Thomas Wilke - Academia.edu (original) (raw)

Papers by Thomas Wilke

Research paper thumbnail of Initiale therapeutische Antikoagulation nach einem venösen thromboembolischen Ereignis von Patienten mit schwerer Nierenfunktionseinschränkung

Hintergrund: Für Patienten mit schwerer Nierenfunktionseinschränkung, die nach einem venösen thro... more Hintergrund: Für Patienten mit schwerer Nierenfunktionseinschränkung, die nach einem venösen thromboembolischen Ereignis (VTE) therapeutisch antikoaguliert werden, besteht ein erhöhtes Risiko der Akkumulation der Antikoagulantien, die mit einem erhöhten Blutungsrisiko verbunden[for full text, please go to the a.m. URL]

Research paper thumbnail of Erhaia (Gastropoda: Rissooidea): phylogenetic relationships and the question of Paragonimus coevolution in Asia

The American Journal of Tropical Medicine and Hygiene, 2000

The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoi... more The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoidea and Rissooidea. The question whether or not Paragonimus shows the same specificity of host-parasite coevolved relationship as the human blood fluke Schistosoma was inspired by the finding of two sympatric snail species as hosts for Paragonimus skrjabini in Fujian Province, China: Gammatricula and Erhaia. The former species can clearly be classified as Pomatiopsidae: Triculinae. The latter has previously been classified as Pomatiopsidae: Pomatiopsinae. However, this classification based on anatomical characteristics is uncertain. In order to obtain a robust phylogenetic hypothesis for Erhaia, we have studied three gene fragments from this taxon as well as from twelve related taxa. The data show that the species involved represent four families: Pomatiopsidae, Hydrobiidae, Cochliopidae (here raised to family status), and Amnicolidae. Erhaia fits securely into the Amnicolidae. This indicates that P. skrjabini has not coevolved with snail lineages. However, P. skrjabini has so far only been reported from rissooidean snails, whereas members of the Paragonimus westermani complex have only been found in ceritheoidean snails. The implication is that there is a host specificity on the superfamily level. However, Asian freshwater species of the Ceritheoidea and Rissooidea usually are not sympatric and often prefer different habitats. It is therefore possible that ecological niche partitioning plays the primary role for Paragonimus evolution.

Research paper thumbnail of Genetic Evidence of Contemporary Dispersal of the Intermediate Snail Host of Schistosoma japonicum: Movement of an NTD Host Is Facilitated by Land Use and Landscape Connectivity

PLoS neglected tropical diseases, 2016

While the dispersal of hosts and vectors-through active or passive movement-is known to facilitat... more While the dispersal of hosts and vectors-through active or passive movement-is known to facilitate the spread and re-emergence of certain infectious diseases, little is known about the movement ecology of Oncomelania spp., intermediate snail host of the parasite Schistosoma japonicum, and its consequences for the spread of schistosomiasis in East and Southeast Asia. In China, despite intense control programs aimed at preventing schistosomiasis transmission, there is evidence in recent years of re-emergence and persistence of infection in some areas, as well as an increase in the spatial extent of the snail host. A quantitative understanding of the dispersal characteristics of the intermediate host can provide new insights into the spatial dynamics of transmission, and can assist public health officials in limiting the geographic spread of infection. Oncomelania hupensis robertsoni snails (n = 833) were sampled from 29 sites in Sichuan, China, genotyped, and analyzed using Bayesian a...

Research paper thumbnail of A Simulation-Based Treatment of Authenticated Message Exchange

Lecture Notes in Computer Science, 2009

Simulation-based security notions for cryptographic protocols are regarded as highly desirable, p... more Simulation-based security notions for cryptographic protocols are regarded as highly desirable, primarily because they admit strong composability and, consequently, a modular design. In this paper, we give a simulation-based security definition for two-round authenticated message exchange and show that a concrete protocol, 2AMEX-1, satisfies our security property, that is, we provide an ideal functionality for tworound authenticated message exchange and show that 2AMEX-1 realizes it securely. To model the involved public-key infrastructure adequately, we use a joint-state approach.

Research paper thumbnail of Oral anticoagulation use by patients with atrial fibrillation in Germany

Thrombosis and Haemostasis, 2012

SummaryAtrial fibrillation (AF) is the most common significant cardiac rhythm disorder. Oral anti... more SummaryAtrial fibrillation (AF) is the most common significant cardiac rhythm disorder. Oral anticoagulation (OAC) is recommended by guidelines in the presence of a moderate to high risk of stroke. Based on an analysis of claims-based data, the aim of this contribution is to quantify the stroke-risk dependent OAC utilisation profile of German AF patients as well as the possible causes and the associated clinical outcomes of OAC under-use. Our data set was derived from two large mandatory German medical insurance funds. Risk stratification of patients was based on the CHADS2-score and the CHA2DS2-VASc-score. Two different scenarios were constructed to deal with factors potentially disfavouring OAC use. Causes of OAC under-use and its clinical consequences were analysed using multivariate analysis. Observation year was 2008. A total of 183,448 AF patients met the inclusion criteria. This represents an AF prevalence of 2.21%. The average CHADS2-score was 2.8 (CHA2DS2-VASc-score: 4.3). ...

Research paper thumbnail of Spatially Explicit Modeling of Schistosomiasis Risk in Eastern China Based on a Synthesis of Epidemiological, Environmental and Intermediate Host Genetic Data

PLoS Neglected Tropical Diseases, 2013

Schistosomiasis japonica is a major parasitic disease threatening millions of people in China. Th... more Schistosomiasis japonica is a major parasitic disease threatening millions of people in China. Though overall prevalence was greatly reduced during the second half of the past century, continued persistence in some areas and cases of re-emergence in others remain major concerns. As many regions in China are approaching disease elimination, obtaining quantitative data on Schistosoma japonicum parasites is increasingly difficult. This study examines the distribution of schistosomiasis in eastern China, taking advantage of the fact that the single intermediate host serves as a major transmission bottleneck. Epidemiological, population-genetic and high-resolution ecological data are combined to construct a predictive model capable of estimating the probability that schistosomiasis occurs in a target area (''spatially explicit schistosomiasis risk''). Results show that intermediate host genetic parameters are correlated with the distribution of endemic disease areas, and that five explanatory variables-altitude, minimum temperature, annual precipitation, genetic distance, and haplotype diversity-discriminate between endemic and non-endemic zones. Model predictions are correlated with human infection rates observed at the county level. Visualization of the model indicates that the highest risks of disease occur in the Dongting and Poyang lake regions, as expected, as well as in some floodplain areas of the Yangtze River. High risk areas are interconnected, suggesting the complex hydrological interplay of Dongting and Poyang lakes with the Yangtze River may be important for maintaining schistosomiasis in eastern China. Results demonstrate the value of genetic parameters for risk modeling, and particularly for reducing model prediction error. The findings have important consequences both for understanding the determinants of the current distribution of S. japonicum infections, and for designing future schistosomiasis surveillance and control strategies. The results also highlight how genetic information on taxa that constitute bottlenecks to disease transmission can be of value for risk modeling.

Research paper thumbnail of Stirred, not shaken: genetic structure of the intermediate snail host Oncomelania hupensis robertsoni in an historically endemic schistosomiasis area

Parasites & Vectors, 2011

Background Oncomelania hupensis robertsoni is the sole intermediate host for Schistosoma japonicu... more Background Oncomelania hupensis robertsoni is the sole intermediate host for Schistosoma japonicum in western China. Given the close co-evolutionary relationships between snail host and parasite, there is interest in understanding the distribution of distinct snail phylogroups as well as regional population structures. Therefore, this study focuses on these aspects in a re-emergent schistosomiasis area known to harbour representatives of two phylogroups - the Deyang-Mianyang area in Sichuan Province, China. Based on a combination of mitochondrial and nuclear DNA, the following questions were addressed: 1) the phylogeography of the two O. h. robertsoni phylogroups, 2) regional and local population structure in space and time, and 3) patterns of local dispersal under different isolation-by-distance scenarios. Results The phylogenetic analyses confirmed the existence of two distinct phylogroups within O. h. robertsoni. In the study area, phylogroups appear to be separated by a mountain...

Research paper thumbnail of Rapid evolution of an ancient lake species flock: Freshwater limpets (Gastropoda: Ancylidae) in the Balkan Lake Ohrid

Organisms Diversity & Evolution, 2006

Ancient lakes have long been recognized as evolutionary theatres and hot spots of endemism; the e... more Ancient lakes have long been recognized as evolutionary theatres and hot spots of endemism; the evolution of their morphologically often highly diverse species flocks has received much attention. However, as each ancient lake has its own geological and evolutionary history, modes of speciation may differ from system to system. Ancient lakes can act as evolutionary reservoirs that assure the survival of relict species, but at the same time extant species may evolve through intralacustrine speciation. Other aspects of interest are the actual rates of immigration, diversification or extinction as well as the temporal framework of morphological change. Many of these questions have been addressed in the African (e.g. Lake Tanganyika) and Asian (e.g. Lake Baikal) ancient lakes. For an European ancient lakes (e.g. Lakes Ohrid and Prespa), such studies are largely missing. In the present paper, extraordinarily shaped endemic freshwater limpets of the genus Ancylus from the Balkan Lake Ohrid are used in a phylogeographic and phylogenetic context to test whether they represent an ancient lake species flock, to study the mode of speciation, and to assess the timing of morphological change. Based on DNA data from two mitochondrial genes (COI, LSU rDNA), it has been found that the Lake Ohrid Ancylus species form an endemic monophyletic group. In addition, the lake's feeder springs are inhabited by another, undescribed Ancylus species. All other studied waterbodies within the watershed do not support their own Ancylus lineages but are inhabited by a widespread Mediterranean taxon. The split between the species endemic to the lake and its sister taxon is dated to 1.470.6 million years ago. The study presents the first genetic confirmation for the existence of a species flock in a European ancient lake. Contrary to the prevailing opinion it shows that, concerning Ancylus, Lake Ohrid represents a site of intralacustrine speciation rather than an evolutionary reservoir. Moreover, it provides the first evidence for rapid morphological change in an European ancient lake species flock.

Research paper thumbnail of Mollusc Biodiversity and Endemism in the Potential Ancient Lake Trichonis, Greece

Malacologia, 2009

... Griffith, HI, JM Reed, MJ Leng, S. Ryan & S. Petkovski, 2002, The recent ... more ... Griffith, HI, JM Reed, MJ Leng, S. Ryan & S. Petkovski, 2002, The recent palaeoecology and conservation status of Balkan lake Dojran. ... Koussouris, TS & M. Pugh-Thomas, 1982, Macrozoobenthic studies in Lake Trichonis — western Greece. Thalassographica, 5: 17–25. ...

Research paper thumbnail of Testing biogeographical hypotheses in space and time: faunal relationships of the putative ancient Lake Eg?irdir in Asia Minor

Journal of Biogeography, 2007

Aim The aims of this study are to establish a multi-locus phylogeny-based hypothesis for the biog... more Aim The aims of this study are to establish a multi-locus phylogeny-based hypothesis for the biogeographical relationship of gastropods from the putative ancient Lake Eǧirdir, to test the respective null hypothesis, to estimate the timing of biogeographical events based on independent molecular clock approaches, and to interpret the data with respect to the putative ancient character of Lake Eǧirdir. Location Lake Eǧirdir, western Taurus Lake District, Turkey. Methods DNA sequences from the putatively only extant endemic taxon of Lake Eǧirdir, Falsipyrgula pfeiferi, as well as representatives of other pyrgulinid genera from Europe and western Asia are used for phylogenetic analyses based on Bayesian inference. The respective null hypothesis is tested utilizing parametric bootstrapping. The timing of evolutionary events is estimated based on two independent molecular clock approaches, which involve the modelling of judicious errors associated with branch-length calculations and calibration points. Results Bayesian inference indicates a very close relationship between the Lake Eǧirdir and Ponto-Caspian taxa. Parametric bootstrapping rejects the null hypothesis that these taxa are not monophyletic (P £ 0.01). The alternative hypothesis, namely monophyly of the Ponto-Caspian and Eǧirdir taxa, can therefore be accepted. The two independent molecular clock approaches show diversion times for the Ponto-Caspian/Eǧirdir taxa of 0.42 ± 0.18 and 0.43 ± 0.63 Ma. Main conclusions The present study shows that there is no close biogeographical affiliation between the probably only remaining endemic taxon of Lake Eǧirdir and taxa from central Europe or the Balkan region. Instead, there is a very close and relatively young (i.e. late Pleistocene) biogeographical relationship with the Ponto-Caspian pyrgulinids. However, fossil and comparative data from other invertebrates indicate that biogeographical connections between Lake Eǧirdir and the Ponto-Caspian region existed during various time periods, i.e. the Miocene/Pliocene, early Pleistocene, and late Pleistocene. Acknowledging the stillrestricted knowledge of the evolutionary history of the lake, the data presented here do not reject the putative ancient status of Lake Eǧirdir. Future studies utilizing endemic taxa of other lakes in the region need to show whether the western Taurus Lake District represents a melting pot of Pleistocene refuge biodiversity from different regions, and whether the admixture of divergent lineages has created a genetically distinct set of taxa that would warrant the designation of the area as a unique biogeographical subregion.

Research paper thumbnail of Testing two contrasting evolutionary patterns in ancient lakes: species flock versus species scatter in valvatid gastropods of Lake Ohrid

Research paper thumbnail of Concurrent evolution of ancient sister lakes and sister species: the freshwater gastropod genus Radix in lakes Ohrid and Prespa

Hydrobiologia, 2008

Ancient sister lakes are considered to be ancient lakes lying in close geographic proximity, shar... more Ancient sister lakes are considered to be ancient lakes lying in close geographic proximity, sharing a related origin and significant time of coexistence, usually having hydrological connection as well as a balanced degree of faunal overlap and distinctness. A paradigm for studying sister lake relationships are the ancient lakes Ohrid and Prespa in the Balkans, which are characterized by high degrees of endemicity. Three general patterns of endemic species can be distinguished for these lakes: (1) taxa that are endemic to either lake, with no close relatives in the respective sister lake, (2) closely related but distinct endemic taxa in both lakes (sister species) and (3) shared endemic taxa occurring in both lakes. In the present paper, two endemic freshwater pulmonate gastropod species, Radix relicta (Lake Ohrid) and R. pinteri (Lake Prespa), are used to study the evolution of presumed sister species based on biogeographical and comparative DNA data from worldwide Radix taxa. Phylogenetic, phylogeographical and parametric bootstrap analyses all suggest a sister group relationship of R. relicta and R. pinteri (pattern 2 of endemic diversity). Sister to these two taxa is the widespread R. ampla, which does not occur in the vicinity of lakes Ohrid and Prespa. The southern feeder spring complexes of Lake Ohrid are inhabited by another lineage (Radix sp. 1), which resembles Radix relicta in morphology/anatomy. For Lake Prespa, the widespread R. auricularia was reported in addition to the endemic R. pinteri. Comparative phylogenetic data favour a western Adriatic zoogeographical affinity of lakes Ohrid and Prespa over an Aegean-Anatolian faunal connection. The status of lakes Ohrid and Prespa as sister lakes is evaluated in the light of current knowledge on gastropod speciation and endemism in these hotspots of biodiversity.

Research paper thumbnail of Ancient Lake Ohrid: biodiversity and evolution

Hydrobiologia, 2008

y came into existence. These data also indicate that there is relatively little faunal exchange a... more y came into existence. These data also indicate that there is relatively little faunal exchange and overlap between Lake Ohrid and its sister lake, Lake Prespa, despite the fact that the latter lake is a major water supplier for Lake Ohrid. Studies on selected species flocks and scatters, mostly in molluscs, point towards the assumption that only few lineages originally colonized Lake Ohrid from the Balkans and that the majority of endemic species seen today probably started to evolve within the lake during the early Pleistocene. Within the Ohrid watershed, endemism occurs at different spatial and taxonomic scales, ranging from species endemic to certain parts of Lake Ohrid to species endemic to the whole watershed and from subspecies to genus level and possibly beyond. Modes of speciation in the Ohrid watershed are largely affected by its degree of isolation. Observational evidence points towards both allopatric (peripatric) and parapatric speciation. Though sympatric speciation within a habitat is conceivable, so far there are no known examples. Today, the lake suffers from increasing anthropogenic pressure and a ''creeping biodiversity crisis''. Some endemic species presumably have already gone extinct, and there are also indications of invasive species penetrating Lake Ohrid. The comparatively small size of Lake Ohrid and the extremely small range of many endemic species, together with increasing human pressure make its fauna particularly vulnerable. It is thus hoped that this review will encourage future research on the ecology and evolutionary biology of the lake's taxa, the knowledge of which would ultimately help protecting this unique European biodiversity hot spot.

Research paper thumbnail of Infraspecific mitochondrial sequence diversity in Hydrobia ulvae and Hydrobia ventrosa (Hydrobiidae: Rissooidea: Gastropoda): Do their different life histories affect biogeographic patterns and gene flow?

Biological Journal of the Linnean Society, 2000

Infraspecific relationships and population parameters are largely unknown in the ecologically sig... more Infraspecific relationships and population parameters are largely unknown in the ecologically significant mud snail genus H j d r o b i a s./. We therefore studied inftaspecific variation, population structure and gene flow in two Hq'dTobia species with different life history strategies: the marine, planktonic H. uhae and the brackish-\vater, directly developing H. uenfrosa. Based on sequencing data of a 638bp fracgn7ent of the mtDNA gene for cytochrome oxidase I, we found considerable differences between the tw.0 species. H. ulznr shows high ai'erage painvise nucleotide diversity, low population level differentiation (F\,-), and high average gene flow (Nm) between populations. Dispersal appears to accord with M'right's island model. In contrast, many populations of H. ventrosa have high population level differentiation and low gene flow. The average painvise nucleotide diversity is relatively low; this species disperses according to \\'right's isolation by distance model. Differences in dispersal modes and gene flow could be partly due to differences in type of early ontogeny and quantitative differences in passive dispersal. However, the fact that H. ulziae is a marine species with high tolerance to environmental stress and therefore less sensitive to migration barriers than H. wntrosa may better explain these dflerences. The extant lineages of H. ulziae and H. r~entrosa most likely evolved in the northeastern Atlantic during the Pleistocene. 0 2000 'rhr Linnean Snciet) of Loiidoii ADDITIONAL KE\71'0RDS:-mtDNA cytochrome oxidase I ~ population geneticsevolutionary biology ~ dispersal ~ Fs7 ~ Nn.

Research paper thumbnail of Dynamic Noninterference: Consistent Policies, Characterizations and Verification

We develop a theory for state-based noninterference in a setting where different security policie... more We develop a theory for state-based noninterference in a setting where different security policies-we call them local policies-apply in different parts of a given system. Our theory comprises appropriate security definitions, characterizations of these definitions, for instance in terms of unwindings, algorithms for analyzing the security of systems with local policies, and corresponding complexity results.

Research paper thumbnail of Oncomelania hupensis (Gastropoda: Rissooidea) in eastern China: molecular phylogeny, population structure, and ecology

Acta Tropica, 2000

The rissooidean snail genus Oncomelania is of medical interest as various taxa are hosts for the ... more The rissooidean snail genus Oncomelania is of medical interest as various taxa are hosts for the human blood fluke Schistosoma and the lung fluke Paragonimus; because of close co-evolved host-parasite-relationships, snail diversity may reflect parasite diversity. There is a considerable amount of confusion regarding the identity of smooth-and ribbed-shelled populations of Oncomelania hupensis in eastern China. We therefore studied the genetic variation, population structure, phylogenetic relationships and ecology of five smooth-and five ribbed-shelled populations in Hubei, Hunan, Anhui, Zhejiang, and Jiangsu provinces. Based on sequencing data of a fragment of the mitochondrial gene for cytochrome oxidase I from 80 individuals, we found little genetic variability within the ingroup-individuals studied here (average y =0.01922). Moreover, within the ingroup, smooth-shelled individuals cluster together with ribbed-shelled individuals. We therefore consider all smooth-and ribbed-shelled populations of Oncomelania throughout the lower Yangtze River basin to belong to the subspecies O. hupensis hupensis. Our data indicate that ribbing in O. h. hupensis is associated with the annual floods of the Yangtze River. The greatest haplotype (d H) and nucleotide diversities (y) are found in aggregates of ribbed-shelled snails along areas of the Yangtze River drainage subject to flooding. In areas not affected by flooding, the shells are smooth and genetic diversity decreases significantly.

Research paper thumbnail of Implications of mitochondrial DNA polyphyly in two ecologically undifferentiated but morphologically distinct migratory birds, the masked and white-browed woodswallows Artamus spp. of inland Australia

Journal of Avian Biology, 2006

The white-browed woodswallow Artamus superciliosus and masked woodswallow A. personatus (Passerif... more The white-browed woodswallow Artamus superciliosus and masked woodswallow A. personatus (Passeriformes: Artamidae) are members of Australia's diverse arid-and semi-arid zone avifauna. Widely sympatric and among Australia's relatively few obligate long-distance ...

Research paper thumbnail of Initiale therapeutische Antikoagulation nach einem venösen thromboembolischen Ereignis von Patienten mit schwerer Nierenfunktionseinschränkung

Hintergrund: Für Patienten mit schwerer Nierenfunktionseinschränkung, die nach einem venösen thro... more Hintergrund: Für Patienten mit schwerer Nierenfunktionseinschränkung, die nach einem venösen thromboembolischen Ereignis (VTE) therapeutisch antikoaguliert werden, besteht ein erhöhtes Risiko der Akkumulation der Antikoagulantien, die mit einem erhöhten Blutungsrisiko verbunden[for full text, please go to the a.m. URL]

Research paper thumbnail of Erhaia (Gastropoda: Rissooidea): phylogenetic relationships and the question of Paragonimus coevolution in Asia

The American Journal of Tropical Medicine and Hygiene, 2000

The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoi... more The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoidea and Rissooidea. The question whether or not Paragonimus shows the same specificity of host-parasite coevolved relationship as the human blood fluke Schistosoma was inspired by the finding of two sympatric snail species as hosts for Paragonimus skrjabini in Fujian Province, China: Gammatricula and Erhaia. The former species can clearly be classified as Pomatiopsidae: Triculinae. The latter has previously been classified as Pomatiopsidae: Pomatiopsinae. However, this classification based on anatomical characteristics is uncertain. In order to obtain a robust phylogenetic hypothesis for Erhaia, we have studied three gene fragments from this taxon as well as from twelve related taxa. The data show that the species involved represent four families: Pomatiopsidae, Hydrobiidae, Cochliopidae (here raised to family status), and Amnicolidae. Erhaia fits securely into the Amnicolidae. This indicates that P. skrjabini has not coevolved with snail lineages. However, P. skrjabini has so far only been reported from rissooidean snails, whereas members of the Paragonimus westermani complex have only been found in ceritheoidean snails. The implication is that there is a host specificity on the superfamily level. However, Asian freshwater species of the Ceritheoidea and Rissooidea usually are not sympatric and often prefer different habitats. It is therefore possible that ecological niche partitioning plays the primary role for Paragonimus evolution.

Research paper thumbnail of Genetic Evidence of Contemporary Dispersal of the Intermediate Snail Host of Schistosoma japonicum: Movement of an NTD Host Is Facilitated by Land Use and Landscape Connectivity

PLoS neglected tropical diseases, 2016

While the dispersal of hosts and vectors-through active or passive movement-is known to facilitat... more While the dispersal of hosts and vectors-through active or passive movement-is known to facilitate the spread and re-emergence of certain infectious diseases, little is known about the movement ecology of Oncomelania spp., intermediate snail host of the parasite Schistosoma japonicum, and its consequences for the spread of schistosomiasis in East and Southeast Asia. In China, despite intense control programs aimed at preventing schistosomiasis transmission, there is evidence in recent years of re-emergence and persistence of infection in some areas, as well as an increase in the spatial extent of the snail host. A quantitative understanding of the dispersal characteristics of the intermediate host can provide new insights into the spatial dynamics of transmission, and can assist public health officials in limiting the geographic spread of infection. Oncomelania hupensis robertsoni snails (n = 833) were sampled from 29 sites in Sichuan, China, genotyped, and analyzed using Bayesian a...

Research paper thumbnail of A Simulation-Based Treatment of Authenticated Message Exchange

Lecture Notes in Computer Science, 2009

Simulation-based security notions for cryptographic protocols are regarded as highly desirable, p... more Simulation-based security notions for cryptographic protocols are regarded as highly desirable, primarily because they admit strong composability and, consequently, a modular design. In this paper, we give a simulation-based security definition for two-round authenticated message exchange and show that a concrete protocol, 2AMEX-1, satisfies our security property, that is, we provide an ideal functionality for tworound authenticated message exchange and show that 2AMEX-1 realizes it securely. To model the involved public-key infrastructure adequately, we use a joint-state approach.

Research paper thumbnail of Oral anticoagulation use by patients with atrial fibrillation in Germany

Thrombosis and Haemostasis, 2012

SummaryAtrial fibrillation (AF) is the most common significant cardiac rhythm disorder. Oral anti... more SummaryAtrial fibrillation (AF) is the most common significant cardiac rhythm disorder. Oral anticoagulation (OAC) is recommended by guidelines in the presence of a moderate to high risk of stroke. Based on an analysis of claims-based data, the aim of this contribution is to quantify the stroke-risk dependent OAC utilisation profile of German AF patients as well as the possible causes and the associated clinical outcomes of OAC under-use. Our data set was derived from two large mandatory German medical insurance funds. Risk stratification of patients was based on the CHADS2-score and the CHA2DS2-VASc-score. Two different scenarios were constructed to deal with factors potentially disfavouring OAC use. Causes of OAC under-use and its clinical consequences were analysed using multivariate analysis. Observation year was 2008. A total of 183,448 AF patients met the inclusion criteria. This represents an AF prevalence of 2.21%. The average CHADS2-score was 2.8 (CHA2DS2-VASc-score: 4.3). ...

Research paper thumbnail of Spatially Explicit Modeling of Schistosomiasis Risk in Eastern China Based on a Synthesis of Epidemiological, Environmental and Intermediate Host Genetic Data

PLoS Neglected Tropical Diseases, 2013

Schistosomiasis japonica is a major parasitic disease threatening millions of people in China. Th... more Schistosomiasis japonica is a major parasitic disease threatening millions of people in China. Though overall prevalence was greatly reduced during the second half of the past century, continued persistence in some areas and cases of re-emergence in others remain major concerns. As many regions in China are approaching disease elimination, obtaining quantitative data on Schistosoma japonicum parasites is increasingly difficult. This study examines the distribution of schistosomiasis in eastern China, taking advantage of the fact that the single intermediate host serves as a major transmission bottleneck. Epidemiological, population-genetic and high-resolution ecological data are combined to construct a predictive model capable of estimating the probability that schistosomiasis occurs in a target area (''spatially explicit schistosomiasis risk''). Results show that intermediate host genetic parameters are correlated with the distribution of endemic disease areas, and that five explanatory variables-altitude, minimum temperature, annual precipitation, genetic distance, and haplotype diversity-discriminate between endemic and non-endemic zones. Model predictions are correlated with human infection rates observed at the county level. Visualization of the model indicates that the highest risks of disease occur in the Dongting and Poyang lake regions, as expected, as well as in some floodplain areas of the Yangtze River. High risk areas are interconnected, suggesting the complex hydrological interplay of Dongting and Poyang lakes with the Yangtze River may be important for maintaining schistosomiasis in eastern China. Results demonstrate the value of genetic parameters for risk modeling, and particularly for reducing model prediction error. The findings have important consequences both for understanding the determinants of the current distribution of S. japonicum infections, and for designing future schistosomiasis surveillance and control strategies. The results also highlight how genetic information on taxa that constitute bottlenecks to disease transmission can be of value for risk modeling.

Research paper thumbnail of Stirred, not shaken: genetic structure of the intermediate snail host Oncomelania hupensis robertsoni in an historically endemic schistosomiasis area

Parasites & Vectors, 2011

Background Oncomelania hupensis robertsoni is the sole intermediate host for Schistosoma japonicu... more Background Oncomelania hupensis robertsoni is the sole intermediate host for Schistosoma japonicum in western China. Given the close co-evolutionary relationships between snail host and parasite, there is interest in understanding the distribution of distinct snail phylogroups as well as regional population structures. Therefore, this study focuses on these aspects in a re-emergent schistosomiasis area known to harbour representatives of two phylogroups - the Deyang-Mianyang area in Sichuan Province, China. Based on a combination of mitochondrial and nuclear DNA, the following questions were addressed: 1) the phylogeography of the two O. h. robertsoni phylogroups, 2) regional and local population structure in space and time, and 3) patterns of local dispersal under different isolation-by-distance scenarios. Results The phylogenetic analyses confirmed the existence of two distinct phylogroups within O. h. robertsoni. In the study area, phylogroups appear to be separated by a mountain...

Research paper thumbnail of Rapid evolution of an ancient lake species flock: Freshwater limpets (Gastropoda: Ancylidae) in the Balkan Lake Ohrid

Organisms Diversity & Evolution, 2006

Ancient lakes have long been recognized as evolutionary theatres and hot spots of endemism; the e... more Ancient lakes have long been recognized as evolutionary theatres and hot spots of endemism; the evolution of their morphologically often highly diverse species flocks has received much attention. However, as each ancient lake has its own geological and evolutionary history, modes of speciation may differ from system to system. Ancient lakes can act as evolutionary reservoirs that assure the survival of relict species, but at the same time extant species may evolve through intralacustrine speciation. Other aspects of interest are the actual rates of immigration, diversification or extinction as well as the temporal framework of morphological change. Many of these questions have been addressed in the African (e.g. Lake Tanganyika) and Asian (e.g. Lake Baikal) ancient lakes. For an European ancient lakes (e.g. Lakes Ohrid and Prespa), such studies are largely missing. In the present paper, extraordinarily shaped endemic freshwater limpets of the genus Ancylus from the Balkan Lake Ohrid are used in a phylogeographic and phylogenetic context to test whether they represent an ancient lake species flock, to study the mode of speciation, and to assess the timing of morphological change. Based on DNA data from two mitochondrial genes (COI, LSU rDNA), it has been found that the Lake Ohrid Ancylus species form an endemic monophyletic group. In addition, the lake's feeder springs are inhabited by another, undescribed Ancylus species. All other studied waterbodies within the watershed do not support their own Ancylus lineages but are inhabited by a widespread Mediterranean taxon. The split between the species endemic to the lake and its sister taxon is dated to 1.470.6 million years ago. The study presents the first genetic confirmation for the existence of a species flock in a European ancient lake. Contrary to the prevailing opinion it shows that, concerning Ancylus, Lake Ohrid represents a site of intralacustrine speciation rather than an evolutionary reservoir. Moreover, it provides the first evidence for rapid morphological change in an European ancient lake species flock.

Research paper thumbnail of Mollusc Biodiversity and Endemism in the Potential Ancient Lake Trichonis, Greece

Malacologia, 2009

... Griffith, HI, JM Reed, MJ Leng, S. Ryan & S. Petkovski, 2002, The recent ... more ... Griffith, HI, JM Reed, MJ Leng, S. Ryan & S. Petkovski, 2002, The recent palaeoecology and conservation status of Balkan lake Dojran. ... Koussouris, TS & M. Pugh-Thomas, 1982, Macrozoobenthic studies in Lake Trichonis — western Greece. Thalassographica, 5: 17–25. ...

Research paper thumbnail of Testing biogeographical hypotheses in space and time: faunal relationships of the putative ancient Lake Eg?irdir in Asia Minor

Journal of Biogeography, 2007

Aim The aims of this study are to establish a multi-locus phylogeny-based hypothesis for the biog... more Aim The aims of this study are to establish a multi-locus phylogeny-based hypothesis for the biogeographical relationship of gastropods from the putative ancient Lake Eǧirdir, to test the respective null hypothesis, to estimate the timing of biogeographical events based on independent molecular clock approaches, and to interpret the data with respect to the putative ancient character of Lake Eǧirdir. Location Lake Eǧirdir, western Taurus Lake District, Turkey. Methods DNA sequences from the putatively only extant endemic taxon of Lake Eǧirdir, Falsipyrgula pfeiferi, as well as representatives of other pyrgulinid genera from Europe and western Asia are used for phylogenetic analyses based on Bayesian inference. The respective null hypothesis is tested utilizing parametric bootstrapping. The timing of evolutionary events is estimated based on two independent molecular clock approaches, which involve the modelling of judicious errors associated with branch-length calculations and calibration points. Results Bayesian inference indicates a very close relationship between the Lake Eǧirdir and Ponto-Caspian taxa. Parametric bootstrapping rejects the null hypothesis that these taxa are not monophyletic (P £ 0.01). The alternative hypothesis, namely monophyly of the Ponto-Caspian and Eǧirdir taxa, can therefore be accepted. The two independent molecular clock approaches show diversion times for the Ponto-Caspian/Eǧirdir taxa of 0.42 ± 0.18 and 0.43 ± 0.63 Ma. Main conclusions The present study shows that there is no close biogeographical affiliation between the probably only remaining endemic taxon of Lake Eǧirdir and taxa from central Europe or the Balkan region. Instead, there is a very close and relatively young (i.e. late Pleistocene) biogeographical relationship with the Ponto-Caspian pyrgulinids. However, fossil and comparative data from other invertebrates indicate that biogeographical connections between Lake Eǧirdir and the Ponto-Caspian region existed during various time periods, i.e. the Miocene/Pliocene, early Pleistocene, and late Pleistocene. Acknowledging the stillrestricted knowledge of the evolutionary history of the lake, the data presented here do not reject the putative ancient status of Lake Eǧirdir. Future studies utilizing endemic taxa of other lakes in the region need to show whether the western Taurus Lake District represents a melting pot of Pleistocene refuge biodiversity from different regions, and whether the admixture of divergent lineages has created a genetically distinct set of taxa that would warrant the designation of the area as a unique biogeographical subregion.

Research paper thumbnail of Testing two contrasting evolutionary patterns in ancient lakes: species flock versus species scatter in valvatid gastropods of Lake Ohrid

Research paper thumbnail of Concurrent evolution of ancient sister lakes and sister species: the freshwater gastropod genus Radix in lakes Ohrid and Prespa

Hydrobiologia, 2008

Ancient sister lakes are considered to be ancient lakes lying in close geographic proximity, shar... more Ancient sister lakes are considered to be ancient lakes lying in close geographic proximity, sharing a related origin and significant time of coexistence, usually having hydrological connection as well as a balanced degree of faunal overlap and distinctness. A paradigm for studying sister lake relationships are the ancient lakes Ohrid and Prespa in the Balkans, which are characterized by high degrees of endemicity. Three general patterns of endemic species can be distinguished for these lakes: (1) taxa that are endemic to either lake, with no close relatives in the respective sister lake, (2) closely related but distinct endemic taxa in both lakes (sister species) and (3) shared endemic taxa occurring in both lakes. In the present paper, two endemic freshwater pulmonate gastropod species, Radix relicta (Lake Ohrid) and R. pinteri (Lake Prespa), are used to study the evolution of presumed sister species based on biogeographical and comparative DNA data from worldwide Radix taxa. Phylogenetic, phylogeographical and parametric bootstrap analyses all suggest a sister group relationship of R. relicta and R. pinteri (pattern 2 of endemic diversity). Sister to these two taxa is the widespread R. ampla, which does not occur in the vicinity of lakes Ohrid and Prespa. The southern feeder spring complexes of Lake Ohrid are inhabited by another lineage (Radix sp. 1), which resembles Radix relicta in morphology/anatomy. For Lake Prespa, the widespread R. auricularia was reported in addition to the endemic R. pinteri. Comparative phylogenetic data favour a western Adriatic zoogeographical affinity of lakes Ohrid and Prespa over an Aegean-Anatolian faunal connection. The status of lakes Ohrid and Prespa as sister lakes is evaluated in the light of current knowledge on gastropod speciation and endemism in these hotspots of biodiversity.

Research paper thumbnail of Ancient Lake Ohrid: biodiversity and evolution

Hydrobiologia, 2008

y came into existence. These data also indicate that there is relatively little faunal exchange a... more y came into existence. These data also indicate that there is relatively little faunal exchange and overlap between Lake Ohrid and its sister lake, Lake Prespa, despite the fact that the latter lake is a major water supplier for Lake Ohrid. Studies on selected species flocks and scatters, mostly in molluscs, point towards the assumption that only few lineages originally colonized Lake Ohrid from the Balkans and that the majority of endemic species seen today probably started to evolve within the lake during the early Pleistocene. Within the Ohrid watershed, endemism occurs at different spatial and taxonomic scales, ranging from species endemic to certain parts of Lake Ohrid to species endemic to the whole watershed and from subspecies to genus level and possibly beyond. Modes of speciation in the Ohrid watershed are largely affected by its degree of isolation. Observational evidence points towards both allopatric (peripatric) and parapatric speciation. Though sympatric speciation within a habitat is conceivable, so far there are no known examples. Today, the lake suffers from increasing anthropogenic pressure and a ''creeping biodiversity crisis''. Some endemic species presumably have already gone extinct, and there are also indications of invasive species penetrating Lake Ohrid. The comparatively small size of Lake Ohrid and the extremely small range of many endemic species, together with increasing human pressure make its fauna particularly vulnerable. It is thus hoped that this review will encourage future research on the ecology and evolutionary biology of the lake's taxa, the knowledge of which would ultimately help protecting this unique European biodiversity hot spot.

Research paper thumbnail of Infraspecific mitochondrial sequence diversity in Hydrobia ulvae and Hydrobia ventrosa (Hydrobiidae: Rissooidea: Gastropoda): Do their different life histories affect biogeographic patterns and gene flow?

Biological Journal of the Linnean Society, 2000

Infraspecific relationships and population parameters are largely unknown in the ecologically sig... more Infraspecific relationships and population parameters are largely unknown in the ecologically significant mud snail genus H j d r o b i a s./. We therefore studied inftaspecific variation, population structure and gene flow in two Hq'dTobia species with different life history strategies: the marine, planktonic H. uhae and the brackish-\vater, directly developing H. uenfrosa. Based on sequencing data of a 638bp fracgn7ent of the mtDNA gene for cytochrome oxidase I, we found considerable differences between the tw.0 species. H. ulznr shows high ai'erage painvise nucleotide diversity, low population level differentiation (F\,-), and high average gene flow (Nm) between populations. Dispersal appears to accord with M'right's island model. In contrast, many populations of H. ventrosa have high population level differentiation and low gene flow. The average painvise nucleotide diversity is relatively low; this species disperses according to \\'right's isolation by distance model. Differences in dispersal modes and gene flow could be partly due to differences in type of early ontogeny and quantitative differences in passive dispersal. However, the fact that H. ulziae is a marine species with high tolerance to environmental stress and therefore less sensitive to migration barriers than H. wntrosa may better explain these dflerences. The extant lineages of H. ulziae and H. r~entrosa most likely evolved in the northeastern Atlantic during the Pleistocene. 0 2000 'rhr Linnean Snciet) of Loiidoii ADDITIONAL KE\71'0RDS:-mtDNA cytochrome oxidase I ~ population geneticsevolutionary biology ~ dispersal ~ Fs7 ~ Nn.

Research paper thumbnail of Dynamic Noninterference: Consistent Policies, Characterizations and Verification

We develop a theory for state-based noninterference in a setting where different security policie... more We develop a theory for state-based noninterference in a setting where different security policies-we call them local policies-apply in different parts of a given system. Our theory comprises appropriate security definitions, characterizations of these definitions, for instance in terms of unwindings, algorithms for analyzing the security of systems with local policies, and corresponding complexity results.

Research paper thumbnail of Oncomelania hupensis (Gastropoda: Rissooidea) in eastern China: molecular phylogeny, population structure, and ecology

Acta Tropica, 2000

The rissooidean snail genus Oncomelania is of medical interest as various taxa are hosts for the ... more The rissooidean snail genus Oncomelania is of medical interest as various taxa are hosts for the human blood fluke Schistosoma and the lung fluke Paragonimus; because of close co-evolved host-parasite-relationships, snail diversity may reflect parasite diversity. There is a considerable amount of confusion regarding the identity of smooth-and ribbed-shelled populations of Oncomelania hupensis in eastern China. We therefore studied the genetic variation, population structure, phylogenetic relationships and ecology of five smooth-and five ribbed-shelled populations in Hubei, Hunan, Anhui, Zhejiang, and Jiangsu provinces. Based on sequencing data of a fragment of the mitochondrial gene for cytochrome oxidase I from 80 individuals, we found little genetic variability within the ingroup-individuals studied here (average y =0.01922). Moreover, within the ingroup, smooth-shelled individuals cluster together with ribbed-shelled individuals. We therefore consider all smooth-and ribbed-shelled populations of Oncomelania throughout the lower Yangtze River basin to belong to the subspecies O. hupensis hupensis. Our data indicate that ribbing in O. h. hupensis is associated with the annual floods of the Yangtze River. The greatest haplotype (d H) and nucleotide diversities (y) are found in aggregates of ribbed-shelled snails along areas of the Yangtze River drainage subject to flooding. In areas not affected by flooding, the shells are smooth and genetic diversity decreases significantly.

Research paper thumbnail of Implications of mitochondrial DNA polyphyly in two ecologically undifferentiated but morphologically distinct migratory birds, the masked and white-browed woodswallows Artamus spp. of inland Australia

Journal of Avian Biology, 2006

The white-browed woodswallow Artamus superciliosus and masked woodswallow A. personatus (Passerif... more The white-browed woodswallow Artamus superciliosus and masked woodswallow A. personatus (Passeriformes: Artamidae) are members of Australia's diverse arid-and semi-arid zone avifauna. Widely sympatric and among Australia's relatively few obligate long-distance ...