627 research outputs found
Analyzing critical propagation in a reaction-diffusion-advection model using unstable slow waves
The effect of advection on the critical minimal speed of traveling waves is
studied. Previous theoretical studies estimated the effect on the velocity of
stable fast waves and predicted the existence of a critical advection strength
below which propagating waves are not supported anymore. In this paper, the
critical advection strength is calculated taking into account the unstable slow
wave solution. Thereby, theoretical results predict, that advection can induce
stable wave propagation in the non-excitable parameter regime, if the advection
strength exceeds a critical value. In addition, an analytical expression for
the advection-velocity relation of the unstable slow wave is derived.
Predictions are confirmed numerically in a two-variable reaction-diffusion
model.Comment: 11 pages, 8 figure
On the inverse optimal control problem in manual control systems
Inverse optimal control in manual control system
Modern control system theory and human control functions
Optimal control system theory applied to manual control systems - adaptive control - mathematical model
Tension dynamics and viscoelasticity of extensible wormlike chains
The dynamic response of prestressed semiflexible biopolymers is characterized
by the propagation and relaxation of tension, which arises due to the near
inextensibility of a stiff backbone. It is coupled to the dynamics of contour
length stored in thermal undulations, but also to the local relaxation of
elongational strain. We present a systematic theory of tension dynamics for
stiff yet extensible wormlike chains. Our results show that even moderate
prestress gives rise to distinct Rouse-like extensibility signatures in the
high-frequency viscoelastic response.Comment: 4 pages, 1 figure; corrected typo
The prebiotic evolutionary advantage of transferring genetic information from RNA to DNA.
In the early 'RNA world' stage of life, RNA stored genetic information and catalyzed chemical reactions. However, the RNA world eventually gave rise to the DNA-RNA-protein world, and this transition included the 'genetic takeover' of information storage by DNA. We investigated evolutionary advantages for using DNA as the genetic material. The error rate of replication imposes a fundamental limit on the amount of information that can be stored in the genome, as mutations degrade information. We compared misincorporation rates of RNA and DNA in experimental non-enzymatic polymerization and calculated the lowest possible error rates from a thermodynamic model. Both analyses found that RNA replication was intrinsically error-prone compared to DNA, suggesting that total genomic information could increase after the transition to DNA. Analysis of the transitional RNA/DNA hybrid duplexes showed that copying RNA into DNA had similar fidelity to RNA replication, so information could be maintained during the genetic takeover. However, copying DNA into RNA was very error-prone, suggesting that attempts to return to the RNA world would result in a considerable loss of information. Therefore, the genetic takeover may have been driven by a combination of increased chemical stability, increased genome size and irreversibility
Human performance prediction in man-machine systems. Volume 1 - A technical review
Tests and test techniques for human performance prediction in man-machine systems task
Viral infection identifies micropeptides differentially regulated in smORF-containing lncRNAs
Viral infection leads to a robust cellular response whereby the infected cell produces hundreds of molecular regulators to combat infection. Currently, non-canonical components, e.g., long noncoding RNAs (lncRNAs) have been added to the repertoire of immune regulators involved in the antiviral program. Interestingly, studies utilizing next-generation sequencing technologies show that a subset of the >10,000 lncRNAs in the mammalian genome contain small open reading frames (smORFs) associated with active translation, i.e., many lncRNAs are not noncoding. Here, we use genome-wide high-throughput methods to identify potential micropeptides in smORF-containing lncRNAs involved in the immune response. Using influenza as a viral infection model, we performed RNA-seq and ribosome profiling to track expression and translation of putative lncRNAs that may encode for peptides and identify tens of potential candidates. Interestingly, many of these peptides are highly conserved at the protein level, strongly suggesting biological relevance and activity. By perusing publicly available data sets, four potential peptides of interest seem common to stress induction and/or are highly conserved; potential peptides from the MMP24-AS1, ZFAS1, RP11-622K12.1, and MIR22HG genes. Interestingly, using an antibody against the potential peptide encoded by MIR22HG RNA, we show that the peptide is stably expressed in the absence of infection, and upregulated in response to infection, corroborating the prediction of the ribosome profiling results. These data show the utility of perturbation approaches in identifying potentially relevant novel molecules encoded in the genome
Human performance prediction in man-machine systems. Part 2 - The test catalog
Human performance prediction in man machine systems - test catalog table
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