методом в идеальном случае определяется качеством этих первичных сигналов. При условии, что сигнал записи формируется малошумным мощным генератором, в автокорреляционном режиме опорный сигнал формируется из сигнала, который подлежит обработке.Аналізується відношення сигнал/шум, яке може бути досягнуте під час оброблення сигналів домен-акустичним процесором. Показано, що якість обробки сигналів вказаним методом в ідеальному випадку визначається якістю цих первинних сигналів, при цьому за умови, що сигнал запису формується малошумним потужним генератором, то в автокореляцiйному режимі опорний сигнал формується із сигналу, який підлягає обробці