Synchronization of organ pipes

We investigate synchronization of coupled organ pipes. Synchronization and reflection in the organ lead to undesired weakening of the sound in special cases. Recent experiments have shown that sound interaction is highly complex and nonlinear, however, we show that two delay-coupled Van-der-Pol oscillators appear to be a good model for the occurring dynamical phenomena. Here the coupling is realized as distance-dependent, or time-delayed, equivalently. Analytically, we investigate the synchronization frequency and bifurcation scenarios which occur at the boundaries of the Arnold tongues. We successfully compare our results to experimental data

Chimera states in complex networks: interplay of fractal topology and delay

Chimera states are an example of intriguing partial synchronization patterns emerging in networks of identical oscillators. They consist of spatially coexisting domains of coherent (synchronized) and incoherent (desynchronized) dynamics. We analyze chimera states in networks of Van der Pol oscillators with hierarchical connectivities, and elaborate the role of time delay introduced in the coupling term. In the parameter plane of coupling strength and delay time we find tongue-like regions of existence of chimera states alternating with regions of existence of coherent travelling waves. We demonstrate that by varying the time delay one can deliberately stabilize desired spatio-temporal patterns in the system.Comment: arXiv admin note: text overlap with arXiv:1603.0017

Chimera states and the interplay between initial conditions and non-local coupling

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Chaos 27, 033110 (2017) and may be found at https://doi.org/10.1063/1.4977866.Chimera states are complex spatio-temporal patterns that consist of coexisting domains of coherent and incoherent dynamics. We study chimera states in a network of non-locally coupled Stuart-Landau oscillators. We investigate the impact of initial conditions in combination with non-local coupling. Based on an analytical argument, we show how the coupling phase and the coupling strength are linked to the occurrence of chimera states, flipped profiles of the mean phase velocity, and the transition from a phase- to an amplitude-mediated chimera state. Chimera states are an example of intriguing partial synchronization patterns appearing in networks of identical oscillators with symmetric coupling scheme. They exhibit a hybrid structure combining coexisting spatial domains of coherent (synchronized) and incoherent (desynchronized) dynamics and were first reported for the model of phase oscillators. Recent studies have demonstrated the emergence of chimera states in a variety of topologies and for different types of individual dynamics. In this paper, the interplay between initial conditions and non-local coupling is studied. We show that, based on an analytical argument incorporating the initial conditions and the range of non-local coupling, the occurrence of phase chimeras can be seen as caused by a phase lag in the coupling. Considering the dynamics of chimera states, our argument shows how “flipped” profiles of the mean phase velocities can be explained by a change of sign of the coupling phase. By this, one can either choose a concave (“upside”) profile of the mean phase velocities or a “flipped” one. Extending our reasoning, we show that this argument intuitively explains the transition from a phase- to an amplitude-mediated chimera state as a result of increasing coupling strength.DFG, 163436311, SFB 910: Kontrolle selbstorganisierender nichtlinearer Systeme: Theoretische Methoden und Anwendungskonzept

A comparison of PCR-based markers for the molecular identification of Sphagnum species of the section Acutifolia

RAPDs, ISJs, ISSRs, ITS and katGs were applied to determine genetic relationships between common Sphagnum species of the section Acutifolia. Twenty populations were genotyped using ten ISJ primers, 12 pairs of katG primers, 10 ISSR and 10 RAPD primers, and a restriction analysis of ITS1 and ITS2. ISSR and katG markers revealed the greatest number of species-specific bands. An analysis of ITS1 and ITS2 regions with restriction enzymes also proved to be a highly effective tool for species identification

A unique late medieval framed purse from New Market (Nowy Targ) square in Wrocław

The paper concerns a ring-framed purse found during rescue excavations conducted on the Nowy Targ square in Wrocław (2010-2012). Such purses have not been present in the Polish archaeological literature and most of the analogies are known from foreign museum collections. Contrary to those specimens, originating primarily from England and the lands of today’s Germany, the Wrocław purse has a wooden frame and it is made of low quality leather. Its biography is interesting. The object was discovered in the layers dated to the 2nd half of the 13th c.-the beginning of the 14th c., while the other known ring-framed purses are much later (end of the 15th c., 16th c.). Olaf Goubitz states that items of such type appear after 1425. However, they are depicted in the so called Codex Manesse dated to 1300-1340, which corresponds with the chronology of the Wrocław find. The indirect analogies as well as all the data suggest that the purse was a homemade product made for self use. Its early date (especially in comparison to other known specimens and most of depictions in iconography) pose a question if the wooden ring-framed purse was a rare cheap imitation of luxury products or if it is an example of common objects intended for everyday use, which only rarely are recorded in archaeological material and written sources. Solving the problem is impossible based on the one individual find. However, it is worth to remember that similar rare, forgotten or “unpreserved” objects can change our image and understanding of the medieval material culture

Relay synchronization in multiplex networks of discrete maps

Complex multiplex networks consist of several subnetwork layers, which interact via pairwise inter-layer connections. Relay synchronization between distant layers which are not directly connected, but only via a relay layer, can be observed in multiplex networks. We study three-layer networks of discrete logistic maps, where each individual layer is a nonlocally coupled ring, and demonstrate scenarios of relay synchronization of complex patterns in the outer layers which interact via an intermediate layer. We find regimes of relay synchronization for chimera states, i.e., patterns of coexisting coherent and incoherent domains, and a transition from phase chimeras to amplitude chimeras for increasing inter-layer coupling. We determine analytically the approximate critical coupling strengths for the existence of phase chimeras

Isolation and characterization of microsatellite loci in Pulsatilla patens (L.) Mill. (Ranunculaceae) a rare and endangered plant species in Europe

Pulsatilla patens is a rare and endangered plant species in many areas of Europe and protected under the Bern Convention and it is listed in Annex II and Annex IV to the Habitats Directive. In this study we developed 12 novel microsatellite loci using via 454 sequencing. We determined 11,220 contigs with a length of 156–11,384 bp. Within this dataset, we identified 319 SSR motifs in 301 contigs. All markers were genotyped on 56 individuals from three populations located in Poland. The number of alleles and expected heterozygosity were 2–12 (mean 3.7) and 0.142–0.820 (0.541 on average) respectively. The markers described in this study will be useful for evaluating genetic diversity of P. patens populations, could be applied to investigate the biological aspects and to develop effective conservation programs for the European populations of this species. Pulsatilla patens (L.) Mill. (Ranunculaceae) is a long-lived perennial herb. It is a lowland species with a circumpolar range, found in all three continents in the northern hemisphere (Hulten and Fries 1986). Pulsatilla patens is widespread in Central and Eastern Europe, with its western range extending to Sweden and Germany (Akeroyd 1993). In North America, the species occurs mostly in the Central and Western United States, in Central and Northwestern Canada and in Eastern Alaska. Pulsatilla patens shows a preference for dry, sun-exposed sites. In Europe, it can be found in thermophilous grasslands and coniferous forest. Within its range in Europe, P. patens is considered to be critically endangered in many areas. The species is protected under the Bern Convention, and it is listed in Annex II and Annex IV to the Habitats Directive (Council of Europe 1979; European Communities 2004) due to a small number of localities, low abundance and the gradual disappearance of populations. The species decline is related to changes in land use, especially in forestry practices where efficient wildfire prevention and termination of cattle grazing in forests have led to the formation of a continuous moss layer or strongly grass dominated vegetation, which severely hinders the regeneration of P. patens (Kalamees et al. 2005). Long-term protection and management plans aimed at preserving P. patens populations should involve habitat and environmental monitoring as well as the quantification of genetic diversity within and among populations. Microsatellite markers, also referred to as simple sequence repeat (SSR) markers, are widely used in ecological studies and can also be employed to investigate the genetic diversity of populations. In this study, we developed nuclear microsatellite markers for P. patens with the involvement of GS Junior next generation sequencing (Roche 454 Life Sciences, Branford, CT, USA)

Influence of music on empirical brain networks

We analyze the influence of music in a network of FitzHugh-Nagumo oscillators with empirical structural connectivity measured in healthy human subjects. We report an increase of coherence between the global dynamics in our network and the input signal induced by a specific music song. We show that the level of coherence depends crucially on the frequency band. We compare our results with experimental data, which also describe global neural synchronization between different brain regions in the gamma-band range and its increase just before transitions between different parts of the musical form (musical high-level events). The results also suggest a split in musical form-related brain synchronization between high brain frequencies, associated with neocortical activity, and low frequencies in the range of dance movements, associated with interactivity between cortical and subcortical regions. Finally, we discuss the general modalities of the influence of music on the human brain.Comment: 24 pages, 10 figures. arXiv admin note: text overlap with arXiv:2103.1380