493 research outputs found
Analytical approximation for the structure of differentially rotating barotropes
Approximate analytical formula for density distribution in differentially
rotating stars is derived. Any barotropic EOS and conservative rotation law can
be handled with use of this method for wide range of differential rotation
strength. Results are in good qualitative agreement with comparison to the
other methods. Some applications are suggested and possible improvements of the
formula are discussed.Comment: 10 pages, 13 figures, accepted for publication in Monthly Notice
International Max Planck Research Schools: Neue Wege der Graduiertenausbildung
"Die IMPRS [International Max Planck Research Schools] bilden Zentren wissenschaftlicher Exzellenz auf innovativen und interdisziplinĂ€ren Forschungsgebieten, wie z.B. Neurowissenschaften oder Polymerforschung, aber auch Demografie und Bildungsforschung." Die Nachwuchsförderung findet in enger Kooperation von UniversitĂ€ten und Max-Planck-Instituten statt. Es werden PromotionsstudiengĂ€nge angeboten, "die gezielt besonders qualifizierte junge Wissenschaftlerinnen und Wissenschaftler aus dem In- und Ausland in der Phase zwischen dem ersten berufsqualifizierenden Abschluss und der Promotion anziehen sollen." Die Autorinnen geben allgemeine Informationen ĂŒber die IMPRS und gehen speziell auf die International Max Planck Research School "The Life Course: Evolutionary and Ontogenetic Dynamics" (LIFE) ein. AbschlieĂend findet eine Bewertung dieser Research School statt. (DIPF/Orig./av
Ecological genetic conflict: Genetic architecture can shift the balance between local adaptation and plasticity
This is the author accepted manuscript. The final version is available from University of Chicago Press via the DOI in this record.Genetic polymorphism can contribute to local adaptation in heterogeneous
habitats, for instance as a single locus with alleles adapted to different habitats.
Phenotypic plasticity can also contribute to trait variation across habitats,
through developmental responses to habitat-specific cues. We show that
the genetic architecture of genetically polymorphic and plasticity loci may influence
the balance between local adaptation and phenotypic plasticity. These
effects of genetic architecture are instances of ecological genetic conflict. A
reduced effective migration rate for genes tightly linked to a genetic polymorphism
provides an explanation for the effects, and they can occur both
for a single trait and for a syndrome of co-adapted traits. Using individualbased
simulations and numerical analysis, we investigate how among-habitat
genetic polymorphism and phenotypic plasticity depend on genetic architecture.
We also study the evolution of genetic architecture itself, in the form
of rates of recombination between genetically polymorphic loci and plasticity
loci. Our main result is that for plasticity genes that are unlinked to loci with
between-habitat genetic polymorphism, the slope of a reaction norm is steeper
in comparison with the slope favored by plasticity genes that are tightly linked
to genes for local adaptation.This work was supported by grants from the Carl Trygger
Foundation (CTS 15292) to OL and by a Leverhulme Trust International Network
Grant to SRXD, PH, OL, and JMM
Geometric Aspects of Ambrosetti-Prodi operators with Lipschitz nonlinearities
For Dirichlet boundary conditions on a bounded domain, what happens to the
critical set of the Ambrosetti-Prodi operator if the nonlinearity is only a
Lipschitz map? It turns out that many properties which hold in the smooth case
are preserved, despite of the fact that the operator is not even differentiable
at some points. In particular, a global Lyapunov-Schmidt decomposition of great
convenience for numerical inversion is still available
Cossack Love Song (Don\u27t Forget Me)
Contains advertisements and/or short musical examples of pieces being sold by publisher.https://digitalcommons.library.umaine.edu/mmb-vp/6792/thumbnail.jp
On the relevance of mitochondrial fusions for the accumulation of mitochondrial deletion mutants: A modelling study
The molecular mechanisms underlying the aging process are still unclear, but the clonal accumulation of mitochondrial deletion mutants is one of the prime candidates. An important question for the mitochondrial theory of aging is to discover how defective organelles might be selected at the expense of wild-type mitochondria. We propose that mitochondrial fission and fusion events are of critical importance for resolving this apparent contradiction. We show that the occurrence of fusions removes the problems associated with the idea that smaller DNA molecules accumulate because they replicate in a shorter time â the survival of the tiny (SOT) hypothesis. Furthermore, stochastic simulations of mitochondrial replication, mutation and degradation show that two important experimental findings, namely the overall low mosaic pattern of oxidative phosphorylation (OXPHOS) impaired cells in old organisms and the distribution of deletion sizes, can be reproduced and explained by this hypothesis. Finally, we make predictions that can be tested experimentally to further verify our explanation for the age-related accumulation of mitochondrial deletion mutants
Fold and thrust belts : structural style, evolution and exploration â an introduction
Peer reviewedPublisher PD
Mech Ageing Dev
Mitochondrial morphology is regulated in many cultured eukaryotic cells by fusion and fission of mitochondria. A tightly controlled balance between fission and fusion events is required to ensure normal mitochondrial and cellular functions. During ageing, mitochondria are undergoing significant changes on the functional and morphological level. The effect of ageing on fusion and fission of mitochondria and consequences of altered fission and fusion activity are still unknown although theoretical models on ageing consider the significance of these processes. Human umbilical vein endothelial cells (HUVECs) have been established as a cell culture model to follow mitochondrial activity and dysfunction during the ageing process. Mitochondria of old and postmitotic HUVECs showed distinct alterations in overall morphology and fine structure, and furthermore, loss of mitochondrial membrane potential. In parallel, a decrease of intact mitochondrial DNA (mtDNA) was observed. Fission and fusion activity of mitochondria were quantified in living cells. Mitochondria of old HUVECs showed a significant and equal decrease of both fusion and fission activity indicating that these processes are sensitive to ageing and could contribute to the accumulation of damaged mitochondria during ageing
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