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Book ; Online: Methan concentration and delta deuterium of methane from the NGRIP ice core, supplementary data to: Bock, Michael; Schmitt, Jochen; M?ller, Lars; Spahni, Renato; Blunier, Thomas; Fischer, Hubertus (2010): Hydrogen isotopes preclude marine hydrate CH4 emissions at the onset of Dansgaard-Oeschger Events. Science, 328(5986), 1686-1689

Bock, Michael / Blunier, Thomas / Fischer, Hubertus / M?ller, Lars / Schmitt, Jochen / Spahni, Renato

2010

Abstract: The causes of past changes in the global methane cycle and especially the role of marine methane hydrate (clathrate) destabilization events are a matter of debate. Here we present evidence from the North Greenland Ice Core Project ice core based on the ... ...

Abstract	The causes of past changes in the global methane cycle and especially the role of marine methane hydrate (clathrate) destabilization events are a matter of debate. Here we present evidence from the North Greenland Ice Core Project ice core based on the hydrogen isotopic composition of methane [dD(CH4)] that clathrates did not cause atmospheric methane concentration to rise at the onset of Dansgaard-Oeschger (DO) events 7 and 8. Box modeling supports boreal wetland emissions as the most likely explanation for the interstadial increase. Moreover, our data show that dD(CH4) dropped 500 years before the onset of DO 8, with CH4 concentration rising only slightly. This can be explained by an early climate response of boreal wetlands, which carry the strongly depleted isotopic signature of high-latitude precipitation at that time.
Language	English
Dates of publication	2010-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1126/science.1187651
DOI	10.1594/PANGAEA.756715
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Susceptibility, conductivity and porosity along a GEM-SHARK profile, supplementary data to: Rey, Daniel; M?ller, Hendrik; Rubio, Belen; von Dobeneck, Tilo; Vilas, F; Hilgenfeldt, C; Bernabeu, A; Frederichs, Thomas; Fern?ndez, S; Mohamed, KJ; Grupo GEOMA (2008): Using electromagnetic sensors to estimate physical properties and environmental quality of surface sediments in the marine environment. Preliminary results. Geotemas, 10, 652-654

M?ller, Hendrik / Bernabeu, A / Fern?ndez, S / Frederichs, Thomas / Hilgenfeldt, C / Mohamed, KJ / Rubio, Belen / Vilas, F / von Dobeneck, Tilo / Grupo GEOMA

2010

Abstract: The coastal systems, are often subjected to high anthropogenic pressure, which makes it necessary to develop new techniques to assess the environmental impacts caused by such human activity. This paper presents the first results obtained during the ... ...

Abstract	The coastal systems, are often subjected to high anthropogenic pressure, which makes it necessary to develop new techniques to assess the environmental impacts caused by such human activity. This paper presents the first results obtained during the development and implementation of a new equipment of submarine geophysics survey oriented to integrated coastal zone management (ICZM). It is based on the drag of a submarine in contact with the sea-bottom. The submarine is equipped with an electromagnetic sensor which allows the measurement of the magnetic susceptibility and electrical conductivity of the surface sediments continuously and to a depth of sediment of 40 cm. This system, once improved, will allow us to obtain valuable information for monitoring the environmental quality of coastal areas.
Language	English
Dates of publication	2010-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
DOI	10.1594/PANGAEA.742075
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Organic carbon concentrations and isotope ratios of sediments from the Laptev Sea, supplementary data to: M?ller-Lupp, Thomas; Bauch, Henning A; Erlenkeuser, Helmut; Hefter, Jens; Kassens, Heidemarie; Thiede, J?rn (2000): Changes in the deposition of terrestrial organic matter on the Laptev Sea shelf during the Holocene: evidence from stable carbon isotopes. International Journal of Earth Sciences, 89(3), 563-568

M?ller-Lupp, Thomas / Bauch, Henning A / Erlenkeuser, Helmut / Hefter, Jens / Kassens, Heidemarie / Thiede, J?rn

2000

Abstract: ... depths between 46 and 77 m, specify the spatial and temporal changes in the deposition of terrestrial ...

Abstract	Stable carbon isotope ratios in the organic fraction of surface sediments from the Laptev Sea shelf were analyzed in order to study the modern distribution pattern of terrestrial organic matter. The delta13Corg signature of the surface sediments range from -26.6? near the coastal margin to -22.8? in the north towards the outer shelf. Characterizing the possible sources of organic matter by their delta13Corg signature reveals that the terrestrial influence reaches further north in the eastern than in the western Laptev Sea. Downcore records of the delta13Corg, measured on three AMS 14C-dated cores from water depths between 46 and 77 m, specify the spatial and temporal changes in the deposition of terrestrial organic matter on the Laptev Sea shelf during the past 12.7 ka. The major depositional changes of terrestrial organic matter occurred between 11 and 7 ka and comprised the main phase of the southward retreat of the coastline and of the river depocenters due to the postglacial sea level rise.
Language	English
Dates of publication	2000-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1007/s005310000128
DOI	10.1594/PANGAEA.712058
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Article ; Online: Silent Cerebral Events after Atrial Fibrillation Ablation � Overview and Current Data

Thomas Deneke / Karin Nentwich / Joachim Krug / Patrick M�ller / Peter Hubert Grewe / Andreas M�gge / Anja Schade

Journal of Atrial Fibrillation, Vol 6, Iss 5, Pp 64-

2014 Volume 69

Abstract: Silent cerebral lesions (SCL) have been identified on brain magnetic resonance imaging (MRI) in apparently asymptomatic patients after cardiovascular procedures. After atrial fibrillation (AF) ablation incidences range from 1 to over 40% depending upon ... ...

Abstract	Silent cerebral lesions (SCL) have been identified on brain magnetic resonance imaging (MRI) in apparently asymptomatic patients after cardiovascular procedures. After atrial fibrillation (AF) ablation incidences range from 1 to over 40% depending upon different factors. MRI definition should include diffusion weighted imaging (DWI) to detect hyperintensities (bright spots) due to acute brain ischemia correlated with a hypointensity in the apparent diffusion coefficient mapping (ADC-map) to rule out artifacts. The genesis of SCL appears to be multifactorial and appears to be a result of embolic events either from gaseous or solid particles. The MRI pattern appears to be comparable not hinting towards a specific mechanism. One may distinguish two different MRI patterns, for one silent cerebral ischemic events not proven to be related to cell death (DWI positive but FLAIR negative) and MRI findings that are due to edema caused by cell death which will lead to glial cell scar formation (DWI positive and FLAIR positive). For ease of data interpretation, future studies should ensure that DWI and FLAIR data is acquired using identical slice thickness and orientation. Risk factors associated with increased SCL-incidences involve patient-specific, technology-associated and procedural determinants. When using a high-sensitive MRI definition differences in ischemic brain event-rates in between technologies appear to be less prominent. Further studies on the effects of different periprocedural anticoagulation regimen, different steps of the ablation procedure and new technologies are needed. For now, SCL incidence may determine the thrombogenic potential of an ablation technology and further studies to reduce or avoid SCL generation are desirable. It appears reasonable, that any cerebral ischemic event should be avoided.
Keywords	Internal medicine ; RC31-1245 ; Medicine ; R
Subject code	610
Language	English
Publishing date	2014-02-01T00:00:00Z
Publisher	CardioFront
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Himalayan treeline soil and foliar C:N:P stoichiometry indicate nutrient shortage with elevation

MÃ¼ller, Michael / JÃ¼rgen BÃ¶hner / Thomas Scholten / Udo Schickhoff / Yvonne Oelmann

Geoderma. 2017 Apr. 01, v. 291

2017

Abstract: Only a few studies have addressed the soil and foliar carbon:nitrogen:phosphorus (C:N:P) stoichiometry in alpine treeline ecotones. Moreover, information on the soil nutrient availability (primarily N, P) in such ecosystems is rare. To fill these gaps, ... ...

Abstract	Only a few studies have addressed the soil and foliar carbon:nitrogen:phosphorus (C:N:P) stoichiometry in alpine treeline ecotones. Moreover, information on the soil nutrient availability (primarily N, P) in such ecosystems is rare. To fill these gaps, we performed a multiple data sampling in a near-natural alpine treeline ecotone in Rolwaling Himal, Nepal.Our results show strongly varying soil C:N:P ratios and nutrient availability with soil depth. Caused by high monsoon precipitation and coarse-grained soils with low water-holding capacities, a vertical transport of nutrients and potentially mineralizable soil organic matter (SOM) in soils occurs, which is a general problem in the study area impeding growing conditions for trees. Soil N and P availability, and soil C:P and N:P ratios decrease significantly as elevation increases, especially at the transition from krummholz (dominated by Rhododendron campanulatum) to the alpine tundra (dwarf scrub heath). Soil C:N ratios increase significantly with elevation, most notably from the subalpine forest to krummholz and the alpine tundra. These altitudinal trends indicate increasing nutrient (N, P) shortage especially in the alpine tundra. Low N and P availability in alpine tundra soils are likely caused by a lower litter input from dwarf shrub vegetation, and a decline in litter mineralization in this altitudinal zone resulting in small accumulation of SOM. Nutrient availability in the entire study area is generally limited by low soil pH (from 2.5 to 4). In total six investigated tree species show diverse relationships between foliar and soil stoichiometric ratios, and soil nutrient availability. Significantly increasing foliar C:N and C:P ratios with elevation due to significantly decreasing foliar N and P concentrations suggest a limitation in N and P. Foliar N:P ratios indicate N rather than P limitation. Contrary to previous studies from different alpine treeline ecotones, we do not consider the Rolwaling treeline ecotone as an area of nutrient accumulation. We conclude that altitudinal variations in stand structures themselves govern nutrient cycling through the input of C, N, and P into soils by differences in leaf fall.
Keywords	alpine tundra ; biogeochemical cycles ; carbon nitrogen ratio ; coarse-textured soils ; ecosystems ; ecotones ; krummholz ; leaves ; mineralization ; monsoon season ; nutrient availability ; nutrients ; Rhododendron ; shrublands ; shrubs ; soil depth ; soil nutrients ; soil organic matter ; soil pH ; stoichiometry ; treeline ; trees ; tundra soils ; water holding capacity
Language	English
Dates of publication	2017-0401
Size	p. 21-32.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	281080-3
ISSN	1872-6259 ; 0016-7061
ISSN (online)	1872-6259
ISSN	0016-7061
DOI	10.1016/j.geoderma.2016.12.015
Database	NAL-Catalogue (AGRICOLA)

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Article: Soil Temperature and Soil Moisture Patterns in a Himalayan Alpine Treeline Ecotone

MÃ¼ller, Michael / BÃ¶hner JÃ¼rgen / Schickhoff Udo / Scholten Thomas / Schwab Niels

Arctic, Antarctic, and Alpine Research. 2016 Aug., v. 48, no. 3

2016

Abstract: Soil properties in alpine treeline ecotones are insufficiently explored. In particular, an extensive monitoring of soil moisture conditions over a longer period of time is rare, and the effects of soil moisture variability on alpine treelines have not ... ...

Abstract	Soil properties in alpine treeline ecotones are insufficiently explored. In particular, an extensive monitoring of soil moisture conditions over a longer period of time is rare, and the effects of soil moisture variability on alpine treelines have not received adequate attention yet. Soil temperature patterns are generally well documented, and soil temperature is considered a key factor in limiting tree growth at both global and local scales. We performed a 2Â½-year monitoring in a near-natural treeline ecotone in Rolwaling Himal, Nepal. In this paper, we present new findings on spatiotemporal soil temperature and moisture variability in relation to topographical features and vegetation patterns (variations in stand structures and tree physiognomy). Our results show a growing season mean soil temperature of 7.5 Â± 0.6 Â°C at 10 cm depth at the Rolwaling treeline. Multivariate statistical analyses yield a significant relation between soil temperatures and the variability in tree height, crown length, crown width, and leaf area index (LAI). In turn, soil temperature variability is controlled by the tree physiognomy itself. Soil moisture conditions (available water capacity, 0â10 cm) appear to be less substantial for current stand structures and tree physiognomy. In turn, tree physiognomy patterns control soil moisture, which additionally is affected by snow cover. In Rolwaling, shallow and coarse-grained soils cause low water-holding capacities, and thus a remarkable amount of water percolates from topsoils to subsoils. In the alpine tundra with missing forest canopy, year-round lowest available water capacities are additionally caused by high solar radiation, wind, and thus high evaporation. We assume low soil moisture availability causing largely prevented tree regeneration especially in the alpine tundra.We conclude that soil temperature and moisture patterns reflect tree physiognomy patterns. The latter cause disparities in soil temperature and moisture conditions inside and outside of the closed forest by shading effects and differences in leaf fall.
Keywords	alpine tundra ; available water capacity ; coarse-textured soils ; ecotones ; evaporation ; forest canopy ; forests ; growing season ; leaf area index ; leaves ; monitoring ; multivariate analysis ; shade ; snowpack ; soil temperature ; soil water ; solar radiation ; topsoil ; tree growth ; treeline ; trees ; water holding capacity ; wind ; Nepal
Language	English
Dates of publication	2016-08
Size	p. 501-521.
Publishing place	Institute of Arctic and Alpine Research (INSTAAR), University of Colorado
Document type	Article
ZDB-ID	2045941-5
ISSN	1938-4246 ; 1523-0430
ISSN (online)	1938-4246
ISSN	1523-0430
DOI	10.1657%2FAAAR0016-004
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Reverse Time Migration

Sabine Müller / Ernst Niederleithinger / Thomas Bohlen

International Journal of Geophysics, Vol

A Seismic Imaging Technique Applied to Synthetic Ultrasonic Data

2012 Volume 2012

Keywords	Geophysics. Cosmic physics ; QC801-809 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Geophysics and Geomagnetism ; DOAJ:Earth and Environmental Sciences
Language	English
Publishing date	2012-01-01T00:00:00Z
Publisher	Hindawi Publishing Corporation
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Application of BaO-Based Sulfur Sorbent for in Situ Desulfurization of Biomass-Derived Syngas

Husmann, Moritz / Hochenauer Christoph / Kienberger Thomas / Maitz Viktoria / MuÌller Michael / Zuber Christian

Energy & Fuels. 2016 Aug. 18, v. 30, no. 8

2016

Abstract: A novel BaO-based sorbent is tested for in situ application as desulfurization agent in an allothermal biomass gasification process. BaO is stabilized against the formation of carbonate and thus theoretically allows desulfurization down to a few parts ... ...

Abstract	A novel BaO-based sorbent is tested for in situ application as desulfurization agent in an allothermal biomass gasification process. BaO is stabilized against the formation of carbonate and thus theoretically allows desulfurization down to a few parts per million (volume) (ppmáµ¥) HâS even for high-steam and high-temperature conditions. In real process application, sintering of the sorbent occurred and had to be prevented by the addition of lime as separating agent. Additionally, a kinetic limitation of the desulfurization with BaO was shown for the in-bed sorption of sulfur. An increase of gasification temperature from 760 to 810 Â°C significantly improved the desulfurization performance. The observed behavior is in contrast to that of previously tested CaO-based in situ sorbents. CaO-based in situ desulfurization is limited to values of about 500 ppmáµ¥ HâS for the conditions prevailing in the gasifier. With the novel BaO-based sorbent, a desulfurization from 85 to 35 ppmáµ¥ residual HâS is shown upon addition of the sorbent to the gasifier. In experiments with a combined desulfurization of CaO and BaO, a release of HâS from CaS was shown once the HâS content in the gas drops below the CaO-based steady-state equilibrium of desulfurization. Particle analysis via SEM-EDX, XRD, ICP-OES, and BET complement the results of in situ desulfurization. SEM-EDX results indicate the stabilization of BaO in sintering bridges and a certain depletion of barium from the sorbent after in-bed application.
Keywords	barium ; biomass ; calcium oxide ; desulfurization ; energy-dispersive X-ray analysis ; gasification ; hydrogen sulfide ; scanning electron microscopy ; sorbents ; sorption ; sulfur ; synthesis gas ; temperature ; X-ray diffraction
Language	English
Dates of publication	2016-0818
Size	p. 6458-6466.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1483539-3
ISSN	1520-5029 ; 0887-0624
ISSN (online)	1520-5029
ISSN	0887-0624
DOI	10.1021%2Facs.energyfuels.6b00957
Database	NAL-Catalogue (AGRICOLA)

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Article: Ciliogenesis and cerebrospinal fluid flow in the developing Xenopus brain are regulated by foxj1.

Hagenlocher, Cathrin / Walentek, Peter / M Ller, Christina / Thumberger, Thomas / Feistel, Kerstin

Cilia

2013 Volume 2, Issue 1, Page(s) 12

Abstract: Background: Circulation of cerebrospinal fluid (CSF) through the ventricular system is driven by motile cilia on ependymal cells of the brain. Disturbed ciliary motility induces the formation of hydrocephalus, a pathological accumulation of CSF ... ...

Abstract	Background: Circulation of cerebrospinal fluid (CSF) through the ventricular system is driven by motile cilia on ependymal cells of the brain. Disturbed ciliary motility induces the formation of hydrocephalus, a pathological accumulation of CSF resulting in ventricle dilatation and increased intracranial pressure. The mechanism by which loss of motile cilia causes hydrocephalus has not been elucidated. The aim of this study was: (1) to provide a detailed account of the development of ciliation in the brain of the African clawed frog Xenopus laevis; and (2) to analyze the relevance of ependymal cilia motility for CSF circulation and brain ventricle morphogenesis in Xenopus. Methods: Gene expression analysis of foxj1, the bona fide marker for motile cilia, was used to identify potentially ciliated regions in the developing central nervous system (CNS) of the tadpole. Scanning electron microscopy (SEM) was used to reveal the distribution of mono- and multiciliated cells during successive stages of brain morphogenesis, which was functionally assessed by bead injection and video microscopy of ventricular CSF flow. An antisense morpholino oligonucleotide (MO)-mediated gene knock-down that targeted foxj1 in the CNS was applied to assess the role of motile cilia in the ventricles. Results: RNA transcripts of foxj1 in the CNS were found from neurula stages onwards. Following neural tube closure, foxj1 expression was seen in distinct ventricular regions such as the zona limitans intrathalamica (ZLI), subcommissural organ (SCO), floor plate, choroid plexus (CP), and rhombomere boundaries. In all areas, expression of foxj1 preceded the outgrowth of monocilia and the subsequent switch to multiciliated ependymal cells. Cilia were absent in foxj1 morphants, causing impaired CSF flow and fourth ventricle hydrocephalus in tadpole-stage embryos. Conclusions: Motile ependymal cilia are important organelles in the Xenopus CNS, as they are essential for the circulation of CSF and maintenance of homeostatic fluid pressure. The Xenopus CNS ventricles might serve as a novel model system for the analysis of human ciliary genes whose deficiency cause hydrocephalus.
Language	English
Publishing date	2013-09-24
Publishing country	England
Document type	Journal Article
ZDB-ID	2689513-4
ISSN	2046-2530
ISSN	2046-2530
DOI	10.1186/2046-2530-2-12
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: 3D reconstruction of SARS-CoV-2 infection in ferrets emphasizes focal infection pattern in the upper respiratory tract

Zaeck, Luca M. / Scheibner, David / Sehl, Julia / MÃ¼ller, Martin / Hoffmann, Donata / Beer, Martin / Abdelwhab, Elsayed M. / Mettenleiter, Thomas C. / Breithaupt, Angele / Finke, Stefan

bioRxiv

Abstract: The visualization of viral pathogens in infected tissues is an invaluable tool to understand spatial virus distribution, localization, and cell tropism in vivo. Commonly, virus-infected tissues are analyzed using conventional immunohistochemistry in ... ...

Abstract	The visualization of viral pathogens in infected tissues is an invaluable tool to understand spatial virus distribution, localization, and cell tropism in vivo. Commonly, virus-infected tissues are analyzed using conventional immunohistochemistry in paraffin-embedded thin sections. Here, we demonstrate the utility of volumetric three-dimensional (3D) immunofluorescence imaging using tissue optical clearing and light sheet microscopy to investigate host-pathogen interactions of pandemic SARS-CoV-2 in ferrets at a mesoscopic scale. The superior spatial context of large, intact samples (> 150 mm3) allowed detailed quantification of interrelated parameters like focus-to-focus distance or SARS-CoV-2-infected area, facilitating an in-depth description of SARS-CoV-2 infection foci. Accordingly, we could confirm a preferential infection of the ferret upper respiratory tract by SARS-CoV-2 and emphasize a distinct focal infection pattern in nasal turbinates. Conclusively, we present a proof-of-concept study for investigating critically important respiratory pathogens in their spatial tissue morphology and demonstrate the first specific 3D visualization of SARS-CoV-2 infection.
Keywords	covid19
Publisher	BioRxiv; WHO
Document type	Article ; Online
Note	WHO #Covidence: #339051
DOI	10.1101/2020.10.17.339051
Database	COVID19

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