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

Interplay of synchronization and cortical input in models of brain networks

It is well known that synchronization patterns and coherence have a major role in the functioning of brain networks, both in pathological and in healthy states. In particular, in the perception of sound, one can observe an increase in coherence between the global dynamics in the network and the auditory input. In this perspective article, we show that synchronization scenarios are determined by a fine interplay between network topology, the location of the input, and frequencies of these cortical input signals. To this end, we analyze the influence of an external stimulation in a network of FitzHugh-Nagumo oscillators with empirically measured structural connectivity, and discuss different areas of cortical stimulation, including the auditory cortex.Comment: 7 pages, 5 figures. arXiv admin note: text overlap with arXiv:2204.00562, arXiv:2103.1380

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

Bogato zdobione cynowe przedmioty z Wrocławia wyrazem przeobrażeń kulturowych w XIII wieku

Medieval badges, decorated spoon bowls and parts of diadems are rare archaeological finds. They are characterized by ornamentation filled with ideological content, which relates to different aspects of medieval culture – from courtly love to the heraldic aspects. Analysis of this material provides a lot of valuable information not only about medieval iconography. Pictures shown on badges and spoons indicates that cultural motives were becoming more common among medieval society. A small collection of Wrocław leadwares seems to confirm the cultural influences in Silesia from the area of Western Europe. It also points out that the number of audience of those cultural innovations is not limited only to the class that certainly had already some contact with it – knights, but also to the middle class – whether it happens because of arrival of many immigrants or of a direct contacts.Bogato zdobione cynowe przedmioty są rzadkimi znaleziskami. Charakteryzuje je ornamentyka nacechowana treściami ideowymi, które nawiązują do różnych aspektów średniowiecznej kultury – od miłości po heraldykę

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