20,736 research outputs found

    Wave breaking of periodic solutions to the Fornberg-Whitham equation

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    Based on recent well-posedness results in Sobolev (or Besov spaces) for periodic solutions to the Fornberg-Whitham equations we investigate here the questions of wave breaking and blow-up for these solutions. We show first that finite maximal life time of a solution necessarily leads to wave breaking. Second, we prove that for a certain class of initial wave profiles the corresponding solutions do indeed blow-up in finite time

    Artificial and Natural Genetic Information Processing

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    Conventional methods of genetic engineering and more recent genome editing techniques focus on identifying genetic target sequences for manipulation. This is a result of historical concept of the gene which was also the main assumption of the ENCODE project designed to identify all functional elements in the human genome sequence. However, the theoretical core concept changed dramatically. The old concept of genetic sequences which can be assembled and manipulated like molecular bricks has problems in explaining the natural genome-editing competences of viruses and RNA consortia that are able to insert or delete, combine and recombine genetic sequences more precisely than random-like into cellular host organisms according to adaptational needs or even generate sequences de novo. Increasing knowledge about natural genome editing questions the traditional narrative of mutations (error replications) as essential for generating genetic diversity and genetic content arrangements in biological systems. This may have far-reaching consequences for our understanding of artificial genome editing

    Judge Roy\u27s Playground: A History of Astroworld

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    Telomeres in Evolution and Development from Biosemiotic Perspective

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    Telomeres identify natural chromosome ends being different from broken DNA through differences in their "molecular syntax" (M.Eigen) which determines the functions of reverse transcriptase and its integrated RNA template, telomerase. Although telomeres play a crucial role in the linear chromosome organization of eukaryotic cells, their molecular syntax descended from an ancient retroviral competence. This is an indicator for the early retroviral colonization of large double stranded DNA viruses, which are putative ancestors of the eukaryotic nucleus.
This talk will demonstrate certain advantages of the biosemiotic approach towards our evolutionary understanding of telomeres: focus on the genetic/genomic structures as language-like text which follows combinatorial (syntactic), context-sensitive (pragmatic) and
content-specific (semantic) semiotic rules. Genetic/genomic organization from the biosemiotic perspective is not seen any longer as an object of randomly derived alterations (mutations) but as functional innovation coherent with the broad variety of natural genome editing competences of viruses.
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    Biocommunication of Fungal Organisms

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    The development and growth of fungal organisms depend on successful communication processes (a) within the organism and between organisms, (b) with the same or related species and (c) with non-related organisms. In order to generate an appropriate response behaviour, fungal organisms must also be able to (d) correctly interpret meaningful information from the abiotic environment. However, these communication and interpretation processes can also fail. In such cases the overall results can induce disease-causing and even lethal consequences for the organism. 

	This review will not enrich the knowledge of specialists in fungal research, but will demonstrate to a broader readership the different levels of fungal communication and how versatile fungal communicative competences really are. Interestingly, certain rules of fungal communication are very similar to those of animals, while others resemble those of plants. The correspondence between all three eukaryotic kingdoms has two aspects: (1) the context determines the meaning of trans-, inter- and intra-organismic (inter- and intracellular) communication, while (2) differences in abiotic and biotic signal perception determine the content arrangement of response behaviour

    LHC Expectations (Machine, Detectors and Physics)

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    Starting in two years from now, particle physics will enter a new regime in terms of energies and luminosities, thanks to the Large Hadron Collider (LHC) at CERN. This report summarizes the status of the preparations, both for the machine and the detectors, as of fall 2005. The commissioning and start-up scenarios are outlined and some highlights from the very rich physics programme are given, concentrating on measurements of Standard Model processes, as well as on early discovery scenarios. The prospects of B-physics and heavy ion collisions at LHC are also briefly discussed. The report concludes with an outlook on the ultimate physics reach and on upgrade scenarios.Comment: Plenary talk given at the International Europhysics Conference on High Energy Physics, July 21st - 27th 2005, Lisboa, Portuga

    Bio-Communication of Bacteria and its Evolutionary Interrelations to Natural Genome Editing Competences of Viruses

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    Communicative competences enable bacteria to develop, organise and coordinate rich social life with a great variety of behavioral patterns even in which they organise themselves like multicellular organisms. They have existed for almost four billion years and still survive, being part of the most dramatic changes in evolutionary history such as DNA invention, cellular life, invention of nearly all protein types, partial constitution of eukaryotic cells, vertical colonisation of all eukaryotes, high adaptability through horizontal gene transfer and co-operative multispecies colonisation of all ecological niches. Recent research demonstrates that these bacterial competences derive from the aptitude of viruses for natural genome editing. 
	In contrast to a book which would be the appropriate space to outline in depth all communicative pathways inherent in bacterial life in this current article I want to give an overview for a broader readership over the great variety of bacterial bio-communication: In a first step I describe how they interpret and coordinate, what semiochemical vocabulary they share and which goals they try to reach. In a second stage I describe the main categories of sign-mediated interactions between bacterial and non-bacterial organisms, and between bacteria of the same or related species. In a third stage I will focus on the relationship between bacteria and their obligate settlers, i.e. viruses. We will see that bacteria are important hosts for multiviral colonisation and virally-determined order of nucleic acid sequences.

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