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Kobayashi Y.,Kyoto University | Telschow A.,Helmholtz center for infectious biology | Telschow A.,Westfalian Wilhelms University
Evolution | Year: 2011

The goal of this study is to develop a unifying theoretical framework to quantify the strength of reproductive isolation. We propose the use of the "effective recombination rate," which measures how fast associations of genes are broken by interlocus recombination. Applying the well-established theory of the effective migration rate, we derive two techniques to investigate the effective recombination rate in models of speciation: the weak migration approximation for parapatric scenarios and the weak recombination approximation for sympatric scenarios. We illustrate the use of these two methods by two examples each: (1) single-locus genetic incompatibility and (2) two-locus genetic incompatibility for the first method, and (3) assortative mating and (4) assortative mating combined with disruptive selection for the second method. An advantage of the effective recombination rate over previous approaches is that it integrates gene flow in both directions into a single index measuring the strength of isolation. This enables straightforward comparisons of speciation scenarios with the same or different geographic histories. The method also allows us to evaluate the relative contributions of F2 hybrid deficiency or linkage between multiple barriers in reproductive isolation. © 2010 The Author(s). Evolution © 2010 The Society for the Study of Evolution.

Boh B.,Maastricht University | Herholz S.C.,Montreal Neurological Institute | Lappe C.,Institute for Biomagnetism and Biosignalanalysis | Pantev C.,Institute for Biomagnetism and Biosignalanalysis | Pantev C.,Westfalian Wilhelms University
PLoS ONE | Year: 2011

In the present study we investigated the capacity of the memory store underlying the mismatch negativity (MMN) response in musicians and nonmusicians for complex tone patterns. While previous studies have focused either on the kind of information that can be encoded or on the decay of the memory trace over time, we studied capacity in terms of the length of tone sequences, i.e., the number of individual tones that can be fully encoded and maintained. By means of magnetoencephalography (MEG) we recorded MMN responses to deviant tones that could occur at any position of standard tone patterns composed of four, six or eight tones during passive, distracted listening. Whereas there was a reliable MMN response to deviant tones in the four-tone pattern in both musicians and nonmusicians, only some individuals showed MMN responses to the longer patterns. This finding of a reliable capacity of the short-term auditory store underlying the MMN response is in line with estimates of a three to five item capacity of the short-term memory trace from behavioural studies, although pitch and contour complexity covaried with sequence length, which might have led to an understatement of the reported capacity. Whereas there was a tendency for an enhancement of the pattern MMN in musicians compared to nonmusicians, a strong advantage for musicians could be shown in an accompanying behavioural task of detecting the deviants while attending to the stimuli for all pattern lengths, indicating that long-term musical training differentially affects the memory capacity of auditory short-term memory for complex tone patterns with and without attention. Also, a left-hemispheric lateralization of MMN responses in the six-tone pattern suggests that additional networks that help structuring the patterns in the temporal domain might be recruited for demanding auditory processing in the pitch domain. © 2011 Boh et al.

Heinick A.,Westfalian Wilhelms University | Urban K.,Westfalian Wilhelms University | Roth S.,Westfalian Wilhelms University | Spies D.,Westfalian Wilhelms University | And 4 more authors.
FASEB Journal | Year: 2010

Physiological polyamines are required in various biological processes. In the current study, we used norspermidine, a structural analog of the natural polyamine spermidine, to investigate polyamine uptake in the model organism Caenorhabditis elegans. Norspermidine was found to have two remarkable effects: it is toxic for the nematode, without affecting its food, Escherichia coli; and it hampers RNA interference. By characterizing a norspermidine-resistant C. elegans mutant strain that has been isolated in a genetic screen, we demonstrate that both effects, as well as the uptake of a fluorescent polyamine-conjugate, depend on the transporter protein CATP-5, a novel P5B-type ATPase. To our knowledge, CATP-5 represents the first P5-type ATPase that is associated with the plasma membrane, being expressed in the apical membrane of intestinal cells and the excretory cell. Moreover, genetic interaction studies using C. elegans polyamine synthesis mutants indicate that CATP-5 has a function redundant to polyamine synthesis and link reduced polyamine levels to retarded postembryonic development, reduced brood size, shortened life span, and small body size. We suggest that CATP-5 represents a crucial component of the pharmacologically important polyamine transport system, the molecular nature of which has not been identified so far in metazoa. © FASEB.

Wilhelm M.,Cooperative Osteosarcoma Study Group COSS | Dirksen U.,Westfalian Wilhelms University | Bielack S.S.,Cooperative Osteosarcoma Study Group COSS | Whelan J.S.,University College London | And 6 more authors.
Annals of Oncology | Year: 2014

Teenagers and young adults (TYA) cancer contributes substantially to morbidity and mortality in a population with much to offer society. TYA place distinct challenges upon cancer care services, many reporting feeling marginalized and their needs not being met in adult or paediatric cancer services. Bone tumours such as osteosarcoma and Ewing sarcoma, because of their age at presentation and the complexity of their care, are where challenges in managing (TYA) with cancer have often been most readily apparent. Bone sarcomas may be managed by paediatric or medical oncologists, and require fastidious attention to protocol. A lack of recent improvement in survival in TYA with bone tumours may be linked to a lack of specialist care, poor concordance with therapy in some situations and TYA-specific pharmacology. Participation in clinical trials, particularly of young adults, is low, hindering progress. All these requirements may be best met by a concerted effort to create collaborative care between adult and paediatric experts in bone sarcoma, working together to meet TYA patients' needs. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved.

Prinz T.,Westfalian Wilhelms University | Lasar B.,Alta4 Geoinformatik AG | Kruger K.P.,Westfalian Wilhelms University
Geoarchaeology | Year: 2010

The detection, surveying, and analysis of ancient settlement structures using remote sensing techniques offer a unique opportunity to quickly map the locations of archaeological objects in a relatively short time. High-resolution images contribute information to the documentation and spatial relation of these objects, especially if Geographic Information Systems (GIS) and Web-based applications are used. The aim of this study was to assess the potential use of satellite data and aerial images acquired by a remote-controlled balloon to generate geospatial data with a range of resolutions and information depths. The study area was Doliche, in the landscape of ancient Commagene (Turkey), where conventional flight campaigns are impossible or strongly restricted. Recently generated data sets (i.e., topographic maps, orthoimages, terrain models) were combined with field observations to derive ancient and modern landscape patterns and their possible relation to an assumed "ancient procession road" between the village Doliche (Dülük) and the nearby sanctuary of the Roman divinity Iupiter Dolichenus. © 2010 Wiley Periodicals, Inc.

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