149 research outputs found
From sea to land and beyond : new insights into the evolution of euthyneuran Gastropoda (Mollusca)
Background The Euthyneura are considered to be the most successful and diverse group of Gastropoda. Phylogenetically, they are riven with controversy. Previous morphology-based phylogenetic studies have been greatly hampered by rampant parallelism in morphological characters or by incomplete taxon sampling. Based on sequences of nuclear 18S rRNA and 28S rRNA as well as mitochondrial 16S rRNA and COI DNA from 56 taxa, we reconstructed the phylogeny of Euthyneura utilising Maximum Likelihood and Bayesian inference methods. The evolution of colonization of freshwater and terrestrial habitats by pulmonate Euthyneura, considered crucial in the evolution of this group of Gastropoda, is reconstructed with Bayesian approaches. Results We found several well supported clades within Euthyneura, however, we could not confirm the traditional classification, since Pulmonata are paraphyletic and Opistobranchia are either polyphyletic or paraphyletic with several clades clearly distinguishable. Sacoglossa appear separately from the rest of the Opisthobranchia as sister taxon to basal Pulmonata. Within Pulmonata, Basommatophora are paraphyletic and Hygrophila and Eupulmonata form monophyletic clades. Pyramidelloidea are placed within Euthyneura rendering the Euthyneura paraphyletic. Conclusion Based on the current phylogeny, it can be proposed for the first time that invasion of freshwater by Pulmonata is a unique evolutionary event and has taken place directly from the marine environment via an aquatic pathway. The origin of colonisation of terrestrial habitats is seeded in marginal zones and has probably occurred via estuaries or semi-terrestrial habitats such as mangroves
Classification of slag material by spectral induced polarization laboratory and field measurements
Historical slag dumps are of increasing interest due to economic, environmental or archaeological reasons. Geophysical investigations can help accessing the potential reuse of slag material to recover metallic raw material or for the estimation of the hazard potential of the buried slag material due to dissolution occurrence.In our study, we have investigated various slag material in the laboratory with the spectral induced polarization (SIP) method, obtained from different historical slag dumps, located in the Harz Mountains, Germany. We also present SIP results from field measurements at a historical slag dump where most of the slag samples reveal high amounts of iron, zinc, silica, and barium.Our results reveal a discrimination between three different slag grades (low, medium, high) by using the imaginary conductivity σ″ at a medium frequency (1–10 Hz) in both laboratory and field. Furthermore, additional information is obtained by a classification based on the spectral polarization behaviour and considering the field frequency range (0.1 Hz – 100 Hz). Five different types of spectra (ascending, descending, constant, maximum and minimum type) can be discriminated and recognized in the laboratory and in distinct areas of the slag dump. Even though a direct comparison between the laboratory and field results still needs to be proven, the buried slag material can be differentiated from the surrounding material by the polarization magnitude
Benthic meltwater fjord habitats formed by rapid glacier recession on King George Island, Antarctica
The coasts of West Antarctic Peninsula are strongly influenced by glacier meltwater discharge. The spatial structure and biogeochemical composition of inshore habitats is shaped by large quantities of terrigenous particulate material deposited in the vicinity of the coast, which impacts the pelagic and benthic ecosystems. We used a multitude of geochemical and environmental variables to identify the radius extension of meltwater impact of Fourcade Glacier into the fjord system of Potter Cove, King George Island. K-means cluster algorithm, canonical correspondence analysis, variance analysis and post-hoc Tukey's multiple comparison test were applied to define and cluster coastal meltwater habitats. A minimum of 10 clusters was needed to classify the 8 km2 study area into meltwater fjord habitats (MFH), fjord habitats and marine habitats. Strontium content in surface sediments is the main geochemical indicator for lithogenic creek discharge in Potter Cove. Furthermore, bathymetry, glacier distance and geomorphic positioning are the essential habitat explaining variables. Mean and maximum MFH extent amounted to 1 km and 2 km, respectively. Extrapolation of the identified meltwater impact ranges to King George Island coastlines which are presently ice-covered bays and fjord areas indicate an overall coverage of 200–400 km2 MFH, underpinning the importance to better understand the biology and biogeochemistry in terrestrial marine transition zones
Foresight study - Thematic Report IV: Secondary Raw Materials (Including Mine Wastes)
ABSTRACT: This thematic report has been developed within the Minerals4EU project in the context of the first Foresight Study report (WP6) that comprises a central report and five thematic reports. These contributions were designed according to a well-defined structure to fit the purposes of the central Foresight Study report. The scope and targets of the first Foresight Study significantly determine the nature of the documents and may not be suited for unspecified or differing purposes.N/
Dopamine synthesis and dopamine receptor expression are disturbed in recurrent miscarriages
Objectives: L-dopa decarboxylase (DDC) is responsible for the synthesis of dopamine. Dopamine, which binds to the D-2-dopamine receptor (D2R), plays an important role in the maintenance of pregnancy. Aim of our study was the analysis of DDC and D2R expression in placentas of spontaneous miscarriages (SMs) and recurrent miscarriages (RMs) in comparison to healthy controls. Methods: Patients with SM (n=15) and RM (n=15) were compared with patients from healthy pregnancies (n=15) (pregnancy weeks 7-13 each). Placental tissue has been collected from SMs and RMs from the first trimester (Department of Gynaecology and Obstetrics, LMU Munich) and from abruptions (private practice, Munich). Placental cell lines, BeWo- and JEG-3 cells, were stimulated with the trace amines T(0)AM and T(1)AM in vitro. Results: Levels of DDC and D2R in trophoblasts and the decidua were lower in RMs in comparison to healthy controls. Stimulation of BeWo cells with T(1)AM significantly reduced DDC mRNA and protein levels. Via double-immunofluorescence, a DDC-positive cell type beneath decidual stromal cells and foetal EVT in the decidua could be detected. Conclusions: Downregulation of DDC and D2R in trophoblasts of RMs reflects a reduced signal cascade of catecholamines on the foetal side
TAAR1 induces a disturbed GSK3 β phosphorylation in recurrent miscarriages through the ODC
Objectives: Thyroid hormones play an important role in the maintenance of pregnancy. Their derivates, endogenous amines, act via binding to the trace amine-associated receptor (TAAR1). The aim of our study was to analyse the regulation of TAAR1, serine/threonine kinase (pGSK3 beta) and ornithine decarboxylase (ODC) in placentas of healthy pregnancies, spontaneous (SM) and recurrent miscarriages (RM) and to investigate the influence of thyroid hormone derivates on TAAR1 expression in trophoblast model cells in vitro. Methods: Patients with SM (n = 15) and RM (n = 15) were compared with patients with healthy pregnancies (n = 15) (pregnancy weeks 7-13 each). Immunohistochemistry was applied to analyse placental TAAR1, pGSK3 beta and ODC expression. Protein expression of the receptors after stimulation with T-3, T(1)AM and RO5203548 in BeWo trophoblast model cells was determined via Western blot. Double-immunofluorescence was used to determine placental expression of TAAR1 and ODC. Results: Levels of TAAR1, pGSK3 beta and ODC were higher in placentas of RM in comparison to healthy controls. Stimulation of BeWo cells with T-3, T(1)AM and RO5203548 significantly increased TAAR1 expression. ODC expression in BeWo cells was upregulated through T-3. Via double-immunofluorescence, TAAR1 and ODC-positive EVT could be detected. Conclusions: Upregulation of placental TAAR1 may indicate an increased decarboxylation of thyroid hormones in miscarriages. Patients with RM may have a lack of T-3 through an enhanced transformation of T-3 into T(1)AM induced by the ODC. Future investigations could be carried out to analyse what role a prophylactic T-3 substitution plays for patients
Bamberg in the Early Modern Period. New Essays on the History of Town and Bishopric
Die Beiträge dieses Bandes behandeln Aspekte der Verwaltungs-, Herrschafts-, Wirtschafts-, Sozial- und Kulturgeschichte Bambergs zwischen 1500 und 1800 und schließen damit einige der weißen Flecken auf der Landkarte der frühneuzeitlichen Stadt- und Regionalforschung. Zugleich werden aktuelle geschichtswissenschaftliche Fragestellungen und Konzepte empirisch erprobt. Damit sollen die Möglichkeiten, die Bamberg als Forschungsfeld bietet, und das Potential, das sich mit der Anwendung von Konzepten und Methoden der modernen Geschichtswissenschaft auf das reichhaltige Bamberger Material verbindet, aufgezeigt und Anregungen für künftige Forschungen gegeben werden.The essays in this volume cover aspects of Bamberg’s political, administrative, economic, social and cultural history from 1500 to 1800 and thus close some of the gaps in the city’s and region’s historiography. At the same time the essays provide empirical explorations of current scholarly concepts and approaches. They intend to point out the possibilities which Bamberg offers as a field of research and the potentials inherent in the application of modern historical concepts and methods on the rich source materials available for Bamberg
VLT/NACO Polarimetric Differential Imaging of HD100546 - Disk Structure and Dust Grain Properties between 10-140 AU
We present polarimetric differential imaging (PDI) data of the circumstellar
disk around the Herbig Ae/Be star HD100546 obtained with VLT/NACO. We resolve
the disk in polarized light in the H and Ks filter between ~0.1-1.4" (i.e.,
~10-140 AU). The innermost disk regions are directly imaged for the first time
and the mean apparent disk inclination and position angle are derived. The
surface brightness along the disk major axis drops off roughly with S(r) ~ r^-3
but has a maximum around 0.15" suggesting a marginal detection of the main disk
inner rim at ~15 AU. We find a significant brightness asymmetry along the disk
minor axis in both filters with the far side of the disk appearing brighter
than the near side. This enhanced backward scattering and a low total
polarization degree of the scattered disk flux of 14%(+19%/-8%) suggests that
the dust grains on the disk surface are larger than typical ISM grains.
Empirical scattering functions reveal the backward scattering peak at the
largest scattering angles and a second maximum for the smallest scattering
angles. This indicates a second dust grain population preferably forward
scattering and smaller in size. It shows that, relatively, in the inner disk
regions (40-50 AU) a higher fraction of larger grains is found compared to the
outer disk regions (100-110 AU). Finally, our images reveal distinct
substructures between 25-35 AU physical separation from the star and we discuss
the possible origin for the two features in the context of ongoing planet
formation.Comment: Accepted for publication by Ap
Der Klang der Lyrik: Zur Konzeptualisierung von Sprecher und Stimme, auch für die computationelle Analyse
Das Forschungsprojekt »textklang«: Mixed-Methods-Analyse von Lyrik in Text und Ton (gefördert durch das Bundesministerium für Bildung und Forschung) zielt auf die systematische und diachrone Untersuchung der Beziehung zwischen literarischen Texten, insbesondere Lyrik der Romantik, und ihrer lautsprachlichen Realisierung bei der Rezitation oder der musikalischen Aufführung. Die Vorstellungen von Mündlichkeit, Klang und Stimme, die im Besonderen mit der Lyrik verbunden sind, werden empirisch untersucht und auch im Sinne moderner Ansätze der Lyrikanalyse theoretisiert. Besondere Bedeutung kommt dabei dem experimentellen Ansatz der Sprachsynthese zu, also der computationellen Möglichkeit, eine menschliche Sprechstimme künstlich herzustellen; er ermöglicht es, eine idealtypische Realisierung des Textes zu ermitteln und menschliche Realisierungen auf ihre ästhetische Besonderheit hin zu testen.The research project »text sound«: mixed-methods-analysis of lyric poetry in text and tonal sound (funded by the Federal Ministry for Education and Research, BMBF) aims to undertake a systematic and diachronic investigation of the relationship between literary texts, especially lyric poetry from the Romantic period, and their phonetic realisation in recitations or musical performances. Ideas of orality, sound and voice, which are particularly associated with poetry, are investigated empirically and also theorised in the line with modern approaches to the analysis of lyric poetry. Of particular importance is the experimental approach of speech synthesis, i.e. using computers to artificially produce a human sounding voice; this approach makes it possible to explore an ideal-typical realisation of the text and to test the aesthetic peculiarity of human realisations
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