| 1. |
- Dlugosz, Aldona, et al.
(author)
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No difference in small bowel microbiota between patients with irritable bowel syndrome and healthy controls
- 2015
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Journal article (peer-reviewed)abstract
- Several studies have indicated that colonic microbiota may exhibit important differences between patients with irritable bowel syndrome (IBS) and healthy controls. Less is known about the microbiota of the small bowel. We used massive parallel sequencing to explore the composition of small bowel mucosa-associated microbiota in patients with IBS and healthy controls. We analysed capsule biopsies from the jejunum of 35 patients (26 females) with IBS aged 18-(36)-57 years and 16 healthy volunteers (11 females) aged 20-(32)-48 years. Sequences were analysed based on taxonomic classification. The phyla with the highest total abundance across all samples were: Firmicutes (43%), Proteobacteria (23%), Bacteroidetes (15%), Actinobacteria (9.3%) and Fusobacteria (7.0%). The most abundant genera were: Streptococcus (19%), Veillonella (13%), Prevotella (12%), Rothia (6.4%), Haemophilus (5.7%), Actinobacillus (5.5%), Escherichia (4.6%) and Fusobacterium (4.3%). We found no difference among major phyla or genera between patients with IBS and controls. We identified a cluster of samples in the small bowel microbiota dominated by Prevotella, which may represent a common enterotype of the upper small intestine. The remaining samples formed a gradient, dominated by Streptococcus at one end and Escherichia at the other.
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| 2. |
- Gaidashev, Denis, et al.
(author)
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Existence of a Lorenz renormalization fixed point of an arbitrary critical order
- 2012
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In: Nonlinearity. - : IOP Publishing. - 0951-7715 .- 1361-6544. ; 25:6, s. 1819-1841
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Journal article (peer-reviewed)abstract
- We present a proof of the existence of a renormalization fixed point for Lorenz maps of the simplest non-unimodal combinatorial type ({0, 1}, {1, 0, 0}) and with a critical point of arbitrary order rho > 1.
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| 3. |
- Grieser, M., et al.
(author)
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Storage ring at HIE-ISOLDE
- 2012
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In: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117
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Journal article (peer-reviewed)abstract
- We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
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| 4. |
- Martens, Marco, et al.
(author)
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On the Hyperbolicity of Lorenz Renormalization
- 2014
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In: Communications in Mathematical Physics. - : Springer Science and Business Media LLC. - 0010-3616 .- 1432-0916. ; 325:1, s. 185-257
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Journal article (peer-reviewed)abstract
- We consider infinitely renormalizable Lorenz maps with real critical exponent alpha > 1 of certain monotone combinatorial types. We prove the existence of periodic points of the renormalization operator, and that each map in the limit set of renormalization has an associated two-dimensional strong unstable manifold. For monotone families of Lorenz maps we prove that each infinitely renormalizable combinatorial type has a unique representative within the family. We also prove that each infinitely renormalizable map has no wandering intervals, is ergodic, and has a uniquely ergodic minimal Cantor attractor of measure zero.
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| 5. |
- Martens, M., et al.
(author)
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Physical measures for infinitely renormalizable Lorenz maps
- 2018
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In: Ergodic Theory and Dynamical Systems. - : Cambridge University Press. - 0143-3857 .- 1469-4417. ; 38, s. 717-738
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Journal article (peer-reviewed)abstract
- A physical measure on the attractor of a system describes the statistical behavior of typical orbits. An example occurs in unimodal dynamics: namely, all infinitely renormalizable unimodal maps have a physical measure. For Lorenz dynamics, even in the simple case of infinitely renormalizable systems, the existence of physical measures is more delicate. In this article, we construct examples of infinitely renormalizable Lorenz maps which do not have a physical measure. A priori bounds on the geometry play a crucial role in (unimodal) dynamics. There are infinitely renormalizable Lorenz maps which do not have a priori bounds. This phenomenon is related to the position of the critical point of the consecutive renormalizations. The crucial technical ingredient used to obtain these examples without a physical measure is the control of the position of these critical points.
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| 6. |
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| 7. |
- Winckler, Björn
(author)
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A renormalization fixed point for Lorenz maps
- 2010
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In: Nonlinearity. - : IOP Publishing. - 0951-7715 .- 1361-6544. ; 23:6, s. 1291-1302
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Journal article (peer-reviewed)abstract
- A Lorenz map is a Poincare map for a three-dimensional Lorenz flow. We describe the theory of renormalization for Lorenz maps with a critical point and prove that a restriction of the renormalization operator acting on such maps has a hyperbolic fixed point. The proof is computer assisted and we include a detailed exposition on how to make rigorous estimates using a computer as well as the implementation of the estimates.
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| 8. |
- Winckler, Björn
(author)
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Renormalization of Lorenz Maps
- 2011
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Doctoral thesis (other academic/artistic)abstract
- This thesis is a study of the renormalization operator on Lorenz αmaps with a critical point. Lorenz maps arise naturally as first-return maps for three-dimensional geometric Lorenz flows. Renormalization is a tool for analyzing the microscopic geometry of dynamical systems undergoing a phase transition. In the first part we develop new tools to study the limit set of renormalization for Lorenz maps whose combinatorics satisfy a long return condition. This combinatorial condition leads to the construction of a relatively compact subset of Lorenz maps which is essentially invariant under renormalization. From here we can deduce topological properties of the limit set (e.g. existence of periodic points of renormalization) as well as measure theoretic properties of infinitely renormalizable maps (e.g. existence of uniquely ergodic Cantor attractors). After this, we show how Martens’ decompositions can be used to study the differentiable structure of the limit set of renormalization. We prove that each point in the limit set has a global two-dimensional unstable manifold which is a graph and that the intersection of an unstable manifold with the domain of renormalization is a Cantor set. All results in this part are stated for arbitrary real critical exponents α> 1. In the second part we give a computer assisted proof of the existence of a hyperbolic fixed point for the renormalization operator on Lorenz maps of the simplest possible nonunimodal combinatorial type. We then show how this can be used to deduce both universality and rigidity for maps with the same combinatorial type as the fixed point. The results in this part are only stated for critical exponenta α= 2.
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