184 results on '"Hartmut Schulz"'
Search Results
2. Discharges of dust from NORM facilities: Key parameters to assess effective doses for public exposure
- Author
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Christian Kunze, Hartmut Schulz, Eckard Ettenhuber, Astrid Schellenberger, and Jörg Dilling
- Subjects
Mining engineering. Metallurgy ,TN1-997 - Abstract
In transposing Directive 2013/59/Euratom (European Basic Safety Standards or EU BSS) into national law, it was necessary to identify industrial sectors which involve naturally occurring radioactive materials (NORM) which may lead to public exposure that cannot be disregarded from a radiation protection point of view. A research project was implemented that resulted in a comprehensive survey of all potentially relevant industrial sectors operating in Germany. Major efforts were made to determine source terms of airborne discharges, atmospheric dispersion models, and dose calculations.The study arrived at the conclusion that the discharge and the settlement of dust in agricultural and horticultural areas is the most relevant dispersion and exposure pathway, while discharges of radon are of minor importance.The original study used a number of rather complex models that may distract from the fact that very few key parameters and assumptions determine the effective dose of members of the public. This paper revisits the study and identifies those parameters and assumptions and provides a simplified, generic, yet sufficiently reliable and robust assessment methodology to determine the radiological relevance of dust discharges from NORM industries under the typical geographical and meteorological conditions of Germany.This paper provides examples of dose estimates for members of the public for selected industries operating in Germany. Due to its simplicity and robustness, the methodology can also be used to assess effective doses resulting from discharges in other industries in Germany, and it can be adapted to conditions in other countries in a straightforward way. Keywords: NORM, Dust discharge, Public exposure, High temperature processes, Atmospheric dispersion model
- Published
- 2019
- Full Text
- View/download PDF
3. Detection and Characterisation of Eemian Marine Tephra Layers within the Sapropel S5 Sediments of the Aegean and Levantine Seas
- Author
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Christopher Satow, Katharine M. Grant, Sabine Wulf, Hartmut Schulz, Addison Mallon, Ian Matthews, and John Lowe
- Subjects
quaternary ,palaeoceanography ,europe ,sedimentology-marine cores ,tephrochronology ,eemian ,Human evolution ,GN281-289 ,Stratigraphy ,QE640-699 - Abstract
The Eemian was the last interglacial period (~130 to 115 ka BP) to precede the current interglacial. In Eastern Mediterranean marine sediments, it is marked by a well-developed and organic-rich “sapropel” layer (S5), which is thought to reflect an intensification and northward migration of the African monsoon rain belt over orbital timescales. However, despite the importance of these sediments, very little proxy-independent stratigraphic information is available to enable rigorous correlation of these sediments across the region. This paper presents the first detailed study of visible and non-visible (cryptotephra) layers found within these sediments at three marine coring sites: ODP Site 967B (Levantine Basin), KL51 (South East of Crete) and LC21 (Southern Aegean Sea). Major element analyses of the glass component were used to distinguish four distinct tephra events of Santorini (e.g., Vourvoulos eruption) and possible Anatolian provenance occurring during the formation of S5. Interpolation of core chronologies provides provisional eruption ages for the uppermost tephra (unknown Santorini, 121.8 ± 2.9 ka) and lowermost tephra (Anatolia or Kos/Yali/Nisyros, 126.4 ± 2.9 ka). These newly characterised tephra deposits have also been set into the regional tephrostratigraphy to illustrate the potential to precisely synchronise marine proxy records with their terrestrial counterparts, and also contribute to the establishment of a more detailed volcanic history of the Eastern Mediterranean.
- Published
- 2020
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4. End-member modelling as a tool for climate reconstruction-An Eastern Mediterranean case study.
- Author
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Sarah Beuscher, Stefan Krüger, Werner Ehrmann, Gerhard Schmiedl, Yvonne Milker, Helge Arz, and Hartmut Schulz
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Medicine ,Science - Abstract
The Eastern Mediterranean Sea is a sink for terrigenous sediments from North Africa, Europe and Asia Minor. Its sediments therefore provide valuable information on the climate dynamics in the source areas and the associated transport processes. We present a high-resolution dataset of sediment core M40/4_SL71, which was collected SW of Crete and spans the last ca. 180 kyr. We analysed the clay mineral composition, the grain size distribution within the silt fraction, and the abundance of major and trace elements. We tested the potential of end-member modelling on these sedimentological datasets as a tool for reconstructing the climate variability in the source regions and the associated detrital input. For each dataset, we modelled three end members. All end members were assigned to a specific provenance and sedimentary process. In total, three end members were related to the Saharan dust input, and five were related to the fluvial sediment input. One end member was strongly associated with the sapropel layers. The Saharan dust end members of the grain size and clay mineral datasets generally suggest enhanced dust export into the Eastern Mediterranean Sea during the dry phases with short-term increases during Heinrich events. During the African Humid Periods, dust export was reduced but may not have completely ceased. The loading patterns of two fluvial end members show a strong relationship with the Northern Hemisphere insolation, and all fluvial end members document enhanced input during the African Humid Periods. The sapropel end member most likely reflects the fixation of redox-sensitive elements within the anoxic sapropel layers. Our results exemplify that end-member modelling is a valuable tool for interpreting extensive and multidisciplinary datasets.
- Published
- 2017
- Full Text
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5. Nitrate reduction potential of a fractured Middle Triassic carbonate aquifer in Southwest Germany
- Author
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Karsten Osenbrück, Eva Blendinger, Carsten Leven, Hermann Rügner, Michael Finkel, Natalia Jakus, Hartmut Schulz, and Peter Grathwohl
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Earth and Planetary Sciences (miscellaneous) ,Water Science and Technology - Abstract
Nitrate reduction constitutes an important natural mechanism to mitigate the widespread and persistent nitrate contamination of groundwater resources. In fractured aquifers, however, the abundance and accessibility of electron donors and their spatial correlation with groundwater flow paths are often poorly understood. In this study, the nitrate reduction potential of a fractured carbonate aquifer in the Upper Muschelkalk of SW Germany was investigated, where denitrification is due to the oxidation of ferrous iron and reduced sulfur. Petrographical analyses of rock samples revealed concentrations of syn-sedimentary and diagenetically formed pyrite ranging from 1 to 4 wt.% with only small differences between different facies types. Additional ferrous iron is available in saddle dolomites (up to 2.6 wt.%), which probably were formed by tectonically induced percolation of low-temperature hydrothermal fluids. Borehole logging at groundwater wells (flowmeter, video, gamma) indicates that most groundwater flow occurs along karstified bedding planes partly located within dolomites of the shoal and backshoal facies. The high porosity (15–30%) of these facies facilitates molecular diffusive exchange of solutes between flow paths in the fractures and the reactive minerals in the pore matrix. The high-porosity facies together with hydraulically active fractures featuring pyrite or saddle dolomite precipitates constitute the zones of highest nitrate reduction potential within the aquifer. Model-based estimates of electron acceptor/donor balances indicate that the nitrate reduction potential protecting water supply wells increases with increasing porosity of the rock matrix and decreases with increasing hydraulic conductivity (or effective fracture aperture) and spacing of the fracture network.
- Published
- 2021
- Full Text
- View/download PDF
6. Chronology of detrital carbonate events in Baffin Bay reveals different timing but similar average recurrence time of North American-Arctic and Laurentide ice sheet collapse events during MIS 3
- Author
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Rebecca Jackson, Thomas Frederichs, Hartmut Schulz, and Michal Kucera
- Subjects
Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) - Abstract
Baffin Bay Detrital Carbonate (BBDC) layers represent periods of elevated discharge of terrigenoussediments, icebergs and freshwater originating from the North American Arctic-ice sheet complex.Distinct from Heinrich event layers in their dolomitic composition, these sedimentary deposits arefound throughout Baffin Bay. They are considered a signature of large-scale instability of the ice sheetsdischarging into the Baffin Bay, akin to the Heinrich events of the North Atlantic. However, the precisetiming of and potential forcing mechanisms for the North American Arctic-ice sheet instabilities remainselusive. Previous work suggests that BBDC events were not in phase with Heinrich events originating fromthe Hudson Strait, but this hypothesis could not be tested without rigorous chronological constraints.By combining radiocarbon ages and relative paleointensity (RPI) dating in a central western Baffin Baymarine sedimentary sequence, we were able to derive a new chronology for BBDC events covering a largepart of MIS3. Sedimentological and elemental data indicate the occurrence of seven distinct BBDC eventsover the last 52 ka. These events occur during both glacials (stadials) and interglacials (interstadials)and have no consistent phase relationship with Heinrich events. However, the mean duration and meanrecurrence time of BBDC events appears similar to Heinrich events. We conclude that BBDC events reflectrepeated ice sheet instability periods, with similar statistical properties but different timing compared tothe Heinrich events. This implies that episodic instability was an intrinsic property of the North AmericanArctic-ice sheet complex as well, but over the studied period of MIS3, instabilities of the Arctic and theLaurentide Ice sheets did not appear to have been linked.
- Published
- 2023
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7. Global temperature calibration of the Long chain Diol Index in marine surface sediments
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Andreas Lückge, Jan-Berend W Stuut, Jochen Knies, Julie Lattaud, Marijke W de Bar, Stefan Schouten, Geert-Jan A Brummer, Gabriella M. Weiss, Sebastiaan W Rampen, Darci Rush, Hartmut Schulz, Caglar Yildiz, Barbara Donner, Furu Mienis, Jaap S. Sinninghe Damsté, Jung-Hyun Kim, Nicole J. Bale, non-UU output of UU-AW members, and Earth and Climate
- Subjects
010504 meteorology & atmospheric sciences ,River runoff ,Diol ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Oseanografi: 452 ,010502 geochemistry & geophysics ,Atmospheric sciences ,01 natural sciences ,chemistry.chemical_compound ,Freshwater ,Geochemistry and Petrology ,VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452 ,14. Life underwater ,SDG 14 - Life Below Water ,Long-chain diols ,0105 earth and related environmental sciences ,Global temperature ,Proboscia ,Calibration Error ,6. Clean water ,SST ,Sea surface temperature ,chemistry ,13. Climate action ,Environmental science ,Proboscia diatoms ,LDI core-top calibration ,Long chain - Abstract
The Long chain Diol Index (LDI) is a relatively new organic geochemical proxy for sea surface temperature (SST), based on the abundance of the C30 1,15-diol relative to the summed abundance of the C28 1,13-, C30 1,13- and C30 1,15-diols. Here we substantially extend and re-evaluate the initial core top calibration by combining the original dataset with 172 data points derived from previously published studies and 262 newly generated data points. In total, we considered 595 globally distributed surface sediments with an enhanced geographical coverage compared to the original calibration. The relationship with SST is similar to that of the original calibration but with considerably increased scatter. The effects of freshwater input (e.g., river runoff) and long-chain diol contribution from Proboscia diatoms on the LDI were evaluated. Exclusion of core-tops deposited at a salinity Proboscia-derived C28 1,12-diol abundance, resulted in a substantial improvement of the relationship between LDI and annual mean SST. This implies that the LDI cannot be directly applied in regions with a strong freshwater influence or high C28 1,12-diol abundance, limiting the applicability of the LDI. The final LDI calibration (LDI = 0.0325 × SST + 0.1082; R2 = 0.88; n = 514) is not statistically different from the original calibration of Rampen et al. (2012) (https://doi.org/10.1016/j.gca.2012.01.024), although with a larger calibration error of 3 °C. This larger calibration error results from several regions where the LDI does not seem to have a strong temperature dependence with annual mean SST, posing a limitation on the application of the LDI
- Published
- 2020
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8. The history of sleep research and sleep medicine in Europe
- Author
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Hartmut Schulz
- Subjects
Europe ,Sleep Wake Disorders ,Behavioral Neuroscience ,Cognitive Neuroscience ,Animals ,Sleep Deprivation ,General Medicine ,Wakefulness ,Sleep ,Circadian Rhythm - Abstract
Sleep became a subject of scientific research in the second half of the 19th century. Since sleep, unlike other physiological functions, cannot be attributed to a specific organ, there was no distinct method available to study sleep until then. With the development of physiology and psychology, and a rapidly increasing knowledge of the structure and functioning of the nervous system, certain aspects of sleep became accessible to objective study. A first step was to measure responsiveness to external stimuli systematically, during sleep, allowing a first representation of the course of sleep (Schlaftiefe = sleep depth). A second method was to register continuously the motor activity across the sleep-wake cycle, which allowed the documentation in detail of rest-activity patterns of monophasic and polyphasic sleep-wake rhythms, or between day or night active animals. The central measurement for sleep research, however, became the electroencephalogram in the 1930s, which allowed observation of the sleeping brain with high temporal resolution. Beside the development of instruments to measure sleep, prolonged sleep deprivation was applied to study physiological and psychological effects of sleep loss. Another input came from clinical and neuropathological observations of patients with pronounced disorders of the sleep-wake cycle, which for the first time allowed localisation of brain areas that are essentially involved in the regulation of sleep and wakefulness. Experimental brain stimulation and lesion studies were carried out with the same aim at this time. Many of these activities came to a halt on the eve of World War II. It was only in the early 1950s, when periods with rapid eye movements during sleep were recognised, that sleep became a research topic of itself. Jouvet and his team explored the brain mechanisms and transmitters of paradoxical sleep, and experimental sleep research became established in all European countries. Sleep medicine evolving simultaneously in different countries, with early centres in Italy and France. In the late 1960s sleep research and chronobiology began to merge. In recent decades, sleep research, dream research, and sleep medicine have benefited greatly from new methods in genetic research and brain imaging techniques. Genes were identified that are involved in the regulation of sleep, circadian rhythms, or sleep disorders. Functional imaging enabled a high spatial resolution of the activity of the sleeping brain, complementing the high temporal resolution of the electroencephalogram.
- Published
- 2022
9. Stable Atlantic Deep Water Mass Sourcing on Glacial‐Interglacial Timescales
- Author
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Hartmut Schulz, Finn Süfke, Patrick Blaser, Jörg Lippold, Marcus Gutjahr, and Frerk Pöppelmeier
- Subjects
010504 meteorology & atmospheric sciences ,530 Physics ,Ocean current ,010502 geochemistry & geophysics ,01 natural sciences ,Deep water ,Geophysics ,Oceanography ,13. Climate action ,550 Earth sciences & geology ,Interglacial ,General Earth and Planetary Sciences ,14. Life underwater ,Glacial period ,Geology ,0105 earth and related environmental sciences - Abstract
Increased deep ocean carbon storage is often invoked as the major sink for lower atmospheric CO2 concentrations during past ice ages. In order to improve the understanding of the changes in ocean dynamics facilitating such increased oceanic carbon storage, we assess the variability of deep water provenance in the Atlantic by reconstructing authigenic Nd isotopes from North Atlantic site U1313 over the past ���100 kyr. Under consideration of these new constraints for the northern Nd isotope end-member, we find only limited long-term variations in the meridional and intra-basin water-mass gradients suggesting a prevalence of northern-sourced water (NSW) throughout the past 100 kyr. Tentative results suggest that during the glacial period of Marine Isotope Stage 4 NSW proportions even increased by additional ���15% in the equatorial and Northeast Atlantic, calling into question the notion that cold climates promote the expansion of southern-sourced water.
- Published
- 2021
- Full Text
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10. Dissimilar behaviors of the geochemical twins W and Mo in hypoxic-euxinic marine basins
- Author
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Bernhard Schnetger, Olaf Dellwig, Helge W Arz, Antje Wegwerth, and Hartmut Schulz
- Subjects
chemistry.chemical_classification ,010504 meteorology & atmospheric sciences ,Sulfide ,Geochemistry ,Sediment ,Sapropel ,Authigenic ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Bottom water ,chemistry.chemical_compound ,Water column ,chemistry ,engineering ,General Earth and Planetary Sciences ,Carbonate ,Pyrite ,0105 earth and related environmental sciences - Abstract
Redox-sensitive trace metals are powerful tools for the reconstruction of modern and past redox conditions in aquatic ecosystems. The most prominent example is molybdenum (Mo), which behaves conservatively as soluble molybdate in the oxygenated ocean, but forms particle-reactive thiomolybdates at sufficiently high sulfide concentrations. Previous studies proposed that the redox behavior of tungsten (W), the geochemical twin of Mo, is also affected by sulfide, suggesting its potential as a promising new redox proxy. Here we present a comprehensive W dataset from the highly sulfidic Black Sea and the weakly sulfidic Landsort Deep (Baltic Sea), as the type localities of modern euxinic basins, that combines water column, pore water, and sediment records. A dataset from the Gotland Basin obtained following oxygenation of the formerly euxinic water column during the major Baltic inflow in 2014 is used as the hypoxic example. The even stronger adsorption of W than Mo on Mn and Fe oxides at pelagic redoxclines identified these particles as important carrier transferring W from the oxygenated surface ocean to euxinic bottom waters. This shuttling was most pronounced during the inflow event in the Gotland Basin causing substantial deposition of Mn oxides that were highly enriched in W. Compared to the oxygenated surface waters, dissolved Mo was severely depleted in the highly sulfidic water column of the Black Sea, whereas the bottom water levels of dissolved W were elevated. An additional W source derived from pore-water reflux, as indicated by the exceptionally high concentrations of W in highly sulfidic pore waters from the Landsort Deep sediments. In addition to the decoupling from Mn, the pore water W enrichments are compatible with the previously proposed greater solubility of thiotungsate species than of tungstate. Despite the absence of a substantial sedimentary accumulation of authigenic W in the sapropels of the Black Sea, the comparable patterns of S, Fe, and W in an Eemian record may suggest sorption of internally cycled (thio)tungstate onto pyrite. Unexpected W enrichments in modern and medieval sediments from the central Landsort Deep indicate a close relationship with Mn carbonate formation occurring during long-lasting bottom water hypoxia. In contrast to the highly variable Mo content, the near-background variation of W in the sapropels of euxinic basins questions the utility of W as a redox proxy in euxinic systems. However, given the strong affinity between W and the Mn/Fe cycle, this element may be a useful proxy in hypoxic systems, especially its isotopic signature.
- Published
- 2019
- Full Text
- View/download PDF
11. Discharges of dust from NORM facilities: Key parameters to assess effective doses for public exposure
- Author
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Jörg Dilling, Eckard Ettenhuber, Astrid Schellenberger, Hartmut Schulz, and Christian Kunze
- Subjects
lcsh:TN1-997 ,Environmental Engineering ,Dose calculation ,Renewable Energy, Sustainability and the Environment ,business.industry ,Radioactive waste ,chemistry.chemical_element ,Geology ,Radon ,Atmospheric dispersion modeling ,Environmental economics ,Safety standards ,Geotechnical Engineering and Engineering Geology ,Directive ,Pollution ,chemistry ,Norm (mathematics) ,Environmental science ,Radiation protection ,business ,lcsh:Mining engineering. Metallurgy - Abstract
In transposing Directive 2013/59/Euratom (European Basic Safety Standards or EU BSS) into national law, it was necessary to identify industrial sectors which involve naturally occurring radioactive materials (NORM) which may lead to public exposure that cannot be disregarded from a radiation protection point of view. A research project was implemented that resulted in a comprehensive survey of all potentially relevant industrial sectors operating in Germany. Major efforts were made to determine source terms of airborne discharges, atmospheric dispersion models, and dose calculations.The study arrived at the conclusion that the discharge and the settlement of dust in agricultural and horticultural areas is the most relevant dispersion and exposure pathway, while discharges of radon are of minor importance.The original study used a number of rather complex models that may distract from the fact that very few key parameters and assumptions determine the effective dose of members of the public. This paper revisits the study and identifies those parameters and assumptions and provides a simplified, generic, yet sufficiently reliable and robust assessment methodology to determine the radiological relevance of dust discharges from NORM industries under the typical geographical and meteorological conditions of Germany.This paper provides examples of dose estimates for members of the public for selected industries operating in Germany. Due to its simplicity and robustness, the methodology can also be used to assess effective doses resulting from discharges in other industries in Germany, and it can be adapted to conditions in other countries in a straightforward way. Keywords: NORM, Dust discharge, Public exposure, High temperature processes, Atmospheric dispersion model
- Published
- 2019
- Full Text
- View/download PDF
12. Geschichten von der großen Stadt Wien - Band 1 : 24 historische Miniaturen vom Anfang bis zu Prinz Eugen
- Author
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Hartmut Schulz, Jessy Schmidt, Hartmut Schulz, and Jessy Schmidt
- Abstract
Das Buch'Geschichten von der großen Stadt Wien, Band 1'erzählt in 24 Miniaturen Episoden aus der Historie Wiens von der Gründung der Stadt durch die Römer bis in die Zeit Prinz Eugens. Um die fiktionalen Geschichten besser einordnen zu können, verbinden kurze historische Erläuterungen die einzelnen Episoden. So entsteht ein abwechslungsreicher Führer durch 1.500 Jahre Geschichte Wiens, der Literatur-Freunde ebenso anspricht wie historisch interessierte Besucher der Donaumetropole.
- Published
- 2023
13. Submerged landscapes of the eastern Adriatic – from the river across the lake all the way to the sea
- Author
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Slobodan Miko, Petra Bajo, Koraljka Bakrač, Dea Brunović, Dimitris Christodoulou, Tatjana Durn, Maria Geraga, Valentina Hajek-Tadesse, Ozren Hasan, Dario Hruševar, Nikolina Ilijanić, Ivor Karavanić, Saša Mesić, Božena Mitić, George Papatheodorou, Branko Petrinec, Ana Prohaska, Irena Radić Rossi, Ivan Razum, Hartmut Schulz, Natalia Šenolt, Martina Šparica Miko, Eske Willerslev
- Subjects
eastern Adriatic coast, submerged landscapes, Krka River - Abstract
Submerged paleolandscapes constitute records of long-term paleoenvironmental change, climate, and sea level. To date, there is a very limited knowledge concerning the submerged karst paleolandscapes of the eastern Adriatic coast and the Late Quaternary sedimentary sequences along the eastern part of the Mid Adriatic Deep (MAD). We aim to improve this through the project “Sediments between source and sink during a Late Quaternary eustatic cycle: The Krka and the Mid Adriatic Deep System” (QMAD). The QMAD project supports multidisciplinary research by application of the high-resolution geophysical surveys (multibeam, side-scan sonar and sub-bottom profiler), in combination with sedimentological, petrophysical, geochemical (trace elements and isotopes), micropaleontological (ostracod and foraminifera), mineralogical and aDNA techniques. This suite of analyses will enable tracking of the paleoenvironmental evolution from fluvial/lake to deeper marine environments, on a short transect less than 100 km in length (Lake Prokljan in the Krka River estuary to the eastern part of MAD). The submerged Late Pleistocene and Holocene environments that occur include isolation basins, lagoons, deltas, estuaries, submarine channels and shelf. The continuous marine sedimentation during the Late Quaternary is investigated in the MAD. In the case of the central part of the eastern side of the Adriatic Sea (Krka catchment - MAD) these different environments compose an integrated system ; thus, they can’t be analysed separately. The main goals of this project fill the existing gaps in understanding of the climatic and environmental changes, including sea-level related landscape changes and their interplay during the Late Quaternary eustatic cycle. More data on the Pleistocene environments, especially from the region of Krka estuary that was land during the Last Glacial Maximum (LGM), will complete the picture of the evolution and environmental adaptation of Paleolithic humans and their relationship with vegetation changes. Attention is also paid to potential anthropogenic environments, recent sedimentation rates, landscape features and artefacts. All results of the multi-proxy approach applied in this project will eventually be merged into a comprehensive Late Quaternary paleoenvironmental and paleoclimatic reconstruction of the eastern Adriatic landscapes that contribute to the understanding of these changes in the Mediterranean region.
- Published
- 2021
14. Schlafwahrnehmung
- Author
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Hartmut Schulz
- Published
- 2021
- Full Text
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15. Comparison of Holocene and Last Interglacial sapropels in the Gulf of Sirte (eastern Mediterranean)
- Author
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Kazuyo Tachikawa, Laurence Vidal, José N. Pérez-Asensio, Marta Garcia, Adnya Pratiwi, and Hartmut Schulz
- Abstract
The Mediterranean thermohaline circulation is sensitive to ongoing climate change and generally stagnant circulation is expected by the end of the 21st century. In the past, the eastern Mediterranean Sea has experienced slower ventilation as demonstrated by rhythmic occurrence of organic-rich sediments “sapropels”. The two sapropels S1 (Holocene) and S5 (Last Interglacial) were formed under conditions of excess fresh water inputs via Nile river in relation to insolation-driven African monsoon intensification and deglacial meltwater inputs from the North Atlantic. In addition to the Nile river discharge, the paleodrainage toward Gulf of Sirte off Libya has been proposed although its contribution could be significantly different between S1 and S5 because of distinct monsoon intensification. Since the response of circulation to freshwater forcing could vary with the region of perturbation, comparison of S1 and S5 deposited in the Gulf of Sirte will provide key information on the Mediterranean ventilation sensitivity.We applied a multi-proxy approach (bulk elemental composition by XRF scanning, redox sensitive elemental concentration, planktonic foraminiferal δ18O and benthic foraminiferal faunal assemblages) to core SL95 (32º46.46N, 19º11.46E; 1390 m water depth) from the eastern side of the Gulf of Sirte. Both S1 and S5 are marked by prominent peaks of Ba/Al and Ba/Ti with more pronounced Ba enrichment for S5. Redox sensitive elements such as U and Mo present enrichment prior to the Ba peaks that can be interpreted as reduced ventilation before sapropel deposition. However, expected reduced oxygenation is not synchronous with benthic foraminiferal faunal changes, suggesting possible remobilisation of the trace elements during sapropel interruption and/or post-sapropel oxygenation. Acquisition of high-temporal resolution data of Globigerinoides ruber δ18O and benthic foraminiferal assemblages is in progress. We will discuss potential influence of (partial) ventilation at intermediate water depths during sapropel interruption in association with 8.2 event and possible different freshwater inputs at S1 and S5 depositions.
- Published
- 2020
- Full Text
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16. UAV-based mapping of radioactive contamination of uranium mining legacies in Central Asia
- Author
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Sven Altfelder, Robert Arndt, Malte Ibs-von Seht, Christian Kunze, Benedikt Preugschat, Marius Schröder, Hartmut Schulz, and Benjamin Wiens
- Abstract
In the Central Asian countries of Kyrgyzstan, Tajikistan, Uzbekistan and Kazakhstan, uranium production activities during the Soviet era have led to a large number of mining legacies. The mining residues can show significant levels of radioactive contamination. Due to the mountainous landscape and the geotechnical conditions at these sites, there is a risk of uncontrolled release of radioactive contaminants into the environment and into cross-border rivers in the region. The situation is exacerbated further by the fact that the countries are prone to natural hazards such as earthquakes, floods, mudflows and landslides. There is an urgent need to map locations, extent and inventory of the contaminated areas in order to be able to support remediation measures and monitor the long-term stability of the remediated legacies.The research project DUB-GEM funded by the German Federal Ministry of Education and Research (grant no. 01LZ106A-C) deals with the development of a UAV-based gamma spectrometry for the exploration and monitoring of uranium mining legacies. The aim of the three-year project is to develop and apply a method that allows regulatory authorities and operators to map contaminated sites rapidly and economically using gamma spectrometers mounted on a UAV (unmanned aerial vehicle). The main tasks of the project are to select and configure suitable detectors, to develop flight, measurement, and data processing strategies and to design an airframe that is ideally suited to carry out the surveys. In this contribution we present the current status of the project, including the design of the UAV prototype, results of the first test and calibration measurements with the selected gamma spectrometers and an outlook on upcoming project activities.
- Published
- 2020
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17. Detection and Characterisation of Eemian Marine Tephra Layers within the Sapropel S5 Sediments of the Aegean and Levantine Seas
- Author
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Ian Matthews, Katharine M. Grant, J. John Lowe, Sabine Wulf, Hartmut Schulz, Christopher Satow, and Addison Mallon
- Subjects
eemian ,Provenance ,010504 meteorology & atmospheric sciences ,NERC ,lcsh:GN281-289 ,Eemian ,010502 geochemistry & geophysics ,01 natural sciences ,palaeoceanography ,Paleontology ,lcsh:Stratigraphy ,Earth and Planetary Sciences (miscellaneous) ,Tephra ,tephrochronology ,lcsh:QE640-699 ,0105 earth and related environmental sciences ,Earth-Surface Processes ,geography ,geography.geographical_feature_category ,quaternary ,RCUK ,Europe ,sedimentology-marine cores ,Sapropel ,Volcano ,Interglacial ,lcsh:Human evolution ,NE/E015905/1 ,europe ,Quaternary ,Tephrochronology ,Geology - Abstract
The Eemian was the last interglacial period (~130 to 115 ka BP) to precede the current interglacial. In Eastern Mediterranean marine sediments, it is marked by a well-developed and organic-rich “sapropel” layer (S5), which is thought to reflect an intensification and northward migration of the African monsoon rain belt over orbital timescales. However, despite the importance of these sediments, very little proxy-independent stratigraphic information is available to enable rigorous correlation of these sediments across the region. This paper presents the first detailed study of visible and non-visible (cryptotephra) layers found within these sediments at three marine coring sites: ODP Site 967B (Levantine Basin), KL51 (South East of Crete) and LC21 (Southern Aegean Sea). Major element analyses of the glass component were used to distinguish four distinct tephra events of Santorini (e.g., Vourvoulos eruption) and possible Anatolian provenance occurring during the formation of S5. Interpolation of core chronologies provides provisional eruption ages for the uppermost tephra (unknown Santorini, 121.8 ± 2.9 ka) and lowermost tephra (Anatolia or Kos/Yali/Nisyros, 126.4 ± 2.9 ka). These newly characterised tephra deposits have also been set into the regional tephrostratigraphy to illustrate the potential to precisely synchronise marine proxy records with their terrestrial counterparts, and also contribute to the establishment of a more detailed volcanic history of the Eastern Mediterranean.
- Published
- 2020
- Full Text
- View/download PDF
18. Intra-Night Sleep Perception in Patients with Sleep Disorders
- Author
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Björn W. Walther and Hartmut Schulz
- Subjects
Sleep disorder ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Epworth Sleepiness Scale ,Polysomnography ,Audiology ,medicine.disease ,Non-rapid eye movement sleep ,Sleep in non-human animals ,Sleep medicine ,Psychiatry and Mental health ,Neurology ,Sleep debt ,medicine ,Insomnia ,Neurology (clinical) ,medicine.symptom ,business ,psychological phenomena and processes - Abstract
Measured and rated sleep differ in normal sleepers and even more in patients with sleep disorders. The study aimed to asses sleep/wake perception in electrophysiologically defined sleep in patients with sleep disorders. 117 consecutively referred patients (75 females), median age 50.3 years, range 20–73 years) with various sleep disorders were randomized for one induced waking, either out of stage 2 (S2) or REM sleep, as part of a clinical routine polysomnography. Patients were classified as either non-sleepy (Epworth Sleepiness Scale score ESS ≤ 10) or sleepy (ESS ≥ 11). The most frequent diagnoses of non-sleepy patients were insomnia and RLS, while sleepy patients suffered predominantly from OSAS, hypersomnia and insufficient sleep syndrome. Subjects were deliberately aroused once, either out of consolidated stage 2 sleep (n = 66) or REM sleep (n = 51) and asked for sleep/wake perception (sleep/wake and related questions). While 81 (69.2%) of the subjects estimated that they had been sleeping or dozing before they were aroused, 36 (30.8%) reported that they had been awake. Awake ratings were significantly more frequent for S 2 (45.5%) than for REM sleep (11.8%). The difference between sleep states was most pronounced for insomniacs (58.1% awake ratings in S2 vs. 5.3% in REM sleep). Mismatches between measured sleep and perceived state are quite frequent, with a greater disparity for S2 than for REM sleep, especially in insomniac patients. We suggest that state judgement is contingent not only on the state of the sleep regulating system but also on cognitive processes associated with processing of external and internal stimuli, and dreaming.
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- 2017
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19. The C32 alkane-1,15-diol as a proxy of late Quaternary riverine input in coastal margins
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Isla S. Castañeda, Enno Schefuß, Jaap S. Sinninghe Damsté, Denise J C Dorhout, Julie Lattaud, Stefan Schouten, and Hartmut Schulz
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chemistry.chemical_classification ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Stratigraphy ,Paleontology ,Sediment ,15. Life on land ,010502 geochemistry & geophysics ,01 natural sciences ,Proxy (climate) ,Indian ocean ,Oceanography ,chemistry ,13. Climate action ,River mouth ,Organic matter ,Sedimentary rock ,14. Life underwater ,Quaternary ,Surface runoff ,Geology ,0105 earth and related environmental sciences - Abstract
The study of past sedimentary records from coastal margins allows us to reconstruct variations in terrestrial input into the marine realm and to gain insight into continental climatic variability. There are numerous organic proxies for tracing terrestrial input into marine environments but none that strictly reflect the input of river-produced organic matter. Here, we test the fractional abundance of the C32 alkane 1,15-diol relative to all 1,13- and 1,15-long-chain diols (FC32 1, 15) as a tracer of input of river-produced organic matter in the marine realm in surface and Quaternary (0–45 ka) sediments on the shelf off the Zambezi and nearby smaller rivers in the Mozambique Channel (western Indian Ocean). A Quaternary (0–22 ka) sediment record off the Nile River mouth in the eastern Mediterranean was also studied for long-chain diols. For the Mozambique Channel, surface sediments of sites most proximal to Mozambique rivers showed the highest F1, 15 − C32 (up to 10 %). The sedimentary record shows high (15–35 %) pre-Holocene F1, 15 − C32 and low (
- Published
- 2017
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20. Inverse response of 231Pa/230Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water
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Sönke Szidat, Marcel Regelous, Thomas F. Stocker, Finn Süfke, Hartmut Schulz, Tyler J. Goepfert, Jeemijn Scheen, Patrick Blaser, Frerk Pöppelmeier, and Jörg Lippold
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Atlantic hurricane ,010504 meteorology & atmospheric sciences ,Ocean current ,Sediment ,Last Glacial Maximum ,Environmental Science (miscellaneous) ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,Oceanography ,01 natural sciences ,13. Climate action ,Earth and Planetary Sciences (miscellaneous) ,Sedimentary rock ,14. Life underwater ,Glacial period ,Stadial ,Geology ,Holocene ,0105 earth and related environmental sciences - Abstract
This study aims to provide a more detailed understanding of the behavior of 231Pa/230Th under varying ocean circulation regimes. The North Atlantic provides a unique sedimentary setting with its ice-rafted detritus (IRD) layers deposited during glacial times. These layers have been found north of 40° N (Ruddiman Belt) and are most pronounced during Heinrich Stadials. Most of these sediments have been recovered from the deep North Atlantic basin typically below 3000 m water depth. This study reports sedimentological and sediment geochemical data from one of the few sites at intermediate depth of the open North Atlantic (core SU90-I02, 45° N 39° W, 1965 m water depth) within the Ruddiman Belt. The time periods of Heinrich Stadials 1 and 2 of this core were identified with the help of the major element composition by XRF scanning and by IRD counting. Along the core profile, the sedimentary 231Pa/230Th activity ratio has been measured as a kinematic proxy for the circulation strength. The 231Pa/230Th record shows highest values during the Holocene and Last Glacial Maximum, above the natural production ratio of these isotopes. During Heinrich Stadials 1 and 2, when Atlantic meridional overturning circulation was most reduced, the 231Pa/230Th record shows overall lowest values below the production ratio. This behavior is contrary to classical findings of 231Pa/230Th from the northwestern Atlantic where a strong Holocene circulation is associated with low values. However, this behavior at the presented location is in agreement with results from simulations of the 231Pa/230Th-enabled Bern3D Earth system model.
- Published
- 2020
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21. Geschichte der Schlafmedizin
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Hartmut Schulz
- Published
- 2020
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22. Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand
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Eirik Vinje Galaasen, Helga F Kleiven, Eelco J. Rohling, Yair Rosenthal, Katharine M. Grant, Gianluca Marino, Andrew P. Roberts, Fiona D. Hibbert, Felicity Williams, Nil Irvali, Hartmut Schulz, Jimin Yu, and Ulysses S Ninnemann
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010504 meteorology & atmospheric sciences ,Science ,General Physics and Astronomy ,Antarctic ice sheet ,Greenland ice sheet ,010502 geochemistry & geophysics ,Palaeoclimate ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Article ,Palaeoceanography ,lcsh:Science ,Sea level ,0105 earth and related environmental sciences ,High rate ,geography ,Multidisciplinary ,geography.geographical_feature_category ,2508.07 Hielo ,General Chemistry ,2508.03 Glaciología ,Sea level rise ,2510 Oceanografía ,Interglacial ,lcsh:Q ,Physical geography ,Ice sheet ,Geology - Abstract
The last interglacial (LIG; ~130 to ~118 thousand years ago, ka) was the last time global sea level rose well above the present level. Greenland Ice Sheet (GrIS) contributions were insufficient to explain the highstand, so that substantial Antarctic Ice Sheet (AIS) reduction is implied. However, the nature and drivers of GrIS and AIS reductions remain enigmatic, even though they may be critical for understanding future sea-level rise. Here we complement existing records with new data, and reveal that the LIG contained an AIS-derived highstand from ~129.5 to ~125 ka, a lowstand centred on 125–124 ka, and joint AIS + GrIS contributions from ~123.5 to ~118 ka. Moreover, a dual substructure within the first highstand suggests temporal variability in the AIS contributions. Implied rates of sea-level rise are high (up to several meters per century; m c−1), and lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations., The relative contributions of the Greenland and Antarctic Ice Sheets to Last Interglacial sea level rise remain debated, as do the timing and magnitude. Here, data show that the Antarctic Ice Sheet dominated particularly high levels of sea-level rise during the early Last Interglacial.
- Published
- 2019
23. Supplementary material to 'Calcification and distribution of extant coccolithophores across the Drake Passage during late austral summer 2016'
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Mariem Saavedra-Pellitero, Karl-Heinz Baumann, Miguel Ángel Fuertes, Hartmut Schulz, Yann Marcon, Nele Manon Vollmar, José-Abel Flores, and Frank Lamy
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- 2019
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24. Calcification and distribution of extant coccolithophores across the Drake Passage during late austral summer 2016
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Mariem Saavedra-Pellitero, Karl-Heinz Baumann, Miguel Ángel Fuertes, Hartmut Schulz, Yann Marcon, Nele Manon Vollmar, José-Abel Flores, and Frank Lamy
- Abstract
Coccolithophores are globally distributed microscopic marine algae that exert a major influence on the global carbon cycle through calcification and primary productivity. There is recent interest in coccolithophore polar communities, however field observations regarding their biogeographic distribution are scarce for the Southern Ocean. This study documents the latitudinal variability in the coccolithophore assemblage composition and the coccolith mass variation of the ecologically dominant Emiliania huxleyi across the Drake Passage. Ninety-six water samples were taken between 10 and 150 m water depth from 18 stations during POLARSTERN Expedition PS97 (February–April, 2016). A minimum of 200 coccospheres per sample were classified in scanning electron microscope and coccolith mass was estimated with light microscopy, using the C-Calcita software. We find that coccolithophore abundance and diversity decrease southwards marking different oceanographic fronts as ecological boundaries. We characterize three zones: (1) the Chilean margin, where E. huxleyi type A (normal and overcalcified) and type R are present; (2) the Subantarctic Zone (SAZ), where E. huxleyi reaches maximum values of 212.5×103cells/L and types B/C, C, O are dominant. (3) The Polar Front Zone (PFZ), where E. huxleyi types B/C and C dominate. We link the decreasing trend in E. huxleyi coccolith mass to the poleward latitudinal succesion from type A to type B group. Remarkably, we find that coccolith mass is strongly anticorrelated to total alkalinity, total CO2, bicarbonate ion and pH. We speculate that low temperatures are a greater limiting factor than carbonate chemistry in the Southern Ocean. However, further in situ oceanographical data is needed to verify the proposed relationships. We hypothesize that assemblage composition and calcification modes of E. huxleyi in the Drake Passage will be strongly influenced by the ongoing climate change.
- Published
- 2019
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25. Wann und wie viel wir schlafen sollen
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Hartmut Schulz
- Subjects
General Medicine - Abstract
Veränderungen der Lebensgewohnheiten und des Schlafverhaltens als Folge von technischen Neuerungen sind gut dokumentiert. Die heutige Diskussion kreist um die 24/7-Gesellschaft: 24 Stunden erreichbar sein und das an allen sieben Tagen der Woche, rund um den Globus.
- Published
- 2017
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26. The Indian winter monsoon and its response to external forcing over the last two and a half centuries
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Michael Siccha, Hartmut Schulz, Sven Forke, Michal Kucera, Philipp Munz, Andreas Lückge, and Anna Böll
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Northern Hemisphere ,Tropics ,010502 geochemistry & geophysics ,Monsoon ,01 natural sciences ,Oceanography ,Geography ,North Atlantic oscillation ,Climatology ,Tropical monsoon climate ,Extratropical cyclone ,Pacific decadal oscillation ,0105 earth and related environmental sciences ,Teleconnection - Abstract
The Indian winter monsoon (IWM) is a key component of the seasonally changing monsoon system that affects the densely populated regions of South Asia. Cold winds originating in high northern latitudes provide a link of continental-scale Northern Hemisphere climate to the tropics. Western disturbances associated with the IWM play a critical role for the climate and hydrology in northern India and the western Himalaya region. It is vital to understand the mechanisms and teleconnections that influence IWM variability to better predict changes in future climate. Here we present a study of regionally calibrated winter (January) temperatures and according IWM intensities, based on a planktic foraminiferal record with biennial (2.55 years) resolution. Over the last ~250 years, IWM intensities gradually weakened, based on the long-term trend of reconstructed January temperatures. Furthermore, the results indicate that IWM is connected on interannual- to decadal time scales to climate variability of the tropical and extratropical Pacific, via El Nino Southern Oscillation and Pacific Decadal Oscillation. However, our findings suggest that this relationship appeared to begin to decouple since the beginning of the twentieth century. Cross-spectral analysis revealed that several distinct decadal-scale phases of colder climate and accordingly more intense winter monsoon centered at the years ~1800, ~1890 and ~1930 can be linked to changes of the North Atlantic Oscillation.
- Published
- 2016
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27. The Development of Sleep Medicine: A Historical Sketch
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Hartmut Schulz and Piero Salzarulo
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Sleep Wake Disorders ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Alternative medicine ,Sleep medicine ,03 medical and health sciences ,0302 clinical medicine ,mental disorders ,medicine ,Insomnia ,Humans ,Psychiatry ,Review Articles ,Sleep Medicine Specialty ,Scope (project management) ,Traditional medicine ,business.industry ,Sleep apnea ,Parasomnia ,medicine.disease ,Sleep in non-human animals ,030228 respiratory system ,Neurology ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Narcolepsy - Abstract
For centuries the scope of sleep disorders in medical writings was limited to those disturbances which were either perceived by the sleeper him- or herself as troublesome, such as insomnia, or which were recognized by an observer as strange behavioral acts during sleep, such as sleepwalking or sleep terrors. Awareness of other sleep disorders, which are caused by malfunction of a physiological system during sleep, such as sleep-related respiratory disorders, were widely unknown or ignored before sleep monitoring techniques became available, mainly in the second half of the 20(th) century. Finally, circadian sleep-wake disorders were recognized as a group of disturbances by its own only when chronobiology and sleep research began to interact extensively in the last two decades of the 20(th) century. Sleep medicine as a medical specialty with its own diagnostic procedures and therapeutic strategies could be established only when key findings in neurophysiology and basic sleep research allowed a breakthrough in the understanding of the sleeping brain, mainly since the second half of the last century.
- Published
- 2016
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28. A distal 140 kyr sediment record of Nile discharge and East African monsoon variability
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Hartmut Schulz, Gerhard Schmiedl, Stefan Krüger, Martin Seidel, and Werner Ehrmann
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010506 paleontology ,010504 meteorology & atmospheric sciences ,Stratigraphy ,lcsh:Environmental protection ,Monsoon ,01 natural sciences ,Mediterranean sea ,lcsh:Environmental pollution ,lcsh:TD169-171.8 ,14. Life underwater ,Stadial ,Glacial period ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,Hydrology ,lcsh:GE1-350 ,Global and Planetary Change ,Paleontology ,Sediment ,Sahara pump theory ,Oceanography ,13. Climate action ,lcsh:TD172-193.5 ,Sedimentary rock ,Quaternary ,Geology - Abstract
Clay mineral assemblages in a sediment core from the distal Nile discharge plume off Israel have been used to reconstruct the late Quaternary Nile sediment discharge into the eastern Mediterranean Sea (EMS). The record spans the last ca. 140 kyr. Smectite abundances indicate the influence of the Blue Nile and the Atbara River that have their headwaters in the volcanic rocks of the Ethiopian Highlands. Kaolinite abundances indicate the influence of wadis, which contribute periodically to the suspension load of the Nile. Due to the geographical position, the climate and the sedimentary framework of the EMS is controlled by two climate systems. The long-term climate regime was governed by the African monsoon that caused major African humid periods (AHPs) with enhanced sediment discharge at 132 to 2 kyr), S4 (3.5 kyr), and S3 (5 kyr). During the last glacial period (Marine Isotope Stages (MISs) 4–2), the long-term changes in the monsoonal system were superimposed by millennial-scale changes in an intensified midlatitude glacial system. This climate regime caused short but pronounced drought periods in the Nile catchment, which are linked to Heinrich events and alternate with more humid interstadials. The clay mineral record further implies that feedback mechanisms between vegetation cover and sediment discharge of the Nile are detectable but of minor importance for the sedimentary record in the southeastern Mediterranean Sea during the investigated African humid periods.
- Published
- 2016
29. Fatal Agranulocytosis Associated With Quetiapine in Monotherapy
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Hartmut Schulz, Catherine Glocker, and Renate Grohmann
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Pediatrics ,medicine.medical_specialty ,Fatal outcome ,business.industry ,medicine.disease ,030227 psychiatry ,03 medical and health sciences ,Psychiatry and Mental health ,0302 clinical medicine ,Schizophrenia ,Quetiapine Fumarate ,medicine ,Quetiapine ,Pharmacology (medical) ,Young adult ,business ,030217 neurology & neurosurgery ,medicine.drug - Published
- 2017
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30. The resilience and sensitivity of Northeast Atlantic deep water εNd to overprinting by detrital fluxes over the past 30,000 years
- Author
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Marcus Gutjahr, Jasmin M. Link, Norbert Frank, Jörg Lippold, Juliane Hoffmann, Frerk Pöppelmeier, Hartmut Schulz, Sönke Szidat, Martin Frank, Patrick Blaser, and H. Heinrich
- Subjects
Marine isotope stage ,Provenance ,Water mass ,010504 meteorology & atmospheric sciences ,North Atlantic Deep Water ,Geochemistry ,Labrador Sea Water ,010502 geochemistry & geophysics ,01 natural sciences ,Bottom water ,Antarctic Bottom Water ,13. Climate action ,Geochemistry and Petrology ,14. Life underwater ,Geology ,0105 earth and related environmental sciences ,Ice rafting - Abstract
The neodymium isotope proxy has become a valuable tool for the reconstruction of past ocean water mass provenance and mixing. For its accurate application, knowledge about the origin and preservation of Nd in sedimentary archives is crucial. Recently, concerns have emerged regarding the applicability of neodymium isotopes as a conservative palaeo water mass tracer, given potential Nd fluxes from sediments into bottom waters (Abbott et al., 2015a) and inferred relabelling of ocean waters by settling detrital material (Roberts and Piotrowski, 2015). Consequently, a decoupling of water mass provenance and proxy variations may arise. We investigate the mobility of Nd around extreme detrital sedimentation events such as glacial ice rafting pulses and turbidite deposition in the Northeast Atlantic. The constructed records from sediment leachates span extreme Nd isotope variations including volcanic (eNd ∼ 0) and Laurentian (eNd ∼ −27) sources. We find that Nd was released into pore waters from reactive detritus inside some detrital layers during early diagenesis, thereby overprinting any archived bottom water Nd signature and precluding the reconstruction of past water mass provenance during the affected time intervals. However, we do not observe any definite indication of diffusive vertical migration of Nd into adjacent layers. Furthermore, bottom water Nd isotope signatures were not modified to a measurable degree by any potential benthic flux of Nd during the deposition of these detrital sediment layers. Consequently, the Nd isotope composition of the pelagic glacial Northeast Atlantic water masses were resilient to such episodic large detrital fluxes. Apart from extreme local sedimentation events, we confirm the presence of detritally overprinted deep waters north of 47°N during the peak glacial from comparison of Northeast Atlantic depth transects. We furthermore suggest that the sensitivity of deep waters to this overprinting effect increased during periods of reduced Atlantic Meridional Overturning Circulation and elevated ice rafting. Overall, our study demonstrates that a thorough evaluation of the proportion of Nd originating from physical water mass advection versus in situ chemical inputs is crucial for the reliable application of Nd isotopes as a water mass tracer.
- Published
- 2019
31. Advancing Santorini’s tephrostratigraphy: new glass geochemical data and improved marine-terrestrial tephra correlations for the past ∼360 kyrs
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Hartmut Schulz, Polina S Vakhrameeva, Sabine Wulf, Jörg Keller, Christopher Satow, M. Kraml, Mark Hardiman, Oona Appelt, Andreas Koutsodendris, Ralf Gertisser, Jörg Pross, and Katharine M. Grant
- Subjects
geography ,GB ,Explosive eruption ,geography.geographical_feature_category ,Santorini ,010504 meteorology & atmospheric sciences ,Eastern Mediterranean region ,Sapropel ,010502 geochemistry & geophysics ,01 natural sciences ,Paleontology ,Eastern mediterranean ,Volcano ,Pumice ,Land-sea correlations ,General Earth and Planetary Sciences ,EPMA glass chemistry ,14. Life underwater ,Tephra ,Geology ,Proximal tephra deposits ,Marine tephrostratigraphy ,0105 earth and related environmental sciences - Abstract
The island of Santorini in the Aegean Sea is one of the world’s most violent active volcanoes. Santorini has produced numerous highly explosive eruptions over at least the past ∼360 kyrs that are documented by the island’s unique proximal tephra record. However, the lack of precise eruption ages and comprehensive glass geochemical datasets for proximal tephras has long hindered the development of a detailed distal tephrostratigraphy for Santorini eruptions. In light of these requirements, this study develops a distal tephrostratigraphy for Santorini covering the past ∼360 kyrs, which represents a major step forward towards the establishment of a tephrostratigraphic framework for the Eastern Mediterranean region. We present new EPMA glass geochemical data of proximal tephra deposits from twelve Plinian and numerous Inter-Plinian Santorini eruptions and use this dataset to establish assignments of 28 distal marine tephras from three Aegean Sea cores (KL49, KL51 and LC21) to specific volcanic events. Based on interpolation of sapropel core chronologies we provide new eruption age estimates for correlated Santorini tephras, including dates for major Plinian eruptions, Upper Scoriae 1 (80.8 ± 2.9 ka), Vourvoulos (126.5 ± 2.9 ka), Middle Pumice (141.0 ± 2.6 ka), Cape Thera (156.9 ± 2.3 ka), Lower Pumice 2 (176.7 ± 0.6 ka), Lower Pumice 1 (185.7 ± 0.7 ka), and Cape Therma 3 (200.2 ± 0.9 ka), but also for 17 Inter-Plinian events. Older Plinian and Inter-Plinian activity between ∼310 ka and 370 ka, documented in the distal terrestrial setting of Tenaghi Philippon (NE Greece), is independently dated by palynostratigraphy and complements the distal Santorini tephrostratigraphic record.
- Published
- 2019
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32. Vertical and lateral flux on the continental slope off Pakistan: correlation of sediment core and trap results
- Author
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U. von Rad and Hartmut Schulz
- Subjects
geography ,Varve ,geography.geographical_feature_category ,Continental shelf ,lcsh:QE1-996.5 ,lcsh:Life ,Sediment ,Sediment trap (geology) ,Silt ,Oxygen minimum zone ,lcsh:Geology ,lcsh:QH501-531 ,lcsh:QH540-549.5 ,lcsh:Ecology ,Transect ,Geomorphology ,Bioturbation ,Ecology, Evolution, Behavior and Systematics ,Geology ,Earth-Surface Processes - Abstract
Due to the lack of bioturbation, the varve-laminated muds from the oxygen minimum zone (OMZ) off Pakistan provide a unique opportunity to precisely determine the vertical and lateral sediment fluxes in the nearshore part of the northeastern Arabian Sea. West of Karachi (Hab area), the results of two sediment trap stations (EPT and WPT) were correlated with 16 short sediment cores on a depth transect crossing the OMZ. The top of a distinct, either reddish- or light-gray silt layer, 210Pb-dated as AD 1905 ± 10, was used as an isochronous stratigraphic marker bed to calculate sediment accumulation rates. In one core, the red and gray layer were separated by a few (5–10) thin laminae. According to our varve model, this contributes < 10 years to the dating uncertainty, assuming that the different layers are almost synchronous. We directly compared the accumulation rates with the flux rates from the sediment traps that collected the settling material within the water column above. All traps on the steep Makran continental slope show exceptionally high, pulsed winter fluxes of up to 5000 mg m−2 d−1. Based on core results, the flux at the seafloor amounts to 4000 mg m−2 d−1 and agrees remarkably well with the bulk winter flux of material, as well as with the flux of the individual bulk components of organic carbon, calcium carbonate and opal. However, due to the extreme mass of remobilized matter, the high winter flux events exceeded the capacity of the shallow traps. Based on our comparisons, we argue that high-flux events must occur regularly during winter within the upper OMZ off Pakistan to explain the high accumulations rates. These show distribution patterns that are a negative function of water depth and distance from the shelf. Some of the sediment fractions show marked shifts in accumulation rates near the lower boundary of the OMZ. For instance, the flux of benthic foraminifera is lowered but stable below ~1200–1300 m. However, flux and sedimentation in the upper eastern Makran area are dominated by the large amount of laterally advected fine-grained material and by the pulsed nature of the resuspension events at the upper margin during winter.
- Published
- 2018
33. Decadal-resolution record of winter monsoon intensity over the last two millennia from planktic foraminiferal assemblages in the northeastern Arabian Sea
- Author
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Andreas Lückge, Michael Siccha, Anna Böll, Philipp Munz, Michal Kucera, and Hartmut Schulz
- Subjects
Monsoon of South Asia ,Archeology ,Global and Planetary Change ,Sea surface temperature ,Indian ocean ,Oceanography ,Ecology ,Winter monsoon ,Climatology ,Paleontology ,Precipitation ,Geology ,Earth-Surface Processes - Abstract
The Indian monsoon system is an important climate feature of the northern Indian Ocean. Small variations of the wind and precipitation patterns have fundamental influence on the societal, agricultural, and economic development of India and its neighboring countries. To understand current trends, sensitivity to forcing, or natural variation, records beyond the instrumental period are needed. However, high-resolution archives of past winter monsoon variability are scarce. One potential archive of such records are marine sediments deposited on the continental slope in the NE Arabian Sea, an area where present-day conditions are dominated by the winter monsoon. In this region, winter monsoon conditions lead to distinctive changes in surface water properties, affecting marine plankton communities that are deposited in the sediment. Using planktic foraminifera as a sensitive and well-preserved plankton group, we first characterize the response of their species distribution on environmental gradients from a dataset of surface sediment samples in the tropical and sub-tropical Indian Ocean. Transfer functions for quantitative paleoenvironmental reconstructions were applied to a decadal-scale record of assemblage counts from the Pakistan Margin spanning the last 2000 years. The reconstructed temperature record reveals an intensification of winter monsoon intensity near the year 100 CE. Prior to this transition, winter temperatures were >1.5°C warmer than today. Conditions similar to the present seem to have established after 450 CE, interrupted by a singular event near 950 CE with warmer temperatures and accordingly weak winter monsoon. Frequency analysis revealed significant 75-, 40-, and 37-year cycles, which are known from decadal- to centennial-scale resolution records of Indian summer monsoon variability and interpreted as solar irradiance forcing. Our first independent record of Indian winter monsoon activity confirms that winter and summer monsoons were modulated on the same frequency bands and thus indicates that both monsoon systems are likely controlled by the same driving force.
- Published
- 2015
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34. Internationale Klassifikation der Schlafstörungen: Übersicht über die Änderungen in der ICSD-3
- Author
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Peter Geisler, Andrea Rodenbeck, Geert Mayer, and Hartmut Schulz
- Subjects
Gynecology ,medicine.medical_specialty ,business.industry ,Physiology (medical) ,Medicine ,business - Abstract
Der folgende Artikel gibt einen zusammenfassenden Uberblick (fur die schlafbezogenen Atmungsstorungen siehe den Artikel von Stuck und Wees in diesem Heft) uber die Anderungen der 2014 publizierten dritten Auflage der Internationalen Klassifikation von Schlafstorungen (International Classification of Sleep Disorders, ICSD-3) im Vergleich zur Vorgangerversion (ICSD-2 von 2005). Fur Schlafregistrierungen und Auswertungen im Rahmen der Diagnostik gelten die Kriterien der jeweils aktuellen Version des AASM-Manuals. Bei den Insomnien wird jetzt nur noch zwischen chronischen und Kurzzeit-Insomnien unterschieden. Die chronische Insomnie umfasst alle fruheren Insomnieformen mit Ausnahme der anpassungsbedingten (akuten) Insomnie. Als Mindestdauer fur die chronische Insomnie werden jetzt drei Monate verlangt. Der nicht erholsame Schlaf wird nicht mehr als Insomnie-spezifisches Einzelsymptom gelistet. Der bisherige Uberbegriff „Hypersomnien zentralnervosen Ursprungs“ wurde in „Zentrale Storungen mit Tagesschlafrigkeit“ (im Original: Central Disorders of Hypersomnolence) umbenannt. Die Narkolepsie mit Kataplexien oder mit Hypocretin-1-Defizit wird als Narkolepsie Typ 1 bezeichnet, die Narkolepsie ohne Kataplexien als Typ 2. Die Kriterien fur zirkadiane Schlaf-Wach-Rhythmusstorungen wurden kaum verandert. Die NREM-Parasomnien umfassen nun die Arousalstorungen und die schlafbezogene Essstorung. Der Begriff „Schlaftrunkenheit“ wurde aus der Kategorie confusional arousal entfernt, sodass nun „verwirrtes Erwachen“ klassifiziert wird. Die Kriterien der Diagnose Albtraume wurden erstmals operationalisiert. Die Diagnose „Periodische Gliedmasenbewegungsstorung“ kann jetzt nicht mehr vergeben werden, wenn gleichzeitig ein Restless-Legs-Syndrom (RLS), eine Narkolepsie, eine REM-Schlaf-Verhaltensstorung oder ein unbehandeltes Schlafapnoesyndrom vorliegt. Bei vielen Bewegungsstorungen kommt ein Kriterium der klinischen Relevanz hinzu. Die isolierten Symptome und Norvarianten werden nun direkt den jeweiligen Diagnosegruppen zugeordnet.
- Published
- 2015
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35. Contrasting sea surface temperature of summer and winter monsoon variability in the northern Arabian Sea over the last 25 ka
- Author
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Birgit Gaye, Kay-Christian Emeis, Philipp Munz, Anna Böll, Hartmut Schulz, and Tim Rixen
- Subjects
Intertropical Convergence Zone ,Northern Hemisphere ,Holocene climatic optimum ,Paleontology ,Oceanography ,Monsoon ,Sea surface temperature ,Climatology ,Deglaciation ,East Asian Monsoon ,Ecology, Evolution, Behavior and Systematics ,Holocene ,Geology ,Earth-Surface Processes - Abstract
The seasonal monsoon cycle with winds from the southwest (SW) in summer and from the northeast (NE) in winter strongly impacts on modern regional sea surface temperature (SST) patterns in the Arabian Sea (northern Indian Ocean). To reconstruct the temporal and spatial variation in the dynamically coupled winter and summer monsoon strength over the last 25 ka, we analyzed alkenone-derived SST variations in one sediment core from the northwestern Arabian Sea, that is influenced by the summer monsoon (SST affected by upwelling processes), and in one core from the northeastern Arabian Sea, where SST is mainly governed by the winter monsoon (no upwelling). Comparison of the SST records reveals an antagonistic relationship of summer and winter monsoon strength throughout the late deglaciation and the Holocene. Upwelling along the Arabian Peninsula associated with peak SW monsoonal wind strength was strongest during the early Holocene climate optimum between 11 and 8 ka, and coincided with the northernmost position of the Intertropical Convergence Zone (ITCZ) marked by maximum precipitation over northern Oman. The SW monsoon weakened over the middle to late Holocene, while the NE monsoon gained strength. This different evolution was caused by the southward displacement of the ITCZ throughout the Holocene. Superimposed over the long-term trend are variations in northeast monsoon wind strength at time scales of centuries that were synchronous with late Holocene climate variations recorded on the Asian continent and in the high-latitude Northern Hemisphere. Their likely driving forces are insolation changes associated with sunspot cycles. Enhanced by feedback mechanisms (e.g. land-sea thermal contrast) they enforced centennial scale fluctuations in wind strength and temperature in the northern Arabian Sea monsoon system.
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- 2015
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36. Ergänzende Regeln zu Frequenzen und Graphoelementen der Schlafstadienanalyse
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Friedhart Raschke, A. Rodenbeck, H. G. Weeß, Hartmut Schulz, Peter Geisler, H. Danker-Hopfe, Ralf Binder, R. Lund, Task Force „Auswertung polysomnographischer Ableitungen' der Ag, and Kommission Ausbildung der Dgsm
- Subjects
Gynecology ,medicine.medical_specialty ,Physiology (medical) ,media_common.quotation_subject ,medicine ,Art ,media_common - Abstract
Das Manual der Amerikanischen Akademie fur Schlafmedizin (AASM) von 2007 ist gut etabliert, jedoch hat sich die Zuverlassigkeit von Schlafstadienauswertungen zwischen verschiedenen Auswertern im Vergleich zu den Regeln von Rechtschaffen und Kales nicht wesentlich verbessert. Neben den Regeln der Stadienzuordnung spielt die Erkennung von schlafrelevanten Frequenzen und Mustern eine wesentliche Rolle fur die Reliabilitat der Auswertung. Die Kommission Ausbildung der Deutschen Gesellschaft fur Schlafforschung und Schlafmedizin (DGSM) prufte und uberarbeitete daher die 2006 publizierten Empfehlungen zu Definitionen und Spezifikationen von α-, ϑ- und δ-Wellen sowie zu Vertex- und Sagezahnwellen, K-Komplexen und Schlafspindeln anhand des AASM-Manuals und der aktuellen Literatur. Durch uberarbeitete Spezifikationen sollen die Erkennung sowie die Beurteilung von Elektroenzephalographie(EEG)-Frequenzen und -Mustern fur die visuelle Schlafauswertung vereinheitlicht und verbessert werden. Die Uberarbeitung der Empfehlungen der DGSM Task Force von 2006 bezieht sich auf die relevanten EEG-Muster fur die Schlafstadienanalyse. Berucksichtigt werden α-, ϑ- und δ-Wellen, Vertexwellen, Schlafspindeln, K-Komplexe und Sagezahnwellen. Die Uberarbeitung erfolgte anhand der AASM-Manuale sowie der dazugehorigen Darstellung der Literatursichtung und der Entscheidungsfindung durch das AASM-Komitee. Des Weiteren wurde eine PubMed-Recherche durchgefuhrt. Auch wurde gepruft, ob neuere Versionen der damals verwendeten Leitlinien oder der einschlagigen Lehrbucher publiziert oder hinsichtlich neuerer Kriterien fur Frequenzen oder Graphoelemente aktualisiert wurden. Die 2006 im nominalen Gruppenprozess getroffenen Spezifikationen bleiben weitestgehend erhalten. Anderungen ergaben sich dem AASM-Manual entsprechend fur die Frequenzdefinition der Schlafspindeln sowie der ϑ- und Sagezahnwellen. Die Empfehlungen fur α- und δ-Wellen wurden erganzt, und die Festlegung der AASM auf eine zusatzliche okzipitale und eine frontale EEG-Ableitung berucksichtigt. Die Biosignaleichung muss mindestens jeweils 30 s mit offenen bzw. geschlossenen Augen dauern und abgespeichert werden. Zusatzlich wurden das Muster der niederamplitudigen, gemischtfrequenten EEG-Aktivitat („low amplitude, mixed frequency activity“, LAMF) sowie eine zusammenfassende Ubersicht der Frequenzdefinitionen eingefugt. Durch die vorgestellten uberarbeiteten Spezifikationen werden die Erkennung und die Beurteilung von EEG-Frequenzen und -Mustern fur die visuelle Schlafauswertung verbessert und vereinheitlicht. Alle vorgeschlagenen Spezifikationen sind konform mit den Auswerterichtlichtlinien des AASM-Manuals in der aktuellen Fassung 2.1 von 2014.
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- 2015
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37. Older Adults’ Engagement and Mood During Robot-Assisted Group Activities in Nursing Homes: Development and Observational Pilot Study
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Alexandra Tanner, Andreas Urech, Hartmut Schulze, and Tanja Manser
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Medical technology ,R855-855.5 - Abstract
BackgroundPromoting the well-being of older adults in an aging society requires new solutions. One resource might be the use of social robots for group activities that promote physical and cognitive stimulation. Engaging in a robot-assisted group activity may help in the slowdown of physical and cognitive decline in older adults. Currently, our knowledge is limited on whether older adults engage in group activities with humanlike social robots and whether they experience a positive affect while doing so. Both are necessary preconditions to achieve the intended effects of a group activity. ObjectiveOur pilot study has 2 aims. First, we aimed to develop and pilot an observational coding scheme for robot-assisted group activities because self-report data on engagement and mood of nursing home residents are often difficult to obtain, and the existing observation instruments do have limitations. Second, we aimed to investigate older adults’ engagement and mood during robot-assisted group activities in 4 different nursing care homes in the German-speaking part of Switzerland. MethodsWe developed an observation system, inspired by existing tools, for a structured observation of engagement and mood of older adults during a robot-assisted group activity. In this study, 85 older adult residents from 4 different care homes in Switzerland participated in 5 robot-assisted group activity sessions, and they were observed using our developed system. The data were collected in the form of video clips that were assessed by 2 raters regarding engagement (direction of gaze, posture as well as body expression, and activity) and mood (positive and negative affects). Both variables were rated on a 5-point rating scale. ResultsOur pilot study findings show that the engagement and mood of older adults can be assessed reliably by using the proposed observational coding scheme. Most participants actively engaged in robot-assisted group activities (mean 4.19, SD 0.47; median 4.0). The variables used to measure engagement were direction of gaze (mean 4.65, SD 0.49; median 5.0), posture and body expression (mean 4.03, SD 0.71; median 4.0), and activity (mean 3.90, SD 0.65; median 4.0). Further, we observed mainly positive affects in this group. Almost no negative affect was observed (mean 1.13, SD 0.20; median 1.0), while the positive affect (mean 3.22, SD 0.55; median 3.2) was high. ConclusionsThe developed observational coding system can be used and further developed in future studies on robot-assisted group activities in the nursing home context and potentially in other settings. Additionally, our pilot study indicates that cognitive and physical stimulation of older adults can be promoted by social robots in a group setting. This finding encourages future technological development and improvement of social robots and points to the potential of observational research to systematically evaluate such developments.
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- 2023
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38. Supplementary material to 'The C32 alkane-1,15-diol as a proxy of late Quaternary riverine input in coastal margins'
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Julie Lattaud, Denise Dorhout, Hartmut Schulz, Isla S. Castañeda, Jaap S. Sinninghe Damsté, and Stefan Schouten
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- 2017
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39. The C32 alkane-1,15-diol as a proxy of late Quaternary riverine input in coastal margins
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Julie Lattaud, Denise Dorhout, Hartmut Schulz, Isla S. Castañeda, Jaap S. Sinninghe Damsté, and Stefan Schouten
- Abstract
The study of past sedimentary records from coastal margins allows us to reconstruct variations of terrestrial input into the marine realm and to gain insight into continental climatic variability. There are numerous organic proxies for tracing terrestrial input into marine environments but none that strictly reflect riverine organic matter input. Here, we test the fractional abundance of the C32 alkane 1,15-diol relative to all 1,13- and 1,15-diols (F1,15-C32) as a tracer of riverine input in the marine realm in surface and Quaternary (0–45 ka) sediments on the shelf off the Zambezi and nearby smaller rivers in the Mozambique Channel (western Indian Ocean). A Quaternary (0–22 ka) sediment record off the Nile River mouth in the Eastern Mediterranean was also studied for diols. For the Mozambique Channel, surface sediments of sites most proximal to Mozambique rivers showed the highest F1,15-C32 (up to 10 %). The sedimentary record shows high (15–35 %) pre-Holocene F1,15-C32 and low (
- Published
- 2017
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40. Nanoprobe crystallographic orientation studies of isolated shield elements of the coccolithophore species Emiliania huxleyi
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Erika Griesshaber, Hartmut Schulz, Angela S. Wochnik, Sophia B. Betzler, Sonja Matich, Christina Scheu, Christoph Heinzl, Ramona Hoffmann, Jeremy R. Young, Michal Kucera, and Wolfgang W. Schmahl
- Subjects
Coccolith ,Crystallography ,biology ,Electron diffraction ,Geochemistry and Petrology ,Transmission electron microscopy ,Scanning electron microscope ,Coccolithophore ,Chemistry ,Resolution (electron density) ,Shell (structure) ,biology.organism_classification ,Emiliania huxleyi - Abstract
Coccolithophore algae produce elaborately structured skeletons composed of sub-micrometer-scale calcite crystals. In order to understand calcite crystallization and assembly in a coccosphere with nanoscale resolution, the crystal orientation and interdigitation of the structural units were investigated by transmission electron microscopy imaging, selected-area and nano-probe electron diffraction. Focused ion beam sectioning of coccoliths of the coccolithophore species Emiliania huxleyi is used to obtain target-prepared specimens in suitable orientation. We were able to detect and analyze the V-unit, which is overgrown by the R-unit. For the V-unit the 001 direction points perpendicular to the coccolith plane while the 110 axis is tangential to the coccolith ring. The R-unit c-axis is parallel and the b-axis is perpendicular to the coccolith plane, thus confirming the R- and V-model which was based on scanning electron microscopy and optical microscopy. Furthermore we show that the distal- and the proximal shield element of an individual R-unit of a single segment are tilted by 4 degrees +/- 1 degrees with respect to each other. This orientation change is required to obtain the flat domed character of the coccoliths, which is necessary to form the coccosphere. The orientation change between the distal- and the proximal shield element appears continuous.
- Published
- 2014
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41. Late Holocene primary productivity and sea surface temperature variations in the northeastern Arabian Sea: Implications for winter monsoon variability
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Birgit Gaye, Kay-Christian Emeis, Tim Rixen, Andreas Lückge, Sven Forke, Hartmut Schulz, Philipp Munz, Venkitasubramani Ramaswamy, and Anna Böll
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Sea surface temperature ,Alkenone ,Oceanography ,Continental margin ,Climatology ,Intertropical Convergence Zone ,Northern Hemisphere ,Paleontology ,East Asian Monsoon ,Monsoon ,Holocene ,Geology - Abstract
Variability in the oceanic environment of the Arabian Sea region is strongly 34 influenced by the seasonal monsoon cycle of alternating wind directions. Prominent and well studied is the summer monsoon, but much less is known about late Holocene changes in winter monsoon strength with winds from the northeast that drive convective mixing and highsurface ocean productivity in the northeastern Arabian Sea. To establish the first high resolution record of winter monsoon variability for the late Holocene, we analyzed alkenone derived sea surface temperature (SST) variations and proxies of primary productivity (organic carbon and δ15N) in a well-laminated sediment core from the Pakistan continental margin. Increased summer monsoon and weak winter monsoon intensities off Pakistan are indicated from 400 B.C. to 700 A.D. by reduced productivity and relatively high SST. At about 700 A.D. the intensity of the winter monsoon increased off Pakistan as indicated by a trend to lower SST. We infer that winter monsoon was still weak from 700 to 1400 A.D., because primary production did not increase despite decreasing SST. Declining SST and elevated biological production from 1400 to 1900 A.D. suggest invigorated convective winter mixing by strengthening winter monsoon circulation, most likely a regional expression of colder climate conditions during the Little Ice Age on the Northern Hemisphere. The comparison of winter monsoon intensity with records of summer monsoon intensity suggests that an inverse relationship between summer and winter monsoon strength exists in the Asian monsoon system during the late Holocene, effected by shifts in the Intertropical Convergence Zone.
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- 2014
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42. Towards radiocarbon dating of single foraminifera with a gas ion source
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Jörg Lippold, Hartmut Schulz, L. Wacker, and M Molnár
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Nuclear and High Energy Physics ,biology ,chemistry.chemical_element ,Mineralogy ,biology.organism_classification ,Ion source ,law.invention ,Foraminifera ,chemistry.chemical_compound ,chemistry ,law ,Carbonate ,Environmental science ,Sample preparation ,Radiocarbon dating ,Cibicides ,Instrumentation ,Carbon ,Accelerator mass spectrometry - Abstract
Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO 2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO 2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12 C − ion source current of 10–15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.
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- 2013
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43. Guidelines for the Recording and Evaluation of Pharmaco-Sleep Studies in Man: The International Pharmaco-EEG Society (IPEG)
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Marc, Jobert, Frederick J, Wilson, Thomas, Roth, Gé S F, Ruigt, Peter, Anderer, Wilhelmus H I M, Drinkenburg, Frederik W, Bes, Martin, Brunovsky, Heidi, Danker-Hopfe, Jon, Freeman, Joop M A, van Gerven, Georg, Gruber, Bob, Kemp, Gerhard, Klösch, Junshui, Ma, Thomas, Penzel, Barry T, Peterson, Hartmut, Schulz, Luc, Staner, Bernd, Saletu, and Vladimir, Svetnik
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Psychiatry and Mental health ,Neuropsychology and Physiological Psychology ,Polysomnography ,Pharmacology, Clinical ,Practice Guidelines as Topic ,Humans ,Electroencephalography ,Sleep ,Societies, Medical ,Biological Psychiatry - Abstract
The International Pharmaco-EEG Society (IPEG) presents guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-sleep data in man. Over the past years, technical and data-processing methods have advanced steadily, thus enhancing data quality and expanding the palette of sleep assessment tools that can be used to investigate the activity of drugs on the central nervous system (CNS), determine the time course of effects and pharmacodynamic properties of novel therapeutics, hence enabling the study of the pharmacokinetic/pharmacodynamic relationship, and evaluate the CNS penetration or toxicity of compounds. However, despite the presence of robust guidelines on the scoring of polysomnography -recordings, a review of the literature reveals inconsistent -aspects in the operating procedures from one study to another. While this fact does not invalidate results, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. The present guidelines are intended to assist investigators, who are using pharmaco-sleep measures in clinical research, in an effort to provide clear and concise recommendations and thereby to standardise methodology and facilitate comparability of data across laboratories.
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- 2013
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44. Decadal resolution record of Oman margin upwelling indicates persistent solar forcing of the Indian summer monsoon after the early Holocene summer insolation maximum
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Andreas Lückge, Anna Böll, Jeroen Groeneveld, Stephan Steinke, Hartmut Schulz, Philipp Munz, and Michal Kucera
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Insolation ,010506 paleontology ,010504 meteorology & atmospheric sciences ,Resolution (electron density) ,01 natural sciences ,Oceanography ,Indian summer monsoon ,Margin (machine learning) ,Climatology ,Upwelling ,Holocene ,Geology ,0105 earth and related environmental sciences ,Solar variation - Abstract
The Indian summer monsoon (ISM) brings most of the annual precipitation to the densely populated region in southern Asia. For the agricultural development and economic prosperity of the region, it is therefore vital to assess the variability of the monsoon system on societal relevant decadal- to centennial time scales. This might help to better understand how potential driving forces might be controlling ISM variability and how it might develop under future climate scenarios. Here we present a study of a sediment core from the northern Oman margin, revealing early- to mid Holocene ISM conditions on a near 20-year resolution. We assess multiple independent proxies indicative of sea surface temperatures (SST) during the upwelling season together with bottom water conditions. We use geochemical parameters, transfer functions of planktic foraminiferal assemblages and Mg/Ca paleothermometry and find evidence corroborating previous studies that upwelling intensity varies significantly in coherence to solar sunspot cycles. The dominant ~80–90-year Gleissberg cycle was apparently also affecting bottom water oxygen conditions. Although the interval from 8.4 to 5.8 ka B.P. is relatively short, the gradually decreasing trend of summer monsoon conditions was interrupted by short events of intensified ISM conditions. Results from both independent SST proxies are linked to phases of weaker OMZ conditions and enhanced carbonate preservation. This indicates that atmospheric forcing was intimately linked to bottom water properties and state of the OMZ on decadal time scales.
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- 2016
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45. Impact of Indus River discharge on productivity and preservation of organic carbon in the Arabian Sea over the twentieth century
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Georg Scheeder, Hartmut Schulz, Andreas Lückge, Axel Suckow, Sabine Kasten, Gaudenz Deplazes, and Gerald H. Haug
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Total organic carbon ,chemistry.chemical_classification ,010504 meteorology & atmospheric sciences ,Discharge ,Indus ,Geology ,010502 geochemistry & geophysics ,Oxygen minimum zone ,01 natural sciences ,Carbon cycle ,Oceanography ,Productivity (ecology) ,chemistry ,13. Climate action ,Period (geology) ,Organic matter ,14. Life underwater ,0105 earth and related environmental sciences - Abstract
Marine high-productivity zones along the continents are of great economic importance, and they account for most organic carbon burial. The carbon cycle in many coastal zones is influenced by the sediments and dissolved nutrients introduced by rivers. However, there is little direct evidence for a regional marine response to changes in river dynamics. Here we present a suite of high-resolution records of organic and inorganic paleoceanographic proxies, which together demonstrate that past changes in Indus River discharge have strongly affected productivity patterns in the coastal northeastern Arabian Sea. Anthropogenic activity, including the building of dams and irrigation facilities during the past century, has drastically decreased the discharge rate of the Indus River. Between A.D. 1890 and 1998, the period over which this reduction occurred, primary productivity off the Pakistan coast seems to have decreased by more than one-third. Over the same period, the regional oxygen minimum zone weakened, increasing the supply of oxygen to the sediments, leaving the expected imprint on a suite of redox-sensitive elements and reducing the preservation of organic matter.
- Published
- 2012
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46. Evaluation of environmental magnetic pollution screening in soils of basaltic origin: results from Nashik Thermal Power Station, Maharashtra, India
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K. Deenadayalan, U. Blaha, Prabir Kumar Das, Nathani Basavaiah, Hartmut Schulz, and M. B. Sadashiv
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Pollution ,Ash pond ,Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,India ,Industrial Waste ,Mineralogy ,Soil ,Soil Pollutants ,Environmental Chemistry ,media_common ,Topsoil ,Magnetic Phenomena ,Silicates ,General Medicine ,Thermomagnetic convection ,Particulates ,equipment and supplies ,Magnetic susceptibility ,Metals ,Remanence ,Microscopy, Electron, Scanning ,Magnetic nanoparticles ,human activities ,Geology ,Environmental Monitoring ,Power Plants - Abstract
Soils of basaltic origin cause difficulties in environmental magnetic screening for heavy metal pollution due to their natural high background values. Magnetic parameters and heavy metal content of highly magnetic topsoils from the Deccan Trap basalts are investigated to assess their potential for use in environmental magnetic pollution screening. This work extends the fast and cost-effective magnetic pollution screening techniques into soils with high natural magnetic signals. Fifty-five topsoil samples from N–S and W–E transects were collected and subdivided according to grain size using wet sieving technique. Magnetic susceptibility, soft isothermal remanent magnetization (Soft IRM), thermomagnetic analysis, scanning electron microscopy (SEM), and heavy metal analysis were performed on the samples. Magnetic analyses reveal a significant input of anthropogenic magnetic particulate matter within 6 km of the power plant and the adjacent ash pond. Results depend strongly on the stage of soil development and vary spatially. While results in the W, E, and S directions are easily interpretable, in the N direction, the contribution of the anthropogenic magnetic matter is difficult to assess due to high magnetic background values, less developed soils, and a more limited contribution from the fly ash sources. Prevailing winds towards directions with more enhanced values seem to have a certain effect on particulate matter accumulation in the topsoil. Thermomagnetic measurements show Verwey transition and Hopkinson peak, thus proving the presence of ferrimagnetic mineral phases close to the pollution source. A quantitative decrease of the anthropogenic ferrimagnetic mineral concentration with increased distance is evident in Soft IRM measurements. SEM investigations of quantitatively extracted magnetic particles confirm the fly ash distribution pattern obtained from the magnetic and heavy metal analyses. Evaluation of magnetic and chemical data in concert with the Pollution Load IndiceS (PLIS) of Pb, Zn, and Cu reveals a good relationship between magnetic susceptibility and the metal content. Integrated approaches in data acquisition of magnetic and chemical parameters enable the application of magnetic screening methods in highly magnetic soils. Combined data evaluation allows identification of sampling sites that are affected by human activity, through the deviation of the magnetic and chemical data from the general trend. It is shown that integrative analysis of magnetic parameters and a limited metal concentration dataset can enhance the quality of the output of environmental magnetic pollution screening significantly.
- Published
- 2012
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47. Forerunners of REM sleep
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Hartmut Schulz and Piero Salzarulo
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Biomedical Research ,Sleep, REM ,Sleep spindle ,Audiology ,Electroencephalography ,Non-rapid eye movement sleep ,Rhythm ,Physiology (medical) ,Psychophysics ,medicine ,Humans ,Slow-wave sleep ,Ultradian rhythm ,medicine.diagnostic_test ,Penile Erection ,Eye movement ,History, 19th Century ,History, 20th Century ,Dreams ,Neurology ,Neurology (clinical) ,K-complex ,Psychology ,Neuroscience - Abstract
Summary The development of sleep research can be divided into two main periods. The first one was initiated in 1863 by the first systematic measurement of the depth of sleep, the second in 1953 by the discovery of recurrent episodes of rapid eye movements in sleep. The main methodological procedure in the first of these two periods was the measurement of a single physiological variable, while beginning with long-term measurements of the electroencephalogram (EEG) in sleep, multi-channel, polygraphic recording became the method of choice for sleep studies. Although rhythmic changes in the ultradian frequency range of one to 2 h were observed early in many variables during sleep (movements, autonomic functions, penile erections), the recognition of the existence of two different states of sleep (rapid eye movement (REM) and non-rapid eye movement (NREM sleep)) was contingent upon a ‘synthetic' view, which focus on the coalescence of multiple variables. The dual concept of sleep organization evolved stepwise in parallel to the rapid growth of neurophysiological knowledge and techniques in the first half of the 20th century, culminating in the discovery of REM sleep.
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- 2012
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48. Sedimentology and geochemistry of an exceptionally preserved last interglacial sapropel S5 in the Levantine Basin (Mediterranean Sea)
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Tobias Moller, Michal Kucera, Hartmut Schulz, Yvonne Hamann, and Olaf Dellwig
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Eemian ,Mediterranean sea ,Geochemistry and Petrology ,Terrigenous sediment ,Interglacial ,Marl ,Geochemistry ,Sediment ,Geology ,Sapropel ,Sedimentology ,Oceanography - Abstract
A combined study of lithological, geochemical and physical sediment properties is reported from a completely laminated S5 sapropel, recovered in three gravity cores (M40-4 SL67, M51-3 SL103, M51-3 SL104) from the Pliny Trench region of the eastern Mediterranean. The thickness of the studied sapropel S5 varies between 85 and 91 cm and tops most S5-sapropels in the Mediterranean. Based on optical features like color and thickness of laminae, the sapropels were subdivided into thirteen distinct lithostratigraphic zones. These zones, as well as the finer layering pattern within them, could be followed exactly among the three cores, indicating that the processes responsible for this variation acted at least on a regional scale. The sapropel sediment is characterized by exceptionally high porosity, which is strongly correlated with Si/Ca. This relationship implies that the sapropel is in essence an organic-matter rich diatomite and its exceptional thickness can be explained by preservation of diatoms forming a loosely packed sediment fabric. Compared to other S5 sapropels, the preservation of diatoms has apparently led to a twofold increase in the thickness of the sapropel layer. Relative abundances of 10 elements were determined at ultra-high resolution (0.2 mm) by XRF-scanner over the complete length of each sapropel including several cm of enclosing marl. An analysis of the chemical data indicates that the lowermost 13 cm of the sapropel is chemically more similar to the underlying marl and that the sediment chemistry shows different signals at different scales. The strongest pattern is the contrast between the sapropel and the surrounding marl, which is accentuated in elements indicative for redox conditions as well as terrigenous sediment input and productivity. Within the sapropel, a mm- to cm-scale layering is observed. The abundances of many elements are systematically linked to the pattern of these layers, indicating a common origin, related to productivity and/or terrigenous sediment and/or redox conditions. This pattern indicates a link to a regional climatic process, making the S5 sapropel horizon in M40-4 SL67, M51-3 SL103 and M51-3 SL104 a potential high-resolution archive of climatic variability during the last interglacial in the Mediterranean Sea and its adjacent landmasses.
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- 2012
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49. Fatigue, sleepiness, and physical activity in patients with multiple sclerosis
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F. Hoffmann, J. Klingelhöfer, R. Dachsel, U. Polzer, Hartmut Schulz, G. Gora, S. Merkelbach, and H. W. Kölmel
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Adult ,Male ,Aging ,medicine.medical_specialty ,Multiple Sclerosis ,Neurology ,Rest ,Neurological disorder ,Motor Activity ,Central nervous system disease ,Multiple Sclerosis, Relapsing-Remitting ,medicine ,Humans ,In patient ,Fatigue ,Sleep disorder ,Multiple sclerosis ,Epworth Sleepiness Scale ,Actigraphy ,Middle Aged ,medicine.disease ,Disease Progression ,Physical therapy ,Female ,Sleep Stages ,Neurology (clinical) ,Psychology - Abstract
Fatigue is a frequent and disabling symptom in patients with multiple sclerosis (MS). The objective of the study was to compare fatigue and sleepiness in MS, and their relationship to physical activity. Eighty patients with MS rated the extent of experienced fatigue (Fatigue Severity Scale, FSS) and sleepiness (Epworth Sleepiness Scale, ESS). The relationship between the scales was analysed for the scales as a whole and for single items. The clinical status of the patients was measured with the Extended Disability Status Scale (EDSS). In addition, physical activity was recorded continuously for 1 week by wrist actigraphy. The mean scores of fatigue and sleepiness were significantly correlated (FSS vs. ESS r = 0.42). Single item analysis suggests that fatigue and sleepiness converge for situations that demand self-paced activation, while they differ for situations in which external cues contribute to the level of activation. While fatigue correlated significantly with age (r = 0.40), disease severity (EDSS, r = 0.38), and disease duration (r = 0.25), this was not the case for sleepiness. Single patient analysis showed a larger scatter of sleepiness scores in fatigued patients (FSS > 4) than in non-fatigued patients. Probably, there is a subgroup of MS patients with sleep disturbances that rate high on ESS and FSS. The amount of physical activity, which was measured actigraphically, decreased with disease severity (EDSS) while it did not correlate with fatigue or sleepiness.
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- 2010
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50. Die geschichtliche Entwicklung der Schlafforschung in Berlin
- Author
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Hartmut Schulz
- Subjects
Physiology (medical) ,media_common.quotation_subject ,Sleep research ,Art ,Early phase ,Sleep eeg ,Humanities ,media_common - Abstract
Teil I der Geschichte der Schlafforschung in Berlin zeichnete die Entwicklung von der Aufklarung im 17. Jh. bis zur Periode der fruhen Physiologie zu Beginn des 19. Jh. nach. Ab dieser Zeit wurde die medizinische Fakultat der Universitat Berlin ein fuhrendes Zentrum der Physiologie und der klinischen Forschung in Deutschland. In der 1. Halfte des 20. Jh. starkte besonders die Errichtung des Instituts fur Hirnforschung in Berlin-Buch durch die Kaiser-Wilhelm-Gesellschaft die Hirnforschung. Kurz nach den ersten Veroffentlichungen von Hans Berger uber das Elektroenzephalogramm (EEG) richteten Alois Kornmuller und Mitarbeiter an diesem Institut ein straffes EEG-Forschungsprogramm ein. In diesem Rahmen erkannte Klaue 1936 als Erster 2 unterschiedliche Arten von Schlaf bei der Katze, und die neue Schlaf-EEG-Methode wurde bei Patienten mit Schlaf-Wach-Storungen eingesetzt, so z. B. bei der Narkolepsie. Diese vielversprechenden Entwicklungen kamen am Vorabend des II. Weltkriegs abrupt zum Stillstand. Nach dem Krieg und der Teilung Berlins dauerte es mehr als 20 Jahre, bevor Schlafforschung wieder in mehreren akademischen Einrichtungen in Ost- und West-Berlin betrieben wurde. Kurz vor der Wiedervereinigung Deutschlands waren 4 Berliner Schlaflabore bei der deutschen Gesellschaft fur Schlafforschung und Schlafmedizin (DGSM) gemeldet, 2 im Ostteil und 2 im Westteil der Stadt. Heute sind 10 Schlaflabore in Berlin von der DGSM akkreditiert. In Zukunft ist die Grundlagenforschung im Schlafgebiet zu starken, als notwendige Basis fur die breit entwickelte Schlafmedizin.
- Published
- 2010
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