Experimental investigation of MHD impact on argon plasma flows by variation of magnetic flux density

The interaction between a probe body and argon plasma flow is investigated to examine to what extent the probe head temperature and the bow shock distance can be influenced by applying a strong magnetic field. The experiments are performed using a strong permanent magnet installed inside a probe body with a spherical, coated probe head. Former investigations showed strong influence on the bow shock geometry but also on the inflow plasma jet. Several boundary conditions have been varied to evaluate their influence toward the experiment. For an uncoated probe head the measured MHD impact was found to be of the same order of magnitude as for the coated case. Electrical isolation of the probe toward the vacuum chamber yielded only slight influence. The variation of the field strength was realized by changing the amount of magnet segments installed. Pictures were analyzed to minute the MHD interaction for each test case. It was found that the bow shock distance increased and the temperature of the probe head decreased while increasing the magnetic field density. This analysis precedes a thorough characterization of the plasma condition

Metagenomic binning of a marine sponge microbiome reveals unity in defense but metabolic specialization

Marine sponges are ancient metazoans that are populated by distinct and highly diverse microbial communities. In order to obtain deeper insights into the functional gene repertoire of the Mediterranean sponge Aplysina aerophoba, we combined Illumina short-read and PacBio long-read sequencing followed by un-targeted metagenomic binning. We identified a total of 37 high-quality bins representing 11 bacterial phyla and two candidate phyla. Statistical comparison of symbiont genomes with selected reference genomes revealed a significant enrichment of genes related to bacterial defense (restriction-modification systems, toxin-antitoxin systems) as well as genes involved in host colonization and extracellular matrix utilization in sponge symbionts. A within-symbionts genome comparison revealed a nutritional specialization of at least two symbiont guilds, where one appears to metabolize carnitine and the other sulfated polysaccharides, both of which are abundant molecules in the sponge extracellular matrix. A third guild of symbionts may be viewed as nutritional generalists that perform largely the same metabolic pathways but lack such extraordinary numbers of the relevant genes. This study characterizes the genomic repertoire of sponge symbionts at an unprecedented resolution and it provides greater insights into the molecular mechanisms underlying microbial-sponge symbiosis

Re-examining path dependence in the digital age: the evolution of connected car business models

Proliferating digitalization affects the evolution of business models across contexts and challenges firms’ established innovation trajectories. Prior work on organizational path dependence suggests that firms experience decreasing option spaces over time and ultimately arrive at lock-in situations that prevent them from reacting to changing environmental conditions. Contemporary business practice, however, challenges these assumptions, as firms—even industrial-age incumbents—appear to be able to escape lock-ins and restore choices. One potential explanation for this could be the flexible nature of digital technologies that are increasingly integrated into business models during digitalization. To explore how and why this process affects organizational path dependence, we conducted a longitudinal multiple case study on connected car business models. We derive four business model archetypes adopted by different companies in the automotive industry and by new entrants, and we describe their evolution over time. We find that the growing integration of digital technologies into business models increases the number of possible pathways and can help to break path-dependent behavior. Based on our findings, we challenge and extend established knowledge on organizational path dependence with regard to key tenets, such as initial conditions and lock-ins, and provide a nuanced perspective on path dependence's resource- and cognition-based foundations.info:eu-repo/semantics/publishedVersio

Juvenile immune system activation induces a costly upregulation of adult immunity in field crickets Gryllus campestris

Inducible immune defence may allow organisms a state-dependent upregulation of costly immunity in order to minimize the risk of anticipated future parasitism. The basic costs of elevated immune activity might involve a reduction in other fitness-related traits as well as an increased risk of immunopathology. In male field crickets Gryllus campestris we experimentally investigated the condition-dependent effects of immune system activation in nymphs on immunity and physiological condition during adulthood. Following a nymphal injection of bacterial lipopolysaccharides, adult males showed significantly elevated levels of two major immune parameters, i.e. haemolymph antibacterial activity and the concentration of prophenoloxidase (proPO). By contrast, the active enzyme, phenoloxidase (PO), did not increase, suggesting a strategic long-term upregulation of the inactive proenzyme proPO only. This may help avoid the cytotoxic effects associated with high standing levels of the active enzyme. The nymphal immune insult further caused a reduction in adult haemolymph protein load, suggesting a long-term decline in overall metabolic condition. Nymphal food availability positively affected adult lysozyme activity, while PO and proPO concentrations were not affected. Our data thus suggest the long-term upregulation of immunity in response to antigenic cues as an adaptive, yet costly, invertebrate strategy to improve resistance to future parasitism