503 research outputs found
Reconstructing the evolutionary history of the radiation of the land snail genus Xerocrassa on Crete based on mitochondrial sequences and AFLP markers
No full textSauer J, Hausdorf B. Reconstructing the evolutionary history of the radiation of the land snail genus Xerocrassa on Crete based on mitochondrial sequences and AFLP markers. BMC Evolutionary Biology. 2010;10(1): 299.Background: A non-adaptive radiation triggered by sexual selection resulted in ten endemic land snail species of the genus Xerocrassa on Crete. Only five of these species and a more widespread species are monophyletic in a mitochondrial gene tree. The reconstruction of the evolutionary history of such closely related species can be complicated by incomplete lineage sorting, introgression or inadequate taxonomy. To distinguish between the reasons for the nonmonophyly of several species in the mitochondrial gene tree we analysed nuclear AFLP markers. Results: Whereas six of the eleven morphologically delimited Xerocrassa species from Crete are monophyletic in the mitochondrial gene tree, nine of these species are monophyletic in the tree based on AFLP markers. Only two morphologically delimited species could not be distinguished with the multilocus data and might have diverged very recently or might represent extreme forms of a single species. The nonmonophyly of X. rhithymna with respect to X. kydonia is probably the result of incomplete lineage sorting, because there is no evidence for admixture in the AFLP data and the mitochondrial haplotype groups of these species coalesce deeply. The same is true for the main haplotype groups of X. mesostena. The nonmonophyly of X. franciscoi might be the result of mitochondrial introgression, because the coalescences of the haplotypes of this species with some X. mesostena haplotypes are shallow and there is admixture with neighbouring X. mesostena. Conclusion: The most likely causes for the nonmonophyly of species in the mitochondrial gene tree of the Xerocrassa radiation on Crete could be inferred using AFLP data by a combination of several criteria, namely the depth of the coalescences in the gene tree, the geographical distribution of shared genetic markers, and concordance with results of admixture analyses of nuclear multilocus markers. The strongly subdivided population structure increases the effective population size of land snail species and, thus, the likelihood of a long persistence of ancestral polymorphisms. Our study suggests that ancestral polymorphisms are a frequent cause for nonmonophyly of species with a strongly subdivided population structure in gene trees
Sauer (Birth, 1885-10-18)
No full text6507/Pg 31/1885/MW/Ger./Ger./Helene Moeller, Mid.Original record filed in drawer labeled 'SANDERS-SCHAD'
Continuing Fragmentation of a Widespread Species by Geographical Barriers as Initial Step in a Land Snail Radiation on Crete
No full textSauer J, Oldeland J, Hausdorf B. Continuing Fragmentation of a Widespread Species by Geographical Barriers as Initial Step in a Land Snail Radiation on Crete. PLoS ONE. 2013;8(5): e62569.The phylogeographic structure of the land snail Xerocrassa mesostena on Crete inferred from AFLP markers and mitochondrial cox1 sequences can be explained by three mechanisms: gene flow restriction, population expansion and leptokurtic dispersal. Gene flow restriction by geographic barriers caused subdivision of the gene pool into distinct clusters. Population expansion was probably facilitated by deforestation of Crete in the postglacial. Newly available areas were colonized by leptokurtic dispersal, i.e. slow active expansion resulting in isolation by distance within the clusters and occasional long distance dispersal events that resulted in departures from the isolation by distance model. Less than one percent of the AFLP markers show correlations with environmental variables. Random phylogeographic breaks in the distribution of the mitochondrial haplotype groups indicate that single locus markers, especially mitochondrial DNA, might result in a misleading picture of the phylogeographic structure of a species. Restriction of gene flow between metapopulations caused by geographical barriers can interact with sexual selection resulting in the differentiation of these metapopulations into separate species without noticeable ecological differentiation. Evidence for gene flow between parapatrically distributed evolutionary units representing different stages of the speciation process suggests that the ongoing process of fragmentation of the X. mesostena complex might be an example for parapatric speciation. The lack of ecological differentiation between these units confirms theoretical predictions that divergent selection for local adaptation is not required for rapid speciation
Introducción a la geografía histórica
No full textSauer\u27s work opens the way for the formation of environmental knowledge of our time and contribute to its development in Latin America. The article continues a series of topics in depth by the author, and concludes by reminding us that the terrifying impact of modern Western world, does not cancel the truth that human history has been remarkably pluralistic, and there are no general laws of society, but only cultural agreements.La obra de Sauer abre paso a la formación del saber ambiental de nuestro tiempo y contribuye a su desarrollo en América Latina. El artículo sigue una serie de temas profundizados por el autor, y concluye recordándonos que el aterrador impacto del moderno mundo Occidental, no cancela la verdad de que el la historia del hombre ha sido marcadamente pluralista, y que no existen leyes generales de la sociedad, sino únicamente acuerdos culturales
Impaired gastric myoelectrical reactivity in children and adolescents with obesity compared to normal-weight controls
No full textObesity often has its onset in childhood and can be accompanied by various comorbidities such as functional gastrointestinal disorders and altered gastric myoelectrical activity (GMA). This study investigates whether obesity in childhood and adolescence is already associated with altered GMA, and whether an inpatient weight loss program affects GMA. Sixty children with obesity (OBE) and 27 normal-weight children (NW) (12.9 ± 1.7 years; 51% female) were compared for their GMA at rest, after a stress test, and after a drink-to-full water load test. A continuous electrogastrogram (EGG) was recorded and analyzed with respect to gastric slow waves and tachygastric activity. OBE were examined upon admission (T1) and before discharge (T2) following an inpatient weight loss program; NW served as control group. Compared to NW, children with obesity showed flattened GMA as indicated by lower tachygastric reactivity after stress and water load test at T1. Data of OBE did not differ between T1 and T2. EGG parameters were associated neither with sex, age, and BMI nor with subjective stress and food intake. Children with obesity show impaired gastric myoelectrical reactivity in response to a stress and water load test compared to normal-weight controls, which does not change during an inpatient weight loss program
[Schauspielhaus Düsseldorf] / Nora oder: Ein Puppenheim : Mittwoch, den 1. Februar 1911 ; Schauspiel in 3 Aufzügen
No full textvon Henrik Ibsen. Deutsch von Wilhelm Lange. Regie: Gustav Lindemann. Personen: Walter Steinbeck, Helene Robert, Ella Gries, Anna Werner, Grete Sauer, Bernhard Goetzke, Josepha Stein, Arthur Ehrens, Hilde Hansen, Elsa Dalands, Carl Mülle
[Schauspielhaus Düsseldorf] / Die Journalisten : Dienstag, den 26. Juni 1906 (historischer Lustspiel-Cyklus) ; Lustspiel in 4 Akten
No full textvon Gustav Freytag. Regie: Fritz Odemar. Personen: Gustav Beaurepaire, Fanny Ritter, Elisabeth Hruby, Oskar Groteck, Otto Stoeckel, Carl Ekert, Matthias Claudius, Walter Tautz, Arthur Schetter, Alfred Kühne, Walter Schmidthäßler, Fritz Odemar, Helene Rietz, Elisabeth Sauer, Fritz Krampert, Alfred Plange, Bernhard Goetzke, Angelina Gurlitt, Albert Fischer, Paul Henckels, Heinrich Höppne
[Schauspielhaus Düsseldorf] / Elektra : Freitag, den 18. Mai 1906 ; Tragödie in einem Akt
No full text(frei nach Sophokles) von Hugo v. Hofmannsthal. Regie: Arthur Holz. Dramatis Personae: Louise Dumont, Gertrud Seeliger, Fanny Ritter, Josef Klein, Bernhard Goetzke, Albert Fischer, Francis Gernoth, Elisabeth Sauer, Alfred Plange, Paul Henckels, Otto Fischer, Else Jansen, Helene Urfus, Claire Dunkel, Stephanie Kriß, Angelina Gurlitt, Eva Marterstei
Introducción a la geografía histórica
No full textLa obra de Sauer abre paso a la formación del saber ambiental de nuestro tiempo y contribuye a su desarrollo en América Latina. El artículo sigue una serie de temas profundizados por el autor, y concluye recordándonos que el aterrador impacto del moderno mundo Occidental, no cancela la verdad de que el la historia del hombre ha sido marcadamente pluralista, y que no existen leyes generales de la sociedad, sino únicamente acuerdos culturales.L’œuvre de Sauer ouvre la voie à la formation d’un savoir environnemental de notre temps et contribue à son développement en Amérique latine. L’article poursuit une série de thèmes approfondis par l’auteur, et conclut en nous rappelant que l’épouvantable impact du monde moderne Occidental, n’annule point la vérité que l’histoire de l’homme a toujours été pluraliste, et qu’il n’existe point de lois générales de la société mais uniquement des accords culturels.Sauer's work opens the way for the formation of environmental knowledge of our time and contribute to its development in Latin America. The article continues a series of topics in depth by the author, and concludes by reminding us that the terrifying impact of modern Western world, does not cancel the truth that human history has been remarkably pluralistic, and there are no general laws of society, but only cultural agreements
[Schauspielhaus Düsseldorf] / Elektra : Montag, den 21. Mai 1906 (Abonnements-Vorstellung) ; Tragödie in einem Akt
No full text(frei nach Sophokles) von Hugo v. Hofmannsthal. Regie: Arthur Holz. Dramatis Personae: Louise Dumont, Gertrud Seeliger, Fanny Ritter, Josef Klein, Bernhard Goetzke, Albert Fischer, Francis Gernoth, Elisabeth Sauer, Alfred Plange, Paul Henckels, Otto Fischer, Else Jansen, Helene Urfus, Claire Dunkel, Stephanie Kriß, Angelina Gurlitt, Eva Marterstei
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