Systematic experimental exploration of bifurcations with non-invasive control

We present a general method for systematically investigating the dynamics and bifurcations of a physical nonlinear experiment. In particular, we show how the odd-number limitation inherent in popular non-invasive control schemes, such as (Pyragas) time-delayed or washout-filtered feedback control, can be overcome for tracking equilibria or forced periodic orbits in experiments. To demonstrate the use of our non-invasive control, we trace out experimentally the resonance surface of a periodically forced mechanical nonlinear oscillator near the onset of instability, around two saddle-node bifurcations (folds) and a cusp bifurcation.Comment: revised and extended version (8 pages, 7 figures

Oil Prices and Stock Market Performance: A Five Country Comparative Analysis

This presentation looks at the potential correlation between spot oil prices and daily stock market performance in five countries: Iran, Singapore, Saudi Arabia, Thailand, and Indonesia. Such a correlation is of great relevance to investment analysts involved in the equity markets in these countries. Based on quantitative study of oil prices and stock market index data for each country during the last five years this study will calculate a coefficient that indicates how much oil price changes influence stock market valuation. This study draws on published research in the field and adjusts the oil price data according to fluctuations in the exchange rate between the dollar and the native currency of each country so as to eliminate the “noise” of often volatile foreign currency markets

Employees, sustainability and motivation: Increasing employee engagement by addressing sustainability and corporate social responsibility

An increasing number of academic studies indicate that we as humans are exploiting the planet earth to an extent that is no longer bearable. Put differently, we are actively destroying our very own basis of existence, especially considering the generations to come. It is therefore becoming increasingly significant for companies to develop more social and environmentally friendly ways to produce and distribute their products and services. Moreover, this is reinforced by the rising public awareness of sustainability issues. Apart from this, demographic changes make it increasingly difficult to attract and hire enough qualified employees. Besides, many employees all over the world lack a deeper meaning in what they are doing and consequently job-related motivation and engagement is alarmingly low. Such an issue is signally relevant in particular for the hospitality industry, since hospitality jobs are considered to demand a high performance but are rather poorly paid, while at the same time the industry operates with a high labour intensity, which leads to a substantially high staff turnover rate. The combination of the problems mentioned may in fact have a comprehensive solution. The approach is to actively involve employees in sustainability and corporate social responsibility (CSR) issues and in this way lead employees to the perception of their jobs as being meaningful. Consequentially, increased engagement is expected, which in turn is positively related to business performance and profitability. This research proposes an employee-focused process model that companies can exploit as a guideline towards greater sustainability, CSR and engagement.Keywords: employee motivation, sustainability, corporate social responsibility, staff engagemen

Unusual Metabolism and Hypervariation in the Genome of a Gracilibacterium (BD1-5) from an Oil-Degrading Community.

The candidate phyla radiation (CPR) comprises a large monophyletic group of bacterial lineages known almost exclusively based on genomes obtained using cultivation-independent methods. Within the CPR, Gracilibacteria (BD1-5) are particularly poorly understood due to undersampling and the inherent fragmented nature of available genomes. Here, we report the first closed, curated genome of a gracilibacterium from an enrichment experiment inoculated from the Gulf of Mexico and designed to investigate hydrocarbon degradation. The gracilibacterium rose in abundance after the community switched to dominance by Colwellia Notably, we predict that this gracilibacterium completely lacks glycolysis, the pentose phosphate and Entner-Doudoroff pathways. It appears to acquire pyruvate, acetyl coenzyme A (acetyl-CoA), and oxaloacetate via degradation of externally derived citrate, malate, and amino acids and may use compound interconversion and oxidoreductases to generate and recycle reductive power. The initial genome assembly was fragmented in an unusual gene that is hypervariable within a repeat region. Such extreme local variation is rare but characteristic of genes that confer traits under pressure to diversify within a population. Notably, the four major repeated 9-mer nucleotide sequences all generate a proline-threonine-aspartic acid (PTD) repeat. The genome of an abundant Colwellia psychrerythraea population has a large extracellular protein that also contains the repeated PTD motif. Although we do not know the host for the BD1-5 cell, the high relative abundance of the C. psychrerythraea population and the shared surface protein repeat may indicate an association between these bacteria.IMPORTANCE CPR bacteria are generally predicted to be symbionts due to their extensive biosynthetic deficits. Although monophyletic, they are not monolithic in terms of their lifestyles. The organism described here appears to have evolved an unusual metabolic platform not reliant on glucose or pentose sugars. Its biology appears to be centered around bacterial host-derived compounds and/or cell detritus. Amino acids likely provide building blocks for nucleic acids, peptidoglycan, and protein synthesis. We resolved an unusual repeat region that would be invisible without genome curation. The nucleotide sequence is apparently under strong diversifying selection, but the amino acid sequence is under stabilizing selection. The amino acid repeat also occurs in a surface protein of a coexisting bacterium, suggesting colocation and possibly interdependence

Control-based continuation of unstable periodic orbits

Copyright © 2010 American Society of Mechanical Engineers (ASME)We present an experimental procedure to track periodic orbits through a fold (saddle-node) bifurcation and demonstrate it with a parametrically excited pendulum experiment where the tracking parameter is the amplitude of the excitation. Specifically, we track the initially stable period-one rotation of the pendulum through its fold bifurcation and along the unstable branch. The fold bifurcation itself corresponds to the minimal amplitude that supports sustained rotation. Our scheme is based on a modification of time-delayed feedback in a continuation setting and we show for an idealized model that it converges with the same efficiency as classical proportional-plus-derivative control

Journalismus rentiert nicht: Medienförderung (Interview)

Der Bundesrat ist mit seinem Gesetz über elektronische Medien in der Vernehmlassung aufgelaufen. Für Medienforscher Otfried Jarren der Anfang einer Debatte, an deren Ende pragmatische Lösungen stehen müssen, die den Medien das Überleben sichern. Denn: "Medienpolitik ist Gesellschaftspolitik"

Design and experimental setup of a new concept of an aerosol-on-demand print head

Aerosol jet printing is an alternative to inkjet printing, the currently most established fabrication technique for printed electronics, with the benefits of small feature sizes, more homogeneous thickness of the printed layers, and the possibility to print on 3D structures. Printers are available on the market, in which the aerosol is generated outside of the print heads, with the disadvantage that only continuous operation is possible due to the long distance between atomization unit and print head. We report on the development and validation of a new integrated principle, with the atomization of the ink directly inside the print head. This enables a compact design, printing in all spatial directions and jet-on-demand operation. Based on fluid dynamic simulations, an optimized integrated print head design was developed, and fabricated. First tests have been performed in a preliminary laboratory test setup. The successful focusing of the aerosol to approximately 1/7 of the spread of the non-focused aerosol spray was validated in experiments, thus confirming the operating principle of the new aerosol-on-demand print head

Li5SnP3: a member of the series Li10+4xSn2−xP6 for x=0 comprising the fast lithium‐ion conductors Li8SnP4 (x=0.5) and Li14SnP6 (x=1)

The targeted search for suitable solid‐state ionic conductors requires a certain understanding of the conduction mechanism and the correlation of the structures and the resulting properties of the material. Thus, the investigation of various ionic conductors with respect to their structural composition is crucial for the design of next‐generation materials as demanded. We report here on Li(5)SnP(3) which completes with x=0 the series Li(10+4x )Sn(2−x )P(6) of the fast lithium‐ion conductors α‐ and β‐Li(8)SnP(4) (x=0.5) and Li(14)SnP(6) (x=1). Synthesis, crystal structure determination by single‐crystal and powder X‐ray diffraction methods, as well as (6)Li, (31)P and (119)Sn MAS NMR and temperature‐dependent (7)Li NMR spectroscopy together with electrochemical impedance studies are reported. The correlation between the ionic conductivity and the occupation of octahedral and tetrahedral sites in a close‐packed array of P atoms in the series of compounds is discussed. We conclude from this series that in order to receive fast ion conductors a partial occupation of the octahedral vacancies seems to be crucial

Genetically encoded betaxanthin-based small-molecular fluorescent reporter for mammalian cells

We designed and engineered a dye production cassette encoding a heterologous pathway, including human tyrosine hydroxylase and Amanita muscaria 4,5-DOPA dioxygenase, for the biosynthesis of the betaxanthin family of plant and fungal pigments in mammalian cells. The system does not impair cell viability, and can be used as a non-protein reporter system to directly visualize the dynamics of gene expression by profiling absorbance or fluorescence in the supernatant of cell cultures, as well as for fluorescence labeling of individual cells. Pigment profiling can also be multiplexed with reporter proteins such as mCherry or the human model glycoprotein SEAP (secreted alkaline phosphatase). Furthermore, absorbance measurement with a smartphone camera using standard application software enables inexpensive, low-tech reporter quantification